Fast Curing of Composite Wood Products

Fast Curing of Composite Wood Products Program Review by A.J. Ragauskas

Research Team Institute of Paper Science and Technology Georgia Institute of Technology Art J. Ragauskas, Associate Professor Chemistry Dong Ho Kim, Post Doctoral Research Fellow Jason Montegna, MS student Auburn University School of Forestry Thomas Elder, Professor of Forestry Utilization of Southern Forest Products, USDA-Forest Service Southern Research Station, Pineville, LA

Industrial Partners Georgia-Pacific Resins, Inc. -Resins, press time, & technical expertise Decatur, GA Georgia-Pacific Building Products Louisiana-Pacific Corporation -Wood chips, technical Sherwood, OR expertise

Weyerhaeuser OSB Business Tacoma, WA -Wood chips & technical expertise

Project Objectives Develop low temperature curing technologies for composite wood products manufactured with UF and PF resins by: •

Identifying rate limiting UF and PF curing reactions with current market resins.

•

Examining the use of new catalysts to accelerate curing reactions to reduced press temperatures and times.

•

Improve Board Properties.

U.S. Technology Market • 20 MDF mills • 41 OSB mills • 48 PB mills 1. Debarking 2. Mechanically refined wood 3. Drying 3’. Resins/mat formation/pressing

Project Deliverables • Characterize SW and HW woodchips • Prepare OSB, MDF, and PB • Characterize boards for physical strength properties & curing chemistry • NMR & DSC • Evaluate impact of extractives on composite board properties • Evaluate curing chemistry of PF and UF for composite board • Examine impact of plate pressure & temperature on curing resin chemistry • Design & evaluate effect of curing catalyst for composite board formation

Program Deliverables • Evaluate pretreatments to mitigate detrimental wood extractives effects • Test catalyst curing technology • Employ catalyst to lower curing temperature • Characterize board properties and chemistry with new catalyst • Perform energy audit for new catalyzed composite board formation process • Final report

Characterize Woodchips/Resins Commercial OSB Wood Strands % Extractives

% Moisture Content

Pine

4.2%

4.0%

Aspen

4.4%

3.7%

Hardwood

4.4%

7.1%

Strand Dimensions: (0.5-0.7mm) x (20-30mm) x (20-40mm) Resins*:

UF

PF-3110

PF-3121

pH

7.5

11.0

9.7

Solids Content

64.4%

46.2%

58.8% * Commercial resins

Evaluate Curing Chemistry PF and UF Gel Time Experiment • ASTM: D 3056-00 • 100.0oC • Insert sample into sample vial •Rapidly add catalyst • Begin stirring • Allow test specimen to remain in bath till stirring stops

Evaluate Curing Chemistry PF and UF

40

Gel Time (min)

35 30 25 20 15 10 5 0

UF Resin

PF: 3121

PF: 3110

Evaluate Curing Chemistry PF and UF O O

O

40 35

O Gel time (min)

30

H

25

O Me

20

O

O

15 Control

10

O

O

tetraethylenepentamine

O

10% Triacetin

5

10% Propylene Carbonate

0 UF Resin

O

10% Methyl Formate PF: 3121

PF: 3110

HN

N

NH2 2

Gel Times (min)


40 35 30 25 20 15 10 5 0

Control 5% Additive 1 10% Additive 1

UF PF: Resin 3121

15% Additive 1

PF: 3110


Gel time (min.)

35 30 25 20 15 10 5 0 C

ro t on

1% 0.

l

di d A

e tiv

5% . 0

2 d d A

e ti iv

0% . 1

PF:3121 PF:3110 UF

2 d d A

e ti iv

2

0% . 5

d Ad

e itiv

2

Evaluate Curing Chemistry UF: Binary Effects

40

Gel Time (min)

35 30 25 20 15 10 5 0 Control

1% Methyl Formate

10% Additive 1

1% MeF + 10% Add. 1

Evaluate Curing Chemistry PF: Binary Effects 35

Gel Time (min)

30 25 20 15 10 5 PF:3121

0 Co ntro l

1% P ro pylene Carbo nate 10% A dditive 1

PF3110 10% A dd. 1+ 1% P ro pyl.

Evaluation of Additive 1 For OSB Production Preliminary Studies

OSB Production: Experimental Procedure •Wood strands were weighed to yield final board densities of approximately 0.62 gr/cm3. •The PF and UF resins/additives applied onto wood strands via air sprayer unit •Blended furnish was then hand felted into a form box with aluminum cauls. •Mat consolidation and curing were accomplished using a laboratory hydraulic press (Carver press, 6” x 6”). •PF resins treated strands were cured at a press temperature of 350oF with 2.8 Mpa pressure for 3 minutes. •UF treated strands were treated in a comparable method except the press temperature was 300oF.

OSB Production: Experimental Procedure After board formation •All boards were conditioned at 20oC and 50% humidity for 72 hrs.

Thickness swelling and water adsorption were measured according to ASTM D1037 and DIN52364. The specimens were soaked in deionized water at 20oC. After 2 hrs, the specimens were withdrawn from the water and wiped with a paper towel to remove excess water. Increases in weight and thickness during the immersion were calculated on a mass basis and expressed as percentage.

OSB Laboratory Results 160 140

% increase

120 100 80 60 40 20 0 )

% % (5 (5 0 I 1 e 31 i tiv PF d d )/A % (5 0 11 3 PF

t. Wa ter A bso rp elling Thic kne ss Sw

) ) ) 5% % ( 5 1 1( 12 e 3 v ti PF di d )/A % 5 1( 2 31 PF

U

5% F(

% (5 F U

)

e itiv d d )/A

5% 1(

)

Preparation and Evaluation of Control and Additive OSB Production Follow-Up Studies

OSB Follow-Up Studies: Pilot Plant OSB Strands: Mat Dimension: Mat Formation: Target Density: Resin Content: Wax Content: Resin: Blend Moisture Content:

2.1kg per a board 40.6 x 40.6 x 2.9 cm One layer with random orientation 0.688 gr/cm3 3.5%(based on OD wt of strands) 1% on oven dry wood PF3110 7.0-7.5%

Press temp: Press pressure: - recommended by GP

400oF 95, 120 tons

OSB Follow-Up Studies: Pilot Plant Thickness Sw elling: 2h

20

Water Absorption: 2h

18

% Change

16 14 12 10 8 6 4 2 0

Wa te rA b so rp o ti n :2 h

T h ci k n e sS w e n il g :2 h

0.5% Additive 2, 5% additive 2, 120 tons

1.5% Additive 2, 120 tons

50

0.5% Additive 2, 120tons

Control, 120tons

5% Additive 1, 95tons



Control, 95tons

% Increase

OSB Follow-Up Studies: Pilot Plant 60 Thickness Sw elling: 24 h

Water Absorption: 24h

40

30

20

10

0

T h ci W

k a

n e t

e rA

sS b

w so

e rp

n il o ti

g n

:2 :2

4 4

h h

OSB Follow-Up Studies: Pilot Plant OSB Board

IB Density/(kg/m3)

IB/psi

Control 4.50 min, 95 ton

705

36.9

4.75 min, 95 ton

692

37.8

Additive 1 1%

4.50 min, 95 ton

712

54.1

2%

4.50 min, 95 ton

700

45.3

4.75min, 95 ton

722

42.5

4.50 min, 95 ton

707

39.2

5%

OSB Follow-Up Studies: Pilot Plant OSB Board

IB Density/(kg/m3)

IB/psi

Control 4.75 min, 120 ton

734

40.0

5.00 min, 120 ton

705

42.9

Additive 2 0.5%

4.75 min, 120 ton

689

43.1

1.0%

4.50 min, 120 ton

709

45.3

NMR Studies: PF and UF Curing OH

OH

PF resin Chemistry

OH

CH2

CH2

O

OH

OH HOH2C H2CO

CH2OH Heat Water Released CH2OH

Phenol

CH2

CH2

CH2

O

O

O

CH2

CH2

CH2

OH

OH

OH

CH2

CH2

UF Curing Chemistry O

O

O

H 2CO H 2N

NH2 Urea

H 2N

HO

H 2CO

OH NH

OH HN

Monomethylol Urea

Dimethylol Urea O

HO

O

NH

NH

N

NH

N

NH

H2C HO

NH

H 2C

O

N

NH O

Heat Loss of Water

NMR Studies: PF and UF Curing C2-6

-CH2C2-6 downfield sidebands

-CH2-OC1=O

-COx

C2-6 upfield sidebands

Solid state CP/MAS 13C NMR spectrum of PF 3110 resin as curing of 64 minutes.

NMR Studies: PF and UF Curing

Mol Ratio

3.0

F/P -CH2-/ P CH2-O / P

2.0

1.0

0.0 0

20

40

60

80

100

120

140

Curing Time, min

The mol ratio of methylene C to phenol C of the resin PF 3110. –CH2-/P: ratio of methylene/phenol; CH2-O /P : ratio of oxygenated methylene /phenol

NMR Studies: PF and UF Curing F/P -CH2-/ P CH2-O / P

Mol Ratio

3.0

2.0

1.0

0.0 0

20

40

60

80

100

120

140

Curing Time, min

The mol ratio of methylene C to phenol C of the resin PF 3121. –CH2-/P: ratio of methylene/phenol; CH2-O /P : ratio of oxygenated methylene /phenol

NMR Studies: PF and UF Curing Mol Ratio

3.0

2.0

F/U -CH2-/ U CH2-OH /U

1.0

0.0 0

20

40

60

80

100

120

140

Curing Time, min

The mol ratio of methylene C to urea C of the UF resin. –CH2-/U: ratio of methylene/urea; CH2-O /U : ratio of oxygenated methylene / urea; F/U: ratio of total methylene/ urea. Data indicated that the ratio of methylene and hydroxymethyl C/ urea C decreased as the curing proceeded.

Evaluate Impact of Extractives on Composite Board Properties

Evaluating Extractives: Exper. Procedure • Received industrial SW MDF, OSB, and PB furnish • Solvent extracted the wood furnish for 36 h • Used starting and extracted wood furnish for OSB, PB, and MDF • Tested for Physical Properties including: Thickness Swelling, Water Adsorption

Evaluating Extractives: Experimental Results 140 120

% Change

100 80 60 40 20 0

O

SB

F (P

O

0) 1 1 :3

SB

ex

es ti v c tra

e fre PB PB

(U

Water Absorption Thickness Sw elling

F)

e fre s e tiv c tra ex

DF M

F) (U

DF M

c ra t ex

es tiv

e fre

O

O

O

O

SB

SB

SB

SB

pr et rE

nz

y

y

y

y

nz

nz

nz

rE

rE

rE

et

et

et

pr

pr

pr

II

II

1

(5

(1

(5

(1

SB

1

O

U

/g

)

)

)

/g

/g

ro

)

nt

/g

U

U

U

co l

Enzyme Pretreatment: OSB Results 80

75

70

65

% 60

55

50

45

40

% TS % WA

D

F

F

D pr

et

et

pr r. E

zy

D F( co n tr o

m nz e 1 y m .. . e 1. ..

En

r. E

r.

et

et

pr

pr

M

nz r. . II E n (5 zy . m .. e II . .. P PB B( co p nt P B re t r ro . l* En pr ) et z r. I( En 0 z y . 1m PB I (0 l/ g .5 ) pr m e PB tr . l/g ) E pr nz et r. E n II (5 zI U / I( 50 g) U .. .

M

M

F

F

D

D l* )

% C hang e

M

M

Enzyme Pretreatment: Results 13 0 .0

12 0 .0 T S(%)

W A ( %)

110 .0

10 0 .0

9 0 .0

8 0 .0

70 .0

6 0 .0

50 .0

T S( %)

Nano Clay Studies

What is Nano??? What is Nano??? What is Nano??? What is Nano??? What is Nano?? What is Nano???

Nanotechnologies are characterized by structural elements in the nanometer range 1 m = 1000 mm = 1, 000, 000 µm = 1, 000, 000, 000 nm Sweet Spot Quantum Properties For Nano Technology

Newtonian Properties

Microchip 10 mm

Fiber

Hair

1 – 7 mm 50 µm

Cells 10 µm

Pentium III Chip 180 nm

DNA 2 nm

Atom 0.1 0.4 nm

Nano-Patenting Trends Patents containing nano 900

• Nano-patents in the exponential phase moving into application development and the second wave of patenting

800 700 600 Patents

500 400

• Commercialization potential is broad – multi facilitated field

Published • Patents may be only barrier Applic.

300

of entrance

200 100 0 1998

1999

2000

2001

2002

The Business Review – 2003 “Small is big and it's getting bigger”

Nano Clays for Barriers/Coatings • Pioneering work on nanoclay systems at Toyota's Research Center in Japan showed that a hybrid nylon nanocomposite has a HDT as high as 164°C that is 100°C higher than that of pure nylon 6. •Impact of differing alkylammonium nanoclays as fillers/coatings • Barrier • Printability

Polymer-Nanoclay Composites The thickness of nanoclay in the composite is about 1nm. Barrier coating for food containers and paper packages • Water and vapor resistance • Fatty and oil resistance • Paper-board strength

3.0

0.4

2.0 0.3 1.5 0.2 1.0 0.1

0.5 0.0

0.0 0

1

2

3

4

5

2

2.5

COBB Test (g/100 in. 2 h per unit loading)

0.5

2

2

WVTR x 10 (g/100 in 24 h per unit loading)

Polymer-Nanoclay Composites Paper Application

Nanoclay Content (wt %)

Relationship between barrier properties (WVTR and COBB) of waxed liner paper and nanoclay content. Wax used: Paraffin wax.

• 3% nanoclay in wax can increase water-barrier by 50%, and gas barrier by 100%, target for wax-coated paper container

Nano Clays and Effect on UF and PF Gel Times Employing 10% Charge of Filler Gel Time Experiment ASTM: D 3056-00 100.0oC • Insert sample into sample vial • Rapidly add catalyst • Begin stirring • Allow test specimen in bath till stirring stops

Experiment Control (no clay) Nanoclay NC-1 Nanoclay NC-2 Nanoclay NC-3 Nanoclay NC-4 Nanoclay NC-5 Nanoclay NC-6 Natural montmorillonite C-7

Gel Time UF PF 27.1 9.9 > 30 9.7 > 30 9.8 > 30 9.6 > 30 9.8 > 30 9.9 2.3 9.4 > 30 8.7

Nano Clays and Effect on UF Gel Times Employing Varying Charge of Filler Gel Time Experiment ASTM: D 3056-00 100.0oC • Insert sample into sample vial • Rapidly add catalyst • Begin stirring • Allow test specimen in bath till stirring stops

Experiment Control (no clay) Charge Nanoclay NC-6 2% 5% 10% 20%

UF Gel Time 27.1 4.8 3.1 2.3 1.6

Nano Clays and Effect on UF:Particle Board

• Wood furnish was blended with 1% of paraffin wax, hand felted into a form box • Mat consolidation and curing were accomplished using a laboratory hydraulic press 121o C • After hot-pressing boards were allowed to cool at room temperature, conditioned for 1 week • Thickness swelling and water adsorption were measured according to ASTM D1037

Nano Clays and Effect on UF:Particle Board 35

34

33

% Thickness Swelling

32

31

30

29

28

27

26

25 PB (Control)

PB + 5% Regular Clay

PB + 5% Nanoclay-101

PB + 5% Nanoclay-936



55

54

% Water Absorption

53

52

51

50

49

48

47

46 PF 300F-Control

PF 250F-Control

PB 5% Clay 300F

NC

PB 5% Clay 250F

NC



45

40


35

30

25

20

15

10

5

0 PF 300F-Control

PF 250F-Control

PB 5% Clay 300F

PB 5% Clay 250F

NC

NC

• Wood furnish was blended with 1% of paraffin wax, hand felted into a form box • Mat consolidation and curing were accomplished using a laboratory hydraulic press •After hot-pressing boards were allowed to cool at room temperature, conditioned for 1 week • Thickness swelling and water adsorption were measured according to ASTM D1037

PB – Additive: Thickness Swelling

Particle board - 2 Hour Thickness Swelling PB: Control

24

PB: 5% NC % Thickness Swelling

23

PB: 5% Zeolite PB: 5% CS

22 21 20 19 18

Lower Better!

17 16 200

250 Curing Temperature/F

Values for 2/24 h for water absorption and thickness swelling acquired

300

PB – Additive: Water Swelling

95

Particle board - 24 Hour Water Absorption

% Wtaer Absorption

90 85

PB: Control PB: 5% NC

80

PB: 5% Zeolite PB: 5% CS

75 70 65 60 200


300

OSB – Additive: Thickness Swelling

50

OSB - 2 Hour Thickness Swelling


45

OSB: Control OSB: 5% NC OSB: 5% Zeolite

40

OSB: 5% CS 35

30

25 200

250 Curing Temperature

375

OSB – Additive: Water Absorption

95

OSB - 24 Hour Water 90 OSB: Control

% Water Absorption

85

OSB: 5% NC 80

OSB: 5% Zeolite OSB: 5% CS

75 70 65 60 55 200


375

MDF – Additive: Thickness Swelling

10

FB - 2 Hour Thickness Swelling

9


8 7

FB: Control FB: 5% NC FB: 5% Zeolite

6

FB: 5% CS

5 4 3 2 1 0 200


375

MDF – Additive: Water Absorption

FB - 24 Hour Water Absorption 24

% Water Absorption

22 20

FB: Control FB: 5% NC

18

FB: 5% Zeolite FB: 5% CS

16 14 12 10 200


375

Additive Mixtures: OSB

5% Corn starch 90 80

2.5% Nano clay + 2.5% Cationic starch 2.5% Nano clay + 2.5% Zeolite

70

2.5% Zeolite + 2.5% Cationic starch % TS or WA

60 50 40 30 20 10 0 2hr

24hr Thickness sw elling(%)

2hr

24hr Water adsorption(%)

Additive Mixtures: MDF

5% Corn starch 40

2.5% Nano clay+ 2.5% Cationic starch 2.5% Nano clay + 2.5% Zeolite 35

2.5% Zeolite + 2.5% Cationic starch 30

% TS % WS

25

20

15

10

5

0 Thickness sw elling(%)

2h

Water adsorption(%)

24 h

2h

24 h

Additive Mixtures: PB

120

5% Corn starch 100

2.5% Nano clay + 2.5% Cationic starch 2.5% Nano clay + 2.5% Zeolite 2.5% Zeolite + 2.5% Cationic starch

% TS WS

80

60

40

20

0 2hr

24hr Thickness sw elling(%)

2hr

24hr Water adsorption(%)

OSB – Additive: IB Effect 80.0

OSB OSB 5% NC

70.0

OSB 5% CS OSB 5% Zeolite

IB/psi

60.0

50.0

40.0

30.0

20.0 T:200

T:250 Curing Temperature/F

T:350

MDF – Additive: IB Effect

75.0 70.0

FB FB 5% NC

65.0

IB/PSI

60.0

FB 5% CS FB 5% Zeolite

55.0 50.0 45.0 40.0 35.0 30.0 T:200

T:250 Curing Temperature/F

T:300

Key IB Effect Internal Bond Strength (kPa) Properties of Particle Board PB5%Nanoclay

PB-5% Zeolite

PB-5% Cationic Starch

200

38%

42%

44%

250

31%

--

28%

300

9%

7%

12%

Press Temp/oF

Conclusions • First demonstration that nanoclays can enhance UF gelling times and water stability properties of UF particle board • Provides benefits not available with routine clays • Mechanism and full benefits demonstrated for – – – –

Curing Energy Strength Properties Moisture stability Reduced charge

• Dependence on nanoclay structure unknown

Projected Benefits • New catalysts technologies developed for resin curing reduce energy curing costs by >15% • Detrimental effects of extractives on physical properties is significantly reduced • Reduced Emissions • Enhanced UF and PF resin chemistry is developed providing manufacturers improved product performance

IPST Member Companies U.S. Department of Energy [email protected]