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Nat­ur­al sun pro­tec­tion for wood floors and furniture

03.05.2024

Wood, we come into close con­tact with it daily. Chil­dren play around on wood floors, and wood fur­niture plays an import­ant role in our work and sleep habits as well. To keep this nat­ur­al mater­i­al from aging pre­ma­turely, it’s import­ant to pro­tect it effect­ively against ultra­vi­olet (UV) radi­ation. At the same time, people want to retain the look and feel of nat­ur­al wooden sur­faces, but the trans­par­ent pro­tect­ive coat­ings that are cur­rently widely com­mer­cially avail­able often con­tain harm­ful chem­ic­al com­pounds. To avoid using these sub­stances, the Fraunhofer Insti­tute for Pro­cess Engin­eer­ing and Pack­aging IVV and Naturhaus Natur­farben GmbH are work­ing togeth­er to devel­op a for­mula that provides harm­less, trans­par­ent and 100 per­cent organ­ic UV pro­tec­tion for wood.

Open archi­tec­ture with glass facades and big win­dows that let nat­ur­al light flood into home interi­ors is very pop­u­lar — just like the desire for green liv­ing in har­mony with nature. When it comes to pro­tect­ing indoor wood sur­faces, how­ever, these two needs have been dif­fi­cult to bal­ance thus far. Without a coat­ing, UV light ran­ging from 330 to 380 nano­met­ers in wavelength can inter­act with wood sur­faces, caus­ing dis­col­or­a­tion and dam­age through a pro­cess known as pho­toox­id­a­tion. But the trans­par­ent pro­tect­ive coat­ings cur­rently avail­able on the mar­ket con­tain chem­ic­al addit­ives such as ben­zo­phen­ones, ben­zo­triazoles or phenyl­triazine deriv­at­ives, all of which are harm­ful to people’s health. One espe­cially crit­ic­al point is that these volat­ile sub­stances can enter the body dir­ectly via the res­pir­at­ory sys­tem, for example, dur­ing the dry­ing pro­cess. Thus far, all bio-based altern­at­ives to pro­tect wood against aging due to sun­light have been colored, so they are opaque. Pro­teins for bind­ing, plant extracts for UV pro­tec­tion

This led Fraunhofer IVV and Naturhaus Natur­farben GmbH to the idea of devel­op­ing a solu­tion for the issue. Tasked with find­ing suit­able plant-based com­pon­ents for a nat­ur­al wood fin­ish that would pro­tect the mater­i­al against UV radi­ation while still leav­ing the grain vis­ible, Fraunhofer IVV got to work on the ProTann pro­ject in 2021. The sci­ent­ists decided to explore a com­pletely new research field: ​“For nat­ur­al bind­ing in coat­ing sys­tems, we’ve had great suc­cess with using pro­teins at Fraunhofer IVV for quite some time now,” explains Melanie Platzer, a research sci­ent­ist in the Pro­cess Devel­op­ment for Plant Raw Mater­i­als depart­ment. ​“One thing that was new for us was com­bin­ing pro­teins with sec­ond­ary plant-based mater­i­als that serve as UV pro­tec­tion for a water-based fin­ish.” One of the project’s goals was to work out the cross-links cre­ated between the pro­teins and sec­ond­ary plant-based mater­i­als in the fin­ish and ulti­mately ensure that the sub­stances formed a per­man­ent bond.

A chal­len­ging devel­op­ment pro­cess

The pro­cess of devel­op­ing the fin­ish took place over sev­er­al stages. At first, the research­ers tested their ini­tial for­mu­la­tion idea, which built on a pre­vi­ous Fraunhofer IVV
pro­ject that used mul­tiple pro­teins, such as pea and soy pro­tein. Platzer com­ments: ​“We had a few cru­cial ques­tions dur­ing this phase. Does the coat­ing pro­duced adhere to wood? Does it absorb? And can it be removed so the UV-block­ing effect can be meas­ured in the first place?” Then the pro­ject team selec­ted two pro­teins and added vari­ous sec­ond­ary plant-based sub­stances that offer good pro­tec­tion against UV radi­ation. The pH presen­ted a chal­lenge, since wood fin­ishes have to fall with­in a cer­tain range so they do not harm the mater­i­al. Adding the plant extracts them­selves was also a cru­cial point for the research team, as it was dif­fi­cult to fore­see in advance how well the vari­ous extracts would dis­solve, wheth­er they would inter­act with the pro­teins, and how the col­or of the coat­ing cre­ated would change over the course of the pro­cess.

Which for­mu­la­tion is most suit­able?

Over the roughly two-year pro­ject term, the sci­ent­ists tested many com­bin­a­tions. They were also highly suc­cess­ful at work­ing with mix­tures of dif­fer­ent sec­ond­ary plant-based sub­stances. ​“In the end, we had a lot of good can­did­ates for pos­sible com­bin­a­tions of pro­teins and addit­ives for the UV pro­tect­ive coat­ing, so we were able to zero in on the ques­tion of which for­mu­la­tion makes the most sense in think­ing about pro­duc­tion — includ­ing with an eye to loc­al sourcing and avail­ab­il­ity of the raw mater­i­als used,” Platzer says. ​“Wherever pos­sible, we include residue from the agri­cul­ture and food industry in our devel­op­ment work. That includes things like peels left over from mak­ing apple juice, or pomace from wine pro­duc­tion.” The options iden­ti­fied are all harm­less, with no ill health effects on people or anim­als from dir­ect con­tact or breath­ing fumes.

Fur­ther devel­op­ment for pro­tect­ing wood and more

The mod­el for­mula selec­ted is now under­go­ing fur­ther devel­op­ment at Naturhaus Natur­farben GmbH. The goal is to adapt the com­pos­i­tion so it can be pro­duced on a
large scale, ulti­mately tap­ping into a new mar­ket in the nat­ur­al wood pre­ser­vat­ive seg­ment. The water-based for­mula could then be applied in sev­er­al coats, with a dif­fer­ent nat­ur­al fin­ish on top as a seal­ant, to provide last­ing pro­tec­tion for wood floors and fur­niture. To fur­ther devel­op the many research find­ings from ProTann and explore their poten­tial, Fraunhofer IVV has already ini­ti­ated a fol­low-up pro­ject. The UV-block­ing com­bin­a­tions of pro­teins and plant sub­stances could also be used to coat pack­ages or in skin­care, for example.

Source

Fraunhofer IVV

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