US5849374A
Expired / Lapsed
US
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Compostable multilayer structures, methods for manufacture, and articles prepared therefrom
Assignee: Cargill Inc
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Filing: 1995-09-28
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Granted: 1998-12-15
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Expires: 2015-09-28
Abstract
Abstract A compostable multilayer structure in the form of a film, sheet, laminate, and the like, which comprises a core layer having a first surface and a second surface, a first blocking reducing layer covering the first surface of the core layer, and a second blocking reducing layer covering the second surface of the core layer. The core layer contains a lactic acid residue-containing polymer and has a glass transition temperature (T g ) below about 20° C. The first and second blocking reducing layers include a polymer composition of a hydrolyzable polymer and have a T g above about 50° C. The multilayer structure can be used for preparing bags and wrappers.
Inventors
- 👤 Patrick R. Gruber
- 👤 Jeffrey John Kolstad
- 👤 James Lunt
- 👤 Christopher M. Ryan
- 👤 Ali Zakareya El-Afandi
- 👤 James Nangeroni
- 👤 Nancy Uzelac Buehler
- 👤 Mark Hartmann
- 👤 Jed Richard Randall
- 👤 Andrea Lee Brosch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 18:10
CPC Classifications
B; B32; B32B; B32B27/00; B32B27/06; B32B27/08; B32B27/18; B32B27/22; B32B27/30; B32B27/306; B32B27/32; B32B27/36; B32B2250/00; B32B2250/24; B32B2250/244; B32B2307/00; B32B2307/70; B32B2307/716; B32B2307/7163; B32B2367/00; Y; Y10; Y10T; Y10T428/00; Y10T428/13; Y10T428/1303; Y10T428/1307; Y10T428/1352; Y10T428/1379; Y10T428/1383; Y10T428/24; Y10T428/24942; Y10T428/25; Y10T428/254; Y10T428/26; Y10T428/263; Y10T428/264; Y10T428/265; Y10T428/269; Y10T428/31504; Y10T428/31786; Y10T428/3179
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
128 words
A compostable multilayer structure comprising: (a) core layer having first and second opposed surfaces, said core layer includes lactic acid residue-containing polymer containing at least about 50%, by weight, lactic acid residue units, and an effective amount of plasticizer to provide the core layer with a T g below about 20° C.; (b) first blocking reducing layer covering the first surface of said core layer, said first blocking reducing layer having a T g above about 50° C. and comprising a hydrolyzable polymer; and (c) second blocking reducing layer covering the second surface of said core layer, said second blocking reducing layer having a T g above about 50° C. and comprising a hydrolyzable polymer, wherein said blocking reduced layers provide reduced blocking compared with said core layer.
Claim 2
Dependent Claim
128 words
A compostable multilayer structure comprising: (a) core layer having first and second opposed surfaces, said core layer includes lactic acid residue-containing polymer containing at least about 50%, by weight, lactic acid residue units, and an effective amount of plasticizer to provide the core layer with a T g below about 20° C.; (b) first blocking reducing layer covering the first surface of said core layer, said first blocking reducing layer having a T g above about 50° C. and comprising a hydrolyzable polymer; and (c) second blocking reducing layer covering the second surface of said core layer, said second blocking reducing layer having a T g above about 50° C. and comprising a hydrolyzable polymer, wherein said blocking reduced layers provide reduced blocking compared with said core layer.
Claim 3
Dependent Claim
18 words
The compostable multilayer structure according to claim 1, wherein said lactic acid residue-containing polymer is a polylactide polymer.
Claim 4
Dependent Claim
26 words
The compostable multilayer structure according to claim 2, wherein the polylactide polymer is a copolymer prepared by reacting lactide monomer with non-lactide or non-lactic acid monomer.
Claim 5
Dependent Claim
16 words
The compostable multilayer structure according to claim 3, wherein the non-lactide monomer is epoxidized multifunctional oil.
Claim 6
Dependent Claim
30 words
The compostable multilayer structure according to claim 2, wherein at least one of said blocking reducing layers comprises an amorphous polylactide polymer, a semicrystalline polylactide polymer, or a mixture thereof.
Claim 7
Dependent Claim
37 words
The compostable multilayer structure according to claim 1, wherein said compostable multilayer structure has a biodegradability value of about 20 percent or higher after 40 days according to ASTM D5338-92, modified to test at about 58° C.
Claim 8
Dependent Claim
37 words
The compostable multilayer structure according to claim 1, wherein said compostable multilayer structure has a biodegradability value of about 50 percent or higher after 40 days according to ASTM D5338-92, modified to test at about 58° C.
Claim 9
Dependent Claim
18 words
The compostable multilayer structure according to claim 1 having a tear resistance greater than 25 gm f /mil.
Claim 10
Dependent Claim
21 words
The compostable multilayer structure according to claim 1, wherein said core layer has a T g less than about 5° C.
Claim 11
Dependent Claim
21 words
The compostable multilayer structure according to claim 1, wherein said core layer is compounded with a peroxyketal to reduce plasticizer migration.
Claim 12
Dependent Claim
24 words
The compostable multilayer structure according to claim 1, wherein said core layer comprises at least two sublayers, wherein each sublayer comprises a hydrolyzable polymer.
Claim 13
Dependent Claim
19 words
The compostable multilayer structure according to claim 11, wherein said sublayers have different properties of flexibility and tear resistance.
Claim 14
Dependent Claim
49 words
The compostable multilayer structure according to claim 1, wherein said core layer comprises at least two sublayers, wherein at least one sublayer has a T g below about 20° C. and a second sublayer has a water vapor transmission rate of less than about 5 g-mil/100 in 2 -day.
Claim 15
Dependent Claim
16 words
The compostable multilayer structure according to claim 1, wherein said structure is transparent to visible light.
Claim 16
Dependent Claim
26 words
The compostable multilayer structure according to claim 1, wherein said core layer comprises a hydrolyzable polymer having a number average molecular weight greater than about 80,000.
Claim 17
Dependent Claim
34 words
The compostable multilayer structure according to claim 1, wherein said first blocking reducing layer and said second blocking reducing layer comprise a hydrolyzable polymer having a number average molecular weight greater than about 50,000.
Claim 18
Dependent Claim
21 words
The compostable multilayer structure according to claim 1, wherein at least one of said blocking reducing layers comprises an anti-blocking agent.
Claim 19
Dependent Claim
38 words
The compostable multilayer structure according to claim 17, wherein the anti-blocking agent is a polymer additive having a glass transition temperature above about 50° C. or a semicrystalline polymer additive having a melting point above about 90° C.
Claim 20
Dependent Claim
35 words
The compostable multilayer structure according to claim 18, wherein the polymer additive is selected from the group consisting of cellulose acetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate, cellulose acetate butyrate, and cellulose propionate butyrate.
Claim 21
Dependent Claim
37 words
The compostable multilayer structure according to claim 18, wherein the semicrystalline polymer additive is selected from the group consisting of poly(hydroxy butyrate), poly(hydroxy butyrate -co- hydroxy valerate), poly(glycolide), poly(lactide), stereocomplex of poly(L-lactide) and poly(D-lactide), and mixtures thereon.
Claim 22
Dependent Claim
13 words
A compostable multilayer sheet comprising: a multilayer structure prepared according to claim 1.
Claim 23
Dependent Claim
24 words
The compostable multilayer structure according to claim 1, wherein said core layer is at least about 70% of the thickness of the multilayer structure.
Claim 24
Dependent Claim
25 words
The compostable multilayer structure according to claim 1, wherein the first blocking reducing layer has a thickness of between about 0.05 mil and 0.5 mil.
Claim 25
Dependent Claim
45 words
A compostable multilayer structure according to claim 1, wherein the core layer comprises a polymer blend of poly(lactide) polymer and at least one different hydrolyzable polymer selected from the group consisting of poly(glycolide), poly(hydroxybutyrate), poly(hydroxybutyrate-co-hydroxyvalerate), poly(caprolactone), poly(ethylene-oxylate), poly(1,5-dioxepan-2-one), poly(1,4-dioxepan-2-one), poly-(p-dioxanone), poly(delta-valerolactone), poly(trimethylene carbonate), and polyester.
Claim 26
Dependent Claim
29 words
A compostable multilayer structure according to claim 1, wherein the core layer comprises a polymer blend of poly(lactide) polymer and at least one different hydrolyzable polymer comprising aliphatic polyester.
Claim 27
Dependent Claim
95 words
A compostable multilayer structure comprising: (a) a compostable substrate; (b) a core layer having first and second opposed surfaces, said core layer includes lactic acid residue-containing polymer containing at least about 50%, by weight, lactic acid residue units, and an effective amount of plasticizer to provide the core layer with a T g below about 20° C.; and (c) block reducing layer covering said core layer, said blocking reducing layer having a T g above about 50° C. and comprising hydrolyzable polymer, wherein said blocking reducing layer provides reduced blocking compared with said core layer.
Claim 28
Dependent Claim
95 words
A compostable multilayer structure comprising: (a) a compostable substrate; (b) a core layer having first and second opposed surfaces, said core layer includes lactic acid residue-containing polymer containing at least about 50%, by weight, lactic acid residue units, and an effective amount of plasticizer to provide the core layer with a T g below about 20° C.; and (c) block reducing layer covering said core layer, said blocking reducing layer having a T g above about 50° C. and comprising hydrolyzable polymer, wherein said blocking reducing layer provides reduced blocking compared with said core layer.
Claim 29
Dependent Claim
16 words
The compostable multilayer structure according to claim 26, wherein said compostable substrate is a cellulose-containing substrate.
Claim 30
Dependent Claim
14 words
The compostable multilayer structure according to claim 27, wherein the cellulose-containing substrate is paper.
Claim 31
Dependent Claim
12 words
A compostable bag comprising: a multilayer structure prepared according to claim 26.
References Cited (Backward Citations)
US5216050A
Cited
US5424346A
Cited
US5444113A
Cited
WO1990001521A1
Cited
US5180765A
Cited
WO1990003156A1
Cited
US5252642A
Cited
US5108807A
Cited
US5091262A
Cited
WO1992004413A1
Cited
US5300576A
Cited
US5247059A
Cited
US5274073A
Cited
US5391423A
Cited
WO1994000293A1
Cited
EP0587069A1
Cited
EP0589437A1
Cited
WO1994006856A1
Cited
US5338822A
Cited
WO1994007941A1
Cited
WO1994008078A1
Cited
US5475080A
Cited
US5484881A
Cited
US5536807A
Cited
US5359026A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-12-14 | 2002-06-15 | 2002-12-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-12-14 | 2006-06-15 | 2006-12-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-12-14 | 2010-06-15 | 2010-12-15 | $7700.00 | Window Closed / Lapsed |