Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
LZZ88~:)7
3-14133/CGM 277/+
Mixtures having biocidal activity
The present invention relates to mixtures having
biocidal activity and containing an organotin compound or a
tin halide and a phosphonium halide, the use of these mix-
lures as besides, and a process for solubilising organotin
compounds in water.
It is known that triorganotin compounds, in portico-
far organotin oxides, can be used as besides, and their
importance has increased continually in recent years. For a
long time it was only possible to use such substances as
solutions in organic solvents. Their applicability was
therefore limited for technological and ecological reasons.
There was therefore a need to be able to employ besides
having a similar activity, but soluble in water. The use of
organotin compounds together with ammonium salts in aqueous
systems was suggested in British Patent Specification
1,467,420 as a means of increasing the volubility in water.
However, this method is not entirely satisfactory; in many
cases only dispersions are formed, which makes it necessary
to use organic solvents concomitantly, or there is hardly
any increase in the sealability in water, or none, which is
relevant, for example, to solubilising organotin fluorides.
In other cases, although the organotin compounds are disk
solved at low concentrations, the solutions prove unstable.
The combination tetradecyltriphenylphosphonium
chloride/TBT0 is suggested for use in industrial cooling
water systems in a data sheet of the firm Carlisle
The present invention relates to mixtures containing
a) at least one organotin compound of the formula I and/or
aye
-- 2
II and/or VI
L R3Sn ¦ X (I), R3Sn-Y-SnR3 (II), Sol My (Al),
in which n is 1, 2 or 3, r and t independently of one another
can assume values from O to 4, it being necessary for the
total (rut) to be 4, L and M independently of one another are
fluoride, chloride, bromide, iodide, cyanide, Senate or
thiocyanate, X is the anion of an n-basic inorganic acid or
an n-basic carboxylic acid or is -OH, Y is oxygen or sulfur
and R1 is C1-C6-alkyl which is unsubstituted or subset-
tuned by hydroxyl, cyan or halogen, C3~C7-cycloalkyl,
phenol or 2-methyl-2-phenylpropyl, and
b) at least one phosphonium compound of the formula III
~R3PR~l Q ( I I I )
in which R2 can be as defined for R1 and R3 is C1-C22-
alkyd, C8-C22-alkyl which is substituted by hydroxyl or color-
inn C8-CzO-alkylbenzyl or a group of the formula lo -Z-PR23
(IV) in which R2 is as defined above and Z is a linear or
branched (CVH2v) group, v being a number from 2 to 22
and it being possible for this group to be interrupted once
or several times by -O-, -S-, -OX-, -coo- -N(R)- in
which R is hydrogen or C1-C4-alkyl and Q is a halide, the
combinations III:I or IVY or III:II being present in the
mixture in a molar ratio of at least no or at least 1:1 or
at least 2:1, respectively; and R2 must not be phenol if
the mixture consists of the phosphonium compound III in
which R3 is C1-Cz2-alkyl and of the organotin compound
of the formula II in which R1 is n-butyl and Y is oxygen.
Examples of R1 and R2 as C1-C6-alkyl and of
R3 as C1-C2z-alkyl are linear or branched alkyd radicals,
such as methyl, ethyl n-propyl, isopropyl, n-butyl, sec.-
bottle, tert.-butyl, namely, isoamyl, n-hexyl, n-octyl,
~L2;~:8~
2-ethylhexyl, decal, undecyl, dodecyl, tridecyl, tetradecyl,
hexadecyl, octadecyl, eicosyl or docosyl. The invention also
relates to mixtures of such alkyd groups as tetradecyl and
hexadecyl. R3 is preferably C8-C18-alkYl, especially
C12 Colloquial
It is also preferable for R1 and R2 independently
of one another to be C1-C6-alkyl, especially n-butyl.
Examples of R1, R2 and R3 as C1-C6-hydroxyalkyl
are methylol, 2-hydroxyethyl, 4-hydroxylbutyl or 6-hydroxy-
Huxley, preferably methylol~
As C3-C7-cycloalkyl, R1 and R2 are especially
cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl or cycle-
hotly, preferably cyclohexyl.
Examples of R3 as substituted C8-C22-alkyl are
8-chlorooctyl, 4-chlorooctadecyl, 10-hydroxydecyl or 20-
hydroxyeicosyl.
R3 us preferably C8-C20-alkylbenzyl and can be sub-
stituted, for example, on the phenol ring by methyl, ethyl,
Huxley, decal, dodecyl, sec.-butyl, tert.-butyl or
isoamyl.
If R3 is a group of the formula IV, Z is, for
example ethylene, 1,3-trimethylene, 1,4-tetramethylene,
prOpylidene, -CH2CH2-0-CH2cH2-~ (C~20)4cH2cH2 '
-CH2CH2-NH-CH2CH2-~ -CH2CH2 N(CH3) CH2CH2
-CH2COOCH2cH2
Examples of R as C1-C4-alkyl are methyl, ethyl,
n-propyl, isopropyl, n-butyl, sec.-butyl or t.-butyl.
Examples of X as the anion of an inorganic acid are
fluoride, chloride, bromide, iodide, cyanide, Senate, trio-
Senate, nitrate, sulfate, phosphate thiophosphate or born
ate. The preferred anions are fluoride and chloride.
As a carboxylate anion, X is the anion of an n-basic
carboxylic acid, for example format, acetate, preappoint,
acrylate, methacrylate, hexanoate, subacute, naphthenate,
abietate or citrate.
n is preferably 1.
Y is preferably oxygen.
1~2~80~
-- 4 --
Mixtures in which the compound of the formula I is
tributyltin chloride or fluoride are particularly preferred.
Mixtures in which the compound of the formula II is
d;-(tributyltin) oxide are also of interest.
R2 in the formula III is as defined for R1 in the
formulae I and II, but, within the definitions given, R1 and
R2 in a mixture according to the invention can be entirely
different.
As a halide, Q is fluoride, chloride, bromide or
iodide, preferably fluoride and especially chloride.
In order to syllables 1 mow of a compound of the
formula I [Risk] X to an adequate extent it us advantageous
if the mixture contains at least n mow of the compound of
the formula III, whereas in the case of compounds of the
formula VI at least 1 mow of the compound of the formula III
per mow of the compound VI is adequate.
As a rule, a twice molar amount of a compound of
the formula III is sufficient to give excellent results with
the compounds of the formula II. If desired, the compound
III can, of course, also be employed in a large excess in the
mixture, for instance on a molar ratio of 50:1. In order to
obtain a good biocidal action, in practice mixtures of come
pounds of the formula III and I or III and VI or III and II
are employed in a molar ratio of no to 20:1 or of 1:1 to
20:1 or of 2:1 to Z0:1, respectively, preferably no to 12:1
or 1:1 to 12:1 or 2:1 to 12:1, respectively.
Preferred mixtures contain at least one or~anotin
compound of the formula I and/or II in which X is fluoride,
chloride, bromide, iodide, cyanide, Senate, thiocyanate,
nitrate, sulfate, phosphate, thiophosphate, borate, format,
acetate, preappoint, acrylate, methacrylate~ hexanoate,
naphthenate, subacute or hydroxide, R1 is C1-C6-alkyl,
methylol, cyclohexyl, phenol or 2-methyl-2-phenylpropyl,
and also contain at least one phosphonium compound of the
formula III in which R2 can be as defined for R1 and R3 is
~X~:8~r'
I
-- 5
C8~Cz2-alkyl which is unsubstituted or substituted by
hydroxyl or chlorine, or is C8-Czo-alkylbenzyl, and in which
Q is fluoride, chloride, bromide or iodide; R2 must not be
phenol if the mixture consists of the phosphonium compound
III in which R3 is C8-C2z-alkyl and of the organotin
compound II in which R1 is n-butyl and Y is oxygen.
Particular interest attaches to mixtures containing
compounds of the formulae I and/or II and/or VI and III in
which n is 1 and X and/or L and/or M are fluoride or color-
ides Y is oxygen and R1 and R2 independently of one another
are C1-C6-alkyl or phenol, and R3 is Cg-C18-alkyl or
Cg-Czo~alkylbenzyl and Q is chloride or fluoride; in this
case RZ must not be phenol if the mixture contains a come
pound of the formula II on which R3 is C8-C18-alkyl, R1
is n-butyl and Y is oxygen.
Mixtures which are particularly preferred contain at
least the compound tri-n-butyltetradecylphosphonium chloride
and the compound di-(tri-n-butyltin) oxide.
Mixtures which are also preferred contain at least
the compound tri-n-butyltetradecylphosphonium chloride and
the compound tri-n-butyltin chloride.
Mixtures which are also of interest contain at least
the compound tri-n-butyltetradecylphosphonium chloride and
the compound tri-n-butyltin fluoride.
Mixtures which also deserve consideration contain
at least the compound tri-n-butyltetradecylphosphonium color-
ire and the compound triphenyltin hydroxide.
Preferred mixtures contain at least the compound
tri-n-butyl-tetradecylphosphonium chloride and the compound
triphenyltin acetate.
The following are examples of compounds of the for-
mute I:
1. Tr;methyltin chloride
2. Tri-n-butyltin fluoride
3. Tri-n-butyltin chloride
4. Tri-n-butyltin acetate
5. Tri-n-butyltin acrylate
I 307
6, Tri-n-butylt;n methacrylate
7. Tris-tri-n-butytin phosphate
8. TricycLohexyltin chloride
9. Triphenyltin chloride
10. Triphenyltin fluoride
ll.Di-n-butyl-propyltin chloride
1Z. Tri-n-butyltin naphthenate
13. Triphenyltin hydroxide
14. Tricyclohexyltin hydroxide
15. Tri-n-butyltin bonniest
16. Tri-n-butyltin cyanide
17. Tri-n-butyltin thiocyanate
The following are examples of compounds of the for-
mute II:
18. Di-(trimethyltin) oxide
19. Di-(tri-n-butyltin) oxide
20. Di-(tri-n~butyltin) sulfide
21. Di-(tr;cyclohexyl) oxide
22. D;-(tr;cyclohexyl) sulfide
23. Di-(triphenyltin) oxide
24, D;-(triphenyltin) sulfide
25. Di-(tri-n-propyltin) oxide
26, Di-(tricyclohexyltin) oxide
The following are examples of compounds of the
formula III:
27. Tri-n-butyl-n~dodecylphosphonium chloride
28. Tri-n-butyltetradecylphosphon;um chloride
29. Tri-n-butyl-n~decylphosphonium chloride
30. Tri-n-butyl-n tctradecylphosphonium bromide
31. Trimethylol-p~laurylbenzylphosphon;um chloride
32, Tri-n-butyl-~n-laurylphosphonium chloride
33. Tri-n-butyl-n-laurylphosphonium bromide
34. Tri-n-butyl-n-hexadecylphosphonium chloride
35. Tri-n-butyl-n~dodecylphosphonium bromide
36. Tri-n-butyl-p~laurylbenzylphosphonium chloride
37. Triphenyl-n-tetradecylphosphonium bromide
38. Triphenyl-n-octadecylphosphonium bromide
~22~380~
39. Triphenyl-n-dodecylphosphonium fluoride
40. Triphenyl-n-dodecylphosphonium chloride
The following are examples of compounds of the for-
mute VI:
41- Tin tetrachloride
42. Tin tetrafluoride
43. Tin tetrabromide
44. Tin tetraiocdide
Good results are achieved with mixtures of the
following compounds: (2+34), (2+27), (18+28), (2+29), (3+28),
(19+28), (12+28), (2+37), (2+38), (28+41) and (2+30).
The tar, salts of the formula I, II and VI are common-
Cole available products. The phosphon;um halides of the
formula III are also commercial products or can be prepared
by known methods from the corresponding phosph;nes and an
organic halide.
The invention also relates to the use of a mixture
Courtney at yeast one organot;n compound of the formula I
ardor II and/or VI and at least one phosphon;um halide of
the formula III as a buzzed.
The mixtures according to the invention provide a
broad spectrum of action for the control of animal and plant
pests, leading to many different possible uses, for example
as bactericide or disinfectants, against the formation of
slime in paper manufacture and as fung;c;des, insecticides,
acaricides, herbicides and alg;cides. In add ton the
novel substances are excellently suitable for use as incus-
trial antimicrobial agents for the protection of materials,
for example for protecting wood, cellulose and paper, text-
ties and leather, dyes, pants ant fouling paints and
smiler coating substances, optical glass and other types of
glass, cooling water, plastics, rubber and adhesives, drooling
and cutting oils, petroleum, lubricants, waxes and fuels and
other materiels
In particular, the mixtures according to the oven
ton can also be used for protecting biodegradable plastics
and plastics compositeness, preferably for protecting
~L;22~
plasticized polyvinyl chloride or polyvinylidene chloride.
Depending on the purpose for which they are used,
the compounds are employed in the concentration ranges known
to those skilled in the art. The limits of the customary
concentrations are given by the following values: whereas
in cooling water concentrations as low as the Pam range are
sufficient, in anti-fouling formulations concentrations of
up to 40 X by weight are customary.
A preferred field of application is constituted by
protective coating agents, particularly anti-fouling paints,
which are based on organic materials and, besides the custom-
cry primary materials and additives, contain 0.5 - 60 % by
weight, preferably 3 - 40 % by weight and especially 8 - 25 X
by weight, based on the total mixture, of a compound of the
formula I or mixtures thereof.
Customary primary materials for anti-fouling paints
are the paint raw materials designated binders and known to
those skilled in the art, such as natural and synthetic
resins, homopolymeric and copolymeric products containing
the monomers vinyl chloride, vinylidene chloride, styrenes
vinyltoluene, vinyl esters, acrylic acids and methacrylic
acid and esters thereof, and also chlorinated rubber, natural
and synthetic rubber, if appropriate chlorinated or cyclised,
and also reactive resins, such as epoxide resins, polyurethane
resins and unsaturated polyesters which can, if desired, be
converted into film-forming, higher-molecular products by
the addition of curing agents.
The binders can be liquid or can be present in soul-
lion. In the case of dissolved binders, including thcrmo~
plastics, a protective film can also be Formed by the vapor-
anion of the solvent. Solid coating agents can, for example,
be applied to articles by the powder coating process. Fur-
then examples of customary primary materials are tar, mod-
liens, dyes, inorganic or organic pigments, fillers and
curing agents.
The use of the mixtures according to the invention
as aqueous solutions or solutions containing water in the
~LX2~ 7
_ 9 _
protection of materials, in particular in disinfectants, in
water treatment, in wood preservatives and in anti-fouling
paints is, however, to be particularly emphasized.
The buzzed mixtures which can be used in accordance
with the invention can also contain further active substances.
The following are examples of these:
a) Organosulfur compounds, for example ethylene dithiocyan~
ate (MET) or 3,5-dimethyltetrahydro-1,3,5-2H-thiadiazine-2-
throne (DMTT). Substances of this type are employed in paper
manufacture, particularly against the formation of slime.
b) Chlorinated phenols, such as sodium pentachlorophenate.
Compounds of this type are distinguished by a broad spectrum
of action.
c) Copper salts, such as copper sulfate, in small quantities
are effective algicides.
d) 2,2-Dibromo-3-nitrilopropionamide (DBNPA) as an algicide,
fungicide and bactericide.
e) Chlorine and bromide are known, effective algicides and
bactericide which are used particularly in water treatment.
f) Chlorine dioxide, chloroisocyanurates and hypochlorites
are also customary besides in water treatment.
g) Known wood besides
91. Salt mixtures based on: silicofluorides, hydrogen
fluorides, inorganic boron compounds, chromates, fluorides,
arsenic (oxide or arsenates), a copper salt (sulfate or
naphthenate), tin and zinc salts and mercury compounds.
9 . Tar oil preparations
93. Organic active compounds: pentachlorophenol, phenol,
DOT, dieldrin, London or gammexane and chlorinated nap-
thalenes.
h) Known disinfectants:
Phenol or phenol derivatives, formaldehyde and/or
other aldehydes or derivatives, chlorine and organic or on-
organic substances containing active chlorine, amphoteric
surfactants.
i) In addition, it has proved particularly advantageous to
use the mixtures according to the invention together with
2~380~
- 10 -
ammonium halides of the formula V:
[ R (R NO OR Q (V)
on which Q us halogen and R4 and R5 independently of one
another are hydrogen, C1-C6-alkyl, C1-C6-hydroxyalkyl or
a polyglycol radical having a degree of polymerization of 2
to 25 and R6 us hydrogen, hydroxyl, C1-C6-alkyl, C1-C6-
hydroxyalkyl, glycidyl, C1-C6-halogenoalkyl, phenol, bouncily,
Cg-C22-alkylben7yl, monochlorobenzyl, d;chlorobenzyl,
monon;trobenzyl, d;nitrobenzyl, trimethoxys;lylpropyl or in-
ethoxysilylpropyl, and R7 is Cg-C2z-alkyl, a polyglycol
radical having a degree of polymerization of 2-25, R8-phenoxy-
ethoxyethyl, R8-C(O)NH-(CH2)m or R8-0-phenoxyethoxyethyl
in which R8 is C1-C12-alkyl and m is 2 or 3, and R7 is
also a group of the formula VII -Z-(R4)N(R5)R6 in which Z
us a linear or branched (CvHzv)group in which v is a
number from 2 to 22 and R4, R5 and R6 are as defined above
and, in addition, two of the radicals R4, R5, R6 and R7,
together with the nitrogen atom to which they are attached,
form a saturated or partially unsaturated heterocycl;c rung
which is unsubstituted or substituted by one or two methyl or
ethyl groups, or three of the radicals R4, R5, I and
R7, together with the nitrogen atom to which they are
attached, form an unsaturated heterocyclic ring which is us-
substituted or substituted by one or two methyl, ethyl,
hydroxyl or acutely groups.
Examples of R4, R5 and R6 as C1-C6-alkyl are
linear or branched alkyd radicals, such as methyl, ethyl,
n-propyl, isopropyl, n-butyl, sec~-butyl, namely, i50amyl or
n-hexyl.
Examples of R4, R5 and R6 as C1-C6-hydroxy
alkyd are methylol, 2-hydroxyethyl, 3-hydroxypropyl or 6-
hydroxyhexyl.
Examples of R6 as C1-C6-halogenoalkyl, preferably
C1-C2-halogenoalkyl are chloromethyl, 2-bromoethyl or
6-chlorohexyl. Halogen is preferably chlorine. Radicals
such as 2-hydroxy-3-chloropropyl should also be mentioned.
~X2880~
R6 is substituted or unsubstituted bouncily, such as
o-, m- or p-methylbenzyl, 2,3-, 2,4-, 3,4- or 2,5-dimethyl-
bouncily, nonylbenzyl, laurylbenzyl, tetradecylbenzyl, o-, m-
or p-chlorobenzyl, 2,3-, 3,4-, 3,5- or 2,5-dichlorobenzyl,
o-, m- or p-nitrobenzyl or 2,3-, 3,4-, 3,5- or 2,5-d;nitro-
bouncily.
As Cg-c22-alkyl~ R7 can be n-octyl, 2-ethyl-
Huxley or branched or unbranched nonyl, decal, undecyl, do-
decal, tridecyl, tetradecyl, hexadecyl, octadecyl, eicosyl
or docosyl.
Examples of R8 as C1-C12-alkyl are methyl, ethyl,
n-propyl, n-butyl, sec.-butyl, n-hexyl, n~octyl, 2-ethyl-
Huxley, 1,1,3,3-tetramethylbutyl or unbranched or branched
nonyl, decal or dodecyl.
If two of the radicals R4, R5, R6 and R7,
together with the nitrogen atom, form a saturated or partially
saturated heterocylic ring which is unsubstituted or subset-
tuned by one or two methyl or ethyl groups, this is, for
example, pyrrolidine, piperidine, 2-methylpiperidine, piper-
amine, Z,5-dimethylpiperazine or morpholine.
If three of the radicals R4, R5, R6 and R7,
together with the nitrogen atom, form an unsaturated hotter-
cyclic ring which is unsubstituted or substituted by one or
two methyl or ethyl groups, this can be pardon, 4-methyl-
pardon, quinoline, pyrimidine, thiazole, imidazole, ox-
zone, 2-hydroxypyridine or 4-acetylpyridine.
Compounds of the formula V can be employed in a
molar ratio of û:1 to 50:1, preferably up to 6:1, based on
the compounds of the formula I or II or VI. Preferably, the
molar ratio of the sum of the compounds of the formula III
to the compounds of the formula I is no to 12:1, to the
compounds of the formula II is 2~1 to 12:1 and to the come
pounds of the formula VI is 1:1 to 12:1.
In addition, further substances and assistants such
as are customarily used concomitantly in such preparations
can, of course, also be present in such formulations. En-
apples of these are cat;onic or non ionic surface-active
~8~307
- 12 -
substances, electrolytes, completing agents, solubilisers
and dyes and perfumes. These additives are used, for example,
to improve the wetting power and the resistance to hardening,
to adjust the viscosity and to increase the stability to
cold conditions of the solutions.
The invention also relates to a process for soul-
bilising compounds of the formula I and/or II and/or VI in
water, wherein the aqueous medium contains at least one
compound of the formula III, the molar ratio of the compounds
of the formulae III:I and IVY being at least no and 1:1,
respectively, and the ratio of the compounds of the formulae
III to II being at least 2:1.
The precise mechanism of action of the solubilisation
is not known, but it can result in an interaction between
the compounds of the formulae III and I and/or II and/or VI,
which can, for instance, be compared with a salvation effect.
It is particularly advantageous for the transport
of aqueous systems containing besides if these systems con
lain the besides dissolved in high concentrations. These
systems are diluted by the final consumer to the concentra-
lion desired for the particular application or, in many
cases, are employed as such. The present invention also
relates, therefore, to aqueous systems containing at least
one organotin compound of the formulae I and/or II and/or VI
and at least one compound of the formula III, the molar
ratio of the compounds of the formula III:I or IVY being
at least no or 1:1, respectively, and the ratio of the come
pounds of the formulae III:II being at least 2:1.
These solutions contain about 0~1 to US mow X of
the compound of the formula I or of the formula VI, about
0.1 to 3 mow % of the compound of the formula II and about
0.1 to 6 mow % of the compound of the formula III.
The concentration us selected within these approx;-
mate limits, depending on the end use. Thus in wood preserve
anion, for example, high concentrations are of interest,
whereas lower concentrations can also be selected for water
treatment.
~.Z~38~7
The invention is illustrated in greater detail in
the examples below.
Example 1: Di-(tributyltin) oxide (compound 19) is added
at 30C to an 80% aqueous solution of tributyltetradecyl-
phosphonium chloride (compound 28). This mixture is shaken
continuously for 24 hours. A check is then made to see
whether the whole quantity of tributyltin oxide has disk
solved.
It is possible in this way to dissolve 8.4 mow % of
the compound (19), whereas the final concentration of the
compound (28) is 9.2 mow %. The same final concentration
of (19) is obtained of a 40% aqueous solution of (28) is
used initially.
Example ?: Using an experimental procedure analogous to
that in Example 1, except that the compound (19) is replaced
by (compound 3), 3.8 mow % of tributyltin chloride can be
dissolved, the final concentration of the compound (28) being
15.3 mow %.
Example 3: Using an experimental procedure analogous to
that in Example 1, except that the compound (19) is replaced
by (compound 2), 2.9 mow of tributyltin fluoride can be
dissolved, the final concentration of the compound (28)
being 16.7 mow %. The same result is also obtained using a
40% solution of t28).
Examples 4-7: The following results are achieved (final
concentrations) analogously to Example 1:
En- P compound Sun ~omppund
ample _ _ _ _ __ ___ _
No. No. (I ) by (Lyle%)
78 139,2 l22 2 9
6 27 17,9 2 2,9
7 30 15,9 2 1'5~___ _
122~3~307
- 14 -
Example 8: Test of activity in cooling circuits.
The cooling circuits, which are in the open natural
solar radiation, entry of dust and effects of weathering),
consist of:
a) a plastics vessel having a volume of 113 liters and an
overflow,
b) a pump (21 litres/minute at a head of 3 m) and
c) a cooling tower equipped with boards of Oregon (swooped),
Oregon (heart wood), oak, spruce, asbestos cement and PUKE.
The inflow of fresh water was adjusted to such a rate
as to compensate for the loss through spray and evaporation,
and the besides were diluted in a ratio of approximately
1:Z in 24 hours.
The cooling circuits are infested as the result of
natural entry of dust and not by deliberate inoculation.
To prevent the formation of slime and the growth
of algae, the cooling Crockett us treated with:
1. 50 ppm/week or 25 ppm/week of an aqueous formulation con-
tanning 35 % of the compound 22 and 5 % of the compound 3
in H20, and
2. 21 Pam twice a week of a solution containing 45 % of the
compound 28 and 5 % of the compound 19 in water.
The test was evaluated by observing the growth on the
boards visually.
The circuit which had been treated at 50 ppm/week for the
first three months and at 25 Pam for the next two months, and
the circuit which had boon treated At 2]. porn Willis a week
exhibited no sign at all of incipient slime Formation and
growth of algae. A solution of the phosphon;um compound 28
employed on its own on these concentrations and at this ire-
quench would not completely suppress the growth of algae
for thus period of tome.
Example 9: Growth on wood
Small blocks of spruce wood, 7 x 10 x 10 mm in size,
3L2~88Q~
- 15 -
were dried for 30 minutes in vacua. The blocks were then
vacuum impregnated by keeping them in vacua for 30 minutes
in 100 my of distilled water and buzzed and then subjecting
them in the water to a pressure treatment (2 atmospheres
gauge applied by compressed air) for 18 hours. The pieces
of wood treated in this way were first subjected to leaching
in running water and were then dried.
The dried pieces of wood were laid on potato-glucose
ajar, and the wood and the surrounding ajar were inoculated
with 0.1 ml of a spore suspension of a mixed culture of
Aspergillus Niger Apergillus Phoenicia, Penicillium fun-
culosum, Alternaria alternate, Cladosporum cladasporoidis,
Aureobasidium pullulans and Cheetomium globusum (1~1+1 etc.).
After the wood had incubated for 4 weeks at 28C, growth was
evaluated in accordance with the following rating:
1 = growth on the wood
2 = slight growth on the wood
3 = no growth on the wood
4 = no growth on the wood and inhibitory zone
of 1 % of Growth after storage Growth after story
compound compound in water for 1 week age in water for
4 weeks
28 3 4 4
28 2 4 4
The excellent action of the formulations in preserve
in wood even after storage in water, can be seen from the
table.
