WO2011024021A1

WO2011024021A1 - Sizing composition containing a biodegradable polymer

Info

Publication number: WO2011024021A1
Application number: PCT/IB2009/007043
Authority: WO
Inventors: Patrick Moireau; Adina M. Cretu
Original assignee: Ovc Intellectual Capital, Llc
Priority date: 2009-08-31
Filing date: 2009-08-31
Publication date: 2011-03-03

Abstract

A biodegradable polymer emulsion and a sizing composition for reinforcement fibers that utilizes the biodegradable polymer emulsion as the film forming component is provided. The biodegradable polymer emulsion is typically water based and contains at least one biodegradable polymer, a surfactant, and a plasticizer. The biodegradable polymer utilized in the polymer emulsion is natural in origin and is derived from renewable resources. In exemplary embodiments, the biodegradable polymer is selected from polyhydroxyalcanoates and polylactides. The aqueous biodegradable polymer emulsions are free of organic solvents, are stable over time, have a dry matter content of at least 30%, a low viscosity, and an average particle size between 10 and 150 microns. The size composition includes a biodegradable polymer emulsion, at least one silane coupling agent, one or more lubricants, a plasticizer/surfactant dispersing system, and water. The size composition may be used to size a biodegradable reinforcing fiber to form a biodegradable product.

Description

TITLE OF THE INVENTION

SIZING COMPOSITION CONTAINING A BIODEGRADABLE POLYMER

TECHNICAL FIELD AND INDUSTRIAL APPLICABILITY OF THE INVENTION

[0001] The present invention relates generally to a sizing composition for a reinforcing fiber material, and more particularly, to a sizing composition that utilizes a biodegradable polymer emulsion as a film forming agent.

BACKGROUND OF THE INVENTION

[0002] Environmental awareness is increasing and more concern regarding the environment and biodegradability of products can be seen around the globe. Thermoplastic resins are currently used to form plastic products, which are used by consumers and then disposed of by either by incineration or dumping the used plastic product in a landfill. The conventional manufacture of aqueous polymer dispersions is based mainly on processes of direct emulsion polymerization of synthetic monomers of styrene, ethylene, propylene, vinyl alcohol, and acrylamide monomers. These synthetic polymer emulsions are used, for example, to coat cardboard or paper to give them water-resistant properties. The application of these polymer dispersions as a thin coat on the inner face of paper packaging, such as for milk or fruit juices, has led the production of packaging that is difficult to recycle and to biodegrade in conventional landfills.

[0003] The polymer emulsions may also be used as part of a sizing composition used to treat glass fibers. The sizing composition, or chemical treatment, containing a film forming polymeric component (e.g., polymer emulsion), a coupling agent, and a lubricant are typically applied to the fibers after they are drawn from a bushing. The sizing composition is added to glass fibers to reduce interfilament abrasion and to make the glass fibers compatible with the polymeric matrices they are intended to reinforce. The sizing composition also ensures the integrity of the strands of glass fibers (e.g., the interconnection of the glass filaments that form the strand), reduce electrostatic charges, and improve mechanical properties of the composites formed therefrom.

[0004] It is believed that the plastic materials forming the plastic product have an adverse influence on the environment and biological systems at least partially due to their non-degradability. For instance, non-degradable polymers affect ecological systems by their long term presence, they potentially eliminate ecological systems by increasing and expanding landfill sites around the globe, and their incineration may contribute to global warming. Thus, both consumers and governmental authorities have become more aware of the impact that the disposal of different plastic, synthetic, and oil based products have on the environment, and are looking to alternatives to these non-degradable materials.

[0005] New solutions are being discovered or developed to deal with the

extraordinary amount of plastics used both in the United States and abroad. In this regard, the production of bio-based plastics which auto-degrade in an ecological manner have been developed. The biodegradability of plastic materials depends on their structure and on the composition of the final products as well as the raw materials used for their production.

Biodegradable polymers may have a natural or a synthetic origin. Resins of natural origin may be obtained from renewable resources (e.g., starch), they may be naturally occurring, or they may be synthesized. Synthetic resins issued from non-renewable resources are generally oil based.

[0006] The interest for polymers derived from renewable resources has been increasing lately, especially with regard to biodegradable polymers, where the concept of "life cycle analysis" may be applied. The "life cycle analysis" considers all of the initial concerns (e.g., needs, raw materials, energy sources, etc.) and all the final concerns (e.g., impact during production, use, waste, etc.). The use of biodegradable polymers derived from renewable resources is promising; however, the current cost of these polymers does not permit them to be competitive with conventional synthetic, oil based polymers.

[0007] In an attempt to make biodegradable polymers a viable alternative to conventional non-degradable resins, intensive research and development on aqueous polymer dispersions prepared from biodegradable polymers is being conducted. Initial techniques have used biodegradable polymers in an unmodified form (e.g., in a melt form), which requires the use of high temperatures. However, the films prepared from the polymers are undesirably thick. Extrusion/drawing techniques may be used to generate thinner films, but these techniques are expensive and both material- and energy-intensive. Some other attempts to obtain viable biodegradable products are set forth below.

[0008] hi JP Patent Application No. 4 334448, which discusses the manufacture of water-resistant films, the approach adopted was either to spray the surface of the paper with a lactic acid polymer dissolved in a volatile organic solvent or to immerse the paper in an organic solvent that contains polylactic acid. Although the choice of a lactic acid polymer instead of a synthetic resin contributes towards the resolution of the problem of

biodegradability of the polymers and consequently the packaging, it is not entirely

satisfactory. In particular, the use of volatile organic compounds (VOCs) as solvents to deposit the polylactic acid or its derivatives on the surface of a substrate requires complex and/or delicate handling due to the mandatory safety precautions imposed as a result of the toxicity of the volatile organic solvent (e.g., flammable solvents, risk of explosion, inhalation by the worker, environmental pollution, etc.).

[0009] JP Patent Application No. 10-101 911 describes the production of a resistant biodegradable film that begins with an emulsion of a dispersion of fine emulsified globules of polylactic acid that contains an anionic emulsifier. Unfortunately, this process retains the drawback of requiring the use of a volatile organic solvent such as methylene chloride, chloroform, dioxane, or acetonitrile to disperse the lactic acid polymer as an emulsion.

[0010] JP Patent Application No. 2001-11294 teaches biodegradable aqueous dispersions that include, along with a biodegradable resin of an aliphatic polyester, a mixture of a cationic macromolecular compound with a molecular weight of at least 300,000 or an anionic macromolecular compound with a molecular weight of at least 1,000,000 and polyvinyl alcohol (PVA). One drawback with this dispersion is the use of the nonbiodegradable mixture of cationic or anionic macromolecular compounds/PVA.

Additionally, other agents, such as thickeners, flow index modifiers, and the like, may be added to the emulsion, which increases the overall cost of the aqueous dispersion. In addition, it is still necessary to use a large excess of a volatile organic solvent, which requires the use of a subsequent step of stripping off a large proportion of this organic solvent under a high vacuum. Moreover, this biodegradable emulsion is not entirely satisfactory, particularly due to the number of manipulations that have to be performed to achieve the mixture and the fact that a very precise equilibrium of the components needs to be obtained in order to acquire an industrially advantageous product.

[0011] JP Patent Application No. 2001-303 478 describes a process for manufacturing sheets of paper coated with a layer of biodegradable plastic. The biodegradable plastic is utilized to give the paper mechanical strength, printability, water-resistance properties, and stability. The biodegradable plastic emulsion is applied to a sheet of paper to deposit thereon a layer of biodegradable plastic. The biodegradable plastic emulsions are prepared by dissolving a lactic acid polymer in a volatile organic compound (Le., ethyl acetate) and subsequently adding an emulsifier, such as fatty acid salts, carboxylate ethers, alkenyl succinates, or alkyl sulphates. This biodegradable solution is both labor-intensive and complex, and requires the addition of numerous ingredients, both into the organic phase and into the dispersing aqueous phase. Further, the solution requires the presence of volatile organic solvents.

[0012] U.S. Patent Application Serial No. 2005/0058712 describes a process for obtaining an aqueous dispersion of a biodegradable polymer that utilizes a viscosity reducing agent (e.g., a plasticizer). However, the emulsion fabrication processes requires three separate steps. Additionally, the manipulation of the biodegradable polymer is in the molten state, i.e., at a temperature around 160 °C.

[0013] All the polymer emulsions discussed above have significant drawbacks. For instance, all the polymer dispersions require the use of a volatile organic solvent to dissolve the biodegradable polymer, irrespective of the preparation process used. Accordingly, problems of toxicity, cost, complex steps, the obligation to install leak-prevention devices, anti-deflagration devices, and/or devices to recover the volatile organic solvents, and the inevitable environmental impact of the organic solvent remain. In addition, the use of volatile organic solvents leads to aqueous dispersions having a low dry matter (DM) content.

Accordingly, it is necessary to add various stabilizers, emulsifiers, and/or thickeners to the polymer dispersion. Additionally, the synthetic nature of the polymers is detrimental to the biodegradability of the aqueous dispersion obtained. Further, the biodegradable aqueous dispersions discussed above all have a limited stability (i.e., they are stable for more than 1 to 2 months at 20 °C or at 40 °C). As a result, they cannot be used for applications in which the required stability times are longer than 1 or 2 months.

[0014] Accordingly, there remains a need in the art for a cost-effective, stable, environmentally friendly biodegradable polymer emulsion that can be incorporated into a sizing composition for a biodegradable fiber to form a biodegradable product.

SUMMARY OF THE INVENTION

[0015] It is an object of the present invention to provide an aqueous biodegradable polymer emulsion that contains a biodegradable polymer, a surfactant, a plasticizer, and water. The biodegradable polymer is desirably selected from polyhydroxyalcanoates (PHAs) and polylactides (PLAs). The surfactant decreases the interfacial surface tension and facilitates the formation of the emulsion. The plasticizer aids in reducing intra-molecular cohesion and reduces both the viscosity and melting temperature of the biodegradable polymer. The aqueous biodegradable polymer emulsions are stable over time, are free or substantially free of volatile organic compounds, and have a dry matter content of at least 30%. In addition, the polymer emulsions have an average particle size from about 10 microns to about 150 microns evenly or substantially evenly dispersed throughout the emulsion.

[0016] It is another object of the present invention to provide a method of making an aqueous polymer dispersion that contains a biodegradable polymer. The emulsion may be made by a one step process in which the biodegradable polymer, surfactants, plasticizers, and water are mixed in a high pressure reactor at a temperature beyond the melting point of the polymer with high stirring. A rapid cool down of the reactor is conducted to avoid recrystallization of the polymer. The aqueous biodegradable polymer dispersion thus formed is stable over time, has a dry matter content of at least 30%, and a viscosity at 25 ⁰C between about 30 mPas and about 3,000 mPas as measured by a Brookfield LVF viscometer. In addition, the polymer dispersions have an average particle size from about 10 microns to about 150 microns.

[0017] It is also an object of the present invention to provide a sizing formulation that utilizes a biodegradable polymer emulsion as the film former, at least one silane coupling agent, one or more lubricant, and a plasticizer/surfactant dispersing system. The aqueous biodegradable polymer emulsion contains a biodegradable polymer, a surfactant, a plasticizer, and water. Additional components of the size composition are chosen among biodegradable products or products that contain low or no toxicity, and may include wetting agents, pH adjusters, antioxidants, antifoaming agents, processing aids, and/or antistatic agents. When the size composition is used with a biodegradable polymer and a biodegradable reinforcement fiber, a composite product is formed that, under certain conditions, is completely

biodegradable.

[0018] It is yet another object of the present invention to provide a glass fiber sized with the sizing composition described above. The sized fiber may be used to treat any type of glass, such as C-type glass, E-type glass, R-type glass, S-glass and boron free glass such as

Owens Coming's Advantex^® glass fibers. In some embodiments, the reinforcing fiber is C3- type glass or E-type glass. The fibers are used as reinforcement for thermoplastic or thermosetting polymers, particularly biodegradable thermoplastic polymers.

[0019] It is a further object of the present invention to provide a composite product.

Reinforcing fibers sized with a sizing composition that utilizes a biodegradable polymer emulsion as the film forming polymer may be used in an extrusion or injection molding process to form the composite product. The polymer utilized in the molding process may be a biodegradable polymer. When a soluble glass fiber is utilized in conjunction with the biodegradable polymer, the composite product may be completely biodegradable.

[0020] It is an advantage of the present invention that polyhydroxyalcanoates (PHAs) and polylactides (PLAs) are placed into a water-based emulsion.

[0021] It is also an advantage of the present invention that the inventive sizing composition, when used with a biodegradable polymer and biodegradable reinforcement fiber, produces a composite product that is completely biodegradable.

[0022] It is another advantage of the present invention that absence of organic solvents in the size composition eliminates the emission of volatile organic compounds

(VOCs), into the air.

[0023] It is a further advantage of the present invention that the polymers are of natural origin. [0024] It is another advantage of the present invention that the utilization of water to form the biodegradable emulsion reduces cost because water is a readily available and inexpensive resource.

[0025] It is a feature of the present invention that the biodegradable polymer emulsion replaces synthetic, oil-based polymer conventionally used as film forming agents.

[0026] It is another feature of the present invention that PLA and PHB water-based emulsions are utilized in a biodegradable sizing composition.

[0027] It is a further feature of the present invention that the biodegradable polymer utilized in the polymer emulsion is natural in origin and is derived from renewable resources.

[0028] It is also a feature of the present invention that the water-based biodegradable emulsions are stable emulsions and have a high dry matter content.

[0029] It is yet another feature of the present invention that the biodegradable polymer dispersions have an average particle size from about 10 microns to about 150 microns substantially evenly dispersed throughout the emulsion.

[0030] It is another feature of the present invention that the aqueous biodegradable polymer dispersions are stable over time.

[0031] The foregoing and other objects, features, and advantages of the invention will appear more fully hereinafter from a consideration of the detailed description that follows.

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The advantages of this invention will be apparent upon consideration of the following detailed disclosure of the invention, especially when taken in conjunction with the accompanying drawings wherein:

[0033] FIG. 1 is a graphical illustration of process conditions for a reactor for PHB emulsification; and

[0034] FIG. 2 is a graphical illustration of process conditions for a reactor for PLA emulsification.

DETAILED DESCRD7TION AND

PREFERRED EMBODIMENTS OF THE INVENTION [0035] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, certain methods and materials are described herein. AU references cited herein, including published or corresponding U.S. or foreign patent applications, issued U.S. or foreign patents, and any other references, are each incorporated by reference in their entireties, including all data, tables, figures, and text presented in the cited references.

[0036] The terms "film former" and "film forming agent" may be used

interchangeably within this application. Additionally, the terms "size", "sizing composition", and "size composition" may be interchangeably used herein. Further, the terms "emulsion" and "dispersion" may be interchangeably used within this application.

[0037] The present invention relates to a biodegradable polymer emulsion and a sizing composition for reinforcement fibers that utilizes the biodegradable polymer emulsion as the film forming component. The sizing composition includes a biodegradable polymer emulsion, at least one silane coupling agent, one or more lubricants, a plasticizer/surfactant dispersing system, and water. The biodegradable polymers are polymers of natural origin. Additional components of the size composition are chosen among biodegradable products and/or products that contain low or no toxicity. The biodegradable polymer emulsion is a water-based emulsion. The absence of organic solvents in the size composition reduces or eliminates the emission of volatile organic compounds (VOCs).

[0038] The sizing composition includes a film forming agent that functions to protect the reinforcing fibers from damage during processing and imparts compatibility of the fibers with the matrix resin. Film formers create improved adhesion between the reinforcing fibers, which results in improved strand integrity. In the present invention, the film former is a biodegradable polymer emulsion or a combination of separate biodegradable polymer emulsions. As used herein, the term "biodegradable polymer" is meant to denote that the polymer is degraded by the action of microorganisms, particularly soil microorganisms, and/or by the action of natural agents (e.g., water). The biodegradable polymer emulsion replaces synthetic, oil-based polymers that are conventionally used as film formers in sizing formulations. The biodegradable polymer utilized in the polymer emulsion is natural in origin and is derived from renewable resources. In exemplary embodiments, the

biodegradable polymer is a biodegradable polyester.

[0039] Non-limiting examples of biodegradable polymers for use in the biodegradable polymer emulsion include polylactides (PLAs), poly(glycolic acid), polycaprolactone, polybutylene succinate, and polyhydroxyalcanoates (PHAs) such as, but not limited to, polyhydroxybutirate or polyhydroxybutirate - polyhydroxyvalerate copolymers. Specific examples of biodegradable polymers include PHB Biocycle 1000 (a polyhydroxybutyrate commercially available from PHB Industrial SA, Brazil), PHB Biocycle 2000 (a

polyhydroxybutyrate-co-hydroxyvalerate commercially available from PHB Industrial SA, Brazil); PLA 7000D (a polylactic acid with a molecular weight of 112,000 g/mole

commercially available from NatureWorks, LLC, USA); and PLA 305 ID (a polylactic acid with a molecular weight of 84,000 g/mole commercially available from NatureWorks, LLC, USA). As used herein, the term "molecular weight" is meant to denote a weight average molecular weight as determined by standard method gas permeation (GPC) chromatography in tetrahydrofuran (THF).

[0040] Desirably, the biodegradable polymer is selected from polyhydroxyalcanoates

(PHAs) and polylactides (PLAs). The total polymer content in the biodegradable polymer emulsion is from about 15% to about 60% by weight of the aqueous dispersion, and in some embodiments from about 30% to about 50% by weight.

[0041] Polyhydroxyalcanoates (PHAs) are semi-crystalline aliphatic polyesters that naturally occur via bacterial synthesis starting from a hydrocarbonate source and

accumulating in the bacteria during its growth. Thus, the PHAs have a natural and biological origin and present an inherent biodegradability. The production of PHAs may be from renewable resources derived, for example, from agriculture or waste. Depending on the nutrients given to the bacteria, the chemical structure may vary in that homopolymers or copolymers having different functional groups may be produced. Non-limiting examples of PHAs that may be used in the biodegradable polymer film forming emulsion include PHA is poly-3-hydroxybutyrate (PHB), poly-hydroxyvalerate (PHV), and the copolymer

poly(hydroxybutirate-co-hydroxyvalerate) (PHBV). The PHA concentration in the biodegradable polymer emulsion may be from about 10% to about 40% of the total weight of the emulsion, in some embodiments from about 25% to about 40% by weight of the emulsion, and in some embodiments between 18% and 25% by weight.

[0042] Polylactides are linear aliphatic polyesters obtained by ring opening polymerization of dilactide (e.g., a lactic acid dimer or 2-hydroxypropionic acid). Lactic acid may be obtained by starch fermentation, such as, for example, from corn milling. Properties of PLAs such as the melting point, mechanical properties, and crystallinity depend on the polymer structure, the proportion between the stereo isomers L-, D-, and meso-lactide, and the molecular weight. The proportion between D- and L-lactide determines the morphology of the polymer. For example, PLA resins that have more than 93% L-lactide are semi- crystalline while a PLA resin having 50-93% L-lactide is completely amorphous. In addition, the proportion of different lactides in the polymer influences the glass transition temperature. Suitable PLAs that may be used in the biodegradable polymer emulsion include poly(L- lactide) having predominantly the L- stereoisomer and an amorphous polylactide having a molecular weight between 50,000 and 150,000 g/mole, and in some embodiments between 70,000 and 120,000 g/mole. The concentration of PLA in the biodegradable polymer emulsion may be from about 20% to about 50% of the total weight of the emulsion, and in some embodiments from about 25% to about 35% by weight. Other suitable biodegradable polymers that may be used in the emulsion include, but are not limited to, poly(glycolic acid) (PGA), polycaprolactone (PCL), and polybutylene succinate (PBS).

[0043] Heretofore, emulsions based on PHAs and PLAs utilized organic solvents to emulsify the polymers. In the inventive emulsion, the biodegradable emulsion is typically water-based, which eliminates the presence of an organic solvent in the emulsion. This elimination of organic solvents in turn reduces or eliminates the amount of volatile organic compounds (VOCs) that are emitted into the atmosphere. The amount of volatile organic compounds present in the aqueous emulsion should not exceed about 5,000 ppm. Desirably, the amount of VOCs in the aqueous emulsion is not more than about 1,000 ppm, and in certain embodiments, not more than about 500 ppm. Additionally, the utilization of water reduces the overall cost of the sizing composition as water is a readily available and inexpensive resource. [0044] There are numerous parameters that affect the emulsification of the biodegradable polymer. For instance, the concentration of the polymer, the nature and concentration of the surfactants, the nature and concentration of the plasticizer, and the process conditions can each affect the emulsification process. Choosing an inappropriate surfactant or plasticizer may result in an undesirable or ineffective emulsion or the failure of the polymer to emulsify, resulting in no biodegradable emulsion being formed.

[0045] As is generally known by those of skill in the art, emulsions are heterogeneous mixtures of two or more non-miscible phases (e.g., liquid/liquid dispersion). In the instant invention, a polymer (solid at room temperature) is dispersed in an aqueous phase. Since the dispersion is obtained by a melted biodegradable polymer, the term "emulsion" is utilized herein. Dispersing a liquid into another liquid, such as the melted biodegradable polymer into water, causes the interfacial surface tension to increase. In order to decrease the interfacial surface tension and facilitate the formation of the emulsion, a surfactant may be added during the emulsion process. Generally, one or more surfactants are present in the biodegradable polymer emulsion in an amount from about 2.5% to about 15% by weight of the total components of the emulsion, and in certain embodiments from about 5% to about 10% by weight.

[0046] Non-limiting examples of surfactants suitable for use in the biodegradable polymer emulsion include, but are not limited to, aliphatic, aromatic, and/or halogenated polyalkoxylated derivatives such as ethoxylated/propoxylated alkylphenols, preferably having 1-30 ethylene oxide groups and 0-15 propyleneoxide groups; ethoxylated/propoxylated bisphenols, in certain embodiments having 1-40 ethylene oxide groups and 0-20

propyleneoxide groups; ethoxylated/propoxylated fatty alcohols or esters, in certain embodiments having 8-20 carbon atoms in the alkyl chain, 2-50 ethylene oxide groups and 0- 20 propyleneoxide groups; amine derivatives, alkoxylated amines, amine oxides, alkylamides, succinate derivatives (e.g., potassium or ammonium succinate), phosphate derivatives (e.g., sodium, potassium or ammonium alkylphosphate), ethoxylated fatty acids, esters of fatty acids, and combinations thereof. The polyalkoxylated derivatives may be either block or statistic copolymers. [0047] Further examples of surfactants for use in the present invention are set forth below, where OE represents oxyethylene and OP represents oxypropylene:

• Empilan 2502, HLB = 0, coconut diethanolamide, commercially available from Albright & Wilson

• Synperonic PE/F68, HLB = 29, block copolymer OE/OP, T_meU = 55°C,

commercially available from ICI

• Synperonic PE/L35, HLB = 18.5 block copolymer OE/OP, T_mel, = 55°C, commercially available from ICI

• Genapol O 120, HLB = 13, POE (12) Oleyl Ether (C18), commercially

available from Clariant

• Lutensol AT 80, HLB = 18.5, POE (80) ethoxylated fatty acid (C16-C18), commercially available from BASF

• Brij 76, HLB =12.4, POE(IO) stearyl ether, commercially available from UNIQUEMA

• Brij 78, HLB = 15.3, POE(20) stearyl ether, commercially available from UNIQUEMA

• Brij 700, HLB = 18.8, POE(IOO) stearyl ether, commercially available from UNIQUEMA

• Dermofeel PP, HLB = 9, POE(3) palmitate, . available from Dr. Straetmans

• Ethomeen C25, ethoxylated coconut amine, commercially available from Akzo Nobel

• Igepal CO977, HLB = 18.2, ethoxylated nonyl phenol (50OE), commercially available from Rhodia

[0048] The biodegradable polymer emulsion may also include a plasticizer to reduce the intra-molecular cohesion and reduce the viscosity and melting temperature of the biodegradable polymer. Non-limiting examples of plasticizers for use in the polymer emulsion include polyethylene glycol (PEG) having molecular weights from about 400 to about 10,000 g/mole, in certain embodiments 4,000 to 6,000 g/mole, glycerol triacetate (TAC), tributyl citrate (TBC), bis-2-ethyl hexyl adipate, and mixtures thereof. The plasticizers may be present in the emulsion in an amount from about 5% and 10% by weight of the emulsion, and in certain embodiments in an amount from 5% to 7.5% by weight.

[0049] Further examples of plasticizers for use in forming the inventive emulsion are set forth below:

• PEG 4000 Polyethylene glycol, Mw = 4000 g/mol, T_mei_t = 58°C, commercially available from Merck

• PEG 6000 Polyethylene glycol, Mw = 6000 g/mol, T_melt= 60°C, commercially available from Merck

• Tributyl citrate, sup commercially available from Sigma Aldrich

• Glycerol triacetate, commercially available from Sigma Aldrich

• 2-Ethyl hexyl adipate, commercially available from Sigma Aldrich

[0050] The aqueous biodegradable polymer dispersions are stable over time, are free or substantially free of volatile organic compounds, and have a dry matter content of at least 30%, desirably between about 30% to about 65% by weight of the total dispersion, and more desirably from about 40% to about 60% by weight, hi exemplary embodiments, the dry matter content is from about 50% to about 65% by weight of the total dispersion, hi addition, the biodegradable polymer dispersions have a viscosity at 25 ⁰C between about 30 mPas and about 3,000 mPas, in certain embodiments, between about 50 mPas and about 2,000 mPas, and in some embodiments between about 100 mPas and about 1,000 mPas, as measured by a Brookfield LVF viscosometer. The aqueous polymer emulsions may be characterized by average particle size and particle size distribution. Specifically, the polymer dispersions have an average polymer particle size from about 10 microns to about 150 microns, certain embodiments having a range from about 20 microns to about 100 microns, and are evenly or substantially evenly dispersed throughout the emulsion. The average particle size and the particle size distribution were measured on a Beckman Coulter LS230 laser granulometer.

[0051] The biodegradable polymer film forming emulsion (aqueous polymer dispersion) may be formed in one step by mixing the biodegradable polymer, surfactants, plasticizers, and water in a high pressure reactor under a high stirring rate at a temperature beyond the melting point of the polymer. The term "aqueous polymer dispersion", "biodegradable film forming emulsion", and "biodegradable polymer film forming emulsion" as used interchangeably herein, are meant to denote a colloidal dispersion of polymers in an aqueous phase, i.e., a dispersion of polymer microparticles suspended in an aqueous phase, which may also be termed "polymer suspensions" or "polymer emulsions". When PHB is utilized as the biodegradable polymer, the temperature is raised above 180⁰C (i.e., the melting point of PHB). When PLA is used as the biodegradable polymer, the temperature is raised above 155 ⁰C (Le., the melting point of PLA). The mixture is stirred in the high pressure reactor for 15-45 minutes, depending on the polymer. During the emulsification process, the internal pressure of the reactor is held high and reaches different pressures depending on the emulsions. Once the emulsification process is complete, the reactor is rapidly cooled to avoid the recrystallization of the polymer or a coalescence of micelles (e.g., an aggregate of particles). In exemplary embodiments, the rapid cool down decreases the temperature of the emulsion to approximately 60⁰C within 10 minutes. The cooling of the emulsion can be accomplished by any method known in the art, such as by internal and/or external water cooling systems.

[0052] The biodegradable polymer film forming emulsion is present in the sizing composition in an amount from about 1.0% to about 4.0% by weight of the total components of the size composition, in certain embodiments in an amount from about 1.5% to about 3.0% by weight.

[0053] As discussed above, the biodegradable sizing composition contains at least one coupling agent. Hydrolysable silanes, titanates, zirconates, and mixtures thereof may be used as the coupling agent. Besides their role of coupling the surface of the reinforcement fibers and the plastic matrix, coupling agents also function to reduce the level of fuzz, or broken fiber filaments, during subsequent processing. When needed, a weak acid such as acetic acid, boric acid, metabolic acid, succinic acid, citric acid, formic acid, and/or polyacrylic acid may be added to the size composition to assist in the hydrolysis of the coupling agent. Examples of silane coupling agents that may be used in the size composition may be characterized by the functional groups amino, epoxy, vinyl, methacryloxy, ureido, isocyanato, and azamido. In certain embodiments, the silane coupling agents include silanes containing one or more nitrogen atoms that have one or more functional groups such as amine (primary, secondary, tertiary, and quarternary), amino, imino, amido, imido, ureido, isocyanato, or azamido.

[0054] Non-limiting examples of suitable silane coupling agents include

aminosilanes, silane esters, vinyl silanes, methacryloxy silanes, epoxy silanes, sulfur silanes, ureido silanes, and isocyanato silanes. Specific examples of silane coupling agents for use in the instant invention include γ-aminopropyltriethoxysilane (A-IlOO), n-phenyl-γ- aminopropyltrimethoxysilane (Y-9669), n-trimethoxy-silyl-propyl-ethylene-diamine (A- 1120), methyl-trichlorosilane (A- 154), γ-chloropropyl-trimethoxy-silane (A- 143), vinyl- triacetoxy silane (A- 188), methyltrimethoxysilane (A- 1630), γ-ureidopropyltrimethoxysilane (A- 1524). Other examples of suitable silane coupling agents are set forth in Table 1. All of the silane coupling agents identified above and in Table 1 are available commercially from GE Silicones. In certain embodiments, the silane coupling agent is an aminosilane or a methacryloxy silane.

TABLEl

EXAMPLES OF SILANES

[0055] The size composition may include one or more coupling agents. In addition, the coupling agent(s) may be present in the size composition in an amount from about 0.3% to about 3.0% by weight of the total components in the size composition, in certain embodiments in an amount from about 0.7% to about 2.0 % by weight.

[0056] In addition, the size composition may include at least one lubricant to facilitate fiber manufacturing and composite processing and fabrication. Lubricants assist in the stability of the sizing composition and the wetting of the glass fibers. The lubricant may be present in the size composition in an amount from about 0.4% to about 4.0% by weight of the size composition, in certain embodiments from about 1.0% to about 3.0% by weight.

Although any suitable lubricant may be used, examples of lubricants for use in the sizing composition include, but are not limited to, water-soluble ethyleneglycol stearates (e.g., polyethyleneglycol monostearate, butoxyethyl stearate, polyethylene glycol monooleate, and butoxyethylstearate), ethyleneglycol oleates, ethoxylated fatty amines, glycerin, emulsified mineral oils, organopolysiloxane emulsions, carboxylated waxes, linear or (hyper)branched waxes or polyolefins with functional or non-functional chemical groups, functionalized or modified waxes and polyolefins, nanoclays, nanoparticles, and nanomolecules. .

[0057] Specific examples of lubricants suitable for use in the size composition include stearic ethanolamide, sold under the trade designation Lubesize K- 12 (available from AOC); PEG 400 MO, a monooleate ester having a molecular weight of about 400 g/mole (available from Cognis); Emery 6760L, a polyethyleneimine polyamide salt (available from Cognis); Radiasurf 7473 (PEG 400 monostearate available from Oleon); Antistatico KN (stearyl amido propyl - dimethyl betahydroxyethyl ammonium nitrate available from Sigma Aldrich); and Neoxil AO 83634 (alkyl Ci₆-C₁₈ imidazolinium ethosulphate available from DSM

[0058] The sizing composition used in the present invention may also contain one or more surfactants, dispersants, and plasticizers as a dispersing system. The role of the dispersing system is to enable the formation of an homogenous emulsion, to permit the dispersion of different components of the sizing, to avoid a liquid-liquid phase separation phenomena, and to ensure an effective and rapid wetting during the forming step and impregnation of the glass fibers by the matrix to be reinforced during composite

manufacturing. Plasticizers, surfactants and dispersants often play several roles in the size composition due to the fact that they posses several chemical functions. As a result, their classification into one or another category is difficult. Example of plasticizers, surfactants, and dispersants that may be used in the inventive sizing composition include, but are not limited to:

• organic components:

o aliphatic or aromatic, possibly halogenated, polyalkoxylated derivatives, such as ethoxylated/propoxylated alkylphenols, preferably having 1 to 30 ethylene oxide groups and 0 to 15 propyleneoxide groups; ethoxylated/propoxylated bisphenols, in certain embodiments having 1 to 40 ethylene oxide groups and 0 to 20 propyleneoxide groups and ethoxylated/propoxylated fatty alcohols or esters, in certain embodiments having 8 to 20 carbon atoms in the alkyl chain, 2 to 50 ethylene oxide groups, and 0 to 20 propyleneoxide groups. These polyalkoxylated derivatives may be block or random copolymers.

o amine derivatives, including alkoxylated amines, amine oxides, and

alkylamides

o succinate derivatives, such as potassium or ammonium succinate o phosphate derivatives, such as sodium, potassium or ammonium

alkylphosphate.

• inorganic derivatives, such as silica derivatives. Such components may be used alone or in combination with one of the organic components discussed above.

[0059] The amount of plasticizers, surfactants and dispersants (Le., dispersing system) may be from about 0.1% to about 8.0% by weight of the total sizing composition, and in certain embodiments from about 0.5% to about 5.0% by weight.

[0060] The size composition further includes water to dissolve or disperse the active solids for application onto the reinforcement fibers. Water may be added in an amount sufficient to dilute the aqueous sizing composition to a viscosity that is suitable for its application to the reinforcement fibers and to achieve the desired solids content on the fibers. In particular, the size composition may contain up to about 95% by weight of the total composition of water. [0061] In addition, the size composition may optionally include a pH adjusting agent in an amount sufficient to adjust the pH to a desired level. Suitable pH adjusting agents include weak organic acids such as acetic acid, citric acid, sulfuric acid, or phosphoric acid or a base such as ammonia or sodium hydroxide. The pH may be adjusted depending on the intended application, or to facilitate the compatibility of the ingredients of the size composition. In certain embodiments, the sizing composition has a pH from 3-7, and in some embodiments a pH from 4-5.

[0062] Any additional components or additives of the size composition are chosen among biodegradable products or products that contain low or no toxicity. The sizing composition may optionally contain additives to impose desired properties or characteristics to the size composition and/or to the final composite product. Non-exclusive examples of additives include "sticking agents" (e.g., a polyvinyl acetate emulsion or a polyvinyl alcohol solution), which have the role of ensuring a better cohesion of the strand, UV stabilizers, antioxidants, acid or base capturers, processing aids, antifoaming agents, antistatic agents, thickening agents, adhesion promoters, compatibilizers, flame retardants, impact modifiers, wetting agents, and/or biocides. The additives may be present in the sizing composition in an amount up to about 5% by weight.

[0063] The range of components used in the inventive sizing composition is set forth in Table 2.

TABLE 2: Sizing Composition

[0064] The size composition may be made by adding the silane and deionized water in a container with agitation to hydrolyze the silane coupling agent. As described above, weak acids may be added to assist in hydrolyzing the silane coupling agent. After the hydrolyzation of the silane coupling agent, the film formers, lubricants, and plasticizer/surfactant dispersing system, along with any desired additives, are added to form a mixture. If necessary, the pH of the mixture may be adjusted to a desired level. The film formers and lubricating surfactants (and any additives) may be added separately, or they may be added at the same time to form the main mixture.

[0065] The inventive sizing composition may be used to treat a reinforcing fiber.

Although any type of glass fiber, either biodegradable or non-biodegradable, may be used as the reinforcing fiber. Suitable examples of glass fibers for use in the present invention include, but are not limited to, C-type glass (e.g., C3-type glass), E-type glass, S-type glass, R-type glass, and boron free glass fibers such as Owens Coming's Advantex^® glass fibers are the desired glass fibers. Biodegradable fibers such as C3-type fibers are advantageously employed to form a biodegradable composite product, as is described in detail below. In exemplary embodiments, the reinforcing fiber is C3-type glass or E-type glass. The diameter of the glass fiber can vary, for example, from about 5 μm to about 30 μm.

[0066] The glass fibers may be formed by conventional techniques, such as by drawing molten glass through a heated bushing to form substantially continuous glass fibers. A multitude of these glass fibers may be gathered under the sizing applicator to form glass strands. The linear density of the glass fiber strand can vary widely, such as from about 11 to about 4800 tex, depending on the particular application.

[0067] As used herein, the term "glass strand" is also meant to include derivative products of the glass fibers, in particular, the assembly of the glass strands (formed of glass fibers) into cakes or rovings and the "disassembly" of the glass strands into chopped strands. For example, glass strands may be wound into a forming cake or gathered to form rovings. The rovings may be "direct" rovings having a linear density equivalent to "assembled" (i.e., multi-end) rovings, which may be obtained by gathering the glass fibers under the sizing applicator into strands and winding the strands on a rotating support. Chopped glass strands may be obtained by chopping the glass strands into discrete lengths, such as by a chopping device.

[0068] Water is usually removed by drying the strands after their gathering in the form of cakes or rovings under defined conditions of temperature and duration in order to make it possible to achieve a water content lower than about 0.25%, in certain embodiments lower than about 0.1%. Generally, drying is carried out at a temperature which varies from about 100 °C to about 150 °C for 10 to 20 hours depending on the type of roving and the initial water content, hi the case of chopped strands, the fibers may be dried in an oven at 150 °C for few minutes, generally less than 5 minutes.

[0069] Alternatively, the reinforcing fiber material may be strands of one or more synthetic polymers such as polyester, polyamide, aramid, and mixtures thereof. The polymer strands may be used alone as the reinforcing fiber material, or they can be used in

combination with glass strands such as those described above. As a further alternative, natural fibers may be used as the reinforcing fiber material. The term "natural fiber" as used in conjunction with the present invention refers to plant fibers extracted from any part of a plant, including, but not limited to, the stem, seeds, leaves, roots, or phloem. Examples of natural fibers suitable for use as the reinforcing fiber material include cotton, jute, bamboo, ramie, bagasse, hemp, coir, linen, kenaf, sisal, flax, henequen, and combinations thereof. Carbon or polyaramide fibers may be also used as the reinforcing fiber material.

[0070] The inventive sizing composition may be applied to the reinforcing fibers with a Loss on Ignition (LOI) from 0.3 to 5.0% by weight on the dried fiber, and in certain embodiments from 0.5 to 2.0% by weight. The loss on ignition (LOI) of the reinforcing fibers represents the reduction in weight experienced by the fibers after heating them to a temperature sufficient to burn or pyrolize the organic size from the fibers. As used in conjunction with this application, LOI may be defined as the percentage of organic solid matter deposited on the reinforcement fiber surfaces.

[0071] Reinforcing fibers, such as glass fibers, sized with the biodegradable sizing composition may be used to form composite products by extrusion and/or injection molding processes with a biodegradable or non-biodegradable polymer matrix. Non-limiting examples of suitable biodegradable polymers to be used as a matrix polymer include polylactides (PLAs), polyhydroxyalcanoates (PHAs), polybutylene succinate (PBS), polybutylene adipate terephthalate (PBAT), polycaprolactone (PCL), and combinations thereof. The glass fiber content in the composite may be from about 10 to about 60% by weight of the composite. It is to be understood that the glass fibers are substantially distributed within the polymer matrix forming the composite article. When a biodegradable glass fiber such as a C3-glass fiber is used, the composite product will, over time, eventually completely biodegrade.

[0072] There are numerous advantages provided by the inventive emulsion and sizing composition. For instance, the utilization of water as the solvent in the emulsion eliminates the presence of organic solvents and the emission of volatile organic compounds (VOCs) into the workplace. Heretofore, it has not been known to utilize PLA or PHB in a direct water- based emulsion. In addition, the water-based emulsion is lower in cost than organic solvent- based emulsions, at least in part due to the elimination of the organic solvents and utilization of water. Further, the water-based biodegradable emulsions are stable emulsions with a high dry matter content (e.g., 50 to 65% by weight of the emulsion) and a low viscosity (e.g., below about 100 mPas for PLA emulsions and below about 1000 mPas for PHB emulsions). Additionally, the polymers utilized in the inventive emulsion and sizing composition are advantageously of natural origin. Further, the sizing composition, and when used with a biodegradable polymer matrix and biodegradable reinforcement fiber, produces a composite product that is completely biodegradable.

[0073] Having generally described this invention, a further understanding can be obtained by reference to certain specific examples illustrated below which are provided for purposes of illustration only and are not intended to be all inclusive or limiting unless otherwise specified.

[0074] EXAMPLES

[0075] Emulsion Process Conditions

[0076] Different types of process conditions may be applied to a reactor in order to obtain an emulsion. A Type I procedure includes increasing the temperature until the set point is reached, maintaining the plateau for a certain time, and rapidly cooling of the reactor. A Type II procedure includes increasing the temperature until the set point is reached and immediately cooling the reactor. In both instances, the stirring rate is increased after a certain temperature to increase the shearing and to encourage droplet formation. Generally, for PHB emulsification the Type I procedure was used, and for PLA, a Type II procedure was used. Type I and Type II procedures are illustrated graphically in FIGS. 1 and 2 respectively.

[0077] Example 1: PLA-Based Emulsion [0078] In forming the PLA-based emulsion, a Type II emulsion procedure was utilized. Specifically, 240 g (30%) PLA 7000D, 20 g (2.5%) Empilan 2502, 20 g (2.5%) Synperonic POF68, 60 g (7.5%) PEG 6000, and 460 g deionized water were placed into a reactor and the reactor was tightly closed. A heater was fixed around the reactor and the temperature was set to 160⁰C. The reactor was heated and the mixture stirred at a rate of 1200 rpm. After 35 minutes, when the temperature reached the set point (Le., 160⁰C), the heater was removed and the stirring was reduced to 800 rpm. The emulsion was then cooled using an internal water coil and an external water cooler until the temperature reached 60°C. The average particle size of the polymer particles within the thus formed emulsion was 37 μm. Such a small particle size enables an improved stability of the emulsion and prevents the separation of the emulsion into separate phases.

[0079] Examples 2-10

[0080] PLA-based emulsions containing the components set forth in Tables 3 and 4 were prepared using the procedure set forth in Example 1.

TABLE 3

PLA-Based Emulsions

TABLE 4

PLA-Based Emulsions

[0081] As discussed above with respect to Example 1, the small particle sizes obtained in the PLA-based emulsions improve the stability of the emulsions and prevent the separation of the emulsions into separate phases.

[0082] Example 11: PHB-Based Emulsion

[0083] hi forming the PHB -based emulsion, a Type I emulsion procedure was utilized. Specifically, 128 g (16%) PHB Biocycle 1000, 45 g (7.5%) bis(2-ethyl hexyl) adipate, 45 g (7.5%) Brij 700, and 382 g deionized water were placed into a reactor and the reactor was tightly closed. A heater was fixed around the reactor and the temperature was set to 190⁰C. The reactor was heated and the mixture stirred at 650 rpm for 45 minutes. When the temperature of the reactor reached the set point (Le., 190⁰C), the stirring rate was increased to 1400 rpm and a temperature plateau was maintained for 30 minutes. After 30 minutes, the heater was removed and the stirring rate was decreased to 800 rpm. Next, the emulsion was cooled using an internal water coil and an external water cooler until the temperature dropped to 60 °C. The average particle size of the polymer particles within the emulsion was 45 μm. As with the PLA-based emulsions, the small particle size improves the stability of the emulsion and prevents the separation of the emulsion into separate phases.

[0084] Examples 12-20

[0085] PHB-based emulsions containing the components set forth in Tables 5 and 6 were prepared using the procedure set forth in Example 11.

TABLE 5

PHB-Based Emulsions

TABLE 6

PHB-Based Emulsions

[0086] As discussed above with respect to Example 11, the small particle sizes obtained in the PHB-based emulsions improve the stability of the emulsions and prevent the separation of the emulsions into separate phases.

[0087] Sizing Composition Process Conditions

[0088] Step 1: Each silane present in the size composition was independently hydrolyzed to a minimum of 10 times its volume in deionized water. The pH was adjusted to favor the hydrolysis of methoxy or ethoxy groups to hydroxyl groups and to limit intramolecular condensation reactions. The pH was from 3.5 to 5.0 for all silanes except for γ- aminopropyltriethoxysilane (A-IlOO), which was not acidified. The pH was adjusted by adding acetic acid to achieve an acidic pH. The hydrolysis reaction was conducted at room temperature with constant under stirring for about 20 minutes. [0089] Step 2: If necessary, the silanes were homogenized with additional stirring for about 5 minutes.

[0090] Step 3: The biodegradable polymer emulsion (PLA-based emulsion or PHB- based emulsion) was added to the hydrolyzed silanes by stirring for approximately 30 minutes to form a homogenized mixture.

[0091] Step 4: Add "sticking agents" (e.g., a polyvinyl acetate emulsion) under stirring, if necessary previously diluted if too viscous. Stirring until complete

homogenization, e.g., from about 5 to about 15 minutes.

[0092] Step 5: Desired additives such as lubricants, surfactants, dispersants, anti- foaming agents, and the like, were added with stirring until complete homogenization occurred (about 15-20 minutes).

[0093] Step 6: If the viscosity is too high, thickening agents (e.g., polyvinyl alcohol based) were added to increase the viscosity of the sizing.

[0094] Step 7: A biocide was added to prevent enzymatic degradation of the sized fiber.

[0095] Step 8: Deionized water was added to obtain the desired dry matter content.

[0096] Example 21: Sizing A - PLA-Based Sizing Composition

[0097] To form the PLA-based sizing composition, a first solution was formed by hydrolyzing 126.3 g (0.825%) of 3-methacryloxy propyl trimethoxy silane (A-174) in 2500 g of deionized water by stirring the solution for 30 minutes. The pH of the solution was adjusted to 4.5 by adding 8.3 ml of acetic acid. A second solution was formed by hydrolyzing

43.6 g (0.285%) of glycidoxypropyltrimethoxy silane (A- 187) in 1250 g of deionized water by stirring the solution for 30 minutes. The pH of the solution was adjusted to 4.5 by adding

5 ml of acetic acid.

[0098] The first and second silane solutions were combined and 79 g (0.5%) Simulsol

P4 (a polyethoxylated fatty alcohol) was added to the silane solution and the mixture was stirred for 15 minutes. Next, 1250 g (2.5%) of a PLA-based emulsion as set forth above was added and vigorously stirred for 30 minutes. 269.2 g (0.7%) of Tego Dispers 750W (a dispersing agent), 15 g (0.1%) of Tego Foamex 830 (an anti-foaming agent), 545.45 g (2%) of

Vinamul 8852 (a polyvinyl acetate emulsion (Le., a "sticking agent")), 269.5 g (0.3%) of Emery 6760 (a lubricant), and 7.14 g (0.01%) Acticide MBO (a biocide) was added and thoroughly mixed. Once a homogeneous solution was obtained, 8631.5 g of deionized water was added to obtain a dry matter content of 7.22%. The mixture was stirred at a moderate stirring rate for a minimum of 6 hours.

[0099] Example 22; Sizing B - PHB-Based Sizing Composition

[00100] To form the PHB-based sizing composition, a first solution was formed by hydrolyzing 126.3 g (0.825%) of γ-glycidoxypropyltrimethoxysilane (A-187) in 2500 g of deionized water by stirring the solution for 30 minutes. The pH of the solution was adjusted to 4.5 by adding 6.7 ml of acetic acid. A second solution was formed by hydrolyzing 43.6 g

(0.285%) of γ-aminopropyltriethoxysilane (A-IlOO) in 834 g of deionized water by stirring the solution for 30 minutes. The pH of the solution was approximately 11.0.

[00101] The first and second silane solutions were combined and 79 g (0.5%) Simulsol

P4 (a polyethoxylated fatty alcohol) was added to the silane solution and the mixture was stirred for 15 minutes. Next, 2344 g (2.5%) of a PHB-based emulsion as set forth above was added and vigorously stirred for 30 minutes. 384.6 g (1.0%) of Tego Dispers 750W (a dispersing agent), 15 g (0.1%) of Tego Foamex 830 (an anti-foaming agent), 545.45 g (2%) of

Vinamul 8852 (a polyvinyl acetate emulsion (i.e., a "sticking agent")), 269.5 g (0.3%) of

Emery 6760 (a lubricant), and 7.14 g (0.01%) Acticide MBO (a biocide) was added and thoroughly mixed. Once a homogeneous solution was obtained, 8230 g of deionized water was added to obtain a dry matter content of 6.5%. The mixture was stirred at a moderate stirring rate for a minimum of 6 hours.

[00102] Sizing compositions containing PLA- and PHB-based emulsions are presented in Table 7 and Table 8, respectively.

TABLE 7

Sizing Compositions For C3-glass Fibers

TABLE 8

Sizing Compositions For E-glass Fibers

[00103] The tensile strength of the obtained fibers was determined to be between 0.28 and 0.43 N/tex for C3-glass fibers, and between 0.52 and 0.56 N/tex for E-glass fibers. The density of the chopped strands was between 0.38 and 0.47.

[00104] The invention of this application has been described above both generically and with regard to specific embodiments. Although the invention has been set forth in this application, a wide variety of alternatives known to those of skill in the art can be selected within the generic disclosure. The invention is not otherwise limited, except for the recitation of the claims set forth below.

Claims

1. An aqueous sizing composition comprising:

a biodegradable polymer emulsion, said biodegradable polymer emulsion including at least one biodegradable polymer emulsified in water;

at least one silane coupling agent;

at least one lubricant;

a dispersing system including at least one member selected from a plasticizer, dispersant and a surfactant; and

water.

2. The aqueous sizing composition of claim 1, wherein said biodegradable polymer is selected from polylactides, poly(glycolic acid), polycaprolactone, polybutylene succinate, polyhydroxyalcanoates and combinations thereof.

3. The aqueous sizing composition of claim 2, wherein said at least one silane coupling agent is selected from an aminosilane, a methacryloxy silane and mixtures thereof.

4. The aqueous sizing composition of claim 2, wherein said biodegradable polymer emulsion has an average particle size from about 10 microns to about 150 microns.

5. The aqueous sizing composition of claim 2, wherein said biodegradable polymer emulsion has a dry matter content of at least 30%.

6. The aqueous sizing composition of claim 2, wherein:

said biodegradable polymer emulsion is present in said sizing composition in an amount from 1% to about 8% by weight of the total weight of said sizing composition;

said at least one silane coupling agent is present in said sizing composition in an amount from 0.3% to about 3% by weight of the total weight of said sizing composition; said at least one lubricant is present in said sizing composition in an amount from 0.4% to about 4% by weight of the total weight of said sizing composition; and said dispersing system is present in said sizing composition in an amount from 0.1% to about 5% by weight of the total weight of said sizing composition.

7. A sized reinforcement fiber comprising:

a reinforcement fiber at least partially coated with a sizing composition including: a biodegradable polymer emulsion, said biodegradable polymer emulsion including at least one biodegradable polymer of natural origin emulsified in water;

at least one silane coupling agent;

at least one lubricant;

water.

8. The sized reinforcement fiber of claim 7, wherein said biodegradable polymer is selected from polylactides, poly(glycolic acid), polycaprolactone, polybutylene succinate, polyhydroxyalcanoates and combinations thereof.

9. The sized reinforcement fiber of claim 8, wherein said biodegradable polymer is selected from polyhydroxyalcanoates, polylactides and mixtures thereof.

10. The sized reinforcement fiber of claim 7, wherein said biodegradable polymer emulsion has a dry matter content of at least 30%.

11. The sized reinforcement fiber of claim 8, wherein said biodegradable polymer emulsion has an average particle size from about 10 microns to about 150 microns, said particles being substantially evenly dispersed in said biodegradable polymer emulsion.

12. A fiber reinforced composite article comprising:

a biodegradable polymer matrix; and

a plurality of reinforcing fibers substantially evenly distributed within said polymer matrix, said reinforcing fibers being at least partially coated with a sizing composition including:

a biodegradable polymer emulsion, said biodegradable polymer emulsion including at least one biodegradable polymer of natural origin emulsified in water;

at least one silane coupling agent;

at least one lubricant;

water.

13. The fiber reinforced composite article of claim 12, wherein said biodegradable polymer is selected from polyhydroxyalcanoates, polylactides and mixtures thereof.

14. The fiber reinforced composite article of claim 13, wherein said reinforcing fiber is a biosoluble fiber and said reinforced composite article is biodegradable.

15. The fiber reinforced composite article of claim 12, wherein said biodegradable polymer emulsion has an average particle size from about 10 microns to about 150 microns, said particles being substantially evenly dispersed in said biodegradable polymer emulsion.

16. The fiber reinforced composite article of claim 15, wherein said biodegradable polymer emulsion has a dry matter content of at least 30%.