TW201534655A - Polylactic acid resin sheet for thermoforming - Google Patents

Abstract

Provided is a sheet for thermoforming which is formed from a polylactic acid resin composition prepared by adding 0.5-3.5 parts by mass of a plasticizer and 0.15-0.45 parts by mass of an organic nucleating agent to 100 parts by mass of a polylactic acid resin. Also provided are a production method for the sheet, a molded article obtained by forming the sheet, a production method for the molded article, and a method for machining the sheet. The sheet for thermoforming according to the present invention exhibits excellent thermoforming properties, and thus is suitable for various uses, including use in food containers and in trays for industrial components, and use as a packaging material for household goods and appliances.

Description

Polylactic acid resin sheet for thermoforming

The present invention relates to a polylactic acid resin sheet for thermoforming. More specifically, the present invention relates to a sheet comprising a polylactic acid resin composition which can be preferably used for a molded article such as a daily necessities, cosmetics, home electric appliances, or the like, and a method for producing the same, and the sheet is formed by molding A molded body, a method for producing the same, and a method for processing the sheet.

Polylactic acid resin is currently expected to be used because it is a raw material, and L-lactic acid is produced by using corn, potato, etc., and is produced by a fermentation process, so that it is relatively inexpensive; Therefore, the amount of carbon dioxide emission is extremely small; and the rigidity as a resin property is strong and the transparency is high.

For example, Patent Document 1 discloses an organic crystal nucleating agent (B) comprising an aliphatic carboxyguanamine containing 100 parts by weight of a lactic acid-based polymer (A) and having a guanamine bond. 3 parts by weight and a sheet of the lactic acid-based polymer composition of 0.1 to 7 parts by weight of the crystallization accelerator (C) are thermoformed at a temperature of 60 to 130 ° C, and transparency and heat resistance can be obtained with excellent production efficiency. The formed body.

Further, Patent Document 2 describes that by combining a specific organic crystal nucleating agent and a specific nonionic surfactant in addition to a plasticizer in a polylactic acid resin, transparency can be maintained and thermoforming can be simultaneously achieved. The shape and crystallization are obtained, that is, a polylactic acid resin composition in which thermoformability is remarkably improved.

[Previous Technical Literature] [Patent Literature]

Patent Document 1: International Publication No. 2006/121056

Patent Document 2: Japanese Patent Laid-Open Publication No. 2012-180512

The present invention relates to the following [1] to [7].

[1] A sheet for thermoforming comprising polylactic acid containing 0.5 to 3.5 parts by mass of a plasticizer and 100 to 0.45 parts by mass of an organic crystal nucleating agent in 100 parts by mass of the polylactic acid resin. Resin composition.

[2] A method for producing a sheet for thermoforming, comprising the following steps (A) and (B): Step (A): an extruder having a temperature of 170 to 240 ° C is used in a polylactic acid resin in relation to The polylactic acid resin composition containing 0.5 to 3.5 parts by mass of the plasticizer and 0.15 to 0.45 parts by mass of the organic crystal nucleating agent is extruded to prepare a sheet molded article; and the step (B): The sheet molded article obtained in the step (A) was cooled by contact with a cooling roll having a temperature of less than 40 °C.

[3] A method for producing a hot formed body, comprising the following steps (1) and (2): Step (1): heating the sheet for thermoforming as in the above [1] to a glass transition temperature of the sheet ( Tg) is above the temperature range of the melting point (Tm); Step (2): The sheet obtained by the step (1) is thermoformed using a mold having a mold temperature of 60 to 140 °C.

[4] A molded article obtained by vacuum forming or pressure forming a sheet for thermoforming according to [1] above.

[5] A secondary processing method of a sheet, characterized in that the sheet for thermoforming according to the above [1] is subjected to vacuum forming or pressure forming.

[6] A packaging material comprising the formed body of the above [4].

[7] A sheet for thermoforming, which has a glass transition temperature of 50 to 60 ° C, a half crystallization time of 5 to 27 seconds, and a haze value of the obtained thermoformed body of 0.1 to 8.0%.

1‧‧‧Sampling surface

Fig. 1(a) is a stacked view (cross-sectional view) of a molding die used in the embodiment.

Fig. 1(b) is a vacuum molded product (cup shape) as a molding die used in the examples.

If the previous polylactic acid resin is used as a resin that can replace various plastics, further improvement is required. In other words, it is expected that transparency can be maintained in thermoforming of polylactic acid resin, and the temperature range of thermoforming can be wide, and a sufficient crystallization rate can be obtained, that is, sufficient thermoformability can be achieved (formation and crystallization can be simultaneously achieved). A polylactic acid resin sheet for thermoforming, which has a wide temperature range. Furthermore, in general, the produced polylactic acid resin sheet for thermoforming is sold as a raw material roll (a roll of a resin sheet), but it is stored under the conditions before sale or molding. There is a case where the hot formability is deteriorated, and in particular, the hot formability is deteriorated due to storage under a relatively high temperature (30 to 40 ° C) in the storage in a summer warehouse, which is a serious problem. .

The present invention relates to a sheet for thermoforming comprising a polylactic acid resin composition which is excellent in thermoformability even after storage in such a summer, and a molded article obtained by molding the sheet and a method for producing the same And the processing method of the sheet.

The sheet for thermoforming of the present invention is excellent in thermoformability, and in particular, it is excellent in thermoformability even after storage at a high temperature, and therefore, a molded article having a good appearance can be provided extremely easily. In addition, since the thermoformability is excellent even after storage at a high temperature, the sheet for thermoforming of the present invention exhibits an excellent effect of excellent storage stability.

The inventors of the present invention conducted intensive studies in view of such circumstances, and as a result, found that by combining a specific amount of a plasticizer with a specific amount of an organic crystal nucleating agent in a polylactic acid resin, heat after storage at a high temperature can be obtained. The sheet for thermoforming, which is also excellent in moldability, completes the present invention.

One of the characteristics of the sheet for thermoforming of the present invention is that it comprises a polylactic acid resin composition containing a specific additive in addition to the polylactic acid resin, that is, A specific amount of plasticizer and a specific amount of an organic crystal nucleating agent.

[Polylactic acid resin composition] [Polylactic acid resin]

Examples of the polylactic acid resin include Nature Works PLA/NW3001D manufactured by Nature Works, NW4032D, or commercially available polylactic acid resins such as Eco Plastics U'z S-09, S-12, and S-17 manufactured by Toyota Motor Corporation. Further, a polylactic acid resin synthesized from lactic acid or lactide is exemplified. From the viewpoint of thermoformability and transparency after storage at a high temperature, a polylactic acid resin having an optical purity of 90% or more is preferable, and for example, Nature Works, which has a relatively high relative molecular weight and a high optical purity, is preferable. Polylactic acid resin (NW4032D, etc.) manufactured.

Further, in the present invention, the polylactic acid resin may be used as a polylactic acid resin, and may contain different isomers as a main component, from the viewpoint of thermoformability and transparency after storage of the polylactic acid resin composition at a high temperature. Two types of polylactic acid obtained by the lactic acid component are sterically misaligned polylactic acid resins.

Further, the polylactic acid resin in the present invention may contain a biodegradable polyester resin other than a polylactic acid resin or a non-biodegradable resin such as polypropylene in the form of a polymer alloy obtained by blending with a polylactic acid resin. In addition, in the present specification, the term "biodegradability" refers to a property which can be decomposed into a low molecular compound by microorganisms in nature, and specifically means that it is controlled based on JIS K6953 (ISO14855). Biodegradability of aerobic and ultimate biodegradability and disintegration test under oxygen composting conditions.

The content of the polylactic acid resin in the polylactic acid resin composition is preferably 50% by mass or more, more preferably 70% by mass or more, and still more preferably 90% by mass or more.

[Plasticizer]

The plasticizer used in the present invention is not particularly limited, and examples thereof include a plasticizer for a general biodegradable resin. Among them, the thermoformability and transparency after storage at high temperatures From the viewpoint of the nature, it is preferably a compound having two or more ester groups in the molecule, more preferably having two or more ester groups in the molecule, and the average addition mole number per one molecule of ethylene oxide is higher. Preferably, the compound is 2 to 9, more preferably 3 to 9. As such a compound, an ester of a polyvalent carboxylic acid and a monool or a (poly)oxyalkylene adduct thereof, and a monocarboxylic acid or a polycarboxylic acid and a polyhydric alcohol or a (poly)oxyalkylene group thereof may be mentioned. The ester of the product, and the like.

Specifically, for example, a plasticizer described in JP-A-2008-174718 and JP-A-2008-115372 can be cited. Among them, it is preferred to suitably use an ester selected from an average of 3 to 6 moles of ethylene oxide of acetic acid and glycerin (each hydroxyl group is added to 1 to 2 moles of ethylene oxide), acetic acid and epoxy B. The average addition of alkane is an ester of polyethylene glycol having a molar number of 4 to 6, an average addition of succinic acid to ethylene oxide, and a polyethylene glycol monomethyl ether having a molar number of 2 to 3 (each hydroxyl group) Addition of 2~3 moles of ethylene oxide) ester, adipic acid and diethylene glycol monomethyl ether ester, adipic acid and 1-butanol ester, ethyl citrate and 1-butanol ester And one or more selected from the group consisting of esters of 1,3,6-hexanetricarboxylic acid and diethylene glycol monomethyl ether, more preferably suitably selected from the group consisting of succinic acid and ethylene oxide. One of a group consisting of a polyethylene glycol monomethyl ether of 2 to 3, an ester of adipic acid and diethylene glycol monomethyl ether, an ester of acetamidine citrate and 1-butanol the above.

The content of the plasticizer is 0.5 parts by mass or more, preferably 1 part by mass, per 100 parts by mass of the polylactic acid resin, from the viewpoint of shortening the thermoformability, the transparency, and the half crystallization time of the sheet for thermoforming. In the above, the amount of the glass transition temperature of the sheet for thermoforming, the transparency, and the thermoformability after storage at a high temperature are preferably 3.5 parts by mass or less, preferably 3.5 parts by mass or more. 3 parts by mass or less, more preferably 2.5 parts by mass or less.

[Organic Crystal Nucleating Agent]

The organic crystallization nucleating agent used in the present invention is not particularly limited, and examples thereof include an organic crystallization nucleating agent for a general biodegradable resin. Among them, in terms of transparency and thermoformability after storage at a high temperature, it is preferred to have an organic crystal nucleating agent molecule. A total of two or more aliphatic compounds selected from the group consisting of ester groups, hydroxyl groups, and guanamine groups, or two or more groups. For example, an alkyl diamine amide, an alkyl bishydroxy fatty decylamine, etc. are mentioned. Among them, from the viewpoints of transparency of the sheet for thermoforming, shortening of the half crystallization time, and thermoformability after storage at a high temperature, it is preferred to have one or more hydroxyl groups and one or more ester groups. Further, the aliphatic compound of the guanamine group is more preferably an aliphatic compound having two or more hydroxyl groups and having one or more ester groups or sulfonium groups, and more preferably two or more hydroxyl groups and two or more. An ester or guanamine-based aliphatic compound.

The aliphatic compound having a hydroxyl group and a guanamine group in the organic crystal nucleating agent molecule is preferably an aliphatic guanamine having a hydroxyl group, and specific examples thereof include a hydroxyl group such as 12-hydroxystearic acid monoethanolamine. The fatty acid monodecylamine, methylenebis 12-hydroxystearylamine, exoethylbis 12-hydroxystearylamine, hexamethylenebis 12-hydroxystearamide, and the like are hydroxy fatty acid bis-guanamine.

The content of the organic crystal nucleating agent is 100 parts by mass based on 100 parts by mass of the polylactic acid resin, from the viewpoint of thermoformability, transparency, shortening of the half crystallization time, and thermoformability after storage at a high temperature. 0.15 parts by mass or more, preferably 0.2 parts by mass or more, more preferably 0.3 parts by mass or more, still more preferably 0.33 parts by mass or more. In addition, from the viewpoint of thermoformability of the sheet for thermoforming, shortening of the half crystallization time, and thermoformability after storage at a high temperature, it is 0.45 parts by mass or less, preferably 0.4 parts by mass or less, more preferably It is 0.38 parts by mass or less.

Further, in the present invention, it is preferred to use two kinds of aliphatic decylamines having different structures as organic nucleating agents. Specific examples thereof include an aliphatic decylamine having a hydroxyl group and having two or more guanamine bonds, and an aliphatic guanamine having no hydroxyl group and having two or more guanamine bonds. By using the above two kinds of aliphatic guanamines, the nucleating agent forms an association structure and is stabilized, and exhibits an effect of excellent thermoformability even after storage at a high temperature. Furthermore, in the present specification, an aliphatic guanamine having a hydroxyl group and having two or more guanamine bonds may also be used. The aliphatic decylamine having a hydroxyl group and having two or more guanamine bonds is described as "an aliphatic guanamine containing no hydroxyl group".

The aliphatic guanamine containing a hydroxyl group is preferably an aliphatic compound having one or more hydroxyl groups and having two or more guanamine bonds, more preferably having two or more hydroxyl groups and having two or more guanamine bonds. An aliphatic compound. The compound may, for example, be a hydroxy fatty acid bis-guanamine or the like. Specifically, for example, methylenebis 12-hydroxystearylamine, exoethylbis 12-hydroxystearylamine, hexamethylene double 12 may be used. - Hydroxystearylamine, phenyldimethylbis 12-hydroxystearylamine.

Examples of the aliphatic guanamine which does not contain a hydroxyl group include a fatty acid bis-guanamine which does not have a hydroxyl group, and specific examples thereof include, for example, ethyl bis-stearylamine, ethyl oleate, and ethyl bis. Laurel.

The content of the aliphatic guanamine containing a hydroxyl group is not particularly limited as long as the total content of the organic nucleating agent is 0.15 parts by mass or more and 0.45 parts by mass or less, but the half-crystallization time of the sheet for thermoforming is shortened. From the viewpoint of the excellent thermoformability after storage at a high temperature, it is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, based on 100 parts by mass of the polylactic acid resin, and the viewpoint of transparency is obtained. In general, it is preferably 0.40 parts by mass or less.

The content of the aliphatic guanamine containing no hydroxyl group is not particularly limited as long as the total content of the organic nucleating agent is 0.15 parts by mass or more and 0.45 parts by mass or less, but the half crystallization time of the sheet for thermoforming is From the viewpoint of the shortening of the viewpoint and the excellent thermoformability after storage at a high temperature, it is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, based on 100 parts by mass of the polylactic acid resin, and transparency is obtained. From the viewpoint, it is preferably 0.40 parts by mass or less.

Further, from the viewpoint of shortening the half-crystallization time of the sheet for thermoforming and the thermoformability after storage at a high temperature, the aliphatic guanamine containing a hydroxyl group and the aliphatic guanamine containing no hydroxyl group are used. Mass ratio (aliphatic steroid containing hydroxyl group / aliphatic group without hydroxyl group) The guanamine is preferably from 0.1 to 10, more preferably from 0.2 to 5.0, still more preferably from 0.3 to 4.0, still more preferably from 0.5 to 2.0, still more preferably from 0.6 to 1.5.

In the present invention, the organic nucleating agent other than the aliphatic guanamine containing a hydroxyl group and the aliphatic guanamine containing no hydroxyl group is not particularly limited, but the half crystallization time of the sheet for thermoforming is used. From the viewpoint of shortening, an aliphatic compound having one or more hydroxyl groups and having one mercapto group or an aliphatic compound having no mercapto group and having one or more hydroxyl groups and ester groups is preferable. From the viewpoint of shortening the half-crystallization time of the sheet for thermoforming and the excellent thermoformability even after storage at a high temperature, the aliphatic guanamine containing a hydroxyl group in the organic crystal nucleating agent does not contain a hydroxyl group. The total content of the aliphatic guanamine is preferably 40% by mass or more, more preferably 60% by mass or more, still more preferably 80% by mass or more, and still more preferably 100% by mass.

[Non-ionic surfactant]

In addition to the polylactic acid resin, the plasticizer, and the organic nucleating agent, the polylactic acid resin composition constituting the sheet for thermoforming of the present invention preferably contains the following formula from the viewpoint of transparency ( 1) A nonionic surfactant represented.

R ¹ -O(A ¹ O) _p -R ² (1)

[wherein, R ¹ represents an alkyl group having 8 to 22 carbon atoms, a mercapto group having a total carbon number of 8 to 22, or a hydrogen atom, and R ² represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a total carbon number 2 a thiol group of ~4, A ¹ represents an alkylene group having a carbon number of 2 or 3, and p represents an average addition molar number of the oxygen-extended alkyl group, which is represented by (A ¹ O) for satisfying the number of 0 < p ≦ 300 The p oxygen alkyl groups may be the same or different, and the repeating unit may be either a block type or a random type in different cases]

R ¹ in the formula (1) represents an alkyl group having 8 to 22 carbon atoms, a mercapto group having a total carbon number of 8 to 22, or a hydrogen atom.

The alkyl group having 8 to 22 carbon atoms may be a straight chain or a branched chain, and may be saturated or unsaturated. Specifically, an octyl group, a decyl group, a fluorenyl group, and an undecyl group may be mentioned. , dodecyl (lauryl), tridecyl, tetradecyl (myristyl), pentadecyl, hexadecane a linear alkyl group such as a cetyl group, a heptadecyl group, an octadecyl group (stearyl), a nonadecyl group, an eicosyl group, a behenyl group, a 2-ethylhexyl group or a 2-hexyl group. A branched alkyl group such as a mercapto group, an isodecyl group or an isostearyl group may, for example, be an unsaturated alkyl group such as an undecenyl group or an oleyl group. As the fluorenyl group having a total carbon number of 8 to 22, as long as the total carbon number is 8 to 22, it may be saturated or unsaturated, and may be exemplified by: octyl, fluorenyl, fluorenyl, undecyl fluorenyl, ten Dicarbenyl (lauryl), thirteenth carbon, fourteen carbon, fifteen carbon, sixteen carbon, seventeen carbon, eighteen carbon, nineteen carbon Further, a linear fluorenyl group such as a hexylcarbon group or a fluorenyl group may be exemplified by a branched fluorenyl group such as a 2-ethylhexyl group or an unsaturated fluorenyl group derived from oleic acid.

R ² in the formula (1) represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a fluorenyl group having 2 to 4 carbon atoms in total.

The alkyl group having 1 to 4 carbon atoms may be a straight chain or a branched chain, and specific examples thereof include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a second butyl group, and a third group. Butyl. The fluorenyl group having a total carbon number of 2 to 4 may be saturated or unsaturated, and specific examples thereof include an ethyl group, a propyl group, a butyl group and the like.

In the above, as R ² in the formula (1), in the case of the molding temperature range and the transparency, the case where R ¹ is an alkyl group having 8 to 22 carbon atoms or a fluorenyl group having a total carbon number of 8 to 22 is used. In the case, it is preferably a hydrogen atom or a methyl group, more preferably a hydrogen atom. Further, when R ¹ in the formula (1) is a hydrogen atom, it is preferred that R ² is also a hydrogen atom.

A ¹ in the formula (1) represents an alkylene group having 2 or 3 carbon atoms, and A ¹ O represents an oxygen-extended alkyl group. The alkylene group having a carbon number of 2 or 3 may be a straight chain or a branched chain, and examples thereof include an ethyl group, a propyl group, an isopropyl group and the like, and preferably an ethyl group or an isopropyl group. Further, p A ¹ O may be the same or different, and the repeating unit may be a block type or a random type in different cases, but from the viewpoint of a molding temperature range and transparency, it is preferably Block type, preferably polyoxypropylene-polyoxyethylene-polyoxypropylene type, polyoxyethylene-polyoxypropylene-polyoxyethylene type block type, more preferably polyoxypropylene-polyoxyethylene-polyoxygen Block type of propylene type.

The p in the formula (1) represents the average addition mole number of the oxygen-extended alkyl group, and is 0 < p ≦ 300, but in terms of the molding temperature range and transparency, R ¹ is a carbon number of 8 to 22 In the case of an alkyl group or a fluorenyl group having a total carbon number of 8 to 22, it is preferably 2 ≦ p ≦ 50, more preferably 5 ≦ p ≦ 20. In the case where R ¹ is a hydrogen atom, it is preferably 10 ≦p ≦ 200, more preferably 20 ≦ p ≦ 100. Further, in the case where both R ¹ and R ² are a hydrogen atom, it is preferably 10 ≦p ≦ 200, more preferably 20 ≦ p ≦ 100. Further, when R ¹ is a hydrogen atom, (A ¹ O) _p preferably contains a different A ¹ O, more preferably polyoxypropylene - from the viewpoint of a molding temperature range and transparency. a polyoxyethylene-polyoxypropylene type, a polyoxyethylene-polyoxypropylene-polyoxyethylene type block type, and further preferably a polyoxypropylene-polyoxyethylene-polyoxypropylene type block type, in which case The number (p') of A ¹ O constituting each block unit is preferably 5 ≦p' ≦ 80, more preferably 5 ≦ p' ≦ 60. Further, in terms of the molding temperature range and transparency, the mass ratio (EO/PO) of polyoxyethylene (EO) to polyoxypropylene (PO) in this case is preferably 5/95 to 70/30. More preferably, it is 5/95~60/40, and further preferably 10/90~50/50, and more preferably 10/90~40/60, and even more preferably 10/90~30/70, and further Good for 15/85~25/75.

The average molecular weight of the compound represented by the formula (1) is preferably 300 or more, and more preferably 500 or more, from the viewpoint of improving the fluidity at the time of melt-kneading of the raw material of the polylactic acid resin composition or the bleed resistance during molding. It is preferably 100,000 or less, more preferably 50,000 or less, further preferably 10,000 or less, and still more preferably 6,000 or less. In addition, from the viewpoint of heat resistance of the sheet in the amorphous state or the semi-crystalline state of the polylactic acid resin composition, it is preferably 1,000 or more, more preferably 2,000 or more, and is preferably 6,000 or less. In addition, in the present specification, the average molecular weight of the nonionic surfactant can be determined by a usual measurement method such as GPC (Gel Permeation Chromatography).

Specific examples of the compound represented by the formula (1) include a mono or diether compound of a polyhydric alcohol having a carbon number of 8 to 22 and a polyoxyethylene glycol or a polyoxypropylene glycol, or a carbon number of 8 to 22 a mono- or diesterified fatty acid with polyoxyethylene glycol or polyoxypropylene glycol, and a carbon number of 8 The methyl ether of the fatty acid of ~22 and the monoester of polyoxyethylene glycol or polyoxypropylene glycol is preferably a fatty acid polyoxyethylene glycol ester or a fatty acid and a methyl polyglycol from the viewpoint of transparency. The ester is more preferably an ester of a long-chain fatty acid such as oleic acid and a polyglycol.

The compound represented by the formula (1) may be a commercially available product, and may be synthesized by a known production method. Preferred examples of the commercially available product include fatty acid polyoxyethylene glycol esters (for example, EMANON series such as "EMANON 4110" manufactured by Kao Corporation). Moreover, as another preferable example, a polymer type nonionic polyoxyethylene-polyoxypropylene copolymer (for example, a non-ionic series of Adeka Pluronic manufactured by ADEKA Co., Ltd.) is mentioned, but fluidity and a molded body are mentioned. From the viewpoint of transparency or compatibility with the polylactic acid resin at the time of melting, a so-called reverse block type Adeka Pluronic non-ion which is obtained by addition polymerization of propylene oxide to both ends of polyoxyethylene glycol is more preferable. Specifically, as a preferable commercial item, Adeka Pluronic 25R-2, 25R-1, etc. by ADEKA company are mentioned, for example.

The content of the nonionic surfactant is preferably 0.2 parts by mass or more, more preferably 0.3 mass, based on 100 parts by mass of the polylactic acid resin, from the viewpoint of shortening the transparency and the half crystallization time of the sheet for thermoforming. It is more preferably 0.7 parts by mass or more, and still more preferably 0.9 parts by mass or more, and it is preferably from the viewpoint of improving the thermoformability after storage at a high temperature and the glass transition temperature at a high temperature of the sheet for thermoforming. It is 3.0 parts by mass or less, more preferably 2.0 parts by mass or less, further preferably 1.5 parts by mass or less, further preferably 1.0 part by mass or less, and still more preferably 0.8 parts by mass or less.

In the present invention, other known surfactants other than the nonionic surfactant represented by the formula (1) can be used as long as the effects of the present invention are not impaired. The type of the surfactant is not particularly limited, and from the viewpoint of avoiding decomposition of the polylactic acid resin during kneading, it is preferred to use a surfactant other than the ionic surfactant.

[hydrolysis inhibitor]

In the polylactic acid resin composition constituting the sheet for thermoforming of the present invention, in addition to the above components, a carbodiimide compound can be further used as a thermoformability. It is a hydrolysis inhibitor.

Specifically, a monocarbodiimide compound or a polycarbodiimide compound can be mentioned. These may be used alone or in combination of two or more.

Examples of the polycarbodiimide compound include poly(4,4'-diphenylmethanecarbodiimide), poly(4,4'-dicyclohexylmethanecarbodiimide), and poly( 1,3,5-triisopropylbenzene) polycarbodiimide, poly(1,3,5-triisopropylbenzene and 1,5-diisopropylbenzene) polycarbodiimide, etc. As the monocarbodiimide compound, diisopropylcarbodiimide, di-octadecylcarbodiimide, N,N'-di-2,6-diisopropylbenzene Base carbon diimine and the like.

In order to satisfy the durability, impact resistance, and thermoformability of the molded article including the polylactic acid resin composition, the above carbodiimide compounds may be used singly or in combination of two or more. Further, poly(4,4'-dicyclohexylmethane carbodiimide) can be purchased by using Carbodilite LA-1 (manufactured by Nisshinbo Chemical Co., Ltd.), poly(1,3,5-triisopropylbenzene) polycarbon. Dioximine and poly(1,3,5-triisopropylbenzene and 1,5-diisopropylbenzene) polycarbodiimide can be purchased from Stabaxol P and Stabaxol P-100 (manufactured by Rhein Chemie) Further, N,N'-di-2,6-diisopropylphenylcarbodiimide can be used by purchasing Statabax I (manufactured by Rhein Chemie Co., Ltd.).

The content of the hydrolysis inhibitor is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, more preferably 0.1 parts by mass or more, more preferably from 100 parts by mass of the polylactic acid resin, from the viewpoint of the hydrolysis resistance and the thermoformability and the transparency after the high-temperature storage. The amount is preferably 0.15 parts by mass or more, and is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and still more preferably 1 part by mass or less from the viewpoint of transparency.

The polylactic acid resin composition constituting the sheet for thermoforming of the present invention may contain a lubricant, an inorganic crystal nucleating agent, a filler (inorganic filler, an organic filler), and a flame retardant within a range that does not impair the effects of the present invention. The agent, the antioxidant, the ultraviolet absorber, the antistatic agent, the antifogging agent, the light stabilizer, the pigment, the antifungal agent, the antibacterial agent, the foaming agent and the like are other components than the above components. Also, similarly, it is possible to prevent the effects of the present invention from being impaired. It contains other polymer materials or other resin compositions.

The sheet for thermoforming of the present invention may be a polylactic acid resin composition containing a polylactic acid resin, a specific amount of a plasticizer, and a specific amount of an organic crystal nucleating agent, and the polylactic acid resin composition may contain The above components can be produced without particular limitation. For example, a polylactic acid resin, a specific amount of a plasticizer, and a specific amount of organic crystal nucleation can be used using a known kneading machine such as a closed kneader, a uniaxial or biaxial extruder, or an open roll kneader. The preparation and the raw materials of various additives as needed are melt-kneaded and prepared. The raw materials may be uniformly mixed in advance using a Henschel mixer, a high-speed mixer, or the like, and then melt-kneaded. Further, in the preparation of the polylactic acid resin composition, in order to promote the plasticity of the polylactic acid resin, the raw material may be melt-mixed in the presence of a supercritical gas, and after melt-kneading, the melt-kneaded product may be dried according to a known method. cool down.

The melt kneading temperature is not less than the melting point (Tm) of the polylactic acid resin, and preferably in the range of Tm ° C or more and Tm + 100 ° C or less, from the viewpoint of improving the moldability and deterioration prevention property of the polylactic acid resin composition. It is a range of Tm ° C or more and Tm + 50 ° C or less. Specifically, for example, it is preferably 170 ° C or higher, and preferably 240 ° C or lower, more preferably 220 ° C or lower. The melt kneading time varies depending on the melt kneading temperature and the type of the kneading machine, and cannot be determined in any way, but is preferably 15 seconds or longer and 900 seconds or shorter. Further, in the present specification, the melting point (Tm) and the glass transition temperature (Tg) can be determined by the methods described in the following examples.

Since the melt kneaded material obtained in this manner is excellent in transparency and thermoformability, it is molded into a primary processed product containing a polylactic acid resin composition, that is, a sheet for thermoforming of the present invention.

The sheet for thermoforming of the present invention is not particularly limited as long as the polylactic acid resin composition is used, and can be produced by extrusion molding, injection molding, or press molding.

Specifically, the extrusion molding can be carried out by extruding the polylactic acid resin composition filled in the heated extruder and extruding it from a T-die to obtain a sheet-like molded article (also referred to as a sheet-like product). As a sheet molded product). The sheet molded article is brought into contact with a cooling roll to be cooled, separated from the cooling roll, and then wound up by a take-up roll, whereby the sheet for thermoforming of the present invention can be obtained. Further, when filling the extruder, the raw material constituting the polylactic acid resin composition, for example, a material containing a polylactic acid resin, a plasticizer, an organic crystal nucleating agent, and optionally various additives may be directly filled. In the case of melt kneading, the melt kneader may be filled in the extruder.

The temperature of the extruder is preferably 170 ° C or higher, and preferably 240 ° C or lower, more preferably 220 ° C or lower, from the viewpoint of uniformly mixing the polylactic acid resin composition and preventing deterioration of the polylactic acid resin. Further, in the present invention, the temperature of the extruder means the barrel set temperature of the extruder. Further, the residence time in the extruder depends on the thickness or width of the sheet and the take-up speed, so that it cannot be specified, but from the viewpoint of avoiding deterioration due to heat, it is preferably from about 30 seconds to several minutes. .

From the viewpoint of obtaining a sheet in an amorphous state or a semi-crystalline state, the temperature of the cooling roll is preferably set to be less than the Tg of the polylactic acid resin composition, and specifically, preferably less than 40 ° C, more preferably It is 30 ° C or lower, and more preferably 20 ° C or lower. In the present specification, the amorphous state and the semi-crystalline state are in an amorphous state when the relative crystallinity determined by the following formula is less than 60%, and the relative crystallinity is 60% or more. The case of less than 80% is set to a semi-crystalline state. Therefore, the sheet in an amorphous state or a semi-crystalline state means a sheet having a relative crystallinity of less than 80%.

Relative crystallinity (%) = {(ΔHm - ΔHcc) / ΔHm} × 100

Specifically, regarding the relative crystallinity, a DSC (Differential Scanning Calorimetry) device (Diamond DSC manufactured by PerkinElmer Co., Ltd.) can be used as the first operation (1stRUN) at a temperature increase rate of 20 ° C / min from 20 . °C was heated to 200 ° C, kept at 200 ° C for 5 minutes, then cooled from 200 ° C to 20 ° C at a cooling rate of -20 ° C / min, held at 20 ° C for 1 minute, and further, as a second operation (2ndRUN ), the temperature is raised from 20 ° C to 200 ° C at a heating rate of 20 ° C / min, using the first operation The absolute value ΔHcc of the cold crystallization enthalpy of the polylactic acid resin observed in the above, and the crystal melting 焓 ΔHm observed in the second operation were determined.

The time of contact with the cooling roll differs depending on the set temperature of the cooling roll, the number of cooling rolls, the extrusion speed, and the sheet winding speed. Therefore, it is not necessarily a rule, but for example, amorphous is obtained efficiently. From the viewpoint of the sheet in a state or a semi-crystalline state, it is preferably 0.1 second or longer, more preferably 0.5 second or longer, further preferably 0.8 second or longer, and more preferably 50 seconds or shorter, more preferably 10 seconds or shorter. More preferably, it is 5 seconds or less. Further, the sheet winding speed is preferably 0.1 m/min or more, more preferably 0.5 m/min or more, still more preferably 1 m/min or more, and preferably 50 m/min. Hereinafter, it is more preferably 30 m/min or less, further preferably 20 m/min or less.

In the case where the sheet for thermoforming of the present invention is formed by injection molding, specifically, the temperature of the cylinder can be preferably set to 180 ° C or higher from the viewpoint of uniform mixing and suppression of molecular weight. An injection molding machine of 220 ° C or less, more preferably 210 ° C or less is preferable, and the polylactic acid resin composition is filled in a mold having a desired shape to be formed into a sheet shape.

In the case where the sheet for thermoforming of the present invention is formed by press molding, specifically, the above-mentioned polylactic acid resin composition can be surrounded by a frame having a desired sheet shape to perform press forming, and the present invention can be obtained. Sheet for thermoforming.

The temperature and pressure for press molding are preferably from 170 to 240 ° C and from 5 to 30 MPa, more preferably from 175 to 220 ° C and from 10 to 25 MPa, from the viewpoint of uniform mixing and suppression of molecular weight. Further, it is preferably pressed at 180 to 210 ° C and 10 to 20 MPa. The pressing time varies depending on the temperature and pressure of pressing, and cannot be determined in any way. However, from the viewpoint of uniform mixing, it is preferably 1 minute or longer, preferably 10 minutes or shorter, more preferably 7 minutes or shorter, and further preferably Less than 5 minutes.

Moreover, it is preferred to carry out the pressing under the above conditions immediately after the conditions of preferably 0 to 40 ° C and 0.1 to 20 MPa, more preferably 10 to 30 ° C and 0.1 to 10 MPa. Preferably, it is pressed and cooled under conditions of 10 to 20 ° C and 0.1 to 5 MPa. The polylactic acid resin composition of the present invention can be cooled to a temperature less than its Tg by pressing under the temperature conditions, thereby maintaining an amorphous state or a semi-crystalline state. The pressing time varies depending on the temperature and pressure of the pressing, and cannot be determined in any way. However, from the viewpoint of cooling efficiency and productivity, it is preferably 1 minute or longer, and preferably 10 minutes or shorter, more preferably 7 minutes or shorter. It is preferably 5 minutes or less.

The sheet for thermoforming of the present invention was obtained in this manner. The sheet for thermoforming of the present invention is not particularly limited, and is preferably a sheet which is formed into an amorphous state or a semi-crystalline state by cooling at the time of the above molding. The sheet for thermoforming of the present invention obtained by cooling is preferably less than 80%, more preferably less than 60%, still more preferably less than 50%, calculated according to the above formula. The lower limit is not particularly set as long as it is 0% or more.

The thickness of the sheet for thermoforming of the present invention is preferably 0.1 mm or more, more preferably 0.2 mm or more, and is preferably 1.5 mm or less, more preferably 1.4 mm or less, still more preferably 1.2 mm or less.

Moreover, the glass transition temperature of the sheet for thermoforming of the present invention is preferably 50 ° C or higher, more preferably 51 ° C or higher, and still more preferably 52 ° C or higher, and more preferably from the viewpoint of storage stability and moldability. It is preferably 60 ° C or lower, more preferably 59 ° C or lower, and still more preferably 58 ° C or lower.

The half-crystallization time of the sheet for thermoforming of the present invention is preferably 5 seconds or longer, more preferably 8 seconds or longer, further preferably 10 seconds or longer, and preferably 27 seconds or less, from the viewpoint of moldability. More preferably, it is 25 seconds or less, More preferably, it is 24 second or less. Further, in the present specification, the half crystallization time can be determined by the method described in the following examples.

Moreover, the present invention provides a method for producing a sheet for thermoforming of the present invention. Specifically, the step of preparing the sheet for thermoforming of the present invention is not particularly limited, and examples thereof include a method of winding by a take-up roll, and may be exemplified by cooling by a cooling roll. Cutting to a specific length and manufacturing it in a stacked state The method includes a method of continuously forming a sheet for thermoforming into a continuous molding method without directly forming a sheet into a thermoforming machine. In general, a production method in which a sheet is formed into a roll by a "winding step" is generally performed from the viewpoint of storage of the product or the storage of the sheet and subsequent conveyance. Further, as a method of cooling, in addition to the method of contacting the cooling rolls, the contact with the metal plate for cooling, the blowing of air after cooling (air knife), the water tank for cooling, and the like can be used. Further, for example, contact with a metal roller for temperature adjustment, contact with a metal plate for temperature adjustment, air blowing (air knife) after temperature adjustment, a temperature adjustment groove by infrared rays or a hot wire heater, or the like may be used.

Specifically, for example, it includes an "extrusion and cooling step", which is carried out from melt kneading in an extruder to extrusion using a T-die, and then extruded from a T-die by a cooling roll. The sheet is cooled; and the "winding step" is followed by taking up a roll at a certain tension or a certain take-up speed. Depending on the environment of the manufacturing site or the period of manufacture, there is a case where the surface temperature of the sheet rises during the winding step, and if the sheet is rolled into a roll shape in a state where the surface temperature of the sheet is high, the sheet may be slight, but it may cause a sheet. The material is produced to extend in the direction of extrusion. The sheet thus obtained is slightly extended and the phase difference of the sheet becomes large, so that it adversely affects the subsequent thermoformability (temperature range at which molding can be formed). Therefore, in order to suppress excessive temperature rise in the winding step, it is preferable to adjust (cool) the sheet surface temperature to be low, and the sheet surface temperature is 0 to 50 ° C in the winding step, which is good in manufacturing. Sheet for thermoforming. The surface temperature of the sheet can be measured using a contact or non-contact thermometer. Further, the conditions of the melt kneading, the conditions for cooling, and the conditions for winding are as described above.

Hereinafter, preferred embodiments of the method for producing a sheet for thermoforming of the present invention are listed. That is, a method of producing a sheet for thermoforming including the following steps (A) and (B) is listed. Further, the set temperature of the extruder or the set temperature of the cooling roll is as described above.

Step (A): In the extruder having a temperature of 170 to 240 ° C, 0.5 to 3.5 parts by mass of the plasticizer and 0.15 to the organic crystal nucleating agent are contained in the polylactic acid resin relative to 100 parts by mass of the polylactic acid resin. 0.45 parts by mass of the polylactic acid resin composition is extruded to prepare a sheet to form Step (B): The sheet molded article obtained by the step (A) is cooled by contact with a cooling roll having a temperature of less than 40 °C.

In the step (A), a sheet-formed article is prepared by extruding the polylactic acid resin composition of the present invention by an extruder. The constituent components or contents of the above polylactic acid resin composition are the same as described above. Further, the set temperature of the extruder is preferably 170 ° C or higher, and preferably 240 ° C or lower, more preferably 220 ° C or lower. Other extrusion conditions are as described above.

In the step (B), the sheet molded article obtained by the step (A) is brought into contact with a cooling roll to be cooled. Thereby, the obtained sheet for thermoforming can be favorably maintained in an amorphous state or a semi-crystalline state. The set temperature of the cooling roll is preferably less than 40 ° C, more preferably 30 ° C or less, still more preferably 20 ° C or less. Other cooling conditions are as described above.

The sheet for thermoforming of the present invention thus obtained can be used for various purposes because of its excellent thermoformability. For example, it can be thermoformed into a blister bag or a tray for a packaging material such as daily necessities, cosmetics, home electric appliances, and the like. Food containers, industrial pallets for the transportation or protection of industrial parts, etc. Therefore, the present invention further provides a thermoformed body obtained by molding the sheet for thermoforming of the present invention.

The thermoformed body of the present invention may be formed by thermoforming the sheet for thermoforming of the present invention, and the molding method is not particularly limited, and it can be carried out by a known method such as vacuum forming or pressure forming.

As a preferable aspect of the method for producing a hot formed body of the present invention, a method for producing a hot formed body comprising the following steps (1) and (2) can be mentioned.

Step (1): The heat of the polylactic acid resin composition containing 0.5 to 3.5 parts by mass of the plasticizer and 0.15 to 0.45 parts by mass of the organic crystal nucleating agent in 100 parts by mass of the polylactic acid resin in the polylactic acid resin The sheet for forming is heated to a temperature above the glass transition temperature (Tg) of the above polylactic acid resin composition and not reaching the melting point (Tm)

Step (2): using a mold having a mold temperature of 60 to 140 ° C to obtain the obtained by the step (1) Sheet thermoforming

The sheet for thermoforming used in the step (1) is the sheet for thermoforming of the present invention, and its constituent components or contents are the same as described above. Further, since the sheet for thermoforming must be softened in an amorphous state by the heating in the step (1), it is necessary to set the surface temperature of the sheet to be higher than the glass transition temperature (Tg) of the polylactic acid resin composition. The melting point (Tm). The heating temperature of the sheet for thermoforming is preferably 50 ° C or higher, more preferably 60 ° C or higher, further preferably 65 ° C or higher, and preferably 120 ° C or lower, more preferably 100 ° C or lower, further preferably 90. Below °C.

In the step (2), thermoforming is carried out using a mold of a desired shape. Specifically, for example, the sheet for thermoforming which is heated in the step (1) is directly placed in a mold in a vacuum pressure forming machine, and the inside of the mold is heated to a specific temperature and kept pressurized. The formed body after vacuum forming or pressure forming is obtained in an unpressurized state. The mold temperature is 60° C. or higher, preferably 70° C. or higher, more preferably 75° C. or higher, and still more preferably 80° C. or higher, from the viewpoint of improving the crystallization rate of the polylactic acid resin composition and improving workability. From the same viewpoint, it is 140 ° C or lower, preferably 120 ° C or lower, more preferably 115 ° C or lower, and still more preferably 110 ° C or lower. The holding time in the mold is preferably from 2 to 60 seconds, more preferably from 3 to 60 seconds, in terms of the heat resistance and productivity of the hot formed body comprising the polylactic acid resin composition. ~30 seconds, and more preferably 5 to 20 seconds, in the mold of 100 ° C, preferably 2 to 60 seconds, more preferably 3 to 30 seconds, more preferably 5 to 20 seconds, and further preferably 5 to 15 seconds. Since the polylactic acid resin composition of the present invention has a high crystallization rate, a molded article having sufficient heat resistance can be obtained even in the case of a short holding time as described above. Furthermore, the mold temperature described herein preferably refers to the set temperature of the upper mold, and the set temperature of the lower mold may be the same as or different from the upper mold, but the temperature of the lower mold is preferably lower, for example, 10~ 30 ° C.

In the thermoformed body of the present invention, the thermoformable sheet of the present invention has excellent thermoformability, and therefore has excellent formability, high crystallinity, and excellent heat resistance and transparency.

The thickness of the thermoformed body of the present invention is not particularly limited, and is preferably 0.1 mm or more, more preferably 0.15 mm or more, and still more preferably 0.2 mm from the viewpoint of obtaining a uniform molded article (secondarily processed product). The above is preferably 1.5 mm or less, more preferably 1.4 mm or less, still more preferably 1.2 mm or less.

From the viewpoint of heat resistance, the haze of the thermoformed article of the present invention is preferably 0.1% or more, more preferably 0.2% or more, still more preferably 0.3% or more, from the viewpoint of transparency. It is preferably 8.0% or less, more preferably 7.0% or less, still more preferably 6.5% or less. Further, in the present specification, the haze value is an index of transparency, and can be measured by the method described in the following examples.

Further, the relative degree of crystallinity of the thermoformed body of the present invention is preferably 80% or more, more preferably 90% or more. Furthermore, the upper limit is not specifically set.

The secondary processing method of the sheet for thermoforming of the present invention is not particularly limited as long as it is a method of molding the sheet by vacuum molding or pressure forming.

In this way, the obtained hot-formed body of the present invention has high crystallinity, is excellent in heat resistance, and is excellent in transparency, exudation resistance and strength, and can be used in various applications. Among them, it can be preferably used for various purposes. It is a blister bag or tray for packaging materials such as daily necessities, cosmetics, home appliances, etc., food containers such as lids for lunch, and industrial trays for transportation or protection of industrial parts.

In the above embodiment, the present invention further discloses the following sheet for thermoforming, a method for producing the same, a molded article obtained by molding the sheet, a method for producing the same, and a method for processing the sheet.

<1> A sheet for thermoforming comprising polylactic acid containing 0.5 to 3.5 parts by mass of a plasticizer and 100 to 0.45 parts by mass of an organic crystal nucleating agent per 100 parts by mass of the polylactic acid resin. Resin composition.

<2> The sheet for thermoforming according to the above <1>, wherein the content of the polylactic acid resin is The polylactic acid resin composition is preferably 50% by mass or more, more preferably 70% by mass or more, and still more preferably 90% by mass or more.

<3> The sheet for thermoforming according to the above <1> or <2>, wherein the plasticizer is preferably a compound having two or more ester groups in the molecule, more preferably two or more molecules in the molecule. The ester group and the average addition molar number of ethylene oxide per molecule is preferably from 2 to 9, more preferably from 3 to 9.

The sheet for thermoforming according to any one of the above-mentioned items, wherein, as a plasticizer, a polyvalent carboxylic acid and a monool or a (poly)oxyalkylene adduct thereof are preferred. An ester, and an ester of a monocarboxylic or polycarboxylic acid with a polyol or a (poly)oxyalkylene adduct thereof.

The sheet for thermoforming according to any one of the above-mentioned items, wherein, as the plasticizer, it is preferred to suitably use an ethylene oxide selected from the group consisting of acetic acid and glycerin to an average of 3 to 6 moles. An ester of an ear adduct (1 to 2 moles of ethylene oxide per hydroxyl group), an average addition of acetic acid and ethylene oxide, an ester of polyethylene glycol having a molar number of 4 to 6, succinic acid and The average addition of ethylene oxide is 2~3 of polyethylene glycol monomethyl ether (each hydroxyl addition 2~3 mole ethylene oxide) ester, adipic acid and diethylene glycol single Methyl ether ester, adipic acid and 1-butanol ester, ethyl citrate and 1-butanol ester, 1,3,6-hexane tricarboxylic acid and diethylene glycol monomethyl ether ester One or more of the constituent groups, and more preferably, a polyethylene glycol monomethyl ether, adipic acid, and diethyl ether selected from the group consisting of succinic acid and ethylene oxide having an average addition molar amount of 2 to 3 are used. One or more selected from the group consisting of esters of diol monomethyl ether, esters of acetamidine citrate and 1-butanol.

The sheet for thermoforming according to any one of the above-mentioned items, wherein the content of the plasticizer is preferably 1 part by mass or more, more preferably 1.2 or more, based on 100 parts by mass of the polylactic acid resin. It is more than 3 parts by mass, more preferably not more than 2.5 parts by mass, more preferably not more than 2.5 parts by mass.

The sheet for thermoforming according to any one of the above-mentioned items, wherein the organic nucleating agent preferably has a total of two or more selected from the group consisting of an ester group and a hydroxyl group. And an aliphatic compound having one or more of the group consisting of a guanamine group, more preferably an aliphatic group having one or more hydroxyl groups and having one or more ester groups or a guanamine group Further, the compound is preferably an aliphatic compound having two or more hydroxyl groups and having one or more ester groups or a guanamine group, and more preferably having two or more hydroxyl groups and having two or more ester groups or oximes. Amino-based aliphatic compound.

The sheet for thermoforming according to any one of the above-mentioned items, wherein the organic nucleating agent is preferably a hydroxy fatty acid monodecylamine or a hydroxy fatty acid bis-decylamine, more preferably 12 - hydroxystearic acid monoethanolamine, methylenebis 12-hydroxystearylamine, ethylidenebis 12-hydroxystearylamine, hexamethylenebis 12-hydroxystearylamine.

The sheet for thermoforming according to any one of the above-mentioned items, wherein the content of the organic nucleating agent is preferably 0.2 parts by mass or more, more preferably 100 parts by mass or more based on the polylactic acid resin. It is 0.3 parts by mass or more, more preferably 0.33 parts by mass or more, and is preferably 0.4 parts by mass or less, more preferably 0.38 parts by mass or less.

The sheet for thermoforming according to any one of the above-mentioned items, wherein the polylactic acid resin composition constituting the sheet for thermoforming preferably further comprises the following formula (1). Nonionic surfactant.

R ¹ -O(A ¹ O) _p -R ² (1)

[wherein, R ¹ represents an alkyl group having 8 to 22 carbon atoms, a mercapto group having a total carbon number of 8 to 22, or a hydrogen atom, and R ² represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a total carbon number 2 a thiol group of ~4, A ¹ represents an alkylene group having a carbon number of 2 or 3, and p represents an average addition molar number of the oxygen-extended alkyl group, which is represented by (A ¹ O) for satisfying the number of 0 < p ≦ 300 The p oxygen alkyl groups may be the same or different, and the repeating unit may be either a block type or a random type in different cases]

<11> The sheet for thermoforming according to the above <10>, wherein, when R ¹ in the formula (1) is a hydrogen atom, R ² is preferably a hydrogen atom.

<12> The sheet for thermoforming according to <10> or <11> above, wherein the p A ¹ O in the formula (1) is preferably a block type, preferably a polyoxypropylene-polyoxyethylene-poly group. An oxypropylene type, a polyoxyethylene-polyoxypropylene-polyoxyethylene type block type, more preferably a polyoxypropylene-polyoxyethylene-polyoxypropylene type block type, in which case each block is formed The number of the A ¹ O (p') of the unit is preferably 5≦p'≦80, more preferably 5≦p'≦60, and the mass ratio of polyoxyethylene (EO) to polyoxypropylene (PO) ( EO/PO) is preferably 5/95 to 70/30, more preferably 5/95 to 60/40, further preferably 10/90 to 50/50, and further preferably 10/90 to 40/60. Further preferably, it is 10/90 to 30/70, and more preferably 15/85 to 25/75.

The sheet for thermoforming according to any one of the above-mentioned items, wherein the compound represented by the formula (1) has an average molecular weight of preferably 300 or more, more preferably 500 or more, and more preferably It is 100,000 or less, more preferably 50,000 or less, further preferably 10,000 or less, further preferably 6,000 or less, and more preferably 1,000 or more, more preferably 2,000 or more, and is preferably 6,000 or less.

The sheet for thermoforming according to any one of the above-mentioned <10>, wherein the content of the nonionic surfactant is preferably 0.2 parts by mass or more based on 100 parts by mass of the polylactic acid resin. It is preferably 0.3 parts by mass or more, more preferably 0.7 parts by mass or more, further preferably 0.9 parts by mass or more, and more preferably 3.0 parts by mass or less, more preferably 2.0 parts by mass or less, still more preferably 1.5 parts by mass or less. Further, it is preferably 1.0 part by mass or less, and more preferably 0.8 part by mass or less.

The sheet for thermoforming according to any one of the above-mentioned <1> to <14> wherein the carbodiimide compound is further used as a hydrolysis inhibition in the polylactic acid resin composition constituting the sheet for thermoforming. Agent.

<16> The sheet for thermoforming according to the above <15>, wherein the content of the hydrolysis inhibitor is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, more preferably 0.1 part by mass or more, more preferably 100 parts by mass of the polylactic acid resin. 0.15 parts by mass or more, and preferably 5 parts by mass or less, more preferably 3 parts by mass or less, still more preferably 1 part by mass or less.

The sheet for thermoforming according to any one of the above aspects, comprising a polylactic acid resin composition using a closed kneader, uniaxial or biaxial A well-known kneading machine such as an extruder or an open roll type kneading machine contains 0.5 to 3.5 parts by mass of a plasticizer with respect to 100 parts by mass of the polylactic acid resin, and an organic knot. The crystal nucleating agent is obtained by melt-kneading a raw material of 0.15 to 0.45 parts by mass.

<18> The sheet for thermoforming according to the above <17>, wherein the melt kneading temperature is not less than the melting point (Tm) of the polylactic acid resin, preferably in a range of Tm ° C or more and Tm + 100 ° C or less, more preferably Tm ° C. The above range of Tm + 50 ° C or less is specifically 170 ° C or more, and preferably 240 ° C or less, more preferably 220 ° C or less.

The sheet for thermoforming according to any one of the above items <1> to <18>, which can be produced by extrusion molding, injection molding, or press molding of the above polylactic acid resin composition.

The sheet for thermoforming according to any one of <1> to <19> which is a sheet in an amorphous state or a semi-crystalline state.

The sheet for thermoforming according to any one of the above-mentioned items, wherein the thickness of the sheet for thermoforming is preferably 0.1 mm or more, more preferably 0.2 mm or more, and preferably 1.5. Below mm, it is more preferably 1.4 mm or less, further preferably 1.2 mm or less.

The sheet for thermoforming according to any one of the above-mentioned items, wherein the sheet for thermoforming has a glass transition temperature of preferably 50 ° C or more, more preferably 51 ° C or more, and further preferably. It is 52 ° C or more, and preferably 60 ° C or less, more preferably 59 ° C or less, further preferably 58 ° C or less.

The sheet for thermoforming according to any one of the above aspects, wherein the half-crystallization time of the sheet for thermoforming is preferably 5 seconds or longer, more preferably 8 seconds or longer, and further preferably. It is 10 seconds or longer, preferably 27 seconds or shorter, more preferably 25 seconds or shorter, and still more preferably 24 seconds or shorter.

<24> A method for producing a sheet for thermoforming, comprising the following steps (A) and (B).

Step (A): In the extruder having a temperature of 170 to 240 ° C, 0.5 to 3.5 parts by mass of the plasticizer and 0.15 to the organic crystal nucleating agent are contained in the polylactic acid resin relative to 100 parts by mass of the polylactic acid resin. 0.45 parts by mass of the polylactic acid resin composition is extruded to prepare a sheet molded article

Step (B): cooling the sheet molded article obtained by the step (A) in contact with a cooling roll having a temperature of less than 40 ° C

<25> The method for producing a sheet for thermoforming according to the above <24>, wherein the setting temperature of the extruder in the step (A) is preferably 170 ° C or higher, and preferably 240 ° C or lower, more preferably 220 Below °C.

<26> The method for producing a sheet for thermoforming according to the above <24>, wherein the setting temperature of the cooling roll in the step (B) is preferably less than 40 ° C, more preferably 30 ° C or less, and further It is preferably 20 ° C or less.

<27> The sheet for thermoforming according to any one of the above-mentioned items <1> to <23> which can be thermoformed into a blister bag or a tray as a packaging material for daily necessities, cosmetics, home electric appliances, etc. Food containers, industrial pallets for the transportation or protection of industrial parts, etc.

<28> A thermoformed article obtained by vacuum forming or pressure forming a sheet for thermoforming according to any one of <1> to <23>.

<29> A method of producing a hot formed body comprising the following steps (1) and (2).

Step (1): The heat of the polylactic acid resin composition containing 0.5 to 3.5 parts by mass of the plasticizer and 0.15 to 0.45 parts by mass of the organic crystal nucleating agent in 100 parts by mass of the polylactic acid resin in the polylactic acid resin The sheet for forming is heated to a temperature above the glass transition temperature (Tg) of the above polylactic acid resin composition and not reaching the melting point (Tm)

Step (2): using a mold having a mold temperature of 60 to 140 ° C to thermoform the sheet obtained by the step (1)

<30> The method for producing a hot formed article according to the above <29>, wherein the heating temperature of the sheet for thermoforming in the step (1) is preferably 50 ° C or more, more preferably 60 ° C or more, and still more preferably 65 Above °C, preferably 120 ° C or less, more preferably 100 ° C or less, further preferably 90 ° C or less.

<31> A method for producing a hot formed body according to the above <29> or <30>, wherein The temperature of the mold in the step (2) is preferably 70 ° C or higher, more preferably 75 ° C or higher, further preferably 80 ° C or higher, and preferably 120 ° C or lower, more preferably 115 ° C or lower, and further preferably. It is below 110 °C.

<32> The thermoformed body according to the above <28>, wherein the thickness of the thermoformed body is preferably 0.1 mm or more, more preferably 0.15 mm or more, further preferably 0.2 mm or more, and more preferably 1.5 mm or less. Preferably, it is 1.4 mm or less, and further preferably 1.2 mm or less.

<33> The thermoformed body of the above <28> or <32>, wherein the haze value of the thermoformed body is preferably 0.1% or more, more preferably 0.2% or more, further preferably 0.3% or more, and more preferably It is 8.0% or less, more preferably 7.0% or less, further preferably 6.5% or less.

The thermoformed body according to any one of <28>, wherein the relative degree of crystallinity of the thermoformed body is preferably 80% or more, more preferably 90% or more.

<35> A method of secondary processing of a sheet for thermoforming, which is characterized in that the sheet for thermoforming according to any one of the above <1> to <23> is subjected to vacuum forming or pressure forming.

<36> The thermoformed body according to any one of <28>, <32>, <33>, <34>, which is preferably used as a blister of packaging materials for daily necessities, cosmetics, home electric appliances, and the like. Food containers such as bags or trays, lids for lunch, industrial trays for the transport or protection of industrial parts.

[Examples]

Hereinafter, the present invention will be specifically described by showing examples and comparative examples, but the present invention is not limited to the following examples. The parts in the examples are all parts by mass unless otherwise specified. In addition, "normal pressure" means 101.3 kPa, and "normal temperature" means 25 °C.

[The melting point of the polylactic acid resin composition, glass transition temperature]

Using a differential scanning calorimeter (DSC8500) (manufactured by PerkinElmer Co., Ltd.), the inflection point of the second operation measured under the following measurement conditions was defined as the glass transition temperature (Tg). Also, the peak of the endothermic peak observed near 160 ° C is set to the melting point. (Tm).

Measurement conditions: A sample of about 10 mg was placed in a standard aluminum pan manufactured by PerkinElmer Co., Ltd., and the prepared aluminum pan was placed in DSC8500, heated from 25 ° C to 200 ° C at 15 ° C / min, and then at 200 ° C. Hold for 1 minute (1st operation). Thereafter, the temperature was cooled from 200 ° C to 25 ° C at 500 ° C / min, and then the temperature was raised from 200 ° C at a rate of 15 ° C / min at 25 ° C (second operation).

Production Example 1 of plasticizer (diester compound of succinic acid and triethylene glycol monomethyl ether)

Into a four-necked flask (with a stirrer, a thermometer, a dropping funnel, a distillation tube, a nitrogen blowing tube), 363 g (3.42 mol) of diethylene glycol and a methanol solution containing 28% by mass of sodium methoxide as a catalyst were added. 6.6 g (sodium methoxide 0.034 mol) was distilled off under normal pressure at 120 ° C for 0.5 hour while distilling off methanol. Thereafter, 1000 g (6.84 mol) of dimethyl succinate (manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise over 3 hours, and methanol produced by the reaction was distilled off under normal pressure at 120 °C. Then, the mixture was cooled to 75 ° C, and the pressure was gradually reduced from normal pressure to 6.7 kPa over 1.5 hours to distill off methanol, and thereafter, it was returned to normal pressure, and then a methanol solution containing 28% by mass of sodium methoxide was added in an amount of 5.8 g. (Sodium methoxide 0.030 mol) As a catalyst, methanol was distilled off by slowly decreasing the pressure from normal pressure to 2.9 kPa at 100 ° C for 2 hours. Thereafter, the mixture was cooled to 80 ° C, and 18 g of Kyoword 600S (manufactured by Kyowa Chemical Industry Co., Ltd.) was added thereto, and the mixture was stirred at a pressure of 4.0 kPa and 80 ° C for 1 hour, and then filtered under reduced pressure. The temperature of the filtrate was raised from 70 ° C to 190 ° C for 1 hour under a pressure of 0.3 kPa, and the residual dimethyl succinate was distilled off to obtain a yellow liquid at normal temperature. Further, the amount of catalyst used was 0.94 moles relative to 100 moles of the dicarboxylate.

Examples 1 to 15 and Comparative Examples 1 to 6 Preparation of polylactic acid resin composition

In the polylactic acid resin composition, the raw materials of the compositions shown in Tables 1 to 3 were rotated at a melt kneading temperature of 180 to 190 ° C using a two-axis extruder "HK-25D" (manufactured by PARKER) at a number of revolutions of 90 r/min. Melt and knead for 10 minutes, cut the strands to obtain polylactic acid tree Granules of the lipid composition. The obtained pellets were dried at 70 ° C under reduced pressure for 1 day to have a water content of 500 ppm or less.

Preparation of sheet for thermoforming

Between two pieces of hard-chrome-polished 0.5 mm-thick stainless steel plate (manufactured by ASANUMA & CO. LTD, Ferrotype Plate Deluxe), a square spacer (thickness 0.25 mm, width 1 cm, inner side of 20 cm) and inner side thereof 15 g of the above-mentioned kneaded pellets were filled, and the mixture was pressed at a pressing temperature of 185 ° C and a pressing pressure of 0.4 MPa for 2 minutes using an automatic press molding machine (manufactured by Toyo Seiki Co., Ltd.), and further pressed at 180 ° C and 20 MPa for 2 minutes. Immediately thereafter, it was cooled by a press plate set at 15 ° C for 1 minute and 0.4 MPa to obtain a sheet (non-wafer material) (thickness: 0.25 mm) of a certain thickness.

Preparation of hot formed body

Then, the sheet for thermoforming was attached to a guide plate by a single-shot vacuum air-molding machine "FVS-500P WAKITEC" (manufactured by Asahi Kasei Co., Ltd.), and the sheet for thermoforming was heated to 80 ° C using a heater. Thereafter, the heated sheet for hot forming was vacuum-formed using a lower mold set at 100 ° C in the upper mold and 25 ° C in the lower mold, and held in a mold for 5 seconds to obtain a molded body (thickness: 0.23 mm). Regarding the temperature of the surface of the sheet, the surface temperature of the heated sheet was directly measured by a surface thermometer. Further, the mold (cover) used is shown in Fig. 1.

The properties of the obtained thermoforming sheet and the hot formed body were evaluated in accordance with the following Test Examples 1 to 5. In addition, the obtained thermoforming sheet was wound around a paper core (inner diameter: 76.2 mm, thickness: 10 mm, length: 300 mm), and placed in various temperatures (33 ° C, 35 ° C). The constant temperature and humidity machine (38 ° C) was placed in a constant temperature and humidity machine (LHL-113 manufactured by ESPEC Co., Ltd.) for 24 hours. After standing, the obtained product was prepared in accordance with the above-described molding method, and evaluated in the same manner. The results are shown in Tables 1 to 3. Furthermore, the results of samples that cannot be evaluated are indicated as "not possible".

Test Example 1 <glass transition temperature>

Using a differential scanning calorimeter (DSC8500) (manufactured by PerkinElmer Co., Ltd.), the inflection point of the second operation measured under the following measurement conditions was defined as the glass transition temperature (Tg). It is shown that the higher the glass transition temperature, the more excellent the heat resistance.

Measurement conditions: About 10 mg of the thermoforming sheet was placed in a standard aluminum pan manufactured by PerkinElmer Co., Ltd., and placed in DSC8500, heated from 25 ° C to 200 ° C at 15 ° C / min, and kept at 200 ° C for 1 minute. (The first operation). Thereafter, the temperature was cooled from 200 ° C to 25 ° C at 500 ° C / min, and then the temperature was raised from 25 ° C to 200 ° C at a rate of 15 ° C / min (second operation).

Test Example 2 <semi-crystallization time>

Using a differential scanning calorimeter (DSC8500) (manufactured by PerkinElmer Co., Ltd.), heat was measured under the following measurement conditions, and the time required for 50% crystallization was calculated based on the measured heat, and the time was set as a half crystallization time (second). ). The shorter the half crystallization time is, the more excellent the crystallization rate is.

Measurement conditions: About 10 mg of the thermoforming sheet was placed in a standard aluminum pan manufactured by PerkinElmer Co., Ltd., and placed in DSC8500, heated from 25 ° C to 90 ° C at 500 ° C / min, and then kept at 90 ° C for 10 ° C. minute.

Test Example 3 <The hot formability>

The shape and fit of the molded body were evaluated in accordance with the following methods. In addition, the molded body sample is a cover of a commercially available container (trade name: Teacup 90 Zhiye, manufactured by CP Chemicals Co., Ltd.). According to the evaluation criteria, if it is 3 or more, it is acceptable, and it is preferably 4 or more.

Shape: The shape of the obtained molded body was visually compared with the shape of the molded body sample formed by the mold (cover) of Fig. 1 by a well-trained evaluator, and evaluated according to the following evaluation criteria.

The chimerism: The obtained molded body is fitted into a body portion of a commercially available container (trade name: Teacup 90 Zhiye, manufactured by CP Chemical Co., Ltd.) 81 mm, height 51 mm, made of PP (polystyrene) made of PP (polypropylene), evaluated by the following evaluation criteria by well-trained evaluators.

[evaluation standard]

4: It has the same shape as the molded body sample, and can be fitted without applying a load.

3: It is the same shape as the molded body sample, and can be fitted by applying a load.

2: It is basically the same shape as the molded body sample, and it can be barely fitted.

1: Obviously different from the shape of the molded body sample, or not fitted.

Test Example 4 <Crystallinity>

For the thermoforming sheet and the thermoformable body which can be fitted in the evaluation of the above-mentioned fitting property, 7.5 mg was accurately weighed and sealed in an aluminum pan, and then a differential scanning calorimeter (DSC8500) (manufactured by PerkinElmer Co., Ltd.) was used. As the first operation, the temperature was raised from 25 ° C to 200 ° C at a heating rate of 15 ° C / min, held at 200 ° C for 1 minute, and then cooled from 200 ° C to 25 ° C at a cooling rate of -500 ° C / min. After the temperature was maintained at ° C for 1 minute, the temperature was raised from 25 ° C to 200 ° C at a temperature increase rate of 15 ° C/min in the second operation, and the absolute crystal crystallization of the polylactic acid resin observed in the first operation was determined. The value ΔHc, the crystal melting 焓 ΔHm observed in the second operation, and the relative crystallinity (%) were determined from the obtained values according to the following formula, and the crystallinity was evaluated. When the relative crystallinity is less than 80%, it is in an amorphous state, and when it is 80% or more, it is in a crystalline state.

Relative crystallinity (%) = {(ΔHm - ΔHc) / ΔHm} × 100

Test Example 5 <Transparency>

The haze value (%) was measured by using a haze meter (HAZE METER) "HM-150 type" (manufactured by Murakami Color Research Laboratory Co., Ltd.), and the haze value (%) was measured. It serves as an indicator of transparency. The smaller the value of the haze value is, the more excellent the transparency is.

Further, the raw materials in Tables 1 to 3 are as follows.

[Polylactic acid resin]

NW4032D: Poly L-lactic acid (optical purity 98.5%), manufactured by Nature Works

[Plasticizer]

(MeEO ₃ ) ₂ SA: a diester compound produced in Production Example 1 of the above plasticizer

DAIFATTY-101: Diester of adipic acid and diethylene glycol monomethyl ether / benzyl alcohol = 1 / 1 mixture, manufactured by Da Ba Chemical Industry Co., Ltd.

ATBC: Ethylene tributyl citrate, manufactured by Tiangang Chemical Company

[Organic Crystal Nucleating Agent]

Slipacks H: Ethyl di- 12-hydroxystearylamine, manufactured by Nippon Kasei Co., Ltd.

Slipacks O: Ethyl dioleylamine, manufactured by Nippon Kasei Co., Ltd.

[Non-ionic surfactant]

Adeka Pluronic 25R-2: Polyoxyethylene-polyoxypropylene copolymer, manufactured by ADEKA, having an average molecular weight of 3,500, wherein R ¹ and R ² in the formula (1) are hydrogen atoms, and (A ¹ O) _p is polyoxypropylene - a polyoxyethylene-polyoxypropylene type block type, a polyoxypropylene p' is 47, a polyoxyethylene p' is 16, and a total p of 63 in the formula (1)

[hydrolysis inhibitor]

Carbodilite LA-1: Aliphatic polycarbodiimide compound, manufactured by Nisshinbo Chemical

As is apparent from the results of Tables 1 to 3, the sheet for thermoforming of the present invention is excellent in thermoforming even after storage at a high temperature, and the obtained thermoformed body exhibits high crystallinity and has good transparency. Sexual, good appearance.

[Industrial availability]

Since the sheet for thermoforming of the present invention has high thermoformability, it can be preferably used for various purposes such as packaging materials for food containers, daily necessities, and home electric appliances, and trays for industrial parts.

1‧‧‧Sampling surface

Claims (14)

A sheet for thermoforming comprising a polylactic acid resin composition containing 0.5 to 3.5 parts by mass of a plasticizer and 0.15 to 0.45 parts by mass of an organic crystal nucleating agent in 100 parts by mass of the polylactic acid resin in the polylactic acid resin. . The sheet for thermoforming according to claim 1, wherein the sheet for thermoforming has a glass transition temperature of 50 to 60 °C. The sheet for thermoforming according to claim 1, wherein the half-crystallization time of the sheet for thermoforming is 5 to 27 seconds, and the haze of the obtained hot-formed body is 0.1 to 8.0%. The sheet for thermoforming according to claim 1, wherein the organic crystallization nucleating agent comprises one or more selected from the group consisting of an ester group, a hydroxyl group, and a guanamine group in a total of two or more molecules in the molecule. The base of the aliphatic compound. The sheet for thermoforming of claim 1, wherein the plasticizer comprises a compound having two or more ester groups in the molecule. The sheet for thermoforming according to claim 1, wherein the polylactic acid resin composition further contains a nonionic surfactant represented by the following formula (1), R ¹ -O(A ¹ O) _p -R ² (1) Wherein R ¹ represents an alkyl group having 8 to 22 carbon atoms, a mercapto group having a total carbon number of 8 to 22, or a hydrogen atom, and R ² represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or a total carbon number a thiol group of 2 to 4, A ¹ represents an alkylene group having a carbon number of 2 or 3, and p represents an average addition molar number of the oxygen-extended alkyl group, which is a number satisfying 0 < p ≦ 300, (A ¹ O) The p-oxyalkylene groups may be the same or different, and the repeating unit may be either a block type or a random type in different cases. The sheet for thermoforming according to claim 1, wherein the sheet for thermoforming is a sheet in an amorphous state or a semi-crystalline state. A method for producing a sheet for thermoforming, comprising the following steps (A) and (B): Step (A): In the extruder having a temperature of 170 to 240 ° C, 0.5 to 3.5 parts by mass of the plasticizer and 0.15 to the organic crystal nucleating agent are contained in the polylactic acid resin relative to 100 parts by mass of the polylactic acid resin. 0.45 parts by mass of the polylactic acid resin composition is extruded to prepare a sheet-formed article; and step (B): cooling the sheet-formed article obtained by the step (A) in contact with a cooling roll having a temperature of less than 40 ° C . A method of producing a thermoformed body, comprising the following steps (1) and (2): Step (1): heating the sheet for thermoforming according to any one of claims 1 to 7 to a polylactic acid resin composition The glass transition temperature (Tg) is not higher than the melting point (Tm); Step (2): The sheet obtained by the step (1) is thermoformed using a mold having a mold temperature of 60 to 140 °C. The production method of claim 9, wherein the relative degree of crystallinity of the thermoformed body is 80% or more. A molded body obtained by vacuum forming or pressure forming a sheet for thermoforming according to any one of claims 1 to 7. A method of secondary processing of a sheet, characterized in that the sheet for thermoforming according to any one of claims 1 to 7 is subjected to vacuum forming or pressure forming. A packaging material comprising the shaped body of claim 11. A sheet for thermoforming, which has a glass transition temperature of 50 to 60 ° C, a half crystallization time of 5 to 27 seconds, and a haze value of the obtained thermoformed body of 0.1 to 8.0%.