JP2007291240A - Biomass particle and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a biomass particle which is an additive for obtaining a molded product which is excellent in recyclability, biodegradability and disposability and is capable of retaining a high biobased content, which is the original purpose of a biomass material, and improving impact resistance, which is an issue to be solved in the biomass material. <P>SOLUTION: The biomass particle is obtained through polycondensation of a polycondensable monomer containing at least lactic acid in an aqueous medium, wherein the average particle size of the biomass particle is ≤10 μm. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to biomass particles and a method for producing the same, and more particularly to biomass particles that are additives as an impact strength improver for a molded biomass and a method for producing the same.

In recent years, plant-derived biomass materials have been actively developed from the viewpoints of environmental problems such as global warming, oil depletion, waste problems, and the concept of building a sustainable recycling society.
For example, polylactic acid is attracting attention as a biomass material produced from cereals and the like without using any petroleum, and is used for applications such as agricultural sheets and household garbage bags.
However, polylactic acid has problems such as being hard and brittle and having low heat resistance, and thus its use has been remarkably limited. Therefore, attempts have been made to use it as a casing for walkmans and notebook personal computers by blending with a petroleum-based resin material having plasticity and heat resistance (see Patent Document 1 and Patent Document 2).
However, in the conventional petroleum resin blend system, the plant degree (content of plant-derived material) of the material is low, and the original purpose of the biomass material cannot be sufficiently fulfilled.

  On the other hand, brittleness is improved by using nucleating agents such as clay and kenaf, and increasing the mold temperature during molding, and biaxially stretching the film once to crystallize polylactic acid. However, attempts have been made to use it for package films such as meal trays, DVDs, and CD-ROMs (see Patent Document 3). In this method, since it is difficult to separate the crystal nucleating agent used, there is a problem that the recyclability is inferior, and even when discarded, biodegradation disposal cannot be made 100%.

JP-A-2005-48066 JP 2004-190026 JP JP 2001-244645 A

  The purpose of the present invention is to maintain the plantiness, which is the original purpose of the biomass material, to improve the impact strength, which is a problem of the biomass material, and to obtain a molded article excellent in recyclability and biodegradability disposal It is in providing the biomass particle | grains which are additives, and its manufacturing method.

The object is achieved by the means described in <1> or <2>.
<1> Biomass particles obtained by polycondensing a polycondensable monomer containing at least lactic acid in an aqueous medium, wherein the biomass particles have an average particle diameter of 10 μm or less. ,
<2> An average particle size of 10 μm, comprising a step of dispersing an oil phase containing a polycondensable monomer containing at least lactic acid in an aqueous medium and a step of polycondensing the polycondensable monomer. The manufacturing method of the biomass particle | grains which are the following.

  According to the present invention, in order to maintain the plant degree which is the original purpose of the biomass material, improve the impact strength which is a problem of the biomass material, and obtain a molded article excellent in recyclability and biodegradability disposal. It is possible to provide biomass particles that are additives. Furthermore, according to this invention, the manufacturing method of the said biomass particle can be provided.

The biomass particles of the present invention are biomass particles obtained by polycondensation of a polycondensable monomer containing at least lactic acid in an aqueous medium, wherein the biomass particles have an average particle size of 10 μm or less. And
In the present invention, biomass means a biological resource, and among these, a plant-derived biological resource. Examples of biomass raw materials include sugar cane, corn, and potato, but are not limited thereto. The biomass particles of the present invention contain 50 parts by weight or more of lactic acid which is biomass when the total amount of the polycondensable monomer is 100 parts by weight.

When used as a molding material, polylactic acid, which is a representative biomass material, has a problem that it is brittle, that is, has low impact strength. Introducing fine particles as a nucleating agent to promote crystallization during molding is effective in improving the impact strength of polylactic acid.
However, since many things conventionally used as a nucleating agent, such as glass fiber and carbon fiber, are not derived from plants and do not have biodegradability, the effect of reducing the environmental load is reduced. Moreover, even if it is going to be recycled or biodegraded and discarded, it is necessary to separate the nucleating agent, and this separation is extremely difficult. That is, it is inferior in recyclability and biodegradability disposal.
In consideration of the environment, there are also cases where natural fillers such as kenaf and mica are used, but the compatibility with polylactic acid is not always sufficient and the dispersion becomes non-uniform, which has the effect of improving impact strength. Not enough.

The biomass particles of the present invention are obtained by polycondensation of a polycondensable monomer containing at least lactic acid. Therefore, naturally the compatibility with polylactic acid is very high. As a result, the biomass particles of the present invention are very uniformly dispersed in polylactic acid, and a large impact strength improvement effect is obtained. Therefore, the biomass particles of the present invention are suitably used as a nucleating agent added to improve the impact strength strength of polylactic acid.
The biomass particles of the present invention can be blended with resins other than polylactic acid or polycondensable monomers other than lactic acid, which are effective in improving impact strength and other properties required for molded products, if necessary. Resin particles copolymerized with the monomer may be used.

The average particle diameter of the biomass particles of the present invention is 10 μm or less. When the average particle diameter exceeds 10 μm, the volume becomes too large, and the crystallization of polylactic acid is hindered. If it is 10 μm or less, crystallization of polylactic acid is promoted.
The average particle size of the biomass particles of the present invention is preferably 3 μm or less, and more preferably 1 μm or less. In particular, when the average particle size is 1 μm or less, the surface area effect as a nucleating agent is dramatically increased, the impact strength can be improved by adding a very small amount, and the crystallization rate of polylactic acid is remarkably increased. This is preferable because the molding cycle can be greatly shortened.
The average particle diameter of biomass particles means a number average particle diameter, and can be measured by a laser diffraction particle size distribution measuring device (manufactured by Sysmex Corporation, Master Kaiser 2000).

The biomass particles of the present invention preferably have a narrow particle size distribution. Specifically, the volume average particle size distribution index GSDv is preferably 1.4 or less. More preferably, GSDv is 1.3 or less.
The volume average particle size distribution index GSDv is obtained as follows. That is, the cumulative distribution is drawn from the small diameter side for the volume for the particle size range (channel) divided on the basis of the particle size distribution, the particle size that becomes 16% cumulative is the volume D _16v , and the particle size that becomes the cumulative 84% is the volume D. _It is defined as _84v . Using these, the volume average particle size distribution index (GSDv) is calculated by the following equation.
GSDv = ( _D84v / _D16V ) ^1/2
A GSDv of 1.4 or less is preferable because the particle size distribution is uniform and the biomass particles of the present invention can be uniformly dispersed in polylactic acid.
The volume average particle size distribution index GSDv can be measured using a laser diffraction type particle size distribution measuring apparatus or the like.

Moreover, the biomass particles of the present invention preferably have a shape factor SF1 of 100 to 125, and more preferably 100 to 120. When the shape factor SF1 is within the above range, the dispersibility in the resin is improved and the flow at the time of injection molding is improved, which is preferable.
The shape factor SF1 is calculated as follows.

ここでＭＬ：粒子の絶対最大長、Ａ：粒子の投影面積である。
これらは、主に顕微鏡画像又は走査電子顕微鏡画像をルーゼックス画像解析装置によって取り込み、解析することによって数値化される。

Here, ML is the absolute maximum length of the particle, and A is the projected area of the particle.
These are quantified mainly by capturing and analyzing a microscope image or a scanning electron microscope image with a Luzex image analyzer.

The weight average molecular weight (Mw) of the biomass particles of the present invention is preferably 5,000 to 200,000, and more preferably 8,000 to 50,000. A weight average molecular weight of 5,000 or more is preferred because the impact strength of the biomass particles themselves tends to increase. Moreover, it is preferable for the weight average molecular weight to be 200,000 or less because it tends to form particles.
A weight average molecular weight can be measured as a styrene conversion weight average molecular weight by a gel permeation chromatograph (manufactured by Tosoh Corporation, HLC-8220GPC).
In addition, the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is preferably 1 to 3, and more preferably 1.5 to 2.5. Here, Mw / Mn is an index representing the molecular weight distribution. When Mw / Mn is close to 1, it means that the molecular weight distribution is narrow, and when Mw / Mn is large, it means that the molecular weight distribution is wide.
It is preferable that Mw / Mn is within the above range because the molecular weight distribution is narrow and the variation in mechanical strength of the particles themselves is reduced.

The biomass particles of the present invention preferably have a melting point of 140 to 350 ° C, more preferably 160 to 250 ° C. It is preferable that the melting point is in the above-mentioned range since it can exhibit appropriate adhesiveness with the resin material while being independent as particles.
This melting point can be determined as the melting peak temperature of input compensated differential scanning calorimetry based on JIS K-7121: 87. The crystalline resin may show a plurality of melting peaks, but in the present invention, the maximum peak is regarded as the melting point.

Next, the manufacturing method of the biomass particle | grains of this invention is demonstrated. The method for producing biomass particles of the present invention includes a step of dispersing an oil phase containing a polycondensable monomer containing at least lactic acid in an aqueous medium (hereinafter also referred to as “emulsification step”) and a polycondensable single amount. Characterized in that it comprises a step of polycondensing the body (hereinafter also referred to as “polycondensation step”).
Biomass materials obtained by polycondensation of a polycondensable monomer that usually contains lactic acid are difficult to make into fine particles. In order to make fine particles, for example, there is usually a method of pulverizing cylindrical pellets having a length of 3 to 10 mm and a diameter of 2 to 3 mm. However, biomass materials such as polylactic acid have low heat resistance. It causes fusion and cannot be made into fine particles.
In order to make polyester into particles, there is a means called emulsion polymerization, but this method has high monomer selectivity, and fine particles cannot be obtained when lactic acid is used as a polycondensable monomer in the usual method.
According to the method for producing biomass particles of the present invention, finely divided biomass particles having an average particle diameter of 10 μm or less are obtained.

In the present invention, polycondensation of a polycondensable monomer containing at least lactic acid is performed in an aqueous medium.
Here, as an aqueous medium which can be used for this invention, water, such as distilled water and ion-exchange water, alcohols, such as ethanol and methanol, etc. are mentioned, for example. Among these, ethanol and water are preferable, and water such as distilled water and ion-exchanged water is particularly preferable. These may be used individually by 1 type and may use 2 or more types together.
The aqueous medium may contain a water-miscible organic solvent. Examples of the water-miscible organic solvent include acetone and acetic acid.

The method for producing biomass particles of the present invention includes a step of preparing an emulsified dispersion in which an oil phase containing at least a polycondensable monomer is emulsified and dispersed in an aqueous medium. In the present invention, the polycondensable monomer contains at least lactic acid.
Here, in order to form a particle emulsion, for example, a solution containing at least a polycondensable monomer to which a co-surfactant is added (oil phase) and an aqueous solution of a surfactant (aqueous phase) are mixed with a piston homogenizer, The mixture is uniformly mixed and emulsified by a shear mixing device such as a microfluidizer (eg, Microfluid, “Microfluidizer” manufactured by Dix) or an ultrasonic disperser. In that case, it is preferable that the preparation amount of the oil phase with respect to the water phase is about 0.1 to 50% by weight with respect to the total amount of the water phase and the oil phase. The amount of the surfactant used is preferably less than the critical micelle concentration (CMC) in the presence of the emulsion to be formed, and the amount of the cosurfactant used is preferably 100 parts by weight of the oil phase. Is 0.1 to 40 parts by weight, more preferably 0.1 to 20 parts by weight.
The “mini-emulsion polymerization method”, which is a polymerization of the monomer emulsion in the presence of a polymerization initiator of the monomer emulsion by the combined use of the surfactant amount less than the critical micelle concentration (CMC) and the co-surfactant, Since monomer is polymerized in monomer particles (oil droplets), uniform polymer particles are formed, which is preferable. Further, the “miniemulsion polymerization method” has an advantage that the polymer can exist in the polymer particles as it is because diffusion of the monomer is unnecessary in the polymerization process.

  Also, for example, J. Org. S. Guo, M .; S. El-Asser, J.A. W. Vanderhoff; Polym. Sci. : Polym. Chem. Ed. 27, 691 (1989), etc., so-called “microemulsion polymerization” of particles having a particle diameter of 5 to 50 nm has the same dispersion structure and polymerization mechanism as “miniemulsion polymerization” in the present invention. It can be used in the present invention. “Microemulsion polymerization” uses a large amount of a surfactant having a critical micelle concentration (CMC) or more, and a large amount of the surfactant is mixed in the resulting polymer particles or for the removal thereof. In addition, there may be a problem that a great amount of time is required for processes such as water cleaning, acid cleaning, or alkali cleaning.

The method for producing a resin particle dispersion of the present invention includes a step of polycondensing a polycondensable monomer in an aqueous medium.
In the case of the present invention, the monomer is dispersed in an aqueous medium in which a small amount of a surfactant, a co-surfactant and the like are dissolved as necessary using mechanical shearing force, ultrasonic waves, etc. Perform condensation. In addition, the monomer is dissolved in another medium, and if necessary, an oil phase in which a surfactant, a co-surfactant and the like are dissolved is prepared, dispersed in the aqueous medium, heated, and heated. Perform condensation. As a polymerization method in this case, a suspension polymerization method, a mini-emulsion method, a microemulsion method, an emulsion polymerization method including a multistage swelling method and a seed polymerization, or a resin such as urethane was used as a method for polymerizing particles in an aqueous medium. It is possible to use a heterogeneous polymerization form in a normal aqueous medium such as an extension reaction method. Among these polymerization methods, the microemulsion method and the miniemulsion polymerization method are preferably used, and the miniemulsion polymerization method is most preferable because a uniform particle size is obtained and the particle size distribution is easily uniform.

  In polycondensation in an aqueous medium, the polycondensable monomer and the catalyst interact with each other on the surface of the oil droplet produced in the aqueous phase. Insufficient balance may adversely affect reactivity such as insufficient polycondensation in addition to particle destabilization. When the monomer is polycondensed on the surface, the polycondensate is drawn into the particle according to the newly developed hydrophobic property, and it can be predicted that a hydrophilic low polymerization degree component appears on the surface instead. This reaction is based on the degree of polymerization of the polycondensate, and the substance moves inside the particles. Furthermore, since polycondensation is possible at a very low temperature, not only the generation of impurities and by-products can be suppressed, but also low The molecular weight component can be reduced as compared with bulk polymerization, and the composition distribution of the degree of polymerization can be controlled uniformly.

  Control of polycondensation in an aqueous medium can be achieved by controlling the properties of the catalyst used and the monomer used. For example, as the catalyst, a surfactant type catalyst having both properties of a surface activity and a polycondensation catalyst can be preferably used. In this case, as described above, since the polycondensation catalyst is present on the surface of the oil droplets formed in the aqueous medium, the diffusion of the monomer into the aqueous phase is suppressed, and the particle surface is the performance of the surfactant. It can be presumed that hydrolysis by water can be suppressed by being covered with a catalyst having A. That is, the surface of the oil droplet is in a state close to bulk polymerization. Therefore, there is no diffusion to the aqueous phase and particle generation in the aqueous phase due to it, as observed in emulsion polymerization, etc., and the resulting polyester acts as a co-surfactant in so-called miniemulsion polymerization. In order to prevent Ostwald ripening, the particle size can be adjusted, the particle size can be maintained during the particle production process, and the particle size distribution can be narrowed.

In the present invention, it is preferable to use a polycondensable catalyst in the polycondensation reaction, and examples of the polycondensable catalyst include a surfactant type catalyst, a metal catalyst, and a hydrolase type catalyst.
Examples of surfactant-type catalysts include strong acids having surface-active effects, such as alkyl benzene sulfonic acids such as dodecylbenzene sulfonic acid, isopropyl benzene sulfonic acid, camphor sulfonic acid, paratoluene sulfonic acid, alkyl sulfonic acid, alkyl Disulfonic acid, alkylphenol sulfonic acid, alkylnaphthalene sulfonic acid, alkyltetralin sulfonic acid, alkylallyl sulfonic acid, petroleum sulfonic acid, alkylbenzimidazole sulfonic acid, higher alcohol ether sulfonic acid, alkyl diphenyl sulfonic acid, monobutylphenyl phenol sulfuric acid, dibutyl Higher fatty acid sulfates such as phenylphenol sulfate and dodecyl sulfate, higher alcohol sulfates, higher alcohol ether sulfates, higher fatty acid esters Door alkylol sulfate, higher fatty acid amide alkylated sulfate, naphthenyl alcohol sulfate, sulfated fat, sulfosuccinate, various fatty acids, sulfonated higher fatty acid, higher alkyl phosphate, resin acid, resin acid alcohol sulfate, naphthenic acid , Niobic acid, and all salt compounds thereof, for example, the following salt compounds with rare earth metals can be used, but are not limited thereto. A plurality of these may be combined as necessary. Of these, the surfactant type catalyst preferably used includes dodecylbenzenesulfonic acid, isopropylbenzenesulfonic acid, camphorsulfonic acid and the like.
In the present invention, it is particularly preferable to use a surface active catalyst having a sulfonic acid group.

Examples of the metal catalyst include, but are not limited to, the following. For example, an organic tin compound, an organic titanium compound, an organic tin halide compound, and a rare earth metal catalyst can be used. Specific examples of the rare earth-containing catalyst include lanthanoid elements such as lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), Those containing terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), etc. are effective. Of these, alkylbenzene sulfonates, alkyl sulfate esters, and those having a triflate structure are particularly effective. Examples of the triflate include X (OSO ₂ CF ₃ ) _{3 in} the structural formula. Here, X is a rare earth element, and among these, the triflate is more preferably the following compound. That is, X is preferably scandium (Sc), yttrium (Y), ytterbium (Yb), samarium (Sm), or the like.
Also preferred are lanthanoid triflates. The lanthanoid triflate is detailed in the Journal of Synthetic Organic Chemistry, Vol. 53, No. 5, p44-54).

  The hydrolase type catalyst is not particularly limited as long as it catalyzes an ester synthesis reaction. Examples of the hydrolase in the present invention include EC (enzyme number) 3.1 group such as carboxyesterase, lipase, phospholipase, acetylesterase, pectinesterase, cholesterol esterase, tannase, monoacylglycerol lipase, lactonase, lipoprotein lipase and the like. (See Maruo and Tamiya's “Enzyme Handbook” Asakura Shoten (1982), etc.) Hydrolase and epoxide classified as EC 3.2 that act on glycosyl compounds such as esterase, glucosidase, galactosidase, glucuronidase, and xylosidase. EC3.4 group that acts on peptide bonds such as hydrolase, aminopeptidase, chymotrypsin, trypsin, plasmin, subtilisin, etc. classified into EC3.3 group such as hydrase Hydrolase class, can be mentioned hydrolases such classified into EC3.7 group such as furo retinoic hydrolase.

  Among the above esterases, enzymes that hydrolyze glycerol esters and liberate fatty acids are called lipases, but lipases are highly stable in organic solvents, catalyze ester synthesis reactions in high yields, and are even cheaper. There are advantages such as availability. Therefore, also in the manufacturing method of polyester of this invention, it is preferable to use a lipase from the surface of a yield or cost.

  Lipases of various origins can be used, but preferred are genus Pseudomonas, genus Alcaligenes, genus Achromobacter, genus Candida, genus Aspergillus, lysopus Examples include lipases obtained from microorganisms such as (Rhizopus) genus and Mucor genus, lipases obtained from plant seeds, lipases obtained from animal tissues, pancreatin, steapsin and the like. Among these, it is preferable to use lipases derived from microorganisms of the genus Pseudomonas, Candida, and Aspergillus.

In order to achieve polycondensation at a lower temperature in the above catalyst, a surfactant type catalyst, a rare earth element catalyst, and an enzyme catalyst are effective. As the rare earth metal catalyst, it is particularly preferable to use a catalyst having Y, Sc, Yb, Sm or the like as its constituent components.
It should be noted that it is preferable to select a polycondensable catalyst having a higher hydrophobicity or molecular weight in view of the fact that the catalyst is distributed in the emulsion or particles of the polycondensable resin being polymerized and the aqueous medium. It is particularly preferable to select a surfactant type catalyst.
At this time, the addition amount of the catalyst is preferably 0.1 to 100,000 ppm with respect to the polycondensable monomer, and preferably 0.1 to 80,000 ppm. More preferred. At this time, one type or a plurality of types can be added.
The polycondensable catalyst can be added to either the aqueous phase or the oil phase, but is preferably added to the aqueous phase. In particular, in the miniemulsion polymerization method, it is preferably added to the aqueous phase.

In the present invention, at least lactic acid is used as the polycondensable monomer. The polycondensable monomer that can be used in combination is preferably an aliphatic hydroxyalkanoate. The aliphatic hydroxyalkanoate has a structure in which a hydroxyl group is substituted for an aliphatic alkanoic acid. The aliphatic alkanoic acid may have any of a branched structure, a straight chain structure, and an alicyclic structure, but preferably has a branched or straight chain structure, and has a straight chain structure. Is more preferable.
The number of carbon atoms is preferably 1-30, more preferably 2-8. Examples of aliphatic hydroxyalkanoates include β-hydroxybutyric acid, hydroxyacetic acid, 4-hydroxybutyrate, 4-hydroxy-2- Examples thereof include methyl butyrate and 6-hydroxyhexanoate, and β-hydroxybutyric acid is preferable.
The aliphatic hydroxyalkanoate used in combination is preferably 5 to 70 parts by weight, more preferably 10 to 60 parts by weight with respect to 100 parts by weight of lactic acid. It is preferable that the amount of hydroxyalkanoate used in combination is within the above range because the compatibility of the particles themselves with the polylactic acid material is improved.
In the present invention, when the total amount of the polycondensable monomer is 100 parts by weight, it contains 50 parts by weight or more of lactic acid, and more preferably 60 parts by weight or more.

  In the present invention, it is preferable to obtain biomass particles using a surface active catalyst having a sulfonic acid group as a catalyst and using lactic acid and an aliphatic hydroxyalkanoate as a polycondensable monomer.

Examples of the polycondensable monomer used in combination with other lactic acid include, for example, aliphatic, alicyclic and aromatic polycarboxylic acids and alkyl esters thereof, polyhydric alcohols and ester compounds thereof, and Examples thereof include polyvalent amines, which can be polymerized by direct esterification reaction, transesterification reaction or the like.
It is also preferable to use a polycarboxylic acid and a polyol in combination as the polycondensable monomer.

  A polycarboxylic acid is a compound containing two or more carboxyl groups in one molecule. Among these, dicarboxylic acid is a compound containing two carboxyl groups in one molecule, and it is preferable to use dicarboxylic acid as polycarboxylic acid. Examples of dicarboxylic acids include oxalic acid, succinic acid, maleic acid, malonic acid, glutaric acid, adipic acid, β-methyladipic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, decanedicarboxylic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid Acid, fumaric acid, citraconic acid, itaconic acid, diglycolic acid, cyclohexane-3,5-diene-1,2-carboxylic acid, malic acid, citric acid, hexahydroterephthalic acid, malonic acid, pimelic acid, tartaric acid, mucus Acid, phthalic acid, isophthalic acid, terephthalic acid, tetrachlorophthalic acid, chlorophthalic acid, nitrophthalic acid, p-carboxyphenylacetic acid, p-phenylenediacetic acid, m-phenylenediglycolic acid, p-phenylenediglycolic acid, o- Phenylene diglycolic acid, diphenylacetic acid, di Eniru -p, p'-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, and anthracene dicarboxylic acid. Examples of the polycarboxylic acid other than dicarboxylic acid include trimellitic acid, trimesic acid, pyromellitic acid, naphthalenetricarboxylic acid, naphthalenetetracarboxylic acid, pyrenetricarboxylic acid, and pyrenetetracarboxylic acid.

The polyhydric alcohol (polyol) as a polycondensable monomer that can be used in the present invention is a compound containing two or more hydroxyl groups in one molecule. Among these, the diol is a compound containing two hydroxyl groups in one molecule. For example, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butane diol, butene diol, neopentyl glycol, pentane glycol, hexane diol, Examples include cyclohexanediol, cyclohexanedimethanol, dipropylene glycol, octanediol, nonanediol, decanediol, dodecanediol, bisphenol A, bisphenol Z, and hydrogenated bisphenol A. Examples of polyols other than diols include, but are not limited to, glycerin, pentaerythritol, hexamethylol melamine, hexaethylol melamine, tetramethylol benzoguanamine, and tetraethylol benzoguanamine.
Examples of the polyol that can be used in the present invention include 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decane among the above polyols. It is preferable to use a diol such as a diol or 1,12-dodecanediol. Preferred examples of the polyol other than the divalent polyol include glycerin, pentaerythritol, hexahydroxymethyl melamine, hexahydroxyethyl melamine, tetrahydroxymethyl benzoguanamine, and tetrahydroxyethyl benzoguanamine.

Furthermore, in this invention, it is preferable to have 0.1-40 wt% of cosurfactant with respect to the total amount of monomers. Co-surfactants are added to reduce Ostwald ripening in so-called miniemulsion polymerization. As the co-surfactant, those known as co-surfactants for the mini-emulsion method can be generally used.
Examples of suitable co-surfactants include alkanes having 8 to 30 carbon atoms such as dodecane, hexadecane and octadecane, alkyl alcohols having 8 to 30 carbon atoms such as lauryl alcohol, cetyl alcohol and stearyl alcohol, lauryl mercaptan, C8-C30 alkanethiols such as cetyl mercaptan, stearyl mercaptan, and others, acrylic esters and methacrylic esters and their polymers, polymers such as polystyrene and polyester, polyadducts, carboxylic acids, and ketones Amines and the like, but is not limited thereto.

Among the co-surfactants exemplified above, those preferably used are hexadecane, cetyl alcohol, stearyl methacrylate, lauryl methacrylate, polyester, and polystyrene. In particular, stearyl methacrylate, lauryl methacrylate, polyester, and polystyrene are more preferable for the purpose of avoiding the generation of volatile organic substances.
The polymer and the composition containing a polymer that can be used for the cosurfactant can include, for example, a copolymer with another monomer, a block copolymer, a mixture, and the like. A plurality of co-surfactants can also be used in combination.
The co-surfactant can be added to both the oil phase and the aqueous phase.

The biomass particles of the present invention are preferably added to a polylactic acid resin and used as a nucleating agent. The mechanical strength of polylactic acid can be increased by adding biomass particles to the polylactic acid resin and kneading.
The biomass particles are preferably added in an amount of 1 to 50 parts by weight, more preferably 5 to 20 parts by weight, based on 100 parts by weight of the polylactic acid resin. The addition amount within the above range is preferable because the mechanical strength of the polylactic acid resin increases and the heat resistance does not decrease.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely using an Example, this invention is not limited at all by these.

Example 1
In a 1 L three-necked flask, 5 parts by weight of dodecylbenzenesulfonic acid was mixed with 1,000 parts by weight of ion-exchanged water and dissolved. 100 parts by weight of lactic acid and 60 parts by weight of β-hydroxybutyric acid were mixed in this, heated to 110 ° C. and dissolved, and emulsified for 10 minutes with a homogenizer (Ultra Tax, manufactured by IKA). After emulsification for 10 minutes in the flask, the emulsion was maintained at 70 ° C. in a flask while stirring, and further maintained for 20 hours.
Thereby, biomass particles (1) having an average particle diameter of 2 μm were obtained.

The obtained biomass particles (1) were measured for weight average molecular weight (Mw), weight average molecular weight (Mw) to number average molecular weight (Mn) ratio (Mw / Mn), melting point (Tm), shape factor SF1, GSDv. The results are shown in Table 1.
The weight average molecular weight and Mw / Mn were measured by gel permeation chromatograph (manufactured by Tosoh Corporation, HLC-8220GPC).
The melting point was determined as the melting peak temperature of input compensated differential scanning calorimetry (Perkin Elmer, Diamond DSC) based on JIS K-7121: 87. The crystalline resin may show a plurality of melting peaks, but the maximum peak was regarded as the melting point.
The shape factor SF1 of the biomass particles was obtained as follows. First, an optical microscope image of biomass particles spread on a slide glass is taken into a Luzex image analyzer through a video camera, and the absolute maximum length (ML) and projected area (A) of 50 biomass particles are measured. From the formula 1, the shape factor SF1 of the biomass particles was determined.
Further, the cumulative volume average particle size D ₅₀ and the volume average particle size distribution index GSDv of the biomass particles of the present invention were divided based on the particle size distribution measured by a Coulter Multisizer II (manufactured by Beckman-Coulter). A cumulative distribution is drawn from the small diameter side with respect to the particle size range (channel), and the particle size to be accumulated 16% is the volume D _16v , the number D _16P , the particle size to be accumulated 50% is the volume D _50v , A particle size that is a number D _50P and a cumulative 84% is defined as a volume D _84v and a number D _84P . Using these, the volume average particle size distribution index (GSDv) is calculated as (D _84v / D _16V ) ^1/2 and the number average particle size distribution index (GSDp) is calculated as (D _84P / D _16P ) ^1/2 . The aperture diameter to be used needs to be changed depending on the size of the target particle. If the target particle size is 1 to 3 μm, the aperture diameter is 30 μm, and if it is 3 to 7 μm, the aperture diameter is 50 μm, 7 The aperture diameter was 100 μm when the thickness was −10 μm.

  10 parts by weight of the obtained biomass particles (1) and 90 parts by weight of a polylactic acid resin (manufactured by Mitsui Chemicals, H-100) are kneaded with a biaxial kneader (manufactured by Toyo Seiki Co., Ltd., Labo Plast Mill). Compound pellets were obtained.

This compound was injection-molded under the conditions of an injection temperature of 170 ° C. and a mold temperature of 60 ° C. using an injection molding machine (manufactured by Nissei Plastic Industry Co., Ltd., EX500-5E). A temperature test piece was obtained.
Using this test piece, tensile strength, elongation at break, and Charpy impact strength were measured. Further, this test piece was left in a constant temperature bath at a temperature of 65 ° C. and a humidity of 85% for 1,000 hours, and the same mechanical strength as described above was measured.
Further, the deflection temperature under load was measured under a 0.45 MPa load condition.
The results are summarized in Table 2.

(Example 2)
Instead of using 60 parts by weight of β-hydroxybutyric acid in Example 1, biomass particles (2) were obtained in the same manner as in Example 1 except that 20 parts by weight of 1,4-butanediol and 30 parts by weight of succinic acid were used. It was. The biomass particles (2) were evaluated in the same manner as in Example 1.
Thereafter, the same molding as in Example 1 was performed, and the molded body was evaluated in the same manner as in Example 1. The results are summarized in Tables 1 and 2.

(Example 3)
In Example 1, biomass particles were obtained in the same manner as in Example 1 except that 22 parts by weight of 1,9-nonanediol and 34 parts by weight of 1,10-decamethylenedicarboxylic acid were used instead of 60 parts by weight of β-hydroxybutyric acid. (3) was obtained. The biomass particles (3) were evaluated in the same manner as in Example 1.
Thereafter, the same molding as in Example 1 was performed, and the molded body was evaluated in the same manner as in Example 1. The results are summarized in Tables 1 and 2.

Example 4
Instead of using 10 parts by weight of the obtained biomass particles (1) and 90 parts by weight of a polylactic acid resin (manufactured by Mitsui Chemicals, H-100) in Example 1, 40 parts by weight of the obtained biomass particles (1) A compound pellet was obtained in the same manner as in Example 1 except that 60 parts by weight of a polylactic acid resin (manufactured by Mitsui Chemicals, H-100) was used, and the same molding and evaluation as in Example 1 were performed. The results are shown in Tables 1 and 2.

(Example 5)
In Example 1, instead of using 10 parts by weight of the obtained biomass particles (1) and 90 parts by weight of a polylactic acid resin (manufactured by Mitsui Chemicals, H-100), 5 parts by weight of the obtained biomass particles (1) And the compound pellet was obtained like Example 1 except using 95 weight part of polylactic acid resin (the Mitsui Chemicals make, H-100), and shaping | molding and evaluation similar to Example 1 were implemented. The results are shown in Tables 1 and 2.

(Example 6)
In Example 1, dodecylbenzenesulfonic acid was changed to 2 parts by weight to obtain biomass particles (4) having an average particle size of 9 μm. Evaluation similar to Example 1 was implemented using this biomass particle | grain (4). The results are summarized in Tables 1 and 2.

(Example 7)
In Example 1, dodecylbenzenesulfonic acid was changed to 0.2 parts by weight to obtain biomass particles (5) having an average particle diameter of 500 nm. Evaluation similar to Example 1 was implemented using this biomass particle | grains (5). The results are summarized in Tables 1 and 2.

(Example 8)
In a 1 L three-necked flask, 5 parts by weight of dodecylbenzenesulfonic acid was mixed with 1,000 parts by weight of ion-exchanged water and dissolved. A solution prepared by heating 100 parts by weight of lactic acid to 110 ° C. was added thereto, emulsified with a homogenizer (manufactured by IKA, Ultratax) for 10 minutes, and further emulsified in an ultrasonic bath for 10 minutes, and then the emulsion was stirred. While maintaining at 70 ° C. in the flask, the mixture was further maintained for 20 hours.
Thereby, biomass particles (6) having an average particle diameter of 2 μm were obtained.
10 parts by weight of the obtained biomass particles (6) and 90 parts by weight of a polylactic acid resin (manufactured by Mitsui Chemicals, H-100) are kneaded with a biaxial kneader (manufactured by Toyo Seiki Co., Ltd., Labo Plast Mill). Compound pellets were obtained.

Using this compound, an ISO 3167 multipurpose test piece 1A type and a deflection temperature test piece under load are obtained with an injection molding machine (EX500-5E, manufactured by Nissei Plastic Industry Co., Ltd.) under conditions of an injection temperature of 170 ° C. and a mold temperature of 60 ° C. It was. Using this test piece, tensile strength, elongation at break, and Charpy impact strength were measured. Further, this test piece was left in a constant temperature bath at a temperature of 65 ° C. and a humidity of 85% for 1,000 hours, and the same mechanical strength as described above was measured.
Further, the deflection temperature under load was measured under a 0.45 MPa load condition.
The results are summarized in Tables 1 and 2.

(Comparative Example 1)
Multi-purpose of ISO 3167 with 100 parts by weight of polylactic acid resin (Mitsui Chemicals Co., Ltd., H-100) on an injection molding machine (Nissei Plastics Co., Ltd., EX500-5E) under conditions of an injection temperature of 170 ° C. and a mold temperature of 60 ° C. A test piece 1A type and a deflection temperature test piece under load were obtained. Using this test piece, tensile strength, elongation at break, and Charpy impact strength were measured. Further, this test piece was left in a constant temperature bath at a temperature of 65 ° C. and a humidity of 85% for 1,000 hours, and the mechanical strength was measured in the same manner as described above.
Further, the deflection temperature under load was measured under a 0.45 MPa load condition.
The results are summarized in Tables 1 and 2.

(Comparative Example 2)
80 parts by weight of polylactic acid resin (Mitsui Chemicals, H-100) and 20 parts by weight of glass fiber (Asahi Fiber Glass, chopped strand) are kneaded in a twin-screw kneader (Toyo Seiki, Lab Plast Mill). And compound pellets were obtained.
Using this compound, an ISO 3167 multipurpose test piece 1A type and a deflection temperature test piece under load are obtained with an injection molding machine (EX500-5E, manufactured by Nissei Plastic Industry Co., Ltd.) under conditions of an injection temperature of 170 ° C. and a mold temperature of 60 ° C. It was. Using this test piece, tensile strength, elongation at break, and Charpy impact strength were measured. Further, this test piece was left in a constant temperature bath at a temperature of 65 ° C. and a humidity of 85% for 1000 hours, and the same mechanical strength as described above was measured.
Further, the deflection temperature under load was measured under a 0.45 MPa load condition.
The results are summarized in Tables 1 and 2.

  As described above, the biomass particle of the present invention is a material having a plant-derived polymer material as a main component, extremely low environmental load, high mechanical strength, high heat resistance, and extremely excellent as a molding material. In addition, the molded body made of biomass particles has high mechanical strength and heat resistance, and is excellent in durability at high temperature and high humidity. For example, it is suitable for housings of home appliances, office equipment, various parts, and the like.

Furthermore, as described above, the polylactic acid molded body compounded with the biomass particles of the present invention shown in Examples 1 to 8 has high impact strength and heat resistance, and maintains mechanical strength under high temperature and high humidity. Is also excellent. On the other hand, since the polylactic acid molded body to which the biomass particles of the present invention are not added has low impact strength and heat resistance and causes hydrolysis, mechanical strength deterioration under high temperature and high humidity is severe.
The biomass particles of the present invention act as a crystal nucleating agent, are particles that are extremely excellent as impact resistance and heat resistance improvers for polylactic acid molded products, and obtain molded products that are also excellent in recyclability and biodegradability disposal. be able to.

Claims (2)

Biomass particles obtained by polycondensation of a polycondensable monomer containing at least lactic acid in an aqueous medium,
The biomass particles, wherein an average particle size of the biomass particles is 10 μm or less. An average particle size of 10 μm or less, comprising: a step of dispersing an oil phase containing a polycondensable monomer containing at least lactic acid in an aqueous medium; and a step of polycondensing the polycondensable monomer. A method for producing biomass particles.