Curious metal paper is a unique material that has properties of both paper and metal. It looks and feels like regular paper, but has the strength, durability, and conductivity of metal. Curious metal paper is made by embedding thin layers of metal into the fibers of paper during manufacturing. This gives the paper metal-like capabilities while retaining the flexibility, printability, and recyclability of normal paper.
History
Curious metal paper was originally developed in the early 2000s by researchers at the Karlsruhe Institute of Technology in Germany. They were looking for ways to create paper-based electronics by integrating conductive materials into paper. Through experimentation with different metals and paper fibers, they created the first samples of curious metal paper.
Initially, curious metal paper was produced solely for research purposes. Scientists used it to create paper-based batteries, capacitors, sensors, antennas, and other electronic components. However, over time, companies realized the material had potential commercial applications as well.
In 2007, a Swedish company called Graphic Plc licensed the technology and began manufacturing curious metal paper on an industrial scale. They branded their product as “Power Paper” and marketed it for uses such as RFID tags, smart packaging, wearable sensors, and disposable electronics. Other companies around the world have since begun producing their own versions of curious metal paper.
While originally a niche product, curious metal paper has grown steadily in popularity and availability over the past decade. It is now used in a wide range of industries including packaging, printing, automotive, aerospace, healthcare, and consumer electronics.
Production Process
Curious metal paper is produced through a process called substrate metallization. The basic steps are:
- Start with a base of cellulose paper.
- Treat the paper with chemicals to make it porous and receptive to metals.
- Coat the paper with a thin layer of metal using physical vapor deposition.
- Repeat coating to build up multiple metal layers within the paper.
- Coat paper with a protective lacquer layer.
- Cut, print, or process the metallized paper as needed.
The metals most commonly used to make curious metal paper are aluminum, copper, nickel, and stainless steel. The thickness and pattern of the metal coatings can be controlled to achieve the desired electrical, thermal, and optical properties.
One key advantage of curious metal paper is that it can be produced on standard paper machines with some modifications. This makes it cost-effective compared to other conductive sheet materials.
Properties
Here are some of the unique properties of curious metal paper:
- Conductivity – The embedded metal layers make curious metal paper electrically conductive, able to carry currents.
- Shielding – It blocks electromagnetic interference from radio waves and microwaves.
- Reflectivity – Metallized paper is reflective to light and heat.
- Barrier – The metal layers provide a barrier to moisture, oxygen, and other gases.
- Heat resistance – Withstands heat up to 230°C based on metal coatings.
- Toughness – Has up to 5 times the tensile strength of regular paper.
- Solderable – Metal coatings allow electrical components to be soldered onto the paper.
- Printable – Can be printed on using conventional printing methods.
- Flexible – Retains the ability to bend and fold like regular paper.
These properties make curious metal paper suitable for a wide range of applications that regular paper cannot support. However, it remains lightweight, thin, and easy to cut and process just like paper.
Applications
Here are some of the main ways curious metal paper is used:
Electronics
Curious metal paper allows electronics like batteries, antennas, capacitors, and sensors to be embedded into paper substrates. This enables ultra-thin and flexible paper electronics. Specific applications include:
- Disposable diagnostic devices
- RFID and NFC tags
- Smart labels and packaging
- Wearable medical sensors
- Interactive media
Shielding & EMI Protection
The metal layers in curious metal paper block electromagnetic interference (EMI). It is used to shield electronics and prevent interference:
- EMI shielding in motors
- Automotive electronics shielding
- Protecting medical devices
- Aircraft electronics shielding
Heating Elements
When current is passed through curious metal paper, the resistive metal layers produce heat. This allows curious metal paper to be used in heating applications such as:
- Defoggers and de-icers in vehicles
- Heating pads and flexible heaters
- Heat shields and reflective insulation
Packaging & Labelling
Curious metal paper provides an enhanced substrate for packaging, labels, and tags. Uses include:
- Anti-counterfeiting labels
- Tamper-evident packaging
- Insulating liners and divider sheets
- Reflective envelopes and pouches
Printed Electronics
Curious metal paper can be fed through standard printers and coated with conductive inks to print circuits and components. This allows customized printed electronics.
Manufacturers
Here are some of the major manufacturers producing curious metal paper worldwide:
| Company | Brand Name | Location |
|---|---|---|
| Graphic PLC | Power Paper | Sweden |
| Sporea | MetaPaper | Finland |
| Henan Huatai | Huatai Paper | China |
| Dunmore Corp. | Dun-On-Paper | USA |
| Vorbeck Materials | Vor-ink | USA |
Cost Analysis
Curious metal paper is generally more expensive than regular paper due to the specialized production process. Here is a comparison of curious metal paper costs versus standard printing paper:
| Paper Type | Cost Per Sheet |
|---|---|
| Standard 20lb Printing Paper | $0.02 – $0.05 |
| Curious Metal Paper (Aluminum) | $0.15 – $0.30 |
| Curious Metal Paper (Copper) | $0.25 – $0.60 |
The cost depends on the type and thickness of metal coatings used. Copper and silver curious metal paper is more expensive than aluminum. Costs also scale down significantly for large volume orders. Despite the higher price, the value provided by curious metal paper’s advanced properties justify the cost for many applications.
Advantages
Here are some of the main advantages of using curious metal paper:
- Combines properties of paper and metal
- Printable and writable like regular paper
- Highly conductive for electronics
- Thin, lightweight, and flexible
- Easy to cut, shape, and process
- Compatible with paper production and printing
- Lower cost than pure metal foils
- Recyclable and eco-friendly
Disadvantages
There are also some limitations to be aware of when using curious metal paper:
- More expensive than regular paper
- Limited supply and production capacity
- Requires special tools and adhesives
- Metal layers prone to scratching and wear
- Not compatible with some printing processes
- Thermal management issues at high currents
The Future
Curious metal paper is an advanced material that merges the worlds of paper and electronics. As production volumes increase and costs decrease, curious metal paper has the potential to enable smart paper-based devices to become ubiquitous. Future applications could include:
- Biodegradable transient electronics
- Wallpaper antennas and sensors
- Rapid prototyping of circuits
- Self-powered paper diagnostics
- origami and morphing electronic devices
- Paper-based robots and machines
While still in its early stages, curious metal paper represents a transformative platform for printing, electronics, packaging, and many other fields.
Conclusion
Curious metal paper is an innovative hybrid material that brings together paper and metal. By embedding thin metallic layers into paper fibers, curious metal paper gains the conductivity, shielding, reflectance, and strength of metal while retaining the flexibility, printability, and feel of paper. Since its development in the 2000s, curious metal paper has evolved from a niche research material into a viable product used in electronics, shielding, heating, packaging, and many other applications. As production expands globally, curious metal paper promises to enable the next generation of ultra-thin, eco-friendly printed electronics and smart paper devices.
