Regarding the provision of flame retardancy to cellulose nanofibers, there is still very little empirical data, and I think this is an area that will be examined by manufacturers in the future.
⇒ Consideration of coating type flame retardant using cellulose nanofiber
Specifically, the flame retardant will be kneaded in the formation stage. When trying to increase the strength by kneading the plastic resin and cellulose nanofiber, it may be effective to mix an effective flame retardant into the plastic side.
However, according to research, it is said that the strength of the plastic resin will not increase unless a certain amount of CNF is mixed, so it may be necessary to apply flame retardant treatment to the CNF side as well.
It would be best if the plastic and CNF had a flame retardant that was highly effective at the same time.
However, many plastic flame retardants have a high environmental impact and do not want to use them much. In that case, it is necessary to impart flame retardancy to the CNF with a unique flame retardant.
The effective flame retardant for cellulose is boric acid or phosphoric acid. Many of the flame retardants used in the manufacture of non-combustible wood are boric acid or phosphoric acid or a mixture thereof. Curiously, there is little interaction with the chemical industry regarding flame retardant technology for non-combustible wood, and non-combustible wood is being researched independently by each company.
In addition, since few companies sell only drugs, the details of these flame retardants are not well understood.
However, these flame retardants are not perfect, and there are various issues regarding flame retardancy of wood.
Generally, boric acid is said to be effective. Phosphoric acid also appears to be effective, but is not preferred because it can cause leaching problems and adversely affect the material.
However, there is almost no flame retardant made of boric acid alone, so demand is concentrated on some products.
We also do a little testing.
The results are good so far.
However, we have not yet constructed data that can be displayed on the table.
Do you mix with powder? Mix with aqueous solution? And so on.
As a flame retardant that is highly effective for cellulose, couldn’t it be expected to be effective for cellulose nanofibers?