A new green product for the cultural heritage conservation

Gianfreda B.1, Macchia A1., Rivaroli L1., Nunziante Cesaro S.2, La Russa M.F.3, Ruffolo S. A.3, Damiani F.1

1YOCOCU, Roma, Italy, info@yococu.com 2SMATCH, Rome, Italy, stella.nunziante@libero.it

3University of Calabria, Arcavacata di Rende (CS), Italy, mlarussa@unical.it

What is the problem?...... First: Cleaning, I suppose

The restorers have a solution: MEK o similar solvents

R.E.A.C.H. = Registration,Evaluation,Authorisation,of Chemicals

Green Chemistry R.E.A.C.H.

Review of M.S.D.S. ENVIRONMENT, WORKPLACE, IMPACT ON SAFETY for WORKERS

Is this applied in CH sector?

Aim

To set up a green product for the removal of old and modern varnishes

To transfer industrial products to cultural heritage field

Experimentation Survey of solvents: Easy to find on the market e.g. solvents used in drug, food and painting industries Low toxicity

Production of laboratory specimens to perform cleaning tests with 8 solvents

In situ tests on real case studies

Experimentation

8 solvents selected

*VARNISH REMOVAL FROM PAINTINGS USING IONIC LIQUIDS by Maria Filipa Pacheco and oth.-Departamento de Conservacao e Restauro,Universitade Nova de Lisboa, Portugal 2013)

Canvas (15x15 cm)

Red pigment + linseed oil

4 types of varnishes + black pigment (no IR)

DAMAR, RETOUCHER, PVA and PMMA*

Ageing : SUNTEST CPS + (168h and 336h)

Cleaning system: swab (Solvent: 2.5 ml )

Evaluation of cleaning efficacy (presence of residues): • Restorer’s observations • Micro FTIR • Spectrocolorimeter • UV/VIS imaging

Two paintings (18th-19th century)

Selection of Solvents

Easy to find on the market

Low toxicity - High LD50

High Boiling Point

Low Vapour Pressure

Low or No VOC

High Flash Point

No Mutagenicity ,Cancerogenicity

Selected solvents

C A S Name Chemical formula

109-87-5 Metilale C H3O C H2O C H3

108-32-7 Propil. carbonato 4 METHYL 1,3 DIOXOLAN-2-ONE

2568-90-3 Butilale C H3(C H2)3O C H2O (C H 2)3 C H3

109-99-9 T H F C4H8O /-CH2CH2OCH2CH2-\

646-06-0 Dioxolano 1,3 DIOXACYCLOPENTANE

67-64-1 Acetone ( C H 3 )2 C O

78-93-3 M E K C H3 C O C H2C H3

Physical properties NAME Density

g/lt

Boiling point°

C

Flash

Point ° C

Vapour

pressure Kpa

Methylal 0,86 42,3 - 30,5 40

Propil carbonate 1,205 242 123 0,05

Butylal 0,84 180 62 20

T H F 0,88 66 - 21,5 17

Dioxolane 1,06 76 2,5 10,1

Acetone 0,79 56 - 17 24

M E K 0,8 80 - 1 12,1

Green Rescue 1,04 140 91 4,2

Toxicological Characteristics Name LD50 mg/Kg @DNEL

mg/m3/gg VOC

Methylal 2000 130 100%

Propil carbonate 34900 80 No

Butylal 6500 130 No

T H F 1650 150 100%

Dioxolane 2000 50 100%

Acetone 5800 500 100%

M E K 3300 600 100%

Green Rescue 4300 800 No

@ D.N.E.L.(Derived No Effect Level = is an indicator for determining the hazardous effects upon human health of chemicals substances (is measured in mg and compared with cubic meter of work place during 8 ours. Evidently this value is easily and rapidly reached by volatile .see Tab.2

Ageing 168hr and 336hr Starting point Cleaning

Methylal Propil

carbonate Butylal

Green Rescue

T H F Dioxolane Acetone M E K

L* 40.340 40.517 41.319 40.172 40.307 40.691 39.562 40.267

a* 45.088 45.239 47.880 43.040 43.315 45.606 42.561 43.601

b* 25.775 25.328 27.779 23.685 24.068 26.013 24.119 24.406

c* 51.936 51.847 55.358 49.127 49.555 52.504 48.921 49.969

PARALOID

Red Oil painting Starting point

Ageing 168hr

L* 39.480 33.411 30.074

a* 42.415 28.844 12.148

b* 23.018 15.119 5.703

c* 48.517 32.572 13.421

During the cleaning, several surface measuring points were acquired by 3NH Technology -Spectrophotometer NS820.

PARALOID

RED Pigment + LINSEED OIL

MEK

GREEN RESCUE

paraloid

Methylal

D B E

Propil carbonate

Butylal

Green rescue T H F

Dioxolane

Acetone

M E K

damar

Methylal

D B E

Propil carbonate

Butylal

Green rescue T H F

Dioxolane

Acetone

M E K

retoucher

Methylal

D B E

Propil carbonate

Butylal

Green rescue T H F

Dioxolane

Acetone

M E K

PVA

Methylal

Propil carbonate

D B E

Butylal

Green rescue

T H F

Dioxolane

Acetone

M E K

Results

Retoucher P V A Damar Paraloid

Metilale ++ ++ + +++

D B E +++ ++ + ++++

Propil. Carbonato + + + +++

Butilale +++ ++ ++++ ++

Green Rescue ++++ ++++ ++ ++++

T H F +++ +++ +++ ++++

Dioxolano ++ ++ +++ ++++

Acetone ++ ++ + ++++

M E K +++ +++ +++ ++++

+ = low ++ = medium +++ = good ++++ = excellent

Green Rescue MEK

Green Rescue

MEK

Residues: UV control

MEK

Green Rescue

Omnia venenum sunt: nec sine veneno quicquam existit. Dosis sola facit, ut venenum non fit.

Conclusions