CA2077927A1 - Polysiloxanic stabilizers containing sterically hindered phenol groups and reactive groups - Google Patents

Abstract

POLYSILOXANIC STABILIZERS CONTAINING STERICALLY HINDERED PHENOL
GROUPS AND REACTIVE GROUPS

Abstract of the Disclosure Polymeric stabilizers with a polysiloxanic structure contain sterically hindered phenol groups and reactive groups capable of binding themselves to the polymeric structure to be stabilized.
These polymeric stabilizers are particularly suitable for applications which require the non-extractability of additives due to solvents, fats or soaps.

Description

~7~927 The present invention relates to the stabilization of organic polymers.
In particular it relates to a new group of polysil~xanic stabilizing additives containing sterically hindered phenol groups in the molecule, the procedure for the preparation of these stahilizing compounds and the stabilized polymeric compositions.
It is ~nown that organic polymers are inclined to degrade over a period of ~ime due to exposure to atmospheric agents, and that they are also easily subJect to degradation during operating and transformation processes owin~ to the high temperatures reached.
This degradation is reflected in a decrease o~ the physical charac~eristics o~ the polymer, such as, for 2~ampl2, a decrease in the breaklng load and ln fle~ibility, and with alterations in the optlcal propertles o~ the ~nd product.
To counteract these forms of degrada~ion it i~ common practice to introduce stabilizing compounds lnto the polymer.
A group of compounds which is widely used for this purpose ls that of s~erically hindered phenol~
The probl~ms ~hich arise in the s~abilization o~ organio -~

" ` ~ ; ' ' ' "~' . , ';

2~77~f~7 polymers ba~ically derive from incompatibility b~tween polymer and stabilizer and the discharging of the stabilizer from the polymer. It is therefore necessary to have stabilizing compounds which are as compatible as pc~ssible wi~h the polymer to be stabilized, and which are capable of remai.niny inside the polymer.
U.S. Patent 4.888.375 and European Patent Application 182.415 describe sterically hindered phenolic antioxidant additives having a hydrolizable sillcic function in the molecule.
These compounds, after hydrolysis of the sililated function, are capable of interacting among each other or with a solid support, producing complex resinous structures capable of remainlng for a period of time inside the oryanic polymer in which they are incorporate~.
In addition, stabilizing compounds of a polymeric nature, including sterically hindered phenol groups attached to the silicon atoms of a polysiloxanic chain are described, for example, in U.S. Patents 4 . 430 . 235 and 4 . 879 . 378 .
However, eve~ if the incorporation of the st~bilizer in a polymeric structure allows for its homogeneous m~ing inside ~he polymeric materials ~o be stabilized, and this inco~pora~ion is capable of remaining inside the polymer for ~ period of time, ~here are certain partlcular cases when these stabilizers do not g~ve sufficient guarantee for the , ~
-;
' ~77~27 uses or w~ich they are destined.
This is the case, for example, when the end products are destined to come into contact with particular substances or solvents which are capable of extractlng the stabilizing siloxanic polymer, or to come into contact with food when the total non-mi~ration of the add~iYe towards the surface of the product must be guaranteed.
A new group of stabilizers which overcomes the above disadvantages has now been surpris$ngly found.
The present invention consequzntly relates to a new group of stabilizing compounds o~ a polymeric nature composed o~ a polysiloxanic chain having, besides sterically hindered phenol groups, reactive organic groups capable of chemically binding themselves to the polymeric structure to be stabilized.
The present invention also relates to a process for the preparation of the above polymeric sta~ilizers.
Furthermore, the present invention relatP~ to polymeric compositioas containing an organic polymer and a stabilizing quantity of the above polymerlc stabilizers.
In accordancP with this, the first aspec~ of the present invzntion relates to polymeric stabilizing compounds having the following formula:
MX~YpZqM~ (I) wherein 2~77927 Il' X ~ --o--si-- ~ --03/2SI--R2 ~z E~L
Y = o $i or _o3~2SI -R~ R~

z = -O-Si-, -O3/2SI - or -O~2Si-R~
~' M ~ Rn-Si-, ~, R3, R' M'- -OM, M and M' can optionall~ form together a direct bond ~hus produclng a cyclic structure, Fl is a phen~l or a line~r or branched alkyl radical containing ~rom 1 to 20 car~o~ atoms, F~ is a reacti~e organic group capabla of chemicall~ binding itsel~ to the polymQric ~true*ure to ~B 8~biliZ8d, R3 is a linear or branched alXyl radical cont~ining from 1 to 6 car~on ato~s, R~ is a rad~c~l ~el2c~ed from the group i~cludlng:

R5 ~ :-~ ' , . .

~77~7 RC 3, R5 ~ (0)n~-R8 -wherein, F~ and R6, ~he sa~e or d~fferent, are al~yl radicals, linear or branched, con~aining from 1 to 10 carbon atoms, R7 ls an akyl ne radical, llnear or branched, containlng from 3 to 10 carbon atoms, R8 is an alkylene radical, linear or branched, containing from 1 to 10 carbon atoms, or a biradical selected from -R~-COO-R1o~, -R~-coo-Rlo-s-Rll- and -R~o~S~R~
R~, Rlo and Rll, the same or different, are alXylene radicals, line~r or branched, containlng ~rom 2 to 10 c OE bon atoms, R' is a phenyl or an alkyl rad~cal, line æ or branched, containing ~rom 1 ~o 10 carbon atoms, RN is oqual to R', R~ or R~, m, p, the same or differen~, are integess from 1 to 50, q is an integer betwe~n O ~nd 50,.
n is equal to O or 1.
R~ is pr~ferably selected from radic~l~ cont~inlny a car~on-carbon doubl0 bond, an epo~ rin~, a sulphide group, or an aminic gr p.

~77g27 ~ ore preferably, R~ is a radical selected ~rom the group including:
. C~I2=CH-C}I3 C~2=C-cOO~ 2) 3 ~0~
C~I2--C~ --( CH2 ) 3-~IS--( CHz ) 3 }IZ~- ( CH2) 3--V
When R~ is an alkyl radical, it preferably contains from to 10 car~on atoms t and even more prefera~:11y fro~ 1 to 3 carbon atoms. Particularly preferred is the case where R~ is methyl .
Rs and R,S are preferably braslched, and even more preferably are t-~utyl radicals.
The stabilizing compound~; o~ ~he pr~ent invention are polymers having a rando~ distribution o:e ~os o~ic units X, Y
and Z.
They ~ay also have hydro~ r alko~yl gro~ps oll 'che silicon ato~ whid ar~ ~ot hown i~ t:h~ ge~eral ~orl~ulae given.
The co~pounds corresponding to genoral fomlula (I) can ba : , , " . , ~
, 2~77~,~7 obtained, ~or example, by the reaction of a mixture of compounds having the following formulae:
(R~ )n Si-(R~)3-n (II) R~

(R~ )n Si (R~ I I )3-n (III) R"
optionally in the presence of compounds havin~ the following formulae:
(R~.)r li--(R~ ~ )4-r (IV) R~
R"--Si--R" ' (V) wherein R''' is 0~ or C1, r is equal to 0, 1 or 2, and ~, F~, R~, R', Rn, and n have the meaning prev~ously defined.
The compounds having formula (II), (III), (IV) and (V) hydrol~ze under ~land conditio~s generating ~llan31~ whiCh ca~
be conden~ed among each other to form polysiloxanic structures which are more or less complex depending on the ~umber o~ R''' group~ linked to the silicon a~om.
By suitably varying ~he ratios b~tween ~he compounds having formula (II), tIII), (IV) and (V) which are reacted, it - . . .

- : . - - . :. , .

:

2~7~92~

is possible to vary the m, p, q values in the compounds having formula (I~ obtained.
In ~articular, depending o~ the quantities us~d o~ a compound having formula (V), which acts as chai~ terminator, products can be obtalned with structures more or less comple~
and with higher or lower molecular weights.
The above hydrolysis and copolymerization reaction is carried out in water or in a mi~ture of organic solvent and water in ratios of up to 10:1.
When in the reagents having formula (II), (III), (IV) and (V), R''' is equal to OR3, the process is carried out at a temperature ranginy from 20 to 100C for a period of 2-20 hour~, until the complete hydrolysis of the reagents. At this stage the polymerization reaction is carried out at the boiling point of the solvent, in the presencs of a condensation catalyst, eliminating the reaction water and alcohol by distillation. The reactton is then continued at reduced pressure (0.1-50 mm Hg ) at temperatures ranging from 60 to 140C. The polymerization reaction generally requires a period of 2 to 10 hours.
When, on the other hand, R''~ is equal to Cl, the reaction is carried out under stirrlng at tamperatures ranging from 20 to 120~C for a period of 1-~ hours. The product is recovered from the organic phase after eliminating the solvent by distillatlon at reduc~d pressure.

' ~7~27 Comm~tcial products such as vinylmethyldichlorosilane, vinyltriethoxysilane, 3-mercaptopropyltrimetho~ys~lane, 3-.--glycldyloxyproyltrimethoxysilane, 3-methacryloxypropyltri-chlorosilane, 3-aminopropyltriethoxys;ilane, may be used as reagents having formula (II).
With respect to the reagents havin~ formula (II~), these can be synth~sized, for example, as described in U.S. Patent 4.888.375 in the name of same Applicant.
Examplss of alko~ysilanic compounds having formula (III) are those having the following formulae:
t OC~2C~3 ~ ~ (CH2)2COO(CX2)3S\-CX~
t . C~2c~3 HO~ ( C}I2. ) 2 COO ( C~2 ) 3 S i- ( C~2 C~3 ~ 3 oC~I2CX3 ~ /
xo~coo (c~2) 3si\C~3 t OC~2C~3 t 1~0~(~2)3Si~(C~3~3)3 t ~ ~C~C~3 ~O ~(C~2)3Sl\~3 t - 10 - OC~2C~3 -2~77~27 t.

r.O~ (C~2 ) 2COC ( CE~2 ~ 3 ~5~ (C ~I2 ) 3Si- tOC~;3 ) 3 t __ wherein t is a ter-butyl radical.
Commercial products such as dimethyldichlorosilane, diphenyldichloro~llane, dimethyldietho~y~ilane can be used as reagents having formula (IV).
Co.~ercial products such as trlmethylchloros~lane, trimethylethoxysilane, vinyldimethylethoxysilane ~ay be used as reagents having formula (V).
The organic solvent is selected rom the group lncluding ethers, s~ch as tet~hydrofuran (THF), alcohols such as ethanol, aliphatic hydrocar~ons, such a~ heptane, alicyclic hydrocar~ons, such as cyclohe~ane, or aromatic hydrocar~on~s, such as toluene.
Condensation catalysts s~rhich can be used are, for example, dibu~yltindllaurate, zinc octancat , t$n ~ctanoate or an alXallne hydro~ide. ~he concent~;~tion of the catalyst ~ s wit~in the ra~ge of O.OQ5-t).5~ by w~ight ~rith r~spec~ to th~
reagents charged.
ThQ ~oly~ additi~3 of the present l~enti a~
character~zed ~ at they have a s~ctl~re fus~ whlch i~
capable o:E lin}~g to the polymerlc ma~ or to t~a reinforc:~g materlal o t~e plas~ic product o~ e ~e~., thU5 pr~v~nt~ng the. s~llizer from belng discharged from the matrix or improving the adhesion between matrix and support.
As said before, these characteristics, together with the capacity of delaying the degradation of the polymers, are particularly important when the non-migration of the additive and lts non-extractability with sol~ents, fats or soaps are required.
This is the case, for example, when polymeric end products are destined to come in contact with food, or in the stabilization of polymeric mixtures or copolymers, or also for the production of composite end products composed of multilayers of organic polymers or polymer and inorganic support.
In this latter case, in fact, the migration of the additive almost always causes a detachment of the various layers, a loss o~ mechanical characteristics of the product and a more rapid degradation of the oryanic material.
The siliconic products of the present invention are generally added to the organic polymer to be stabilized in the compounding phase.
More generally the stabilizers of the present invention are added as additives either in th~ final phase of the syn~hesis process or in the production phase of the end-products.
The most widely used me~hod is to add the products in the preparatory phase of the end-product because i~allows for the ' ' ' ' ' `

2~77~7 level of addition to correspond to the characte-istics o~ the product to be obtained.
. The polymers to be stabilized can be polyolefins (LDPE, LLDPE, HDPE, PP) and their copolymers, the copolymers o~ these with acrylic acid or maleic anhydride, polyesters, polyamides, polycarbonates, polyurethanes, terpolymers EPDM and ABS, svnthetic rubbers.
One of the applications o~ this technology is the production of products made of low density polyethylene (LDPE) cross-linked during the extrusion phase.
When the additive of the present invention has R2 groups containing a double reactive bond or a sulphide group, the grafting o~ the additive to the polymeric matrix takes places owing to the formation of radicals, and can possibly be induced by the presence of small quantities of organic peroxide during the operating phase of the polymeric material ~t high temperatures.
The stabilizers of the present invention may additionally contain one or more additives selected, for e~ample, from antioxidants, heat and light stabilizers, metal disactivators, basic co-stabilizers and nuclea~ing agen~s.
In particular, they can be used in combination with additives based on sterically hindered amines, such as those corresponding to the trade-names Uvasil 299, ~inuvin 770, Tinuvin 622, Chi~assorb 944, or phosphites andJor phosphonites ~ ' ' ' ' ' ' ' ! ,~' .. ',..,' '"' ' ' ',`, ~

2~77~7 such as those corresponding to the trade-names Ultrano~ 626, W~ston 618, Alkanox 240, Sandostab PEYQ, or organic compounds containing sulphur such as distearyl thiodipropionate and dilauryl thiodipropionate.
The quantlty of silioonlc additive nonmally used varies from 0.05% to 1~ by weight o~ the weight of the resin to b2 stabilized. The preferred quantlties vary from 0.1~ to 0.8% by weight of the welght of the resin.
The fo~lowing examples provide a bPtter illustra~ion of the present invention but do not limit it 1~ any way.
EXAMP~E 1 PreDaration of a stabilizer corresDondlnq to the followina formula:
C~3 C~3 M(o-si )m~(o-li-)p-M

IX (I 2)3--C-(c~2)2 CX2 t wherein M is H or C~3CX~-, M' $s OH or C~3CH20- ar~ t is ter-butyl.
~ 5.0 ml of ethanol, 11.1 g (O.025 moles) o~ a co~pound having formula (III) ~herein R~ is methyl, ~ ls e~hyl and R~

_ . . . . _ . . _ . . . . . .
is ~ (CXz~COO~CXz~3-, t ,,: ' ~ ' ' '`

2~37~27 1. o ml of diethoxy methylvinylsilane and 5.0 ml of H2O are charged into a flask equipped with a stlrrer, cond~nser and .~hermometer.
The solution ls kept at 65C until gas chromatograhic analysis no longer reveals the presence of the reagents, i.e for about 3 hours.
The ethanol is then removed by di.stillation, 0.05 ml o dibutyltindilaurate are aaded and the mixture ls brought to a temperature of 120C at reduced pressure (5-12 mm Hg) for a pPriod of 3 hours.
A colourless resinous product is obtained, having an average osmometric molecular weight o~ 1300 Da, and whose IR
and NMR spectra are consistent with the structure indicated, with a ratio m/p=0.2.
E~AMPLE 2 Preoaration of a stabilizer corresPondin~ to the followina formula~

M(o3/2-si-)m~(o~ )p-~ ~ t CH (C~)3-C-CO-(c~2)2 Il .
C~2 t wherein M is H or C~3CH2-, M' is O~ or C~3C~20- and t 1 ter-butyl.

20.0 ml o~ ethanol, 11.91 g ~0.026 moles) of a co~pound having formula (III) wherein Rl ls methyl, R3 i~ ethyl and R7 , 2~7~7 is t 7~o ~ (CH2)2coo(cH2) O.50 y (0.0026 moles) of triethoxyvinylsilane and 3.0 ml o~
HzO are charged ~nto a flas~ equipped with stirrer, condenser and thermometer.
The solution is kept at 55~C until gaschromatographic analysis no longer reveals the presence of the reagents, i.e.
for about 5 hours. It is then left overnight at room temperature.
The ethanol is then removed by distillat~on, 0.04 ml of dibutyltindilaurate are added and the mixture is brought to a temperature of 100 to 130C at reduced pressure (up to 0.4 ~m Hg) for a period of 3 hours.
9.87 g of a resinous produ~t are obtained, whose IR and NMR spectra ar~ consistent wi~h the structure indica~ed, with a ratio m/p=0.1.
E~U~PLE 3 Pre~aration of t e same_s~abllizer as E~amDle 2 The same procedurP i~ n~ed a~ descr~b~d in Example ~, but charging 9.85 g of the com~ound ha~ing formula (III) and 1.10 g of trietho~yvinylsilane.
8.36 g of a re~inou~ product are obtai~ed, ~hos~
structure corIesponds t~ that of the product of E~ampl8 2, .

;, ~ , , , ;
,.. . . ..
' 2~77~2~

with a ratio m/p=0.2.

Preparation of the~same stabilizer as ExamDle 2.
The same procedure is used as described in Example 2, but charging 11,67 g of the compound hav~ng formula (III) and 4.93 g of triethoxyvinylsilane.
11.70 g of a resinous product are obtained, whos~
structure corresponds to that of the product of Example 2, with a ratio m/p=l.O.

Preparation of a stabi}izer correspond~nq to the followina formula:

~(o-Si-)p-~' t (I ~)3-0-C~-(C~ )2 ~ ~

wherein M is ~ or CH3CH2-, M' is 0~ or C~3C~20- and t is ter-b~tyl.
20.0 ml of ethanol, 5.0 ml of ~20 and 9.42 g of a compound havi~g for~ a ~III) wherein Rl i5 methyl, R3 is ethyl .. ._ ... . _ . .
and R~ is t ~ (C~2)2~00(C~)3-æ e charged Into a flask equipped wi~h a qtirrer, condenser and thermometer.

~ . . . .

2~7~2~

The solution is kep-t at 60C for about 2 hours. The ethanol is then removed by distillation, 0.02 ml of dibutyltindilaurate are added and the temperature is brought to 120C at reduced pressure (4 mm Hg) for a perlod of 3 hours.
8.21 g of a colo~rless resinous product are obtained, having an average osmometric molecular w~ight of about 1800 Da.

Pre~aration of a stabilizer correspondina to the follow~nq forsnula_ C~I
l'3 ~03/2-fi-, m~(o-si-)p-~- ~ CX3 CH (CH2)3 ~ r C~2 CH3 wherein M is ~ or CX3CH2-, and M' is OH or C~3C~20- .
20.0 ml of e~hianol, 6. a g ( o . 020 moles) o~ a compound having formula (III) wherein Rl is methyl, R~ ~ ethyl and R~

_ . . .
is C~3 ~I0~ (C~2) 3 ' .~,~
3.8 g (Oo2 moles) of trletho~y vi~yl~ilane and 3.0 ml of H20 are charged into a flask equipped with a stirrer, condanser.
and thermometer.

: . : . . , : ,,~ , 2~7~27 The solution is kept at room temperature until gaschromatographic analysi-~ no longer reveals the presenc~ of the reagents, i.e. for about 20 hours.
O.05 ml of dibutyltindilaurate S~re then added and the ethanol is slowly removed (4 hours) by distillat~on. ~he temperature ls brought to 120C at reduced pressure (u~ to 5 mm Hg) for a perlod of 3 hours.
6.53 g of a resinous prod-~ct are obtained, having an average osmometric molecular weight of 2500 Da, whose NMR
spectrum is con~istent with the structure indlcated, wlth a ratio m/p-lØ

Preparation of a stabilizer correspon~inq to the followin~

formula:
H3 :

~(O3/2-si-~m-(o-si-)p-M' t CN (CH2)3-O-CO ~ H

CX2 t wherein M is H dr CH3cH2-, M ~ is 0~ or CH3~0- and t is ter-butyl.
20.0 mi of ethanol, 5.60 g (O.013 ~oles) of a compound having formula (~II) wherein Rl i~ methyL, ~ is ethyl and R~

. _ . . .. .. .. _ . _ is t (c~2)3 t ~7~7 2.47 g (O. oi3 moles) of triethoxyvinylsilane and 3.0 ml of H20 are charged into a flask equlpped with a stirrer, ~o~denser and thermometer.
The same procedure is used as described in Eæample 2.
6086 g of a glass which can be broken into a solid white product , are obtained, whose IR and NMR spectra are consistent with the structure indicated, wlth a ratio m/p~.O.

Preparation o~ a stabilizer corresPondina tn the followinq formula:

~(03/2-si-)m-(o-si-)p-Nl t (I 2)3 (CH2)~-0-cO-(c~2)2 SH t wherein M is H or CH3C~2-, M' is OH or CH3CH20- and t is ter-butyl.
20.0 ml o~ ethanol, 7.98 g (0.017 moles) of a compound having formula (III) whereln ~ is methyl, R3 is ethyl and R6 ~s HO ~ (C~2~2COO(c~2)3-r 3.5 ml (O.017 moles) of 3-mercaptopropyltrimethoxysilane a~d 4.0 ml of H20 arQ charged into a flask eguipped wi~h a stirrer, condenser and the¢mometer.

, , .
, ' . ': . ~ ' ~

. .::

2~77927 The solution is kept at room tempera-ture until gaschromatographic analysis no longer reveals the presence of ~he reagents, i.e. for about lO hours.
The ethanol is then removed by distillation, and 50 ml of toluene and 0.02 ml of dibutyltindilaurate are added. The temperature is brought to 110C for a period of 3 hours while the water is azeotropically eliminated. The toluene is then removed by distillation and the residue is treated for 1 hour at 120C under vacuum.
9.35 g of a resinous product is obtained whose IR and NMR
spectra are consistent with the structure indicated, with a ratio m/p=lØ

Pre~aration of LDPE stabilized with the com~ounds of the invention.
Masters of commercial LDPE of the Riblene CF 2200 type with 10% by weight of stabilizer were prepared with the stabilizing compounds prepared as described in Examples 1,2,3,4 accor ing to the following procedure.
The stabilizing compound is dissolved in toluene; LDPE in powder form is added to this solution, and the solvent is then removed by evaporation at reduced pressure under stirring.
The masters t~us prepared are mixed with further commercial LDPE of ~he Riblene CF 2200 type to obtain mi~tures containing 0.2~ by weight of stabilizer~

~77~f~37 Each of these mixtures, to which 2,5-dimethyl-2,5-di(terbutylperoxy)hexane up to 0.015~ by weight has been added, is extruded ln a Brabender l.aboratory-~ype extruder with 50 rpm of the screw, and with the following temperature profile fro~ the head zone to the tail zone: 155-160-170-170C.
The samples thus eætruded are cut into pellets and pressed for 3 minutes at 200C, to obtain sample plates having a thickness of 0.5 mm.
Using the same procedure but without peroxide, LDPE
sample plates were prepared to which the compound of Comparative Example A, ANOg 20 or ANOX PP18 were added. The two latter products are. commercial additives containing the sterically hindered phenol group.
The sample plates thus prepared were extracted in soxhlet with acetone for 10 hours and with 1,2-dichloroethane for 7 hours.
The relative quantity of antioxidant remaining after the extraction treatment is evaluated on a first series of sample plates by IR measurements. The relative absorption variation is calculated at 1735 cm~~ compared with a non-stabilized sample (TQ), and the remaining percentage of antioxidant is expressed as:
Æ - A/Ao x 100 where Æ is the extraction resistance and Ao and A are the - 2~ -,: .
.. : .
~ ' , ~77~27 absorption values respectively before and after the extraction treatment. The results are shown in Table 1.
To verify the stabilization of theitest samples after the extraction treatment, a second series of sample plates was submitted to prolonged thermal treatment in an oven with air circulation at 100C. The degradation process was observed on the basis of the formation of carbonylic compounds revealed by IR measurements. In particular, the index valuei o~ car~onyl (ICo) is calculated, expressed as:
I~ ~ Al7lo~-l/Alsss~-l The induction time ls determined from the ICo values. A
greater effectiveness of the stabilizing action corresponds to a high value of the induction time. The induction times of the non-extracted (TIo) and extracted (TI) test samples are shown in Table II.
TABLE I
, ,. . . ~ ~ i ~ m/p R~
Example 1 O.2 63 Example 2 0.1 70 Example 3 0.2 77 Example 4 1.O 93 Example A (comparison) O S0 ANOX 20 / ~0 ANOX PP18 / ~ ~ r _ ~

.: : ~ : .

i, , .
' ~

2~77~27 TABLE II, . ~-- . ___ S A M P L E m/p~Io(h) TI (h) _ _ .___ _ __ TQ ~ . / 10 10 Ea:a~nple 1 0. 2 1650 920 Example ~ 0.1 1100 6~0 Example 3 O . 2 750 640 Example 4 1. O 630 500 Example A ( comp~rison ) O 1500 550 ANO~ PP18 i 1700 10 ' ___. ___ ~

. . .. . . .
.

: . . .,; . .-. .
- .: , . -~ . :

,~
'' ' . ' ,' ~ ', ' . . ~

Claims (17)

1. Polymeric stabilizers having the following formula:
MX2YpZqM' (I) wherein X = or Y = or Z = , or - O4/2Si -M = , H, R3, M ' = -OM , M and M' can optionally form together a direct bond thus producing a cyclic structure, R1 is a phenyl or a linear or branched alkyl radical containing from 1 to 20 carbon atoms, R2 is a reactive organic group capable of chemically binding itself to the polymeric structure to be stabilized, R3 is a linear or branched alkyl radical containing from 1 to 6 carbon atoms, R4 is a radical selected from the group including:

wherein, R5 and R6, the same or different, are alkyl radicals, linear or branched, containing from 1 to 10 carbon atoms, R7 is an alkylene radical, linear or branched, containing from 3 to 10 carbon atoms, R8 is an alkylene radical, linear or branched, containing from 1 to 10 carbon atoms, or a biradical selected from -R9-COO-R10,--R9-COO-R10-S-R11- and -R10-S-R11-, R9, R10 and R11, the same or different, are alkylene radicals, linear or branched, containing from 2 to 10 carbon atoms, R' is a phenyl or an alkyl radical, linear or branched, containing from 1 to 10 carbon atoms, R" is equal to R', R2 or R4, m, p, the same or different, are integers from 1 to 50, q is an integer between 0 and 50, n is equal to 0 or 1,

2. Polymeric stabilizers according to Claim 1, wherein R2 contains a carbon-carbon double bond, an epoxy ring, a sulphide group or an aminic group.

3. Polymeric stabilizers according to Claims 1 or 2, wherein R2 is a radical selected from the group including:

CH2=CH- HS-(CH2)3-H2N- (CH2)3-

4. Polymeric stabilizers according to any of the previous Claims, wherein R1 is a linear or branched alkyl radical containing from 1 to 10 carbon atoms.

5. Polymeric stabilizers according to any of the previous Claims, wherein R1 is a linear or branched alkyl radical containing from 1 to 3 carbon atoms.

6. Polymeric stabilizers according to any of the previous Claims, wherein R1 is methyl.

7. Polymeric stabilizers according to any of the previous Claims, wherein R5 and R6 are branched.

8. Polymeric stabilizers according to any of the previous Claims, wherein R5 and R6 are t-butyl radicals.

9. Polymeric stabilizers according to any of the previous Claims, wherein the monomeric units X, Y and Z have a random sequence.

10. Procedure for the preparation of the polymeric stabllizers according to Claims 1 to 9, including:
a) the reaction of a mixture of compounds having the formula:

(II) and of compounds having the formula:

(III) wherein R''' is OR3 or Cl, and R1, R2 and R4, n have the meaning previously defined, in water or in a mixture of organic solvent and water in ratios up to 10:1, at temperatures ranging from 20 to 100°C, for a period of 2-20 hours;
b) the subsequent polymerization reaction, for a period of 2-10 hours, carried out for the first period at the boiling point of the solvent, in the presence of a condensation catalyst, eliminating the reaction water and alcohol by distillation, and then at temperatures ranging from 60 to 140°C, at reduced pressure (0.1-50 mm Hg).

11. Procedure according to Claim 10, wherein the reaction of point a) is carried out in the presence of compounds having the formula:

(IV) and compounds having the formula:

(V) wherein r is equal to 0,1 or 2, and R1, R', R", R"', have the meaning previously defined.

12. Procedure according to Claims 10 or 11, wherein the organic solvent is selected from the group including ethers, alcohols, aliphatic, alicyclic or aromatic hydrocarbons.

13. Procedure according to Claims 10 to 12, wherein the condensation catalyst is selected from dibutyltin-dilaurate, zinc octanoate, tin octanoate or an alkaline hydroxide.

14. Procedure according to Claims 10 to 13, wherein the condensation catalyst is used in a concentration within the range of 0.005-0.5% by weight with respect to the reagents.

15. Polymeric compositions including an organic polymer and a stabilizing quantity of a polymeric stabilizer according to any of Claims 1 to 9.

16. Polymeric compositions according to Claim 15, wherein the organic polymer is selected from the group including LDPE, LLDPE and HDPE.

17. Polymeric compositions according to Claims 15 or 16, wherein, in the polymeric stabilizer, R1 is a methyl, R2 is CH2=CH-, CH2=C(CH3)-COO-(CH2)3- or HS-(CH2)3- and R4 is a radical having the formula: