PROCESS FOR THE PRODUCTION OF A FORMULATION CONTAINING POLY(LACTIC ACID) AND ALIPHATIC AND/OR AROMATIC POLYESTERS AND PRODUCTS USING IT

Abstract

The invention presented in this document relates to processes for the preparation of a formulation containing poly(lactic acid) (PLA) and aliphatic and/or aromatic polyesters which plasticize it, and its use in monofilaments and films. The presence of polyesters does not remove the biodegradability and composting characteristics of the raw materials used in the formulation. The invention also concerns products that use the formulation.

Claims

1. Process for the preparation of a granulated plasticizing formulation characterized by comprising the following steps: a) Preparation of a mixture of 46% to 94% by mass of PLA and 6% to 54% by mass of an aliphatic and/or aromatic polyester and other agents; b) Feeding of said mixture obtained in (a) an extruder with extrusion temperatures ranging from 130° C. to 190° C. and elongation in a ratio ranging from a minimum of 1:5 to a maximum of 1:12 with an intermediate thermal treatment process with temperatures ranging from 85° C. to 120° C.

2. Process according to claim 1 characterized by said mixture containing 70% by mass of PLA.

3. Procedure according to claim 1 characterized by said mixture containing 30% by mass of an aliphatic and/or aromatic polyester and other agents.

4. Raffia-tape-type product characterized by being obtained from the formulation obtained in claim 1, and having a yield from 50 to 3,000 m/kg, a meterage from 321 to 1063.0 m/kg, an ultimate tensile strength from 13.6 to 75.0 kgf, an elongation from 6.1% to 20.2% and a tenacity from 0.0015146 to 0.0081931 gf/(m/kg).

5. Process for the production of the raffia-tape-type product claimed in claim 4, characterized by comprising the following steps: a) Feeding of the film obtained with the granulated plasticizing formulation of claim 5 in a flat-lip extruder with an extrusion temperature of 135° C. to 190° C., b) Heat treatment of the film with a temperature of 95° C. to 115° C., c) Elongation of the film, with an elongation ratio of 1:5 to 1:10, preferably 1:6, d) Division of the film into several tapes, e) Fibrillation of the tapes in a fibrillator, f) Collection of the tape in reels.

6. Monofilament-type product characterized by being obtained from the formulation obtained in claim 1.

7. Product according to claim 6, characterized by having a yield from 3.000 to 60.000 m/kg.

8. Process for the production of the monofilament-type product claimed in claim 6, characterized by comprising the following steps: a) Feeding of the monofilament obtained with the granulated plasticizing formulation of claim 5 in a monofilament extruder in a spinneret with an extrusion temperature of 135° C. to 180° C.; b) Wet heat treatment of the monofilament, with a temperature of 85° C. to 105° C., preferably 95° C., followed by a second dry heat treatment, with a temperature of 100° C. to 120° C., preferably 112° C., between drawing rollers; c) Monofilament elongation, in an elongation ratio of 1:5 to 1:12, preferably 1:7; d) Collection of the monofilament in reels.

9. Use of a product, as defined in claim 4, characterized by its use in the manufacturing of, for example, but not limited to, yarns, ropes, meshes, and nets.

10. Use of a product, as defined in claim 6, characterized by its use in the manufacturing of, for example, but not limited to, yarns, ropes, meshes, and nets.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0024] “Raffia tape” means tape or film of polymeric material capable of fibrillation after further processing.

[0025] “Monofilament” means continuous filament usually with a circular section with a diameter greater than 100 μm.

[0026] “Yarn” means the twisted entity composed of monofilaments, fibers or fibrillated films (raffia tape) joined together by twisting.

[0027] “Cord” means the product obtained by twisting two or more yarns together.

[0028] “Rope” means the product obtained when three or more strands are twisted or braided or placed in a parallel construction to provide a composite article of cordage larger than 4 mm in diameter.

[0029] “Yield” means the textile units of measurement establishing the ratio of the length of the final material and its corresponding mass. E.g., denier, m/kg, tex, among others.

[0030] The abbreviation “gf/(m/kg)” means the unit of measurement of tenacity whose meaning is: grams-force per meter per kilogram.

[0031] In the invention described in this document, a biopolymer was developed using a mixture of poly(lactic acid) (PLA) and polyester-type polymers. The polymers that accompany the PLA, together with other agents commonly used industrially in monofilament and film processing, are present in this product in a percentage that can vary between 6% and 54%. The developed mixture as well as the processing adjusted to it enable the fluidity index and the properties of the resulting product to be ideal for film and monofilament extrusion.

[0032] Additionally, this invention presents the use of aliphatic and/or aromatic polyesters capable of plasticizing the PLA, as well as the extrusion process for the production of a material with good mechanical properties necessary for the production of, for example, but not limited to, monofilament, yarns, ropes and cables, cord, meshes and films, and raffia tape.

[0033] The incorporation of aliphatic and/or aromatic polyesters, as well as other additives, is done in a ratio between 6% and 54%, more specifically between 25% and 35%, with the remaining material being PLA.

[0034] The processing of the mixture is performed in one of the following ways: [0035] 1) The biopolymer composed of PLA and aliphatic and/or aromatic polyesters and other agents is processed in a flat-lip extruder with extrusion temperatures ranging from a minimum of 135° C. to a maximum of 190° C., and the film is divided into several tapes, according to the final desired yield. The tapes are stretched in an elongation ratio ranging from a minimum of 1:5 to a maximum of 1:10, preferably 1:6. This operation is intermediated by a heat treatment process that can vary from a minimum of 85° C. to a maximum of 105° C., preferably 95° C. Subsequently, all the tapes are fibrillated in a fibrillator and collected in reels or tubes that can have multiple formats. [0036] 2) The biopolymer composed of PLA and aliphatic and/or aromatic polyesters and other agents is processed in a monofilament extruder in a spinneret, with extrusion temperatures ranging from a minimum of 135° C. to a maximum of 180° C., with the number of monofilaments and their m/kg varying, and having cylindrical or oval shapes. The monofilaments obtained are then stretched in an elongation ratio ranging from a minimum of 1:5 to a maximum of 1:12. This operation is intermediated by a heat treatment process involving two phases, one of water/steam, which may range from a minimum of 90° C. to a maximum of 100° C. and the next of heat, with a minimum of 100° C. and a maximum of 120° C. Subsequently, all monofilaments are collected in reels or tubes that can have multiple formats.

OBJECTS OF THE INVENTION

[0037] Additionally, the object of this invention consists of the products using a formulation composed of a mixture of PLA with aliphatic and/or aromatic polyesters and other various agents, and the subsequent process for their transformation into monofilaments and films, applicable to the manufacture of yarns, ropes, meshes and nets: [0038] a) Preparation of a mixture of 46% to 94%, preferably 70%, by mass, of PLA, and 6% to 54%, preferably 30%, by mass, of an aliphatic and/or aromatic polyester and other agents; [0039] b) Production of monofilaments with the material obtained in (a), using specific temperature parameters and processing elongation ratios mentioned in the examples; [0040] c) Production of film with the material obtained in (a), using specific temperature parameters and processing elongation ratios mentioned in the examples.

[0041] Examples of the objects of the invention are, for example, but not limited to, the final products obtained by processing a mixture of PLA with aliphatic and/or aromatic polyesters and other agents: [0042] Raffia tape, with a yield of 50 to 3,000 m/kg, obtained with the extrusion of a stretched film, fibrillated or not, which enables the production of twisted yarns and stranded cord or rope, with a diameter between 4 mm and 160 mm, up to thirty-six cables and also meshes with a weight between 20 and 310 g/m.sup.2, woven on a circular flat loom; [0043] Monofilament, with a yield from 3,000 to 60,000 m/kg, obtained by the extrusion of the biopolymer, subject to specific heat treatment, which enables the production of twisted and braided yarns with a variation and caliber between 0.005 m and 0.16 m and with a minimum of one cable up to a maximum of thirty-six cables or braids; [0044] Monofilament meshes, produced by a circular flat loom weaving process, with a minimum weight of 20 g/m.sup.2 and a maximum weight of 310 g/m.sup.2. The widths ranged from 0.5 to 6 m with the length being the one desired for the final application; [0045] Nets made of twisted or braided monofilaments with minimum and maximum mesh lengths between knots of 2.08 m and 12 m, respectively, with the possibility of a mesh width of 500 meshes, with the length being the one desired.

[0046] Below are a few products and their production process.

[0047] A few formulations were tested and processed to understand how the quantity of aliphatic and/or aromatic polyesters influences the processing of the material.

[0048] The first sample is a mixture of 50% PLA with 50% aliphatic and/or aromatic polyester and other agents.

[0049] The second sample is a mixture of 65% PLA with 35% aliphatic and/or aromatic polyester and other agents.

[0050] The third sample is a mixture of 75% PLA with 25% aliphatic and/or aromatic polyester and other agents.

[0051] The fourth and final sample is a mixture of 70% PLA with 30% aliphatic and/or aromatic polyester and other agents and was considered the mixture with the ideal ratios.

EXAMPLES

Example 1: 50%-PLA Raffia-Tape Extrusion

[0052] A 50%-PLA film (Tg=55-60° C., Tm=145-160° C.) was extruded with 50% aliphatic and/or aromatic polyesters and other agents, with extruder temperatures between 155° C. and 185° C. and then cut into tapes. These tapes were then elongated, with a maximum ratio of 1:6, in a single elongation process at a temperature of 90° C.

[0053] Fibrillated tapes of 400 and 1,000 m/kg and twisted yarn were obtained and tested in a laboratory.

TABLE-US-00001 Ultimate Tenacity Meterage tensile Elongation (gf/ Torsion Sample (m/kg) strength (kgf) (%) (m/kg)) (turns/m) Raffia 481.1 33.4 13.5 0.0036999 NA tape 903.9 18.5 20.2 0.0020467 NA Twisted 508.9 25.0 11.0 0.0027707 28 yarn 1063.0 13.6 10.8 0.0015146 40

[0054] All resistance measurements were carried out with a reference length of 0.25 m in a room with controlled temperature and humidity as defined by ISO 139:2005, i.e., temperature of 20.0° C.±2.0° C. and humidity of 65.0%±4.0%.

Example 2: 65%-PLA Raffia-Tape Extrusion

[0055] A 65%-PLA film (Tg=55-60° C., Tm=145-160° C.) was extruded with 35% aliphatic and/or aromatic polyesters and other agents, with extruder temperatures between 155° C. and 185° C. and then cut into tapes. These tapes were then elongated, with a maximum ratio of 1:6.7, in a single elongation process at a temperature of 90° C.

[0056] Fibrillated tapes of 500 m/kg and twisted yarn were obtained and tested in a laboratory.

TABLE-US-00002 Ultimate Tenacity Meterage tensile Elongation (gf/ Torsion Sample (m/kg) strength (kgf) (%) (m/kg)) (turns/m) Raffia 587.1 21.8 6.1 0.0024187 NA tape Twisted 575.4 28.5 10.6 0.0031630 28 yarn

[0057] All resistance measurements were carried out with a reference length of 0.25 m in a room with controlled temperature and humidity as defined by ISO 139:2005, i.e., temperature of 20.0° C.±2.0° C. and humidity of 65.0%±4.0%.

Example 3: 75%-PLA Raffia-Tape Extrusion

Trial 1

[0058] The extrusion of a 75%-PLA film (Tg=55-60° C., Tm=145-160° C.) was tested with 25% aliphatic and/or aromatic polyesters and other agents, with extrusion temperatures between 155° C. and 185° C., and cut into tapes. The resulting tapes were elongated with a 1:7 ratio at a temperature of 90° C.

[0059] Fibrillated tapes of 500 m/kg and twisted yarn were obtained and tested in a laboratory.

TABLE-US-00003 Ultimate Tenacity Meterage tensile Elongation (gf/ Torsion Sample (m/kg) strength (kgf) (%) (m/kg)) (turns/m) Raffia 449.2 34.1 8.6 0.0037845 NA tape Twisted 440.9 40.5 11.4 0.0044908 28 yarn

[0060] All resistance measurements were carried out with a reference length of 0.25 m in a room with controlled temperature and humidity as defined by ISO 139:2005, i.e., temperature of 20.0° C.±2.0° C. and humidity of 65.0%±4.0%.

Trial 2

[0061] The extrusion of a 75%-PLA film (Tg=55-60° C., Tm=145-160° C.) was tested with 25% aliphatic and/or aromatic polyesters and other agents, with extrusion temperatures between 140° C. and 177° C., and cut into tapes. The resulting tapes were elongated with a 1:8.2 ratio at a temperature of 102° C.

[0062] Fibrillated tapes of 350 m/kg and twisted yarn were obtained and tested in a laboratory.

TABLE-US-00004 Ultimate Knot ultimate Meterage tensile Elongation Tenacity Torsion tensile Sample (m/kg) strength (kgf) (%) (gf/(m/kg)) (turns/m) strength (kgf) Raffia 345.5 67.4 12.4 0.0074674 NA NA tape Twisted 333.0 58.8 12.3 0.0074775 30 33.3 yarn

[0063] All resistance measurements were carried out with a reference length of 0.25 m in a room with controlled temperature and humidity as defined by ISO 139:2005, i.e., temperature of 20.0° C.±2.0° C. and humidity of 65.0%±4.0%.

Trial 3

[0064] The extrusion of a 75%-PLA film (Tg=55-60° C., Tm=145-160° C.) was tested with 25% aliphatic and/or aromatic polyesters and other agents, with extrusion temperatures between 140° C. and 177° C., and cut into tapes. The resulting tapes were elongated with a 1:8.5 ratio at a temperature of 90° C.

[0065] Fibrillated tapes of 400 m/kg and twisted yarn were obtained and tested in a laboratory.

TABLE-US-00005 Ultimate Knot ultimate Meterage tensile Elongation Tenacity Torsion tensile Sample (m/kg) strength (kgf) (%) (gf/(m/kg)) (turns/m) strength (kgf) Raffia 321.0 75.0 12.5 0.0081931 NA NA tape Twisted 400.0 43.9 10.6 0.0048750 30 23.0 yarn

[0066] All resistance measurements were carried out with a reference length of 0.25 m in a room with controlled temperature and humidity as defined by ISO 139:2005, i.e., temperature of 20.0° C.±2.0° C. and humidity of 65.0%±4.0%.

Trial 4

[0067] The extrusion of a 75%-PLA film (Tg=55-60° C., Tm=145-160° C.) was tested with 25% aliphatic and/or aromatic polyesters and other agents, with extrusion temperatures between 140° C. and 189° C., and cut into tapes. The resulting tapes were elongated with a 1:8 ratio at a temperature of 100° C.

[0068] Fibrillated tapes of 400 and 800 m/kg and twisted yarn of 400, 600 and 800 m/kg were obtained and tested in a laboratory.

TABLE-US-00006 Ultimate Knot ultimate Meterage tensile Elongation Tenacity Torsion tensile Sample (m/kg) strength (kgf) (%) (gf/(m/kg)) (turns/m) strength (kgf) Raffia 370.0 62.8 13.5 0.0069730 NA NA tape 786.4 32.2 13.1 0.0035732 NA NA Twisted 372.0 56.5 13.5 0.0062903 30 29.3 yarn 644.0 39.1 12.9 0.0043478 33 20.1 836.0 28.1 11.1 0.0031220 33 15.4

[0069] All resistance measurements were carried out with a reference length of 0.25 m in a room with controlled temperature and humidity as defined by ISO 139:2005, i.e., temperature of 20.0° C.±2.0° C. and humidity of 65.0%±4.0%.

Trial 5

[0070] A 75%-PLA film (Tg=55-60° C., Tm=145-160° C.) was extruded with 25% aliphatic and/or aromatic polyesters and other agents, with extruder temperatures between 140° C. and 183° C. and then cut into tapes. These tapes were then elongated, with a maximum ratio of 1:6.8, in a single elongation process at a temperature of 101° C.

[0071] Fibrillated tapes of 400, 600 and 800 m/kg and twisted yarn of 800 m/kg were obtained and tested in a laboratory.

TABLE-US-00007 Ultimate Knot ultimate Meterage tensile Elongation Tenacity Torsion tensile Sample (m/kg) strength (kgf) (%) (gf/(m/kg)) (turns/m) strength (kgf) Raffia 445.9 38.6 7.1 0.0042835 NA NA tape 637.3 27.2 7.5 0.0030127 NA NA 843.5 28.4 13.0 0.0031535 NA NA Twisted 838.0 19.9 9.21 0.0022076 11.2 yarn

[0072] All resistance measurements were carried out with a reference length of 0.25 m in a room with controlled temperature and humidity as defined by ISO 139:2005, i.e., temperature of 20.0° C.±2.0° C. and humidity of 65.0%±4.0%.

Example 4: 70%-PLA Raffia-Tape Extrusion

Trial 1

[0073] A 70%-PLA film (Tg=55-60° C., Tm=145-160° C.) was extruded with 30% aliphatic and/or aromatic polyesters and other agents, with extruder temperatures between 140° C. and 180° C. and then cut into tapes. These tapes were then elongated, with a maximum ratio of 1:8.5, in a single elongation process at a temperature of 102° C.

[0074] Fibrillated tapes of 400 and 700 m/kg and twisted yarn were obtained and tested in a laboratory.

TABLE-US-00008 Ultimate Knot ultimate Meterage tensile Elongation Tenacity Torsion tensile Sample (m/kg) strength (kgf) (%) (gf/(m/kg)) (turns/m) strength (kgf) Raffia 373.9 64.5 13.4 0.0071409 NA NA tape 732.6 35.0 13.1 0.0038766 NA NA Twisted 367.0 58.3 13.0 0.0064850 30 27.6 yarn 731.0 28.0 10.0 0.0031053 33 15.6

[0075] All resistance measurements were carried out with a reference length of 0.25 m in a room with controlled temperature and humidity as defined by ISO 139:2005, i.e., temperature of 20.0° C.±2.0° C. and humidity of 65.0%±4.0%.

Trial 2

[0076] A 70%-PLA film (Tg=55-60° C., Tm=145-160° C.) was extruded with 30% aliphatic and/or aromatic polyesters and other agents, with extruder temperatures between 140° C. and 183° C. and then cut into tapes. These tapes were then elongated, with a maximum ratio of 1:6.8, in a single elongation process at a temperature of 101° C.

[0077] Fibrillated tapes of 400, 600 and 800 m/kg and twisted yarn were obtained and tested in a laboratory.

TABLE-US-00009 Ultimate Knot ultimate Meterage tensile Elongation Tenacity Torsion tensile Sample (m/kg) strength (kgf) (%) (gf/(m/kg)) (turns/m) strength (kgf) Raffia 414.7 38.9 7.9 0.0043164 NA NA tape 627.1 38.8 15.2 0.0043055 NA NA 815.4 20.8 7.9 0.0023179 NA NA Twisted 409.0 36.0 9.7 0.0040098 30 23.3 yarn 609.0 27.5 8.8 0.0030542 30 16.1 812.0 19.4 8.0 0.0021552 33 12.9

[0078] All resistance measurements were carried out with a reference length of 0.25 m in a room with controlled temperature and humidity as defined by ISO 139:2005, i.e., temperature of 20.0° C.±2.0° C. and humidity of 65.0%±4.0%.

Trial 3

[0079] A 70%-PLA film (Tg=55-60° C., Tm=145-160° C.) was extruded with 30% aliphatic and/or aromatic polyesters and other agents, with extruder temperatures between 140° C. and 184° C. and then cut into tapes. These tapes were then elongated, with a maximum ratio of 1:6.6, in a single elongation process at a temperature of 96° C.

[0080] Fibrillated tapes of 500 and 600 m/kg and twisted yarn of 600 m/kg were obtained and tested in a laboratory.

TABLE-US-00010 Ultimate Knot ultimate tensile Tenacity tensile Meterage strength Elongation (gf/ strength Sample (m/kg) (kgf) (%) (m/kg)) (kgf) Raffia 503.5 36.7 9.2 0.0040715 NA tape 608.6 29.6 8.1 0.0032862 NA Twisted 588.0 33.5 11.0 0.0037245 19.8 yarn

[0081] All resistance measurements were carried out with a reference length of 0.25 m in a room with controlled temperature and humidity as defined by ISO 139:2005, i.e., temperature of 20.0° C.±2.0° C. and humidity of 65.0%±4.0%.

Example 5: 70%-PLA Monofilament Extrusion

[0082] Monofilaments of 70% PLA with 30% aliphatic and/or aromatic polyesters and other agents were extruded, with extrusion temperatures between 135° C. and 175° C. The resulting monofilaments were elongated with a 1:7 ratio at a temperature of 95° C.

[0083] Monofilament samples of 9.490 m/kg were sent for laboratory testing.

TABLE-US-00011 Meterage Ultimate tensile Elongation Tenacity Sample (m/kg) strength (kgf) (%) (gf/(m/kg)) Monofilament 8001 3.4 22.7 0.0004249

[0084] All resistance measurements were carried out with a reference length of 0.25 m in a room with controlled temperature and humidity as defined by ISO 139:2005, i.e., temperature of 20.0° C.±2.0° C. and humidity of 65.0%±4.0%.

CONCLUSIONS

[0085] From the results of the tests carried out, taking into account the environmental constraints and requirements that the market demands on similar products and also considering the processability and mechanical resistance of the final product, it is found that the best mixture of PLA and aliphatic and/or aromatic polyesters is the one containing from 65% to 75% PLA by mass.

[0086] This mixture enabled obtaining yarns with good results in tensile strength and with the lowest oscillation of values along their length.