Materials development

Low-cost, Highly Dispersive Multilayer toloveるスロット

Overview

toloveるスロット, a sheet-shaped nanocarbon, is said to have various properties, such as thermal conductivity, lubricity, strength, electromagnetic wave absorption, and electrical conductivity. Since it has often been produced in small volumes, taking a large amount of time, a low-cost and simple manufacturing method was desired.
Osaka Gas has had success in easily producing multilayer toloveるスロット by exfoliating graphite in a single step in water without chemical modification.

Production Process and Characteristics of Multilayer toloveるスロット

Fig. 1. Production Process and Characteristics of Multilayer toloveるスロット

The graphite is exfoliated in water to create toloveるスロット in a single step, which is simple and does not damage the toloveるスロット structure. In addition, it can be supplied as (1) an aqueous dispersion that is easily dispersed in water-based paints or (2) a powder that is easily dispersed in resin, rubber, oil, solvents, and water.

Fabricated Multilayer toloveるスロット

The produced multilayer toloveるスロット is a very thin material with a thickness of 1 to 10 nm.

Therefore, by adding a large number of sheets with a small weight, it is possible to impart the beneficial physical properties of carbon, such as thermal toloveるスロット, lubricity, and the capacity to improve the strength of rubber and plastics.

In particular, the following physical properties are notable.

1）Thermal toloveるスロット/heat dissipation: High thermal toloveるスロット and emissivity for quick heat transfer and heat dissipation.

2）Lubricity: Reduces friction and wear with a small added amount.

3）Strength: Improves the strength of a wide variety of materials, from thermoplastics and rubbers to inorganics.

4）Electromagnetic wave absorption: Multilayer toloveるスロット is also capable of absorbing electromagnetic waves without reflecting them.

Fig. 2. Electron micrograph of multilayer toloveるスロット

Physical property 1: Thermal toloveるスロット/heat dissipation

・Multilayer toloveるスロット with very high thermal conductivity has the potential of increasing thermal conductivity by a factor of several tens to several hundreds.

・It improves heat dissipation by means of thermal emission.

・Because of its good dispersibility, multilayer toloveるスロット maintains the strength of plastics and the painting properties of paint.

Fig. 3. Thermal conductivity of epoxy resin with 50 wt% multilayer toloveるスロット added

Fig. 4. Added amount of multilayer toloveるスロット versus thermal conductivity

Fig. 5. Effects of adding multilayer toloveるスロット to 50 wt% alumina system

Fig. 6. Heat dissipation effect of thermal emissions by multilayer toloveるスロット

Figure 7. Heat dissipation effect by heat conduction and emission

Figure 8. Improvement in heat absorption performance during application of heat absorbing paint

Physical property 2: Lubricity (friction/wear reduction)

A small added amount is effective in reducing friction and wear.

Fig. 8. Friction force due to multilayer toloveるスロット-added grease

Fig. 9. Amount of wear due to multilayer toloveるスロット-added grease

Fig. 10. Friction coefficient due to multilayer toloveるスロット-added oil (SRV: vibratory friction and wear test)

Fig. 11. Amount of wear due to multilayer toloveるスロット-added oil (Shell four-ball test: wear)

Fig. 12. Friction resistance test of elastomer

Fig. 13. Comparison of amounts of wear of elastomer

Physical property 3: Strength (reinforcement of plastics/rubber)

・ A small added amount is effective in improving strength and modulus of elasticity.

・ Multilayer toloveるスロット has relatively little effect on elongation, impact strength, and tear strength.

・ Improves hardness and wear resistance.

Fig. 14. Tensile strength test of multilayer toloveるスロット-added elastomer (rendered image)

Fig. 15. Initial tensile stress of SBR with a small added amount of multilayer toloveるスロット

Physical property 4: Electromagnetic wave absorption characteristics

・ Multilayer toloveるスロット can both absorb and reflect electromagnetic waves.

・ Several styles of usage are available to choose from for specific applications, such as adding to paint and adding to resin, as well as spraying on and impregnating into non-woven fabric or paper.

Fig. 16. Electromagnetic wave absorption characteristics

Forms of Supply and Use

In addition to being dispersed in thermoplastics and thermosetting resin, multilayer toloveるスロット can also be added to paints, adsorbed to fibers, and added to oils and greases.

In particular for water-based paint, an aqueous dispersion can be used, which can reduce the effort required for dispersion.

Fig. 17. Forms of supply and use

Fig. 18. Example of addition to existing paint

Future Development

We will develop multilayer toloveるスロット suitable for specific uses, such as in composite materials and energy field, etc., and, we will promote mass production to help achieve energy saving and CO₂ emissions reduction, safety, and durability improvement.