MXPA01006365A

MXPA01006365A - Biodegradable pha copolymers

Info

Publication number: MXPA01006365A
Application number: MXPA/A/2001/006365A
Authority: MX
Inventors: Noda Isao
Original assignee: The Procter & Gamble Company
Priority date: 1998-12-21
Filing date: 2001-06-21
Publication date: 2001-12-13

Abstract

The present invention relates to biodegradable PHA copolymers comprising at least two randomly repeating monomer units. The present invention further relates to a plastic article comprising a biodegradable copolymer, wherein the biodegradable copolymer comprises at least two randomly repeating monomer units (RRMU) wherein the first RRMU has the structure wherein R1 is H, or C1 or C2 alkyl, and n is 1 or 2;the second RRMU has the structure and wherein at least 50%of the RRMUs have the structure of the first RRMU. The present invention further relates to an absorbent article comprising a liquid pervious topsheet, a liquid impervious backsheet comprising a film comprising a PHA of the present invention and an absorbent core positioned between the topsheet and the backsheet.

Description

COPOLYMERS OF PHA BIODEGRADABLES FIELD OF THE INVENTION The present invention relates to biodegradable PHA copolymers and to plastic articles comprising these biodegradable PHA copolymers.

BACKGROUND OF THE INVENTION Polymers have uses in a variety of plastic articles including films, sheets, fibers, foams, molded articles, adhesives and many other specialty products. For applications in the areas of packaging, agriculture, household goods and personal care products, polymers normally have a short use cycle (less than 12 months). For example, in food packaging, polymers perform the function of a protective agent and are quickly discarded after consuming the content. Household products such as detergent bottles and disposable diapers are discarded immediately after the product is used. Most of this plastic material ends up in the stream of solid waste and is directed to some sanitary landfill space, which is increasingly scarce and more expensive. While some efforts have been made to recycle them, the nature of the polymers and the way they are produced and converted into products limit the number of possible applications in recycling. The repeated processing of pure and uniform polymers results in degradation of the material and, consequently, poor mechanical properties. The different qualities of chemically similar plastics (for example, polyethylenes of different molecular weights, such as those used in milk containers and bags of self-service stores) that are mixed when collected can cause problems in the processing of the recovered material making it of quality inferior or unusable. The applications of absorbent articles such as diapers, sanitary napkins, pantiliners and the like, involve several different types of plastics. In these cases, recycling is particularly expensive, due to the difficulty of separating the different components. Disposable products of this type generally comprise some kind of fluid permeable material on the upper canvas, an absorbent core, and a fluid impervious material on the reinforcing canvas. Heretofore, said absorbent structures have been prepared using, for example, upper canvas materials prepared from woven polypropylene or nonwoven polypropylene or porous preformed film materials. The materials for the reinforcing sheet typically comprise flexible polyethylene sheets. The absorbent core materials typically comprise wood pulp fibers or wood pulp fibers combined with absorbent gelling materials. Although these products comprise a large amount of materials that would be expected to be degraded "in the end and although these products contribute only a very small percentage of the total solid waste generated by consumers each year, there is nevertheless a need perceived to design these disposable products from materials that are susceptible to becoming compost A conventional disposable absorbent product is already susceptible to being largely composted A typical disposable diaper, for example, consists of approximately 80% susceptible materials from composting, for example, wood pulp fibers and the like In the composting process, disposable absorbent articles already used are comminuted and mixed with organic waste before their conversion into compost per se. has completed the transformation into compost, the particles not susceptible ible to be transformed into compost are removed by sieving. In this way, even today's absorbent articles can be processed successfully in commercial compost processing plants. However, there is a need to reduce the amount of materials not susceptible to becoming compost present in the disposable absorbent articles. There is a particular need to replace the polyethylene reinforcement canvases of the absorbent articles with films of material susceptible to becoming compost, impervious to liquids, because the reinforcing canvas is typically one of the largest components, not susceptible to transformation in compost, of a conventional disposable absorbent article. In addition to being susceptible to composting, films used as reinforcement canvases in absorbent articles must satisfy many other performance requirements. For example, the resins must be thermoplastic in such a way that conventional methods of film processing can be employed. These methods include the extrusion of film by casting and blowing of single layer structures as well as the coextrusion of film by casting or by blowing multilayer structures. Other methods include the extrusion coating of a material by one or both P1298 sides of a substrate capable of being transformed into compost, such as another film, a non-woven fabric or a continuous strip of paper. However, other properties are essential in the operations to convert the product where the films are used to manufacture absorbent articles. The properties, such as tensile strength, tensile modulus, tear strength and thermal softening point, greatly determine how well a film will work in the converter lines. In addition to the mentioned properties, additional additional properties are needed to meet the requirements of the end user of the absorbent article. The properties of the film such as impact resistance, puncture resistance, and moisture transmission are important, because they influence the durability and containment of the absorbent article while in use. Once the absorbent article is discarded and enters the composting process, other properties become important. Regardless of whether the incoming waste is pre-shredded or not, it is important that the film or large fragments of the film undergo initial fragmentation to become much smaller particles during the initial phases P1298 of the transformation into compost. Otherwise, the films or large fragments can be removed from the composting stream by sifting and would never be part of the final compost. In the past, the biodegradability and physical properties of a variety of polyhydroxyalkanoates (PHAs) have been studied. Polyhydroxyalkanoates are polyester compounds produced by a variety of microorganisms, such as bacteria and algae. While polyhydroxyalkanoates have been of general interest due to their biodegradable nature, their effective use as plastic material has been hampered by their thermal instability. For example, poly-3-hydroxybutyrate (PHB) is a natural product of bacteria and algae, which stores energy, and which is present in discrete granules within the cytoplasm of the cell. However, unlike other biologically synthesized polymers, such as proteins and polysaccharides, PHB is thermoplastic and has a high degree of crystallinity and a well-defined melting temperature of about 180 ° C. Unfortunately, PHB becomes unstable and degrades at elevated temperatures close to its melting temperature. Due to this thermal instability, commercial applications for the PHB have been extremely P1298 limited. As a result, some researchers have studied other polyhydroxyalkanoates, such as poly (3-hydroxybutyrate-co-3-hydroxyvalant) (PHBV), in the hope of discovering a polyhydroxyalkanoate that has sufficient thermal stability as well as other chemical and physical properties suitable for its use in practical applications. Unfortunately, polyhydroxyalkanoates such as PHB and PHBV are difficult to process to make suitable films in reinforcing canvas applications. As previously mentioned, the thermal instability of the PHB makes this processing almost impossible. In addition, the slow rates of crystallization and flow properties of PHB and PHBV make processing difficult for the film. In the United States Patent 4,393,167, by Holmes et al., Issued July 12, 1983 and in United States Patent 4,880,592, issued November 14, 1989, examples of homopolymers of PHB and copolymers of PHBV. PHBV copolymers are commercially available from Imperial Chemical Industries under the trade name BIOPOL. PHBV copolymers are currently produced with valeriato contents ranging from about 5 to about 24 mol%. An increase in the valeriato content decreases the melting temperature, crystallinity and polymer stiffness. A global appreciation of the BIOPOL technology is provided in BUSINESS 2000+ (Winter, 1990). Due to the slow rate of crystallization, a film made from PHBV will adhere to itself after cooling; an important fraction of PHBV remains amorphous and sticky for long periods of time. In film casting operations, where the film is immediately cooled in cooling rolls after it leaves the film die, the molten PHBV often adheres to the rolls, restricting the speed at which the film can be processed, or even preventing the collection of the film. In blown films, the residual adhesion of PHBV causes the tubular film to adhere to itself after it has cooled and collapsed to be rolled. U.S. Patent 4,880,592, to Martini et al., Issued November 14, 1989, discloses the means to obtain a PHBV monolayer film for diaper reinforcement canvas applications, by coextruding the PHBV between two polymer layers of sacrifice, for example, a polyolefin, stretching and orienting the multilayer film and subsequently peeling off the polyolefin layers after the PHBV has had time to crystallize. The remaining PHBV film is then laminated, either to water soluble films or to water insoluble films, such as polyvinylidene chloride or other polyolefins. Unfortunately, these drastic and cumbersome processing measures are necessary in an effort to avoid the inherent difficulties associated with PHBV processing to produce films. Based on the above, there is a need for plastic articles that can biodegrade. In effect, these biodegradable articles would facilitate the "recycling" of plastic articles to obtain another usable product, such as a soil improver, through its transformation into compost. To meet this need, there is a preliminary need for a biodegradable polymer that has the ability to be easily processed into a plastic article that can be used in disposable products.

OBJECTIVES OF THE INVENTION It is an object of the present invention to provide a biodegradable polyhydroxyalkanoate copolymer (PHA). It is also an object of the present invention to provide plastic articles that include a biodegradable polyhydroxyalkanoate (PHA). It is also an object of the present invention to provide a method for using a biodegradable polyhydroxyalkanoate (PHA) for the manufacture of plastic articles. It is also an object of the present invention to provide a disposable sanitary garment that includes a film containing a biodegradable polyhydroxyalkanoate (PHA).

SUMMARY OF THE INVENTION The present invention relates to novel biodegradable polyhydroxyalkanoate (PHA) copolymers that includes at least two monomer units that are randomly repeated. The present invention, additionally, relates to plastic articles that include a biodegradable copolymer, wherein the copolymer includes at least two randomly repeating monomer units in which the first monomeric unit has the structure wherein R1 is H, or C1 or C2 alkyl, and n is 1 or 2; the second monomeric unit has the structure and where at least 50% of the monomeric units randomly repeated have the structure of the first monomeric unit. These plastic articles include films, sheets, fibers, foams, molded articles, non-woven fabrics, elastomers and adhesives. The present invention additionally relates to an absorbent article comprising a liquid permeable top sheet, a biodegradable liquid impervious reinforcing sheet comprising a film that includes a biodegradable PHA, and an absorbent core placed between the top canvas and the reinforcement.

DETAILED DESCRIPTION OF THE INVENTION The present invention responds to the need for a biodegradable copolymer that has the ability to be easily processed to make a plastic article. The present invention additionally responds to the need for disposable plastic articles with improved biodegradability and / or susceptibility to be transformed into compost. As used herein, "ASTM" means American Society for Testing and Materials. As used herein, "comprising or including" means that other steps and other ingredients may be added that do not affect the final result. This term encompasses the terms "consisting of" and "consisting essentially of". As used herein, "alkyl" refers to a saturated chain containing carbon that may be straight or branched; and substituted (mono- or poly-) or unsubstituted. As used herein, "alkenyl" refers to a carbon containing chain that can be monounsaturated (ie, a double bond in the chain) or polyunsaturated (ie, two or more double bonds in the chain); straight or branched; and substituted (mono- or poly-) or unsubstituted. As used herein, "PHA" refers to a polyhydroxyalkanoate of the present invention. As used herein, "PHB" refers to the poly- (3-hydroxybutyrate) homopolymer. As used herein, "PHBV" refers to the poly (3-hydroxybutyrate-co-3-hydroxyvalant) copolymer. As used herein, "PHBMV" refers to the poly (3-hydroxybutyrate-co-3-hydroxy-4-methylvaleriato) copolymer. As used here, "biodegradable" refers to the ability of a compound to be finally degraded P1298 completely in C0 and water or biomass by microorganisms and / or natural environmental factors. As used herein, "susceptible to transformation into compost" refers to a material that meets the following three requirements: (1) the material has the ability to be processed in a plant for the production of solid waste compost; (2) if it is processed, the material will be part of the final compost; and (3) if the compost is used on land, the material will eventually biodegrade on the land. For example, a polymeric film material, present in the solid waste sent to a plant for the production of compost to be processed, does not necessarily end in the final compost. Certain compost plants subject the solid waste stream to an air classification before starting the process in order to separate the paper and other materials. A polymer film would most likely be separated from the solid waste stream in this air classification, and therefore would not be processed in the plant. However, it can still be a material "susceptible of being transformed into compost" according to the previous definition, because "it has the capacity" to be processed in a plant for the elaboration of compost.

The requirement that the material forms part of the final compost, usually refers to the fact that it undergoes a form of degradation in the process of transformation into compost. Typically, the solid waste stream will be subjected to a comminution step at an early stage of the compost transformation process. As a result, the polymer film will be present as shreds instead of a sheet. In the final stage of the process of composting, the final compost will be subjected to a sieving step. Normally, the shreds of the polymer will not pass through the meshes if they have retained the size they had immediately after the shredding step. The materials capable of being transformed into compost of the present invention will have lost such part of their integrity during the process of composting as to allow the partially degraded shreds to pass through the screen meshes. However, it is conceivable that a compost production plant would subject the solid waste stream to a very rigorous shredding and a fairly thick screening, in which case the non-degradable polymers such as polyethylene would meet the requirement (2). Therefore, meeting requirement (2) is not sufficient for a material to be susceptible of being transformed into compost within the framework of the present definition.

P1298 What distinguishes material that can be transformed into compost, as defined here, from a material such as polyethylene is the requirement (3), that the material finally biodegrades in Earth. This requirement of biodegradability is not essential to the process of transformation into compost or to the use of compost on land. Solid waste and compost resulting from this process may contain non-biodegradable materials of all types, for example, sand. However, to avoid the accumulation of artificial materials in the earth, it is required, within this frame of reference, that these materials be completely biodegradable. For the same reason, it is by no means absolutely necessary for this biodegradation to be rapid. While the material itself and the intermediate decomposition products are not toxic or otherwise harmful to the soil or crops, it is entirely acceptable that their biodegradation requires several months or even years, since this requirement is present only for the purpose of avoiding the accumulation of artificial materials in the earth. All copolymer composition ratios mentioned herein refer to molar ratios, unless specifically indicated otherwise. The present invention relates to P1298 biodegradable copolymers which are surprisingly easy to transform into plastic articles, particularly in films, as compared to PHB homopolymer and PHBV copolymer. As used herein, "plastic article" refers to a copolymer transformed into a film, sheet, fiber, foam, molded article, non-woven fabric, elastomer or adhesive. PHAs useful for transforming into the plastic articles of the present invention include at least two randomly repeating monomer units (RRMUs). The first RRMU has the structure where R1 is H, or C1 or C2 alkyl and n is 1 or 2. The second RRMU has the structure In one embodiment of the present invention, at least about 50%, but less than 100%, of the P1298 RRMU have the structure of the first RRMU; more preferably at least about 60%, more preferably at least about 70%; more preferably at least about 80% and even more preferably at least about 90%. When a PHA of the present invention is transformed into a film, sheet, or soft elastic fiber, preferably from about 50% to about 99.9% of the RRMU have the structure of the first RRMU; more preferably from about 75% to about 99%; more preferably still from about 85% to about 98%; and most preferably from 85% to about 95%. When a PHA of the present invention is transformed into a normal fiber or a molded article (eg, injection or blow molded) preferably from about 80% to about 99.5% of the first RRMU have the structure of the first RRMU; more preferably from about 90% to about 99.5%; even more preferably from about 95% to about 99.5%. When a PHA of the present invention is transformed into an elastomer or an adhesive, preferably from about 50% to 85% of the RRMU have the structure of the first RRMU.

P1298 When a PHA of the present invention is transformed into a nonwoven, preferably from about 85% to about 99.5% of the RRMUs have the structure of the first RRMU, more preferably from about 90% to about 99.5%; even more preferably from about 95% to about 99.5%. In one embodiment of the present invention, R1 is an alkyl Ci and n is 1, such that they form the repeating monomeric unit 3-hydroxybutyrate. In another embodiment of the present invention, R1 is a C2 alkyl and n is 1, such that they form the repeating monomeric unit 3 -hydroxyvalate. In another embodiment of the present invention, R1 is H and n is 2, such that they form the repeating monomeric unit 4-hydroxybutyrate. In another embodiment of the present invention, R1 is H and n is 1, such that they form the repeating monomeric unit 3-hydroxypropionate. In another embodiment, the copolymer useful in the present invention includes one or more additional RRMUs having the structure P1298 where R3 is H, or an alkyl or alkenyl Ci, C2, C3, C4, C5, Ce, C, Cs, C9, Cio, CU, C12, C13, C? , C15, Cig, C ± -j, Cig or C19; and m is 1 or 2 and, where, the additional RRMUs are not equal to the first RRMU or the second RRMU. Preferably the copolymer includes 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or more different RRMU. In a preferred embodiment of the present invention, R3 is an alkyl or alkenyl Ci, C2, C3, C4, C5, g C7, Cs, C9, Cio, CU, C? 2, C? 3, C14, C15, Cis, C? 7, C? 8 or C? 9; and m is 1. In a preferred embodiment of the present invention, R3 is an alkyl Ci and m is 1, such that they form the repeating monomeric unit 3-hydroxybutyrate. In another embodiment of the present invention, R3 is a C2 alkyl and m is 1, such that they form the repeating monomeric unit 3-hydroxyvaleriate. In another embodiment of the present invention, R3 is H and m is 2, such that they form the monomeric repeating unit 4-hydroxybutyrate. In another embodiment of the present invention, R3 is P1298 H and m is 1, such that they form the repeating monomeric unit 3-hydroxypropionate. Preferably, the novel biodegradable PHAs of the present invention that include two RRMUs have a first RRMU having the structure wherein R1 is H or a Ci or C2 alkyl and n is 1 or 2; and a second RRMU that has the structure where at least 50% of the RRMU have the structure of the first RRMU. Preferably, the novel biodegradable PHAs of the present invention that include three RRMUs have a first RRMU having the structure where R1 is H, or Ci or C2 alkyl or alkenyl, and n is 1 or 2; P1298 a second RRMU with the structure and a third RRMU with the structure where R3 is H, or an alkyl or alkenyl Ci, C2, C3, C4, C5, Cß C7, Cs, C9, Cio / Cu, C12, C13, C14, C15, Ci6, C17, Cis or C19; and m is 1 or 2; where at least 50% of the RRMU have the structure of the first RRMU; and where the third RRMU is not equal to the first monomeric unit that is randomly repeated or to the second monomeric unit that is randomly repeated.

Synthesis of Biodegradable PHAs The biodegradable PHAs of the present invention can be synthesized by chemical methods or by biological based methods. The chemical route involves the ring-opening polymerization of ß-lactone monomers as described below. The catalysts or initiators used can be a variety of materials P1298 such as aluminoxanes, diestanoxanes or alkoxy-zinc and alkoxy-aluminum compounds (see Agostini, DE, JB Lando, and JR Shelton, J. POLYM, Sci. PART Al, Vol. 9, pp. 2775-2787 (1971); Gross, RA, Y. Zhang, G. Konrad, and RW Lenz, MACROMOLECULES, Vol. 21, pp. 2657-2668 (1988), and Dubois, P., 1. Barakat, R. Jérdme, and P. Teyssié , MACROMOLECULES, Vol. 26, pp. 4407-4412 (1993), Le Borgne, A. and N. Spassky, POLYMER, Vol. 30, pp. 2312-2319 (1989); Tanahashi, N., and Y. Doi, MACROMOLECULES, Vol. 24, pp. 5732-5733 (1991); Hori, Y., M. Suzuki, Y. Takahashi, A. Ymaguchi, and T. Nishishita, MACROMOLECULES, Vol. 26, pp. 4388-4390 (1993); and Kemnitzer, J.E., S.P. McCarthy, and R.A. Gross, MACROMOLECULES, Vol. 26, pp. 1221-1229 (1993). The production of an isotactic polymer can be achieved by the polymerization of an enantiomerically pure monomer and a non-racemizing initiator, with retention or inversion of the stereocenter configuration, or by the polymerization of a racemic monomer with an initiator that preferably polymerizes an enantiomer. For example: - PHBMV Random Copolymer P1298 Naturally derived PHAs of the present invention are isotactic and have the absolute configuration R at the stereocenters of the polymer backbone. Alternatively, isotactic polymers can be prepared where the configuration of the stereocenters is predominantly S. Both isotactic materials will have the same physical properties and most of the same chemical reactivities, except when a stereospecific reagent, such as an enzyme, is involved. Atactic polymers, polymers with random incorporation of stereocenters R and S, can be produced from the racemic monomers and initiators or polymerization catalysts that show no preference for any enantiomer, while these initiators or catalysts (eg. distannoxane catalysts) frequently polymerize high-grade monomers of optical purity in isotactic polymer (see Hori, Y., M. Suzuki, Y. Takahashi, A. Yamaguchi, T. Nishishita, MACROMOLECULES, Vol. 26, pp., 5533- 5534 (1993)). Alternatively, the isotactic polymer can be produced from racemic monomers if the polymerization catalyst has an improved reactivity with one enantiomer than with another. Depending on the degree of preference, stereohomopolymers R can be produced P1298 or S separated, the stereoblock copolymers or a mixture of stereoblock copolymers and stereo homopolymers. (See Le Borgne, A. and N. Spassky, N., POLYMER, Vol. 30, pp. 2312-2319 (1989); Tanahashi, N., and Y. Doi, MACROMOLECULES, Vol. 24, pp. 5732 -5733 (1991) and Benvenuti, M. and RW Lenz, J. POLYM, SCI .: PART A: POLYM, CHEM., Vol. 29, pp. 793-805 (1991)). It is known that some initiators or catalysts produce predominantly syndiotactic polymers, polymers with R and S stereorecentric repeat units alternating, from racemic monomers (see Kemnitzer, JE, SP McCarthy and RA Gross, MACROMOLECULES, Vol. 26, pp. 1221- 1229 (1993)), while some initiators or catalysts can produce all three types of stereopolymers (see Hocking, PJ and RH Marchessault, POLYM BULL., Vol. 30, pp. 163-170 (1993)). For example, the preparation of the copolymer poly (3-hydroxybutyrate-co-3-hydroxyalkanoate) in which the comonomer 3-hydroxyalkanoate is a 3-alkyl-β-propiolactone, wherein the alkyl group contains at least three (3) carbons , it can be done in the following way. Appropriate precautions are taken to exclude air and moisture. The lactone monomers (purified, dried and stored in an inert atmosphere) ß-butyrolactone and 3-alkyl-β-propiolactone, in the desired molar ratio, are P1298 loaded by means of a syringe or cannula into an oven-dried borosilicate glass tube or flask, purged with argon and flamed, covered with a rubber membrane. The polymerization catalyst is added as a solution of toluene, by means of a syringe. The tube is vortexed, carefully, to mix the reagents (but should not touch the rubber membrane) and then heated in an oil bath at the desired temperature for the prescribed time. As the reaction progresses, the mixture becomes viscous and can solidify. If an isotactic polymer is produced, the solid polymer precipitates until the entire mass solidifies. The product can then be cooled, removed from the tube and separated from the residual monomer by vacuum drying. Alternatively, the product can be dissolved in an appropriate solvent (for example, chloroform) and recovered by precipitation in a non-solvent medium (for example, a 3: 1 v / v ether-hexane mixture) and dried under vacuum. Molecular weight is determined by standard methods, such as size exclusion chromatography (CET, also known as gel infiltration chromatography, or CIG). The comonomer content of the polymers is determined by means of nuclear magnetic resonance (NMR). In a preferred method for the synthesis of P1298 PHA of the present invention, an alkyloxyzinc alkoxide is used as the initiator, as set forth in U.S. Patent No. 5,648,452, entitled "Polymerization of Beta-Substitued-Beta-Propiolactones Initiated by Alkylzinc Alkoxides", L.A. Schechtman and J.J. Kemper, assigned to Procter and Gamble Company, issued July 13, 1997. These initiators have the general formula R1ZnOR2, where R1 and R2 are independently a C? -C? 0 alkyl. In a preferred method of synthesis, the initiator is selected from the group consisting of ethylzinc isopropoxide, methylzinc isopropoxide, ethylzinc ethoxide or ethylzinc methoxide; more preferably ethyzinc isopropoxide. Another copolymer useful in the present invention can be made by replacing the initiator materials (monomers), of the above process, with 3-alkyl-β-lactones corresponding to the desired monomer units in the final copolymer product. Alternatively, the biological synthesis of the biodegradable PHAs, useful in the present invention, can be carried out through fermentation with the appropriate organism (naturally or genetically modified) with an appropriate feed (single or multicomponent). The biological synthesis can also be carried out with botanical species genetically modified to express P1298 copolymers of interest (see World Patent Application No. 93-02187, by Somerville, Poirier and Dennis, published February 4, 1993; and U.S. Patent No. 5,650,555, Dennis et al., issued July 22, 1997, and U.S. Patent No. 5,610,041, Nawrath et al., issued March 11, 1997, and Poole, R., SCIENCE, Vol. 245, pp. 1187-1189 ( 1989)).

Crystallinity The percent volume of crystallinity (Fc) of a semi-crystalline polymer (or copolymer) often determines the type of end-use properties that the polymer has. For example, highly crystalline (greater than 50%) polyethylene polymers are strong and rigid and are suitable for products such as plastic milk containers. On the other hand, low crystallinity polyethylene is flexible and hard and is suitable for products such as food wraps and garbage bags. The crystallinity can be determined in several ways, including x-ray diffraction, differential scanning calorimetry (DAS), density and infrared absorption measurements. The most convenient method depends on the material to be tested. X-ray diffraction is best suited when little is known about thermal properties P1298 of the material and when changes in the crystal structure may occur. The basic principle depends on the fact that the amorphous parts of the material scatter the x-rays in a wide or diffuse range of angles, while the crystals diffract the x-rays at well-defined acute angles. However, the total dispersed intensity is constant. This allows the amount of crystalline material in a sample to be calculated if the diffraction intensities of the amorphous part and the crystalline part can be separated. Ruland has developed a very precise method that can detect differences in percentage crystallinity as small as 2% (see Vonk, C., FJ Balta - Calleja, X-RAY SCATTERING FROM SYNTHETIC POLYMERS, Elsevier: Amsterdam, (1989), and Alexander , L., X-RAY DIFFRACTION METHODS IN POLYMER SCIENCE, Robert Kreiger Pub. Co., New York, (1979)). Upon melting, the crystals require a fixed amount of heat, at the melting temperature, transforming from crystalline material to molten material. This heat of fusion can be measured through various thermal techniques, of which the most popular is the CED. If the heat of fusion of a 100% crystalline material is known and upon heating to the melting point no significant phenomenon of annealing or melting / recrystallization occurs, then the CED can actually accurately determine the crystallinity of the fraction (see THERMAL CHARACTERIZATION OF POLYMER MATERIALS, E. Turi, Ed., Academic Press, New York, (1980); and underlich, B., MACROMOLECULAR PHYSICS, Academic Press, New York, (1980)). If the densities of pure crystalline and amorphous material are known, then the density measurements of a material can provide the degree of crystallinity. This assumes additive properties for specific volumes, although this requirement is fulfilled by polymers (or copolymers) of homogeneous structure. This method depends on a very careful preparation of the sample, in such a way that there are no bubbles or large holes in it. If the absorption bands of crystalline and amorphous materials can be identified, then the infrared absorption spectrum offers a convenient way of determining crystallinity. (See Tadokoro, H., STRUCTURE OF CRYSTALLINE POLYMERS, John Wiley &Sons, New York, (1979)). It should be noted that different techniques will often provide slightly different values of Fc, because they are based on different physical principles. For example, density measurements often provide higher values than diffraction P1298 x-ray. This is due to the continuous change in the density of the interface between the crystalline and the amorphous polymer (or copolymer). While the x-ray diffraction does not detect this matter as crystalline, the density measurements will be affected by this region of the interface. In general, the PHAs of the present invention preferably have a crystallinity of about 0.1% to about 99%, as measured by X-ray diffraction; more preferably from about 2% to about 80%; even more preferably from about 20% to about 70%. When a PHA of the present invention will be converted into a film, the amount of crystallinity in that PHA is more preferably from about 2% to about 65%, as measured by means of x-ray diffraction; more preferably from about 5% to about 50%; still more preferably from about 20% to about 40%. When a PHA of the present invention will be transformed into a sheet, the amount of crystallinity in that PHA is preferably from about 0.1% to about 50%, as measured by x-ray diffraction; more preferably from about 5% to about 50%; still more preferably from about 20% to about 40%. When a PHA of the present invention will be converted into a normal fiber or a non-woven fabric, the amount of crystallinity in that PHA is preferably from about 60% to about 99%, as measured with x-ray diffraction; more preferably from about 70% to about 99%; still more preferably from about 80% to about 99 ^. When a PHA of the present invention will be converted into a soft elastic fiber, the amount of crystallinity in that PHA is preferably from about 30% to about 80%, as measured via x-ray diffraction; more preferably from about 40% to about 80%; still more preferably from about 50% to about 80%. When a PHA of the present invention will be transformed into a molded article, the amount of crystallinity in that PHA is preferably from about 10% to about 80%, as measured with x-ray diffraction; more preferably from about 20% to about 70%; still more preferably from about 30% to about 60%.

P1298 When a PHA of the present invention will be converted into an elastomer or adhesive, the amount of crystallinity in that PHA is preferably less than about 50%, as measured by means of x-ray diffraction; more preferably less than about 30%; still more preferably less than about 20%.

Fusing Temperature Preferably, the biodegradable PHAs of the present invention have a melting temperature (Tf) of from about 30 ° C to about 160 ° C, more preferably from about 60 ° C to about 140 ° C, even more preferably from about 90 ° C. ° C at approximately 120 ° C.

Plastic articles comprising PHA The PHAs of the present invention can be processed into a wide variety of plastic articles, including, but not limited to, films, sheets, fibers, foams, molded articles, non-woven fabrics, elastomers and adhesives.

A. Films In one embodiment of the present invention, the plastic article is a film. How is it used P1298 here, "film" refers to a continuous and extremely thin piece of a substance that has a high ratio of length to thickness and a high ratio of width to thickness. While there is no requirement for a precise upper limit for thickness, the preferred upper limit will be 0.254 mm, more preferably about 0.01 mm, even more preferably about 0.005 mm. The protection value of any film depends on its continuity, that is, it does not have holes or cracks, since it must be an effective barrier for molecules such as atmospheric water vapor and oxygen. The film of the present invention can be used in a variety of disposable products, including, but not limited to, disposable diapers, shrink wrappers (e.g., food wrappers, consumer product wrappers, pallet and / or crate wrappers, and the like). similar) or bags (Supermarket bags, food storage bags, sandwich bags, resealable Ziploc® bags, trash bags and the like). In a preferred embodiment of the present invention, the film of the present invention is impermeable to liquids and suitable for use in disposable absorbent sanitary garments, such as disposable diapers, feminine hygiene products and the like. More preferably, the P1298 films of the present invention, in addition to high biodegradability and / or susceptibility to be transformed into compost, have the following properties: a) a machine direction tension modulus (MD) of from about 10,000 to about 100,000 pounds / square inches ( from 6.895 x 108 dynes / cm2 to 6.895 x 109 dynes / cm2), b) a tear strength in MD of at least 70 grams per 25.4 μm thickness, c) a resistance to tearing in the cross machine direction (CD) of at least 70 grams per 25.4μ of thickness, d) an impact strength of at least 12 cm measured by the drop of a ball, e) a moisture transport velocity of less than about 0.0012 grams per square centimeter in 16 hours, f) a module at 60 ° C of at least 5.52 x 107 dynes / cm2 (800 pounds / square inches in) and g) a thickness of about 12 μm to about 75 μm. The test methods for these performance criteria are described in more detail below. Prior to the invention of the applicants, the polyhydroxyalkanoates studied for use in the P1298 commercial production of plastics, presented significant impediments to their use in plastics. As previously discussed, polyhydroxyalkanoates such as PHB and PHBV copolymer are difficult to process due to their thermal instability. In addition, said polyhydroxyalkanoates were especially difficult to convert into films due to their low crystallization rate. Applicants have found that the PHA copolymers of the present invention, including a second RRMU, as defined above, with a branched alkyl of three (3) carbons, are surprisingly easier to convert into films, especially when compared with PHB or PHBV. Applicants surprisingly discovered that such linear random copolymers having a limited number of branched alkyl chains of medium size containing three (3) carbons, provide, in addition to biodegradability, the following properties, particularly when compared to PHB or PHBV: a) a lower melting temperature, b) a lower degree of crystallinity, and c) an improved melting rheology. This is especially surprising in light of the fact that the longest straight branch of the medium-sized branched alkyl chain contains only two (2) carbons.

P1298 Without being limited by theory, the applicants believe that "characteristics a) and b) are achieved by excluding the second RRMU from the crystal lattice of the first RRMU, in such a way that it produces a decrease in the temperature of the thermal processing and a improvement in stiffness and elongation properties Again, without being limited by theory, applicants believe that feature c) is achieved by increasing the entanglement between the copolymer chains due to the side chains of the second RRMU. in the entanglement it can occur by an increase in the hydrodynamic volume of the copolymer (for example, the second monomeric unit creates curls in the helical structure), the "hooking" or "trapping" of the side chains in the different main chains of the copolymer while Fusion is carried out, or a decrease in chain cleavage due to a smaller Tm (ie, an increase in the process window thermal). 1. Performance criteria and film test methods For a film to perform satisfactorily as a disposable diaper reinforcement sheet, which can be transformed into compost, it must be made from resins or structures that are P1298 biodegradable and must demonstrate the following properties: high strength, adequate barrier against fluids, appropriate modulus or flexibility and a properly high melting point. The disposable diaper reinforcement webs must have sufficient strength to both be processed at high speed in a disposable diaper converting machine, and to provide a "waterproof" barrier during use in infants. It must be sufficiently impermeable so that the infant's bedding as well as his own clothes or that of the person who takes care of him, does not get wet or dirty. It must have a modulus or flexibility that is, at the same time, low enough to be a soft, pleasant material to be used as the outer covering of a child's diaper, but high enough to be easily handled in the processing machines. High-speed disposable diapers, without wrinkling, bending or folding. It must have sufficient heat resistance, so that it does not permanently deform, melt or lose strength in typical hot storage conditions or lose its integrity in high-speed disposable diaper converters that commonly use hot melt adhesives to bond the components of a disposable diaper.

P1298 Films that are strong enough to be used as biodegradable reinforcing liners and / or susceptible to being composted into disposable diapers, preferably demonstrate two properties: (a) breaking strength as a result of weight loss and (b) ) resistance to tearing both in the manufacturing direction in the machine and in the manufacturing direction transverse to the machine. Preferred reinforcing liners of the present invention can withstand the fall of a spherical steel ball of approximately 19 millimeters in diameter and 27.6 to 28.6 grams of mass from a height of 12 centimeters so that at least 50% of the tests have as a result no breakage of any size occurred (the deformation is acceptable). The preferred materials are those that had 50% or less of faults at a height of more than 20 centimeters. Likewise, the acceptable reinforcement canvases of the present invention show an average tear propagation strength of 70 grams per 25.4 microns thickness of the material in both manufacturing directions, both in the machine direction and in the cross machine direction, when using a Elmendorf standard pendulum test device, such as the Elmendorf Model No. 60-100, against 16 layers of material that have been prepared with P1298 a cut or notch according to Method T 414om-88 of TAPPI. More preferred are reinforcing liners showing a tear propagation strength of 200 or more grams per 25.4 microns thickness in the cross machine direction, because these are particularly good at avoiding the tendency to fail by cracking when in use. . It has also been found that films with sufficient barrier to moisture transport are those that allow the passage to an absorbent paper towel of less than 0.0012 grams of synthetic urine per square centimeter of area per 25.4 microns of thickness per 16 hours when The test film is located between the absorbent paper towel and a typical diaper core that contains absorbent gelling material, subjected to a pressure similar to that exerted by a baby. The specific conditions of the test are that the core area is larger than the test material, the core is loaded with synthetic urine up to its theoretical capacity and it was subjected to a weight of approximately 35 g / cm2 (0.5 psi) . It has also been found that materials with sufficient heat resistance show a Vicat softening point of at least 45 ° C. Vicat softening is tested using a Distortion Apparatus for P1298 Heat Model No. CS-107 or equivalent and a modification of the ASTM D-1525 method. The modification is in the preparation of the sample. A film of 19 square millimeters and 4.5 to 6.5 mm thick is prepared for Vicat needle penetration tests by melting the material to be tested in a mold at a temperature of 120 ° C and at a pressure of 7.031 x 105 g / cm2 (10,000 psi) (using a Carver or similar press) for two minutes after a warm-up period of at least 2 minutes. The Vicat softening point is the temperature at which a flattened end needle of circular cross-section of 1 mm square will penetrate the sample to a depth of 0.1 cm under a load of 1000 g, using a uniform rate of temperature increase of 50 ° C per hour. It has also been found that sufficient module materials in the machine direction show a drying module of 1% above at least about 6.895 x 108 dynes / cm2 (10,000 psi) and below about 6.895 x 109 dynes / cm2 ( 100,000 psi). The test is performed on an electronic tension testing machine, such as the Instron Model 4201. A strip of material 2.54 cm wide, preferably 0.00254 cm thick, cut to a length of approximately 30 cm with the longest dimension of the material parallel to the P1298 machine direction. The test strip is clamped in the clamps of the tension tester, so that the caliber or the actual length of the test material is 25.4 cm. The jaws are separated at a slow speed in the range of 2.54 cm per minute to 25.4 cm per minute and on a graph paper, which is inside a connected recording device, a tension-strain curve is plotted. The 1% of the secant modulus is determined by reading the strain or stress at the deformation point with an elongation of 1% from the diagram. For example, the point with deformation of 1% is obtained when the distance between the jaws has increased 0.254 cm. When the jaws are separated at a rate of 2.54 cm per minute and the recording device operates at a speed of 25.4 cm per minute, the 1% deformed point will be located at a distance of 2.54 cm from the initial point. The response to stress is divided by the thickness of the material sample if it is not 0.00254 cm thick. Particularly mild, and therefore preferred, materials exhibit 1% secant modulus in the range of 6.895 x 108 to 2.068 x 109 dynes / cm2 (10,000 to 30,000 psi). Because absorbent articles can experience temperatures as high as 140 ° F (60 ° C) during storage in warehouses or when transported in P1298 trucks or rail vehicles, it is important that the film of the reinforcement canvas and the other components maintain their integrity at these temperatures. Although it is expected that the film modulus will decrease a little, between 20 ° C and 60 ° C, the module should not decrease too much and should allow the film to deform in the package before it reaches the end user. For example, a polyethylene reinforcement sheet with a module at room temperature of approximately 4 x 109 dynes / cm2 (58,000 psi) can have a module at 60 ° C of 1.2 x 109 dynes / cm2 (18,560 psi), which is acceptable. A softer polyethylene reinforcement sheet with a module at room temperature of approximately 8.0 x 108 dynes / cm2 (11,600 psi) may have a module at 60 ° C of approximately 3.5 x 108 dynes / cm2 (5,076 psi) which is still acceptable . In general, an acceptable reinforcing canvas film of the present invention will have a modulus at 60 ° C of at least 5.52 x 107 dynes / cm2 (800 psi). The dependence of the module on temperature, also called module / temperature spectrum, is best measured on a dynamic mechanical analyzer (AMD) such as the Perkin Elmer 7 Series / Unix TMA 7 thermomechanical analyzer equipped with a software package Temperature / Time 7 Series / Unix DMA 7, which, from now on, we will call P1298 DMA 7, available from Perkin-Elmer Corporation of Norwalk, Connecticut. There are many other types of DMA devices and the use of dynamic mechanical analysis for the study of the modulus / temperature spectrums of polymers in well known by those experienced in the technical field of characterization of polymers (or copolymers). This information is well summarized in two books, the first is DYNAMIC MECHANICAL ANALYSIS OF POLYMERIC MATERIAL, MATERIAL SCIENCE MONOGRAPHS VOLUME 1 by T. Murayama (Elsevier Publishing Co., 1978) and the second is MECHANICAL PROPERTIES OF POLYMERS AND COMPOSITES, VOLUME 1 by YOU Nielsen (Marcel Dekker, 1974). The operating mechanisms and procedures for using the DMA 7 can be found in the User Manuals 0993-8677 and 0993-8679 of Perkin-Elmer, both dated May 1991. For those who dominate the use of the DMA 7, the The following conditions will be sufficient to reproduce the module data at 60 ° C presented hereinafter. To measure the modulus / temperature spectrum of a film specimen, the DMA 7 is programmed to run in a temperature sweep mode and is equipped with an extension measurement system (SME). A specimen of film approximately 3 mm wide, 0.0254 mm thick and of sufficient length is mounted in the SME.

P1298 has 6 to 8 mm length between the jaws for the specimen. The apparatus is then enclosed in an environmental chamber continuously swept with helium gas. The tension is applied to the film in the longitudinal direction to obtain a deformation or elongation of 0.1 percent of the original length. A deformation effort of dynamic sinusoidal type is applied to the specimen at a frequency of 5 cycles per second. In the temperature sweep mode, it is increased at a rate of 3.0 ° C / minute from 25 ° C to the point where the material melts or breaks, while the frequency and voltage remain constant. Temperature-dependent behavior is characterized by monitoring the changes in strain and the phase difference in time between stress and strain. The values of the storage module measured in Pascal are calculated by the computer together with other data and are displayed as temperature functions in a video terminal. Normally, the data is saved on the computer's hard drive and a copy of the storage spectrum of the module / temperature is printed for later review. The module at 60 ° C is determined directly from the spectrum.

P1298 2. Film Manufacturing Method Films of the present invention used as reinforcement fabrics that have increased their biodegradability and / or ability to be composted, can be processed using conventional manufacturing methods to produce single layer or multilayer films in conventional machinery to make films. The granules or pellets of the PHAs of the present invention can first be mixed dry and then mixed in a molten state in a film extruder. Alternatively, if mixing is insufficient in the film extruder, the pellets can be dry mixed first and then mixed in the molten state in a premixing extruder, followed by a repelletization before extrusion of the film. The PHAs of the present invention can be melt processed into films, using any of the film extrusion methods, either by casting or by blowing, which are described in PLASTICS EXTRUSION TECHN0L0GY-2 Ed., By Alian A. Griff (Van Nostrand Reinhold - 1976). The cast film is extruded through a linear slot die. Generally the flat membrane is cooled in a large polished metal roll in motion. This cools quickly and detaches from this first roller, passes over one or more rollers of P1298 auxiliary cooling and then through a set of traction rollers or "pulled" rubber coated, and finally to a winder or reel. A method for making a cast reinforcement canvas film for the absorbent articles of the present invention is described below. In blown film extrusion, the melt is extruded up through a thin opening in the annular die. This process is also known as tubular film extrusion. Air is introduced through the center of the die to inflate the tube and thus make it expand. Then a moving bubble is formed, which is maintained at a constant size by controlling the internal pressure of the air. The film tube is cooled by blowing air through one or more cooling rings surrounding the tube. Then the tube collapses by pulling it into a flattening frame through a pair of traction rolls and then into a furler. For reinforcing canvas applications, the flattened tubular film is subsequently opened by cutting it longitudinally, unfolding and then cutting to the proper widths to be used in the products. Both processes for making films, both by blowing and by casting, can be used to manufacture P1298 film structures, either monolayer or multilayer. For the production of monolayer films from a single thermoplastic material or from mixtures of thermoplastic components, only a single extruder and a single distributor die are required. For the production of multilayer films of the present invention, it is preferred to employ coextrusion processes. These processes require more than one extruder and either a coextrusion feed block or a multistrand die system or a combination of the two for obtaining the multilayer film structure. U.S. Patents 4,152,387 and 4,197,069 show the principle of the coextrusion feed block. Multiple extruders are connected to the feed block, in which movable flow dividers are used to proportionally change the geometry of each individual flow channel in direct relation to the volume of polymer passing through said flow channels. The flow channels are designed in such a way that at their point of confluence, the materials flow together at the same flow velocity and at the same pressure, thus eliminating interfacial tension and flow instability. Once the materials are joined in the feed block, they flow through a single distributor die P1298 as a composite structure. In these processes it is important that the viscosities and temperatures of the molten materials do not differ too much; otherwise, flow instabilities can result in the die having poor control of the layer thickness distribution in the multilayer film. An alternative to the coextrusion with feed block is a multidistribution or vane die as shown in the aforementioned US Patents 4,152,387 and 4,197,069 and in U.S. Patent 4,533,308. Whereas in the feedblock system the streams of molten material meet outside and before entering the body of the die, in a multi-distributor or vane die each stream of molten material has its own distributor in the die, where the polymers are They extend independently in their respective distributors. The currents of the molten material meet, with each of the others, near the exit of the die, in all the width of the same one. The mobile vanes provide adjustment of the output of each flow channel in direct relation to the volume of material flowing through it, allowing all the molten material to flow at the same linear flow rate, pressure and desired width. Because the flow properties and P1298 melt temperatures of the processed materials can vary widely, the use of a die of wind vanes has several advantages. The die lends itself to thermal insulation characteristics, where materials with very different melting temperatures, for example, up to 175 ° F (80 ° C), can be processed together. Each distributor on a vane die can be designed and adapted to a specific polymer (or copolymer). Thus, the flow of each polymer is only influenced by the design of its distributor, and not by forces imposed by other polymers. This allows melted materials with very different viscosities to be coextruded into multilayer films. Additionally, the vane die also provides the ability to adjust the width of the individual distributors to the desired size, such that an inner layer of, for example, a biodegradable water-soluble polymer, such as Vinex 2034, can be completely surrounded by insoluble materials in water, without leaving exposed any edge susceptible to water. The aforementioned patents also show the combined use of power block systems and vane dies to achieve more complex multilayer structures. The multilayer films of the present invention can include two or more layers. In general, they are preferred P1298 balanced or symmetrical three-layer or five-layer films. The three layer multilayer balanced films include a core core layer and two identical outer layers, wherein the core core layer is placed between the outer layers. The five layer multilayer balanced films include a core core layer, two identical tie layers and two identical outer layers, wherein said core core layer is placed between the two aforementioned fastener layers and one of the grip layers is placed between the two core layers. mentioned central core layer and each of the outer layers. Balanced films, while not essential for the films of the present invention, are less prone to curl or twist than unbalanced multilayer films. In the three-layer films, the core core layer may comprise 30 to 80 percent of the total thickness of the film and each outer layer comprises 10 to 35 percent of the total thickness of the film. The fastener films, when used, each comprise from about 5 percent to about 10 percent of the total thickness of the film.

P1298 B. Plates In one embodiment of the present invention, the plastic article is a sheet. Where, "sheet" refers to a very thin continuous piece of a substance, which has a high ratio of length to thickness and a high ratio of width to thickness, where the material is thicker than 0.254 mm. The laminate shares many of the same characteristics of the film in terms of properties and manufacturing, with the exception that the laminate is more rigid, and has a self-supporting nature. These differences in rigidity and support result in some modification in the manufacturing methods. 1. Manufacturing methods The sheets, due to the thickness and consequent stiffness, can not be blown like a film. However, to make sheets, many other of the same film manufacturing processes can be modified. An example is the cast extrusion described above. In addition to extrusion, rolling is also done by rolling and calendering. to. Rolling Rolling produces a film with a P1298 predominant orientation in machine direction accelerating the film from a point of grip where the thickness is reduced (ENCICLOPEDIA OF POLYMER SCIENCE AND ENGINEERING, Vol. 8, pp. 88-106, John Wiley and Sons, New York, (1986) , hereinafter referred to as "EPSE-1"). At the point of grip there are large forces, although the full orientation can be increased above other forms of orientation in the machine direction. b. Calendering To produce a non-oriented cast film or film with high performance, calendering is used (G. W. Eghmy, Jr. In MODERN PLASTICS, J. Agrandoff, ed. ? ncyclopedia, Vol 59 (10A), pp. 220-222 (1982) and R. A. Elden and A. D. Swan, CALENDERING OF PLASTICS, American Elsevier Co., Inc., New York, (1971)). The calendering process uses stacks of rollers transmitted with special hardening and supported in such a way that they can bend or deviate from their position, with respect to the other, during operation. This is for the purpose of controlling the thickness in the calendered material. Calenders are usually composed of four rollers that form three grip points. These grip points are the loading or feeding, the calibration or measurement and the finishing. The feeding grip point is where the polymer is P1298 supplies, mixes and heats. The measurement grip reduces the thickness of the sheet to the approximate final thickness. The finishing grip adjusts the gauge of the blade by varying the position of the third roller or the middle roller. (See EPSE - 2).

C. Fibers In one embodiment of the present invention, the plastic article is a fiber. Where, "fiber" refers to a flexible body, microscopically homogeneous, having a high proportion of length to width and a small cross section. A general description of the fibers can be found in ENCYCLOPEDIA OF POLYMER SCIENCE AND ENGINEERING, Vol. 6, p. 647-755 and pp. 802-839, John Wiley and Sons, New York, (1986) (hereinafter referred to as "EPSE-2"). The fibers of the present invention are useful as textiles in garment yarns. The fibers of the present invention are also useful for making fibrous and lightweight materials useful in agricultural applications to protect, promote or control the growth of plants. They are also used in greenhouse thermal screens, crop line covers, turf decks, weed barriers and in hydroponics. The important properties are permeability to light, air and moisture. A P1298 important aspect is the good cost-benefit ratio when considered in terms of weight, strength and dimensional stability. An elastomeric fiber is a fiber that consists of polymers (or copolymers) with a main glass transition temperature much lower than the ambient temperature (see EPSE-2). This criterion excludes some fibers with elastic properties, such as curled hard fibers, but allows the inclusion of multifunctional fibers, wherein one of the constituents is an elastomer. All the elastomeric fibers are characterized by a greater elongation in the rupture, a lower modulus and an upper recovery starting from a great deformation, than the normal fibers. 1. MANUFACTURING METHODS The fibers of the present invention can be manufactured using a variety of conventional techniques well known in the technical field including, but not limited to, melt spinning, dry spinning and wet spinning. Often combinations of these three basic processes are used. In melt spinning, a PHA of the present invention is heated above its melting point and the molten PHA is passed through a spinning nozzle.

P1298 A spinning nozzle is a die with many small holes that vary in number, shape and diameter (see EPSE-2). The molten PHA jet is passed through a cooling zone, where the PHA solidifies and then transferred to the post-stretched and rolled equipment. In dry spinning, a PHA of the present invention is dissolved and the PHA solution is extruded under pressure through a spinning nozzle (see EPSE-2). The PHA solution jet is passed through a heating zone where the solvent evaporates and the filament solidifies. In wet spinning, a PHA of the present invention also dissolves and the solution is passed through a spinning nozzle which is immersed in a coagulation bath (see ESPE-2). As the PHA solution emerges from the orifices of the spinning nozzle within the coagulation bath, the PHA is precipitated or chemically regenerated. Normally, all these processes need further stretching to obtain useful properties, for example, to serve as textile fibers. "Stretching" refers to a stretching and attenuation of the fibers to achieve an irreversible extension, induce molecular orientation and develop a fine structure of the fiber (see ESPE-2). This fine structure is characterized by a high degree of crystallinity and by the P1298 orientation of both amorphous and crystalline PHA chain segments.

D. Foams In one embodiment of the present invention, the plastic article is a flexible foam. As used herein, "foam" refers to the PHA of the present invention whose bulk density has been substantially decreased by the presence of numerous cells distributed throughout its mass (see ASTM D 883-62T, America Society for Testing Materials, Philadelphia, Pa., (1962)). These two-phase gas / solid systems in which the solid is continuous and composed of a synthetic or polymeric rubber, include cellular polymers (or copolymers), expanded plastics and foamed plastics. (ENCICLOPEDIA OF CHEMICAL TECHNOLOGY, Vol.11, John, Wiley &Sons, New York (1980), hereinafter referred to as the "ECT"). The gaseous phase is distributed in pockets or holes called cells, which are classified into two types, open and closed. The open cell materials are foams whose cells are interconnected in such a way that the gases can traverse the cells freely. Closed cell materials have cells that are discrete and that are isolated from each other.

P1298 The foams are further classified into flexible and rigid foams. This classification is based on a particular ASTM test procedure (see ASTM D, Vol. 37, pp. 1566-1578, American Society for Testing the Materials, Philadelphia, Pa., (1978)). A flexible foam is a foam that does not break when a piece of 20 x 2.5 x 2.5 cm is wrapped around a 2.5 cm mandrel at a uniform speed of 1 turn / 5sec at a temperature of 15-25 ° C. that break when subjected to this test are called rigid foams. Foams have many applications such as in packaging, in comfortable cushioning, in insulation, and in structural components. In some packaging areas a foamed material, such as polystyrene, paper and starch foams, which has increased its biodegradability and / or capacity to be transformed into compost, would offer superior benefits to the packaging currently used. In hot food containers, polystyrene offers significantly higher thermal insulation than the only currently degradable alternative, paper wrappers. The foamed articles comprising a PHA of the present invention have the thermal insulation properties of the polystyrene and are also biodegradable and / or susceptible to being transformed into compost. These materials are ideal for hot food to be packed and packed P1298 of cold food. Splinters or foamed polystyrene pieces are used as cushioning materials in the packing of consumer and industrial articles. Many of these splinters end up in landfills. The foamed chips comprising a PHA of the present invention perform as well as polystyrene and have a higher biodegradability and / or ability to be transformed into compost. Unlike other packaging materials that can be composted, such as starch, these PHA chips are resistant to many common solvents and liquids, including water. 1. Foam Manufacturing Methods The foams of the present invention can be made using conventional methods well known to those who dominate the technical field in this area. A predominant method of foam production involves the expansion of a fluid polymer (or copolymer) phase to a low density cellular phase and subsequently retaining this state (see ECT). Other processes include the leaching of materials that have previously been dispersed in the polymer (or copolymer), the sintering of small particles and the dispersion of P1298 the cellular particles in a polymer (or copolymer). The expansion process consists of three steps. These are: initiation of the cell or cell, growth or development of the cell and stabilization of the cell. There are many methods to create, develop and stabilize cells. Expandable formulations are based on increasing the pressure within the initiation cells relative to those in the surroundings. The cells are stabilized by any means, be it chemical (for example crosslinking, polymerization) or physical (crystallization, fusion-glass transition). Polystyrene is an example of a polymer that is foamed by this type of process. A foaming agent such as the isomers of pentanes, hexanes or halocarbons, (HR Lasman, MODERN PLASTICS, Vol. 42 (IA), page 314 (1964)) is mixed with the polymer (or copolymer) either by heating and allowing that the foaming agent penetrates the polymer (U.S. Patent 2,681,321, issued June 15, 1954, F. Stastny and R. Gaeth, assigned to BASF), or by polymerizing the polystyrene in the presence of the foaming agent ( U.S. Patent 2,983,692, issued May 9, 1961, GF D'Alelio, assigned to Koppers Co.). The manufacture of articles is normally carried out in multiple steps, P1298 the first of these uses water vapor, hot water or hot air to expand the polymer into preformed low density pellets. These preformed globules are allowed to stand, sometimes in multiple steps to correct cell size, and then packaged in molds and joined by heat fusion and then expanded (SJ Skinner, S. Baxter, and PJ Gray, Trans. J. PLAST, INST.Vol, 32, p.180 (1964)). The stabilization is carried out by cooling the polymer to temperatures below its glass transition temperature. Decompression expansion processes create and develop cells by decreasing external pressure during the process. Cellular polyethylene and polypropylene are generally made in this way. A defoaming foaming agent is premixed with the polymer (or copolymer) and fed to an extruder at elevated temperature and pressure, such that the foaming agent is partially decomposed. When the material leaves the extruder, it enters an area of lower pressure. Subsequently, a simultaneous expansion and cooling occurs, resulting in a stable cellular structure that is due to the rapid crystallization of the polymer (R. H. Hansen, SPE J., Vol. 18, p.77 (1962), W. T.

Higgins, MOD. PLAST., Vol. 31 (7), p. 99, (1954)). Dispersion processes produce foam P1298 directing the phase of the solid or dispersed gas to the polymer (or copolymer) and subsequently, when necessary, stabilizing the mixture (ECT). In this foaming process, a gas is mechanically dispersed in the polymer or monomer phase and produces a foam of temporary stability. This foam is then chemically stabilized by crosslinking or polymerization. Latex foam rubber is manufactured in this way (see ECT).

E. Molded articles In one embodiment of the present invention, the plastic article is a molded article. As used herein, "molded article" refers to objects that are formed from polymer or copolymer materials (e.g., PHA), which are injected, compressed, or blow by means of a gas, in a manner defined by a female mold. These objects can be solid objects like toys, or holes like bottles and containers. The injection molding of thermoplastics is a multi-step process in which a PHA of the present invention is heated to melt, then passed to a closed mold where it is shaped and finally solidified by cooling. There are a variety of machines that are used in injection molding. Three types P1298 common are hydraulic ram, screw plasticizer, hereinafter referred to as spindle, with injection, and reciprocating spindle devices (see ENYCLOPEDIA OF POLYMER SCIENCE AND ENGINEERING, Vol. 8, pp. 102-138, John Wiley and Sons, New York, (1986), hereinafter called "EPSE-3"). A hydraulic ram injection machine is composed of a cylinder, an extender, and a plunger. The plunger passes the melt to the mold. A plasticizing spindle with a second injection phase, consists of a plasticizer, a directional valve, a cylinder without an extender and a hydraulic ram. After the plasticization by the spindle, the hydraulic ram passes the melt to the mold. A reciprocating spindle injection machine consists of a barrel and a spindle. The spindle rotates to melt and mix the material and then advances to pass the melt to the mold. Compression molding in thermoplastics involves loading an amount of PHA of the present invention into the lower half of an open die. The upper and lower halves or base of the die are joined under pressure and then the molten PHA is adapted to the shape of the die. Then the mold cools to solidify the plastic (see EPSE-3). Blow molding is used to make bottles P1298 and other hollow objects * (see EPSE-3). In this process, a cast PHA tube called candle or parison is extruded into a hollow, closed mold. Then, the parison is expanded by a gas and pushes the PHA against the walls of the mold. Subsequently the cooling solidifies the plastic. The mold is then opened and the article is removed. Blow molding has several advantages over the injection molding method. The pressures used are much lower than in injection molding. Blow molding can typically be achieved at pressures of 25-100 psi between the plastic and the mold surface. In comparison, in injection molding pressures can reach 10,000 to 20,000 psi (see EPSE-3). In cases where the PHA has very high molecular weights to allow easy flow through the molds, blow molding is the technique of choice. Polymers (or copolymers) of high molecular weight often have better properties than their low molecular weight analogues, for example, high molecular weight materials have higher resistance to stress cracking (see EPSE-3). With blow molding it is possible to produce products with very thin walls. This means a lower amount of PHA used and shorter solidification times, resulting in lower costs through material preservation and higher savings. Other P1298 important aspect of the blow molding is that because it only uses a female mold, small changes in the extrusion conditions in the nozzle of the parison can vary the thickness of the wall (see EPSE-3). This is an advantage with structures whose wall thicknesses can not be predicted in advance. The evaluation of articles of various thicknesses can be undertaken and the thinnest item used, and therefore, the lightest and most economical one that complies with the specifications.

F. Nonwoven In one embodiment of the present invention, the plastic article is a nonwoven. Where "nonwoven" refers to a porous textile type material, generally, in the form of a flat sheet, composed principally or completely of fibers assembled into wefts that are manufactured by processes other than spinning, weaving or sewing. A general description of non-woven fabrics can be found in the ENCYCLOPEDIA OF POLYMER SCIENCE AND ENGINEERING, Second Edition, Vol. 10, p. 204-226 (hereinafter referred to as "EPSE-4"). Other names for these materials are attached fabrics, formed fabrics or designed fabrics. The thickness of the fabric sheets can vary from 25 mm to several centimeters and the weight from 10 g / m2 to 1 kg / m2. Non-woven fabrics have a P1298 wide range of physical properties that depend on the material and process used for the formation of the frame. A fabric can have its own support and be rigid like paper or with a fall like that of a conventional cloth for clothes. In contrast to conventional textiles, the fundamental structure of all nonwovens is a web of fibers placed more or less randomly (NONWOVENS IND., Vol. 17, page 36 (Mar. 1986), NONWOVWNS WORLD, Vol. 1 , page 36 (1986 May-June) Thus, the key element is the single fiber.The tensile, tear and tactile properties in nonwovens arise from the adhesive bond or from other physical and chemical bonds, fiber friction against fiber created by entangling and reinforcement by other materials such as foams and films (see EPSE-4). 1. Method of manufacturing non-woven fabrics The non-woven fabrics of the present invention can be made by conventional techniques known in the technical field. The production of non-woven fabrics involves: 1) making fibers of various lengths and diameters; 2) create a web of these fibers; and 3) joining the fibers in the weft by means of adhesives or by mechanical friction forces created by the entanglement or contact P1298 fiber In addition to these steps, it is sometimes preferred to reinforce the network by forming a composite with other materials (eg, yarns, gauze, films, networks, and unattached wefts). The variations of one or several of these steps allow a huge range of types of non-woven fibers. The term "cut fibers" was originally applied to fibers of natural origin of sufficient length to be processed in the textile machinery, but excluding endless or endless filaments, such as silk. In the present context, as applied to the PHA of the present invention, the "staple fibers" are of relatively uniform length, from about 1.3 to 10.2 cm, with a regular ripple, that is, a three-dimensional shape similar to a wave. Regenerated fibers and other extruded fibers are endless when they are formed. During the manufacturing process they are cut to specific lengths to satisfy the needs of the process or the market. Extruded fibers are also produced as a continuous filament without ripple. The processes by forming wefts from staple fibers are different from those that are used for continuous filaments. Products obtained from main fiber webs and filament fiber webs may differ substantially in properties (see EPSE-4).

P1298 The mechanical properties of the fibers as defined by their chemical composition finally determine the properties of the fabric. The structure of the weft and its union increase to the maximum the inherent characteristics of the fiber (see EPSE-4). Other materials that can be used in the non-wovens of the present invention in combination with the PHA are wood pulp; regenerated fibers including viscose, rayon and cellulose acetate; and synthetic fibers such as poly (ethylene terephthalate) (PET), nylon-6, nylon 6,6, polypropylene (PP) and polyvinyl alcohol. Faces or fronts of disposable diapers or sanitary napkins made from non-woven fabrics of the PHA of the present invention, they feel preferably dry, even when the absorbent, the inner layer of absorbent is saturated. The important characteristics of the fiber that affect the behavior include length, diameter, density, curl, the shape of the cross section, the spin finish (lubricant is added to the surface of extruded fibers to improve ease of processing), tarnishing ( small amounts of Ti02 pigment are added, before extrusion, to increase whiteness or reduce luster) and the stretch ratio.

P1298 a. Methods of framing The characteristics of the fiber plot determine the physical properties of the final product. These characteristics depend, to a great extent, on the architecture of the fiber, which is determined by the mode of formation of the frame. The fiber architecture includes the predominant direction of the fiber, whether it is oriented or random, the shape of the fiber (straight, curved or curled), the extension of the interfiber webbing or interlock, the curling and compaction (control of the fiber). plot density). The characteristics of the weft are also influenced by the diameter of the fiber, its length, the weight of the weft, and the chemical and mechanical properties of the polymer (see EPSE-4). The selection of the method to form the weft is determined through the length of the fiber. Initially, the methods for forming wefts from staple fibers (fibers of sufficient length to be handled by the conventional spinning equipment, usually from about 1.2 to about 20 cm, but not endless) were based on the textile carding process, while the formation of the weft from short fibers is based on papermaking technologies. Although these technologies are still in use, subsequent methods have been developed. By P1298 example, plots that are formed of long filaments, virtually endless, directly from the polymer mass; both the fibers and the wefts are produced simultaneously (see EPSE-4). A variety of methods are known for making wefts, including carding, air laying, wet forming, bonding spinning and blow melting. The carding process is derived from the old manual methods of fiber carding, where the natural cut fibers were manipulated by needle beds. In carding, the groups of staple fibers are mechanically separated into individual fibers and form a coherent pattern by the mechanical action of the movement of needle beds with very little separation. In the air laying process, the orientation created by the carding is effectively improved by capturing on a screen or sieve the fibers that go in a stream of air (see U.S. Patent No. 3,338,992, GA Kinney, assigned to The du Pont de Nemours &Co., Inc., issued on August 29, 1967). The fibers are separated by teeth or needles and introduced into a stream of air. The total randomization would exclude any preferential orientation When the fibers are collected in the sieve. Wet forming processes employ P1298 very short fibers. Initially, the wefts are formed from short fibers by modifications to the techniques of papermaking. The fibers are continuously dispersed in a large volume of water and collected in an endless mesh of moving wire. Once the fabric is placed over the mesh, it is transferred to strips or felts and dried in hot drums (see EPSE-4). The spunbond process involves the simultaneous manufacture of fibers and wefts, directly from the mass of the polymer. The polymer mass is melted, extruded, and stretched (often by means of triboelectric forces) into filaments that are randomly deposited on webs as a continuous web. The filaments are virtually endless. The bond spinning process produces low curly filament webs in the range of normal diameters of approximately 1.7 dtex (1.5 den) or slightly higher. The birefringence and uniformity of diameters of these filaments are similar to those of standard textile fibers and filaments (see EPSE-4). Each production line is suitable for a specific polymer and a single-bond system (see U.S. Patent 4,163,305 (Aug. 7, 1979), V. Semjonow and J. Foedrowitz (from Hoechst AG)).

P1298 Plots are also made directly from the polymer mass by means of the melt-blow process (see U.S. Patent No. 3,322,607, S.L. Jung, assigned to E.I. Du pont de Nemours &; Co., Inc., May 30, 1967). The molten PHA is passed through very thin holes in a special die in a high velocity air stream where the PHA is transformed into very fine, albeit irregular filaments of indeterminate length. The filaments simultaneously become a network where fusion and resolidification and, possibly static forces, hold them together (see EPSE-4). The plot consists mainly of filaments with very fine diameters. b. Union of the plot The union of the fibers gives resistance to the plot and has influence on other properties. Both adhesive and mechanical means are used. The mechanical union consists of locking the fibers by means of friction forces. Bonding can also be achieved by chemical reactions, that is, the formation of covalent bonds between the binder and the fibers (see EPSE-4).

G. Elastomers In one embodiment of the present invention, the P1298 plastic article is an elastomer. As used herein, "elastomer" refers to materials that have high deformation capacity with the application of stresses and essentially recover fully when these efforts are removed. A general description of elastomers can be found in the ENCYCLOPEDIA OF POLYMER SCIENCE AND ENGINEERING, Second Edition, Vol. 5, pp. 106-127 (hereinafter referred to as "EPSE-5"). Preferably, an elastomer of the present invention, at room temperature, can be repeatedly stretched to at least twice its original length and, after the removal of the stress load, immediately and obligatorily returns to approximately its original length. The elastomers of the present invention are above the glass transition temperature Tg and are amorphous in the unstressed state to show the high local segmental mobility necessary for deformation. The chains are flexible and the intermolecular forces (between chains) are weak. The elastomers of the present invention possess a sufficient number of chemical or physical crosslinks to form a continuous network in such a way that the sliding of the chains is restricted. The thermoplastic elastomers of the present invention have many of the properties of conventional elastomers, such as vulcanized rubbers, P1298 but are processed as thermoplastics instead of as thermosets. The transition from a molten molten material to a solid is reversible. The thermoplastic elastomers of the present invention are multiphase systems, wherein at least one phase is soft and elastic and the other hard. In thermoplastic elastomers, the transition from a processable melt to a solid, of an elastic type object, is rapid and reversible and takes place with cooling. Preferably, the PHAs of the present invention which are transformed into an elastomer, have a sufficiently high content of branches to allow them to act as thermoplastic elastomers, wherein the crystalline areas act as the hard segment and the amorphous segments act as the soft segment. The thermoplastic elastomers of the present invention can be processed in conventional equipment for plastics, such as injection molding. The important structural parameters of the thermoplastic elastomers are the molecular weight, the nature of the soft and hard segments and the ratio of soft segments to hard segments. The ratio of soft to hard segments affects the total modulus of the elastomer, which increases with the proportion of hard segments. The elastomers of the present invention, which P1298 includes a PHA of the present invention, may also be used in formulations in which they are mixed with other polymers (or copolymers), even with non-elastomeric PHA, to increase impact strength and toughness in more rigid materials.

H. Adhesive In another embodiment of the present invention, the plastic article is an adhesive. As used herein, "adhesive" refers to a material that joins two other materials, called adherends. A general description of adhesives can be found in Encyclopedia of Polymer Science and Engineering, Vol. 1, p. 547-577, (hereinafter referred to as "EPSE-6"). In one embodiment of the present invention, the adhesive is applied as a liquid, preferably of low viscosity. In the liquid form, the adhesive wets the surface of the adherend and flows into the surface fissures. The liquid form of the adhesive is obtained by heating it to the point where the fluidity or runoff occurs, by dissolving or dispersing the material in a solvent or, starting with liquid monomers or oligomers that polymerize or react after its application. The adhesive then undergoes a change from phase to solid, either by cooling, by evaporation of the solvent, or by reaction, P1298 so that the board acquires the necessary resistance against the shearing force. However, pressure sensitive adhesives are an exception, since no phase change occurs. The PHAs of the present invention can be converted into a variety of adhesives, including, but not limited to, hot melt, solution, dispersion and pressure sensitive adhesives. 1. Hot Melt Adhesives As used herein, "hot melt adhesive" refers to thermoplastic polymers or copolymers, (e.g., a PHA of the present invention) which upon being heated produce a liquid of such viscosity that it can flow and, after its application, a solid is obtained upon cooling. Generally, the molecular weight of the adhesive is adjusted to provide fluidity in the molten state, but which remains strong enough in solid form to withstand the shearing force experienced during the application. Due to their thermoplastic properties, the PHAs of the present invention are particularly useful as hot melt adhesives. The primary feature of hot melt adhesives is the ability of the thermoplastic material to flow above a certain P1298 temperature sufficiently above the normal temperature of use of the joint. When applying cooling, the material hardens, either by passing through the vitreous transition temperature of one of the components, or by the crystallization temperature. This hardening gives physical integrity to the union. In PELA, the solidification mode is crystallization. 2 - . 2 - Solutions and dispersions The adhesives of the present invention can be applied either as solutions, in water or in an organic solvent, or in the form of aqueous dispersions. In either form, the solvent must be removed after the application of the adhesive to achieve the required solid form. The solution or dispersion is generally applied to one of the surfaces to be joined, and the solvent is removed before the second surface is joined; frequently, heating is required to accelerate the drying step. With porous substrates, such as paper or wood, a final drying can be carried out after the formation of the joint. The solids content in the solutions varies from 5 to 95%, although values between 20 and 50% are the most common. As used herein, "dispersion" refers to when the adhesives are prepared by means of the true P1298 polymerization by emulsion or by the dispersion of large particles in some transport fluid. In addition to its economic advantage, dispersions containing 40-50% solids have a lower viscosity than solutions, even when the solids are high molecular weight polymers (EPSE-6). The dispersions of adhesives of the present invention can be prepared by high shear or shear, in the presence of surfactants to obtain aqueous formulations, processes which are well known to those skilled in the art. 3. Pressure Sensitive Adhesives Another type of adhesive of the present invention is a pressure sensitive adhesive. Unlike other adhesives, pressure sensitive adhesives do not change their physical condition from the initial application until the final break of the union. These adhesives are permanently deformable and can be altered even with the application of light pressure. They are adhesives that in dry form are permanently sticky at room temperature and that stick firmly to surfaces with simple contact. The most common form of a pressure sensitive adhesive is that found on a back or back, usually in the form of adhesive tape. For example, the tape to cover common, applies P1298 manually after the user cuts the desired length from a roll. Many bandages are held on the skin by means of pressure sensitive adhesives.

Disposable Personal Care Products The present invention relates to disposable personal care products containing a PHA of the present invention. For example, absorbent articles capable of being composted comprise a liquid permeable top sheet, a liquid impervious backing sheet, which includes a film of the present invention (ie, a film comprising a PHA of the present invention) , and an absorbent core located between the upper canvas and the reinforcing canvas. These absorbent items include infant diapers, incontinent adult pads and pads, and feminine hygiene pads and protectors. Additional personal care products comprising a PHA of the present invention include wet towels for personal cleansing; disposable health care products, such as bandages, wound dressings, wound cleaning pads, surgical gowns, surgical covers, surgical pads; other disposable products P1298 institutional and health care, such as, gowns, wet wipes, pads, bedding items, such as sheets and pillowcases and foam mattresses.

A. Absorbent Articles The films of the present invention used as liquid impervious reinforcing canvases in the absorbent articles of the present invention, such as disposable diapers, typically have a thickness of 0.01 mm to about 0.2 mm, preferably 0.012 mm to about 0.051 mm. In general, the liquid-impermeable reinforcement canvas is combined with a liquid-permeable upper canvas and an absorbent core placed between the upper canvas and the reinforcing canvas. Optionally, elastic members and fastening clips can be included. While the upper canvas, the reinforcing canvas, the absorbent core and the elastic members can be assembled in a variety of well-known configurations, a preferred diaper configuration is generally described in United States Patent 3,860,003, entitled "Contractible Side Portion for disposable Diapers ", awarded to Kenneth B. Buell on January 14, 1975. The upper canvas is preferably soft to the P1298 touch and not irritating the skin of users. In addition, the upper canvas is permeable to liquids and allows liquids to penetrate through its thickness. A satisfactory topcoat can be manufactured with a wide range of materials, such as porous foams, cross-linked foams, plastic films with openings, natural fibers (e.g., wood or cotton fibers), synthetic fibers (e.g., polyester fibers) or polypropylene) or from a combination of natural and synthetic fibers. Preferably, the upper canvas is made of a hydrophobic material to isolate bare skin from the liquids of the absorbent core. A preferred feature of the upper canvas comprises fibers cut to a length of approximately 1.5 deniers. As used herein, the term "fibers cut to a length" refers to fibers having a length of at least 16 mm. There are several industrial techniques that can be used to make the upper canvas. For example, the upper canvas can be woven, non-woven, spun, carded or the like. The preferred top canvas is carding, and thermally bonded by well-known processes for those who dominate the technical field. Preferably, the top canvas has a weight of about 18 to about 25 g / m2, a P1298 minimum dry tensile strength of at least about 400 g / cm in the machine direction and a wet tensile strength of at least about 55 g / cm in the transverse direction of the machine. In a preferred embodiment part of the present invention, the top canvas includes a PHA of the present invention. The upper canvas and the reinforcing canvas are joined by any convenient manner. As used here, the term "attached" refers to configurations in w the upper canvas is directly attached to the reinforcing canvas by directly fixing the upper canvas to the reinforcing canvas, or the configurations in w the upper canvas indirectly attaches to the reinforcing canvas fixing the canvas superior to intermediate members, w in turn are fixed to the reinforcement canvas. In a preferred embodiment, the upper canvas and the reinforcing fabric are fixed directly to each other at the periphery of the diaper, by some means of attachment, such as an adhesive or any other means of attachment known in the technical field. To fix the upper canvas to the reinforcing canvas, for example, a continuous and uniform layer of adhesive, a layer of adhesive following a pattern or an array of lines can be used.

P1298 separated or areas of adhesive. In a preferred embodiment of the present invention, the adhesive comprises a PHA of the present invention. The tape fastening clips are typically applied to the region of the back of the diaper waist to provide a fastening means for holding the diaper on the wearer. The tape fastening clips may be any of those well known in the art of the art, such as the tape fastening fastener described in United States Patent 3,848,594, issued to Kenneth S. Buell on November 19. of 1974. These tape fastening clips or other diaper fastener means are typically applied near the corners of the diaper. Preferred diapers have elastic members disposed at the periphery of the diaper, preferably along each longitudinal edge so that the elastic members tend to stretch and hold the diaper against the legs of the wearer. The elastic members are secured to the diaper in a contractile condition, so that in a normally free or unrestricted configuration, the elastic members effectively contract or pick up the diaper. The elastic members can be secured in the contractile condition in at least two ways. For example, P1298 elastic members can stretch and secure while the diaper is in a relaxed condition, ie, not contracted. Alternatively, the diaper can be contracted, for example, by folding an elastic member secured and attached to the diaper while the elastic members are in their relaxed or non-contracted condition. The elastic members can adopt a multitude of configurations. For example, the width of the elastic members may vary from about 0.25 mm to about 25 mm or more; the elastic members may contain a single cord of elastic material or the elastic members may be rectangular or curvilinear in shape. Still further, the elastic members can be fixed to the diaper in any of the various manners known in the technical field. For example, the elastic members can be attached to the diaper by ultrasound, heat and pressure sealing, using a variety of bonding patterns, or the elastic members can simply stick to the diaper. In a preferred embodiment of the present invention, the elastic members comprise a PHA of the present invention. The absorbent core of the diaper is placed between the upper canvas and reinforcement canvas. The absorbent core can be manufactured in a wide variety of sizes and P1298 shapes (for example, rectangular, hourglass-shaped, asymmetrical, etc.) and a wide variety of materials. However, the total absorbent capacity of the absorbent core must be compatible with the liquid loading designed for the intended use of the absorbent article or diaper. Moreover, the size and absorbent capacity of the absorbent core can be varied such that they can accommodate users ranging from infants to adults. A preferred diaper embodiment has an absorbent core in the shape of an hourglass. The absorbent core is preferably an absorbent member comprising a weft of synthetic fiber to the air, fibers of wood pulp and / or an absorbent particulate polymer composition placed therein. In a preferred embodiment of the present invention, the polymeric absorbent of the absorbent core includes a PHA of the present invention. Other examples of absorbent articles, according to the present invention, are sanitary napkins designed to receive and contain vaginal discharges, such as, for example, menstrual flows. Disposable sanitary napkins are designed to be held adjacent to the human body by means of a garment, P1298 such as an undergarment or panties or a specially designed belt. In the United States Patent 4,687,478, entitled "Shaped Sanitary Napkin with Flaps", awarded to Kees J. Van Tilburg on August 18, 1987, and in U.S. Patent 4,589,876, entitled "Sanitary Napkin," issued to Kees J. Van Tilburg on June 20, 1987. May 1986, examples of the types of sanitary napkins to which the present invention readily adapts are shown. It is evident that the films of the present invention, including a PHA of the present invention, described herein, can be used as liquid impervious reinforcing canvases in said sanitary napkins. On the other hand, it is understood that the present invention is not limited to any specific sanitary towel configuration or structure. In general, sanitary napkins include a liquid-impermeable backing sheet, a liquid permeable top sheet, and an absorbent core placed between the backing canvas and the top canvas. The reinforcement web includes a PHA of the present invention. The top canvas may include any of the aforementioned upper canvas materials with respect to the diapers. The adhesives employed may also include a PHA of the present invention. The absorbent core can include any of the materials of the P1298 absorbent core mentioned with respect to diapers, including a PHA of the present invention. Importantly, the absorbent articles according to the present invention are biodegradable and / or susceptible to being transformed into compost to a greater degree than conventional absorbent articles employing materials such as a polyolefin reinforcing canvas. (for example, polyethylene).

EXAMPLE 1 Poly (3-hydroxybutyrate-co-3-hydroxy-4-methylvaleriato) Poly (3-hydroxybutyrate-co-3-hydroxy-4-methylvaleriato) is prepared according to the general methods described above and based on the procedure published by Hori et al. (Hori, Y., M. Suzuki, Y. Takahashi, A. Yomaguchi, and T. Nishishita, MACROMOLECULES, Vol. 26, pp. 5533-5534 (1993)) for the polymerization of β-butyrolactone. Specifically, in a dry glass tube, purged with argon and sealed with membrane are loaded by means of a syringe ([S] -3-methylpropiolactone ([S] - ß-butyrolactone) (9.50 g, 110 mmol) and [S] - Purified 3-isopropylpropiolactone (0.83 g, 5.8 mmol) The initiator, 1,3-dichloro-1,3,3-tetrabutyldistannoxane prepared according to R. Okawara and M. Wada, (J. ORGANOMET. CHEM. (1963) , vol.1, pp. 81-88) and P1298 dried overnight under vacuum at a temperature of 80 ° C, dissolved in dry toluene to make a 0.18 M solution. 0.65 ml of the starter solution (0.12 mmol of diestanoxane) is added to the tube by means of a syringe. . The tube is gently shaken to mix the contents and then heated at 100 ° C for 4h, submerging its lower half part in an oil bath. As the reaction proceeds, the contents of the tube become viscous. After the required time, the tube is removed from the oil bath and cooled to room temperature. The solid dissolves in chloroform. It is recovered by precipitation in a mixture of hexane and ether, collected by filtration and dried under vacuum. The composition of the copolymer comonomer is determined through 1 H-NMR spectroscopy and, within the limits of experimental error, it is found to correspond to the charge ratio (95: 5). The molecular weight is determined by size exclusion chromatography with chloroform as the mobile phase and very closed polystyrene standards are used for the calibration.

EXAMPLE 2 Poly (3-hydroxyvaleriato-co-3-hydroxy-4-methylvaleriato) Poly (3-hydroxyvaleriato-co-3-hydroxy-4-methylvaleriato) is prepared following the same procedure as in Example 1, with the exception of that what is used P1298 as charge monomers is [S] -3-ethylpropiolactone (9.50 g, 94.9 mmol) and [S] -3-isopropylpropiolactone (0.71 g, 5.0 mmol).

EXAMPLE 3 Poly (3-hydroxybutyrate-co-3 -hydroxyvaleriato-co-3-hydroxy-4-methylvaleriato) Poly (3-hydroxybutyrate-co-3-hydroxyvaleriato-co-3-hydroxy-4-methylvaleriato) is prepared following the same procedure used in Example 1, with the exception that what is used as charge monomers is [S] -3-methylpropiolactone (7.20 g, 83.6 mmol), [S] -3-ethylpropiolactone (1.14 g, 11.4 mmol) and [S] -3-isopropylpropiolactone (0.71 g, 5.0 mmol).

EXAMPLE 4 Poly (3-hydroxybutyrate-co-3-hydroxy-4-methylvaleriato-co-3-hydroxyoctanoate) Poly (3-hydroxybutyrate-co-3-hydroxy-4-methylvaleriato-co-3-hydroxyoctanoate) is prepared following the same procedure used in Example 1, with the exception that what is used as charge monomers is [S] -3-methylpropiolactone (9.50 g, 110 mmol), [S] -3-isopropylpropiolactone (0.41 g, 2.9 mmol) and [S] -3-pentylpropiolactone (0.50 g, 2.9 mmol).

P1298 EXAMPLE 5 Poly (3-hydroxybutyrate-co-3-hydroxy-lactone-co-3-hydroxy-4-methyl-lavender-co-3-hydroxyoctanoate) Poly (3-hydroxybutyrate-co-3-hydroxylalkarylate-co-3-hydroxy) -4-methylvaleriato-co-3-hydroxioctanoate) is prepared following the same procedure used in the Example 1, with the exception that what is used as charge monomers is [S] -3-methylpropiolactone (7.20 g, 83. 6 mmol), [S] -3-ethylpropiolactone (1.14 9, 11.4 mmol), [S] -3- isopropylpropiolactone (0.36 g, 2.5 mmol) and [S] -3-pentylpropiolactone (0.43 g, 2.5 mmol).

EXAMPLE 6 Single layer film capable of being transformed into compost Poly (3-hydroxybutyrate-co-3-hydroxy-4-methylvaleriato) copolymer (PHBMV), with a composition of 5 mol% methylvalerate / 95 mol% butyrate, It is introduced in a single screw extruder (Rheomix Model 202) with a screw diameter of 0.75 inches. A spindle with constant taper was used with a ratio of 20: 1 length to diameter and a compression ratio of 3: 1. The temperature of the two heating zones of the extruder barrel was 25 ° C above the melting temperature of the PHVMV. The extruder was equipped with a die of 6 P1298 inches wide and a gap or opening of 0.04 inches. The die was maintained 20 ° C above the melting temperature of PHBMV. The copolymer is melted into the extruder and pumped into the die at the other end of the extruder. The screw speed of the extruder is kept constant at 30 rpm. The copolymer is pushed through the die and collected in a receiving roll (Postex) collection system at a rate that allows crystallization of the polymer to take place before being picked up. The width of these films is nominally 4 inches and the thickness is approximately 0.002 inches.

EXAMPLE 7 Single layer film susceptible to transformation into compost PHBMV films (95: 5) are manufactured by melting the material between Teflon sheets in a Carver press (Fred S. Carver Inc., Menomonee Falls, Wl) at a temperature 20 ° C above the melting temperature. The pressure on the sheets is adjusted to produce films approximately 0.25 mm thick. Afterwards, the films are cooled in an identical manner to room temperature, placing the molds between large aluminum plates (5 kg) and allowing the films to cool to room temperature.

P1298 EXAMPLE 8 Multilayer films susceptible to transformation into compost The PHBMV film sheets can be prepared from the PHBMV (95: 5) and PHBMV (50:50) compositions following the same procedure used in Example 6.

These sheets can then encase or enclose a sheet of a polymer with good oxygen barrier properties, but with a low water vapor transmission rate or a polymeric film that can be soluble in water, such as polyvinyl alcohol ( PVA). The films are placed in the Carver press, stacked in the following order PHBMV (95: 5), PHBMV (50: 50), PVA, PHBMV (50: 50), PHBMV (95: 5). The material is then pressed at a temperature of 5 ° C above the melting temperature of the PHBMV (50: 50), but still below the melting temperature of the PHBMV (95: 5). After compression at 2000 Ib for 30 min, the pressure is removed and the film is cooled to room temperature.

EXAMPLE 9 Disposable diaper capable of being transformed into compost A disposable baby diaper, according to this invention, is made in the following manner. The dimensions listed are for a diaper proposed to be P1298 used by a baby that is within the size range between 6 and 10 kilograms. These dimensions can be proportionally modified for babies of different sizes, or for trousers for incontinent adults, according to common practice. 1. Reinforcement canvas: 0.020 to 0.038 mm film that includes a copolymer of poly (3-hydroxybutyrate-co-3-hydroxy-4-methylvaleriato) 92: 8 (prepared as described in Example 1); with a width of 33 cm at the top and at the base; with a notch inwards on both sides with a width in the center of 28.5 cm and length of 50.2 cm. 2. Top canvas: polypropylene fibers cut to a length, carded and thermally bonded (polypropylene type 151 of Hercules); with a width of 33 cm at the top and at the base; with a notch inwards on both sides to a center width of 28.5 cm and 50.2 cm in length. 3. Absorbent core: includes 28.6 g of cellulose wood pulp and 4.9 g of absorbent material particles (Nippon Shokubai commercial polyacrylate); calendered, with a thickness of 8.4 mm; with a width of 28.6 cm at the top and at the base; with a notch inwards on both sides to a width in the center of 10.2 cm and 44.5 cm in length.

P1298 4. elastic leg bands: four individual rubber strips (2 per side); with a width of 4.77 mm; length of 370 mm and thickness of 0.178 mm (all previous dimensions in relaxed state). The diaper is made in the normal way, placing the core material with the upper canvas on the reinforcement canvas and gluing them. The elastic tapes (designated "internal" and "external", corresponding respectively to the tapes near the core and far away) are stretched approximately to about 50.2 cm and are placed between the upper canvas / reinforcement canvas along the each longitudinal side (2 tapes per side) of the core. The inner ribbons along each side are placed approximately 55 mm from the narrowest part of the core width (measured from the inner edge of the elastic group). This provides a spacer element along each side of the diaper that includes the flexible material of the upper canvas / reinforcement fabric between the inner elastic and the curved edge of the core. The internal tapes are stuck along their length in the stretched state. The external tapes are placed approximately 13 mm from the internal tapes and are glued along their length in the stretched state. The upper canvas / reinforcement canvas assembly is flexible and the P1298 glued tapes are contracted to stretch the sides of the diaper.

EXAMPLE 10 Lightweight pantyhose that can be transformed into compost A lightweight pantyhose suitable for use between menstrual periods includes a pad (surface area 117cm2, air filter SSK 3.0g) containing 1.0 g of particles of absorbent material (commercial polyacrylate, Nippon Shokubai); this pad is interposed between a porous top sheet formed according to U.S. Patent 4,463,045 and a reinforcing sheet that includes a poly (3-hydroxybutyrate-co-3-hydroxy-4-methylvaleriato) 92: 8 copolymer film of 0.03 mm thickness, prepared according to Example 1.

EXAMPLE 11 Sanitary towel capable of being transformed into compost A menstruation product in the form of a sanitary napkin having two wings extending outward from its absorbent core was made using a pad prepared according to Example 10 (surface area of 117 cm 2) SSK air felt of 8.5 g), according to the design of the United States Patent P1298 4,687,478, by Van Tiliburg, August 18, 1987. The materials of the reinforcing canvas and of the upper canvas are the same as those described in Example 10.

EXAMPLE 12 Sheet capable of being transformed into compost The film preparation process of Example 6 was modified by replacing the die in the extruder with a slot die with a thickness of approximately 0.25 cm and a width of 15 cm. The reception after extrusion is achieved by inserting the sheet exiting the extruder between two counter rotating cylinders. In this way, the sheet is pulled from the extruder and cut into sections of 32cm. Sheets of approximately 13 cm wide and 0.18 cm thick are obtained. EXAMPLE 13 Fiber susceptible to transformation into compost A PHBMV composition of 5 mol% methylvalerate / 95 mol% butyrate is fed into a single screw extruder (Rheomix Model 202) with a screw diameter of 0.75 inches. A constant taper spindle having a long 20: 1 ratio to diameter and a compression ratio of 3: 1 is employed. The temperature of the two heating zones of the extruder barrel is 25 ° C above the melting temperature P1298 of the PHBMV. The extruder is equipped with a die with nozzle that has 5 holes with diameters 500 mm. The die is kept at a temperature 20 ° C above the melting temperature of the PHBMV. The polymer is melted inside the extruder and pumped into the die at the other end of the extruder. The spindle speed remains constant at 30 rpm. The polymer is pushed through the die and the extruded molten fibers pass through a region where an air stream is applied in such a way that the polymer fibers elongate and become thinner until they reach a fifth of the diameter of the polymer. the holes (approximately 100 mm). The fibers, they are collected on a cardboard mat or mat. A wide distribution of fiber length up to several cm in length is obtained. The lengths of most of the fibers (more than 50%) are in the range of 1.3 to 15 cm.

EXAMPLE 14 Rigid foam capable of being transformed into compost In the mixing chamber of a Rheomix type 600 melt mixer equipped with laminating plates, a PHBMV (40 g) is charged with the composition of % by mol of methylvaleriate / 95% in mol of butyrate and 4 g of a common foaming agent, p, p'-oxy-bis-benzenesulfonhydrazide. The temperature of the camera Mixed P1298 is heated to a temperature above the melting temperature of the PHBMV, but below the degradation temperature of the foaming agent (158 ° C). After mixing for 10 minutes at 60 rpm, the copolymer mixture is collected and transferred to a hot aluminum vessel and extended in such a way as to result in a mass of approximately 0.5 cm in thickness. The copolymer is then placed in a furnace (National Appliance Company, model 5830) and heated again to the melting temperature of PHBMV and that temperature maintained until the copolymer is completely molten (approximately 5 min). The temperature of the furnace is then raised to 160 ° C, at which temperature the foaming agent degrades and the copolymer begins to foam. At this point the copolymer foam is removed from the oven and placed in a second oven at the temperature of the maximum crystallization rate of the PHBMV (approximately 80 ° C). The copolymer is left in this oven for 6 hours.

EXAMPLE 15 Flexible foam capable of being transformed into compost The same procedure used in Example 14 is used with the following modifications: instead of PHBMV (95: 5), 40 g of the poly (3-hydroxybutyrate-co-3) copolymer are used. -hydroxy-4-methylvaleriato) with a composition of 60 mol% methylvalerate / 40 mol% butyrate (PHBMV (40:60)).

EXAMPLE 16 Molded articles susceptible to transformation into compost Injection molded articles are made using a Mini Max Molder model CS-183 (Custom Scientific Instruments, Whippeny, N.J.). The temperature of the rotor and the stator cup are kept constant 20 ° C above the melting temperature of the polyhydroxyalkanoate used. In the stator cup, approximately 0.5 grams of PHBMV (95: 5) are charged and allowed to melt for 3 minutes. The molten copolymer is mixed radially by raising and lowering the tip of the rotor five times. A steel mold shaped as an exercise weight is sprayed with a thin layer of silicone as a mold release agent. The mold is placed on the mold carrier wheel of the Mini Max Molder and the molten polymer is injected into the mold by the action of the rotor tip. The copolymer is molded into exercise-type pieces of 0.03-inch-thick, 1-inch-long, 0.125-inch-wide half-pieces and 0.25-inches wide at the ends. These molded parts are suitable for mechanical testing.

P1298 EXAMPLE 17 Non-woven fabric susceptible to transformation into compost In a single-screw extruder (Rheomix Model 202, Paramus, NJ) with a 0.75-inch spindle diameter, the Poly (3-hydroxybutyrate-co-3-hydroxy) copolymer is introduced. 4-methylvaleriato) (PHBMV) with a composition of 2 mol% methylvalerate / 98 mol% butyrate. A constant taper spindle having a length to diameter ratio of 20: 1 and a compression ratio of 3: 1 is employed. The temperature of the two heating zones of the extruder barrel is 25 ° C above the melting temperature of the PHBMV. The extruder is provided with a die with nozzle containing 5 holes of 500 mm in diameter. The die is maintained at 20 ° C above the melting temperature of the PHBMV. The polymer is melted inside the extruder and pumped into the die at the other end of the extruder. The spindle speed remains constant at 30 rpm. The polymer is pushed through the die and the extruded molten fibers are passed through a region where an air stream is applied in such a way that the polymer fibers are they lengthen and become thinner to approximately one fifth of the diameter of the holes (approximately 100 mm). The fibers are collected on a cardboard mat. The mat moves in such a way that an area of 10 cm x 10 cm is uniformly covered with fibers. The collection of fibers in the mat continues until there is a cover of approximately 0.5 cm in thickness. A wide distribution of fiber lengths up to several inches in length is obtained. Most fiber lengths (more than 50%) are in the range of 0.5 to 6 inches. The mat is then transferred to a Carver Press (Fred S. Carver Inc., Menomonee Falls, Wl) and pressed at a force of 10001b for 10 minutes at a temperature of 5 ° C below the melting temperature of the PHBMV. The resulting non-woven sheet is removed from the press.

EXAMPLE 18 Elastomer Susceptible to Transform in Compost PHBMV films (70:30) are made by melting the material between Teflon sheets at a temperature of 20 ° C above the melting temperature. The pressure of the sheets is adjusted to produce films approximately 0.5 mm thick. The films are then cooled in an identical manner to room temperature, placing the molds between large aluminum plates (5 kg) and allowing the films to cool to room temperature. The films are left to rest for 2 days, then subsequently cut into strips 10 cm long and 1 cm wide. The strips are then placed in a P1298 Instron Universal Testing Machine (Model 1122, Canton, MA) and stretch or lengthen at a speed of 1 in / min until an elongation of 300% of the original length is achieved. The films remain elongated for two days, until the subsequent crystallization develops. The strips are removed from the Instron apparatus and after the subsequent extension, the material returns to its previous length (post-Instron treatment).

EXAMPLE 19 Adhesives Capable of Transforming into Compost PHBMV (50:50) can be used as a hot melt adhesive in the following manner. Approximately lg of PHBMV (50:50) is placed between two polymer films, such as polyvinyl alcohol (PVA) or poly (3-hydroxybutyrate) (PHB) or any other PHA having a melting temperature of at least 10 ° C higher than the PHBMV (50:50). The film / adhesive assembly is placed in a Carver press (Fred S. Carver Inc., Menomonee Falls, Wl) and then pressed at a temperature 5 ° C above the melting temperature of the PHB: MV (50:50) . After compressing at a force of 2000 Ib for 30 min, the pressure is released and the set of bonded films is allowed to cool to room temperature. All the aforementioned publications P1298 herein are incorporated by reference in their entirety. It is understood that the examples and modalities described here are for illustrative purposes only and that in the light of them, those that dominate the technical field will be suggested several modifications or changes and these will be included in the spirit and scope of this application and in the scope of the claims annexed below.

P1298

Claims

CLAIMS; 1. A biodegradable copolymer that includes at least two randomly repeating monomer units, wherein the first monomeric unit that is randomly repeated has the structure where R1 is H, or C1 or C2 alkyl and n is 1 or 2; the second monomeric unit that repeats randomly has the structure and wherein at least 50% of the monomeric units that are randomly repeated have the structure of the first monomeric unit that is randomly repeated.
2. The biodegradable copolymer according to claim 1, wherein R1 is a C1 or C2 alkyl and n is 1.
3. The biodegradable copolymer according to claim 2, wherein R1 is a Cx alkyl.
4. The biodegradable copolymer according to P1298 claim 1, wherein R1 is H and n is 2.
5. A biodegradable copolymer including at least three randomly repeating monomer units, wherein the first monomeric unit that is randomly repeated has the structure where R1 is H or C1 or C2 alkyl and n is 1 or 2; the second monomeric unit that repeats randomly has the structure the third monomeric unit that repeats randomly has the structure where R3 is H or an alkyl or alkenyl Ci-Cig and m is 1 or 2; where at least 50% of the monomer units that are randomly repeated have the structure of the first P1298 monomeric unit that is randomly repeated and, where, the third monomeric that is randomly repeated is not the same as the first monomeric unit that is randomly repeated or that the second monomeric unit that is randomly repeated.
6. The biodegradable copolymer according to Claim 5, wherein R1 is a C1 or C2 alkyl and n is 1.
7. The biodegradable copolymer according to Claim 6, wherein R1 is a C1 alkyl.
8. The biodegradable copolymer according to claim 6, wherein m is 1.
9. The biodegradable copolymer according to claim 6, wherein m is 2.
10. The biodegradable copolymer according to Claim 5, wherein R1 is H and n is 2.
11. The biodegradable copolymer according to Claim 10, wherein m is 1.
12. The biodegradable copolymer according to Claim 10, wherein m is 2. P1298