JP2006328369A - Polylactic acid-based molded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molded article composed of a polylactic acid-based polymer and having excellent transparency and heat resistance, in which evaporation, oozing-out and extraction (bleedout) of lactide, etc., are suppressed when used as a molded article and further, odor emitted when used under heating is suppressed. <P>SOLUTION: The molded article is composed of a polylactic acid resin composition obtained by formulating (A) a polylactic acid resin having ≥50,000 weight-average molecular weight with (B) a poly(meth)acrylate and/or a polyvinyl compound having ≥60°C glass transition temperature. In the molded article, melting calorie (ΔHm) of crystal of the molded article in DSC temperature-raising measurement is ≤10 J/g and lactide content in the molded article is ≤2 mass%. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a molded article having polylactic acid as a main component and excellent in transparency, heat resistance and impact resistance. More specifically, it relates to polylactic acid-based molded products that have no problems such as volatilization, leaching, extraction (bleed out) of lactide, etc. when used as molded products, and odor and deterioration of transparency during heating. is there.

  Polylactic acid has a high melting point and is expected to be a practically excellent biodegradable polymer that can be melt-molded. However, polylactic acid has a low crystallization rate, and there is a limit to use it for a molded product after crystallization. For example, when used as a film, polylactic acid film is said to have the highest tensile strength and elastic modulus among various biodegradable films, and excellent in gloss and transparency, but the glass transition temperature of the resin is relatively low. Since it is low, there was a limit to use as a heat resistant application. Therefore, improvement in heat resistance (thermal deformation temperature) is required (see, for example, Non-Patent Document 1).

  By the way, mixing two or more kinds of polymers is widely known as a polymer blend or a polymer alloy, and is widely used as a method for improving the defects of individual polymers. However, generally, when two kinds of polymers are mixed, many of them are separated into individual phases, and one phase generally has a non-uniform coarse dispersion structure of several μm or more. In the case of such a dispersed form, it is opaque and has low mechanical strength. Further, it tends to cause a ballast effect during discharge during melt-kneading and is often inferior in productivity. On the other hand, in rare cases, two types of polymers may be mixed uniformly. This type of polymer is generally called a compatible polymer or miscible polymer and is expected to exhibit excellent properties. Examples are limited.

  On the other hand, as a method of mixing a resin having compatibility with polylactic acid, it is described that mixing with polymethyl methacrylate having a glass transition temperature of about 100 ° C. improves the glass transition temperature of the resin composition. (For example, Non-Patent Documents 2 to 3), it is described that a resin excellent in hydrolyzability is formed by mixing an α-hydroxycarboxylic acid polymer containing polylactic acid and a poly (meth) acrylate resin (for example, Patent Document 1). ), It is described that an acrylic compound is blended with polylactic acid to obtain a resin composition excellent in weather resistance and molding processability (for example, Patent Document 2), and a polymer having a carbonyl compound in the main chain is vinyl alcohol. It is described that a resin composition excellent in water resistance is produced by mixing a polymer (for example, Patent Document 3), both of which have heat resistance and high temperature. Not at all disclose a technical idea related to sexual improvement, no suggestion of possible solutions.

In general, a considerable amount of lactide, lactic acid, linear lactic acid oligomer, or cyclic lactic acid oligomer remaining in the polylactic acid remains due to unreacted and / or hydrolysis. Such polylactic acid containing a considerable amount of lactic acid, linear lactic acid oligomer or cyclic lactic acid oligomer has low thermal stability during molding and is easily hydrolyzed under normal use conditions. Even when a molded article such as a film is produced from such a composition, there is a great disadvantage that the strength drops in a relatively short period of time and is inferior in practicality. Furthermore, when used as a molded product under high temperature and high humidity conditions, or when used in contact with water or a solvent, lactide and lactic acid oligomers contained in the molded product are volatilized, exuded, and extracted (bleed out). And there was a problem of generating an odor. Although the technology related to the control of the amount of lactide and lactic acid oligomer is disclosed (for example, Patent Document 4), this technology only mentions antibacterial and antifungal properties due to lactide and lactic acid oligomer. No technical idea about volatilization, exudation, extraction (bleed out) suppression or odor reduction is disclosed, and no solution is suggested.
"Biodegradable chemicals and plastics", CMC Corporation, 2000, p. 147) "Polymer" 39 (26), p6891 (1998) “Macromolecule Chemical Physics” 201, p.1295 (2000) JP-A-8-59949 (paragraph [0006]) JP 2002-155207 A (paragraphs [0001] to [0008]) JP-A-6-322217 (paragraphs [0001] to [0007]) JP 2000-328422 A (paragraphs [0007] to [0030])

  The problem of the present invention is that it has excellent transparency, mechanical properties, heat resistance, volatilization, leaching, extraction (bleed out), extraction (bleed out), and odor during heating use, which could not be achieved by the prior art. Another object of the present invention is to provide a polylactic acid-based molded product such as a fiber and a film.

In order to solve the above problems, the polylactic acid-based molded article of the present invention mainly has the following configuration. That is,
(A) a polylactic acid resin having a weight average molecular weight of 50,000 or more as a component;
(B) Poly (meth) acrylate as a component and / or a polyvinyl compound having a glass transition temperature of 60 ° C. or higher,
A molded product comprising a polylactic acid resin composition, wherein the crystal melting heat amount (ΔHm) of the molded product in DSC temperature rise measurement is 10 J / g or less, and the lactide content in the molded product Is a molded product having a content of 2 mass% or less.
It is.

  The polylactic acid-based molded article of the present invention has excellent transparency, mechanical properties, and heat resistance, which could not be achieved by the prior art, and also volatilization and leaching of plasticizers and lactides, extraction (bleed out), and heating. It is a molded product in which the odor during use is suppressed, and can be used more widely than ever in the field of molded products such as sheets including heat-resistant containers. Specifically, it can be preferably used for shaped articles such as various shape holders such as blister packs, containers such as food trays and beverage cups, and display bottles for beverage vending machines.

  Furthermore, the molded product of the present invention has the advantage that the proportion of plant-derived raw materials used (plant degree) is higher than that of conventional plastics, and is highly biodegradable in the natural environment. Has the advantage of being easily disassembled.

  Moreover, the polylactic acid-type molded article of the preferable aspect of this invention is a molded article which has impact resistance and also suppressed the deterioration of transparency at the time of heating use.

  The aliphatic polyester resin of the present invention greatly contributes to solving environmental problems related to industry and plastic waste.

  In order to satisfy practical mechanical properties, the polylactic acid resin used in the present invention needs to have a weight average molecular weight of 50,000 or more, preferably 80,000 or more, and more preferably 100,000 or more. preferable. The weight average molecular weight here refers to the molecular weight in terms of polymethyl methacrylate (PMMA) measured by gel permeation chromatography.

  Moreover, although the polylactic acid resin concerning this invention is a polymer which has L-lactic acid and / or D-lactic acid as a main component, it may contain other copolymerization components other than lactic acid. Other monomer units include ethylene glycol, propylene glycol, butanediol, heptanediol, hexanediol, octanediol, nonanediol, decanediol, 1,4-cyclohexanedimethanol, neopentyl glycol, glycerin, pentaerythritol. Glycol compounds such as bisphenol A, polyethylene glycol, polypropylene glycol and polytetramethylene glycol, oxalic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, malonic acid, glutaric acid, cyclohexanedicarboxylic acid, terephthalic acid, Isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, bis (p-carboxyphenyl) methane, anthracene dicarboxylic acid, 4,4'-diphenyl ether dicarbo Acids, dicarboxylic acids such as 5-sodium sulfoisophthalic acid, 5-tetrabutylphosphonium isophthalic acid, glycolic acid, hydroxypropionic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxybenzoic acid and other hydroxycarboxylic acids, caprolactone, Examples include lactones such as valerolactone, propiolactone, undecalactone, and 1,5-oxepan-2-one. The copolymerization amount of the other copolymer components is preferably 30 mol% or less, and preferably 10 mol% or less, based on the total monomer components.

  In the present invention, in order to obtain a molded product having particularly high heat resistance, it is preferable to use a polylactic acid resin having a high optical purity of the lactic acid component. Of the total lactic acid component of the polylactic acid resin, it is preferable that the L-form is contained at 80% or more, or the D-form is contained at 80% or more, the L-form is contained at 90% or more, or the D-form is contained at 90% or more. It is particularly preferable that the L-form is contained at 95% or more or the D-form is contained at 95% or more.

  As a method for producing the polylactic acid resin, a known polymerization method can be used, and examples thereof include a direct polymerization method from lactic acid and a ring-opening polymerization method via lactide.

  The melting point of the polylactic acid resin is not particularly limited, but is preferably 120 ° C. or higher, and more preferably 150 ° C. or higher. The melting point of the polylactic acid resin is usually increased by increasing the optical purity of the lactic acid component, and the polylactic acid resin having a melting point of 120 ° C. or higher contains 90% or more of the L form or 90% or more of the D form. In addition, a polylactic acid resin having a melting point of 150 ° C. or higher can be obtained by containing 95% or more of L form or 95% or more of D form.

  The molded product in the present invention includes a polylactic acid resin having a weight average molecular weight of 50,000 or more as the component (A) and a poly (meth) acrylate and / or a polyvinyl compound having a glass transition temperature of 60 ° C. or more as the component (B). It is molded from the blended polylactic acid resin composition.

  The polylactic acid resin composition according to the present invention can be produced by uniformly mixing a solution in which each component is dissolved in a solvent, and then removing the solvent to produce the composition. It is preferable to employ a melt-kneading method, which is a practical production method, without requiring steps such as dissolution and solvent removal. The melt-kneading method is a method for producing by melting and kneading each component. The melt kneading method is not particularly limited, and a commonly used known mixer such as a kneader, roll mill, Banbury mixer, single-screw or twin-screw extruder can be used. Among these, from the viewpoint of productivity, it is preferable to use a single screw or twin screw extruder. The order of mixing is also not particularly limited. For example, polylactic acid and poly (meth) acrylate, a polyvinyl compound having a glass transition temperature of 60 ° C. or higher after dry blending, and a method of using a polylactic acid and poly (poly ( Examples thereof include a method of melt-kneading the master batch and polylactic acid after preparing a master batch in which a (meth) acrylate and a polyvinyl compound having a glass transition temperature of 60 ° C. or higher are melt-kneaded. In addition, if necessary, a method of melt-kneading other additives at the same time, or preparing a master batch in which polylactic acid and other additives are melt-kneaded in advance, then the master batch, polylactic acid, poly (meth) acrylate, glass A method of melt-kneading a polyvinyl compound having a transition temperature of 60 ° C. or higher may be used. Moreover, the temperature at the time of melt kneading is preferably in the range of 190 ° C. to 240 ° C., and more preferably in the range of 200 ° C. to 220 ° C. in order to prevent the deterioration of polylactic acid.

  Since the polylactic acid resin composition according to the present invention is excellent in compatibility or miscibility, the polylactic acid resin composition is excellent in transparency. When the sheet is 0.2 mm thick using the polylactic acid resin composition, A light transmittance of 40% or more in visible light having a wavelength of 400 nm can be obtained. Moreover, in a preferable aspect, a light transmittance of visible light having a wavelength of 400 nm can be obtained at 50% or more. In a more preferred embodiment, one having a light transmittance of 60% or more in visible light having a wavelength of 400 nm can be obtained.

The polylactic acid resin composition according to the present invention may have a structural period of 3 μm or less depending on the type and blending amount of poly (meth) acrylate and / or polyvinyl compound having a glass transition temperature of 60 ° C. or higher. It is preferable because it has both excellent mechanical properties and heat resistance. This structural period may be derived from a fine phase separation structure formed by spinodal decomposition after once compatibilizing during melt kneading, but is not limited thereto. In order to confirm the “fine phase separation structure”, for example, methods such as optical microscope observation and transmission electron microscope observation can be used. The “structural period” can be confirmed by the appearance of a scattering maximum in scattering measurement performed using a light scattering device or a small-angle X-ray scattering device. Note that the light scattering device and the small-angle X-ray scattering device have different optimum measurement regions, so that they are appropriately selected according to the size of the structure period. The existence of the scattering maximum in this scattering measurement is a proof of having a regular phase separation structure with a certain period, and the value of the structure period Λm is the wavelength λ in the scatterer of scattered light and the scattering angle θm that gives the scattering maximum. Using the following formula Λm = (λ / 2) / sin (θm / 2)
Can be calculated.

  Furthermore, the polylactic acid resin composition according to the present invention may be compatible by selecting the type and blending amount of the poly (meth) acrylate to be blended and / or the polyvinyl compound having a glass transition temperature of 60 ° C. or higher, In this case, since it is especially excellent in transparency, it is preferable because it is suitably used in various transparent applications. In general, “compatibility” means that both components are uniformly mixed at the molecular level, and the above-described structural period is at least 0.01 μm or less, and in this case, it is particularly preferable.

  In the present invention, the component (B) and the poly (meth) acrylate of the component (C) described later have at least one monomer selected from acrylate and methacrylate as a structural unit. A monomer may be copolymerized and used. Examples of the acrylate and methacrylate used to constitute the poly (meth) acrylate include acrylates such as methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, cyanoethyl acrylate, and cyanobutyl acrylate, and methyl methacrylate and ethyl. Although methacrylates such as methacrylate, cyclohexyl methacrylate, 2-hydroxyethyl methacrylate and the like can be mentioned, it is preferable to use polymethyl methacrylate for imparting higher high-temperature rigidity.

  When polymethyl methacrylate is used as the poly (meth) acrylate, from the viewpoint of compatibility with the polylactic acid resin, and from the viewpoint of adjusting the melt viscosity in the case of a laminated sheet, the polymethyl methacrylate measured at 230 ° C. according to JIS K7210 The fluidity is preferably 2 g / 10 min or more, more preferably 3 g / 10 min or more, still more preferably 5 g / 10 min or more, and particularly preferably 7 g / 10 min or more.

  The poly (meth) acrylate used in the present invention preferably has a weight average molecular weight of 20,000 to 500,000, more preferably 100,000 to 200,000. If the weight average molecular weight is less than 20,000, the strength of the molded product may be reduced, and if the weight average molecular weight exceeds 500,000, the fluidity during molding may be reduced.

  The method for polymerizing or copolymerizing these monomers is not particularly limited, and known polymerization methods such as bulk polymerization, solution polymerization, and suspension polymerization can be used.

  The (B) component and the later-described (C) component polyvinyl compound in the present invention are polymers of vinyl compounds, and among them, it is necessary to use a compound having a glass transition temperature of 60 ° C. or higher. When the glass transition temperature is less than 60 ° C., the effect of improving the heat resistance of polylactic acid is reduced even when it is compatibilized with polylactic acid. Specific examples of the polyvinyl compound having a glass transition temperature of 60 ° C. or higher include polystyrene, poly (4-acetylstyrene), poly (2-methylstyrene), poly (3-methylstyrene), and poly (4-methylstyrene). , Poly (4-methoxystyrene), poly (4-hydroxystyrene) (polyvinylphenol), poly (2-hydroxymethylstyrene), poly (3-hydroxymethylstyrene), poly (4-hydroxymethylstyrene), etc. Styrene polymer, and poly (benzoyloxyethylene), poly (cyclohexanoyloxyethylene), poly (4-ethoxybenzoyloxyethylene), poly (2-methoxybenzoyloxyethylene), poly (4-methoxybenzoyloxyethylene) ), Poly (4-phenylbenzoyl) Kishiechiren) Various polyvinyl esters such as are mentioned, but it is preferable to use poly terms of compatibility with the polylactic acid resin (4-hydroxystyrene) (polyvinyl phenol).

  The polylactic acid-based molded article of the present invention needs to have a heat of crystal melting (ΔHm) of 10 J / g or less in the DSC temperature rise measurement. Exceeding this range is not preferable because crystallization proceeds greatly when the molded product is heated, leading to deterioration of transparency. In this respect, ΔHm is more preferably 8 J / g or less, and still more preferably 5 J / g or less.

  In order to further maintain the transparency when the molded body is heated, there is a method of suppressing the excessive growth of the crystal of the polylactic acid resin of the component (A) and miniaturizing the crystal. It preferably contains a crystal nucleating agent.

  Such a crystal nucleating agent preferably has good compatibility with the polylactic acid-based resin, and it is preferable to increase the crystallization speed and maintain the transparency of the resin when crystallized. Examples of such crystal nucleating agents include aliphatic carboxylic acid amides, aliphatic carboxylates, aliphatic alcohols, aliphatic carboxylic acid esters, aliphatic / aromatic carboxylic acid hydrazides, melamine compounds, and phenylphosphonic acid metal salts. Can be used.

  Specific examples of such aliphatic carboxylic acid amides include aliphatic monoamides such as lauric acid amide, palmitic acid amide, oleic acid amide, stearic acid amide, erucic acid amide, behenic acid amide, ricinoleic acid amide and hydroxystearic acid amide. Carboxylic acid amides, N-oleyl palmitic acid amide, N-oleyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl oleic acid amide, N-stearyl stearic acid amide, N-stearyl erucic acid amide, methylol stearic acid N-substituted aliphatic monocarboxylic amides such as amide, methylol behenic acid amide, methylene bis stearic acid amide, ethylene bis lauric acid amide, ethylene bis capric acid amide, ethylene bis oleic acid amide, ethylene vinyl Stearic acid amide, ethylene biserucic acid amide, ethylene bisbehenic acid amide, ethylene bisisostearic acid amide, ethylene bishydroxystearic acid amide, butylene bisstearic acid amide, hexamethylene bisoleic acid amide, hexamethylene bisstearic acid Aliphatic biscarboxylic amides such as amide, hexamethylene bisbehenic acid amide, hexamethylene bishydroxystearic acid amide, m-xylylene bisstearic acid amide, m-xylylene bis-12-hydroxystearic acid amide, N, N′-dioleyl sebacic acid amide, N, N′-dioleyl adipic acid amide, N, N′-distearyl adipic acid amide, N, N′-distearyl sebacic acid amide, N, N′-di Stearyl isophthalic acid N-substituted aliphatic carboxylic acid bisamides such as N, N'-distearyl terephthalamide, N-butyl-N'-stearyl urea, N-propyl-N'-stearyl urea, N-stearyl-N N-substituted ureas such as' -stearyl urea, N-phenyl-N'-stearyl urea, xylylene bisstearyl urea, toluylene bisstearyl urea, hexamethylene bisstearyl urea, diphenylmethane bisstearyl urea, diphenylmethane bislauryl urea Can be used. These may be one kind or a mixture of two or more kinds. Among these, aliphatic monocarboxylic acid amides, N-substituted aliphatic monocarboxylic acid amides, and aliphatic biscarboxylic acid amides are preferably used. In particular, palmitic acid amide, stearic acid amide, erucic acid amide, and behenic acid are used. Amide, ricinoleic acid amide, hydroxystearic acid amide, N-oleyl palmitic acid amide, N-stearyl erucic acid amide, ethylene biscapric acid amide, ethylene bisoleic acid amide, ethylene bislauric acid amide, ethylene biserucic acid amide, m -Xylylene bis-stearic acid amide and m-xylylene bis-12-hydroxystearic acid amide are preferably used.

  Specific examples of such aliphatic carboxylates include sodium laurate, potassium laurate, potassium hydrogen laurate, magnesium laurate, calcium laurate, zinc laurate, silver laurate, and lithium myristate. , Sodium myristate, potassium hydrogen myristate, magnesium myristate, calcium myristate, zinc myristate, silver myristate, etc., myristate, lithium palmitate, potassium palmitate, magnesium palmitate, calcium palmitate, zinc palmitate , Copper palmitate, lead palmitate, thallium palmitate, cobalt palmitate, etc., sodium oleate, potassium oleate, magnesium oleate, calcium oleate Oleate such as sodium oleate, zinc oleate, lead oleate, thallium oleate, copper oleate, nickel oleate, sodium stearate, lithium stearate, magnesium stearate, calcium stearate, barium stearate, aluminum stearate, Stearates such as thallium stearate, lead stearate, nickel stearate, beryllium stearate, sodium isostearate, potassium isostearate, magnesium isostearate, calcium isostearate, barium isostearate, aluminum isostearate, zinc isostearate, isostearate Isostearates such as nickel acid, sodium behenate, potassium behenate, magnesium behenate, behenic acid Lucium, barium behenate, aluminum behenate, zinc behenate, nickel behenate, etc., behenates, sodium montanate, potassium montanate, magnesium montanate, calcium montanate, barium montanate, aluminum montanate, montanic acid Montanates such as zinc and nickel montanate can be used. These may be one kind or a mixture of two or more kinds. Particularly, stearic acid salts and montanic acid salts are preferably used, and particularly, sodium stearate, potassium stearate, zinc stearate, and calcium montanate are preferably used.

  Specific examples of the aliphatic alcohol include aliphatic monoalcohols such as pentadecyl alcohol, cetyl alcohol, heptadecyl alcohol, stearyl alcohol, nonadecyl alcohol, eicosyl alcohol, seryl alcohol, and melyl alcohol, Aliphatic polyhydric alcohols such as 6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, cyclopentane-1,2-diol, Cyclic alcohols such as cyclohexane-1,2-diol and cyclohexane-1,4-diol can be used. These may be one kind or a mixture of two or more kinds. In particular, aliphatic monoalcohols are preferably used, and stearyl alcohol is particularly preferably used.

  Specific examples of the aliphatic carboxylic acid ester include lauric acid cetyl ester, lauric acid phenacyl ester, myristic acid cetyl ester, myristic acid phenacyl ester, palmitic acid isopropylidene ester, palmitic acid dodecyl ester, and palmitic acid tetraethyl ester. Aliphatic monocarboxylic acid esters such as dodecyl ester, palmitic acid pentadecyl ester, palmitic acid octadecyl ester, palmitic acid cetyl ester, palmitic acid phenyl ester, palmitic acid phenacyl ester, stearic acid cetyl ester, behenic acid ethyl ester, Monoesters of ethylene glycol such as glycol monolaurate, glycol monopalmitate, glycol monostearate, glycol dilaurate, di Diesters of ethylene glycol such as glycol lumitate and glycol distearate, glycerin monoesters such as monolauric acid glycerin ester, monomyristic acid glycerin ester, monopalmitic acid glycerin ester, monostearic acid glycerin ester, dilauric acid glycerin ester, Glycerin diesters such as dimyristic acid glycerin ester, dipalmitic acid glycerin ester, distearic acid glycerin ester, trilauric acid glycerin ester, trimyristic acid glycerin ester, tripalmic acid glycerin ester, tristearic acid glycerin ester, palmitodiolein, Use glycerol triesters such as palmitodistearin and oleodistearin. Can. These may be one kind or a mixture of two or more kinds. Of these, ethylene glycol diesters are preferred, and ethylene glycol distearate is particularly preferred.

  Specific examples of such aliphatic / aromatic carboxylic acid hydrazides include sebacic acid dibenzoic acid hydrazide, specific examples of melamine compounds, specific examples of melamine cyanurate, polymelate melamine, and phenylphosphonic acid metal salts. For example, phenylphosphonic acid zinc salt, phenylphosphonic acid calcium salt, phenylphosphonic acid magnesium salt, and phenylphosphonic acid magnesium salt can be used.

  The specific addition amount of these transparent nucleating agents is preferably 0.1 to 2.5% by weight, more preferably 0.3 to 2% by weight, particularly preferably based on the whole polylactic acid resin composition. 0.5 to 1.5% by weight. When the added amount is less than 0.1% by weight, the effect as a transparent nucleating agent becomes insufficient, and the heat resistance may be lowered. When the added amount is larger than 2.5% by weight, the transparency may be lowered or the appearance and physical properties may be changed.

  The molded product of the present invention has a lactide content of 2% by mass or less. If the amount of lactide contained in the molded product exceeds 2% by mass, the product will be volatilized, leached, extracted (bleeded) when the molded product is used under high temperature and high humidity conditions, or in contact with water or solvent. Out), and further problems such as the generation of odor during heating use. For example, when used as a packaging material and heated, the surroundings may be soiled, or when food is packaged and heated in water, the contents may be transferred. The melting point of lactide is about 100 ° C., and when heated, sublimation starts at a temperature of 90 ° C. or higher.

  Moreover, when a polylactic acid polymer is heated, a specific odor may be emitted, but this odor is often generated particularly strongly when heated to 100 ° C. or higher. In general, the components that cause odors often have complex synergistic effects. For example, when component a and component b that hardly feel odor in a simple substance are mixed to form a mixture, the odor is difficult to predict from the simple substance. There is. Although the direct relationship between the lactide content of a molded article made of a polylactic acid polymer and the specific odor is not clear, the inventors of the present inventors have intensively studied and found that the lactide content contained in the molded article is It discovers that the above-mentioned specific odor can be suppressed by setting it as 2 mass% or less, and discloses here.

  From the above viewpoint, the lactide content of the molded article of the present invention is preferably 1.2% by mass or less, more preferably 0.6% by mass or less, and more preferably 0.3% by mass or less.

  As a method for reducing the lactide content in a molded article, a method for reducing and removing a lactic acid oligomer component in a raw material such as a polylactic acid polymer to be used in advance, a method for reducing or removing at the time of molding or processing or after that, etc. Is raised. For example, in the case of a film, a specific example is as follows. At the time of synthesis of raw materials such as a polylactic acid polymer, a method of adjusting the catalyst species and amount, reaction time, temperature, etc., using water or an organic solvent from the raw material Method of removing oligomers, drying temperature and time when using raw materials, method of removing oligomers by adjusting the degree of vacuum, method of adjusting extrusion temperature and residence time during melt film formation, stretching temperature, heat treatment temperature, processing time Or a method of subjecting the film after film formation to a reduced pressure treatment or a heat treatment under an inert gas, a method of extracting using water or an organic solvent, and the like. Preferably, a method of extracting and washing the raw material using water or an organic solvent, a method of adjusting the drying temperature during drying of the raw material to 90 to 120 ° C., a longer drying time, and a higher degree of vacuum, Examples thereof include a method of adjusting the extrusion temperature lower and shorter than the residence time, and a method of performing a heat treatment for a longer time of 10 seconds or more at a higher temperature of 100 ° C. or higher in the film forming process.

  Although there is no restriction | limiting in particular regarding the compounding quantity in the polylactic acid-type molded article of this invention, A polylactic acid resin and (B) component (Poly (meth) acrylate and / or a glass transition temperature are 60 degreeC or more polyvinyl compounds). When the total is 100 parts by mass, polylactic acid resin 99 parts by mass or less and more than 20 parts by mass, and (B) component 1 part by mass or more and less than 80 parts by mass, preferably polylactic acid resin 99 parts by mass or less and more than 50 parts by mass, When the component (B) is 1 part by weight or more and less than 50 parts by weight, it is useful for improving the properties of the polylactic acid resin, and particularly for improving the transparency, mechanical properties and heat resistance of the polylactic acid resin. effective. From the viewpoint of further improvement of the above characteristics, more preferably, the polylactic acid resin is 90 parts by mass or less and more than 60 parts by mass, and the component (B) is 10 parts by mass or more and less than 40 parts by mass, more preferably 85 parts by mass or less of the polylactic acid resin. More than 15 parts and less than 35 parts by weight of component (B).

  One of methods for specifying an accurate blending amount is specification by NMR. For example, in order to specify the blending amount of polylactic acid and polymethyl methacrylate, NMR measurement of 1H nucleus is performed at 55 ° C. in a deuterated chloroform solvent, and a peak derived from polylactic acid (for example, a peak derived from methine group) and polymethyl It can be calculated from the intensity ratio of a peak derived from methacrylate (for example, a peak derived from a methoxy group). If the peak of 1H nucleus cannot be calculated by duplication, the 13C nucleus can be further measured and identified.

When the polylactic acid-based molded article of the present invention is used as, for example, a polylactic acid biaxially stretched film, the transparency is excellent, and a 100 μm-thickness converted haze value is 10% or less, more preferably 7% or less. And particularly preferably 5% or less. Here, the 100 μm-thickness converted haze value refers to a converted value when the film sample whose thickness has been measured in advance is a film having a thickness of 100 μm, but it is 10% or less even in the actual measured value before conversion. It is preferable that The 100 μm-thickness haze value can be obtained by the following formula.
H ₁₀₀ (%) = H × 100 / d
here,
H ₁₀₀ : 100 μm thickness equivalent haze value (%)
H: Actual value of haze (%)
d: Film thickness (μm) of haze measuring section
It is.

  Various particles can be added to the polylactic acid-based molded article of the present invention depending on the purpose and application. The particles to be added are not particularly limited as long as the effects of the present invention are not impaired, and examples thereof include inorganic particles, organic particles, crosslinked polymer particles, and internal particles generated in the polymerization system. Two or more kinds of these particles may be added. From the viewpoint of the mechanical properties of the polylactic acid-based molded article, the amount of such particles added is preferably 0.01 to 10% by mass, and more preferably 0.02 to 1% by mass.

  Moreover, the number average particle diameter of the particle to add becomes like this. Preferably it is 0.001-10 micrometers, More preferably, it is 0.01-2 micrometers. When the number average particle diameter is in such a preferable range, defects of the molded product are hardly generated, and deterioration of transparency and moldability are not caused.

  In the polylactic acid-based molded article of the present invention, additives as necessary within a range not impairing the object and effect of the present invention, for example, flame retardant, heat stabilizer, antioxidant, ultraviolet absorber, antistatic agent, An appropriate amount of a plasticizer, a tackifier, an organic lubricant such as a fatty acid ester or wax, an antifoaming agent such as polysiloxane, or a coloring agent such as a pigment or a dye can be blended.

  Also, thermoplastic resins such as polyacetal, polyethylene, polypropylene, acrylic resin, polyamide, polyphenylene sulfide resin, polyether ether ketone resin, polyester, polysulfone, polyphenylene oxide, polyimide, polyetherimide, phenol resin, melamine resin, polyester resin, At least one of a thermosetting resin such as a silicone resin and an epoxy resin, a soft thermoplastic resin such as an ethylene / glycidyl methacrylate copolymer, a polyester elastomer, a polyamide elastomer, an ethylene / propylene terpolymer, and an ethylene / butene-1 copolymer More seeds can be included.

  Further, when the molded product is used as a sheet or film, the structure may be a single layer, and a new function such as slipperiness, adhesiveness, tackiness, heat resistance, and weather resistance is imparted to the surface. Therefore, it is good also as a laminated structure. In particular, from the viewpoint of further improving heat resistance, it is preferable to have a layer made of poly (meth) acrylate and / or a polyvinyl compound having a glass transition temperature of 60 ° C. or higher as at least one surface as the component (C).

  In addition, since the layer containing the polylactic acid resin is covered with the component (C), the above-described odor peculiar to polylactic acid is also effective.

  There is no particular limitation on the laminated structure of the sheet. For example, when the II layer and the III layer having different compositions of the resin or additive are added to the I layer composed of the polylactic acid resin and the alloy component, the layers are laminated. Examples include two layers of I / II, three layers of II / I / II, II / I / III, and I / II / III. Furthermore, if necessary, it may have a laminated structure of more than three layers, and the lamination thickness ratio of each layer can be arbitrarily set.

  In the present invention, the poly (meth) acrylate used for the component (B) and the component (C), and the polyvinyl compound having a glass transition temperature of 60 ° C. or higher are generally brittle resins and constitute a molded body. When used as a resin, the impact resistance of the molded article may be deteriorated. Therefore, in order to maintain or improve the impact resistance, there is a method of adding an impact resistance improver to poly (meth) acrylate and a polyvinyl compound having a glass transition temperature of 60 ° C. or higher.

  The impact resistance improver referred to in the present invention is not particularly limited as long as it can be used for improving impact resistance of a thermoplastic resin. For example, at least one selected from the following various impact resistance improvers can be used.

  That is, specific examples of impact modifiers include polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-propylene-nonconjugated diene copolymer, ethylene-butene-1 copolymer, various acrylic rubbers, silicones Acrylic rubber, ethylene-acrylic acid copolymer and its alkali metal salt (so-called ionomer), ethylene-glycidyl (meth) acrylate copolymer, ethylene-acrylic acid alkyl ester copolymer (for example, ethylene-ethyl acrylate) Copolymer, ethylene-butyl acrylate copolymer), acid-modified ethylene-propylene copolymer, diene rubber (for example, polybutadiene, polyisoprene, polychloroprene), copolymer of diene and vinyl monomer (for example, styrene- Butadiene random copolymer Styrene-butadiene block copolymer, styrene-butadiene-styrene block copolymer, styrene-isoprene random copolymer, styrene-isoprene block copolymer, styrene-isoprene-styrene block copolymer, and graft copolymer of styrene with polybutadiene. Polymerized, butadiene-acrylonitrile copolymer), polyisobutylene, copolymer of isobutylene and butadiene or isoprene, natural rubber, thiocol rubber, polysulfide rubber, acrylic rubber, silicone rubber, polyurethane rubber, polyether rubber, epi Chlorohydrin rubber, polyester elastomer, polyamide elastomer and the like can be used.

  Furthermore, those having various degrees of crosslinking, those having various microstructures, for example, those having a cis structure, a trans structure, etc., those having a vinyl group, or those having various average particle diameters (in the resin composition) Alternatively, a so-called core-shell type multi-layered polymer composed of a core layer and one or more shell layers covering the core layer, and the adjacent layers composed of different types of polymers can also be used.

  The various (co) polymers mentioned in the above specific examples may be any of random copolymers, block copolymers and graft copolymers, and can be used as the impact resistance improver of the present invention. it can.

  Furthermore, in making these (co) polymers, it is also possible to copolymerize monomers such as other olefins, dienes, aromatic vinyl compounds, acrylic acid, acrylic ester and methacrylic ester. is there.

  Among these impact modifiers, a polymer containing an acrylic unit and a polymer containing a unit having an acid anhydride group and / or a glycidyl group are preferable. Preferable examples of the acrylic unit herein include methyl methacrylate units, methyl acrylate units, ethyl acrylate units and butyl acrylate units. Preferred examples of units having an acid anhydride group or glycidyl group May include maleic anhydride units and glycidyl methacrylate units.

  The impact resistance improver is a so-called core-shell type multi-layer polymer composed of a core layer and one or more shell layers covering the core layer, and adjacent layers are composed of different polymers. It is preferable that the polymer is a multilayer structure polymer containing methyl methacrylate units or methyl acrylate units in the shell layer. Such a multilayer structure polymer preferably contains an acrylic unit, or preferably contains a unit having an acid anhydride group and / or a glycidyl group. Preferred examples of the acrylic unit include a methyl methacrylate unit, an acrylic acid A methyl unit, an ethyl acrylate unit, and a butyl acrylate unit can be mentioned, As a suitable example of a unit which has an acid anhydride group and a glycidyl group, a maleic anhydride unit and a glycidyl methacrylate unit can be mentioned. In particular, the shell layer contains at least one selected from methyl methacrylate units, methyl acrylate units, maleic anhydride units and glycidyl methacrylate units, and includes butyl acrylate units, ethyl hexyl acrylate units, styrene units and butadiene units. A multilayer structure containing at least one selected from the above in the core layer is preferably used.

  Another preferred impact modifier is polyurethane rubber. Here, the polyurethane rubber is a general term for all elastic bodies having a urethane bond, and includes a thermoplastic polyurethane elastomer and a crosslinked polyurethane rubber obtained by crosslinking it. Of these, thermoplastic polyurethane elastomers are preferred. The thermoplastic polyurethane elastomer has at least a hard segment composed of a diisocyanate and a short chain polyol and a soft segment composed of a diisocyanate and a long chain polyol. As the diisocyanate compound constituting the thermoplastic polyurethane elastomer, diphenylmethane diisocyanate, 2,4- and 2,6-tolylene diisocyanate, m- and p-phenylene diisocyanate, hexamethylene diisocyanate and the like are preferably used. As the short-chain polyol component, 1,2-ethanediol, 1,2-propanediol, 1,4-butanediol, butenediol, 1,6-hexanediol, 1,10-decamethylenediol and the like are preferably used. . As the long-chain polyol as the soft segment, polyalkylene adipate, polyalkylene ether and the like are preferable, and polyethylene-butylene adipate, polybutylene adipate, polynonanediol adipate, polytetramethylene glycol and the like are more preferable. Each component can be suitably used as a mixture of one kind or two or more kinds.

  Moreover, it is preferable that the impact resistance improving agent in this invention matches a refractive index with the refractive index of the resin phase to add from a viewpoint of maintaining transparency. For example, when added to a resin phase composed of polylactic acid having a refractive index of 1.45 as the component (A) and polymethyl methacrylate having a refractive index of 1.49 as the component (B), the refractive index is 1.45 to 1.49. Preferably there is. The refractive index is a value measured at 23 ° C. and a wavelength of 589 nm using an Abbe refractometer.

  Since the polylactic acid-based resin composition according to the present invention is excellent in compatibility or miscibility and can be melt-kneaded, it can be processed into various molded products by a method such as injection molding or extrusion molding. The molded product can be used as an injection molded product, an extrusion molded product, a blow molded product, a film, a fiber, a sheet, or the like. These articles can be used for various applications such as electric / electronic parts, building members, automobile parts, and daily necessities.

  Although the molded article of the present invention can be obtained by an existing melt molding method, a sheet will be described below as an example, particularly including a method for reducing the lactide content.

  Sheets can be obtained by existing manufacturing methods. In order to reduce the lactide content of the polylactic acid polymer used in any case, vacuum drying is performed at 90 ° C. to 110 ° C., the degree of vacuum is 10 Torr or less, and the drying time is 6 hours or more. It is preferable. Further, as a preferable method for removing lactide, there may be mentioned a method in which a polylactic acid polymer is immersed in 10 times volume or more of acetone for 24 hours or more, and then the acetone solution is separated and vacuum dried. In the production of the sheet, the polylactic acid polymer composition can be melt-extruded from the slit-shaped die into a sheet shape by a known method, but the temperature of the extruder, polymer piping, die, etc. is preferably 200 ° C. or less. 190 ° C. or lower is more preferable, and 180 ° C. or lower is more preferable. Further, the residence time from when the polylactic acid polymer and the alloying component are melted in the extruder to when they are discharged from the die is preferably 20 minutes or less, more preferably 10 minutes or less, and further preferably 5 minutes or less. It is more preferable that The extruded sheet-like melt is brought into close contact with the casting drum and cooled and solidified to obtain a sheet. In order to minimize the thermal deterioration of the composition and reduce the lactide content, a twin screw extruder is used, and a vent port is provided in the middle of the twin screw extruder. More preferred is a method of removing low molecular weight volatile components such as lactide.

  In addition, the sheet has an additive as necessary, for example, a flame retardant, a heat stabilizer, a light stabilizer, an antioxidant, an anti-coloring agent, an ultraviolet absorber, a charge, as long as the effects of the present invention are not impaired. An appropriate amount of an inhibitor, a plasticizer, a tackifier, an organic lubricant such as a fatty acid ester or wax, an antifoaming agent such as polysiloxane, or a coloring agent such as a pigment or dye can be blended.

  After forming into a sheet, various surface treatments may be applied for the purpose of improving printability, laminate suitability, coating suitability, and the like. Examples of surface treatment methods include corona discharge treatment, plasma treatment, flame treatment, acid treatment, etc., and any method can be used, but continuous treatment is possible, and equipment for existing film forming equipment is used. Corona discharge treatment can be exemplified as the most preferable because of its easy installation and simple processing.

  Furthermore, it is effective to provide a silicone-based coating functional layer mainly on the surface for the purpose of preventing blocking, antistatic, imparting releasability from the mold, and improving scratch resistance. For example, an in-line coating method performed in the sheet manufacturing process or an off-line coating method performed after winding the sheet can be used.

  The thickness of the sheet of the present invention is not particularly limited, and may be an appropriate thickness depending on the performance required according to the application, for example, heat resistance, mechanical strength, transparency, biodegradation speed, price, Usually, it is 5 μm or more and 1 mm or less, and particularly, a range of 20 μm or more and 300 μm or less is preferably selected.

  Hereinafter, the present invention will be described more specifically with reference to examples.

[Evaluation methods]
(1) Weight average molecular weight of polylactic acid Measurement was performed using Waters 2690 manufactured by Japan Waters Co., Ltd., using PMMA as a standard, column temperature of 40 ° C., and chloroform solvent.

(2) Heat of crystal melting of resin composition (J / g)
The crystal melting calorie of the resin composition was obtained by measuring about 5 mg of a sample using a differential scanning calorimeter RDC220 manufactured by Seiko Denshi Kogyo Co., Ltd. under a nitrogen atmosphere at a heating rate of 20 ° C./min.

(3) Lactide content of molded product [%]:
Dissolve the sheet sample in methylene chloride and adjust the concentration to 1 g / 20 ml, then add 60 ml of acetone, and further drop 320 ml of cyclohexane while stirring ultrasonically to form a precipitate / precipitate mainly composed of polylactic acid polymer. This was separated and filtered to prepare a sample solution. This sample solution was gas chromatograph type 5890 (manufactured by Agilent Technologies, detector: FID type), column: DB-17MS type (manufactured by J & W), column temperature: 50 to 320 ° C., 25 ° C./min, carrier gas: Analysis was performed under the He condition, and a calibration curve was prepared using a sample solution of lactide alone, the concentration of which was changed in advance, and thereby the lactide amount (%) was determined.

(4) Structural Period of Resin Composition Using a light scattering apparatus DYNA-3000 manufactured by Otsuka Electronics Co., Ltd., a structural period Λm (μm) was calculated for a sheet sample having a thickness of 100 μm according to the following formula.
Λm = (λ / 2) / sin (θm / 2)
here,
λ: Wavelength of scattered light in the scatterer (μm)
θm: a scattering angle giving a scattering maximum.
In Tables 1 to 3, “−” was written when the structural period was 0.01 μm or less.

(5) Mechanical properties of resin composition A sheet sample was cut into length x width = 50 mm x 10 mm, and the distance between chucks was 20 mm using Tensilon UTA-4 manufactured by Orientec in an environment of 23 ° C and 50% RH. The tensile strength and tensile elongation were measured at a tensile speed of 10 mm / min.

(6) 100 μm thickness converted haze value As a transparency index of the sheet sample, the haze value of the sheet sample whose thickness was measured in advance was measured using a haze meter HGM-2DP type (manufactured by Suga Test Instruments Co., Ltd.). The measurement was performed 5 times per level, and a 100 μm-thickness converted haze value (%) was obtained as a conversion value when the thickness was set to 100 μm from the average value of the five measurements. The conversion formula is as follows.
H ₁₀₀ (%) = H × 100 / d
here,
H ₁₀₀ : 100 μm thickness equivalent haze value (%)
H: Measured value (%) of haze of sheet sample
d: Sheet sample thickness (μm) of haze measurement section
It is.

(7) Sheet Formability A sheet sample is vacuum formed (straight formed) (preheating: 80 ° C. for 20 seconds (Examples 1 to 3, 5 to 7, Comparative Examples 1 to 5) or 90 ° C. for 20 seconds (Example 4). 8-14) or 110 ° C. for 20 seconds (Examples 15 and 16)), and the moldability was evaluated according to the following criteria. If it is (circle) and (triangle | delta), it is suitable as what satisfies the invention of this application.
○: There is no molding unevenness and good moldability.
(Triangle | delta): Although a molding nonuniformity is seen in part, it is a level which does not have a problem in use.
X: Level at which molding unevenness is seen everywhere or cannot be used as a molded product.

(8) Thermal deformation temperature of the molded product The molded product prepared in (7) is set at a set temperature of 55 ° C, 60 ° C, 65 ° C with only its own weight applied without applying external force such as tension and load. , 70 ° C., 75 ° C., 80 ° C., 85 ° C., and 90 ° C., respectively, for 2 minutes. By observing the molded product after the elapse of 2 minutes, it was confirmed how much the molded product put in the oven at a temperature higher than that was deformed.

(9) Odor after dry heat treatment:
Put 10g of sheet sample into a glass petri dish, cover the glass, heat-treat in a 120 ° C hot air oven for 30 minutes, then take out the petri dish, and evaluate the presence or absence of odor immediately after removing the lid on the following criteria did. If it is (circle) and (triangle | delta), it is suitable as what satisfies the invention of this application.
○: Randomly extracted 7 out of 10 people do not feel odor.
(Triangle | delta): Five or more out of ten people extracted at random do not feel an odor.
X: Other than the above.

(10) Transparency at the time of heating As a transparency index at the time of heating the sheet sample, a sheet sample heated for 24 hours in a hot air oven set at 80 ° C. The value (%) was determined.

(11) Impact resistance of the sheet Using a Toyo Seiki impact tester with a 1/2 inch diameter impact part made of brass, the sheet sample was pressed with a clamp, and the impact resistance of the sheet sample (J / mm) Was measured. Ten samples were prepared, the impact surface was changed, and five samples were measured, and the average value was evaluated.

The resins and additives used are as follows.
PLA-1: Polylactic acid (poly-L lactic acid resin having a D-form content of 1.2% and a PMMA equivalent weight average molecular weight of 160,000)
PLA-2: Polylactic acid (poly L lactic acid resin having a D-form content of 1.4% and a weight average molecular weight in terms of PMMA of 70,000)
PLA-3: Polylactic acid (poly L lactic acid resin having a D-form content of 0.9% and a PMMA equivalent weight average molecular weight of 40,000)
PMMA-1: Polymethylmethacrylate (manufactured by Sumitomo Chemical Co., Ltd. “SUMIPEX” MGSS fluidity: 10 g / 10 min)
PMMA-2: Polymethylmethacrylate (manufactured by Sumitomo Chemical Co., Ltd. “SUMIPEX” MG5 fluidity: 5 g / 10 min)
PMMA-3: Polymethylmethacrylate (manufactured by Sumitomo Chemical Co., Ltd. “SUMIPEX” MHF fluidity: 2 g / 10 min)
PMMA-4: Polymethylmethacrylate (manufactured by Sumitomo Chemical Co., Ltd. “SUMIPEX” LG fluidity: 10 g / 10 min)
PMMA-5: Polymethylmethacrylate (“SUMIPEX” LG21, manufactured by Sumitomo Chemical Co., Ltd., fluidity: 21 g / 10 min)
PMMA-6: Polymethylmethacrylate containing impact modifier (Sumitomo Chemical Co., Ltd. “Sumipex” HT50Y fluidity: 14 g / 10 min)
PVPh: Polyvinylphenol (Glass transition temperature: 146 ° C. “MARUKALYNCUR” S-2P manufactured by Maruzen Petrochemical Co., Ltd.)
PS: Polystyrene (Glass transition temperature: 90 ° C. “GPPS679” manufactured by A & M Polystyrene)
PVAc: polyvinyl acetate (glass transition temperature: 30 ° C. Aldrich reagent)
EBLA: Ethylene bis lauric acid amide (“Sripacks L” manufactured by Nippon Kasei Co., Ltd.)
R-1: Acrylic impact resistance improver ("Maybrene" W-450A manufactured by Mitsubishi Rayon Co., Ltd., refractive index: 1.472).

Example 1
The bent-type two-way direction set to 210 ° C. with 90 parts by mass of the PLA-1 dried at 120 ° C. for 5 hours under a high vacuum of 10 torr and 10 parts by mass of the PMMA-1 dried at 90 ° C. for 6 hours. It is fed to a shaft extruder (2 vents (vacuum level: 10 torr), L / D = 45), led to a T-die die set at a die temperature of 220 ° C., and extruded into a sheet shape. It was made to adhere and to cool and solidify, and it was set as the unstretched sheet of thickness 100 micrometers. The unstretched sheet can be prepared stably, and the physical properties of the obtained sheet are shown in Table 1.

  Separately, when the sheet was straight-formed, the moldability was also good. Furthermore, the heat distortion temperature of the molded product was also higher than that of polylactic acid alone.

  Furthermore, the odor suppressing effect after the dry heat treatment of the sheet was relatively excellent.

(Example 2)
An unstretched sheet was obtained and the sheet was molded in the same manner as in Example 1 except that the PLA-1 amount was 80 parts by mass and the PMMA-1 amount was 20 parts by mass. The evaluation results of the obtained sheet and molded product are shown in Table 1.

  Compared with Example 1, since the ratio of the PMMA component increased, the heat deformation temperature was particularly improved.

(Example 3)
Vent-type two-way direction set to 210 ° C. with 80 parts by mass of PLA-1 dried under high vacuum of 10 torr at 120 ° C. and 20 parts by mass of PMMA-1 dried at 90 ° C. for 6 hours. It is fed to a shaft extruder (2 vents (degree of vacuum: 3 torr), L / D = 45), led to a T die die set at a die temperature of 220 ° C., and extruded into a sheet shape. It was made to adhere and to cool and solidify, and it was set as the unstretched sheet of thickness 100 micrometers. The unstretched sheet can be prepared stably, and the physical properties of the obtained sheet are shown in Table 1.

  Separately, when the sheet was straight-formed, the moldability was also good. Further, the heat distortion temperature of the molded product was higher than that of Example 1.

  Furthermore, the odor suppression effect after the dry heat treatment of the sheet was further improved compared to Example 2 because the lactide content could be suppressed by increasing the degree of vacuum of the vent.

Example 4
An unstretched sheet was obtained in the same manner as in Example 1 except that the PLA-1 amount was 50 parts by mass and the PMMA-1 amount was 50 parts by mass, and the sheet was molded. The evaluation results of the obtained sheet and molded product are shown in Table 1.

  Compared with Example 1, since the ratio of the PMMA component increased, the heat deformation temperature was particularly improved.

(Example 5)
An unstretched sheet was obtained in the same manner as in Example 2 except that PMMA-1 was changed to PMMA-2. Table 1 shows the physical properties of the obtained sheet.

  Separately, when the sheet was straight-formed, the formability was good. When the structure period was 0.05 μm, the transparency was slightly deteriorated but at a practical level.

  Further, the heat distortion temperature of the molded product was higher than that of Example 1, and the odor suppressing effect after the dry heat treatment of the sheet was relatively excellent.

(Example 6)
An unstretched sheet was obtained in the same manner as in Example 2 except that PMMA-1 was changed to PMMA-3. Table 1 shows the physical properties of the obtained sheet.

  Separately, when the sheet was straight-formed, the formability was also good. Although the structural period was 3.2 μm, the transparency was slightly deteriorated but at a practical level.

  Further, the heat distortion temperature of the molded product was higher than that of Example 1, and the odor suppressing effect after the dry heat treatment of the sheet was relatively excellent.

(Example 7)
An unstretched sheet was obtained and the sheet was molded in the same manner as in Example 2 except that PLA-1 was changed to PLA-2. The evaluation results of the obtained sheet and molded product are shown in Table 1.

  Due to the decrease in the molecular weight of the polylactic acid resin, although the thermal deformation temperature was decreased as compared with Example 2, it was at a level causing no practical problem.

(Example 8)
Vented different direction biaxial extrusion set at 210 ° C. by 90 parts by mass of PLA-1 dried under high vacuum of 10 torr at 120 ° C. and 10 parts by mass of PVPh dried at 130 ° C. for 6 hours. Machine (2 vent sections (degree of vacuum: 10 torr), L / D = 45), led to a T-die base set at a base temperature of 220 ° C., extruded into a sheet shape, and brought into close contact with the casting drum by electrostatic application method It cooled and solidified and it was set as the 100-micrometer-thick unstretched sheet. The unstretched sheet can be prepared stably, and the physical properties of the obtained sheet are shown in Table 1.

  Separately, when the sheet was straight-formed, the moldability was also good. Furthermore, the heat distortion temperature of the molded product was also higher than that of polylactic acid alone.

  Furthermore, the odor suppressing effect after the dry heat treatment of the sheet was relatively excellent.

Example 9
An unstretched sheet was obtained and the sheet was molded in the same manner as in Example 8 except that the PLA-1 amount was 80 parts by mass and the PVPh amount was 20 parts by mass. Table 1 shows the evaluation results of the obtained sheet and molded product.

  Since the ratio of the PVPh component was increased as compared with Example 8, an improvement in the heat distortion temperature was particularly observed.

(Example 10)
Vent-type opposite-direction biaxial extrusion set at 210 ° C. with 80 parts by mass of PLA-1 dried at 120 ° C. for 5 hours under a high vacuum of 10 torr and 20 parts by mass of PVPh dried at 130 ° C. for 6 hours. Machine (2 vent parts (vacuum level: 3 torr), L / D = 45), led to a T die die set at a die temperature of 220 ° C., extruded into a sheet shape, and brought into close contact with the casting drum by electrostatic application method It cooled and solidified and it was set as the 100-micrometer-thick unstretched sheet. The unstretched sheet can be prepared stably, and the physical properties of the obtained sheet are shown in Table 1.

  Separately, when the sheet was straight-formed, the moldability was also good. Further, the heat distortion temperature of the molded product was higher than that in Example 8.

  Further, the effect of suppressing the odor after the dry heat treatment of the sheet was further improved as compared with Example 9 because the lactide content could be suppressed by increasing the degree of vacuum of the vent.

(Example 11)
An unstretched sheet was obtained and molded in the same manner as in Example 8 except that the PLA-1 amount was 70 parts by mass and the PVPh amount was 30 parts by mass. Table 1 shows the evaluation results of the obtained sheet and molded product.

  Compared to Example 8, particularly an improvement in heat distortion temperature was observed.

(Example 12)
Vent-type different-direction biaxial extrusion set at 210 ° C. with 90 parts by mass of PLA-1 dried at 120 ° C. for 5 hours under a high vacuum of 10 torr and 10 parts by mass of PS dried at 80 ° C. for 6 hours. Machine (2 vent sections (degree of vacuum: 10 torr), L / D = 45), led to a T-die base set at a base temperature of 220 ° C., extruded into a sheet shape, and brought into close contact with the casting drum by electrostatic application method It cooled and solidified and it was set as the 100-micrometer-thick unstretched sheet. The unstretched sheet can be prepared stably, and the physical properties of the obtained sheet are shown in Table 1.

  Separately, when the sheet was straight-formed, a decrease in formability was slightly observed as compared with Example 1, but it was in a practically no problem range. Further, the heat distortion temperature of the molded product was higher than that of Example 1 because the ratio of the PVPh component increased.

  Furthermore, the odor suppressing effect after the dry heat treatment of the sheet was relatively excellent.

(Example 13)
50 parts by mass of a 99/1 mass% blend of PLA-1 and crystal nucleating agent EBLA dried under high vacuum of 10 torr at 120 ° C. for 5 hours, and PMMA-4 50 dried at 80 ° C. for 6 hours. T-die die set at a die temperature of 220 ° C. by feeding the mass part to a vented different-direction twin screw extruder set at 210 ° C. (two vent parts (vacuum degree: 10 torr), L / D = 45) Then, the sheet was extruded into a sheet shape, adhered to a casting drum by an electrostatic application method, and solidified by cooling to obtain an unstretched sheet having a thickness of 100 μm. The unstretched sheet can be prepared stably, and the physical properties of the obtained sheet are shown in Table 3.

  Separately, when the sheet was straight-formed, the moldability was also good. Further, the transparency of the sheet upon heating was improved by adding a crystal nucleating agent.

(Example 14)
50 parts by mass of PLA-1 dried at 120 ° C. for 5 hours under a high vacuum of 10 torr, 85/15% by mass of PMMA-4 and impact modifier R-1 dried at 80 ° C. for 6 hours 50 parts by mass of the blended product is fed to a vent type different-direction twin screw extruder set at 210 ° C. (2 vents (vacuum degree: 10 torr), L / D = 45) and set to a base temperature of 220 ° C. The sheet was guided to the T die die and extruded into a sheet shape. The sheet was brought into close contact with the casting drum by an electrostatic application method and solidified by cooling to obtain an unstretched sheet having a thickness of 100 μm. The unstretched sheet can be prepared stably, and the physical properties of the obtained sheet are shown in Table 3.

  Separately, when the sheet was straight-formed, the moldability was also good. Furthermore, the impact resistance of the sheet was improved by adding the impact resistance improver R-1.

(Example 15)
For layer I, 90 parts by mass of a 99/1 mass% blend of the PLA-1 and the crystal nucleating agent EBLA dried under high vacuum of 10 torr at 120 ° C. for 5 hours, and dried at 80 ° C. for 6 hours. 10 parts by mass of 85/15% by mass blend of PMMA-4 and impact modifier R-1 and PMMA-6 dried for 6 hours at 80 ° C. for layer II Were supplied to separate vent type different-direction twin screw extruders (2 vents (vacuum degree: 10 torr), L / D = 45) and co-extruded from a T-die die set at a base temperature of 220 ° C. By an application method, it was brought into close contact with a casting drum cooled to 10 ° C. to be cooled and solidified to obtain an unstretched sheet having a layer II: layer I: layer II of 1: 3: 1 and a thickness of 100 μm. The unstretched sheet can be prepared stably, and the physical properties of the obtained sheet are shown in Table 3.

  Separately, when the sheet was straight-formed, the moldability was also good.

  The heat resistance of the sheet was improved by laminating the PMMA component. Further, the transparency during heating of the sheet becomes favorable by adding a crystal nucleating agent, and the impact resistance of the sheet becomes favorable by adding an impact resistance improving agent R-1. It was. Furthermore, the odor suppression effect after the dry heat treatment of the sheet was excellent by using the PMMA component for the surface layer.

(Example 16)
For layer I, 90 parts by mass of a 99/1 mass% blend of the PLA-1 and the crystal nucleating agent EBLA dried under high vacuum of 10 torr at 120 ° C. for 5 hours, and dried at 80 ° C. for 6 hours. 10 parts by mass of 85/15% by weight blend of PMMA-4 and impact modifier R-1 and layer II, dried for 6 hours at 80 ° C. and PMMA-5 and improved impact resistance The 85/15 mass% blend of the agent R-1 is supplied to each independent vent type different-direction biaxial extruder (2 vent portions (vacuum degree: 10 torr), L / D = 45). Co-extruded from a T-die die set at a base temperature of 220 ° C., adhered to a casting drum cooled to 10 ° C. by electrostatic application, and solidified by cooling. Layer II: Layer I: Layer II was 1: 8: 1. An unstretched sheet having a thickness of 100 μm was obtained. The unstretched sheet can be prepared stably, and the physical properties of the obtained sheet are shown in Table 3.

Separately, when the sheet was straight-formed, the formability was also good. In addition, by adding a crystal nucleating agent, the transparency of the sheet after heating becomes good, and by using the PMMA component and the impact modifier component in the surface layer, the odor after the dry heat treatment is also a good result. there were. Furthermore, the impact resistance of the sheet was improved by adding the impact modifier R-1 (Comparative Example 1).
Except that the alloying component was not blended, an unstretched sheet was formed in the same manner as in Example 1 to obtain a sample for comparison with the alloying component mixed system.

(Comparative Example 2)
Except for changing PLA-1 to PLA-3, an unstretched sheet was formed in the same manner as in Example 2. However, since the molecular weight of polylactic acid was outside the scope of the claims, it should be stably formed into a sheet. I could not. Table 2 shows the evaluation results of the samples that were partially collected.

(Comparative Example 3)
An unstretched sheet was obtained and the sheet was molded in the same manner as in Example 9 except that PVPh was changed to PVAc. Table 2 shows the evaluation results of the obtained sheet and molded product.
Compared to polylactic acid alone (Comparative Example 1), the heat distortion temperature further decreased.

(Comparative Example 4)
Vent-type two-way direction set to 210 ° C. with 80 parts by mass of PLA-1 dried under high vacuum of 10 torr at 120 ° C. and 20 parts by mass of PMMA-1 dried at 90 ° C. for 6 hours. It is fed to a shaft extruder (2 vents (degree of vacuum: 20 torr), L / D = 45), led to a T die die set at a die temperature of 220 ° C., extruded into a sheet shape, and applied to a casting drum by electrostatic application. After closely contacting and solidifying by cooling, heat treatment was performed for 3 minutes at 140 ° C. to obtain an unstretched sheet.

  Although the odor suppressing effect after the dry heat treatment of the sheet was excellent due to the heat treatment effect, the heat of crystal melting of the sheet exceeded 10 J / g, and the formability was poor.

(Comparative Example 5)
Vent-type two-way direction set to 210 ° C. with 80 parts by mass of PLA-1 dried under high vacuum of 10 torr at 120 ° C. and 20 parts by mass of PMMA-1 dried at 90 ° C. for 6 hours. It is fed to a shaft extruder (no vent, L / D = 45), led to a T die die set at a die temperature of 220 ° C., extruded into a sheet shape, closely contacted with a casting drum by an electrostatic application method, and solidified by cooling, thickness 100 μm This was an unstretched sheet. The unstretched sheet can be formed stably, and the physical properties of the obtained sheet are shown in Table 2.

  Since the lactide content of the sheet exceeded 2% by mass, the odor suppressing effect after the dry heat treatment was not observed.

  The present invention can be applied to various packaging materials, various industrial materials, films for various industrial materials, and the like. Specifically, it can be preferably used for molded products such as various shape holders such as blister packs, containers such as food trays and beverage cups, and display bottles for beverage vending machines. However, it is not limited to these.

Claims (10)

(A) a polylactic acid resin having a weight average molecular weight of 50,000 or more as a component;
(B) Poly (meth) acrylate as a component and / or a polyvinyl compound having a glass transition temperature of 60 ° C. or higher,
A molded product made of a polylactic acid resin composition, wherein the molded product has a heat of crystal melting (ΔHm) of 10 J / g or less in DSC temperature rise measurement, and contains lactide in the molded product Molded product whose amount is 2% by mass or less.   The molded article according to claim 1, wherein the polylactic acid resin composition has a structural period of 3 μm or less.   The molded article according to claim 2, wherein the structural period of the polylactic acid resin composition is 0.01 µm or less.   The molded article according to any one of claims 1 to 3, wherein the polylactic acid resin composition has a haze value in terms of 100 µm thickness of 10% or less.   The polylactic acid resin composition is in sheet form, and has a layer made of poly (meth) acrylate as a component (C) and / or a polyvinyl compound having a glass transition temperature of 60 ° C or higher on at least one side. The molded product according to any one of the above.   The molded article according to any one of claims 1 to 5, wherein the poly (meth) acrylate of the component (B) and / or the component (C) is polymethyl methacrylate.   The molded article according to claim 6, wherein polymethyl methacrylate having a fluidity at 230 ° C. measured in accordance with JIS K7210 of 2 g / 10 min or more is used.   The molded product according to any one of claims 1 to 7, wherein the polyvinyl compound of component (B) and / or component (C) is polyvinylphenol.   The molded article according to any one of claims 1 to 8, wherein an impact resistance improver is further added to the component (B) and / or the component (C).   The molded article according to any one of claims 1 to 9, wherein a crystal nucleating agent is further added to the component (A).