Exolit® for

Exolit® for
Thermosets

Exolit for
Thermosets
Contents
Exolit for thermoset resins 4
Unsaturated polyester resins (UP resins) 6
Epoxy resins (EP resins) 11
Polyurethane and phenolic resins 14
2
Exolit for Thermosets

3
Clariant offers a range of
non-halogenated flame
retardants for thermosets
under the trade name Exolit.

Exolit for
thermoset resins
Clariant offers a range of non-halogenated flame retardants
for thermosets under the trade name Exolit with the following
characteristics:
In case of fire
· Low smoke gas corrosivity resulting in less damage to
installations and buildings
· Low smoke density, meaning better visibility for an
extended escape time
In the final product
· High effectiveness of flame retardants resulting in a
low impact on mechanical properties
· Excellent UV stability and suitability for outdoor applications
· Good electrical properties for applications in the
Electric and Electronics (E & E) industry
· Good recyclability and low impact on carbon footprint
· Attractive price / performance ratio resulting in a
competitive system
Under the brand name Exolit, Clariant supplies non-halogenated
flame retardants with a good environmental and health profile for
thermoset resin systems.
Their advantage lies in their effectiveness, which enables very
low concentrations to be used, while at the same time meeting the
most stringent flammability requirements. As a result, favorable
processing properties are imparted accompanied by low specific
weight and excellent mechanical values of the finished articles.
If Exolit containing systems do catch fire, less smoke will be
released. Since these flame retardants are non-halogenated, no
corrosive fumes such as hydrochloric acid (HCl) or hydrobromic
acid (HBr) are given off. These properties are of great importance
in modern vehicle manufacture and are also important for the
new European regulation for railway rolling stock EN 45545-2.
Table 1: Different flame test requirements and regulations in certain application areas
Application Area Pictogram Test Country Description Classifications
Construction and building DIN 4102 part 1 Germany Chimney test and small burner test B1; B2
NF P 92-501 France Epiradiateur M1 > M2 > M3
BS 476 UK Surface spread of flame 1 > 2 > 3
ASTM E 84 USA Steiner tunnel Flame spread & smoke density
Transportation – Railway DIN 5510 Germany Fire behaviour and side effects S, SR, ST
DIN EN 45545 EU Smoke density HL3 > HL2 > HL1
Smoke toxicity
HL3 > HL2 > HL1
Spread of flame
HL3 > HL2 > HL1
Cone calorimeter test
HL3 > HL2 > HL1
NF P 92-501 France Epiradiateur M.1, M.2, M.3
ASTM E 162 USA Surface flammability A > B > C
ASTM E 662 USA Smoke box Smoke density (Ds) value
Transportation – Aviation FAR 25.853 USA Smoke density yes/no
ABD 0031 Airbus Smoke density & toxicity CO; HCN; NO x ; HCl; HF; SO 2
Electrical engineering UL 94 International Flammability test 5V; V-0 > V-1 > V-2; HB
4
Exolit for Thermosets

The required addition rate of Exolit flame retardants reflects the resin,
fibre type and processing conditions of the thermoset resin composite.
Table 2 gives an overview of possible Exolit flame retardants in different
resin systems.
Table 2: Thermoset product overview
Exolit type Description Supply form
D50 [μm]
Decomposition
temperature
UP resin
gel coat
EP resin
PU casting
Phenolic
resins
AP 422 Standard product, ammonium polyphosphate White powder approx. 15 > 275 °C n n n n n
AP 423 Fine grade, ammonium polyphosphate White powder approx. 8 > 275 °C n n n n
AP 462 Microencapsulated for moisture sensitive applications White powder approx. 20 > 275 °C n n n n
AP 740 Intumescent system White powder approx. 16 > 200 °C n n n
AP 740 S Intumescent system, for moisture sensitive application White powder approx. 16 > 200 °C n n
AP 740 F Intumescent system, fine grade White powder approx. 10 > 200 °C n n
AP 742 Intumescent system, for lower viscositiy applications White powder approx. 16 > 200 °C n n n
AP 750 Intumescent flame retardant system White powder approx. 16 > 250 °C n n
AP 755 Intumescent flame retardant system White powder approx. 12 > 275 °C n
OP 550 Reactive phosphorus polyol Medium-viscosity liquid – > 150 °C n n
OP 560 Reactive phosphorus polyol Medium-viscosity liquid – > 150 °C n
OP 930 Fine grade, phosphinate White powder approx. 3 > 300 °C n
OP 935 Extra fine grade, phosphinate White powder approx. 2 > 300 °C n
RP 6500 Red phosphorus in carrier: epoxy resin Red thixotropic dispersion approx. 24* > 200 °C (Epoxy resin) n
RP 6520 Red phosphorus in carrier: castor oil Red thixotropic dispersion approx. 24* > 350 °C (Castor oil) n
* Red phosphorus
5

Unsaturated polyester resins
(UP resins)
Lightweight constructions
with Exolit
Fiberglass reinforced composites play an important part in construction,
transportation, tanks, pipes and electrical components.
These composites can be manufactured by Sheet Moulding
Compound (SMC)/Bulk Moulding Compound (BMC), Resin
Transfer Moulding (RTM) processing or open mold techniques.
Unsaturated polyester resins are important for those applications.
Very often these composites have to fulfill stringent fire and
safety regulations, necessitating the use of flame retardants.
To meet these requirements, the use of halogenated UP resins
(frequently combined with antimony trioxide as synergist) and
aluminium trihydroxide (ATH, flame retardant filler) has become
standard practice in recent years. But ATH in particular is likely
to bring an increase in viscosity (owing to higher filler levels to
reach the required fire retardation) and higher densities of the
components. Moreover, halogenated flame retardants have come
under public and legislative pressure because of widespread findings
in the environment, toxic effects and the potential formation
of halogenated dioxins by uncontrolled combustion [ lit.: Beard A.,
Angeler D. (2010): Flame Retardants: Chemistry, Applications,
and Environmental Impacts. Wiley-VCH, Weinheim. Wiley-VCH.
pp. 415-439. ]
The Exolit grades offer major advantages especially in construction
and rolling stock applications. By combining the Exolit products
with aluminium trihydroxide stringent flammability requirements
can be met even with low filler levels. In addition, Exolit grades can
be used to formulate intumescent (gel)-coats which drastically
improve the fire endurance of the whole composite part. Clariant
is a world wide leader in the manufacturing of ammonium polyphosphate,
one of the key raw materials for the formulation of
intumescent (gel)-coatings.
In addition to the traditional hand lay-up process, the Exolit
flame retardants can be used in pultrusion and other advanced
techniques.
Advantages of systems with Exolit:
· Low density of the components
· Low processing viscosity
· High glass contents are possible
· Halogen free hand lay-up formulations are possible
· Pultrusion and advanced composite techniques possible
· Low smoke density, no corrosive combustion gases
Figure 1: Formulation examples with Exolit AP 740 and AP 422
for different flame tests
250
Picture 1:
Intumescent gel-coating
after flammability test
200
FR content [phr]
150
100
50
0
BS 476 NF P 92 501 EN 45545 DIN 5510
part 2
UL 94
n Exolit AP 750 n Exolit AP 422 n ATH
6
Exolit for Thermosets

Table 3: Guiding formulations for UP composites under various
processing methods
Classification Product Loading [phr] Processing
Construction
BS 476 Class 1
Class 1
Exolit AP 740 100 Gelcoat
BS 476 Exolit AP 740 50 Gelcoat
Class 1 ATH 50 Laminate
NF P 92 501 Epiradiateur Exolit AP 422 25
Class M2; 3 mm ATH 200
Laminate
DIN 4102 part 1
Class B1; 4 mm
Exolit AP 740 > 75 Pultrusion
DIN 4102 part 1
Class B1; 4 mm
Exolit AP 740 150 Gelcoat
Additional comments:
Exolit AP 422 can be replaced with an equivalent quantity of
either Exolit AP 423 (fine grade material) or Exolit AP 462
(reduced water solubility) as required. The Exolit AP range can
be used in combination with ATH in many halogen free thermoset
systems. Exolit AP 740 and Exolit AP 742 are special combinations
of ammonium polyphosphate with synergistic co-flame retardants.
These products offer improved intumescent effects that are
advantageous if a ready to use formulation is needed.
Transport
EN 45545; R1
HL 2
Exolit AP 740 125 Laminate
EN 45545; R1 Exolit AP 740 100 Gelcoat
HL 3 ATH 125 Laminate
DIN 5510 Exolit AP 422 2 – 5
S3, SR2, ST2; 4 mm ATH 20 – 40
Laminate
DIN 5510 Exolit AP 422 10 – 12
S4, SR2, ST2; 3 mm ATH 50 – 60
Laminate
ASTM 162 Class A
ASTM 662 DS 4 min 60
Exolit AP 740 100 Pultrusion
ASTM 662 DS 4 min 25 Exolit AP 423 25
ATH 200
Pultrusion
E&E
UL 94 Exolit AP 422 15 – 25
Laminate
V-0; 1.6 mm ATH 50 – 100
UL 94
Exolit AP 740 20 – 50 Laminate
V-0; 1.6 mm
7

New standard for railway rolling stock
EN 45545-2 FIRE AND
SMOKE REQUIREMENTS
EN 45545-2: 2013 Requirements for fire behavior of materials and components
In the past, each European country had its own fire protection regulations.
The country specific, local regulations for the fire protection on railway
vehicles are now replaced by a harmonized standard, EN 45545-2.
With this new regulation the testing was homologized and becomes much
easier. The different components of a train interior are now grouped
in R-classes (R1 – R26) and in each R class three different hazard levels
(HL1, 2 and 3) are defined. The measured values for smoke density,
smoke toxicity, spread of flame and cone calorimetry of the sample
(belonging to an R class) define the HL where the product can be used.
These new requirements under EN 45545-2 can be reached with
Exolit flame retardants.
Picture 2:
Fire protected modern
railway interior
8
Exolit for Thermosets

Table 4: Definition of R classes and required test values under DIN EN 45545-2:2013-08
Requirement
set
Materials
ISO 5658-2 (Spread of flame)
R1
Interior components: e. g. horizontal downwards and upwards facing surface; kitchen
interiors (except those of kitchen equipment); windows; interior surfaces of gangways
Type A; sound and termal insulation walls; air and cable ducts, electrical boxes
R2
Interior components: e. g. limited surfaces, water and air container,
upward surface of tables
Test method
reference and
parameter unit
ISO 5658-2 / CFE
[kW/m 2 ]
ISO 5658-2 / CFE
[kW/m 2 ]
Hazard level
HL1 HL2 HL3
20 20 20
13 13 13
ISO 5659-2 25 und 50 kW/m 2 (Smoke density & toxicity)
R1, R2 Interior components: horizontal downwards, upwards facing surfaces, walls,
luggage storage areas, driver‘s desk, interior surface of gangways (Type A),
wondow frames, curtains and sunblind, folding tables downward surface and top,
exterior and interior air ducts, devices for passenger info, underside surface of
couchettes and beds, enclosures for electrical equipment, cable containment
for interior and exterior, limited surfaces, other surfaces of water/air container,
arc resitant insulation material (Type A/B), back shell of passenger seats
EN ISO 5659-2 /
50 kW/m 2 Ds(4)
EN ISO 5659-2 /
50 kW/m 2 VOF4
EN ISO 5659-2 /
50 kW/m 2 CIT
600 300 150
1200 600 300
1.2 0.9 0.75
ISO 5660-1 (Cone calorimeter test )
R1
Surfaces of walls, ceiling, tables; insulation materials, air and cable ducts, window
frames, luggage racks, pannelling of the driver‘s desk, downward surface of tables
ISO 5660-1 / 50 kW/m 2 - a) 90 60
R2 Water and air container, upward surface of tables, toilet wash basins and surrounds ISO 5660-1 / 50 kW/m 3 - a) - a) 90
a) If flaming droplets/particles are reported according clause 5.3.7 during the test ISO 5658-2, or for the special case of materials
which do not ignite in ISO 5658-2 and are additionally reported as unclassifiable, additional tests are required.
9

Unsaturated polyester resins
(UP resins)
Lightweight constructions
with Exolit FOR RAILWAY APPLICATIONS
Figure 2: Two UP composite formulations and corresponding hazard levels (for application R1)
Spread of flame 20
20
HL 1, 2 & 3
34
CFE
[kW/m 2 ]
HL3 HL2 HL1
Smoke density
150
300
300
DS(4)
147 212
HL3 HL2 HL1
Smoke density
300
600
1200
VOF4
87 167
HL3
HL2
HL1
Smoke toxicity
0.025 0.138
0.75
0.9
1.2
CIT
HL3
HL2
HL1
MAHRE
60
90
[kW/m 2 ]
55 76
Laminate with 125 phr Exolit AP 740
Laminate with 125 phr ATH + Gelcoat with 100 phr Exolit AP 740
The Exolit containing formulations achieve at least Hazard Level 2.
The application of a gelcoat with additional flame retardant on top
improves the raiting for smoke density and heat release (MAHRE)
from HL2 to HL3.
10
Exolit for Thermosets

Epoxy resins (EP resins)
Achieving high flame retardant
standards and excellent electrical
properties with Exolit
Due to the higher price and better performance epoxy resins are
used in demanding applications. These applications are often in
the E & E industry or construction where fire regulations are
mostly prescribed. Here it is necessary to use flame retardants. One
current practice is to use brominated EP resins based on tetrabromo
bisphenol A. In the event of fire corrosive smoke gases occur, due
especially to the halogen compounds. Another common solution
is the use of high levels of ATH which negatively impacts the
mechanical performance of epoxy based composites. Exolit flame
retardants for EP resins allow substitution of bromine flame
retardants or a significant reduction of filler content which
broadens the application spectra of the resins.
Figure 3: Different formulation examples for UL 94 test results in epoxy resin
systems, phr (= parts per hundred parts of resin) indicates amount of epoxy resin
without hardener
FR content [phr]
60
50
40
30
20
10
V0
V0
UL 94 ( 1.6 mm )
V0
V0
V1
Exolit AP types are designed for high requirements in composites
(e. g. rolling stock) whereas the Exolit OP powder types show
outstanding performance in epoxy laminates for the electronic
industry and are used in rigid and flexible copper clad laminates.
0
Aliphatic
amine
n Exolit AP 422
n Exolit AP 750
Aliphatic
amine
DICY DICY Phenolic
hardener
n Exolit OP 935
n Melamin Cyanurate
n Exolit RP 6500
Picture 3:
UL 94 flammability test
Advantages of systems with Exolit:
· No corrosive smoke in case of fire
· Low smoke density
· Lower filler content, therefore lower processing viscosity
· Use of higher glass content possible
· Lower density of the components
11

Table 5: Different guiding formulations for epoxy resins, phr (= parts per hundred parts of resin) indicates amount of epoxy resin
without hardener
Classification Product Loading [phr] Processing Epoxy resin Hardener
E&E
UL 94
V-0; 1.6 mm
UL 94
V-0; 1.6 mm
UL 94
V-0; 1.6 mm
UL 94
V-0; 1.6 mm
UL 94
V-0; 1.6 mm
UL 94
V-1; 1.6 mm
Exolit AP 422 25 Laminate DGEBA Aliphatic amine
Exolit AP 750 50 Laminate DGEBA Aliphatic amine
Exolit OP 935 45 Laminate EPN Phenolic hardener
Exolit OP 935
Melamine cyanurate
21
21
Cured resin sample DGEBA DICY
Exolit OP 935 30 Cured resin sample DGEBA DICY
Exolit RP 6500 40 Cured resin sample EPN Phenolic hardener
Transport
DIN 5510
S4, SR2, ST2
Exolit AP 422 35 Laminate DGEBA Aliphatic polyamine
Construction coating
DIN 4102 part 8
F30/F60
Exolit AP 740 F 90 IC coating, DFT
2200 +/-200 µm
Waterborne solid
epoxy resin
Aliphatic amine
12
Exolit for Thermosets

Picture 4:
Steel construction with
intumescent coating
in airport terminal
Additional comments:
Exolit AP 422 can be replaced with an equivalent quantity of either
Exolit AP 423 (finer grade material) or Exolit AP 462 (reduced
water solubility) when required. Flame retardants of the Exolit AP
range are commonly used in combination with ATH in many thermoset
systems. Exolit AP 750 is a special combination of
ammonium polyphosphate with synergistic co-flame retardants.
The small particle size which is often required in the electronic
industry can be realized by the use of Exolit OP 930 and Exolit
OP 935. The addition rate to achieve a specific fire classification
heavily depends on the epoxy resin type and hardener (aliphatic /
aromatic) and on the glass content of the system.
13

Polyurethanes and phenolic resins
Enhanced flame retardant
performance and good processing
characteristics
PU casting resins are used largely as insulating materials in
electrical applications. Mineral fillers are often used to modify
the properties, e. g. to increase the hardness and rigidity of components,
to lower the coefficient of thermal expansion or to reduce
the shrinkage. To reach UL 94 classification V-0, which is usually
required in the electrical sector for components with high specific
requirements, large amounts of fillers which also have flame
retardant properties are added, e. g. ATH.
Adding Exolit AP 422, Exolit AP 462 or Exolit RP 6520 substantially
reduces the amount of ATH required to reach V-0 classification.
This makes it much easier to process the system and manufacture
the components. Exolit RP 6520 is a red phosphorus dispersion in
castor oil and avoids the handling of red phosphorus powder.
Figure 4 shows different Exolit formulations with reduced ATH
content which fulfill the UL 94 V-0 requirements.
Advantages of the system
· No corrosive smoke in case of fire
· Low smoke density
· Low filler content
· Low processing viscosities
Easier to process phenolic resins have been developed over the
last years and have broadened the application range. The flame
retardant performance of phenolic resins which are often chosen
by the (transportation) industry for its heat resistance and good
smoke density, toxicity and flame properties can be enhanced by
addition of Exolit flame retardants. Possible products are Exolit
AP 422, AP 423, AP 462 and Exolit OP 550. If necessary Exolit
AP 422 can be replaced with an equivalent quantity of either
Exolit AP 423 (finer grade material) or Exolit AP 462 (reduced
water solubility).
Figure 4: Flame retardant concentration in PU casting resins: Combinations of
Exolit with and without ATH
FR content [phr]
400
350
300
250
200
150
100
50
0
UL 94 ( 1.6 mm )
n Exolit AP 422 n Exolit RP 6520 n ATH
14
Exolit for Thermosets

15
Picture 5:
Printed circuit boards
(PCBs) are a major
application area
for flame retarded
epoxy resins.

Clariant International Ltd
Rothausstrasse 61
4132 Muttenz
Switzerland
Business Unit Additives
Business Line Flame Retardants
Phone + 41 (0) 61 469 78 50
Fax + 41 (0) 61 469 75 50
www.exolit.com
www.clariant.com
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DA 4003 E | 10.2013
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