Special amyloses and their use for producing biodegradable plastics

A composition for producing plastics comprising from about 3% to about 40% by weight of a plasticizer and from about 60% to about 97% by weight of special amylose, said special amylose being obtainable, in one step, by chemically modifying starch comprising a mixture of amylose and amylopectine with an amylose content greater than about 65%, by treatment with a solution comprising formamide and about 2%, by weight, dichloroacetic acid and recovering special amylose;

• said special amylose being swellable, but not soluble, in liquid water at a temperature of about 20.degree. C. or below and yielding a homogenous, flowable quasi-solution without formation of gels when heated, with stirring, to a temperature of from about 80.degree. C. to about 100.degree. C., at atmospheric pressure;
• the homogenous, flowable state being maintained for at least five minutes without gel formation during cooling of said quasi-solution, from a temperature of between about 80.degree. C. and about 100.degree. C., to a temperature of about 50.degree. C.;
• and,
• said quasi-solution, at a concentration of said amylose from about 5% to about 25% by weight, being applicable to knife coating onto a planar surface with a gap width between about 100 .mu.m and about 700 .mu.m.

In a process for the thermal shaping of a molded plastic part, the improvement comprising molding a composition comprising from about 3% to about 40% by weight of a plasticizer and from about 60% to about 97% by weight of special amylose, obtainable, in one step, by chemically modifying starch comprising a mixture of amylose and amylopectine with an amylose content greater than about 65%, by treatment with a solution comprising formamide and about 2%, by weight, dichloroacetic acid and recovering special amylose;

• said special amylose being swellable, but not soluble, in liquid water at a temperature of about 20.degree. C. or below and yielding a homogenous, flowable quasi-solution without formation of gels when heated, with stirring, to a temperature of from about 80.degree. C. to about 100.degree. C., at atmospheric pressure;
• the homogenous, flowable state being maintained for at least five minutes without gel formation during cooling of said quasi-solution, from a temperature of between about 80.degree. C. and about 100.degree. C., to a temperature of about 50.degree. C.;
• and
• said quasi-solution, at a concentration of said amylose from about 5% to about 25% by weight, being applicable to knife coating onto a planar surface with a gap width between about 100 .mu.m and about 700 .mu.m.

A process for producing amylose films and sheets comprising:

• a) dissolving, in an appropriate solvent, a composition comprising from about 3% to about 40% by weight of a plasticizer and from about 60% to about 97% by weight of special amylose, obtainable, in one step, by chemically modifying starch comprising a mixture of amylose and amylopectine with an amylose content greater than about 65%, by treatment with a solution comprising formamide and about 2%, by weight, dichloroacetic acid;
• said special amylose being swellable, but not soluble, in liquid water at a temperature of about 20.degree. C. or below and yielding a homogenous, flowable quasi-solution without formation of gels when heated, with stirring, to a temperature of from about 80.degree. C. to about 100.degree. C., at atmospheric pressure;
• the homogenous, flowable state being maintained for at least five minutes without gel formation during cooling of said quasi-solution, from a temperature of between about 80.degree. C. and about 100.degree. C., to a temperature of about 50.degree. C.;
• and,
• said quasi-solution, at a concentration of said amylose from about 5% to about 25% by weight, being applicable to knife coating onto a planar surface with a gap width between about 100 .mu.m and about 700 .mu.m;
• b) filtering the resultant solution of step (a);
• c) casting the resultant solution of step (b) onto an appropriate substrate to form a cast sheet of said resultant solution;
• and
• d) drying said cast sheet by removing all but from about 5% to about 15% by weight of said appropriate solvent as compared to the weight of said composition.

A molded plastic part comprising a special amylose, obtainable, in one step, by chemically modifying starch comprising a mixture of amylose and amylopectine with an amylose content greater than about 65%, by treatment with a solution comprising formamide and about 2%, by weight, dichloroacetic acid and recovering special amylose;

• said special amylose being swellable, but not soluble, in liquid water at a temperature of about 20.degree. C. or below and yielding a homogenous, flowable quasi-solution without formation of gels when heated, with stirring, to a temperature of from about 80.degree. C. to about 100.degree. C., at atmospheric pressure;
• the homogenous, flowable state being maintained for at least five minutes without gel formation during cooling of said quasi-solution, from a temperature of between about 80.degree. C. and about 100.degree. C., to a temperature of about 50.degree. C.;
• and,
• said quasi-solution, at a concentration of said amylose from about 5% to about 25% by weight, being applicable to knife coating onto a planar surface with a gap width between about 100 .mu.m and about 700 .mu.m.

A special amylose, obtainable in one step by chemically modifying starch comprising a mixture of amylose and amylopectine with a amylose content greater than about 65%, by hydroxyalkyl derivatization of the amylose in said starch and recovering special amylose;

• said degree of hydroxyalkyl substitution in said hydroxyalkyl amylose being from about 0.05 to about 0.15;
• said special amylose being swellable, but not soluble, in liquid water at a temperature of about 20.degree. C. or below and yielding a homogenous, flowable quasi-solution without formation of gels when heated, with stirring, to a temperature of from about 80.degree. C. to about 100.degree. C., at atmospheric pressure;
• the homogenous, flowable state being maintained for at least five minutes without gel formation during cooling of said quasi-solution, from a temperature of between about 80.degree. C. and about 100.degree. C., to a temperature of about 50.degree. C., and,
• said quasi-solution, at a concentration of said amylose from about 5% to about 25% by weight, being applicable to knife coating onto a planar surface with a gap width between about 100 .mu.m and about 700 .mu.m.

A composition for producing plastics comprising from about 3% to about 40% by weight of a plasticizer and from about 60% to about 97% by weight of special amylose, said special amylose being obtainable, in one step, by chemically modifying starch comprising a mixture of amylose and amylopectine with an amylose content greater than about 65%, by hydroxyalkyl derivatization of the amylose of said starch and recovering special amylose;

• said degree of hydroxyalkyl substitution in said hydroxyalkyl amylose being from about 0.05 to about 0.15;
• said special amylose being swellable, but not soluble, in liquid water at a temperature of about 20.degree. C. or below and yielding a homogenous, flowable quasi-solution without formation of gels when heated, with stirring, to a temperature of from about 80.degree. C. to about 100.degree. C., at atmospheric pressure;
• the homogenous, flowable state being maintained for at least five minutes without gel formation during cooling of said quasi-solution, from a temperature of between about 80.degree. C. and about 100.degree. C., to a temperature of about 50.degree. C.;
• and,
• said quasi-solution, at a concentration of said amylose from about 5% to about 25% by weight, being applicable to knife coating onto a planar surface with a gap width between about 100 .mu.m and about 700 .mu.m.

In a process for the thermal shaping of a molded plastic part, the improvement comprising molding a composition comprising from about 3% to about 40% by weight of a plasticizer and from about 60% to about 97% by weight of special amylose, obtainable, in one step, by chemically modifying starch comprising a mixture of amylose and amylopectine with an amylose content greater than about 65%, by hydroxyalkyl derivatization of the amylose of said starch and recovering special amylose;

• said degree of hydroxyalkyl substitution in said hydroxyalkyl amylose being from about 0.05 to about 0.15;
• special amylose being swellable, but not soluble, in liquid water at a temperature of about 20.degree. C. or below and yielding a homogenous, flowable quasi-solution without formation of gels when heated, with stirring, to a temperature of from about 80.degree. C. to about 100.degree. C., at atmospheric pressure;
• the homogenous, flowable state being maintained for at least five minutes without gel formation during cooling of said quasi-solution, from a temperature of between about 80.degree. C. and about 100.degree. C., to a temperature of about 50.degree. C.;
• and
• said quasi-solution, at a concentration of said amylose from about 5% to about 25% by weight, being applicable to knife coating onto a planar surface with a gap width between about 100 .mu.m and about 700 .mu.m.

A process for producing amylose films and sheets comprising:

• a) dissolving, in an appropriate solvent, a composition comprising from about 3% to about 40% by weight a plasticizer and from about 60% to about 97% by weight a special amylose, obtainable, in one step, by chemically modifying starch comprising a mixture of amylose and amylopectine with an amylose content greater than about 65%, by hydroxyalkyl derivatization of the amylose of said starch;
• said degree of hydroxyalkyl substitution in said hydroxyalkyl amylose being from about 0.05 to about 0.15;
• said special amylose being swellable, but not soluble, in liquid water at a temperature of about 20.degree. C. or below and yielding a homogenous, flowable quasi-solution without formation of gels when heated, with stirring, to a temperature of from about 80.degree. C. to about 100.degree. C., at atmospheric pressure;
• the homogenous, flowable state being maintained for at least five minutes without gel formation during cooling of said quasi-solution, from a temperature of between about 80.degree. C. and about 100.degree. C., to a temperature of about 50.degree. C.;
• and,
• said quasi-solution, at a concentration of said amylose from about 5% to about 25% by weight, being applicable to knife coating onto a planar surface with a gap width between about 100 .mu.m and about 700 .mu.m;
• b) filtering the resultant solution of step (a);
• c) casting the resultant solution of step (b) onto an appropriate substrate to form a cast sheet of said resultant solution;
• and
• d) drying said cast sheet by removing all but from about 5% to about 15% by weight of said appropriate solvent as compared to the weight of said composition.

A molded plastic part comprising a special amylose, obtainable, in one step, by chemically modifying starch comprising a mixture of amylose and amylopectin with an amylose content greater than 65%, by hydroxyalkyl derivatization of the amylose of said starch, and recovering special amylose;

• said degree of hydroxyalkyl substitution in said hydroxyalkyl amylose being from about 0.05 to about 0.15;
• said special amylose being swellable, but not soluble, in liquid water at a temperature of about 20.degree. C. or below and yielding a homogenous, flowable quasi-solution without formation of gels when heated, with stirring, to a temperature of from about 80.degree. C. to about 100.degree. C., at atmospheric pressure;
• the homogenous, flowable state being maintained for at least five minutes without gel formation during cooling of said quasi-solution, from a temperature of between about 80.degree. C. and about 100.degree., to a temperature of about 50.degree. C.;
• and,
• said quasi-solution, at a concentration of said amylose from about 5% to about 25% by weight, being applicable to knife coating onto a planar surface with a gap width between about 100 .mu.m an about 700 .mu.m.