Note: Descriptions are shown in the official language in which they were submitted.
Improving algae or micro-organism
anti-foulins of materials
This invention relates to a method of reducing the
susceptibility of materials to fouling by algae and
5 microorganisms by theuse of inorganic tin salts or
certain monoorgano or diorgano tin compounds.
It is known to include bio-stabilisers in certain
materials, the function of the bio-stabilisers being to
resist biological attack on the material. Such
10 biological attack may occur in different ways, for
example by mould, algae, fungi, bacteria, rodents,
fouling and slime-formation,or sea-water parasites.
The general requirements of suitable bio-stablisers may
be summarised in general as follows:
broad spectrum of anti microbial activity; no negative
influence on the material to be protected (for example
no discolouration, or deterioration in heat-stability
or light-stability); compatibility with plasticisers and
other additives (such as stabilisers, lubricants or
anti-oxidants); no negative secondary properties (such as
corrosivity, skin irritation or ~dour); thermal
resistance and low volatility und~r proc~æ~ing conditions;
storage stability; simplicity o~ application; durability in use;
and low toxicity in warm-blooded animals.
It is known to use the following practically important
substances as bio-stabilisers with biocidal effect:
10,10' oxy-bis-phenoxyarsine, N-(trihalomethylthio)-
phthalimide, diphenyl antimony-2-ethyl hexanoate, and
copper 8-hydroxy quinoline. They are generally used in
initial concentrations of form 0.3% (when used as pure
substance) to 5% (when used in solutions)~ as may be seen
~'';~ '~
..~. . ~
by reference to G~ch-ter/MUller, Plastic-additive,
Carl Hanser-Verlag, Munich 1979, page 456 and Polymer
~ngineering and Science, July 1970, Vol 10, No. 4,
page 241 to 246. Of these bio-stabilisers, copper-8-
hydroxy quinoline and N-(trihalomethyltll:lo)-pl~thalimi~e
have proved themselves particularly useful as biocides
in soft-PVC products. According to German Offenlegungsschrift
(DE-OS) 2 929 756 there may be used as anti~fouling
materials in underwater coating agents, special
dihalophenyl-~-chloro ethyl sulphone derivativ~s.
Triorgano tin compounds of the R3SnX type, where
R is an organic radical, form a further group o.f bio-
stabilisers which are known and used for their extraordinary
effectiveness against the most varied types of micro
organisms such as fungi, bacteria and algae. The
effectiveness of such compounds depends substantially
on the chain lengrth O:e the hydrocarbon radicals R
connected to the tin atom. Thus with trialkyl tin
compounds best results have bee~n achieved when
the to-tal number o~ car~)on ~torns :In the al~y~ ~rr~up~
is from 9 to 12, that is with tripropyl- and tributyl-
tin compounds. Of the aryl compounds, the triphenyl
compounds have an effect whichis comparable with the
trialkyl compounds. The triorgano tin compounds
are used for example as textile protective agents having
a biocidal effect against fungi and bacteria, or as
wood protective agents, for example in combatting
wood-destroying fungi or ship's bore worms. As anti-
fouling coatingsto prevent the underwater fouling of objects
in seas,rivers or lakes, apart from Cu20, mercury
compounds and also triorgano tin compounds, in particular
tributyl- and triphenyl tin compounds have been used;
~3--
3 6;~
in general composi.tions containing from 10 to 20%
of these active materials, based on the dried anti-fouling
coatings7 are considered necessary. In addition,
trihutyl tin compounds in particular have been used
in bi.ocide coatings to preyent attack or ~ouling by
microorgani.sms for example in damp areas. A further known
use of triorgano tin compounds such as tributyl tin oxide,
is to provide biocidal properties for plastics materials,
and in particular plasticiser-containing plastics such
as soft PVC. On the one hand the tri.organo tin compound
functions as a fungus-preventative, in particular
-~or theplasticisers, and on the other hand it functions
as a fouling preventative against mi.cro organisms
which positively attack the plastics material. However,
since tributyl tin oxide,which is preferably used, is not
light-resistant, so-called stabilised tributyl tin oxide
has to be used. In addition it is known to use tributyl
tin compounds as insecticides and as mollu~cicid~s,
disinfectant agents and ~li.m~-~ombat~ln~ ag~nt.
in the paper industry
In contrast to the lsnown use o~ triorgano tin
compounds against a wide variety ol types of biologrical
attack, hitherto inorganic tin compounds J diorgano tin
compounds o~ the R2SnX2 type and mono organo tin
compounds of the RSnX3 type have been considered to
be practically useless in this biocidal area. In this
regard reference is made to the technical specification
pamphlet of Schering AG, Industrial Chemists J "Technical
Production and Use of Organo tin compounds" by Dr. A.
Boghans and Dr. H. Plum,of March 1975.
27
Some diorgano tin compounds and some mono
organo tin compounds are known, however J for their PVC
stabilising effect; in particular they serve to prevent
decomposition reactions induced by heat,
light or oxidation in PVC, and accordingly the
compounds are used as stabilisers. However since they
do not generally have good properties with respect
to light fastness, waterproofness, lasting e~fect, heat
s-tability and workability, they are usually not used
alone, but rather in combination with other stabilisers.
~or example, dibu-tyl tin dilaur~te shows a good
light-stabilising effect but a relatively poor heat-
stability, and is thereIore usually only used in
combination with other tin stabilisers which are better
in their heat effect. Also, dibutyl tin maleate is agood
stabiliser against the adverse ef~ects of heat, but as a
,polymer compound it is insoluble in PVC and so presents
difficulties in working and has a tendency to plate-out.
In general the best heat stabilisers, which may be used
in the high-temperature working of hard PVC tv form :eOx
e~ample plates, sheets and bott~e~, ar~ ~:iorgan~h~o
tin compounds which hav~ a dl,rec-t tin-~ùlphur bond such
as dialkyl tin diiso octyl thioglycolate~s. These compounds
have the disadvantage though that they do not keep
for long in free weathering conditions, which leads to
damage of the hard PVC. The same disadvantage applies to
dioctyl tin compounds. However because of their non-
toxicity, these compounds are used for the stabilising of
PVC which is used for example in the packaging of
foodstuffs. Poor weathering resistance is also a
proper-ty of the toxically harmless mono organo tin compounds
.
~. .
~ -5-
~ ~ ~3 3 ~ ~2 7
such as polymeric monoalkyl tin oxides or-sulphides,
which again are used to stabilise PVC against the
ef-fect of heat and light in the field of foodstuff
packaging.
Thus although certain organo tin compounds are
used as stabilisers for PVC, their weather resistance is
not sufficiently high for many areas of usage. In
particular they are not generally good with regard to
long-terrn colour stability, low water absorption, and
decomposition, properties which are particularly required
of, for example, window profiles, facade profiles and
plates, roof sheeting, agricultural sheeting, swimming
pool sheeting and covers for air halls. Hence in these
and other areas o~ usage, in addition to the tin compounds
which stablise PVC against decomposition through
the effect of heat, light and oxidation, it is necessary
to incorporate other stabilisers which are eIfective
against weathering. According to the current state
o~ development in the art, barium-cadmium stabilisers
are thought to be superio~ ~o all o~h@r ~ab~ er~ and
systems in this respe~c~. Thu~ ror the purpose~ o~
weather-resistance, organo tin compounds are not used
alone as stabilisers since they show cléar damage after
a short weathering time, see for example PLAST VERARBEITER,
30th Vol, 1979, No. 112, page 747 - 751 "Barium/Cadmium
forthe stabilising of PVC,by Dr. P Bredereck and Dr. H.
Endriss".
A particularly rlifficult application of soft PVC
isin the manufacture of sheeting for use in swimming pools.
These require high weather-resistance and colour- and
light ~astness, and also resistance to biological
-6- .
attack by micro organisms and algae. It is known that
swimming pool sheets of soft PVC tend -to deposit
a slimy surface co~ting because the sur~ace roughness
of the sheet acts as an adhesive base for micro
organisms. This effect is made worse by the penetration
ofmicro organisms, with the aid of water as a carrier,
into the relatively soft material.
Because of the high requirements of swirnming
pool coatings with regard to water-, weathering- and
colour stability, the sheetings used are stabilised
predominantly with barium-cadmium compounds. The problem
of the slimy coating formation is generally indirectly
solved by -the addition to the pool water of so-called
water-maintenance agents such as chlorine- or bromine
preparations having a strong oxidising effect. As a
direct measure it has been known to use tributyl tin oxide
as a so-called bio-stabiliser for the prevention of
fouling in swimming pool sheeting. Tributyl tin oxide,
as well as other known trialkyl tin compounds are however,
very toxic, and more particularly they have a strong
inhalation toxicity which leads ~o con~:LdQrabl~ probl@m~
for example dllr:ln~ t}le pto~luct:Lon o~ llle ~3heeting
at high processing temperatures.
As is mentioned above, the stabilising ef~ect
of diorgano- and mono organo tin compounds against the
decomposition of PVC by the effect of light, heat and
oxidation has been known ~or a long time. It has now
surprisingly been discovered that in addition such
compounds, and also certain tin salts, which until now
have been considered biocidally ineffective against a wide
--7--
~3~
variety of microorganisms such as fungi, bacteria and algae,
have a good effectiveness as anti-fouling agents i.e. agents
which counter the settling or deposition of algae, micro-
organisms and the like onto surfaces.
According to the present invention there is provided
a plastic material which comprises plasticised polyvinyl
chloride and an anti-fouling agent selected from inorganic
divalent tin salts~ monovrgano-tin compounds of formula RSnX3
and diorgano tin compounds of formula R2SnX2 in which formulae
the radicals R each represent a hydrocarbon radical, and
either
(i) each radical X represents an inorganic radical
or an organic radical other than a hydrocarbon radical,
or (ii~ two radicals X together represent an organic
radical other than a hydrocarbon radical and
any remaining radical X represents an inorganic
radical or an organic radical other than a
hydrocarbon radical,
and wherein the anti-fouling agent is present in an amount so
as to give the plastic material a tin content of from 0.05 to
1.2~ by weight.
In accordance w:ith anoth~r asp~t the present lnven-
tion provides a method for preparing a sheet or foil of plas-
ticised polyvinyl chloride having reduced susceptibility to
fouling by algae or microorganisms, which comprises providing
a plastic material which comprises plasticised polyvinyl
chloride and an anti-fouling agent and moulding said plastic
material into a sheet or foil thereof, the anti-fouling agent
being selected from inorganic divalent tin salts, monoorgano-
tin compounds of formula RSnX3 and diorgano tin compounds offormula R2SnX2 in which formulae the radicals R each represent
a hydrocarbon radical, and either
~ ,. ~ ~
~ 8 -
.. . ,.~ .
(i) each radical X represents an inorganic radical
or an organic radical other than a hydrocarbon radical,
or (ii) two radicals ~ together represent an organic
radical other than a hydrocarbon radical and
any remaining radical X represents an inorganic
radical or an organic radical other than a
hydrocarbon radical,
and wherein the plastic material contains from 0.05~ to 1.2%
by weight of tin calculated from the specified anti-fouling
agent.
The present invention particularly provides a method
for preparing a sheet or foil of plasticised polyvinyl
chloride, having reduced susceptibility to fouling by algae
or microorganisms, which comprises admixing in the presence of
one or more plasticisers, polyvinyl chloride with an anti-
fouling agent and moulding the obtained plastic material into
a sheet or foil, the anti-fouling agent being selected from
inorganic divalent tin salts, monoorgano-tin compounds of
formula RSnX3 and diorgano tin compounds of formula R2SnX2 in
which formulae th~ radicals R each represent a hydrocarbon
radical, and either
(i) each radical X reprcsents an inorganic radical
or an organic radical other than a hydrocarbon radical,
or (ii) two radicals X together represent an organic
radical other than a hydrocarbon radical and
any xemaining radical X represents an inorganic
radical or an organic radical other than a
hydrocarbon radical,
and wherein the plastic material which is formed by the
admixing step contains from 0.05 to 1.2% by weight of tin
calculated from the specified anti-fouling agent.
The use of the specified tin compounds in accordance
~-'A`' ~ - 8a -
., !f
with the invention yie`lds compositions having properties
which have low toxicity or no toxicity at all, and which are
therefore as harmless as possible to the environment. The
material, for example soft PVC (polyvinyl chloride~ which
may contain stabilisers such as barrium- cadmium compounds or
calcium-zinc compounds to give light-, weather- and heat-
resistance is preferably treated in accordance with the
invention by admixing it with the anti-fouling agent to form
a composition having anti-fouling properties. The composition
formed by carrying out the method of the invention can contain
from 0.05 (0.005) to 1.2% by weight/ more preferably from
0.1 to 0.5% by weight of tin calculated from the amount of
/
~ 8b -
~ ~3~
fou]ing agent used.
The hydrocarbon radicals R of the monoorgano and
diorgano tin compounds are preferably alkyl groups such
as methyl, bu-tyl or octyl. The radicals X may be
for example halogen, preferably chlorine, sulphur or
oxygen When X is an organic radical other than a
hydrocarbon then it may be for example an alkoxide.or
an ester radical of a saturated and/or unsaturated
carboxylic acid such as a laurate or a maleate.
It is particularly preferred to use dialkyl
tin compounds as anti-fouling agents accord:ing to the
invention. By way of examp~ethere may be mentioned
dibutyl tin dilaurate, dibutyl tin maleate, dioc-tyl
tin dilaureate, or dioctyl tin maleate. It will
be appreciated that in the general formula R2SnX2, the
two radicals ~ may simply represent a divalent group
such as maleate. Other useful dialkyl compounds
which may be mentioned are di-n-but 1 tin dichloride, di-n-
octyl tin dichloride, dibutyl tin oxide, dimethyl- or
dibutyl tin sulphid~ and dialkyl tin oxid~$. ~ o
proven to hav~ be~n ~'eec~iv@ :in accordance with
the invention are dialkyl tin alkoxides in which one
or both alkoxide groups have been replaced by dicarboxylic
acid semi esters or thio carboxylic acld esters such
as dibutyl tin methoxy maleic acid-rnethyl ester,
di-n-octyl tin diiso octyl-thioglycolate or -maleate,
dimethyl tin-diiso-octyI-thioglycolate and di-n-butyl
tin diiso octyl thio glycolate. ~ feature of the invention
is the fact that the predominant number of diorgano tin
compounds used are toxically harmless, in contrast to the
_9_
predominant number of triorgano tin compounds formerly
used for these purposes.
Mono organo tin compounds may be used to treat
materials in accordance with the invention. There
are preferably used mono alkyl tin compounds or their
polymeric form, or mono alkyl compounds in which the
radicals X represent inorganic radicals such as halogens,
sulphur or oxygen, for example n-butyl tin trichloride,
monobutyl tin oxide or monobutyl tin sulphide. As
10 with the diorgano compounds~ X may be alkoxide, or instead
one, two or three of the alkoxy groups may bé replaced
by dicarboxylic acid semi esters and/or thio carboxylic
acid esters and/or carboxylic acids, as in n-octyl tin tri
iso octyl thioglycolate or n-octyl tin-bis-iso vctyl
thioglycolate -laureate.
Of the inorganic tin salts which also surprisingly
can be used as anti-fouling agents, particular menticnis
made of tin chloride and tin sulpha-te. However a certain
water-solubility in the tin salts can be disadvantag~ous
insofar as it can lead, ~or examplc, to an ~ncr~as:lng
roughness in the sur~ace o~ a coating.
With conventional bio-s~abili.sers it is normal
to use from 0.3 to 5% by weight based on the
material to be treated. However in accordance with the
invention the tin compounds may be used to treat the
material at starting concentrations of from 0.05 to 1.2.
preferably Ool to 0.5% tin calculated from the tin
compounds added. Such proportions have been found to be
sufficient as anti-fouling agents, although this depends
on the field or area of usage and the requirements of this
field. A preferred field of usage for the invention are
--10-- .
~3~
weather-resistant products :Eormed from moulding materials
based on so~t PVC treated by the method of the invention
and optionally containing stabilisers for light-, weather~
and heat-resistance, and if necessary conventional
additives such as colouring agents, fillers and lubricants.
The treating of such materials with from 0.05 -to 1.2,
preferably 0.1 to 0.5% by weight of tin calculated -rom
the tin compounds added for anti-f'ouling, based on 100%
by weight of the moulding material, is generally
sufficient to achieve the desired effect.
The weater-resistant products based on soft PVC
treated in accordance with the invention have the
advantage of' a good light-, weather- and heat-resistance
through the use of' suitable stabilisers, preferably
based on barium-cadmium compounds or calcium-zinc
compounds or in combination wi-th other stabilisers, and
at the same time they reduce or prevent the settling
or deposition of' fouling, like algae or micro organisms.
Surprisingly, neither the light resistance, nor the
weather-resistance, nor the h~at-r~s:Lstan~e, no~ th~
workability c~P the mould:ing material or products,
is adversely a~fected by the tin compounds used
according to t~ invention. On t~ contrary, the organo tin
compounds used according to the invention generally have
as a su'bsidiary eff'ect, an unexpected improvement in
the Ba-Cd- or Cd-Zn basic stabilisation. In addition
the selected tin compounds are for the most part
toxically inactive, the majority o-i them being
toxicologically harmless and even released for use
by the health authorities.
`~` -1 1-
As mentioned above, the preferred area of use of the
invention is in the treatment of soft PVC materials.
These contain plasticisers, and require particular
stability against bio~ogical attack on the plastic~sers.
Here it is particularly surprising that the tin compounds
as de~ined, which were thought of until now as useless
against biological attack, display an anti-fouling
ef~ect. Applications of products based on soft PVC
are for example as sealing sheeting for coating or
lining swimming pools, damp areas or cooling-water
tanks, and as agricultural sheeting. The plasticisers
which may be included in the PVC material are pre~erably
esters o~ polybasic acids with monovalent alcohols,
such as phthalates, es-ters of adipic acid and sebacic
acid, trimellitic acid esters, or para~fin-sulphonic
acid phenyl/cresyl esters. Preferab1y from 15 to 50%
by weight of plasticiser is used based upon the total
weight o~ the composition.
PVC is not usually plasticised merely by th~
addition of low molccular w~ h~t pla~;t~ r~; u~ually
high polymer plasticising additives such as ethylene
vinyl acetate, ethylene vinyl acetate copolymers or
chlorinated polyethylene are included. The moulding
materials which are treated by the method of the
invention preferably contain from 20 to 8~/o by weight
of high polymer plasticising additives based on 100%
by weight of moulding material. It is pre~erred, though,
that the plasticisexs and high polymer additives together
do not amount to more than 80% by weight of the moulding
material.
Materials treated by the method of the invention may
-12-
be moulded into furnished products such as sealing sheeting
based OD soft PVC, ~or the coating of water-containing
receptacles or the like.
As may be seen ~rom the ~ollowing Examples very
good results have been achièved in accordance with
the invention. Thus the protective e~fect
of the prevention o~ fouling for example in swimming
pool sheeting and the prevention of formation of slimy
surface coatings was practically as good as that o~
the known triorgano tin compounds, in particular of the
hitherto preferably used trialkyl tin compounds. However,
the anti-fouling agents of the invention have the
advantage over hitherto used biostabilisers that they are
substantially less toxic or not at all toxic. In addition
because of the required extreme light- and weathering-
resistance and the low water absorption, sealing sheeting
which comes into contact constantly with water, is
stabilised predominantly with barium-cadmium compounds
or calcium-zinc compounds or i~ necessary combinations o~
these with ~urther stabili~ers. It i~ also surprl~ng
that the anti~ouling agents o~' th0 invention d:l~play
a par-ticularly good e~fectiveness on PVC moulding
materials with a very high content of plasticiser.
A iurther feature of sealing sheet based on a
material treated according to the invention which is used
as swimming pool sheeting, is that a low concentration
o~ maintenance additive is required to keep the water
clean. In contrast,normally a speci~ic amount
o~ maintenance agent is necessary to keep the water clean
3~ and clearland in swimming pools with little water movement
-13-
a coating inevitably forms on the sheeting. In order
to avoid this, the maintenance agents are o~ten added
in excess. In addition to the strong annoying smells,
this may be harmful to the skin and in particular for the
eyes, and also harmful to the sheeting itself which may
age prematurely.
-14-
'~F
Thé inven-tion is illustrated by the following
Examples.
Comparison Example 1
A soft PVC sheet was produced by calendering
(extruding) a mixture of the following: 100 parts
by weight ofs(suspension)PVC, 62 parts by weight of a
C8-C10 alkyl phthalate plasticiser, 3.3 parts by
weight of epoxidised soya oil, 4 parts by weight of a
commercial,liquid Ba/Cd stabiliser containing 6%
by weight of cadmium, and 7.8 parts by weight of
conventional anti-oxidants, screening agents and dye
(colour) pigments. The sheet thus produced
was stored at room temperature in tap water, and after
7 days it was found that a slimy coating had ~ormed
on the surface of the sheet. This coating consisted
of micro organisms sticking to the sheet, and corresponded
in the practical case o swimming pools to the starting
point or origin of a progressive deterioration in the
quality of the water as the micro organisms increased
correspondingly. In :~ct th~ coat~.ng gr~w s~ron~r on
further storage of the sh~et in tap wat~r, and after 60
days formed a layer thickness o~ about 0.5 mrn. The coating
-itsel~ was slippery-slimy, and had an unpleasant i'eel.
C'omparison Example 2
The procedure of Comparison ~xample 1 was repeated,
except that the composition used to form the sheeting
additionally included 1.2 parts by weight of tributyl
tin oxide No coating had been formed on the surface of
the sheet after storage in tap water at room temperature
for 14 days. In fact not until 60 days storage in tap
water at room temperature did a barely perceptible
-15-
slippery thin coating form on the surface of the sbeet;
this slightly strengthened during the next 30 days
storage. Aftcr further stora~e there again occurred the
formation of a coating which grew thicker. The
disadvantage of this known biocidal material is its
high toxicity, which greatly restricts its application
possibilities.
Example 3
A composition was prepared as in Comparison Example 1
except that there was additionally included 2.43 parts by
weight of a commercial dibutyl-tin-dithio glycolate;
this proportion corresponded to 0.4 parts by weight of -tin
(0.23~ by weight of tin based on the composition as
a whole). From this composition, as in Comparison Example 1,
a sheet was produced which was tested in the same way.
After 14 days storage in water the sheet was still
completely coating-free and after 60 days a barely
perceptible coating had formed.
Example 4
A composition was prepared as in Comparison Example 1
except that there was additionally included 0.5 parts by
weight oi thelinorganic Sn-salt, SnC12, corresponding to
0.31 parts by weigh-t Sn (0.17% by weight of Sn based on
the composition as a whole). ~rom this composition, as
in Comparison Example 1, a sheet was produced and tested
under the same conditions. After 14 days storage the
sheet was still completely coating free. After 60 days
the sheet showed a slimy coating which was still less
substan-tial than the sheet of Comparison Example 1 had shown
.
-16-
~3~
after 7 days.
Example 5
The procedure of Comparison Example 1 was repeated
except that the composition included 1 part by weight of
a liquid dibutyl tin maleic acid ester, which corresponds
to 0.19 parts by weight of Sn (0.11% by weight of Sn
based on the composition as a whole). The sheet produced
was tested under the same conditions as in Comparison
Example 1 and showed the same be.haviour as the sheet
according to Example 3.
Comparison Example 6
A sheet was produced by extrusion from a
composition cons:isting of 100 parts by weigJht o~
PVC, 96 parts by weight of ethylene vinyl acetate
copolymer, 6 parts by weight of epoxidised soya oil,
6 parts by weight of a liquid barium-cadmium stabiliser
(with 6% by weight o~ cadmium) and 9.8 parts by weight
of conventional anti-oxidants, screening agents and colour
(dye~ pigments. The sheet was tes~ed under th~ same
conditions as in Comparison Examp:lo 1, ~nd ~;howcd
very similar behaviour ln its coating l'ormation to the
sheet according to Compari.son Example 1.
Example 7
A composi-tion was -~ormed as in Comparison Example 6,
except that there was included 1 part by weight o~ liquid
dibutyl tin maleic acid ester, which corresponds tu 0.19
parts by weight of Sn (0.09% by weight of Sn based on the
composition as a whole). A sheet was produced ~rom this
composition as in Example 5, and on testing showed the
same behaviour as the sheet of Example 4 with respect to
-17-
coating formation, i.e. settling of micro organisms.
Example 8
The procedure o-.f ~xample 7 was repeated except
that 2 parts by weight of the liquid dibutyl tin maleic
acid ester were incorporated. On testing it was found that
the sheet produced was even less prone to coating ~ormation
after 60 days storage in water than the sheet of Example 7,
i.e. it was still practically coating-free and was
hardly slippery. From this it rnay be concluded that a
higher content of active su~stance according to the
invention shows a better and longer lasting e~ectiveness
~or the prevention of fouling, i.e. ~or preventing the
formation of' slimy/slippe~ coa-tings on the sheet.
Example g
To a composition according to Comparison Example 1
were added 3.5 parts by weight of n-butyl-tin- tri iso octyl
thio glycolate, which corresponds to 0.53 parts by
weight of tin (0.29% by weight of tin based on the
composition as a whole). A shec~t w~s produ~ nd t~.Jt~d
under the same conditi.ons as i.n Compari~on Ii,xarnple 1. This
behaved similarly in its coating formation as the ~heet
according to Example 7.
The following Table summaris~ the coating ~orrnation
properties of the sheets according to the Examples over
a period of up to 90 days. The code numbers 0-4 as used
in the Table correspond to the following results:
O no coating
1 hardly perceptible coati.ng
2 slight coating
3 slippery coating
4 thick slippery coating
-18-
Example (coating value code)
Duration o~ test 1 2 3 4 5 6 :7 8 9
(days)
.. . 7 3 0 0 0 0 3 0 0 0
.. . .. ..
14 4 0 0 0 0 3 0 0 0
28 4. 0 0 1 0 4 1 0
4 1 1 2 1 ~ 2 1 2
4 2 2 2 2 4 2 2 2
EXAMPLE 10
A sheet is manufactured by extrusion from a formula
tion of 100 parts by weight of sequence ethylene-propylene-
polymer (buna*AP447 - Chemi~ch~ Werke l:luels), I.0 parts by
weiyht of polyethylen~ 90 parts b~ w~i.ght of chalkt 10 parts
by weight of epoxidized soybean oi.l, 0.3 parts by weight of
a lubricant, 0-6 parts by weiyht o liyht protection ayent,
4 parts by weight of T102*and 0.5 parts by weight of color-
ing pigments. The sheet is tested under the conditions
described in Example 1. This sheet shows a very similar be-
havior in plaque formation as the sheet of Example 1.
* Trademark
--19--
~ ~3~
EXAMPLE 11
-
A foxmulation acco~din~ to Example 10 was co~bi~ed
with 2 parts by weight o~ dibutylin oxide~ A sheet is produc-
ed from this formulation as in Example 10, and tested~ This
sheet shows a better behavior regarding prevention of plaque
formations, I.E. establishment of microorganisms and first
slight plaque is formed on the surface after 28 days of test-
ing in tap water, same behavior as sheet of Example 3.
-20-
