by | Sep 27, 2025
Technical Data Sheet
NOROX
MEC
Methyl ethyl ketone peroxide/Cyclohexanone Peroxide
CAS#1338-23-4
12262-58-7
Liquid mixture
Description
Norox MEC is a colorless solution of methyl ethyl ketone peroxide and
cyclohexanone peroxide in phlegmatizer. Norox MEC was developed to give
excellent cure performance in low and average temperature conditions when
used as an initiator with unsaturated polyester resins.
Technical Data
Active oxygen 9.0 max
Form: Liquid
Color: Water white
Specific Gravity @ 25 C: 1.12
Viscosity @ 25 C: 18.0 cps
Flash point (SETA C.C.) 170 F / 77 C, min
Soluble in: Oxygenated organic solvents
Slightly soluble in: Water
Maintenance of activity at 30 C as from date of
delivery
6 months
Application
Norox MEC should be considered for gel and cure initiation for cobalt
promoted unsaturated polyester resins at low operating temperatures.
Norox MEC will also give good performance at normal temperatures.
Other advantages, compared to standard MEKP formulations include:
1. Shorter gel to cure time in many resins.
2. Excellent smoothness and uniformity in the cure cycle.
3. Excellent storage stability because of the absence of
impurities (water, hydrogen peroxide, unreacted methyl ethyl
ketone and other diluents).
4. Enhanced performance with gel coats. (The hydrophobic
nature of Norox MEC provides improved mixing and resin
compatibility).
Technical Data Sheet
RESIN: Ortho Laminating (pre-promoted)
Initiator Gel Peak Gel to Barcol Hardness@
Time Exotherm Cure 3 hrs. 5hrs. 24 hrs.
Norox MEKP-9 15.9 min. 328 F 71 min. 5(4) 15(4) 34(4)
Norox MEKP-925 16.2 min. 336 F 76 min. 5(4) 7(4) 32(4)
Norox MEC 14.9 min. 330 F 61 min. 6(4) 16(4) 34(4)
Results determined by United SPI laboratory test methods and are to
be used for comparison, only.
Resin suppliers should be contacted for specific recommendations for
individual resins.
Resin: Typical ISO Marble Clear Gel Coat
Initiator Level: 2.0% Resin Temp: 77 F
Initiator Gel Peak Time to 20g Tack Barcol Hardness@
Time Temp Peak Peak Free 3hrs. 5hrs. 24hrs.
Norox MEKP-9H 13.8 min. 406 F 23.9 min. 344 F 79 min. 35(D) 55(5) 15(4)
Norox MEKP-925H 13.2 min. 423 F 24.0 min. 356 F 82 min. 15(5) 70(5) 20(4)
Norox MEC 11.6 min. 394 F 21.5 min. 358 F 75 min. 20(5) 60(5) 20(4)
Technical Data Sheet
PACKAGING, SHIPPING & AVAILABILITY
Technical Data Sheet
The standard package sizes of NOROX
MEC are 4×8 lb and 44 lb
(20 kg) polyethylene bottles.
NOROX
MEC is available pre-dyed in 44 lb (20kg) bottles. Please
see United Initiators, Inc. TDS for Peroxide Dye Concentrates.
Classification Please refer to the specific NOROX
MEC Safety
Data Sheet (SDS) under section 14 & 15, shipping & regulatory
information. NOTE: SDS s for all United Initiators, Inc. products may
be requested by contacting the company.
NOROX
MEC is available through a global network. Call United
Initiators, Inc. for the name of the distributor in your area
This information and our application-technical advice whether verbal, in writing or by way of trials reflect our present state of knowledge based on internal tests with local raw
materials. Their purpose is to inform interested parties about our products and their possible application. They should not be construed as guaranteeing specific product properties or
their suitability for a particular application. Furthermore, the information does not contain complete instructions for use. Nor does it constitute a guarantee as to quality and durability.
Changes due to technical progress and corporate advancement reserved. Any existing third-party copyrights are to be taken into account.
Application and use of our products based on our application-specific advice is beyond our control and sole responsibility of the user. The user is not released from the obligation of
verifying the suitability and applicability as to the intended purpose.
T: +49 89 74422 237
F: +49 89 74422 6237
cs-initiators.eu@united-in.com
T: +1 800 231 2702
F. +1 440 323 0898
cs-initiators.nafta@united-in.com
T: +86 20 6131 1370
F: +86 139 2503 8952
cs-initiators.cn@united-in.com
T: +61 2 9316 0046
F: +61 2 9316 0034
cs-initiators.au@united-in.com
www.united-initiators.com
Revision number: 1.0. Date: 12.09.14. Device M: TDS.
by | Sep 27, 2025
by | Sep 27, 2025
Technical Data Sheet
Description
Technical Data
! hi i ?’iF”f’* R 5
United lnitiators Ketone Dye Goncentrates
Methyl ethyl ketone peroxide
CAS# N/A
Liquid mixture
United SPI Dye Concentrates are available for selected Norox@ ketone
peroxide products to enable the user to ensure that the peroxide cure initiator
(“catalyst”) is being uniformly mixed and applied in unsaturated polyester and
vinyl ester resins. These dye concentrates are available in permanent or
fading formulations as described below.
Active oxygen
Form:
Specific Gravity @
25″ C:
Flash point (C.O.C.):
Flash point (SETA C.C.)
SADT:
Soluble in:
Slightly soluble in:
5.6 max
Liquid
1.15
200″F/93″C, min
150″F/66’C, min.
149’F (60″C)
Oxygenated organic solvents
Water
Application
BW-4 –
Blue dye concentrate for point of use addition, only. Available only in
one-gallon package size. Non-fading in the curing system. Fairly permanent in
cured resin, but with prolonged exposure to the sun, BW-4 will fade.
B-1 –
Fading blue dye concentrate for ketone peroxide formulations. This blue
dye concentrate will begin to fade as the resin is completing gelation, to an
almost colorless state when the resin has cured. For point of use addition, only
Available only in one-gallon package size.
Y-5 –
Non-fading yellow dye for most standard, low water content ketone
peroxides. Not recommended for high water content peroxides. For point of use
addition. Available only in one-gallon package size.
R-4 –
Non-fading red dye concentrate especially suitable for high water content
ketone peroxide formulations. lt can also be used in low water content
peroxides. Available for point of use addition, or pre-added to the appropriate
peroxides at the time of manufacture.
Technical Data Sheet
i lri i’1″ 3 A’l”i-; i:; i:’
R-5 –
Non-fading red dye for most standard, low water content ketone
peroxides. Not recommended for high water content peroxides. Peroxide
products for which this is a suitable dye can be pre-dyed at the time of
manufacture or added at point of use. Available in 18 cc bottles and one-gallon
packages for point of use addition.
FR-1 –
Fading red dye concentrate for ketone peroxide product formulations.
This dye concentrate will begin to fade as the resin is completing gelation to an
almost colorless state when the resin has cured. Available for suitable pre-dyed
peroxide products and in one fluid ounce bottles and one-gallon package sizes
for point of use addition.
Warning –
These dye concentrates have been tested for performance and
stability only in United SPI peroxides. Use in other manufacturers’ products is
not recommended, and United SPI will not accept any liability for safety and/or
performance shortcomings of any concentrate used in any product not
manufactured by us. We do not recommend the use of fading dyes in gel coats
or color critical applications.
PACKAGING, SHIPPING & AVAILABILITY
The standard package sizes of NOROX@ UNITED KETONE DYE
CONCENTRATES are 4xB lb and 44lb (20 kg) polyethylene bottles.
NOROX@ UNITED KETONE DYE CONCENTRATES is available pre-
dyed in a4 lb (20k9) bottles. Please see United lnitiators, lnc. TDS for
Peroxide Dye Concentrates.
Classification –
Please refer to the specific NOROX@ UNITED
KETONE DYE CONCENTRATES Safety Data Sheet (SDS) under
section 14 &15, shipping & regulatory information. NOTE: SDS’s for
all United lnitiators, lnc. products may be requested by contacting the
company.
NOROX@ UNITED KETONE DYE CONCENTRATES is available
through a global network. Call United lnitiators, lnc. for the name of
the distributor in your area
Changes due lo technical progress and corporate advancement reserued. Any existing third-party @pyrights are to be taken inlo accounl.
verifying the suitability and applicabilily as to the intended purpose.
a
f: +49 89 74422 237
F: +49 89 74422 6237
cs-i nitiators.eu@united-in.com
T: +1 800 231 2702
F. +1 440 323 0898
cs-initiators.naft a@united-in,com
T: +86 20 613’1 1370
F: +86 1 39 2503 8952
cs-initiators.cn@united-in.com
T: +61 2 9316 0046
F: +61 2 9316 0034
cs-initiators.au@united-in.com
Revision number: 1.0. Date: 03.03.14. Device M: TDS.
www,united-initiators.com
by | Sep 27, 2025
Technical Data Sheet
Description
Technical Data
! hi i ?’iF”f’* R 5
United lnitiators Ketone Dye Goncentrates
Methyl ethyl ketone peroxide
CAS# N/A
Liquid mixture
United SPI Dye Concentrates are available for selected Norox@ ketone
peroxide products to enable the user to ensure that the peroxide cure initiator
(“catalyst”) is being uniformly mixed and applied in unsaturated polyester and
vinyl ester resins. These dye concentrates are available in permanent or
fading formulations as described below.
Active oxygen
Form:
Specific Gravity @
25″ C:
Flash point (C.O.C.):
Flash point (SETA C.C.)
SADT:
Soluble in:
Slightly soluble in:
5.6 max
Liquid
1.15
200″F/93″C, min
150″F/66’C, min.
149’F (60″C)
Oxygenated organic solvents
Water
Application
BW-4 –
Blue dye concentrate for point of use addition, only. Available only in
one-gallon package size. Non-fading in the curing system. Fairly permanent in
cured resin, but with prolonged exposure to the sun, BW-4 will fade.
B-1 –
Fading blue dye concentrate for ketone peroxide formulations. This blue
dye concentrate will begin to fade as the resin is completing gelation, to an
almost colorless state when the resin has cured. For point of use addition, only
Available only in one-gallon package size.
Y-5 –
Non-fading yellow dye for most standard, low water content ketone
peroxides. Not recommended for high water content peroxides. For point of use
addition. Available only in one-gallon package size.
R-4 –
Non-fading red dye concentrate especially suitable for high water content
ketone peroxide formulations. lt can also be used in low water content
peroxides. Available for point of use addition, or pre-added to the appropriate
peroxides at the time of manufacture.
Technical Data Sheet
i lri i’1″ 3 A’l”i-; i:; i:’
R-5 –
Non-fading red dye for most standard, low water content ketone
peroxides. Not recommended for high water content peroxides. Peroxide
products for which this is a suitable dye can be pre-dyed at the time of
manufacture or added at point of use. Available in 18 cc bottles and one-gallon
packages for point of use addition.
FR-1 –
Fading red dye concentrate for ketone peroxide product formulations.
This dye concentrate will begin to fade as the resin is completing gelation to an
almost colorless state when the resin has cured. Available for suitable pre-dyed
peroxide products and in one fluid ounce bottles and one-gallon package sizes
for point of use addition.
Warning –
These dye concentrates have been tested for performance and
stability only in United SPI peroxides. Use in other manufacturers’ products is
not recommended, and United SPI will not accept any liability for safety and/or
performance shortcomings of any concentrate used in any product not
manufactured by us. We do not recommend the use of fading dyes in gel coats
or color critical applications.
PACKAGING, SHIPPING & AVAILABILITY
The standard package sizes of NOROX@ UNITED KETONE DYE
CONCENTRATES are 4xB lb and 44lb (20 kg) polyethylene bottles.
NOROX@ UNITED KETONE DYE CONCENTRATES is available pre-
dyed in a4 lb (20k9) bottles. Please see United lnitiators, lnc. TDS for
Peroxide Dye Concentrates.
Classification –
Please refer to the specific NOROX@ UNITED
KETONE DYE CONCENTRATES Safety Data Sheet (SDS) under
section 14 &15, shipping & regulatory information. NOTE: SDS’s for
all United lnitiators, lnc. products may be requested by contacting the
company.
NOROX@ UNITED KETONE DYE CONCENTRATES is available
through a global network. Call United lnitiators, lnc. for the name of
the distributor in your area
Changes due lo technical progress and corporate advancement reserued. Any existing third-party @pyrights are to be taken inlo accounl.
verifying the suitability and applicabilily as to the intended purpose.
a
f: +49 89 74422 237
F: +49 89 74422 6237
cs-i nitiators.eu@united-in.com
T: +1 800 231 2702
F. +1 440 323 0898
cs-initiators.naft a@united-in,com
T: +86 20 613’1 1370
F: +86 1 39 2503 8952
cs-initiators.cn@united-in.com
T: +61 2 9316 0046
F: +61 2 9316 0034
cs-initiators.au@united-in.com
Revision number: 1.0. Date: 03.03.14. Device M: TDS.
www,united-initiators.com
by | Sep 27, 2025
Technical Data Sheet
Description
Technical Data
! hi i ?’iF”f’* R 5
United lnitiators Ketone Dye Goncentrates
Methyl ethyl ketone peroxide
CAS# N/A
Liquid mixture
United SPI Dye Concentrates are available for selected Norox@ ketone
peroxide products to enable the user to ensure that the peroxide cure initiator
(“catalyst”) is being uniformly mixed and applied in unsaturated polyester and
vinyl ester resins. These dye concentrates are available in permanent or
fading formulations as described below.
Active oxygen
Form:
Specific Gravity @
25″ C:
Flash point (C.O.C.):
Flash point (SETA C.C.)
SADT:
Soluble in:
Slightly soluble in:
5.6 max
Liquid
1.15
200″F/93″C, min
150″F/66’C, min.
149’F (60″C)
Oxygenated organic solvents
Water
Application
BW-4 –
Blue dye concentrate for point of use addition, only. Available only in
one-gallon package size. Non-fading in the curing system. Fairly permanent in
cured resin, but with prolonged exposure to the sun, BW-4 will fade.
B-1 –
Fading blue dye concentrate for ketone peroxide formulations. This blue
dye concentrate will begin to fade as the resin is completing gelation, to an
almost colorless state when the resin has cured. For point of use addition, only
Available only in one-gallon package size.
Y-5 –
Non-fading yellow dye for most standard, low water content ketone
peroxides. Not recommended for high water content peroxides. For point of use
addition. Available only in one-gallon package size.
R-4 –
Non-fading red dye concentrate especially suitable for high water content
ketone peroxide formulations. lt can also be used in low water content
peroxides. Available for point of use addition, or pre-added to the appropriate
peroxides at the time of manufacture.
Technical Data Sheet
i lri i’1″ 3 A’l”i-; i:; i:’
R-5 –
Non-fading red dye for most standard, low water content ketone
peroxides. Not recommended for high water content peroxides. Peroxide
products for which this is a suitable dye can be pre-dyed at the time of
manufacture or added at point of use. Available in 18 cc bottles and one-gallon
packages for point of use addition.
FR-1 –
Fading red dye concentrate for ketone peroxide product formulations.
This dye concentrate will begin to fade as the resin is completing gelation to an
almost colorless state when the resin has cured. Available for suitable pre-dyed
peroxide products and in one fluid ounce bottles and one-gallon package sizes
for point of use addition.
Warning –
These dye concentrates have been tested for performance and
stability only in United SPI peroxides. Use in other manufacturers’ products is
not recommended, and United SPI will not accept any liability for safety and/or
performance shortcomings of any concentrate used in any product not
manufactured by us. We do not recommend the use of fading dyes in gel coats
or color critical applications.
PACKAGING, SHIPPING & AVAILABILITY
The standard package sizes of NOROX@ UNITED KETONE DYE
CONCENTRATES are 4xB lb and 44lb (20 kg) polyethylene bottles.
NOROX@ UNITED KETONE DYE CONCENTRATES is available pre-
dyed in a4 lb (20k9) bottles. Please see United lnitiators, lnc. TDS for
Peroxide Dye Concentrates.
Classification –
Please refer to the specific NOROX@ UNITED
KETONE DYE CONCENTRATES Safety Data Sheet (SDS) under
section 14 &15, shipping & regulatory information. NOTE: SDS’s for
all United lnitiators, lnc. products may be requested by contacting the
company.
NOROX@ UNITED KETONE DYE CONCENTRATES is available
through a global network. Call United lnitiators, lnc. for the name of
the distributor in your area
Changes due lo technical progress and corporate advancement reserued. Any existing third-party @pyrights are to be taken inlo accounl.
verifying the suitability and applicabilily as to the intended purpose.
a
f: +49 89 74422 237
F: +49 89 74422 6237
cs-i nitiators.eu@united-in.com
T: +1 800 231 2702
F. +1 440 323 0898
cs-initiators.naft a@united-in,com
T: +86 20 613’1 1370
F: +86 1 39 2503 8952
cs-initiators.cn@united-in.com
T: +61 2 9316 0046
F: +61 2 9316 0034
cs-initiators.au@united-in.com
Revision number: 1.0. Date: 03.03.14. Device M: TDS.
www,united-initiators.com
by | Sep 27, 2025
Technical Data Sheet
Description
Technical Data
! hi i ?’iF”f’* R 5
United lnitiators Ketone Dye Goncentrates
Methyl ethyl ketone peroxide
CAS# N/A
Liquid mixture
United SPI Dye Concentrates are available for selected Norox@ ketone
peroxide products to enable the user to ensure that the peroxide cure initiator
(“catalyst”) is being uniformly mixed and applied in unsaturated polyester and
vinyl ester resins. These dye concentrates are available in permanent or
fading formulations as described below.
Active oxygen
Form:
Specific Gravity @
25″ C:
Flash point (C.O.C.):
Flash point (SETA C.C.)
SADT:
Soluble in:
Slightly soluble in:
5.6 max
Liquid
1.15
200″F/93″C, min
150″F/66’C, min.
149’F (60″C)
Oxygenated organic solvents
Water
Application
BW-4 –
Blue dye concentrate for point of use addition, only. Available only in
one-gallon package size. Non-fading in the curing system. Fairly permanent in
cured resin, but with prolonged exposure to the sun, BW-4 will fade.
B-1 –
Fading blue dye concentrate for ketone peroxide formulations. This blue
dye concentrate will begin to fade as the resin is completing gelation, to an
almost colorless state when the resin has cured. For point of use addition, only
Available only in one-gallon package size.
Y-5 –
Non-fading yellow dye for most standard, low water content ketone
peroxides. Not recommended for high water content peroxides. For point of use
addition. Available only in one-gallon package size.
R-4 –
Non-fading red dye concentrate especially suitable for high water content
ketone peroxide formulations. lt can also be used in low water content
peroxides. Available for point of use addition, or pre-added to the appropriate
peroxides at the time of manufacture.
Technical Data Sheet
i lri i’1″ 3 A’l”i-; i:; i:’
R-5 –
Non-fading red dye for most standard, low water content ketone
peroxides. Not recommended for high water content peroxides. Peroxide
products for which this is a suitable dye can be pre-dyed at the time of
manufacture or added at point of use. Available in 18 cc bottles and one-gallon
packages for point of use addition.
FR-1 –
Fading red dye concentrate for ketone peroxide product formulations.
This dye concentrate will begin to fade as the resin is completing gelation to an
almost colorless state when the resin has cured. Available for suitable pre-dyed
peroxide products and in one fluid ounce bottles and one-gallon package sizes
for point of use addition.
Warning –
These dye concentrates have been tested for performance and
stability only in United SPI peroxides. Use in other manufacturers’ products is
not recommended, and United SPI will not accept any liability for safety and/or
performance shortcomings of any concentrate used in any product not
manufactured by us. We do not recommend the use of fading dyes in gel coats
or color critical applications.
PACKAGING, SHIPPING & AVAILABILITY
The standard package sizes of NOROX@ UNITED KETONE DYE
CONCENTRATES are 4xB lb and 44lb (20 kg) polyethylene bottles.
NOROX@ UNITED KETONE DYE CONCENTRATES is available pre-
dyed in a4 lb (20k9) bottles. Please see United lnitiators, lnc. TDS for
Peroxide Dye Concentrates.
Classification –
Please refer to the specific NOROX@ UNITED
KETONE DYE CONCENTRATES Safety Data Sheet (SDS) under
section 14 &15, shipping & regulatory information. NOTE: SDS’s for
all United lnitiators, lnc. products may be requested by contacting the
company.
NOROX@ UNITED KETONE DYE CONCENTRATES is available
through a global network. Call United lnitiators, lnc. for the name of
the distributor in your area
Changes due lo technical progress and corporate advancement reserued. Any existing third-party @pyrights are to be taken inlo accounl.
verifying the suitability and applicabilily as to the intended purpose.
a
f: +49 89 74422 237
F: +49 89 74422 6237
cs-i nitiators.eu@united-in.com
T: +1 800 231 2702
F. +1 440 323 0898
cs-initiators.naft a@united-in,com
T: +86 20 613’1 1370
F: +86 1 39 2503 8952
cs-initiators.cn@united-in.com
T: +61 2 9316 0046
F: +61 2 9316 0034
cs-initiators.au@united-in.com
Revision number: 1.0. Date: 03.03.14. Device M: TDS.
www,united-initiators.com
by | Sep 27, 2025
Technical Data Sheet
BENOX
C-50
Dibenzoylperoxide
CAS#94-36-0
50 % powder with phthalate
Structural Formula
Description
Benox is a white, free-flowing, granular powder consisting of 50%
dibenzoyl peroxide, phthalate ester plasticizer.This peroxide can be
used as a cure initiator for unsaturated polyester resins and acrylic
resins in both elevated temperature cure and ambient temperature
cure (in combination with amine accelerators) processes. Benox is
easy to disperse and dissolves fast in unsaturated polyester and
acrylic resins.
The system Benox C-50/Amine gives you a very fast cure that is hardly
influenced by the humidity and fillers. Even at low temperature a relatively
good cure will be obtained.
Technical Data
Peroxide Content 50 %
Active oxygen 3.30 %
Appearance White, free-flowing powder
”Kick-off” Temperature 70 C
10-hr Half-life temperature (0.1 mole in
benzene)
72 C
Critical temperature (SADT) 60 C
Recommended storage temperature Max 30 C
Soluble in Phthalates
Insoluble in Water
Maintenance of activity as from date of
delivery
6 months
Application
AMBIENT TEMPERATURE CURING
Benox is typically used in ambient temperature processes at
levels of 2% – 5%, as supplied, on weight of resin, in combination
with 1% – 3% amine accelerator (typically 10% dimethylaniline
solution in phthalate).
Caution: Do not mix Benox directly with amine accelerators
violent decomposition will occur! Thoroughly mix one with the
resin prior to adding the other.
Technical Data Sheet
Benox is characterized by relatively fast cure with moderate to high exotherms
in most resin systems, resulting in relatively short demoulding times. Possible
application: Roof covering, floorings, chemical anchors, road marking paints.
ELEVATED TEMPERATURE CURING
Benox can be used singly, or in combination with other elevated
temperature cure peroxides, in processes with operating
temperatures above 70 C (176 F). When used singly,
approximately 0.5% of amine accelerator (as described above) is
recommended for thorough cure. Omission of the accelerator
often results in only a moderate degree of cure, even after post
curing.
Benox can also be used in combination with one or more elevated
temperature cure peroxides such as peroxyesters, peroxyketals and/or
peroxydicarbonates in processes such as Pultrusion, cured-in-place-pipe, and
wet press moulding. Amine accelerators are not typically used in these
applications.
Measurements
AMBIENT TEMPERATURE CURING
(2mm laminate @23 C / 73 F)
Formulation (parts by
wt)
High Reactive Ortho
Resin
100 100 100 100 100 100
Benox 4 4 4 2 2 2
10% DMA Solution 2 1 0.5 2 1 0.5
Cure Data (minutes)
Gel Time 6 10 30 10 19 44
Mould Release Time 10 15 50 20 35 90
Cure Temperature 50 C 60 C 80 C 95 C
Formulation (parts
by wt)
High Reactive Ortho
Resin
100 100 100 100 100 100 100 100
Benox 2 2 2 2 2 2 2 2
10% DMA Solution — 0.5 — 0.5 — 0.5 — 0.5
Cure data
(minutes)
Gel Time >60 8 30 5 8 4 3 3
Mould Release Time — 10 35 7 10 5 5 4
It must be emphasized that the data above applies to only one resin. Potential
users of similar systems must evaluate their specific resin(s) prior to
production use of Benox
.
Technical Data Sheet
Storage
Store in original containers away from flammables and all sources of heat,
sparks, or flames; out of direct sunlight; and away from cobalt naphthenate,
anilines, other promoters, accelerators, oxidizing or reducing agents and
strong acids or bases.
Packaging
The standard package sizes of BENOX C-50 is 25 kg in a PE bag placed in
cardboard box. Weights are on a net weight basis.
Disclaimer
This information and all further technical advice are reflecting our present knowledge and experience based on internal tests with local raw materials with the purpose to inform about
our products and applications. The information should not be construed as guaranteeing specific properties of products described or their suitability for a particular application, nor as
providing complete instructions for use. The information implies no guarantee for product and shelf life properties, nor any liability or other legal responsibility on our part, including
with regard to existing third party intellectual property rights, especially patent rights. We reserve the right to make any changes according to technological progress or further
developments.
Application and usage of our products based on our technical advice is out of our control and sole responsibility of the user. The user is not released from the obligation to conduct
careful inspection and testing of incoming goods in order to verify the suitability for the intended application.
United Initiators
EU
United Initiators
Nafta
United Initiators
China
United Initiators
Australia
T: +49 89 74422 237
F: +49 89 74422 6237
cs-initiators.eu@united-in.com
T: +1 800 231 2702
F. +1 440 323 0898
cs-initiators.nafta@united-in.com
T: +86 20 6131 1370
F: +86 139 2503 8952
cs-initiators.cn@united-in.com
T: +61 2 9316 0046
F: +61 2 9316 0034
cs-initiators.au@united-in.com
www.united-initiators.com
Revision number: 1.0. Date: 03.03.14. Device M: TDS.
by | Sep 27, 2025
Technical Data Sheet
BENOX
B-50 & B-55
Dibenzoyl Peroxide Paste
CAS# 94-36-0
Description
BENOX B-50 & B-55 are fine dispersions of dibenzoyl peroxide in a smooth,
non-separating fire resistant creamy paste form. The patented (U.S. Patent
No. 5,334,326) benzoate plasticizer diluent system provides product
formulations that can be readily dissolved in resins and monomers. These
products are less hazardous and easier to use than technical or dry forms of
dibenzoyl peroxide provided the plasticizer and water content are not
objectionable. Additional benefits of the benzoate plasticizer system include
better resistance to the dispersion of heat degradation and the elimination of
phthalate ester plasticizers.
BENOX B-50-106 Creamy, white, non-separating paste containing 50%
dibenzoyl peroxide. Primarily formulated for use with auto body filler.
BENOX B-50-210 Blue pigmented version of 50% dibenzoyl peroxide in
paste form. B50-210 is a creamy, non-separating product formulated for use
with auto body filler.
BENOX B-50-230 Lighter Blue pigmented version of 50% dibenzoyl
peroxide in paste form. B50-230 is a creamy, non-separating product
formulated for use with auto body filler. For customers that prefer a lighter blue
paste hardener.
BENOX B-50-513 Red pigmented 50% dibenzoyl peroxide paste. This
product is the most popular in the B-50 line of creamy non-separating paste
formulations.
BENOX B-50-713 Onyx pigmented 50% dibenzoyl peroxide paste. B50-713
is a creamy, non-separating product formulated for use with auto body filler.
BENOX B-55-107 A basic white, paste form of 55% dibenzoyl peroxide
formulated primarily for use in the mine bolt industry and other industries
which require a product that can be further diluted prior to use.
BENOX B-55-108 This white, paste form of 55% dibenzoyl peroxide is
formulated for use in ambient and elevated temperature curing of unsaturated
polyester resins. B-55-108 is characterized by its lower water content and
creamy non-separating form, compared to the 107 formulation.
Technical Data Benox B- 50 Benox B-55
Dibenzoyl Peroxide Content: 50 55
Active oxygen 3.3 3.6
Form: Thixotropic Cream
Color: White
Soluble in: Oxygenated & aromatic solvents
Slightly soluble in: Alcohols & petroleum solvents
Insoluble in: Chlorinated solvents
Technical Data Sheet
Application
BENOX B-50 & B-55 is principally used as polymerization initiators and curing
agents for monomeric vinyl, acrylic, styrene and unsaturated polyester/vinyl
ester resins, and copolymers of these resins, provided the plasticizer and water
content can be tolerated. This product has advantages over dry, granular
products, and include:
1. Marked reduction of hazards involved in handling and storage.
2. The homogeneous dispersion of extremely fine particles of dibenzoyl
peroxide in plasticizer dissolves more readily in resins and eliminates the
hazardous practice of dissolving dry dibenzoyl peroxide in styrene, acetone, or
other volatile solvents.
ROOM TEMPERATURE MOLDING
BENOX B-50 & B-55 can be used for room temperature curing of pre-promoted
polyester and vinyl ester resins. Dimethyl or diethyl aniline are the most
generally used, but another that can be used is N, N-dimethyl-p-toluidine. These
promoters, or accelerators, are generally used in concentrations between 0.01%
and 0.6%, on weight of resin. The B-50 & B-55 use levels can be between 0.5%
and 5.0%, depending on the desired gel and cure properties.
CAUTION: ABSOLUTE CARE MUST BE TAKEN TO PREVENT DI RECT
MIXING OF B-50 & B-55 WITH ANY OTHER PROMOTER. DOIN G SO COULD
CAUSE A VIOLENT DECOMPOSITION RESULTING IN A FIRE O R
EXPLOSION.
AUTO BODY FILLER
BENOX B-50 is used to cure auto body patching compound formulated with
unsaturated polyester resin. The creamy paste form of BENOX B-50 allows the
user to easily and uniformly mix the peroxide with the patching compound for a
rapid, uniform cure. BENOX B-50 is available in several colors which serve as
a visual guide to ensure uniform dispersion in the patching compound.
Repackaging of the peroxide in peroxide in polyethylene tubes or jars is easily
accomplished, but extreme care should be taken to avoid contamination. Use
only clean and dust-free containers for repackaging.
ELEVATED-TEMPERATURE MOLDING
BENOX B-55 is widely used in elevated in the elevated-temperature curing of
polyester compounds in heated molds. The practical operating temperatures of
BENOX B-55 initiated resin curing are between 180 F and 300 F. Processes
which can use BENOX B-55 include matched-metal molding, hot press
molding, bag molding, compression and transfer molding.
ADHESIVES
B-50 & B-55 may be used in two-part adhesive systems based on polyester or
methacrylate resins. The creamy consistency allows uniform mixing of the
components. The non-separating aspect of B-50 & B-55 allows repackaging into
smaller, more useable quantities.
Technical Data Sheet
CHEMICAL STRUCTURE
PACKAGING, SHIPPING & AVAILABILITY
The standard package sizes of BENOX B-50 & B-55 are 50 lb. and
22 kg plastic pails and 175 kg polyethylene lined, fiberboard drum,
and 55 gallon poly drum. For custom package sizes, please contact
your local distributor or United Initiators, Inc.
Classification Please refer to the specific BENOX
B-50 & B-55
Safety Data Sheet (SDS) under section 14 & 15, shipping & regulatory
information. NOTE: SDS s for all United Initiators, Inc. products may
be requested by contacting the company.
BENOX B-50 & B-55 is available through a global network. Call
United Initiators, Inc. for the name of the distributor in your area
This information and our application-technical advice whether verbal, in writing or by way of trials reflect our present state of knowledge based on internal tests with local raw
materials. Their purpose is to inform interested parties about our products and their possible application. They should not be construed as guaranteeing specific product properties or
their suitability for a particular application. Furthermore, the information does not contain complete instructions for use. Nor does it constitute a guarantee as to quality and durability.
Changes due to technical progress and corporate advancement reserved. Any existing third-party copyrights are to be taken into account.
Application and use of our products based on our application-specific advice is beyond our control and sole responsibility of the user. The user is not released from the obligation of
verifying the suitability and applicability as to the intended purpose.
T: +49 89 74422 237
F: +49 89 74422 6237
cs-initiators.eu@united-in.com
T: +1 800 231 2702
F. +1 440 323 0898
cs-initiators.nafta@united-in.com
T: +86 20 6131 1370
F: +86 139 2503 8952
cs-initiators.cn@united-in.com
T: +61 2 9316 0046
F: +61 2 9316 0034
cs-initiators.au@united-in.com
www.united-initiators.com
Revision number: 1.0. Date: 24.07.14. Device M: TDS.
by | Sep 27, 2025
TS.SP.02.15US/04.03.2019/02
Yenibosna Merkez Mah. Ladin Sok. No:36/70 Townofis
34197 Bah elievler / STANBUL / TURKEY
t. +90 212 580 5559 f. +90 212 580 5521
www.akpakimya.com e. info@akpakimya.com
AKPEROX A9H
Description : Methyl Ethyl Ketone Peroxide in 2,4,4-trimethyl-1,3-pentanediol Diisobutyrate
Specifications;
Density (@20 C) : 1,1 0,005 gr/cm
3
Appearance : Colorless, Liquid
Diluent : Mix solvents
Active Oxygen Content : 8,75 – 8,95 %
Peroxide Content : 34 – 36 %
SADT : 60 C
CAS Nr. : 1338-23-4
EINECS/ELINCS Nr : 700-954-4
REACH Reg. No : 01-2119514691-43-0007
UN No. : 3105
Application : AKPEROX A9H is a general purpose MEKP for curing unsaturated polyester (UP)
resins at room temperature.
Usage & Amount : It is recommended to use 1% – 2% in general, depending on application. Needs to
be used with Cobalt accelerators at room temperature. (E.g. AKCOBALT 1%)
Packaging : 30 Kgs Jerry Can, 5 Kgs Jerry Can, 4×5 Kg in a Carton Box.
Handling & Storage : Must be kept between +5 C and +30 C. Keep pails tightly closed. Store and
handle in a dry, well- ventilated place, away from sources of heat, ignition and
direct sunlight in original packaging. Provide grounding and venting in order to
prevent static electricity build-up. Avoid any contact with Amine and Cobalt
Accelerators, acids, alkalis and heavy metal compounds such as driers and metal
soaps. Storage Class; IIA
Shelf Life : 8 Months
For unopened packages at recommended storage conditions.
by | Sep 27, 2025
TS.SP.02.14R1US/27.09.2022/03
Yenibosna Merkez Mah. Ladin Sok. No:36/70 Townofis
34197 Bah elievler / STANBUL / TURKEY
t. +90 212 580 5559 f. +90 212 580 5521
www.akpakimya.com e. info@akpakimya.com
AKPEROX A9CL FD
Description : Methyl Ethyl Ketone Peroxide in 2,4,4-trimethyl-1,3-pentanediol Diisobutyrate
Specifications;
Density (@20 C) : 1,14 0,005 gr/cm
3
Viscosity (@20 C) : 22-25 mPa.s
Appearance : Red, Liquid
Diluent : 2,2,4-trimethyl-1,3-pentanediol diisobutyrate
Active Oxygen Content : 8,75 – 8,95 %
Peroxide Content : 34 – 36 %
SADT : 65 C
CAS Nr. : 1338-23-4
EINECS/ELINCS Nr : 700-954-4
REACH Reg. No : 01-2119514691-43-0007
UN No. : 3105
Application : AKPEROX A9CL FD is a multipurpose catalyst for the room temperature cure of
promoted unsaturared polyester resins. The resin ca be heat-cured with AKPEROX
A9CL in a temperature range of 100-127 C.
Usage & Amount : It is recommended to use 1% – 2% in general, depending on application. Needs to be
used with Cobalt accelerators at room temperature. (E.g. AKCOBALT 1%)
Packaging : 30 Kgs Jerry Can, 5 Kgs Jerry Can, 4×5 Kg in a Carton Box.
Handling & Storage : Must be kept max at +30 C. Keep pails tightly closed. Store and handle in a dry, well-
ventilated place, away from sources of heat, ignition and direct sunlight in original
packaging. Provide grounding and venting in order to prevent static electricity build-
up. Avoid any contact with Amine and Cobalt Accelerators, acids, alkalis and heavy
metal compounds such as driers and metal soaps. Storage Class; IIA
Shelf Life : At least 12 Months
For unopened packages at recommended storage conditions.
