Biodegradable cellulose fiber-based substrate, its manufacturing process, and use in an adhesive tape

Abstract

A biodegradable cellulose fiber-based substrate, at least one side of which is coated with a release coating including: a) at least one water-soluble polymer (WSP) containing hydroxyl groups, and b) at least one lactone substituted with at least one linear or branched and/or cyclic C.sub.8-C.sub.30 hydrocarbon chain which may contain heteroatoms. The biodegradable substrate is certified biodegradable in accordance with EN 13432. A method of production thereof is also disclosed.

Claims

1. A biodegradable substrate comprising: (i) a cellulose fiber-based base paper, and (ii) a release coating on at least one surface of the base paper, wherein the release coating comprises, based on dry weight percentage: (a) 45-99% of at least one water-soluble polymer (WSP) containing hydroxyl groups, (b) at least one diketene compound, wherein the at least one diketene compound is substituted with at least one linear, branched and/or cyclic C8-C30 hydrocarbon chain which may contain heteroatoms, and wherein the biodegradable substrate is certified biodegradable in accordance with EN 13432.

2. The biodegradable substrate of claim 1, wherein the release coating comprises from 50-70 parts by weight of the at least one water-soluble compound to 30-50 parts by weight of the at least one diketene compound.

3. The biodegradable substrate of claim 1, wherein the at least one water soluble compound comprises polyvinyl alcohol or starch, and wherein the at least one diketene compound comprises alkyl ketene dimer.

4. The biodegradable substrate of claim 1, wherein the release coating comprises a cross-linked polymer network.

5. The biodegradable substrate of claim 1, wherein the biodegradable water soluble polymer comprises a polyvinyl alcohol, a starch, or a modified starch.

6. The biodegradable substrate of claim 1, wherein the release coating comprises, based on dry weight percentage: (a) 50-90% of the water-soluble polymer (WSP), (b) 10-40% of the at least one diketene compound.

7. The biodegradable substrate of claim 1, further comprising an adhesive layer on a surface of the base paper opposite to the release coating layer.

8. The biodegradable substrate according to claim 1, wherein the base paper comprises crepe paper.

9. The biodegradable substrate according to claim 1, wherein the water-soluble polymer (WSP) containing hydroxyl groups is selected from the group consisting of polyvinyl alcohol (PVA); starch; oxidized starch; esterified starch; etherified starch; alginate; carboxymethylcellulose (CMC); and hydrolyzed or partially hydrolyzed copolymers of vinyl acetate, ethylene-vinyl acetate copolymers, vinyl chloride-vinyl acetate copolymers, N-vinylpyrrolidone-vinyl acetate copolymers, or maleic anhydride-vinyl acetate copolymers.

10. The biodegradable substrate of claim 1, wherein the at least one diketene compound comprises a diketene molecule of the following structure: ##STR00003## wherein R1 and R2 are independent linear or branched and/or cyclic C8-C30 hydrocarbon chains which may contain heteroatoms.

11. The biodegradable substrate of claim 1, wherein (a) the at least one water-soluble polymer (WSP) is polyvinyl alcohol (PVA), (b) the at least one diketene compound is at least one alkylated diketene compound having the following structure: ##STR00004## wherein R1 is selected from the group consisting of tetradecyl (C14), hexadecyl (C16) and octadecyl (C18), and R2 is selected from the group consisting of tetradecyl (C14), hexadecyl (C16) and octadecyl (C18).

12. The biodegradable substrate of claim 1, wherein the release coating is present in the biodegradable substrate in an amount from 0.1 to 20 g/m.sup.2.

13. The biodegradable substrate according to claim 1, wherein the release coating is present in an amount from 1 to 18 g/m.sup.2.

14. The biodegradable substrate of claim 1, wherein the biodegradable substrate comprises from 0.1-40 wt % of the release coating.

15. The biodegradable substrate of claim 1, wherein the biodegradable substrate comprises an adhesive tape.

16. A process for producing a biodegradable substrate comprising: (1) forming a release coating comprising, based on dry weight percentage: (a) 45-99% of the at least one water-soluble polymer (WSP) containing hydroxyl groups, and (b) at least one diketene compound substituted with at least one linear or branched and/or cyclic C8-C30 hydrocarbon chain which may contain heteroatoms, (2) coating at least one surface of a cellulose-fiber based base paper with the release coating, and (3) drying the release coating on the at least one surface of the base paper to form the biodegradable substrate having the release coating on the least one surface of the base paper; wherein the biodegradable substrate is certified biodegradable in accordance with EN 13432.

17. The method of claim 16, further comprising applying an adhesive layer onto a second surface of the base paper opposite a first surface coated with the release coating and optionally drying the base paper with the applied adhesive.

18. The method of claim 16, wherein the biodegradable water soluble polymer comprises polyvinyl alcohol, a starch, or a modified starch.

19. The method of claim 16, wherein the release coating comprises, based on dry weight: (a) 50-90% of the water-soluble polymer (WSP), and (b) 10-40% of the at least one diketene compound.

20. An adhesive tape comprising: (i) a cellulose fiber-based paper substrate, (ii) a release coating layer on at least one surface of the paper substrate, and (iii) an adhesive layer on another surface of the paper substrate opposite to the release coating layer, wherein the release coating layer comprises, based on dry weight percentage: (a) 50-99% of at least one water-soluble polymer (WSP) containing hydroxyl groups, and (b) at least one diketene compound, wherein the at least one diketene compound is substituted with at least one linear, branched and/or cyclic C8-C30 hydrocarbon chain which may contain heteroatoms.

Description

[0151] The invention and advantages thereof will become more apparent from the following non-limiting examples given to describe the invention.

[0152] FIG. 1 illustrates a paint test to see the resistance of masking tape against paint for a 1.sup.st sample.

[0153] FIG. 2: illustrates a paint test to see the resistance of masking tape against paint for a 2.sup.d sample.

[0154] FIG. 3 illustrates a paint test to see the resistance of masking tape against paint for a 3.sup.d sample.

EMBODIMENTS OF THE INVENTION

I/1.SUP.st .Embodiment: Crepe Paper as a Substrate

1: Comparative Test

[0155] A sheet of crepe paper for masking tape (Master Tape Classic 100) with a basis weight of 39 g/m.sup.2 was treated on one side by being coated with an aqueous mixture with a dry weight of 5 g/m.sup.2 obtained according to the invention.

[0156] The composition by dry weight was composed of: [0157] 46% dry Celvol 28/99 (or 46% starch Perfectamyl A4692), [0158] 46% dry AKD (Aquapel J215 by Ashland) [0159] 8% Glyoxal (TSI Cartabond by Clariant).

[0160] The resulting coated substrate had a basis weight of 44 g/m.sup.2. This coated substrate was compared with crepe paper of the same type (100/39 g/m.sup.2 Master Tape Classic) treated with an SBR-type of latex (XZ 97235.00 by Styron) and with a 4 g/m.sup.2 acrylic release agent (Primal R-550 by Dow).

[0161] The following comparative table summarizes the mechanical properties that were measured under dry and wet conditions and shows the results:

TABLE-US-00001 TABLE 1 Comparative test 39 g/m.sup.2 Master 39 g/m.sup.2 Master tape 100 + 10 g/m.sup.2 tape 100 + 5 g/m.sup.2 SBR-type latex + PVA + AKD + 4 g/m.sup.2 acrylic Glyoxal release agent Basis weight (g/m.sup.2) 44 53 dry MD tensile strength 2.37-11.6 2.72-13 (kN/m) - elongation (%) dry CD tensile strength (kN/m) 1.23 1.22 wet MD tensile strength (kN/m) 1.2 1.32 wet CD tensile strength (kN/m) 0.59 0.5 60 sec Cobb (g/m.sup.2) 13 12 Peel strength (N/5 cm) 5.8 7.6

2: Release Test

[0162] A sheet of 60 g/m.sup.2 crepe paper was coated with various aqueous compositions using size press treatment. The dry deposition of these compositions was between 6 and 7 g/m.sup.2.

[0163] The aqueous compositions included: [0164] PVA (Moviol 4/98) (or starch Perfectamyl A4692), [0165] AKD (Aquapel J215 by Ashland) [0166] Glyoxal (CAS No. 107-22-2) (Cartabond TSI by Clariant) [0167] Water.

[0168] The FINAT F 1 test was applied. This test assesses the adaptation of a release substrate to rolling by using a PSA-type adhesive.

[0169] Sample 1: A piece of a commercial masking tape (COTEKA of Bricomarch, 5 cm width) was applied onto the release face of another piece of COTEKA tape using a 10 kg roller. The peel strengths were measured at a speed of 300 mm/min and an angle of 180.

[0170] PVA/AKD70/30 sample: A piece of commercial masking tape (COTEKA by Bricomarch, 5 cm width) was applied using a 10 kg roller on the side of a piece of crepe paper coated with the composition of the invention composed of 70 parts PVA to 30 parts AKD (or 64.4% PVA, 27.6% AKD, and 8% glyoxal by weight).

[0171] PVA/AKD60/40 sample: A piece of commercial masking tape (COTEKA by Bricomarch, 5 cm width) was applied using a 10 kg roller on the side of a piece of crepe paper coated with the composition of the invention composed of 60 parts PVA to 40 parts AKD (or 55.2% PVA, 36.8% AKD, and 8% glyoxal by weight).

[0172] PVA/AKD50/50 sample: A piece of commercial masking tape (COTEKA by Bricomarch, 5 cm width) was applied using a 10 kg roller on the side of a piece of crepe paper coated with the composition of the invention composed of 50 parts PVA to 50 parts AKD (or 46% PVA, 46% AKD and 8% glyoxal, by weight).

TABLE-US-00002 TABLE 2 Release test: Peel Strengths per FINIAT FTM 1 Peel strength (N/5 cm) Sample 1 (COTEKA) 7.24 PVA/AKD - 70/30 sample 8.26 PVA/AKD - 60/40 sample 7.08 PVA/AKD - 50/50 sample 5.87

[0173] It was noted that the peel strengths of the invention were on par with those of the commercial product, between 5 to 8 N/5 cm, and they varied according to the amount of AKD introduced into the mixture. The greater the amount of AKD in the mixture, the lower the peel strength. This shows the release property of the alkyl chains present within the AKD.

3: FINAT F 11 TestSubsequent Adhesion

[0174] The subsequent adhesion release is the force required at a given speed and angle to tear a tape coated with an adhesive adhered to a standard test plate, this tape having previously been in contact with the side of a substrate of the same type coated with a release agent under specific temperature and humidity conditions.

[0175] The aim of this test is to measure the possible transfer of the release agent into the adhesive layer.

[0176] The percentage of subsequent adhesion is expressed as the ratio between the measured adhesion compared with the adhesion obtained by a similar control tape which was not in contact with a substrate coated with a release agent. The adhesion value of the control tape was measured at 10.97 N/5 cm.

TABLE-US-00003 TABLE 3 FINAT FTM 11 test - subsequent adhesion Adhesion strength (N/5 cm) % Loss/Gain Sample 1 (COTEKA) 10.52 4.1% PVA/AKD - 70/30 sample 10.43 4.9% PVA/AKD - 60/40 sample 10.45 4.7% PVA/AKD - 50/50 sample 9.91 9.6%

[0177] The amount of loss of adhesion strength of substrates related to the invention was similar to the commercial product. There is therefore little or no transfer of AKD into the adhesive.

4: Peel Strength After Pressure Aging Test (70 g/cm.SUP.2.) at Room Temperature in Accordance with the FINAT FM 10 Test

[0178] A commercial masking tape (COTEKA by Bricomarch, 5 cm width) was applied on the different biodegradable substrates and on COTEKA tapes using a 10 kg roller under the same conditions as Example 2. The samples were pressurized (70 g/cm.sup.2) at room temperature (23 C. and 50% humidity) for 20 hours. They were then kept for at least 4 hours at 23 C. and 50% relative humidity. The peel strengths were measured at a speed of 300 mm/min and an angle of 180FINAT FM1 test.

TABLE-US-00004 TABLE 4 Peel strength after pressure aging test (70 g/cm.sup.2) at room temperature in accordance with the FINAT FM 10 test Peel strength (N/5 cm) % Loss/ Sample 1 2 3 Average Gain Sample 1 (COTEKA) 7.12 7.23 6.88 7.08 2.26 PVA/AKD - 70/30 sample 7.57 7.31 7.56 7.48 9.41 PVA/AKD - 60/40 sample 7.67 6.78 6.72 7.06 0.28 PVA/AKD - 50/50 sample 5.63 5.63 5.88 5.71 2.61

[0179] The values were compared with the values of Example 2 (Peel strength before the aging test). It was noted that the change in strength of both the commercial product and the coated substrate was low (loss between 2 and 9%) and therefore the peel strengths were stable over time under pressure at room temperature.

5: FINAT F 11 TestSubsequent Adhesion After Aging at Room Temperature

[0180] Subsequent adhesion release is the force at a given speed and angle required to tear a tape coated with an adhesive adhered to a standard test plate, this tape having previously been in contact with the side of a substrate of the same type coated with a release agent under specific temperature and humidity conditions.

[0181] The percentage of subsequent adhesion is expressed as the ratio between the adhesion measured compared to the adhesion obtained by a similar control tape which was not in contact with a substrate coated with a release agent. The adhesion value of the control tape was measured at 10.97 N/5 cm.

TABLE-US-00005 TABLE 5 FINAT FTM 11 test - subsequent adhesion after aging at room temperature Adhesion strength (N/5 cm) % Loss/Gain Sample 1 (COTEKA) 10.02 8.6 PVA/AKD - 70/30 sample 10.41 5.1 PVA/AKD - 60/40 sample 9.84 10.3 PVA/AKD - 50/50 sample 9.41 14.22

[0182] The amount of loss of adhesion strength of coated substrates related to the invention was similar to the commercial product. There is therefore little or no transfer of AKD into the adhesive. The prototype with 50 parts of AKD shows a lower value, involving a slight potential migration of AKD into the adhesive.

6: Peel Strength After Pressure Aging Test (70 g/cm.SUP.2.) at 70 C. in Accordance with the FINAT FM 10 Test

[0183] A commercial masking tape (COTEKA by Bricomarch, 5 cm width) was applied on the different types of crepe paper and COTEKA tapes using a 10 kg roller under the same conditions as Example 2. The samples were pressurized (70 g/cm.sup.2) at 70 C. for 20 hours. They were then kept for at least 4 hours at 23 C. and 50% relative humidity. The peel strengths were measured at a speed of 300 mm/min and an angle of 180FINAT FM1 test.

TABLE-US-00006 TABLE 6 Peel strength after pressure aging test (70 g/cm.sup.2) at 70 C. in accordance with the FINAT FM 10 test Peel strength (N/5 cm) % Loss/Gain Sample 1 (COTEKA) 8.26 14.09 PVA/AKD - 70/30 sample 9.89 19.78 PVA/AKD - 60/40 sample 10.68 50.92 PVA/AKD - 50/50 sample 9.11 55.28

[0184] The change in the peel strengths of the biodegradable substrates in accordance with the invention with 30 parts of AKD shows a change in its release properties similar to the commercial product (15-20%). In contrast, the other two biodegradable substrates samples in accordance with the invention show quite a significant change (+50%).

7: FINAT F 11 TestSubsequent Adhesion After Aging at 70 C.

[0185] The subsequent adhesion release is the force required at a given speed and angle to tear a tape coated with an adhesive adhered to a standard test plate, this tape having previously been in contact with the side of a substrate of the same type coated with a release agent under specific temperature and humidity conditions.

[0186] The percentage of subsequent adhesion is expressed as the ratio between the measured adhesion compared to the adhesion obtained by a similar control tape which was not in contact with a substrate coated with a release agent. The adhesion value of the control tape was measured at 10.97 N/5 cm.

TABLE-US-00007 TABLE 7 FINAT FTM 11 test - subsequent adhesion after aging at 70 C. Adhesion strength (N/5 cm) % Loss/Gain Sample 1 (COTEKA) 9.76 11 PVA/AKD - 70/30 sample 10.01 8.7 PVA/AKD - 60/40 sample 9.21 16 PVA/AKD - 50/50 sample 7.43 32.2

[0187] The amount of loss of adhesion strength in biodegradable substrates with 30 parts of AKD was similar to the commercial product. There is therefore little or no transfer of AKD into the adhesive for this prototype. In contrast, the prototype with 50 parts of AKD shows a much lower value (loss of adhesion strength of more than 30%) involving a potential migration of AKD into the adhesive.

8: Peel Strength After Aging (7 days) at High Temperature (65 C.) and High Humidity (85% Relative Humidity)AFERA #4003 (EN 12024) Test

[0188] A commercial masking tape (COTEKA by Bricomarch, 5 cm width) was applied to the different biodegradable substrates in accordance with the invention and to itself using a 10 kg roller. The samples were then kept as such (without pressure) in a climate simulation chamber at 65 C. and 85% humidity for 7 days (AFERA # 4003 test). The peel strengths were measured at a speed of 300 mm/min and an angle of 180.

TABLE-US-00008 TABLE 8 Peel strength after aging (7 days) at high temperature (65 C.) and high humidity (85% relative humidity) - AFERA #4003 (EN 12024) test Initial peel Peel strength strength after aging % Sample (N/5 cm) (N/5 cm) change Sample 1 (COTEKA) 7.24 9.99 +38% PVA/AKD - 70/30 sample 8.26 9.95 +20% PVA/AKD - 60/40 sample 7.08 9.37 +32% PVA/AKD - 50/50 sample 5.87 8.34 +42%

[0189] It may therefore be noted that the different biodegradable substrates in accordance with the present invention perform similarly or better (more stable peel strength for the PVA/AKD70/30 mixture) than the commercial product (i.e.: COTEKA).

II/2.SUP.d .Embodiment: Flat Back Paper as a Substrate

Release Test

[0190] A sheet of 62 g/m.sup.2 flat back paper was coated with various aqueous compositions using size press treatment. The dry deposition of these compositions was 8 g/m.sup.2.

[0191] The aqueous compositions included: [0192] PVA (Moviol 4/98) (or starch Perfectamyl A4692), [0193] AKD (Aquapel J215 by Ashland) [0194] Glyoxal (CAS No. 107-22-2) (Cartabond TSI by Clariant) [0195] Water.

[0196] The FINAT F 1 test was applied. This test assesses the adaptation of a biodegradable substrate to rolling by using a PSA-type adhesive.

[0197] Sample 1: A piece of a commercial masking tape (COTEKA of Bricomarch, 5 cm width) was applied onto the release face of another piece of COTEKA tape using a 10 kg roller. The peel strengths were measured at a speed of 300 mm/min and an angle of 180.

[0198] PVA/AKD70/30 sample: A piece of commercial masking tape (COTEKA by Bricomarch, 5 cm width) was applied using a 10 kg roller on the side of a piece of a flat back paper (AHLSTROM Mastertape DELICATE 400-62 g/m.sup.2) coated with 8 g/m.sup.2 of the composition of the invention composed of 70 parts PVA to 30 parts AKD (or 64.4% PVA, 27.6% AKD, and 8% glyoxal by weight).

[0199] Starch/AKD70/30 sample: A piece of commercial masking tape (COTEKA by Bricomarch, 5 cm width) was applied using a 10 kg roller on the side of a piece of a flat back paper ((AHLSTROM Mastertape DELICATE 400-62 g/m.sup.2) coated with 8 g/m.sup.2 of the composition of the invention composed of 70 parts Starch to 30 parts AKD (or 64.4% starch, 27.6% AKD, and 8% glyoxal by weight).

TABLE-US-00009 TABLE 9 Release test Peel Strengths per FINIAT FTM1 Peel strength (N/5 cm) Sample 1 (COTEKA) 7.24 PVA/AKD - 70/30 sample 6.89 Starch/AKD - 70/30 sample 5.956

[0200] It was noted that the peel strengths of the invention were on par with those of the commercial product, between 5 to 8 N/5 cm. This shows the release property of the alkyl chains present in AKD.

III/Paint Test

[0201] The aim of paint test is to see the resistance of masking tape against paint. Especially, the migration of the paint on the edges (paint back) is observed. This test has been developed by the Applicant.

1/Preparation of the Sample

[0202] Sample 1: A commercial masking tape (COTEKA by Bricomarch, 5 cm width).

[0203] Sample 2: A sheet of crepe paper for masking tape (Mastertape Smart line 300) with a basis weight of 55 g/m.sup.2 was treated by size press at machine scale with an aqueous mixture PVA/AKD (50/50 in parts or 46% PVA, 46% AKD and 8% glyoxal by weight), with a dry weight of 5 g/m.sup.2.

[0204] Sample 3: A sheet of flat back paper ((AHLSTROM Mastertape DELICATE 400-62 g/m.sup.2)) with a basis weight of 62 g/m.sup.2 was treated by size press at lab scale with an aqueous mixture PVA/AKD (70/30 in parts or 64.4% PVA, 27.6% AKD and 8% glyoxal by weight), with a dry weight of 8 g/m2.

[0205] Sample 2 and 3 are then coated on the smoother side with 25 to 30 g/m.sup.2 of an adhesive (DowCorning Binder ROBOND PS9005 (MS: 57%)).

2/Application of the Paint

[0206] Sample 1 and samples 2 and 3 (these later being cut in band of 5 cm width) are applied each on a 13 cm by 13 cm transparent glass plate. 3.5 to 3.7 g of paint is applied on all the surface of the plate.

[0207] The plates are left to dry at least 4 hours.

3/Measurement of the Migration of the Paint

[0208] Each plate is turned and a transparent mesh having holes of 1 mm is applied against the plate. Surface of migration is then calculated by counting the number of holes filed with the paint/cm. lower is the surface of paint, lower is the migration and better is the marking tape.

4/Results

[0209] FIG. 1: Sample 1 corresponds to COTEKA. The migration is 10.6 mm.sup.2/cm.

[0210] FIG. 2: sample 2 of the invention. The migration is 0.6 mm.sup.2/cm.

[0211] FIG. 3: sample 3 of the invention. The migration is 0.12 mm.sup.2/cm.

IV/Biodegradability Test

[0212] To evaluate biodegradability of coated biodegradable substrates in accordance with the present invention, two samples were prepared.

1/Sample Preparation and Characterization

[0213] Inventive example 1 (EX1), Inventive example 2 (EX2): The base paper used in EX1 and EX2 is cellulose fiber-based. In particular, the base paper comprises a mixture of Joutseno pulp from Mets Fibre (i.e. a Northern Bleached Softwood Kraft (NBSK) pulp having long fibers), and a eucalyptus (EUC) pulp from Suzano (i.e., a bleached EUC hardwood pulp having short fibers).

TABLE-US-00010 TABLE 10 Biodegradability test: Base Paper characterization EX1 EX2 Composition 75% Joutseno NBSK pulp 60% Joutseno NBSK pulp 25% Suzano EUC pulp 40% Suzano EUC pulp basis weight, 49 g/m2 44 g/m2 gsm Creping flat paper delicate configuration flat configuration paper

[0214] The base papers were treated on one side with the Release Composition using size-press.

TABLE-US-00011 TABLE 11 Biodegradability test: Substrate characterization EX1 EX2 Release composition. 65.4% Starch 28% AKD (Aquapel J215) 6.5% Glyoxal (Cartabond TSI) Dry weight ratio 70:30 Starch:AKD Dry weight ratio 1:10 crosslinker:starch Thickness under pressure (ISO 76 m 75 m 534, 1 bar) Bulk or density 1.55 1.71 Coat weight, gsm 6-8 g/m2 4-5 g/m2 dry MD tensile strength (kN/m) 3.9 5.15 dry CD tensile strength (kN/m) 2.23 2.02 wet MD tensile strength (kN/m) 0.83 1.51 wet CD tensile strength (kN/m) 0.47 0.68 Dry MD elongation (%) 2% 2.48% Dry CD elongation (%) 4.761% 5.373% Wet MD elongation (%) 3.92% 4.697% Wet CD elongation (%) 5.707% 7.261% Bendsten porosity 1.47 kPa 5.1 29 (ml/min) 60 sec Cobb value, gsm 15 gsm 14.03 gsm

[0215] Peel strength values of the biodegradable substrates are suitably <20N/5 cm, preferably <10N/5 cm, and most preferably in the range of 5-8N/5 cm by following the FINIAT F1 test protocol as outlined in Example 2: release test. It is appreciated that different reference tapes, peel angles, peel speeds, and the like may affect the peel strength values.

2/Biodegradability Tests

[0216] The inventive specimens EX1 and EX2 were evaluated for biodegradability.

[0217] The aerobic biodegradation of EX1 and EX2 was evaluated by controlled composting test according to ISO 14855-1 (2012). Incubation temperature was kept at 58 C. and the test duration was 45 days. The controlled composting biodegradation test is an optimized simulation of an intensive aerobic composting process where the biodegradability of a test item under dry, aerobic conditions is determined.

[0218] The test is performed using a test sample and a suitable reference item. In the test procedure, the test item is mixed with inoculum (stabilized and mature compost derived from the organic solid waste), and introduced into static reactor vessels where it is intensively composted under optimum oxygen, temperature and moisture conditions. Through biodegradation, solid carbon of the test compound is converted and CO.sub.2 is produced. Each individual reactor is continuously analyzed on regular intervals for CO.sub.2 and O.sub.2 concentration and flow rate. Using these measurements, rate of CO.sub.2 production and cumulative total CO.sub.2 production can be determined.

[0219] The percentage of biodegradation is determined as the percentage of solid carbon of the test compound that is converted to gaseous, mineral carbon under the form of CO.sub.2. For the reference item and the test items, the absolute biodegradation percentage is determined based on carbon measured from CO.sub.2 production as a percentage of total carbon in the item (CO.sub.2 quantified with mass).

[0220] The test is considered valid if after 45 days the biodegradation percentage of the reference item is more than 70% and if the standard deviation of the biodegradation percentage of the reference item is less than 20% at the end of the test. Both criteria were met successfully.

Results

[0221]

TABLE-US-00012 TABLE 12 Biodegradation at 10 and 45 days Reference item (cellulose) EX1 EX2 Biodegradation at 10 56.8% Approx. 60% days Biodegradation at 45 74.8% 3.7% 71.6% 4.7% 77.1% 2.6% days (end of test)

[0222] In addition to absolute biodegradation percentage, relative biodegradation percentage of the test items can be determined on a relative basis with respect to the reference item. Biodegradation relative to reference item was 95.7% and 103.1% for EX1 and EX2, respectively.

[0223] European standard EN 13432 (2000) specifies that a biodegradable material, within the maximum test period of 180 days, the percentage of biodegradation is at least 90% in total or 90% of the maximum degradation of a suitable reference item after a plateau has been reached for both reference and test item.

[0224] Test samples EX1 and EX2 fulfill the biodegradation requirement of EN 13432 within 45 days of testing, thus it can be concluded that the test samples are biodegradable according to European standard EN 13432 (2000). As mentioned, the biodegradation levels of EX1 and EX2 relative to reference cellulose determined per ISO 14855-1 (2012) were 95.7% and 103.1% for EX1 and EX2, respectively, at 45 days duration.