Carbodiimide Crosslinkers Presentation 2015

7/25/2019 Carbodiimide Crosslinkers Presentation 2015

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Polycarbodiimide crosslinkers

European Coatings Show, April 2015


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Introduction to crosslinking

Main types of crosslinkers: aziridines, isocyanates, polycarbodiimides

Crosslinkers comparison

Multifunctional polycarbodiimides Stahl Polymers polycarbodiimide range

Registration status

ips for application

Summary

Content


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!" systemsIn a #real !" system$ the binder is synthesized during application, by means of

a reaction bet%een a polyol and an isocyanate crosslinker& In this case, if

there is no crosslinker there is no binder&

Stahl Polymers binders are already polymerized and film forming& 'unction of

the crosslinker is to impro(e specific characteristics )mechanical properties,

chemical resistance,&&&*&

Polymer + crosslinker

Crosslinking


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ziridines

Isocyanates

Polycarbodiimides

-thers )melamines, epo.ies,&&&*

Types of crosslinkers


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ziridines are (ery effecti(e and allo% long pot li(es&&& but they are hazardous chemicals/

Aziridine

OHO

OHO

N N

N

N N

N

OO

OO

H

H

resincarboxylicacid residue

aziridinecrosslinker


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Isocyanate

HO

H2N

resinHydroxyl group

isocyanatecrosslinker

OCN NCO

OCN

amine groupN

O

H

H

N

NCONO

O

H

Isocyanates are (ersatile and effecti(e, but pot li(es are short due to their sensiti(ity to moisture&0ess se(ere labelling than aziridines&


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Polycarbodiimide (CDI)

Carbodiimide groups 123C324 react %ith carbo.ylic groups 1C--5 at room temperature&Polycarbodiimide crosslinkers are label4free and allo% to achie(e long pot li(es&

OHO

OHO

resincarboxylicacid residue

carbodiimide

crosslinker NCN

R N C N

NCN R'

NR

H

O

N

N

H

C

O

O

R'N C N

NC

O


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)6* 2ot all products ha(e all properties

Crosslinkers comparison

Polycarbodiimide * Isocyanate Aziridine

Reactivity -COOH -OH, -NH2, water -COOH

Pot life Up to weeks Up to 6 h 12 h

VOC (! " " - 2" "

#H$ sy%&ols 'o'e

R-phrases 'o'e R)*+2*+) ta. Cat ),

R22*)/*1*)*6/

oistrese'sitivity

low very hi0h hi0h

#as release 'o'e CO2 'o'e


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Stahl holds patents on multifunctional polycarbodiimides&

hese products contain a !nd reacti(e group that creates an e.tra crosslinking

net%ork and helps to achie(e e(en better performance&

Multifunctional CDIs


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Summary of Stal CDIs

Product Physical state Type Active

matter (%)

g/eq.

(on act. matter)

Picassia'-3"1 4li5 lii5 ltif'ctio'al +" +7"

Picassia' -3"2 4li5 lii5 8ater&or'e " +"

Picassia' -32+ Viscos lii5 ltif'ctio'al 1"" 3""

Picassia' -3)2 4li5 lii5 8ater&or'e " 6"


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!egistration status


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C7Is react %ith carbo.ylic groups& t p5 8.5 carboxylic groups are in the inert

carboxylate form, therefore: binder formulation at pH 8.5 LONG POT LIFE

Reaction takes place at room temperature

-nce the coating is applied, (olatile amines e(aporate, p5 drops and

crosslinking reaction starts

2nd reactive group of multifunctional CDIs is sensitive to water, in this case pot life is

up to 12 h. These products should be stored under protective atmosphere

-ptimum 8uantity of C7I must be found out through lab %ork, but it is usually 9

to ; on binder formulation

Crosslinking effecti(ity is e(aluated by means of chemical resistance test

Tips for application


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"#amples of application

!inder "#I "hemical $esistance

ithout "#I

$esistance

ith "#I

Picassia' 9C-126 6 Picassia'-3"1 :tha'ol / ) +

Relca H;-6" ) Picassia' -32+ :tha'ol / 1-2

Relca PU-33 2.+ Picassia' -32+


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Polycarbodiimides are a good alternati(e to isocyanate and aziridine crosslinkers

hey react %ith the carbo.ylic groups in the binder

Right combination #binder 1 C7I$ has to be found empirically )lab tests*

Carbodiimide Crosslinkers Presentation 2015

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