Natural adhesives in thewood industry

Dr. Ing. Bruno Gorrini

Montevideo, September 11, 2018

CAETS 2018

Wood based adhesives: Today

• Petroleum based polymers

• The panel industry, is the larger user of products based on formaldehyde

• More than 50% of the formaldehyde produced in the world is used for the resin production and about 90 % of these resins are used in the production of wood based panels

Petroleum – based polymers

• Good Properties

• Inexpensive

• Limited resource

• Non –renewable

• Environmental/healthissues

Formaldehyde Wood based Adhesives

Formaldehyde Emissions

• 2004 IARC classifies formaldehyde carcinogenic

• June 10, 2013 EPA implements national formaldehyde emissionsstandars (USA)

Formaldehyde emission from Particle boards in Europe

E3

E2

E1

Formaldehyde emission from Particleboards in Chile

30

20

10

6.5 6.5

4

PB MG HCHO / 100 GR

Pe

rfo

rato

rV

alu

e[m

g/1

00

gr]

1962 - 1980 1980 1995 2005 2012 2012 USA

Redrawn from Ramirez E., Biocomp, 2017

Global Trend of Product Emissions Standards

Harmon D., 9th European Wood-based Panel Symposium, 2014

Influence of the Emissions Levels in PB Production

Approaches for emission reduction by adhesives

• Control of synthesis and formulations• Lowering Formaldehyde/urea Molar Ratio• Scavengers ( urea solution or dry urea)• Formaldehyde catchers ( low molar ratio resins)• Introduction of crosslinkers (melamine) • Post treatments ( Ammonia solutions, etc.)

UF and MF adhesives

Approaches for emission reduction by adhesives

• Phenol- formaldehyde resins✓ Provides emissions down to Ultra Low emitting formaldehyde level ( ULEF)

• PF Modification (soy)✓ Provides emissions down to Ultra Low emitting formaldehyde level ( ULEF)

• Introduction of Non added formaldehyde adhesives ( pMDI)✓ Adhesive itself has not emitable formaldehyde✓ Emission of the board Will depend on emission potential of Wood substrate

Challengue for the Wood Industry

• Increased pressure to be sustainableForest Stewardship Council (FSC)

• Environmental Product DeclarationsLife –cycle enviromental impact of products

• Building Rating Schemeso Credits for renewable energy, efficiency , sustainabilityo Material & products play a important role

Natural Adhesives: Challengue and Oportunity

• Biobased Wood adhesives with the same bonding performance and samecost or lower than syntetic adhesives (UF or PF adhesives)

• Sustainable adhesives should not only be available at low costs, but also need to be easily distributable, fast reacting, and have a long pot life.

• Key factor is to achieve the same production speed ( press factor)

▪ Recent government legislative changes to minimize the health effects relating to product emissions of volatile organic chemicals (VOCs), most notably formaldehyde

▪ The use of renewable materials as a cost effective replacement for petrochemical components of adhesives.

▪ Price volatility of petroleum based adhesives

▪ There are some organizations that believe that any formaldehyde is unacceptable

Key drivers for the use of Bioadhesives

Volatility Price : Methanol Contract Prices

Volatility Price : Phenol Contract Prices 2001-2018 U

S$/t

on

US GOLF ICIS lor average Price

Biobased Polymers

Bio-based polymers are materials which are produced from renewable resources

Starch , Protein, Lignin, Tannin, etc..

+ Renewable

+ Environment Friendly ( reduced CO2 emissions)

Biobased Polymers

Disadvantages

• Availability

• Properties

• Uncertainties about health and safety

• Maturity

Natural Wood Adhesives

Saccharide based

Starch

Cellulose

Hemicellulose

Protein based

Animal Glue

Casein

Soy Protein

Aromatic Based

Lignin

Tannin

Oil based

Castor oil

Canola oil

Others

Natural Rubber

Liquefied Wood

Comparison of different Natural adhesives for Wood panel industry

Hemmila V. et al; RSC Adv., 2017, 7, 38604–38630

Tannin based adhesives

• Plant-derived extractives , typically obtained from bark

• Natural polymeric polyphenol very reactive

• Reaction is 10-50x faster than phenol (with formaldehyde)

• Potential to replace phenol

Industrial trial using tannin based adhesive in Plywood

Blending After prepress After Press Knife test

60% of Phenol replacement for radiata pine tannin

Extruder Blender using Tannin based Adhesive

2.2 mm radiata Pine Veneer

Resin stability for Plywood ProductionV

isco

sity

[cp

s]

Standard PF Resin

60% Tannin Resin

Days

Ready to use adhesive

Wo

od

Fai

lure

[%]

Standard PhenolicResin

Resin with 60% Tannin

Industrial Trial Results.60% Phenol replacement for Tannin

• 176 gr/m2 extruder blender• 60 ton of resin trial• 18 mm board

Use of Lignin

• Lignin is Nature´s second most abundant biopolymer

• Natural phenolic compound

• Major by- product of chemical pulping

• The Brown gold of bioeconomy era

• Lignin Price between 350-600 US$/ton (Phenol :1300 US$/ton]

15-31% lignin content in the wood

Use of Lignin

Lignin are underutilized:• Low chemical reactivity• Heterogeneous structure• Diverse chemicals compositions• Isolation Processes ( Kraft, organosolv,sulfite,

soda and enzymatic hydrolisis)

Lignin Modifications to improve Reactivity• Methylolation of lignin• Liqueafaction of ligninbark in phenol

(phenolation)

Lignin Structural Units

Lignin which have very high hydroxyl-phenyl (H-lignin) content are the best candidates to replace 100% of phenol in phenolic adhesive formulations

Nejad, ICWPT 2017

Potential of 100% Phenol Replacement for Lignin

Laboratory Results

(): Standard Deviation

Example of Industrial Production based on Lignin

UPM BioPiva™ lignin product 50% phenol replacement

Obtained from Sanna Valkonen, UPM Biochemicals, 11th International Conference on Wood Adhesives, 2017

Other Natural adhesives

LigateTM adhesive

• Developed by Scion ( New Zealand)

• Totally biobased and using renewable materials ( Tannins- Lignin- Agri-Proteins)

• Adresssing indoor quality , Sustainability, Green chemistry drivers

• Suitable for Plywood, MDF, Particleboard , cross laminated lumber

Protein based Adhesives

• Soy protein as an adhesive to manufacture wood products has seen a huge resurgence

• The soy protein is derived from the residual soy mealremaining after the removal of the oil

• Comercial technologies are available:• Soyad® : soy protein + cross-link with Aminopolyamide-epiclorohydrin (PAE)• SOYBABY* - OZERO* - (MDF-HDF-Laminated floor)

PAE Resin – Soy Chemistry

Allen, 2009, Lake Tahoe, Wood Adhesive Conference

NATURAL ADHESIVE PRODUCTION & NAF

Soy, 72%

Tannin, 165%

0%

20%

40%

60%

80%

100%

120%

140%

160%

180%

NAF Alternatives

Co

st In

cre

ase

Estimated Cost Increasing, using NAF adhesives [MDF and PB]

Cost Limit

MDI; 15%Redrawn from Ramirez E., Biocomp, 2017

• Synthetic resins are coming under increasing restrictions due environmentalexposure regulations

• Bio-adhesives can now be used as natural, suistainable options to traditionalsynthetic adhesives

• High costs are a significant barrier to the development of bioresins

• Improvement in the performance of bio-adhesives is a key focus for existingresearch

• The future will be an environmentally friendly bioadhesive based on natural and renewable resources and produced under sustainable conditions

Conclusions

Still many creative ideas are required for industrial application of Natural Adhesives

FORMALDEHYDE CASUALDEHYDE

¡¡¡¡ THANK YOU !!!!