Title of Invention

HARDENER AND METHOD FOR CURING OF EPOXY RESINS.

Abstract Hardener for curing of epoxy resins which produces materials with high abrasion resistance, photostability and chemical resistance. The hardener comprises a sol prepared by controlled hydrolysis and condensation of compounds of the type: (X-B-)n Si(-Y)4-n where n = 1 or 2, X = SH, -N=C=O, or NR1R2, R1, R2 being chosen from hydrogen, saturated or unsaturated C1-C18-alkyl, substituted or non-substituted aryl, formyl, aliphatic or aromatic carbonyl, carbamoyl, sulphonyl, sulphoxyl, phosphonyl, sulphinyl, phosphinyl, while the carbon chains of said compounds may include one or more of the elements oxygen, nitrogen, sulphur, phosphorus, silicon and boron, and/or may include one or more hydrolysable silane units, or R 1, R2 are chosen from condensation products or addition products of one or more types or chemical compounds such as acids, alcohols, phenols, amines, aldehydes or epoxides. B is a spacing group chosen from saturated or unsaturated C1-C18-alkylene, substituted or nonsubstituted arylene, while the carbon chains of the stated compounds may optionally include one or more of the elements oxygen, nitrogen, sulphur, phosphorus, silicon and boron. Y is chosen from hydrolisable groups such as alkoxy, carboxyl, and halogen.
Full Text Epoxy resin curing agent for enhanced wear resistance and weatherability of cured materials
The invention concerns a hardener for epoxy resins which produce materials with very high colour
stability, abrasion, scratch and chemical resistance. The invention also pertains a method for
curing an epoxy resin utilizing such a hardener as well as a cured epoxy material manufactured in
this manner.
Background
Commercially available epoxy resins in combination with commercially available hardeners
produce materials with a broad application as coatings for corrosion protection, components of
composite materials and as moulding plastics. In addition to the basic components of epoxy resin
and hardener the starting materials may contain dyes, pigments, fillers, reactive and non-reactive
diluents, volatile solvents, stabilizing agents and additives.
Epoxy resins usually contain more than one 1,2-epoxy group per mole and may be based on
saturated, unsaturated, aromatic, aliphatic, cycloaliphatic or heterocyclic structures.
Hardeners are usually chosen from the following groups of chemical compounds: aromatic,
aliphatic, cycloaliphatic or heterocyclic amines, amine adducts, polyamides, polyamido amides,
Mannich bases, ketimines or carboxylic acid derivatives. Mercaptan compounds can also be used
as active compounds within the hardener.
Fillers include titanium dioxide, silica, diverse silicates, minerals or carbon black.
Stabilisers include antioxidants, radical scavengers or UV-absorbers.
Additives include plasticizers, catalysts for the curing reaction, rheology modifying additives or
surfactants.
Reactive diluents are often epoxy compounds of considerably lower viscosity than the epoxy
resins.
It is known that the colour stability of materials which are made from commercially available
epoxy resins and hardeners is often poor because the hardeners or combination of hardener, resin
and additives, have a strong tendency to yellowing, also after curing. A known method of
reducing yellowing is to use amine based hardeners with aliphatic or cycloaliphatic structures,
because in the presence of light the yellowing of cycloaliphatic amines is significantly less than
that of aromatic amines.
The disadvantage of using aliphatic or cycloaliphatic amines as hardeners or curing agents is that
the abrasion and scratch resistance of the resulting materials is often poorer than for aromatic
amines.
It is also known that the abrasion, scratch and chemical resistance of cured epoxies can be
significantly improved by the use of fillers such as silica (US 3794609). The disadvantage

however is that the transparency of the hardened epoxy is considerably reduced, which is
perceived as detrimental, particularly when the material is intended for use as coating.
A known method of producing cured epoxies with high colour stability, abrasion, scratch and
chemical resistance, and acceptable transparency can therefore be to use hardeners based on
aliphatic or cycloaliphatic amines with low yellowing tendency together with silica based
nanoparticles as an additive. One example of silica based nanoparticles is the Aerosil® products
of Degussa AG, Germany. From EP 0774443 A1 it is known that nanodisperse titanium dioxide is
suitable for improving the colour stability of, amongst others, polymer based formulations.
An alternative method for the preparation of coatings with good abrasion, scratch and chemical
resistance together with acceptable transparency is based on organic, polymer forming components
and inorganic, particle containing or particle forming components where the particle size is
between 1 and 150 nm. The coating is usually cured by applying the mixture of organic and
inorganic components to a surface and drying with the aid of heat and/or UV-VIS radiation. Such
coating forming mixtures may contain epoxy resins or compounds with epoxy groups. A large
number of patents and publications exist which describe the preparation of such organic-inorganic
hybrid materials and possible applications: JP 09132637, US 5618860, US 5804616, WO 9832792
EP 496552, KR 2000059589, JP 2001288401 and Milena Spirkova et. al. "Hybrid Organic-
Inorganic Epoxide-Based Coatings Prepared by Sol-Gel Process", Proceedings of 6th Nürnberg
Congress on Creative Advances in Coatings Technology ", paper 12 (2001).
Thermosetting plastics such as epoxy resins can also be modified with nanodisperse inorganic
particles for applications other than coatings. DE 198 60 691 A1 describes a magnetic paste which
contains nanocrystals. WO 9631572 Al describes polymerisable, nanoparticle containing
formulations which, amongst others, are based on acrylic or epoxy resins and which can be used
for building up or joining of optoelectronic elements. WO 0130304 A1 describes materials which
are based on organic thermosets and inorganic nanoparticle containing or nanoparticle forming
components. The materials are used as dental replacement materials. In addition a number of
scientific publications describe the modification of thermosetting plastics such as epoxy resins
with nanoparticle containing or nanoparticle forming mixtures (e.g. Soo-Jin Park et. al. "Surface
Modification of Montmorillonite on Surface Acid-Base Characteristics of Clay and Thermal
Stability of Epoxy/Clay Nanocomposites ", Journal of Colloid and Interface Science 251, 160-165
(2002)).
Also the preparation of nitrogen containing, basic hardeners or curing agents with hydrolisable
silane compounds for thermosets such as epoxy resins is known. US 4988778 describes hardeners
which are prepared by partial alcoholysis/ aminolysis of y-aminopropyltrimethoxy silane with
diisopropyl amine, but without the addition of water. JP 04366159 describes a product which is
made by the reaction of ?-glycidopropyltrimethoxy silane with water and small quantities of an

amidine compound l,8-diazabicyclo[5.4.0]undeken-7 and which is used as a subcomponent for
curing of an epoxy containing thermosetting mixture. The basic amidine compound constitutes
however less than 62 ppm by weight of the silane/water mixture thus the product itself must be
considered as unsuitable as a hardener for epoxy resins.
It is also shown in PCT/NO2001/00287 that an existing organic lacquer or gelcoat can be modified
with suitable nanoparticle mixtures to, amongst other things, give improved scratch resistance.
Here a stable nanoparticle containing sol is prepared which is added to the existing organic
lacquer or gelcoat as required.
However, we believe, that the use of sol-gel mixtures, which are prepared by controlled
hydrolysis/condensation of ?-aminopropyltrialkoxy silane or other nitrogen containing silanes
and/or mercaptosilanes as hardener for epoxy resins has not been documented.
The sol-gel process is a simple way of preparing nanoparticle based mixtures. The sol-gel process
is based on a controlled hydrolysis/condensation of e.g. silane alkoxides. The process is described
in PCT/NO2001/00287 and yields gels which relatively easily can be mixed into polymeric and/or
polymerisable organic formulations.
One example is sols which are prepared by controlled hydrolysis/condensation of ?-
aminopropyltrialkoxy silane. The sol-gel process is in this case particularly simple because an
external catalyst is not required and because the process can be performed at room temperature or
with gentle heating.
Known hardeners for epoxy resins are based on amines such as 4,4"-diaminodiphenylmethane (I)
or meta-xylylenediamine (II):

Amines react with epoxy resins by crosslinking with two or more polymer chains in the epoxy
resins. This leads to solidification (hardening) of the two component system which consists of
amine based hardener and epoxy resin and the formation of a relatively abrasion resistant material.
The disadvantage of amine based hardeners is that the hardened material yellows relatively quickly
due to, amongst other things, oxidative degradation of components in the amine based hardener.

In addition the abrasion/scratch resistance of the hardened material is often too poor for the
material to be used for demanding applications.
Objective
The object of the present invention is to provide a hardener for epoxy resins that provides cured
epoxy materials with high abrasion resistance and photostability.
It is a further object to provide a hardener as mentioned above that provides materials with high
transparency and clarity.
It is still further an object of the invention to provide such a hardener that is easy to manufacture in
industrial scale, have a long shelf life and that is readily able to cure epoxy resins under normal
conditions.
The invention
In a first aspect the invention relates to a hardener for epoxy resins defined by the features
disclosed in the characterising part of claim 1.
According to a second aspect the invention relates to a cured epoxy resin as defined by claim 15.
According to a third aspect the invention concerns a method for curing epoxy resins as defined by
claim 16.
Preferred embodiments of the invention are disclosed by the dependent claims.
The first aspect of the invention concerns sol-gel based hardeners which can be used for curing
epoxy resins. In a first step a sol is prepared by controlled hydrolysis/condensation of suitable
amine containing hydrolisable and condensable silane compounds. Suitable amine containing
hydrolisable and condensable silane compounds are those comprised by the formula:
(X-B-)n Si(-Y)4-n (III)
where n=l or 2, X=SH, -N=C=O or NR1R2. NR1R2 is chosen among hydrogen, saturated
or unsaturated C1-C18-alkyl, substituted or not substituted aryl, formyl, aliphatic or
aromatic carbonyl, carbamoyl, sulfphonyl, sulphoxyl, phosphonyl, sulphinyl, phosphinyl,
wherin the carbon chains in said compounds optionally may contain one or more the
elements oxygen, nitrogen, sulphur, phosphorous, silicon, and boron, and/ or optionally
containing one or more hydrolysable silane units, or R1, R2 are chosen among
condensation products or addition products of one or more types of chemical compounds
such as acids, alchohols, phenols, amines, aldehydes or epoxides.

A simple way to prepare nanoparticle based compositions is the sol-gel process. The sol-gel
process is based on controlled hydrolysis/ condensation of e.g silane oxides. The process is
described in PCT/NO2001/00287 and results in gels that are comparatively easily mixable with
polymer containing or polymerizable organic formulations. One example is the preparation of sols
by controlled hydrolysis/ condensation of y-aminopropyltrialkoxysilane. In this case the sol-gel
process is particularly simple as no catalyst is required and the process may be conducted at
ambient temperature or with only slight warming.
The main difference in this invention in relation to the inventions in the above mentioned patents
and the results of the above mentioned publications is as follows: In the first step a stable sol is
prepared by controlled hydrolysis/condensation of a suitable, possibly appropriately modified,
silane compound. When stored under favourable conditions the product may be stable for six
months or longer. In the second step the sol is mixed with suitable epoxy resins, to give cured
materials with improved colour stability, abrasion, scratch and chemical resistance. As far as the
inventors know, no prior art describes stable sols with long stability as hardeners for epoxy resins
with two or more components.
Controlled hydrolysis/condensation of compounds as described in the characterisation part of
patent claim 1 generally results in a sol where the particle forming or oligomeric condensate
products have several more or less free amino groups on the surface. Thus these particles or
oligomers can react with thermosets such as epoxy resins by crosslinking with two or more
polymer chains in the thermoset, in the same way as the known amine based hardeners (I) and (II).
A corresponding curing reaction is possible with sols prepared by controlled hydrolysis
/condensation of other nitrogen containing silane compounds or mercaptosilanes, provided that the
sol contains particles or oligomers with a sufficiently large number of more or less free amino
groups and/or mercaptan groups. Generally the reaction products of the sol-gel process such as
alcohol or excess water must be removed before the sol can be used as a hardener or as a
component of a hardener for epoxy resins.
The crosslinking reaction and therefore the curing reaction between particle forming condensate
products with more or less free amino groups on the surface and an epoxy can be described as in
(IV):


Sometimes the stability of the sol can be too short, especially after the reaction products from the
sol-gel process such as alcohols or excess water have been removed. Also the rate of the curing
reaction between the sol and epoxy resin may be far from optimal such that the curing reaction
may be too fast or too slow. Adjustment of the rate of the curing reaction is desirable in such cases.
It may also be cases where that the compatibility and therefore the miscibility of the sol and the
epoxy resin are not good enough, which may, e.g., result in inadequate material properties in the
cured material. Also in such cases adjustment of compatibility is required. Modification of the
prepared sol by an appropriate chemical conversion can therefore be advantageous.
Suitable chemical conversions to modify the prepared sol have the aim to modify more or less free
amino groups at the surface of the particle forming condensate product. Such conversions are
conducted between more or less free amino groups at the surface of a particle forming condensate
product and reactive compounds that preferably reacts quantitatively with the more or less free
amino groups at temperatures T compounds are epoxides, acid derivatives, blocked and unblocked isocyanates and compounds R-
X comprised of
a) A suitable atom or an atom group X and
b) a group R

wherein R-X is able to react with more or less free amino groups in a substitution reaction by
which an atom or atom group X is replaced by an amino group (Endre Berner, "Laerebok i
organisk kjemi", Aschehoug & Co., Oslo (1964), p. 144-147) and where the group R is chosen
from non-substituted saturated or unsaturated C1-C24 alkyl, substituted saturated or unsaturated C1,
C24-alkyi, substituted or non-substituted aryl, aliphatic or aromatic carbonyl, wherein the carbon
chains of said compounds may optionally include one or more of the elements oxygen, nitrogen,
sulphur, silicon and boron, or groups chosen among condensation products or addition products o1
one or more types of chemical compounds such as acids, alcohols, phenols, amines, aldehydes or
epoxides, and
the atom or an atom group X preferably chosen among halogen, substituted or non-substituted
alkoxyl, phenoxyl, amine, carboxylate, sulphonate, sulphinate, phosphonate or phosphinate.
Examples of suitable epoxides are monoglycidyl compounds that may be described as

where R1 is chosen among groups such as hydrogen, non-substituted saturated or unsaturated C1-
C24 alkyl, substituted saturated or unsaturated C1-C24-alkyl, substituted or non-substituted aryl,
aliphatic or aromatic carbonyl, wherein the carbon chains of said compounds may optionally
include one or more of the elements oxygen, nitrogen, sulphur, silicon and boron, or Rl is chosen
among condensation products or addition products of one or more types of chemical compounds
such as acids, alcohols, phenols, amines, aidehyd s or epoxides.
Examples of suitable epoxides are furthermore compounds with epoxidized C=C double bonds
that may be described as

wherein R1 - R4 are chosen among groups such as hydrogen, non-substituted saturated or
unsaturated C1-C24 alkyl, substituted saturated or unsaturated C1-C24-alkyl, substituted or non-
substituted aryl, aliphatic or aromatic carbonyl, wherein the carbon chains of said compounds n
optionally include one or more of the elements oxygen, nitrogen, sulphur, silicon and boron, or

is chosen among condensation products or addition products of one or more types of chemical
compounds such as acids, alcohols, phenols, amines, aldehydes or epoxides
Examples of suitable acid derivatives are

where R1 is chosen among groups such as hydrogen, non-substituted saturated or unsaturated C1-
C24 alkyl, substituted saturated or unsaturated C1-C24-alkyl, substituted or non-substituted aryl,
aliphatic or aromatic carbonyl, wherein the carbon chains of said compounds may optionally
include one or more of the elements oxygen, nitrogen, sulphur, silicon and boron, or Rl is chosen
among condensation products or addition products of one or more types of chemical compounds
such as acids, alcohols, phenols, amines, aldehydes or epoxides, and
X is a suitable removable group such as halogen, substituted or non-substituted alkoxy, phenoxy,
amine, carboxylate, sulphonate, sulphinate, phosphonate or phosphinate.
Examples of suitable isocyanates may be described as

where R1 is chosen among groups such as hydrogen, non-substituted saturated or unsaturated C1-
C24 alkyl, substituted saturated or unsaturated C1-C24-alkyl, substituted or non-substituted aryl,
aliphatic or aromatic carbonyl, wherein the carbon chains of said compounds may optionally
include one or more of the elements oxygen, nitrogen, sulphur, silicon and boron, or R1 is chosen
among condensation products or addition products of one or more types of chemical compounds

such as acids, alcohols, phenols, amines, aldehydes or epoxides, and wherein the isocyanate group
may be blocked by means of known chemical substances.
In the crosslinking process and thus the curing process between particle forming condensation
products and more or less free amino groups at the surface of epoxy resins, addition products of
the following type are formed:

In the same manner addition products are formed when more or less free amino groups are
converted with isocyanates:

Thus, particle forming condensation products with more or (ess free amino groups at the surface
may also be used in the crosslinking process and thus the curing process of isocyanate-based
resins, which leads to the formation of so-called polyuretanes.
Preferred embodiments
A preferred embodiment of the invention s a hardener as defined by (III) wherein X=NR1 R2, R1 is
hydrogen and R2 is H-(HN-CH2- CH2-)m where m = 0-6, B is propylene, n = 1, and Y is ethoxy or
methoxy.
Another preferred embodiment of the invention is a hardener as defined by (III) wherein X=NR,
R2, R1 is hydrogen and R2 is phenyl, B is propylene, n = 1, and Y is ethoxy or methoxy.
Still another preferred embodiment of the invention is a hardener as defined by (III) wherein X=
NR1 R2, R1 is hydrogen and R2 is carbamoyl, B is propylene, n = 1, and Y is ethoxy or methoxy.
Still another preferred embodiment of the invention is a hardener as defined by (III) wherein X =
SH, B is propylene, n = 1, and Y is ethoxy or methoxy.
Still another preferred embodiment of the invention is a hardener as defined by (III) wherein X =
N=C=O, B is propylene, n = 1, and Y is ethoxy or methoxy.

Still another preferred embodiment of the invention is a hardener as defined by (III) wherein the
sol entirely or partly is prepared by controlled hydrolysis and condensation of bis (?-
trialkoxysilylpropyl)amine.
Still another preferred embodiment of the invention is a hardener as defined by (III) wherein the
sol entirely or partly is prepared by controlled hydrolysis and condensation of tris [3-
trialkoxysilylpropyl]isocyanurate.
The hardener of the invention may when convenient, also include at least one UV absorber, at least
one radical scavenger, at least one antioxidant, at least one dye or a pigment, at least one filler and/
or at least one additive.
According to another aspect the invention may also comprise mixtures comprising at least one of
the sol-gel based hardeners according to one of the above said aspects of the invention, and epoxy
resins and optionally additives such as antioxidants, light absorbing agents (UV absorbers), radical
scavengers, acid controllers, dyes, pigments, fillers and/ or other additives.
Examples
Preparation of particle forming condensation product
1. 250 g ?- aminopropyl triethoxysilane (y-APS, Crompton Corporation, USA) is placed in a
1000 ml round bottom flask with condenser and magnetic stirrer. A mixture of 73.5 g
butyldiglycol (BDG) and 28.5 g water is added. The mixture was heated in an oil bath to 110
°C under reflux for 45 minutes. The condenser is replaced by a distillation column and
volatile reaction products are removed at an oil bath temperature of 110 °C and a vacuum
gradient of from 1000 mbar - 20 mbar. The distillation is terminated when the pressure in the
round bottom flask has reached 20 mbar or less for 10 minutes. About 175 ml distillate was
collected. The reaction product is a clear, colourless liquid with Gardner Colour (according to Gardner Colour Scale/ ASTM D 1544) and a viscosity with 4-dodecylbenzene sulphonic acid in ethanol/ water (96 vol-% ethanol) showed that about
75% of the amino groups in the original ?-APS are available for protonation with 4-
dodecylbenzene sulphonic acid.
2. 250 g ?- aminopropyl triethoxysilane (?-APS, Crompton Corporation, USA) is placed in a
1000 ml round bottom flask with condenser and magnetic stirrer. A mixture of 73.5 g
butylglycol (BDG) and 28.5 g of water and 0.73 g Tinuvin 123 (Ciba Specialty Chemicals,
Switzerland) is added. The composition is heated in an oil bath at 110 °C under reflux for 45
minutes. The round bottom flask is replaced by a distillation column and volatile components
are removed at oil bath temperature 110 C and a vacuum gradient from about 1000 mbar - 20
mbar. The distillation is terminated when the pressure in the round bottom flask has reached

20 mbar or less for 10 minutes. About 172 ml of distillate was collected. The reaction
product is a clear colourless liquid with Gardner Colour = 1 (according to Gardner Colour
Scale/ ASTM D 1544) and viscosity acid in ethanol/ water (96% ethanol) showed that 75% of the amino groups of the original are
available for protonation with 4-dodecylbenzene sulfonic acid.
3. 250 g ?- aminopropyl triethoxysilane (?-APS, Crompton Corporation, USA) is placed in a
1000 ml round bottom flask with condenser and magnetic stirrer. A mixture of 73.5 g
butylglycol (BDG) and 28.5 g of water and 0.73 g Tinuvin 123 (Ciba Specialty Chemicals,
Switzerland) is added. The composition is heated in an oil bath at 110 °C under reflux for 45
minutes. The condenser is replaced by a distillation column and volatile components are
removed at oil bath temperature HOC and a vacuum gradient from about 1000 mbar - 20
mbar. The distillation is terminated when the pressure in the round bottom flask has reached
20 mbar or less for 10 minutes. About 175 ml of distillate was collected. To the still warm
reaction product is added a heated solution of 1.0 g Cyasorb UV-1164 (Cytec Inc., USA) in
10 ml cyclohexane (Cytek Inc., USA). Thereafter another distillation is performed as
described above until the pressure in the round bottom flask has reached 20 mbar or less for
10 minutes. The reaction product is a clear yellow liquid with Gardner Colour = 3 (according
to Gardner Colour Scale/ ASTM D 1544) and viscosity reaction product is a wax-like, crystalline yellow mass.
4. 885.6 g ?-aminopropyl triethoxysilane (?-APS, Crompton Corporation, USA) is placed in a
1000 ml round bottom flask with condenser and magnetic stirrer. A mixture of 389.3 g
butylglycol (BDG) and 93.6 g of water and 12.0 g Tinuvin 123 (Ciba Specialty Chemicals,
Switzerland) is added. The composition is heated in an oil bath at 110 °C under reflux for 45
minutes. The condenser is replaced by a distillation column and volatile components are
removed at oil bath temperature 110 °C and a vacuum gradient from about 1000 mbar - 20
mbar. The distillation is terminated when the pressure in the round bottom flask has reached
20 mbar or less for 10 minutes. About 536 g of distillate was collected. To the still warm
reaction product are added a heated solution of 12.0 g Cyasorb UV-1164 and 12.0 g Cyasorb
UV-2908 (Cytec Inc., USA) dissolved in 94 ml toluene. Thereafter another distillation is
performed as described above until the pressure in the round bottom flask has reached 20
mbar or less for 10 minutes. The reaction product is a clear yellow liquid with Gardner
Colour = 3 (according to Gardner Colour Scale/ ASTM D 1544) and viscosity 50 ° C. At 10 ° C the reaction product is a wax-like, crystalline yellow mass.
5. 597.8 g ?- aminopropyl triethoxysilane (?-APS, Crompton Corporation, USA) is placed in a
1000 ml round bottom flask with condenser and magnetic stirrer. A mixture of 262.5 g
butylglycol (BDG) and 63.2 g of water and 8.1 g Tinuvin 123 (Ciba Specialty Chemicals,

Switzerland) is added. The composition is heated in an oil bath at 110 °C under reflux for 45
minutes. The condenser is replaced by a distillation column and volatile components are
removed at oil bath temperature 110 C and a vacuum gradient from about 1000 mbar - 20
mbar. The distillation is terminated when the pressure in the round bottom flask has reached
20 mbar or less for 10 minutes. About 536 ml distillate was collected. To the still warm
reaction product is added a heated solution of 12.0 g Cyasorb UV-1164 (Cytec Inc., USA)
dissolved in 36 ml toluene. Thereafter another distillation is performed as described above
until the pressure in the round bottom flask has reached 20 mbar or less for 10 minutes. The
reaction product is a clear yellow liquid with Gardner Colour = 3 (according to Gardner
Colour Scale/ ASTM D 1544) and viscosity product is a wax-like, crystalline yellow mass.
Mixture of particle forming condensate product with commercial hardeners and
conversion of the mixture with commercial epoxy resins for test/plate preparation.
6. 100 g epoxy resin (commercially available reaction product from the conversion of 2,2-bis-(4-
hydroxyphenyl)-propane and epichlorohydrin, CY 219, Vantico AG, Switzerland) was
weighed in a beaker with a weight of an accuracy of 0.1 g. Then 50 g hardener (1:1 v/v
mixture of the sol from experiment 1 and HY 5160 from Vantico AG, Switzerland) was
added and the mixture was thoroughly stirred by hand. The resin was preheated to 40 °C,
while the hardener was at ambient temperature, i.e. about 23 °C. Thereafter the mixture was
placed in a hot cabinet at 40 C to facilitate air removal from the epoxy composition, i.e.
removal of small air bubbles. After some minutes the mixture was transferred to a 60 ml
disposable syringe and subsequently transferred to Petri dishes with internal diameter of 87
and 137 mm. The dishes had been waxed with a layer of slip wax from Vantico of the type
QV 5110. Subsequent this transferral lids were placed on the Petri dishes. The samples were
cured for one day (24 h) at room temperature. Thereafter the samples were demoulded and
post-cured for about 17 h at 70 °C. The samples were finally wrapped in paper and put into
plastic bags provided with zippers.
Different compositions of hardeners were prepared between particle-forming condensation
products in 3-5, and a commercially available low viscous, phenol free, modified,
cycloaliphatic polyamine hardener for epoxy resins (Aradur 2965, Vantico AG, Switzerland).
The different compositions are listed in table 1.


The such prepared hardener compositions were mixed with epoxy resins (commercially available
reaction product from the conversion of 2,2-bis-(4-hydroxyphenyl)-propane and epichlorohydrin
(Araldite GY 250, Vantico AG, Switzerland) in the same manner as in Example 6. The
compositions were cured to about 2 mm thick layers on plates of PVDF (polyvinylene fluoride).
The mixture ratios are shown in table 2.

Conversion of particle-forming condensation product with commercially available epoxy resins
for preparation of samples/ plates
8. 100 g epoxy resin (commercially available reaction product from the conversion of 2,2-bis-(4-
hydroxyphenyl)-propane and epichlorohydrin, CY 219, Vantico AG, Switzerland) was
weighed in a beaker with a weight of an accuracy of 0.1 g. Then 50 g hardener (sol prepared
in Example 1) was added and the mixture was thoroughly stirred by hand. The resin was
preheated to 40 °C, while the hardener was at ambient temperature, i.e. about 23 °C.

Thereafter the mixture was placed in a hot cabinet at 40 ° C to facilitate air removal from the
epoxy composition, i.e. removal of small air bubbles. After some minutes the mixture was
transferred to a 60 ml disposable syringe and subsequently transferred to Petri dishes with
internal diameter of 87 and 137 mm. The dishes had been waxed with a layer of slip wax
from Vantico of the type QV 5110. Subsequent this transferral lids were placed on the Petri
dishes. The samples were cured for one day (24 h) at room temperature. Thereafter the
samples were demoulded and post-cured for about 17 h at 70 °C. Finally, the samples were
wrapped in paper and put into plastic bags provided with zippers.
9. 100 g epoxy resin (commercially available reaction product from the conversion of 2,2-bis-(4-
hydroxyphenyl)-propane and epichlorohydrin, CY 219, Vantico AG, Switzerland) was
weighed in a beaker with a weight of an accuracy of 0.1 g. Then 50 g hardener (sol prepared
in Example 2) was added and the mixture was thoroughly stirred by hand. The resin was
preheated to 40 °C, while the hardener was at ambient temperature, i.e. about 23 °C.
Thereafter the mixture was placed in a hot cabinet at 40 ° C to facilitate air removal from the
epoxy composition, i.e. removal of small air bubbles. After some minutes the mixture was
transferred to a 60 ml disposable syringe and subsequently transferred to Petri dishes with
internal diameter of 87 and 137 mm. The dishes had been waxed with a layer of slip wax
from Vantico of the type QV 5110. Subsequent this transferral lids were placed on the Petri
dishes. The samples were cured for one day (24 h) at room temperature. Thereafter the
samples were demoulded and post-cured for about 17 h at 70 °C. Finally, the samples were
wrapped in paper and put into plastic bags provided with zippers.
10. 100 g epoxy resin (commercially available reaction product from the conversion of 2,2-bis-(4-
hydroxyphenyl)-propane and epichlorohydrin, CY 219, Vantico AG, Switzerland) was
weighed in a beaker with a weight of an accuracy of 0.1 g. Then 50 g hardener (sol prepared
in Example 3) was added and the mixture was thoroughly stirred by hand. The resin and the
hardener were preheated to 60 °C in a hot cabinet. Thereafter the mixture was transferred to a
60 ml disposable syringe and subsequently transferred to Petri dishes with internal diameter
of 87 and 137 mm. The dishes had been waxed with a layer of slip wax from Vantico of the
type QV 5110. Subsequent this transferral lids were placed on the Petri dishes. The samples
were cured for one day (24 h) at room temperature. Thereafter the samples were demoulded
and post-cured for about 17 h at 70 °C. Finally, the samples were wrapped in paper and put
into plastic bags provided with zippers.
11. 100 g epoxy resin (commercially available reaction product from the conversion of 2,2-bis-(4-
hydroxyphenyl)-propane, 2,2-bis-(4-hydroxyphenyl)-methane and epichlorohydrin, to which
was added low viscous epoxides for dilution (L 0166/ S700, Bakelite AG, Germany) was

weighed in a beaker with a weight of an accuracy of 0.1 g. Then 50 g hardener (sol prepared
in Example 1) was added and the mixture was thoroughly stirred by hand. The resin was
preheated to 40 °C, while the hardener was at ambient temperature, i.e. about 23 °C.
Thereafter the mixture was placed in a hot cabinet at 40 C to facilitate air removal from the
epoxy composition, i.e. removal of small air bubbles. After some minutes the mixture was
transferred to a 60 ml disposable syringe and subsequently transferred to Petri dishes with
internal diameter of 87 and 137 mm. The dishes had been waxed with a layer of slip wax
from Vantico of the type QV 5110. Subsequent this transferral lids were .placed on the Petri
dishes. The samples were cured for one day (24 h) at room temperature. Thereafter the
samples were demoulded and post-cured for about 17 h at 70 °C. Finally, the samples were
wrapped in paper and put into plastic bags provided with zippers
Conversion of commercially available hardeners with commercially available epoxy resins
for preparation of samples/ plate
12. 100 g epoxy resin (commercially available reaction product from the conversion of 2,2-bis-(4-
hydroxyphenyl)-propane and epichlorohydrin, CY 219, Vantico AG, Switzerland) was
weighed in a beaker with a weight of an accuracy of 0.1 g. Then 50 g hardener (HY 5160,
Vantico AG, Switzerland) was added and the mixture was thoroughly stirred by hand. The
resin was preheated to 40 °C, while the hardener was at ambient temperature, i.e. about 23 °C.
Thereafter the mixture was placed in a hot cabinet at 40 C to facilitate air removal from the
epoxy composition, i.e. removal of small air bubbles. After some minutes the mixture was
transferred to a 60 ml disposable syringe and subsequently transferred to Petri dishes with
internal diameter of 87 and 137 mm. The dishes had been waxed with a layer of slip wax
from Vantico of the type QV 5110. Subsequent this transferral lids were placed on the Petri
dishes. The samples were cured for one day (24 h) at room temperature. Thereafter the
samples were demoulded and post-cured for about 17 h at 70 °C. Finally, the samples were
wrapped in paper and put into plastic bags provided with zippers
Modification of more or less free amino groups at the surface of particle-forming condensation
products
13. 100 g reaction product from 11 is heated to 70 °C to obtain a clear liquid. Then 100 g
glycidyl-2-methylphenylether (CAS [2210-79-9]; Araldite DY-K, Vantico AG, Switzerland)is
added and the reaction mixture held at 70 °C for one hour. A clear yellow product is obtained
that is viscous gel at 10 °C and a low viscous liquid at 80 °C. This product reacts significantly
slower in a curing process with commercially available reaction products from the conversion
of 2,2-bis(4-hydroxyphenyl)-propane and epichlorohydrin than the reaction product from 11.

14. 100 g reaction product from 11 is heated to 70 °C to obtain a clear liquid. Then 150 g
glycidyf-2-methylphenylether (CAS [2210-79-9]; Araldite DY-K, Vantico AG, Switzerland)is
added and the reaction mixture heid at 70 °C for one hour. A clear yellow product is obtained
that is viscous gel at 10 °C and a low viscous liquid at 80 °C. In contradiction to the reaction
product from 11, this product does not react in a curing process with commercially available
reaction products from the conversion of 2,2-bis(4-hydroxyphenyl)-propane and
epichlorohydrin.
Characterisation and testing:
Sol particle size
The particle size of the sol was measured using the light scattering principle. A commercial
instrument, "Zetasizer 3" from Malvern, UK, was used for the determination of size distribution.
The size distribution was sharp and the average particle size was less than 5 nm for the sols

prepared according to Examples 1-3,
Abrasion properties
Abrasion properties were tested using a Universal Wear Testing Machine from Eyre/Bicere -
apparatus. The constant weight was 588g (3X load). A relatively large number of scratches were
made on a plate made in accordance with Example 9. On a plate made in accordance with
Example 4 the scratches are barely visible.
Scratch resistance/ abrasion properties as determined by to Erichsen test
The scratch resistance/ abrasion test was investigated by means of a hardness pen of Erichsen type
(Erichsen, Germany). The method is based on making a scratch with the hardness pen. The force
exerted during the test is controlled by a spring. The hardness value related to the force is read
from the hardness pen in Newton [N]. At least three parallel measurements are made to each
sample. It is recorded when the force does not provide visible scratches and at what force the first
visible scratch is obtained. The test was conducted on a series of plates prepared as described by
Example 8. It is shown that the force required to make scratches on plates made with modified
hardener, is at least 40 times greater than the force required to make scratches on the plates made
with commercial amine based hardeners. The results are given in table 3.


Accelerated ageing and measurement of colour/ brightness
The epoxy plates made in accordance with Example 14 were subjected to accelerated ageing
according to ISO 4892-3 for 426 hours. The test instrument was an ATLAS UVCON weather-o-
meter (Atlas Inc., USA) furnished with UVA-340 fluorescence lamps. The test cycle comprised 4
hours UV radiation at dry heating to 45 °C, 30 minutes of water sprinkling at 10-12 °C and 3 hours
and 30 minutes of condensation at 40 °C.
The colours of the plates were measured prior to the accelerated ageing and subsequent the
accelerated ageing according to ASTM 2244.
Colour measured in so-called outdoor light, D65, 10°
Reference standard White (33112035N)
Colour difference in ClE-lab DL, Da, Db and DE
Total colour change DE
Colour coordinates DL(white/black), Da(red/green) and Db(yellow/blue)
Typical results of the colour measurements are shown in table 4.


The brightness measurements were conducted according to ISO 2813. The results are shown in
table 5. Brightness was measured in one single spot. The apparatus is a Byk Gardner multi tri
gloss 20 °, 60 ° and 85 °. Due to the fact that brightness reflection at 60 provides more than 100%
brightness, table 5 shows values measured with an angle of incidence of 85 °. Typical results of
the colour measurements are shown in table 5.

It is evident that epoxy plates based on the hardener of the system according to the present
invention (Plate/ sample No. 1-IV) exhibit significantly less colour change and/ or loss of
brightness than do the epoxy plates not based on such a hardener (Plate/ sample No. V).
The brightness reduction is caused by chemical degradation of the plates. Thus, plates that
subsequent to accelerated ageing shows little or no brightness reduction have better qualifications
with respect to their ability to resist degradation from chemicals such as acids or basic liquids than
do plates that exhibit comparatively large brightness reduction.

WE CLAIM:
1. Hardener for curing of epoxy resins which produces materials with high
abrasion resistance, photostability and chemical resistance, characterized in
that the hardener comprises a sol prepared by controlled hydrolysis and
condensation of compounds of the type:
(X-B-)n Si(-Y)4-n
where n = 1 or 2, X = SH, -N=C=O, or NR1R2, R1, R2 being chosen from
hydrogen, saturated or unsaturated C1-C18-alkyl, substituted or non-
substituted aryl, formyl, aliphatic or aromatic carbonyl, carbamoyl, sulphonyl,
sulphoxyl, phosphonyl, sulphinyl, phosphinyl, while the carbon chains of said
compounds may include one or more of the elements oxygen, nitrogen,
sulphur, phosphorus, silicon and boron, and/or may include one or more
hydrolysable silane units or R1, R2 are chosen from condensation products or
addition products of one or more types or chemical compounds such as
acids, alcohols, phenols, amines, aldehydes or epoxides, and

B is a spacing group chosen from saturated or unsaturated C1-C18-alkylene,
substituted or non-substituted arylene, while the carbon chains of the stated
compounds may include one or more of the elements oxygen, nitrogen,
sulphur, phosphorus, silicon and boron and Y is chosen from hydrolisable
groups such as alkoxy, carboxyl, and halogen.
2. Hardener as claimed in claim 1, wherein the hardener also comprises at least
one UV-absorber.
3. Hardener as claimed in one of the preceding claims, wherein the hardener
also comprises at least one free radical scavenger.
4. Hardener as claimed in one of the preceding claims, wherein the hardener
also comprises at least one antioxidant.
5. Hardener as claimed in one of the preceding claims, wherein the hardener
also comprises at least one dye and/or pigment.
6. Hardener as claimed in one of the preceding claims, wherein the hardener
also comprises at least one filler.

7. Hardener as claimed in one of the claims 1-6, wherein X= NR1R2, R1 is
hydrogen and R2 is H-(HN-CH2- CH2-)m where m = 0-6, B is propylene, n = 1,
and Y is an ethoxy or methoxy.
8. Hardener as claimed in one of the claims 1-6, wherein X= NR1R2, R1 is
hydrogen and R2 is phenyl, B is propylene, n = 1, and Y is ethoxy or methoxy.
9. Hardener as claimed in one of the claims 1-6, wherein X= NR1R2,R1 is
hydrogen and R2 is carbamoyl, B is propylene, n = 1, and Y is ethoxy or
methoxy.
10. Hardener as claimed in one of the claims 1-6, wherein X = SH, B is
propylene, n = 1, and Y is ethoxy or methoxy.
11. Hardener as claimed in one of the claims 1-6, wherein X = -N=C=O, B is
propylene, n = 1, and Y is ethoxy or methoxy.
12. Hardener as claimed in one of the claims 1-6, wherein the sol is prepared
entirely or partly by controlled hydrolysis and condensation of bis (?-
trialkoxysilylpropyl)amine.

13. Hardener as claimed in one of the claims 1-6, wherein the sol is prepared
entirely or partly by controlled hydrolysis and condensation of tri[3-
(trialkoxysilylpropyl]isocyanurate.
14. Hardener as claimed in claim 1, wherein more or less free amino groups at
the surface of the particle-forming condensation product in the sol has been
entirely or partly converted with reactive compounds such as epoxides, acid
derivatives, blocked and non-blocked isocyanates and compounds of the type
R-X where X is a suitable atom or atom group that may be replaced and R is
an organic residue or a fraction of such residue.
15. Hardener as claimed in claim 14, wherein X is chosen among halogen,
substituted or non-substituted alkoxyl, phenoxyl, amine, carboxylate,
sulphonate, sulphinate, phosphonate and phosphinate.
16. Hardener as claimed in claim 14, wherein R is chosen among non-substituted
saturated and unsaturated C1-C24 alkyl, substituted saturated or unsaturated
C1-C24 alkyl, substituted or non-substituted aryl, aliphatic or aromatic
carbonyl, wherein the carbon chains of said compounds may optionally
include one or more of the elements nitrogen, sulphur, silicon and boron and
groups chosen among condensation products of one or more type of

chemical compounds such as acids, alcohols, phenols, amines, aldehydes
and epoksides.
17. Cured epoxy material, wherein it is manufactured from an epoxy resin and a
hardener as defined by claim 1.
18. Method for curing epoxyresins,
wherein
i) producing a stable sol by controlled hydrolysis and condensation of a
silane compound of the formula:
(X-B-)nSi(-Y)4-n
where n = 1 or 2, X = SH, -N=C=O, or NR1R2, R1, R2 being chosen from
hydrogen, saturated or unsaturated C1-C18-alkyl, substituted or non-
substituted aryl, formyl, aliphatic or aromatic carbonyl, carbamoyl, sulphonyl,
sulphoxyl, phosphonyl, sulphinyl and phosphinyl, while the carbon chains of
said compounds may optionally include one or more of the elements oxygen,
nitrogen, sulphur, phosphorus, silicon and boron, and/or may include one or
more hydrolysable silane units or R1, R2 are chosen from condensation
products or addition products of one or more types or chemical compounds
such as acids, alcohols, phenols, amines, aldehydes or epoxides, said silane
compound optionally being a modified one, and that

ii) the sol, subsequent to possible storage, is mixed with an epoxy resin so
that the latter is cured.
19. Method as claimed in claim 18, wherein unwanted reaction products from
step i), such as alcohols and water, are removed from the sol prior to step ii).
Hardener for curing of epoxy resins which produces materials with high abrasion
resistance, photostability and chemical resistance. The hardener comprises a
sol prepared by controlled hydrolysis and condensation of compounds of the
type:
(X-B-)n Si(-Y)4-n
where n = 1 or 2, X = SH, -N=C=O, or NR1R2, R1, R2 being chosen from
hydrogen, saturated or unsaturated C1-C18-alkyl, substituted or non-substituted
aryl, formyl, aliphatic or aromatic carbonyl, carbamoyl, sulphonyl, sulphoxyl,
phosphonyl, sulphinyl, phosphinyl, while the carbon chains of said compounds
may include one or more of the elements oxygen, nitrogen, sulphur, phosphorus,
silicon and boron, and/or may include one or more hydrolysable silane units, or
R1, R2 are chosen from condensation products or addition products of one or
more types or chemical compounds such as acids, alcohols, phenols, amines,
aldehydes or epoxides.
B is a spacing group chosen from saturated or unsaturated C1-C18-alkylene,
substituted or non-substituted arylene, while the carbon chains of the stated
compounds may optionally include one or more of the elements oxygen,
nitrogen, sulphur, phosphorus, silicon and boron. Y is chosen from hydrolisable
groups such as alkoxy, carboxyl, and halogen.

Documents:

00897-kolnp-2005-abstract.pdf

00897-kolnp-2005-claims.pdf

00897-kolnp-2005-correspondence.pdf

00897-kolnp-2005-description complete.pdf

00897-kolnp-2005-form 1.pdf

00897-kolnp-2005-form 18.pdf

00897-kolnp-2005-form 2.pdf

00897-kolnp-2005-form 26.pdf

00897-kolnp-2005-form 3.pdf

00897-kolnp-2005-form 5.pdf

00897-kolnp-2005-international publication.pdf

00897-kolnp-2005-letter patent.pdf

00897-kolnp-2005-reply first examination report.pdf


Patent Number 216843
Indian Patent Application Number 00897/KOLNP/2005
PG Journal Number 12/2008
Publication Date 21-Mar-2008
Grant Date 19-Mar-2008
Date of Filing 16-May-2005
Name of Patentee SINTEF
Applicant Address RICHARD BIRKELANDS VEI 2B,N-7466 TRONDHEIM, NORWAY
Inventors:
# Inventor's Name Inventor's Address
1 SIMON,CHRISTIAN TAASEN ALLE 13B N-0853 OSLO NORWAY
2 BEYLICH,JEST TRESCHOWSGATE 17B N-0470 OSLO NORWAY
3 WINDSLAND,KJELL TOSTRUP TERRASSE 7 0271 OSLO NORWAY
4 REDFORD,KEITH LIKOLLEN 70 N-1481 HAGAN NORWAY
5 MÄNNLE,FERDINAND FJORDEIEN 13 N-0139 OSLO NORWAY
6 GAARDER,RUNE H. FJELLSVINGEN 19 N-1472 FJELLHAMAR NORWAY
PCT International Classification Number C09D 163/00
PCT International Application Number PCT/NO2003/000342
PCT International Filing date 2003-10-16
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 20024990 2002-10-16 Norway