Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From carbohydrate or derivative as a reactant
Patent
1996-11-27
1998-07-14
Nutter, Nathan M.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From carbohydrate or derivative as a reactant
527305, 527315, 525 5424, C08B 3102, C08G 6308, C09J10306, D21H 1728
Patent
active
057805687
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a procedure for producing a grafted starch derivative. The invention also relates to products manufactured using this procedure and to their use.
Manufacture of a graft copolymer from corn starch and .epsilon.-caprolactone is partly known. Patent JP 04093315 describes a method for grafting native corn starch with poly-.epsilon.-caprolactone (PCL) by preconditioning the poly-.epsilon.-caprolactone with methyldicyanate and triethylamide in a toluene solution prior to the addition of native corn starch. Moreover, patent JP 05125101 describes graft copolymerization of starch with .epsilon.-caprolactone in a dimethyl acetamide solution in the presence of triethylamine and lithium chloride. Other literature relating to aliphatic polyesters deals with compounding of the above-mentioned substances. A drawback with the methods described is the use of solvents detrimental to health.
To reduce the price of aliphatic polyesters and to improve their biodegradability, they have been blended with polymers obtained from renewable natural resources, such as starch. Compounding of the polymers mentioned above can be achieved by currently known methods (described e.g. in patent PCL/EP92/00959 and in articles: Koenig, M. F. and Huang, S. J., Biodegradable Polymer/Starch Blends, Composites and Coating, Polymer. Mater. Sci. Eng., 67, 1992, pp. 290-291 and McCarthy, S. P., Tanna, S. T. and Gross, R., Biodegradation of Blends of Bacterial Polyester and Starch in a Compost Environment, Polym. Mater. Sci. Eng., 67, 1992, pp. 294-295), but the mechanical properties of polymer blends obtained by compounding deteriorate rapidly as the starch content increases. In addition to the deterioration of mechanical properties, the use of starch also increases the hydrophilicity of the product, thus reducing its water resistance. Therefore, the product is structurally unsatisfactory for many present-day applications.
In view of the circumstances described above, it is desirable to find new methods for producing hydrophobic, biodegradable products having a good water resistance and mechanical properties adequate for their applications.
With the starch derivatives grafted with an aliphatic polyester produced by the procedure of the invention, the properties described above can be achieved and the drawbacks avoided. In the procedure of the invention, starch or a starch derivative can be graft-copolymerized without a catalyst or with the aid of a suitable ring-opening catalyst with a cyclic, ring-structured ester monomer, hereinafter simply referred to as cyclic ester, which, as a result of polymerization, forms aliphatic polyester grafts in the starch or starch derivative.
In the procedure of the invention, a starch derivative grafted with aliphatic polyesters can, in optimal conditions, be manufactured without a solvent or other medium. The fact that aliphatic polyesters are grafted in starch or a starch derivative has been established by a FTIR analysis.
The procedure of the invention produces a hydrophobic product which can be used as a hot-melt adhesive component and which can partly or completely replace the commonly used non-biodegradable polymers.
The products of the invention are characterized in that they are water insoluble, hydrophobic, have a low melting point and a low water transmission.
Products manufactured by the procedure of the invention can also be used for the coating of paper or cardboard to increase the water resistance and reduce the water transmission of paper or cardboard.
The invention is described in greater detail by the aid of the following application examples. These represent typical ways of producing and using the product of the invention. The application examples are only intended to demonstrate the invention without limiting the scope of protection of the invention in any way.
The starch described in the invention may be any starch extracted from a natural raw material (true starch), e.g. barley, potato, wheat, oat, corn, tapioca, sago, rice or other tuber or grain based starch wi
REFERENCES:
patent: 5540929 (1996-07-01), Narayan et al.
Koenig et al, Polymeric Materials Sci. Engineering, vol. 67, pp. 290-291 (1992).
Tanna et al, Polymeric Materials Sci. Engineering, vol. 67, pp. 294-295 (1992).
Patent Abstracts of Japan, vol. 17, No. 492, C-1107, Abstract of JP, A, 5-125101 (1993).
Chem. Abstracts, 117(10): 91588w (1993), Abstract of JP 04093315 A2 (1992).
Peltonen Soili
Seppala Jukka
Vuorenpaa Jani
Nutter Nathan M.
Valtion teknillinen tutkimuskeskus
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