Note: Descriptions are shown in the official language in which they were submitted.
2 t S 7 ~ & 5 PCT~EP94/02314
W -CURABLE BLOCK COPOLYMER COMPOSITION
The present invention relates to a W -curable block copolymer
composition. More specifically, the present invention relates to a
W -curable block copolymer composition for adhesives, sealants and
coatings comprising an elastomeric block copolymer and at least one
photoinitiator.
From PCT application No. WO 88/01281 a radiation curable
rubber-based pressure-sensitive adhesive composition is known
comprising at least one elastomeric rubber-based adhesive and a
polythiol as the cross-linking agent. This composition can be cured
by exposure to either electron beam radiation or W irradiation. In
the latter case, the additional presence of a photoinitiator is
required. The presence of a cross-linking agent, in particular a
polythiol, is taught to be essential for obtaining a cured
pressure-sensitive adhesive composition having good adhesion
properties and elevated temperature shear.
~owever, it would be attractive for economical and processing
reasons to reduce the number of components and still obtain a cured
adhesive composition having excellent properties, also at elevated
temperatures.
U.S. Patent No. 5,093,406 discloses a pressure-sensitive
adhesive comprising a free radical cured product formed by e.g. W
curing of a mixture containing:
(a) 15-60 parts by weight (pbw) of an unsaturated elastomer
component, suitably comprising styrene-isoprene diblock and
styrene-isoprene-styrene triblock copolymers,
(b) 85-40 pbw of a hydrogenated styrene based tackifying resin,
(c) 0-15 pbw of a reinforcing resin for the polystyrene endblock
of the elastomer component, and
(d) 0-10 pbw of a polythiol cross-linking agent.
W O 95/02640 .~ t ~ ~ ~ $5~ PCT~EP94/02314
Although the presence of a polythiol cross-linking agent is left
optional, it is clearly a preferred embodiment, which for instance
becomes readily apparent from the working examples, where only
compositions cont~ining a polythiol cross-linking agent are
described.
Hence, the need for a W -curable composition, which does not
require the presence of a cross-linking agent for an effective
curing and which can be suitably applied in e.g. hot melt adhesive
compositions, still remains.
Often, rubber-based hot melt adhesive, sealant and coating
compositions which do not contain any cross-linking agent, need to
be cured in an atmosphere containing as little oxygen as possible.
Upon exposure to W irradiation namely, the aliphatic double bonds
present in the rubber will open thus forming free radicals. The
various rubber polymer chains cont~ining free radicals along the
polymer chains interact with each other through said free radicals
as a result of which the desired cross-linking is accomplished.
However, the free radicals also readily react with oxygen to form
peroxides. It will be appreciated that-the formation of such
peroxides seriously hampers the cross-linking reaction.
Consequently, curing of rubber based compositions which do not
contain any cross-linking agent is conveniently performed in an
inert gas atmosphere, most suitably in a nitrogen atmosphere. It
will be understood that the requirement of an oxygen-poor
atmosphere seriously hampers the commercial development of UV
curing of rubber-based hot melt adhesives, sealants and coatings
which are free of cross-linking agent.
It would therefore be advantageous if W curing could be
performed in an atmosphere, wherein oxygen is present in minor
traces up to normal amounts, i.e. from about as little as l volume
% to the normal value in air of about 21 volume %. From a
commercial as well as an economical point of view it is highly
attractive to operate in relatively oxygen rich atmospheres, as no
expensive equipment and specific precautions are necessary to
ensure an oxygen-free atmosphere.
~ ~Pat~nt~r.~lir-ti~nNo.rcT~4lo2il~
~ru~k~xempla~ 2l67l85 ~
-- 3
:lence, it is an objecl of the present inven~-c~ to provide a
b __k copolymer composition which can be effec_:-e:y cured by
exp3sure to UV radiation wi-hout using any cross-:_n.king agent.
I- addition, it is an objec~ of the present inve~ on to provide a
W --urable hot melt adhesive, sealant or coatins --~position which
dces not require the presence of any cross-link -- ~gent and which
car. be readily cured in an oxygen-containing at~cs_nere.
Accordingly, the prescnt invention relates _~ ~ JX-curable
b:-ck copolymer composition comprising:
'a) 100 parts by weight (pbw~ of a multiarme~ lock
copolymer comprising at least one polyr.e- biock A
derived from a monovinyl aromatic com?c_nc and at least
one polymer block 3 derived from a con -_gated diene,
wherein:
- the content of monovinyl aromatic ~o.m?ound is in the
range of from S to 50~ by weight -ase on the total
weight of block copolymer;
- each block A has an apparent molec_lar weight in the
range of from 1,000 to 50,000; anc
- each block B has an apparent molec_ia_ weight in the
range of from 10,000 to 250,000; ar^
(b) from 0.5 to 30 pbw, preferably from 5 =: 20 pbw, of at
least one photoini.iator,
characterised in that the multi-armed block ^_?olymer has the
structure according to any one of the genera: _ormulae:
(AB)nX, (8A)nX, (ABA)nX, (BAB)nX or (AB ? B)qX~
wherein A is a polymer block derived from a .~onovinyl aromatic
compound, wherein B is a polymer block derived from a
conjugated diene, wherein n represents an i-~eger of 2 or
higher and p and q represent an integer of : o- higher~and
wherein X is the residue of the coupling agen~ used, that at
least one photoinitiator is used, containirg a carbonyl group
whlch is directly bound to at least one ar^r.at-c ring
structure;
AMENDED S~ET
JO2~X~
T 'PatentAr~liri~ No.PCT~P94/02314
2 1 6 7 1 8 5
that said somposition is free Crom ~ c:oss-linking agent and
that it is curable ln an oxygen-con=ai.ing atmosphere.
With the expression "apparent molec~ia- weight" as used
throughout this description, the mo_ecuiar weight as
determined by Gel Permeation Chroma=ography using polystyrene
calibration standards is meant.
AMENDED S~
~ In Idl Patent~;, No. PC.T/EP94/02314
2167185
(4)
Commor coupling agents are for instance divinyl be-.--ne,
silic^n tetrachloride, gamma glycidoxy-propyl-trime--cxyl-
silane and dibromoethane. A preferred block copol~...e- has
the general formula (AB)nX with A and B as previous:y
define~, n representing an integer in the range of --^m 3 to
20, pr-ferably 4 to 12, and X representing a coupl~ agent
residue, preferably t~e residue of divinyl benzene. The
multi--rmed block copolymers may be prepared by cou-::ng
living sequentially prepared intermediate polymer ~ ns by
using any conventional coupIing techniques, such as
e.g. d sclosed in U.S. Patents Nos. 3,231,635i 3,43:,323;
3,251,'05; 3,390,207; 3,598,887 and 4,219,627.
The monovinyl aromatic compound may be selected frcm
styrene, a-methylstyrene, o-methylstyrene, p-methy_s-yrene,
p-tert-Dutyl-styrene, 1,3-dimethylstyrene or mixtur_s
thereo , of which styrene is most preferred.
Suitab:e conjugated dienes to be used in the block _~polymer
of com?onent (a) are 1,3-butadiene, 2-methyl-1,3-bu~_d-ene
(isoprene), 2,3-dimethyl-1,3-butadiene, 1,3-pentadie-.e,
1,3-he~adiene or mixtures thereof, of which 1,3-buta^ ene,
isopre~.e or mixtures thereof are the preferred monc..e-s.
Isoprene is most preferred.
; As already indicated supra, it is preferred that th_ ^:ock
copolymer is a multi-armed styrene(S)-isoprene(I) c-
styrene-butadiene(B~ block copolymer having a styren-
conten~ in the range of from S to 25~ by weight. Ar. -~ample
of a c_mmercially available multi-armed S-I block c_-o ymer
is KRA~ON D-1320X (KRATON is a trade mark).
VDS2033 ~ENOED SHEET
-~O 95/02640 ~ 1 ~ 7 1 ~ 5 PCT~EP94/02314
The photoinitiator component (b) in the block copolymer
composition according to the present invention may be composed of
one or a combination of two or more photoinitiators. In any event,
at least one of the photoinitiators used must be a compound
cont~ining a carbonyl group which is directly bonded to at least
one aromatic ring structure. It is preferred that this
photoinitiator is selected from the group consisting of:
(l) at least one benzophenone of the general formula (I)
R2 ~ R3 ~ R6 (I)
wherein Rl to R8 independently represent hydrogen or an alkyl
group having from l to 4 carbon atoms, preferably methyl, and
wherein R7 and/or R8 represent in addition alkoxy of l to 4
carbon atoms and wherein n has a value of 0, l or 2,
optionally in combination with at least one tertiary amine,
(2) at least one sulphur-containing carbonyl compound, wherein the
carbonyl group is directly bound to at least one aromatic
ring, preferably of the general formula II
R1 ~R1 ~
wherein R , R , R each may represent hydrogen, alkyl of 1-4
carbon atoms or an alkylthio group, having l to 4 carbon
atoms, and
(3) mixtures of (l) and (2).
W O 95/02640 2 ~ ~ 7 T ~ 5 PCT~EP94/02314
Examples of suitable compounds of category (1) are benzo-
phenone, 2,4,6-trimethylbenzophenone, 4-methylbenzophenone and an
eutectic mixture of 2,4,6-trimethylbenzophenone and 4-methylbenzo-
phenone (ESACURE TZT) and 2,2-dimethoxy-1,2-diphenylethan-1-one
(IRGACURE 651) (ESACURE and IRGACURE are trade marks). These
compounds may be employed in combination with tertiary amines, such
as e.g. W ECRYL 7100 ( W ECRYL is a trade mark).
Category (2) embraces compounds such as e.g. 2-methyl-1-[4-
(methylthio)phenyl]-2-morpholinopropanone-1, commercially available
as IRGACURE 907 (IRGACURE is a trade mark).
An example of suitable mixtures (category (3)) is a mixture of
15% by weight of a mixture of 2-isopropylthioxanthone and
4-isopropylthioxanthone, and 85% by weight of a mixture of 2,4,6-
trimethylbenzophenone and 4-methylbenzophenone. This mixture is
commercially available under the trade name ESACURE X15.
Photoinitiators of any one of the above categories (1), (2)
and (3) may also be used in combination with other photoinitiators,
such as e.g. W ECRYL P115. Particularly useful is a combination of
benzophenone and said W ECRYL P115.
In a preferred embodiment of the present invention the
photoinitiator is selected from the group consisting of (i)
benzophenone, (ii) a mixture of benzophenone and a tertiary amine
containing a carbonyl group which is directly bonded to at least
one aromatic ring, and (iii) 2-methyl-1-[4-(methylthio)phenyl]-2-
morpholinopropanone-l. Of these 2-methyl-1-[4-(methylthio)phenyl]-
2-morpholinopropanone-1 is most preferred.
The photoinitiator should be present in an amount of from 0.5
to 30 parts by weight per 100 parts by weight of block copolymer
(phr) to ensure sufficient cross-linking upon exposure to W
irradiation. It is preferred that the photoinitiator is present in
an amount of from 5 to 20 phr.
The W irradiation used for cross-linking the block copolymer
composition of the present invention in principle may be any W
source having an output spectra showing one or more peaks at
wavelengths between 200 and 500 nanometer (nm). Particularly
216/185
~ WO 95/02640 PCT~EP94/02314
- 7
suitable W sources are Fusion bulb lamps (Fusion is a trade mark)
having output maxima at 260-270 nm, 320 nm and 360 nm ("H" bulb),
at 350-390 nm ("D" bulb) or at 400-430 nm ("V" bulb). Combinations
of these Fusion bulb lamps may also be used. H and D bulb lamps
(linear power 300 W/inch) are particularly useful, while a
combination of D bulb and H bulb can also be suitably applied.
The exposure to W irradiation may be performed by any known
method. A suitable method for instance is exposing a sample either
in a layer obtained from a hot melt or in a layer obtained by
solvent coating to W irradiation by passing said sample at a
certain speed (expressed in meters per minute, m/min) underneath
the W source. If necessary, the exposure to irradiation may be
repeated one or more times, e.g. by repeatedly passing the sample
underneath the W source or by passing the sample underneath two or
more lamps positioned in series, in order to accomplish sufficient
curing. The lower the total irradiation dose and the higher the
speed with which the sample can be passed underneath the W source
for obtaining sufficient and satisfactory curing, the better the
curing ability of the said sample.
The W curable block copolymer composition according to the
present invention can be suitably applied in hot melt as well as
solvent adhesive compositions, sealants and coatings. When used in
adhesive compositions, common additives, such as a tackifying
resin, a softening oil and an antioxidant may also be present. For
instance, a suitable hot melt adhesive composition may comprise in
addition to the block copolymer composition of the present
invention:
(c) 10-300 parts by weight per lO0 parts by weight of block
copolymer (phr) of at least one resin which is compatible with
the poly(conjugated diene) polymer block(s);
(d) 0-150 phr of a plasticizer; and
(e) 0.5-5 phr of an antioxidant.
Suitable poly(conjugated diene) compatible resins are
tackifying resins and liquid resins, such as e.g. polyterpene
resins, polyindene resins, rosin esters, hydrogenated rosins,
wo gs/02640 2 1 6 7 1 a 5~ PCT~EP94/02314
alpha-pinene resins, beta-pinene resins, hydrocarbon resins of
petroleum origin and phenolic resins. Examples are REGALITE R91,
R101, R 125 and S260 (REGALITE is a trade mark), ESCOREZ 1310 and
5380 (ESCOREZ is a trade mark), WINGTACK 95 (UINGTACK is a trade
mark), FORAL 85 and 105 (FORAL is a trade mark), PICCOLYTE A115,
S115 and S10 (PICCOLYTE is a trade mark) and PICCOTAC 95E. The use
of resins having a low degree of unsaturation, such as REGALITE
R91, R101 or R 125, is preferred.
As a plasticizer mineral oils, both naphthenic and paraffinic
oils, or low molecular weight polybutylene polymers may be used.
Examples of suitable plasticizers are SHELLFLEX 371 and 451 and
TUFFLO 6204 (naphthenic oils), TUFFLO 6056 (paraffinic oil) and the
polybutylenes HYVIS 200, NAPVIS 30 and NAPVIS D-10. SHELLFLEX,
TUFFLO, HYVIS and NAPVIS are trade marks. Also very useful are
REGALREZ 1018 (REGALREZ is a trademark), ONDINA 68 (ONDINA is a
trade mark) and V-OIL 7047 (V-OIL is a trade mark).
As component (e) any antioxidant commonly applied in adhesive
formulations may be used. An example of such antioxidant is the
phenolic compound IRGANOX 1010 (IRGANOX is a trade mark).
In addition to the components (c), (d) and (e) other
additives, such as endblock compatible resins, W stabilizers,
fillers, flame retarders and the like, may be present as well
depending on the specific conditions under which the hot melt
adhesive composition is to be used.
Hot melt adhesive compositions, sealant compositions and
coating compositions comprising the W -curable block copolymer
composition described hereinbefore also form part of the present
invention. The same applies for cured compositions obtained by
exposing said adhesive, sealant and coating compositions to W
irradiation-
The invention is further illustrated by the following
examples, however without restricting the scope of the invention to
these specific embodiments.
The photoinitiators used in the examples have been abbreviated
as follows:
-~0 95/02640 2 1 6 ~ 1 8 5 PCTAEP94/02314
TZT : ESACURE TZT I184 : IRGACURE 184
X15 : ESACURE X15 I651 : IRGACURE 651
P115 : W ECRYL P115 I907 : IRGACURE 907
W EC : W ECRYL 7100 Benz : Benzophenone
Unless otherwise mentioned, the samples were irradiated by a
W source while being exposed to a soft flow of nitrogen. This flow
of nitrogen was such that oxygen was still present during
irradiation. Accordingly, irradiation took place in the presence of
up to 10 volume % of oxygen.
Example 1
A formulation consisting of a multi-armed S-I block copolymer,
two polyisoprene compatible resins and an antioxidant was prepared
by intimately mixing:
100 pbw of KRATON D-1320X,
150 phr REGALITE R91,
60 phr REGALREZ 1018, and
1 phr IRGANOX 1010.
KRATON D-1320X is a multi-armed block copolymer consisting of S-I
block copolymer arms. The coupling agent used is divinylbenzene. It
has a polystyrene content of 10% by weight. The apparent molecular
weight of each S-I arm is about 100,000 and the peak molecular
weight of each polystyrene block is about 11,000. The total number
of arms may vary from 6 to 100 and usually is between 6 and 40.
To this formulation several photoinitiators were added after
which the compositions thus obtained were exposed to W irradiation
by passing the formulation as a hot melt underneath a single Fusion
D bulb lamp (F300; 300 W/inch) at a speed of 5 m/min. Of these
compositions the Shear Adhesion Failure Temperature (SAFT) was
measured. A value of 140 C or higher is acceptable. The results
are listed in Table I.
W O 95/02640 2 1 6 ~ t ~ 5~ PCT~EPg4/02314 _
- 10 -
TABLE I W curing of several formulations
photoinitiator (pbw)
TZT X15 I651 I184 W EC SAFT (C)
1 pass 2 passes
110 >160
>160 >160
114 >160
>160 >160
3 2 10 >160 >160
151 >160
3 3 137 140
>160 >160
>160 >160
From table I it is clear that all formulations show excellent SAFT
values after 2 passes underneath the D bulb W lamp, (300 W/inch)
while five formulations already give excellent SAFT values, i.e.
>160 C, after only 1 pass.
Examp;e 2
The same base formulation as used in Example 1 was employed
for the evaluation of the effect on the SAFT values of the speed
with which a formulation is passed underneath various W sources.
The photoinitiator used was IRGACURE 907 in an amount of 5 pbw per
100 pbw of block copolymer. When two bulb lamps were positioned in
series (indicated as D+V, D+H and D+D), the exposure to the
irradiation originating from the second lamp took place in air, so
without applying a nitrogen flow. The results are listed in table
II; the SAFT values listed are given in C.
~qo gs/02640 2 1 6 7 1 8 5 PCT~EP94/02314
TABLE II SAFT values after W curing at different speeds and with
different W lamps
Speed D bulb D+H bulb D+V bulb D+D bulb
(m/min) l pass 2 passes 1 pass 1 pass 1 pass
>160 >160 >160 >160 >160
112 >160 >160 >160 123
104 131 >160 118 105
97 106 156 104 98
The H and V bulb had a linear power of 300 W/inch (120 W/cm)
From table II it is clear that particularly the combination of a D
bulb lamp followed by a H bulb lamp gives excellent results, even
at such high speed as 20 m/min.
Characteristic adhesive properties (loop tack and peel
adhesion) were also measured of same irradiated samples as listed
in Tables III and IV.
TABLE III
Looptack: Influence of the lamp and speed (N/25mm)
Speed D-Bulb (l lamp) D+H Bulb D+D Bulb
M./Min. 1 pass 2 passes 1 pass l pass
with without with without with with without
*
26 28 26 25 23 21 21
27 - 25 - 21 26
26 24 24* 26 22
- 22 - 23 24
'with': means with low N2 flow - 'without': means that the samples
were cured in open atmosphere (no N2 flow).
*: zippery tack
W O 95/02640 2 1 6 7 1 ~ 5 PCT~EP94/02314
TABLE IV
Peel adhesion: Influence of the lamp and speed (N/25mm)
Speed D-Bulb (1 lamp) D+H Bulb D+D Bulb
M./Min. 1 pass 2 passes 1 pass 1 pass
with without with withoutwith with without
19 19 16 17 17 19 19
20 - 18 - 17 19
17 19 19 18 16 17
16 - 20 - 21 19
From these tables it will be appreciated that the adhesive
properties are not damaged by the curing.
Example 3
The same formulation as used in Example 2 was employed and
exposed to irradiation using a Fusion H bulb lamp (F300) with and
without a nitrogen flow. The formulation was exposed to irradiation
by passing it at different speeds once and twice underneath the H
bulb as well as by passing it once underneath two H bulb lamps
positioned in series. The SAFT values (in C) were measured after
each pass. The results are listed in table V.
2167185
~0 95/02640 PCT~EP94/02314
- 13 -
TABLE V SAFT values after W curing with and without nitrogen
flow
Speed 1 lamp 2 lamps
(m/min) l pass 2 passes 1 pass
withwithout withwithout without
173 166 174 169 172
146 159 160 159 155
106 108 137 152 167
88 85 107 lO1 117
From table V it can be derived that irradiation in air, so without
applying a nitrogen flow, results in excellent SAFT values which
are similar to, and in some cases even better than, the SAFT values
obtained by applying a nitrogen flow during exposure to
irradiation.
Example 4
Several photoinitiators and combinations of photoinitiators
were added to the base formulation as used in Example 1. The
compositions thus obtained (compositions A to G) were cured by
passing them three times (lp, 2p, 3p) at a speed of 5 m/min
underneath a Fusion D bulb lamp. The SAFT values, of some
compositions the Holding Power at 95 C (HP 95C) and the peel
adhesion 180 were determined after each pass. The results are
listed in table VI.
W O 95/02640 2 ~ 5,!1 PCT~EP94/02314 _
TABLE VI
W curing of block copolymer compositions
Composition A B C D E F G
Benz 5 5 10 10 5 10
I651 5 5
W EC 10
P115 10
I907 5
lp 150 148 157133 155~160 141
SAFT (C) 2p >160 >160 158>160 >160>160 147
3p >160 >160 159>160 >160>160 151
lp >100 >100 >100>100 >100
HP 95C 2p>100 >100 >100>100 >100
3p>100 >100 >100>100 >100
Peel- lp 20 18 16 19 16 16 10
adh. 180 2p 18 20 21 21 16 15 12
(N/25mm) 3p 21 20 18 22 17 16 13
From table VI it 'can be seen that in particular the W cured
adhesive compositions A to F exhibit excellent adhesive properties.
Example 5
A formulation, comprising: KRATON D-1320 X 100 phr
REGALITE R 91 150 phr
RF.GATRF.7. 1018 60 phr
IRGACURE 907 5 phr
IRGANOX 1010 1 phr
was tested with irradiation from another W -lamp, the H-bulb, which
substantially emits the conventional mercury spectrum.
The SAFT test results obtained have been listed in Table VII:
- ~0 95/02640 2 1 6 7 1 8 5 PCT~EP94/02314
- 15 -
Table VII
~ SAFT: Influence of the H-bulb lamp (C)
- Speed 1 Lamp 2 Lamps
M./Min. 1 pass 2 passes 1 pass
with without with without without
5 171 167 171 169 168
10 145 148 164 155 147
>160 >160
99 107 137 152 >160
88 85 107 101 112
From this table VII it will be appreciated that the N2 is not
necessary and has hardly any influence on the curing efficiency of
this formulation. Moreover it appeared possible to have a good
curing efficiency with two passes under the H-lamp up to 15 m/min
(SAFT higher than 150 CC).
The adhesive properties of these samples have also been
measured and listed in Tables VIII and IX.
wo 95/02640 2 1- ~ 7 ~ ~5 PCT~EW4/02314
- 16 -
Table VIII
LOOPTACK: Influence of the H-bulb lamp (N/25mm)
Speed 1 Lamp 2 Lamps
M./Min. 1 pass 2 passes 1 pass
with without with without without
23 15 18 21
24 25 24 24 21
24 23 23 25 23
23 20 20 20 21
* - zippery tack
TABLE IX
Peel adhesion: Influence of the H-bulb lamp (N/25mm)
Speed 1 Lamp 2 Lamps
M./Min. 1 pass 2 passes 1 pass
with without with without without
17 18 16
18 18 17 18 16
19 20 16 16 19
19 21 20 22 19
From the previous results it will be appreciated that the
adhesive properties are not damaged by the curing whatever the
curing speed or dose.
Example 6
A similar formulation (KRATON D-1320X/REGALITE
R91/REGALREZ 1018/IRGANOX 1010;100/150/60/1) was used with a
- ~O 95/02640 2 1 6 7 1 8 ~ PCT~EP94/02314
combination of benzophenon and EBECRYL 7100 (or W ECRYL 7100: both
trade names exist for the same product) as photoinitiator. The
- samples were irradiated under a H-bulb at different speeds. The
temperature resistance results (SAFT and Holding Power 95 C) have
been listed in Tables X and XI:
TABLE X
SAFT: Influence of curing speed (C)
Adjusted
components
benz. EBECRYL 5 m./min. 10 m./min. 15 m./min. 20 m./min.
1 p 2 p 1 p 2 p 1 p 2 p1 p 2 p
10 10 156 163 154 158 92 159111 130
5 10 155 169 159 - 97 10595 108
* = zippery tack
TABLE XI
HP 95 C: Influence of curing speed (h)
Adjusted
components
benz. EBECRYL5 m./min10 m./min15 m./min 20 m./min
500 g 1 kg500 g 1 kg500 g 1 kg500 g 1 kg
10 10 1 p > 100 6 0.07
~ 2 p > 100 61 > 100 77 15
W O 95/02640 2 1 6 7 1 85 PCT~EP94/02314
- 18 -
From these data it will be clear that also good curing efficiency
was obtained in open air with a combination of benzophenon and
tertiary amine as photoiniator.
Example 7
1. Two radiation curable block copolymer mixtures (A and B) of
molecular structure (SB) B X, wherein m + n - 4, and each of m and
n had an average value of about 2, wherein X represented the
residue of tetrachlorosilane, were tested in an "open air"
irradiation process with two photoinitiators covered by the present
application, i.e. IRGACURE 651 and IRGACURE 907 respectively.
Further details of these polymers have been listed in
Table XII.
TABLE XII
Polymer A B
% PS 12.7 10.8
% vinyl 54 56
CE 96 95
T -59 C -56 C
MFR 8.1 1.4
Adhesive Composition (3) (4) (5) (6)
polymer 100 phr 100
REGALITE 91 147 129
~F.~AT.F.7. 1018 63 81
IRGACURE 651 3 3
IRGACURE 907 3 3
IRGANOX 1010 2 2
2i6718~
~ ~0 95/02640 PCTAEW4/02314
- 19 -
The samples were cured at different speeds, under a F-300
D-bulb lamp. These adhesive formulations were irradiated in direct
- cure, with low N2 flow. The results have been listed in Table XIII.
WO 95/02640 2 1 6 7 ~ &5 PCT/EP94/02314
-- 20 --
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21671~5
-~0 95/02640 PCT~EP94/02314
2. The experimental polymers A and B of the formula (SB) B X were
then cured with a more powerful lamp at higher speeds, without any
nitrogen flow.
The photoinitiators IRGACURE 651 and 907 were both tested in
compositions, containing the same other ingredients as specified in
Table XII, i.e. formulation 4 is based on A ~olymer with
IRGACURE 651, formulation 5 is based on B polymer with IRGACURE
651, formulation 6 is based on B with IRGACURE 907.
All the samples were irradiated in direct curing by means of
Fusion F-600 lamps.
The results have been listed in Tables XIV and XV.
TABLE XIV
Speed D-bulb I H-bulb
m./min 4 5 6 1 4 5 6
I
0 75 80 175 80
>170 >170 >170 1>170 >170 >170
77 >170 >170 1170 >170 >170
153 >170 1166 >170 >170
105 >170 195 >170 >170
74 86 141 186 118 >170
76 8~ 95 177 92 127
I
SAFT results (C) for samples cured under one F-600 lamp
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TABLE XV
Speed D + D bulb I D + H bulb
m./min 4 5 14 5 6
O 75 80 175 80
>170 >170 1>170 >170 >170
>170 >170 1150 >170 >170
111 >170 1106 147 >170
82 114 186 >170 >170
110 184 >170 >170
SAFT results (C) for samples cured under a combination of
F-600 lamps
It will be appreciated that improved results were obtained,
when using the IRGACURE 907 photoinitiators. The best results were
obtained for a B polymer based formulation irradiated by a
combination of D and H bulbs. In this case, SAFT results higher
than 170 C could be obtained at a speed of 60 m./min! This is the
highest speed which ever could be reached in radiation curing.
Holding Power (HP) at 95 C:l kg.
Only the samples which had good temperature resistance
properties were selected to perform a HP 95 C test, as listed in
Table XVI.
21671~5
-~VO 95/02640 PCT~EW4/02314
- 23 -
TABLE XVI
Speed D-bulb I H-bulb
m./min 4 (h) 5 (h) 6 (h) I 4 (h) 5 (h) 6 (h)
I
10 >100 >100 >100 1 >100>100 >100
>lO0 >lO0 1 0.5/12.5 >lO0 >lO0
>lO0 1 0/429.5/>lO0 >lO0
- - >lO0 1 0 >lO0 >lO0
- - - I - - 8.6
HP 95 C results of samples cured under one F-600 lamp
TABLE XVII
Speed D + D bulbs I D + H bulbs
m./min4 (h)5 (h) I 4 (h) 5 (h) 6 (h)
I
>lO0 >lO0 1>lO0 >lO0 >lO0
>lO0 >lO0 1l9/>lO0 >lO0 >lO0
- >lO0 1 - >lO0 >lO0
- - I - >100 >100
- - I - >lO0 >lO0
HP 95 C results of samples cured under a combination of F-600
lamps
Here again we can see the good temperature performance
(HP95 C > lO0 h) of the experimental polymers when using
IRGACURE 907 photoinitiator. IRGACURE 907 enabled the achievement
of higher curing speeds.
W O 95/02640 2 1 6 7 1 8 5 PCT~EP94/02314
From the preceding examples it will be appreciated that it
became possible to effectively cure in presence of oxygen without
the need of a N2 flow. High curing efficiency and temperature
resistance properties achievable at high speed could be reached.
Example 8
(i) Five standard radiation sensitive compositions were prepared,
comprising 100 parts by weight of each of the block copolymers
contA i n i ng po ly ( s tyrene) and poly(butadiene) blocks, listed in
Table XVIII, 1 part by weight of the antioxidant IRGANOX lOlO and 2
parts by weight of photosensitizer IRGACURE 651.
The last block copolymer listed in the table is not according
to the claimed invention and has been included as comparative
example.
TABLE XVIII Polymer characteristics
Block Mol.wt. Mol.wt. Total mol.wt. Molecular Poly- Vinyl-
Copolymer (xlOO0) (x1000) (x1000) form styrene (1,2-add)
of S of S-B content content
block block
A 10.7 71 276 (SB)2B2 12.7 54
B 11.2 87 339 (SB)2B2 10.8 56
C 10.7 81 222 (SB)2B2 12.5 60.5
KRATON D 13 330 (SB)3 5 21 +/- 5
1116
Comp. 12 45 91 SBS 40 +/- 5
From the five photosensitive compositions films of 22 micron
thickness were prepared from a solvent based formulation (40% in
toluene) by casting.
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- 25 -
The films were irradiated under a Fusion D bulb lamp in 1 pass
and 2 passes respectively with a speed of 5 m/min, and the gel
content was analyzed.
The gel contents have been listed in Table XIX.
TABLE XIX Gel percentage after irradiation
Polymer 1 pass 2 passes
A 59.5 85.5
B 81.0 86.9
C 73.8 87.5
KRATON D 1116 31.7 70.4
Comp. 0.3 9.6
(ii) Photosensitive compositions were prepared from the block
copolymer identified hereinbefore as A (lOO parts by weight),
IRGANOX lO10 (1 part by weight) and varying amounts of
photosensitizer IRGACURE 651, as listed in the Table XX.
Films of 22 micron thickness were prepared from these
compositions and the films were irradiated as described under
Example 8(i). The percentage.gel after irradiation was determined.
TABLE XX % gel after irradiation
Composition
block Copol./AO/PS 1 pass 2 passes
100/1/1 46.2 73.3
100/1/2 59.5 85.5
100/1/4 84.7 93.7
