WO2011065855A1

WO2011065855A1 - "biocompostable polymer blends"

Info

Publication number: WO2011065855A1
Application number: PCT/PT2010/000051
Authority: WO
Inventors: Rita Alexandra Meneses; João Francisco COUTINHO; António Alexandre SOARES
Original assignee: Cabopol - Indústria De Compostos, S.A.
Priority date: 2009-11-26
Filing date: 2010-11-25
Publication date: 2011-06-03
Also published as: PT104846A

Abstract

The objective of the present invention is to provide compositions of biocompostable resins and its processed product where the composition of biocompostable resins shows excellent biodegradability and mechanical resistance and, moreover, it is economically accessible, easy to process and usable in a wide range of applications. Considering the demand for the above mentioned characteristics, the inventors have committed themselves to their study and optimization. As a result, the inventors discovered that the injectability and processability of the biocompostable compound improved considerably, and that the compatibility and dispersibility between the continuous and discontinuous phases were excellent, due to the fact that the polyester/native starch blends were additivated with a compatibilizer, a dispersant and a polyester plasticizer.This way, a biocompostable blend, according with this invention, comprises at least one biocompostable resin, one or more fillers, a compatibilizer, a dispersant and a polyester plasticizer. A molded product, according to the present invention, it is a product molded with the above mentioned biocompostable compound.

Description

DESCRIPTION

"BIOCOMPOSTABLE POLYMER BLENDS"

Field of invention

The present invention refers to the formulated blends and corresponding molded products. Specifically, the invention refers to a biocompostable composition and its molded product which comprises one or more biocompostable polymers . State of the art

Following increasing environmental concerns, biocompostable polymers and resins which are degradable by the action of microorganisms have been object of much research and development. Specific examples of the above mentioned biocompostable resins include moldable polyesters, like polyhydroxybutyrate , polycaprolactone, polylactic acid and polybutylene succinate, as well as their copolymers.

However, these polyesters, as well as the resins produced by microorganisms (e.g. : polyhydroxybutirate) , imply extremely high production costs and the use of synthetic biocompostable resins (e.g.-. polycaprolactone, polylactic acid, polybuthylene succinate, etc.), which are 2 to 4 times more expensive than widely used conventional polymers. It is the high cost of these polymers that rends unfeasible a broader use of biocompostable resins.

More recently, in order to deal with the high cost of biocompostable resins, studies were made with a focus on formulations of biocompostable materials with organic or inorganic fillers with the aim of reducing the cost of intermediate and final products. The use of starches may contribute to increase the rate of biodegradation .

However, in the above mentioned formulations of biocompostable materials with organic or inorganic fillers it is necessary to use an agent or process of promoting their compatibility (e.g. by treating the surface of the filler or by increasing chain length) , because in cases of limited compatibility between the biocompostable resin and the filler, the mechanical resistance of the blend will be limited, rending it difficult to use in some applications ,- and due to possible early degradation of the resin when submitted to some mixing processes. In order to overcome the previously mentioned problems, several processes have been patented:

1 - Patent 09631561 proposes a process in two steps, comprising the synthesis of thermoplastic starch from starch, sorbitol and glycerol, followed by its blending with a biocompostable resin. However, this process faces some limitations regarding the mixture of the ionic compound containing sorbitol and glycerol with a polyester based biocompostable resin, as the higher the temperatures used, the more significant will be the decrease on the performance and mechanical properties of the resin. Besides this, this process is incapable of rending a good compatibility between the thermoplastic starch and the biocompostable resin.

2 - Patent EP0542155 proposes a process in which one of the steps is a mixture of starch with a cellulose ester. However, this process yields a material with limited tensile strength, (less than 200 %) .

3 - Patent JP10211959 proposes a process in which the acetylene glycol grafted with ethylene oxide is used in a mixture of cornstarch and a biodegradable resin. However, this process has the problem that the mixture of components that have some acidity (for example the compound acetylene glycol) with a biodegradable resin, with a polyester structure, results in the deterioration at high temperatures by acid hydrolysis. Moreover, this process is insufficient to make compatible the biodegradable resin and the corn starch.

4 - Patent US6515054 proposes a process comprising the step of mixing a starch polymer, a biodegradable resin and an ionic surfactant. This process is insufficient to make compatible the biodegradable polymer resin and starch, especially if it is a resin of high molecular weight.

5 - Patent JP7330954 considers the process of polyethylene glycol introduction as one diol component in a aliphatic polyester with intention to form a hydrophilic aliphatic polyester and mixing it with starch. However, it is difficult to say that the introduction of the component diol in the formation of the aliphatic polyester, only introduced with the intention to increase the compatibility with the starch, is an easy process. Moreover, this process disturbs crystalline structure, therefore, it decelerates the speed of crystallization in the stage of molding. 6 - Patent JP10152602 considers the process where it is used polyethylene glycol in one mixture of starch and biodegradable resin. However, this process uses a high hydrophilic material as polyethylene glycol, and the resultant mixture could be sticky, due to the absorption/adsorption of moister; the biodegradable resin can lose mechanical properties with the passing of time due to water absorption by the polyethylene glycol, or even polyethylene glycol to be so hydrophilic that the compatibility with the biodegradable resin becomes very low.

7 - Patents JP10158485 and JP6313063 consider a process in which an aliphatic polyester of low molecular weight is added to a mixture of an aliphatic polyester of a high molecular weight and starch. However, there is not any evidence that the synthesis of two types of aliphatic polyesters of high and low molecular weight with the intention to increase compatibility with the starch is an easy process. Moreover, this process alone is applicable to determined aliphatic polyesters, therefore is very conditioned in its use.

8 - Patents JP5331315 and JP8188671 consider a process that comprises the stage of a mixture of a aliphatic polyester with a wet starch that is prepared by addition of water to a starch. However, this process can induce the hydrolysis of the biodegradable resin by the water, weakening it. Moreover, this process is, in general, insufficient to make compatible the biodegradable resin and the starch.

9 - Patent JP6271694 proposes the process of mixing a starch polymer, a poly (alcohol vinyl) , and a nonionic surfactant in which the polymer starch has a water content of 5-30% wt . However, this process may induce the hydrolysis of the biodegradable resin. Furthermore it appears experimentally that this process is insufficient to make compatible the biodegradable resin and starch.

SUMMARY OF THE INVENTION

A. Object of invention

In order to solve the problems described above, the objective of the present invention is to provide biocompostable resin compositions and its processed product, where the biocompostable resin composition exhibits excellent biodegradability and excellent mechanical strength and is economically affordable, easy to process, and usable in a wide range of purposes.

B . Disclosure of invention

Considering these situations, the inventors studied diligently the aforementioned problems in order to solve them. As a result, they found that inj ectability and processability of the biocompostable compound improved considerably, and the compatibility and dispersibility between the discontinuous and continuous phase were excellent due to mixtures of polyester and native starch being strengthened by the addition of a compatibilizer agent, a dispersant and a plasticizer of the polyester. Thus, a biocompostable mixture, according to the present invention comprises at least one linear biocompostable resin produced from two monomers, one or more fillers, a compatibilizer agent, a dispersant and a plasticizer of the polyester. A molded product according to the present invention is a molded product made from the biocompostable mixture above. These and other objectives and advantages of this invention will have a detailed definition in section

"Detailed description of the invention" DETAILED DESCRIPTION OF THE INVENTION

There is no special limitation on the biocompostable resin to use in this invention as long as it is a thermoplastic resin with biodegradability . Specific examples of biocompostable resins include : polyesters of medium/high molecular weight and biocompostable polymers containing aromatic dicarboxylic acids as essential structural units.

The average molecular weight of a high molecular weight polyester in the present invention is not particularly limited, but should be around, for example, from 10,000 to 300,000, preferably in the range from 25,000 to 300,000, mostly in the range from 40,000 to 300,000. In the case of the average molecular weight of a high molecular weight aliphatic polyester being smaller than the range described above, the resin will show low values of mechanical strength not allowing disabling its use in applications such as molded product, which requires physical strength.

The polyester of high molecular weight can be obtained, for example, through: a) a process comprising a polycondensation step of a polycarboxylic acid (or ester thereof) with a glycol, b) a process comprising the step of polycondensation of hydroxycarboxylic acid (Or an ester thereof) , c) a process comprising the polymerization step of opening a ring of a cyclic anhydride with a cyclic ether, or d) a process comprising the polymerization step of a opening a ring of a cyclic ester.

Examples of polycarboxylic acids used in above process a) include succinic acid, adipic acid, suberis acid, sebacic acid, azelaic acid, decanedicarboxylic acid, octadecanedicarboxylic acid, dimeric acids, and related esters. Examples of glycols used in the process: ethylene glycol, propylene glycol, 1 , 3 -propanediol , 1 , -butanediol , neopentyl glycol, 1 , 5 -pentanediol , 1 , 6 -hexanediol and decamethylene glycol as well as diols and triols derived from sugars. In addition, polyoxyalkylenes , like polyoxyethylene glycol, polyoxypropylene glycol, polyoxytetramethylene glycol, and their copolymers are also available as a part of the glycol components. Preferably a combination of succinic acid with ethylene glycol and/or a combination of succinic acid with 1, 4-butanediol having in consideration the melting point, and the biodegradability as the economic advantage of the resulting polyester.

Examples of the hydroxycarboxylic acid used in the process b) include glycolic acid, lactic acid, 3- hydroxypropionic acid, 3-hydroxy-2 , 2-dimethylpropionic acid, 3-hydroxy-3-methylbutyric acid, 4-hydroxybutyric acid, 5-hydroxyvaleric acid, 3 -hydroxybutyric acid, 3- hydroxyvaleric acid, 4-hydroxyvaleric acid, 6- hydroxycaproic acid, citric acid, malic acid and their esters .

Examples of cyclic anhydrides used in the process c) include succinic anhydride, maleic anhydride, itaconic anhydride, glutaric anhydride, adipic anhydride and citraconic anhydride. Examples of cyclic ether include ethylene oxide, propylene oxide, cyclohexene oxide, styrene oxide, epichlorohydrin, alyll glicidyl ether, phenyl glicidyl ether, tetrahydrofuran and 1 , 3-dioxolane . Preferably among this is the combination of succinic anhydride with ethylene oxide, taking into account the point of fusion, biodegradability and the economic advantage of the resulting polyester. The ring-opening polymerization can be accomplished by methods such as polymerization in inert solvents (e.g. toluene and xylene, hexane, n-hexane, dioxane, chloroform, dichloroethane) or bulk polymerization, where the method involves the use of a conventional ring opening polymerization catalysts, such as metal oxides compounds (for example, compounds of zirconium octanoate, tetraalkoxyzirconium, trialkoxyaluminum.

Examples of the cyclic ester used in the process) include [beta] -propiolactone, [beta] -methyl- [beta] - propiolactone, [delta] -valerolactone, [epsilon] - caprolactone, glycolic acid and lactic acid. The ring- opening polymerization can be made, like the process iii) by the method of polymerization in inert solvents or by bulk polymerization method involving the use of conventional catalysts in the ring-opening polymerization.

In process c) , it is preferable the inclusion of a ring-opening polymerization step of an anhydride cyclic with a cyclic ether, because it is a process that allows producing a polyester with high molecular weight and a good manufacturing efficiency within a relatively short space of time compared to other production processes of aliphatic polyesters of high molecular weight .

In the event that the average molecular weight of a polyester obtained by the processes a) , b) , c) or d) is smaller than 10,000, it can be converted into a high molecular weight polyester by a transesterification reaction or a chain reaction with various chain extenders. Examples of chain-extending agents include isocyanate compounds, epoxy compounds, aziridine compounds, oxazoline compounds polyvalent metal compounds, polyfunctional acid hydrides, phosphoric acid esters and phosphorous acid esters. These can be used alone or in combination, with each other. There are several methods for the reaction between the polyester and the chain extending agent but examples thereof include: a method comprising the steps of dissolution of the polyester in a suitable solvent and then make the polyester chain react with the chain extender or a method comprising the steps of melting the polyester, and then making it react with the chain extender.

In the present invention, the biocompostable polymers containing dicarboxylic acids, and essential chain extenders as structural units, are not limited with respect to molecular weight, but will be desirable to have an average molecular weight of 5,000 to 300,000, preferably 10,000 to 300,000, mainly 20,000 to 300,000, and the melting point from 60 to 200 °C, preferably in the range of 80-160 °C, and concrete examples of this situation include polyesters, polyester ethers, polyester amides and polyether ester amides, and polyester urethanes.

The biocompostable polyesters containing aromatic dicarboxylic acids as essential structural units are, for example, obtainable by conventional processes involving the main use of either or both of terephthalic acid (or its ester) and adipic acid (or its ester) with the following compounds: glycols having at least two carbon atoms, compounds having at least three groups that may form esters, sulfonate compounds, hydroxycarboxylic acid; diisocyanates ,- bisoxazoline, or divinyl ether.

Moreover, it is also possible to prepare the biocompostable resin by synthesizing a copolymer and a biocompostable polyester separately and mix them with melt- kneading, carrying out a conventional transesterificatio . Examples of saturated polyesters, with wide use, include polyethylene terephthalate, polybutylene terephthalate, poly (ethylene 1 , 4 -cyclo-hexanedimethylene) , poly (1,4- ethylene terephthalate-cycle hexanedimethylene) , poly (1,4- cyclo-isophthalate hexanedimethylene ethylene) and poly (ethylene naftalenedicarboxylate) and its copolymers. Examples of biocompostable polyester are: polyethylene succinate, polybutylene succinate, polybutylene succinate adipate, poly-hexamethylene succinate, polyethylene adipate, poly-hexamethylene adipate, polybutylene adipate, polyethylene oxalate, polybutylene oxalate, polyneopentyl oxalate, polyethylene sebacate, polybutylene sebacate, poly-hexamethylene sebacate, poly (Glycolic acid) and poly (lactic acid) or their copolymers, poly ( [omega] - hydroxyalkanoates) such as poly ( [epsilon] -caprolactone) and poly ( [beta] -propiolactone) poly ( [beta] - hydroxyalkanoates) such as poly (3 -hydroxybutyrate) , poly (3 -hydroxyvalerate) , poly (3 -hydroxycaproate) , poly (3- hydroxy-heptanoate) and poly (3 -hydroxyoctanoate) and poly (4 -hydroxybutyrate) . Moreover, the average molecular weight of the biocompostable polyester is normally in the range of

5,000 to 300,000, preferably in the range of 10,000 to 300,000, especially in the range of 30,000 to 300,000, mainly from 50,000 to 300,000.

The proportion of biocompostable resin above in the biocompostable mixture is not particularly limited, but rather walk in the range of 10 to 95% by weight, especially 30 to 90% by weight, more especially 40 to 85% by weight of the biocompostable mixture. If the relationship biocompostable resin/biocompostable compound is less than the range above, the mechanical strength of the compound will be compromised.

The filler in the present invention is not especially limited, but organic fillers which have biodegradability are preferable. Specific examples include starches (e.g. starch polymers, natural starch extracted from plants) , poly (vinyl alcohol) poly (ethylene oxide) , cellulose derivatives, cellulose and natural rubber. These can be used alone or in combination with each other. In the present invention, particularly preferable among the above-exemplified fillers are the starches (e.g. polymers of starch, starch extracted from natural plants) which include native starch (starch grains as corn starch, potato starch, sweet potato starch, wheat starch, tapioca starch, corn starch, rice starch, bean starch, arrowroot starch, potato starch and lotus starch) , physically modified starches (for example, [alpha] starch, fractionated amylose, moistly and thermally treated starch) , enzymatically modified starches (for example, hydrolyzed dextrin, enzymolyzed dextrin, amylase) starches modified by chemical decomposition (for example, acid- treated starch, oxidized starch by hypochlorous acid, dialdehyde starch) , chemically modified starch-derivatives (e.g. esterified starch, starch etherified, cationized starch, crosslinked starch) and their mixtures. Examples of the esterified starch among the chemically modified starch derivatives include: acetate-esterified starch, succinate- esterified starch, nitrate-esterified starch, phosphate- esterified starch, urea phosphate-esterified starch, xanthate-esterified starch and acetoacetate-esterified starch. Examples of etherified starch include allyl- etherified starch, methyl -etherified starch, carboxymethyl - etherified starch, hydroxyethyl -etherified starch, and hydroxypropyl-etherified starch. Examples of cationic starch include: a product from a reaction between starch and 2 -diethylaminoethyl chloride; a product from a reaction between starch and 2 , 3 -epoxypropyltrimethylammonium chloride; high amylopectin starch; high araylose starch, ethoxylated starch and crosslinked starch.

The preference regarding the fillers in this invention, among the starches exemplified above is corn starch, potato starch, sweet potato starch and wheat starch. The use of starch as filler keeps the biodegradability and moldability without reducing the mechanical strength.

In addition, the starches exemplified above can be converted into thermoplastic starch by the addition of water , or alcoholic compounds, or by devising treatment methods such as heating treatment. These thermoplastics starches are particularly preferred for molded end products .

In the case of using this type of fillers, their proportion should be preferably not more than 80% of weight, especially not more than 60% of weight, especially not exceeding 50% by weight of the composition of the biocompostable resin.

If the amount of the filler above mentioned, will be higher than 50% of the weight of the composition of the biocompostable resin, the dispersibility could be affected, causing physical properties deteoration such as mechanical strength reduction. In the present invention, the biodegradable organic fillers mentioned above, are preferable as fillers, but inorganic and/or not biodegradable organics fillers may be used as filler for the application of the composition of the biocompostable resin in various methods of molding. If the filler is not biodegradable, its proportion should preferably be no more than 49% by weight, still more preferably not exceeding 40% by weight, especially not exceeding 35% by weight of the composition of the biocompostable resin. In the case where the proportion of inorganic or organic substances, used as fillers and not biodegradables , is higher than the range above, the biodegradability of the compound may be impaired and will be difficult to fulfill the definition of biocompostability by the European regulation EN 13432. The dispersion in the biocompostable resin will also be more difficult, causing deterioration of the physical properties, such as a decreasing in mechanical strength. Examples of inorganic compounds used as fillers are: calcium carbonate, clay, talc, aluminum hydroxide and magnesium hydroxide.

There is no special limitation on the use of a compatibilizer agent in the present invention if, for example, it has a structure containing polar groups, preferably hydroxyl and carboxyl groups, such as ethyl vinyl acetate, hydrolyzed ethyl vinyl acetate, ethyl glicidyl acrylate, ethyl methyl methacrylate, ethylene anhydride maleic and ethylene-acrylic acid, and mixtures thereof . The above mentioned addition of a compatibilizing agent is not particularly limited, but should be in the range of 0.1 to 85% by weight, preferably in the range 0.1 to 50% by weight, especially in the range of 0.1-20% by weight, more especially in the range of 0.5 to 10% by weight of the biocompostable mixture. If the proportion of the compatibilizer agent is less than 0.5% by weight of the biocompostable mixture, it may not be sufficiently grafted and the desired effect not be achieved or fully achieved thereby diminishing the physical characteristics of the end product. Moreover, in cases where the proportion of the compatibilizer agent is greater than 10% of the biocompostable mixture weight, the quantity can be too high causing a decrease in the mechanical resistance making the material inapplicable for certain purposes.

There is no special limitation on the use of the dispersant in the present invention if it has, for example, a structure containing a hydrophobic group and a hydrophilic group in its molecule where the hydrophilic group can be converted into an anion in the form of metal salts of carboxylic or sulphonic acids in water. Containing a dispersant in the blend, the compatibilisation between the biocompostable resin and fillers is much easier.

Examples of possible dispersants include: aliphatic carboxylic acids such as lauric acid, myristic acid, palmitic acid, stearic acid and oleic acid, fatty acid soaps such as sodium or potassium salts of the above aliphatic carboxylic acids and salts of N-acyl-N- methylglycine , salts of N-acyl-N-methyl- [beta] -alanine, salts of the acid N-acylglutamic , salts of polyoxyethylene alkyl ether carboxylicacylated peptides, salts of the acidalkylbenzenesulfonic , alkylnaphtalenesulfonic acid salts, dialkylsulfosuccinic acid ester salts, alkyl sulfosuccinate disalts, polyoxyethylene alkylsulfosuccinic acid disalts, alkylsulfoacetic acid salts, [alpha] - olefinsulfonic acid salts, N-acylmethyltaurine salts, sodium dimethyl 5-sulfoisophthalate, sulfated oil, monoglysulfate , sulphuric acid ester salts of fatty acid alkylolamides, alkylphosphoric acid salts, sodium dioctylsulphosuccinate , sodium dihexylsulphosuccinate , sodium dicyclo-hexylsulphosuccinate, sodium diamylsulfosuccinate, sodium diisobutylsulfosuccinate , disodium isodecylsulfosuccinate, disodium N- octadecylsulfosuccinamide, tetrasodium N-(l,2- dicarboxyethyl) -N-octadecylsulfosuccinamide , sodium diisopropylnaphthalenesulfonate and neutralized condensed products from sodium naphthalenesulfonate . These dispersants may be used alone or in combinations between them.

In the present invention, the preferred dispersants on the above list are: lauric acid myristic acid, palmitic acid, stearic acid and oleic acid; soaps of fatty acids such as sodium or potassium salts of the above aliphatic carboxylic acids, as these can have more efficiency in dispersing the fillers in the biocompostable resin . The addition of the dispersant above is not especially limited, but should be in the range of 0.001 to 100% by weight, preferably in the range from 0.01 to 50% by weight especially in the range of 0.1-20% by weight, more especially in range 0.1 to 10% by weight of biocompostable resin. If the proportion of dispersant is less than 0.001% by weight of biocompostable resin, this may not be completely covered and the desired effect is not achieved or fully achieved thereby decreasing the physical characteristics of the final product. Moreover, in the case that the proportion of dispersant is over 100% by weight of biocompostable resin, the amount can be too high to a biocompostable mixture with sufficient mechanical resistance .

On the other hand, the proportion of dispersant mentioned above can be used in the range of 0.1 to 100% of the filler weight, preferably in the range of 0.2 to 50% by weight, especially in the range of 0.3 to 30% by weight, more especially in the range 0.3 to 20% by weight, of the filler. In the case where the proportion of dispersant is less than 0.1% by weight of the load, the surface of the filler probably will not be adequately treated and the desired effect will not be achieved or fully achieved thereby decreasing the physical characteristics of the final product. Moreover, in the case that the proportion of dispersant is over 100% of the weight of the filler, this amount may be too high for a biocompostable resin composition with sufficient mechanical strength.

The relationship between the above-mentioned dispersant, to satisfy both the proportions above regarding the biodegradable resin and the filler is preferably within the range of 0.05 to 20% by weight of the biocompostable resin composition.

The biocompostable resin composition according to the present invention preferably includes a plasticizer. The plasticizer will work like a viscosity reducer of the biodegradable resin facilitating the dispersion of the fillers in the matrix. Examples of plasticizers include phthalates, phosphoric compounds, adipic acid compounds, sebacic compounds, azelaic compounds, citric acid compounds glycolic acid compounds, trimellitic compounds, phthalic isomer compounds, ricinoleic compounds, polyester compounds, epoxidized soybean oil, epoxy butyl stearate, epoxidized octyl stearate, chlorinated paraffins, chlorinated fatty acids esters, fatty acid compounds, vegetable oils, pigments and acrylic compounds. These plasticizers can be used alone or in combination.

Specific examples of the above phthalates include dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dihexyl phthalate, di-n-octyl phthalate, di-2 -ethylhexyl phthalate, diisooctyl phthalate, dicapryl phthalate, dinonyl phthalate, diisononyl phthalate, didecyl phthalate, diundecyl phthalate, dilauryl phthalate, ditridecyl phthalate, dibenzyl phthalate, dicyclohexyl phthalate, butyl benzyl phthalate, octyl decyl phthalate, butyl octyl phthalate, octyl benzyl phthalate, n-hexyl n-decyl phthalate, n-octyl phthalate, and n-decyl phthalate.

Specific examples of the above phosphoric compounds include: tricresyl phosphate, trioctyl phosphate, triphenyl phosphate, octyl diphenyl phosphate, cresyl diphenyl phosphate, and trichloroethyl phosphate.

Specific examples of the above adipic compounds include: dioctyl adipate, diisooctyl adipate, di-n-octyl adipate, didecyl adipate, diisodecyl adipate, n-octyl n- decyl adipate, n-heptyl adipate, and n-nonyl adipate.

Specific examples of the above sebacic compounds include, dibutyl sebacate, dioctyl sebacate, diisooctyl sebacate, and butyl benzyl sebacate.

Specific examples of the above azelaic compounds include: dioctyl azelate, dihexyl azelate, and diisooctyl azelate .

Specific examples of the above citrate compounds include: triethyl citrate, acetyl triethyl citrate, tributyl citrate, acetyl tributyl citrate, and acetyl trioctyl citrate. Specific examples of the above glycolic compounds include: methyl phthalyl ethyl glycolate, ethyl phthalyl ethyl glycolate, and butyl phthalyl ethyl glycolate.

Specific examples of the above trimellitic compounds include: trioctyl trimellitate and tri-n-octyl n- decyl trimellitate.

Specific examples of the above phthalic isomer compounds include: dioctyl isophthalate and dioctyl terephthalate .

Specific examples of the above ricinoleic compounds include methyl acetyl ricinoleate and butyl acetyl ricinoleate.

Specific examples of the above polyester compounds include polypropylene adipate and polypropylene sebacate .

Among the plastic!zers above, the most suitable are composed of adipic acid.

There is no specific limitation regarding the quantity of plasticizer that can be used as long as it is in the range of 0.001 to 90% of the total weight of the biocompostable blend, however this quantity should be preferably in the range of 0.01 to 70% of the total weight of the biocompostable blend, especially within 0.1 to 60% of the total weight of the biocompostable blend, more specifically between 0.5 and 30% of the total weight of the biocompostable blend. In case the percentage of plasticizer in the blend is inferior to the lower limit of the above mentioned interval, its purpose in the formulation can be considered irrelevant, therefore not having the necessary effect which should be expected, which is to allow a better dispersion of the filler in the biodegradable resin. On the other hand, in case the percentage of plasticizer exceeds the upper limit of the same interval, the resultant compound may have a very low viscosity and fail to have the necessary mechanical properties to the final molded product or exudation of the plasticizer can occur due to saturation .

If necessary, the composition of the biodegradable resin can include other components that do not put at risk the purpose of the invention. Examples of these components can be pigments, colorants, heat resistance agents, ultraviolet stabilizers, lubricants, anti-static agents, low vapor tension solvents, reinforcing agents, flame retardants and other polymers.

The content in water of each one of the main components of the biocompostable blend according to the present invention (biocompostable resin, filler, dispersant and plasticizer) is not specially limited, although the lesser moisture in the blend, the better will be the physical behavior of the molded product. Specifically, the content in water in each of the components should not be more than 10% in weight, preferably not more than 1% in weight, specially not more than 0.1% in weight, more specifically not more than 0,01% in weight. In case the content in water of each component is superior to 10% the hydrolysis of the biocompostable resin may be accelerated causing a reduction of the molecular weight of the resin, which may result in a decrease of the mechanical properties of the biocompostable blend.

The blending and processing method of the components of the biocompostable resin, according to the present invention, includes a twin screw extruder that can have a cone-shaped or parallel configuration with high compression rate and vertical-gravimetric feeders for solids and liquids.

The feeding of the raw materials in the composition of the biocompostable resin can be made in different zones of the extruder depending on the type of components used.

The screws can be composed by kneading zones, transport zones and mixing zones .

The extruder should have, depending on the L/D ratio, at least two degassing zones, one operating through a vacuum system and another through free exhaust in a way to ensure that the compound has the lowest possible water content, which should be under 5%, preferably under 1%, specially under 0.5%, particularly under 0.1%.

The necessary temperature to the mixing, fusing and transforming of this biocompostable blend, which contains biocompostable resin, filler, dispersant and plasticizer is not specifically limited, but should be in the range of 50 to 250°C, preferably between 60 and 230°C, more conveniently between 80 and 200°C, particularly between 90 and 180 °C. In case the temperature of the mixing is lower than 50 °C, the melting point of the biocompostable resin may not be reached, and therefore gelification does not occur, which results simply in a mixture of components which are not fused together, and the fusing is absolutely necessary to a biocompostable blend with high mechanical resistance. On the other hand, if the temperature exceeds 250 °C the biocompostable resin may suffer degradation from the heat, which may result in a reduction of its molecular weight in a way that a biocompostable blend with high mechanical resistance cannot be achieved.

According to the present invention, the molded product results from the above mentioned biocompostable compound and can be used for various ends: recipients, tools, film, foils, fibers, foams, laminates, fabrics and non-fabrics. The molded product, according to the present invention, is characterized for being biocompostable, having excellent molding ability and mechanical resistance, and having the ability to be transformed through the conventional methods (injection molding, extrusion, blow- molding, blow-extrusion, calendaring and thermoforming) .

Effects and benefits of the Invention

According to the present invention, the biocompostable blend is biocompostable by definition of the EN 13432 standard and easily processable in the molding of the final product. Furthermore, and according to the present invention, it is a moderate cost material.

The composition of the biocompostable resin, according to the present invention, can be used in materials to produce: disposable packages, first-need products, daily usage products among many other possibilities .

According to the present invention, the molded product is biocompostable, has excellent molding ability and mechanical resistance, and can be easily processed through conventional methods, such as injection molding, extrusion, blow-molding, blow-extrusion, calendaring and thermoforming .

Thus, the molded product, according to the present invention, is useful in many ways and usages, such as recipients, film, foils and fibers. Description of the used methods

The methods, tests and respective measured values (Al to A23) that are characteristic of this invention, in contrast with the results of other operating methods of the patents presented in the "state of the art" section are presented as follows:

Biocompostability Test

The production of film samples from every one of the above mentioned biocompostable compounds (Al to A23) was made by the blow-extrusion method, in a 25 x 25

Periplast brand conventional extruder, with a thickness of 30 to 50 microns and 120 to 130°C processing temperatures.

Each one of the films produced was placed in a small scale composting station, with controlled environment, with 65% relative humidity and 60 °C temperature .

After 120 days, every one of the film samples had virtually disappeared and the products resulting from its digestion were integrated in the surrounding biomass.

Tensile strength and elongation at break tests

The biocompostable compounds referred in tables 1, 2 and 3 were produced (Al to A15) recurring to a Brabender PL2200 Plasti-Corder at 130°C and 30 rpm during 5 minutes. The resulting mass was then pressed during 10 minutes in a hot-plate hydraulic press at 130 °C. Tensile strength and elongation at break, tests were made to each one of them according to the ISO 527 standard.

Table 1

Table 2

A9 A10 All A12 A13 A14 A15

Polyester (g) 50 50 50 50 50 50 50

Organic filler (g) 15 15 15 15 15 15 15

Low vapour pressure solvent (g) 5 5 5 5 5 5 5

Plasticizer (g) 2 2 2 2

Dispersant (g) 2 2 2 2

Compatibility agent (g) 2 2 2 2

Tensile strength MPa 17.40 17.48 17.51 17.55 17.78 17.67 17.71

Elongation % 89 236 302 171 249 201 180 According to the results in tables 1 and 2 (Al to A15) a very significant variation in the elasticity of the material can be noticed with the increase of the content in weight (2x) in the formulation of a plasticizer, a dispersant and a compatibilizer . Given that the variation of the tensile strength is not relevant, it can be concluded that there is an exceptional improvement in the bonding between the continuous and non-continuous phases with the combined addition of these components.

In tables 3 and 4 we can verify the optimization of the quantities of each one of these additives in this type of formulations (A16 to A23) :

Table 3

* Sticky to the touch Table 3 (continued)

The polyester used, has an average molecular weight of more than 100,000.

Claims

- 30 - CLAIMS

1. A biocompostable polymeric blend, that is transformable in a finished product that have the biocompostability characteristic, that is characterized by comprising at least one biocompostable resin, one or more fillers, a compatibilizer agent, a dispersant and a polyester plasticizer.

2. A blend according to claim 1, characterized by including a biocompostable resin selected from polyesters with an average molecular weight from 5000 to 300 000 and biocompostable polymers that contain essential aromatic dicarboxylic acids as structural units.

3. A blend according to claim 2, characterized by the said polyesters having an average molecular weight of 50, 000 to 300, 000.

4. A blend according to any one of claims 1 to 3, characterized by including one biocompostable resin selected from the group consisting of: polyethylene succinate, polybutylene succinate, polybutylene succinate adipate, poly-hexamethylene succinate, polyethylene adipate, poly-hexamethylene adipate, polybutylene adipate, polyethylene oxalate, polyneopentyl oxalate, polyethylene sebacate, polybuthylene sebacate and poly-hexamethylene sebacate . O 2011/065855

- 31 -

5. A blend according to any one of claims 1 to 4, characterized by comprising 10 to 95% of biocompostable resin relative to the weight of the biocompostable mixture.

6. A blend according to claim 5, characterized by comprising a portion of 40 to 85% of biocompostable resin relative to the weight of the biocompostable blend.

7. A blend according any one of claims 1 to 6, characterized by including an organic or mineral filler.

8. A blend according any one of claims 1 to 7, characterized by including a compatibility agent with a structure that contains polar groups selected from the group consisting of: ethylene vinyl acetate, hydrolyzed ethylene vinyl acetate, ethylglycidyl acrylate, ethyl methyl methacrylate , ethylene-maleic anhydride and ethylene acrylic acid, and mixtures thereof, where the addition of the said components is in the range of 0.1 to 85% relative to the weight of the biocompostable blend.

9. A blend according to claim 8 , characterized by including a part of compatibilizer from 0.5 to 10% relative to the weight of the compostable blend.

10. A blend according to any one of claims 1 to 9, characterized by including a dispersant that contains in its structure an hydrophobic group and also an hydrophilic group selected from the group consisting of: aliphatic carboxylic acids, like the lauric acid, myristic acid, palmitic acid, stearic acid and oleic acid; fatty acid soaps, like the sodium or potassium salts of the said aliphatic carboxylic acids; salts of N-acetyl-N-methyl glycine, salts of N-acyl-N-methyl- [beta] -alanine, salts of N-acyl glutamic acid, polyoxyethylene alkyl ether carboxylic, acylated peptides, salts of alkyl benzene sulphonic acid, salts of alkyl naphthalene sulphonic acid, salts of ester of dialkylsulphosuccinic acid, di-salts of alkylsulphosuccinate, di-salts of polyoxyethylene alkylsulphosuccinic acid, salts of alkyl sulphoacetic acid, salts of acids [alfa] -olefinsulphonic , salts of N- acylmethyltaurin, 5-dimethyl sodium sulphoftalate, sulphated oils, monoglysulphate, esters of sulphuric acid, salts of fatty acid alkyl oleamides, salts of alkyl phosphoric acid, sodium dioctylsulphosuccinate, sodium dihexylsulphosuccinate, sodium dicyclo- hexylsulphosuccinate, sodium diamylsulfosuccinate, sodium diisobutylsulfosuccinate, disodium isodecylsulfosuccinate, disodium N-octadecylsulfosuccinamide , tetra-sodium N-(l,2- dicarboxyethyl) -N-Octadecyl sulfosuccinamide, sodium diisopropyl naphthalene sulfonate, and condensed and neutralized products of sodium naphathalenesulfonate or mixture thereof, this compounds are added rn the range of 0,001-100% relative to the weight of biocompostable resin.

11. A blend according to claim 10, characterized by the addition of the compounds in the range of 0.1 to 10% by weight relative to the biocompostable resin.

12. A blend according to any one of claims 1 to 11, characterized by including a polyester plasticizer selected from the group of adipic acid compounds where are included the dioctyl adipate, diiso octyl adipate, di-n- octyladipate , di-n-ethyl-hexyladipate, didecyladipate, di- isodecyladipate , N-octyl-n-decyladipate , n-heptyladipate and n-nonyladipate , the addition of the said compounds are in the range of 0.01 to 70% by weight relative to the biocompostable resin.

13. A blend according to claim 12, characterized by the addition of the plasticizer on the range of 0.5 to 30% by weight relative to the biocompostable resin.

14. A blend according to any one of claims 1 to

13, characterized by including additionally other components selected from pigments, colorants, heat resistance agents, antioxidants, ultraviolet stabilizers, lubricants, anti-static agents, low vapor tension solvents, reinforcement agents, flame retardants, and other polymers.

15. A blend according to any one of claims 1 to

14, characterized by the water content of each of the main components of the biocompostable blend not being higher than 10% by weight.

16. A blend according to claim 15, characterized by the water content of each of the main components of the biocompostable blend not being higher than 0.01% by weight. O 2011/065855

- 34 -

17. A process to get a biocompostable molded product, with excellent moldability and mechanical resistance, characterized by the blend, according to any of the claims 1 to 16, being processed in an extruder that, depending on the ratio length/diameter, has at least two degassing zones, one operating through a vacuum system and another through free exhaust in a way the water content in the polymeric biocompostable blend is lower than 5% and the necessary temperature to the mixing, melting and transforming of this polymeric biocompostable blend is within a range of 50 to 250 °C.

18. Process according to claim 17, characterized by the water content of the biocompostable polymeric blend being lower than 0.1% by weight relative to the biocompostable resin, and by the necessary temperature to the mixing, melting and transforming of this polymeric biocompostable blend being within a range of 90 to 180 °C.

19. Molded product obtained according to claim

17 or 18.