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Title:
BIODEGRADABLE PLASTIC MATERIALS
Document Type and Number:
WIPO Patent Application WO/2009/122375
Kind Code:
A2
Abstract:
A plastic material is described, obtained from monomers comprising functional groups partially replaced by proteins.

Inventors:
CATINARI MADRISANO (IT)
Application Number:
PCT/IB2009/051412
Publication Date:
October 08, 2009
Filing Date:
April 03, 2009
Export Citation:
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Assignee:
CATINARI MADRISANO (IT)
International Classes:
C08G18/64; C08G69/36; C08G69/42; C08G81/02
Domestic Patent References:
WO2004065450A22004-08-05
Foreign References:
EP0773246A11997-05-14
US4327195A1982-04-27
US3629162A1971-12-21
US20020031669A12002-03-14
JPH0457881A1992-02-25
JP2006022469A2006-01-26
Attorney, Agent or Firm:
FAGGIONI, Carlo, Maria et al. (Via S. Agnese 12, Milano, IT)
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Claims:
CLAIMS

I) Plastic material obtained from monomers comprising functional groups, characterised in that said functional groups are partially replaced by homologous functional groups of proteins. 2) Plastic material as claimed in claim 1) , characterised in that it is based on polymers included in the group containing polyurethanes, polyethylenterephtalate, polypropyleterephtalate, ethylene and vinyl acetate (EVA) copolymer, nylon, rayon, polyvinyl chloride (PVC) . 3) Plastic material as claimed in claim 2), characterised in that it is chosen among polymers based on polyurethane or ethylene and vinyl acetate copolymers .

4) Plastic material as claimed in claim 3) , characterised in that it is based on a thermoplastic polyurethane. 5) Plastic material as claimed in claim 3) , characterised in that it is based on an ethylene/vinyl acetate copolymer.

6) Plastic material as claimed in claim 5) , characterised in that vinyl acetate ranges between 5 and 80% by weight based on the finished polymer. 7) Plastic material as claimed in claim 6) , characterised in that vinyl acetate ranges between 7 and 50% by weight based on the finished polymer.

8) Plastic material as claimed in claim 7) , characterised in that vinyl acetate ranges between 10 and 40% by weight based on the finished polymer.

9) Plastic material as claimed in any one of the preceding claims, characterised in that the protein amount ranges between 0.2 and 80% by weight based on the finished product.

10) Plastic material as claimed in claim 9) , characterised in that the protein amount ranges between 1 and 70% by weight based on the finished product .

II) Plastic material as claimed in claim 10) , characterised in that the protein amount ranges between 1.5 and 60% by weight based on the finished product . 12) Plastic material as claimed in any one of the preceding claims, characterised in that said protein is chosen from the group consisting of egg white and proteins obtained by pressing

of soybeans, rapeseed, sunflower and from corn germ.

13) Plastic material as claimed in any one of the preceding claims, characterised in that said protein is partially replaced by a polysaccharide .

14) Process for the manufacture of a plastic material as claimed in any one of the preceding claims, characterised in that it provides that part of the monomer comprising functional groups is replaced with the protein.

Description:

BIODEGRADABLE PLASTIC MATERIALS

§ * § * § *

The present invention refers to new, biodegradable plastic materials, in particular to new plastic materials obtained syn- thetically.

The use of plastic materials has become more and more popular, a process which has been ongoing for many years now. As a matter of fact, plastic materials share the advantage of combining good mechanical properties and chemical stability properties with a relative thermal stability, with the inertia in reactions with the main chemicals and with low manufacturing costs . On the other hand, the above mentioned chemical inertia has as a negative consequence the fact that the plastic materials are often difficult to dispose of, thereby piling up in the environment. In order to solve this type of drawback, plastic materials capable of decomposing independently and in a reasonable time have been devised. After a few attempts, aimed at looking for a photo-degradable plastic or a hydrosoluble plastic, the danger has been understood of such a path, which would have led to ground and water pollution, due to the fact that the plastic dissolved in water could not be confined effectively.

Plastic materials capable of biodegrading have then been studied, for example the material known as Mater Bi.

Although some patent applications filed by the owner of the present application teach to make the MaterBi material more flexible, overcoming fragility drawbacks, certainly inherent in the material, such plastic materials are manufactured starting from feedstock, which are thereby no longer available for nutrition. The object of the present invention is the manufacture of synthetic biodegradable plastic materials .

The object is achieved though a plastic material obtained from- monomers comprising functional groups, characterised in that said functional groups are partly replaced by homologous functional groups of proteins .

The present invention is focused on imparting a certain degree of biodegradability to synthetic polymers, normally only

little disposable. Among these polymers, polyurethanes , poly- ethylenterephtalate, polypropyletherphtalate, ethylene and vinyl acetate (EVA) copolymer, nylon, rayon, polyvinyl chloride (PVC) can be cited in particular. Particularly preferred are polyure- thanes and ethylene copolymer and vinyl acetate. In particular, as concerns polyurethanes, thermoplastic polyurethanes are preferred. These are linear polymers with rigid segments and flexible segments. In them, the rigid segment consists of aromatic or aliphatic isocyanates, bonded to short-chain diols. The flexible segment can consist of units of polyethere or of polyester and is chosen based on the applications for which it is used.

As regards the ethylene and vinyl acetate copolymer, it preferably comprises a content of vinyl acetate ranging between 5 and 80%, preferably between 7 and 50%, most preferably between 10 and 40%. This material advantageously combines elastomeric properties with thermoplastic properties.

According to the present invention, in such polymers the functional groups are partly replaced by reaction with proteins, i.e. with biopolymeric structures which have a number of func- tional groups useful for copolymerisation with synthetic monomers. Preferably, an amount of protein is employed varying between 0.2 and 80%, more preferably between 1 and 70%. An optimal product is obtained by adding between 1.5 and 60% of protein. The percentages are by weight, based on the finished product. Any protein can be used. Particularly advantageous, for reasons of economy and availability, proved egg white and the proteins obtained by squashing soy beans, rapeseed, sunflower and corn germ.

In order to achieve the replacement, the protein is simply mixed to one of the monomers before the polymerisation reaction, so that said reaction occurs at a temperature ranging between 20° C and 250 0 C with the direct replacement of a part of the functional groups. In the case of polyurethane, the protein partially replaces the polyols used for polymerisation, while in the case of the copolymer ethylene/vinyl acetate, the protein partially replaces vinyl acetate. In fact, a monomer containing functional groups is replaced by the protein providing func-

tional groups of similar reactivity, so that, in the end polymer, part of the units carry the conventionally-known synthetic functional group, while another part carries the proteins. During the biodegradation phase of the obtained copolymer and sub- sequently, environmentally safe products will be obtained. Moreover, since proteins generally have a more branched structure than ordinary monomers, a structure with more branching than ordinary plastic is obtained, with a resulting greater elasticity. In some cases it may be advantageous to partially replace the chosen protein with one or more polysaccharides, depending on the desired properties. For example, a small addition of chi- tosan would be sufficient to impart to the plastic material according to the invention antibacterial and antifungal properties, which are highly desirable in certain applications. A full replacement of proteins with polysaccharides, per se possible, however, implies a greater difficulty for the dissolution of other agents, such as plastifiers and/or dyes.

The polymerisation reaction is carried out exactly in the same conditions in which the reaction without replacement is carried out, or in relatively similar conditions.

The use of proteins in plastic materials according to the present invention allows bacteria to attack the plastic material, without losing in physical properties, but rather imparting desirable properties, never detected before. Moreover, unlike what has been described in some previous documents which taught to make synthetic polymers biodegradable by adding amino- acids, the addition of proteins according to the presents invention allows to do without further agents to facilitate the interaction with functional groups, saving raw materials and with an environmental advantage. As a matter of fact, the individual aminoacids do not have homologous polifunctionality, for example they cannot be used as replacements of polyols because they do not have at least two hydroxylic groups. In order to allow the use of aminoacids, they are reacted with agents which introduce that otherwise missing polifunctionality.

Such agents increase environmental costs and problems.




 
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