JP2011510106A - Inorganic particle additives surface treated to increase polymer toughness - Google Patents

Abstract

The bioplastic composition includes a biopolymer comprising 10% to 40% by weight of coated inorganic particles. The particles are coated with one or more of fatty acids, fatty acid derivatives, rosins, rosinates, polyolefin waxes, oligomers and mineral oils, and combinations thereof. Thereby, the rigidity and toughness were improved and the crystallization rate was improved. It is useful for extrusion, injection molding, and thermoforming.

Description

  The present invention relates to improvements in or related to the composition of polymers (compositions, compositions, formulations). In particular, the present invention is a bioplastic system comprising a biopolymer (biopolymer, biopolymer) material (substance), wherein the biopolymer material is biodegradable and / or Or it relates to a bioplastic system that is derived from renewable resources and has sufficiently improved strength.

  The improved strength is manifested by a combination of stiffness and toughness. In one embodiment, the improved strength allows the polymer to be processed as a film and used in economically attractive thin thicknesses. It (improved strength) also makes it possible to manufacture or produce thermoformed articles, such as food trays, from thin materials. Plastic films have numerous applications, and the economics of film manufacture and use are often governed by the film thickness required to impart certain mechanical properties. (Affected by it) The thinner the film that gives the desired properties, the better. In addition, the present invention can improve the crystallization kinetics of biopolymers, for example, extrusion molding, injection molding and blow. The polymer processability in technologies such as molding can be improved.

  Plastic processing (disposal, disposal) is an increasing concern, and biodegradablity is important in reducing the amount of non-disposable plastic waste. Biodegradability can take a variety of forms, for example, in the form of films produced from naturally biodegradable polymers, possibly compostable with the aid of chemicals. Natural biodegradability can occur when a film, such as an agricultural mulching film, is embedded in the soil after use. Various polymers have been developed for biodegradability. However, these polymers tend to have low mechanical strength that is unsuitable for certain applications, or, for example, thick thicknesses that are undesirable for processing and winding without causing fractures. Tend to have a low mechanical strength that requires the film. Impact resistance, tear resistance and mode of failure are all the same for films, thermoformed parts and injection molded parts. It is an important characteristic. In particular, the biodegradable polymers associated with the present invention tend to be brittle due to the inherent low toughness expressed as the ability to absorb energy prior to failure. This brittleness causes fracture and splintering when subjected to impacts that can cause polymer fragments from packaging materials in products such as food, for example. It can be a cause. In one embodiment of the present invention, a bioplastic having a ductile failure mechanism useful as a film for thermoforming and injection molding applications is realized.

  Examples of biopolymers relevant to the present invention are polylactic acid, polyglyconate, sometimes known as polylactide (PLA), polyglyconate, poly (dioxanone) (poly). (dioxanone)), polyhydroxy alkanoates (polyhydroxyalkanoates, polyhydroxyalkanoates) (PHA), especially polyhydroxybutyrates (polyhydroxybutyrates), polyhydroxy Polyhydroxy vatarates, polymeric thermoplastic starches (amylose levels higher than 60%) and / or combinations thereof, these Collectively It is known as biopolymers (biopolymer). Polylactides have been proposed as biodegradable alternatives to polypropylene and polystyrene, but do not have sufficient strength. According to the present invention, such a sufficient strength can be imparted to polylactide, and competitiveness can be imparted to polylactide as a biodegradable alternative to polycarbonates (polycarbonates).

  These polymers, particularly amorphous PLA, have a low heat deflection temperature (HDT), which limits their use to high temperature applications (applications). Furthermore, they (polymers) may have slow crystallisation kinetics that require long molding cycle times (periods), particularly in injection molding.

  Accordingly, it is an object of the present invention to increase the strength of bioplastics, shorten the molding cycle time, and improve the crystallization reaction rate (kinetics) without substantially reducing biodegradability. . Previously it was proposed to improve the toughness of rubber by including it in polylactide. However, although the toughness of polylactide has been improved, the stiffness of polylactide is reduced and normal rubber is not biodegradable. Recently available biodegradable rubber is quite expensive.

  It is well known to include fillers (fillers, fillers) in polymeric materials for various reasons. Fillers are generally included (added) to provide strength and / or to lower the cost of articles formed of polymeric materials. The filler may be included (added) in molding (molding, molding) and extrusion (molding) of all shapes and sizes (sizes, dimensions). Calcium carbonate is well known as a filler for polymers, tailoring the size and morphology of calcium carbonate and adding it (calcium carbonate, filler). It is known that certain desired properties can be imparted to the polymer. For example, it has been proposed in British Patent Publication GB 2336366A that calcium carbonate may be included in polyethylene, and US Pat. No. 6,911,522 similarly includes calcium carbonate in ε-caprolactone polymers. It is described. Zhiyong Xia, Dennis, Prendes, Patrick Wernett, “The Reinforcement of Poly (Lactic Acid) using High Aspect Ratio Calcium Carbonate based Mineral Additive” (high aspect ratio ( Poly (lactic acid) reinforcement with mineral additives (based on the base), based on calcium carbonate with a flattening ratio), in order to improve toughness (toughness) and stiffness, M Force, a calcium carbonate additive. Inclusion of bio (EMforce® Bio) is described.

  It is also known that calcium carbonate may be coated to improve compatibility with the polymer in which it is used. For example, in GB2336366A, polyethylene is filled with calcium carbonate coated with stearic acid to avoid die lip build up when the polymer is extruded. U.S. Pat. No. 6,815,479 discloses 2.50 to 4.00% by weight as a filler for polymer Capron nylon to improve the impact strength of the polymer. The use of calcium carbonate coated with stearic acid is described.

British Patent Publication GB2336366A US Pat. No. 6,911,522 US Pat. No. 6,815,479

  The use of certain fillers in bioplastics can increase their strength without compromising the biodegradability of the bioplastic, in particular impact resistance and ductability without compromising the polymer's stiffness. I discovered that. Ductility is indicated by the shape of the stress-strain curve, and the area (region) under the curve up to the maximum peak (on the break side) is below the stress-strain curve. If the area is greater than 35% of the total area (generally considered to have a ductile failure mode), it is indicated by an indication that the bioplastic is ductile. This is particularly useful when producing films using the biopolymer containing the filler, as it allows the production of thinner films having the desired mechanical properties without compromising biodegradability, I found It is particularly useful in the manufacture of refuse sacks and agricultural films that can be embedded in soil after use and composted. It is also useful in thermoforming and injection molding applications (applications) where ductility and reduced brittleness reduce the bioplastic's splinter.

  Accordingly, one embodiment of the present invention provides a bioplastic that includes (contains) 10 to 40% by weight of a coated filler that is heated to 200 ° C. to provide a constant It contains less than 1% moisture when measured in a reduced weight state when it reaches weight.

  In another embodiment of the invention, about 2.3% or more by weight of fatty acid, fatty acid derivative, rosin, rosinate, polyolefin-based A bioplastic comprising 10 to 40% by weight of inorganic particles coated with a (based on) wax, oligomer, and / or mineral oil (oil), and / or combinations thereof .

  In another embodiment of the invention, in order to improve the impact resistance of bioplastics without sacrificing the stiffness of the bioplastics, fatty acids, fatty acid derivatives, rosins, rosinates, polyolefin based Inorganic particles coated with one or more of (based on) waxes, oligomers, and mineral oils (oils) are used.

  In another embodiment of the present invention, a fatty acid, a fatty acid derivative, a rosin, a rosinate, a polyolefin-based (based on the base material) is used to accelerate the crystallization reaction rate (dynamics) of the biopolymer from the melt ) Use inorganic particles coated with one or more of waxes, oligomers, and mineral oils.

The combination of coating on the filler and low moisture content is important to enable the production of high strength biodegradable materials and to accelerate crystallization from the melt (state), discovered. One function of the coating is to act as a dispersant. It is preferably a molecule with a polar head attached to the filler particles so that it cannot be covered by the biopolymer when in the molten state. It also preferably has a substantially non polar tail that integrates with the polymer structure to aid dispersion of the filler within the polymer. Examples of suitable dispersants are fatty acids and derivatives thereof (eg fatty acid amides and fatty acid esters), and alkali metal salts thereof. For _example, saturated and unsaturated carboxylic acids (Carboxylic Acids) and alkali metal salts of C 10 _{-C 22,} for example, stearic acid (Stearic acid), palmitic acid (palmitic acid), myristic acid (myristic acid), oleic acid ( oleic acid, linoleic acid, linolenic acid, and their sodium salts are particularly useful. Rosin, rosinate, and abietic acid based (abetic acid based) materials are other suitable materials that may be used. Other next preferred coating materials that can be used include polyolefin-based waxes, oligomers and mineral oils, and combinations thereof.

  It has been discovered that the amount of coating used is important in obtaining improved bioplastic properties. The amount required depends on (depends on) the nature of the biopolymer and the particular property or properties of interest of the bioplastic user. When the inventor uses polylactides, it is preferred that the coating be present in an amount of filler material in an amount of at least 2.3 wt%, even if an amount of filler material up to 10.0 wt% is used. I found a good thing. L-polylactide can typically be up to about 40% by weight crystalline material with the remainder (remaining weight%) being amorphous (material). The coated filler used in the present invention is believed (believed) to provide two functions, particularly in polylactic acid. First, it (filler) is the crystallization nucleus of the polymer, increasing the crystallization rate (rate) and producing more uniform crystals. Secondly, it (the filler) peels from the amorphous phase of the polymer (amorphous phase polymer) when impacted, thus absorbing energy and propagating (spreading) cracks. Reduces the brittleness of the polymer while increasing the strength of the material. If the polymer is poly-3-hydroxy butyrate with high crystallinity, a smaller amount of dispersant may be required.

  A preferred filler is calcium carbonate, which may be precipitated calcium carbonate (PCC) or ground calcium carbonate (GCC). Precipitated calcium carbonate is preferred, and the calcium carbonate is acicular and has an aspect ratio (length: width, length to width) greater than 4, preferably greater than 5. The aspect ratio of heavy calcium carbonate (GCC) is typically about 1. The aspect ratio of the filler particles was determined (determined) using an injection molded polymer-metal composite piece. The polymer was plasma etched to expose the mineral particles, which were removed from the surface using 2-propanol. The collected mineral particles were analyzed by transmission electron microscopy (TEM) using a JOEL LTD. JEM 1200 EXII instrument. Digital images were collected using the Advanced Microscopy Techniques, Incorporated digital camera system, and the filler dimensions were measured using ImagePro Plus® software. It was. For each sample (specimen), 24 TEM images were collected and analyzed. The average aspect ratio value was then derived by a curve that fits the ratio of the long dimension to the short dimension (long dimension vs. short dimension) of the particle (aspect ratio) distribution data.

  The calcium carbonate, whether PCC or GCC, preferably has a 95% particle size (particle size) as measured by a Micrometrics 5001 Cedigraph. In particular, 90% of all particles have a size of 20 microns or less (only 20 microns), more preferably 18 microns or less (only 18 microns), most preferably 2 microns or less (only 2 Preferably having a size of micron). The particle size was measured using 2 g of uncoated calcium carbonate in 50 ml of 0.2% DAXAD solution for only 5 minutes prior to introduction into the sedigraph instrument. With a power setting of .5, the slurry is sonicated with ultrasound and executed.

  The moisture content of the filler is 1% by weight or less (about 1% by weight) based on (based on) the weight of the filler, more preferably the water content is 0.5 at the treatment temperature of the biopolymer. It is important that it is less than% by weight. Its moisture content is measured by Karl Fischer titration of the sample when heated to 200 ° C. The biopolymers according to the present invention are biodegradable, can be composted and tend to degrade in the presence of moisture, and the degradation accelerates (accelerates) at the high temperatures typically used to process biopolymers. ) For example, polylactic acid is typically treated at temperatures in the range of 180 ° C. to 210 ° C., and the presence of water can cause fast biodegradation of the polymer at these temperatures.

Thus, according to a preferred embodiment of the present invention, for example by means of inorganic additives (additives) such as, for example, calcium carbonate (CaCO ₃ ) particles coated with fatty acids, the toughness (toughness) of the polymer and for example biodegradation Mechanical properties such as the toughness (toughness) of biopolymers such as biolactide (PLA) polymers that can be made or composted are improved without impeding the compostablity of the polymer. Toughness is the ability of a material to absorb energy during fracture, for example biodegradable polymers such as PLA are brittle due to their inherent low toughness. Although this property of the biopolymer has limited its use, its toughness of the biopolymer is substantially or sufficiently (significantly) improved when enhanced with inorganic additives in accordance with the present disclosure. And the usefulness of the biopolymer is enhanced. Inorganic additives coated with fatty acids, such as calcium carbonate coated with fatty acids, can be used to enhance the toughness or impact resistance of the biopolymer. Such biopolymers are, for example, PLA, polyglyconate, poly (dioxanone), polyhydroxyalkanoates (PHA), in particular polyhydroxybutyrate. (Polyhydroxbutyrates), and / or thermoplastic polymer (polymer) starch (eg containing more than 60% amylose), and / or combinations thereof.

  What is referred to herein as a biopolymer includes a polymer derived from a natural renewable resource and / or a polymer that is generally compostable or generally biodegradable. It is. Bioplastic materials contain those biopolymers. According to the invention, the improvement (improvement) of the toughness of the bioplastic is effected by incorporating an additive comprising inorganic particles coated with a coating material. The coating material is, for example, one of fatty acids, fatty acid derivatives (eg fatty acid amides and fatty acid esters), rosins, rosinates, oligomers, polyolefin-based (based on) waxes, and mineral oils. It ’s like that. The inorganic particles are preferably coated with a coating material at a coating level of about 2.3% by weight or more per weight of the inorganic particles. Bioplastics according to the present invention have improved physical properties (including toughness, ductility and / or stiffness) and may be incorporated into various products. Its various products include automotive, electronics, appliance components (eg, bumpers, dashboards, computer / mobile (portable) phone housings (housings), Etc.), consumer goods (consumer goods) (eg, credit card materials (stock), eating utensils, cups, food trays, fast food containers (containers, containers), plateware, etc.) And packaged products (eg, food containers (containers, containers), bottles (bottles), films such as agricultural films, refuse sacks, etc.).

  It has also been found by the present invention that the crystallization reaction rate (kinetics) of the biopolymer is improved by incorporating the coated filler into the bioplastic. Faster crystallization makes it possible to shorten the molding cycle of processes (operations) such as injection molding and thermoforming, in particular the time required for the molding of PLA is considerably longer.

The filler is typically inorganic particles, carbonate, silica, kaolin, talc, fine metal particles, wollastonite, and / or ) Glass microspheres (microspheres) and / or one (or one) of these combinations. According to one preferred embodiment, the inorganic particles are calcium carbonate particles coated with a C _{10 to} C ₂₂ fatty acid or derivative thereof at a coating level in the range of about 2.3 to 10% by weight of calcium carbonate. It is. The calcium carbonate can be any type of calcium carbonate, for example, precipitated calcium carbonate (PCC), heavy calcium carbonate (GCC), and / or mixtures thereof ( Blend).

  In one embodiment for enhancing the toughness of PLA polymer, the inorganic additive may be a particulate form of calcium carbonate additive material such as PCC, GCC or mixtures thereof. Some examples of calcium carbonate additives that can realize the disclosure herein are the Omyacarb UFT product available from OMYA Inc. North America, and Specialty Minerals Inc. Superfil (registered trademark) product commercially available from Specialty Minerals Inc. The calcium carbonate particles can be coated with a fatty acid such as stearic acid, for example. It (stearic acid) is one of the useful types of saturated fatty acids derived from many animal and vegetable fats and oils (oils).

  The above-described enhanced polymer preparation involves compounding the coated calcium carbonate particles into a polymer resin precursor for a bioplastic material and forming the composite into the desired shape (form). This can be done by forming the film. The coated calcium carbonate particles can be mixed into the polymer resin precursor by melt compounding using a twin screw extruder or similar device. An example of such an extruder is a twin screw extruder manufactured by Leistritz Corporation. Additives for enhancing the toughness of PLA polymers from about 2.3 wt%, and from about 2.3 wt% up to about 10.0 wt% (about 2.3 to about 10.0 wt%) Preferably up to about 6.0% by weight (about 2.3 to about 6.0% by weight), more preferably up to about 4.0% by weight (about 2.3 to about 4.0% by weight) fatty acids. Can be mixed into the PLA at a loading level of 15-30% by weight of the PLA polymer.

  Coating mineral particles according to the methods disclosed herein resulted in an unexpected significant increase in the toughness of the bioplastic system. In general, the surface treatment of mineral filler particles in a polymer system generally improves the mechanical properties of the polymer somewhat by reducing the absorbed moisture in the particles and lowering the surface energy of the mineral particles. Are known. The result is a good dispersion of the mineral particles in the polymer system. However, it has been observed that the use of previously known surface treatments on mineral filler particles only slightly increases the toughness of the polymer system.

  By coating the mineral particles according to the methods disclosed herein, a substantial (significant) increase in the toughness of the bioplastic composite is achieved. The result is that the coated mineral particles in the resulting polymer composite matrix (matrix) are more efficient for the particles and polymers compared to the normal surface treated mineral fillers in other polymer systems. It seems to be due to (cause) energy absorption by peeling at the interface (interface peeling). Delamination at the interface between the particles and the biopolymer absorbs the energy of the cracks that propagate through the polymer composite. This is believed to be the case, particularly in the case of using a polymer such as PLA containing a sufficient amount of amorphous regions, for example.

  Bioplastics containing the coated filler may be processed to produce a wide range of articles conventionally formed of plastic. They may be injection molded, extruded, thermoformed or blow molded depending on the nature of the article being manufactured. In injection molding, the composition preferably comprises 10 to 40% by weight coated filler, more preferably 15 to 30% by weight coated filler, in particular 20 to 30% by weight coated filler. . In extrusion, materials with up to 40% by weight coated filler should be used. The material may be used to produce molded components for the transportation industry, household goods, packaging materials, construction materials, and the like. One particular application is the production of films, especially those that can be composted and can be used as agricultural films and garbage bags. Here, the inventor has discovered that the use of the additive of the present invention allows the production of thin films having the desired mechanical properties. For example, an agricultural film that can be made into a polylactic acid compost may have a required (necessary) mechanical property. Its required mechanical properties are, for example, impact strength, tear resistance, and ductile failure of less than 50% thickness of comparable (equivalent) film without filler. In some cases, the required mechanical properties can be obtained even with a thickness of 30% or 25% of the thickness of a single unfilled (filler-free) film. is there. These films may be produced by a bubble expansion process or a stenter process. Alternatively, biodegradable food trays may be manufactured (formed) by thermoforming these polymers.

  In processing other polymer systems, it is usually necessary to include various additives in the polymer to aid processing. Examples are slip agents, antistatic agents, viscosity modifiers, and the like. Another advantage of the present invention is that the biopolymer according to the present invention may be processed without the need for any additional additives. Thus, in another embodiment of the present invention, the bioplastic composition of the present invention is substantially free of additional (other) additives.

  The invention will now be described with reference to the following example.

Example 1
In laboratory experiments, the inventors have been able to demonstrate (demonstrate) the beneficial effects of fatty acid coated calcium carbonate additives in improving the toughness of PLA polymers. In particular, improved impact toughness at room and low temperatures and improved PLA stiffness has been demonstrated (proven).

  The properties of the PLA polymer can be controlled by controlling (preparing) the ratio of stereoisomers containing PLA. For example, predominantly (major component, most) L-form (L-lactide) with greater than about 15 mole% of mole% (ratio) of either D-lactide or meso-lactide (either). ) To produce an amorphous PLA random (disordered) copolymer. On the other hand, polymerization of L-form lactic acid yields poly-L-lactide (PLLA), a semi-crystalline polymer having a degree of crystallinity of up to 40% or higher.

  The inventor uses a number of different calcium carbonate based (calcium carbonate based, calcium carbonate based) additives, which are coated with stearic acid and mixed into a sample of PLLA polymer Thus, the beneficial effect of calcium carbonate coated with stearic acid on the mechanical properties of PLA was confirmed. Samples of specific calcium carbonate additives used as starting materials are available from Specialty Minerals, Inc., EMforce® Bio, Superfil®, OMYA Inc. Omyacarb UFT), and Emforce Bio (Superforce® Bio) and Superfil® mixed in a 50:50 ratio. Specialty Minerals, Inc.'s EMforce (R) Bio is an engineered calcium carbonate filler additive coated with greater than 2.7% by weight fatty acid produced. , Intended to reinforce (reinforce) biopolymers. Other calcium carbonate additive samples were each coated to a coating level concentration (0.0 to 4.0 wt%) using a laboratory Henschel mixer. Each calcium carbonate additive was mixed into the PLLA resin at a target concentration of about 25% by weight level.

  Mixing of the calcium carbonate additive into PLLA can be performed by melt mixing using a twin screw extruder. In this example, all formulations were mixed using a Leistritz twin screw extruder having an L / D ratio of 40, a diameter of 27 mm, and 10 independent heating zones. The extruder was operated in a co-rotating mode to ensure good dispersion of calcium carbonate in PLLA. The PLLA resin is fed into the feed port of the extruder using a K-TRON (K-TRON) hopper-fed loss on weight feeder (weight detection type continuous feed feeder). Injected (at ambient temperature). All fillers were fed from the side (lateral direction) into zone 5 of the extruder via a K-Tron loss-on-weight feeder.

  EMforce (R) Bio material is manufactured at Specialty Minerals, Inc.'s manufacturing facility and has a coating level of 3.3% by weight and 0.5% by weight. Has a lower moisture content. Other calcium carbonate additive samples were prepared (prepared) in the laboratory to a total coating level of 3.3% by weight. EMforce® Bio formed the greatest impact / stiffness balance compared to other fillers, but at 3.3 wt% coverage level, all fillers (Omya UFT products) Increased the toughness of PLLA as well. Emforce Bio (Superforce® Bio) and Superfil® mixed in a 50:50 ratio form an intermediate property between the two pure components, This is a promising option for the “next generation” EMforce® Bio (EMforce® Bio) product as a potential low-cost product. When 3.3 wt% fatty acid was added to the PLLA resin without the calcium carbonate additive, the mechanical properties were not improved compared to the unfilled (no filler) resin.

  The calcium carbonate additive is melt mixed with PLLA (Natureworks 4042D) on a Leistritz 27 mm twin screw extruder operating in the same speed mode with target concentrations of 20, 25 and 30 wt%. It was done. In addition, 3.3% by weight of fatty acid was also mixed with PLLA, and it was determined whether the toughness of PLLA was improved only by the fatty acid. Prior to injection molding on an 88 ton all-rounder machine from Argburg, the composite samples were dusted with aluminum stearate antiblocking agent. Test specimens were prepared for 3 days in a controlled temperature and humidity environment (23 ° C., 50% RH (relative humidity)) for 3 days prior to mechanical testing.

  The particle size distribution of calcium carbonate used in this study is shown in Table 1 and plotted in FIG. The plotted samples are Superfil® calcium carbonate 11 coated with stearic acid at a 3.3 wt% level; UFT calcium carbonate 12 coated with stearic acid at a 3.3 wt% level. EMforce® Bio (Pallet # 12) 13 with a produced 3.3 wt% coating level; and 50/50 mixed EMforce® Bio (EMforce® Bio); ) / Superfil (registered trademark) 14. Superfil (R) 11 has the largest maximum size and median particle size, and EMforce (R) Bio 13 has the smallest maximum size and median particle. Had a size.

  FIG. 2 shows the flexural modulus of various polymer samples measured at 23 ° C. (room temperature). As described above, PLLA resin samples were mixed with calcium carbonate to target concentrations of 20, 25 and 30 wt%. Each line plot shown is PLLA21 filled with Superfil® (3.3 wt% coating level); PLLA 22 filled with UFT (3.3 wt% coating level); PLLA23 loaded with EMforce (R) Bio (3.3 wt% coating level); 50/50 mixed EMforce (R) Bio / Superfil (R) ) PLLA 24 filled with the mixture (3.3 wt% coating level). In addition, each reference reference (control) sample of PLLA 26 with an unfilled PLLA control (control) 25 and only 3.3 wt% stearic acid (based on the total weight of the polymer composite). Were prepared and measured. The two comparative reference samples are not filled with calcium carbonate, so their additive concentration level is 0.0 wt%. All calcium carbonate additives significantly (significantly) increased flexural modulus compared to unfilled PLLA 25 and stearic acid-PLLA resin mixture 26. PLLA23 filled with EMforce® Bio produced the greatest increase in flexural modulus. PLLA21 filled with Superfil (R) caused a minimal increase in the flexural modulus of all calcium carbonate containing composite materials. A 50/50 EMforce® Bio / Superfil® mixture 24 produced intermediate results as expected.

  FIG. 3 shows the result of Dynatup's multiaxial impact energy at 23 ° C. (room temperature). PLLA composite material 33 filled with EMforce® Bio formed maximum toughness at room temperature compared to PLLA composite materials 31 and 34 filled with other calcium carbonate. However, the case of PLLA 32 filled with 30% by weight of UFT having the same (comparable) toughness is excluded. In previous studies, to increase the toughness of PLLA composites substantially (sufficiently and significantly), a minimum of 20% by weight of Emforce Bio (EMforce®) compared to the unfilled comparative reference PLLA35. ) Bio) was shown to be necessary. Maximum toughness is achieved by filling approximately 25% by weight of EMforce® Bio, which toughness begins to decrease above 30% by weight. This same trend is observed for PLLA31 and Superforce® 34 filled with Superfil® and EMforce® Bio / Superfil® mixture 34.

  FIG. 4 shows the results of the Dynatup multi-axis impact energy at 0 ° C. All PLLA composites failed (failure) in brittle mode (or almost all brittle failure (failure), see Table 2). In this case, PLLA41 filled with Superfil (R) produced the greatest toughness, and PLLA42 filled with UFT matched it at 30 wt% concentration. This is believed to be due to the surface area coverage level effect of Superfil® having the smallest surface area. The smaller surface area of Superfil® products will require less stearic acid molecules to encapsulate particles compared to larger surface area particles. . This would be expected to form a thicker (darker) coating level around Superfil® particles. In previous work at NatureWorks 4032D PLLA, EMforce® Bio can greatly increase the impact energy of PLLA at 0 ° C., with a weight of about 3.5 wt% or greater. It has been shown that a ductile failure (failure) mechanism occurs at a coating level concentration of%.

  Further, the table 2 includes data of heat deflection temperature (heat deflection temperature: heat deflection temperature) (“HDT”). All mineral fillers at all concentrations tested in this study had no effect on increasing HDL of PLLA. The addition of stearic acid in the absence of mineral filler showed a significant (significant) decrease in PLLA DHT.

  FIG. 5 shows the results of a room temperature notched Izod impact test performed on a polymer sample. All PLLA composites loaded with stearic acid coated calcium carbonate were slightly better than the unfilled and stearic acid-PLLA comparative reference samples and were similar to each other. The plotted lines shown are: PLLA 51 filled with Superfil®, PLLA 52 filled with UFT, PLLA 53 loaded with EMforce® Bio, 50/50 mixed emforce. A PLLA 54 filled with a bio (EMforce® Bio) / Superfil® mixture, an unfilled PLLA comparative reference sample 55, and a PLLA comparative reference sample 56 with stearic acid.

  In the above experiment, at a coating level of 3.3% by weight, compared to the performance achieved with a coating level of 2.7% by weight, compared to the mechanical properties of PLLA, for example impact toughness. No further improvement is observed.

Example 2
FIG. 6 shows the results of a coating level study for uncoated EMforce® Bio carbonate calcium carbonate particles to determine the optimal coating level. The falling weight impact energy was measured for PLA samples prepared from polymer resin mixed with various coating levels of calcium carbonate particles. The calcium carbonate precursor samples were dry-coated using a laboratory Henschel mixer (mixer) for each coating level concentration (0.0 to 4.0 wt%). However, the coating process is not limited to the dry coating process. Wet (liquid) coating treatment can also be used. Each calcium carbonate material was mixed with PLLA with a target concentration of 25% by weight. The toughness measurement (value) in this test is the drop weight. The resulting plot of FIG. 6 shows a classic “S-shaped” curve 60 that demonstrates the minimum coating level required to improve the impact toughness of PLLA. From the steep portion 62 of the “S-curve”, the impact toughness of the PLLA composite material is greatly improved to about 25 ft.lbs. (About 3.5 mkg) or better. A minimum coating amount of about 2.3% by weight is estimated. Tables 3A to 3C show the basic data of the plot of FIG.

  Note: All samples were evaluated in a 2.3 kg (5 lb) batch (unit bundle) without annealing.

  According to the data described above, at room temperature, the transition between brittleness and ductility occurs at a level higher than a coating level of about 2.0% by weight. Falling weight failure (fracture) will remain ductile at all values above about 2.5% by weight, and the beneficial effect will be flattened somewhat above about 3.0% by weight in room temperature applications. It is. This transition point is most likely to change if the test conditions change. Thus, for at least room temperature applications, in PLA polymer systems, the coating level can be controlled within the range of about 2.3 to 4.0 weight percent to minimize the coverage. As shown in the curve of FIG. 6, the Dynatup drop energy begins to improve above a coating level of about 2.0 wt%, and in another preferred embodiment the coating level Can be controlled within the range of about 2.5 to 4.0 weight percent. The higher the impact speed or the lower the temperature, the higher the coating level must be required to cause ductile failure (fracture). It appears that a coating level higher than 3.5% by weight is required to produce ductility at a test temperature of 0 (zero) ° C.

  Notched Izod impact strength increased linearly with coating level. As the coating level increased, the flexural modulus was not affected by the coating level while the tensile modulus increased. The reason is that the coating reduces the adhesion between the filler and the polymer. Applying tensile stress makes it easier for the filler particles to pull out of the polymer. It should also be noted that the tensile stress decreases as the coating level increases. Its pull-out force is lower than in the bending test and therefore the flexural modulus is not affected.

  To reliably improve the impact toughness of PLLA resin, a coating level of about 3.0 to 4.0% by weight appears to be the preferred coating range. Impact toughness balance improves as the coating level increases, but is in a trade-off relationship with tensile force and tensile modulus.

  By using the coated calcium carbonate filler disclosed herein, the toughness of the PLA resin can be improved by as much as 10 times that of the unfilled resin. Stearic acid as a coating material for calcium carbonate filler is only an example, and other fatty acid coatings would be expected to provide similar improvements in the toughness of the resin.

Example 3
A variable (different) thickness PLA test strip containing variable (different) amounts of coated calcium carbonate, along with a variable gap die and variable speed strip puller, single screw It was produced on a Brabender Intellitorque using an extruder. Its mechanical properties were measured at 23 ° C. using a Gardner impact test and an Elmendorf Tear test. The results are shown in FIGS. 8 and 9 and show that the filler has a significant (significant) increase in Gardner impact resistance. FIG. 8 shows the average drop (decrease) height required to cause failure for PLA samples containing varying amounts of coated filler.

  FIG. 9 shows the force required to propagate the tear (tear) from the Elmendorf tear test of various samples of PLA with coated filler, and shows the significant amount of tear strength in the filled sample. : Significant) increase.

  The aspect ratio distribution of the material was measured by a TEM micrograph as previously described in the text and shown in FIG.

Example 4
A PLA containing the coated additive was prepared as in Example 1. The test strips were similar to those of Example 3 with target thicknesses of 4 mils (mil) (0.102 mm), 9 mils (mil) (0.229 mm), and 15 mils (mil) (0.381 mm). Generated.

  FIG. 10 shows the impact strength of the test strip Gardner. FIG. 11 shows the tear (break) strength of Elmendorf. These figures show that toughness decreases empirically in the absence of additives, whereas the presence of additives increases toughness as sheet thickness increases. By increasing the Gardner impact strength, the thickness to achieve comparable mechanical properties can be reduced by 3 to 4 times (times).

Example 5
The compound (composite) obtained by the process set forth in Example 1 containing various amounts of filler was injection molded in an Arburg Allrounder 370c injection molding machine and ASTM A sample conforming to (standard) was generated.

  FIG. 12 shows the bending elastic modulus of each sample. FIG. 13 shows the multiaxial impact total fracture energy at room temperature measured by a multiaxial impact tester (tester) equipped with an Instron Corporation Dynatup 9250HV instrument. It shows the impact energy and ductility improvements required for failure achieved when using 15 to 35 wt.% Coated filler.

  These figures show that the additive significantly improved (significantly) the toughness and stiffness of the polylactide, and that addition of the additive converted brittle failure into ductile failure.

Example 6
The crystallization kinetics of PLA samples containing 30% by weight of EMforce® Bio at various temperatures were compared to unfilled PLA samples.

  FIG. 14 shows the crystallisation half time from the molten state and the result measured by differential (difference) scanning calorimetry, and shows the half crystallization time from the molten state. It shows that a significant (significant) reduction can be achieved by the present invention.

Example 7
FIG. 15 shows 0, 10, 15, 20, 25, 30 and 40 wt. The melt viscosity (viscosity) and the results of PLA, including (registered trademark) Bio) are shown, indicating that the additive significantly reduces the melt viscosity.

FIG. FIG. FIG. FIG. FIG. FIG. FIG. FIG. FIG. FIG. FIG. FIG. FIG. FIG. FIG.

Claims (53)

A bioplastic composition comprising a biopolymer comprising 10 to 40% by weight of coated inorganic particles,
The particles are one of fatty acids, fatty acid derivatives, rosins, rosinates, polyolefin waxes, oligomers and mineral oils, and combinations thereof in an amount of about 2.3 wt% or more based on the weight of the particles. A bioplastic composition that is coated with more than a seed. A bioplastic composition comprising 10 to 40 wt% filler,
The filler consists of inorganic particles coated with a dispersant,
The bioplastic composition, wherein the filler is coated with a dispersant containing less than 1% by weight of water at 200 ° C.   The bioplastic composition according to claim 1 or 2, wherein the coating material is stearic acid or a derivative thereof.   The bioplastic composition according to any one of claims 1 to 3, wherein the inorganic particles are made of calcium carbonate.   The bioplastic composition according to claim 4, wherein the calcium carbonate particles are selected from the group consisting of precipitated calcium carbonate, heavy calcium carbonate, and mixtures thereof.   The bioplastic according to any one of claims 1 to 5, wherein the inorganic particles include one of polycarbonate, silica, kaolin, talc, wollastonite, fine metal particles, glass microspheres, and combinations thereof. Composition.   The bioplastic composition according to any of claims 1 to 6, wherein the coating level is in the range of about 2.3 to 10.0 wt%.   The bioplastic composition of claim 7, wherein the coating level is in the range of about 2.3 to 4.0 wt%.   The bioplastic composition according to any one of claims 1 to 8, wherein the biopolymer is polylactide.   The biopolymer is one selected from polylactide (PLA), polyglyconate, poly (dioxanone), polyhydroxyalkanoate (PHA), polymeric starch polymer resin, and combinations thereof. The bioplastic composition according to any one of 1 to 9.   The bioplastic composition according to any one of claims 1 to 10, wherein the filler is a precipitated calcium carbonate in the form of needles having an aspect ratio greater than 4.   The bioplastic composition of claim 11, wherein the aspect ratio is greater than 5.   The bioplastic composition according to any one of claims 1 to 12, wherein the filler is calcium carbonate, and at least 90% of the particles have a size of 20 µm or less.   14. The bioplastic composition according to claim 13, wherein at least 90% of the particles have a size of 18 [mu] m or less.   15. The bioplastic composition according to claim 13 or 14, wherein at least 90% of the particles have a size of 2 [mu] m or less.   The bioplastic composition according to any one of claims 1 to 14, which is substantially free of other additives.   An automobile part comprising the bioplastic according to any one of claims 1 to 16.   A household electrical appliance component comprising the bioplastic according to any one of claims 1 to 16.   The electronic device component containing the bioplastic in any one of Claims 1 thru | or 16.   A consumer product comprising the bioplastic according to any one of claims 1 to 16.   A packaging product comprising the biopolymer (bioplastic) according to any one of claims 1 to 16.   The food tray and container according to claim 21.   A film and a bag comprising the bioplastic according to any one of claims 1 to 16.   24. A film according to claim 23 comprising an agricultural mulching film.   A garbage bag comprising the bioplastic according to any one of claims 1 to 16. A method for increasing the toughness of a bioplastic,
Supplying a biopolymer in the form of a resin,
Into the biopolymer resin, inorganic additive particles coated with a coating material having a coating level of about 2.3% by weight or more are mixed.
The method wherein the coating material is selected from among fatty acids, fatty acid derivatives, rosins, rosinates, polyolefin waxes, oligomers and mineral oils, and combinations thereof.   27. The method of claim 26, wherein the inorganic additive particles are calcium carbonate particles.   28. The method of claim 27, wherein the calcium carbonate particles are selected from the group consisting of precipitated calcium carbonate, heavy calcium carbonate, and mixtures thereof.   29. A method according to any of claims 26 to 28, wherein the coating material is stearic acid or a derivative thereof.   30. A method according to any of claims 26 to 29, wherein the coating level is in the range of about 2.3 to 10.0 wt%.   32. The method of claim 30, wherein the coating level is in the range of about 2.3 to 4.0 weight percent.   32. A method according to any of claims 26 to 31 wherein the coated inorganic additive particles comprise less than 1 wt% moisture at 200 <0> C.   33. A method according to any of claims 26 to 32, wherein the biopolymer is polylactide.   34. A method according to any of claims 26 to 33, wherein the mixed material is processed by injection molding or extrusion.   35. The method of claim 34, wherein the material is extruded to form a film.   36. A method according to any of claims 32 to 35, wherein the mixed material is treated at a temperature in the range of 180C to 210C.   37. A method according to any of claims 26 to 36, wherein the material is thermoformed.   Of inorganic particles coated with one or more of fatty acids, fatty acid derivatives, rosins, rosinates, polyolefin waxes, oligomers and mineral oils, and combinations thereof to improve the toughness and ductility of bioplastics use.   39. Use according to claim 38, wherein the inorganic particles are in the range of 10 to 40% by weight, based on the combined (total) weight of the coated inorganic particles and the biopolymer.   40. Use according to claim 38 or 39 of 2.3 to 10% by weight of said inorganic particles coated, based on the combined (total) weight of said coated inorganic particles and said biopolymer. Wherein the inorganic particles are calcium carbonate, wherein the coating consists of a fatty acid or a derivative thereof to C ₁₀ to C _22, Use according to any one of claims 38 to 40.   42. Use according to claim 41, wherein the calcium carbonate is a precipitated calcium carbonate in the form of needles having an aspect ratio greater than 4.   43. Use according to claim 41 or 42, wherein at least 90% of the calcium carbonate particles have a size of 20 [mu] m or less.   44. Use according to claim 43, wherein at least 90% of the calcium carbonate particles have a size of 2 [mu] m or less.   45. Use according to any of claims 38 to 44, wherein the coated inorganic particles have a moisture content of less than 1 wt% at 200C.   Inorganic particles coated with one or more of fatty acids, fatty acid derivatives, rosins, rosinates, polyolefin waxes, oligomers and mineral oils, and combinations thereof to promote crystallization from the molten state of the biopolymer Use of.   47. Use according to claim 46, wherein 10-40% by weight of the inorganic particles, based on the combined (total) weight of the coated inorganic particles and the biopolymer.   48. Use according to claim 46 or 47 of 2.3 to 10% by weight of said inorganic particles coated, based on the combined (total) weight of said coated inorganic particles and said biopolymer. Wherein the inorganic particles are calcium carbonate, wherein the coating consists of a fatty acid or a derivative thereof to C ₁₀ to C _22, Use according to any one of claims 38 to 48.   50. Use according to claim 49, wherein the calcium carbonate is a precipitated calcium carbonate in the form of needles having an aspect ratio greater than 4.   51. Use according to claim 49 or 50, wherein at least 90% of the calcium carbonate particles have a size of 20 [mu] m or less.   52. Use according to claim 51, wherein at least 90% of the calcium carbonate particles have a size of 2 [mu] m or less.   53. Use according to any of claims 46 to 52, wherein the coated inorganic particles have a water content of less than 1% by weight at 200C.

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