WO2002053640A1 - Compositions polymeriques biodegradables sensibles a l'eau et leur procede de preparation - Google Patents

Compositions polymeriques biodegradables sensibles a l'eau et leur procede de preparation Download PDF

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Publication number
WO2002053640A1
WO2002053640A1 PCT/US2001/047494 US0147494W WO02053640A1 WO 2002053640 A1 WO2002053640 A1 WO 2002053640A1 US 0147494 W US0147494 W US 0147494W WO 02053640 A1 WO02053640 A1 WO 02053640A1
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WIPO (PCT)
Prior art keywords
polymer
water
poly
grafted
composition
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PCT/US2001/047494
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English (en)
Inventor
David M. Shertz
James H. Wang
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Kimberly-Clark Worldwide, Inc.
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Application filed by Kimberly-Clark Worldwide, Inc. filed Critical Kimberly-Clark Worldwide, Inc.
Priority to MXPA03005806A priority Critical patent/MXPA03005806A/es
Priority to DE10197119T priority patent/DE10197119T5/de
Priority to GB0313501A priority patent/GB2387388B/en
Priority to KR10-2003-7008726A priority patent/KR20030068567A/ko
Priority to BR0116614-0A priority patent/BR0116614A/pt
Publication of WO2002053640A1 publication Critical patent/WO2002053640A1/fr

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    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
    • D01F6/58—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products
    • D01F6/62—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products from polyesters
    • D01F6/625—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products from polyesters derived from hydroxy-carboxylic acids, e.g. lactones
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L101/00—Compositions of unspecified macromolecular compounds
    • C08L101/02—Compositions of unspecified macromolecular compounds characterised by the presence of specified groups, e.g. terminal or pendant functional groups
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L51/00—Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
    • C08L51/08—Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers grafted on to macromolecular compounds obtained otherwise than by reactions only involving unsaturated carbon-to-carbon bonds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
    • C08L67/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
    • C08L67/04—Polyesters derived from hydroxycarboxylic acids, e.g. lactones

Definitions

  • the present invention relates to modified, hydrolytically biodegradable polymers and methods of making modified, hydrolytically biodegradable polymers. More particularly, the present invention relates to a biodegradable polymer selected from poly(hydroxy alkanoates), poly(alkylene succinates) or polycaprolactone modified with a polar monomer and a process of modifying those polymers. In a preferred embodiment, the invention relates to a method of grafting polar functional groups onto a biodegradable polymer selected from poly( ⁇ -hydroxybutyrate-co-valerate), poly(butylene succinate) or polycaprolactone and grafted polymer compositions produced by the method.
  • plastics hereinafter polymers
  • polymers used in a variety of consumer goods, packaging and medical articles has not significantly increased over the past twenty years, the common perception is that more and more non-degradable plastics are filling up our limited landfill space.
  • polymers continue to be used in the manufacture of consumer goods, packaging and medical articles because plastics offer many advantages over the more traditional materials: wood, glass, paper, and metal.
  • the advantages of using polymers include decreased manufacturing time and costs, improved mechanical and chemical properties, and decreased weight and transportation costs. It is the improved chemical resistance properties of the majority of plastics that result in their non-degradability.
  • waste materials including food waste, packaging materials and medical waste
  • a typical landfill provides a relatively stable environment in which none of these materials is seen to decompose at an appreciable rate.
  • Alternative waste disposal options have been increasingly discussed and utilized to divert some fractions of waste from entombment. Examples of these alternatives include municipal solid waste composting, anaerobic digestion, enzymatic digestion, and waste water sewage treatment.
  • medical waste can be categorized as either reusable or disposable. Categorization as to whether certain waste is reusable or disposable is customarily determined according to the material from which the article was constructed and the purpose for which the article was used.
  • disposable medical articles are usually only used once. Even then, disposing procedures are not straightforward, rather they often involve several steps to safeguard against potential hazards.
  • disposable medical articles must be disinfected or sterilized, adding a significant cost prior to disposal into a specially designated landfill or waste incinerator. As a result, the disposal cost for the contaminated single use articles is quite high.
  • single use medical articles are desirable because of the assurance of clean, and uncontaminated equipment.
  • sterilization procedures conducted improperly can result in detrimental effects, such as the transmission of infectious agents from one patient to another. Improper sterilization can also be disastrous in a laboratory setting, where, for example, contaminated equipment can ruin experiments resulting in tremendous costs of time and money.
  • thermoplastic fibers such as polyethylene, polypropylene, polyesters, polyamides and acrylics.
  • These fabrics can also include mixtures of thermoset fibers, such as polyamides, polyarimides and cellulosics. They are typically 10-100 grams per square yard in weight and can be woven, l ⁇ iitted or otherwise formed by methods well known to those in the textile arts while the non-wovens can be thermobonded, hydroentangled, wet laid or needle punched and films can be formed by blown or cast extrusion or by solution casting. Once used, these fabrics are difficult and costly to dispose of and are non-degradable.
  • polymers for various disposable articles are widespread and well known in the art.
  • the heaviest use of polymers in the form of films and fibers occurs in the packaging and the disposable article industries.
  • Films employed in the packaging industry include those used in food and non-food packaging, merchandise bags and trash bags.
  • the disposable article industry the general uses of polymers occurs in the construction of diapers, personal hygiene articles, surgical drapes and hospital gowns, instrument pads, bandages, and protective covers for various articles. In light of depleting landfill space and inadequate disposal sites, there is a need for polymers that are water- responsive.
  • polymers such as polyethylene, polypropylene, polyethylene terephthalate, nylon, polystyrene, polyvinyl chloride and polyvinylidene chloride
  • polymers are not water-responsive.
  • these polymers are generally non-compostable, which is undesirable from an environmental perspective.
  • Polymers and polymer blends have been developed which are generally considered to be water- responsive. These are polymers which purportedly have adequate properties to permit them to breakdown when exposed to conditions which lead to composting. Examples of such arguably water-responsive polymers include those made from starch biopolymers and polyvinyl alcohol.
  • Personal care products such as diapers, sanitary napkins, adult incontinence garments, and the like are generally constructed from a number of different components and materials. Such articles usually have some component, usually the backing layer, constructed of a liquid repellent or water- barrier polymer material.
  • the water-barrier material commonly used includes polymer materials, such as polyethylene film or copolymers of ethylene and other polar and non-polar monomers.
  • the purpose of the water-barrier layer is to minimize or prevent absorbed liquid that may, during use, exude from the absorbent component and soil the user or adjacent clothing.
  • the water-barrier layer also has the advantage of allowing greater utilization of the absorbent capacity of the product.
  • the liquid repellent material may disrupt operations by plugging screens and causing sewage disposal problems.
  • the packaging in which the disposable article is distributed is also made from a water-barrier, specifically water-resistant, material. Water-resistivity is necessary to prevent the degradation of the packaging from environmental conditions and to protect the disposable articles therein.
  • this packaging may be safely stored with other refuse for commercial disposal, and especially in the case of individual packaging of the products, it would be more convenient to dispose of the packaging in the toilet with the discarded, disposable article.
  • the aforementioned problems persist.
  • lactic acid and lactide to manufacture a water-stable polymer
  • Such polymers have been used in the past for making water- stable sutures, clamps, bone plates and biologically active controlled release devices. Processes developed for the manufacture of such polymers to be utilized in the medical industry have incorporated techniques which respond to the need for high purity and biocompatibility in the final product.
  • lactide polymers or poly(lactides) are unstable.
  • the consequence of this instability has several aspects.
  • One aspect is the biodegradation or other forms of degradation which occur when lactide polymers, or articles manufactured from lactide polymers, are discarded or composted after completing their useful life.
  • Another aspect of such instability is the degradation of lactide polymers during processing at elevated temperatures as, for example, during melt processing by end-user purchasers of polymer resins.
  • compositions comprised of multi-layer polymer films are known in the art.
  • the utility of such structures lies in the manipulation of physical properties in order to increase the stability or lifetime during use of such structure.
  • U.S. Pat. No. 4,826,493 describes the use of a thin layer of hydroxybutyrate polymer as a component of a multi-layer structure as a barrier film for diaper components and ostomy bags.
  • the controlled release compositions are comprised of a therapeutically effective agent in a carrier consisting of particles of a polymer of limited water solubility dispersed in a water-soluble polymer.
  • the carrier of these inventions includes the use of more than one polymer, the disclosed carrier is not a blend because the polymer of limited water solubility is incorporated in the water-soluble polymer as particles ranging in average particle size from 1 to 500 microns.
  • the use of polymers for use in water-responsive articles is disclosed in U.S. Pat. Nos.
  • compositions of this group consist of articles constructed from polymers which are first formed into fibers or films and then combined. As such, the compositions are actually mini-layers of the individual polymer films or fibers. Therefore, although the fibers and films of the polymers of such compositions are considered to be in very close proximity with one another, they are not as intimate as actual polymer blends. The dispersion of one polymer within another in these compositions is not viewed as approximately uniform since the individual polymers are essentially distinct and separate fibers or films.
  • U.S. Pat. No. 5,525,671 to Ebato et al. discloses a method of making a linear lactide copolymer from a lactide monomer and a hydroxyl group containing monomer.
  • the polymer disclosed by Ebato is a linear lactide copolymer produced by reacting two monomers to form a linear polymer with a block or random structure. Ebato does not disclose graft copolymers.
  • Polymer blend compositions for making fibers and films that are optimally combined are desirable because they are highly stable. Optimal combination of polymers means that the polymers are connected as closely as possible without the requirement of co-polymerization. Although physically blended individual polymer compositions are known, improved polymer blends within the fibers and films the individual fibers are microscopically intimately interfaced are desirable since the resulting composition is then more stable, pliable and versatile and most importantly having improved properties and performance.
  • graft copolymers of this invention includes, but would not be limited to, materials having a greater affinity for a polar coating. Therefore, it is an object of this invention to provide a modified, hydrolytically biodegradable polymer.
  • Another object of this invention is to provide a thermally processable polymer.
  • Another object of this invention is to provide a commercially viable polymer.
  • Yet another object of this invention is to provide a modified, hydrolytically biodegradable polymer useful for making blends with improved mechanical and physical properties.
  • Another object of this invention is to provide a modified biodegradable polymer with improved melt processability.
  • a further object of this invention is to provide a polymer blend of unique microstructure.
  • Another object of this invention is to provide a modified biodegradable polymer which has improved compatibility in blends with polar polymers.
  • Another object of the invention is to provide improved polymer blends comprising poly( ⁇ -hydroxybutyrate- co-valerate), poly(butylene succinate) and/or polycaprolactone.
  • This invention discloses modified polymer compositions comprised of a biodegradable polymers selected from poly(hydroxy alkanoates), poly(alkylene) succinates or polycaprolactone grafted with a polar monomer, oligomer, or polymer.
  • This invention describes compositions of a polymer selected from poly(hydroxy alkanoates), such as poly( ⁇ - hydroxybutyrate), poly( ⁇ -hydroxybutyrate-co- ⁇ - hydroxyvalerate); poly(alkylene succinates), such as poly(butylene succinate) and poly(ethylene succinate), or polycaprolactone grafted with 2-hydroxyethyl methacrylate or poly(ethylene glycol) methacrylate and a reactive extrusion process for making modified polymer compositions.
  • P ⁇ ly( ⁇ -hydroxybutyrate-co-valerate), poly(butylene succinate), poly(ethylene succinate) and polycaprolactone are biodegradable polymers which are commercially viable and, in general, thermally processable.
  • the resulting modified polymer is more compatible with polar polymers and other polar substrates.
  • the modified polymer compositions of this invention have enhanced compatibility with water-soluble polymers, such as polyvinyl alcohol and polyethylene oxide, than the unmodified biodegradable polymers.
  • the compatibility of modified polymer compositions of the present invention with a polar material can be controlled by the selection of the monomer, the level of grafting and the blending process conditions. Tailoring the compatibility of blends with modified polymer compositions leads to better processability and improved physical properties of the resulting blend.
  • compositions disclosed in this invention have the unique advantage of being biodegradable so that the compositions and articles made from the compositions can be degraded in aeration tanks by aerobic degradation and anaerobic digestors by anaerobic degradation in wastewater treatment plants. Therefore, articles made from the compositions of this invention will not significantly increase the volume of sludge accumulated at wastewater treatment plants.
  • a water-sensitive homogeneous polymer blend composition comprising a biodegradable polymer grafted with a polar monomer, oligomer, or polymer or a combination thereof and a water-soluble polymer.
  • a novel polymer composition comprising a blend of a first biodegradable polymer grafted with a polar monomer, oligomer, or polymer or a combination thereof and a second biodegradable polymer grafted with a polar monomer, oligomer, or polymer or a combination thereof, wherein said first and second biodegradable polymers are different polymers.
  • FIG. 1 is a graph of the torque versus time during reactive extrusion of an embodiment of the present invention.
  • Fig. 2 is a comparative proton NMR spectra for unmodified PHBV and for PHBV grafted with HEMA.
  • Fig. 3 is a graph of the apparent melt viscosities at various apparent shear rates and rheology curves for unmodified PHBV and the HEMA grafted PHBV of Example 1.
  • Fig. 4 is a graph of DSC curves for PHBV and HEMA grafted PHBV.
  • Fig. 5 is a graph of the torque versus time during a reactive extrusion of two PEG-MA grafted PBS samples of Example 2.
  • Fig. 6 is comparative proton NMR spectra for unmodified and grafted PBS from reactive extrusion on the Haake extruder of Example 2.
  • Fig. 7 is a graph of the melt rheology curves for unmodified PBS and PEG-MA grafted PBS on the Haake extruder of Example 2.
  • Fig. 8 is a graph of the melt rheology curves for unmodified PBS and HEMA grafted PBS on the ZSK-30 extruder of Example 2.
  • Fig. 9 is a graph of DSC curves for unmodified PBS and PEG-MA grafted PBS of Example 2.
  • Fig. 10 is a graph of DSC curves for ungrafted PBS and HEMA grafted PBS of Example 2.
  • Fig. 1 1 is a SEM (Scanning electron microscopy) image of the topological morphology of the fracture surface of a film made from a 60/40 blend of PBS/PEO showing a two- phase microstructure.
  • Fig.12 is a SEM image of the topological morphology of the fracture surface of a film made from a 60/40 blend of grafted PBS/grafted PEO showing a two-phase microstructure and improved compatibility.
  • Fig. 13 is a SEM image using BEI (back-scattered electron imaging) of the topological morphology of the fracture surface of a film made from a 60/40 blend of PBS/PEO showing a two-phase microstructure.
  • BEI back-scattered electron imaging
  • Fig. 14 is a SEM image using BEI (back-scattered electron imaging) of the topological morphology of the fracture surface of a film made from a 60/40 blend of grafted
  • Fig.15 is a graph of a DSC analysis of PBS/PEO blends showing the observed decrease in T m for the PEO phase of the PBS/PEO reactive blends as percent PEO in the blends was increased.
  • Fig. 16 is a graph of a DSC analysis of PBS/PEO blends showing an increase in change of T m ( ⁇ T m ) for the PEO phase of the reactive blends compared to physical blends as the percent PEO in the blends was increased.
  • Fig.17 is a graph of a DSC analysis of PBS/PEO blends showing a comparison between the DSC curves for
  • Fig. 18 is a graph of the melt rheology curves
  • the present invention comprises a biodegradable polymer which is modified by graft polymerization with apolar monomer, oligomer, or polymer.
  • the present invention also comprises a polymer composition which includes a blend of a biodegradable polymer which is modified by graft polymerization with a polar monomer, oligomer, or polymer and either a water-sensitive polymer or another biodegradable polymer which is modified by graft polymerization with a polar monomer, oligomer, or polymer.
  • the resulting polymer composition can be fabricated into films, fibers, coatings, beads, powders, and the like and can be used to make fabrics, garments, and articles, such as drapes, towels, covers, overwraps, gowns, head coverings, face masks, shoe coverings, CSR wraps, sponges, dressings, tapes, underpads, liners, wash cloths, sheets, pillow covers, napkins, cloth-like outercovers, surgical products and a wound care products.
  • fabrics, garments, and articles such as drapes, towels, covers, overwraps, gowns, head coverings, face masks, shoe coverings, CSR wraps, sponges, dressings, tapes, underpads, liners, wash cloths, sheets, pillow covers, napkins, cloth-like outercovers, surgical products and a wound care products.
  • the present invention is also particularly suitable for use for biodegradable personal care products, such as diapers, training pants, feminine tampons, pads and pantiliners, and baffle films therefor, adult incontinence products, wet wipes and/or wipers and any woven, non-woven, or otherwise formed materials.
  • biodegradable personal care products such as diapers, training pants, feminine tampons, pads and pantiliners, and baffle films therefor, adult incontinence products, wet wipes and/or wipers and any woven, non-woven, or otherwise formed materials.
  • Such products can be employed in the medical industry, both in hospitals and outpatient facilities and in home environments.
  • Biodegradable polymers that are useful in the present invention include poly( ⁇ -hydroxy alkanoates) (“PHA”), such as poly( ⁇ -hydroxybutyrate) (“PHB”), poly( ⁇ - hydroxybutyrate-co- ⁇ -hydroxyvalerate) (“PHBV”); poly(alkylene succinates) (“PAS”), such as poly(ethylene succinate) (“PES”) and poly(butylene succinate) (“PBS”); and polycaprolactones (“PCL”) that are hydrolytically degradable.
  • PHA poly( ⁇ -hydroxy alkanoates)
  • PBS poly( ⁇ -hydroxybutyrate)
  • PBS poly(butylene succinate)
  • PCL polycaprolactones
  • PHBV resins can be made by either the fermentation process of carbohydrate and an organic acid by a microorganism; e.g., Alcaligenes eutrophus, or by the use of transgenic plants.
  • a microorganism e.g., Alcaligenes eutrophus
  • PHBV Biodegradable Plastics from Plants
  • CHEMTECH September 1996, ppgs. 38-44.
  • PHBV is a biodegradable polymer and has the chemical structure:
  • the molecular weight of PHBVs useful in the present invention is not critical to the present invention and can generally be approximately 20,000 to 2,000,000 grams per mol.
  • the PHBV compositions described in the following examples were made by using a grade of PHBV purchased from Zeneca Bio-Products of Wilmington, Delaware, under the designation Biopol ® D600G.
  • the PHBV purchased from Zeneca Bio- Products is biodegradable. Any PHBV can be selected for use in this invention, and the molecular weights of the PHBV may vary depending on the desired properties and use.
  • Polyalkylene succinate (“PAS”) resins are produced by different synthetic methods, such as the reaction product between aliphatic dicarboxylic acids and ethylene glycol or butylene glycol.
  • Poly(butylene) succinate (“PBS”) is commercially available from Showa Highpolymer Company of Tokyo, Japan, under the trademark Bionolle ® .
  • PBS is a biodegradable polymer and has the chemical structure:
  • the molecular weight of PAS useful in the present invention is not critical to the present invention and can generally be approximately 20,000 to 2,000,000 grams per mole.
  • PCL Polycaprolactone
  • Tone ® available from Union Carbide of Danbury, Connecticut and is a biodegradable polymer with the following chemical structure:
  • the molecular weight of PCL useful in the present invention is not critical to the present invention and can generally be approximately 50,000 to 1,000,000 grams per mole.
  • the PCL compositions described in the following examples were made by using P-767 and P-787 PCL purchased from Union Carbide Corporation of Danbury, Connecticut (Tone ® polymers Catalog number UC-261).
  • the PCL purchased from Union Carbide Corporation is biodegradable and has a melt flow of 1.9 ⁇ 0.3 g/min. for P-767 (8 ⁇ C, 44 psi, ASTM 1238-73) and 1.0 ⁇ 0.2 g/min. (125 C, 44 psi).
  • Any PCL can be selected for use in this invention, and the molecular weights of the PCL may vary depending on the desired properties and use.
  • Polar monomers, oligomers, or polymers useful in the present invention include ethylenically unsaturated monomers containing a polar functional group, such as hydroxyl, carboxyl, halo-, glycidyl, cyano, amino, carbonyl, thiol, sulfonic, sulfonate, and the like are appropriate for this invention.
  • a polar functional group such as hydroxyl, carboxyl, halo-, glycidyl, cyano, amino, carbonyl, thiol, sulfonic, sulfonate, and the like are appropriate for this invention.
  • polar vinyl monomers useful in the present invention include, but are not limited to, poly(ethylene glycol) acrylate, polyethylene glycol) alkyl ether acrylate, poly(ethylene glycol) methacrylate, poly(ethylene glycol)alkyl ether methacrylate, acrylic acid, maleic anhydride, itaconic acid, sodium acrylate, 3 -hydroxypropyl methacrylate, 2- hydroxyethyl methacrylate, 3 -hydroxypropyl acrylate, 2- hydroxyethyl acrylate, acrylamide, 2-bromoethyl methacrylate, 2-chloroethyl methacrylate, 2-iodoethyl methacrylate, 2- bromoethyl acrylate, 2-chloroethyl acrylate, 2-iodoethyl acrylate, glycidyl methacrylate, 2-cyanoethyl acrylate, glycidyl acrylate, 4-nitrophenyl
  • the grafted biodegradable polymer may contain about 1 to 20 weight percent of grafted polar monomers, oligomers, or polymers.
  • the grafted biodegradable polymer contains about 2.5 to 20 weight percent of grafted polar monomers, oligomers, or polymers, and most preferably about 2.5 to 10 weight percent of grafted polar monomers, oligomers, or polymers.
  • HEMA Aldrich Catalog number 12,863- 8
  • PEG-MA Aldrich Catalog number 40,954-5
  • the PEG-MA purchased from Aldrich Chemical Company was polyethylene glycol) ethyl ether methacrylate having a number average molecular weight of approximately 246 grams per mole.
  • Analogs of HEMA and PEG-MA are also useful in the present invention.
  • Analogs of HEMA include, for example 3- hydroxypropyl methacrylate and 4-hydroxybutyl methacrylate; analogs of PEG-MA have molecular weights ranging from about 200 g/mole to about 10,000 g/mole.
  • the method for making the grafted biodegradable polymer compositions has been demonstrated by a reactive- extrusion process.
  • the grafting reaction can also be performed in other reaction devices as long as the necessary mixing of biodegradable polymer and polar monomer and any other reactive ingredients is achieved and enough energy is provided to effect the grafting reactions; i.e., by creating free radicals to initiate the grafting reaction process.
  • the reactions are desirably conducted in the polymer melt phase; i.e., in the absence of bulk solvent. This is a highly effective process since the solvent removal step is not needed in the process.
  • compositions of this invention include initiators, such as
  • acyl peroxides such as benzoyl peroxide; dialkyl, diaryl, or aralkyl peroxide, such as di-t-butyl peroxide; dicumyl peroxide; cumyl butyl peroxide; 1,1 -di-t-butyl peroxy-3,5,5- trimethylcyclohexane; 2,5-dimethyl-2,5-di(t-butyfperoxy) hexane; 2,5-dimethyl-2,5-bis-(t-butylperoxy) hexyne-3 and bis(a-t-butyl peroxyisopropylbenzene); peroxyesters such as t- butyl peroxypivalate; t-butyl peroctoate; t-butyl perbenzoate;
  • the amount of free radical initiator in the total mixture compositions which include either biodegradable polymers and/or water-soluble polymers and a polar monomer or a polar vinyl monomer mixture range from about 0.1 to about 1.5 weight percent. At too low an amount of freeradical initiator, there is not sufficient initiator present to initiate a grafting reaction. If the amount of free radical initiator is too high, it will create undesirable cross-linking of the polymer composition. Cross-linked polymers are undesirable in the present invention because they cannot be processed into films, fibers or other useful products.
  • graft polymers of this invention may be added to the graft polymers of this invention to further enhance the properties of the final material.
  • polyethylene glycol may be further added to improve melt flow by reducing melt viscosity.
  • Additives of other types may also be incorporated to provide specific properties as desired.
  • anti-static agents, pigments, colorants and the like may be incorporated into the polymer compositions.
  • processing characteristics may be improved by incorporating lubricants or slip agents into blends made from polymers of the invention. All of these additives are generally used in relatively small amounts, usually less than 3 weight percent of the final composition.
  • the mixture of the biodegradable polymer and the polar monomer, oligomer, or polymer is subjected to mechanical deformation in a suitable mixing device, such as a Brabender Plasticorder, a roll mill, a single or multiple screw extruder, or any other mechanical mixing device which can be used to mix, compound, process or fabricate polymers.
  • a particularly desirable reaction device is an extruder having one or more ports.
  • the reaction device is a co-rotating, twin-screw extruder, such as a ZSK-30 twin- screw compounding extruder manufactured by Werner & Pfleiderer Corporation of Ramsey, New Jersey. This extruder allows multiple feeding and venting ports and provides high intensity distributive and dispersive mixing which are essential to produce grafted biodegradable polymers of uniform composition and homogeneous distribution of grafted side chains derived from polar vinyl monomers.
  • a novel polymer composition comprising a blend of a first biodegradable polymer grafted with a polar monomer, oligomer, or polymer or a combination thereof and a second biodegradable polymer grafted with a polar monomer, oligomer, or polymer or a combination thereof, wherein the first and second biodegradable polymers are different polymers.
  • the ratio of the two biodegradable polymers useful in the present invention is about 1 :99 and 99:1 by weight.
  • a desired first and second biodegradable polymer in this embodiment of the present invention is modified polylactide and modified PHBV. Amount of grafting monomer for either of the modified biodegradable polymers is about 1 to 20 percent by weight of the starting or non-grafted biodegradable polymer.
  • PHBV has a very low cooling rate, such that commercial use of this material is impractical.
  • PLA is too brittle for applications as disclosed herein.
  • a blend of PLA and PHBV makes the PHBV cool at an acceptable rate and also makes PLA more flexible such that these material can be used in the products disclosed herein; whereas, either biodegradable polymer alone was unsuitable for such applications.
  • blends of the modified biodegradable polymer of the present invention and water-soluble polymers may be made.
  • Such blends demonstrate increased water sensitivity of the composition which promoted the rate of hydrolytic degradation of the biodegradable polymers by increasing the exposed surface area of the biodegradable polymer following the dissolution of the water-soluble component.
  • Water-soluble polymers with which the modified biological polymers of the present invention can be blended include polyethylene oxide, polyvinyl alcohol, hydroxypropyl cellulose, polyacrylamide, sulfonated polyesters and polyacrylic acid.
  • the weight fraction of the modified biodegradable polymer in the blend ranges from 1% to 99% by weight. This fraction determines the water responsiveness of the blends.
  • a wide range of water responsiveness includes water-dispersibility, water- disintegratable, water-weakenable and water-stable, as those terms are defined hereinbelow.
  • biodegradable polymers or modified biodegradable polymers in blends used to make fibers, films or other shapes reduces the water sensitivity of pure water-soluble polymers, such as polyvinyl alcohol (“PVOH”) in use.
  • PVOH polyvinyl alcohol
  • Biodegradable polymers grafted with a polar monomer or a mixture of monomers is preferred for enhanced compatibility with highly polar water-soluble polymers, such as PVOH, in order to obtain superior processing and mechanical and physical properties. It is possible to use the blends to make other shapes than fibers or films and to thermally form the blends into complex shapes.
  • water-dispersible means that the composition dissolves or breaks into pieces smaller than the openings of a 20 mesh screen after being immersed in water for approximately five minutes.
  • water-disintegratable means that the composition breaks into multiple pieces within five minutes of immersion in water and that some of the pieces will be caught by a 20 mesh screen without slipping through in the same manner as a thread through the eye of a needle.
  • water-weakenable means that the composition remains in one piece but weakens and loses rigidity after five minutes of immersion in water and becomes drapeable; i.e., it bends without an external force applied thereto when it is held by one side at a horizontal position.
  • water-stable means that the composition does not become drapeable after five minutes of immersion in water and remains in one piece after the water response test.
  • graft copolymer means a copolymer produced by the combination of two or more chains of constitutionally or configurationally different features, one of which serves as a backbone main chain, and at least one of which is bonded at some point(s) along the backbone and constitutes a side chain.
  • the molar amount of grafted monomer, oligomer or polymer; i.e., side-chain species, may vary but should be greater than molar amount of the parent species.
  • grafted means a copolymer has been created which comprises side chains or species bonded at some point(s) along the backbone of a parent polymer.
  • blend as applied to polymers means an intimate combination of two or more polymer chains of constitutionally or configurationally different features which are not bonded to each other. Such blends may be homogeneous or heterogeneous. (Seesperling, L.H., Introduction to Physical Polymer Science 1986 pp. 44-47 which is herein incorporated by reference in its entirety.) Preferably, the blend is created by combining two or more polymers at a temperature above the melting point of each polymer.
  • One method is solution-based grafting method, in which a biodegradable polymer is dissolved in a solvent, to which desired amounts of a free radical initiator and a polar monomer or a mixture of two or more polar monomers, particularly polar vinyl monomers, are added. After sufficient grafting is completed, the solution is purified to remove the solvent and unreacted monomer, resulting in a grafted biodegradable polymer.
  • This method is relatively more labor-intensive and costly as compared to the melt grafting methods disclosed below.
  • the other method is based on a melt phase reaction in which a molten biodegradable polymer is reacted with a free radical initiator and a polar monomer or mixture of two or more polar monomers, particularly polar vinyl monomers.
  • the melt phase modification is termed "reactive extrusion" in that a new polymer species is created upon the modification reaction.
  • There are several specific methods for carrying out the grafting modification reaction in a melt First, all of the ingredients, including a biodegradable polymer, a free radical initiator, a polar monomer or a mixture of polar monomers in a predetermined ratio are added simultaneously to a melt mixing device or an extruder.
  • the biodegradable polymer may be fed to a feeding section of a twin screw extruder and subsequently melted, and a mixture of a free radical initiator and polar monomer or mixture of polar monomers, is injected into the biodegradable polymer melt under pressure, the resulting melt mixture is then allowed to react.
  • the biodegradable polymer is fed to the feeding section of a twin screw extruder, then the free radical initiator and polar monomer, or mixture of monomers, are fed separately into the twin screw extruder at different points along the length of the extruder.
  • the heated extruder extrusion is performed under high shear and intensive dispersive and distributive mixing resulting in a grafted biodegradable polymer of high uniformity.
  • the hydrolytically degradable and water-soluble polymer blend compositions according to the present invention are produced by a melt blending process. It is desired according to the present invention to blend or mix the two components in an extruder, such as a single-screw or twin- screw extruder under appropriate temperature and shear/pressure conditions to ensure mixing.
  • the blending process can also be performed in a batchwise mixing device, such as a melt mixer or a kneader.
  • the modified biodegradable polymer or water-soluble polymer, such as polyvinyl alcohol (“PVOH”) can be fed into the extruder/mixer either simultaneously or in sequence.
  • the present invention discloses selectively water responsive homogenous polymer blend compositions comprising modified biodegradable polymers and water-soluble polymer blends; e.g., modified biodegradable polymers, such as
  • homogeneous polymer blend composition means that the polymer blend forms a cohesive, continuous structure of modified biodegradable polymer and water-soluble polymer; e.g., polyvinyl alcohol, which is macroscopically homogeneous Microscopically, the size of the dispersed phase is on the order of several microns or less.
  • a homogenous polymer blend composition can be achieved by the mixing of modified biodegradable polymer and water-soluble polymer; e.g., polyvinyl alcohol, at temperatures above the melting point of the polymer having the highest melting point, and below the decomposition point of the polymer having the lowest decomposition point, in order to form a homogeneous molten mixture of the polymers (prior to cooling to a solid form; e.g., films or fibers).
  • modified biodegradable polymer and water-soluble polymer e.g., polyvinyl alcohol
  • the polymer having the higher melting point is polyvinyl alcohol and the polymer having the lower decomposition point is also polyvinyl alcohol.
  • the melting point for polyvinyl alcohol is generally approximately between 180-190° C, and more specifically around 183° C.
  • the decomposition point of polyvinyl alcohol is approximately 210° C.
  • the resulting composition resembles islands of PHBV grafted with HEMA in a sea of polyvinyl alcohol, for example, and at a microscopic level has the appearance of approximately uniform distribution of HEMA grafted PHBV among polyvinyl alcohol.
  • the homogeneous polymer blend composition of the present invention therefore has a very fine dispersion of graft modified biodegradable polymer islands of average size of less than about 0.3-0.4 microns dispersed within a water-soluble polymer.
  • the "polymer blend” of the present invention is distinguishable from “blended polymers.”
  • the compositions of the present invention comprise polymers that are blended above the melting point of the polymer having the highest melting point (e.g., >183° C for polyvinyl alcohol), and below the decomposition points of the polymer having the lowest decomposition point (210° C for polyvinyl alcohol) and under high shear; i.e., at a shear rate of 100 s "1 or higher.
  • the homogeneous polymer blend composition therefore, is formed prior to the polymers being formed into films or fibers, resulting in compositions of polymers which are highly, and intimately interconnected, having a selectively uniform dispersion.
  • compositions are distinguishable from those comprising blended polymers that consist of polymers which are blended after they have been formed into fibers or films, resulting in compositions which do not have approximate uniform dispersion and often appearing as individual polymers layered or mixed together.
  • blended polymers that consist of polymers which are blended after they have been formed into fibers or films, resulting in compositions which do not have approximate uniform dispersion and often appearing as individual polymers layered or mixed together.
  • microstructure of the polymer blends refers specifically to the size and distribution of graft modified biodegradable polymer islands within the water-soluble polymer sea, for example.
  • the size of the islands may vary from approximately 0.1 to 5.0 ⁇ m.
  • the composition gains greater wet mechanical strength and loses pliability in water.
  • the islands are typically small (approximately 0.2-1.0 ⁇ m), and are distributed so that they are far apart from each other.
  • the method of making films of the present invention effects the morphology of the film.
  • a non-orienting method is thermomechanical pressing. An example of thermomechanical pressing is described in the examples below.
  • Orienting methods of making films result in films with in which the dispersed phase has a morphology that contains graft modified biodegradable polymer extended into a fibrous structure through the water-soluble polymer continuous phase.
  • Oriented films have reduced water responsiveness and are not dispersible in cold water but are only cold-water weakenable or cold-water disintegratable.
  • the present invention provides improved compositions and methods of making compositions with improved morphologies and cold-water responsiveness.
  • One embodiment of the present invention is a homogeneous polymer blend composition
  • a homogeneous polymer blend composition comprising from about 1 to about 35 weight percent graft modified biodegradable polymer and from about 65 to about 99 weight percent water-soluble polymer, wherein such composition is water dispersible.
  • the composition is characterized by a morphology of fine graft modified biodegradable polymer particles dispersed in a continuous phase of water-soluble polymer.
  • water dispersible means that the composition will dissolve or break into pieces smaller than a 20 mesh after being tested with water at room temperature (18-22° C) for 2 minutes.
  • Testing with water means preparing a sample of the composition then immersing it into a scintillation vial filled with water for 5 minutes, followed by shaking the vial for approximately 30 seconds in a mechanical shaking device, and then emptying the contents of the vial through a standard 20 mesh screen.
  • Another embodiment of the present invention is a homogeneous polymer blend composition
  • a homogeneous polymer blend composition comprising from about 35 to about 45 weight percent graft modified biodegradable polymer and from about 65 to about 55 weight percent water-soluble polymer, wherein such composition is water disintegratable.
  • This composition is also characterized by a morphology of fine graft modified biodegradable polymer particles dispersed in a continuous phase of water-soluble polymer. The size of the modified biodegradable polymer domains is larger than those domains for the water-dispersible compositions.
  • water disintegratable as used herein, means that the composition will break into multiple pieces after
  • composition pieces 2 minutes and that some of the composition pieces will be caught by a 20 mesh screen.
  • One other embodiment of the present invention is a composition comprising from about 45 to about 55 weight percent graft modified biodegradable polymer and from about
  • water weakenable means that the composition remains in one piece but weakens and loses rigidity after 5 minutes and becomes drapeable; i.e., it bends without an external force applied to the composition when it is held by one corner at a horizontal position.
  • water stable means that the composition does not become drapeable and remains in one piece after testing with water.
  • a composition that is selectively water dispersible approximately 1-35% graft modified biodegradable polymer and approximately 65-99% water-soluble polymer are combined.
  • a composition that is selectively water- disintegratable approximately 35-45% graft modified biodegradable polymer and approximately 65-55% water- soluble polymer are combined.
  • a composition that is selectively water- weakenable approximately 45-55% graft modified biodegradable polymer and approximately 55-45% water-soluble polymer are combined.
  • a composition that is selectively water stable approximately 55- 99% graft modified biodegradable polymer and approximately 45-1% water-soluble polymer are combined.
  • Another embodiment of the present invention there is disclosed is a reactive polymer blend compositions of a grafted water-soluble polymer, such as grafted PEO or grafted PVOH, and a grafted biodegradable polymer, such as grafted PHBV, grafted poly(alkylene succinates), and grafted polycaprolactones.
  • the ratio of the grafted water-soluble polymer to the grafted biodegradable polymer in the blend of the present invention is between about 1 :99 and 99:1 by weight.
  • grafting monomers examples include the amounts of grafting monomer relative to the total weight of biodegradable polymers and the water-soluble polymer, the free radical initiators for the grafting reaction and the amount of free radical initiator for the grafting reaction are the same as described above for grafted polymers.
  • Processing characteristics of the polymer blends for films can be enhanced by the optional incorporation of lubricants or slip agents into the blends.
  • lubricants are well known in the art and include TWEEN 20 ® , TURGITOL ® NP 13 available from Union Carbide Corporation (Danbury, CT) and various fatty acids and fatty acid derivatives, such as KENAMIDE ® E available from Witco Chemical (USA).
  • the blends may contain other components to enhance the properties of the resulting material.
  • polyethylene glycol can be added to lower the melt viscosity of the melted blend to a range suitable for other processes, such as meltblown process or meltsprayed nonwoven-making process. Suitable polyethylene glycols are available from Union Carbide under the trade name CARBOWAX®.
  • Polymer blending is an important aspect of the manufacture of compositions of the present invention. Depending upon parameters, such as the selection of blending techniques, temperature profiles, and pressure applications, the final water responsive qualities of the compositions may be affected.
  • the extruder had two conical screws of 30 mm at the feed port and 20 mm at the die.
  • the screw length was 300 mm.
  • the PHBV resin (Biopol ® P600G from Zeneca Bio-Products) was fed to the feed port, the HEMA monomer and Lupersol ® 101 were both fed to the feed port by Eldex pumps.
  • the die used to extrude the modified PHBV strands had two openings of 3 mm in diameter which were separated by 5 mm.
  • the modified PHBV strands were cooled by a water bath.
  • PHBV Unlike polylactide ("PLA”), PHBV exhibited extremely slow solidification after initial cooling in water. In fact, the polymer strands could not even be cooled sufficiently in ice water ( ⁇ 0 C) quickly enough to be pelletized.
  • PHBV exhibited elastomeric properties in the melt.
  • the strands could easily be stretched and would retract to their initial length. This material property was not observed for grafted PLA or grafted polyolefins.
  • the grafted PHBV strands were extremely rigid and brittle. The solidification of both unmodified PHBV and grafted PHBV took several minutes to complete, so the polymer samples were collected in small chunks, allowed to solidify overnight, and were then chipped into small pieces.
  • the PHBV was fed into the extruder with a volumetric feeder at a throughput of 5.0 lb/hr.
  • the HEMA and the peroxide were injected into the extruder at throughputs of 0.25 lb/hr and 0.020 lb/hr, respectively.
  • the screw speed was 150 rpm.
  • Two grafted PHBV samples were produced on a
  • Table 1 shows the process conditions for the reactive extrusion of PHBV with HEMA on the Haake extruder.
  • Fig. 1 shows a chart of the torque versus time during the reactive extrusion.
  • the torque was observed to decrease significantly.
  • the HEMA grafted PHBV sample was collected.
  • the chemical pumps were stopped and the reactive extrusion was completed, the torque increased to about the level of torque before the reactive extrusion was started.
  • the observed changes in torque during the experiment indicated modification of the polymer and allowed for effective monitoring of the reactive extrusion process. No visible difference was observed between the extruded melt strands of unmodified PHBV and grafted PHBV.
  • Fig. 2 shows comparative proton NMR spectra for unmodified PHBV and for PHBV grafted with HEMA.
  • the characteristic peak for HEMA monomer (CH 3 ) was observed a 2.0 ppm. This confirmed the modification of PHBV, but did not quantify the amount of HEMA grafted on the PHBV.
  • melt rheology tests were performed at 180° C with a 30/1 (length diameter) mm/mm die.
  • the apparent melt viscosity was determined at apparent shear rates of 50, 100, 200, 500, 1000, and 2000 1/s.
  • Table 2 shows the data from differential scanning calorimetry ("DSC”) analysis of PHBV and HEMA grafted PHBV samples.
  • Fig. 4 shows a comparison between DSC curves for PHBV and HEMA grafted PHBV. Both curves show two characteristic melting peaks. The curves display the decrease in melting peaks and enthalpy of melting observed for HEMA grafted PHBV compared to unmodified PHBV. Besides the decrease in melting peaks, the two melting peaks were more separated for the grafted PHBV samples. In addition, the relative ratio of the high temperature melting peak to the low temperature melting peak was increased substantially after grafting, which showed that the properties of the two types of crystalline sizes were changed.
  • the reactive extrusion process for grafting PBS was carried out on both a Haake extruder as described in Example 1 and a ZSK-30 extruder with two different grades of PBS; i.e., Bionolle ® 1040 and Bionolle ® 1020.
  • the ZSK-30 extruder was a co-rotating, twin-screw extruder, manufactured by Werner & Pfleiderer Corporation of Ramsey, New Jersey.
  • the diameter of the extruder was 30 mm.
  • the length of the screws was 1388 mm.
  • This extruder had 14 barrels, numbered consecutively 1 to 14 from the feed hopper to the die.
  • the first barrel, barrel #1 received the PBS and was not heated but cooled by water.
  • the reactive extrusion of PBS differed significantly from the reactive extrusion of PLA, PHBV, or polyolefins. In fact, significant differences were observed between the reactive extrusions of the two different grades of PBS carried out on different extruders.
  • the reactive extrusion chemistry for PBS grafting is shown below:
  • Fig. 5 shows a chart of the torque versus time during a reactive extrusion of both PEG-MA grafted Bionolle ® 1040 samples.
  • the torque was observed to decrease significantly.
  • the reaction product was determined to have stabilized and the sample was collected.
  • the chemical pumps were stopped and the reactive extrusion was completed, the torque increased to the level prior to modification.
  • the same observations were made for the 8.9% PEG-MA and the 0.46% Lupersol ® 101 peroxide.
  • the PEG-MA grafted Bionolle ® 1040 samples appeared to have lower viscosity in the extruded melt strands. No visible gels were observed and the solid properties of the strands appeared to be similar to unmodified Bionolle ® 1040.
  • the extrusion conditions were then determined for the Bionolle ® 1020 reactive extrusion on the ZSK-30 extruder.
  • the unmodified Bionolle ® 1020 behaved similarly to unmodified Bionolle ® 1040 on the Haake extruder.
  • Four HEMA grafted Bionolle ® 1020 samples were produced on the ZSK-30 extruder.
  • the reactive extrusion experiments were designed to graft Bionolle ® 1020 with HEMA at low levels; z ' .e., approximately 3% and 5%. Additionally, the effects of peroxide addition were studied at constant HEMA addition levels. Table 4 below shows the reactive extrusion process conditions for HEMA grafted Bionolle ® 1020 experiments.
  • Reactive extrusion parameters such as time, temperature, % torque, and die pressure, were monitored on the ZSK-30 extruder during reactive extrusion of Bionolle ® 1020 with HEMA.
  • Table 5 shows the process conditions during the reactive extrusion of each of the HEMA grafted Bionolle ® 1020 samples.
  • the percent torque and melt temperature for each of the HEMA grafted Bionolle ® 1020 samples was equal to or greater that unmodified Bionolle ® 1020.
  • Fig. 7 displays the melt rheology curves for unmodified Bionolle ® 1040 and PEG-MA grafted Bionolle ® 1040 on the Haake extruder. The results show that the PEG ⁇
  • Fig. 8 displays the melt rheology curves for unmodified Bionolle ® 1020 and HEMA grafted Bionolle ® 1020 on the ZSK-30 extruder.
  • the melt rheology properties of the grafted material correlated with the observed reactive extrusion properties.
  • the 5% HEMA sample, at low relative peroxide level, showed a slight decrease in melt viscosity compared to unmodified Bionolle ® 1020.
  • Both of the 3% HEMA samples showed increased melt viscosity compared to unmodified Bionolle ® 1020.
  • the 3% HEMA samples also showed increased melt viscosity with increased peroxide addition levels, resulting from the crosslinking of the Bionolle ® 1020 polymer.
  • the 3% HEMA sample at 1.2% peroxide addition could not be collected, so no melt rheology data was collected.
  • Table 6 shows the data from DSC analysis of unmodified Bionolle ® 1040 and PEG-MA grafted Bionolle ® 1040 samples produced on the Haake extruder.
  • Table 7 shows the DSC data for unmodified Bionolle ® 1020 and HEMA grafted Bionolle ® 1020 samples produced on the ZSK-30 extruder.
  • the PEG-MA grafted Bionolle ® 1040 on the Haake extruder showed an increase in the melting peak compared to unmodified Bionolle ® 1040. This result was unexpected because, typically, grafted polymers have shown a decrease in melting peak upon grafting.
  • Fig. 9 shows a comparison between DSC curves for unmodified Bionolle ® 1040 and PEG-MA grafted Bionolle ® 1040.
  • the HEMA grafted Bionolle ® 1020 on the ZSK-30 extruder showed both a decrease in melting peak and the enthalpy of melting compared to unmodified Bionolle ® 1020.
  • Fig. 10 shows a comparison between DSC curves for ungrafted Bionolle ® 1020 and HEMA grafted Bionolle ® 1020.
  • the observed changes in thermal properties were an indication of modified crystalline structure and an indirect indication of HEMA grafting.
  • the observed decrease in melting peak and enthalpy of melting was more typical of grafted polymers, such as HEMA grafted PHBV or previous HEMA grafted polyester work.
  • This example shows the reactive extrusion procedure for making grafted PCL.
  • the same ZSK-30 twin screw extruder as in Example 2 above was used. Tone ® P-787 PCL was fed to the feed throat of the ZSK-30 twin screw extruder at a rate of 20 lbs/hr.
  • HEMA was fed to barrel #5 at a rate of 0.36 lbs/hr (1.8% by weight of PCL resin) and Lupersol ® 101 peroxide was fed to barrel #6 at a rate of 0.03 lbs/hr (0.15%) by weight of PCL resin).
  • the screw speed was 300 ⁇ m.
  • the melt temperature was 214° C.
  • the measured melt pressure was 422 psi.
  • the vacuum on the vent port (on barrel #11) was 24.49 inches Hg to remove unreacted HEMA monomer.
  • the resulting grafted PCL was cooled in a water bath, and pelletized into white colored pellets.
  • the grafted PCL strands were strong and ductile.
  • the surface of the strands and pellets were shiny.
  • the film casting of the grafted PCL was performed on the Haake twin screw extruder described in Example 1 fitted with an 8 -inch film die (by Haake). The film was cooled by a chill roll cooled by water at room temperature.
  • the extruder had four heating zones with temperatures set at 120° C, 130° C, 130° C, 140° C, respectively.
  • the screw speed was 40 ⁇ m.
  • the extruder was flood fed with the grafted PCL.
  • the measured melt temperature was 136 ° - 137° C.
  • the melt pressure was in the range from 800 to 1,100 psi.
  • Thin films of about 1.5 mil in thickness were obtained.
  • the film of grafted PCL was strong, shiny and ductile.
  • the film was clear and transparent.
  • the grafted PCL film had significantly improved film clarity compared to film made from unmodified PCL, which was opaque.
  • the grafted PCL melt was stickier than un-grafted PCL which indicated potential as an adhesive for hot melt uses.
  • Example 2 was used to make a series of blends of biodegradable polymer and a water-soluble polymer.
  • the first series of experiments used Bionolle ® 1020 PBS as the biodegradable polymer. PVOH was used as the water-soluble polymer.
  • PVOH Airfoil ® 203, by Air Products
  • the extruder temperatures were set at 1 10 ° C at zone 1 and 150° C at zones 2 and 3, 160° C at zone 4, 170 ° C at zone 5, and 180° C at zones 6 and 7.
  • the melt temperature was 199° C.
  • the melt pressure was 197 psi.
  • the screw speed was 300 ⁇ m.
  • the film produced was clear and water-soluble.
  • Example 6 Water Responsive Films of Biodegradable Polymer and a Water-Soluble Polymer The same procedure was followed as in Example 4 above, except that the PBS and PVOH were fed at a rate so as to produce a blend of 60% by weight PVOH and 40% by weight PBS.
  • the melt pressure was 202 psi.
  • the melt temperature was 197° C.
  • the extruded strands were smooth and well formed.
  • the strands of extruded polymer were then converted to pellets.
  • Example 7 Films Made From Blends Comprising
  • the pellets made in Examples 4 to 6 were made into films by a melt extrusion casting process using a Haake twin screw extruder, such as described in Example 1.
  • the extruder was set with temperatures for the four zones as follows: 170 ° C, 180° C, 180° C and 190 ° C.
  • the screw speed was 100 ⁇ m.
  • the films produced were 1 mil in thickness.
  • the films produced from the pellets of Example 4 were water-dispersible within 2 minutes in water at 22 C.
  • the films produced using the pellets of Example 5 were water- dispersible within 2 minutes in water at 22 C.
  • the films produced using the pellets of Example 6 were water-dispersible within 2 minutes in water at 22° C.
  • Example 2 above was used for the following example.
  • Two gravimetric feeders were used to feed two different polymers simultaneously to the feed throat of the extruder.
  • NS 70-4442 a water-soluble polymer from National Starch and Chemical Co., Bridgewater, NJ, having the designation NS 70-4442.
  • the 4442 is a water-soluble sulfonated polyester polymer.
  • the PCL was fed to the extruder at a feed rate of 16 lbs/hr; the NS 70- 4442 was fed at a rate of 4 lbs/hr.
  • the feed rates produced a ratio of PCL:NS 70-4442 of 80:20 by weight.
  • HEMA was injected to barrel #5 by an Eldex pump at a rate of approximately 0.4 lbs/hr.
  • Lupersol ® 101 was injected to barrel #6 at a rate of 0.032 lbs/hr by an Eldex pump.
  • the screw speed was 300 ⁇ m.
  • the temperatures were:
  • the melt temperature measured was 209° C.
  • the melt pressure was 258 psi.
  • the strands were cooled on a fan- cooled conveyor belt and subsequently were pelletized. The strands and pellets had smooth surfaces.
  • Cast films were made from the pellets on a Haake twin screw extruder as previously described.
  • the film showed water-sensitivity; i.e., reduced stiffness, increased deformability and softness.
  • the melt temperature was 210° C.
  • the melt pressure was 158 psi.
  • the films made from the blended composition were water-sensitive.
  • the water-sensitivity of the films may be improved by increasing the amount of NS 70- 4442 in the blend, thereby rendering the film water-dispersible or water-disintegratable.
  • Example 10 Polylactide (PLA) was supplied by Aldrich Chemical Company, Catalog # 43232-6.
  • Poly(butylene) succinate (PBS) was supplied by Showa Highpolymer Company under the name Bionolle ® 1020.
  • Polyvinyl alcohol (PVOH) was supplied by Nippon Gohsei under the trade name Ecomaty ® AX10000.
  • PLA grafted with 2-hydroxyethyl methacrylate was used.
  • the grafted PLA was produced, by reactive extrusion on a Werner & Pfleiderer ZSK-30 twin screw extruder. The procedure for making the grafted PLA is described in foregoing examples.
  • HEMA 2-Hydroxyethyl methacrylate
  • PEG-MA polyethylene glycol ethyl ether methacrylate
  • the peroxide initiator used was Lupersol ® 101, supplied by Atochem.
  • Blends were produced using a Rheomix ® 600 twin roller mixer (manufactured by Haake). The mixer had three heating zones, one each for the front plate, mixing chamber, and back plate. The temperatures for the zones, screw speed and mixing time were controlled by computer.
  • Haake mixer was performed as follows: The mixer was preheated to 180° C. A specified amount of PLA or grafted PLA and PVOH was added to the mixer and the material was mixed for five minutes at a screw speed of 150 ⁇ m. After five minutes, the melt was removed from the mixer and cooled in air.
  • Blends were also produced using a TW-100 screw extruder (manufactured by Haake) with three barrels and 300 mm processing length.
  • the unit contained a set of custom- made, counter-rotating, conical twin screws.
  • the feed section was not heated and was cooled with water.
  • the extruder had three heating section designated as Zone 1, Zone 2 and Zone 3 from the feeding section toward the die.
  • the die was designated as Zone 4.
  • the die had two openings of 3 mm diameter which were separated by 10 mm.
  • a typical polymer blending experiment on the Haake extruder was performed as follows: The heating zones were preheated to 170°, 180°, 180° C. The extruder was set at 150 ⁇ m. Pellets of PLA or grafted PLA were mixed at a specified ratio with pellets of PVOH. The mix of resin pellets was continuously cooled twice and pelletized twice.
  • a novel process for flushable and biodegradable polymer development was developed in which only one extrusion pass was employed. This process is called reactive blending.
  • a biodegradable polymer and a water-soluble polymer are blended while they are reactively grafted with the polar monomer.
  • the melt is extruded, cooled and pelletized.
  • the reactive blend has the potential to contain one or more of several unreacted and reacted products. Some portion of unreacted biodegradable and water-soluble polymer may remain in the final reactive blend. Grafted biodegradable and water-soluble polymers are possible reaction products in the reactive blend.
  • the reactive blend may contain some reactively connected biodegradable and water-soluble polymers, which would be novel compositions of matter.
  • the single-step, reactive blending process offers a number of advantages and benefits: 1) it is a lower cost process since only one extrusion, cooling and pelletizing cycle is required, ratherthan two; 2) it reduces polymer degradation because of one less extrusion pass; and 3) it causes less variation in the polymer blend composition and the quality of the resulting blends.
  • Reactive blending was carried out on the Haake
  • TW-100 twin screw extruder described above.
  • a typical reactive blending experiment on the Haake extruder was performed as follows: The heating zones were preheated to 160°, 180°, 180°, 190° C. The extruder was set at 150 ⁇ m. Pellets of PBS were mixed at a specified ratio with pellets of PEO. The mix of resin pellets was fed into the Haake extruder with a volumetric feeder at a throughput of 5 lb/hr. PEG-MA was added at the feeding section at 0.40 lb/hr and Lupersol ® 101 was added at the feeding section at 0.025 lb/hr. After adding PEG-MA and Lupersol ® 101 , the torque decreased and then stabilized. The process was allowed to reach equilibrium and the extruded strands were cooled in air and pelletized.
  • Reactive blends of PBS and PEO with PEG-MA were converted into thin films using the Haake extruder described above, except a 4-inch or 8-inch slit die was used instead of the two-strand die.
  • a chilled wind-up roll maintained at 15°-20° C was used to collect the film. Adjustments in die gap, screw speed and wind-up speed were used to optimize film processing and film thickness.
  • a typical film-converting run on the Haake extruder was performed as follows: the selected reactive blend pellets were flood feed into the feeding section. The temperature profile for the four heating zones was 170, 180°, 180° and 190° C. The melt temperature at the die was 195° C. The screw speed was 30 ⁇ m. The wind-up speed was 70% of maximum. The process conditions were adjusted to produce a film thickness of approximately 4 mils. The process was allowed to stabilize and the film was collected.
  • Dry tensile tests were performed on a Sintech 1/D tensile tester under the following conditions: gauge length- 30 mm, crosshead speed - 4 mm/s, narrow width of dogbone - 3.18 mm. Wet tensile tests were also carried out on the Sintech 1/D tensile tester under the same conditions, except the films were submerged underwater during testing. A water tank was used for wet tensile tests. Peak stress, percent strain-to-break, energy-to-break (area under stress versus strain curve), and modulus were calculated for each film test and the percent loss in tensile properties from dry to wet was determined.
  • DSC was performed on a TA Instruments DSC 2910. 10-15 mg of film sample was used for each test. The following method was followed for each test: 1 - equilibrate at -20° C, 2 - isothermal for 1 minute, 3 - ramp at 20° C/minute to 200° C, 4 - ramp at 30° C/minute to 30° C.
  • the reactive blends lost a greater percentage of tensile properties from dry to wet compared to the physical blends, which is very desirable for flushable applications.
  • the relative loss in tensile properties from dry to wet was obviously improved for the reactive blend film.
  • the physical and reactive blends of 40/60 PBS/PEO showed increased percent strain-to-break. Additionally, the physical blend of 30/70 PBS/PEO showed an increase in percent strain-to-break. In fact, when these blends were exposed to water, the films appeared to have somewhat elastomeric properties. These observations were quite su ⁇ rising, because similar blends of other polymer systems had always shown a decrease in tensile properties after the majority water-soluble component dissolved in water. Plasticization effects due to hydration of PEO, the unique "layered" mo ⁇ hology of PBS/PEO physical and reactive blends, and the interaction between PBS and PEO must have contributed to the unique wet tensile properties of these blends. The elastomeric properties of the reactive blends may even show the potential for development as a gasket for fit improvement, while remaining flushable.
  • Figures 11 and 12 show SEM (Scanning electron microscopy) images of the topological mo ⁇ hology of the fracture surface of 60/40 PBS/PEO physical and reactive blends films.
  • a two-phase microstructure was observed for the physical blend.
  • the adhesion between the PBS continuous phase and the PEO dispersed phase was quite poor, as shown by the presence of holes left by PEO particles which pulled away from the PBS at the interface of the two phases.
  • DSC differential scanning calorimetry
  • both the melting peaks (T m ) and the enthalpy of melting ( ⁇ H) were observed to decrease compared to the physical blends at the same weight ratios. Additionally, the melting peaks for the PEO phase of PBS/PEO reactive blends were observed to decrease with increased PEO content in the blends. The observed changes in thermal properties were an indication of modified crystalline structure and an indirect indication of grafting.
  • Fig. 15 shows the observed decrease in T m for the PEO phase of the PBS/PEO reactive blends as percent PEO in the blends was increased.
  • Figure 16 shows an increase in change of T m ( ⁇ T m ) for the PEO phase of the reactive blends compared to physical blends as the percent PEO in the blends was increased.
  • Fig. 17 displays a comparison between the DSC curves for 30/70 PBS/PEO physical and reactive blends. Both curves show two characteristic melting peaks, the first for PEO and the second for PBS. The curves display the decrease in T m and ⁇ H for the PEO and PBS components.
  • Melt rheology was studied for PBS/PEO physical and reactive blends on a Goettfert capillary rheometer at 195° C using the following procedure. Melt rheology tests were performed on a Goettfert Rheograph 2003 with a 30/1 mm L/D die at 195° C (the observed melt temperature for most film- converting runs). The apparent melt viscosity for each material was determined at apparent shear rates of 50, 100, 200, 500, 1000, 2000 s '1 . A rheology curve was plotted for each material of apparent viscosity versus apparent shear rate.
  • Figure 18 displays the melt rheology curves 20/80 and 60/40 PBS/PEO physical and reactive blends, as well as the melt rheology curve for PBS alone.
  • the results showed that the physical blends, over the entire range of shear rates, had higher melt viscosity than the reactive blends. Additionally, with greater amounts of PBS, the melt viscosity was reduced in both the physical and reactive blends. The observed decrease in melt viscosity of the reactive blends was expected to be due to lubrication effects of grafted and unreacted PEG-MA , as well as the reduction of molecular weight and improved compatibility due to reactive blending.
  • Example 11 As shown in Example 1, the grafting of PHBV with HEMA by a continuous reactive extrusion process is not practical because the grafted PHBV does not solidify or crystallize at a sufficient rate. The following example shows how the grafted PHBV can be modified so that it can be produced by a continuous reactive extrusion process.
  • Example 2 The same Haake counter-rotating, twin-screw extruder was used as in Example 1. The four temperature zones were set at 170°, 200°, 190° and 190° C, respectively. The screw speed was 150 ⁇ m. A mixture of PLA and PHBV in a weight ratio of 1 : 1 were fed into the extruder with a volumetric feeder at a throughput of 5.0 lb/hr. The PHBV was the same as used in Example 1. The PLA was purchased from
  • the PLA was a biodegradable polymer and had a number average molecular weight of approximately 60,000 g/mo. And a weight average molecular weight of approximately 144,000 g/mol.
  • HEMA monomer and Lupersol ®
  • Example 101 were injected into the extruder at throughputs of 0.5 lb/hr and 0.025 lb/hr, respectively.
  • the HEMA and Lupersol ® 101 were the same as used in Example 1.
  • the extruded strands solidified quickly and were easily directly pelletized.
  • Example 11 The same procedure and extrusion conditions were used as in Example 11, except the feeding rate of the polymer mixture was increased to 8.7 lb/hr. Even at this high extrusion rate, the extruded strands quickly solidified and were easily directly pelletized.
  • Example 13 The same procedure and extrusion conditions were used as in Example 12, except butyl acrylate was substituted for HEMA. The butyl acrylate was fed at a rate of 0.86 lb/hr and the Lupersol ® 101 was fed at a rate of 0.044 lb/hr. The extruded strands quickly solidified and were easily directly pelletized.
  • Example 14 The same procedure was followed as in Example 11, except the temperature zones were set at 170°, 180°, 180° and 190° C, respectively. Furthermore, PEO was substituted for the PLA. A mixture of PEO and PHBV in a weight ratio of
  • Example 10 50:50 were fed into the extruder with a volumetric feeder at a throughput of 5.0 lb/hr.
  • the PEO was the same as used in Example 10.
  • HEMA monomer and Lupersol ® 101 were injected into the extruder at throughputs of 0.5 lb/hr and 0.025 lb/hr, respectively.
  • the extruded strands solidified quickly and were easily directly pelletized.
  • Example 15 The same procedure was followed as in Example 14, except PEG-MA was substituted for HEMA. The extruded strands solidified quickly and were easily directly pelletized.

Abstract

La présente invention concerne un polymère biodégradable hydrolytiquement modifié ainsi qu'un procédé de préparation d'un polymère biodégradable hydrolytiquement modifiable. Dans un mode de réalisation préféré, l'invention concerne un procédé de greffage de groupes polaires sur des polymères biodégradables, ainsi que des compositions polymériques biodégradables modifiées produites selon ce procédé. Ces compositions polymériques sont utiles comme composants dans des articles jetables dans les toilettes et dégradables. L'invention se rapporte en outre à des mélanges polymériques sensibles à l'eau ainsi qu'à un procédé de préparation de ces mélanges polymériques.
PCT/US2001/047494 2000-12-29 2001-12-13 Compositions polymeriques biodegradables sensibles a l'eau et leur procede de preparation WO2002053640A1 (fr)

Priority Applications (5)

Application Number Priority Date Filing Date Title
MXPA03005806A MXPA03005806A (es) 2000-12-29 2001-12-13 Composiciones de polimero biodegradables que responden al agua y metodo para hacer las mismas.
DE10197119T DE10197119T5 (de) 2000-12-29 2001-12-13 Auf Wasser reagierende, biologisch abbaubare Polymerzusammensetzungen und Verfahren zu deren Herstellung
GB0313501A GB2387388B (en) 2000-12-29 2001-12-13 Water-responsive biodegradable polymer blends
KR10-2003-7008726A KR20030068567A (ko) 2000-12-29 2001-12-13 수 반응성 생분해성 중합체 조성물 및 그의 제조 방법
BR0116614-0A BR0116614A (pt) 2000-12-29 2001-12-13 Composições de polìmero biodegradáveis de resposta à água e método de fabricação das mesmas

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US75307700A 2000-12-29 2000-12-29
US09/753,077 2000-12-29

Publications (1)

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WO2002053640A1 true WO2002053640A1 (fr) 2002-07-11

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KR (1) KR20030068567A (fr)
BR (1) BR0116614A (fr)
DE (1) DE10197119T5 (fr)
GB (1) GB2387388B (fr)
MX (1) MXPA03005806A (fr)
WO (1) WO2002053640A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011156878A1 (fr) * 2010-06-14 2011-12-22 Fatima Aparecida Do Amaral Couche-culotte jetable biodégradable (écologique)
WO2021028918A1 (fr) 2019-08-12 2021-02-18 Solutum Technologies Ltd Composites et leurs utilisations

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997047670A1 (fr) * 1996-06-13 1997-12-18 Regents Of The University Of Minnesota Procede permettant de greffer des groupes fonctionnels a des polymeres synthetiques pour fabriquer des plastiques biodegradables
WO1999006456A1 (fr) * 1997-07-31 1999-02-11 Kimberly-Clark Worldwide, Inc. Compositions de polylactide modifiees, films et fibres biodegradables et reagissant a l'eau comprenant un polylactide et un poly(alcool) de vinyle, et leurs procedes de preparation
US5952433A (en) * 1997-07-31 1999-09-14 Kimberly-Clark Worldwide, Inc. Modified polyactide compositions and a reactive-extrusion process to make the same

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1997047670A1 (fr) * 1996-06-13 1997-12-18 Regents Of The University Of Minnesota Procede permettant de greffer des groupes fonctionnels a des polymeres synthetiques pour fabriquer des plastiques biodegradables
WO1999006456A1 (fr) * 1997-07-31 1999-02-11 Kimberly-Clark Worldwide, Inc. Compositions de polylactide modifiees, films et fibres biodegradables et reagissant a l'eau comprenant un polylactide et un poly(alcool) de vinyle, et leurs procedes de preparation
US5952433A (en) * 1997-07-31 1999-09-14 Kimberly-Clark Worldwide, Inc. Modified polyactide compositions and a reactive-extrusion process to make the same

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011156878A1 (fr) * 2010-06-14 2011-12-22 Fatima Aparecida Do Amaral Couche-culotte jetable biodégradable (écologique)
WO2021028918A1 (fr) 2019-08-12 2021-02-18 Solutum Technologies Ltd Composites et leurs utilisations

Also Published As

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GB2387388A (en) 2003-10-15
GB0313501D0 (en) 2003-07-16
BR0116614A (pt) 2004-09-28
MXPA03005806A (es) 2005-02-14
KR20030068567A (ko) 2003-08-21
GB2387388B (en) 2005-03-23
DE10197119T5 (de) 2004-04-15

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