COMPOSITIONS SOLIDES A BASE DE SILICONE BIOLOGIQUEMENT ACTIVES EN AGRICULTURE

SOLID SILICONE COMPOSITIONS HAVING AN AGRICULTURAL BIOLOGICAL ACTION

Abrégé anglais

Company called: RHONE-POULENC AGROCHIMIE
SOLID SILICONE COMPOSITIONS HAVING AN
AGRICULTURAL BIOLOGICAL ACTION
ABSTRACT
Solid compositions having an agricultural
biological action. They comprise a matrix of silicone
elastomer in which a water-soluble active substance
having an agricultural biological action and a water-
soluble auxiliary agent are dispersed.
Application in agriculture.

Revendications

64
CLAIMS
1. A solid, polymer-based composition
having an agricultural biological action in order to
promote the growth of plants, consisting of a
predominant amount of a silicone material, which is not
crosslinked or at least partially crosslinked and is
permeable to water vapour, and an active substance
which has an agricultural biological action and is
slightly soluble in water, dispersed homogeneously in
the silicone material and not having an inhibitory
effect on the crosslinking of the silicone, the
silicone material and the water-soluble form of the
active substance being such that the release kinetics
of the active substance by the silicone material in a
non-liquid, in particular an optionally divided solid,
medium or in a gaseous medium is essentially of the
order of zero, in which composition the active
substance chosen has a solubility in water of at least
0.5 g/l and which composition also contains a water-
soluble auxiliary agent such that its dispersion is
homogeneous in the silicone material and such that its
presence does not inhibit the crosslinking of the
silicone and promotes release kinetics of the active
substance by the silicone material, in a non-liquid, in
particular an optionally divided solid, medium or in a
gaseous medium, essentially of the order of zero.
2. The composition according to claim 1,
wherein the system comprising the active substance and

the auxiliary agent is present in an amount of 5 to
50 parts per 100 parts of organopolysiloxane starting
material.
3. The composition according to claim 1,
wherein the active substance is present in an amount of
15 to 40 parts by volume per 100 parts by volume of
organopolysiloxane.
4. The composition according to one of
claims l to 3, wherein the active substance/auxiliary
agent ratio is between 1/10 and 10/1.
5. The composition according to claim 4,
wherein the active substance/auxiliary agent ratio is
between 1/5 and 5/1.
6. The composition according to one of
claims 1 to 5, wherein the silicone matrix is a
silicone composition comprising (A) a diorganopoly-
siloxane gum and (B) a reinforcing filler (B1) and/or an
organic peroxide (B2).
7. The silicone composition according to
claim 6, wherein the compound (B1) is a siliceous
reinforcing filler.
8. The composition according to one of
claims 6 and 7, which comprises:
- (A): 100 parts by weight of a diorganopolysiloxane
gum having a viscosity higher than l million mPa.s at
25°C, and
- (B): 5 to 130 parts by weight of a reinforcing
siliceous filler (B1) chosen from pyrogenic silicas and

66
silicas produced by precipitation.
9. The composition according to one of
claims 6 to 8, wherein the gum (A) has the general
formula R3-a(R'O)aSiO(R2SiO)nSi(OR')aR3a, in which the
symbols R, which may be identical or different,
represent C1-C8 hydrocarbon radicals, which are
unsubstituted or substituted by halogen atoms or cyano
radicals; the symbol R' represents a hydrogen atom or a
C1-C4 alkyl radical, the symbol a represents zero or
one, the symbol n represents a number having a value
sufficient to obtain a viscosity of at least 1 million
mPa.s at 25°C, and at least 50 % by number of the
radicals represented by R are methyl radicals.
10. The composition according to claim 9,
wherein preferably 0.005 to 0.5 mol% of the units
involved in the structure of the gum (A) are chosen
from those of formulae (CH2=CH)(R)SiO and (CH2=CH)R2
a(RO')aSio 0.5.
11. The composition according to one of
claims 6 to 10, wherein it also comprises from 0.1 to
6 parts of a structuring agent (D) which is a fluoro-
organic polymer in tha form of a pulverulent solid.
12. The composition according to one of
claims 6 to 11, wherein it also comprises, in addition
to a reinforcing filler (B1),from 0.1 to 6 parts (B2)
of an organic peroxide.
13. The composition according to claim 12,
wherein up to 90 % by weight of the reinforcing

67
silicone filler (B1) is replaced by semi-reinforcing or
packing fillers.
14. The composition according to one of
claims 6, 12 and 13, cured by heating to form an
elastomer.
15. The composition according to one of
claims 1 to 5, wherein the silicone matrix is a
silicone composition which is vulcanisable at elevated
temperature and comprises (A) a diorganopolysiloxane
gum having, per molecule, at least two vinyl groups
bonded to the silicon and a viscosity at 25°C of at
least 500,000 mPa.s, (B) at least one organo-
hydrogenopolysiloxane having, per molecule, at least
three hydrogen atoms bonded to the silicon, (C) a
reinforcing filler, and (D) a catalytically effective
amount of a catalyst which is a compound of a metal of
the platinum group.
16. The silicone composition according to
claim 15, wherein the compound (C) is a siliceous
reinforcing filler.
17. The composition according to one of
claims 15 and 16, which comprisess
- (A): 100 parts by weight of a diorganopolysiloxane
gum having, per molecule, at least two vinyl groups
bonded to the silicon and a viscosity at 25°C of at
least 500,000 mPa.s,
- (B): at least one organohydrogenopolysiloxane having,
per molecule, at least three hydrogen atoms bonded to

68
the silicon, in an amount such that the ratio by number
of hydride functional groups in (B) to vinyl groups in
(A) is between 0.4 and 10,
- (C): 5 to 130 parts by weight of a reinforcing
filler which is preferably siliceous and is chosen from
pyrogenic silicas and silicas produced by
precipitation, and
- (D): a catalytically effective amount of a catalyst
which is a compound of a metal of the platinum group.
18. The composition according to one of
claims 15 to 17, wherein the gum (A) has the general
formula R3,(R'O),SiO(R2SiO)nSi(OR')aR3a, in which the
symbols R, which may be identical or different,
represent C1-C8 hydrocarbon radicals which are
unsubstituted or substituted by halogen atoms or cyano
radicals; the symbol R' represents a hydrogen atom or a
C1-C4 alkyl radical, the symbol a represents zero or
one, the symbol n represents a number having a Yalue
sufficient to obtain a viscosity of at least 1 million
mPa.s at 25-C, and at least 50 % by number of the
radicals represented by R are methyl radicals.
19. The composition according to claim 18,
wherein preferably 0.005 to 0.5 mol% of the units
involved in the structure of the gum (A) are chosen
from those of formulae (CH2=CH)(R)SiO and
(CH2=CH)R2 a(RO')aSio0.5.
20. The composition according to one of
claims 15 to 19, which comprises from 0.1 to 6 parts of

69
an organohydrogenopolysiloxane (B) having a siloxane
unit of average general formula:
<IMG>
in which R" represents methyl, phenyl and vinyl
radicals, at least 50 % of these radicals being methyl
radicals, c represents any number from 0.01 to 1
inclusive and d represents any number from 0.01 to 2
inclusive.
21. The composition according to any one of
claims 15 to 20, wherein the organohydrogeno-
polysiloxanes are chosen from straight-chain, branched
or cyclic polymers made up of units chosen from those
of formulae:
R"2SiO, H(R")SiO, H(R")2SiO0.5, HSiO1.5, R"SiO1.5SiO2 and
R"SiO0.5 and are added in an amount such that the ratio
by number of hydride.groups in (B) to the vinyl groups
in (A) is between 1.1 and.4.
22. The composition according to any one of
claims 15 to 21, wherein up to 90 % by weight of the
reinforcing siliceous filler (C) is replaced by semi-
reinforcing or packing fillers.
23. The composition according to any one of
claims 15 to 22, which is cured by heating to form an
elastomer.
24. The composition according to any one of
claims 1 to 5, wherein the matrix is a diorgano-
polysiloxane composition curable by polycondenstion

reactions to give a silicone elastomer, which
comprises:
- (A): at least one diorganopolysiloxane oil having at
each end of the chain at least two condensable or
hydrolysable groups or a single hydroxyl group,
- (B): a polycondensation catalyst for the oil, and
- (C): a silane comprising at least three condensable
or hydrolysable groups, when (A) is an oil having
hydroxyl ends.
25. The composition according to claim 24,
wherein the diorganopolysiloxane (A) has the general
formula (1):
YnSi3-n0(SiR20)xSiR3-nYn (1)
in which:
R represents identical or different monovalent
hydrocarbon radicals, Y represents identical or
different hydrolysable or condensable groups, or
hydroxyl groups,
n is chosen from 1, 2 and 3, where n = 1 if Y is a
hydroxyl, and x is an integer higher than 1 and
preferably higher than 10.
26. The composition according to claim 25,
wherein the radical R is chosen from C1-C8 alkyl, vinyl,
phenyl and 3,3,3-trifluoropropyl radicals, at least
60 % by number of the radicals R being methyl radicals.
27. The composition according to one of
claims 25 and 26, wherein Y is chosen from amino,
acylamino, aminoxy, ketiminoxy, iminoxy, enoxy, alkoxy,

71
alkoxyalkyleneoxy, acyloxy and phosphate groups.
28. The composition according to one of
claims 24 to 27, wherein it comprises a silane (D) in
the case where the condensable or hydrolysable groups
are not hydroxyl groups and wherein the silane (D) has
the formula:
R4-aSi Y'a (2)
in which R is a monovalent hydrocarbon radical, Y'
represents identical or different hydrolysable or
condensable groups and a is 3 or 4.
29. The composition according to one of
claims 24 to 28, which is one-component.
30. The composition according to one of
claims 24 to 28, which is two-component.
31. The composition according to claim 30,
which comprises:
- (A): 100 parts by weight of an alpha, omega-
dihydroxydiorganopolysiloxane oil which has a viscosity
of 50 to 300,000 mPa.s and in which the organic
radicals are chosen from methyl, ethyl, vinyl, phenyl
and 3,3,3-trifluoropropyl radicals, at least 60 % by
number being methyl radicals, up to 20 % by number
being phenyl radicals and at most 2 % being vinyl
radicals,
- (B): 0.01 to 1 part (calculated as weight of tin
metal) of a catalytic tin compound,
- (C): 0.5 to 15 parts of a polyalkoxysilane or
polyalkoxysiloxane, and

72
- (D): 0 to 100 parts, preferably 5 to 50 parts, of
siliceous inorganic filler.
32. The composition according to one of
claims 1 to 5, wherein the silicone matrix is a
polyaddition silicone composition which may be cured to
form an elastomer by hydrosilylation reactions, which
comprises:
- (A): at least one organopolysiloxane having, per
molecule, at least two vinyl groups bonded to the
silicon,
- (B): at least one organopolysiloxane having, per
molecule, at least three hydrogen atoms bonded to the
silicon, and
- (C): a catalytically effective amount of a catalyst
which is a compound of a platinum group metal.
33. The composition according to claim 32,
wherein the molar ratio of the hydrogen atoms bonded to
the silicon in (B) to the vinyl radicals bonded to the
silicon in (A) is generally between 0.4 and 10.
34. The composition according to one of
claims 32 and 33, which comprises:
- A) at least one organopolysiloxane having siloxy
units of formula:
<IMG> (1)
in which Y is a vinyl group, Z is a monovalent
hydrocarbon group which does not have an adverse action
on the activity of the catalyst, a is 1 or 2, b is 0, 1

73
or 2 and a + b is between 1 and 3, all of the other
units optionally being units of average formula:
<IMG> (2)
in which Z has the same meaning as above and c has a
value between O and 3.
- B) at least one organopolysiloxane comprising siloxy
units of formula:
<IMG> (3)
in which W has the same definition as above for Z, d is
1 or 2, e is 0, 1 or 2 and d + e has a value between 1
and 3, all of the other units optionally being units of
average formula:
<IMG> (4)
in which W has the same meaning as above and g has a
value between 0 and 3, and
- C) a catalytically effective amount of a platinum
compound.
35. The composition according to one of
claims 32 to 34, which comprises:
- (A): 100 parts of a diorganopolysiloxane oil blocked
at each end of its chain by a vinyldiorganosiloxy unit,
the organic radicals of which, bonded to the silicon

74
atoms, are chosen from methyl, ethyl and phenyl
radicals, at least 60 molar % of these radicals being
methyl radicals, having a viscosity of 100 to
5000,000 mPa.s at 25°C,
- (B): at least one organohydrogenopolysiloxane chosen
from the liquid homopolymers and copolymers which are
straight-chain or have a network structure, which have,
per molecule, at least 3 hydrogen atoms bonded to
different silicon atoms and the organic radicals of
which, bonded to the silicon atoms, are chosen from
methyl and ethyl radicals, at least 60 % of these
radicals being methyl radicals and the product (B)
being used in an amount such that the molar ratio of
the hydride groups to -the vinyl groups is between 1.1
and 4,
- (C)s a catalytically effective amount of a platinum
catalyst.
36. The composition according to claim 35,
wherein 50 % by weight of the polymer (A) is replaced
by a copolymer having a network structure and
comprising the trimethylsiloxy, methylvinylsiloxy and
SiO4/2 units, in which 2.5 to 10 molar % of the silicon
atoms carry a vinyl group and in which the molar ratio
of the trimethylsiloxy groups to the SiO4/2 group is
between a . 5 and 1.
37. The composition according to one of
claims 32 to 36, wherein it also comprises from 5 to
100 parts of reinforcing or semi-reinforcing siliceous

fillers per 100 parts of the sum of the
organopolysiloxanes (A) + (B).
38. The composition according to one of
claims 32 to 37, previously cured to form an elastomer.
39. The composition according to one of
claims 1 to 38, wherein the active substance is a
fungicide.
40. The composition according to one of
claims 1 to 38, wherein the active substance is a
bacteriocide.
41. The composition according to one of
claims 1 to 38, wherein the active substance is an
insecticide.
42. The composition according to one of
claims 1 to 38, wherein the active substance is a
herbicide.
43. The composition according to one of
claims 1 to 38, wherein the active substance is a plant
growth regulator.
44. The composition according to one of
claims 1 to 38, wherein the active substance is a
fertiliser.
45. The composition according to claim 39,
wherein the active substance is aluminium tris-O-
ethylphosphonate.
46. The composition according to one of
claims 1 to 45, wherein the auxiliary agent is a water-
soluble salt.

76
47. The composition according to claim 46,
wherein the auxiliary agent is an inorganic salt.
48. The composition according to claim 47,
wherein the inorganic salt is an alkali metal or
alkaline earth metal salt of a strong inorganic acid.
49. A method for the treatment of plants
with a substance having an agricultural biological
action, characterised by one of claims 1 to 48.
50. The treatment method according to claim
49, wherein the composition is applied against all or
part of the plant for a period sufficient to supply an
effective amount of active substance.
51. The treatment method according to claim
49, wherein the composition is placed in the vicinity
of the plant for a period sufficient to supply an
effective amount of active substance.
52. The treatment method according to claim
51, wherein the composition and the plant or part of
the plant to be treated are in a gaseous medium.
53. The treatment method according to claim
51, wherein the composition and the plant or part of
the plant to be treated are in a humid gaseous
atmosphere.
54. The treatment method according to claim
51, wherein the composition and the plant are in a
divided solid medium, preferably the soil.

Description

- 2036272
Solid silicone compositions havinq an
aqricultural bioloqical action
The present invention relates to solid,
silicone-based compositions having an agricultural
biological action, their preparation and their use for
the treatment of plants.
The treatment of plants and especially of
crops in order ~o promote their growth often requires
the po~sibility of progres~ively salting out the
substances having a biological action from a solid
carr~er onto or towards the plants.
Numerous techniques have been proposed
combining the polymer material and some active
substances, in particular agrochemical or fertiliser
active substances. In fact, these techniques have found
limited practical application or have not found
sufficient outlets because:of ~everal disadvantages, of
which the main di~advantage i3 the difficulty in
controlling the release kinetics of the active
substance and consequently in reliably obtaining a
predetermined effect for a given content of active
substance.
Other dlsadvantages also lie in the fact that
the polymer~ are not sufficiently harmless for the
plants to be treated and for the environment, and also
in their cost and their implementation.
The aim of the present invention is to
alleviate these disadvantages and to provide
'~ ,.

2 2036272
compositions having a progressive biological action
permitting the release of agricultural active
substances in a controlled manner at low cost, and
without disadvantage for the plants to be treated and
for the environment.
More precisely, the invention relates to
solid, polymer-based compositions having an
agricultural biological action in order to promote the
growth of plants, wherein said compositions consist of
a predominant amount of a silicone material, which may
or may not be crosslinked and iB permeable to water
vapour, and a minor amount of an active substance
having an agricultural biological action and a
solubility in water of at least 0.5 g/l, and a water-
soluble auxiliary agent, di3persed homogeneously in thesilicone material, and without an inhibitory effect on
the crosslinking of the silicone, the silicone
material, the water-soluble form of the active
substance and the auxiliary agent being such that the
release kinetics of the active substance by the
silicone matrix are of the order of zero.
The invention relates more particularly to
compositions of the above type wherein the ~ystem
comprising active substance plu8 auxiliary agent is
present in an amount of 5 to 50, preferably 15 to 40,
parts by volume per 100 parts by volume of
organopolysiloxane ~tarting material.
In general, the ratio by volume of the active
.,. . ~: .

3 20362~2
substance to the auxiliary agent may vary from 1~10 to
10/1, preferably from 1/5 to 5/1.
Several groups of silicones may be mentioned
as silicones which can be used as materials in the
compositions according to the invention.
A first ~roup comprises silicone compositions
containing (A) a diorganopolysiloxane gum, (B) a
reinforcing filler (sl), which is preferably siliceous,
and/or an organic peroxide (B2).
Preferred compositions comprise:
- (A): 100 parts by weight of a diorgano-
poly~iloxane gum having a viscosity higher than 1
million mPa.s at 25C, and
- (B): 5 to 130 parts by weight of a
reinforcing siliceous filler (B1) chosen from pyrogenic
silicas and silicas produced by precipitation.
Advantageously, the gum (A) has the general
formula R3,(R'O).SiO(R2SiO)DSi(OR')~R3 " in which the
symbols Rr which may be identical or different,
represent C1-C8 hydrocarbon radicals, which are
unsubstituted or substituted by halogen atoms or cyano
radicals; the symbol R' represents a hydrogen atom or a
C1-C~ alkyl radical, the ~ymbol a re~re~ents zero or
one, the symbol n represents a number having a value
sufficient to obtain a viscosity of at least 1 million
mPa.~ at 25C, and at least 50 % by number of the
radicals represented by R are methyl radicals.
Preferably, O.OOS to 0.5 mol% of the R2SiO

2036272
units involved in the structure of the gum (A) are
chosen from those of formulae (CH2=CH)(R)SiO and
~C~2=CH)R2-a(RO~)asioo~s
The gum (A) ha~ing a viscosity of at least
~. million mPa.s at 25C, and preferably of at least
2 million mPa.s at 25C, is made up, along its chain,
of R2SiO units and is blocked at each end of its chain
by an R3 aR(O)~SiOo 5 unit; however, the presence, in a
mixture with these unit3, of units having a different
structure, for example of formula RSiOlS and SiO2, is
not excluded in a proportion of at most 2 % relative to
the total number of R2SiO and R3~(RO'),SiOos units.
The symbol R repre~ents a ~l-C8 hydrocarbon
radical which i~ unsubstituted or substituted by
halogen atoms or cyano radicals; more specifically, it
encompasYes:
- Cl-C5 alkyl radicala which are un~ubstituted
or substituted by halogen atoms or cyano radicals, such
a~ methyl, ethyl, propyl, i~opropyl, butyl, isobutyl,
pentyl, 3,3,3-trifluoropropyl, beta-cyanoethyl and
gamma-cyanopropyl radical~,
- C2~C~ alkenyl radical~, such as vinyl, allyl
and but-2-enyl radical~, and
- C~-C~ monocyclic aryl radicalR which are
unsubstituted or substituted by halogen atomR, such as
phenyl, chlorophenyl, tolyl and trifluoromethylphenyl
radicals.
The Cl-C~ alkyl radicals represented by the

2~36272
symbol R' relate more specifically to methyl, ethyl,
propyl, isopropyl, butyl and secondary butyl radicals.
At least 50 % by number, and preferably at
least 70 ~, of the radicals represented by R are methyl
radicals.
Moreover, vinyl radicals are preferably also
present, in an appropriate amount, in the gum (A); they
lead to units of formula CH2=CH(R)SiO and
CH2=CH(R2~)(RO~)~SiOo5, the number a of which represents
0.005 to 0.5 mol%, and preferably 0.01 to 0.45 mol%, of
the units of general formulae R2SiO and R3~(RO')~SiOos,
as a whole, which are involved in the structure of the
gum (A)-
Specific examples which may be mentioned of
units making up the gums (A) are those of formulae:
( CH3 ) 2SiO, CH3 ( CH2=CH ) SiO ~ CH3 ( C5H5 ) SiO ~
(C6H,)2SiO, CH3(C2H5)SiO, CH3CH2-CH2(CH3)SiO, CH3(n-
C3H7)SiO, (CH3)3SiOo.5, (cH3)2cH2=cHsioo.5~ CH3(C6H5)2si0.5~ -
CH3(C6H,)(CH2=CH)SiOo.5, HO(cH3)2siOo.5~ CH30(CH3)2si0.5~
2 0 C2H50 ( CH3 ) 2SiO~ 5, n-c3H7o ( CH3 ) 2SiOo 5, HO ( CH2=CH ) ( CH3 ) SiOo 5.
The gums (A) are marketed by silicone
manufacturers and, on the other hand, they may easily
be produced employing techni~ues widely described in
the chemical literature.
In the ma~ority of casQs, methylvinyl-
dimethylpolysiloxane gums having (CH3)2SiO and
CH2=CH(CH3)SiO units along their chain and units chosen
from those of formulae:

2036272
(CH3)2(CH2=CH)SiOo 5, HO(cH3)(cH2=cH)si
(CH3)3siOo.5/ C6H5(CH3) (CH2=cH)sio~ 5~ HO(CH3)2SiOo 5 at the
end of their chain,
or dimethylpolysiloxane gums blocked at each
end of their chain by one of the above units containing
a vinyl radical, are used.
They generally have a viscosity of at least 2
million mPa.s at 25DC.
The fillers (B1), which are preferably
reinforcing silicas, are used in an amount of 5 to 130
parts of the diorganopoiysiloxane gums (A). They are
chosen from silicas produced by combu~tion and silicas
produced by precipitation.
They have a specific surface area, determined
by the BET methods, of at least 50 m2/g and preferably
of more than 70 m2/g, an average size of the primary
particles of les~ than 0.1 ~m (micrometre) and an
apparent density of less than 200 g/litre.
These silicas may be incorporated as such or
after having been treated with organosilicon compound~
customarily used for this application. These compounds
include methylpolysiloxanes, ~uch a~ hexamethyl-
disiloxane and octamethylcyclotetrasiloxane,
methylpolysilazanes, such a~ hexamethyldisilazane and
hexamethylcyclotrisilazane, chlorosilane~, such as
dimethyldichlorosilane, trimethylchlorosilane,
methylvinyldichlorosilane and dimethylvinyl-
chlorosilane, and alkoxysilanes, such as
~ ,

7 2~36272
dLmethyldLmethoxysilane, dLmethylvinylethoxysilane and
trLmethylmethoxysilane.
- During this treatment the silicas may
increase their initial weight by a proportion of up to
20 %, preferably about 18 %.
The compo~itions according to the invention,
that is to say the silicone compositions of the first
group (i.e. A ~ B) mixed with the active substance C,
may be malaxated cold as such and be extruded in very
diverse forms. The silicone composition forms obtained
may be cut to the desired length ~uch that the cut form
contains a sufficient equivalent amount of active
substance for salting out over the desired period.
Surprisingly, it has been discovered that
these non-crosslinked silicone compositions have
adequate physical characteristics for the applications
envi~aged and salt out the active ~ubstance
continuously and in a controlled manner.
Within the framework of the present
invention, an organic peroxide (B2) may be used in
addition to (Bl) or instead of (Bl). It is then
necessary to crosslink the elastomer composition at
elevated temperature.
The organic peroxides (B2) are used in an
amount of 0.1 to 6 parts, prefarably 0.2 to 5 parts,
per 100 parts of the gums (A). They are well known to
those skilled in the art and comprise, more
particularly, benzoyl peroxide, 2,4-dichlorobenzoyl

" 8 2036272
peroxide, dicumyl peroxide, 2,5-bis(t-butylperoxy)-~,5-
dLmethylhexane, t-butyl perbenzoate, t-butyl and
isopropyl peroxycarbonate,-di-t-butyl peroxide and
1,1-bis(t-butylperoxy)-3,3,5-trLmethylcyclohexane.
These various peroxides decompose at
temperatures and at rates which are ~ometLmes
different. They are chosen depending on the curing
conditions required.
The silicone compositions according to the
invention may also comprise, per 100 parts of gum ~A),
from 0.1 to 6 part~ of a structuring agent lD) which is
a fluoro-organic polymer in the form of a pulverulent
solid.
The fluorinated polymers (D) are used in an
15 amount of from U.l to 6 parts, preferably 0.15 to 5
parts, per 100 parts of the diorganopolysiloxane gums
(A). These compound~ are well-known to those-skilled in
the art; they are prepared by polymerisation or
copolymerisation of monomers chosen, for example, from
20 the group comprising tetrafluoroethylene, chlorotri- .
fluoroethylene, vinylidene fluoride and -
hexafluoropropene.
These are, therefore, polymers or copolymers
consisting of units derived from the above monomers;
thus, polytetrafluoroethylenes, binary copolymers of
the polytetrafluoroethylene~beta-fluoropropene type or
of the vinylidene fluoride/hexafluoropropene type, and
ternary copolymers of the vinylidene
:

203~272
fluoride/hexafluoropropene/tetrafluoroethylene type may
be used.
These compounds may be introduced into the
compositions of the invention in the form of powders
having an average particle diameter of less than 100
micrometres, for example having a diameter ranging from
25 to 65 micrometres.
Preferably, when the crosslinking agents (B2)
are used, up to 90 % by weight of the reinforcing
silicas (Bl) may be replaced by semi-reinforcing or
packing fillers, the particle diameter of which is
greater than 0.1 ~m, such as ground quartz, calcined
clays and diatomaceous earths.
The silicone compositions may also comprise
from l to lO parts of dimethylpolysiloxane oil (E)
having silanol ends and having a viscosity at 25C of
between 10 and 5,000 mPa.s, preferably from 30 to 1,000
mPa.s, per 100 parts of gum (A). Their use i~
recommended in particular when the amounts of
reinforcing fillers (Bl) are high.
The preparation of the compositions according
to the invention is effected with the aid of known
mechanical means, for example kneaders, cylinder mixers
or ~crew mixers.
The various constituents are incorporated in
this equipment in a sequence which may be arbitrary.
However, it is recommended to charge the gum (A), then,
in sequence, the siliceous fillers (Bl) and the active

2036272
substance (C), where appropriate the additive (E) and,
finally, the compound (D) and (Bz).
The compositions o~tained are stable on
storage; moreover, they mould and extrude easily, which
allows very varied forms to be produced. Those
compositions which contain peroxide (B2) are crosslinked
by heating. The heating time obviously varies with the
temperature, the pressure and the nature of the
crosslinking agents. It i~ generally of the order of
several minutes at about 150-250C and a few seconds at
about 250-350C.
The ela~tomers thu~ formed may sub~equently
be post-heated if nece~sary, especially those obtained
by moulding for a period of at least one hour at a
temperature of between 190 and 270C, with the aim of
completing their crosslinking.
However, from the end of their first
crosslinking stage, that is to say before any post-
heating stage, these ela~tomers have physical
characteristics ade~uate for the envisaged application.
The optionally crosfilinked silicone
compositions are advantageou~ly in varied solid forms.
The amount of active substance and the salting out
period are determined for a given presentation.
A second ~roup of silicones which may be used
according to the invention comprises vulcani~able, and
preferably hot-vulcanisable, silicone compositions
containing:

11 2036272
(A) a diorganopolysilo~;ane gum having, per
molecule, at least two vinyl groups bondPd to the
silicon and a viscosity at 25DC of at least 500,000
mPa.s,
(B) at least one organohydrogenopolysiloxane
having, per molecule, at least three hydrogen atoms
bonded to the silicon,
(C) a reinforcing filler, and
(D) a catalytically effective amount of a
catalyst which is a compound of a metal of the platinum
group.
More precisely, the pre~ent invention relates
to a silicone composition compri~ing:
- (A): 100 parts of a diorganopolysiloxane
gum having, per molecule, at least two vinyl groups
bonded to the ~ilicon and a visco~ity at 25-C of at
least 500,000 mPa.s,
- (B): at least one organohydrogeno-
polysiloxane having, per molecule, at least 3 hydrogen
atoms bonded to the silicon, in an amount such that the
ratio by number of hydride functional groups in (B) to
vinyl groups in (A) is between G.4 and 10,
- (C): 5 to 130 parts of a reinforcing
filler which is preferably siliceous and is chosen from
25 pyrogenic silica~ and silicas produced by
precipitation, and
- (D): a catalytically effective amount of a
catalyst which is a compound of a metal of the platinum
. ..~

12 203 62 72
group.
The ratio by number of hydride groups in (B)
to vinyl groups in (A) may be very variable. It is
generally between 0.4 and 10, preferably between 1.1
and 4.
More particularly, the diorganopolysiloxane
gum (A) has the general formula
R3 ~(R'O)~SiO(R2SiO)nSi(OR' )~R3 ~, in which the symbols R,
which may be identical or different, represent C1-C~
hydrocarbon radicals which are unsubstituted or
substituted by halogen atoms or cyano radicals; the
symbol R' represents a hydrogen atom or a Cl-C~ alkyl
radical, the symbol a represent~ zero or one, tha
symbol n represents a number having a value sufficient
to obtain a viscosity of at least 500,000 mPa.s at
25C, and at least 50 % by number of the radicals
represented by R are methyl radicals.
Preferably, 0.005 to 0.5 mol% of the units
involved in the ~tructure of the gum (A) are chosen
from those of formulae ~CH2=CH)(R)SiO and/or
( CH2=CH ) RZ . ( RO ' ) ~si0.5 -
The gum (A) having a viscosity of at least
500,000 mPa.~ at 25C and preferably of at least 1
million mPa.s at 25-C is made up of RzSiO units along
its chain and it is blocked at each end of its chain by
an R3,R(O),SiOo 5 unit; however, the presence, in a
mixture with these units, of units of different
structure, for example of formula RSiO~ 5 and SiO2, is
~ ,
:

13 2~3~272
not excluded in a proportion of at most 2 ~ relative to
the total number of R2SiO and R3a(RO )aSiO05 units.
The symbol R represents a Cl-C8 hydrocarbon
radical which is unsubstituted or substituted by
halogen atoms or cyano radicals; more specifically, it
encompasses:
- Cl-C5 alkyl radicals which are unsubstituted
or substituted by halogen atoms or cyano radi~als, quch
as methyl, ethyl, propyl, isopropyl, butyl, i~obutyl,
pentyl, 3,3,3-trifluoropropyl, beta-cyanoethyl and
gamma-cyanopropyl radical~,
- C2-C~ alkenyl radicals, such as vinyl, allyl
and but-2-enyl radicals, and
- C6-C~ monocyclic aryl radicals which are
unsubstituted or substituted by halogen atoms, such as
phenyl, chlorophenyl, tolyl and trifluoromethylphenyl
radicals.
The Cl-C~ alkyl radical~ repre~ented by the
symbol R~ relate more ~pecifically to methyl, ethyl,
propyl, isopropyl, butyl and secondary butyl radicals.
At least 50 % by number and preferably at
lea~t 70 ~ of the radical~ R are methyl radicals.
Moreover, -~inyl radical~ are preferably al~o
preqent, in an appropriate amout, in the gum ~A); they
lead to units of formula CH2=CH(R~SiO and
CH2=CH(R2~)(RO')~SiOos, the number of which represents
O.OOS to O.S mol%, preferably 0.01 to 0.45 mol~ of the
units of general formulae R2SiO and R3,(RO')~SiOo5 a~ a

14 2036272
whole which are involved in the structure of the gum
~A).
- Specific examples which may be mentioned of
units making up the gums (A) are those of formulae:
(CH3)2SiO, CH3(CH2=CH)SiO, C~3(C~Hs)si~
(C6H5)2SiO, CH3tc2H5)sio, CH3CH2-CH2(CH3)SiO, CH3(n-
C3H7)5iO, (CH3)3SiOo.5, (cH3)2(cH2=cH)siOo5~ CH3(C6~s)2siosr
CH3(C6H5) (CH2=CH)SiOo.5, Ho(cH3)2sioo.5~ CH3(CH3~2sia.s~
C2Hs(cH3)2si0.5~ n-C~H70(CH3)2SiOO5 and
HO(CH2=CH)(CH3)SiOo.s-
The gum~ (A) are marketed by silicone
manufacturer~ and, on the other hand, they may easily
be produced employing techniques widely described in
the chemical literature.
In the ma~ority of cases, methylvinyl-
dimethylpolysiloxane gums having ICH3)2SiO and
CH2-CH(CH3)SiO units along their chain and unit~ chosen
from those of formulae:
(CH3)2(CH2=CH)SiOo.5~ HO(CH3)(cH2=cH)si
(CH3)3SiOo 5, C~H5(CH3)(CH2=CH)SiOo5 and HO(CH3)2SiOo 5
at the end of their chain, or dimethyl-
polysiloxane gums blocked at each end of their chain by
one of the above units containing a vinyl radical, are
used.
They generally have a visc03ity of at least
2 million mPa.s at 25~C.
The organohydrogenopolysiloxane (B) has a
siloxane unit of average general formulas
'

203627~
(H~c (R )dSiO5-d-c
in which R~ represents methyl, phenyl and
vinyl radicals, at least 50 % of these radicals being
methyl radicals, c represents any number from 0.01 to 1
:inclusi~e and d represents any number from 0.01 to 2
inclusive.
These organohydrogenopolysiloxanes (B) are
chosen from straight-chain, branched or cyclic polymerY
made up of units chosen from those of formulae:
R"2SiO, ~(R")SiO, H(R" )2sioo 5~ HSiOl 5,
R~SiO~5SiO2 and RNSiOo 5.
They may be liquid, gum-like or resinous.
They contain at least 3SiH per molecule.
Specific examples of products (B) widely
mentioned in the literature are described in detail in
US Patents US-A-3 220 972, US-A-3 284 406,
US-A-3 436 366 and US-A-3 697 473, which are cited as
reference~.
The filler~ (C), which ara preferably
reinforcing silicas, are u~ed in an amount of 5 to 130
parts of the diorganopolysiloxane gum~ (A). They are
chosen from ailicas produced by combustion and silicas
produced by precipitation. ~hey have a specific ~urface
area, determined by the BET methods, of at least 50 m2~g
and preferably more than 70 m2/g, an average size of the
primary particles of less than 0.1 ~m (micrometres) and
an apparent density of les~ than 200 g/litre.

16 2036272
These silicas may be incorporated as such or
after having been treated with organosilicon compounds
customarily used for this application. These compounds
imclude methylpolysiloxanes, such as hexamethyl-
S disiloxane and octamethylcyclotetrasiloxane, methyl-
polysilazanes, such as hexamethyldisilazane and hexa-
methylcyclotrisilazane, chlorosilanes, such as
dLmethyldichlorosilane, trLmethylchlorosilane,
methylvinyldichlorosilane and dimethylvinyl-
chlorosilane, and alkoxysilanes, such as dLmethyl-
~ ethoxy~ilane, dimethylvinylethoxysilane and
trimethylmethoxysilane.
During this treatment the silicas-may
increase their initial weight by a proportion of up to
20 %, preferably about 18 %.
It i~ desirable to add a catalytically
effective amount of a hydrosilylation catalyst (D),
which is a platinum group compound, preferably
platinum, in an amount of 0.001 to 1 %, preferably of
0.05 to 0.5 %, calculated as weight of catalytic metal
relative to the weight of the gum (A) and of the
organo-hydrogenopolysiloxane (B).
All of the platinum compounds widely
described in the literature as hydrosilylatlon
catalysts may be used, in particular chloroplatinic
acid H2PtCl6, the reaction product~ of chloroplatinic
acid with alcohols, ethers or aldehydes (US Patent
US-A-3 220 972) and the reaction products of

17 203627~
chloroplatinic acid with vinylpolysiloxanes, which may
be untreated or treated with an alkaline agent in order
at least partially to remove the chlorine atoms (US
Patents US-A-3 419 593, US-A-3 775 452 and
US-A-3 814 730).
Up to 90 % by weight of the reinforcing
silicas (C) may be replaced by semi-reinforcing or
packing fillers, the particle diameter of which is
greater than 0.1 ~m (micrometre), such as ground
~uartz, calcined clays and diatomaceous earths.
The silicone compositions may also comprise
from 1 to 10 part~ of dimethylpolysiloxane oil~ (F)
having silanol ends and a viscosity at 25C of between
10 and 5,000 mPa.s, preferably from 30 to 1,000 mPa.s,
per 100 parts of gum (A). Their use is recommended in
particular when the amounts of reinforcing fillers (C)
are high.
The preparation of the compositions according
to the invention i8 effected with the aid of known
mechanical means, for example kneader3, cylinder mixers
or ~crew mixers.
The various constituents are incorporated in
thi~ equipment in a sequence which may be arbitrary.
However, it i~ recommended to charge the gum (A), than,
in sequence, the siliceous fillers (C) and the active
substance (E), where appropriate the additive (F) and,
finally, the compound (D). If the composition must be
stored before its extrusion and/or moulding, it is
:`
,

18 2036272
desirable to add an effective amount of an agent which
inhibits the catalytic action of platinum and
disappears at elevated temperature during the
vulcanisation of the composition. Thus, inhibitors
which may be used are, in particular, organic amines,
silazanes, organic oxLmes, diesters of carboxylic
diacids, acetylenic ketones and vinylmethylcyclopoly-
siloxanes ~see in particular US-A-3 445 420 and
US-A-3 989 667).
The inhibitor is used in an amount of from
0.005 to 5 parts, preferably 0.01 to 3 parts, per 100
parts of constituent (A).
The compositions obtained mould and extrude
easily, which allows very varied forms to be produced.
~he can also be cured to give elastomers by heating
under pressure or in amb1ent air at temperatures of the
order of 100 to 350C.
The heating time o~viously varies with the
temperature, the pressure and the nature of the
crosslinking agents. It i~ generally of the order of
several minutes at about 150-250-C and of a few seconds
at about 250-350C.
The elastomers thus formed may, if
appropriate, subsequently be post-heated, especially
those obtained by moulding for a period of at least one
hour at a temperature of between 190 and 270C with the
aim of completing their crosslinking.
However, from the end of their first

19 2036272
crosslinking stage, that is to say before any post-
heating stage, these elastomers have physical
characteristics adequate for the envisaged application.
Thus, the compositions according to the
invention may be malaxated cold as such and be extruded
and/or moulded and then vulcanised into very varied
shape~.
A ~hird arouD of silicones which may be used
according to the invention comprise~ diorganopoly-
siloxane compositions which may be cured to give asilicone elastomer by polycondensation reactions,
comprising:
- (A): at least one diorganopolysiloxane oil
having at each end of the chain at lea~t two
condensable or hydrolysable groups or a single hydroxyl
group,
- (B): a polycondensation catalyst for the
oil, and
- (C): a silane comprising at least three
condensable or hydrolysable groups, when (A) i8 an oil
having hydroxyl ends.
In the following and the foregoing text,
unles~ indicated to the contrary, percentages and parts
are by weight.
The diorganopolysiloxane oils (A) which may
be used in the compo~itions according to the invention
are more particularly those of formula (1):
YDS i3_DO ( SiR2 ) ~SiR3 DYD ( 1 )

o 2036272
in which:
R represents identical or different
monovalent hydrocarbon radicals, Y represents identical
or different hydrolysable or condensable groups, or
hydroxyl groups,
n is chosen from 1, 2 and 3, where n = 1 if Y
i5 a hydroxyl, and x is an integer higher than 1 and
preferably higher than 10.
The viscosity of the oils of formula (1) is
between 50 and lo6 mPa.s at 25C. The following may be
mentioned as example~ of radical~ R: alkyl radic ls
having from 1 to 8 carbon atoms, such a~ methyl, ethyl,
propy~, butyl, hexyl and octyl, vinyl radicals and
phenyl radicals.
The following may be mentioned as examples of
substituted radical~ Rs 3,3,3-trifluoropropyl,
chlorophenyl and beta-cyanoethyl radicals.
In the products of formula (1) which are
generally used industrially, at least 60 % by number of
the radicals R are methyl radicals, the other radicals
generally being phenyl and/or vinyl radicals.
The following may be mentioned as examples of
hydrolysablo groups Y: amino, acylamino, aminoxy,
ketiminoxy, iminoxy, enoxy, alkoxy, alkoxy-alkyleneoxy,
acyloxy and phosphato groups.
The following may be mentioned as examples of
amino groups Y: n-butylamino, sec-butylamino and
cyclohexylamino groups; as examples of N-substituted
.
.

21 203~272
acylamino groups: the benzoylamino group; as examples
of aminoxy groups: dimethylaminoxy, diethylaminoxy,
dioctylaminoxy and diphenylaminoxy groups; as examples
of Lminoxy and ketLminoxy groups Y: those derived from
S acetophenone oxime, acetone oxLme, benzophenone oxLme,
methyl ethyl ketoxime, diisopropyl ketoxLme and
chlorocyclohexanone oxLme.
Alkoxy groups Y which may be mentioned are
the groups having from 1 to 8 carbon atoms, such as the
methoxy, propoxy, isopropoxy, butoxy, hexyloxy and
octyloxy groups, and an alkoxy-alkyleneoxy group Y
which may be mentioned is the methoxy-ethyleneoxy
group.
Acyloxy groups Y which may be mentioned are
the groups having from 1 to 8 carbon atoms, such as the
formyloxy, acetoxy, propionyloxy and 2-ethylhexanoyloxy
groups.
Phosphato groups Y which may be mentioned are
those which are derived from dimethyl phosphate,
diethyl phosphate and dibutyl phosphate groups.
Condansable groups Y which may be mentioned
are the hydrogen atoms and the halogen atoms,
preferably chlorine.
When, in the above formula (1), the groups Y
are hydroxyl groups and n is then egual to 1, it is
necessary, in order to prepare the polyorganosiloxane
elastomers from the polymers of formula (1) above, to
use, in addition to the condensation catalysts,

22 2~3~27~
crosslinking agents (D) which have already been
indicated and which are silanes of general formula:
R4~Si Y'~ (2)
in which:
R has the meanings given above for formula
(1) and Y' represents identical or different
hydrolysable or condensable groups, and a is 3 or 4.
The examples given for the ~roups Y are
applicable to the groups Y'.
It is desirable to use silanes of formula (2)
e~en in the case where ~ in the oil (A) is not a
hydroxyl group.
In this case it is desirable to use groups Y
in the oil ~A) which are identical to the Y' in the
silane (D).
The alpha, omeya-dihydroxy-diorganopoly-
siloxanes of formula (1) are generally oils, the
vi~cosity of which varies from 500 mPa.s at 25C to
500,000 mPa.s at 25DC, preferably 800 mPa.s to 400,000
at 25C, that is ~traight-chain polymers essentially
consisting of diorganosiloxy units of formula (R2SiO).
Howe~er, tha presence of other units,
generally present as impurities, such a~ R SiO3/2,
R SiO"2 and S~O~2, is not excluded in a proportion of at
most 1 % relative to the number of diorganosiloxy
units.
The organic radicals, which are bonded to the
~ilicon atoms of the base oils and are represented by

203627~
23
the symbol R, may be chosen from alkyl radicals having
from 1 to 3 carbon atoms, such as the methyl, ethyl and
n-propyl radicals, the vinyl radical, the phenyl
radical, the 3,3,3-trifluoropropyl radical and the
beta-cyanoethyl radical.
At least 60 ~ of all of the radicals R are
methyl radicals; at most 1 % are vinyl radicals.
By way of illustration of units represented
by the formula RzSiO, those of the following formulae
may be mentioned:
(CH3)ZSiO; CH3(CHZ=CH)SiO; CH3(C8,H5)SiO;
CF3CH2CH2 ( CH3 ) SiO; NC-CH2CH2 ( CH3 ) SiO; NC-CH2 ( C6H5 ) SiO .
The great majority of these base oils are
marketed by silicone manufacturers. On the other hand,
lS their production techniques are well known and are
found described, for example, in French Patents
FR-A-1 134 005, FR-A-1 198 749 and FR-A-l 226 745.
The following may be mentioned more
particularly as examples of ~ilane monomers (D) of
formula (2): polyacyloxysilanes, polyalkoxysilanes,
polyketiminoxy~ilane~ and polyiminDxysilanes, and in
particular the following 6ilanes:
' CH3Si(OCOCH3)3; C2H5Si(OCOC~3)3;
(CH2 = CH)Si(OCOCH3)3; C5H,Si(OCOCH3)3;
CF3CH2CH2Si(OCOCH3)3; NC-CH2CH2Si(OCOCH3)3;
CH2ClSi(OCOCH2CH3)3; CH3Si(ON=C(CH3)C2H5)2OCH2CH2OCH3 and
CH3Si(ON=CH-CH3)zOCH2CH2OCH3.
The above silanes (D) in combination with the
:

24 2~3~272
alpha, omega-dihydroxy-polydiorganosiloxanes of formula
~1) may be used in one-component compositions which are
~table in the absence of air.
Examples which may be mentioned of silane
monomers of formula (2) which, in combination with
alpha, omega-dihydroxy-polydiorganosiloxanes of formula
(1), may advantageously be used in two-component
compositions are polyalkoxysilanes and in particular
those of formulae:
Si(OC2H5)4; Si(O-n-C3H~)~; Si(O-isoc3H7)~;
Si ~ OC2H"OCH3 ) ~; CH3Si ( OCH3 ) 3; CH2=CHSi ~ OCH3 ) 3;
CH3Si ( OC2H"OCH3 ) 3; ClCH2S i ( OC2Hs ) 3; CH2 = CHSi ( OCzH40CH3 ) 3 .
All or part of the silane monomer~ described
above may be replaced by polyalkoxypolysiloxanes, each
molecule of which carries at least two and preferably
three atoms Y'; the other silicon valencies are
satisfied by the siloxPne bonds.SiO and SiR.
An example which may be mentioned of a
polymer crosslinking agent i~ ethyl polysilicate.
Generally from 0.1 to 20 parts by weight of
crosslinking agent of formula (2) are u~ed per 100
parts by weight of polymer of formula (1).
The ~olyorganosiloxane compositions which are
curable to an elastomer of the type described above
comprise from 0.001 to 10 parts by weight, preferably
from 0.05 to 3 parts by weight, of condensation
catalyst (C) per 100 parts by weight of polysiloxane of
formula (1).

2036272
The condensation catalyst content in the one-
component compositions is generally very much lower
than that used in the two-component compositions and is
generally between 0.001 and 0.05 parts by weight per
100 parts by weight of polysiloxane of formula (2).
The crosslinking agents (D) of formula (2),
which may be used to prepare either one-component or
two-component compositions, are products available on
the silicone market; moreover, their use in
compositions which cure from ambient temperature is
known: they are cited in particular in French Patents
FR-A-l 126 411, FR-A-l 179 969, FR-A-l 189 216,
PR-A-l 198 749, FR-A-l 248 826, FR-A-l 314 649,
FR-A-l 423 477, PR-A-l 432 799 and FR-A-2 067 636.
The compositions according to the in~ention
may al~o comprise reinforcing or ~emi-reinforcinq or
packing fillers (E), which are preferably chosen from
the siliceous fillers, silica~ produced by combustion
and ~ilicas produced by precipitation.
They have a specific surface area, determined
by the BET methods, of at least 50 m2/g and preferably
more than 70 m2~g, an average size of the primary
particles of less than 0.1 ~m (micrometre) and an
apparent density of less than 200 g/litre.
These silicas may be incorporated as such or
after having been treated with the organosilicon
compounds customarily used for this application. These
compounds include methylpolysiloxanes, such as
':

26 20~27~
hexamethyldisiloxane and octamethylcyclotetrasiloxane,
methylpolysilazanes, such as hexamethyldisilazane and
hexamethylcyclotrisilazane, chlorosilanes, such as
dimethyldichlorosilane, trimethylchlorosilane,
S methylvinyldichlorosilane and dLmethylvinyl-
chlorosilane, and alkoxysilanes, such as dLmethyldi-
methoxysilane, dimethylvinylethoxysilane and trimethyl-
methoxysilane.
During this treatment the silicas may
i~ se their initial weight by a proportion of up to
20 %, preferably about 18 %.
The semi-reinforcing or packing fillers have
a particle diameter greater than O . l ~m (micrometre)
and are chosen from ground quartz, calcined clays and
diatomaceous earths.
In general from 0 to 100 parts, preferably
from 5 to 50 parts, of filler (E) may be used per 100
parts of oil (A).
The bases of siiicone composition~ generally
defined above are well known to those skilled in the
art. They are described in detail in the literature, in
particular in numerou~ patents, and the ma~ority are
a~railable commercially.
These compositions cros~link at ambient
temperature in the presence of moisture supplied by
atmospheric humidity and/or contained in the
composition. They are subdivided into two large groups.
The first group is made up of the one-component
. ~ ' ' .

27 2036272
composi~ions, or compositions in a single packaging,
which are stable on storage in the absence of
atmospheric humidity and crosslink to form an elastomer
in the presence of atmospheric humidity. In this case,
the condensation catalyst (C) used is a metal compound,
generall~ a tin, titanium or zirconium compound.
Depending on the nature of the condensable or
hydrolysable groups, these one-component compositions
are termed acid, neutral or basic.
Acid compositions which may be mentioned are,
for examplç ? the compositions described in the patents
US-A-3 035 016, US-A-3 077 465, US-A-3 133 891,
US-A-3 409 573, US-A-3 438 g30, US-A-3 647 917 and
US-A-3 886 118.
Neutral compositions which may be used are,
for example, the compositions described in the patents
US-A-3 065 194, US-A-3 542 901, US-A-3 689 454,
US-A-3 779 986, GB-A-2 052 540, US-A-4 417 042 and
EP-A-69 256.
Basic compositions which may be used are, for
example, the compositions described in the patent~
US-A-3 378 520, US-A-3 364 160, US-A-3 417 047,
US-A-3 i64 951, US-A-3 742 004 and US-A-3 758 441.
According to a preferred variant, it is also
po~sible to use the free-flowing one-component
compositions such as those described in the patents
US-A-3 922 246, US-A-3 956 280 and US-A-4 143 088.
The second group, which is the preferred

2036272
28
group within the framework of the present invention, is
made up of the two-component compositions, or
compositions contained in two packagings, generally
comprising an alpha, omega-dihydroxydiorganopoly-
siloxane oil (A), a silane (D) or a product resultingfrom the partial hydrolysis of this 6ilane, and a
catalyst (C), which is a metal compound, preferably a
tin compound, and~or an amine.
Examples of such compo~itions are described
in the patents US-A-3 678 002, US-A-3 888 815,
US-A-3 933 729, US-A-4 064 096 and GB-A-2 032 936.
Amongst these compositions, those preferred
more particularly are the two-component compositions
comprising:
- ~A): 100 part~ of an alpha, omega-
dihydroxydiorgsnopolysiloxane oil which has a vi~osity
of 50 to 300,000 mPa.s and in which the organic
radicals are chosen from..methyl, ethyl, vinyl, phenyl
and 3,3,3-trifluoropropyl radical~, at least 60 ~ by
number being methyl radical~, up to 20 ~ by number
being phenyl radicals and at most 2 % being vinyl
radicals,
(C)s 0.01 to 1 part (calculated as weight
of tin metal) of a catalytic tin compound,
- (D): 0.5 to 15 parts of a polyalkoxysilane
or polyalkoxysiloxane, and
- (E): 0 to 100 parts, preferably 5 to 50
parts, of siliceous inorganic filler.
~. ~

2036272
The tin catalysts (C) are widely described in
the above literature and this catalyst may be, in
particular, a tin salt of a monocarboxylic or
dicarboxylic acid. These tin carboxylates are described
in particular in the publication by NOLL (Chemistry and
Technology of Silicones, page 337, Academic Press,
1968, 2nd edition).
Dibutyltin naphthenate, octanoate, oleate,
butyrate and dilaurate and dibutyltin diacetate may be
mentioned in particular.
The catalytic tin compound used may also be
the product of the reaction of a tin salt, in
particular of a tin dicarboxylate, with an ethyl
polysilicate as described in the patent US-A-3 186 963.
It is also possible to use the product of the reaction
of a dialkyldialkoxysilane with a tin carboxylate as
de~cribçd in the patent US-A-3 862 919.
It is also possible to use the product of the
reaction of an alkyl silicate or of an alkyltri-
alkoxysilane with dibutyltin diacetate as described inBelgian Patent B~-A-824 305.
Amongst the cros~linking agents (D), those
more particularly preferred are alkyltrialkoxysilanes,
alkyl ~ilicate~ and alkyl polysilicates, in which the
organic radicals are alkyl radicals having from 1 to 4
carbon atoms.
The alkyl silicates may be chosen from methyl
silicate, ethyl silicate, isopropyl silicate and

203~272
n-propyl silicate, and the polysilicates chosen from
the partial hydrolysis products of these silicates;
these are polymers consisting of a significant
proportion of units of formula ~R40~3Sioo 5r R40Sio~ 5,
S (R40)2Sio and SiO2; the symbol R4 representing methyl,
ethyl, isopropyl and n-propyl radicals. The
characterisation of these compounds is customarily
based on their silica content, which is established by
determination of the hydrolysis product of a sample.
In particular, the polysilicate used may be a
partially hydrolysed ethyl silicate marketed under the
name "Ethyl Silicate-40"R by Union Carbide Corporation,
or a partially hydrolysed propyl silicate.
The compositions according to the invention
may be shaped, extruded or, in particular, moulded into
varied forms and then cured at ambient temperatu~e to
give an elastomer under atmospheric humidity or by the
addition of water. Slight heating to a temperature of
20 to 150C may accelerate curing.
Surpri~ingly, it has been discovered that
these crosslinked silicone compositions have phy~ical
characteri~tics adequate for the applications
envisaged.
A fourth arou~ of silicones which may be used
according to the invention in effect relates to a
polyaddition silicone composition which may be cured to
form an ela~tomer by hydrosilylation reactions, which
comprises:

- 203g27~
31
- ~A): at least one organopolysiloxane
having, per molecule, at least two vinyl groups bonded
to the silicon,
- (B): at least one organopolysiloxane
having, per molecule, at least three hydrogen atoms
bonded to the silicon, and
- ~C): a catalytically effective amount of a
catalyst which is a compound of a platinum group metal~
In the followinq and foregoing text, unles~
indicated to the contrary, percentages and parts are by
weight.
The amounts of (A) and (B) are generally
chosen such that the molar ratio of the hydrogen atoms
bonded to the silicon in (B) to the vinyl radicals
bonded to the silicon in ~A) i5 generally between 0.4
and 10 and preferably between 0.6 and 5.
The vinyl group~ in (A) and the hydrogen
atoms in (B) are generally bonded to different silicon
atoms.
These compositions crosslink by an addition
.reaction (also termed hydrosilylation reaction),
cataly~ed by a compound of a platinum group metal, of a
vinyl group in the organopolysiloxane (A) with a
hydride group of the organopolysiloxane (D).
The vinyl-containing organopoly~iloxane (1)
may be an organopolysiloxane having siloxy units of
formula:
"'`' :~

32 2036272
Yl. Zb S iO( ~ b ) ( 1 )
in which Y is a vinyl group and Z is a
monovalent hydrocarbon group which does not have an
adverse action on the activity of the catalyst. Z is
generally chosen from alkyl groups having from 1 to 8
carbon atoms inclusive, such as methyl, ethyl, propyl
and 3,3,3-trifluoropropyl groups, and aryl groups, such
as xylyl, tolyl and phenyl, a is 1 or 2, b is 0, 1 or 2
and a + b is between 1 and 3, all of the other units
optionally being units of average formula:
ZcSiO~-c (2)
in which Z has the same meaning as above and
c has a value between 0 and 3.
The organopolysiloxane (B) may be an
organohydrogenopolysiloxane comprising siloxy units of
formula:
HdW.SiO~ -d--
(3)
in which W is a monovalent hydrocarbon group
which does not have an adverse action on the activity
of the catalyst and has the same definition as Z, d is
1 or 2, e is 0, 1 or 2 and d + e has a value between 1
and 3, all of the other units optionally being units of
average formula:

- 33 2036272
w~SiO~-~ (4
in which W has the same meaning as above and
g has a value between 0 and 3.
All of the lLmiting values-for a, b, c, d and
g are inclusive.
The organopolysiloxane (A) may be formed
solely of units of formula (1) or may also contain
units of formula (2).
The organopolysiloxane (A) may have a
straight-chain, branched, cyclic or network structure.
The degree of polymerisation is 2 or more and is
generally below 5,000. Moreover, if the
organopoly~iloxane (A) i8 straight-chain, it ha~ a
viscosity at 25C of less than 500,000 mPa.s.
Z i~-generally chosen from methyl, ethyl and
phenyl radicals, at least 60 molar % of the radicals Z
being methyl radicals.
The organopolysiloxanes (A) and (B) are well
known and are described, for example, in the patents
US-A-3 220 972, US-A-3 284 406, US-A-3 436 366,
US-A-3 697 473 and US-A-4 340 709.
Examples of siloxy units of formula (1) are
the vinyldimethylsiloxy unit, the vinylphenylmethyl-
siloxy unit, the vinylsiloxy unit and the vinylmethyl-
25 siloxy unit.
Examples of siloxy units of formula (2) are
.~ . . .
,
. . .
.~
. ..

2036272
the SiO4~2, dLmethylsiloxane, methylphenylsiloxane,
diphenylsiloxane, methylsiloxane and phenylsiloxane
u~its.
Examples of organopolysiloxane (A) are the
dimethylpolysiloxanes having dimethylvinylsiloxy ends,
the methylvinyldimethylpolysiloxane copolymers having
trimethylsiloxy ends, the methylvinyldimethylpoly-
siloxane copolymers having dimethylvinylsiloxy ends and
the cyclic methylvinylpolysiloxanes.
The organopolysiloxane (B) may be formed
solely of units of formula (3) or additionally contains
units of formula (4).
The organopolysiloxane (B) may have a
straight-chain, branched, cyclic or network structure.
The degree of polymerisation is 2 or more and is
generally below 5,000.
The group W has the same meaning as the group
Z above.
Examples of unit~ of formula (3) are:
H(CH3)2SiOlt2, HCH3SiO2~2, H(C0Hs)si2~2-
The examples of units of formula (4) are the
same a~ those given above for the units of formula ~2).
Example~ of organopolysiloxane (B) ares
- the dimethylpolysiloxanes having
hydrogenodimethylsilyl end~, the dimethylhydrogeno-
methylpoly~iloxane copolymer~ having trimethylsiloxy
ends, the dimethylhydrogenomethylpolysiloxane
copolymers having hydrogenodimethylsiloxy ends, the

2036272
hydrogenomethylpolysiloxanes having trLmethylsiloxy
ends and the cyclic methylvinylpolysiloxanes.
- The ratio of the number of hydrogen atoms
bonded to the silicon in the organopolysiloxane (B) to
the number of groups having an alkenyl unsaturation in
the organopolysiloxane (A) is between 0.4 and 10,
preferably between 0.6 and 5. This ratio may, however,
be between 2 and 5 if it is desired to make elastomer
foams.
The organopolysiloxane (A) and/or the
organopolysiloxane (2) may be diluted in a non-toxic
organic solvent compatible with silicones.
The organopolysiloxanes (A) and (B) having a
network ~tructure are commonly ~ermed silicone resins.
The bases of polyaddition silicone
compositions may comprise only straight-chain
organopolysiloxanes tl) and (2), such as, for example,
those described in the abovementioned US patents:
US-A-3 220 972, US-A-3 697 473 and US-A-4 340 709, or
simultaneously comprise organopolysiloxanes (A) and (B)
which are branched or have a network structure, such
as, for example, those described in the abovementioned
US paterts: US-A-3 284 406 and US-A-3 436 366.
The catalysts (C) are also well known.
Platinum and rhodium compounds are preferably
used.
In particular, it is possible to use the
complexes of platinum and an organic product described
.

2036272
36
in the US patents US-A-3 159 601, US-A-3 159 602,
US-A-3 220 972 and the European patents EP-A-57 459,
EP-A- I88 978 and EP-A- l 90 530, or the complexes of
platinum and vinyl-containing organopolysiloxane
described in the US patents: US-A-3 419 593,
US-A-3 715 334, US-A-3 377 432 and US-A-3 814 730.
In particular, it is possible to u~e the
rhodium complexes described in the British patents:
GB-A-l 421 136 and GB-A-l 419 769.
The generally preferred catalyst is platinum.
In this case the amount by weight of catalyst
(C), calculated as weight of platinum metal, is
generally between 2 and 600 ppm, in general between 5
and 200 ppm, based on the total weight of the
organopolysiloxanes (A) and (B).
The preferred co~po~itions within the
framework of the present invention are those which
comprise:
- (A): 100 parts of a diorganopolysiloxane
oil blocked at each end of its chain by a vinyldi-
organosiloxy unit, the organic radicals of which,
bonded to the silicon atoms, are chosen from methyl,
ethyl and phenyl radicals, at least 60 molar ~ of these
radicals being methyl radicals, having a viscosity of
100 to 500,000, preferably of 1,000 to 200,000 mPa.s at
25-C,
- (B): at least one organohydrogenopoly-
siloxane chosen from the liquid homopolymers and

37 2036272
copolymers which are straight-chain or have a network
structure, which have, per molecule, at least 3
hydrogen atoms bonded to different silicon atoms and
the organic radicals of which, bonded to the silicon
atoms, are chosen from methyl and ethyl radicals, at
least 60 % of these radicals being methyl radicals and
the product (B) being used in an amount such that the
molar ratio of the hydride groups to the vinyl groups
is between 1.1 and 4,
- (C): a catalytically effective amount of a
platinum catalyst.
Still more preferentially, up to 50 % by
weight of the polymer (A) i8 replaced by a copolymer
having a network structure and comprising the
trimethylsiloxy, methyl~inylsiloxy and SiO~/2 units, in
which 2.5 to 10 molar % of the silicon atoms carry a
vinyl group and in which th~ molar ratio of the
trimethyl~iloxy groups to the SiO~/2 group is between
0.5 and 1.
The compositions according to the invention
~ay also comprise reinforcing or semi-reinforcing or
packing fillers (E), which are preferably chosen from
the ~iliceous fillers.
The reinforcing fillers are chosen from the
silicas produced by combustion and the silicas produced
by precipitation. They have a specific surface area,
determined by the BET methods, of at lea3t 50 m2/g and
preferably more than 70 m2/g, an average size of the

2036272
38
prLmary particles of below 0.1 ~m (micrometre) and an
apparent density of less than 200 g/litre.
These silicas may be incorporated as such or
after having been treated with the organosilicon
compounds customarily used for this application. These
compounds include methylpolysiloxanes, such as
hexamethyldisiloxane and octamethylcyclotetrasiloxane,
methylpolysilazanes, such as hexamethyldisilazane and
hexamethylcyclotrisilazane, chlorosilanes, such as
dLmethyldichlorosilane, trLmethylchlorocilane, methyl-
~rinyldichlorosi ~ne and dLmethylvinylchlorosi?ane, and
alkoxysilane~, such as dimethyldimethoxysilane,
dimethylvinylethoxysilane and trimethylmethoxysilane.
During this treatment, the silicas may
increase their initial weight by a proportion of up to
20 %, preferably about 18 %.
The ~emi-reinforcing or packing fillers have
a particle diameter of more than 0.1 ~m (micrometre)
and are preferably chosen from ground quartz, calcined
clays and diatomaceous earths.
Generally from 5 to 100 parts, preferably
from 5 to 50 parts, of filler (E) may be used per 100
parts of the sum of the organopolysiloxanes (A) + (B).
The polyaddition compositions are generally
3tored in two packaging~. In fact, they crosslink from
the time at which all of these constituents are mixed.
If it is desired to delay this crosslinking in order to
obtain good homogenisation of the active substance, it

39 2~36272
is possible to add an inhibitor for the platinum
catalyst to the composition.
These inhibitors are well known. In
particular, it is possible to use organic amines,
S silazanes, organic oxLmes, diesters of carboxylic
diacids, acetylenic alcohols, acetylenic ketones or
vinylmethylcyclopolysiloxanes (see, for example,
US-A-3 445 420 and US-A-3 989 667). The inhibitor is
used in an amount of 0.005 to 5 parts, preferably 0.01
to 3 parts, per 100 parts of the constituent (A).
In order to obtain a good distribution
homogenisation of the active substance, it is in fact
desirable for the silicone matrix to have a certain
viscosity of the order of 5,000 to 30,000 mPa.s at
25~C.
Such a vlscosity may be obtained by pre-
crosslinking, this pre-crosslinking being blocked at
the desired viscosity by the addition of an inhibitor.
Sufficient time is then available to homogenise the
active substance well within the silicone matrix.
Crosslinking is then completed by heating the
matrix to a temperature such that the inhibitor no
longer has an effect on the catalytic action of the
platinum.
The compositions according to the invention
may be malaxated cold as such and be shaped, in
particular moulded into various form~.
The water-soluble auxiliary agent which may

2036272
be used according to the invention must at one and the
same time be highly soluble in water and chemically
inert towards the active substance and the silicone
material. This auxiliary agent may be an inorganic or
organic salt, preference being given to the inorganic
salts, in particular the alkali metal and alkaline
earth metal salts of strong acids, such as, for
example, sulphuric, hydrohalic or nitric acid. The
following may be mentioned by way of example: alkali
metal, in particular sodium or potassium, and ammonium
chlorides, iodides, sulphates or nitrates.
The four groups of silicones described above
have the same property, that is to say when they
contain an active substance and an auxiliary salt a
defined above, dispersed in a uniform manner, the
compositions obtained are able to release the active
substance in a controlled manner into an aqueou~ medium
or into a humid atmosphere, as well as into the plant
to be treated over a prolonged period.
Processes for the production of the
compos~tions according to the invention by intimate
mixing of the polysiloxane base~ with the active
substance in water-soluble and preferably solid form,
followed by production of the filled elastomer have
been described. This latter technique is preferred but
any other technique enabling these compositions to be
obtained may be used~
The considerable advantage afforded by the

41 2~3~272
silicone matrix is therefore that it is very easy to
extrapolate the continuous diffusion of the active
substance after measurement of the amount released
representing 10 to 15 % of the initial substance, ~ince
it is known that the diffusion kinetics are of the
order of 0 and that at least 80 ~ of the active
substance will be released in accordance with these
kinetics.
The composition according to the invention
compri~ing the ~ilicone material containing the active
su~stance and the auxiliary salt may be in the rigid or
to a greater or le~ser extent elastic solid form. It
may be in very varied shapes, depending on the
envisaged applications, particularly for the active
lS substance, and the shape of the plant to be treated as
well as on the problem to be resolved.
It may, in particular, be in the form of a
sheet, tape or ~trip which may be applied either
entirely against any part of the plant to be treated or
at a distance from but in the vicinity of the latter,
in a gaseous atmo~phere, preferably in humid air, or in
an aqueou~ liquid medium.
It may also be advantageous to use the
composition according to the invention in the form of
units of small dimen~ions and of variou~ shape~, such
as cubes, parallelepipeds, rectangles, cylinders or
~pheres, the fundamental parameter~ of which are as
follo~Js:

42 2036272
- the nature of the active substance,
- the average diameter (particle size) p of
the particles of the acti~e substance in the preferred
case where the latter is a solid,
- the concentration c of the active
substance in the matrix,
- the ratio r of the surface area to the
volume of the unit,
- and, in a general manner, according to the
geometry of the system.
The nature of the active substance and its
particle size determine its rate of diffusion R through
the matrix.
The smaller i~ p the slower is R, and vice
versa.
The higher i~ c the higher is the flow of the
active substance, a~d vice versa.
The higher is r the higher i~ the flow of
active substance eluted, and vice verqa.
8y means of routine experiments, those
skilled in the art are able, without difficultr,
rapidly to arrive at the desired result by
extrapolating the theoretical elution time which will
correspond to the actual diffusion time of the active
2S substance.
Active substances which may be mentioned
which have an agricultural biological action and are
insoluble or soluble in water are aqrochemical active

43 ~03~272
substances such as fungicides, bacteriocides,
algicides, molluscicides, insecticides, nematicides,
herbicides, growth regulators or manures or
fertilisers.
The following may be mentioned as examples of
agrochemical active substances: fungicides, such as
sodium tris-O-ethylphosphonate, calcium tris-O-ethyl-
phosphonate or aluminium tris-O-ethylphsophonate
(Phosethyl-Al), salts of phosphorous acid, in
particular the alkali metal and alkaline earth metal
salts, growth regulators, herbicides, such as
substituted phenoxyacetic or phenoxypropionic acids,
such as 2,4-dichlorophenoxyacetic acid (2,4-D),
2-chloro-4-methylphenoxyacetic acid (MCPA),
2,4-dichlorophenoxy-2-propionic acid (2,4-DP) and
2-chloro-4-methylphenoxy-2-propionic acid (MCPP or
mecoprop), and their alkali metal, alkaline earth metal
or amine or alkanolamine salts, inorganic alkali metal,
alkaline earth metal or amine salts, or N-(phosphono-
methyl)glycine alkanolamine (glyphosate) and
bipyridyldiylium halides (diquat and paraquat), and
insecticides such as aldoxycarb.
The following examples illustrate the
compositions according to the invention and their
application, without thi~ illustration restricting the
scope of the invention.

` 44 2~3~272
Example 1:
Preparation of the composition:
The following ingredients are intimately
mixed with the aid of a malaxator: -
S * a dimethylmethylvinylpolysiloxane gum (A)
(100 parts) blocked at each of its two ends by a
trimethylsiloxy unit and comprising in its chain
99.8 molar % of dimethylsiloxy units and 0.2 molar ~ of
vinylmethylsiloxy units and having a visc08ity of
10 million mPa.s at 25C;
* filler tB) (43.5 parts), which is a treated
silica produced by combustion D4 (ocatamethylcyclo-
tetrasiloxane) having a BET specific surface area of
300 m2/g;
* a straight-chain dimethylpolysiloxane
(1 part) blocked at its two ends by dimethylhydroxy-
~iloxane groups and having a viscosity of 50 mPa; 8;
* octamethyltetracyclosiloxane (0.2 part);
and
* micronised aluminium ethylphosphite (c)
(36.1 parts).
Malaxating is stopped 30 minutes after the
end of the introduction of the silica. The homogeneous
composition which has just been prepared and which is
termed the ma~ter mixture (M~) i8 removed from the
malaxator.
The ~M is transferred to a cylinder mixer in
order to incorporate, per 100 parts of MM:

- 203~272
* 2,5-dLmethyl-2,S-di(tert-butylperoxy)hexane
tO.5 part).
The catalysed composition detaches easily
from the cylinders of the mixer.
It is then injected under a pressure of 5,000
to 20,000 psi into a mould having the following
dimensions: 1 20 cm, b = 20 cm, d = 0.2 cm.
Crosslinking is carried out at 150C for a
few minutes.
Strips 5 cm long and 2.5 cm broad are then
cut for the in vitro release test.
Two in vitro release tests are carried out:
* release in water, and
* release in a humid atmosphere.
Ex~erimental protocol for the determination of the
elution kinetics in water:
The matrix i~ placed in a vessel containing
100 ml of distilled water, thermostat-controlled at
2~C.
The vessel is fitted with a magnetic stirrer
system which i~ set in 810w rotary motion (100 r~v/min)
ensuring the homogeneity of the solution. It is covered
by a cover in order to minimise the evaporation of
water.
1 ml samples are taken daily during the
initial elution period and weekly at the end of 15 days
of elution.
The concentration of aluminium ethylphosphite
,. ~
- ~

46 203~272
is determined by determination of aluminium by atomic
absorptlon.
The results for the elution kinetics are
collated in Table 1.
s
TLme (days) QJQo
0.3 0.8
2 5.5
6 11.74
9 15.72
13 20.63
25.08
42 44.57
The controlled release curve is given in the
\ appended Figure 1.
ExDerimental protocol for the determination of the
elution kinetics in a humid atmosphere:
In order to confirm that the active principle
incorporated in the elastomer is able to be dispensed
into the ambient humid medium, the following test wa~
carried out:
The matrix i~ suspended with the aid of a
stainle~s steel boat in a confined medium where an
atmosphere of 100 ~ relative humidity is maintained.
The release is monitored by determination of aluminium
in the aqueous phase (100 ml) contained in ~he said
.
; .
.: -;:

- 47 2036272
vessel.
The results for the elution kinetics are
collated in Table 2.
TLme (days)Q/Qo (%)
42 2.55
5.05
79 13.17
84 13.66
91 14.06
There is a 42 day latent period before
elution of the active qubstance.
Example 2:
PreDaration of the com~osition:
The following ingredients are intimately
mixed with the aid of a malaxator:
~ a dimethylmethylvinylpolysiloxane gum (A)
(100 parts) blocked at each of its two ends by a
trimethyl~iloxy unit and comprising in its chain
99.8 molar % of dimethylsiloxy unit3 and 0.2 molar % of
vinylmethylsiloxy units and having a visco~ity of 10
million mPa.s at 25-C;
* filler (~) (43.5 parts)~ which is.a treated
silica produced by combustion D4 (octamethylcyclo-
tetrasiloxane) having a BET specific ~urface area of
300 m2/g;
~. :
:

48 20362~2
* a straight-chain dimethylpolysiloxane
(1 part) blocked at its two ends by dLmethylhydroxy-
siloxane groups and having a viscosity of 50 mPa.s;
* octamethyltetracyclosiloxane (0.2 part);
* micronised aluminium ethylphosphite (c)
(44.4 parts); and
* ammonium sulphate (33.3 parts) having a
particle size smaller than 50 ~m.
Malaxating i9 stopped 30 minutes after the
end of the introduction of the silica. The homogeneous
composition which has ~ust been prepared and which is
termed the master mixture (MM) is removed from the
malaxator.
The MM i8 transferred to a cylinder mixer in
order to incorporate, per 100 parts of MM:
* 2,5-dimethyl-2,5-dittert-butylperoxy)hexane
~0.5 part).
The catalysed composition detaches easily
from the cylinders of the mixer.
It i3 then in~ected under a pressure of 5,000
to 20,000 psi into a mould having the following
dimen~ions: 1 20 cm, b = 20 cm, d = 0.2 cm.
Crosslinking is carried out at 150C for a
few minutes.
Strip~ 5 cm long and 2.5 cm broad are then
cut for the in vitro release test.
Two in vitro release tests are carried out:
* release in water, and

49 2036272
* release in a humid atmosphere.
_lution kinetics in water:
The procedure is as in Example 1.
The results for the elution kinetics are
collated in Table 3.
TLme (days) QfQo (%)
_
1 3.31
2 7.72
3 7.87
4 8.25
7 11.79
34.11 .
I5 14 51.52
17 60.20
21 . 69.55
_
The controlled release curve is given in the
appended ~igure 1.
Elution kinetic~ in a humid atmosphere:
The procedure i8 as-in Example 1.
The results for the elution kinetics are
collated in Table 4. It can be seen that the latent
period has ~ubstantially declined.
~.

`- 203~272
.TLme (days) Q/Qo
1 0.00
2 0.42
3 0.51
4 0.6
7 2.66
5.59
14 7.35
17 8.2
21 9.54
24 ~ 11.95
12.77
31 13.46
38 14.56
51 26.64
59 . 30.41
,
The corresponding elution curve i~ qiven in
Figure 2.
Exam~le 3: Composition:
The following ingredients are intimately
mixed with the aid of a malaxator:
~ a dimethylmethylvinylpolysiloxane gum ~A)
(100 part~) blocked at each of its two ends by a
trimethylsiloxy unit and comprising in it~ chain
99.8 molar % of dimethylsiloxy units and 0.2 molar % of
'~ :
`

51 203~2~2
vinylmethylsiloxy units and having a viscosity of 10
million mPa.s at 25C;
* filler (B) (43.5 parts), which is a treated
silica produced by combustion D4 (ocatamethylcyclo-
tetrasiloxane) having a BET specific surface area of
300 m2/g;
* a straight-chain dimethylpolysiloxane (1
part) blocked at its two ends by dimethylhydroxy-
siloxane groups and having a viscosity of 50 mPa.s;
* octamethyltetracyclosiloxane (0.2 part);
* micronised aluminium ethylphosphite (c)
(48.1 parts); and
* ammonium sulphate (48.1 parts) having a
particle size smaller than 50 ~m.
Malaxating is ~topped 30 minutes after the
end of the introduction of the silica. The homogeneous
composition which has ~ust been prepared and which is
termed the master mixture (NN) is removed from the
malaxator.
~he M~ is transferred to a cylinder mixer in
order to incorporate, per 100 parts of M~:
* 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane
(0.5 part).
As in Example 2, strips 5 cm long and 2.5 cm
broad are prepared for the in vitro release test.
Two in vitro release tests are carried out:
* release in water, and
* release in a humid atmosphere.
'

2036272
52
Elution kinetics in water:
The procedure is as in Example 1.
The results for the elution kinetics are
c:ollated in Table 5.
s
Time (days) Q/Qo
1 3.30
2 7.84
3 7.76
4 14.72
7 25.55
38.24
14 59.54
17 65.46
21 j 72.85
The controlled.release curve i~ given in the
appended Figure 1.
Elution kinetics in a humid atmospheret
The procedure is as ~n Bxample 1.
The results for the elution kinetic~ are
collated in Table 6. It can be seen that the latent
period is virtually non-existent.

2036272
53
_
. TLme (days) Q/Qo (%
_
1 0.00
2 0.57
3 0.89
4 1.52
7 4.57
7.4~
14 7.93
17 10.43
21 9.90
24 10.42
29 13.49
51 25.52
~9 32.56
i . .
\ The corresponding elution curve is given in
Figure 2.
ExamPle 4:
The procedure is as in Example 3 except that
ammonium sulphate (48.1 parts) is replaced by potassium
sulphate (48.1 parts) having a diameter smaller than
50 ~m.
Rinetics in water:
The procedure is as in Example 1. The results
for the elution kinetics are collated in Table 7.
.
.,, .`'' '

2036272
54
TLme (days) Q/Qo (%)
1 4.13
2 8.61
3 11.93
4 15.61
7 20.46
23.14
L0 14 32.5
17 34.98
21 39.21
The controlled release curve is given in the
appended Figure l.
Elution kinetics in a humid atmosDhere:
The procedure is as in Example l.
The re~ults for the elution kinetics are
collated in Table 8.

2036272
Time (days) QJQo (%)
.
O . 00
2 0.00
3 0.00
4 0.00
7 2.09
4.44
14 5.91
17 8.77
~1 11.95
24 13.04
29 18.28
31 18.17 ~:
38 23.24
51 30.26
59 .. 33.88
The latent period is slightly longer with
this ~alt than with ammonium sulphate.
The corre~ponding elution curve i~ given ~n
Figure 2.
Example 5:
* Preparation of comPonent A:
The following constituents are homogenised at
ambient temperature in a malaxator:
a) Silicone resin (25 parts) comprising 40 molar % of
,

2036272
56
(C~3)3 SiOl~ units, 6 molar % of ~CH3) (CH2 = CH)SiO2~2
units and 53.5 ~ of SiO4/12 uni.ts,
b) a dimethylpolysiloxane oil (75 parts) blocked at
each of the ends of its chain by a (CH3) (CH2 = CH)SiO"2
unit and having a viscosity of 3,500 mPa.s at 25C, and
c) platinum metal (40 ppm calculated by weight),
supplied by a 0.25 % solution of hexachloroplatinic
acid prepared by stirring hexachloroplatinic acid ~0.6
part), isopropanol (10 parts), xylene (55 parts) and
- 1~ 1,1,3,3-tetramethyl-1,3-divinyldisiloxane (6 parts) at
ambient temperature.
* Preparation of component B:
The following constituents are homogenised at
ambient temperature in a malaxator:
d) liquid hydrogenated silicone resin (45 parts)
prepared by hydrolysis of ethyl silicate and
(CH3) 2 HSiCl. in amounts corresponding to one mole of
SiO per two moles of (CH3.)2 ~SiCl in solution in
toluene. This resin therefore has a theoretical molar
ratio of (CH3)HSiO1/2 units of 2 and an actual molar
ratio of 2.23,
e) the resin a) (12.5 parts) from portion (A), and
f) the vinyl-containing oil b) (37.5 parts) from
portion (A).
The elastomer composition is obtained by
mixing component A (10 parts) with component B
(1 part).
.

203627~
57
* Preparation of the com~osition of ExamPle 5:
Aldoxycarb (25 parts) having an average
particle size of less than 50 ~m is incorpoxated into
1:he elastomer composition (lOQ parts). The mixture is
<;tirred, under vacuum, for 15 minutes in order to degas
the mixture. The whole is then poured into a mould
preshaped to the required dimensions, that is to say:
l = 5 cm, b = 2.5 cm, d = 0.2 cm.
The mixture is heated for one hour at 60 J C .
Two in vitro release tests are carried out:
* release in water, and
* release in a humid atmosphere.
Elution kinetics in water:
The procedure i8 as in Example 1. The release
of the active substance is monitored by determination
of aldoxycarb by liquid chromatography.
- The resu}ts for the elution kinetics are-
collated in Table 9.

203~272
58
.Time (days) Q/Qo (~)
_
1 0.6
2 0.78
3 0.98
4 1.12
7 1.~6
11 1.89
21 2.68
31 3.5
37 3.86
43 4.25
It can be pointed out that the elution is
very slow.
Blution kinetics_in a humid atmosphere: -
The procedure i8 as in Example 1 and the
release of the active substance is determined by
determination of the aqueous phase by liquid
chromatography. Under these conditions, no trace of
active sub tance is observed at the end of 45 days.
Example 6:
Aldoxycarb (28.6 parts) having a particle
qize of less than 50 ~m and sodium chloride ~14.3
parts) having a particle size of less than 50 ~m are
added to the elastomer composition (100 parts) prepared
in accordance with Example 5.
~' . ,. ' ' ~ ,,.
. . .

2~36272
59
Matrices having the following dLmensions are
prepared in accordance wi~h Example 5: 1 = 5 cm,
b = 2.5 cm, d = 0.2 cm, wh~.ch are then placed in water
and in a humid atmosphere for elution.
Elution kinetics in water:
The results for the elution kinetics are
collated in Table 10.
Time ~days) Q/Qo
1.4
4 ~.39
8 7.6
12 12.2
15.7
19 18.9
22 21.0
22.2
29 24.3
27.0
__ _
It may be pointed out that in the presence of
NaCl the elution is greatly accelerated (factor of
close to 7).
Elution kinetics in a humid atmosphere:
In the presence of salt, the olution of
aldoxycarb is possible in a humid atmo~phere. However,
a latent period of 4 days is observed.

2 7 2
The results for th~ elution kinetics are
collated in Table 11.
Time (days) Q/Qo (%)
1 0.0
4 0.04
8 0.09
12 0.08
10 15 0.34
19 0.4
22 0.4
0.38
29 0.77
15 35 3.1 '
- However, the elution remains very slow.
,Example 7:
Aldoxycarb (33.3 parts) having a particle
size of le3s than 50 ~m and sodium chloride (33.3
parts) having a particle size of less than 50 ~m are
added to the elastomer composition (100 part3) prepared
in accordance with Example 5.
Matrices having the following dimensionss
1 = 5 cm, b = 2.5 cm, d = 0.2 cm, are prepared in
accordance with Example 5, which are then placed in
water and in a humid atmosphere for elution.

203~72
61
Elution kinetics in water: ~
The results for the elution kinetics are :
collated in Table 12.
STLme ~days) Q/Qo (%)
1 1.6
4 6.1
8 12.5
12 17.2
20.3
19 22.7
Exam~le 8: Biological efficacy on plants.
Silicone collars ~1 = 60 cm, b = 2.75 cm,
d = 0.2 cm; weight - 40 g) obtained by the method
described in Bxample 2 but containing the active
subqtance in an amount of 25 % (55.5 parts, which is
10 q, of aluminium tri-O-ethylphosphonate) and the co-
salt in an amount of 15 % (33.3 parts, which is 6 g, of
ammonium ~ulphate) are fixed on 10 trees (clementines)
at the level of the graft point (10 further trees not
provided with these collars serve as controls) at time
Tl.
Six collars are fixed in a superimposed
manner on each tree in order to have a dosage of 60 g
of active substance per tree.
At time Il = Tl + 15 days; or 15 days after

2036272
62
positioning of the collars, several inoculations with
phytophthora citrophthora (3 to 5 inoculations per
tree) are carried out on all of the 20 trees by
incrustation of a mycelium fragment in the sub-cortical
S zone of the larger branches. The initial diameter of
the canker is of the order of 1 cm.
The growth of the pathogenic fungus is
checked at I1 + 2 months and Il + 5 months. The length
reached by the canker is then measured; this length is
expressed in cm in the form of average length for each
of the two series of 10 trees.
The table giving the following results is
then obtained:
EFFICACY AVERAGE LENGTH OF THE
CANRERS (cm)
~Inoculation .
Il = Tl + 15 days) Il + 60 Il + 150
Control tree~ (10) 7.9 ~ 10
Trees treated with
the invention (10) 4.3 4.9
A reduction in the rate of implantation of
the canker is observed in the first few months tfactor
of 2) and the arrest of the propagation of the fungus
is observed in the longer term (factor of 2).

203~27~
63
The treatment as carried out with the product
of the invention proves effective in terms of immediate
activity but also over time tcontrolled and continuous
release of the active principle).
It proved possible to confirm this prolonged
release by measurement of the residues of the active
substance and its metabolite in the leaves of the tree,
which also proves the passage of the active substance
into the vital system of the tree.