FILMS AND OTHER PRODUCTS COPOLYMER COMPOSITIONS PREPARED THEREFROM. CONTROLLABLE DEGRADABILITY AND

Description

USTPIIA MODULARY. TRADE : handicrafts 17B YES. I − 48 TER MINISTRY OF TRADE AND CRAFT INDUSTRY DG Ρ. I. - CENTRAL PATENT OFFICE PATENT FOR INDUSTRIAL INVENTION No. 4 Π a ; ' τ ' …….; li pres-me patent is granted for the invention subject of the application below specified: ZA ΓΑ -'Ρ.ΕΞ CCMAMDA ·''·''·· ,; Μ 1 Η '.t η MILANO 1 13 7621^781 139 0 tj)C J ·_ = 3 3 6 N − = t τ £ r ».· « I _ ΐ 1 ? 0 Vi η η γ 2 3 IL J − 7Ρ A < Γ ? 1 J Γ I 4 Λ τ C Ρ ~ Λ Τ S Ρ A Ε L Ε rC'^OSITIONS Η CPPOLI^EP: Ί Ξ S ? 1 D Α 9 OR ?' Ί' 1')!) CCNTPOLATING THE Ε 3 Ε . L ISLAND Ε ALICE R Ρ 0 D 0 Τ τ I η ? > −> ft φ ·, τ ι ;SSE. Rome ί THE DIRECTOR Register To her Protocol no. 279.:9 A 78 and ; STERC OF THE R;* OF . Provincial Office of Industry, Trade and Crafts of Milan; i. ueiiuj: ni deposit pia: p,pu \ ì ì iii iris \ 1 \ / 1 >\i ι\ηι m ih u The:- 1975 twenty-one If you join the na;iar,; r;::: she.%·.. ;rea;ar.cve Gerald SCOTT 2) Dan GILEAD PLASTOPIL ItAZOREA ;c: seze arrese 2) and 3) the Italian 'J ί 3 ec e::: vare v : to: p-esSÓ '· I'm back Π £ is —? ù ' _ m| , Έ·|( — fR λ · r- −K 1) Knowle, Solihull( LARGE PROPERTY) 2) and 3) KIBBUTZ HAZOREA (ISRAEL) BARZAM)' (see ZA GOES to the DO SPA 2^1 exercise and 1 eq^e 3 Mi.ano - Goes to Burgonuovo I Ί — 3C ' Ϊ0 SC fi ΐ *0. c-sessicne There is a PATENT FOR STRIAL EXDI a.,n:e ter TITLE: Compositions of degradable copolymers in controllable knot and films and other products prepared from them PRIVATE? Al.E SweetBeet^jfc'»; ' ΓΧ XXXXX XX X sxx ISRAEL V. 51971 of 21 September PJCXXXK 1Ϊ xxxxxxxxxxxxxxx xxxx XXXXPZXX KX J — K 1 d* J 1 :ri E^ra. xsegr _ti:=ra ' ' 2 .tcd (temporary) - -χχχχχχχχχχιCoccren:; : and z-zone ι such that ι is (reserve) xxxxxxxxx xxx xxxxxxxxPr XXXXXPCXXX?<XXxXXXXXXXXXXXXXXXXXXÌCXZXXXXZCiXXXXXXXXZ> ZXlZX .You have z. c τ Air c, _. 'DO orrr. _ s wax r 668004 I < Ì FROM » rs 1=. - »4 · -3 answers ,9 .73 551 Pietro Messineo -V SA·· * _ i ρ, · 1 D Rector (Federico N 3 pu t. THE HEAD OF THE SEVENTH OFFICE (Dr. The ί 7 S 49 A / 78 SUBSCRIBE The Firm l) Gerald SCOTT 2) Dan GILEAD 3) PLASTOPIL HAZOREA -4, of nationals» χ ) English 2) and 3) Israeli domiciled with registered office at) Knowle, Solihull (GREAT BRITAIN) 2 and 3) KT33UTZ HAZOREA represented by Ing. BARZANO' 4 ZANARDO SpA in MILAN, Via Borgonuovo, ISRAEL 10, eoe domicile elected at the same, requests the granting of a patent PRINCIPAL for the invention entitled: 11 Compositions of controllably degradable polymers and films and other products prepared therefrom ι ; PRIORITY: The right of priority is claimed arising from the patent application in ISRAEL No. 52974 of 21 September 1977 Attached documentation: a) Description in duplicate of 38 pages of writing; (temporary) -b) Drawings in dp»he* vegeta of n. 2 tables; c) Letter of appointment; d) Priority document(s) with Italian translation; {reservation) e) A« ni di vers.to (on the C / C / P n.668004) of L. ^7 issued by the Ufi Post. . of Milan; f) Revenue stamp of L 2000 pp l) Gerald SCOTT 2) Dan GILEAD 3) PLASTOPIL HAZOREA Milan, September 1978 p. Ing. Barzapp & Zanardo Ap. A. 414 / 78 Eng. Barzanò & Zanardo DESCRIPTION of the industrial invention entitled: ·· · · Compositions of controllably degradable polymers and films and other products prepared from;,'·' ;··· • · • · · · · them ····! : . * · · · · · · · ;· « « « of Mr. Gerald SCOTT, of English nationality, resi-.; • * · · . *··· * Z tooth at Knovle, solihull (Great Britain), of the Signo» ··.'·· * · · · · * * · · · Dan GILEAD, an Israeli national residing in ·.·· F ♦·*·*· • · · · · · ea · · · KIBBUTZ HAZOREA (Israel) and the PLASTOPIL Company....; <··· HAZOREA, of Israeli nationality with headquarters in KIBBUTZ HAZOREA (Israel) deposited 21 <itf.1978 2 ? s 4 9 A / 79 TO It is known that substances which are degradation-promoting agents and which cause the degradation of the composition with the formation of preferably biodegradable oxidation products can be added to polymer compositions, generally vinyl polymers or copolymers, in particular polyolefins. The resulting compositions are useful, for example, as packaging materials which, after being used, will give rise to degradable waste products. Thus the description of the British patent No. 1.356*107 describes compositions of vinyl polymers containing a complex of a metal of Ing. Barzanò & Zanardo transition, preferably iron which is activated by a light having a wavelength shorter than 330 mm, an ultraviolet radiation. The complex-';·.· / Ί .tì so can be formed in situ by the so-called complexing agent and a salt of the metal. In the concentrations!!! * « · · · · :· * · · · · · extractions used the complex makes the composition ' .·'! ·· · · stable in the manufacturing process in which it is brought to the molten state, usually by extrusion or by extrusion by blowing....; • ··· 1 tion and during its use indoors, in particular as packaging material after which the material is discarded and exposed to sunlight which after a certain period of induction activates said metallic compound which then produces a relatively rapid degradation, no longer requiring exposure to ultraviolet radiation. While it is clear that the induction period can vary widely, there are no known means to precisely predetermine and control this induction period. It is suggested that antioxidants tend to increase the induction period, while an increase in the concentration of the activatable metal compound initially tends to decrease it, but after a certain time appears to increase it; the period can be controlled. Eng. Barzanò & Zanardo '7$ J f. induction by means of a suitable equilibrium concentration of a salt of a metal and a complexing agent or agent that retains the metal, however the results have not proved satisfactory for ·:.*·. * certain end-use applications. This is due to the fact that chp.;;; •V..; very small changes in concentration can produce very large changes in polymer lifetime. *”*' « · • a * · ♦ While with a ηοη····I • · *· · packaging material precise control is required since, in general, these packaging materials are not exposed to radiation of critical wavelength during their use, or at least can be easily protected from it so that their usual life will be as long as desired, this is not the case, for example, with a covering film where it is desired that the life time of the film can be controlled very precisely. In agriculture, crop protection or covering films are widely used. These films must perform their function, i.e. cover, envelop or protect the soil and / or the growing crops, in conditions which are <1*completely exposed outside, for - 4 - Eng· Barzanò & Zanardo ;J A.! ! a certain period of time or rather, from a certain time until another certain time of the— ·· ·· the year· Subsequently, certain agricultural operations must be carried out ··· • · · · such as plowing ·$.*ￂﾷ. harvesting of the crop, and the films constitute!!!! an obstacle to such operations & must be removed; • · · • · » · if· Except for some cases, in which the film can be used again and it is convenient to.** • · recover it, removal is an operation that requires....; • «·· · time consuming and expensive· With current formulations, one must use a polymer composition that will have an induction period as long as the time the film is exposed to sunlight, or longer, in which case removal of the film may still be necessary; or one must use a rapidly degradable composition that will degrade before its performance period has elapsed, in which case the film will not perform its protective function for the full period of time during which this is required. Furthermore, since the degree of effective UV radiation absorbed by the film will certainly depend on the location where the film is used, the season in which the film is applied and the period of exposure, and may depend - 5 - Ing· Barzanò & Zanardo from other factors (since the amount of information available in the sector from this point of view is scarce), it seemed impossible to define a type of.·.· / .'. ··· film that was able to adapt to the con—:.'·* * extremely varied geographical and agricultural conditions which; *· · they are in practice· • · · ·· ·· A film of a degradable polymer, a .· ·' *···* * Once it has been exposed to UV radiation, it will go through a number of stages of degradation.' 1. r 1 I :t , .1 tion, including a stage called embrittlement in which the film maintains its shape and continuity and therefore its protective character, substantially unchanged, but in which it will be easily broken by the mechanical action of a tilling or cultivating tool., for example a plough or a harrow or a cultivator. The embrittlement stage is characterised by an elongation at break that is substantially zero. For a given geographical location and for a given season of application of the film, the time required to reach the embrittlement stage, i.e. the embrittlement time* is a function of the total amount of UV radiation to which the film has been exposed, so that, for practical purposes, all other factors can be neglected and it is possible to determine, in advance, based on simple experimental tests, the time at which the film, while still embrittled;. once it has completely fulfilled its protective function, it has reached the stage at which it can be eliminated by working the soil in a usual way. And 9 9 ·*· • * V · * The Applicant has found, surprisingly, according to the present invention, that the time required to reach embrittlement can be predetermined and can be varied at will. rt ,'lj A with remarkable precision, especially in polyolefin films, by ensuring that the product contains carefully controlled quantities of a metal, for example iron, a complex of the type described in the above British patent in combination with a UV stabilizing complex, for example a nickel complex. This is quite surprising, since iron compounds alone and nickel compounds alone, while both influence the embrittlement time, do not allow the latter to be precisely controlled and predicted, so that an inexplicable synergistic effect occurs between Eng. Barzanò & Zanardo I i ι - 7 the two types of complex of a metal which is not simply quantitative, as are invariably the synergistic effects, but is qualitative, dan-Λ*.'.*. « · » · · *** I do not simply result in an exaltation'··:. of a certain property, but a complete change in behavior. .... * · · · · ' Because of this, while the word synergistic” * ·. • · · · will be used for lack of a better word, yes ., · • 0 must be understood to mean that it does not, in fact, describe ·*··Ζ • · · · · the phenomenon, which is much more fundamental and unusual than the word might suggest· The individual functions of the two types of metal complex represented by the iron complexes indicated in the above British patent application and those exemplified by the nickel complex which may be a complex of the same ligand, differ in that the former are potent activators of ultraviolet degradation of a variety of polymers, after a relatively short induction period, while the latter are stabilizing agents against ultraviolet rays; they have a relatively long induction period before ultraviolet-induced degradation begins and the subsequent rate of photodegradation is very slow. This difference in • · 0 0 0 .· j·· 0 0 0* - 8 - ing· Barzanò & zanardo behavior, in turn, is associated with the instability towards ultraviolet rays of the former and with the stability towards ultraviolet rays of the latter. According to this invention, a;;;;; composition of a vinyl polymer comprising ·· · · at least one soluble antioxidant complex in sol- .· ·* a aaaa ··. non-ionic organic winds of a compound that breaks the i .! Ί ···· • « ··· »« · the chain, which decomposes the peroxides, which deactivates?···: • · ·· · metal ions, or which stabilize against ultraviolet light and a metal, e.g. iron, manganese or cerium which, in combination with the compound, forms a photoactivator and at least one ultraviolet-stabilizing complex, soluble in non-ionic organic solvents, of a metal, e.g. nickel, cobalt or copper, such that the metal complex is a photostabilizer, the concentrations of the two metal complexes being coordinated to produce the desired embrittlement time. The compositions of the present invention are particularly useful for the production of films, particularly overlay films, but it is intended that the compositions of the present invention may also be used for a variety of purposes. - 9 - Eng. Barzanò & Zanardo in the packaging sector In the case of a covering film, it is understood that, after the embrittlement stage has been reached, if the film is left it remains!^ 1· a • a · aa on the ground and is not interfered with,JpZI ·· its degradation will proceed and eventually we will have upa;· a disintegration In some cases it may be desirable to operate in this way. Thus, it is not necessary for the soil to be worked at the '**'; time at which the embrittlement stage of the film has been reached or immediately thereafter, but only after degradation has proceeded, possibly to substantially complete disintegration of the film. According to the present invention, a process is also provided which consists of applying a protective film or a covering film of the present invention to an agricultural area, allowing it to settle on the area, for example a field, at least until it has reached the embrittlement stage. and then remove it from the soil surface during a traditional tillage operation. Using the compositions of the present invention, it is possible to create a film that will maintain its physical continuity and, subsequently, 10 - Ing. Barzanò & zanardo τ You f the -.1 mind, it will exercise its protective activity for the entire desired period of time, and not only not a··· • will interfere with subsequent operations, for example a ploughing, but, in fact, it will be eliminated from that—!. aaa · aa the operations without the need for ef-iZZZZ a* « make any changes in them..«· *··!* a The process of the present invention may also be used for the production of fibres, nets and twines having a carefully controlled shelf life from fibre-forming polymers, in particular from high density polyethylene, polypropylene and blends and copolymers of these and from polyamides and polyesters. Vinyl polymers are homopolymers or copolymers that form fibres, in particular polyolefins, and more particularly polyethylene, of high density and low density, and also polypropylene. Other vinyl polymers include poly(4-methyl-1-pentane), polystyrene, polyvinyl acetate, polyvinyl chloride, polymethyl methacrylate and polyacrylonitrile and their copolymers including graft copolymers with unsaturated polymers, and also mixtures of such polymers, in particular with unsaturated polymers. In the case of polypropylene in the form of fibres • and · ·.··. ♦ * · - 11 - Eng. Barzanò & Zanardo .Ϊ or films, in particular, it has been found that it is possible to accurately control the shelf life of the product starting from a small proportion .····. ·· · · of its normal duration (for example without ·*···· ​​***'! UV activators or without stabilizing agents. UV) >e4>Ì « · · · 0 up to more than five times the normal duration · / ... and have a very sharp change from a hard and strong product to a brittle and fragile product in cor—*'. 0 0 0 · ·· * compliance with the end of the desired duration · Setter and preferred additives, which may be present, are thermal antioxidants and normally provide stability during processing, traditional antioxidants such as 1,1,2-tris-4-(2-tert.butyl-4-hydroxy-5-methyl)-phenylpropane may be used to provide additional stability during film-forming or fiber-forming operations. The film forming technique, for example extrusion, in particular tubular blowing extrusion, however, is conventional and does not form part of the present invention. The antioxidant itself plays no role in determining the embrittlement time and is therefore used in traditional quantities. If desired, - 12 - Eng. Barzanò & Zanardo Uh|ff can also add inert pigments, colorants and other traditional additives to the polymer. In general, pigments act as filtering agents for ultraviolet rays and increase the iri·** / .' ···· embrittlement of the polymer. This is particularly true: ** ·« · and « • · · · A ·, in the case of carbon black, but a variety of white pigments or photo-colored pigments can be used successfully; .· · Favorite combinations use fér— complexes; • AA · · nickel and the following discussion will refer, for convenience, to these metals. However, it is understood that exactly analogous considerations apply to the other complexes. The concentration of the iron complex is generally between 0.0005% and 0.5% by weight (5 - 5000 t ppm), preferably between 0.0005% or 0.001% to 0.2% by weight, and more specifically, it is between 0.01% and 0.05% by weight. The concentration of the nickel complex generally is between 0.0005% or 0.001% and 0.2% or 0.5% by weight, for example it is between 0.01% and 0.15% or between 0.05% and 0.5%, preferably it is between 0.1% and 0.2% by weight. Naturally, the weight of the complexing agent will affect the metal concentration, which is the controlling factor; the numbers given above in par- 13 Ing· Barzanò & Zanardo ΐ-I s ir specicolare refers to di-alkyl-di-thio-carbamates such as dibutyl-di-thio-carbamate. The relative concentrations to be adopted of the two .·'··. ··.· metal complexes depend largely on the use ·*··;; ···:. for which the finished article is intended. In general*...· *** * · · by increasing the concentration of the complex of the*... and »·** * \ · · iron a more complete induction period is obtained*·; • · * * (during which the stabilization is increased-. .· · ta) and a more marked change is obtained from the sta^i·· ····: degradation. The effect of the nickel complex is to increase the full induction period so that it can be shorter or, if desired, longer than the natural lifetime of the polymer. Of course, a sharp or sudden change in the behavior of the combination is particularly important when producing a coating film, since for this particular application, the lifetime <5 is known at which the film is required, at the end of which time it is desired to dispose of it as easily as possible. In general, a high nickel concentration, combined with a low or medium iron concentration, will achieve a long induction period, • ftft • · 4 -the ' 4 ' Ϊ Xi j ί i — 14 — Eng. Barzanò & Zanardo followed by a rapid photo-oxidation. These considerations should be made in the case in which the culture takes place after a relatively long period, for example after 6-9 months. With a high concentration of iron and with a low concentration of nickel, there is a short period of inductions. but there is a very clear change in the behaviour. , ; .... • · » · · at the end of this period of ***** ***** ···· • * · · · · induction· It is understood that the lower the concfarfr. ····, the traction of the nickel complex, the shorter the induction period becomes and, consequently, small changes in the iron concentration have a significant impact on the stability of the product. The total amount of irradiation to which a unit area of ​​film is exposed until embrittlement occurs provides a good definition of the film's behavior. Different periods of time may correspond to the same amount of total irradiation, depending on the geographic location and the season. While such periods will also be indicated in terms of days below, it is obvious that the total amount of irradiation is a more appropriate or more significant parameter. The total amounts of irradiation Ing· Barzanò & zanardo indicated below refer to a radiation of wavelength less than 3150 Angstrom, ·· · · and there is no differentiation or it is not necessary to make any differentiation between a*·* '··!· · • global, direct, and diffuse UV irradiation A useful general discussion of the topic of UV irradiation can be found in J. Appi. Poi. Se, Vol. 20, , . ;.·.: '· »· · · ·* 1165-1174 (1976). ....Z * / ;; .« · · ·. · • · · * · In order to better describe the cornbi^* effect! « · · · born of metal concentrations in the compositions, we now refer to the figures in the attached drawings, in which: Fig. 1 is a diagram illustrating the effect of a carabiner on the concentration of the iron compound, specifically iron dimethyl dithiocarbamate, for a given constant concentration of the nickel compound, specifically nickel dibutyl dithiocarbamate, the abscissa being the total amount of irradiation required for the film to reach the embrittlement stage (in raVx min / cm2), and the ordinate being proportional to the logarithm of the concentration (in parts per million) of the iron compound; and Fig. 2 is a similar diagram illustrating the effect of varying concentrations of the nickel compound. ￃﾬ; ' L '.ￎﾝ ￎﾊￎﾓ * The' - 16 - Engￂﾷ Barzanò & Zanardo nickel at constant concentrations of the iron compound, where, however, the ordinate is proportional to the actual concentration .····. ···** of the nickel compound· ··; •ϊ · ···· The irradiation, in all cases, is expressed ee · · · ·.·.··· as microwatts x min / cm , and the concentrations are expressed as ipm. ··; • and • · * ee * Referring to fig· 1, the concentration of. e<>; .. · nickel compound choice is 1000 ppm; however, the····; • *ee # The general shape of the curves does not change if another concentration of the nickel compound is chosen. Curve A concerns a film that was deposited on January 1st and curve B concerns a film that was deposited on September 22nd, both at latitude 32° North. The films were unprotected from light: obviously, if they had been protected from light by existing vegetation or growing crops, they would have required a longer time to receive the same amount of irradiation. It can be seen that the curves are approximately hyperbolic in shape. Below iron compound concentrations of 5-10 ppm, this metal is practically ineffective and the curves approach the horizontal. Above a certain limit, about 1000 ppm. ·.··* - 17 - Eng. Barzanò & Zanardo $ ￎﾹThe increased concentrations are ineffective and the curve becomes vertical. Between these maximum concentrations and these minimum concentrations, the effect of a can-.·'**. ·· · · • ·· variation in the concentration of a compound of iron*^“ I · ···. ro is very marked and very precise. This change ....· ««•00 • 0 0 0 0 ·· is called the control interval here».. ♦ ··· • · lo; concentrations above the range of *'·; « 0 0 0 , ·« « · controls can be adopted, but they are wasted te<>; .· · Furthermore it can be seen that, while the date of application—·; ' ····. film temperature has an influence on the embrittlement irradiation, i.e. on the amount of irradiation at which embrittlement occurs, i.e. on the abscissa of the diagram, as one would expect since other schematic factors are involved, it has no effect on the shape of the curve and, therefore, once the behaviour of a film is known at any given iron concentration for a given season, it is known, or can be extrapolated, referring to any given concentration. Fig. 2 shows the behavior of films having varying nickel compound concentrations and having two fixed iron compound concentrations - 50 ppm for the solid line curves and «00 «·« · «00 0 .· 0« - 18 - Eng. Barzanò & Zanardo 100 ppm for the dashed curves, for two film application dates: March and August. Referring, first, to the application date of the.*. * * * From the March film it can be seen that when the concentration of the iron compound is 50 ppm, concentrations of the nickel compound exceeding 1500 ppm do not affect the embrittlement radiation, i.e. the curve is vertical. Between approximately 1500 and 1000 ppm, the embrittlement radiation increases significantly with the nickel concentration: this represents, X therefore, the nickel control range. Below the control range, the curve becomes vertical again. The March curve, which refers to the iron compound concentration of 100 ppm, has a similar shape, but the control range is at lower nickel concentrations. Between 500 ppm and 1000 ppm, the two March curves overlap, although in the figure they have been drawn side by side for clarity. As the film application season moves towards August, the embrittlement irradiations decrease and the concentrations of the compound / Nickel levels from a low value like 100 up to a high value like 2000 ppm no longer have any influence. - 19 — Eng. Barzanò & Zanardo 1. *» '4 significant influence on the embrittlement irradiation. The curves become completely vertical. In appearance, there is no control interval. However, it is believed that the control interval is!! *:. control can be moved down towards—;;· •^A · · At lower nickel contractions, so low that the ejV»·: • · · · · infected are difficult to detect, and are not useful. .· • A • AA since any irradiation of in»-»· can be obtained.! .. · « · lowest desired fragility, within certain limits!! •... * increasing the iron concentration, as shown in figure 1 · It is believed that this phenomenon may perhaps explain why the existence of control intervals has not been discovered previously. It should be noted that even when the nickel compound concentrations are not in the nickel control range, i.e. when operating in the areas of the straight lines in Figure 2, a change in the nickel compound concentration is not irrelevant since it affects the iron compound control range, i.e. leads to a shift of the curves of the type in Figure 1. Therefore, it is not necessary to operate in the control ranges of both metals; clearly, however, it is desirable to operate under conditions in which at least one of the two nickel compounds is in the control range of both metals; AAA A · • · AA « I ; .· / •J Γ μ· -fi - 20 - Eng. Barzanò & Zanardo metals have concentrations within the controlled range corresponding to the indicated concentration of the other compound. This is an unexpected and surprising phenomenon; this phenomenon constitutes a '!· ;... *** · · « * aspect of the qualitative synergistic relationship between the;;;;· ·”' ··*·· * · · J· ♦ two metals· ····· .... .··· · ·· • * · · The concentration and range data of , *· J.·.; • · · · * • ·· · · .· concentrations which have been indicated here and which will be indicated here, are substantially valid for****: * · · · · Φ • ··· · all metal complexes that can be used. Practically, such compounds will be stable under the processing conditions, will have a low volatility and will be reasonably accessible and not too expensive. The quantitative data given here can be transferred from one compound to another compound, in particular in relation to alkyl-thio-carbamates, by means of simple stoichiometric calculations, which allow to reproduce, with different compounds, substantially the same concentrations of metals. The preferred iron, manganese and cerium complexes used in the compositions of the present invention may be any of the antioxidant complexes cited in the above-mentioned UK patent application. Thus, the ligand atoms, for example, may be nitrogen, sulfur, oxygen or phosphorus, particularly trivalent phosphorus, sulfur being preferred. In general, the ligand atoms of the complex are oxygen, nitrogen or sulfur, with at least one being nitrogen or sulfur, or an oxy- VX! h gene directly linked to an aryl radical. Trà”i; 0^*· 0 « Examples of suitable complexing agents include monoamines and polyamines, in particular aminoacids, oximes, alcohols, thiols, phenols, thiophenols, esters and *'“* 0 0 amides of phosphoric acid, phosphamic acid and phosphorous acid and their thio-analogues, ketones, thio-ketones and amides and their thio-analogues, hydrazines, hydrazones, Schiff bases and azo compounds. Metal complexes of the following complexing agents (which, however, do not necessarily exist in the free state) are generally preferred for use in the compositions of this invention: 0« 0 0 « 0 « 00 (i) nc-sh (dithiocarbesumates) f RO S \ll ^P-SH (dithiophosphates), RgO ROC-SH ( x'antati ), l, S i KI / .NCN / \ - 22 - Eng. Barzanò & Zanardo 4' ΐ' · wherein R, R 1 , Rg , R^ and each represent a hydrogen or an alkyl, arylalkyl or aryl group or represent a group to which A,..* legacies among the 1$** .V... ro to form, with an indicated nitrogen atom, a ;   . heterocyclic ring such as di-isopropyl-ti£ ,· * ·“ 9 *99· phosphoryl-monosulfide, di-isopropyl-thio-phosphoryl-diesel··· ΓΪ · • · Pure# trimethyl-thiourea and thio-urea-disolfwjjy tetrameters'· ···· · II (ii) HS.CS-NR 5-N-CS.SH O. s II HS-P-OR 5O-P-SH OR, OR, * 9 9 9 9 9 *r. 9 9 '5 d where R^ is hydrogen or an alkyl, arylalkyl or aryl group, or is a substituted alkyl, substituted arylalkyl or substituted aryl group, and is a divalent aliphatic radical, e.g. alkylene, an aromatic radical, e.g. phenylene, or a heterocyclic radical which may be polymeric: - Ing· Barzanò & zanardo ri N (benaothiazolà.)* ì'“ ···«· · · f • MI* · * * where R· represents a substituted alkyl, hydroxyl or chlorine group, or represents an alkylene radical that bonds two such aromatic groups, R represents hydrogen, or *··*; '·* · « « · 4 represents an alkyl or aryl group or represents a substituted alkyl or aryl group, r represents a hydroxyl, alkoxy, alkyl or substituted alkyl group including an ethylene bridge or a propylene bridge linking two such aromatic groups such as salicylylaldehyde, di(salicylidene)-ethylene diamine, 4-methyl-2-hydroxy-acetophenone oxime, mercaptobenzothiazole and mercaptobenzimidazole; (iv) aromatic amines, traditionally used as antioxidants and as metal retaining agents, having the formula: aryl-NH-aryl, in particular when the aryl groups are, in turn, substituted, for example by hydroxyl groups, by amino groups and by substituted amino groups; (v) substituted phenols and, in particular, phenols - 24 - Ing· Barzanò & Zanardo multifunctional formula: 7 8 9 where R and R z are alkyl groups and R and R are hydrogen or alkyl substituted with complexing groups such as hydroxyphenyl. Typical phenols in this class include: 2,2-methylene)bis[4-methyl-<>-(1-methylcyclohexyl)phenol7, 1,1,2-tri-4(2-tert,butyl-5-methyl)phenyl-propane" tetra- / 4-( 2,6 -di-tert · butyl ) phenyl-ethyl arboni los s imeti l7 -methane, 4"4'-thio-bis(2-tert.butyl-4-*aethyl)phenol and 2,2 »-t io-bis (4*Hnetyl-6-tert. butyl )phenol, and (vi) cyclic phosphates of the type: including their substituted derivatives Dithiocarbamates are particularly preferred because they are essentially non-toxic. In the complexing agents mentioned above, one pre- 25 — Ing. Barzanò & Zanardo AND.· § ί* ili / ì ' 1 7.4 provided that the alkyl group or the chenyl group contains no more than 6 and preferably no more than 4 carbon atoms, it is preferred that the aryl groups be phenyl and it is preferred that the substituents, when present in these groups, are preferably halogens such as for example dorai.. ** ..·:* ·**' a c -C- alkoxy group or a hydroxy group or an amino group. Such complexes *”*. ΖL*. ***** ·.·· ·· * · · · can be preformed before ZZ are added. • · ·· Φ to the thermoplastic polymer, or they may be produced in situ by reacting an organo-soluble metal salt as previously indicated, for example, a carboxylate, for example a stearate, with a complexing agent that has already been added to the polymer. The complexing agent may be the UV-stabilizing additive in which the stabilizing metal ion (e.g. Ni) is partially displaced in the complex by the activating ion (e.g. Fe) by a metathesis reaction that gives a relatively inert salt of the displaced metal (Ni). It is desirable to add the metal-retaining agent first, since otherwise some degradation occurs during processing, which, of course, gives rise to complications. Ing· Barzanò & Zanardo t' r :'l THE" W 4 Ni t Preferred nickel complexes are generally derived from the same ligands as iron complexes, for example, from di-tio-carboxylates, di-Λ'. • · · -thiophosphates, xanthates, oximes, benzothiazoles, phenols*·.· • I · ·· 00 and compounds similar to those mentioned above in relation...: 0 0 0 0 ;· with iron complexes and can also come ····; ···* • 0 complexed with further coordination ligands • · *· · · (for example amines)· It is understood that the majority.,..; .. · of the complexes that break the nickel chain, which ····; 00 φ « « 0 0 · decompose peroxides and deactivate metal ions are also ultraviolet-stabilizing complexes. However, the ligand for iron need not be the same as the ligand for nickel in any combination. Again, dithiocarbamates are particularly preferred as ligands for both metals. The complexes (or an organic solvent-soluble form of the metal ion together with the complexing agent) can be introduced into the polymer in a known manner, for example, by mixing, kneading or milling. The thermoplastic compositions of the present invention may contain other composition ingredients, for example blowing agents. «0« 0 0 0 0 • « « «00 THE -ί +it You Ί ?,ί c I t; '•aj i 'ii 'l' Iti •i J -THE Ί l .l - 27 - Eng. Barzanò & Zanardo antioxidants, stabilizers, lubricants, antistatic agents and anti-blocking agents and also polyconjugated dyes soluble in polymers such as for example / **1 .·· β-carotene and azo dyes that are sensitive to β116ζ!! chemical conditions that prevail in correspondence with...: AAAAA aaaaa ;· of the beginning of a rapid disintegration of the polymer^ It should also be noted that, operating under conditions AAAA • AA · of field, a certain dispersion of ... can be found; .· · AA results are due to random factors and can be found**··; ..... some occasionally anomalous results. The curves in Figures 1 and 2 have been drawn, wherever necessary, by interpolation, but this has been required in surprisingly few cases, the results being much more important than might have been expected from the true nature of the tests. The following examples further illustrate AAA AAA AAA ·.··. the present invention EXAMPLE 1 The polymer used as the base for the films in the embodiments is a low density polyethylene having a melt flow rate of 0.7-1.0 g per 10 minutes at 2160 kg and 190°C. The polymer contained 250-300 ppm of a heat-stabilizing agent known in the art as BHT. :·ί rr 'il· Λ : 'ί - 28 - Eng. Barzanò & Zanardo The compound used was iron dimethyl-dithiocarbamate and the nickel compound was nickel dibutyl-dithiocarbamate. They were added to the poly-. ·· · · • · * I introduce them into mother mixtures having concentration—··;;; ft* « ·· ft. tractions 5% - 0.5% by weight and mixing the mixtures-,.,.; •Mi « ft · -mothers with the base polymer in the flake state., ·· ·;* or in the molten state, the e- **· technique was adopted; • ft ft · • ftft· extrusion of tubular blown films, which is • · * traditional in the processing of polyethylene · Lei*:*; Maximum processing temperatures were in the order of 210°C. The film thickness was 30 microns; however, tests with greater thicknesses, up to the maximum practical thickness of 100 microns, indicated that the material behavior was substantially the same for all thicknesses in that range. The films were then applied in the field, with complete exposure to irradiation. The following tables summarize the results of the various embodiments. Table I illustrates the behavior of films applied on September 22 at a latitude of 32° North. Column i indicates the sample number; column II indicates the concentration of iron dimethyl-di-thiocarbamate (trivalent), 1^1• · * · · ··. • · · :·· • ftft »·· « · • · · Ing. Barzanò & Zanardo three metallic component being nickel dibutyl-di—thio—carbamate with a constant concentration of .··· • · ·· ♦ · 1000 ppm; column III indicates the irradiance of · / ·.·· ♦ · · · · infr agii intent in mWxmin / cmq, and column IV iridi··; the actual duration of exposure in days. *,··'· * · Table II is similar to Table I but regurgg>*;· ···· from films applied on January 1st (at the same latitude). / ·. * » Table III shows the behavior of films having varying concentrations of iron compounds and nickel compounds (which compounds are the same as those in the previous tables). In Table III, column II is divided into two parts, column IIa indicates the concentration of the iron compound and column IIb indicates the concentration of the nickel compound. The films were applied on August 26 (at the same latitude). Table IV is similar to Table III but concerns films applied on March 1st (at the same latitude). •f txl' '·. 1 . -f TABLE I Eng. Barzanò & Zanardo I II III IV 1 5 3000 218 2 10 1920 182 3 50 1300 129 4 100 1300 129 5 500 1040 59 6 1000 1040 59 7 2000 1040 59 8 3000 1040 59 TABLE II I_II_III___IV 1 10 4300 180 2 25 4300 180 3 50 2600 160 4 100 2000 125 5 500 1700 108 6 1000 1700 108 7 2000 1700 108 8 s 3000 1700 108 »4 · · · 4 4 4 4 4*444 .··* *44« Eng. Barzanò & Zanardo TABLE III I Ila Ilb ITI *.·.Γν I 50 100 1950 '···' .... ·! · ··· · 2 50 500 1950 3 50 1000 1950 •···· · a · :· ni··· ····· ··. 4 50 1500 1950 · 5 50 2000 1950 6 100 100 1780 .. «ί··*· • · 9 9·· 7 100 500 1815 ““ ·· t * 4 β 100 1000 1815 71 9 100 1500 1815 71 10 100 2000 1815 71 T TABLE IV III IV Ila Ilb 1 50 100 2340 86 2 50 500 2340 . 86 3 50 1000 2340 86 4 50 1500 2900 103 5 50 20 00 2900 103 6 100 100 1740 77 7 100 500 2340 86 8 100 1000 2340 86 9 100 1500 2340 86 10 100 2000 2340 86 Eng. Barzanò & Zanardo EXAMPLE 2 rt ;.to S High density polyethylene (density 0.96 * · · • · *0 « · MFI 0.5) containing BHT (400 ppm) and distearyl-dithio-.·.·. • · · · · NiDBC (600 ppm) were mixed with NiDBC*·: with • 0 0 0 0 (1000 ppm) and / FeDMDC (ferrous metal dimethyl dithiocarbamate) (variable). The films were blown at 200°C to a thickness of between 10 microns and 50 microns. The samples were exposed to ultraviolet light (combination of a sun lamp and a black lamp) to simulate ultraviolet light. 0«0 « 0 ' ·.· « 0 ··' « solar and the times needed for the resistance to ii b you're tear is reduced to such an extent that the films tear like tissue paper are indif-V r tri cati in the tì>ella that follows· FeDMDC concentration (ppm) Time for complete loss of tear strength (hours) AND: •rr? 1 50 1170 2. 100 630 3 200 450 4 300 390 5 400 300 6 500 280 7. 1000 330 8 2000 550 Ί j j Parallel results were obtained when identical films were exposed, outdoors, in England starting in April. 300 hours — 33 — Eng. Barzanò & Zanardo in the above table correspond to about 60 summer days. .... • * ·· · · This process was repeated except that sV··** .... • « · · · * « ··· * .· . ···· the concentration of FeDMDC is kept constant at *; * « · · · · • · · · · « 100 ppm and the concentration of the ·.·.··· ·.·.· *”*; ···, NiDBC. The times to obtain embrittlement are ·· . ···; · . · • . ···· indicated in the following table· .*·.·* Ni DBC concentration (ppm) Time to .··. loss of tear strength (hours) 1. 50 75 2· 100 125 3« 500 445 4· 1000 655 5· 2000 1215 6· 3000 1550 EXAMPLE 3 Unstabilized polypropylene was mixed with FeDMDC and NiDBC in a small mixer at 180°C for 2 minutes and was compression molded into a film 0.005 in. (0.127 mm) thick. The films were irradiated with ultraviolet light as described in Example 2, and the time to embrittlement was measured. The results are shown in the following table. — 34 — Eng. Barzanò & Zanardo NiDBC (ppm) 0 1000 2000 3000 4000 FeDMDC (ppm) Embrittlement time ·· ·· 100 116 956 1515 225Ο···'®516 A*A AAA * * * 250 137 619 956 A * 174Ο*··5$2$ￎﾟ EXAMPLE 4 ￂﾷￂﾷￂﾷￂﾷ: ￂﾷￂﾷ.. .ￂﾷￂﾷￂﾷ .··* » · · · The above example was repeated but using ! · ·· ······ • · AA · ···· * · commercial grade stabilized polypropylene (cont^; ···· «· · ·**· · AA · · * A nente a synergistic thermo-stabilizing agent co- ····; ····· (constituted by Irganox 1076 / dilauryl-thio-dipropionate) and the results are shown in the following table. NiDBC (ppm) 0 1000 2000 3000 4000 FeDMDC (ppm) Embrittlement Time 100 *116 >51 1072 1410 1740 250 256 404 788 1072 1515 Comparing Examples 3 and 4 it can be seen that oils for maximum induction periods before the onset of rapid degradation, unstabilized polypropylene should be used. EXAMPLE 5 » LDPE was processed at 160°C under the conditions of Example 3 and compression molded to a 0.005 inch (0.127 mm) thick film with different concentrations of iron dibutyl dithiocarbamate (FeDBC) and cobalt dibutyl dithiocarbamate (CoDBC). Embrittlement times are given. in the following table. ···· • Σ · ·· ·· e • FeDBC (ppm) CODBC (ppm) • · · e · Time of infringement limerò· (hours) ···'··; 100 100 719 ···· 100 1000 1719 e « • · • · ·· 500 100 692 .. · 500 1000 1145 . • · • • ···* • · · · · 'J

Claims

1. CLAIMS 1. A composition comprising a vinyl polymer and at least a first complex which is an organic solvent-soluble, non-ionic antioxidant complex of a chain-breaking, peroxide-decomposing, metal ion-deactivating, or ultraviolet light-stabilizing compound and of a metal such that the metal complex is a photoactivator, and at least a second complex which is an organic solvent-soluble, non-ionic ultraviolet light-stabilizing complex of a metal such that the metal complex is a photostabilizer, the concentrations of the two complexes being coordinated to achieve a desired embrittlement time for the composition. - 36 - Ing. Barzanò & zanardo 2. Composition according to claim 1 wherein the first complex is a complex of iron · ·* · •ft · · 3. Composition according to claim 1 or claim 2 wherein the second complex is a nickel complex or a cobalt complex 4. a composition according to any of claims 1 to 3 in which the concentrations of the complexes are such that the concentration of at least one complex is in a control range (as defined herein). 5· Composition according to any of claims 1 to 4 containing 0.0005% up to * 0.5% by weight of said first complex and 0.01% up to 0.5% by weight of said second complex· 6· Composition according to claim 5 which contains 0.001% - 0.05% by weight of said first complex and 0.1^),2% by weight of said second complex.

7. Composition according to any of the preceding claims wherein at least one of the complexes is derived from a di-thiocarbamate, di-thiophosphate, xanthate, cyclic phosphate, oxime, benzothiazole or benzimidazole.

8. Composiziae according to claim 7 wherein the first complex and the second complex are derived from an alkyl-di-thio-carbamate. • ft ftft • ftft - 37 - Ing Barzanò & Zanardo 9· Composition according to any of the preceding claims comprising a stabilizing agent*· ·· • · ·· · * antioxidant· ***** 4 444 4 ·· *·* 10. Composition according to claim 1 substantially as previously described herein. 11· Film obtained from a common composition claimed in any of the claims 1 to 10.

12. Film according to claim 11 which is a protective film or a covering film. ÌfJ ,V 4 4 4 :: ► ·· 4 4 • 44 13· Film according to claim 11 or 12 which has a thickness between 30 microns and 100 microns· 1ϊ i* 14. Film according to claim 11, substantially as previously described herein.

15. An agricultural process comprising applying a protective film or covering film, as claimed in any one of claims 12 to 14, to an area of ​​land on which a crop is growing, leaving the film deposited in the area at least until it has reached its intended stage of infringement, and thereafter carrying out soil tillage operations in said area substantially so as to remove the film from the surface of the land. 16· Process according to claim 15 ···· • « ···· in which the soil working operations *.·.·.* * .· ·;· are carried out when the film which has undergone**·; * • « Φ · « the embrittlement is still substantially continuous, ·.· / ·· whereby said film is broken· .·*:* *·< ♦ 17· Process according to claim 15 in which the soil working operations are not carried out before the film has been broken· • 3 Γ jrì. p· Ing· Barzanò & Zanardo 3256 / cOR / vr /