RU2575265C2 - Biodegradable films - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to film, which is applied in multitude of disposable products, such as diapers, sanitary napkins, underwear for adults with enuresis, bandages, etc. Biodegradable film contains from approximately 1 wt % to approximately 49 wt % of weight of matrix phase film, containing at least one biodegradable polyester, and from approximately 46 wt % to approximately 75 wt % of weight of dispersed phase film, containing at least one oxidised corn or oxidised wheat starch and at least one plasticiser; where dispersed phase is dispersed in matrix phase, and also where wt % of matrix phase of film weight is lower than wt % of dispersed phase of film weight. Invention also relates to absorbing product, containing biodegradable film in accordance with invention, where absorbing product has body part, which includes liquid-permeable upper coating, in general liquid-impermeable lower coating and absorbing middle part, located between lower coating and upper coating.

EFFECT: film possesses good mechanical properties.

20 cl, 8 dwg, 5 tbl

Description

State of the art

Films are used in a variety of disposable products, such as diapers, sanitary towels, underwear for adults with incontinence, bandages, etc. For example, many sanitary napkins have an adhesive strip on the back of the napkin (the surface of the napkin is opposite to the surface in contact with the body) to fix the napkin to the underwear and holds the napkin in place with respect to the body. Before use, the adhesive strip is protected by a release liner. After removal, the release liner must be discarded. Other examples of films used for disposable underwear include barrier films for adult and female panty liners, outer films for diapers and training pants, and packaging films for packaging disposable underwear. Such films, however, may not be biodegradable. Or, even if such films are biodegradable, they may include large amounts of expensive components that limit their usefulness for disposable products.

Biodegradable films have been prepared that include biodegradable polyesters and thermoplastic starch, but such films typically include more than one polyester than thermoplastic starch to avoid processing problems and / or effectiveness that may arise. However, such films may be too expensive to be used in disposable products, since biodegradable polyester is usually quite expensive.

As such, there is a need for a less expensive and biodegradable film that has mechanical properties suitable for use in disposable products.

SUMMARY OF THE INVENTION

According to one embodiment of the present invention, a biodegradable film is described which comprises from about 1 wt.% To about 49 wt.% By weight of the film or matrix phase, comprising at least one biodegradable polyester and from about 46 wt.% To about 75 wt. % by weight of the film of the dispersed phase containing at least one oxidized starch and at least one plasticizer, where the dispersed phase is dispersed in the matrix phase, and where wt.% of the mass of the film of the matrix phase is less than wt.% of the mass of the film of the dispersed phase.

According to another embodiment of the present invention, an absorbent article is described that includes a base portion that includes a liquid-permeable topcoat, a generally liquid-permeable undercoat, and an absorbent middle located between the bottom and topcoat. The absorbent article also includes a coating film that defines the first surface and the opposite second surface, where the first surface is adjacent to the adhesive applied to the absorbent article. The coating film, the lower coating, or both include a biodegradable film containing from about 1 wt.% To about 49 wt.% By weight of the matrix phase film containing at least one biodegradable polyester, and from about 46 wt.% To about 75 wt. % by weight of the film of the dispersed phase containing at least one oxidized starch and at least one plasticizer, where the dispersed phase is dispersed in the matrix phase, and also where wt.% of the mass of the film of the matrix phase is less than wt.% of the mass of the film of dispersed phase.

According to another embodiment, the biodegradable film comprises from about 1 wt.% To about 49 wt.% By weight of the film of at least one biodegradable polyester and from about 46 wt.% To about 75 wt.% Of the weight of the thermoplastic oxidized starch film, containing at least one oxidized starch and at least one plasticizer, where wt.% by weight of the film of biodegradable polyester is less than wt.% by weight of the film of thermoplastic oxidized starch.

Other characteristics and aspects of the present invention are described in more detail below.

Brief Description of Drawings

A complete and comprehensive description of the present invention, including the best mode of implementation, intended for a person skilled in the art, is presented below in the remainder of the description, which gives links to the accompanying drawings, in which:

Figure 1 is a stylized illustration of one embodiment of a biodegradable film in accordance with this invention.

Figure 2 is a schematic illustration of one embodiment of a method for producing a biodegradable film in accordance with this invention.

Figure 3 is a top view of an absorbent article that can be obtained according to one embodiment of the present invention.

Figure 4 is a graph of the tested module values for various samples of biodegradable films;

Figure 5 is a graph of the tested values of elongation at break for various samples of biodegradable films;

6 is a cross-sectional electron micrograph (SEM) of a biodegradable film;

Figa is an image of a backscattered electron cross-section of another biodegradable film;

Fig.7b is a secondary electronic image of another biodegradable film;

Fig. 8a is a cross-sectional image of a cross-sectional electron of another biodegradable film;

Fig. 8b is a cross-sectional image of an electron cross section in the direction transverse to the processing of another biodegradable film;

Fig. 8c is an image of a backscattered electron of a cross section in the processing direction of another biodegradable film;

The repeated use of reference characters in this description and drawings means the same or similar characteristics or elements in accordance with the invention.

Detailed description of typical options

The following is a detailed description of various embodiments of the present invention, one or more examples of which are presented below. Each example is presented only to explain the invention and does not limit the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made to the invention without departing from the scope or essence of the invention. For example, the characteristics depicted or described as part of one embodiment may be applied in another embodiment to produce another embodiment. Thus, it is intended that the present invention include such modifications and variations as come within the scope of the appended claims and their equivalents.

In general, this invention relates to a film that is biodegradable in that it loses its integrity over time. The film contains a biodegradable polyester, oxidized starch and a plasticizer. The desired film properties can be achieved in accordance with this invention by selectively controlling various aspects of the film production, such as the nature of the components used, the relative amount of each component, the film production method, and so on.

As used herein, the term “biodegradable” refers to a material that decomposes under the influence of natural microorganisms, such as bacteria, fungi and algae; ambient heat; moisture or other environmental factors. Biodegradability of the material can be determined using ASTM Method 5338.92.

1, the film 10 includes a first matrix phase 12 and a second dispersed phase 14. The first matrix phase 12 includes a biodegradable polyester. The second dispersed phase 14 includes plasticized oxidized starch. In certain embodiments, plasticized oxidized starch includes oxidized starch and a plasticizer. Desirably, the matrix phase contains a lower mass percentage of the film than the dispersed phase.

In certain embodiments of the film 10, the dispersed phases 14 may be in the form of highly elongated dispersed structures in the form of plates 16. "Strongly elongated" means that the ratio ("UW") I) is greater than the length of the dispersed structure, measured in the transverse direction or the processing direction (" L ") to ii) the greater thickness of the dispersed structure, measured in the direction of the film thickness (" W ") may vary in some embodiments from about 2 to about 30, in some embodiments from about 5 to about 25, and in some embodiments from about 10 to about 20. The large thickness of the dispersed "W" structures may vary in some embodiments from about 0.01 microns to about 1 microns, in some embodiments from about 0.05 microns to about 0.9 microns, and in some embodiments from about 0.1 microns to about 0.8 microns. The large thickness of the matrix phase between the dispersed structures can vary in some embodiments from about 0.01 microns to about 1 microns, in some embodiments from about 0.05 microns to about 0.9 microns, and in some embodiments from about 0.1 microns to about 0.8 microns. Highly elongated dispersed structures in the form of sheets 16 can be connected by one or more bridges 18, which include plasticized oxidized starch. The structural arrangement mimics a microlayer film laminate in which thin layers of biodegradable polyester are transferred between microlayers of thermoplastic oxidized starch. Without pretending to be a theory, the authors of the present invention believe that the structural arrangement of the phases is important for the good mechanical properties of the film.

In this regard, various variants of the present invention are described in more detail below.

I. Film Components

A. Biodegradable Polyester

The term “biodegradable” generally refers to a material that decomposes under the influence of natural microorganisms, such as bacteria, fungi and algae; ambient heat; moisture or other environmental factors, such as determined according to ASTM Test Method 5338.92. Biodegradable polyesters used in accordance with this invention typically have a sufficiently low glass transition temperature ("T _g ") to reduce film rigidity and improve polymer process characteristics. For example, T _g may be about 25 ° C or less, in some embodiments, about 0 ° C or less, and in some embodiments, about -10 ° C or less. Also, the melting point of biodegradable polyesters is also relatively low to improve biodegradation rate. For example, the melting point is typically from about 50 ° C to about 180 ° C, in some embodiments, from about 80 ° C to about 160 ° C, and in some embodiments, from about 100 ° C to about 140 ° C. . The melting point and glass transition temperature can be determined using differential scanning calorimetry ("DSC") according to ASTM D-3417, and are also known in the art. Such tests can be carried out using the DSC Q100 Differential Scanning Calorimeter (equipped with a liquid nitrogen cooling device) and using the THERMAL ADVANTAGE analytical software (version 4.6.6) available from T.A. Instruments Inc. New Castle, Delaware.

Biodegradable polyesters can also have a number average molecular weight (“M _n ”) of from about 40,000 to about 120,000 grams per mole, in some embodiments, from about 50,000 to about 100,000 grams per mole, and in some embodiments, from about 60,000 to about 85,000 grams per mole.

Also, polyesters can have a weight average molecular weight ("Mw") of from about 70,000 to about 300,000 grams per mole, in some embodiments, from about 80,000 to about 200,000 grams per mole, and in some embodiments, from about 100,000 to about 150,000 grams per mole the mole. The ratio of weight average molecular weight to number average molecular weight (“M _w / M _n ”), i.e., “polydispersity coefficient”, is also relatively low. For example, the polydispersity coefficient is typically from about 1.0 to about 4.0, in some embodiments, from about 1.2 to about 3.0, and in some embodiments, from about 1.4 to about 2.0 . The weight average and number average molecular weights can be determined by methods known to those skilled in the art.

Biodegradable polyesters can also have an apparent viscosity of from about 100 to about 1000 Pascal second (Pa · s), in some embodiments, from about 200 to about 800 Pa · s, and in some embodiments, from about 300 to about 600 Pa · s, determined at a temperature of 170 ° C and a shear rate of 1000 sec ^-1 . The melt flow index of biodegradable polyesters can also vary from about 0.1 to about 30 grams in 10 minutes, in some embodiments, from about 0.5 to about 10 grams in 10 minutes, and in some embodiments, from about 1 to about 5 grams in 10 minutes. The melt flow index is the mass of polymer (in grams) that can be passed under pressure through the hole of the extrusion rheometer (diameter 0.0825 inches) when applying a load of 2160 grams in 10 minutes at a certain temperature (for example, 190 ° C), measured according to ASTM Test Method D1238-E.

Of course, the melt flow index of biodegradable polyesters largely depends on the chosen method of producing the film. For example, when extruding in the form of an irrigation film, a higher polymer melt flow index, such as about 4 grams in 10 minutes or more, in some embodiments, from about 5 to about 12 grams in 10 minutes, and in some embodiments, is generally desirable. , from about 7 to about 9 grams in 10 minutes. Also, when forming in the form of a film obtained by blown extrusion, as a rule, more desirable is the melt flow index of the polymers, such as less than about 12 grams in 10 minutes or less, in some embodiments, from about 1 to about 7 grams in 10 minutes, and in some embodiments, from about 2 to about 5 grams in 10 minutes.

Examples of suitable biodegradable polyesters include aliphatic polyesters such as polycaprolactone, polyester amides, modified polyethylene terephthalate, polylactic acid (PMA) and its copolymers, polylactic acid based terpolymers, polyglycolic acid, polyalkylene carbonates (such as polyethylene carbonate), polyhydroxy poly-3-hydroxybutyrate (PHB), poly-3-hydroxyvalerate (PGV), copolymers of poly-3-hydroxybutyrate-co-4-hydroxybutyrate, poly-3-hydroxybutyrate-co-3-hydroxyvalerate (P BV), poly-3-hydroxybutyrate-co-3-hydroxyhexanoate, poly-3-hydroxybutyrate-co-3-hydroxyoctanoate, poly-3-hydroxybutyrate-co-3-hydroxydecanoate, poly-3-hydroxybutyrate-co-3-hydroxyoctadecanoate and succinate-based aliphatic polymers (for example, polybutylene succinate, polybutylene succinate adipate, polyethylene succinate, etc ..); aromatic polyesters and modified aromatic polyesters; and aliphatic-aromatic copolyesters. In one specific embodiment, the biodegradable polyester is an aliphatic-aromatic copolyester (e.g., block, random, grafted, etc.). The aliphatic-aromatic copolyester can be synthesized using any known method, such as polymerization by condensation of a polyhydric alcohol in combination with aliphatic and aromatic dicarboxylic acids or their anhydrides. Polyhydric alcohols can be substituted or not substituted, linear or branched, polyhydric alcohols selected from polyhydric alcohols containing from 2 to about 12 carbon atoms, and polyalkylene ether glycols containing from 2 to 8 carbon atoms. Examples of polyhydric alcohols that may be used include, but are not limited to, ethylene glycol, diethylene glycol, propylene glycol, 1,2-propanediol, 1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 1,2 -butanediol, 1,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,5-pentanediol, 1,6-hexanediol, polyethylene glycol, diethylene glycol, 2,2,4-trimethyl-1,6-hexanediol , thioethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, cyclopentanediol, triethylene glycol and tetraethylene glycol. Preferred polyols include 1,4-butanediol; 1,3-propanediol; ethylene glycol; 1,6-hexanediol; diethylene glycol; and 1,4-cyclohexanedimethanol.

Typical aliphatic dicarboxylic acids that may be used include substituted or unsubstituted, linear or branched, non-aromatic dicarboxylic acids selected from aliphatic dicarboxylic acids containing from 2 to about 10 carbon atoms, and derivatives thereof. Non-limiting examples of aliphatic dicarboxylic acids include malonic, malic, succinic, oxalic, glutaric, adipic, pimelic, azelaic, sebacic, fumaric, 2,2-dimethylglutaric, suberinic, 1,3-cyclopentanedicarboxylic, 1,4-cyclohexane -cyclohexanedicarboxylic, diglycolic, itaconic, maleic and 2,5-norbornanedicarboxylic acids. Typical aromatic dicarboxylic acids that may be used include substituted or unsubstituted, linear or branched aromatic dicarboxylic acids selected from aromatic dicarboxylic acids containing 8 or more carbon atoms, and derivatives thereof. Non-limiting examples of aromatic dicarboxylic acids include terephthalic acid, dimethyl terephthalate, isophthalic acid, dimethyl isophthalate, 2,6-naphthalenedicarboxylic acid, dimethyl-2,6-naphthalate, 2,7-naphthalenedicarboxylic acid, 3-dimethyl-2,7-naphthalate, 3 dicarboxylic acid 'diphenyl ester, dicyl-3,4'-diphenyl ether dicarboxylate, 4,4'-diphenyl ether dicarboxylic acid, dimethyl-4,4'-diphenyl ether dicarboxylate, 3,4'-diphenyl sulfide dicarboxylic acid, dimethyl-3 4'-diphenyl sulfide dicarboxylate, 4,4'-diphenyl sulfide dicarboxylic acid, dimethyl-4,4'-diphenyl sulfide dicarboxylate, 3,4'-diphenylsulfone dicarboxylic acid, dimethyl-3,4'-diphenylsulfone dicarboxylate, 4,4'-diphenylsulfone dicarboxylic acid, dimethyl-4, 4'-diphenylsulfone dicarboxy , 3,4'-benzophenone dicarboxylic acid, dimethyl-3,4'-benzophenone dicarboxylate, 4,4'-benzophenone dicarboxylic acid, dimethyl-4,4'-benzophenone dicarboxylate, 1,4-naphthalenedicarboxylic acid, dimethyl-1,4-naphthalate, 4,4'-methylene bis (benzoic acid), dimethyl-4,4'-methylenebis (benzoate), etc., and mixtures thereof.

The polymerization can be catalyzed by a catalyst, such as a titanium-based catalyst (for example, tetraisopropyl titanate, tetraisopropoxy titanium, dibutoxyacetoxy titanium or tetrabutyl titanate). If desired, the diisocyanate chain extender will burn to be reacted with the copolyester to increase molecular weight. Typical diisocyanates may include toluene 2,4-diisocyanate, toluene 2,6-diisocyanate, 2,4'-diphenylmethane diisocyanate, naphthylene-1,5-diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate (HMDI), isophorone diisocyanate and methyl 2-isocyanatocyclohexane).

Tri-functional isocyanate compounds that contain isocyanurate and / or hydrazodicarbonamide groups with a functionality of at least three, or to replace diisocyanate compounds with partially tri- or polyisocyanates, can also be used. A preferred diisocyanate is hexamethylene diisocyanate. The amount of chain extender is typically from about 0.3 to about 3.5 wt.%, In some embodiments, from about 0.5 to about 2.5 wt.% With respect to the total weight polymer.

The copolyesters can be either a linear polymer or a long chain branched polymer. Long chain branched polymers are typically prepared using a low molecular weight branching agent, such as polyhydric alcohol, polycarboxylic acid, hydroxy acid, and so on. Typical low molecular weight polyols which can be used as branching agents include glycerin, trimethylolpropane, trimethylol ethane, polyether triols, 1,2,4-butanetriol, pentaerythritol, 1,2,6-hexanetriol, sorbitol, 1,1,4,4 , -tetrakis (hydroxymethyl) cyclohexane, tris (2-hydroxyethyl) isocyanurate and dipentaerythritol. Typical high molecular weight polyhydric alcohols (molecular weight 400 to 3000) that can be used as branching agents include triols obtained by condensation of alkylene oxides having from 2 to 3 carbon atoms, such as ethylene oxide and propylene oxide, with polyhydric alcohol initiators. Typical polycarboxylic acids that can be used as branching agents include hemimellitic acid, trimellitic (1,2,4-benzene-tricarboxylic) acid and anhydride, trimesic (1,3,5-benzene-tricarboxylic) acid, pyromellitic acid and anhydride, benzene tetra-carboxylic acid, benzophenone tetracarboxylic acid, 1,1,2,2-ethynetetracarboxylic acid, 1,1,2-ethanetricarboxylic acid, 1,3,5-pentantricarboxylic acid and 1,2,3,4-cyclopentantetracarboxylic acid. Typical hydroxy acids that can be used as branching agents include malic acid, citric acid, tartaric acid, 3-hydroxyglutaric acid, mucus acid, trihydroxyglutaric acid, 4-carboxyphthalic anhydride, hydroxyisophthalic acid and 4- (beta-hydroxyethyl). Such hydroxy acids contain a combination of 3 or more hydroxyl and carboxyl groups. Particularly preferred branching agents include trimellitic acid, trimesic acid, pentaerythritol, trimethylolopropane and 1,2,4-butanetriol.

The monomer component of the aromatic dicarboxylic acid may be present in the copolyester in an amount of from about 10% mol to about 40% mol, in some embodiments, from about 15% mol to about 35% mol, and in some embodiments, from about 15% mol to about 30% mol. The monomer component of the aliphatic dicarboxylic acid may also be present in the copolyester in an amount of from about 15% mol to about 45% mol, in some embodiments, from about 20% mol to about 40% mol, and in some embodiments, from about 25% mol to about 35% mol. The polyhydric monomer moiety may also be present in the aliphatic-aromatic polyester in an amount of from about 30% mol to about 65% mol, in some embodiments, from about 40% mol to about 50% mol, and in some embodiments, from about 45% mol up to about 55% mol.

In one specific embodiment, for example, an aliphatic-aromatic complex copolyester may contain the following structure:

Where,

m is an integer from 2 to 10, in some embodiments, from 2 to 4, and in one embodiment, 4;

n is an integer from 0 to 18, in some embodiments, from 2 to 4, and in one embodiment, 4;

p is an integer from 2 to 10, in some embodiments, from 2 to 4, and in one embodiment, 4;

x is an integer greater than 1; and

y is an integer of more than 1. One example of such a copolyester is polybutylene adipate terephthalate, which is commercially available under the name ECOFLEX® F BX 7011 from BASF Corp. Another example of a suitable copolyester containing aromatic terephthalic acid monomer is available under the name ENPOL ™ 8060M from IRE Chemicals (South Korea). Other suitable aliphatic-aromatic ester copolymers may be described in US Pat. Nos. 5,292,783; 5,446,079; 5,559,171; 5,580,911; 5,599,858; 5,817,721; 5,900,322; and 6,258,924, which are fully incorporated herein by reference for all purposes.

B. Oxidized starch

Also used is oxidized starch, which is biodegradable in that it contains one or more oxidized starches, which are typically biodegradable. Starch is a natural polymer consisting of amylose and amylopectin. Amylose is an almost linear polymer having a molecular weight in the range of 100,000-500,000, where amylopectin is a highly branched polymer having a molecular weight of up to several million. Although starch is produced in many plants, typical sources include seeds of cereals such as corn, waxy corn, wheat, sorghum, rice and waxy rice; tubers such as potatoes; roots such as tapioca (i.e. cassava and cassava), sweet potatoes and arrowroot; and the core of the sago palm. In general, any natural (unmodified) and / or modified starch can be oxidized for use in accordance with this invention. Starch can be oxidized by treating starch with oxidizing agents. These oxidizing agents include, but are not limited to, hydrochloric acid, sodium hypochlorite, calcium hypochlorite, and so on.

The chemical oxidation of starch changes hydrogen bonds by the creation of carbonyl and carboxyl functional groups on the main chain of starch. Even if the oxidation of starch takes place at a low intensity, it is expected to improve the interaction with synthetic polymers, especially with aliphatic and aromatic complex copolyesters, due to molecular structural (polar) similarities in carbonyl or carboxyl and repeating glucose units and ester groups in complex copolyesters. The aggregation in the product in the mixture is significantly reduced as a result of better interfacial adhesion through polar interactions between the carboxyl and carbonyl groups with oxidized starch, and the polar ester group with copolyesters. Carbonyl and carboxyl groups can also give a low level of crosslinking, which also improves the mechanical efficiency of the mixture even at high levels of TPOS incorporation.

Modified starches, which are chemically modified by other standard methods known in the art (e.g., esterification, esterification, acid hydrolysis, enzymatic hydrolysis, etc.), are often used for oxidation. Ethers and / or esters of starches are particularly desirable, such as hydroxyalkyl starches, carboxymethyl starches, etc. The hydroxyalkyl group of hydroxyalkyl starches may contain, for example, from 2 to 10 carbon atoms, in some embodiments, from 2 to 6 carbon atoms, and in some embodiments, from 2 to 4 carbon atoms.

Typical hydroxyalkyl starches, such as hydroxyethyl starch, hydroxypropyl starch, hydroxybutyl starch and derivatives thereof. Starch esters, for example, can be prepared using a variety of anhydrides (e.g., bite, propionic, butyric, etc.), organic acids, acid chlorides, or other esterification reagents. The degree of esterification can vary as desired, for example, from 1 to 3 ester groups per glycosidic unit of starch.

C. Plasticizer

A plasticizer is also used in films in order to preserve the technological properties of the melt of biodegradable polyester and / or starch. Starches, for example, typically exist in the form of granules that have a coating or an outer membrane that encapsulates a larger number of amylose and amylopectin chains within the granule. When heated, plasticizers (for example, polar solvents) can soften and penetrate through the outer membrane and cause absorption of water starch by the internal chains, followed by swelling. Such swelling, at some point, causes the outer shell to rupture and causes irreversible degradation of the starch granule. After degradation, the polymer chains of starch containing amylose and amylopectin polymers, which are initially compressed inside the granules, will stretch and form, as a rule, a random interweaving of polymer chains. After returning to the solid state, the chains can reorient to obtain crystalline or amorphous solids having different strengths depending on the orientation of the polymer chains of starch. Since starch (natural or modified) is capable of melting and re-hardening, it is generally considered to be "thermoplastic starch."

Suitable plasticizers may include, for example, plasticizers based on polyhydric alcohols such as sugars (e.g. glucose, sucrose, fructose, raffinose, maltodextrose, galactose, xylose, maltose, lactose, mannose and erythrosis), sugar alcohols (e.g. erythritol, xylitol , maltol, mannitol and sorbitol), polyhydric alcohols (e.g. ethylene glycol, glycerin, propylene glycol, dipropylene glycol, butylene glycol and hexantriol), etc. Also suitable are organic compounds forming hydrogen bonds that do not contain hydroxyl groups, including urea and urea derivatives; sugar alcohol anhydrides such as sorbitan; animal proteins such as gelatin; vegetable proteins such as sunflower protein, soy protein, cottonseed protein, and mixtures thereof. Other suitable plasticizers may include phthalate esters, dimethyl and diethyl succinate and related esters, glycerol triacetate, glycerol mono- and diacetates, glycerol mono-, di- and tripropionates, butanoates, stearates, lactic esters, adipic acid esters, esters stearic acid esters, oleic acid esters and other acid esters. Aliphatic acids such as ethyleneactic acid, ethylene maleic acid, butadiene acrylic acid, butadiene maleic acid, propylene acrylic acid, propylene maleic acid and other hydrocarbon-based acids may also be used. A low molecular weight plasticizer is preferred, such as less than about 20,000 g / mol, preferably less than about 5,000 g / mol, and more preferably less than about 1,000 g / mol.

The plasticizer can be introduced into the film using any of a variety of known techniques. For example, starch may be “pre-plasticized” prior to incorporation into the film. Alternatively, one or more of the components may be plasticized simultaneously with mixing. Regardless, a batch and / or continuous melt blending technique may be used to mix the components. For example, a mixer / plasticizer, a Banbury mixer, a continuous Farrel mixer, a single screw extruder, a two screw extruder, a roller mill, etc. may be used. One particularly suitable melt mixing device is a simultaneously rotating two-screw extruder (e.g., the USALAB two-screw extruder, available from Thermo Electron Corporation of Stone, England or an extruder from Werner-Pfreiderer from Ramsey, New Jersey). Such extruders may include ports for loading and ventilation and provide high intensity distribution and dispersion mixing. For example, a starch composition may first be loaded into a port for loading a two-screw extruder.

The plasticizer can then be injected into the starch composition. Alternatively, the starch composition may be simultaneously loaded into the extruder loading opening or separately into various openings along its length. Melt mixing occurs at a variety of temperatures, such as from about 30 ° C to about 200 ° C, in some embodiments, from about 40 ° C to about 160 ° C, and in some embodiments, from about 50 ° C to about 150 ° FROM.

The amount of biodegradable polyester, oxidized starch and plasticizer used in the film is controlled in this invention to achieve the desired balance between biodegradability and mechanical strength. For example, biodegradable polyesters typically comprise from about 1 wt.% To about 49 wt.%, In some embodiments, from about 10 wt.% To about 46 wt.%, And in some embodiments, from about 20 to about. 43 wt.% Film. Plasticizers can comprise from about 0.1 wt.% To about 40 wt.%, In some embodiments, from about 1 wt.% To about 35 wt.%, And in some embodiments, from about 5 to about 30 wt.% Of the film . Further, the oxidized starches can be from about 45 wt.% To about 75 wt.%, In some embodiments, from about 45 wt.% To about 65 wt.%, In some embodiments, from about 45 wt.% To about 55%. wt., in some embodiments, from about 47 wt.% to about 75 wt.%, in some embodiments, from about 47 wt.% to about 65 wt.%, in some embodiments, from about 47 wt.% to about 55 % wt., in some embodiments, from about 50 wt.% to about 75 wt.%, in some embodiments, from about 50 wt.% to about 65 wt.%, and in some embodiments, from about 50 wt.% to about 55 wt.% film. It should be understood that the mass of oxidized starch indicated herein includes all bound water that is naturally present in the oxidized starch before mixing with other components. Oxidized starches, for example, typically contain bound water in an amount of from about 5% to about 16% by weight of starch.

In some embodiments, the oxidized starch and plasticizer are separately dispersively mixed to produce thermoplastic oxidized starch. Thermoplastic oxidized starch can be from about 46 wt.% To about 75 wt.%, In some embodiments, from about 50 wt.% To about 70 wt.%, In some embodiments, from about 50 wt.% To about 65 wt.%. , in some embodiments, from about 55 wt.% to about 70 wt.%, and in some embodiments, from about 55 wt.% to about 65 wt.% of the film.

D. Other components

In addition to the above components, other additives can be included in the film in accordance with this invention, such as dispersion additives, melting stabilizers, process stabilizers, heat stabilizers, light stabilizers, antioxidants, heat aging stabilizers, bleaches, anti-blocking agents, binding agents, lubricants, water soluble polymers, fillers, etc. Dispersion additives, for example, can also be used to obtain a uniform dispersion of a mixture of starch / polyvinyl alcohol / plasticizer and slows down or prevents the separation into constituent phases. Also, the dispersion additive can improve the dispersibility of the film. When used, the dispersion additive, as a rule, is from about 0.01 wt.% To about 15 wt.%, In some embodiments, from about 0.1 wt.% To about 10 wt.%, And in some embodiments, from about 0.5 wt.% to about 5 wt.% film. Although any dispersion additive can be used in accordance with this invention, surfactants having a specific hydrophilic / lipophilic balance (“HLB”) can improve the long-term stability of the composition. HLB is well known in the art and has a scale that measures the balance between the hydrophilic and lipophilic trends of a compound solution. The HLB scale ranges from 1 to about 50, where lower values indicate a significant lipophilic tendency, and higher values indicate a significant hydrophilic tendency. In some embodiments of the invention, the HLB value of the surfactant is from about 1 to about 20, in some embodiments, from about 1 to about 15, and in some embodiments, from about 2 to about 10. If desired, two or more surfactants can be used. -active substances whose HLB values are either lower or higher than the desired value, but together they have an average HLB value in the desired range.

One particularly preferred class of surfactants for use in accordance with this invention are nonionic surfactants, which typically have a hydrophobic base (e.g., a long chain alkyl group or an alkyl aryl group) and a hydrophilic chain (e.g., a chain containing ethoxy and / or propoxy groups). For example, some suitable non-ionic surfactants that may be used include, but are not limited to, ethoxylated alkyl phenols, ethoxylated and propoxylated fatty alcohols, polyethylene glycol ethers of methyl glucose, polyethylene glycol ethers of sorbitol, ethylene oxide-propylene oxide copolymers, ethoxylated esters fatty (C ₈ -C ₁₈ ) acids, condensation products of ethylene oxide with long chain amines or amides, condensation products of ethylene oxide with alcohols, complex fatty acid calves, monoglycerides or diglycerides of long chain alcohols, and mixtures thereof. In one specific embodiment, the nonionic surfactant may be a fatty acid ester such as sucrose fatty acid ester, fatty acid glycerol ester, fatty acid propylene glycol ester, fatty acid sorbitan ester, fatty acid pentaerythritol ester, ether sorbitol fatty acid, and so on. The fatty acid used to produce such esters may be saturated or unsaturated, substituted or unsubstituted, and may contain from 6 to 22 carbon atoms, in some embodiments, from 8 to 18 carbon atoms, and in some embodiments, from 12 to 14 carbon atoms. In one specific embodiment, mono- and diglycerides of fatty acids can be used in accordance with the invention.

One or more water soluble polymers can also be used in accordance with this invention. Water-soluble polymers can comprise from about 0.1 wt.% To about 40 wt.%, In some embodiments, from about 1 wt.% To about 35 wt.%, And in some embodiments, from about 5 to about 30 wt. .% film. Without pretending to be a theory, the authors of the present invention believe that such polymers can improve the compatibility of starch and biodegradable polyester, which gives a film showing excellent mechanical and physical properties during use. Such polymers can be prepared from monomers such as vinyl pyrrolidone, hydroxyethyl acrylate or methacrylate (e.g. 2-hydroxyethyl methacrylate), hydroxypropyl acrylate or methacrylate, acrylic or methacrylic acid, acrylic or methacrylic esters of vinyl pyridine, acrylamide, vinyl alcohol, vinyl acetate, vinyl acetate, vinyl acetate derivatives and so on. Other examples of suitable monomers are described in US Pat. No. 4,499,154 to James, et al., Which incorporated soda in its entirety by reference for all purposes. The resulting polymers can be homopolymers or interpolymers (e.g., copolymer, terpolymer, etc.), and can be non-ionic, anionic, cationic or amphoteric. In addition, the polymer may be of the same type (i.e., homogeneous) or a mixture of different polymers (i.e., heterogeneous).

In one specific embodiment, the water-soluble polymer may contain a repeating unit having a hydroxyl functional group such as polyvinyl alcohol (“PVOH”), polyvinyl alcohol copolymers (eg, ethylene vinyl alcohol copolymers, methyl methacrylate vinyl alcohol copolymers, etc.), and etc. Polymers of vinyl alcohol, for example, contain at least two or more units of vinyl alcohol in the molecule, and can be a homopolymer of vinyl alcohol or a copolymer containing other monomer units. Vinyl alcohol homopolymers can be prepared by hydrolysis of a vinyl ether polymer such as vinyl formate, vinyl acetate, vinyl propionate, etc. Vinyl alcohol copolymers can be prepared by hydrolysis of a vinyl ester copolymer with an olefin containing from 2 to 30 carbon atoms, such as ethylene, propylene, 1-butene, etc .; unsaturated carboxylic acid containing from 3 to 30 carbon atoms, such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, etc., or its ester, salt, anhydride or amide; unsaturated nitrile containing from 3 to 30 carbon atoms, such as acrylonitrile, methacrylonitrile, etc .; simple vinyl ether containing from 3 to 30 carbon atoms, such as methyl vinyl ether, ethyl vinyl ether, etc .; and so on. The degree of hydrolysis can be selected to optimize solubility, etc. polymer. For example, the degree of hydrolysis may be from about 60% mol to about 95% mol, in some embodiments, from about 80% mol to about 90% mol, and in some embodiments, from about 85% mol to about 89% mol. Examples of suitable partially hydrolyzed polyvinyl alcohol polymers are available under the name CELVOL ™ 203, 205, 502, 504, 508, 513, 518, 523, 530 or 540 from Celanese Corp. Other suitable partially hydrolyzed polyvinyl alcohol polymers are available under the name ELVANOL ™ 50 -14, 50-26, 50-42, 51-03, 51-04, 51-05, 51-08 and 52-22 from DuPont

Fillers can also be used in accordance with this invention. Fillers are particles or other forms of material that can be added to the polymer mixture for film extrusion, and which do not chemically interact with the extruded film, but can be uniformly dispersed in the film. Fillers can serve many purposes, including improving film opacity and / or “breathing” (ie, vapor permeability and liquid impermeability). For example, filler films can be made “breathable” by stretching, which causes the polymer to tear away from the filler to form microporous passages. Breathable microporous elastic films are described, for example, in US Pat. Nos. 5,997,981; 6,015,764; and 6.111.163 McCormack. etal .: 5.932.497 Morman. et al .: 6.461.457 Tavlor. etal .. which included soda in its entirety as a reference for all purposes. Furthermore, hindered phenols are typically used as an antioxidant in film production. Some suitable hindered phenols include phenols from Ciba Specialty Chemicals, available under the trade name "Irganox®", such as Irganox® 1076, 1010 or E 201. Moreover, binding agents can also be added to the film to enhance the binding of the film to additional materials ( for example, nonwoven fibers). Examples of such binding agents include hydrogenated hydrocarbon resins. Other suitable binding agents are described in US Pat. Nos. 4,789,699 to Kieffer et al. and 5,695,868 McCormack. which incorporated soda in its entirety as a reference for all purposes.

II. Film production

The film in accordance with this invention may be single or multilayer. Multilayer films can be obtained by co-extrusion of layers, an extrusion coating, or any conventional method of applying layers. Such multilayer films typically contain at least one base layer and at least one surface layer, but may contain any desired number of layers. For example, a multilayer film can be obtained from a base layer and one or more surface layers, where the base layer is obtained from a mixture of biodegradable polyester, starch and plasticizer. In most embodiments, the surface layer (s) are made from a biodegradable polyester, thermoplastic starch, and a plasticizer, as described above. It should be understood, however, that other polymers can also be used in the surface layer (s), such as polyolefin polymers (e.g., linear low density polyethylene (LDL) or polypropylene). The term “linear low density polyethylene” refers to polymers of ethylene and higher alpha olefin comonomers, such as C ₃ -C ₁₂ and combinations thereof, having a melting point (measured by ASTM D-1238) of from about 0.5 to about 30 grams per 10 minutes at 190 ° C. Examples of predominantly linear polyolefin polymers include, without limitation, polymers derived from the following monomers: ethylene, propylene, 1-butene, 4-methylpentene, 1-hexene, 1-octene and higher olefins, as well as copolymers of ethylene and other olefins, including butene , 4-methylpentene, hexene, heptene, octene, decene, etc. are also examples of predominantly linear polyolefin polymers. Additional film-forming polymers that are suitable for use in accordance with this invention, alone or in combination with other polymers, include ethylene vinyl acetate, ethylene ethacrylate, ethylene acrylic acid, ethylene methyl acrylate, ethylene n-butyl acrylate, nylon, ethylene vinyl alcohol, polystyrene, polyurethane and the like. Further.

Any known technique can be used to produce a film of mixed material, including blowing, casting, extruding from a flat head, etc. In one specific embodiment, the film can be obtained by the method of blowing, in which gas (for example, air) is used to inflate the extruded polymer mixture through a round head. The bubble then collapses and collects in a flat film. Methods for producing a blown film are described, for example, in US Pat. Nos. 3,354,506 to Ralev: 3,650,649 Schippers: and 3,801,429 to Schrenk et al., As well as in patent application publications No. 2005/0245162 McCormack. et al. and 2003/0068951 Boaqs. et al., all of which are incorporated herein by reference in their entireties. In yet another embodiment, however, the film is produced using a casting technique.

According to FIG. 2, for example, one embodiment of a method for producing a film by casting is shown. The feedstock (e.g., biodegradable polyester, oxidized starch, plasticizer, etc.) can be supplied to melt mixing devices, either individually or in the form of one or more mixtures. In one embodiment, for example, oxidized starch and plasticizer are separately fed to melt mixing devices, where they are dispersedly mixed as described above to produce thermoplastic oxidized starch. For example, an extruder may be used that includes ports for loading and venting. In one embodiment, the biodegradable polyester may be fed to the port for loading the twin-screw extruder and melted. Then, the thermoplastic oxidized starch can be fed into the polymer melt. Regardless, the materials are mixed with high shear / pressure and heated for sufficient mixing. For example, melt mixing may occur at a temperature of from about 50 ° C to about 300 ° C, in some embodiments, from about 70 ° C to about 250 ° C, and in some embodiments, from about 90 ° C to about 180 ° C .

Also, the apparent shear rate during melt mixing may vary from about 100 seconds ^-1 to about 10,000 seconds ^-1 , in some embodiments, from about 500 seconds ^-1 to about 5000 seconds ^-1 , and in some embodiments, from about 800 seconds ^-1 to about 1200 seconds ^-1 . The apparent shear rate is 4Q / πR ³ , where Q is the volumetric flow rate ("m ³ / s") of the polymer melt and R is the radius ("m") of the capillary (eg, extruder head) through which the molten polymer flows.

Then the extruded material can be immediately cooled and cut into granules. In a specific embodiment of FIG. 2, a mixed material (not shown) is then fed into an extrusion apparatus 80 and poured onto a spreading roller 90 to form a single layer film precursor 10a. If a multilayer film is produced, a plurality of layers are coextruded together onto the applicator roller 90. The applicator roller 90 may optionally be equipped with embossing elements to provide a template for the film. Typically, the application roller 90 is maintained at a temperature sufficient to cure and harden the sheet 10a during its formation, for example, from about 20 to 60 ° C. If desired, a vacuum box may be positioned adjacent to the applicator roller 90 to hold the film precursor 10a close to the surface of the roller 90. Additionally, air knives or electrostatic knives to remove unevenness can help advance the film precursor 10a over the surface of the applicator roller 90 when it movement around a rotating roller. An air knife is a device known in the art that focuses the air flow at a very high flow rate to pin the edges of the film.

After casting, the film 10a may optionally be oriented in one or more directions to further improve film uniformity and reduce thickness. Orientation can also form micropores in the film containing the filler, providing “breathing” of the film. For example, a film can be immediately reheated to a temperature below the melting temperature of one or more polymers in the film, but high enough to stretch or stretch the film. In the case of sequential orientation, the “softened” film is pulled on rolls rotating at different speeds of rotation so that the sheet is stretched to the desired degree of stretching in the longitudinal direction (processing direction). Such a “uniaxially” oriented film can then be laminated to the fibrous film. In addition, the uniaxially oriented film can be oriented in the direction transverse to the processing to obtain a "biaxially oriented" film. For example, the film can be clamped at the lateral ends with chain clips and transferred to a drying oven. In a drying oven, the film can be reheated and stretched in the direction across the processing to the desired degree of drawing with chain clamps diverging in the forward direction.

Again, according to FIG. 2, for example, showing one method for producing a uniaxially oriented film. As shown, the film precursor 10a is directed to a film orientation device 100 or a machining direction reference (“ITO”), such as is available from Marshall and Willams, Co. of Providence, Rhode Island. IT has a plurality of tensile rolls (such as 5-8) that progressively stretch and thin the film in the processing direction, which is the direction of movement of the film in the process, as shown in FIG. 2. Although ITO 100 is shown with eight rolls, it should be understood that the number of rolls may be higher or lower, depending on the desired level of stretching and the degree of stretching between each roll. The film may be stretched by one or many separate stretching operations. It should be noted that the rolls in the unit IT may not have the ability to work at a gradually increasing speed. If desired, some of the rollers OHO 100 can act as preheated rolls. If present, these first few rolls heat the film 10a to a temperature above room temperature (e.g., to 125 ° F). Gradually increasing speeds of adjacent rolls in IT help stretch the film 10a. The speed at which the stretching rolls rotate determines the degree of stretching of the film and the final mass of the film.

The resulting film 10b can then be wound and stored on the take-up cylinder 60. Although not shown, various additional processing and / or finishing steps known in the art, such as cutting, cleaning, hole making, printing, or layering the film of other layers (for example, non-woven fabric) can be carried out without departing from the essence and scope of the present invention.

The thickness of the resulting biodegradable film, as a rule, varies depending on the intended application. However, the film thickness is generally minimized to reduce the time required for the biological degradation of the film. Thus, in most embodiments of the invention, the biodegradable film has a thickness of about 50 micrometers or less, in some embodiments, from about 1 to about 40 micrometers, in some embodiments, from about 2 to about 35 micrometers, and in some embodiments, from about 5 up to about 30 micrometers.

Despite such a small thickness, the film in accordance with this invention is able to maintain good dry mechanical properties during use. One of the parameters showing good dry film strength is the ultimate tensile strength, which is equal to the peak tension obtained in the stress-strain curve. It is desirable that the film in accordance with this invention has an ultimate tensile strength in the processing direction ("BUT") from about 10 to about 80 megapascals (MPa), in some embodiments, from about 10 to about 60 MPa, and in some embodiments, from about 10 to about 50 MPa, and an ultimate tensile strength in the direction across the processing (“PO”) from about 2 to about 40 Megapascals (MPa), in some embodiments, from about 4 to about 40 MPa, and in some embodiments, from about 5 to about 30 MPa. Although it should have good strength, it is also desirable that the film e be too hard. One of the parameters that are an indicator of the relative stiffness of the film (in the dry state) is Young's modulus of elasticity, which is equal to the ratio of tensile stress to relative elongation and is determined by the slope of the stress-strain curve. For example, a film typically has a Young's modulus in the processing direction (“BUT”) of from about 50 to about 200 Megapascals (“MPa”), in some embodiments, from about 50 to about 100 MPa, and in some embodiments, from about 60 to about 80 MPa, and the Young's modulus in the direction across the processing ("PO") from about 50 to about 200 Megapascals ("MPa"), in some embodiments, from about 50 to about 100 MPa, and in some embodiments, from about 60 to about 80 MPa. The elongation of the HO and the film, respectively, can also be about 100% or more, in some embodiments, about 200% or more, and in some embodiments, about 300% or more, in some embodiments about 400% or more, and in some options of about 500% or more.

III. Products

The biodegradable film in accordance with this invention can be used in many fields. For example, as indicated above, the film may be used in an absorbent article. An “absorbent article” generally refers to any article capable of absorbing water or other liquids. Examples of some absorbent products include, but are not limited to, personal care absorbent products such as diapers, training pants, absorbent pants, urinary incontinence products, feminine hygiene products (e.g., sanitary napkins, daily towels, etc.), swimming clothes, baby wipes, and so on; medical absorbent products such as clothing, garments, sheets with a dedicated surgical field, absorbent sheets, sheets, bandages, absorbent wipes and medical wipes; table napkins; items of clothing; and so on. Some examples of such absorbent articles are described in US Pat. Nos. 5,649,916 to DiPalma. et al .: 6,110,158 Kielpikowski: 6,663,611 Blanev. et al., which are incorporated herein in their entirety by reference for all purposes. Other suitable products are described in U.S. Patent Application Publication No. 2004/0060112 A1 to Fell et al. as well as in US Pat. Materials and methods suitable for preparing such absorbent articles are well known to those skilled in the art.

As is well known in the art, the absorbent article may have an adhesive layer (eg, pressure sensitive adhesive) that helps to removeably hold the article in the crotch area of the underwear and / or the article wrapped for disposal. Suitable pressure-sensitive adhesives, for example, may include acrylic adhesives, natural rubber adhesives, high-adhesive block copolymers, polyvinyl acetate adhesives, ethylene vinyl acetate adhesives, pressure sensitive adhesives or polyurethane adhesives, thermal adhesives epoxy-based polyester, etc. Such pressure sensitive adhesives are known in the art and are described in Handbook of Pressure Sensitive Adhesive Technology, Satas (Donatas), 1989, 2 ^nd edition, Van Nostrand Reinhold. Pressure sensitive adhesives may also include additives such as crosslinking agents, fillers, gases, blowing agents, glass or polymer microspheres, silicon dioxide, calcium carbonate fibers, surfactants, and so on. Additives are included in amounts sufficient to achieve the desired properties.

The location of the adhesive on the absorbent article is not critical and can vary widely depending on the intended use of the article. For example, certain feminine hygiene products (eg, sanitary napkins) may have wings or lapels that are located on the sides of the central absorbent core and are designed to fold around the edges of the consumer’s panties in the crotch area. Lapels can have an adhesive layer (for example, pressure sensitive adhesive) for fastening lapels on the underside of a consumer’s panties.

Regardless of the specific location of the adhesive, however, a coating film can be used to coat the adhesive, protecting it from dirt, drying and sticking before use. The coating film may contain a removable coating, which improves the ability to tear from the adhesive. The removable coating contains a release agent, such as a hydrophobic polymer. Examples of hydrophobic polymers include, for example, silicones (e.g. polysiloxanes, epoxy silicones, etc.), perfluoroethers, fluorocarbons, polyurethanes and so on. Examples of such release agents are described, for example, in US Pat. Nos. 6,530,910 to Pomplun. et al .; 5.985.396 Kerins. et al .: and 5,981,012 Pomplun. et al., which are incorporated herein in their entirety by reference for all purposes. One of the most suitable release agents is an amorphous polyolefin having a melt viscosity of from about 400 to about 10,000 cps at 190 ° C., for example, manufactured by U.S. Rexene Company under the trade name REXTAC® (e.g. RT2315, RT2535 and RT2330). The removable coating may also contain a viscosity reducing agent, such as a low molecular weight, highly branched polyolefin. A particularly suitable low molecular weight, highly branched polyolefin is VYBAR® 253 manufactured by Petrolite Corporation. Other additives may also be used in the removable coating, such as compatibilizing agents, processing aids, plasticizers, tackifiers, friction reducing agents and antimicrobial agents, and so on. The removable coating may be applied to one or both surfaces of the gasket, and may cover all or only part of the surface. Any suitable technique can be used to apply a removable coating, such as a solvent-based coating, a hot melt coating, a solvent-free coating, etc. Solvent-based coatings are typically applied to the coating film by methods such as roller application, knife application, bulk application, gravure printing, plank application, and so on. The solvent (eg, water) is then removed by drying in an oven, and the coating is optionally cured in an oven. Solvent-free coatings may include solid compositions, such as silicones or epoxysilicones, which are applied to the pad and then cured in ultraviolet light. Optional steps include priming the gasket before coating or modifying the surface of the gasket, such as corona treatment. Hot melt coatings, such as polyethylenes or perfluoroethers, can be heated and then applied through a hole or with a heated knife. Hot melt coatings can be applied by co-extruding the release agent with a release liner in an extruder to form a swollen film or sheet to facilitate coating and processing efficiency.

To improve the ability to easily recycle, various components of the absorbent product can be obtained from a biodegradable film in accordance with this invention. For example, films obtained from a biodegradable film in accordance with this invention can be used as a membrane (lower coating) film for adult and female pads and napkins, an outer film for diapers and training pants, a packaging film for bags containing disposable underwear, and etc. In this regard, one of the specific options for sanitary napkins in which the biodegradable film in accordance with this invention can be used is described in more detail. For illustrative purposes only, the absorbent article 20 is shown in FIG. 3 as a sanitary napkin for feminine hygiene. However, as indicated above, this invention can be embodied in other types of absorbent articles, such as incontinence articles, diapers, diaper pants, training pants for children, and so on. In the illustrated embodiment, the absorbent article 20 includes a body portion to the body 22 comprising an upper coating 40, an outer coating or lower coating 42, an absorbent middle 44 located between the lower coating 42 and the upper coating 40, and a pair of lapels 24 extending from each longitudinal side 22a of the main part to the body 22. The upper coating 40 defines the surface of the absorbent article 20 adjacent to the body. The absorbent middle 44 is located inward from the outer periphery of the absorbent article 20 and includes an adjacent to the body thoron adjacent the topsheet 40 and adjacent to the garment surface adjacent the backsheet 42.

Topcoat 40 is typically designed to contact the wearer's body and be permeable to liquid. The top cover 40 may surround the absorbent core 44 so as to completely accommodate the absorbent article 20. Alternatively, the top cover 40 and the bottom cover 42 may be located outside the absorbent middle 44 and connected at the edges, in whole or in part, using conventional methods. Typically, topcoat 40 and bottomcoat 42 are coupled by adhesive bonding, ultrasonic bonding, or any other suitable method known in the art. The topcoat 40 is sanitary, clean and partially opaque in order to obscure the body secretions collected and absorbed by the absorbent medium 44. The topcoat 40 also exhibits good penetration and rewet characteristics that allow the body secretions to quickly penetrate the topcoat 40 into the absorbent middle 44. but not allowing body fluids to flow through the top cover 40 onto the wearer's skin. For example, some suitable materials that can be used for topcoat 40 include non-woven materials, perforated thermoplastic films, or combinations thereof. A nonwoven fabric is made from polyester, polyethylene, polypropylene, bicomponent fibers, nylon, acetate silk, or similar fibers. For example, a white uniform spanbond is especially desirable since the color provides good masking properties to hide the periods that pass it. U.S. Patent No. 4,801,494 to Datta. et al. and U.S. Patent No. 4,908,026 to Sukiennik. et al. various other coating materials that can be used in accordance with this invention are described.

The top cover 40 may also contain a plurality of through holes (not shown) allowing body fluids to more easily pass into the absorbent core 44. The holes may be derivatively or uniformly located on the top cover 40, or they may only be located on a narrow longitudinal strip or tape, located along the longitudinal axis X-X of the absorbent article 20. The holes allow the body fluid to quickly penetrate the absorbent core 44. The size, shape, diameter and number of holes may vary depending on and on the specific needs.

As indicated above, the absorbent article also includes a lower coating 42. The lower coating 42, which can also be obtained in accordance with this invention, is generally impervious to liquid and adheres to the inner surface, that is, the crotch area of the underwear (not shown) . The bottom cover 42 allows air or steam to pass from the absorbent article 20, while blocking the passage of liquid. Typically, any liquid impervious material may be used to provide a lower coating 42. For example, one suitable material that may be used is a microperforated biodegradable film in accordance with this invention. In particular embodiments, a film is used that has a thickness of from about 0.2 mils to about 5.0 mils, and especially from about 0.5 to about 3.0 mils.

The absorbent article 20 also comprises an absorbent middle 44 located between the upper coating 40 and the lower coating 42. The absorbent middle 44 can be obtained from a single absorbent element or from a composite containing separate absorbent elements. It should be understood, however, that any number of absorbent elements can be used in accordance with this invention. For example, in one embodiment, the absorbent core 44 may include an absorbent element (not shown) located between the top cover 40 and a transmission delay element (not shown). The absorbent element may be made of a material that is capable of rapidly passing, in the z direction, body fluid that enters the upper coating 40. The absorbent element typically has any desired shape and / or size. In one embodiment, the absorbent element has a rectangular shape with a length equal to or less than the total length of the absorbent article 20 and a width less than the width of the absorbent article 20. For example, a length of from about 150 mm to about 300 mm and a width of from about 10 can be used. mm to about 60 mm.

Any and many different materials can be used for the absorbent element to achieve the above functions. The material may be synthetic, cellulosic, or a combination of synthetic and cellulosic materials. For example, aerodynamically produced cellulosic fabrics can be used in an absorbent element. The aerodynamically prepared cellulosic fabric has a base weight of from about 10 grams per square meter (g / m ² ) to about 300 g / m ² , and in some embodiments, from about 100 g / m ² to about 250 g / m ² . In one embodiment, the aerodynamically produced cellulosic fabric has a base weight of about 200 g / m ² . The fabric obtained by the aerodynamic method can be obtained from the fibers of deciduous and / or coniferous wood. The fabric obtained by the aerodynamic method has a finely porous structure and provides excellent absorbency, especially during menstruation.

If desired, an element that impedes passage (not shown) may be located vertically below the absorbent element. The passage retarding element may contain a material that is less hydrophilic than other absorbent elements, and can typically be characterized as practically hydrophobic. For example, the passage retarding element may be a non-woven fibrous web consisting of a relatively hydrophobic material such as polypropylene, polyethylene, polyester or the like, and may also consist of a mixture of such materials. One example of a material suitable for a passage retarding element is a spunbond consisting of polypropylene, multilobal fibers. Other examples of suitable materials for the passage retarding element include a spunbond composed of polypropylene fibers, which may be round, tri-lobal or poly-lobal in cross section, and may be hollow or solid in structure. Typically, the canvas is connected, for example, by thermal bonding, from about 3% to about 30% of the area of the canvas. Other examples of suitable materials that can be used for a passage retarding element are described in US Pat. No. 4,798,603 Mever. et al. and U.S. Patent No. 5,248,309 to Serbiak. et al., which are incorporated herein in their entirety by reference for all purposes. To achieve the effectiveness of the invention, the passage retarding element can also be treated with a selected amount of surfactant to improve the initial wettability.

The passage retarding element can generally be of any size, for example, a length of from about 150 mm to about 300 mm. Typically, the length of the passage retarding element is approximately equal to the length of the absorbent article 20. The element that inhibits passage can also have the width of the absorption element, but is usually wider. For example, the width of the passage retarding element may be from about 50 mm to about 75 mm, and especially about 48 mm. The passage retarding element typically has a basis weight less than that of other absorbent elements. For example, the bulk of the passage retarding element is typically less than about 150 grams per square meter (g / m ² ), and in some embodiments, from about 10 g / m ² to about 100 g / m ² . In one particular embodiment, the passage retarding element is obtained from a spunbond having a basis weight of about 30 g / m ² .

In addition to the above elements, the absorbent core 44 may also include a composite absorbent element (not shown), such as a coformed material. In this case, liquids can be absorbed from the passage retarding element into the composite absorbent element. The composite absorbent element can be obtained separately from the absorbing element and / or the element that impedes the passage, or can be formed simultaneously with it. In one embodiment, for example, a composite absorbent element can be obtained on the element, delaying the passage, or an absorbing element that acts as a carrier during the molding process described above.

Regardless of the particular composition, the absorbent article 20 typically contains adhesive for attachment to underwear. The adhesive can be applied anywhere on the absorbent article 20, for example, to the lower surface of the lower coating 42. In this particular embodiment, the lower coating 42 has a longitudinal central strip of adhesive 54, which is closed prior to use by the release coating film 58, which may be a biodegradable film obtained in accordance with this invention. Each of the lapels 24 may also contain an adhesive 56 located adjacent to the distal edge 34 of the lapel 24. A removable coating film 57, which can also be obtained in accordance with this invention, may cover the adhesive 56 before use. Thus, if the user of the hygienic absorbent article 20 desires to open the adhesive 54 and 56 and attach the absorbent article 20 to the inside of the underwear, he can simply remove the films 57 and 58 and throw them into the waste chute.

Although various configurations of the coating film are described above, it should be understood that other configurations of the coating film are also included in the scope of this invention. Further, the present invention is not limited to coating films, and a biodegradable film can be incorporated into various components of an absorbent article. For example, according to FIG. 3, the bottom cover 42 of the diaper 20 may include a biodegradable film in accordance with this invention. In such embodiments, the film may be used alone to provide a lower coating 42 or laminated to one or more additional materials, such as a non-woven fabric. The biodegradable film in accordance with this invention can also be used in areas other than absorbent products. For example, the film can be used as an individual wrapper, packaging bag or bag for the disposal of many products, such as food products, absorbent products, etc. Various suitable sacks, wrappers or bags for absorbent articles are described, for example, in US Pat. Nos. 6,716,203 to Sorebo. et al. and 6,380,445 Moder. et al., as well as the publication of US patent application No. 2003/0116462 Sorebo. et al., all of which are incorporated herein by reference in their entireties.

The invention may be better raised from the following examples. Test Methods Tear Strength Properties:

The tensile strength of the strip is determined in accordance with ASTM Standard D-5034. Apply a tensile tester with a constant elongation rate. The tensile strength test system is a Sintech 1 / D tensile tester available from Sintech Corp. Cari, North Carolina. The tensile tester is equipped with the TESTWORKS 4.08 V software from MTS Corporation to support testing. A suitable force sensor is selected so that the test value falls within the range of 10-90% of the full scale of the force. Film samples are first cut into bone-shaped pieces with a center width of 3.0 mm before testing. Samples are held between jaws having a front and rear surface measuring 25.4 millimeters × 76 millimeters. The surfaces of the sponges are rubberized and the longer sponge size is perpendicular to the direction of pulling. The clamp pressure is pneumatically maintained at 40 psi. The tensile test is carried out by applying the length of the test portion of the sample to 18.0 millimeters and a tensile sensitivity of 40%. Five samples are tested using test force along the direction of processing, and five samples are tested using test force along the direction across the processing. During testing, the samples are stretched at a crosshead speed of about 127 millimeters per minute before rupture. The coefficient, maximum stress, maximum strain (i.e.,% strain at peak load) and elongation are measured and recorded.

Scanning Electron Microscopy

The plasma etching method is used to obtain samples for SEM structural profiles. Like liquid etching, this method allows topography to be obtained through differential etching rates of materials. Samples placed on an aluminum disk located on ice are separated at room temperature by holding a blade with one cutting edge through the film using a mallet. Parts are cut either in the direction of extrusion (NE) (i.e., the direction of processing, HO), or perpendicular to the direction of extrusion (i.e., in the direction across the processing, PO). The samples obtained are checked for typical and unusual ones, and micrograms illustrating these observations are recorded in digital form.

Preliminary calculations show that a noticeable contrast should occur between Ecoflex and oxidized starch. Parts of the film without additional processing are mounted on an aluminum rack using conductive carbon paint. After drying, the fixed film, while maintaining the surface of the part, is repainted to obtain two conductive paths to the ground. Images of hardened parts are obtained using either a microchannel plate in high vacuum or a solid sensor in partial vacuum to collect backscattered electrons (natural visualization of the backscattered electron spectrum (SCE). Image acquisition conditions are optimized for contrast and resolution, typical images are recorded in digital format and images choose.

Other film samples were stained with osmium tetroxide in a vacuum cap containing 0.5 g of osmium tetroxide for forty-eight hours with a ventilation period of 4 days. The dyed and ventilated films are divided into parts and images are obtained as described above (OO VSOE).

Decorated Secondary Electron Visualization (WWE)

The films separated into parts are decorated with oxygen plasma using an Emitech K1050X cylindrical reactor (from Energy Beam Sciences, Inc., East Granby, Connecticut), which operates at 40 watts with an oxygen flow of 50 mi / min, which is sufficient to produce a white-blue plasma indicating oxygenated plasma. The decorated parts are mounted on an aluminum rack using double-sided gold-plated copper tape, and images are obtained using an Everhart-Thornley sensor operating in the secondary electron imaging mode. Image acquisition conditions are optimized for contrast and resolution, and typical images are recorded digitally.

Materials

Cargill Gum ™ 03460 is a natural (non-oxidized) corn starch. Superfilm® 235D is an oxidized corn starch. Both starches are purchased from Cargill (Minneapolis, MN).

Natural (non-oxidized) wheat starch, Midsol 50, and modified (oxidized) wheat starch, Pregel Adhere 2000, are purchased from MGP Ingredients, Inc. (Atchison, KS).

Oxidized starches are prepared using sodium hypochlorite in a suspension, the pH of which is maintained in the alkaline region.

ECONEER resin, EBP 203 (EBP), purchased from ECONEER Co., Ltd. (Costa Mesa, CA). EBP 203 resin is a mixture of Kondorax and Ecopel biodegradable polymer resins. Kondorax resin is composed of high molecular weight fibers, including, but not limited to, sugarcane, rice straw, oat straw, cane, corn stalks, coconut, grass and so on. Ecopol is a thermoplastic aliphatic complex polyester copolymer that is biodegradable. The decomposition period of ECONEER resin varies from 15 days to at least 12 months. ECONEER resin contains cheap and common renewable components.

Ecoflex® F BX 7011 resin is purchased from BASF (Mount Olive, NJ). Ecoflex® F BX 7011 resin is an aliphatic-aromatic complex copolyester, which consists of three monomers: butanediol, adipic acid and terphthalic acid. EcoLech® F BX 7011 resin is biodegradable and commercially available, but it does not contain renewable components. Ecoflex® F BX 7011 is used to improve the overall functionality of the film.

Polybutylene succinate (PBS), GS-Pla AD92W, purchased from Mitsubishi Chemical Corporation (Tokyo, Japan).

Technological additives, such as glycerin, are purchased from Cognis Corporation (Cincinnati, OH). Mono-di-glyceride surfactant (Excel P-40S) purchased from Kao Corporation (Tokyo, Japan). All of them are used as technological additives.

Obtaining thermoplastic starch Example 1

Pregel Adhere 2000 oxidized wheat starch is converted to thermoplastic oxidized wheat starch using glycerol as a plasticizer and Excel P-40S as a surfactant in the proportions shown in Table 1. Thermo Prism ™ USLAB 16 double-screw extruder (Thermo Electron Corporation, Stone Stone Corporation , England) are used for processing. The extruder has eleven zones: zone 0 is the loading zone where materials from the K-Tron batcher (K-Tron North America, Pitman, NJ) are received and transferred to zones 1, 2, etc. to zone 9. These zones are the compartments of the two worms for mixing, and zone 10 is the head located at the end of the extruder. The temperature settings for example 1 are 90, 100, 115, 125, 130, 130, 130, 125 and 120 ° C for zones 1-9. The temperature of the head is 115 ° C. The rotational speed of the worm is 150 rpm. After mixing with Excel P-40S, oxidized wheat starch is fed at a rate of 1.5 ft / h. Glycerin is pumped into zone 1 using a gear pump (Bodine Electric Company, Grand Island, NY). Under these conditions, the torque is 82 to 86%, and the pressure is 10-11 bar. All these processing conditions are summarized in example 1 in table 1. When forming the thread, it is cooled on a conveyor (Bondie Electric Company, Chicago, IL). A granulator (Emerson Industrial Controls, Grand Island, NY) is used to cut the yarn to produce granules of thermoplastic oxidized wheat starch, which are then collected and sealed in a plastic bag.

Example 2

Natural wheat starch, Midsol 50, is treated in the same manner using the same equipment as shown in Example 1. The processing parameters are shown in table 1.

Example 3

Oxidized corn starch, Superfilm® 235D, is converted to thermoplastic oxidized starch using the same equipment as shown in Example 1. The processing parameters are shown in Table 1.

Example 4

Natural corn starch is converted into thermoplastic oxidized starch using the same equipment as shown in Example 2. The processing parameters are shown in table 1.

Film production

A control film of Ecoflex® F BX 7011 resin was cast for Example 5 using a Thermo Prism ™ USLAB 16 twin-screw extruder (Thermo Electron Corporation, Stone, England), after attaching a 4 inch film head. The temperature profile for film casting is shown in Table 2, including other processing conditions such as melting pressure, torque, and worm rotation speed. The thickness of the control film is about 1.5 and 2 mil, respectively. Examples 6-19 are film mixtures containing various mixtures of biodegradable resins and thermoplastic starch, the compositions of which and processing conditions are shown in 2 and 3.

Examples 5-10 work well. Thin films were successfully prepared from mixtures of thermoplastic oxidized starch and copolyester containing 20 wt.%, 30 wt.%, 40 wt.% And 45 wt.% Thermoplastic oxidized starch. Unexpectedly, a thin film is also successfully obtained from mixtures containing most of the thermoplastic oxidized starch (Example 10) 60% by mass.

For example 11, films of more than 4-5 mil or more are suitable for melt casting, although the mechanical integrity of the film of example 11 is not as good as for the films obtained from examples 6-10. Therefore, for the film of example 11, a tensile test is not carried out.

Examples 12 and 13 use a mixture of natural corn thermoplastic starch and Ecoflex® F BX 7011 film casting resin. If the proportion of natural corn thermoplastic starch is more than 50 or 60% in the mixture, a flexible film cannot be obtained. Compared to example 10, examples 12 and 13 demonstrate that the oxidation of wheat starch provides compositions for producing films that contain most of the thermoplastic oxidized starch in mixtures.

For examples 14 and 15, it is very difficult to obtain a film if the composition contains thermoplastic natural wheat starch in an amount of more than 35% of the mass.

Examples 16-17 use oxidized corn starch from Cargill, Inc. for film casting.

A film can only be obtained if Ecoflex® F BX 7011 resin is the main component. If the oxidized starch is more than 50%, thin and flexible films cannot be obtained.

Example 18 is a mixture of 55% ECONEER EBP 203 and 45% thermoplastic oxidized starch from Example 1. The resulting film has a thickness of more than 3 mil.

Example 19 is a mixture of 60% PBS and 40% thermoplastic oxidized starch from Example 1. Films are obtained by melt casting, and they are much better than films from Example 18.

The mechanical properties of the film

Table 4 lists all the properties of the tensile strength of the film from examples 5-19, with the exception of example 11, which cannot be tested. The film coefficient and elongation data for examples 5-10 in the form of graphs are shown in Figures 4 and 5, respectively. The “error” column is the standard deviation. The film coefficient is stable without deterioration in film stiffness with an increase in the amount of thermoplastic oxidized starch, as shown in FIG. 4, which indicates complete mixing of the mixtures. On the other hand, film elongation is generally a relatively high elongation for all films with increasing amounts of thermoplastic oxidized starch. Films containing thermoplastic oxidized starch have a better overall elongation, with the exception of 40/60, which is not very different from a film containing only Ecoflex® F BX 7011 resin.

Examples 12 and 13 use natural corn thermoplastic starch, and the film coefficient is higher than the coefficient of the films of examples 5-10, regardless of the amount of EcoPech® F BX 7011 resin in the mixture, which shows less flexibility of the films of examples 12 and 13. The maximum voltage and deformation is also reduced, especially for the film of example 13.

In examples 14 and 15, natural wheat thermoplastic starch is used, while the film coefficient is approximately equal to the coefficients of examples 5-10, but the amount of starch in the mixtures is relatively low.

Examples 16 and 17 use oxidized corn starch. Therefore, they should be comparable with examples 9 and 8, respectively, where the ratios of Ecoflex® F BX 7011 resins and TPOS are the same. Oxidized corn starch is not as effective as oxidized wheat starch in film coefficient and technological properties of a thin film.

Example 18 is a mixture of ECONEER EBP 203 and oxidized wheat starch (55/45), which gives a thick film. Durable tear film is also lower.

Example 19 is a mixture of PBS and oxidized wheat starch (60/40). The film tensile strengths are better than for Example 18, but worse than for Ecoflex® F BX 7011 resin and oxidized wheat starch mixtures used in Examples 6-10.

6 is a micrograph of an SEM film from Example 6 (20% thermoplastic oxidized starch), where Ecoflex® F BX 7011 resin forms a continuous phase and the thermoplastic oxidized starch is uniformly distributed over the film.

Fig. 7a shows an image of backscattered electrons (BCEE) of the film of Example 8 (40% thermoplastic oxidized starch), where Ecoflex® F BX 7011 resin serves as a continuous (matrix) phase and starch serves as a dispersed phase. The dark area means Ecoflex® F BX 7011 resin and the bright areas indicate thermoplastic oxidized starch, given that this SEM is obtained using the HSE method with osmium staining.

Fig.7b presents the image of the secondary electrons of the film from example 8. The film is etched for 4 minutes with plasma. During plasma treatment with Ecoflex® F BX 7011, the polymer is pickled at a higher rate than the thermoplastic oxidized starch phase. The presence of etched voids confirms that the continuous phase is the Ecoflex® F BX 7011 resin phase and the dispersed phase is the thermoplastic oxidized starch phase. In this image, in the direction across the processing (PO), the size of the dispersed phase varies greatly, from sub-micron to several microns. The substantially circular cross-section of some dispersed structures of thermoplastic oxidized starch in Fig. 7b suggests that some of the dispersed phase of thermoplastic oxidized starch may have a substantially circular, fiber-like structure, although there is also a portion of thermoplastic oxidized starch that looks like strip-like structures in cross section.

On figa presents an image of backscattered electrons (VCEE) of the film from example 10 (60% thermoplastic oxidized starch, 40% Ecoflex® F BX 7011 resin). Most of the material in the mixture is thermoplastic oxidized starch in a proportion of 60%. The phases of thermoplastic oxidized starch are interconnected as highly elongated dispersed leaf-shaped structures. The film has a microstructural characteristic that mimics a micro-layered film laminate in which thin layers of a copolyester of submicron thickness are sandwiched between micro-layers of thermoplastic oxidized starch with a thickness from submicron to several microns. It is believed that this type of unique microstructure gives the film good mechanical properties since Ecoflex® F BX 7011 resin is a continuous matrix phase, as shown in Fig. 8a, despite the predominance of thermoplastic oxidized starch in the mixture. This SEM is also prepared using the HSE method with osmium staining.

On fig.8b presents the image of the secondary electrons of the cross section of the film from example 10. The film is etched for 4 minutes by plasma. During plasma treatment with Ecoflex® F BX 7011, the polymer is pickled at a higher rate than the thermoplastic oxidized starch phase. The presence of etched voids confirms that the continuous phase is the Ecoflex® F BX 7011 resin phase and the dispersed phase is the thermoplastic oxidized starch phase. Obviously, the dispersed phase makes up the bulk of the cross section. The elongated cross-sections of the many dispersed structures of thermoplastic oxidized starch in Fig. 8b suggest that some of the dispersed phase of thermoplastic oxidized starch may have a strip-like structure, although there is also a portion of thermoplastic oxidized starch that looks like strip-like structures in cross section.

Fig. 8c shows an image of the secondary electrons of the film of Example 10 in the processing direction. The film is etched for 4 minutes with plasma. During plasma treatment with Ecoflex® F BX 7011, the polymer is pickled at a higher rate than the thermoplastic oxidized starch phase. The presence of etched voids confirms that the continuous phase is the Ecoflex® F BX 7011 resin phase and the dispersed phase is the thermoplastic oxidized starch phase. Obviously, the dispersed phase makes up the bulk of the cross section. The elongated cross-sections of the many dispersed structures of thermoplastic oxidized starch in Fig. 8c suggest that some of the dispersed phase of thermoplastic oxidized starch may have a sheet structure, where some sheet structures have a length of more than 5 microns and even more than 10 microns. Between the structures of the thermoplastic oxidized starch, Ecoflex® F BX 7011 resin is substantially dispersed, providing overall plasticity to the film.

The molecular weight distribution of starch is shown in Table 5. The polydispersity coefficient (Mw / Mn) for oxidized wheat or corn starch is higher than for natural wheat or corn starch. A higher polydispersity coefficient shows that the molecular weight distribution for oxidized starch is much wider than for natural starch. Without pretending to the theory, it is believed that increasing the polydispersity coefficient improves the starch's ability to form a thin and flexible film.

Although the invention has been described in detail with reference to specific examples, one skilled in the art should understand, in light of the foregoing, that changes, variations, and equivalents to these options are possible. Therefore, the scope of this invention is defined by the claims and any equivalents thereof.

Table 1 Thermoplastic Starch Processing Conditions Mixture Mixture composition Extruder Extruder temperature profile (° C) Sample No. Feed rate Starch Excel P-408 Glycerol Speed P (melt) Cr. moment (ft / hour) % % % (rpm) T ₁ T ₂ T ₃ T ₄ T ₅ T ₆ T ₇ T ₈ T ₉ T _heads bar (%) Example 1 1,5 78,4 1,6 twenty 150 90 one hundred 115 125 130 130 130 125 120 115 10-11 82-86 Example 2 1.8 73.5 1,5 25 150 90 one hundred 110 125 130 130 120 125 120 115 35 = 37 55-58 Example 3 1.9 74.5 1,5 24 150 95 110 125 135 150 150 150 135 125 115 30-35 65-70 Example 4 2,3 76,4 1,6 22 150 90 one hundred 115 120 130 130 130 120 115 110 9-10 55-60

table 2 The processing conditions of the mixture for a film of wheat thermoplastic oxidized starch and complex copolyester Mixture Mixture composition Extruder Extruder temperature profile (° C) Sample No. Feed rate Pregel Adhere 2000 TPS Ecoflex Speed P (ras-melt) Cr. moment (ft / hour) % % (rpm) T ₁ T ₂ T ₃ T ₄ T ₅ T ₆ T ₇ T ₈ T ₉ T _heads bar (%) Example 5 0 one hundred 150 120 130 140 155 155 160 155 155 155 150 14-15 70-75 Example 6 twenty 80 150 120 130 140 145 150 150 150 150 145 140 6-7 55-58 Example 7 thirty 70 150 120 130 140 145 150 150 150 150 145 140 7-8 58-63 Example 8 40 60 150 120 130 140 145 150 150 150 150 145 140 9-10 60-63 Example 9 2.5 45 55 150 120 130 140 145 150 150 150 150 145 140 6-7 50-52 Example 10 60 40 150 120 130 140 145 150 150 150 150 145 140 10-11 50-55 Example 11 70 thirty 150 120 130 140 145 150 150 150 150 145 140 9-10 53-56

Table 3 Processing conditions for a starch-based thermoplastic copolyester film mixture Mixture Mixture composition Extruder Extruder temperature profile (° C) Sample No. Feed rate Tps Ecoflex Speed P (melt) Cr. moment (ft / hour) % (rpm) T ₁ T ₂ T ₃ T ₄ T ₅ T ₆ T ₇ T ₈ T ₉ T _heads bar (%) Example 12 2.5 30% of example 4 70 150 120 130 140 150 160 160 160 155 150 145 9-10 60-64 Example 13 45% of example 4 55 150 120 130 140 150 160 160 160 155 150 145 10-11 65-70 Example 14 2.5 20% of example 2 80 150 120 130 140 150 160 160 160 155 150 145 7-8 55-58 Example 15 30% of example 2 70 150 120 130 140 145 150 150 150 150 145 140 8-9 53-57 Example 16 2.5 45% of example 3 55 150 120 130 140 145 150 150 150 150 145 135 6-7 48-50 Example 17 40% of example 3 60 150 120 130 140 145 150 160 160 155 150 145 7-8 55-58 Example 18 2.5 45% of example 1 55% EBP 150 120 130 140 145 150 150 150 150 145 140 9-10 50-54 Example 19 2.5 40% of example 1 60% PBS 150 120 130 140 150 160 160 160 155 150 145 11-12 53-55

Table 4
Mechanical properties of films based on a mixture of thermoplastic oxidized starch - an aliphatic aromatic complex copolyester Sample No. Sample Description Composition The mechanical properties of the film Film thickness Coefficient (MPa) Maximum voltage (MPa) Strain (%) BUT (mil) PNO (mil) BUT PNO BUT PNO BUT PNO Example 5 Ecoflex F BX 7011 100/0 1.3 1.3 74.6 83.5 42.1 35.3 442.7 744.2 Example 6 Ecoflex / example 1 80/20 1.3 1,2 93,4 82,2 34,4 30,2 657.3 827.4 Example 7 Ecoflex / example 1 70/30 1,1 1,2 70.1 65.0 30.1 21.7 645.2 758.4 Example 8 Ecoflex / example 1 60/40 1.4 1,2 61.9 74.3 29.8 17.4 669.2 646.8 Example 9 Ecoflex / example 1 55/45 1.4 1.4 49.0 59.3 24.0 13.9 656.3 644.4 Example 10 Ecoflex / example 1 40/60 1.4 1.7 73.9 77.7 17.3 8.1 547.5 444.5 Example 12 Ecoflex / example 4 70/30 1.8 1.7 106.3 112.3 25.7 15.3 690.8 597.9 Example 13 55/45 1.4 1.3 255.9 255.9 16,0 8.0 435.4 36.8 Example 14 Ecoflex / example 2 80/20 3.0 2.6 76.8 79.0 24.0 15.1 782.5 556.8 Example 15 70/30 3.0 2.6 70.7 107,2 21.9 11.6 695.1 433.7 Example 16 Ecoflex / example 3 55/45 1,6 1,2 72.1 103,2 25,4 11.3 548.9 385.0 Example 17 60/40 1,6 1,5 118.3 96.1 29.2 16,4 601.8 600.7 Example 18 EUR / example 1 55/45 3.3 3.2 144.6 93.1 9.6 4.7 164.4 10,4 Example 19 PBS / example 1 60/40 1,5 1,5 110.1 129.6 22.8 12.6 375.3 394.2

Table 5 Starch molecular weight distribution for starch sample Starch sample Mn Mw Mz Mw / mn Midsol 50 183,500 7,731,000 21,770,000 42 Pregel adhere 2000 28,300 3,224,000 10,670,000 114 Cargill Cum ™ 03460 182,600 3,231,000 12,41,000 eighteen Super-film 235®D 35,500 2,455,000 9,165,000 69

Claims (20)

1. Biodegradable film, characterized in that it contains:
from about 1 wt.% to about 49 wt.% by weight of the film of the matrix phase containing at least one biodegradable polyester; and
from about 46 wt.% to about 75 wt.% by weight of a dispersed phase film containing at least one oxidized corn or oxidized wheat starch and at least one plasticizer;
where the dispersed phase is dispersed in the matrix phase, and also where the wt.% of the matrix phase of the film mass is less than the wt.% of the dispersed phase of the film mass. 2. The biodegradable film according to claim 1, characterized in that the biodegradable polyester is an aliphatic polyester, an aliphatic-aromatic polyester, or a combination thereof. 3. The biodegradable film according to claim 1, wherein the biodegradable polyester is from about 20% to about 43% by weight of the film. 4. The biodegradable film according to claim 1, wherein the oxidized starch is from about 45% to about 65% by weight of the film. 5. The biodegradable film according to claim 1, where the plasticizer is from about 5 wt.% To about 30 wt.% By weight of the film. 6. The biodegradable film according to claim 1, wherein the oxidized starch is modified oxidized corn or wheat starch. 7. The biodegradable film of claim 6, wherein the modified oxidized starch is starch ester, starch ether, hydrolyzed starch, or a combination thereof. 8. The biodegradable film according to claim 1, wherein the plasticizer is polyhydric alcohol. 9. The biodegradable film of claim 1, wherein the film has a thickness of about 50 microns or less. 10. The biodegradable film according to claim 1, where the film has a coefficient of elasticity in the dry state from about 50 to about 100 MPa in the processing direction. 11. The biodegradable film according to claim 1, where the film has an elongation at break in the processing direction of more than 500%. 12. A coating film containing a biodegradable film according to claim 1 and a release agent deposited on its surface. 13. An absorbent article comprising a biodegradable film according to claim 1, wherein the absorbent article has a body-adjacent portion that includes a liquid-permeable topcoat, a generally liquid-impermeable topcoat, and an absorbent core located between the bottomcoat and the topcoat. 14. The absorbent article of claim 13, wherein the bottom coating comprises a biodegradable film. 15. The absorbent article of claim 13, further comprising a coating film that defines a first surface and an opposite second surface, where the first surface is adjacent to an adhesive applied to the absorbent article, where the coating film includes a biodegradable film. 16. A bag, wrapper or bag containing a biodegradable film according to claim 1. 17. An absorbent article having a body-adjacent portion that includes a liquid-permeable topcoat, a generally liquid-impervious undercoat, and an absorbent middle located between the bottom and the topcoat, where the absorbent article also includes a cover film that defines the first surface and the opposite second surface, where the first surface is adjacent to the adhesive deposited on the absorbent article, where the coating film, the lower coating, or both contain from about 1 wt.% to about 49 wt.% of the matrix phase containing at least one biodegradable polyester, and from about 46 wt.% to about 75 wt.% of the dispersed phase containing at least one oxidized corn or oxidized wheat starch and at least one plasticizer, where the dispersed phase is dispersed in the matrix phase and where the mass% of the matrix phase is less than the mass% of the dispersed phase. 18. The absorbent product according to claim 17, where the oxidized starch is from about 45 wt.% To about 65 wt.% By weight of the film. 19. The absorbent product according to claim 17, where the plasticizer is from about 5 wt.% To about 30 wt.% By weight of the film. 20. Biodegradable film, characterized in that it contains:
from about 1 wt.% to about 49 wt.% by weight of the film of at least one biodegradable polyester; and
from about 46 wt.% to about 75 wt.% by weight of a film of thermoplastic oxidized starch containing at least one oxidized corn or oxidized wheat starch and at least one plasticizer;
where wt.% biodegradable polyester by weight of the film is less than wt.% thermoplastic oxidized starch by weight of the film.

Images