PL249186B1 - Method of manufacturing nonwoven flowerpots for horticultural and agricultural applications using the pneumothermal method from biodegradable polymers - Google Patents

Abstract

The subject of the application is a method for manufacturing non-woven flower pots for use in horticulture and agriculture, using the pneumothermal method from biodegradable polymers, which is characterized in that the material from which the non-woven flower pots are manufactured is polylactide or bio-derived polybutylene succinate or a mixture of bio-derived polybutylene succinate with a polymer such as polyhydroxyalkanoate poly (copolymer of butylene adipate and butylene terephthalate) and a dye in the form of masterbatch or activated carbon is added in an amount of 0.1% - 10% in relation to the weight of the polymer or polymer mixture, wherein the polymer granulate dried at a temperature not exceeding 130°C, for up to 7 hours, preferably 80°C and 5 hours, is subjected to melting and plasticization in subsequent zones of the extruder with temperatures in the individual zones in the range of: 150°C-180°C, 160°C-200°C, 160°C-210°C, 170°C-210°C, 170°C-220°C, 180°C-230°C, 190°C-260°C and is extruded at a speed in the range of 20 - 50 rpm, preferably 40 rpm, then blown into fibers with air at a temperature of 200°C-260°C, flowing at a rate of 30 - 60 Nm3/h, using 45 Nm3/h from an extrusion head at a temperature of 190°C-260°C, using 220°C and collected on a mold in the form of a pot, rotating at a constant speed of 0 - 2000 rpm at a distance of 20 - 40 cm, preferably 30 cm from the extruder head, the pots are finally removed from the mold at equal time intervals of 15 to 45 seconds, preferably every 30 seconds.

Description

The subject of the invention is a method of manufacturing non-woven flower pots for use in horticulture and agriculture, using pneumo-thermal technology from bio-derivatives and biodegradable polymers.

Due to growing environmental awareness, conventional polymers used for agricultural and horticultural purposes are slowly being replaced by products made of biodegradable or compostable materials. Accordingly, there is currently increased interest in ecological solutions made from natural raw materials such as cellulose, starch, chitosan, and alginates, as well as bioplastics, i.e., synthetic polymers obtained from renewable sources, such as polylactide (PLA), polyhydroxyalkanoate (PHB), poly(butylene adipate-butylene terephthalate copolymer) (PBAT), and polybutylene succinate (PBS) and their blends (journals: Polymers, 64 (7-8), 2020, 480-486; International Journal of Molecular Sciences, 10, 2009, 3722-3742).

Currently, in plant cultivation, seedling pots are used for short periods (depending on the time required for the plant to grow). The seedlings growing in them are then transplanted into the soil, and the pot, even if used several times, must be disposed of after some time. Currently, biodegradable pots are made from biomass – peat, cellulose, and natural fibrous materials such as coconut fiber or palm fiber. Plants growing in them can be transplanted into the ground along with the pot, because the pot is made of readily biodegradable materials; its structure loosens, allowing the plant's root system to develop. An additional advantage of biodegradable pots is the reduced risk of root damage when removing the plant from the pot, if such a process is necessary.

Patent application P.442079 describes a method for producing a hybrid membrane for horticultural and agricultural applications using a nonwoven pneumatic thermal method from biobased polybutylene succinate and polylactide, using a single- or twin-screw extruder. The method involves drying the polymer granules, then feeding them into the extruder, where they are melted and plasticized. Subsequently, they are blow-extruded from the extruder head into fibers, which are discharged onto a receiver located at a specified distance from the extruder head. The resulting membranes were characterized by various parameters – thickness, mass per unit area, water vapor transmission rate (MVTR), roughness, and air permeability – using various technological parameters. The resulting nonwoven membrane could potentially be used for the production of flowerpots, but in a subsequent technological process.

U.S. Patent No. 5,523,331 describes a soil-degradable plant pot composed of a rubber composition essentially consisting of 97 to 30 parts by weight of a rubber component and 3 to 70 parts by weight of a water-soluble additive that does not bind to the rubber component. Carboxymethylcellulose, casein, and starch are listed as binders. The authors have identified various methods for producing such a pot, including extrusion and braiding. The soil-degradable rubber composition is characterized in that the rubber component comprises natural rubber or synthetic rubber with a polyisoprene structure.

Patent description PL236220B1 describes a biodegradable flowerpot made from comminuted biochar obtained through pyrolysis and/or biomass tarification, in an amount of 70-99% by weight, and a biodegradable binder in the form of a urea-formaldehyde resin solution and/or a protein binder in an amount of 1-30% by weight. According to the description, the binder solution may contain known fertilizer salts. The pots were formed using known methods, for example, in press molds, to the desired shape. The pot is characterized in that it contains natural fibers ranging from 1 to 50 mm in length, in an amount of 0.1 to 20% by weight. It has been noted that the addition of natural fibers, such as cellulose fibers, increases the mechanical strength of the pots. Patent description PL236101B1 describes a method for forming such a biodegradable flowerpot. It is made from an aqueous suspension of biochar particles and a nonwoven material with a water-soluble binder. A pot-shaped mold is introduced into the suspension, and a porous partition forces the suspension to flow until a layer of suspension particles 1 to 20 mm thick forms on the mold's surface. The mold is then dried and heated at an elevated temperature.

Japanese patent JP2001190157 describes a method for preparing a container/pot for growing seedlings, made from a mixture of carbonaceous material and a biodegradable resin, defined as an aliphatic or lactic acid-based polymer. The biodegradable container is produced by liquefying the resin and then mixing it with powdered carbonaceous material in a 4:1 weight ratio. The mixture is transferred to a mold, where it solidifies.

U.S. Patent No. 8,474,181 discloses a method of constructing a biodegradable flowerpot from layers of paper reinforced by heat gluing with a biodegradable polyethylene film. The biodegradable flowerpot as described herein comprises a paperboard substrate formed from natural cellulose fibers, an internal sealing composition incorporated into the paperboard substrate so as to render the paperboard substrate substantially resistant to saturation with liquid water, and a layer of a thermoplastic polymer on one of the major surfaces of the paperboard substrate.

Known methods for producing flowerpots do not address the production of flowerpots from biodegradable polymers that have a nonwoven structure. The method for producing a nonwoven flowerpot obtained according to the invention is distinguished by a simple and rapid production method, requiring no conversion from commonly used industrial machinery to specialized equipment. The nonwoven flowerpot obtained according to the invention does not require drying or lengthy shaping and is ready for use immediately after production. Additionally, the flowerpot structure exhibits good mechanical properties and high air permeability, which is essential for proper plant growth. Thanks to the porous and flexible structure of such flowerpots, plant roots can easily escape the flowerpot without inhibiting its growth. By adjusting the production parameters and using an appropriate polymer blend, flowerpots with varying surface area and thickness can be obtained, providing a realistic opportunity to create a flowerpot suitable for a given application. It's also important to note that the majority of plastics currently used to construct plant pots are not biodegradable, and introducing them into the soil leads to soil contamination. The proposed solution is ecological and innovative thanks to selected biopolymers and their blends.

A method for manufacturing nonwoven flowerpots for horticultural and agricultural applications, using a pneumatic method from biodegradable polymers using a single- or twin-screw extruder, which comprises drying the polymer granulate, introducing a component imparting a dark color in the form of a masterbatch or activated carbon, then introducing the dried polymer granulate to the extruder, in which it is melted and plasticized, and then blow-extruded from the extruder head in the form of fibers, which are discharged onto a constantly rotating pot-shaped receiver, located at a specific distance from the extruder head, characterized in that the material from which the nonwoven flowerpots are manufactured is polylactide or bio-based polybutylene succinate or a mixture of bio-based polybutylene succinate with a polymer such as polyhydroxyalkanoate (PHA) or a copolymer of butylene adipate and butylene terephthalate (PBAT) and a dye in the form of a masterbatch or activated carbon is added in the amount of 0.1%-10% in relation to the mass of the polymer or polymer mixture, wherein the polymer granulate dried at a temperature not exceeding 130°C, for up to 7 hours, preferably 80°C and 5 hours, is subjected to melting and plasticization in subsequent zones of the extruder with temperatures in the individual zones in the range of: 150°C-180°C, 160°C-200°C, 160°C-210°C, 170°C-210°C, 170°C-220°C, 180°C-230°C, 190°C-260°C, and is extruded at a speed in the range of 20-50 rpm, preferably 40 rpm, and then blown into fibers with air at a temperature of 200°C-260°C, flowing at a rate of 30-60 ^Nm3 /h, using 45 ^Nm3 /h from an extruder head at a temperature of 190°C-260°C, using 220°C and collected in a form of a pot, rotating at a constant speed of 2000 rpm at a distance of 20-40 cm, preferably 30 cm, from the extruder head, finally the pots are removed from the mold at equal time intervals of 15 to 45 seconds, preferably every 30 seconds.

The nonwoven flowerpot produced using a single-stage process according to the invention is characterized by a wall mass of 117-439 and a thickness of 0.205-0.975, depending on the selected polymer composition and technological parameters of the process. Physical properties, such as air permeability and ball puncture resistance, depend on the technological parameters and vary, particularly by the distance of the receiver from the forming head.

PL 249186 Β1

The method according to the invention is illustrated by the following examples.

Example 1

A nonwoven flowerpot was made from biobased polybutylene succinate (BioPBS) granulate with a 5% by weight addition of a brown polylactide-based masterbatch, which colored the product brown. The mixture was dried at 80°C for 5 hours. The granulate was fed to a Zamak Mercator EH-16D twin-screw extruder and processed using the parameters given in Table 1 below. The fiber web was removed from a metal mold 30 cm away, rotating at a constant speed of 2000 rpm, with the following dimensions: base diameter di = 48 mm, top diameter d2 = 60 mm, and height h = 65 mm. The pots were removed at regular intervals of 30 seconds.

Table 1

Extruder zone temperature (°C) Temperature (°C) Air flow rate (Nm²/h) Extruder speed (rpm) head air SI S2 S3 S4 S5 S6 S7 180 190 200 200 210 210 220 220 220 45 50

The pot obtained using the parameters given in Table 1 was characterized by the technological parameters given in Table 2 below.

Table 2

Fiber diameter (pm) 5.39 ± 3.982 Maximum compressive load (N) 16.763 ± 2.322 Compressive strain (5 N load) (%) 31,961 + 2,368 Air permeability (l/rn ² -s“ ^L ) External page Inside 274 176 Surface weight (g/m ² ) 261 Thickness d (mm) 0.475

Example 2

A nonwoven flowerpot was made from biobased polybutylene succinate (BioPBS) granulate with a 5% by weight addition of a brown polylactide-based masterbatch, which colored the product brown. The mixture was dried at 80°C for 5 hours. The granulate was fed to a Zamak Mercator EH-16D twin-screw extruder and processed using the parameters given in Table 3 below. The fiber web was removed 20 cm from the mold, rotating at a constant speed of 2000 rpm, into a metal mold with the following dimensions: base diameter di = 48 mm, top diameter d2 = 60 mm, and height h = 65 mm. The pots were removed at regular intervals of 45 seconds.

PL 249186 Β1

Table 3

Extruder zone temperature (°C) Temperature Air flow rate (Nm²/h) Extruder speed (rpm) CO2 head air CO SI S2 S3 S4 S5 56 S7 180 190 200 200 210 210 220 220 220 45 50

The pot obtained using the parameters given in Table 3 was characterized by the technological parameters given in Table 4 below.

Table 4

Fiber diameter (pm) 14.754 ± 7.071 Maximum compressive load (N) 25.817 ± 6.603 Compressive strain (5 N load) (%) 23,684 + 3,115 Air permeability (l/nY-s ¹ ) External page Inside 237 116 Surface weight (g/m ² ) 439 Thickness d (mm) 0.957

Example 3

A nonwoven flowerpot was made from polylactide (PLA) granules with a 5% by weight addition of a brown polylactide-based masterbatch, which colored the product brown. The mixture was dried at 80°C for 5 hours. The granulate was fed to a Zamak Mercator EH-16D twin-screw extruder and processed using the parameters given in Table 5 below. The fiber web was removed 30 cm away from a metal mold rotating at a constant speed of 2000 rpm. The mold dimensions were: base diameter di = 48 mm, top diameter d2 = 60 mm, and height h = 65 mm. The pots were removed at regular intervals of 30 seconds.

Table 5

Extruder zone temperature (°C) Temperature Air flow rate (Nm ³ /h) Extruder speed (rpm) CC head) air CC) SI S2 S3 S4 S5 56 S7 180 200 210 210 220 220 220 220 230 45 50

The pot obtained using the parameters given in Table 5 was characterized by the technological parameters given in Table 6 below.

PL 249186 Β1

Table 6

Fiber diameter (pm) 6.473 ± 2.071 Maximum compressive load (N) 8.077 ± 2.582 Compressive strain (5 N load) (%) 28.568 ± 1.225 Air permeability (!/m ² -s ^_1 ) External page Inside 351 248 Surface weight (g/m ² ) 142 Thickness d (mm) 0.812

Example 4

A nonwoven pot was made from a 75:25 blend of biobased polybutylene succinate (BioPBS) and polyhydroxyalkanoate (PHA) granules with 0.5% by weight of activated carbon. The blend was dried at 80°C for 5 hours. The granules were fed to a Zamak Mercator EH-16D twin-screw extruder and processed using the parameters given in Table 7 below. The fiber web was removed 30 cm from the mold, rotating at a constant speed of 2000 rpm, and measuring: base diameter di = 48 mm, top diameter d2 = 60 mm, and height h = 65 mm. The pots were removed at regular intervals of 30 seconds.

Table 7

Extruder zone temperature (°C) Temperature Air flow rate (Nm ³ /h) Extruder speed (rpm) head (T) air ('C) SI S2 S3 S4 S5 S6 S7 160 170 180 180 190 190 200 200 220 45 40

The pot obtained using the parameters given in Table 7 was characterized by the technological parameters given in Table 8 below.

Table 8

Fiber diameter (pm) 9.301 ± 6.800 Maximum compressive load (N) 23.405 ± 0.020 Compressive strain (5 N load) (%) 35.834 ±2.010

PL 249186 Β1

Air permeability (l/nF-s' ¹ ) External page Inside 753 665 Surface weight (g/m ² ) 170 Thickness d (mm) 0.453

Example 5

A nonwoven pot was made from a 50:50 blend of biobased polybutylene succinate (BioPBS) and polyhydroxyalkanoate (PHA) granules with 0.5% by weight of activated carbon. The mixture was dried at 80°C for 5 hours. The granules were fed to a Zamak Mercator EH-16D twin-screw extruder and processed using the parameters given in Table 9 below. The fiber web was removed 30 cm from a metal mold rotating at a constant speed of 2000 rpm. The mold dimensions were: base diameter di = 48 mm, top diameter d2 = 60 mm, and height h = 65 mm. The pots were removed at regular intervals of 30 seconds.

Table 9

Extruder zone temperature (°C) Temperature Air flow rate (Nm ³ /h) Extruder speed (rpm) head (°O air ('C) SI S2 S3 S4 S5 S6 S7 150 160 170 170 180 180 190 190 200 45 40

The pot obtained using the parameters given in Table 9 was characterized by the technological parameters given in Table 10 below.

Table 10

Fiber diameter (pm) 5.344 ± 3.902 Maximum compressive load (N) 8.359 ± 0.661 Compressive strain (5 N load) (%) 32.65412.136 Air permeability (l/m ² s“ ^J ) External page Inside 1162 1011 Surface weight (g/m ² ) 117 Thickness d (mm) 0.458

Example 6

The non-woven pot was made from a mixture of bio-based granules of polybutylene succinate (BioPBS) and poly(butylene adipate-butylene terephthalate copolymer) (PBAT) in a ratio of 75:25 with the addition of 0.5% by mass of activated carbon. The mixture was dried at a temperature

PL 249186 Β1

80°C for 5 hours. The granulate was fed to a Zamak Mercator EH-16D twin-screw extruder and processed using the parameters given in Table 11 below. The fiber web was removed to a metal mold rotating at a constant speed of 2000 rpm with the following dimensions: base diameter di = 48 mm, top diameter d2 = 60 mm, and height h = 65 mm. The pots were removed at regular intervals of 30 seconds.

Table 11

Extruder zone temperature (°C) Temperature Air flow rate (Nm ³ /h) Extruder speed (rpm) CC head) air CC) SI S2 S3 54 S5 S6 57 180 190 190 200 210 220 240 260 260 45 30

The membrane obtained using the parameters given in Table 11 was characterized by the technological parameters given in Table 12 below.

Table 12

Fiber diameter (pm) 7.269 ± 4.329 Maximum compressive load (N) 16.194 ± 3.578 Compressive strain (5 N load) (%) 36,256 +1,675 Air permeability (l/rrC-s ^-1 ) External page Inside 521 266 Surface weight (g/m ² ) 270 Thickness d (mm) 0.205

Example 7

A nonwoven pot was made from a 50:50 blend of biobased polybutylene succinate (BioPBS) and poly(butylene adipate-butylene terephthalate copolymer) (PBAT) granules with 0.5% by weight of activated carbon. The blend was dried at 80°C for 5 hours. The granules were fed to a Zamak Mercator EH-16D twin-screw extruder and processed using the parameters given in Table 13 below. The fiber web was removed 20 cm away from a metal mold rotating at a constant speed of 2000 rpm. The mold dimensions were: base diameter di = 48 mm, top diameter d2 = 60 mm, and height h = 65 mm. The pots were removed at regular intervals of 30 seconds.

Table 13

Extruder zone temperature (°C) Temperature Air flow rate (NrrP/h) Extruder speed (rpm) head what air (O SI S2 S3 S4 S5 S6 S7 180 190 190 200 210 220 240 250 260 45 40

PL 249186 Β1

The pot obtained using the parameters given in Table 13 was characterized by the technological parameters given in Table 14 below.

Table 14

Fiber diameter (pm) 32.015 ± 13.768 Maximum compressive load (N) 91,224 + 7,145 Compressive strain (5 N load) (%) 27.675 + 0.603 Air permeability (l/m ² -s' ^ł ) External page Inside 676 592 Surface weight (g/m ² ) 333 Thickness d (mm) 0.477

Example 8

A nonwoven pot was made from a blend of biobased polybutylene succinate (BioPBS) and poly(butylene terephthalate-butylene copolymer adipate) (P8AT) granules in a 25:75 ratio, with the addition of 0.5% activated carbon. The mixture was dried at 80°C for 5 hours. The granulate was fed to a Zamak Mercator EH-16D twin-screw extruder and processed using the parameters given in Table 15 below. The fiber web was removed 30 cm from a metal mold rotating at a constant speed of 2000 rpm. The mold dimensions were: base diameter di = 48 mm, top diameter d2 = 60 mm, and height h = 65 mm. The pots were removed at regular intervals of 30 seconds.

Table 15

Extruder zone temperature (°C) Temperature Air flow rate (Nm ³ /h) Extruder speed (rpm) head (°C) air (°C) SI S2 S3 S4 S5 S6 S7 180 190 190 200 210 220 230 240 260 45 40

The pot obtained using the parameters given in Table 15 was characterized by the technological parameters given in Table 16 below.

PL 249186 Β1

Table 16

Fiber diameter (μηη) 47,851 + 16,665 Maximum compressive load (N) 37.445 ± 5.625 Compressive strain (5 N load) (%) 43.493 ± 2.635 Air permeability (l/m ² ^ ¹ ) External page Inside 449 381 Surface weight (g/m ² ) 238 Thickness d (mm) 0.210

Claims (1)

1. A method for producing nonwoven flowerpots for horticultural and agricultural applications, using a pneumatic method from biodegradable polymers using a single- or twin-screw extruder, which comprises drying the polymer granulate, introducing a component imparting a dark color in the form of a masterbatch or activated carbon, then introducing the dried polymer granulate into the extruder, where it is melted and plasticized, and then blow-extruded from the extruder head in the form of fibers, which are discharged onto a constantly rotating pot-shaped receiver, located at a specific distance from the extruder head, characterized in that the material from which the nonwoven flowerpots are produced is polylactide or bio-based polybutylene succinate or a mixture of bio-based polybutylene succinate with a polymer such as polyhydroxyalkanoate (PHA) or adipate copolymer. butylene and butylene terephthalate (PBAT) and a dye in the form of a masterbatch or activated carbon is added in the amount of 0.1%—10% in relation to the mass of the polymer or polymer mixture, wherein the polymer granulate dried at a temperature not exceeding 130°C, for up to 7 hours, preferably 80°C and 5 hours, is subjected to melting and plasticization in subsequent zones of the extruder with temperatures in the individual zones in the range of: 150°C-180°C, 160°C-200°C, 160°C-210°C, 170°C-210°C, 170°C-220°C, 180°C-230°C, 190°C-260°C, and is extruded at a speed in the range of 20-50 rpm, preferably 40 rpm, and then blown in in the form of fibers with air at a temperature of 200°C-260°C, flowing at a rate of 30-60 ^Nm3 /h, using 45 ^Nm3 /h from the extrusion head at a temperature of 190°C-260°C, using 220°C and collected on a mold in the form of a pot, rotating at a constant speed of 2000 rpm at a distance of 20-40 cm, preferably 30 cm, from the extrusion head, finally the pots are removed from the mold at equal time intervals of 15 to 45 seconds, preferably every 30 seconds.