JP5477567B2 - Polylactic acid resin composition - Google Patents

Description

  The present invention relates to a polylactic acid resin composition, and more particularly to a resin composition containing a polylactic acid resin and a phenylphosphonic acid manganese salt.

From the standpoint of protecting the natural environment, research on aliphatic polyester that is biodegradable in the natural environment has been energetically conducted. Among them, polylactic acid resin has a high melting point of 160 to 180 ° C. and is excellent in transparency. Therefore, for example, packaging materials such as containers and films, clothing, floor mats, fiber materials such as automobile interior materials, and electrical / electronic products. Expected to be a molding material for housings and parts.
However, since the polylactic acid resin has a slow crystallization rate, the molded product tends to have a low degree of crystallinity, especially when it is manufactured by injection molding or the like that is not stretched, and softens when the glass transition temperature exceeds about 60 ° C. Has the disadvantage of being easy to do. In order to increase the crystallinity, an attempt has been made to increase the mold temperature at the time of injection molding and to increase the cooling time in the mold. Has a problem. In order to produce polylactic acid resin molded products with high productivity and use them in a wide range of applications, attempts have been made to increase the crystallization speed and the degree of crystallinity, and to improve the moldability and heat resistance.

  In general, a method of adding a crystal nucleating agent is known as a method for increasing the crystallization speed of a polylactic acid resin. The crystal nucleating agent serves as a primary crystal nucleus of the crystalline polymer, promotes crystal growth, refines the crystal size, and increases the crystallization speed. As a crystal nucleating agent for polylactic acid resin, inorganic particles composed of talc or boron nitride having a specific particle size or less (Patent Document 1), an amide compound represented by a specific formula (Patent Document 2), and a specific formula Sorbitol-based derivatives (Patent Document 3), and phosphoric acid ester metal salts (Patent Document 4) represented by a specific formula are disclosed. Further, it is disclosed that a specific metal salt of a phosphonic acid compound, specifically zinc phenylphosphonate, exhibits excellent performance (Patent Document 5).

JP-A-8-3432 Japanese Patent Laid-Open No. 10-87975 JP-A-10-158369 JP 2003-192883 A International Publication No. 2005/097894

As described above, various crystal nucleating agents have been proposed in order to increase the crystallization speed and degree of crystallization of polylactic acid resin. In recent years, in order to realize higher moldability and heat resistance of polylactic acid resin. Furthermore, development of a more effective crystal nucleating agent is desired.
Accordingly, an object of the present invention is to provide a resin composition comprising a crystal nucleating agent suitable for promoting crystallization of a polylactic acid resin and a polylactic acid resin.

As a result of intensive studies to solve the above problems, the present inventors have increased the crystallization rate of polylactic acid resin by adding a manganese salt of a specific phosphonic acid compound as a crystal nucleating agent to polylactic acid resin. And it discovered that the polylactic acid resin composition excellent in heat resistance and moldability was obtained, and completed this invention.

That is, this invention relates to the polylactic acid resin composition characterized by including the polylactic acid resin and the manganese salt of the phenylphosphonic acid compound represented by Formula (1) as a 1st viewpoint.
(Wherein R ¹ and R ² each independently represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxycarbonyl group having 1 to 10 carbon atoms.)
As a second aspect, the polylactic acid according to the first aspect, containing 0.01 to 10 parts by mass of a manganese salt of the phenylphosphonic acid compound represented by the formula (1) with respect to 100 parts by mass of the polylactic acid resin. The present invention relates to a resin composition.
As a 3rd viewpoint, it is related with the crystal nucleating agent which consists of manganese salt of the phenylphosphonic acid compound represented by Formula (1).
(Wherein R ¹ and R ² each independently represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxycarbonyl group having 1 to 10 carbon atoms.)

  The polylactic acid resin composition of the present invention has improved crystallization accelerating effect of polylactic acid resin by using a phenylphosphonic acid manganese salt as a crystal nucleating agent, and thus has excellent heat resistance and molding processability. A polylactic acid resin composition can be provided.

1 is a scanning microscope (SEM) image of a light pink powder of manganese phenylphosphonate monohydrate produced in Synthesis Example 1. FIG.

The polylactic acid resin composition of the present invention is characterized by containing a manganese salt of a specific phenylphosphonic acid compound and a polylactic acid resin.
Hereinafter, the present invention will be described in more detail.

The phenylphosphonic acid compound used for the manganese salt of the phenylphosphonic acid compound used in the present invention is a compound represented by the following general formula (1).

In the phenylphosphonic acid compound represented by the above formula (1), R ¹ and R ² in the formula are hydrogen atoms; methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, an alkyl group having 1 to 10 carbon atoms such as tert-butyl group; an alkoxycarbonyl group having 1 to 10 carbon atoms such as methoxycarbonyl group and ethoxycarbonyl group. R ¹ and R ² may be the same or different.

Specific examples of the phenylphosphonic acid compound represented by the above formula (1) include phenylphosphonic acid, 4-methylphenylphosphonic acid, 4-ethylphenylphosphonic acid, 4-n-propylphenylphosphonic acid, 4-isopropylphenyl. Phosphonic acid, 4-n-butylphenylphosphonic acid, 4-isobutylphenylphosphonic acid, 4-tert-butylphenylphosphonic acid, 3,5-dimethoxycarbonylphenylphosphonic acid, 3,5-diethoxycarbonylphenylphosphonic acid, 2 , 5-dimethoxycarbonylphenylphosphonic acid, 2,5-diethoxycarbonylphenylphosphonic acid and the like.
As these compounds, commercially available products can be preferably used as they are.

The manganese compound used for producing the manganese salt of the phenylphosphonic acid compound used in the present invention is not particularly limited, and sulfates, nitrates, chlorides, carbonates, acetates, oxides, hydroxides, and the like can be used. .
Commercially available products can also be suitably used as the above compounds.

In order to produce a manganese salt of a phenylphosphonic acid compound, the phenylphosphonic acid compound and the manganese compound are first mixed and reacted in a suitable medium.
Although it does not specifically limit as a medium used here, It is preferable that the phenylphosphonic acid compound which is a raw material is soluble from the surface of reaction efficiency. In consideration of recovering the final product, a solvent in which phenylphosphonic acid manganese salt is hardly soluble is preferable.
Examples of such solvents include water; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; nitriles such as acetonitrile; ethers such as tetrahydrofuran; alcohols such as methanol, ethanol, 1-propanol, and 2-propanol; Amides such as N, N-dimethylformamide, N, N-dimethylacetamide and N-methyl-2-pyrrolidone; Sulfoxides such as dimethyl sulfoxide; Aliphatic hydrocarbons such as n-hexane and n-heptane; benzene, Aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as dichloromethane, chloroform, 1,2-dichloroethane, and chlorobenzene. These solvents may be used alone or in combination of two or more. Among these, it is more preferable to use water in consideration of ease of handling and economy.

  In the above reaction, the amount of the phenylphosphonic acid compound and the manganese compound charged is preferably in the molar ratio of the phenylphosphonic acid compound: manganese compound = 2: 1 to 1: 100.

The actual procedure of the reaction is performed, for example, by adding the phenylphosphonic acid compound solution to a solution or slurry containing the manganese compound as a raw material. Examples of the solvent used in the solution or slurry containing the manganese compound or the solution of the phenylphosphonic acid compound include the above-mentioned medium. At this time, it is preferable to drop the solution or slurry while stirring with a stirring blade or the like.
Although the reaction temperature at this time will not be specifically limited if it is more than the freezing point of a solvent to be used and below a boiling point, Usually, it is suitably selected from the range of 0-250 degreeC. For example, in the case of a reaction in water, the temperature is 0 to 100 ° C, preferably 10 to 100 ° C. The reaction temperature can affect the size of the produced phenylphosphonic acid manganese salt. That is, the higher the reaction temperature, the higher the solubility of the precipitated phenylphosphonic acid manganese salt, so that the product (phenylphosphonic acid manganese salt) is more likely to be redissolved and recrystallized, and the size of the product increases. It's easy to do. For this reason, when manufacturing a phenylphosphonic acid manganese salt with a smaller particle diameter, it is desirable to maintain the temperature of the said reaction at 30 degrees C or less.

In addition, when the reaction is performed in an aqueous medium, particularly in water, when the pH range of the reaction mixture becomes acidic, the solubility of the resulting phenylphosphonic acid manganese salt increases, and the product (phenylphosphonic acid manganese salt for the above reasons). ) Is likely to increase in size. For this reason, when manufacturing a phenylphosphonic acid manganese salt with a smaller particle diameter, you may neutralize by adding a base to a reaction mixture.
Although it does not specifically limit as a base which neutralizes the said reaction mixture, For example, sodium hydroxide, sodium carbonate, sodium hydrogencarbonate etc. can be used.
Specifically, for example, an aqueous solution of these bases is mixed with an aqueous solution of a phenylphosphonic acid compound represented by the above formula (1) or added to the reaction mixture after completion of the reaction.

After the completion of the reaction, the medium is filtered or distilled off, and then washed with a solvent as necessary and dried to obtain a phenylphosphonic acid manganese salt. In addition, it is preferable that the manganese salt obtained does not contain an unreacted phenylphosphonic acid compound.
The drying temperature at this time can be appropriately selected depending on the type of medium, and reduced pressure conditions may be applied.
When water is used as the medium, the drying temperature is preferably 100 to 500 ° C at normal pressure, more preferably 120 to 200 ° C. If the temperature is lower than 100 ° C, the medium (water) cannot be completely removed, and if the temperature is higher than 500 ° C, decomposition of the phenylphosphonic acid manganese salt may be induced.

The phenylphosphonic acid manganese salt obtained through the above production method has a fine plate shape. The major axis length is 0.05 to 1 μm, preferably 0.05 to 0.5 μm.
In addition, the thus obtained phenylphosphonic acid manganese salt can be mixed with a mixer having shearing force such as a homomixer, a Henschel mixer, a Ladige mixer, a ball mill, a pin disc mill, a pulverizer, an inomizer as required. Further, a finer shape can be obtained by using a pulverizer such as a counter jet mill. Further, a finer shape can be obtained with a wet pulverizer such as water, an organic solvent that can be mixed with water, and a ball mill, a bead mill, a sand grinder, an attritor, or an optimizer using a mixed solution thereof.

  A crystal nucleating agent comprising a manganese salt of phenylphosphonic acid represented by the above formula (1) is also an object of the present invention.

The polylactic acid resin contained in the polylactic acid resin composition of the present invention includes a homopolymer or copolymer of polylactic acid. When the polylactic acid resin is a copolymer, the arrangement pattern of the copolymer may be any of random copolymer, alternating copolymer, block copolymer, and graft copolymer. Further, it may be a blend polymer with other resin mainly composed of polylactic acid homopolymer or copolymer. Examples of the other resin include biodegradable resins other than the polylactic acid resin described later, general-purpose thermoplastic resins, and general-purpose thermoplastic engineering plastics.
The polylactic acid is not particularly limited, and examples thereof include those obtained by ring-opening polymerization of lactide and those obtained by direct polycondensation of D-form, L-form, racemate, etc. of lactic acid. The number average molecular weight of polylactic acid is generally about 10,000 to 500,000. A polylactic acid resin obtained by crosslinking with a crosslinking agent using heat, light, radiation, or the like can also be used.

Examples of biodegradable resins other than polylactic acid resins include poly-3-hydroxybutyric acid, polyhydroxyalkanoic acids such as 3-hydroxybutyric acid and 3-hydroxyhexanoic acid copolymer, polycaprolactone, and polybutylene succinate. , Polybutylene succinate / adipate, polybutylene succinate / carbonate, polyethylene succinate, polyethylene succinate / adipate, polyvinyl alcohol, polyglycolic acid, modified starch, cellulose acetate, chitin, chitosan, lignin and the like.

Examples of general-purpose thermoplastic resins include polyethylene (PE), polyethylene copolymer, polypropylene (PP), polypropylene copolymer, polybutylene (PB), ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer Polyolefin resins such as (EEA) or poly (4-methyl-1-pentene), polystyrene (PS), high impact polystyrene (HIPS), acrylonitrile-styrene copolymer (AS), or acrylonitrile-butadiene-styrene copolymer Examples thereof include polystyrene resins such as coalescence (ABS), vinyl chloride resins, polyurethane resins, phenol resins, epoxy resins, amino resins, and unsaturated polyester resins.
Examples of general-purpose engineering plastics include polyamide resins, polycarbonate resins, polyphenylene ether resins, modified polyphenylene ether resins, polyester resins such as polyethylene terephthalate (PET) or polybutylene terephthalate (PBT), polyacetal resins, polysulfone resins, polyphenylene sulfide resins. And polyimide resin.

  The addition amount of the phenylphosphonic acid manganese salt in the polylactic acid resin composition is preferably 0.01 to 10 parts by mass in terms of anhydride with respect to 100 parts by mass of the polylactic acid resin. More preferably, it is 0.02 to 5 parts by mass, and still more preferably 0.03 to 2 parts by mass. If the addition amount of the phenylphosphonic acid manganese salt is less than 0.01 parts by mass, it is difficult to sufficiently increase the crystallization rate of the polylactic acid resin. A polylactic acid resin having a high crystallization rate can be obtained even when the amount exceeds 10 parts by mass, but the crystallization rate is not further increased.

  In the present invention, the method for blending the phenylphosphonic acid manganese salt into the polylactic acid resin is not particularly limited and can be carried out by a known method. For example, polylactic acid resin and phenylphosphonic acid manganese salt may be mixed with various mixers and kneaded using a single screw or twin screw extruder. Kneading is usually performed at a temperature of about 150 to 220 ° C. Moreover, the method of producing | generating the masterbatch containing phenylphosphonic acid manganese salt by high concentration, and adding this to polylactic acid resin is also possible. In addition, phenylphosphonic acid manganese salt can be added at the polymerization stage of the polylactic acid resin.

  A known inorganic filler can be used for the polylactic acid resin composition of the present invention. For example, glass fiber, carbon fiber, talc, mica, silica, kaolin, clay, wollastonite, glass beads, glass flake, potassium titanate, calcium carbonate, magnesium sulfate, titanium oxide and the like can be mentioned. The shape of these inorganic fillers may be any of fibrous, granular, plate-like, needle-like, spherical, and powder. These inorganic fillers can be used within 300 parts by mass with respect to 100 parts by mass of the polylactic acid resin.

  A known flame retardant can be used in the polylactic acid resin composition of the present invention. For example, halogen flame retardants such as bromine and chlorine, antimony flame retardants such as antimony trioxide and antimony pentoxide, inorganic flame retardants such as aluminum hydroxide, magnesium hydroxide and silicone compounds, red phosphorus and phosphoric acid Phosphorus flame retardants such as esters, ammonium polyphosphate, phosphazene, melamine, melam, melem, melon, melamine cyanurate, melamine phosphate, melamine pyrophosphate, melamine polyphosphate, melamine polymelamine melam melem double salt, alkyl Examples include melamine phosphonate, melamine phenylphosphonate, melamine sulfate, and melamine methanesulfonate flame retardant, and fluororesin such as PTFE. These flame retardants can be used within 200 parts by mass with respect to 100 parts by mass of the polylactic acid resin.

  In addition to the above components, heat stabilizers, light stabilizers, UV absorbers, antioxidants, impact modifiers, antistatic agents, pigments, colorants, mold release agents, lubricants, plasticizers, compatibilizers, foaming Various commonly used in the production of general synthetic resins, such as agents, fragrances, antibacterial and antifungal agents, various coupling agents such as silane, titanium, and aluminum, other various fillers, and other crystal nucleating agents Can be used in combination with additives.

  The polylactic acid resin composition of the present invention can be applied with molding methods such as general injection molding, blow molding, vacuum molding and compression molding, and various molded products can be easily obtained through these moldings. .

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited by this.

[Synthesis Example 1]
To a 500 mL reaction flask equipped with a stirrer, 19.8 g (0.1 mol) of manganese (II) chloride tetrahydrate [special grade manufactured by Wako Pure Chemical Industries, Ltd.] and 248 g of water were added and stirred to prepare manganese chloride. An aqueous solution was prepared. An aqueous solution in which 15.8 g (0.1 mol) of phenylphosphonic acid [manufactured by Nissan Chemical Industries, Ltd.] was dissolved in 90 g of water and 40 mL of 5N aqueous sodium hydroxide solution were stirred in this aqueous solution at room temperature (approximately 25 ° C.). (0.2 mol) of the mixed solution was dropped in about 5 minutes. After completion of the dropwise addition, the produced slurry was filtered, and the crystals were thoroughly washed with water. The obtained wet product was dried at 200 ° C. for 12 hours to obtain 22.5 g of manganese phenylphosphonate monohydrate as a light pink powder (yield 98%).
FIG. 1 shows an SEM image of the obtained manganese phenylphosphonate monohydrate (JEM-7400F, field emission scanning electron microscope manufactured by JEOL Ltd.).

  The obtained manganese phenylphosphonate was subjected to TG-DTA measurement [ThermoPlus2 / TG-DTA8120 manufactured by Rigaku Corporation]. In the measurement, the temperature was raised from room temperature (approximately 25 ° C.) to 200 ° C. at 10 ° C./min, and then cooled at 10 ° C./min. As a result, a weight loss of about 8% corresponding to one water molecule was observed at 170 to 200 ° C. when the temperature was raised, and a similar weight increase was observed from about 130 ° C. during the cooling. From this, it was suggested that manganese phenylphosphonate immediately after drying is an anhydride, but it quickly becomes a monohydrate when cooled to room temperature in air.

[Synthesis Example 2]
To a 300 mL reaction flask equipped with a stirrer, manganese oxide (II) [manufactured by Wako Pure Chemical Industries, Ltd.] 10.0 g (0.14 mol) and water 90 g were added to prepare an aqueous slurry of manganese oxide. To this slurry, an aqueous solution in which 22.1 g (0.14 mol) of phenylphosphonic acid [manufactured by Nissan Chemical Industries, Ltd.] was dissolved in 125 g of water was added dropwise over about 10 minutes while stirring at room temperature (about 25 ° C.). After stirring for 5 hours as it was, the slurry was filtered, and the crystals were thoroughly washed with water. The obtained wet product was dried at 200 ° C. for 12 hours to obtain 24.4 g of a light pink powder manganese phenylphosphonate monohydrate (yield 76%).

[Comparative Synthesis Example 1]
To a 500 mL reaction flask equipped with a stirrer, 13.6 g (0.1 mol) of zinc chloride [manufactured by Wako Pure Chemical Industries, Ltd.] and 200 g of water were added and stirred to prepare an aqueous zinc chloride solution. An aqueous solution in which 15.8 g (0.1 mol) of phenylphosphonic acid [manufactured by Nissan Chemical Industries, Ltd.] was dissolved in 90 g of water and 40 mL of 5N aqueous sodium hydroxide solution were stirred in this aqueous solution at room temperature (approximately 25 ° C.). (0.2 mol) of the mixed solution was dropped in about 5 minutes. After completion of the dropwise addition, the produced slurry was filtered, and the crystals were thoroughly washed with water. The obtained wet product was dried at 200 ° C. for 12 hours to obtain 20.8 g of white powdered zinc phenylphosphonate (yield 94%).

[Comparative Synthesis Example 2]
To a 300 mL reaction flask equipped with a stirrer, 10.0 g (0.12 mol) of zinc oxide [Hakusui Tech Co., Ltd., 2 types] and 90 g of water were added to prepare an aqueous slurry of zinc oxide. To this slurry, an aqueous solution in which 19.4 g (0.12 mol) of phenylphosphonic acid [manufactured by Nissan Chemical Industries, Ltd.] was dissolved in 110 g of water was added dropwise over about 10 minutes with stirring at room temperature (about 25 ° C.). After stirring for 5 hours as it was, the slurry was filtered, and the crystals were thoroughly washed with water. The obtained wet product was dried at 120 ° C. for 12 hours to obtain 25.5 g of white powdered zinc phenylphosphonate (yield 96%).

[Example 1]
100 parts by mass of polylactic acid resin [Toyota Eco Plastics U'z S-09 manufactured by Toyota Motor Corporation] was dissolved in 1,900 parts by mass of chloroform to prepare a 5% by mass polylactic acid resin solution. After adding 1 part by mass of manganese phenylphosphonate monohydrate obtained in Synthesis Example 1 as a crystal nucleating agent to this solution, ultrasonic treatment for 30 minutes [Gascro Industry Co., Ltd. (currently GL Science Co., Ltd.) Large ultrasonic bath (150 W)], followed by stirring for 3 hours, and further subjected to ultrasonic treatment for 30 minutes to disperse the crystal nucleating agent in the solution. The obtained polylactic acid resin composition was cast on a petri dish and the solvent was removed on a hot plate at 50 ° C. to obtain a polylactic acid resin film in which the crystal nucleating agent was dispersed.
This sample was cut into small pieces and subjected to DSC measurement [ThermoPlus2 / DSC8230, manufactured by Rigaku Corporation]. In the measurement, the temperature was raised to 200 ° C. at 10 ° C./min under a nitrogen stream, maintained for 5 minutes, and then cooled at 5 ° C./min. The crystallization temperature Tc and the heat generation amount ΔH were measured from the temperature at the peak of the exothermic peak derived from the crystallization of the polylactic acid resin observed during cooling. The obtained results are shown in Table 1.

[Example 2]
In Example 1, the same operation and measurement were performed except that the phenyl phosphonate manganese monohydrate obtained in Synthesis Example 2 was used as the crystal nucleating agent. The obtained results are shown in Table 1. [Comparative Example 1]
In Example 1, the same operation and measurement were performed except that the zinc phenylphosphonate obtained in Comparative Synthesis Example 1 was used as the crystal nucleating agent. The obtained results are shown in Table 1.
[Comparative Example 2]
In Example 1, the same operation and measurement were performed except that the zinc phenylphosphonate obtained in Comparative Synthesis Example 2 was used as the crystal nucleating agent. The obtained results are shown in Table 1.
[Comparative Example 3]
In Example 1, the same operation and measurement were performed except that the crystal nucleating agent was not used. The obtained results are shown in Table 1.

  As shown in Table 1, the resin compositions of Example 1 and Example 2 using manganese phenylphosphonate monohydrate were compared with Comparative Synthesis Example 1 and Comparative Synthesis Example 2 using zinc phenylphosphonate. Results indicating high crystallization temperature and crystallization exotherm were obtained.

Claims (2)

A polylactic acid resin composition comprising a polylactic acid resin and a crystal nucleating agent comprising a manganese salt of a phenylphosphonic acid compound represented by formula (1).
(Wherein R ¹ and R ² each independently represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, or an alkoxycarbonyl group having 1 to 10 carbon atoms.) The polylactic acid according to claim 1, comprising 0.01 to 10 parts by mass of a crystal nucleating agent comprising a manganese salt of a phenylphosphonic acid compound represented by the formula (1) with respect to 100 parts by mass of the polylactic acid resin. Resin composition.