Industry News

Products like baking paper, air fryer paper, and hamburger wrapping paper play a pivotal role in the food packaging industry. So, how is food wrapping paper produced? How can food wrapping paper, beyond its practical value of oil and water resistance, become a brand's "primary salesperson"? This article will explain the four steps involved: raw material selection, pulping and forming, process treatment, flexographic printing.

CI Type Flexo Printing Machine for Biscuit Wrapping Paper

Raw Material Selection

Food wrapping paper, such as hot dog wrapping paper and sandwich wrapping paper, is typically made from food-grade natural wood pulp (such as softwood and hardwood pulp). To enhance toughness and environmental friendliness, some products also incorporate bamboo pulp or recycled fiber. Raw materials should be adjusted accordingly if high-temperature, high-fat, frozen, or microwave heating requirements are required. All raw materials must meet food contact standards and must not contain harmful substances such as fluorescent brighteners and plasticizers.

Stack Flexographic Printing Machine for Fruits Wrapping Paper

Pulping and Forming

Pulping and forming mainly consists of the steps of pulp refining, additive dosing, wire section dewatering, pressing and forming.

Pulp Refining：the wood pulp is crushed and beaten into long fibers to improve the strength for food packaging such as pizza wrapping paper.

Additive Dosing：nanocellulose, wet strength agents, dry strength agents, antimicrobial agents, etc. may be added to improve oil-proof, water-proof and tear-resistant properties.

Wire Section Dewatering & Pressing and Forming: The pulp is evenly spread on the wire mesh through the papermaking machine, dehydrated to form a wet paper web, and then pressed and preliminarily dried.

Inline Flexo Printing Machinery for Vegetables Wrapping Paper

Processing

Common processing methods include lamination or coating, calendering, etc.

Lamination or Coating

Apply a layer of food-grade oil-proof coating to the paper surface to create an oil- and water-resistant barrier.

Moisture and Grease Resistance: PE, PP, water-based acrylic-EVOH coatings can be used, suitable for French fries wrapping paper, cookie wrapping paper, etc.

Oxygen Barrier and Freshness Preservation: aluminum foil composite coatings can be used, suitable for chocolate wrapping paper, tea wrapping paper, etc.

Calendering

Calendering is not to make the raw material of food tray liner paper, cake wrapping paper, etc. thinner, but to improve the surface smoothness, density, and tightness through high-pressure and roller pressing, to restore the printing dots, and to improve the printing suitability and the uniformity of the oil-proofing.

Central Drum Flexo Press for Coffee Bean Wrapping Paper

Flexo Printing

Printing with flexographic press enables high-definition, multi-color overprinting of products such as butter wrapping paper and fried chicken wrapping paper to enhance visual appeal. Its steps can be roughly divided into pre-press processing, flexographic printing, drying, and post-press processing.

Pre-Press Processing

Corona Treatment: use corona processor to treat, otherwise water-based ink will not adhere firmly.

Tension Setting: unwind tension = (substrate gram weight x width x 0.7) ±10 N, to avoid substrate stretching and deformation when it enters the printing unit.

Dust and Static Electricity Removal

Stacking Flexographic Printer for Nougat Wrapping Paper

Flexographic Printing

The fountain cylinder pick up ink and pass ink to the anilox cylinder. The the doctor blade removes the excess ink from the smooth non-engraved portions of the anilox roll and the land areas of the cell walls. Anilox cylinder even spread ink in the surface of the flexible plate. Impression cylinder and plate cylinder press substrate and transfer ink to substrate material surface.

Central Impression Flexo Printer for Hot Dog Wrapping Paper

Drying

Flexography machines can be dried by hot air, infrared or UV curing.

Hot air drying dries the ink by evaporating the water or solvent in the ink by hot air, which is suitable for paper, PE/PLA laminated paper and other substrates.

Infrared (IR) drying utilizes infrared radiation energy to act directly on the ink layer, accelerating solvent evaporation, and is suitable for water-based inks and UV inks, especially for highly absorbent substrates such as paper.

UV curing and drying is done through ultraviolet light irradiation so that the photoinitiator in the ink triggers a polymerization reaction, causing the ink to cure instantly. It is suitable for UV inks, especially for scenarios that require fast curing and high food safety requirements.

CI Drum Flexographic Machine for Cake Wrapping Paper

Post-Press Processing

Flexographic printing press can be connected with slitting unit and die-cutting unit to cut candy wrapping paper, chocolate wrapping paper, tea wrapping paper, etc. in specific sizes according to customer's requirements, which is a multifunctional and highly efficient solution for quick packaging. The versatility of this unit is extremely efficient for fast packaging.

Central Cylinder Flexo Presses for Coffee Bean Wrapping Paper

Through a series of manufacturing processes, products like bread wrapping paper, barbecue paper, and instant noodle wrapping paper not only achieve practical oil and water resistance but also, through exquisite patterns and brand logos, become a bridge of communication between brands and consumers. This article's detailed introduction to the four key processes—raw material selection, pulping and forming, process treatment, flexographic printing—is hoped to be helpful to manufacturers.