Note: Descriptions are shown in the official language in which they were submitted.
~^~
~L~398~
This invention relates to copolymers of acrylonitrile
and vinylidene chloride and to their produc-tion. The co-
polymers according to the invention are capable of producing
shaped articles with a high degree of non-inflammability
through the additional incorporation of an unsaturated
phosphonic acid ester. More particularly, the invention
relates to substantially non-inflammable textile filaments
which, after knitting up, withstand the vertical burning
test defined in DIN 53 906.
It is known that the inflammability and burnability
of polyacrylonitrile can be reduced by copolymerising
halogen-containing compounds, for example vinylidene chloride,
in proportions of up to 45 % by weight. The requirement
for a further increase in non-inflammability, which provides
for safe passing of the vertical burning test defined in
.. :.
DIN 53 906, has been acquiring more and more significance ~ `
over recent years. ~ -
It is known that the combinatlon of halogen- ~ `
"~ containing substances with phosphorus compounds can have a i~
synergistic effect upon the non-inflammability of polymers.
Thus~ German Offenlegungsschrift No. 2,154,676 relates to ;
modacrylic fibres of acrylonitrile and vinylidene chloride
which contain bis-(2-chloroethyl)-vinyl phosphonate as
phosphorus-containing comonomer and which are capable of
withstanding a 45 degree burning test. One serious dis-
,t,, .'., ~ ~ advantage of the production of these fibres is that co-
r polymerisation has to be carried out in the presence of
emulsifiers on account of the insolubility in water of the
aforementioned phosphonic acid ester. In a process carried
~- 30 out on a commercial scale, the polymer is difficult to work~
:c
..:
. - 1 -
.'. ,
- 1~398~
up because the emulsion has to be precipitated. Recovery
of the unreacted monomers is difficult and the polymers
obtained lack heat stability, in other words they show a
tendency towards yellowing during spinning.
It has now been found that phosphonic acid esters
corresponding to the general formula
:- , .
~, OR2 :
CH2 = C- ( CH2 )n~P \
Rl 3
in which
R1 represents hydrogen or a methyl, acetoxy, chlorine ;~ ;
or phenyl radical,
R2 and R3 represent a methyl, ethyl, n-propyl, i-propyl,
n-butyl, i_butyl radical, and `
: n = 0 or 1, in addition to which
R2 and R3 may also represent methylene eroups which are i~
attached through another carbon atom to a 1,3-dioxa-2-
phosphorinane ring system alkyl- and/or halogen methyl~
substituted in the 5-position, -
can be copolymerised with acrylonitrile and vinylidene
chloride by suspension polymerisation in an aqueous medium
in the absence of emulsifiers, thus avoiding the disadvantages
.. : ,. . ~ .
of emulsion polymerisation. ~;
Accordingly, it is an object of this invention to
provide a flameproof acrylonitrile copolymer. It is a further
object to provide a process for the production of such copoly- ;
mers. More specifically it is an ob~ect of this invention
to avoid the disadvantages in processing as disclosed above -
and to avoid the disadvantages in view of the properties
of the known copolymers.
.
.,.'` ~'.
- 2 -
:'~
,.
.. ..
~ 1~39894
.
.~ Other obJect will be evident ~rom the description and
the Examples.
These ob~ects are accomplished by a flameproof copolymer
of acrylonitrile, vinylidene chloride, a comonomer containing
acid groups and at least one unsaturated phosphonic acid ester
~"' .
corresponding to the general ~ormula
OR
R OR3
- in which
, Rl represents hydrogen or a methyl, acetoxy,
chlorine or phenyl radical, - -
.- ~
R2 and R3 represent a methyl, ethyl, n-propyl, i-propyl,
n-butyl, i_butyl radical, and
n = O or 1, in addition to which
--- R2 and R3 may also represent methylene groups
which are attached through another carbon atom
,,J,~, to a 1,3-dioxa-2-phosphorinane ring system aIkyl-
and/or halogen methyl-substituted in the 5-
position, in copolymerized form.
More particularly, the invention relates to flame- -
proof copolymers which are characterised by the fact that
~: they contain from 35 to 73 % by weight of acrylonitrile,
i -, :
from 25 to 40 % by weight of vinylidene chloride, Yrom 1.5
~::, to 15 % by weight of at least one unsaturated phosphonic
:.;
acid ester corresponding to the general formula in Claim 1,
rom 0.5 to 3.0 % by weight of a copolymerised monomer
containing acid groups and, optionally, up to 7 % by weight
, of another comonomer from the group comprising (meth~ acryl-
amide, vinylacetate and methylacrylate.
. . ,~ .:
: .
,.,., ,; . ~ . ~ . ' , . , ., : '
39~
The invention also provides a process for the
production of flameproo~ copolymers by polymerising
acrylonitrile, vinylidene chloride 9 at least one unsatur~ted
phosphonic acid ester, a monomer containing acid groups and,
optionally, another comonomer, optionally in the presence
of a heavy metal salt, in aqueous medium at a pH value of
from 2 to 5 and at a temperature in the range from 25 to
50 C. with a redox catalyst system of alkali per sulphate
and alkali bisulphite in a quantity of from 0.5 to 10 %
by weight, based on the total monomer mixture, in the ratio -.
of oxidising agent to reducing agent being from 1 : 1 to ;
1 : 10, characterised by the fact that from 35 to 73 % by
weight of acrylonitrile, from 25 to 40 % by weight of ~ .
vinylidene chloride, from 1.5 to 15 % by weight of at least
one unsaturated phosphonic acid ester corresponding to the .
general formula
i ~
~ / OR
: CH C (CH ) P
R
in which Rl, R2, R3 and n are as previously defined~
~ from 0.5 to 3 % by weight of a copolymerisable monomer
. 20 containing acid groups and, optionally, up to 7 % by weight
of another comonomer from the group comprising (meth) acryl- ~ :
amide, vinylacetate and methylacrylate, are polymerised
optionally in the presence of from 0.1 to 25 ppm of a heavy
:: metal salt, preferably iron (II) sulphate heptahydrate, all
the quantities specified being based on the monomer mixture .
~ as a whole.
`.............................. Comonomers containing acid groups suitable for use in
~ accordance with the invention are compounds which, in addit-
:: ,
ion to an ethylenically unsaturated double bond, contain an
acid group, preferably a sulphonic acid group, for example
- 4 -
1~398~
methacryloyl amino benzene benzene disulphimide, tmeth) ;
allyl sulphonic acid, vinyl sulphonic acid, styrene sulphonic
acid and their salts. It is preferred to use sodium meth-
allyl sulphonate.
The invention is particularly concerned with the use -
of the aforementioned flameproof copolymers for the produc-
tion of fibres, filaments and sheeting.
In order to obtain an effective phosphorus content in
the copolymers according to the invention in the most
economic manner possible, the phosphonic acid esters used
must be highly pure and sufficiently resistant to hydrolysis
under the polymerisation conditions.
It has now been found that, for substantially the
same degree of purity (95 to 98 % according to analysis by
gas chromatography), incorporation of the phosphonic acid
ester into the acrylonitrile/vinylidene chloride system `~
increases from 50 to 80 to 90 % by weight in the order -~
methyl-, ethyl-, propyl ester. In addition, substantially /;
. .
quantitative incorporation is obtained with substitution on
the ~-carbon atom of the vinyl group or on the ~-carbon atom
of the allyl group by such substituents as halogen, alkyl,
acetoxy, phenyl radicals. These results are set out in
the following Table 1.
~his increase in the incorporation of the phosphonic
acid ester when ~- or ~-hydrogen atoms of the acid and/or
alcohol function are replaced by more bulky groups than the
hydrogen atom, is obviously attributable to a reduction in
the tendency towards hydrolysis of the corresponding ester
and hence in its tendency to form free phosphonic acid groups -
under the polymerisation conditions, with the result that
copolymerisation of the phosphonic acid ester is no longer
adversely affected by desactivation of the iron ions required
- 5 -
~39~394
for redox activation in the polymerisation mixture. For
example, the incorporation of vinyl phosphonic acid diethyl
ester can be increased from 49 to 60 % by the addition of
small quantities of iron (II) sulphate (Table 2).
The proportion of 1.5 to 15 ~ by weight of copolymer-
ised phosphonic acid dialkyl ester in the claimed range
reduces inflammability and burnability by comparison with
modacrylonitrile fibres not containing copolymerised
phosphonic acid dialkyl ester but with the same vinylidene -~ ~
chloride content. If the copolymerised phosphonic acid ~ ~ ?
ester content is beyond the claimed range, the result is a
loss of strength and an increase in boiling-induced and `~
heat-induced shrinkage, i.e. a reduction in the dimensional
stability of filaments obtained from copolymers of this kind.
With a phosphonic acid ester content of less than 1.5 % by
weight, there is no further improvement in the flameproof
properties. ~y copolymerising acrylonitrile and vinylidene
chloride with the phosphonic acid esters according to the
invention in the claimed range, it is possible to produce
filaments with improved non-inflammability having textile
properties, such as strength and shrinkage, comparable with
those of unmodified modacrylonitriles.
The increased non-infla~mability of the filaments
according to the invention was tested by the vertical burning
test according -to DI~ 53 906 after they had been knitted up
both into articles of filament yarn and into articles of
fibre yarn. All the phosphorus-modified copolymers with- -
stand the vertical burning test and are self-extinguishing.
This is a significant advantage over conventional copolymer
compositions with the same vinylidene chloride content.
- 6 -
~39E~9~ ~
The non-inflammable copolymers according to the
invention are distinguished by high thermal stability in
dimethyl formamide. In order to test their thermal
stability, the new copolymers were tempered in dimethyl
formamide along with corresponding comparison polymers, and
the concentration of chlorine ions in the solutions determin-
ed by potentiometric titration (Table 3).
The polymers according to the invention show a higher
affinity for basic dYes than comparable, unmodified polymer
compositions. This increased affinity for basic dyes of
the new polymers is reflected in the fact that films
produced from them can be strongly dyed with basic dyes
(Table 4).
The advantage of ~he new copolymers is that, through
the additional incorporation of suitable, unsaturated
phosphonic acid esters, preferably hydrolysis-resistant
higher phosphonic acid esters from the group comprising (un) ~`
substituted vinyl and allyl phosphonic acid esters, into the
acrylonitrile/vinylidene chloride system on the principle of `~
suspension polymerisation in aqueous medium, it is possible
to obtain products which, by virtue of synergistic effect
on the part of phosphorus and chlorine, provide the filaments
spun from them after knitting-up in the manner described
above with such a high degree of non-inflammability and non- .
burnability that the kni-tted articles withstand the vertical
burning test (DIN 53 906) by going out following removal of
the ignition flame (Table 5).
Another advantage of the polymers according to the
invention is that, by virtue of the synergistic effect of
phosphorus and chlorine, it is possible to reduce the
vinylidene chloride content of the copolymer, so that, with
the appropriate composition, thermostable filaments spun
- 7 -
1~39~394 ;:
from the new products have textile properties, for example
strength and shrinkage behaviour, which are comparable with
those of unmodified modacrylonitriles.
The copolymers according to the invention can be pro-
duced in known manner by polymerising the monomers either
in batches or continuously in aqueous medium at pH-values
in the range from 2 to 5, preferably in the range from 2.5
to 3.5., and at temperatures in the range from 25 to 50 C,
preferably at temperatures in the range from 30 to 40 C.
A heavy metal salt, preferably iron (II) sulphate, may
. . .
optionally be added to the polymerisation mixture in a
quantity of from 0.1 to 25 ppm, based on the monomer mixture
as a whole, in order to increase incorporation of the
aforementioned phosphonic acid ester into the acrylonitrile/
vinylidene chloride system. An alkali persulphate/alkali
bisulphite system is preferably used as the redox catalyst
system. The catalysts are used in quantities of from 0.5
to 10 % by weight, based on the monomer mixture as a whole.
The ratio of oxidising to reducing agent is in the range
from 1 : 1 to 1 : 10, preferably in the range from 1 : 2 to ~ -~
1 : 8. The ratio of total monomer to water can be in the
range from 1 : 5 to 1 : 15 and is preferably in the range
from 1 : 5 to 1 : 10.
: Solutions prepared from the new polymers, for example
,, . ~ .
in dimethyl formamide, are clear, colourless, gel-free and
can be spun both by wet-spinning and by dry-spinning techniques.
The following Examples are to further illustrate
the invention without limiting it.
': : - . . . :, : - - -. ~ ,
EXAMPLE I 1~39~94
222 g of vinylidene chloride, 330 g of acryloni-trile,
30 g of ~inyl phosphonic acid diethyl ester and 72 g of
25 % by weight aqueous methacryloyl amino benzene benzene
disulphimide solution were introduced together with 2 ml of
a 0.1 % aqueous iron (II) sulphate heptahydrate solution into
a 10 litre capacity three-necked flask filled with 5.9 litres
of oxygen-free water and rinsed with nitrogen, followed by
adjustment to pH 2.8 with dilute sulphuric acid. After `~
10 heating to 32 C and adding 9 g of potassium peroxy disulphate,
polymerisation was started by running in a solution of 18 g
of sodium bisulphite in 100 ml of water. The pH-value of
the reaction mixture was monitored during the reaction and
adjusted if necessary. The polymer suspension was filtered
off after a reaction time of 6 hours, washed free from salts
with water and dried at 50 C in a vacuum drying cabinet.
Yield: 504 g = 84 % of the theoretical yield
Cl [~ P ~7
Analysis: Calculated 27.1 0.95
Found 25.1 0.54
K-value (according to Fikentscher, Cellilosechemie 13,
page 58 (1932)): 82.0
EXAMPLE II
As in Example I, 192 g of vinylidene chloride, 365 g
of acrylonitrile, 30 g of vinyl phosphonic acid diethyl
ester and 13.2 g of sodium methallyl sulphonate were polymer-
ised in 7 hours in the presence of 2 ml of a 0.1 % aqueous
iron (II) sulphate heptahydrate solution. ~-
Yield: 490 g = 87.7 % of the theoretical yield ~`
Cl ~o~ P
Analysis: Calculated 23.5 0.95
Found 23.5 0.42
_ g _
,, -., .- :, . . . :
` \
:
K-value: 73.5 ~3~ :
EXAMPLE III
168 g of vinylidene chlo:ride, 354 g of acrylonitrile,
30 g of vinyl phosphonic acid diethyl ester and 72 g o~
25 % by weight aqueous methacryloyl amino benzene benzene
disulphimide solution were polymer:ised together with 2 ml of
a 0.1 % aqueous iron (II) sulphate heptahydrate solution
(monomer : water ratio 1 : 8). At the same time, a solution
of 30 g of acrylamide in 100 ml of water was added dropwise
over a period of 1 hour at the beginning of polymerisation, ;
polymerisation being continued for 5 hours after the acryl~
amide had been added. ~; .
Yield: 510 g = 85 % of the theoretical yield
Cl ~%~ P L~ acrylamide /%/ ~-
Analysis: Calculated 20. 5 0.95 5
Found 19.2 0.40 4.8
K-value: 82.4
EXAMPLE IV ~:
. ,:
As in E~ample I, 180 g of vinylidene chloride, 366 g
of acrylonitrile, 36 g of allyl phosphonic acid diethyl . :~
ester and 72 g of a 25 % by weight aqueous methacryloyl
amino benzene benzene disulphimide solution were polymerised
in 5 hours in the presence of 2 ml of a 0.1 % aqueous iron
(II) sulphate heptahydrate solution. ~ .
Yield: 528 g = 88 % of the theoretical yield ~
Cl ~ P [/1 :
Analysis: Calculated 22.0 1.04 ` ,
Found 22.2 o.66 ~ ~;
K-value: 81.4
EXAMPLE V
222 g of vinylidene chloride, 323. 4 g of acrylonitrile,
45 g of vinyl phosphonic acid dipropyl ester and 9.6 g of
-- 10 --
. . - -, . , :
.. :: . : . ' .
391~9~
sodium methallyl sulphonate were polymerised in 7 hours
- (monomer : water ratio 1 : 10).
Yield: 450 g = 75 % of the theoretical yield
C1 L~ P
Analysis: Calculated 27.1 1.21
Found 27.9 o.86
K-value: 71.5
EXAMPLE VI
192 g of vinylidene chloride, 353.4 g of acrylonitrile,
45 g of methallyl phosphonic acid diethyl ester and 9.6 g o~
sodium methallyl sulphonate were polymerised in 7 hours
(monomer : water ratio 1 : 10).
Yield: 450 g = 75 % of the theoretical yield
C1 ~] P [~
Analysis: Calculated 23.4 1.21 ~-
Found 22.7 1.20
K-v~lue: 81.9 ;` ~ ~ `
EXAMPLE VII (Comparison Example)
168 g of vinylidene chloride, 414 g of acrylonitrile
and 72 g of a 25 % by weight aqueous methacryloyl amino .
benzene benzene disulphimide solution were polymerised over
a period of 5 hours in the presence of 4.8 g of potassium
peroxy disulphate and 43.2 g of sodium bisulphite (monomer
water ratio 1 : 10).
Yield: 505 g = 84.2 % of the theoretical yield
Cl
Analysis: Calculated 20.5
Found 21.9
K-value: 81. 6
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~39~394
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Table .? 1039894
Increa6ing the i~corpor~tio~ o~ vinyl phosphonlc acld
diethyl ester into the acrylonitrile/vinylidene chloride
system
Addition o~ FeS04.7H20 in ppm no addition 1.6~ 3.35 16~8
____ ~ .............. ., . , - ~-~ .
incorporation in ~ 49 5o 57 60
. ~ __ -r- -, .; ~_ ,
20 % solutions in dimethYl formamide o~ the cPpolymer
accordin~ to the invention and o~ corr~sponding co~pariso~ :~
polymers were pnepared, tç~p~red in a dryin~ cabinet ~or 4
hours at 120C and the çonc~ntrati~n o~ chlorine ion~ in th~
solution deter~ined by potentilqmetric titratio~ wi~h ~ilver
nitrate solution.
Tablç_~
% ~f ionic chlorine ~n solution ~ ;
Polymer No. Tempering time 4 h at 120C
4 0.61
14 0.92
21 0.29
29 o.46
41 0.58
42 0.62
emulsion pol~mer o~
35.5 % of VDCl, 61~ ~q
of ACN, 3 ~ of CVP 0.97
1~ VDCl = ~inylidene chlo~ide
ACN = acrylonitrile
~VP - vinyl phosphonic acid-bi~(2-chloroethyl~ester
Approximately 50 ~m thick ~ilms were prepared ~rom
20 ~0 solutions in dimethyl~ormamide of the claimed copol~mers
and comparison p~lymer~, washed ~ree ~rom sol~ent and then
~ ~ 15-
. , .... ~ . , ... . . .. , .. . ~ ~ . .... ... . .
- ` ~
~ lO;~9B94
dyed with a red dye CI ~a~:Ls red 18 CI ~o. 11085 in ~ dye
: bath Or the following com~osition
100 ml o~ dye solution (1 g per litre)
0.1 ml of 0.5 n sodium aCetate/acetiC acid 80lution.
Dyeability wa8 determined by dlssolvlng the ~ilms
which have been boiled with water and dried, ~n dimethyl
formamide~ The extinction per g of film was dete~mined with
a photometer at a waYelength o~ 492 n m (cell length 10 ~m;
comparison solution pure dimethyl formamide; 20C).
1 0 Table~
PolyIDer No. 4 7 14 16 29 39 ~ 43
extinction/g
o~ ~ilm 32.8 1302 12t9 2~.5 32.0 1706 15~6 1102
.
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- 22 -
