Stone Paper Production Line
Stone Paper; A New Generation of Eco-Friendly Paper
Paper has always been one of the main pillars of the development of knowledge, culture and human communication. While the annual per capita consumption of paper in industrialized countries is about 170 kilograms and in developing countries about 20 kilograms, the pressure on natural resources such as forests and water has pushed the paper industry towards more sustainable solutions. In the meantime, stone paper has been proposed as an innovative, environmental and economic alternative to traditional paper.
Stone paper production methods
Depending on the final need, type of product and desired thickness, stone paper production is carried out through three main methods:
1. Blowing method:
In this method, polymer granules and stone powder are melted in an extruder and passed through a ring die with the help of compressed air to form thin films. This process is mostly used for producing lightweight rolls, advertising bags, and packaging films. High speed and low cost are the main advantages of this method, but the control of thickness and surface uniformity is less than other methods.
2. Casting method:
In the Casting process, molten materials are poured onto a flat surface or cold drum, and after cooling, sheets with very precise thickness and a smooth and matte surface are obtained. This method is suitable for producing high-quality thin films for graphic applications, precision printing, and delicate packaging.
3. Calendering method:
The most basic and widely used industrial method for producing strong and thick sheets of stone paper. In this method, semi-molten materials are passed through several rollers at a controlled temperature to form sheets. The oldest method of producing stone paper is the Calendering method.
This method was first developed in Taiwan in the 1990s by companies such as Taiwan Lung Meng (TLM). At that time, casting and blowing technology had not yet matured to combine stone and polymer in a sustainable and industrial way. Calendering, using technologies common in the PVC and plastic sheet industries, allowed for the compression of materials and sheet forming.
Outstanding advantages of the calendering method:
- Very good control over sheet thickness and uniformity
- Production of sheets with a glossy, polished and resistant surface
- High production speed and usability in high-volume lines
- Compatible with recycled and economical granules on an industrial scale
- Suitable for the production of notebooks, boxes, labels, posters and resistant packaging sheets
Advantages of stone paper:
- Non-forest raw materials: produced from calcium carbonate powder (limestone) and biocompatible polymers
- Environmentally friendly: no need to cut down trees or consume water in the production process
- High resistance: waterproof, tear-resistant, resistant to mold and rot
- High-quality surface: very good printability due to surface uniformity
- Recyclable: possibility of recycling in industrial cycles and natural decomposition in the environment
- These features have made stone paper a suitable option for packaging, printing, advertising and even industrial applications.
Key equipment in the stone paper production line:
- Granulator: Converting raw materials into granules by high-speed mixer, dosing, extruder and dryer
- Blowing or Calendering or Casting machine (depending on the type of line)
- Coating unit: Improving the appearance and strength of the sheet
- Slitting: Dividing the roll into desired widths
- Cutting: Preparing the sheets in final dimensions
Stone paper is a modern solution for replacing wood-based papers and based on the required final product characteristics, the best method for production will be suggested.
| Features / methods | Calendering | Casting | Blowing |
| Process type | Material passing through several rollers | Pouring the melt onto a flat surface or drum | Blowing molten material from inside a ring mold with air pressure |
| Product structure | Dense and shiny sheet with compact structure | Flat film with very uniform thickness | Semi-transparent and flexible inflatable film |
| Surface quality | Glossy and uniform, may have roller marks | Very smooth and polished | Soft, flexible surface, but slightly more matte |
| Thickness control | Good, but for medium to high thicknesses | Very accurate for thin films | More difficult for uniform thickness |
| Producible thickness | Medium to thick (e.g. 80-400 microns) | Thin to medium (e.g. 30 - 150 microns) | Thin, usually less than 100 microns |
| Production speed | up | average | very high |
| Energy consumption | optimal | medium to high | Less is more economical in high circulation) |
| suitable for | Industrial Thick Sheet Durable Packaging Sheets | Packaging with precise labels and high graphic quality | Thin Film Roll Printing Promotional Bags |
| Equipment cost | average | up | Low to medium |
| Ability to use recycled granules | has | with proper pre-processing | Yes, but depends on the quality of the melt |
| Dimensional stability | up | very high | Less than the other two methods |
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