Hydropel H125-A Series
Vinyl Ester Formulation
Premium High
Performance Vinyl
Ester Laminating
Formulation
AOC’s Hydropel H125-A Series is a
thixotropic, pre-promoted, 100% epoxy
based vinyl ester formulation.
Application
AOC s Hydropel H125-A Series is designed for use
in the manufacturing of boats, backing
thermoformed acrylic, and construction of other
various composite parts, using hand lay up and
spray up techniques.
Typical Cast Mechanical Properties*
1
See Back Page
Test Unit of Measure Nominal Test Method
Tensile Strength psi/MPa 13,600/94 ASTM D638
Tensile Modulus psi/GPa 530,000/3.7 ASTM D638
Tensile Elongation % 6.0 ASTM D638
Flexural Strength psi/MPa 22,300/154 ASTM D790
Flexural Modulus psi/GPa 560,000/3.9 ASTM D790
Heat Distortion
Temp.
F/ C @ 264 psi 239/115 ASTM D648
*Typical properties are not to be construed as specifications.
Typical Liquid Properties*
2
See Back Page
Test Unit of Measure Nominal
Viscosity @ 25 C/77 F LV
Spindle #3 @ 60 rpm
cps 625
Thix Index 6/60
– 2.9
Styrene Content
% 35
25 C Gel Time, 100g
1.5% MEKP-925H
minutes 42
Total Cure Time
minutes 9
Peak Exotherm
F/ C 347/175
Benefits
Provides maximum resistance to osmotic
blistering even when used for only the skin
coat
Outstanding strength and toughness of the
composite
Provides excellent resistance to cracking
caused by flexural failure of the laminate
Meets MACT requirements for low HAP
resins in the marine industry
2
Americas
+1 866 319 8827
americas@aocformulations.com
AOC is a registered trademark of the AOC group of companies.
The user is held responsible for checking the quality, safety and all
other properties of our products prior to use. The information and recommendations contained herein
are to the best of our knowledge accurate and reliable, but no rights whatsoever may be derived by any
party other than those expressly agreed to with a selling entity of the AOC group of companies in a
legally binding agreement. AOC hereby makes no warranty of any kind, express or implied, including
those of merchantability and fitness for purpose. Unless explicitly agreed to in writing by AOC other-
wise, all offers, quotations, sales and deliveries of AOC products are subject to the general conditions of
sale of AOC. Altek
, Atlac
, Atryl
, Beyone
, Chroma-Tek
,, Daron
, Firepel
, Hydropel
, MoldTru
,
NeoMould
, Neoxil
, Palatal
, Palapreg
, Pultru
, SynoliteVibrin
, Vicast
, Vipel
, the AOC
name, the
AOC logo and the Trusted Solutions
logo are the registered trademarks of the AOC group of companies.
For more information: aocformulations.com
Performance Guidelines
A. Keep full strength catalyst levels
between 1.25% – 2.0% of the total for-
mulation weight.
B. Maintain shop temperatures be-
tween 65 F/18 C and 90 F/32 C and
humidity between 40% and 90%. Con-
sistent shop conditions contribute to
consistent gel times and will help the
fabricator make a high quality part.
Storage Guidelines
Resins are stable for three months
from date of production when stored
in the original containers away from
sunlight at no more than 70 F/21 C.
During the hot summer months, no
more than two months stability at
86 F/30 C should be anticipated. After
extended storage, some drift may occur
in gel time and viscosity.
Storage in plastic totes made out of
materials such as polyethylene (PE) or
polypropylene (PP), in particular translu-
cent PE/PP, will accelerate gel formation
and result in a significantly reduced stor-
age stability.
Storage of this formulation outdoors
in translucent plastic totes may reduce
the storage stability to only a few
weeks. AOC cannot assume responsi-
bility for gel formation under these
storage conditions.
Application Guidelines
Due to the curing characteristics of the
Hydropel H125-A Series formulation, it
is desirable to complete all secondary
bonding as soon as possible. Exposure
of the laminate to sunlight will result in
severe secondary bonding problems.
After 24 hours of cure, it may become
necessary to abrade the laminate to
insure good secondary bonding, espe-
cially if the surface of the laminate has
been allowed to become resin rich.
Low fiberglass content and resin pud-
dling should be avoided with this
product.
To assure adequate bonding to acryl-
ics, fabricators should pre-wet the
acrylic surface with a thin pass of cata-
lyzed resin prior to lamination.
The ability of an unsaturated polyester
resin to bond to acrylic is influenced
by many factors. Resin is only one of
the factors. The type and color of the
acrylic used and the conditions during
the thermoforming process are but a
few of the factors that affect the ability
of the resin to bond to the acrylic.
Therefore, it is vitally important that
the fabricator evaluates for themselves
the fitness of this product for their
processes.
To ensure a high quality fabricated
part, AOC recommends that fabrica-
tors utilize Best Practice Guidelines
for polyester resins, vinyl ester resins,
acrylic sheet.
ISO 9001:2015 Certified
The Quality Management Systems at
every AOC manufacturing facility have
been certified as meeting ISO
9001:2015 standards. This certification
recognizes that each AOC facility has an
internationally accepted model in place
for managing and assuring quality. We
follow the practices set forth in this
model to add value to the products we
make for our customers.
Material Safety
See the appropriate Safety Data Sheet
for guidelines.
Test Methods
(1.) Based on tests at 77 F/25 C and 50% relative
humidity. All tests performed on unreinforced
cured resin castings. Thixotropic components, if
applicable, are excluded from casting samples.
Castings were post cured.
(2.) The gel times shown are typical but may be
affected by catalyst, promoter, inhibitor concen-
tration, resin, mold, and shop temperature. Varia-
tions in gelling characteristics can be expected
between different lots of catalysts and at ex-
tremely high humidities. Pigment and/or filler can
retard or accelerate gelation. It is recommended
that the fabricator check the gelling characteris-
tics of a small quantity of resin under actual oper-
ating conditions prior to use.
Hydropel H125-A Series
Vinyl Ester Formulation
Pub. H125-A Series
Last update: August 8, 2024
2024 AOC