Note: Descriptions are shown in the official language in which they were submitted.
-1-
K-17809/1+2/+
Photosensitive mixture
The present invention relates to a liquid, photosensitive mixture, to a
process for the
polymerization of this mixture by means of actinic radiation, to a process for
the
production of three-dimensional articles from the liquid mixtures and to the
use of the
mixtures according to the invention for the production of photopolymerized
layers, in
particular of three-dimensional articles built up from several
photopolymerized layers.
As is known, radiation-sensitive, liquid resins or resin mixtures can be used
in a variety of
ways, for example as coating agents, adhesives or photoresists. In principle,
liquid resins
or resin systems should generally also be suitable for the production of three-
dimensional
articles by the stereolithographic process described in US Patent 4,575,330,
but some
resins prove to be too viscous, while others in turn are insufficiently light-
sensitive or are
subject to an excessive shrinking process when they are cured. The strength
properties of
the mouldings or articles composed of photo-cured resins also often leave
something to be
desired.
As is known, complicated three-dimensional articles can be produced from
liquid,
light-sensitive resins by means of the stereolithographic process. Articles of
this type are
built up in layers, each new curable layer of resin being firmly attached to
the preceding
pre-cured layer by preliminary curing by means of UVNIS light. The overall
build-up of
the three-dimensional article can, as is known, be accomplished by a computer-
controlled
process.
In recent years there has been no lack of attempts to develop resin systems
which can be
employed for the stereolithographic process. In Rev. Sci. Instrum. 52 (11)
1170-1173
(1981), H. Kodama discloses, under the tradename "Tevista", a liquid, photo-
curable resin
mixture consisting of an unsaturated polyester, acrylic acid esters, styrene,
a
polymerization initiator and a sensitizer. For the stereolithographic process,
this resin
system has the disadvantage that the photosensitivity is insufficient and the
so-called
green strength of articles pre-cured by laser beams is relatively low.
The stereolithographic process is described in more detail in US Patent
4,575,330, in
which the liquid resin employed is a modified acrylate defined in the
description as
"Potting Compound 363". Resin mixtures of this type are disclosed in US Patent
4,100,141. They too have the disadvantage that they are insufficiently
photosensitive and
require long times for the production of three-dimensional articles by the
stereolithographic process.
It is therefore understandable that exacting requirements are set for resins
which are to be
employed in stereolithographic processes. For example, they must have a
viscosity
suitable for the apparatus in which they are processed. The photosensitivity
of the resin
system should be so constituted that the ratio between radiation energy used
and depth of
penetration achieved into the liquid photosensitive resin mixture, in the
course of which
the components concerned solidify, is within reasonable limits. This means
that, in the
case of a resin or resin mixture suitable for the stereolithographic process,
the highest
possible depth of curing should be obtained by means of little radiation
energy, together
with, at the same time, a high degree of polymerization and a good green
strength.
In the process of successive polymerization of thin layers, such as is used in
the
stereolithographic process, usually none of these layers is completely cured.
The
incompletely cured article is described as a green product, and the modulus of
elasticity
and the tensile strength of this green product are also described as green
strength.
Normally, the green product is then cured by means of UV/VIS light, for
example by
means of a mercury vapour or xenon arc lamp. The green strength of a component
is
therefore an important parameter, since articles having a low green strength
can undergo
deformation under their own weight or they can sag or subside during curing. A
further
requirement for resin systems which are to be employed in stereolithographic
processes is
as small as possible a volume shrinkage in the transition from the liquid
state into the
laser-cured state. In the technology of stereolithography, the so-called "curl
factor" is
quoted as a process-specific measure of shrinkage-induced deformation. A curl
factor of 1
indicates that no shrinkage-caused deformation occurs. In practice, curl
factors up to
values of about 4 are measured, but only resins having a curl factor of 1-1.5
are suitable
for a stereolithographic process.
It has now been found that a liquid resin mixture consisting of several
mono(meth)acrylates and di(meth)acrylates differing from one another, which
additionally
contains a urethane (meth)acrylate and a monomeric or oligomeric
di(meth)acrylate based
-3-
on bisphenol A or bisphenol F can be employed for the stereolithographic
process and
produces, in the course of preliminary curing by means of laser beams, green
products
distinguished by a high green strength and a low curl factor. The articles
obtained by
complete curing have good mechanical properties, are rigid-elastic and thereby
permit
after-treatment of the article, such as grinding of the surface, incorporation
of special
components, for example plug-in connections, or even further processing by
machining.
The present invention therefore relates to a liquid, photosensitive mixture
containing
a) 5-25 % by weight of a monomeric aliphatic or cycloaliphadc di(meth)acrylate
having a
molecular weight (MW) of not more than 800,
b) 0-15 % by weight of a monomeric poly(meth)acrylate having a functionality
of at least
3 and an MW of not more, than 600,
c) 0-20 % by weighs of a mono(meth)acrylate or a mono-N-vinyl compound having
an
MW of not more than 500,
d) 20-60 % by weight of a urethane (meth)acrylate having a functionality of 2
to 4 and an
MW of 500 to 10,000,
e) 10-50 % by weight of a monomeric or oligomeric di(meth)acrylate based on
bisphenol
A or bisphenol F,
f) 0.1-10 % by weight of a photoinitiator and
g) 0-5 % by weight of customary additives,
the proportion of the components a) to g) together being 100 % by weight.
The mixture according to the invention preferably contains
a) 5-15 % by weight of a monomeric aliphatic or cycloaliphatic
di(meth)acrylate,
b) 5-10 % by weight of a monomeric poly(meth)acrylate,
c) 1-15 % by weight of a mono(meth)acrylate,
d) 30-50 % by weight of a urethane (meth)acrylate,
e) 30-50 % by weight of a di(meth)acrylate based on bisphenol A or bisphenol
F,
f) 0.5-7 % by weight of a photoinitiator and
g) 0.01-3 % by weight of an additive.
Examples of suitable compounds of the component (a) are the diacrylate and
dimethacrylate esters of aliphatic or cycloaliphatic diols, such as 1,3-
butylene glycol,
1,4-butanediol, neopentyl glycol, 1,6-hexanediol, diethylene glycol,
triethylene glycol,
~~~ ~4~
-4_
tetraethylene glycol, polyethylene glycol 400, polyethylene glycol 600,
tripropylene
glycol, ethoxylated or propoxylated neopentyl glycol, 1,4-
dihydroxymethylcyclohexane,
2,2-bis-(4-hydroxycyclohexyl)-propane or bis-(4-hydroxycyclohexyl)-methane.
It is preferable to use aliphatic di(meth)acrylates, in particular those
having an MW of 200
to 500, as the compound of the component (a).
Examples of suitable compounds of the component (b) are tri-, tetra- and penta-
acrylates
or tri-, tetra- and penta-methacrylates of the formulae I, II and III
Rt -CH2-C--ECH2 -R2)3 (I)~
CH2- ~ -~CH2-RZ)2
(II) and
CHz--CF-I3 2
R2-~'~H2-R2)2 (~I)9
in which Rt is a hydrogen atom, methyl, hydroxyl or a radical of the formula
IV
-O CH2 ~ --(CH2-R2)2
(IV)
CH~-OH
and R2 is a radical of the formula V
O Ra
_° p~~2 ~- ~ ~---C~H
2 ()
R3
in which n is zero or a number from 1 to 3 and R3 and R4 independently of one
another are
-5-
each a hydrogen atom or methyl.
Compounds of the formulae I to III which are particularly preferred are those
of the
formula I in which Rt is a methyl group or a radical of the formula IV and R2
is a radical
of the formula V in which n is zero.
The following are examples of compounds of the component (b) which can be
employed:
1,1,1-trimethylolpropane triacrylate or methacrylate, ethoxylated 1,1,1-
trimethylolpropane
triacrylate or trimethacrylate, pentaerythritol tetraacrylate,
monohydroxypentaerythritol
triacrylate or methacrylate or monohydroxydipentaerythritol pentaacrylate or
methacrylate. Compounds of this type are known and some are obtainable
commercially,
for example from the SARTOMER Company under the product names SR-295, SR-350,
SR-351, SR-367, SR-399, SR-444 and SR-454.
In particular, the compounds of the component (b) have an MW of 250 to 500.
The following compounds can be present for example as the component (c) in the
mixtures according to the invention: allyl acrylate, allyl methacrylate,
methyl, ethyl,
n-propyl, n-butyl, isobutyl, n-hexyl, 2-ethylhexyl, n-octyl, n-decyl and n-
dodecyl acrylate,
methyl, ethyl, n-propyl, n-butyl, isobutyl, n-hexyl, 2-ethylhexyl, n-octyl, n-
decyl and
n-dodecyl methacrylate, 2-hydroxyethyl, 2-hydroxypropyl and 3-hydroxypropyl
acrylate,
2-hydroxyethyl, 2-hydroxypropyl and 3-hydroxypropyl methacrylate, 2-
methoxyethyl,
2-ethoxyethyl, 2-ethoxypropyl and 3-ethoxypropyl acrylate, tetrahydrofurfuryl
methacrylate, 2-(2-ethoxyethoxy)-ethyl acrylate, cyclohexyl methacrylate, 2-
phenoxyethyl
acrylaie, glycidyl acrylate and isodecyl acrylate and also, as a mono-N-vinyl
compound,
N-vinylpyrrolidone or N-vinylcaprolactam. Products of this type are also known
and some
are available commercially, for example from the SARTOMER Company.
The compounds of the component (c) preferably have an MW of 50-300.
The urethane acrylates used as the component (d) in the mixtures according to
the
invention are known to those skilled in the art and can be prepared in a known
manner, for
example by reacting a hydroxyl-terminated polyurethane with acrylic acid or
methacrylic
acid to give the corresponding urethane acrylate, or by reacting an isocyanate-
terminated
grepolymer with hydroxyalkyl acrylates or methacrylates to give the urethane
acrylate.
Appropriate processes are disclosed, for example, in the published EP Patent
Applications
~'~~~ ~~.
-6-
114,982 and 133,908. The molecular weight of such acrylates is generally
within the range
from 400 to 10,000, preferably between 500 and 7000.
Urethane acrylates are also available commercially and are offered, for
example, under the
name EBECRYL~ by UCB, under the name Uvithane~ by Morton Thiokol or under the
product names SR 9504, SR 9600, SR 9610, SR 9620, SR 9630, SR 9640 and SR 9650
by
the SARTOMER Company.
It is preferable to employ, as urethane acrylates, those which have an MW of
500-7000
and have been prepared from aliphatic starting materials.
Diacrylates based on bisphenol A and bisphenol F which can be employed as the
component (e) are both the bisphenol A diacrylates and dimethacrylates and
bisphenol F
diacrylates and dimethacrylates and the diacrylates or dimethacrylates of
alkoxylated,
preferably ethoxylated or propoxylated, bisphenol A or F. The acrylates
obtainable by
reacting bisphenol A or bisphenol F diglycidyl ether with (meth)acrylic acid
are also
suitable. Monomeric or oligomeric di(meth)acrylates of this type are also
known and some
are available commercially, for example from the SARTOMER Company under the
product name SR-348 for ethoxylated bisphenol A dimethacrylate and under the
product
name SR-349 for ethoxylated bisphenol A diacrylate. It is preferable to use
the
di(meth)acrylates of bisphenol A or F and of ethoxylated bisphenol A or of
ethoxylated
bisphenol F as the component (e).
In particular, the compounds of the component (e) have an MW of 300-1000.
Any type of photoinitiator which forms free radicals when irradiated suitably
can be
employed as the component F in the mixtures according to the invention.
Typical
compounds of known photoinitiators are benzoins, benzoin ethers, such as
benzoin,
benzoin methyl ether, benzoin ethyl ether and benzoin isopropyl ether, benzoin
phenyl
ether and benzoin acetate, acetophenones, such as acetophenone,
2,2-dimethoxyacetophenone and 1,1-dichloroacetophenone, benzil, benzil ketals,
such as
benzil dimethyl ketal and benzil diethyl ketal, anthraquinones, such as
2-methylanthraquinone, 2-ethylanthraquinone, 2-tent-butylanthraquinone,
1-chloroanthraquinone and 2-amylanthraquinone, triphenylphosphine,
benzoylphosphine
oxides, for example 2,4,6-trimethylbenzoyldiphenylphosphine oxide {Luzirin
TPO),
benzophenones, such as benzophenone and 4,4'-bis-(N,1V'-dimethylamino)-
benzophenone,
-7-
thioxanthones and xanthones, acridine derivatives, phenazine derivatives,
quirioxaline
derivatives or 1-phenyl-1,2-propanedione 2-O-benzayl oxime, 1-aminophenyl
ketones or
1-hydroxyphenyl ketones, such as 1-hydroxycyclohexyl phenyl ketone, phenyl
1-hydroxyisopropyl ketone and 4-isopropylphenyl 1-hydroxyisopropyl ketone, all
of
which constitute known compounds.
Particularly suitable photoinitiators, which are generally used in combination
with a HeCd
laser as the radiation source, are acetophenones, such as 2,2-
dialkoxybenzophenones, and
«-hydroxyphenyl ketones, for example 1-hydroxycyclohexyl phenyl ketone or
2-hydroxyisopropyl phenyl ketone (= 2-hydroxy-2,2-dimethylacetophenane).
Another class of photoinitiators (f), which are usually employed when argon
ion lasers are
used, are the benzil ketals, for example benzil dimethyl ketal. In particular,
an
«-hydroxyphenyl ketone, benzil dimethyl ketal or
2,4,6-trimethylbenzoyldiphenylphosphine oxide is used as the photoinitiator.
Another class of suitable photoinitiators (f) is constituted by the ionic dye-
counter ion
compounds which are capable of absorbing actinic radiation and producing free
radicals
which initiate the polymerization of the acrylates (a) to (e) or the mono-N-
vinyl compound
(c). The mixtures according to the invention containing ionic dye-counter ion
compounds
can be cured in a fairly variable manner in this way with visible light within
the adjustable
wavelength range of 400-700 nm. Ionic dye-counter ion compounds and their mode
of
action are known, for example from EP-A-0,223,587 and US Patents 4,751,102;
4,772,530
and 4,772,541. Examples of suitable ionic dye-counter ion compounds which may
be
mentioned are the anionic dye-iodonium ion complexes, the anionic dye-pyrylium
ion
complexes and, especially, the cationic dye-borate anion,compounds of the
formula VI
RS\ / R7
B~ X c~n~
R6 R8
in which X+ is a cationic dye and R5, R6, R~ and R8 independently of one
another are each
an alkyl, aryl, alkaryl, allyl, aralkyl, alkenyl or alkinyl group, an
alieyclic group or a
saturated or unsaturated hetexocyclic group.
_g_
As is known, the photoinitiators are added in effective amounts, ie. in
amounts of about
0.1 to about 10 % by weight, relative to the total amount of the mixture. If
the mixtures
according to the invention are used for stereolithographic processes in which
laser
radiation is normally employed, it in essential that the absorption capacity
of the mixtures
is so adjusted by means of the type and concentration of the photoinitiator
that the depth of
curing at normal laser speed is approximately 0.1 to 2.5 mm.
The mixtures according to the invention can also also contain different
photoinitiators
which have a different radiation sensitivity in relation to the radiation of
emission lines of
different wavelengths. This achieves, for example, better utilization of a
UV/VIS light
source which radiates emission lines of different wavelengths. It is
advantageous in this
case if the various photoinitiators are so chosen and employed in such a
concentration that
a uniform optical absorption is produced in the case of the emission lines
used.
If desired, the customary additives, for example stabilizers, such as UV
stabilizers,
polymerization inhibitors, mould release agents, wetting agents, flow control
agents,
sensitizers, anti-sedimentation agents, surface-active agents, dyes, pigments
or fillers can
be added to the mixtures according to the invention.
The mixtures according to the invention can be prepared in a known manner, for
example
by premixing individual components and subsequently mixing these premixes or
by
mixing all the components by means of customary devices, such as stirred
vessels, in the
absence of light and, if appropriate, at a slightly elevated temperature.
The photosensitive mixtures according to the invention can be polymerized by
irradiation
with actinic light, for example by means of electron or X-ray beams or UV or
VIS light,
ie. by means of radiation within the wavelength range from 280 to 650 nm.
Laser radiation
from HeCd, argon ions or nitrogen ions and also metal vapour and NdYAG Iasers
of
multiplied frequency are particularly suitable. It is known to those skilled
in the art that
the suitable photoinitiator must be selected and, if appropriate, sensitized
for each light
source selected. It has been found that the depth of penetration of the
radiation into the
composition to be polymerized and the rate of working are directly correlated
with the
absorption coefficient and the concentration of the photoinitiator. In
stereolithography it is
preferable to employ photoinitiators which induce the highest number of free
radicals
formed and make possible the greatest depth of penetration of radiation into
the
-9-
compositions to be polymerized.
The invention therefore also relates to a process for polymerizing the
mixtures according
to the invention by irradiating them with actinic light.
The mixtures according to the invention are liquids having a viscosity of
about 300 to
about 10,000 mPa.s at 30°C, preferably 500 to 5000 mPa.s and
particularly 500 to 2500
mPa.s. Surprisingly, the mixtures according to the invention have, for a high
light
sensitivity, a low curl factor and a high green strength after precuring by
means of laser
radiation, which is particularly important in the case of stereolithographic
processes. After
complete curing, the shaped articles prepared from the mixtures according to
the invention
have a high strength at an adequate elasticity and are therefore rigid-
elastic.
The invention also relates to a process for the production of three-
dimensional articles
from the liquid mixtures according to the invention by means of
stereolithographic
processes in which the surface of a layer of the liquid mixture according to
the invention is
irradiated either as the whole surface or in a predetermined pattern, by means
of a ~JVV/VIS
light source, so that a layer is solidified in a desired layer thickness in
the irradiated areas,
then a new layer of the mixtures according to the invention is foixned on the
solidified
layer, and this is also irradiated either as the whole surface or in a
predetermined pattern,
and, by repeated coating and irradiation, three-dimensional articles composed
of several
solidified layers adhering to one another are obtained.
It is preferable to use a laser beam which is preferably computer-controlled
as the
radiation source in this process.
If the mixtures according to the invention are employed as coating agents,
clear and hard
coatings are obtained on wood, paper, metal, ceramics or other surfaces. The
coating
thickness can be varied very much and can be from about 1 wan to about 1 mm.
Relief
images for printed circuits or printing plates can be produced direct from the
mixtures
according to the invention by izradiating the mixtures, for example by means
of a
computer-controlled laser beam of suitable wavelength or using a photomask and
a
corresponding light source.
It is preferable to use the mixtures according to the invention for the
production of
photopolymerized layers, particularly in the form of three-dimensionai
articles built up
- to -
from several solidified layers adhering to one another.
The curl factor is determined on test specimens produced by stereolithographic
processes,
the deformation of a self supporting part of the test specimen being
determined by
shrinkage. The curl factor is the xatio of the height of a deformed, fixed
segment of the test
specimen to the height of the non-deformed segment. A ratio of 1 thus means
that no
shrinkage has taken place, and values of up to 1.5 represent acceptable
properties in
respect of shrinkage and deformation.
The mechanical properties of the article cured by means of laser radiation
(green strength)
and of the article obtained by after-curing are measured on an Instron 1112
tensile test
machine, using ribbons 45.7 mm in length and having a cross-section of 0.38 x
0.51 mm as
test specimens.
Example 1: 39.75 g of ethoxylated bisphenol A diacrylate (MW = 424, product SR-
349 of
the SARTOMER Company) are mixed at 40°C with 40.02 g of urethane
acrylate (MW =
1700, product SR 9504 of the SARTOMER Company), 3.25 g of 1,1,1-
trimethylolpropane
triacrylate (MW = 408), 12.99 g of 1,4-butanediol diacrylate (MW = 198) and 4
g of
1-hydroxycyclohexyl phenyl ketone. The resulting homogeneous liquid mixture
has a
viscosity of 1510 mPa.s at 30°C. The curl factor of a three-dimensional
shaped article
built up from individual layers (layer thickness = 0.305 mm) and prepared with
an HeCd
laser is 1.05. The so-called green shaped article, cured by means of laser
radiation, has an
elastic modulus of 20 N/mm2, a tensile strength of 2.4 N/mm2 and an elongation
at break
of 13 %. After the green shaped article has been cured for 30 minutes under
UV/VIS light
by means of an Hg lamp, the green strength is 1500 N/mm2, the tensile strength
is 40
N/mm2 and the elongation at break is 7 to 19 %.
Examples 2-7: Mixtures are prepared as in Example 1 by mixing the components
indicated
in Table 1 below and are processed to give three-dimensional shaped articles
under the
conditions indicated in Example 1. The properties of the shaped articles
obtained are also
shown in Table
1.
-11-
Table 1:
Example 2 3 4 5 6 7
Pentaerythritol tetraacrylate
(M5V = 352; SR-295) 3.60 2.88 3.61 2.89 - -
[g]
Trimethylol propane
triacrylate
(MW = 296; SR-351) - - - - 4.06 3.25
[g]
1,4-Butanediol diacrylate
(MW =198; SR-213) [g] 12.1512.97- - 12.1712.99
Diethylene glycol diacrylate
(MW = 214; SR-230) - - 13,1814,07- -
[g]
Urethane acrylate
(MW =1700; SR-9504) 40.5040.4039.4539.2840.0240.02
[g]
Ethoxylated
bisphenol A diacrylate
(MW = 424; SR-349) 39.7539.7539.7539.7539.7539.75
[g]
1-Hydroxycyclohexyl 4.00 4.00 4.00 4.00 4.00 4.00
phenyl
ketone [g]
Viscosity at 30C [mPa 1720 1650 1870 1750 1650 1510
~ s]
Mechanical properties
after laser curing:
Elastic modulus [N/mm2]30 25 50 50 15 18
Tensile strength [N/mm2]3.5 3.3 7.3 7.3 2.8 2.4
Elongation at break 14 12 15 15 12 13
[%]
curl factor ~ x) 1.01 x) ~ x)
1.0 1.0
Mechanical properties
after UV/VIS curing:
Elastic modulus [N/mm2]1500 1500 1700 1400 1400 1400
Tensile strength [N/mm2]55 50 50 35 40 40
Elongation at break 10-1510-1514-2010-225-15 5-10
[%]
x) not measured
- 12-
Examples ~-13: Mixtures are prepared as in Example 1 by mixing the components
indicated in Table 2 below and are processed to give three-dimensional shaped
articles
under the conditions indicated in Example 1. The properties of the shaped
articles
obtained are also shown in Table 2.
-13-
Table 2:
Example 8 9 10 11 12 13
Pentaerythritol tetraacrylate
(MW = 352; SR-295) 5.89 5.43 3.76 3.64 6.04 3.92
[g]
1,4-Butanediol diacrylate
(MW = 198; SR-213 [g] 9.94 9.16 12.6812.2710.196.61
Ethoxylated
bisphenol A diacrylate
(MW = 424; SR-349) 39.7539.7539.7539.7539.7539.75
[g]
1-Hydroxycyclohexylphenyl4.00 4.00 4.00 4.00 4,00 4.00
ketone
[gl
SR-9503 40.42
SR-9505 41.66
U-782 39.81
U-892 40.34
PM-6162 40.03
PM6184 45.72
Viscosity at 30C [mPa 4600 5400 6700 3400 3000 6450
~ s]
Mechanical properties
after laser curing:
Elastic modulus (N/mm2]20 43 9 14 9 58
Tensile strength [N/mm2]5 6 2 4 2 8
Elongation at break 50 33 33 38 28 43
[%]
Mechanical properries
after UV/VIS curing:
Elastic modulus [N/rnm2]340 560 215 270 196 625
Tensile strength [N/mm~]41 55 32 32 22 57
Elongation at break 46 16 41 37 19 15
[%]
~02~~~:~
-14-
SR-9503: Linear urethane acrylate made by SARTOMER;
MW = 2000,
viscosity = 2000 Pa.s at 21C.
SR-9505: Urethane acrylate made by SARTOMER; MW =1250,
viscosity: 145
Pa.s at 38C.
U-782: Uvithane 782, a urethane acrylate made by
Morton Thiokol Inc.,
double bond equivalent = 2400, viscosity =
800-1600 Pa.s at 49C.
U-892: Uvithane 892, a urethane acryilate made by
Morton Thiokol Inc.,
double bond equivalent = 1800, viscosity 410
Pa.s at 49C.
PM-6162: Photomer 6162, a linear urethane acrylate
made by Lanla~o, MW =
5000.
PM-6184: Photomer 6184, a trifunctional urethane acrylate
made by Lankro,
MW = 1800.
Examples 14-25: Mixtures are prepared as in Example 1 by mixing the components
indicated in Table 3 below and are processed to give three-dimensional shaped
articles
under the conditions indicated in Example 1. The properties of the shaped
articles
obtained are also shown in Table 3.
-15-
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-17-
SC-961: Aliphatic urethane diacrylate made by SARTOMER;
MG = 1850, viscosity = 81 Pas at 60°C.
SC-964: Aliphatic urethane diacrylate made by SARTOMER;
MG = 1300, viscosity = 21 Pas at 60°C.
SC-965: Aliphatic urethane diacrylate made by SARTOMER;
MG = 1500, viscosity =12 Pas at 60°C.
SR-9504: Aliphatic urethane diacrylate made by SARTOMER;
MG = 1700, viscosity =167 Pas at 21°C.
LR-8765: Diacrylate of butanediol diglycidylether made by BASF;
11~IG = 346.
CL-959: Monofunctional acrylate made by SNPE;
MG = 185.
SR-209: Tetraethylene glycol dimethacrylate made by SARTOMER;
MG = 330.
SR-348: Ethoxylated bisphenol A dimethacrylate made by SARTOMER;
MG = 452.
SR-349: Ethoxylated bisphenol A diacrylate made by SARTOMER;
MG = 424.
