WO2021194440A1

WO2021194440A1 - The content of a biodegradable and compostable, breathable film and the production process of this film

Info

Publication number: WO2021194440A1
Application number: PCT/TR2020/050395
Authority: WO
Inventors: Ali Zafer SISMAN; Almila Cerci Izmit
Original assignee: Pelsan Tekstil Urunleri San. Ve Tic. A.S.
Priority date: 2020-03-24
Filing date: 2020-05-07
Publication date: 2021-09-30
Also published as: EP4127030A4; EP4127030A1

Abstract

The invention relates to the content of a biodegradable and compostable, breathable film for use in many areas, particularly in the hygiene and medical sectors, and the production process of this film. The most important feature of the biodegradable and compostable, breathable film of the present invention is that it is breathable and contains a ternary polymer blend. Biodegradable and compostable, breathable film of the present invention is obtained as a result of a process involving compound extrusion (100), film extrusion (110) and stretching (120) Steps.

Description

THE CONTENT OF A BIODEGRADABLE AND COMPOSTABLE, BREATHABLE FILM AND

THE PRODUCTION PROCESS OF THIS FILM

Field of Invention and Technical Field

The invention relates to a biodegradable and compostable, breathable film content for use in many areas, particularly in the hygiene and medical sector, and the production process of this film. The most important feature of the biodegradable and compostable, breathable film the present invention is to be breathable and to have ternary polymer blend. The biodegradable and compostable, breathable film of the present invention is obtained as a result of a process involving compound extrusion, film extrusion and stretching steps.

State of the Art

With the developing technology today, the consumption of societies has increased, and the consumption habits have led to various problems together. The problems created by the consumption habits are the common problem of the whole world. The sustainability is a concept that can minimize these problems even if they cannot solve completely. The sustainability aims to transfer natural resources to the next generations, and while aiming at this, it does not ignore the needs of people.

Plastics is the third most widely used petroleum-based in the world. More than 200 million tons of plastic are consumed every year, and these plastics are of petroleum origin such as polystyrene, polypropylene, polyethylene, polymethylmethacrylate and polyvinylchloride. It decomposes in nature for over 500 years and this affects the living creatures negatively. In addition, such plastics cause death of marine animals and poultry by being swallowed by them. On the other hand, big piles of rubbish created by these wastes are also environmentally problematic. In the light of this information, biodegradable solutions and bioplastics are subjects open to improvement. Instead of synthetic and non-biodegradable plastics, which cause environmental pollution due to increased dependency on petroleum, there is a great need for plastic materials based on biological raw materials obtained from sources, which are degrading in nature and can be produced repeatedly from nature.

1

SUBSTITUTE SHEETS (RULE 26) The use of bioplastics as an alternative to petroleum-based plastics is encouraged. Bioplastics are made of natural polymers such as agricultural wastes, cellulose, potatoes and corn starch. It is 100% degradable in nature, and is equally durable and versatile as petroleum-based plastics. It is used in many sectors such as agriculture, textile, medicine and packaging. The popularity of bioplastics has been increasing in European and American countries for ecological reasons. Reducing carbon footprint, saving energy in production, being renewable and reducing non- biodegradable waste that pollutes the environment are the advantages of bioplastics. It also contains no harmful chemicals such as phthalates and bisphenols A and when used as packaging, it does not change the taste or smell of the food.

It must be known that not all bioplastics are degradable in nature. The bioplastics obtained only from renewable biological resources are biodegradable.

Biodegradable polymers are polymers that can be degraded and composted by the effects of bacteria, fungi, algae, yeast and other microorganisms found in nature. Biodegradable polymers can be produced naturally by living organism, or they can also be synthetically produced but their biodegradability is proven. Cellulose, starch, leather, chitin, chitosan, bacterial polyester are examples of polymers produced by the living organism. Polylactic acid (PLA), polycaprolactone (PCL), polyglycolic acid (PGA) and poly (butylene adipate-co-terephthalate) (PBAT) are synthetically produced but biodegradable polymers.

Besides plastic wastes causing environmental problems, the share of hygiene products and especially baby diapers in these wastes is large. The third most common waste is baby diapers and it also accounts for %30 of the non-biodegredable wastes. According to a report from the United States Environmental Protection Agency, disposable baby diapers or disposable adult diapers create 3.5 million tons of waste every year across the country. Apart from plastic wastes, this type of product also harms the environment because it contains pathogenic solid wastes. The researches show that the decomposition of product in nature takes up to 500 years and that, meanwhile, toxic gases such as methane etc. are released. In addition, it is estimated that 200000 trees annually disappear in the USA to make disposable diapers.

In the state of art, as an alternative to disposable diapers, there are diapers that can be washed and reused and biodegradable diapers.

"Biodegradable, biobased diaper" patent No US2017224540 relates to a biobased and/or biodegradable disposable diaper configuration. In this study, the parts of the diaper are defined

2

SUBSTITUTE SHEETS (RULE 26) as outer layer, inner layer, absorbent pad, side layer, fasteners, and elastic waistband. It is stated that the diaper of the present invention, consists of more than 25% biobased content. As content, it contains components such as aromatic polyester (PBS, polybutylene succinate, PBT, polybutylene terephthalate, PBAT, poly (butylene adipate terephthalate) or combinations of these), biodegradable polymer containing cellulosic polymer, polylactic acid (PLA), bamboo or cotton, modified starch, cellulose, keratin. In this patent, there is no study for the compatibility of PBAT, PLA, and TPS trio. At the same time, the diaper does not have a breathable feature and is partly biodegradable.

“Biodegradable breathable film and laminate” patent No US2002098341 relates to a film content for use in personal care products and medical disposable products. The invention is described as a breathable, stretch-thinned film, and is expressed to include filler particles and biodegradable thermoplastic polymer. The film has gaps around the filler particles to facilitate the passage of water vapor. Biodegradable thermoplastic polymer can be selected from polylactic acid, polycaprolactone and polyesters of butendiol, adipic acid, succinic acid and / orterephthalic acid. It may also be possible to use the film as a laminate consisting of more than one layer.

"Highly breathable biodegradable films" patent No US2010/0068484 relates to a highly breathable and biodegradable film. The invention consists of a biodegradable polymer matrix and first and second filler particles dispersed in this matrix. It is stated that the first filler material is calcium carbonate, the second filler material is titanium dioxide, and the biodegradable polymer may be aromatic polyester, aliphatic polyester, aromatic-aliphatic copolyester or combinations of these. This study also focuses on the production of the film.

In the article “Characterization of TPS / PLA Blends Obtained by Extrusion and Thermopressing (Carmen M. O. Muller, Alfredo T. N. Pires and Fabio Yamashita)”, there are test results on the mechanical properties and water vapor permeability of PLA / TPS mixtures prepared by extrusion and thermo press and water absorption isotherms. Morphological properties of the samples are displayed in SEM and thermal properties of pure polymers and mixtures are determined by DSC. In this study, SEM (scanning electron microscope) and DSC (differential scanning calorimetry) results show that TPS / PLA mixtures do not intermingle and the presence of two phases.

"Biodegradable and breathable polymer film" patent No W02005/056656 relates to a biodegradable, breathable film composition. The film contains 30-70% by weight of biodegradable copolyester and 30-70% of filler. When treated to stretching operation as monoaxial or biaxial, the gaps increase and water vapor permeability is at least 800 gr/ m2 / 24 hours. It is stated that

3

SUBSTITUTE SHEETS (RULE 26) the copolyester can be selected from aliphatic or aromatic acids, and the filler material can preferably be calcium carbonate. The film is applicable to disposable breathable products such as personal care products, absorbent products, health products, medical fabrics.

"Biodegradable films having enhanced ductility and breathability" patent No W002/085421 relates to personal care products containing biodegradable film. The biodegradable film of the present invention has breathability and high ductility. It consists of a biodegradable polymer and a water- soluble polymer (preferably polyethylene oxide polyethylene glycol or a copolymer).

In the state of the art, many studies have been found on biodegradable films that can be used in the hygiene and medical industry. In some of these studies, the breathability has also been shown to be prominent. The breathability is an important feature in diapers. Although microporous breathable products do not leak fluid, water vapor is removed from the skin by means of selective permeable layers. This type of breathable diapers retain normal skin moisture and eliminate friction with less pore blocking. It also prevents fungus formation and provides additional benefits in rash prevention.

Another noticeable situation in the state of the art is that biodegradable films generally contain single or double polymer structure. There are no studies involving ternary polymer blend. At the same time, it was not possible to create a polymer composition with PBAT, PLA and TPS polymers, these three incompatible polymers, whose molecular structures are given below, could not be harmonized for high efficiency. In this sense, a film which can be used in many fields, especially in the hygiene and medical sector, is more environmentally friendly than the state of the art, is biodegradable and compostable in a shorter time, has ternary polymer blend and also superior properties, and is breathable is required.

4

SUBSTITUTE SHEETS (RULE 26)

Technical Problems which the Invention Aims to Solve

With the biodegradable and compostable, breathable film of the present invention, a film which has superior features compared to the state of the art, contains ternary polymer blend, and can be used in many fields especially in the hygiene and medical sector.

The most important feature of the biodegradable and compostable, breathable film of the present invention is that it is environmentally friendly with its biodegradable structure. Thanks to this feature, it will significantly reduce plastic waste from disposable diapers, especially diapers, etc. With the reduction of plastic wastes, the problems of not dissolving and degrading in nature, which are in the state of the art, will be prevented for many years.

One advantage of the biodegradable and compostable, breathable film of the present invention, is that it is breathable. It is expected that the film will be microporous and breathable in terms of skin health, especially in products such as diapers, underpads and adult diapers. Another advantage of the biodegradable and fertilizable, breathable film of the present invention is that it contains polylactic acid (PLA). Polylactic acid is a thermoplastic aliphatic polyester and has a molecular structure as follows. It has a melting temperature above 150 C°. Having a high melting temperature provides ease of processing in the process without degradation of the melt. It also has a polylactic acid, stiff, tough structure. It is both biobased and a biodegradable and compostable polymer.

5

SUBSTITUTE SHEETS (RULE 26) Another advantage of the biodegradable and compostable, breathable film of the present invention is that it contains poly (butylene adipate-co-terephthalate) (PBAT). Unlike PLA, PBAT is a low melting temperature (120 C°) polymer. For this reason, it is difficult to process alone. However, with its flexible and elastic structure, it is a polymer that improves the mechanical properties of the film and provides convenience in the stretching phase of the process. The molecular structure of PBAT is as follows and is a synthetic polymer. It is biodegradable and compostable.

Another advantage of the biodegradable and compostable, breathable film of the present invention is that it contains thermoplastic starch (TPS). TPS is a very difficult polymer to process because it retains a lot of moisture in it. However, excessive moisture speeds up the degradation of the biodegradable product. In other words, moisture (water) is a catalyst that accelerates dissolution in nature. The molecular structure is as follows and it is a biobased and biodegradable polymer.

Another advantage of the biodegradable and compostable, breathable film of the present invention is that it contains calcite (CaC03). Calcite, provides micropores in the ternary polymer matrix with the contribution of stretching method, so it gives a breathable feature to the film.

Another advantage of the biodegradable and compostable, breathable film of the present invention is obtained by harmonizing TPS, PI_A and PBAT polymers that are incompatible with each other by creating a ternary polymer blend, the film obtained in this way is more harmless than the state of the art. This means that it can biodegrade and compost in a shorter time in nature and constitutes a different advantage of the invention.

6

SUBSTITUTE SHEETS (RULE 26) The following figures will be used to better understand the biodegradable and compostable, breathable film of the present invention, and its production process.

Description of Figures Figure-1 is a flow chart showing the process steps of the production process of the biodegradable and compostable, breathable film of the present invention.

Figure-2 is a representative view of the device where the compound extrusion takes place in the production process of the biodegradable and compostable, breathable film of the present invention. Figure-3 is a representative view of the blown device where the film is extruded in the production process of the biodegradable and compostable, breathable film of the present invention.

Figure-4 is a representative view of the device where the stretching process takes place in the production process of the biodegradable and compostable, breathable film of the present invention. Figure-5 is a representative view of the calcite particles on the biodegradable and compostable, breathable film before stretching.

Figure-6 is a representative image of calcite particles and microporosities on biodegradable and compostable breathable film after stretching.

Reference Numbers of Part, Section and Flow to Help Explaining the Invention

1- Compound extrusion line 1a- First feeder

1 b- Second feeder 1c- Feeding entry

7

SUBSTITUTE SHEETS (RULE 26) 1d- Barrel 1e- Vacuum

1f- Cutting/Pelletizing unit

2- Blown film extrusion line 2a- Feeder

2b- Extruder 2c- Die head 2d- Cooling chamber 2e- Nip rolls 2f- Other rolls

2g- Film rolls

3- Stretching Unit 3a- Stretching rolls 3b- Calcite 3c- Pores

Process Flow Chart to Help Explaining the Invention

100- Compound Extrusion Step 110- Film Extrusion Step 120- Stretching Step

Detailed Description of the Invention

Biodegradable, compostable and breathable film of the present invention is a film that will be an alternative to plastics in the state of the art, degrade in nature in a short time, will be environmentally friendly and can be used in various fields. It has also a breathable feature with its microporous structure.

8

SUBSTITUTE SHEETS (RULE 26) The biodegradable and compostable, breathable, film of the present invention is most commonly composed of the ternary structure of thermoplastic starch (TPS), poly(butylene adipate-co- terephthalate) (PBAT) and polylactic acid (PLA). It should be noted that these three materials are polymers difficult to be harmonized.

The components and weight percentages of the film of the present invention are as follows:

Table 1: Components of the Invention Subject and Percentage by Weight

As given in Table 1 , the biodegradable and compostable, breathable film which is the present invention contains PLA in the range of 10-50%, PBAT in the range of 10-70%, TPS in the range of 1-30%, calcite in the range of 10-50% and compatibilizer in the range of 0.1-10% by weight. It is preferred that calcite has technically particle size in the range of 0.5-3.0 pm d50, and its moisture value is less than 0.20%. Calcite is used as filler material and also gives the film breathable feature.

In the biodegradable and compostable, breathable film, which is the subject of the invention, there is a compatibilizer between 0.1-10% by weight. Preferably, maleic anhydride graft polymer is used as compatibilizer, which acts as a binder with three incompatible polymers, PLA-PBAT-TPS.

The percentage of PLA by weight is in the range of 10-50%. Technical characteristics of the PLA to be used preferably have a moisture value in the range of 0.15-0.25%, melt flow index in the range of 3-15 g / 10 min., and its density should be between 1,15-1 ,35 g / cm³. PBAT is biodegradable polyester. It is in the range of 10-70% by weight in the content of the biodegradable and compostable, breathable film of the present invention. Technically it is preferred that it has a humidity value in the range of 0.15-0.25%, and the melt flow index of 2-6 g / 10 min. and the density is between 1.15-1.35 g/cm³.

9

SUBSTITUTE SHEETS (RULE 26) The content of the thermoplastic starch in the film is preferably in the range of 0-30% by weight. The melt flow index should preferably be 1-10 g / min. and the density should be between 1.30- 1.50 g/cm³.

The technical properties of the biodegradable and compostable, breathable film obtained with the above contents are expected to be as follows:

Table 2: Technical Properties of the Film of the Present Invention

According to the data in Table 2, the basis weight of the biodegradable and compostable, breathable film of the present invention varies in the range of 10-30 g / m². The basis weight refers to the mass in the unit area, and low basis weight is more advantageous in terms of degredation time in nature. It also affects breathability. It can be said that the permeability of low basis weight films is higher. In terms of breathability, the film of the invention is expected to have a water vapor permeability in the range of 500-10000 (g / (m²-day)). High permeability is aimed here. The maximum tensile strength in the machine direction (longitudinal) is expected to be in the range of 15-30 N, and the maximum tensile strength in the opposite direction (transverse) of the machine is in the range of 2.5-15 N. While the elongation at break in the machine direction (longitudinal) is in the range of 5-200%, the elongation at break in the opposite direction (transverse) of the machine is in the range of 30-400%.

The production process of the biodegradable and compostable, breathable film of the present invention is generally obtained from the raw materials by the extrusion process to obtain the semi finished compound, and the semi-finished product to be subjected to the re-extrusion process and the film to be finalized by stretching. The film extrusion process can be in the form of blown or cast extrusion.

10

SUBSTITUTE SHEETS (RULE 26) A flow chart of these process steps is given in Figure 1 and the process steps will be examined in detail in the following titles.

Compound Extrusion Step (100) Film Extrusion Step (110) Stretching Step (120)

Compound Extrusion Step (100)

Compound is a concept known by the industry and is a new raw material created with the desired feature by enriching polymers with various organic and/or inorganic additives. The first Step of the production process of the biodegradable and compostable, breathable film of the present invention will be compound extrusion. This Step takes place via a representative device schematized in Figure 2. Accordingly, PLA, PBAT, TPS polymers and compatibilizers are fed together, and calcite is fed to the system separately. According to the scheme in Figure 2, polymers and compatibilizer are fed to the system through the first feeder hopper (1a) and calcite from the second feeder hopper (1b). The materials reaching the barrels (1d) from the feeding entries (1c) are extruded by heating, melting and mixing in the twin-screw system. Then, this step ends by coming to the cutting unit (1f) and granulating by cutting. Round granules are preferred because the underwater cutting system and flat granules will absorb moisture. At this Step, cutting water and barrel temperatures are important parameters. The cutting water should preferably be in the range of 40-80 ° C. Barrel temperature values can also be called extruder temperature and it is preferred to be between 120-180 ° C. With the help of vacuum (1e), moisture and oligomers are expelled.

Film Extrusion Step (110)

At this step, compound granules are subjected to a second extrusion process to form a film. In Figure 3, a representative device for film extrusion is schematized. According to this scheme, the granules fed to the system from the feeder (2a) are melted in the extruder (2b), preferably at a temperature between 150-200 ° C and sent to the die head (2c). Die head temperature will preferably be between 150-200 ° C. The melt passing through the die head (2c) is cooled by air in the cooling chamber (2d). The product, which becomes a film after cooling, comes out of the nip rolls (2e). The resulting film is wrapped by other rolls (2f) and becomes a film roll (2g) and the film extrusion step is completed.

Stretching Step (120)

11

SUBSTITUTE SHEETS (RULE 26) The final Step of the production process of the biodegradable and compostable of the present invention is stretching. In Figure-4, there is a schematic view of the film and the calcite particles on it before stretching. This film is stretched with the help of Stretching rolls (3a) on a representative device, the image of which is given in Figure-3, and a film as in Figure-5 is obtained. Accordingly, pores (3c) are formed around the calcite (3b), which is placed in the polymer matrix, and the film gains breathability with these micropores. The stretching is preferably in the machine direction in the proportions of 2: 1-4: 1. The stretching temperature is preferably in the range of 50-90 ° C.

The production process of the biodegradable and compostable, breathable film of the present invention is achieved by the above process steps. It should be remembered that the schemes of the production process of the biodegradable and compostable, breathable film of the present invention are representative, and the tools and equipment here are not binding. The process can be carried out with different equipment to perform the same duty.

In the compound extrusion step (100), polymers and compatibilizers can be fed together or separately fed. However, in each case, calcite should be fed separately. Although the cutting is preferably specified as an underwater pelletizing system, there may also be different alternative systems such as strand pelletizing or dry conveyor cutting system. Although the number of barrels is 13 in the diagram, this is not binding.

Although it is described on the basis of blown extrusion at the film extrusion step (110), it is also possible to produce the film by cast film extrusion. The film can be single layer or multilayer.

The film extrusion (110) and stretching (120) steps can be carried out as a continuous process or can be processed as batch. In any case, compound extrusion (100) will continue as a separate process.

How the Invention is applied to the Industry

The biodegradable and compostable, breathable film of the present invention can be used in many fields, especially in the hygiene and medical sectors baby diapers, disposable (adult) underpads, women's hygienic (femcare) products, medical pads, sanitary pads, bladder pads, breast pads, personal safety products and protective clothing are some of the applications.

12

SUBSTITUTE SHEETS (RULE 26)

Claims

1. The invention is the content of the biodegradable and compostable, breathable film is characterized in that the biodegradable and compostable, breathable film contains at least ternary polymer blend as polylactic acid, poly (butylene adipate-co-terephthalate) and thermoplastic starch, and mentioned film is biodegradable, compostable and breathable in nature.

2. A biodegradable and compostable breathable film according to Claim 1, is characterized in that the content of the film contains polylactic acid in the range of 10-50% by weight.

3. A biodegradable and compostable breathable film according to Claim 1, is characterized in that the content of the film contains poly(butylene adipate-co-terephthalate) in the range of 10-70% by weight.

4. A biodegradable and compostable breathable film according to Claim 1 is characterized in that the content of the film contains thermoplastic starch in the range of 1-30% by weight.

5. A biodegradable and compostable breathable film according to Claim 1 is characterized in that the content of the film contains calcite in the range of 10-50% by weight.

6. A biodegradable and compostable breathable film according to Claim 1 is characterized in that the content of the film contains a compatibilizer, preferably maleic anhydride graft polymer, in the range of 0.1-10% by weight.

7. A biodegradable and compostable breathable film according to Claim 1, is characterized in that it is breathable and its water vapor permeability (WVTR) value is in the range of 500-10000 (g / (m²-day)).

8. A biodegradable and compostable breathable film according to Claim 1, is characterized in that its basis weight is in the range of 10-30 (g/m²).

9. The content of the biodegradable and compostable, breathable film according to Claim 1 , is characterized in that poly(butylene adipate-co-terephthalate) used in breathable film has a moisture value in the range of 0.15-0.25%, the melt flow index is 2-6 g / 10 min, and its density is in the range of 1.15-1.35 g / cm³.

10. The content of the biodegradable and compostable, breathable film according to Claim 1 is characterized in that polylactic acid used in biodegradable and compostable, breathable film having a moisture value in the range of 0.15-0.25%, the melt flow index is 3-15 g / 10 min, and its density is in the range of 1.15-1.35 g / cm³.

11. The content of the biodegradable and compostable, breathable film according to Claim 1 , is characterized in that calcite used in biodegradable and compostable, breathable film has a d50 particle size in the range of 0.50-3.0 pm and its moisture value is less than 0.20%.

12. The content of the biodegradable and compostable, breathable film according to Claim 1 , is characterized in that the melt flow index of thermoplastic starch used in biodegradable and compostable, breathable film is 1-10 g / 10 min. range and density is 1.30-1.50 g / cm³.

13. The content of the biodegradable and compostable, breathable film according to Claim 1 is characterized in that biodegradable and compostable, breathable film can be used in the hygiene and medical sectors.

14. The content of the biodegradable and compostable, breathable film according to Claim 1 is characterized in that biodegradable and compostable, breathable film can be used in baby diapers, disposable (adult) underpads, women's hygienic (femcare) products, medical pads, sanitary pads, bladder pads, breast pads, personal safety products and protective clothing.

15. The invention is the production process of the biodegradable and compostable, breathable film, is characterized in that production process includes the following process steps:

Compound Extrusion Step (100)

Film Extrusion Step (110)

Stretching Step (120)

16. Production process of biodegradable and compostable, breathable film according to Claim 15 is characterized in that compound extrusion Step (100) of the production process, feeding the PLA, PBAT, TPS and maleic anhydride graft polymer into the system together or separately, feeding the calcite separately to the system, extruding the materials fed to the system by melting in the twin screw system in the barrels (1d). It includes the processes of obtaining round granules in the cutting unit (1f), preferably by underwater cutting.

17. Production process of biodegradable and compostable, breathable film according to Claim 15 and Claim 16 is characterized in that in the compound extrusion Step (100) of the production process, the cutting water temperature is preferably in the range of 40-80 ° C, and the barrel temperature values are preferably between 120-180 ° C.

18. Production process of biodegradable and compostable, breathable film according to Claim 15 is characterized in that the film extrusion step (110) of the production process is subjected to a second extrusion process of the compound granules to form a film. In accordance with this purpose, that second extrusion process includes some transactions as feeding the granules from the feeder (2a), the granules in the extruder (2b) preferably at a temperature of 150-200 ° C, and into the die head at a temperature of 150-200 ° C (2c) and subsequent cooling and filming processes in the cooling chamber (2d).

19. Production process of biodegradable and compostable, breathable film according to Claim 15 and Claim 18 is characterized in that the film extrusion step (110) of the production process can be realized as blown extrusion or cast extrusion.

20. Production process of biodegradable and compostable, breathable film according to Claim 15 is characterized in that the stretching process (120) of the production process preferably takes place in the machine direction, the stretching ratio is in the range of 2:1 - 4:1 and the stretching temperature is preferably in the range of 50-90 ^° C.