Bio-based Solutions for High-Performance Polyurethane Adhesives Angela Smits Bio-based Adhesives Conference 2013

Bio-based building blocks sustainable solutions

CRODA: Naturally derived speciality chemicals and sustainable products Global trend towards bio-based raw materials • Automotive: renewability targets, light weight design • Electronics: ‘green’ mobile phones, computers, gadgets • Sportswear: positive health and environment image • Packaging: improve carbon footprint

• Bio-based monomers: special dimer fatty acid, dimer diol, dimer diamine • Bio-based polyester polyols – up to 100% bio-based • Durability: impact modifiers for structural epoxies

Different forms of dimer fatty acids technology derived from natural oils

Dimer acid PRIPOL Dimer diol PRIPOL Dimer diamine PRIAMINE Polyesters polyols made with dimer acid (or dimer diol) PRIPLAST

HO---- ----- OH E--E

n

H2N NH2

OH OH

COOH COOH

Dimerised fatty acids technology Properties

Large hydrocarbon part (C36) • hydrophobic, water-repellent • hydrolytic resistance of derivatives • thermal resistance • affinity for low polarity matrices and surfaces • low Tg

Irregular non-crystalline structure • flexibility • good flow and wetting • low modulus, no strain hardening • no shrinkage

Di-functional constituent for • polyamides • polyesters • polyimides • polyurethanes, etc.

C=O

OH

O=C

HO

The PU adhesives in this study

• Polyurethanes from 1 single polyol; Priplast or conventional polyol • Reactive PU adhesives: prepared with excess solid MDI, moisture cured • PUD adhesives: prepared with IPDI, OH functional PU, tested without cross-linking

• Incorporating dimethyl propionic acid DMPA for water dispersion

Polyester polyol PUD particle size (nm)

Hexane diol adipate 18

Priplast 3192, semi-crystalline 45

Priplast 3293, semi-crystalline 100% bio-based 82

Priplast 3238, amorphous 100% bio-based 125

Flexibility of reactive polyurethanes flexible and no strain hardening

0

40

80

120

160

200

0 200 400 600 800Strain (%)

Priplast 3192semicrystallinePriplast 1838amorphousHDO-adipate

Mw of the polyols is 2000 NCO:OH = 2 Mechanical properties were measured after full cure

Modulus (kg/cm2)

-30

-20

-10

0

10

HDO-adipa

te

PTMEG

Priplas

t 319

2

Priplas

t 319

6

Priplas

t 183

8PPG

Priplas

t 183

8 (*)

Polyca

prolac

ton

Priplas

t 319

0

Recipe : 1 Polyol 2 Butanediol 3.1 MDI P1838 (*) = 1-1-2.1

Low Tg of polyurethanes flexibility also at low temperatures

Gla

ss tr

ansi

tion

tem

p. [o C

]

Adhesion to a variety of substrates PUD lap shear adhesion: good from smooth to fibrous substrates

0

0.5

1

1.5

2

Adh

esio

n (M

Pa)

HDO-adipate Priplast 3192 Priplast 3293 Priplast 3238

PUD was applied to both sides of the film, dried and re-activated at 70oC. A steel weight was used to join the two parts. Test on an Instron tensile tester.

0

2

4

6

Adhe

sion

(MPa

)

Priplast 3238 Priplast 3293

rigid PVC birch wood

Adhesion to a variety of substrates Reactive PU lap shear: High strength to hard, smooth plastics

Mw of the polyols is 2000 NCO:OH = 2

polyamide-6 polycarbonate

polystyrene PET film

NB = no break, slipped from the clamps SF = substrate failure

0

0.5

1

1.5

2

2.5

3

Adhe

sion

(M

Pa)

Priplast1838

Priplast3192

HDO-Adipate

PTMEG

0

0.5

1

1.5

2

2.5

3

Adhe

sion

(M

Pa)

Priplast1838

Priplast3192

HDO-Adipate

PTMEG

0

0.2

0.4

0.6

0.8

1

Adhe

sion

(M

Pa)

Priplast1838

Priplast3192

HDO-Adipate

PTMEG0

0.5

1

1.5

2

Adhe

sion

(M

Pa)

Priplast1838

Priplast3192

HDO-Adipate

PTMEG

SF SF SF SF

NB NB

Adhesion to hard, smooth substrates Reactive PU on polycarbonate – 100% bio-based Priplast

0

0.5

1

1.5

2

2.5

Adhe

sion

(MPa

)

HDO-Adipate

PPG PTMEG Priplast1838

Priplast3192

Priplast3238

Priplast3293

Priplast3286

Mw of the polyols is 2000 NCO:OH = 2 NB = no break, slipped from the clamps

NB

adhesives based on conventional polyols

NB NB

0

0.2

0.4

0.6

PEG PTMEG HDO-Adipate

Priplast3192

Priplast1838

Priplast3293

Priplast3286

Adhe

sion

(M

Pa)

Adhesion to low-energy substrates – untreated PE

adhesives based on conventional polyols

Mw of the polyols is 2000 NCO:OH = 2

Low moisture absorption of PU Priplast brings water resistance versus other polyols

0

0.4

0.8

1.2

1.6

2

Priplas

t 319

6

Priplas

t 183

8

Poly B

D

Priplas

t 319

0

HDO carbo

nate

Priplas

t 319

2

HDO-adipa

te

Polyca

prolac

tone

BDO-adipa

te

PTMEG

PPG

Moisture uptake at 23oC (%)

Recipe : 1 Polyol 2 Butane diol 3.1 MDI Conditions : 1 week in H2O dist.

Water resistance of PUD

• PUD without cross-linker • Priplast as good as cross-linked HDO-adipate (rating 3-4) • Adding 5% NCO cross-linker makes Priplast-based films nearly water resistant

• Spot test: water 16h – Rating 0 = very good, no mark; 5 = poor, damaged

Polyester polyol Water resistance

Hexane diol adipate 5

Priplast 3192 3

Priplast 3293 2

Priplast 3238 3

Durability: Thermo-oxidative stability of reactive PU based on Priplast

0%

20%

40%

60%

80%

100%

Rete

ntio

n of

pro

pert

ies

HDO-Adipate Priplast 3192 PPG PolyBD

Tensile strengthElongation

Cured polyurethane hot melt films Aged 4 weeks at 140oC Retention of mechanical properties

unsaturated diol; no ether / ester

Durability: Hydrolysis resistance PU aged in hot water – 100% bio-based Priplast

0

20

40

60

80

100

Priplast 3286 Priplast 3238 Priplast 3293 PTMEG HDO-adipate

Recipe : 1 Polyol 2 Butanediol 3.1 MDI Conditions : 1 week in H2O (dist.) at 90oC

Retention of tensile strength [%]

Summary of bio-based technology

Priplast dimer-based polyols: • Unique combination of hydrolytic and thermo-oxidative stability • Good mechanical properties: flexible, no strain hardening, low Tg

• Exceptional adhesion to a multitude of substrates • Excellent water resistance • High renewable content, up to 100%

• To protect substrates from moisture • To improve adhesion to low polarity substrates (plastics) • To adhere dissimilar materials • To obtain flexible adhesives

Thank you !

PU-dispersion basic recipe used, OH-terminated

• 100 g Priplast 3192, 13 g DMPA at 130°C / 25 mbar for 40 minutes • Break vacuum with N2, cool to 110°C, add 31g IPDI in 10 minutes, add acetone 35 g • Cool to 60°C and add 35 g acetone, stir until a clear solution is obtained • Cool to 50°C, react to NCO-number < 1 (theoretical OH-value 3.6) • Add 11 g TEA, stir for half an hour • Add 220 g water while intensively stirring, until phase inversion (CRITICAL step) • Then remove acetone at 50°C under gradually increased vacuum (to prevent

foaming), down to 100 mbar

• DMPA = dimethylol propionic acid; two OH-groups to build into the polyurethane, remaining carboxylic acid group to disperse into water