JP2005060600A - Biodegradable resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a biodegradable resin composition composed of a polylactic acid and a nano sheet layer titanic acid, superior in mechanical strengths, moldability, dimensional stability and durability. <P>SOLUTION: This biodegradable resin composition is composed of a polylactic acid and a nano sheet layer titanic acid. The nano sheet layer titanic acid is made by a method comprising steps of (1) treating a layer titanic acid salt represented by general formula (1): A<SB>x</SB>My▵<SB>z</SB>Ti<SB>2-(y+z)</SB>O<SB>4</SB>(wherein A and M are each different metals of 1-3 valency, ▵ is a defect site of Ti, x is a positive real number of 0<x<1.0, and y and z are each positive real number of 0<y+z<1.0) with acid or hot water so that A and/or M ion are substituted by hydrogen and/or hydronium ion and (2) swelling or peeling between layers by using a basic compound having an inter layer swelling effect. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a biodegradable resin composition comprising polylactic acid and nanosheet-formed layered titanic acid and having excellent mechanical strength, moldability, dimensional stability and durability.

  In recent years, research on biodegradable resins as environmentally friendly polymers has been actively conducted. In particular, not only from the viewpoint of biodegradation, but also polylactic acid made from plants that enable carbon neutrality has attracted a great deal of attention because of its high cost and physical properties. However, the molded product has a problem that heat resistance, rigidity, impact resistance and the like are inferior, and has not yet been fully developed. As a solution to such drawbacks, a composition in which a layered silicate nanosheet treated with a swelling agent such as an ammonium salt or a phosphonium salt is uniformly dispersed in polylactic acid, and a film or function obtained therefrom Technology relating to a conductive material has been disclosed, and it has been shown that by combining polylactic acid and layered silicate, excellent heat resistance and rigidity, or gas barrier properties can be obtained while suppressing specific gravity (for example, (See Patent Documents 1 and 2).

However, in this method, the better the dispersion of the layered silicate nanosheets in polylactic acid, the lower the molecular weight during kneading and the lower the melt viscosity. The decrease in melt viscosity deteriorates the dimensional stability because it deteriorates the molding processability of, for example, a film and further increases the coefficient of thermal expansion at high temperatures.
JP 2003-82212 A JP 2003-73538 A

  An object of the present invention is to provide a biodegradable resin composition comprising polylactic acid and nanosheeted layered titanic acid, which is excellent in mechanical strength, moldability, dimensional stability and durability. There is to do.

  As a result of diligent research, the present inventor has found that a biodegradable resin composition comprising polylactic acid and nanosheeted layered titanic acid is excellent in mechanical strength, moldability, dimensional stability and durability. It came to be completed.

  That is, this invention relates to the biodegradable resin composition of the following 1-7, nanosheeted layered titanic acid, and its manufacturing method.

  1. A biodegradable resin composition comprising polylactic acid and nanosheeted layered titanic acid.

  2. A biodegradable resin composition comprising 100 parts by weight of polylactic acid and 0.5 to 100 parts by weight of nanosheeted layered titanic acid.

3. Nanosheeted layered titanic acid has the general formula
A _x My □ _z Ti _{2- (y + z)} O ₄ (1)
[Wherein, A and M represent 1 to 3 valent metals different from each other, and □ represents a defect site of Ti. x is a positive real number satisfying 0 <x <1.0, and y and z are each 0 or a positive real number satisfying 0 <y + z <1.0],
(1) treating with acid or warm water and replacing A and / or M ions with hydrogen and / or hydronium ions;
(2) a step of causing a basic compound having an interlayer swelling action to act and swelling or peeling the interlayer;
The biodegradable resin composition according to 1 or 2 above, which is a nanosheet-formed layered titanic acid obtained by a production method comprising:

4). Nanosheeted layered titanic acid has the general formula
A _x My □ _z Ti _{2- (y + z)} O ₄ (1)
[Wherein, A and M represent 1 to 3 valent metals different from each other, and □ represents a defect site of Ti. x is a positive real number satisfying 0 <x <1.0, and y and z are each 0 or a positive real number satisfying 0 <y + z <1.0],
(1) treating with acid or warm water and replacing A and / or M ions with hydrogen and / or hydronium ions;
(2) a step of causing a basic compound having an interlayer swelling action to act and swelling or peeling the interlayer;
3. The biodegradable resin composition as described in 1 or 2 above, which is a nanosheet-formed layered titanic acid obtained by a production method in which one is performed in a single pot.

5). Nanosheeted layered titanic acid has the general formula
B _m C _n □ _{(y + z)} Ti _{2- (y + z)} O ₄ (2)
[In the formula, B represents a basic compound having an interlayer swelling action, C represents hydrogen and / or hydronium ion, and □ represents a defect site of Ti. m is a positive real number that satisfies 0.1 <m <0.7, n is a positive real number that satisfies 0.3 <n <0.9, and more preferably, n is 0.5 <n < It is a positive real number that satisfies 0.8. The sum of m and n corresponds to x in the general formula (1). The biodegradable resin composition according to any one of the above 1 to 4, which is a nanosheet-formed layered titanic acid represented by y and z each being 0 or a positive real number satisfying 0 <y + z <1.0] Stuff.

6). General formula
B _m C _n □ _{(y + z)} Ti _{2- (y + z)} O ₄ (2)
[In the formula, B represents a basic compound having an interlayer swelling action, C represents hydrogen and / or hydronium ion, and □ represents a defect site of Ti. m is a positive real number that satisfies 0.1 <m <0.7, n is a positive real number that satisfies 0.3 <n <0.9, and more preferably, n is 0.5 <n < It is a positive real number that satisfies 0.8. The sum of m and n corresponds to x in the general formula (1). And y and z are 0 or a positive real number satisfying 0 <y + z <1.0, respectively].

7). General formula
A _x My □ _z Ti _{2- (y + z)} O ₄ (1)
[Wherein, A and M represent 1 to 3 valent metals different from each other, and □ represents a defect site of Ti. x is a positive real number satisfying 0 <x <1.0, and y and z are each 0 or a positive real number satisfying 0 <y + z <1.0],
(1) treating with acid or warm water and replacing A and / or M ions with hydrogen and / or hydronium ions;
(2) a step of causing a basic compound having an interlayer swelling action to act and swelling or peeling the interlayer;
The manufacturing method of the nanosheet-ized layered titanic acid obtained by the manufacturing method which performs this in one pot.

  According to the present invention, an organically modified layered titanic acid can be uniformly dispersed in polylactic acid, and a biodegradable resin composition having good mechanical strength, moldability, dimensional stability, and durability is provided. Can do.

  The present invention is a biodegradable resin composition comprising polylactic acid and nanosheeted layered titanic acid.

  As polylactic acid used in the present invention, poly (L-lactic acid), poly (D-lactic acid), and a mixture or copolymer thereof can be used. Moreover, it does not restrict | limit especially as a manufacturing method of polylactic acid, A well-known method can be used. Examples thereof include direct polymerization of L-lactic acid and D-lactic acid and ring-opening polymerization of L-lactide, D-lactide, and meso-lactide, which are cyclic dimers of lactic acid.

The nanosheet layered titanic acid used in the present invention has a general formula
A _x My □ _z Ti _{2- (y + z)} O ₄ (1)
[Wherein, A and M represent 1 to 3 valent metals different from each other, and □ represents a defect site of Ti. x is a positive real number satisfying 0 <x <1.0, and y and z are 0 or a positive real number satisfying 0 <y + z <1.0, respectively]. Titanate ")
(1) treating with acid or warm water and replacing A and / or M ions with hydrogen and / or hydronium ions;
(2) a step of causing a basic compound having an interlayer swelling action to act and swelling or peeling the interlayer;
Is a layered titanic acid obtained by a production method (referred to as “nanosheetized layered titanic acid”).

  In the general formula (1), A is a metal having a valence of 1 to 3. Preferable A is potassium (K), rubidium (Rb) or cesium (Cs). M is a metal having a valence of 1 to 3 different from that of metal A. Preferred M is lithium (Li), magnesium (Mg), zinc (Zn), copper (Cu), iron (Fe), aluminum (Al), gallium (Ga), manganese (Mn) or nickel (Ni). good.

Specific examples of the general formula (1) include K _0.8 Li _0.266 Ti _1.733 O ₄ , Rb _0.75 Ti _1.75 Li _0.25 O ₄ , Cs _0.7 Ti _1.77 Li _0.23 O ₄ , Ce _0.7 Ti _1.825 □ _0.175 O ₄ , Ce _0.7 Ti _1.65 Mg _0.35 O ₄ , K _0.8 Ti _1.6 Mg _0.4 O ₄ , K _0.8 Ti _1.6 Ni _0.4 O ₄ , K _0.8 Ti _1.6 Zn _0.4 O ₄ , K _0.8 Ti _1.6 Cu _0.4 O ₄ , K _0.8 Ti _1.2 Fe _0.8 O ₄ K _0.8 Ti _1.2 Mn _0.8 O ₄ , K _0.76 Ti _1.73 Li _0.22 Mg _0.05 O ₄ , K _0.67 Ti _1.73 Al _0.07 Li _0.2 O _{4 and the} like.

Preferred layered titanates are K _0.8 Li _0.266 Ti _1.733 O ₄ and K _0.8 Ti _1.6 Mg _0.4 O ₄ .

  The shape of the nanosheet-formed layered titanic acid used in the present invention is plate-like or flaky (flaky), usually having an average thickness of 10 nm to 20 μm, preferably 20 nm to 10 μm, and an average major axis of usually 0.1 to 50 μm. The thickness is preferably 1 to 40 μm.

The preferred nanosheet layered titanic acid has the general formula
B _m C _n □ _{(y + z)} Ti _{2- (y + z)} O ₄ (2)
[In the formula, B represents a basic compound having an interlayer swelling action, C represents hydrogen and / or hydronium ion, and □ represents a defect site of Ti. m is a positive real number that satisfies 0.1 <m <0.7, n is a positive real number that satisfies 0.3 <n <0.9, and more preferably, n is 0.5 <n < It is a positive real number that satisfies 0.8. The sum of m and n corresponds to x in the general formula (1). Further, y and z are each 0 or a positive real number satisfying 0 <y + z <1.0]. In the general formula (2), when n is a positive real number satisfying 0.3 <n <0.9, the molecular weight reduction of the biodegradable resin composition after kneading can be further suppressed.

As a manufacturing method of the general formula (2), for example, the general formula
A _x My □ _z Ti _{2- (y + z)} O ₄ (1)
[Wherein, A and M represent 1 to 3 valent metals different from each other, and □ represents a defect site of Ti. x is a positive real number satisfying 0 <x <1.0, and y and z are each 0 or a positive real number satisfying 0 <y + z <1.0],
(1) treating with acid or warm water and replacing A and / or M ions with hydrogen and / or hydronium ions;
(2) a step of causing a basic compound having an interlayer swelling action to act and swelling or peeling the interlayer;
It can obtain by the manufacturing method containing these.

The layered titanate represented by the general formula (1) can be produced, for example, by the method disclosed in Japanese Patent No. 3062497. Specifically, the oxides of metals A, M, and Ti or the raw material compounds that become the oxides by heating may be pulverized and mixed as necessary, and then heated and fired in the presence or mixing of fluxes. Examples of the flux include alkali metal halides and sulfates, alkaline earth metal halides and sulfates, and the like. The flux may be used so that the weight ratio of the flux / raw material compound is 0.1 to 2.0. Heating and baking are performed at a temperature of 700 to 1200 ° C. As another production method, according to the method disclosed in Japanese Patent No. 2979132, cesium carbonate and titanium dioxide are mixed at a molar ratio of 1: 5.3, and calcined at 800 ° C. According to a method for obtaining orthorhombic cesium titanate (Cs _x Ti _{2-x / 4} O ₄ , x = 0.70) as a salt compound, according to a method disclosed in International Publication No. WO99 / 11574, Lithium and titanium dioxide are mixed at K / Li / Ti = 3/1 / 6.5 (molar ratio), ground, and fired at 800 ° C. _{Examples include a} method of obtaining _0.8 Li _0.27 Ti _1.73 O ₄ .

  In step (1) and step (2), step (1) is followed by step (2) (production method 1), and step (1) and step (2) are carried out in one pot (production method 2). There is.

  As a method of performing the step (2) after the step (1), first, the layered titanate represented by the general formula (1) is subjected to acid treatment or hot water treatment [step (1)].

  In the case of acid treatment, for example, an acid may be added to the aqueous dispersion of the layered titanate represented by the general formula (1), preferably with stirring. The amount of the layered titanate in the aqueous dispersion is not particularly limited and may be appropriately selected in consideration of workability and the like. As the acid, for example, inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid and boric acid can be preferably used, but organic acids may also be used. The amount of the acid used can be appropriately selected from a wide range depending on the substitution rate of the A and / or M ions in the general formula (1) of the layered titanate with hydrogen and / or hydronium ions. About 10 to 2000 equivalent% of the ion exchange capacity of titanate may be used. The acid treatment may be performed by a single operation, or may be performed repeatedly by decreasing the acid concentration or reducing the amount of acid used. When the acid treatment is repeated, the substitution rate can be changed easily. Thereby, the substitution rate can be changed if the number of times is repeated even with a small amount of acid. The reaction is usually carried out at 60 to 90 ° C. for about 30 minutes to 24 hours.

  In the case of warm water treatment, for example, the layered titanate may be dispersed in warm water of usually 40 ° C. or higher, preferably 60 ° C. or higher, and stirred. The hot water treatment is usually completed in 1 to 10 hours, preferably 2 to 5 hours. The hot water treatment may be repeated.

  By the acid treatment or hot water treatment, layered titanic acid in which A and / or M ions in the layered titanate are titaniumized with hydrogen and / or hydronium ions can be obtained. In the obtained layered titanic acid, the substitution rate of the metal represented by A and M with hydrogen and / or hydronium ions can be measured according to a known method. For example, Li can be quantified by flame analysis after dissolving a sample in sulfuric acid containing ammonium sulfate. At the same time, K, Ti, Mg, Rb, Cs, Zn, Al, Fe, Mn, Cu, Ni, Ga, etc. can be quantified by fluorescent X-ray analysis. Therefore, the substitution rate can be calculated by quantifying the amount of metal before and after the acid treatment or the hot water treatment.

  Next, a basic compound having an interlayer swelling action is allowed to act on the layered titanic acid obtained above to swell or peel the interlayer [step (2)].

  Examples of the basic compound having an interlayer swelling action include primary to tertiary amines and salts thereof, quaternary ammonium salts, phosphonium salts, amino acids and salts thereof, and the like. Examples of the primary amine include methylamine, ethylamine, n-propylamine, butylamine, pentylamine, hexylamine, octylamine, dodecylamine, stearylamine and the like. Examples of the secondary amine include diethylamine, dipentylamine, dioctylamine, dibenzylamine and the like. Examples of the tertiary amine include triethylamine and trioctylamine. Alkylamines such as 2-ethylhexylamine or salts thereof, and ethanolamine, diethanolamine, triethanolamine, isopropanolamine, diisopropanolamine, triisopropanolamine, N, N-dimethylethanolamine, 2-amino-2-methyl- Alkanolamines such as 1-propanol or salts thereof, quaternary ammonium salts such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, dodecyltrimethylammonium salt, cetyl Trimethylammonium salt, stearyltrimethylammonium salt, benzyltrimethylammonium salt, benzyltributylammonium salt, trimethylphenol Quaternary ammonium salts such as nyl ammonium salt, dimethyl distearyl ammonium salt, dimethyl didecyl ammonium salt, dimethyl stearyl benzyl ammonium salt, dodecyl bis (2-hydroxyethyl) methyl ammonium salt, trioctyl methyl ammonium salt, 12-aminododecanoic acid And amino acids such as aminocaproic acid or salts thereof, 3-methoxypropylamine, 3-ethoxypropylamine, polyethyleneimine or salts thereof, and polydiallyldimethylammonium chloride. Furthermore, organic phosphonium salts such as tetrabutylphosphonium salt, hexadecyltributylphosphonium salt, dodecyltributylphosphonium salt, and dodecyltriphenylphosphonium salt can also be used. These basic compounds may be used singly or as a mixture of several types depending on the purpose.

  In order to make a basic compound having an interlayer swelling action act, a basic compound or a basic compound is added to an aqueous medium under stirring in a suspension in which layered titanic acid after acid treatment or hot water treatment is dispersed in an aqueous medium. What is diluted with is sufficient. Alternatively, the layered titanic acid or a suspension thereof may be added to an aqueous solution of the basic compound with stirring.

  The aqueous medium or aqueous solution means water, a solvent soluble in water, a mixed solvent of water and a solvent soluble in water, or a solution thereof.

  Examples of the water-soluble solvent include alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol, ketones such as acetone, ethers such as tetrahydrofuran and dioxane, nitriles such as acetonitrile, ethyl acetate, propylene carbonate and the like. Of these esters.

  In consideration of substitution with a basic compound having a swelling action while hydrogen and / or hydronium ions remain between layers, the basic compound is added in an amount of ions of the layered titanate represented by the formula (1). It is good to set it as 1-200 equivalent% of an exchange capacity, Preferably it is 5-100 equivalent%. Here, the ion exchange capacity is a value represented by mx + ny, where m is the valence of A in the general formula (1) of the layered titanate and n is the valence of M.

  The reaction is usually carried out at 60 to 90 ° C. for about 30 minutes to 24 hours.

  By the above (Manufacturing method 1), the nanosheet-ized layered titanic acid used in the present invention can be obtained.

  As a method of performing the steps (1) and (2) in one pot, an acid and a basic compound having an interlayer swelling action are allowed to act on the layered titanate represented by the general formula (1) in one pot. In the present invention, “one pot” means that the addition of the acid and the basic compound is continuously performed without interposing other steps such as a washing step, or the acid and the basic compound are added simultaneously. For example, to a suspension in which the layered titanate is dispersed in an aqueous medium, an acid or an acid diluted with an aqueous medium is added with stirring, and then a basic compound having an interlayer swelling action or an interlayer swelling action is added. What is necessary is just to add what diluted basic compound with an aqueous medium. In addition, after stirring, a suspension in which the layered titanate is dispersed in an aqueous medium is added with stirring, a basic compound having an interlayer swelling action or a basic compound having an interlayer swelling action diluted with an aqueous medium. Subsequently, an acid or an acid diluted with an aqueous medium may be added. Further, a mixture of a basic compound having an interlayer swelling action and an acid, or a mixture obtained by diluting it with an aqueous medium may be added to the suspension. Further, the order of addition may be reversed, and a layered titanate or a layered titanate dispersed in an aqueous medium may be added to the mixed solution of the acid and the basic compound. Here, the aqueous medium means water, a solvent soluble in water, or a mixed solvent of water and a solvent soluble in water.

  Examples of the water-soluble solvent include alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol, ketones such as acetone, ethers such as tetrahydrofuran and dioxane, nitriles such as acetonitrile, ethyl acetate, propylene carbonate and the like. Of these esters.

  As the acid, for example, inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid and boric acid can be preferably used, but organic acids may also be used.

  The amount of the acid used can be appropriately selected from a wide range depending on the substitution rate of the A and / or M ions in the general formula (1) of the layered titanate with hydrogen and / or hydronium ions. 5 to 250 equivalent%, preferably 10 to 200 equivalent%, of the ion exchange capacity of titanate may be used. If it exceeds 200 equivalent%, the A and / or M ions of the titanate are merely replaced with hydrogen ions and / or hydronium ions, and interlayer swelling is less likely to occur. Here, the ion exchange capacity is a value represented by mx + ny, where m is the valence of A in the general formula (1) of the layered titanate and n is the valence of M.

  Examples of the basic compound having an interlayer swelling action include primary to tertiary amines and salts thereof, quaternary ammonium salts, phosphonium salts, amino acids and salts thereof, and the like. Examples of the primary amine include methylamine, ethylamine, n-propylamine, butylamine, pentylamine, hexylamine, octylamine, dodecylamine, stearylamine and the like. Examples of the secondary amine include diethylamine, dipentylamine, dioctylamine, dibenzylamine and the like. Examples of the tertiary amine include triethylamine and trioctylamine. Alkylamines such as 2-ethylhexylamine or salts thereof, and ethanolamine, diethanolamine, triethanolamine, isopropanolamine, diisopropanolamine, triisopropanolamine, N, N-dimethylethanolamine, 2-amino-2-methyl- Alkanolamines such as 1-propanol or salts thereof, quaternary ammonium salts such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, dodecyltrimethylammonium salt, cetyl Trimethylammonium salt, stearyltrimethylammonium salt, benzyltrimethylammonium salt, benzyltributylammonium salt, trimethylphenol Quaternary ammonium salts such as nyl ammonium salt, dimethyl distearyl ammonium salt, dimethyl didecyl ammonium salt, dimethyl stearyl benzyl ammonium salt, dodecyl bis (2-hydroxyethyl) methyl ammonium salt, trioctyl methyl ammonium salt, 12-aminododecanoic acid And amino acids such as aminocaproic acid or salts thereof, 3-methoxypropylamine, 3-ethoxypropylamine, polyethyleneimine or salts thereof, and polydiallyldimethylammonium chloride. Furthermore, organic phosphonium salts such as tetrabutylphosphonium salt, hexadecyltributylphosphonium salt, dodecyltributylphosphonium salt, and dodecyltriphenylphosphonium salt can also be used. These basic compounds may be used singly or as a mixture of several types depending on the purpose.

  The amount of the basic compound having an interlayer swelling action may be 5 to 100 equivalent%, preferably 10 to 100 equivalent%, of the ion exchange capacity of the layered titanate. If it is less than 5 equivalent%, the swelling hardly progresses, and if it exceeds 100 equivalent%, the effect on swelling is small, which is not only economically disadvantageous, but also may interfere with filtration and the like.

  When a basic compound and an acid having an interlayer swelling action are acted on a layered titanate in one pot, overheating is not a necessary condition, but a basic compound having an interlayer swelling action is required for promoting the reaction. It may be heated to dissolve it.

  The reaction is usually carried out at 60 to 90 ° C. for about 30 minutes to 24 hours.

  By the above (Manufacturing method 2), the nanosheet-ized layered titanic acid used in the present invention can be obtained.

  As a preferable production method, a production method shown in Production Method 2 in which an acid and a basic compound having an interlayer swelling action are allowed to act in one pot is preferable. Since it can react in one pot, the production time can be shortened, and nanosheet-formed layered titanic acid can be produced economically. Further, the nanosheeted layered titanic acid obtained by the production method 2 is less clear than the nanosheeted layered titanic acid obtained by the production method 1, but the molecular weight of the biodegradable resin composition after kneading is reduced. It can be suppressed more.

  Depending on the amount of acid used or the amount of basic compound having an interlayer swelling action, not all of the A and / or M ions of the layered titanate may be substituted. In that case, the nanosheeted layered titanic acid swelled with basic compounds remains with some of the A and / or M ions remaining. The layered titanic acid referred to here includes such layered titanic acid in which A and / or M ions remain.

  In the biodegradable resin composition of the present invention, the blending amount of the nanosheet-formed layered titanic acid is not particularly limited and may be appropriately selected, but is usually 0.5 to 100 parts by weight, preferably 100 parts by weight of polylactic acid, What is necessary is just to be 1-30 weight part. If the amount is less than 0.5 parts by weight, the reinforcing effect cannot be expected, while if it exceeds 100 parts by weight, molding becomes difficult.

  The biodegradable resin composition of the present invention can be copolymerized or mixed with other biodegradable resins, if necessary, within a range that does not impair the characteristics. Other biodegradable resins include, for example, polyethylene succinate, aliphatic polyesters typified by polybutylene succinate, polyglycolic acid, polyhydroxycarboxylic acids typified by poly-3-hydroxybutyric acid, poly ε-caprolactam, etc. Other examples include poly ω-hydroxyalkanoates, polyester amides, polyester carbonates and polysaccharides.

  The biodegradable resin composition of this invention can mix | blend 1 type (s) or 2 or more types of the various organic compound or inorganic compound conventionally used as a resin additive in the range which does not impair the preferable characteristic. Specific examples thereof include, for example, inorganic fillers of various shapes (particulate, fibrous, flake shaped), pigments, antioxidants, flame retardants, anti-drip agents, ultraviolet absorbers, light stabilizers, light-shielding agents, Examples thereof include metal deactivators, anti-aging agents, lubricants, plasticizers, impact strength improvers, and compatibilizers.

  The biodegradable resin composition of the present invention can be produced by mixing or kneading a predetermined amount of nanosheeted layered titanic acid and, if necessary, a resin additive with polylactic acid according to known means. For example, powder, beads, flakes or pellets are mixed with a mixer or tumbler as necessary, and then a single-screw extruder, twin-screw extruder, etc., Banbury mixer, kneader, mixing roll, etc. The biodegradable resin composition of the present invention can be obtained by mixing and kneading using a kneader. The resin composition thus obtained can be pelletized with a pulverizer or pelletizer, and processed into any shape such as a film, tube, sheet, various molded articles, etc., according to known molding means such as injection molding or extrusion molding. it can. In addition, a masterbatch containing nanosheet layered layered titanic acid at a high concentration is prepared and used by diluting or mixing with the same or different resin as the masterbatch resin at the stage of molding by injection molding or extrusion molding. be able to.

  The biodegradable resin composition of the present invention can be processed into various molded products and used by methods such as injection molding and extrusion molding. As molded products, it can be used as injection molded products, extrusion molded products, blow molded products, films, fibers, sheets, etc., and as films, various films such as unstretched, uniaxially stretched and biaxially stretched. As the fiber, it can be used as various fibers such as undrawn yarn and drawn yarn. Or these can be utilized for various uses, such as an electrical / electronic component, a building member, a motor vehicle part, and daily necessities.

  The biodegradable resin composition of the present invention can be a foam. When foaming the biodegradable resin composition of the present invention, a known foaming method using a decomposable foaming agent can be employed. As the decomposable foaming agent, any of known organic decomposable foaming agents and inorganic decomposable foaming agents can be used. Examples of the organic decomposable blowing agent include azo compounds such as azodicarbonamide, azoisobutyronitrile, diazoaminobenzene, azodicarboxylate barium, hydrazodiazocarbonamide, p-toluenesulfonyl hydrazide, 4,4. Sulfonyl hydrazide compounds such as' -oxybis (benzenesulfonylhydrazide), nitroso compounds such as N, N'-dinitrosopentamethylenetetramine, N, N'-dinitroso-N, N'-dimethylterephthalamide, 5-phenyltetrazole, Examples include heterocyclic compounds such as 4-aminourazole. Examples of the inorganic decomposable foaming agent include calcium carbonate, sodium bicarbonate, sodium carbonate, calcium oxide, sodium oxide, magnesium oxide and the like. One type of decomposable foaming agent can be used alone, or two or more types can be used in combination. The compounding amount of the decomposable foaming agent is not particularly limited, and it is a wide range depending on various conditions such as the type of resin, the amount of layered titanic acid, the type of decomposable foaming agent itself, the foaming conditions, and the use of the resulting foam. However, it is usually 1-30 parts by weight, preferably 2-15 parts by weight, based on 100 parts by weight of the resin composition of the present invention.

  The organic decomposable foaming agent may be subjected to a surface treatment. Known surface treatment agents can be used, such as silane coupling agents (methyltrimethoxysilane, γ-aminopropyltriethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, N-phenylaminomethyltrimethoxysilane, vinylmethyldiethoxysilane, etc.), aluminum coupling agents (aluminum isopropylate, aluminum ethylate, aluminum (ethyl acetoacetylate), ethyl acetoacetate aluminum diisopropylate, etc.), titanate Coupling agents (isopropyl triisostearoyl titanate, isopropyl tris (dioctyl pyrophosphate) titanate, tetraoctyl bis (ditridecyl phosphite) titanate, bis (dioctyl Pyrophosphates), oxyacetate titanates, etc.), liquid or solid oils (soybean oil, coconut oil, linseed oil, cottonseed oil, rapeseed oil, drill oil, pine oil, rosin, castor oil, beef tallow, squalane, lanolin , Plant or animal natural fats and oils such as hydrogenated oil and their refined products), hydrocarbons (aliphatic hydrocarbons having 20 to 48 carbon atoms and derivatives thereof, and aromatic hydrocarbons having 8 to 19 carbon atoms) And derivatives thereof (for example, dialkyl phthalates such as dioctyl phthalate, higher alcohol phthalates such as nonyl alcohol phthalate), paraffinic, naphthenic or aromatic process oils, palmitic acid, stearic acid, oleic acid, behemic acid, etc. Fats and oils such as fatty acids and their salts or derivatives) That.

  A decomposition accelerator can be blended within a range that does not impair the physical properties of the obtained foam. Known decomposition accelerators can be used, for example, metal oxides such as zinc oxide and lead oxide, metal carbonates such as zinc carbonate, lead carbonate and potassium carbonate, metal chlorides such as zinc chloride and potassium chloride, Examples thereof include metal acetates such as zinc acetate, zinc oleate, zinc stearylate, sodium benzenesulfinate, zinc 2-ethylhexoate, urea and the like. A decomposition accelerator can be used individually by 1 type, or can use 2 or more types together. When the decomposition accelerator is blended, the blending amount is not particularly limited, but is usually 5 to 100 parts by weight, preferably 10 to 50 parts by weight, based on 100 parts by weight of the decomposable foaming agent.

  A foam nucleating agent can be blended within a range that does not impair the physical properties of the obtained foam. Known foam nucleating agents can be used, and examples thereof include talc, silica, calcium carbonate, clay, zeolite, kaolin, bentonite, aluminum oxide, magnesium carbonate and the like. A nucleating agent can be used individually by 1 type, or may use 2 or more types together. The amount of the foam nucleating agent is not particularly limited, and the type of resin, the type and amount of nanosheeted layered titanic acid, the type of foaming nucleating agent itself, the type and amount of decomposition foaming agent, and the foaming conditions to be obtained. What is necessary is just to select suitably from a wide range according to various conditions, such as a physical property and a use of a foam, Usually, 0.1-50 weight part with respect to 100 weight part of this invention resin composition, Preferably 0.5- It may be 1 part by weight.

  More specifically, as a known foaming method using a decomposable foaming agent, more specifically, (1) a resin, a nanosheeted layered titanic acid and a decomposable foaming agent are kneaded at a temperature at which the decomposable foaming agent is not decomposed. A molded product obtained by extrusion molding, calender roll molding, press molding, etc., and then heating to decompose the decomposable foaming agent to generate gas and obtain a foam, (2) resin, Nanosheeted layered titanic acid and decomposable foaming agent are kneaded at a temperature at which the decomposable foaming agent is not decomposed, and the resulting kneaded product is pulp paper, aluminum hydroxide paper, cloth, gypsum board, fiber base board, perlite board, etc. Using a coating device such as a knife coater, roll coater, or spray on the substrate, or a printing device such as silk screen printing or rotary screen printing, the film thickness after drying is 0.05 to 0.50 mm. 30 seconds at a temperature at which the decomposable foaming agent does not decompose (usually 80 to 150 ° C.) using a drying furnace such as an electric heating type hot air furnace, an LPG combustion type hot air furnace, or an oil combustion type hot air furnace. Drying for 5 minutes, then raising the temperature to the decomposition temperature of the decomposable foaming agent, decomposing the decomposable foaming agent to obtain a foam, (3) resin, nanosheeted layered titanic acid and decomposable foaming agent Examples thereof include a method of mixing, performing extrusion molding, injection molding, and press molding at a temperature at which resin melting and decomposition of the decomposable foaming agent occur to obtain a foam having a predetermined shape. In any method, foaming (= decomposition of the decomposable foaming agent) is usually performed at a temperature of 180 to 230 ° C. and is usually completed in about 30 seconds to 3 minutes.

  The foam thus obtained can be used for the same applications as the molded body of the biodegradable resin composition of the present invention.

  EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples. In the following description, “%” and “parts” mean weight basis unless otherwise specified.

<Example 1> (Synthesis of layered titanate) A raw material obtained by pulverizing and mixing 27.64 g of potassium carbonate, 4.91 g of lithium carbonate, 69.23 g of titanium dioxide and 74.56 g of potassium chloride at 1050 ° C. for 4 hours. Baked. The baked sample was immersed in 10 kg pure, stirred for 20 hours, separated, washed with water, and dried at 110 ° C. The obtained white powder was layered titanate K _0.80 Li _0.266 Ti _1.733 O ₄ and had an average major axis of 28 μm and an average thickness of 2.5 μm.

  (Synthesis of Organized Layered Titanate) 65 g of this layered titanate was dispersed in 4 kg of deionized water, and 63 g of dodecylmethylbis (hydroxyethyl) ammonium chloride was added and dissolved. Further, 28 g of 35% hydrochloric acid was added and reacted at 80 ° C. for 1 hour, and then separated by suction filtration. After thoroughly washing with hot water, it was dried in air at 40 ° C. Furthermore, it was dried at 160 ° C. under reduced pressure for 12 hours to obtain an organically layered titanic acid in which 67 equivalent% of hydrogen ions or hydronium ions remained in the potassium / and lithium ion part of the titanate and the layers were swollen. It was. The obtained organically modified layered titanic acid had an average major axis of 24 μm and an average thickness of 4.1 μm.

  (Production and evaluation of biodegradable resin composition) The above-mentioned organic layered titanic acid was added to polylactic acid (Tm = 169 ° C., Tg = 60 ° C.) so as to have an ash content of 5%. Kneading with Seiki Co., Ltd. The kneading conditions were 200 ° C., 60 rpm, and 5 minutes. The taken out resin composition was pulverized, and a test piece compliant with JIS was molded with an injection molding machine (manufactured by Sumitomo Heavy Industries, trade name: Minimat M26) at a cylinder temperature of 200 ° C. and a mold temperature of 25 ° C. Using this test piece, the flexural modulus (JIS K7203) was determined, and GPC (manufactured by Waters) was used for molecular weight measurement. The melt viscosity was evaluated by comparison with a flow rate obtained with a low load extrusion type capillary rheometer (manufactured by Shimadzu Corporation, trade name: Shimadzu Flow Tester CFT-500D / 100D). Furthermore, TMA / SS6000 (manufactured by Seiko Instruments Inc.) was used for measuring the thermal expansion coefficient, and values of 150 ° C. to 160 ° C. were compared as thermal expansion coefficients near the melting point. The durability was evaluated by actively hydrolyzing the test piece under the conditions of 60 ° C. and 90% humidity for 3 days, and then comparing the bending elastic modulus (JIS K7203) of the test piece. The results are shown in Table 1.

Example 2 (Synthesis of Layered _Titanate ) Layered titanate K _0.80 Li _0.266 Ti _1.733 O ₄ was synthesized under the same conditions as in Example 1.

  (Synthesis of Organized Layered Titanate) 130 g of this layered titanate was dispersed in 8 kg of deionized water, and 134 g of stearyltrimethylammonium chloride was added and dissolved. Further, 56 g of 35% hydrochloric acid was added and reacted at 80 ° C. for 1 hour, and then separated by suction filtration. After thoroughly washing with a mixed solution of water and methanol, it was dried at 40 ° C. in air. Furthermore, it was dried at 160 ° C. under reduced pressure for 12 hours to obtain an organically layered titanic acid in which 65 equivalent% of hydrogen ions or hydronium ions remained in the potassium / and lithium ion part of the titanate and the layers were swollen. It was. The obtained organically modified layered titanic acid had an average major axis of 25 μm and an average thickness of 4.5 μm.

  (Production and Evaluation of Biodegradable Resin Composition) Resin test pieces were produced in the same manner as in Example 1, and each test was performed. The results are shown in Table 1.

<Example 3>
(Synthesis of Layered _Titanate ) Layered titanate K _0.80 Li _0.266 Ti _1.733 O ₄ was synthesized under the same conditions as in Example 1.

  (Synthesis of Organized Layered Titanic Acid) 26 g of this layered titanate was dispersed in 1600 g of deionized water, and 45.2 g of dimethyl distearyl ammonium chloride was added and dissolved. Further, 5.6 g of 35% hydrochloric acid was added and reacted at 80 ° C. for 1 hour, and then separated by suction filtration. After thoroughly washing with a mixed solution of water and methanol, it was dried at 40 ° C. in air. Furthermore, it was dried at 160 ° C. under reduced pressure for 12 hours to obtain an organically layered titanic acid in which 77 equivalent% of hydrogen ions or hydronium ions remained with respect to the potassium / and lithium ion part of the titanate and the layers were swollen. It was. The obtained organically modified layered titanic acid had an average major axis of 24 μm and an average thickness of 4.6 μm.

  (Production and Evaluation of Biodegradable Resin Composition) Resin test pieces were produced in the same manner as in Example 1, and each test was performed. The results are shown in Table 1.

<Example 4>
(Synthesis of Layered _Titanate ) Layered titanate K _0.80 Li _0.266 Ti _1.733 O ₄ was synthesized under the same conditions as in Example 1.

  (Synthesis of Organized Layered Titanic Acid) After diluting 8.0 g of 35% hydrochloric acid with 800 g of deionized water, 21 g of octadecylamine was added and dissolved. Further, 13 g of the layered titanate was added and reacted at 80 ° C. for 1 hour, and then separated by suction filtration. After thoroughly washing with a mixed solution of water and methanol, it was dried at 40 ° C. in air. Furthermore, it was dried at 160 ° C. under reduced pressure for 12 hours to obtain an organized layered titanic acid in which 57 equivalent% of hydrogen ions or hydronium ions remained in the potassium / and lithium ion part of the titanate and the layers were swollen. It was. The obtained organically modified layered titanic acid had an average major axis of 23 μm and an average thickness of 4.8 μm.

  (Production and Evaluation of Biodegradable Resin Composition) Resin test pieces were produced in the same manner as in Example 1, and each test was performed. The results are shown in Table 1.

<Example 5>
(Synthesis of Layered _Titanate ) Layered titanate K _0.80 Li _0.266 Ti _1.733 O ₄ was synthesized under the same conditions as in Example 1.

  (Synthesis of Organized Layered Titanic Acid) After diluting 80 g of 35% hydrochloric acid with 8 kg of deionized water, 83 g of 12-aminododecanoic acid was added and dissolved. Further, 130 g of the layered titanate was added and reacted at 80 ° C. for 1 hour, and then separated by suction filtration. After washing with dilute hydrochloric acid, it was dried in air at 40 ° C. Furthermore, it was dried at 160 ° C. under reduced pressure for 12 hours to obtain organically modified layered titanic acid in which 73 equivalent% of hydrogen ions or hydronium ions remained with respect to the potassium / and lithium ion part of the titanate and the layers were swollen. It was. The obtained organically modified layered titanic acid had an average major axis of 25 μm and an average thickness of 4.6 μm.

  (Production and Evaluation of Biodegradable Resin Composition) Resin test pieces were produced in the same manner as in Example 1, and each test was performed. The results are shown in Table 1.

<Example 6>
(Synthesis of Layered _Titanate ) Layered titanate K _0.80 Li _0.266 Ti _1.733 O ₄ was synthesized under the same conditions as in Example 1.

(Synthesis of layered titanic acid) 65 g of K _0.80 Li _0.266 Ti _1.733 O ₄ was dispersed in 1 kg of deionized water, and 28 g of 35% hydrochloric acid was added. After stirring for 1.5 hours, separation and washing were performed to obtain layered titanic acid in which K ions and Li ions were exchanged with hydrogen ions or hydronium ions. The K ion exchange rate was 72 equivalent%, and the Li ion exchange rate was 99 equivalent% or more. The K ₂ O remaining amount after drying of the obtained layered titanic acid was 6.2%.

  (Synthesis of Organized Layered Titanic Acid) 50 g of the above undried layered titanic acid was dispersed in 4 kg of deionized water, and 63 g of dodecylmethylbis (hydroxyethyl) ammonium chloride was added while heating and stirring at 80 ° C. After continuing heating and stirring for 1 hour, it was filtered out. After thoroughly washing with hot water at 80 ° C., it was dried at 40 ° C. in air. Furthermore, it was dried at 160 ° C. under reduced pressure for 12 hours, and the organic layered titanic acid in which the interlayer was swollen while 72 equivalent% of hydrogen ions or hydronium ions remained in the potassium / and lithium ion part of the titanate. Got. The obtained organically modified layered titanic acid had an average major axis of 22 μm and an average thickness of 4.2 μm.

  (Production and Evaluation of Biodegradable Resin Composition) Resin test pieces were produced in the same manner as in Example 1, and each test was performed. The results are shown in Table 1.

<Comparative Example 1>
(Synthesis of Layered _Titanate ) Layered titanate K _0.80 Li _0.266 Ti _1.733 O ₄ was synthesized under the same conditions as in Example 1.

(Synthesis of layered titanic acid) 65 g of K _0.80 Li _0.266 Ti _1.733 O ₄ was dispersed and stirred in 5 kg of 1.75% hydrochloric acid, separated and washed three times, and K ion and Li ion were combined with hydrogen ion or hydronium ion. The layered titanic acid was replaced with A layered titanic acid having a K ion exchange rate of 97 equivalent% and a Li ion exchange rate of 99 equivalent% or more was obtained. The residual amount of K ₂ O after drying of the layered titanic acid was 0.6%.

(Synthesis of organic layered titanic acid)
18 g of the undried layered titanic acid was dispersed in 600 g of water, and 285 g of a 0.6% 3-methoxypropylamine aqueous solution was added with stirring. The mixture was stirred for about 1 hour to obtain an organically modified layered titanic acid.

(Synthesis of organic layered titanic acid)
Subsequently, 200 g of 8% dodecylmethylbis (hydroxyethyl) ammonium chloride water / isopropanol solution was added with stirring. Stirring was continued for 1 hour and then filtered out. After washing with 800 g of hot water three times, it was dried in air at 40 ° C. Furthermore, it dried under reduced pressure at 160 degreeC for 12 hours, and obtained the organic-ized layered titanic acid. The obtained organically layered titanic acid had an average major axis of 20 μm and an average thickness of 4.6 μm.

  (Preparation and Evaluation of Biodegradable Resin Composition) A resin test piece was prepared in the same manner as in Example 1, and each test was performed. The results are shown in Table 1.

  <Comparative Example 2> Resin test pieces of only polylactic acid (Tm = 169 ° C., Tg = 60 ° C.) were prepared and tested. The results are shown in Table 1.

  <Comparative Example 3> A comparative resin composition was prepared using Somasif MEE (manufactured by Coop Chemical Co., Ltd.) as a commercially available layered silicate filler. A resin test piece was prepared in the same manner as in Example 1 and added to polylactic acid so as to have an ash content of 5%, and each test was performed. The results are shown in Table 1.

表１に示すように本発明に従う実施例１〜６の樹脂組成物は、比較例２のポリ乳酸のみと比較して、曲げ弾性率が飛躍的に向上しており機械強度に優れている。また、重量平均分子量の低下が少なく、フローレートからもわかるように溶融粘度の低下が抑えられている。それにより、融点付近での熱膨張率、加水分解による物性低下を抑制することができ、高強度だけでなく寸法安定性、耐久性を兼ね備えた樹脂組成物が得られた。さらにその中でも実施例１〜５は、有機化層状チタン酸を合成する際に、層状チタン酸塩に、特定量の酸と層間膨潤作用のある塩基性化合物類をワンポットで該層状チタン酸塩を膨潤させることにより、最も高機能を有した樹脂組成物を得た。比較例１及び３は、高強度は得られるが、ポリ乳酸の重量平均分子量の低下からフローレートの上昇を引き起こしてしまうため、寸法安定性、耐久性に劣るものであった。

As shown in Table 1, the resin compositions of Examples 1 to 6 according to the present invention have dramatically improved flexural modulus and excellent mechanical strength as compared with the polylactic acid of Comparative Example 2 alone. Further, the decrease in the weight average molecular weight is small, and the decrease in the melt viscosity is suppressed as can be seen from the flow rate. Thereby, the thermal expansion coefficient in the vicinity of the melting point and the decrease in physical properties due to hydrolysis could be suppressed, and a resin composition having not only high strength but also dimensional stability and durability was obtained. Furthermore, in Examples 1-5, when synthesizing the organically modified layered titanate, the layered titanate is mixed with a specific amount of acid and basic compounds having an interlayer swelling action in one pot. By swelling, a resin composition having the highest function was obtained. In Comparative Examples 1 and 3, although high strength was obtained, the flow rate was increased due to the decrease in the weight average molecular weight of polylactic acid, so that the dimensional stability and durability were inferior.

Claims (7)

A biodegradable resin composition comprising polylactic acid and nanosheeted layered titanic acid. A biodegradable resin composition comprising 100 parts by weight of polylactic acid and 0.5 to 100 parts by weight of nanosheeted layered titanic acid. Nanosheeted layered titanic acid has the general formula
A _x My □ _z Ti _{2- (y + z)} O ₄ (1)
[Wherein, A and M represent 1 to 3 valent metals different from each other, and □ represents a defect site of Ti. x is a positive real number satisfying 0 <x <1.0, and y and z are each 0 or a positive real number satisfying 0 <y + z <1.0],
(1) treating with acid or warm water and replacing A and / or M ions with hydrogen and / or hydronium ions;
(2) a step of causing a basic compound having an interlayer swelling action to act and swelling or peeling the interlayer;
The biodegradable resin composition according to claim 1, wherein the biodegradable resin composition is a nanosheet-like layered titanic acid obtained by a production method comprising: Nanosheeted layered titanic acid has the general formula
A _x My □ _z Ti _{2- (y + z)} O ₄ (1)
[Wherein, A and M represent 1 to 3 valent metals different from each other, and □ represents a defect site of Ti. x is a positive real number satisfying 0 <x <1.0, and y and z are each 0 or a positive real number satisfying 0 <y + z <1.0],
(1) treating with acid or warm water and replacing A and / or M ions with hydrogen and / or hydronium ions;
(2) a step of causing a basic compound having an interlayer swelling action to act and swelling or peeling the interlayer;
The biodegradable resin composition according to claim 1, wherein the biodegradable resin composition is a nanosheet-formed layered titanic acid obtained by a production method in which one is performed in one pot. Nanosheeted layered titanic acid has the general formula
B _m C _n □ _{(y + z)} Ti _{2- (y + z)} O ₄ (2)
[In the formula, B represents a basic compound having an interlayer swelling action, C represents hydrogen and / or hydronium ion, and □ represents a defect site of Ti. m is a positive real number that satisfies 0.1 <m <0.7, n is a positive real number that satisfies 0.3 <n <0.9, and more preferably, n is 0.5 <n < It is a positive real number that satisfies 0.8. The sum of m and n corresponds to x in the general formula (1). The biodegradation according to any one of claims 1 to 4, wherein y and z are nanosheet-formed layered titanic acid represented by 0 or a positive real number satisfying 0 <y + z <1.0, respectively. Resin composition. General formula
B _m C _n □ _{(y + z)} Ti _{2- (y + z)} O ₄ (2)
[In the formula, B represents a basic compound having an interlayer swelling action, C represents hydrogen and / or hydronium ion, and □ represents a defect site of Ti. m is a positive real number that satisfies 0.1 <m <0.7, n is a positive real number that satisfies 0.3 <n <0.9, and more preferably, n is 0.5 <n < It is a positive real number that satisfies 0.8. The sum of m and n corresponds to x in the general formula (1). And y and z are 0 or a positive real number satisfying 0 <y + z <1.0, respectively]. General formula
A _x My □ _z Ti _{2- (y + z)} O ₄ (1)
[Wherein, A and M represent 1 to 3 valent metals different from each other, and □ represents a defect site of Ti. x is a positive real number satisfying 0 <x <1.0, and y and z are each 0 or a positive real number satisfying 0 <y + z <1.0],
(1) treating with acid or warm water and replacing A and / or M ions with hydrogen and / or hydronium ions;
(2) a step of causing a basic compound having an interlayer swelling action to act and swelling or peeling the interlayer;
The manufacturing method of the nanosheet-ized layered titanic acid obtained by the manufacturing method which performs this in one pot.