TW201433601A - Degradable recycling material - Google Patents

Abstract

This invention relates to a novel biodegradable material prepared from PHAs and PLA polymers, which can be used for manufacturing a blended product of PHAs and PLA, and which can have accelerated biodegradation in an environment containing microorganisms. The novel product can be used for producing films, containers for solids and liquids, rigid or flexible packages, long-filament and short-fiber weaving, knitting and nonwoven fabrics, and composite products of fabrics, films and other materials by thermal forming, injection molding or melt spinning. These blends also can have a long shelf-life in a clean environment.

Description

Degradable recycled material

The present invention relates to a blend of polyhydroxyalkonates (PHAs) and polylactic acid (PLA) which are produced to enhance biodegradation in a microbial-containing environment. Another advantage of these blends is the extended shelf life in a clean environment where the film, solid and liquid containers, rigidity or can be produced by thermoforming, injection molding or melt spinning a blend of PHAs and PLA. Flexible packaging, woven, knitted and non-woven fabrics of filaments and staple fibers, as well as composite products of fabrics, films and other materials.

Over the past 20 years, polylactic acid has become a major biodegradable/corruptible polymer that can be used to make plastics and fibers. This is because although polylactic acid is derived from natural renewable materials, it has thermoplastic properties and can be melt extruded to produce plastic products, fibers or fabric products. These products have comparable mechanical strength and flexibility to petroleum-based composites such as polyolefins (polyethylene and polypropylene) and polyesters (polyethylene terephthalate and polyterephthalic acid). Ethylene glycol ester). Polylactic acid is made of lactic acid, which is a by-product of fermentation from corn (such as Zea mays), wheat (such as Triticum spp.), rice (such as Oryza sativa) or sugar beet (such as Beta vulgaris). Lactic acid forms a dimeric repeat unit having the following structure upon polymerization:

Unlike other synthetic fiber materials derived from plant sources, such as cellulose, PLA is more suitable for melt spinning into fibers. The preparation of PLA fibers by melt spinning can reduce economic and environmental costs relative to the solvent spinning process necessary for the synthesis of cellulose fibers, and the PLA produced has a wider range of properties. Like polyethylene terephthalate polyester (PET), PLA polymers need to be dried before melting to avoid hydrolysis during melt extrusion, and both can be passed from the polymer. The fibers are drawn (stretched) for better tensile strength. PLA molecules tend to exhibit a helical structure that makes them easier to crystallize. At the same time, its lactic acid dimer has three isomers: a left-handed type, which deflects polarized light in a clockwise direction; a right-handed type that deflects polarized light in a counterclockwise direction; and a racemic type, which has no optical activity. During the polymerization process, the relative proportions of these types can be controlled to control their important polymer properties more broadly. Control of thermoplastic "natural" fiber polymers, unique polymer morphology, and isomer content in polymers allows manufacturers to design a wider range of properties in fibers (Dugan, 2001 and Khan et al., 1995).

PLA does not decompose naturally when it is extruded. Instead, it must first be hydrolyzed before it becomes biodegradable. In order to allow a greater degree of hydrolysis of the PLA, it is necessary to simultaneously maintain the relative humidity equal to or higher than 98%, and the temperature is equal to or higher than 60 °C. Once these conditions are met, degradation occurs rapidly (Dugan, 2001 and Lunt, 2000). However, the composition and arrangement of the three isomers can be controlled by controlling the melting temperature between 120 ° C and 175 ° C, and if the melting temperature is low, the polymer will be completely amorphous. Adding enzymes and microorganisms to the melt will result in more amorphous polymers.

Polylactic acid has been used to make many different products, and factors controlling its stability and rate of degradation have also been documented in many literatures. Both L-lactic acid and D-lactic acid produced during fermentation can be used to produce PLA (Hartmann, 1998). One advantage of PLA is that its degradation rate can be controlled by changing factors such as the ratio of right-handed and left-handed forms, molecular weight or crystallinity (Drumright et al., 2000). For example, Hartmann discovered in 1998 that unstructured polylactic acid samples degraded rapidly into lactic acid in a few weeks, but high crystallinity materials can take months to years to fully degrade. This flexibility and control makes PLA a very useful raw material for the production of agricultural mulch fabrics, where the material degrades in the ground after a certain period of time (Drumright et al., 2000).

Polylactic acid is decomposed into small molecules by different mechanisms, and the final decomposition products are CO ₂ and H ₂ O. The degradation process is affected by temperature, humidity, pH and enzymes as well as microbial activity, but is not affected by UV light (Drumright et al., 2000; Lunt, 2000). In early work on the evaluation of PLA degradation for biomedical applications, Williams discovered in 1981 that pineapple protease, pronase and proteinase K can accelerate the rate of PLA decomposition. Recently, Hakkarainen et al. in 2000 incubated a 1.8 mm thick PLA sample at 86 °F in a microbial mixed culture extracted from humus. After 5 weeks of incubation, the humic treated film degraded into a fine powder, while the untreated control group remained intact. It should be noted that this study only used the left-handed form, and the rate of degradation will vary with the proportion of the left-handed and right-handed forms. In any case, the work of Hakkarainen et al. in 2000 showed that the application of a large number of microorganisms that are easily obtained from humus can accelerate decomposition. Currently, PLA degradation studies are performed in both in vitro liquid cultures and in active humic operations above 140 °F (Drumright et al, 2000; Hakkarainen et al, 2000; Lunt, 2000; Williams, 1981). When PLA is made into humic substances at 140 °F, it degrades rapidly and can almost reach 100% biodegradation in 40 days (Drumright et al., 2000), but when it is below 140 °F, when the fabric is in contact with soil organic matter. Its stability has yet to be determined. Larry Wadsworth (Khan et al., 1995) of the University of Tennessee in the United States first began researching spunbond (SB) and meltblown (MB) nonwoven fabrics made using PLA (Smith, BR, LC Wadsworth (speaker), MGKamath, A.Wszelaki, and CESams, developing the next generation of biodegradable Mulch Nonwovens to Replace Polyethylene Plastic ("Development of Next Generation Biodegradable Mulch Nonwovens to Replace Polyethylene Plastic", 2008 International Conference on Sustainable Textiles ( ICST 08)), Wuxi, China, October 21-24, 2008, CD-ROM.

Biodegradable polymers are required to be resistant to many environmental factors during their effectiveness, but are required to be biodegradable when discarded. The biodegradation of PLA was studied under aerobic and anaerobic, water and solid conditions at different elevated temperatures. The study found that PLA is very slow to biodegrade at room temperature when exposed to an aerobic water environment, but biodegrads faster at high temperatures. The above findings are also supported by the fact that the PLA must be hydrolyzed before the microorganism can use it as a source of nutrients. At the same elevated temperature, the biodegradation of PLA under anaerobic solid state conditions is much faster than under aerobic conditions. The behavior of PLA during natural humification Similar to exposure to degradation in water, biodegradation only begins after it has been heated. These results reinforce a widely held view that PLA is compostable and stable at mesophilic temperatures, but degrades rapidly during waste treatment of compost or anaerobic treatment equipment (Itavaara, Merja, Sari Karjomaa and Johan-Fredrik Selin, "Biodegradation of Polylactide in Aerobic and Anerobic Thermophilic Conditions" ("Elsevier Science Ltd") .), 2002). In another study, the biodegradation level of anaerobic digestion sludge for different plastics was determined and compared with simulated landfill conditions. Bacterial poly-93-hydroxyvaleric acid Salt (PHB/PHV), a natural aliphatic polyester produced by bacteria, is completely degraded in anaerobic digestion sludge for almost 20 days; however, aliphatic polyester PLA synthesized from natural materials, and two others The evaluated aliphatic polyesters: polybutylene succinate and polybutylene succinate-polyethylene succinate copolymers did not undergo any degradation after 100 days. A cellulose control The cellophane degradation in 20 days was similar to that of PHB/HV. In addition, PHB/HV degraded well under simulated landfill conditions for 6 months (Shin, Pyong Kyun, Myung Hee Kim and Jong Min Kim, biodegradable plastic exposure) "Biodegradability of Degradable Plastics Exposed to Anaerobic Digested Sludge and Simulated Landfill Conditions," Journal of Polymers and the Environment, 1997 Volume 5, Issue 1, 1566-2543).

In the study of true biodegradable polymers, poly(hydroxyalkonate)s, PHAs have been found to be naturally synthesized by many bacteria as intracellular carbon and energy storage materials. As early as the 1920s, poly-(R)-3-hydroxybutyrate (P(3HB)) was isolated from B. megacephalum and subsequently identified as Bacterial reserve polyester. However, P(3HB) did not show significant commercial value because it was found to become brittle and hard after a long period of time, so it could not be used to replace mainstream synthetic polymers, polyethylene (PE) and polystyrene. Ethylene (PS). Finally, other hydroxalkonate (HA) units, which are different from 3HB, are found in microbial polyesters. When it is contained in P(3HB), it can improve its mechanical properties and thermal properties. The research and commercial interests of polyester have had a major impact. Biodegradability in the natural environment is one of the unique properties of PHA materials. Microbial polyesters are biodegradable in soil, sludge or seawater. Because PHA is a solid polymer with a high molecular weight, it cannot be transported well through the cell wall as a nutrient. Therefore, microorganisms such as fungi and bacteria secrete extracellular degrading PHA enzymes, called PHA degrading enzymes, which hydrolyze solid PHA into water-soluble oligomers and monomers that can be transported to cells and subsequently Metabolized as a source of carbon and energy (Numata, Keiji, Hideki Abe and Tadahisa Iwata, Biodegradability of Poly (hydroxalkonate Materials, Materials), Materials, 2009 2 issues 1104-1126 pages). A random copolyester of [R]-3-hydroxybutyrate and [R]-3-hydroxyvalerate, P(3HB-co-3HV) in Imperial Chemical Industry Group (Imperial Chemical) Industries, ICI) have been commercialized. Studies have shown that Oxygen-producing bacteria produce a photoactive copolyester of 3-hydroxybutyrate (3HB) and 3-hydroxyvalerate (3HV) using propionic acid and glucose as carbon sources (Holmes, PA (1985), PHB application: "Applications of PHB: a Microbially Produced Biodegradable Thermoplastic," Phys Technol 16:32-36 from Kunioka, Masao, Yasushi Kawaguchi and Yoshiharu Doi, a bacterium producing a biodegradable copolyesters of 3-hydroxybutyrate and 4-hydroxybutyrate by Alcaligenes eutropus Applied Microbial Technology (Appl. Microbiol Biotechnol) (1989) 30: 569-573). 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 new components of bacterial polyhydroxyalkanoates (PHAs) and have gained widespread marine, agricultural and medical applications. Many concerns in the field. Recently, a microorganism of [R]-3-hydroxybutyrate and 4-hydroxybutyrate copolyester P(3HB-co-4HB) was carried out by cultivating bacterium, C. mobilis and Bacillus licheniformis Synthesis has been studied. The chemical structure of P(3HB-co-4HB) is as follows:

When 4-hydroxybutyric acid is used as the sole carbon source for the eutrophic bacterium, 34% 4HB of P(3HB-co-34% 4HB) will be produced; and when it contains some additives, 4-hydroxybutyric acid When used as a carbon source for the bacterium, the P(3HB-co-4HB) copolyester containing a large amount of 4HB (60-100 mol%) will be produced. It has also been found that in a nitrogen-free environment, the eutrophic bacterium produces a P(3HB-co-4HB) random copolymer efficiently using sucrose and 1,4-butyrolactone as a carbon source in a one-step fermentation process. With the increase of 4HB content, the tensile strength of P(3HB-co-4HB) film decreased from 43Mpa to 26Mpa, and the elongation increased from 4% to 444%. On the other hand, as the 4HB content increases from 64% to 100%, the tensile strength of the film increases from 17Mpa to 104Mpa with the increase of 4HB (Saito, Yuji, Shigeo Nakamura, Masaya Hiramitsu and Yoshiharu Doi, "Poly-3- Bacterial Synthesis and Properties of Hydroxybutyrate-4-Hydroxybutyrate Copolymer ("Microbial Synthesis and Properties of Poly(3-hydroxybutyrate-co-4-hydroxybutyrate)," International Polymer (Polymer International), 1996 39, pp. 169-174. The study found that as the content of 4HB increased from 0 to 49 mol%, the crystallinity of P(3HB-co-4HB) decreased from 55% to 14%, indicating that 4HB units cannot be in 3HB. The unit sequence crystallizes and becomes a defect in the P(3HB) lattice. This is likely to be responsible for the reduction of P(3HB-co-4HB) relative to P(3HB) brittleness and toughness. The study also found that The 4HB content increased from 0 to 18 mol%, and the melting point decreased from 178 ° C to 150 ° C (Kunioka, Masao, Akira Tamaki and Yoshiharu Doi, crystallization and thermal properties of bacterial copolyester: poly-3-hydroxybutyrate - 3-Hydroxyvalerate copolymer and poly-3-hydroxybutyrate-4-hydroxybutyrate copolymer ("Crystalline and Thermal Properties Of Bacterial copolyesters: Poly(3-hydroxybutyrate-co-3-hydroxvalerate) and Poly(3-hydroxybutyrate-co-4-hydroxybutyrate),") Macromolecules, 1988, No. 22, pp. 694-697. It was found that when 4HB units were present in P(3HB-co-4HB), the rate of biodegradation increased (Kunioka, Masao, Yasushi Kawaguchi and Yoshiharu) Doi, a bacterium that produces 3-hydroxybutyrate and 4-hydroxybutyrate biodegradable copolyester ("Production of Biodegradable copolyesters of 3-hydroxybutyrate and 4-hydroxybutyrate by Alcaligenes eutropus,") Technology (Appl. Microbiol Biotechnol) 1989, No. 30, pp. 569-573). In another study, the enzymatic degradation of the P(3HB-co-4HB) film was carried out in a phosphate buffer of 0.1 M extracellular depolymerase (purified from M. faecalis) at 37 ° C. The 4HB content increased, the enzyme degradation rate increased significantly, and the highest rate was 28 mol% at 4HB (Nakamura, Shigeo and Yoshiharu Doi, microbial synthesis of poly-3-hydroxybutyrate-4-hydroxybutyrate copolymer and ("Microbial Synthesis and Characterization of Poly(3-hydroxybutyrate-co-4-hydroxybutyrate),") Macromolecules, 1992, 85, No. 17, 4237-4241).

This may be due to a decrease in the crystallinity of the synthesized product; however, the presence of 4HB in the copolyester of more than 85 mol% inhibits enzymatic degradation (Kumaai, Y. Kanesawa and Y. Doi, Polymer Chemistry (Makromol. Chem), 1992). No. 193, p. 53, through Nakamura, Shigeo and Yoshiharu Doi, Microbial Synthesis and Properties of Poly-3-Hydroxybutyrate-4-Hydroxybutyrate Copolymers, Macromolecules, 1992, 85, No. 17, 4237- 4241 pages). In the comparison of the degradation rates of P(3HB-co-9% 4HB), P(3HB) and (HB-co-50% 3HV) films, P(3HB-co-9% 4HB) was found to be activated. The sludge was completely degraded within 2 weeks, and 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) film (Kunioka, Masao, Yasushi Kawaguchi and Yoshiharu Doi), producing hydroxybutyrate and 4-hydroxybutyrate Ester biodegradable copolyester application microbial technology 1989, No. 30, pp. 569-573).

The technical problem to be solved by the present invention is to provide a biodegradable material which has a prolonged shelf life in a clean environment and accelerates degradation in a dirty environment in view of the above-mentioned defects of slow degradation rate of the existing biodegradable materials.

The technical solution adopted by the present invention to solve the technical problem thereof is to construct a living creature Degradable materials, including PHAs and PLA, wherein the percentage of PLA is from 1% to 95%. In the biodegradable material of the present invention, the quality of the PLA is 100% to 50%.

In the biodegradable material of the present invention, the biodegradable material comprises PLA and PHB, wherein the PLA has a quality percentage of 75% to 85%, and the PHB has a quality percentage of 15% to 25%. %.

In the biodegradable material of the present invention, the PHAs are PHBs or PHVs, or copolymers or blends of PHBs and PHVs.

In the biodegradable material of the present invention, the PHBs are P(3HB-co-4HB) polymerized from 3HB and 4HB.

In the biodegradable material of the present invention, the molar percentage of the 4HB is from 5% to 85%.

In the biodegradable material of the present invention, the biodegradable material further includes cellulose fibers.

In the biodegradable material of the present invention, the biodegradable material is produced by thermoforming, injection molding or melt spinning to produce a film, a solid and a liquid container, a rigid or flexible package, a filamentous and a short fiber. Woven, knitted and non-woven fabrics, as well as composite products of fabrics and films.

In the biodegradable material of the present invention, the melt spinning comprises a spunbond and melt blown nonwoven treatment.

In the biodegradable material of the present invention, the non-woven fabric is bonded by wet bonding or dry bonding.

In the biodegradable material of the present invention, the non-woven fabric is needled Process, spunlace process, hot calendering, hot gas deposition or the following heat treatment: microwave, ultrasonic, welding, far infrared and near infrared heating.

In the biodegradable material of the present invention, the composite product is a rolled film or fabric, and is combined with a spin deposition treatment, a needle punching treatment, a stream deposition treatment of pulp or fibers, or a hydroentangling treatment.

In the biodegradable material of the present invention, the rolling comprises thermospun-meltblown-spunbond, or ultrasonic-bonded nonwoven, which is used in industrial and medical protective fabrics.

In the biodegradable material of the present invention, the composite product includes a thermospin-meltblown-spunbond, or an ultrasonic bonded nonwoven fabric, which is used as a spreader, a seat or a stretcher for a patient.

In the biodegradable material of the present invention, the composite product comprises a meltblown filter media by spunbonding as an inner and outer surface, the product being sewn or thermally bonded or ultrasonically pasted to the meltblown filter media.

In the biodegradable material of the present invention, the biodegradable material is made into a biodegradable film or a woven or knitted or non-woven fabric having reinforcing properties, and there are many disordered deposition of fibers due to these nonwoven fabrics. It has a low but controllable porosity, which allows rainwater and dew to penetrate freely from the soil and plants into the pores to increase biodegradation, thereby inhibiting weed growth and maintaining soil moisture.

The implementation of the biodegradable material of the present invention has the following beneficial effects: The present invention relates to a novel blend of PHAs and PLA polymers for use in the preparation of blended products of PHAs and PLAs which are capable of accelerating biodegradation in environments containing microorganisms. The new product can be used to produce film, solid and liquid containers, rigid or flexible by thermoforming, injection molding or melt spinning. Woven, knitted and non-woven fabrics of filamentous and staple fibers, as well as composite products of fabrics, films and other materials. These blends also extend the shelf life in a clean environment.

Although poly-3-hydroxybutyric acid and poly-4-hydroxybutyric acid polyester (P(3HB-co-4HB)) products are easily degraded in soil, sludge and seawater, degradation rate in water lacking microorganisms Very slow (Saito, Yuji, Shigeo Nakamura, Masaya Hiramitsu and Yoshiharu Doi, "Microbial Synthesis and Properties of Poly(3-Hydroxybutyrate-4-Hydroxybutyrate)", International Polymers 39 (1996), 169- 174). Therefore, P(3HB-co-4HB) products have a very long shelf life in a clean environment, such as dry storage in sealed packages or in wet wipes. However, when in a dirty environment containing microorganisms (such as soil, river water, river mud, manure humus, sludge, and seawater), the treated P (3HB-co-4HB) is treated with P (28.56-co-hydroxyl) Butyrate) fabrics, films and packaging materials are very susceptible to degradation. It should be noted that polylactic acid (PLA) is not easily degraded in the above-mentioned dirty environment, but is easily corroded. The heat and moisture in the humus first breaks down the PLA polymer into shorter polymer chains and eventually degrades into lactic acid. The humus and microorganisms in the soil then consume small polymer fragments and lactic acid as nutrients.

Therefore, mixing hydroxybutyrate with PLA will accelerate the degradation rate of the PHAs-PLA mixed product, such as P(3HB-co-4HB). In addition, by mixing PHAs and PLAs, the shelf life of products in a clean environment will be extended. Although the price of PLA has fallen sharply in the past 10 years, only slightly higher than synthetic polymers (such as polypropylene and PET polyester), but the price of PHAs is still It is 2 to 3 times higher than the PLA price. This is because PLA can be made by large-scale synthesis of lactic acid, which is produced by bacteria in combination with a specific carbon source and must be extracted from bacteria by solvent. Therefore, if more than 25% of PHA is mixed in PLA to melt-extrude products (such as woven and knitted fibers, nonwovens, films, food packaging containers, etc.), it will not be suitable for commercial applications.

The formulations of the four sets of sample solutions are listed in Tables 1, 2, 3 and 4, respectively. These samples are 400Kg, which are: wet wipes cleaning liquid (usually liquid in baby wipes packaging), water with some river mud collected from Dongjiang, Dongguan, China, river mud collected from Dongjiang, Dongguan, China. And the mixed humus produced by the sludge/sand/and cow dung, the above raw materials are mixed and diluted with distilled water, and the pH is adjusted to be greater than 7 by potassium hydroxide. Wherein, each treatment process uses two sample liquids of the same formulation, and each treatment box containing the sample to be treated is covered with a lid, and the pH value and the percentage of solids are detected every 2 weeks. The average results of the samples processed in the first 4 weeks are shown in Table 5.

In one embodiment of the invention, 25 Kg of 85% PLA (2002D from NatureWorks) and 15% PHB (3HB-co-4HB) blend, and 25 Kg of 75% PLA (2002D from NatureWorks) Blended with 25% PHB (3HB-co-4HB) blend and extruded into pellets, and shipped to Biax-Fiberflilm, Greenville, Wisconsin, USA, and then melt-spun to produce meltblown (meltblown, MB The fabric has a basis weight of 50 g/m2. For comparative testing, a 100% PLA (2002D produced by NatureWorks) MB fabric was also produced. During the melt-blown process of these polymers, it has become increasingly apparent that the temperature of the molten and hot gases used to prepare the MB fabric is too high because the 2002D PLA polymer has a very low melt index (indicating that the PLA has a very high Molecular weight), and a high temperature is required to increase the fluidity of the MN PLA so that it can be smoothly extruded from the meltblown die orifice. 100% 2002D PLA has a melting temperature of 274 ° C and a hot gas flow temperature of 576 ° C. In comparison, the melting coefficient is 70-80. Melt-spinning viscous PLA generally uses a melting temperature of 266 ° C and a hot gas flow temperature of 260 ° C (Wadsworth, Larry and Doug Brown, "High Strength, High Quality Meltblown Insulation, Filters and Wipes with Less Energy," published in Guangdong Nonwovens Association Conference, Guangdong, China, November 26-27, 2009). Therefore, due to the above two mixtures, the PHB component contained is markedly thermally degraded, as evidenced by the large amount of smoke in the extruded MB fibers and the low strength of the MB PLA/PHB fabric produced. Subsequent experiments envisage the use of a PLA polymer (PLA 6251D manufactured by NatureWorks) having a higher melt index (MI of 70-85, which requires a much lower MB treatment temperature) mixed with PHB in the same ratio. In addition, it is expected that the 6251D PLA will be produced on the 1 meter spunbond nonwoven test line with the same composition, typically operating at temperatures slightly above the melting point of the PLA and mixed PLA-PHB polymers, resulting in less thermal degradation. This is because it uses the filament drawing step in the SB process, which is not included in the MB process, so the filaments produced are significantly larger than the MB filaments produced using the same polymer, although the average fiber in the SB fabric The diameter is usually 12-25 μm, but in comparison to MB fabric it is 2-8 um. The second MB operation and SB operation of these polymer components will minimize thermal degradation effects such that the degradation observed during the biodegradation process is primarily due to biodegradation. In addition, due to the large difference in fiber diameter between MB and SB nonwoven fabrics, smaller MB fibers will have a larger surface area, making it easier and more biodegradable.

MB 100%2002D MB fabric, 85% 2002D PLA/15% PHB and 75% 2002D/25% PLA were rolled into a 12.5 inch wide 50 g/m2 weight and shipped from Biax-Fiberfilm to the Meiya Nonwovens Industry Limited US Pacific Nonwovens Industry Limited is located in No. 2 Dongdi Road, Qiantang Industrial Zone, Dongcheng District, Dongguan City, Guangdong Province, China. US Pacific Nonwovens & Technical Textile Technology (DongGuan) Limited). Among them, each fabric was selected to be 1.5 meters in different treatment methods, and then it was exposed to different treatment liquids together with samples to be removed from each treatment tank, and at 4 weeks, 8 weeks, 12 weeks, 16 Weekly and 20 weeks for corresponding repetitive processing

The test procedure was as follows. First, a wet wipe cleaning solution was added to the MB PLA and PLA-PHB fabrics, and stored in a perforated steel basket, exposed to a treatment tank, and the humus was gently washed in nylon stockings after four weeks of treatment. The MB sample in the medium was observed to be degraded by washing and drying. Add water to the MB fabric in the same manner as the wipes cleaning solution, and place it on the perforated steel basket in the lid-top processing box, removing 100% MB from all the treatment tanks every 4 weeks until 20 weeks. PLA, 85% PLA-15% PHB, and 75% PLA-25% PHB. First, the fabric exposed to river mud and sludge/sand/fat humus is placed in a treatment tank, and is immersed and completely infiltrated by the treatment liquid. The fabric is then placed in nylon pantyhose, half of the 1.5 meter sample is placed in one leg, the other half is added to the other leg, and the sock is gently stretched in the sample, followed by the sock containing the fabric. Buried into a suitable box containing river mud or humus, and each sock is attached with a label on the outside of the processing box through a nylon thread. The removed fabric sample was placed into a metal box with a screen at the bottom every 4 weeks, and the nylon knit fabric was placed on a sieve, and the treated fabric was gently washed by applying a low pressure spray directly on the palm. The second nylon knit fabric was then placed on the cleaned sample and gently flipped over to the other side for cleaning. All the treated fabrics were then placed on a laundry drying station for more than two days until they were dried before being sent to the laboratory for testing. A portion of each dried sample after processing is sent to an external laboratory for the degree of fiber damage detected by scanning electron microscopy as an experimental result in the process, and additionally by gel permeation chromatography to detect different Whether the molecular weight of the polymer changes and its approximate loss in the case of treatment, a differential thermal analysis can be performed to detect any change in the crystal phase.

After 4 weeks of different treatments, the physical property test results of the fabric are shown in the table, where Table 6A is 100% 2002D PLA MB fabric, Table 7A is 85% 2002D PLA/15% PHB MB sample, and Table 8A is 75% 2002D. /25% PHB fabric. The 100% MB PLA sample lost 6% of machine direction (MD) tensile strength after 4 weeks of exposure to the wipes cleaning solution, while 85% PLA / 15% PHB and 75% PLA / PHB The fabric lost only 4% and 1% of the mechanically oriented tensile strength in the wipes cleaning solution, respectively. However, 100% PLA, 85% PLA/15% PHB, and 75% PLA/25% PHB lost 50%, 32%, and 65% of cross machine direction (CD) Trapezoid tearing strength, respectively. ). After 4 weeks in river water, 100% MB PLA lost 26% MD tensile strength and 64% CD tear strength, while 85% PLA/15% PHB and 75% PLA/25% PHB lost 19% and 22 respectively. % MD tensile strength, and 77% and 80% CD tear strength. After 4 weeks in the river mud, 100% PLA fabric lost 91% MD tensile strength and 98% CD tear strength, while 85% PLA/15% and 75% PLA/25% PHB lost 76% and 75%, respectively. MD tensile strength, and 96% and 87% CD tear strength. After 4 weeks in sludge/sand/bovine manure humus, 100% PLA fabric lost 94% MD tensile strength and 99% CD tear strength, while 85% PLA/15% and 75% PLA/25% PHB 76% and 86% MD tensile strength, and 99% and 83% CD tear strength were lost, respectively. All samples exposed to river mud and humus have enhanced gas permeability, which has a higher gas permeability value, indicating that more open structures are produced as biodegradation increases. The gas permeability of the various treated MB 100% PLA fabrics was less than that of the PLA-PHB hybrid fabric. No fabric loses weight, but there is actually some increase because it is difficult to remove all of the treated debris without causing deeper damage to the fabric.

Table 1. Formulation of wet wipes cleaning solution loaded in two different boxes

Table 3. River mud components loaded in two boxes

Description of Table 4: 69 Kg of dry sludge (USP gardener is taken from the river) is added to the large mixing vessel; 69 Kg of dried cow dung has been added, which has been broken into small pieces by slow stirring with a large electric mixer; 69 Kg of dry sand is slowly added during mixing. Slowly add 83Kg distilled water while stirring; after complete mixing, check the pH value with litmus paper or pH meter, slowly add 10% sodium hydroxide (prepared with distilled water) until the pH reaches 7.5; The remaining distilled water was added to bring the water in the added calcium hydroxide to a total amount of 93 Kg, and the pH was checked and adjusted to 7.5.

Table 7A. Weight, thickness, gas permeability and strength characteristics of 85% PLA (2002D)/15% PHB after production and after 4 weeks of exposure to cleaning fluids, river water, river mud and sludge/sand/fat humus

It is known to those skilled in the art that, in addition to P(3HB-co-4HB) polymerized from 3HB and 4HB, the PHAs contained in the biodegradable material in the present application may be PHBs. Or PHVs, or copolymers or blends of PHBs and PHVs.

Those skilled in the art will appreciate that the biodegradable materials of the present application can be produced by thermoforming, injection molding or melt spinning to produce film, solid and liquid containers, rigid or flexible packages, filamentous and staple fibers. Woven, knitted and non-woven fabrics, as well as composite products of fabrics and films. In a preferred embodiment of the invention, the melt spinning comprises a spunbond and meltblown nonwoven treatment. In another preferred embodiment of the invention, the nonwoven fabric is bonded by wet bonding or dry bonding. In still another preferred embodiment of the present invention, the nonwoven fabric is obtained by a needling process, a hydroentanglement process, hot calendering, hot air deposition or the following heat treatment: microwave, ultrasonic, welding, far infrared and near infrared heating.

It is further known to those skilled in the art that the composite product of the above fabric and film is a rolled film or fabric combined with a spin deposition process, a needling process, a stream deposition process of pulp or fibers, or a hydroentanglement process. Wherein, the rolling comprises thermospinning-meltblown-spinning, or ultrasonic bonding non-woven treatment. The composite product is used in industrial and medical protective fabrics. For example, the composite product includes a thermospun-meltblown-spunbond, or an ultrasonic bonded nonwoven, used as a spreader, seat or stretcher for a patient. In addition, the composite product includes a meltblown filter media that is spunbonded as an inner and outer surface that is sewn or thermally bonded or ultrasonically pasted to the meltblown filter media.

Those skilled in the art can fully accomplish the above operations in accordance with the teachings of the present invention in conjunction with the prior art, and will not be described herein. While the invention has been described by way of specific embodiments, the embodiments of the invention because Therefore, the invention is not limited to the specific embodiments disclosed, but all the embodiments falling within the scope of the appended claims.

Claims (16)

A biodegradable material, including PHAs and PLA, wherein the percentage of PLA is from 1% to 95%. The biodegradable material according to claim 1, wherein the PLA has a quality percentage content of 10% to 50%. The biodegradable material according to claim 2, wherein the biodegradable material comprises PLA and PHB, wherein the PLA has a quality percentage of 75% to 85%, and the PHB has a quality percentage of 15%. % to 25%. The biodegradable material according to claim 1, wherein the PHAs are PHBs or PHVs, or copolymers or blends of PHBs and PHVs. The biodegradable material according to claim 4, wherein the PHBs are P(3HB-co-4HB) polymerized from 3HB and 4HB. The biodegradable material according to claim 5, characterized in that the molar percentage of the 4HB is from 5% to 85%. The biodegradable material according to claim 1, wherein the biodegradable material further comprises cellulose fibers. The biodegradable material according to claim 1, wherein the biodegradable material is produced by thermoforming, injection molding or melt spinning to produce a film, a solid and a liquid container, a rigid or flexible package, and a filamentous shape. And woven, knitted and non-woven fabrics of short fibers, as well as composite products of fabrics and films. The biodegradable material of claim 8, wherein the melt spinning comprises a spunbond and meltblown nonwoven treatment. The biodegradable material according to claim 9, wherein the non-woven fabric is bonded by wet bonding or dry bonding. The biodegradable material according to claim 9, wherein the non-woven fabric is obtained by a needling process, a hydroentanglement process, hot calendering, hot air deposition or the following heat treatment: microwave, ultrasonic, welding, Far infrared and near infrared heating. The biodegradable material according to claim 7, characterized in that the composite product is a laminated film or fabric combined with a spinning deposition treatment, a needle-punching treatment, a flow deposition treatment of pulp or fibers, or water. Thorn treatment. The biodegradable material according to claim 12, characterized in that the rolling comprises thermospinning-meltblown-spunbonding or ultrasonic bonding non-woven treatment, the composite product being used for industrial and medical protective fabrics. . The biodegradable material according to claim 12, characterized in that the composite product comprises a thermospin-meltblown-spunbond or a ultrasonic bonded nonwoven fabric used as a spreader, a seat or a stretcher for a patient. . The biodegradable material according to claim 11, wherein the composite product comprises a meltblown filter medium by spunbonding as an inner and outer surface, the product being sewn or thermally bonded at the edge or ultrasonically pasted by the meltblown filter. medium. The biodegradable material according to claim 1, characterized in that the biodegradable material is made into a biodegradable film or a woven or knitted or non-woven fabric having reinforcing properties, since many fibers are present in these non-woven fabrics. The disordered deposition and low but controlled porosity allow rainwater and dew to penetrate freely from the soil and plants into the pores to increase biodegradation, thereby inhibiting weed growth and maintaining soil moisture.