HK1176370A - Biodegradable film and laminate - Google Patents

Description

Biodegradable film and laminated material

Technical Field

The present invention relates to fabrics and laminates of biodegradable films and knitted, woven or non-woven fabrics, wherein the knitted, woven or non-woven fabrics are preferably, but not limited to, biodegradable.

Background

Polylactic acid (PLA) has become a leading biodegradable/compostable polymer in the past 20 years and has been used in the manufacture of plastics and fibers. Because polylactic acid, although derived from natural renewable materials, has thermoplastic properties and can be melt extruded to produce plastic articles, fibers or fabrics having good mechanical strength and flexibility comparable to petroleum-based compositions, such as polyolefins (polyethylene and polypropylene) and polyesters (polyethylene terephthalate and polyethylene terephthalate). Polylactic acid is made from lactic acid, which is a by-product from fermentation of corn (e.g., Zea mays), wheat (e.g., Triticumpp), rice (e.g., Oryza sativa), or sugar beet (e.g., Beta vulgaris). Lactic acid, when polymerized, forms a dimer repeat unit having the structure:

unlike other synthetic fibrous materials of vegetable origin (e.g., cellulose), PLA is more amenable to melt spinning into fibers. Compared with the solvent spinning process necessary for synthesizing cellulose fiber, the preparation of PLA fiber by adopting melt spinning can reduce economic cost and environmental cost, and the prepared PLA has wider performance. Like polyethylene terephthalate (PET), PLA polymers need to be dried before melting to avoid hydrolysis during melt extrusion, and both can achieve better tensile strength by drawing (drawing) fibers from the polymer. PLA molecules tend to assume a helical structure, which makes them easier to crystallize. Meanwhile, the lactic acid dimer has three isomers: a left-handed type, in which polarized light rotates clockwise; a right-handed type in which polarized light is rotated in a counterclockwise direction; and racemic forms, which are optically inactive. The relative proportions of these types can be controlled during the polymerization process, thereby controlling their important polymer properties relatively broadly. Control over thermoplastic "natural" fiber polymers, unique Polymer morphology, and isomer content in the Polymer allows manufacturers to design relatively broad Properties in the fiber (Dugan, J.S.2001, "Novel Properties of PLA Fibers," International Nonwovens Journal, 10 (3): 29-33; Khan, A.Y.A., L.C.Wadsworth, and C.M.Ryan, 1995, "Polymer-oid Nonwoves from Poly (lactic) Resin," International Nonwovens Journal, 7: 69-73).

PLA is considered not to be directly spontaneously decomposable in the extruded state. Instead, it must first be hydrolyzed before becoming biodegradable. In order to allow a greater degree of hydrolysis of PLA, it is necessary to simultaneously maintain a relative humidity equal to or higher than 98% and a temperature equal to or higher than 60 ℃. Once these conditions are met, degradation occurs rapidly (Dugan, J.S.2001, "Novel Properties of PLA Fibers," International Nonwoves Journal, 10 (3): 29-33 and Lunt, J.2000, "Polylactic acid polymers for Fibers and Nonwoves," International Fiber Journal, 15: 48-52). However, the composition and arrangement of the three isomers can be controlled by controlling the melting temperature between 120 ℃ and 175 ℃, whereas if the melting temperature is lower, the polymer will be completely amorphous. Adding enzymes and microorganisms to the melt will result in more amorphous polymer.

Polylactic acid has been used to make many different products, and factors controlling its stability and degradation rate have also been well documented. Both L-lactic acid and D-lactic acid produced during fermentation can be used to produce PLA (Hartmann, M.H., 1998, "High Molecular Weight Polymer acid polymers", p.367-411, In: D.L.Kaplan (ed.), biopolymer from Renewwave resources, Springer-Verlag, New York). One advantage of PLA is that its degradation rate can be controlled by varying factors such as the ratio of dextrorotatory and levorotatory forms, molecular weight, or crystallinity (Drumright, r.e., p.r., Gruber, and d.e.henton, 2000, "Polylactic acid technology," Advanced materials.12: 1841-1846). For example, Hartmann discovered in 1998 that unstructured polylactic acid samples rapidly degraded to lactic acid within weeks, but high crystallinity materials can take months to years to completely degrade. This flexibility and control makes PLA a very useful raw material for the production of agricultural mulch artifacts, which degrade in the ground after a certain amount of time has elapsed (Drumright, R.E., P.R., Gruber, and D.E.Henton, 2000, "Polylactic acid technology," Advanced materials.12: 1841-.

Polylactic acid is decomposed into small molecules by different mechanisms, and the final decomposition product is CO₂And H₂And O. The degradation process is influenced by temperature, humidity, pH and enzymes, as well as microbial activity, etc., but not by uv light (Drumright, r.e., p.r).Gruber, and d.e.henton, 2000, "polylactic acid Technology," Advanced materials.12: 1841-1846; lunt, 2000). In some early work on the evaluation of PLA degradation for biomedical applications, Williams discovered in 1981 that bromelain, pronase and proteinase K can accelerate the rate of PLA degradation (Williams, D.F., 1981, "enzymatic Hydrolysis of Polylactic Acid," Engineering in medicine.10: 5-7). Recently, Hakkarainen et al, in 2000, incubated 1.8 mm thick PLA samples in Mixed cultures of Microorganisms extracted from humus at 86 ℃ F. (Hakkarainen, M., S.Karlsson, and A.C.Albertsson, 2000., "Rapid (Bio) digestion of polylactic by Mixed Culture of composite Microorganisms-Low Molecular Weight Products and matrix polyurethanes", Polymer.41: 2331-. After 5 weeks incubation, the humus-treated films degraded to a fine powder, while the untreated control remained intact. It is noted that the present study only used the levorotatory form, and the degradation rate will vary with the ratio of the levorotatory to dextrorotatory forms. In any event, work in 2000 by Hakkarainen et al showed that decomposition could be accelerated by the use of a large array of microorganisms readily available from humic substances. Current PLA degradation studies are performed in liquid cultures in vitro, but also in active humus manipulation above 140 ° F (Drumright et al, 2000; Hakkarainen et al, 2000; Lunt, 2000; Williams, 1981). PLA degrades rapidly when made into humus at 140 ° F, reaching almost 100% biodegradation within 40 days (Drumright et al, 2000), but its stability is still being determined below 140 ° F when the fabric comes into contact with soil organics. Larry Wadsworth (Khan et al, 1995) at the University of Tennessee (University of Tennessee, USA) of America began to study first spunbonded fabrics (SB) and Meltblown (MB) Nonwovens (Smith, B.R., L.C.Wadsworth, M.G.Kamath, A.Wszelaki, and C.E.Sams, "Development of New Generation Biodegradable Mulch nonwoven Polyethylene plastics," International Conference on Sustainable Textiles (ICST 08), Wuxi, China, October 21-24，2008[Proceedings and CD ROM])。

Biodegradable polymers are required to be able to withstand many environmental factors during use, but are biodegradable when discarded. Biodegradation of PLA has been studied under various elevated temperatures, both aerobic and anaerobic, aqueous and solid conditions, and it has been found that exposure to an aerobic aqueous environment results in PLA that biodegrades very slowly at room temperature but rapidly at elevated temperatures. This finding is also supported by the fact that PLA must be hydrolysed before the microorganisms can use it as a nutrient source. At the same elevated temperature, PLA biodegrades much faster under anaerobic solid state conditions than under aerobic conditions. During natural humus, PLA behaves like degradation upon exposure to water, with biodegradation only starting after it is heated. These results reinforce a widely held view: PLA is compostable and stable at normal temperatures, but degrades rapidly during waste treatment in composting or anaerobic treatment facilities (Itavaara, Merja, Sari karjoma and Johan-Fredrik Selin, "Biodegradation of polylactic acid under high temperature conditions, both Aerobic and anaerobic (" biodegration of polylactic in Aerobic and anaerobic thermophilicity conditions ")" eischen verwen scientific press (Elsevier Science Ltd., 2002). In another study, the level of biodegradation of anaerobically digested sludge on various plastics was determined and compared to simulated landfill conditions. Bacterial poly-93-hydroxyvalerate (PHB/PHV), a natural aliphatic polyester produced by bacteria, degrades completely in almost 20 days in anaerobically digested sludge; however, aliphatic polyester PLA, synthesized from natural materials, and two other aliphatic polyesters evaluated: polybutylene succinate (poly) and polybutylene succinate-polyethylene succinate copolymer (poly) do not undergo any degradation after 100 days. A cellulose control material, cellophane, degraded similarly to PHB/HV over 20 days. Furthermore, PHB/HV degrades well under Simulated Landfill Conditions for 6 months (Shin, pyrong Kyun, Myung Hee Kim and Jong Min Kim, Biodegradability of Degradable Plastics Exposed to anaerobically Digested Sludge and Simulated Landfill Conditions ("biodegradation of Degradable Plastics expanded to anaerobic Digested Sludge and coated tensile Polymers"), Journal of polymer and Environment (Journal of Polymers and the Environment), vol.5, pp.1, 1566-.

In the search for truly biodegradable polymers, Polyhydroxyalkanoates (PHAs) have been naturally synthesized by many bacteria as intracellular carbon and energy storage substances. As early as the 20 th 19 th century, poly-R-3-hydroxyfatty acid esters (poly [ (R) -3-hydroxybutyrate, P (3HB)) have been isolated from Bacillus megaterium and subsequently identified as a stock polyester of bacteria. However, P (3HB) has not shown significant commercial value because it has been found to become brittle and hard over a long period of time and therefore cannot be used to replace the mainstream synthetic polymers Polyethylene (PE) and Polystyrene (PS). Finally, other hydroxy fatty acid ester (HA) units than 3HB have been found in microbial polyesters, which when included in P (3HB) can improve mechanical and thermal properties, which HAs a significant impact on the research and commercial interest of bacterial polyesters. Biodegradability in the natural environment is one of the unique properties of PHA materials. The microbial polyester is biodegradable in soil, sludge or seawater. Because PHA is a solid polymer with a high molecular weight, it is not well transported across cell walls as a nutrient. Thus, microorganisms like fungi and bacteria secrete extracellular enzymes that degrade PHA, called PHA degrading enzymes, which hydrolyze solid PHA to water-soluble oligomers and monomers, which can be transported into cells and subsequently metabolized as a source of carbon and energy (Numata, Keiji, Hideki Abe and Tadahisa Iwata, Biodegradability of polyhydroxyalkanoate Materials ("Biodegradability of polyhydroxylkonate Materials")) material (Materials), 2009, p 2 1104-. A random copolyester of [ R ] -3-hydroxybutyrate and [ R ] -3-hydroxyvalerate, P (3HB-co-3HV), is commercially produced by the Imperial chemical industries, England (ICI). Studies have shown that Alcaligenes eutrophus uses propionic acid and glucose as carbon sources to produce an optically active copolyester of3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV) (Holmes, PA, (1985), PHB application, Phys technology 16: 32-36, a Biodegradable thermoplastic Produced by bacteria ("Applications of PHB: a microbial Produced Biodegradable thermoplastic,"), Biodegradable copolyester from Kunioka, Masao, Yasushi Kawaguchi and Yoshiharu Doi, Alcaligenes eutrophus producing 3-hydroxybutyrate and4-hydroxybutyrate ("Production of Biodegradable polyesters and4-hydroxybutyrate," (Biotechnology) (569: Biotechnology). The chemical structure of P (3HB-co-3HV) is as follows:

in addition, 3-hydroxypropionate, 4-hydroxybutyrate and 4-hydroxyvalerate have been found to be novel components of bacterial Polyhydroxyalkanoates (PHAs), and have gained much attention in a wide range of fields such as marine, agricultural and medical applications. Recently, microbial synthesis of copolyesters P (3HB-co-4HB) of [ R ] -3-hydroxybutyrate and4-hydroxybutyrate by Alcaligenes eutrophus, Comamonas and Alcaligenes has been investigated. The chemical structure of P (3HB-co-4HB) is as follows:

when 4-hydroxybutyric acid is used as the sole carbon source for Alcaligenes eutrophus, P (3 HB-co-34% 4HB) containing 34% 4HB will be produced; when 4-hydroxybutyric acid containing some additives is used as a carbon source for Alcaligenes eutrophus, P (3HB-co-4HB) copolyesters containing a large amount of 4HB (60-100 mol%) are produced. It was also found that Alcaligenes latus efficiently produced P (3HB-co-4HB) random copolymer in a nitrogen-free environment using sucrose and 1, 4-butyrolactone as carbon sources during one-step fermentation. As the 4HB content increased, the tensile strength of the P (3HB-co-4HB) film decreased from 43MPa to 26MPa, while the elongation increased from 4% to 444%. On the other hand, as the 4HB content increased from 64% to 100%, the tensile strength of the film increased from 17MPa to 104MPa with increasing 4HB (Saito, Yuji, Shigeo Nakamura, Masayaharirumitsu and Yoshiharu Doi, "poly-3-hydroxybutyrate-4-hydroxybutyrate copolymer" ("Microbial Synthesis and Properties of Poly (3-hydroxybutyutyrate-co-4-hydroxybutyrate)," International Polymer International (Polymer International)1996 at No. 39 and No. 174. Studies found that as the 4HB content increased from 0 to 49 mol%, the crystallinity of P (3HB-co-4HB) decreased from 55% to 14%, indicating that the 4HB unit could not crystallize in the 3HB unit sequence and would become a defect in the P (3HB) lattice, this is likely to be a negative responsibility for P (3HB-co-4HB) and for increasing toughness relative to P (3HB) and for increasing 4HB, as the 4HB content increased from 0 to 18 mol%, the melting point decreased from 178 ℃ to 150 ℃ (Kunioka, Masao, Akira Tamaki and Yoshiharu Doi, the crystallization and Thermal Properties of Bacterial copolyesters: Poly-3-hydroxybutyrate-3-hydroxyvalerate copolymer and Poly-3-hydroxybutyrate-4-hydroxybutyrate copolymer ("Crystalline and Thermal Properties of Bacterial polyesters: Poly (3-hydroxybutyric-co-3-hydroxyvalerate) and Poly (3-hydroxybutyric-co-4-hydroxybutyrate),") Macromolecules (Macromolecules) 694-. It was also found that when 4HB units are present in P (3HB-co-4HB), the rate of biodegradation increases (Kunioka, Masao, Yasushi Kawaguchi and Yoshiharu Doi, Biodegradable copolyesters for the Production of 3-and 4-hydroxybutyrate by Alcaligenes eutrophus ("Production of Biodegradable polyesters of 3-hydrobutyrate and 4-hydrobutyrate by Alcaligenes eutrophus", Appl. Microbiolechnol) applied microbiology at 30 < 9 > -573. 1989). In another study, enzymatic degradation of P (3HB-co-4HB) membranes was performed in 0.1M extracellular depolymerase (purified from Alcaligenes faecalis) phosphate buffer at 37 ℃ and as a result, the rate of enzymatic degradation was found to increase significantly with increasing 4HB content, with the highest rate being 28 mol% 4HB (Nakamura, Shigeo and Yoshiharu Doi, Microbial Synthesis and characterization of Poly-3-hydroxybutyrate-4-hydroxybutyrate copolymers ("Microbial Synthesis and catalysis of Poly (3-hydroxybutyrate-co-4-hydroxybutyrate)") Macromolecules, Vol.85, Vol.17, 1992, p.4237-4241).

This may be due to a decrease in crystallinity of the synthesized product; however, the presence of 4HB in copolyesters above 85 mol% inhibits enzymatic degradation (Kumaai, Y. Kanesawa and Y. Doi, high molecular chemistry (Makromol. chem), Microbial Synthesis and Characterization of poly-3-hydroxybutyrate-4-hydroxybutyrate copolymers at 193 p 53 of 1992, Shigeo and Yoshiharu Doi ("Microbial Synthesis and catalysis of Poly (3-hydroxybutyrate-co-4-hydroxybutyrate)") Macromolecules (Macromolecules), vol.85 at 17 p 4237 and 4241 of 1992). In a comparison of the degradation rates of the P (3 HB-co-9% 4HB), P (3HB) and (HB-co-50% 3HV) films, it was found that P (3 HB-co-9% 4HB) was completely degraded in activated sludge within 2 weeks, the degradation rate of the biopolyester was much faster than the other two. The degradation rate of P (3HB) is faster than that of P (HB-co-50% 3HV) films (Kunioka, Masao, Yasushi Kawaguchi and Yoshiharu Doi, Biodegradable copolyesters for the Production of 3-and 4-hydroxybutyrate from Alcaligenes eutrophus ("Production of Biodegradable polyesters of 3-and 4-hydroxybutylate by Alcaligenes eutrophus,") applied microbiology (applied. Microbiol Biotechnol) at 30 nd 569. sup. 573 1989).

Poly (butylene terephthalate) (PBAT) is a biodegradable polymer that is not currently produced by bacteria, but is synthesized from petroleum products. Although PBAT has a melting point of 120 ℃ lower than PLA, it has high flexibility, excellent impact strength, and good molding processability. Furthermore, some studies on biodegradation of PBAT films and molded products have shown that significant degradation occurs in soil, seawater and water with activated sludge for one year. Although PLA has good processability, strength, and biodegradability/compostability, it has low flexibility and low impact strength. Mixing PBAT and PLA can improve the flexibility, softness and impact strength of the final product. It was found that the minimum suitable mixing ratio of PBAT and PLA was 50/50. However, the miscibility and hence the mechanical properties of the 50/50 mixture of PBAT and PLA can be improved by applying ultrasonic energy to the molten mixture by means of an ultrasonic device for 20 to 30 seconds. In this study, the tensile strength increased with increasing sonication time, reaching a maximum at 20 seconds and beginning to decrease after 20 seconds; while the impact strength increases to the maximum at 30 seconds and then gradually decreases with time. However, the impact strength of the sonicated systems is much higher than that of the non-sonicated systems. This can be explained by the fact that in the sonicated system, the excess energy is dissipated by plastic deformation of the PBAT phase, whereas in the untreated system, the phases are separated because they cannot mix and the propagating pressure passes around the PBAT phase. This can be seen from Scanning Electron Microscope (SEM) images, where the domain size reached a minimum of 4.7 μm after 30 seconds of sonication, but then increased significantly with time. It is hypothesized that the residual energy causes flocculation of the crystalline domains (Lee, Sangmook, young joo Lee and Jae Wook Lee, "Effect of ultrasound on the Properties of Biodegradable Polymer blends of Poly (lactic acid) with Poly (butyl acrylate-co-repeat), v Macromolecular Research, v.15, No.1, pp 44-50[2007 ]). as indicated above, PBAT has excellent elongation at break, above 500%, compared to PLA of only 9%, PHBV of only 15% (" Biodegradable polyesters: PLA, PCL, PHA "…, http: html) thus in addition to increasing the flexibility, extensibility and softness of films, packaging materials and fabrics made after mixing PBAT with PLA or PHA, pressing PBAT films into elastic biodegradable or non-biodegradable elastic fabrics will produce laminates with good extensibility.

PBAT has commercial products available, Ecoflex from BASF corporation^TMEastman chemical CoAnd Novamont, ItalyDuPont is selling a biodegradable aromatic copolyester known asIt is not PBAT but a modified polyethylene terephthalate with a high terephthalic acid content and with a high temperature of 200 ℃. Like the PLA, the amount of the binder is,hydrolysis must first be carried out before biodegradation, starting from the absorption and mineralization of small molecules by naturally occurring microorganisms (Vmean, Isabelle and LauTighzer, "Biodegradable Polymers," Materials 2009, 2, 307-. In 2004, Novomont purchased Eastar Bio copolyester from Eastman Chemical ("Novamont buys Eastman's Eastar Bio technology" http:// www.highbeam.com/doc/1G1-121729929. html). BASF corporation notes its PBAT-Ecoflex^TMIs highly compatible with natural materials, such as starch, cellulose, lignin, PLA and PHB ("Bio-sensor or Nonsense," Kunstoff International 8/2008[ transformed from Kunstoff 8/2008, pp.32-36).

Polybutylene succinate (PBS) and its copolymers belong to the family of poly (dicarboxylic acid) glycols. They are prepared by reacting diols (e.g. ethylene glycol and1, 4-butanediol) and an aliphatic dicarboxylic acid (like succinic acid or fatty acid). They are commercially available from Showa High Polymer, JapanAnd Ire Chemical Co of KoreaDifferent dicarboxylic acid diol esters were produced, including PBS, polyethylene succinate (PES) and copolymers made by adding fatty acids (polybutylene succinate-co-adipate, PBSA). Further, a copolymer prepared from 1, 2-ethanediol and 1, 4-butanediol with succinic acid and fatty acid has been commercially sold by SK Chemical of KoreaAnother aliphatic copolyester sold by Nippon Shokubai, Japan, is LunorePBS is a crystalline polymer with a melting point of 90-120 c, a glass transition temperature (Tg) of about-45 c to-10 c, between the Tg values of Polyethylene (PE) and polypropylene (PP), and it has similar chemical properties as PE and PP. It had a tensile strength of 330kg/cm2 and an elongation at break of 330%. The processability is better than that of PLA (Vmean, Isabelle and LauTighzert, "Biodegradable Polymers," Materials 2009, 2, 307-. The chemical structure of PBS is as follows:

PBS composed of succinic acid can also be produced by bacteria. China Sinoven Biopolymers utilizes biobased succinic acid to produce PBS with 50% renewable components. It is reported to have better performance than other biodegradable polymers and to have a heat resistance above 100 ℃ ("Production of biobased polybutylene succinate (PBS)", http:// biopol. free. fr/index. php/Production-of-biobased-polybutylene-succinate-PBS /). PBS is mixed in PLA to improve bending properties, heat distortion temperature, impact strength and gas permeability. PBS can be miscible with PLA when the PBS concentration is less than 20%, and this can reduce PLA brittleness (Bhatia, Amita, Rahul k. gupta, Sati n. bhattacharya and h.j. choi, "Compatibility of biodegradable poly (lactic acid) (PLA) and poly (butyl styrene) (PBS) blends for packaging application," Korea-Australia rhelogy journal, November 2007, vol.19, No.3, pp.125-131).

Disclosure of Invention

The invention aims to solve the technical problem of providing a biodegradable film and a laminated material which have long shelf life in clean environment and accelerate degradation in dirty environment aiming at the defect of slow degradation rate of the existing biodegradable material.

The technical scheme adopted by the invention for solving the technical problems is as follows: constructing a biodegradable film, which comprises PHAs and PLA, wherein the content of PLA is 1 to 95 percent by mass percent.

Mixtures of PHAs and PLA giving products with enhanced biodegradability are made from PHAs-PLA.

In a preferred embodiment of the invention, the shelf life of products made from the mixture of PHAs and PLA is increased in a clean environment.

In a preferred embodiment of the invention, the products made from the PHAs and PLA blend are thermoformed, injection molded or melt spun to produce films, containers for solids and liquids, rigid or flexible packaging, woven, knitted and non-woven fabrics in filament and staple form, and composite products of fabrics and films.

In a preferred embodiment of the present invention, the nonwoven fabric made by melt spinning includes a non-stick nonwoven fabric and a melt-blown nonwoven fabric.

In a preferred embodiment of the invention, the nonwoven fabric is made by wet bonding or dry bonding, including carding and air layering.

In a preferred embodiment of the invention, the nonwoven fabric is bonded using a wet adhesive, such as latex, or a dry adhesive, such as a thermal bonding powder or fibers.

In a preferred embodiment of the invention, the nonwoven fabric is obtained by a needle-punching process, a spunlacing process, hot calendering, thermal bonding with hot air jets-air or by the following heat treatment: microwave, ultrasonic, welding, far infrared and near infrared heating.

In a preferred embodiment of the invention, the fabric comprises: laminates using spunbond, spunbond-meltblown-spunbond alone may be used in industrial and medical protective garments such as hospital operating room drapes and gowns, as well as sterile equipment packaging, patient drapes and stretchers.

In a preferred embodiment of the invention, the aforementioned composite fabric is a laminate of film and fabric, and incorporates other nonwoven production processes such as spunlaying, needling, pulp or fiber air layering, and hydroentangling.

In a preferred embodiment of the invention, the laminate comprises a meltblown air filter and meltblown liquid filter media, as well as a spunbond or other nonwoven fabric as the outer or inner surface, which need only be stitched, thermally bonded or ultrasonically bonded at the edges.

In a preferred embodiment of the invention, the composite comprises MB PLA and a mixture of MB PLA with PHAs and cellulosic fibres, such as pulp or short cotton fibres or other artificial or natural fibres, added to the meltblown fibre stream or layer between MB layers.

In a preferred embodiment of the invention, the PHAs are PHBs or PHVs, or copolymers or blends of PHBs and PHVs.

In a preferred embodiment of the present invention, the PHBs are P (3HB-co-4HB) polymerized from 3HB and4 HB.

In a preferred embodiment of the invention, the mole percentage of 4HB is 5% to 85%.

In a preferred embodiment of the invention, the percentage of PLA in the dry mixture or composite, melt-extruded blend with PHAs ranges from 1% PLA to 95% PLA, preferably in the range of 50% or less, most preferably 30% or less (50% -10%) PLA.

In a preferred embodiment of the invention, the biodegradable and compostable woven, knitted and nonwoven fabrics, as well as film products of the invention, have improved mechanical properties, elongation, flexibility and impact resistance when the mixture of PBAT and PLA contains 5-60% PBAT, preferably 20-40% PBAT.

In a preferred embodiment of the invention, biodegradable and compostable woven, knitted and nonwoven fabrics, as well as film products, have improved mechanical properties, elongation, flexibility and impact resistance when the mixture of PBS and PLA contains 5-40% PBS, preferably 10-40% PBS.

In a preferred embodiment of the invention, biodegradable and compostable woven, knitted and non-woven fabrics, as well as film products, with improved mechanical properties, elongation, flexibility and impact resistance, when the mixture of PBAT with PBS and PLA contains 5-50% PBAT and 5-40% PBS, preferably 10-30% PBAT and 10-30% PBS.

In a preferred embodiment of the invention, the PBAT film has improved strength, reduced heat shrinkage and reduced cost when mixed with 10-60% PLA, preferably 20-40% PLA.

In a preferred embodiment of the invention, the PBAT film has improved strength, reduced heat shrinkage and reduced cost when mixed with 10-60% PBS, preferably 20-40% PBS.

In a preferred embodiment of the invention, the PBAT film when mixed with 10-40% PLA and 10-40% PBS, preferably 15-30% PLA and 15-30% PBS, has improved strength, reduced heat shrinkage and reduced cost.

In a preferred embodiment of the invention, the aforementioned biodegradable and compostable woven, knitted and nonwoven fabrics, as well as film products, are cost-reduced when mixed with fillers in an amount of 5 to 60% by weight, preferably 10 to 40% by weight, such as starch and calcium carbonate.

In a preferred embodiment of the invention the aforementioned biodegradable and compostable PBAT films are less costly when mixed with fillers in an amount of 5-60%, preferably 10-40% by weight, such as starch and calcium carbonate.

In a preferred embodiment of the invention, knitted, woven or non-woven fabrics made by adding 5-60% filler, preferably 10-40%, PLA, e.g. starch and calcium carbonate, are less costly.

In a preferred embodiment of the invention, the cost of the woven, woven or non-woven fabric produced by adding 5-60% filler, preferably 10-40%, of a mixture of PLA and PHA, such as starch and calcium carbonate, is low.

In a preferred embodiment of the invention, films made by adding 5-60% filler, preferably 10-40%, such as starch and calcium carbonate to PBS are less costly.

In a preferred embodiment of the present invention, the various biodegradable and compostable fabrics previously described may be laminated together to obtain a laminate.

In a preferred embodiment of the invention, laminates of various biodegradable and compostable fabrics may be bonded using biodegradable glues or hot melt adhesives.

In a preferred embodiment of the invention, the fabric is used as a shear mulch to inhibit weed growth, enhance moisture control, increase soil temperature and reduce fertilizer leaching.

In a preferred embodiment of the invention, the film is used as a shear mulch to inhibit weed growth, enhance moisture control, increase soil temperature and reduce fertilizer leaching.

In a preferred embodiment of the invention, the fabric and film laminate can be used as a shear mulch to inhibit weed growth, enhance moisture control, increase soil temperature and reduce fertilizer leaching.

In a preferred embodiment of the invention, the aforementioned laminate may be used in patient slings and stretchers.

In a preferred embodiment of the present invention, the aforementioned laminate can be used for disposable diapers and feminine sanitary napkins.

In a preferred embodiment of the invention, the laminate is made from a PBAT film and an elastomer-blown or spunbonded nonwoven made from ExxonMobilMade, either with 100% Vistamaxx or with a blend of 60-95% Vistamaxx and other polymers, such as polypropylene.

In a preferred embodiment of the invention, the laminate is made from a PBAT film and an elastomer-blown or spunbonded nonwoven made from ExxonMobilMade, either with 100% Vistamaxx or with a blend of 60-95% Vistamaxx and other polymers, such as polypropylene. Wherein the laminates are bonded together with glue or a hot melt adhesive.

In a preferred embodiment of the invention, theLaminates made from PBAT films and stretch-blown or spun-bonded nonwovens from ExxonMobilMade, either with 100% Vistamaxx or with a blend of 60-95% Vistamaxx and other polymers, such as polypropylene. Wherein the laminate is thermally bonded.

In a preferred embodiment of the invention, the laminate is made from a PBAT film and an elastomer-blown or spunbond nonwoven, which is made by ExxonMobilMade, either with 100% Vistamaxx or with a blend of 60-95% Vistamaxx and other polymers, such as polypropylene. Wherein the PBAT film is bonded to Vistamaxx by extrusion coating.

The invention discloses a reinforced biodegradable fabric and laminate made of a laminated biodegradable film mainly comprising PBAT (polybutylene terephthalate adipate) or PBS or a mixture of PBAT and PBS, and PLA and other degradable high molecular polymers such as PBSA, PCL-BS and PHA, thereby making PLA, and novel mixtures of PLA and PHAs, or mixtures of PLA, PBAT and PBS, or mixtures of PLA and PHAs, PBAT, PBS or other degradable high molecular polymers. These new fabrics and laminates have enhanced biodegradability in microbial-containing environments and can possess good shelf life and good strength, flexibility and flexibility. The base fabric used as a laminate is a woven, knitted or nonwoven fabric. The biodegradable film can be prepared by a film blowing process, a film casting process, a thermoforming process, vacuum forming or an extrusion coating process. In extrusion coating of films onto fabrics, binders are generally not necessary, but are required in most other processes. It is necessary to select an adhesive that is also biodegradable or to use a hot melt process to bond the film to the fabric.

Detailed Description

Although poly-3-hydroxybutyrate and poly-4-hydroxybutyrate polyester (P (3HB-co-4HB)) are easily degraded in soil, sludge and seawater, the degradation rate is very slow in water lacking microorganisms (Saito, Yuji, Shigeo Nakamura, Masaya Hiramitsu and Yoshihiharu Doi), "microbial synthesis and performance of poly (3-hydroxybutyrate-4-hydroxybutyrate" ("39 (1996)), 169 one 174). Therefore, the P (3HB-co-4HB) product has a very long shelf life in a clean environment, such as dry storage in a sealed package or storage in a wet tissue cleaning solution, and the like. However, fabrics, films and packaging materials of discarded P (3HB-co-4HB) are very susceptible to degradation when exposed to microbial-containing fouling environments, such as soil, river water, river mud, manure sand humus, sludge and sea water. It should be noted that polylactic acid (PLA) is not readily degraded in the above mentioned dirty environment, but is easily degraded. The heat and moisture in the humus first breaks down the PLA polymer into shorter polymer chains and eventually degrades to lactic acid. The humus and soil microorganisms then consume the small polymer fragments and lactic acid as nutrients.

Thus, mixing hydroxybutyrate esters (PHAs) with PLA will accelerate the degradation rate of PHAs-PLA blended products, such as P (3HB-co-4 HB). Furthermore, by mixing PHAs and PLA, the shelf life of the product in a clean environment will be extended. Although the price of PLA has dropped significantly over the last 10 years, only slightly above synthetic polymers (such as polypropylene and PET polyester), the price of PHAs remains as high as 2 to 3 times the price of PLA. This is because PLA can be made by large-scale synthesis of lactic acid, whereas PHAs are produced by bacteria in combination with specific carbon sources and must be extracted from the bacteria by solvents. Therefore, melt-extruded products (such as woven and knitted fibers, non-woven fabrics, films, food packaging containers, and the like) if more than 25% PHA is mixed in PLA would not be suitable for commercial use.

The formulations of the four groups of sample solutions are shown in tables 1, 2, 3 and4, respectively. These samples were 400Kg, respectively: the wet towel cleaning solution (usually the liquid in the wet towel package for babies), water collected from Dongjiang of Dongguan of China with some river mud, river mud collected from Dongjiang of China and mixed humus produced by sludge/sand/and cow dung are mixed and diluted with distilled water, and the pH value is adjusted to be more than 7 by potassium hydroxide. Wherein each treatment process used two sample solutions of the same formulation, and each treatment chamber containing the treated sample was capped and tested for PH and percent solids every 2 weeks. The average results of the samples treated in the first 4 weeks are shown in table 5.

In one embodiment of the invention, 25Kg of a blend of 85% PLA (2002D manufactured by NatureWorks Corp.) and 15% PHB (3HB-co-4HB), and 25Kg of a blend of 75% PLA (2002D manufactured by NatureWorks) and 25% PHB (3HB-co-4HB) are melt mixed together and extruded into pellets and shipped to Biax-Fiberflilm of Greenville, Wisconsin, USA and then melt spun to produce a melt blown nonwoven (MB) fabric weighing about 50g/m². For comparative testing, 100% PLA (2002D manufactured by NatureWorks) MB fabric was also made. During the melt-blowing of these polymers, it is increasingly evident that the temperature of the melting and hot gases used to make MB fabrics is too high, because the 2002D PLA polymer has a very low melt index (indicating that PLA has a very high molecular weight), and very high temperatures are required to increase the flowability of the PLA so that it can be smoothly extruded from the melt-blowing die orifice. Melt temperature of 274 ℃ for 100% 2002D PLA and 276 ℃ for hot gas flow compared to 266 ℃ for melt blown spunbond grades with melt coefficients of 70-80 and 260 ℃ for hot gas flow (Wadsworth, Larry and dog Brown, "High Strength, High Quality Meltbloom Insulation, Filters and wires with Low Energy," published in the Guangdong Association of nonwovens, Guangdong, China, 2009, generally used melt blown PLA26-27 days 11 months). Thus, with the two mixtures described above, the contained PHB component is significantly subject to thermal degradation, as evidenced by the high smoke emission in the extruded MB fibres and the low strength of the produced MB PLA/PHB fabrics. Subsequent trials were designed to blend PHB with PLA polymer (PLA 6251D from NatureWorks, inc.) with a higher melt index (MI 70-85, which requires much lower MB processing temperatures) in the same proportions. Furthermore, it is expected that the same composition produced using 6251DPLA on a 1 meter non-tacky nonwoven test line, typically operating at a temperature slightly above the melting point of the PLA and mixed PLA-PHB polymers, will result in less thermal degradation. This is because it employs a filament drawing step in the SB process, which is not included in the MB process, and therefore produces filaments that are significantly larger than MB filaments produced using the same polymer, although the average diameter of the fibers in the SB web is typically 12-25 μm, compared to 2-8um for MB webs. The second MB operation was carried out at 12 months 2010 using a more compatible blend of PLA6251D with PHB, in the proportions 85% PLA/15% PHB and 75% PLA/25% PHB. The melting temperature required for these two new blends was lower, 231 ℃ with the hot air temperature of the 85% PLA/15% PHB blend also being lower, 233 ℃ and the hot air temperature of the 75% PLA/25% PHB blend being only 227 ℃. Also, spray-fusing the new PLA/PHB blend at low temperatures will result in less smoke and odor pollution. In addition, the samples were whiter, softer, and stronger than the first MB run described above. In 12 months 2011, these same polymer composites would run on a 1.0m Reicofil4 SB line, which would minimize the effects of thermal degradation, such that the degradation observed during the biodegradation process is primarily from biodegradation. Furthermore, due to the large difference in diameter between MB and SB nonwoven fibers, smaller MB fibers will have a larger surface area, making it expected to biodegrade more readily and more rapidly.

MB 100% 2002D type MB Fabric, 85% 2002D type PLA/15% PHB and 75% 2002D/25% PLA were rolled into 12.5 inches wide by 50g/m in a first MB operation²Heavy, transported from Biax-Fiberfilm corporation back to ChinaPacific non-weaving works of eastern guan (u.s.pacific nonwovens Industry). In which 1.5 meters of each fabric was selected for soaking in a different treatment method, then exposed to a different treatment solution along with the sample to be removed from each treatment chamber, and subjected to respective repetitions at 4 weeks, 8 weeks, 12 weeks, 16 weeks, and 20 weeks.

The test procedure was as follows, first applying a wet wipe cleaning solution to MB PLA and PLA-PHB fabrics and storing them in a porous steel basket, exposing them to a treatment cabinet, after four weeks of treatment, gently washing MB samples from humus in nylon socks, and after washing and drying, the degradation could be observed. The MB fabric was treated with river water in the same manner as the wet wipe cleaning solution and placed on a perforated steel basket in a lidded treatment cabinet, and 100% MB PLA, 85% PLA-15% PHB, and 75% PLA-25% PHB were removed from all treatment cabinets in increments of every 4 weeks until after 20 weeks. First, the fabric exposed to river mud and sludge/sand/manure humus is laid in a treatment tank and is immersed and completely penetrated by the treatment liquid. The fabric was then placed in nylon pantyhose, a 1.5 meter sample was added to one leg and the other half to the other, and the sock was then gently stretched over the sample, the sock containing the fabric was embedded in a suitable box containing river mud or humus, and each sock was attached to a label by nylon thread outside the treatment box. Every 4 weeks the removed fabric samples were placed in a metal box with a screen at the bottom, a nylon knitted fabric was placed on the screen, and the treated fabric was gently washed by applying a low pressure water spray directly on the palm of the hand. A second nylon knit fabric was then placed over the cleaned sample and gently turned over to the other side for cleaning. All treated fabrics were then placed on a laundry dryer for more than two days to dry until dried before being sent to the laboratory for testing. The results of the physical property tests of the fabrics after 4 weeks of different treatments are shown in the table, wherein Table 6A is a 100% 2002D PLA MB fabric, Table 7A is an 85% 2002D PLA/15% PHBMB sample, and Table 8A is a 75% 2002D/25% PHB fabric. The 100% MB PLA sample lost 6% of the mechanical tensile strength (MD) after 4 weeks of exposure to the wet wipe cleaning solution, while the 85% PLA/15% PHB and 75% PLA/PHB fabrics lost only 4% and 1% of the mechanical tensile strength, respectively, in the wet wipe cleaning solution. But the transverse mechanical trapezoidal tear resistance (cross machine direction (CD)) was lost to 50%, 32% and 65% for 100% PLA, 85% PLA/15% PHB and 75% PLA/25% PHB, respectively. After 4 weeks in river water, 100% MB PLA lost 26% of MD tensile strength and 64% CD tear strength, while 85% PLA/15% PHB and 75% PLA/25% PHB lost 19% and 22% MD tensile strength, and 77% and 80% CD tear strength, respectively. After 4 weeks in river mud, 100% PLA fabric lost 91% MD tensile and 98% CD tear strength, while 85% PLA/15% and 75% PLA/25% PHB lost 76% and 75% MD tensile, and 96% and 87% CD tear strength, respectively. After 4 weeks in sludge/sand/cow dung humus, 100% PLA fabric lost 94% MD tensile strength and 99% CD tear strength, while 85% PLA/15% and 75% PLA/25% PHB lost 76% and 86% MD tensile strength, and 99% and 83% CD tear strength, respectively. All samples exposed to river mud and humus have enhanced gas permeability with higher gas permeability values, indicating that more developed structures are produced as biodegradation increases. The increase in gas permeability of the MB 100% PLA fabrics treated individually was less than that of the PLA-PHB hybrid fabrics. There is no weight loss of the fabric, but in fact there is some increase because it is difficult to remove all of the process fragments without causing deeper damage to the fabric.

Tables 6B, 7B and 8B show the effect of exposure of 100% 2002D PLA MB fabric, 85% PLA/15% PHB and 75% PLA/25% PHB, respectively, after 12 weeks under different treatment conditions. After all of these fabrics were stored for 16 weeks on rolls wrapped in plastic, 85% PLA/15% PHB showed no significant decrease in MB toughness and CD toughness after 16 weeks of storage, while 75% PLA/25% PHB showed 22% loss in MB toughness and 33% loss in CD toughness. As after 4 weeks of exposure under different treatment conditions, the MD and CD toughness of the samples with 100% PLA was higher than the other two PLA and PHB blends in the wet wipe cleaning solution compared to the toughness of the corresponding home made fabrics after 12 weeks of exposure. All these samples were associated with considerable degradation after 12 weeks in river water, river silt and sludge/sand/manure humus.

TABLE 1 formulation of wet towel cleaning solution loaded in two different boxes

Composition (I)	Mass percent (%)	Quality (Kg)
			Pure water	97.56	390.24
Propylene glycol	1.2	4.8
			Lanolin	0.6	2.4
Cocoacyl diacetic acid	0.3	1.2
			Polystyrene-20	0.1	0.4
P-hydroxybenzoic acid ethyl ester	0.0167	0.0668
			P-hydroxybenzoic acid methyl ester	0.0167	0.0668
Propyl p-hydroxybenzoate	0.0167	0.0668
			Benzalkonium chloride	0.075	0.3
Ethylenediaminetetraacetic acid disodium salt	0.075	0.3
			Citric acid	0.01	0.04
Aromatic hydrocarbons	0.03	0.120
			Total of	100.0	400Kg (about 400L)

TABLE 2 river composition loaded by two cartridges

Composition (I)	Quality (Kg)
River water	380
		River mud	20

[0072]

Total of

400Kg

TABLE 3 river mud composition loaded in two cases

Composition (I)	Quality (Kg)
River mud	300
		River water	100
Total of	400

TABLE 4 Mass composition of sludge, sand, cow dung and distilled water loaded in the two cases

Table 4 illustrates:

69Kg of dry sludge (obtained from a river by the USP Garden) was added to a large mixing vessel; adding 69Kg of dried cow dung which is broken into small pieces by slow stirring with a large electric stirrer;

during mixing, 69Kg of dry sand is slowly added;

83Kg of distilled water is slowly added while stirring;

after complete mixing, the pH was checked using litmus paper or a pH meter and 10% sodium hydroxide (prepared with distilled water) was added slowly until the pH reached 7.5;

the remaining distilled water was added to make the total amount of water in the added calcium hydroxide 93Kg, and the pH was measured and adjusted to 7.5.

TABLE 5 pH and percent solids (%)

TABLE 6 A.100% PLA (2002D) weight, thickness, air permeability and Strength Properties after production and after 4 weeks of exposure to cleaning fluids, river water, river mud and silt/sand/manure humus

TABLE 7A weight, thickness, air permeability and Strength Properties of 85% PLA (2002D)/15% PHB after production and after 4 weeks of exposure to washing liquids, river water, river mud and sludge/sand/manure humus

TABLE 8A weight, thickness, air permeability and Strength Properties of 75% PLA (2002D)/25% PHB after production and after 4 weeks of exposure to wash, river water, river mud and silt/sand/manure humus

Table 6 b.100% PLA (2002D) MB cleaning wet wipes have weight, thickness, breathability and strength properties after 3 and 16 weeks of production and after 12 weeks of exposure to cleaning fluids, river water, river mud and silt/sand/manure humus

Too dispersed samples to be physically tested

TABLE 7 B.weight, thickness, air permeability and Strength Properties of 85% PLA (2002D)/15% PHB after 3 and 16 weeks of production and after 12 weeks of exposure in wash, river water, river mud and silt/sand/manure humus

Too dispersed samples to be physically tested

TABLE 8 B.weight, thickness, air permeability and Strength Properties of 75% PLA (2002D)/25% PHB after 3 and 16 weeks of production and after 12 weeks of exposure in wash, river water, river mud and silt/sand/manure humus

Too dispersed samples to be physically tested

In addition to the above biodegradation studies, pure PBAT films with a thickness of 9 μm and 9 μm PBAT films containing 20% calcium carbonate were also purchased from Chinese companies. Meltbwn (MB) containing 20% PP was obtained from Biax-Fiberfilm of Madison, USABlack carbon-black-containing Spunbond (SB) PLA from the German Saxon textile research institute and having a nominal weight of 80g/m². Pure PBAT film and PBAT film containing 20% calcium carbonate were each laminated with a hot melt adhesive containing 20% PPVistamaxxMB and black SB PLA, using 5-13g/m 2. Generally, 0.5 to 12g/m is used²Preferably 1 to 7g/m²The hot melt adhesive of (1). In addition, two layers of SB PLA were laminated and adhered together using hot melt adhesive. The results of the tests on weight, thickness, toughness, elongation at break, tear strength, burst strength, water vapor transmission rate and hydrogenation head for all these raw materials and laminates are shown in table 9. It should be noted that these are only some samples of different embodiments of the invention, which use hot-melt techniques to glue together different layers of material, the PBAT film or other biodegradable/humifiable film can be applied directly to the substrate by means of extrusion coating, without the need for using a glue. The laminates may be joined or bonded together using thermal spot light, bulk calendering, or ultrasonic welding techniques, to name just a few techniques. In addition, as an alternative to hot melt adhesives, glues, water or solvent based adhesives, or latex may also be used to adhere the laminates together.

As shown in table 9, the 9 μm pure (100%) PBAT film (sample 1) had good elongation in the MD direction and very high elongation in the CD, above 300%. None of samples 1 through 5 were able to be tested for burst strength because all of these samples were too elastic to allow the film and laminate to burst during testing and also did not significantly deform after testing. The water vapor transmission rate of sample 1 was very high and was 3380g/m²Per 24 hours, the hydrostatic head is 549 mm. The PBAT film containing 20% calcium carbonate (sample 2) performed similarly to sample 1 with the same water vapor transmission rate and slightly lower hydrostatic head. Similar to samples 1 and 2, the PBAT films had a slightly thinner thickness of 6 μm or less, but still had better elongation and higher water vapor transport rates, although the hydrostatic head may be lower. MB sample 3, namely 80%(Vistamaxx brand polypropylene based polymers are highly elastic, produced by ExxonMobil corporation) and 20% PP, have very high MD and CD elongation, about 300%, and a high water vapor transmission rate of 8816g/m when fully extended²And/24 hours. However, the hydrostatic head of sample 3 was very high, 1043mm, indicating that it still has very good permeability. It should be noted that 20% PP was added to Vistamaxx polymeric microspheres, physically mixed, and the mixture added to the MB extruder to melt, so that Vistamaxx MB fabric was not too sticky. If 100% Vistamaxx is melt blown, it has a very high viscosity, can clog rollers, and is very difficult to separate for lamination or subsequent use. However, if MB Vistamaxx is laminated in line with a film, such as PBAT or PBS with or without calcium carbonate, or other nonwoven, scrim or fabric, it is feasible to spray melt 100% Vistamaxx. In fact, it may not be necessary to use an adhesive because Vistamaxx at 100% Vistamaxx or higher concentrations is already very tacky.

Pure PBAT and PBAT containing 20% CaC03 with Vistamaxx laminated using hot melt adhesives exhibited significant increases in MD and CD toughness relative to Vistamaxx alone. This sample has high MB elongation, especially high CD elongation (390% for sample 4, 542% for sample 5). Samples 4 and 5 also had significantly high values for the water vapor transmission rate, 1671 and 1189g/m, respectively²24 hours, and higher hydrostatic head, 339 and 926mm H, respectively₂And O. It should also be noted that PBAT films may be extrusion coated directly onto MB 100% Vistamaxx or MB Vistamaxx containing some PP, with or without hot melt adhesives, and that the extrusion coating process may allow for thinner regular PBAT films, possibly even as low as 4 or 5 microns, and result in higher MVTR, but the hydrostatic head may be reduced.

Black SB PLA having a target weight of 80g/m and an MD toughness of 104N and a CD toughness of 31N, and having a lower MD elongation of 30.6% and a higher CD elongation of 30.7%. The destruction intensity is 177KN/m²The WVTR is very high and is 8322g/m²The hydrostatic head was very clearly 109mm at 24 hours. 80g/m black SB PLA, which was not laminated to pure PBAT using a hot melt adhesive, had MD and CD toughness higher than that of SB PLA alone, 107N and 39N, respectively. But its CD elongation was only 9.8%. However, PBAT laminated with SB PLA had a high burst strength of 220KN/m2, the air permeability was still good, and the water vapor transmission rate was 2459g/m²24 hours and has a hydrostatic head of 3115mm H2O. SB PLA laminated with PBAT containing 20% CaCO3 had similar performance as sample 8 except that the hydrostatic head, while still high, was 2600mm H2O, but was relatively low. Laminates of SB PLA with thinner PBAT films, especially laminates of SB PLA with thinner PBAT films obtained by extrusion coating deposition, produce protective garments for medical, industrial applications or sports that have a high MVTR for comfort of wear, while having a high hydrostatic head for acting as a protective barrier. The barrier can be further enhanced by applying a protective finish (fluorosilicone or other type of protective finish) to the PBAT film side, or either side of the SB OLA before or after lamination with the film. Another way of reinforcement is to laminate MB PLA with SB PLA either before or after lamination with the film. The repellent finish may also be added, for example, to PBAT films, SB or MB polymer melts.

When two layers of SB PLA were bonded together by melt adhesion to produce sample No. 9, the MD and CD tensile and burst strength were essentially twice that of the single layer of sample No. 6. From 110g/m²The tough slings produced from SB PP have target MD and CD tensile and responsive elongation to break (% elongation) values of at least 200 and 140N/5cm, respectively. Table 9 shows that the MD tensile of both adhered layers of SB PLA is 215N, but the CD tensile is only about 50% of the desired level. Also, the MD and CD% elongation values are well below the required minimum of 40%. The MD and CD elongation of SB PLA can be improved by incorporating 5-60% PBAT (preferably 25-50% PBAT) into the PLA prior to extrusion of the SB fabric. In addition, PBAT and PBS can be mixed with PLA to be made to have the desired propertiesMD and CD tensile and elongation values, and heat stable fabrics. In addition, SB webs can be bonded by a non-thermal point-and-point bonding process to achieve better multi-directional strength and elongation, including hydroentangling and needling. The needle-punched SB PLA can be used at 110g/m²Larger and heavier, and do not require two or more fabrics of SB PLA to be pressed or bonded together to achieve the desired strength and elongation values.

TABLE 9 PBAT film and Meltblown (MB)And Spunbond (SB) PLA, and the strength and barrier properties of a laminate of two layers of SB PLA

DNB stands for high elasticity and difficult to break

Claims (20)

1. A biodegradable film comprises PHAs and PLA, wherein the content of PLA is 1 to 95 percent by mass percent.

2. The biodegradable film according to claim 1, characterized in that said PLA is present in a percentage by mass ranging from 10% to 50%.

3. The biodegradable film according to claim 1, characterized in that said PHAs are PHBs or PHVs, or copolymers or blends of PHBs and PHVs.

4. The biodegradable film according to claim 3, wherein said PHBs is P (3HB-co-4HB) polymerized from 3HB and4 HB.

5. The biodegradable film according to claim 3, characterized in that said molar percentage of 4HB is between 5% and 85%.

6. The biodegradable film of claim 1, further comprising cellulose fibers.

7. The biodegradable film according to claim 1, characterized in that it is produced by thermoforming, injection molding or melt spinning, for film, containers of solids and liquids, rigid or flexible packaging, woven, knitted and non-woven fabrics of filaments and staple fibers, and composite products of fabrics and films.

8. The biodegradable film according to claim 7, characterized in that said melt spinning comprises a non-woven treatment of anti-sticking and melt-blowing.

9. The biodegradable film according to claim 7, wherein said nonwoven fabric is bonded by wet bonding or dry bonding.

10. The biodegradable film according to claim 7, characterized in that said non-woven fabric is obtained by a needle-punching process, a hydro-entangling process, a hot calendering, a hot air flow deposition or a heat treatment of: microwave, ultrasonic, welding, far infrared and near infrared heating.

11. The biodegradable film according to claim 7, wherein said composite product is a rolled film or fabric, combined with a spin deposition process, a needle punching process, an air deposition process or a water punching process of pulp or fibers.

12. The biodegradable film according to claim 11, characterized in that said rolling comprises a thermo-spunbond-meltblown-spunbond, or an ultrasonically bonded nonwoven process, said composite product being used in protective fabrics for industrial and medical use.

13. Biodegradable film according to claim 11, characterized in that said composite product comprises a melt-blown filtering medium with anti-adhesive as inner and outer surface, said product being sewn or heat-or ultra-sonically adhered at the edges of said melt-blown filtering medium.

14. A biodegradable laminate, characterized in that it comprises a biodegradable film according to any of claims 1-13, and PBAT.

15. Biodegradable laminate according to claim 14, characterized in that said biodegradable laminate contains 5-60% by mass of PBAT.

16. The biodegradable laminate according to claim 14, characterized in that said biodegradable laminate further comprises 5-60% by weight of a filler.

17. A biodegradable laminate, characterized in that it comprises a biodegradable film according to any one of claims 1-13, and PBS.

18. The biodegradable laminate according to claim 17, characterized in that said biodegradable laminate contains 5-40% by mass of PBS.

19. A biodegradable laminate, characterized in that it comprises a biodegradable film according to any of claims 1-13, and a mixture of PBAT and PBS.

20. The biodegradable laminate according to claim 19, characterized in that it contains 5-50% PBAT and 5-40% PBS in mass percentage.