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US 5,076,983 AGranted
Polyhydroxy acid films
AssigneeE. I. Du Pont de Nemours and Company
InventorsGary L. Loomis, George J. Ostapchenko
Life of this patent
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Abstract
The present invention relates to a process for producing degradable, shrinkable films of polyhydroxy acid and plasticizers including melt processing the materials to obtain uniform composition, forming the composition into a film, and biaxially orienting the film. Also, non-shrinkable films are produced by heat-setting the biaxially oriented films at temperature above the composition glass transition temperature and below its melt temperature while maintaining the film under restraint. Films thus produced are useful for disposable, environmentally benign packaging and other conventional film uses.
Claims42
A process for making a self-supporting polymer film comprising:
- (a) melt processing a polymeric composition comprising:
- (I) from about 92 to about 99.9 wt % of a polyhydroxy acid polymer comprising at least one hydroxy acid unit selected from the group consisting of:
- (i) (OCR'R"COOCR'R"CO)q;
- (ii) [O(CR'R")nCO]p;
- (iii) (OCR'R"CR'R"OCR'R"CO)r;
- (iv) (OCR'R"CR'R"OCR'R"CR'R"CO)s;
- and
- (v) copolymers of (i)-(iv) with non-hydroxy acid comonomers
- wherein n is 2, 4 or 5;
- p, q, r and s are integers, the total of which ranges from about 350 to about 5,000;
- and R'and R" comprise at least one material selected from the group consisting of hydrogen, a hydrocarbyl containing 1 to 12 carbon atoms, and substituted hydrocarbyl containing 1 to 12 carbon atoms, and
- (II) from about 0.10 to about 9 wt % plasticizers comprising at least one plasticizer selected from the group consisting of monomeric hydroxy acids, cyclic dimers of monomeric hydroxy acids, non-cyclic dimers of monomeric hydroxy acids and oligomers of monomeric hydroxy acids having a molecular weight of up to about 450;
- (b) forming said composition into a film;
- and
- (c) biaxially orienting said film by stretching said film to at least two times the initial machine direction and transverse direction dimensions of said film, wherein the orienting is conducted at a temperature above the polyhydroxy acid glass transition temperature and below the melting temperature of the composition.
12 more elements
A process for making a self-supporting polymer film comprising:
- (a) melt processing a polymeric composition comprising:
- (I) from about 92 to about 99.9 wt % of a polyhydroxy acid polymer comprising at least one hydroxy acid unit selected from the group consisting of:
- (i) (OCR'R"COOCR'R"CO)q;
- (ii) [O(CR'R")nCO]p;
- (iii) (OCR'R"CR'R"OCR'R"CO)r;
- (iv) (OCR'R"CR'R"OCR'R"CR'R"CO)s;
- and
- (v) copolymers of (i)-(iv) with non-hydroxy acid comonomers
- wherein n is 2, 4 or 5;
- p, q, r and s are integers, the total of which ranges from about 350 to about 5,000;
- and R'and R" comprise at least one material selected from the group consisting of hydrogen, a hydrocarbyl containing 1 to 12 carbon atoms, and substituted hydrocarbyl containing 1 to 12 carbon atoms;
- and
- (II) from about 0.10 to about 8 wt % plasticizers comprising at least one plasticizer selected from the group consisting of monomeric hydroxy acids, cyclic dimers of monomeric hydroxy acids, non-cyclic dimers of monomeric hydroxy acids and oligomers of monomeric hydroxy acids having a molecular weight of up to about 450;
- (b) forming said composition into a film;
- and
- (c) biaxially orienting said film by stretching said film to at least two times the initial machine direction and transverse direction dimensions of said film, wherein the orienting is conducted at a temperature above the polyhydroxy acid glass transition temperature and below the melting temperature of the composition;
- and
- (d) heat-setting the biaxially oriented film by heating said film to a temperature above the polymer glass transition temperature but below the polymer melt temperature while maintaining the film under restraint.
15 more elements
A self-supporting polymer film comprised of:
- (I) from about 92 to about 99.9 wt % polyhydroxy acid polymer comprising at least one hydroxy acid unit selected form the group consisting of:
- (i) (OCR'R"COOCR'R"CO)q;
- (ii) [O(CR'R")nCO]p;
- (iii) (OCR'R"CR'R"OCR'R"CO)r;
- (iv) (OCR'R"CR'R"OCR'R"CR'R"CO)s;
- and
- (v) copolymers of (i)-(iv) with non-hydroxy acid comonomers
- wherein n is 2, 4 or 5;
- p, q, r and s are integers, the total of which may range from about 350 to 5,000;
- R' and R" comprise at least one member selected from the group consisting of hydrogen, a hydrocarbyl containing 1 to 12 carbon atoms, and a substituted hydrocarbyl containing 1 to 12 carbon atoms, and
- (II) from about 0.10 to about 8 wt % plasticizers comprising at least one plasticizer selected from the group consisting of monomeric hydroxy acids, cyclic dimers of monomeric hydroxy acids, non-cyclic dimers of monomeric hydroxy acids and oligomers of monomeric hydroxy acids up to molecular weight of about 450.
8 more elements
Dependencies are inferred from the claim text.