JP2017024407A - Polylactic acid resin composition laminated sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polylactic acid resin composition laminated sheet which combines high impact resistance with transparency, and a method for manufacturing the laminated sheet.SOLUTION: There is provided the polylactic acid resin composition laminated sheet which comprises a plurality of layers of a polylactic acid resin composition and comprises at least the following layer P and layer Q, and in which the layer P is a layer of a polylactic acid resin composition containing a polylactic acid resin, a plasticizer, and an organic crystal nucleating agent, a content of the plasticizer in the layer P is 4 mass% or more and 18 mass% or less, a content of the organic crystal nucleating agent in the layer P is 0.05 mass% or more and 1.0 mass% or less, the layer Q is a layer of a polylactic acid resin composition containing a polylactic acid resin, a plasticizer, and an organic crystal nucleating agent, a content of the plasticizer in the layer Q is 0 mass% or more and 6 mass% or less, a content of the organic crystal nucleating agent is 0 mass% or more and 0.3 mass% or less, and the content of the plasticizer in the layer P is more than the content of the plasticizer in the layer Q, and at least the outermost layer on the surface side and the rear side of the sheet is the layer P.SELECTED DRAWING: None

Description

  The present invention relates to a polylactic acid resin composition laminated sheet. More specifically, the present invention relates to a polylactic acid resin composition laminated sheet that can be suitably used for molded articles such as packs and trays of daily necessities, cosmetics, home appliances, and the like, and a method for producing the sheet.

  Polylactic acid resin is expected to be used because the raw material is plant-derived and therefore emits very little carbon dioxide. However, due to the characteristics of the resin being rigid and highly transparent, it is laminated. A technology for imparting functionality through conversion is being studied.

  For example, Patent Document 1 discloses a resin composition containing 1 to 20 parts by weight of a liquid additive (B) with respect to 100 parts by weight of a resin (A) mainly composed of an aliphatic polyester resin such as a polylactic acid resin. At least one layer comprising the product (C) as a surface layer, and 100 parts by weight of a resin (D) mainly composed of an aliphatic polyester resin having a crystal melting point of 120 ° C. to 250 ° C. of the aliphatic polyester resin. On the other hand, when the stretched film comprising at least two layers containing at least one layer containing or not containing the liquid additive (B) is less than 1 part by weight, the tensile elastic modulus is high, and the heat resistance and adhesion are excellent. It is disclosed.

  In Patent Document 2, when layer A made of a polylactic acid-based resin composition containing a crystal nucleating agent is laminated so as to be sandwiched between layers B made of a resin composition containing substantially no crystal nucleating agent, heat resistance, A polylactic acid-based resin sheet with good moldability that can obtain a molded article excellent in both transparency and gloss has been obtained.

  Patent Document 3 discloses a glass transition temperature Tg (A), an A layer mainly composed of a crystalline polylactic acid polymer A having a melting point Tm (A), a glass transition temperature Tg (B), and a crystallization temperature Tc. (B) is a laminated film composed of a B layer composed mainly of the crystalline resin composition B, wherein the relationship between Tg (A), Tm (A), Tg (B) and Tc (B) is Tg (A) ≧ Tg (B) and Tm (A) ≧ Tc (B), the heat of crystal fusion (ΔHm) of the film in the DSC temperature rise measurement is 15 J / g or more, and the layer structure is A / B / A laminated film characterized by having three or more layers including the configuration of A or B / A / B is disclosed. Such a laminated film can be imparted with various properties only by changing the crystalline resin to be laminated without greatly changing the film formation conditions of crystalline polylactic acid.For example, sufficient tearability or solvent resistance is imparted. It has been reported.

  On the other hand, a resin sheet or film in which a surface layer is laminated on the front and back of the central layer to form a three-layer structure, and the central layer is made of 100% polylactic acid and has a thickness of 60% to The surface layer is composed of 70% to 95% polylactic acid and 5% to 30% lactic acid copolymer polyester as components, and the surface layer is 5% to the total thickness. It is disclosed that a resin sheet or film having a thickness of 20% can improve biodegradability and does not cause damage to packaging containers and scattered pieces associated therewith (patent) Reference 4).

  Patent Document 5 discloses a laminated sheet including a layer A and a layer B made of a polylactic acid-based resin composition, and each of the layer A and the layer B contains poly (meth) acrylate with a specific content. It is disclosed that the inclusion of a polylactic acid-based resin laminate sheet that is excellent in transparency and heat resistance and that can provide a molded product having a high plant degree can be provided.

  Patent Document 6 is a laminated sheet consisting of at least three layers having layer A as at least one outermost layer and layer B as an inner layer, wherein layer A comprises polylactic acid and polybutylene succinate resin. In addition, in 100% by mass of all components of layer A, polylactic acid is 60% by mass or more and 97.5% by mass or less, and the ratio of the thickness of layer A is 100% of the total thickness of the laminated sheet. 10 to 40%, layer B contains polylactic acid and polybutylene succinate resin, and polylactic acid is 90% by mass or more and less than 100% by mass in 100% by mass of all components of layer B, A laminated sheet having an orientation degree ΔP of 0 or more and 0.002 or less is disclosed. It is described that this laminated sheet is excellent in impact resistance, transparency and blocking resistance, and is particularly suitable for use in molded products and printing.

JP 2000-37837 A JP 2007-210190 A JP 2005-144726 A JP 2006-305992 A WO2007 / 063864 WO2010 / 103915 Publication

  However, when an attempt was made to prepare a laminated sheet excellent in the transparency of the polylactic acid resin, it was found that if the impact resistance was improved, the transparency was lowered, and further improvement was necessary.

  The present invention relates to a polylactic acid resin composition laminated sheet having both high impact resistance and transparency, and a method for producing the laminated sheet.

The present invention relates to the following [1] to [2].
[1] A polylactic acid resin composition laminated sheet including a plurality of polylactic acid resin composition layers, and a polylactic acid resin composition laminated sheet including at least the following layers P and Q,
Layer P is a layer of a polylactic acid resin composition containing (P-A) polylactic acid resin, (P-B) plasticizer, and (P-C) organic crystal nucleating agent, and (P- B) The content of the plasticizer is 4% by mass or more and 18% by mass or less, and the content of the (PC) organic crystal nucleating agent is 0.05% by mass or more and 1.0% by mass or less,
Layer Q is a layer of a polylactic acid resin composition containing (QA) polylactic acid resin, (QB) plasticizer, and (QC) organic crystal nucleating agent, and (Q- B) The content of the plasticizer is 0% by mass or more and 6% by mass or less, and the content of the (QC) organic crystal nucleating agent is 0% by mass or more and 0.3% by mass or less.
Here, the content of the (P-B) plasticizer in the layer P is greater than the content of the (Q-B) plasticizer in the layer Q, and at least one of the outermost layers on the front and back sides of the sheet Is a polylactic acid resin composition laminate sheet in which layer P is.
[2] A method for producing a polylactic acid resin composition laminate sheet comprising a plurality of polylactic acid resin composition layers, comprising the following steps (1), (2) and (3): Production method.
Step (1): Polylactic acid resin constituting layer P by melting and kneading raw materials containing (PA) polylactic acid resin, (PB) plasticizer, and (PC) organic crystal nucleating agent In the step of preparing the composition, the content of the (P-B) plasticizer in the layer is 4% by mass or more and 18% by mass or less, and the content of the (PC) organic crystal nucleating agent is 0.00. Process step (2) which is not less than 05% by mass and not more than 1.0% by mass: A raw material containing (QA) polylactic acid resin, (QB) plasticizer, and (QC) organic crystal nucleating agent A step of preparing a polylactic acid resin composition constituting the layer Q by melt-kneading, wherein the content of the (Q-B) plasticizer in the layer is 0% by mass to 6% by mass, (Q -C) The content of the organic crystal nucleating agent is 0% by mass or more and 0.3% by mass or less,
Here, the content of the (P-B) plasticizer in the layer P is larger than the content of the (Q-B) plasticizer in the layer Q. The process step (3): obtained in the step (1). The polylactic acid resin composition of layer P and the polylactic acid resin composition of layer Q obtained in step (2) are melt-coagulated so that layer P is at least one of the outermost layers on the front side and the back side of the sheet. Extrusion process

  The polylactic acid resin composition laminate sheet of the present invention has an excellent effect of achieving both high impact resistance and transparency.

  The polylactic acid resin composition laminate sheet of the present invention is obtained by laminating at least two layers of a polylactic acid resin composition containing a polylactic acid resin, a plasticizer, and an organic crystal nucleating agent, and one layer is the other. The plasticizer content is higher than that of the layer. Generally, a plasticizer is required according to the volume of the sheet that absorbs the impact in order to exert a relaxing action when an impact is applied from the outside. In a system in which the plasticizer is uniformly dispersed, the plasticizer according to the entire volume. A quantity is required. Then, transparency will fall over the whole sheet | seat. On the other hand, in the present invention in which there are a layer having a high plasticizer content and a layer having a low plasticizer content, a layer having a high plasticizer content is responsible for impact reduction from the outside. If the same amount as the amount of the agent is contained, the distribution ratio of the plasticizer is increased, and as a result, the impact resistance is considered to be improved. In addition, since the layer with less plasticizer can maintain the high transparency inherent in the polylactic acid resin, the transparency of the entire sheet is improved, and both impact resistance and transparency are achieved. Conceivable. However, these assumptions do not limit the present invention. In addition, the polylactic acid resin composition laminated sheet of the present invention may be simply referred to as the laminated sheet of the present invention.

<Polylactic acid resin composition laminated sheet>
The polylactic acid resin composition laminate sheet of the present invention includes at least a layer P and a layer Q described later, and includes a plurality of layers of the polylactic acid resin composition. Further, the layer P is disposed on at least one outermost layer on the front surface side and the back surface side of the sheet, preferably on each outermost layer on the front surface side and the back surface side, whereas the layer Q may be an inner layer, It is preferred that a layer Q exists between the layers P. For example, in the case of a three-layer structure, the layer Q is located at the center, and in the case of a five-layer structure, the layer Q can be arranged in any one other than the outermost layer. The number of laminated sheets is not particularly limited, but from the viewpoint of impact resistance and moldability, it is preferably 3 or more and 8 or less, more preferably 3 or more and 5 or less. For example, layer P / layer Q / It is a laminated sheet laminated in the order of layer P / layer Q / layer P and layer P / layer Q / layer P.

  In addition, the polylactic acid resin composition laminate sheet of the present invention may include a layer other than the layer P and the layer Q. For example, the polylactic acid resin composition laminate sheet of the present invention is placed on the subject. Examples include various release sheets such as a release sheet that can be peeled off or a sheet that imparts gas barrier properties or heat sealability to the polylactic acid resin composition laminate sheet of the present invention. Specifically, it is a sheet comprising a polyester resin composition such as PET, PBT or PTT, a polyolefin resin composition such as PE or PP, or a nylon resin composition as a constituent component. A well-known thing can be used for these functional sheets, According to the function, it can be laminated | stacked on the suitable position of the polylactic acid resin composition laminated sheet of this invention. For example, the release sheet can be attached to the outside of the polylactic acid resin composition laminate sheet of the present invention.

[Layer P]
The layer P in the present invention is a layer of a polylactic acid resin composition containing (PA) polylactic acid resin, (PB) plasticizer, and (PC) organic crystal nucleating agent, and is a plasticizer. The content of and the content of the organic crystal nucleating agent are the following contents.

[(PA) polylactic acid resin]
Examples of the polylactic acid resin in the layer P include commercially available polylactic acid resins such as those manufactured by Nature Works: Nature Works PLA / NW2003D, NW3001D, NW4032D, NW4060D, and Toyota Motor Corporation: Eco Plastic U'z S-09. In addition to S-12, S-17, and the like, polylactic acid resin synthesized from lactic acid or lactide can be used. Among them, from the viewpoint of improving the impact resistance and moldability of the polylactic acid resin composition of the layer P, a polylactic acid resin having an optical purity of preferably 90% or more, more preferably 95% or more is preferable. For example, Nature Works A polylactic acid resin (NW4032D or the like) manufactured by KK can be used. The optical purity of the polylactic acid in the present invention is D-containing as described in “Voluntary Standards for Food Containers and Packaging Made of Synthetic Resins such as Polyolefins, Third Edition, Revised June 2004, Part 3 Sanitation Test Method P12-13”. It can be determined according to the method of measuring the quantity.

  In the present invention, from the viewpoint of the strength and transparency of the polylactic acid resin composition, as the polylactic acid resin, a stereocomplex comprising two types of polylactic acid obtained by using lactic acid components mainly composed of different isomers. Polylactic acid resin may be used.

  In addition, the polylactic acid resin in the present invention may contain a biodegradable polyester resin other than the polylactic acid resin or a non-biodegradable resin such as polypropylene as a polymer alloy by blending with the polylactic acid resin. In the present specification, “biodegradable” means a property that can be decomposed into a low molecular weight compound by a microorganism in nature. Specifically, JIS K6953 (ISO 14855) “controlled aerobic composting conditions”. This means biodegradability based on the “Aerobic and Ultimate Biodegradation and Disintegration Test”.

  The content of the polylactic acid resin is preferably 80% by mass or more, more preferably 85% by mass or more, and preferably 98% by mass or less in the polylactic acid resin composition of the layer P from the viewpoint of impact resistance and transparency. 90 mass% or less is more preferable.

[(P-B) Plasticizer]
The plasticizer used in the layer P is one or more selected from the group consisting of the following (i) and (ii) from the viewpoint of improving impact resistance and transparency and improving moldability. It is preferable that an ester compound is included.
(I) An ester compound having two or more ester groups in the molecule, wherein at least one of the alcohol components constituting the ester compound has an average of 0.5 to 3 alkylene oxides per hydroxyl group. Ester compound which is an alcohol added to ˜8 mol, and (ii) Formula (I):
R ¹ O—CO—R ² —CO — [(OR ³ ) _m O—CO—R ² —CO—] _n OR ¹ (I)
(Wherein R ¹ is an alkyl group having 1 to 4 carbon atoms, R ² is an alkylene group having 2 to 4 carbon atoms, R ³ is an alkylene group having 2 or 3 carbon atoms, and m is 1 to 6) And n represents a number from 1 to 12, provided that all R ² may be the same or different, and all R ³ may be the same or different.
Compound represented by

  The ester compound (i) is an ester having 2 or more, preferably 2 or more and 5 or less, more preferably 2 or more and 3 or less in the molecule from the viewpoint of impact resistance, transparency, and moldability. An ester compound having a group, wherein at least one alcohol component constituting the ester compound is an average of 0.5 to 8 moles, preferably 1 mole or more of an alkylene oxide having 2 or 3 carbon atoms per hydroxyl group An ester compound which is an alcohol added with 6 mol or less, more preferably 1 mol or more and 3 mol or less can be used. Among them, preferably a polyhydric alcohol ester or a polycarboxylic acid ester having an ester group of 2 or more, preferably 2 or more and 5 or less, more preferably 2 or more and 3 or less in the molecule, At least one alcohol component constituting the ester compound is an average of 0.5 to 8 mol, preferably 1 to 6 mol, more preferably 1 mol of an alkylene oxide having 2 or 3 carbon atoms per hydroxyl group. An ester compound which is an alcohol added in an amount of 3 mol or less can be used.

  Specifically, for example, plasticizers described in JP 2008-174718 A and JP 2008-115372 A can be given. Of these, an average of 3 to 6 moles of an adduct of acetic acid and glycerin with an average of 3 to 6 moles of adduct (addition of 1 to 2 moles of ethylene oxide per hydroxyl group), an average number of moles of acetic acid and ethylene oxide added to 4 or more. Esters with 6 or less polyethylene glycol, esters with succinic acid and ethylene oxide having an average addition mole number of 2 to 6 polyethylene glycol monomethyl ether (addition of 2 to 6 moles of ethylene oxide per hydroxyl group), adipine An ester of an acid and diethylene glycol monomethyl ether and an ester of 1,3,6-hexanetricarboxylic acid and diethylene glycol monomethyl ether are preferably used.

  The ester compound (ii) is preferable from the viewpoint of impact resistance, transparency, and bleed resistance.

R ¹ in formula (I) represents an alkyl group having 1 to 4 carbon atoms, preferably 1 or 2, and is present in two molecules in one molecule and is present at both ends of the molecule. R ¹ may be linear or branched as long as it has 1 to 4 carbon atoms. Specific examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group and a tert-butyl group. A methyl group is preferable from the viewpoint of suppressing the out and from the viewpoint of impact resistance and transparency.

R ² in the formula (I) represents an alkylene group having 2 to 4 carbon atoms, and a linear alkylene group is a preferred example. Specific examples include an ethylene group, a 1,3-propylene group, and a 1,4-butylene group. Among them, the viewpoint of improving the compatibility with the polylactic acid resin and suppressing the bleed-out of the plasticizer, and the resistance to resistance. From the viewpoint of impact and transparency, an ethylene group and a 1,3-propylene group are preferable, and an ethylene group is more preferable. However, all R ² may be the same or different.

R ³ in formula (I) represents an alkylene group having 2 or 3 carbon atoms, and OR ³ represents an oxyalkylene group. Specific examples include an ethylene group, a 1,2-propylene group, and a 1,3-propylene group. However, all R ³ may be the same or different.

  m represents the average number of repeating oxyalkylene groups and is a number of 1 or more and 6 or less. When m increases, the ether group value of the ester compound represented by the formula (I) increases, which tends to be oxidized and the stability tends to decrease. From the viewpoint of improving the compatibility with the polylactic acid resin, the number is preferably 1 or more and 4 or less, more preferably 1 or more and 3 or less, and still more preferably 1 or more and 2 or less.

  n represents an average degree of polymerization and is a number of 1 or more and 12 or less. From the viewpoint of improving the compatibility with the polylactic acid resin and suppressing the bleeding out of the plasticizer, and from the viewpoint of impact resistance and transparency, the number of 1 or more and 4 or less is preferable, and the number of 1 or more and 3 or less is more preferable. A number of 1 or more and 2 or less is more preferable.

  Among such structures, from the viewpoint of transparency, at least one dibasic acid selected from succinic acid, glutaric acid, and adipic acid, diethylene glycol, triethylene glycol, 1,2-propanediol, and 1,3- At least one dihydric alcohol oligoester selected from propandiol (in formula (I), n = 1 to 3) is preferred.

  The compound represented by the formula (I) may be a commercially available product or may be synthesized according to a known production method, for example, produced according to a method disclosed in JP2012-62467A. be able to.

  In the present invention, plasticizers other than the above (i) and (ii) can be used within a range not impairing the effects of the present invention. Examples of the other plasticizers include polyester plasticizers, glycerin plasticizers, polycarboxylic acid ester plasticizers, polyalkylene glycol plasticizers, and epoxy plasticizers other than the above (i) and (ii). An agent or the like can be used. The content of one or more ester compounds selected from the group consisting of (i) and (ii) in the total plasticizer used in the present invention is 50% by mass from the viewpoint of impact resistance and transparency. The above is preferable, 70% by mass or more is more preferable, 90% by mass or more is further preferable, 95% by mass or more is further more preferable, and 100% by mass is even more preferable. In the present specification, the content of one or more ester compounds selected from the group consisting of (i) and (ii) means the total content when a plurality of compounds are used. .

  From the viewpoint of impact resistance, the content of the plasticizer in the layer P is preferably 5 parts by mass or more, more preferably 7 parts by mass or more, and 9 parts by mass or more with respect to 100 parts by mass of the polylactic acid resin of the layer P. Is more preferably 13 parts by mass or more, and preferably 20 parts by mass or less, more preferably 18 parts by mass or less, and still more preferably 17 parts by mass or less from the viewpoints of compatibility and moldability.

  Further, the content of the plasticizer in the polylactic acid resin composition of the layer P is 4% by mass or more and 18% by mass or less, but from the viewpoint of impact resistance, 6% by mass or more is preferable, and 8% by mass or more is preferable. More preferably, 10% by mass or more is further preferable, and from the viewpoint of transparency, 15% by mass or less is preferable, and 14% by mass or less is more preferable.

[(PC) Organic Crystal Nucleating Agent]
As the organic crystal nucleating agent used in the layer P, it is preferable to use at least one organic crystal nucleating agent selected from the group consisting of the following (a) to (d) from the viewpoint of transparency.
(A) From the group consisting of a compound having an isoindolinone skeleton, a compound having a diketopyrrolopyrrole skeleton, a compound having a benzimidazolone skeleton, a compound having an indigo skeleton, a compound having a phthalocyanine skeleton, and a compound having a porphyrin skeleton At least one organic compound selected [referred to as organic crystal nucleating agent (a)]
(B) At least one organic compound selected from the group consisting of carbohydrazides, uracils, and N-substituted ureas (referred to as organic crystal nucleating agent (b))
(C) at least one selected from the group consisting of metal salts of dialkyl aromatic sulfonates, metal salts of phosphoric acid esters, metal salts of phenylphosphonic acids, metal salts of rosin acids, aromatic carboxylic acid amides, and rosin acid amides Species of organic compound [referred to as organic crystal nucleating agent (c)]
(D) At least one organic compound selected from the group consisting of a compound having a hydroxyl group and an amide group in the molecule and a hydroxy fatty acid ester [referred to as organic crystal nucleating agent (d)]

  Among these, from the viewpoint of improving transparency, the organic crystal nucleating agent (c) and the organic crystal nucleating agent (d) are preferable, and the organic crystal nucleating agent (d) is more preferable.

  From the above viewpoint, the organic crystal nucleating agent (c) is preferably a phenylphosphonic acid metal salt having an optionally substituted phenyl group and a phosphonic group (—PO (OH) 2). Specific examples of these include unsubstituted phenylphosphonic acid, methylphenylphosphonic acid, ethylphenylphosphonic acid, propylphenylphosphonic acid, butylphenylphosphonic acid, dimethoxycarbonylphenylphosphonic acid, diethoxycarbonylphenylphosphonic acid, and the like. Unsubstituted phenylphosphonic acid is preferred.

  The compound having a hydroxyl group and an amide group in the molecule of the organic crystal nucleating agent (d) is preferably an aliphatic amide having a hydroxyl group. Specific examples thereof include hydroxy fatty acid monoamides such as 12-hydroxystearic acid monoethanolamide, methylenebis. Examples thereof include hydroxy fatty acid bisamides such as 12-hydroxystearic acid amide, ethylene bis 12-hydroxystearic acid amide, and hexamethylene bis 12-hydroxystearic acid amide.

  The content of the organic crystal nucleating agent in the layer P is preferably 0.1 parts by mass or more, from the viewpoint of improving the crystallinity of the sheet with respect to 100 parts by mass of the polylactic acid resin of the layer P, and is 0.3 mass. Part or more is more preferable, and from the viewpoint of transparency, 1.0 part by mass or less is preferable, 0.8 part by mass or less is more preferable, 0.75 part by mass or less is further preferable, and 0.5 part by mass or less is still more preferable. .

  The content of the organic crystal nucleating agent in the polylactic acid resin composition of the layer P is 0.05% by mass or more and 1.0% by mass or less, but from the viewpoint of improving the crystallinity, 0.1% by mass. % Or more, more preferably 0.2% by mass or more, and from the viewpoint of transparency, 0.9% by mass or less is preferable, and 0.5% by mass or less is more preferable.

[(PD) hydrolysis inhibitor]
From the viewpoint of improving impact resistance, the polylactic acid resin composition laminated sheet of the present invention can further contain a hydrolysis inhibitor in addition to the above components.

  Examples of the hydrolysis inhibitor include carbodiimide compounds such as polycarbodiimide compounds and monocarbodiimide compounds.

  Examples of monocarbodiimide compounds include diphenylcarbodiimide, di-2,6-dimethylphenylcarbodiimide, di-2,6-diethylphenylcarbodiimide, di-2,6-diisopropylphenylcarbodiimide, di-2,6-di-tert-butyl. Phenylcarbodiimide, di-o-tolylcarbodiimide, di-p-tolylcarbodiimide, di-2,4,6-trimethylphenylcarbodiimide, di-2,4,6-triisopropylphenylcarbodiimide, di-2,4,6- Aromatic monocarbodiimide compounds such as triisobutylphenylcarbodiimide; Alicyclic monocarbodiimide compounds such as di-cyclohexylcarbodiimide, di-cyclohexylmethanecarbodiimide; Di-isopropylcarbodiimide, di-octadecylca Aliphatic mono carbodiimide compounds such as Bojiimido like.

  Specific examples of the polycarbodiimide include poly (4,4′-diphenylmethanecarbodiimide), poly (p-phenylenecarbodiimide), poly (m-phenylenecarbodiimide), poly (diisopropylphenylcarbodiimide), and poly (triisopropylphenylcarbodiimide). ) And other alicyclic polycarbodiimides such as poly (dicyclohexylmethanecarbodiimide).

  You may use the said carbodiimide compound individually or in combination of 2 or more types. Among these, from the viewpoint of impact resistance, di-2,6-diisopropylphenylcarbodiimide and poly (dicyclohexylmethanecarbodiimide) are preferable, and di-2,6-diisopropylphenylcarbodiimide is more preferable.

  From the viewpoint of improving durability, the content of the hydrolysis inhibitor in the layer P is preferably 0.05 parts by mass or more, and 0.1 parts by mass or more with respect to 100 parts by mass of the polylactic acid resin of the layer P. More preferably, 0.3 parts by mass or more is more preferable, 3 parts by mass or less is preferable from the viewpoint of improving transparency, 2 parts by mass or less is more preferable, and 1 part by mass or less is still more preferable.

  The polylactic acid resin composition in the layer P includes lubricants, inorganic crystal nucleating agents, fillers (inorganic fillers, organic fillers), flame retardants, antioxidants, ultraviolet absorbers, antistatics as components other than those described above. An agent, an antifogging agent, a light stabilizer, a pigment, an antifungal agent, an antibacterial agent, a foaming agent, an impact modifier and the like can be contained within a range not impairing the effects of the present invention. Similarly, other polymer materials and other resin compositions can be contained within a range that does not impair the effects of the present invention. These amounts used can be appropriately set according to known techniques.

  The polylactic acid resin composition in the layer P can be prepared without particular limitation as long as it contains the components (PA) to (PC). For example, polylactic acid resin, plasticizer, and organic Using a known kneader such as a closed kneader, a single or twin screw extruder, an open roll kneader, and the like containing a crystal nucleating agent and, if necessary, other additives including a hydrolysis inhibitor. And can be prepared by melt-kneading. The raw materials can be subjected to melt kneading after being uniformly mixed in advance using a Henschel mixer, a super mixer, or the like. In preparing the polylactic acid resin composition, in order to promote the plasticity of the polylactic acid resin, it may be melt-mixed in the presence of a supercritical gas. After the melt-kneading, the melt-kneaded product may be dried according to a known method.

  The melt kneading temperature is preferably 170 ° C. or higher, preferably 220 ° C. or lower, more preferably 200 ° C. or lower, from the viewpoints of suppression of decomposition and transparency. The melt-kneading time cannot be generally determined depending on the melt-kneading temperature and the type of the kneader, but is preferably 15 seconds or more and 900 seconds or less.

  The polylactic acid resin composition in the layer P thus obtained can be layered (sheeted) according to a known method. In the present invention, the layer P and the layer Q may be separately formed and then laminated in the desired order, and the polylactic acid resin compositions of the layer P and the layer Q are laminated in the desired order. Things may be made into sheets at the same time. Details will be described later.

[Layer Q]
The layer Q in the present invention is a layer of a polylactic acid resin composition containing (QA) a polylactic acid resin, (QB) a plasticizer, and (QC) an organic crystal nucleating agent. The content of and the content of the organic crystal nucleating agent are the following contents.

[(Q-A) polylactic acid resin]
As the polylactic acid resin in the layer Q, the same polylactic acid resin as in the layer P can be used. Specifically, it is exemplified in the section of the polylactic acid resin in the layer P. Among them, from the viewpoint of improving the transparency of the polylactic acid resin composition of the layer Q, the optical purity is preferably 50% or more, more preferably 70% or more, still more preferably 80% or more, preferably 99% or less. A polylactic acid resin (NW2003D, 4032D, 4060D, etc.) manufactured by Nature Works, for example, can be used.

  From the viewpoint of impact resistance and transparency, the content of the polylactic acid resin is preferably 95% by mass or more, more preferably 100% by mass, and even more preferably 100% by mass in the polylactic acid resin composition of the layer Q. preferable. Here, “substantially 100% by mass” refers to the case of inevitably containing a trace amount of impurities.

[(Q-B) Plasticizer]
As the plasticizer in the layer Q, the same plasticizer as that in the layer P can be used. Specific examples include those exemplified in the section of the plasticizer in the layer P.

  The plasticizer content in the layer Q is preferably 6 parts by mass or less, more preferably 5 parts by mass or less, and more preferably 4 parts by mass or less from the viewpoint of transparency with respect to 100 parts by mass of the polylactic acid resin of the layer Q. More preferred is 3 parts by mass or less, still more preferred is 2 parts by mass or less. Although a minimum in particular is not set, it should just be 0 mass parts or more.

  The content of the plasticizer in the polylactic acid resin composition of the layer Q is 0% by mass or more and 6% by mass or less, but is preferably 5.4% by mass or less from the viewpoint of transparency, and is 5% by mass or less. Is more preferable, 4 mass% or less is further more preferable, and 3 mass% or less is still more preferable. In addition, in this specification, content of a plasticizer is 0 mass part or 0 mass% is an aspect in which a plasticizer is not contained in the polylactic acid resin composition in the layer Q. In the present invention, a layer A plasticizer may or may not be added to Q. In the present invention, the plasticizer component may be transferred from the layer P and may be recognized in the layer Q, so that the content is within the above range and the plasticizer content in the layer P is increased. Are included in the present invention.

  In the present invention, the plasticizer in the layer P and the plasticizer in the layer Q are characterized in that the plasticizer content in the layer P is large. When the content of the polylactic acid resin in the layer Q is used as a reference and compared with the content of 100 parts by mass of the polylactic acid resin in the layer Q, the content of the plasticizer in the layer P is the content of the plasticizer in the layer Q. Compared to the above, it is preferable that the amount is preferably 1 part by mass or more, more preferably 2 parts by mass or more. Also, no upper limit is set.

  Moreover, as total content of the plasticizer used for the laminated sheet of the present invention, when the total content of the polylactic acid resin in the laminated sheet is 100 parts by mass, 2 parts by mass or more is preferable, and 3 parts by mass or more is preferable. More preferably, 4.5 parts by mass or more is more preferable, 6 parts by mass or more is more preferable, 16 parts by mass or less is preferable, 12 parts by mass or less is more preferable, and 10 parts by mass or less is still more preferable. In the present invention, sufficient impact resistance can be obtained even when the total amount of plasticizer used is within the above range.

[(QC) Organic crystal nucleating agent]
As the organic crystal nucleating agent used in the layer Q, those similar to the organic crystal nucleating agent in the layer P can be used, and specifically, those exemplified in the section of the organic crystal nucleating agent in the layer P can be mentioned. It is done.

  The content of the organic crystal nucleating agent in the layer Q is preferably 0.9 parts by mass or less, more preferably 0.5 parts by mass or less, from the viewpoint of transparency with respect to 100 parts by mass of the polylactic acid resin of the layer Q. 0.2 parts by mass or less is more preferable. Although a minimum in particular is not set, it should just be 0 mass parts or more.

  Further, the content of the organic crystal nucleating agent in the polylactic acid resin composition of the layer Q is 0% by mass or more and 0.3% by mass or less, but from the viewpoint of transparency, 0.2% by mass or less is preferable, 0.1 mass% or less is more preferable. In the present specification, the content of the organic crystal nucleating agent is 0 part by mass or 0% by mass, which is an aspect in which the organic nucleating agent is not contained in the polylactic acid resin composition in the layer Q. In this case, an organic crystal nucleating agent may or may not be added to the layer Q. In the present invention, the organic crystal nucleating agent component may migrate from the layer P and be recognized in the layer Q, and any content within the above range is included in the present invention.

  The polylactic acid resin composition in the layer Q includes, as components other than the above, hydrolysis inhibitors, lubricants, inorganic crystal nucleating agents, fillers (inorganic fillers, organic fillers), flame retardants, antioxidants, ultraviolet rays It contains an absorbent, an antistatic agent, an antifogging agent, a light stabilizer, a pigment, an antifungal agent, an antibacterial agent, a foaming agent, an impact modifier, a crystallization inhibitor, and the like as long as the effects of the present invention are not impaired. Can do. Similarly, other polymer materials and other resin compositions can be contained within a range that does not impair the effects of the present invention. These amounts used can be appropriately set according to known techniques.

  Moreover, in this invention, it is preferable that the crystallinity of the polylactic acid resin in the layer Q is low from a viewpoint of improving the transparency of the layer Q. Therefore, for example, a crystallization inhibitor can be added to the polylactic acid resin composition in the layer Q. The crystallization inhibitor preferably has an acidic group from the viewpoint of interaction with polylactic acid, and is preferably amorphous or amorphous from the viewpoint of disturbing the higher-order structure of the polymer. From the viewpoint of properties, inorganic substances and / or polymers are preferable. Specifically, for example, a resin obtained by polymerizing one or more selected from aluminosilicate, silica, and (meth) acrylic acid, (meth) acrylic acid ester, and (meth) acrylic acid amide. Are preferred, and silica and polymethyl methacrylate are more preferred. Although it does not set in particular as content of a crystallization inhibitor, For example, 0.5 mass part or more and 25 mass parts or less are illustrated with respect to 100 mass parts of polylactic acid resin of the layer Q. Further, from the viewpoint of stability of the crystallization inhibition effect, in the case of an inorganic substance, it is preferably 0.5 parts by mass or more, more preferably 0.7 parts by mass or more with respect to 100 parts by mass of the polylactic acid resin of the layer Q. Yes, preferably 3 parts by mass or less, more preferably 1.3 parts by mass or less. In the case of a polymer, it is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, preferably 25 parts by mass or less, more preferably 22 parts by mass or less, relative to 100 parts by mass of the polylactic acid resin of the layer Q. It is.

  The polylactic acid resin composition in layer Q can be prepared without particular limitation as long as it contains the components (QA) to (QC), and is the same as the polylactic acid resin composition in layer P. Can be prepared. Specifically, the section of the method for preparing the polylactic acid resin composition in the layer P can be referred to.

  The polylactic acid resin composition in the layer Q thus obtained can be layered (made into a sheet) according to a known method. A known method can be selected as a method for laminating the layer P and the layer Q. Hereinafter, a method for simultaneously forming sheets of the polylactic acid resin compositions of the layer P and the layer Q in a desired order will be described.

  Specifically, for example, each of the polylactic acid resin compositions of the layer P and the layer Q is subjected to melt coextrusion molding using a T die such as a feed block method or a multi-manifold method to prepare a laminated sheet. be able to. Here, the crystallinity of the sheet may be adjusted by immediately contacting the obtained laminated sheet with a cooling roll and then a heating roll, and then cut. Moreover, you may uniaxially or biaxially stretch the obtained lamination sheet as needed. In addition, when filling an extruder, you may extrude after filling the raw material which comprises each polylactic acid resin composition, melt-kneading.

  The temperature of the extruder may be the same or different depending on the components of the polylactic acid resin composition of the layer P and the layer Q. Specifically, from the viewpoint of improving transparency, it is preferably 170 ° C. or higher, more preferably 175 ° C. or higher, further preferably 180 ° C. or higher, preferably 240 ° C. or lower, more preferably 220 ° C. or lower, still more preferably. It can set suitably within the temperature range of 210 degrees C or less. In addition, in this invention, the temperature of an extruder means the cylinder temperature of the biaxial kneading part of an extruder. Further, the residence time in the extruder cannot be defined unconditionally because it depends on the thickness, width, and winding speed of the sheet, but is preferably about 30 seconds to several minutes from the viewpoint of avoiding deterioration due to heat.

  The temperature of the cooling roll is preferably less than 40 ° C., more preferably 30 ° C. or less, from the viewpoint of improving transparency and improving peelability from the cooling roll.

  The time for contact with the cooling roll is not necessarily specified because it varies depending on the set temperature of the cooling roll, the number of cooling rolls, the extrusion speed, and the sheet winding speed. For example, it improves transparency and improves peelability from the cooling roll. From this point of view, it is preferably 1 second or longer, more preferably 3 seconds or longer, still more preferably 5 seconds or longer, preferably 60 seconds or shorter, more preferably 50 seconds or shorter, still more preferably 40 seconds or shorter.

  The surface temperature of the heating roll is preferably 65 ° C. or higher, more preferably 70 ° C. or higher, further preferably 75 ° C. or higher, and preferably 100 ° C. or lower, from the viewpoint of improving transparency and improving the crystallinity. The total time of contact with the heating roll is preferably 5 seconds or more, more preferably 10 seconds or more, and even more preferably 15 seconds or more. In addition, the surface temperature of a cooling roll and a heating roll means the temperature actually measured on the roll surface, and can be measured using a contact-type thermometer.

  Thus, the polylactic acid resin composition laminate sheet of the present invention is obtained. The thickness of the obtained laminated sheet is preferably 10 μm or more, more preferably 100 μm or more, preferably 1000 μm or less, more preferably 700 μm or less.

  Each layer in the laminated sheet includes, for example, a plurality of layers P, and the thickness of the thickest layer is preferably 5% or more, more preferably from the viewpoint of impact resistance with respect to the thickness of the entire laminated sheet. 7% or more, more preferably 11% or more, more preferably 15% or more. From the viewpoint of transparency, it is preferably 40% or less, more preferably 35% or less, still more preferably 28% or less, and still more preferably 24%. % Or less is preferable.

  Further, the ratio of the total thickness of the layer P to the thickness of the layer Q (layer P / layer Q) is preferably 80/20 to 10/90, and more preferably 55/45 to 30/70.

  When the thickness of the thickest one layer is 5% or more and 28% or less with respect to the total thickness of the laminated sheet, the content of the plasticizer in the layer P is in terms of impact resistance. To 6% by mass or more, more preferably 8% by mass or more, further preferably 10% by mass or more, and from the viewpoint of transparency, 15% by mass or less is preferable, and 14% by mass or less is more preferable.

  The thus obtained polylactic acid resin composition laminate sheet of the present invention has good transparency and excellent impact resistance, so that it can be used as a packaging material for various uses, for example, daily necessities, cosmetics, and home appliances. It can be suitably used as a material for trays, food containers such as lunch box lids, and industrial trays used for transportation and protection of industrial parts.

  This invention also provides the manufacturing method of the polylactic acid resin composition laminated sheet of this invention.

  As a manufacturing method, what is necessary is just a method including the process of melt-coextrusion molding the polylactic acid resin composition in the layer P and the polylactic acid resin composition in the layer Q. For example, the following methods are used suitably.

Specifically, the manufacturing method which has the following process (1)-(3) is mentioned.
Step (1): Polylactic acid resin constituting layer P by melting and kneading raw materials containing (PA) polylactic acid resin, (PB) plasticizer, and (PC) organic crystal nucleating agent In the step of preparing the composition, the content of the (P-B) plasticizer in the layer is 4% by mass or more and 18% by mass or less, and the content of the (PC) organic crystal nucleating agent is 0.00. Process step (2) which is not less than 05% by mass and not more than 1.0% by mass: A raw material containing (QA) polylactic acid resin, (QB) plasticizer, and (QC) organic crystal nucleating agent A step of preparing a polylactic acid resin composition constituting the layer Q by melt-kneading, wherein the content of the (Q-B) plasticizer in the layer is 0% by mass to 6% by mass, (Q -C) The content of the organic crystal nucleating agent is 0% by mass or more and 0.3% by mass or less,
Here, the content of the (P-B) plasticizer in the layer P is larger than the content of the (Q-B) plasticizer in the layer Q. The process step (3): obtained in the step (1). The polylactic acid resin composition of layer P and the polylactic acid resin composition of layer Q obtained in step (2) are melt-coagulated so that layer P is at least one of the outermost layers on the front side and the back side of the sheet. Extrusion process

  Step (1) includes (PA) polylactic acid resin, (PB) plasticizer, and (PC) organic crystal nucleating agent, and (PD) hydrolysis inhibitor as necessary. The raw materials containing other additives are preferably 170 ° C. or higher, preferably 220 ° C. or lower, using a known kneader such as a closed kneader, a single or twin screw extruder, and an open roll kneader. More preferably, the polylactic acid resin composition in the layer P is prepared by melt-kneading at a temperature of 200 ° C. or lower. The raw material and melt kneading conditions are in accordance with the term of the polylactic acid resin composition laminated sheet of the present invention.

  In step (2), a raw material containing (Q-A) polylactic acid resin, (Q-B) plasticizer, and (Q-C) organic crystal nucleating agent is used as a closed kneader, a single-screw or a twin-screw extruder. The polylactic acid resin in layer Q is melt kneaded at a temperature of preferably 170 ° C. or higher, preferably 220 ° C. or lower, more preferably 200 ° C. or lower, using a known kneader such as an open roll kneader. A composition is prepared. The raw material and melt kneading conditions are in accordance with the term of the polylactic acid resin composition laminated sheet of the present invention.

  In step (3), the polylactic acid resin composition obtained in step (1) and step (2) is melt-coextruded. As the melt coextrusion molding, it can be molded using a known melt coextrusion molding machine, and the conditions are appropriately set so that the layer P is at least one of the outermost layer on the front side and the back side of the sheet from which the layer P is obtained. can do. For example, when a melt coextrusion sheet forming machine (manufactured by Soken Co., Ltd., 300 mm T-die) equipped with a cooling roll and a heating roll is used, a laminated sheet with adjusted crystallinity can be obtained. The conditions for the extruder and the conditions for bringing it into contact with the subsequent cooling roll and heating roll are in accordance with the terms for the polylactic acid resin composition laminated sheet of the present invention.

The sheet after the melt coextrusion molding may be formed by cutting the end, and the cut end is mixed with the raw material of the polylactic acid resin composition constituting the layer P and / or the layer Q after melting. And it can be used as a polylactic acid resin composition of each layer. Especially, it is preferable to mix and use with the raw material of the polylactic acid resin composition which comprises the layer Q, and also as a further aspect of the manufacturing method of the polylactic acid resin composition laminated sheet of this invention, following process (4) ).
Step (4): A step of cutting a part of the melt-coextruded product obtained in Step (3) and then recovering and mixing it with the raw material of the polylactic acid resin composition in Step (2).

  In the step (4), the edge portion can be cut according to a known technique. As a ratio which cuts an edge part, from a viewpoint of productivity, 50 mass% or less of a polylactic acid resin composition lamination sheet is preferred, 40 mass% or less is more preferred, and 30 mass% or less is still more preferred.

  Hereinafter, the present invention will be specifically described with reference to examples. Note that this example is merely illustrative of the present invention and is not meant to be limiting. The parts in the examples are parts by mass unless otherwise specified. “Normal pressure” indicates 101.3 kPa, and “normal temperature” indicates 25 ° C.

Production Example 1 of Plasticizer ((MeEO ₃ ) ₂ SA, Diester Compound of Succinic Acid and Triethylene Glycol Monomethyl Ether)
In a 3 L flask equipped with a stirrer, a thermometer, and a dehydrating tube, 500 g of succinic anhydride, 2463 g of triethylene glycol monomethyl ether (manufactured by Wako Pure Chemical Industries, Ltd., reagent), paratoluenesulfonic acid monohydroxide (manufactured by Wako Pure Chemical Industries, Ltd., Reagent) (9.5 g) was charged and reacted at 110 ° C. for 15 hours under reduced pressure (4 to 10.7 kPa) while blowing nitrogen (500 mL / min) into the space. The acid value of the reaction solution was 1.6 mgKOH / g. After adding 27 g of adsorbent KYOWARD 500SH (manufactured by Kyowa Chemical Industry Co., Ltd.) to the reaction solution and stirring and filtering at 80 ° C. and 2.7 kPa for 45 minutes, triethylene at a liquid temperature of 115 to 200 ° C. and a pressure of 0.03 kPa. After distilling off the glycol monomethyl ether and cooling to 80 ° C., the residual liquid was filtered under reduced pressure to obtain a diester [(MeEO ₃ ) ₂ SA] of succinic acid and triethylene glycol monomethyl ether as a filtrate. The obtained diester had a weight average molecular weight of 410, a viscosity (23 ° C.) of 27 mPa · s, an acid value of 0.2 mgKOH / g, a saponification value of 274 mgKOH / g, a hydroxyl value of 1 mgKOH / g or less, and a hue APHA200. In addition, this plasticizer is an ester compound with the alcohol which added 3 mol of ethylene oxide per hydroxyl group.

Production Example 2 of Plasticizer ((MeEO ₄ ) ₂ SA, Diester Compound of Succinic Acid and Tetraethylene Glycol Monomethyl Ether)
A 3 L flask equipped with a stirrer, thermometer, and dehydration tube was charged with 500 g of succinic anhydride, 3124 g of tetraethylene glycol monomethyl ether, and 9.5 g of paratoluenesulfonic acid monohydroxide, and nitrogen (500 mL / min) was added to the space. While blowing, the reaction was carried out at 130 ° C. for 20 hours under reduced pressure (4 to 10.7 kPa). The acid value of the reaction solution was 1.6 mgKOH / g. After adding 27 g of adsorbent Kyoward 500SH to the reaction liquid and stirring and filtering at 80 ° C. and 2.7 kPa for 45 minutes, tetraethylene glycol monomethyl ether was distilled off at a liquid temperature of 150 to 250 ° C. and a pressure of 0.003 kPa. After cooling to 80 ° C., the residual liquid was filtered under reduced pressure to obtain a diester [(MeEO ₄ ) ₂ SA] of succinic acid and tetraethylene glycol monomethyl ether as a filtrate. The obtained diester had a weight average molecular weight of 499, a viscosity (23 ° C.) of 35 mPa · s, an acid value of 0.2 mgKOH / g, a saponification value of 225 mgKOH / g, a hydroxyl value of 1 mgKOH / g or less, and a hue of APHA230. In addition, this plasticizer is an ester compound with the alcohol which added 4 mol of ethylene oxide per hydroxyl group.

Production Example 3 of Plasticizer ((MeEO ₆ ) ₂ SA, Diester Compound of Succinic Acid and Hexaethylene Glycol Monomethyl Ether)
A 3 L flask equipped with a stirrer, thermometer, and dehydration tube was charged with 500 g of succinic anhydride, 4235 g of hexaethylene glycol monomethyl ether, and 9.5 g of paratoluenesulfonic acid monohydroxide, and nitrogen (500 mL / min) was added to the space. While blowing, the reaction was carried out at 150 ° C. under reduced pressure (4 to 10.7 kPa) for 40 hours. The acid value of the reaction solution was 1.6 mgKOH / g. After adding 27 g of adsorbent Kyoward 500SH to the reaction liquid and stirring and filtering at 80 ° C. and 2.7 kPa for 45 minutes, hexaethylene glycol monomethyl ether was distilled off at a liquid temperature of 200 to 280 ° C. and a pressure of 0.003 kPa. After cooling to 80 ° C., the remaining liquid was filtered under reduced pressure to obtain a diester [(MeEO ₆ ) ₂ SA] of succinic acid and hexaethylene glycol monomethyl ether as a filtrate. The obtained diester had a weight average molecular weight of 674, a viscosity (23 ° C.) of 42 mPa · s, an acid value of 0.2 mgKOH / g, a saponification value of 166 mgKOH / g, a hydroxyl value of 1 mgKOH / g or less, and a hue of APHA280. In addition, this plasticizer is an ester compound with the alcohol which added 6 mol of ethylene oxide per hydroxyl group.

Plasticizer Production Example 4 (MeSA-1,3PD, oligoester compound of dimethyl succinate and 1,3-propanediol)
A 4-throttle flask (with a stirrer, thermometer, dropping funnel, distillation tube, nitrogen blowing tube) was charged with 16.8 propanediol (1.84 mol) of 1,3-propanediol and 2.2 g of methanol solution containing 28 wt% sodium methoxide as a catalyst. (Sodium methoxide 0.011 mol) was added, and methanol was distilled off with stirring at normal pressure and 120 ° C. for 0.5 hour. Thereafter, 500 g (3.42 mol) of dimethyl succinate (manufactured by Wako Pure Chemical Industries, Ltd.) was dropped over 2 hours, and methanol produced by the reaction was distilled off at normal pressure and 120 ° C. Next, the mixture was cooled to 75 ° C., the pressure was gradually reduced from normal pressure to 6.7 kPa over 2 hours to distill off methanol, and the pressure was returned to normal pressure. Further, 28 wt% sodium methoxide-containing methanol was used as a catalyst. 2.0 g of solution (0.010 mol of sodium methoxide) was added, and methanol was distilled by gradually lowering the pressure from normal pressure to 2.9 kPa over 3 hours at 100 ° C. Then, after cooling to 80 ° C., 6 g of KYOWARD 600S (manufactured by Kyowa Chemical Industry Co., Ltd.) was added and stirred at a pressure of 4.0 kPa and 80 ° C. for 1 hour, followed by vacuum filtration. The filtrate was heated at a pressure of 4.5 kPa and the temperature was raised from 114 ° C. to 194 ° C. over 1 hour to distill off the remaining dimethyl succinate, thereby obtaining [MeSA-1, 3PD] as a yellow liquid at room temperature. In addition, the usage-amount of the catalyst was 0.61 mol with respect to 100 mol of dicarboxylic acid ester. The plasticizer is an ester compound represented by formula (I) (R ¹ is a methyl group, R ² is an ethylene group, R ³ is a propylene group, m is 1, and n is 1.5). .

Examples 1-17 and Comparative Examples 1-6
Preparation of polylactic acid resin composition in layer P As a polylactic acid resin composition, the composition raw materials shown in Tables 1 to 3 were mixed with a twin-screw extruder (Perker, HK25D, cylinder diameter 25.2 mm, rotation speed 100 rpm, discharge) The amount of 8 kg / h) was used for melt kneading at a melt kneading temperature of 180 to 190 ° C., and strand cutting was performed to obtain polylactic acid resin composition pellets. The obtained pellets were dried at 110 ° C. under reduced pressure for 2 hours, and the water content was adjusted to 500 ppm or less.

Preparation of a sheet-like molded body The pellets of the layer P obtained above and the pellets as the raw material of the layer Q were fed using a feed block type T-die extruder (manufactured by Soken Co., Ltd., 300 mm T-die) as follows. Under the conditions, 250 mm wide coextrusion sheet molding was performed to obtain a polylactic acid resin composition laminated sheet.
<Extrusion conditions>
Cylinder temperature of biaxial kneading part: 180 ° C
T-die (outlet) temperature: 200 ° C
Extrusion speed: 0.4 m / min (speed at which the heating roll contact time is 30 seconds)
Cooling roll surface temperature: 25 ° C
Heating roll surface temperature: 80 ° C
Sheet thickness: 300 μm

In addition, the raw material in Tables 1-3 is as follows.
<Polylactic acid resin>
4032D: Ingeo (registered trademark) Biopolymer 4032D manufactured by NatureWorks LLC (poly-L-lactic acid, optical purity 98.5%, melting point 166 ° C., weight average molecular weight 180000)
2003D: Ingeo (registered trademark) Biopolymer 2003D manufactured by NatureWorks LLC (poly-L-lactic acid, optical purity 95.7%, melting point 145 ° C., weight average molecular weight 200000)
4060D: Ingeo (registered trademark) Biopolymer 4060D manufactured by NatureWorks LLC (poly-L-lactic acid, optical purity 88.0%, no crystallization, no melting point measurement, weight average molecular weight 190000)
<Plasticizer>
DAIFATTY-101: a mixed diester of adipic acid and diethylene glycol monomethyl ether / benzyl alcohol = 1/1, manufactured by Daihachi Chemical Industry Co., Ltd.
(MeEO ₃ ) ₂ SA: Diester compound produced in Production Example 1 of the plasticizer
(MeEO ₄ ) ₂ SA: Diester compound produced in Production Example 2 of the plasticizer
(MeEO ₆ ) ₂ SA: Diester compound MeSA-1, 3PD produced in Production Example 3 of the plasticizer Oligoester compound Pluronic F68 produced in Production Example 4 of the plasticizer: Polyethylene glycol / polypropylene glycol copolymer, Made by ADEKA <impact modifier>
Puramate PD-350: PLA-aliphatic polyester copolymer, manufactured by DIC <organic crystal nucleating agent>
SLIPAX H: Ethylene bis 12-hydroxystearic acid amide, manufactured by Nippon Kasei Co., Ltd. <Hydrolysis inhibitor>
BioAdide 100: diisopropylphenylcarbodiimide, manufactured by Rhein Chemie <crystallization inhibitor>
Silicia 530: silica, average particle size 2.7 μm, silica content 99.8% by mass, Sumipex MGSV manufactured by Fuji Silysia Chemical Ltd .: polymethyl methacrylate resin, manufactured by Sumitomo Chemical Co., Ltd.

The characteristics of the obtained laminated sheet were evaluated according to the methods of Test Examples 1 and 2 below. The layer ratio was measured as follows. The results are shown in Tables 1-3.
<Layer ratio>
The resin used for the inner layer is colored with a black pigment (carbon black), and a fracture surface of the obtained laminated sheet is prepared using a microtome, and is used at 200 times using an optical microscope (VHX-1000, manufactured by Keyence Corporation). Observation was made, the sheet thickness and the thickness of the inner colored layer were measured, and the layer ratio was determined.

Test Example 1 <Transparency>
A sample of 5 cm × 5 cm × 0.3 mm was prepared from the molded sheet, and the haze value was measured using an integrating sphere type light transmittance measuring device (HM-150 Murakami Color Research Laboratory) defined in JIS-K7105. It shows that transparency is so favorable that the value of Haze value is small.

Test example 2 <impact resistance>
A sample of 5 cm × 5 cm × 0.3 mm was prepared from the molded sheet, and a DuPont type drop impact tester (manufactured by Yasuda Seiki Seisakusho, No.517-L, a maximum drop height of 1000 mm, an interval of 50 mm, a diameter of 19.05 mm) 50% impact fracture energy measured in an atmosphere at a temperature of 23 ° C. according to JIS-K7211-1 (2006) using a shooting mold, a cradle with a diameter of 19.05 mm, and a drop weight of 100 to 1000 g) was defined as impact strength. . It shows that it is excellent in impact resistance, so that the numerical value of impact strength is large.

  From Tables 1-3, it turns out that the polylactic acid resin composition laminated sheet of an Example is excellent in both impact resistance and transparency. Moreover, when Examples 2-4 and 6 and Comparative Examples 1-4 in which the same content is mix | blended as the plasticizer content in the whole sheet | seat are contrasted, the laminated sheet of an Example is compared with the sheet | seat of a comparative example. It is highly transparent and has excellent impact resistance. On the other hand, Comparative Example 6 using a conventionally used impact modifier was lower in transparency and inferior in impact resistance than the polylactic acid resin composition laminated sheet of the present invention.

  Moreover, it turns out that transparency improves markedly by mix | blending a crystallization inhibitor with the layer Q by contrast of Examples 15-17, improving or maintaining impact resistance.

  Since the polylactic acid resin composition laminate sheet of the present invention is excellent in transparency and impact resistance, it should be used suitably for various applications such as food containers, packaging materials for household goods and household appliances, trays for industrial parts, etc. Can do.

Claims (6)

A polylactic acid resin composition laminate sheet comprising a plurality of polylactic acid resin composition layers, and a polylactic acid resin composition laminate sheet comprising at least the next layer P and layer Q,
Layer P is a layer of a polylactic acid resin composition containing (P-A) polylactic acid resin, (P-B) plasticizer, and (P-C) organic crystal nucleating agent, and (P- B) The content of the plasticizer is 4% by mass or more and 18% by mass or less, and the content of the (PC) organic crystal nucleating agent is 0.05% by mass or more and 1.0% by mass or less,
Layer Q is a layer of a polylactic acid resin composition containing (QA) polylactic acid resin, (QB) plasticizer, and (QC) organic crystal nucleating agent, and (Q- B) The content of the plasticizer is 0% by mass or more and 6% by mass or less, and the content of the (QC) organic crystal nucleating agent is 0% by mass or more and 0.3% by mass or less.
Here, the content of the (P-B) plasticizer in the layer P is greater than the content of the (Q-B) plasticizer in the layer Q, and at least one of the outermost layers on the front and back sides of the sheet Is a polylactic acid resin composition laminate sheet in which layer P is.   2. The polylactic acid resin composition according to claim 1, comprising a plurality of layers P, wherein the thickness of the thickest one of the layers P is 5% or more and 40% or less with respect to the thickness of the polylactic acid resin composition laminate sheet. Laminated sheet.   The polylactic acid resin composition laminated sheet according to claim 1 or 2, comprising a plurality of layers P, wherein a layer Q is laminated between at least two layers P. (PB) plasticizer and / or (QB) plasticizer,
(I) An ester compound having two or more ester groups in the molecule, wherein at least one of the alcohol components constituting the ester compound has an average of 0.5 to 3 alkylene oxides per hydroxyl group. Ester compound which is an alcohol added to ˜8 mol, and (ii) Formula (I):
R ¹ O—CO—R ² —CO — [(OR ³ ) _m O—CO—R ² —CO—] _n OR ¹ (I)
(Wherein R ¹ is an alkyl group having 1 to 4 carbon atoms, R ² is an alkylene group having 2 to 4 carbon atoms, R ³ is an alkylene group having 2 or 3 carbon atoms, and m is 1 to 6) And n represents a number from 1 to 12, provided that all R ² may be the same or different, and all R ³ may be the same or different.
The polylactic acid resin composition laminated sheet according to any one of claims 1 to 3, comprising one or more selected from the group consisting of compounds represented by: A method for producing a polylactic acid resin composition laminated sheet comprising a plurality of polylactic acid resin composition layers, comprising the following steps (1), (2) and (3).
Step (1): Polylactic acid resin constituting layer P by melting and kneading raw materials containing (PA) polylactic acid resin, (PB) plasticizer, and (PC) organic crystal nucleating agent In the step of preparing the composition, the content of the (P-B) plasticizer in the layer is 4% by mass or more and 18% by mass or less, and the content of the (PC) organic crystal nucleating agent is 0.00. Process step (2) which is not less than 05% by mass and not more than 1.0% by mass: A raw material containing (QA) polylactic acid resin, (QB) plasticizer, and (QC) organic crystal nucleating agent A step of preparing a polylactic acid resin composition constituting the layer Q by melt-kneading, wherein the content of the (Q-B) plasticizer in the layer is 0% by mass to 6% by mass, (Q -C) The content of the organic crystal nucleating agent is 0% by mass or more and 0.3% by mass or less,
Here, the content of the (P-B) plasticizer in the layer P is larger than the content of the (Q-B) plasticizer in the layer Q. The process step (3): obtained in the step (1). The polylactic acid resin composition of layer P and the polylactic acid resin composition of layer Q obtained in step (2) are melt-coagulated so that layer P is at least one of the outermost layers on the front side and the back side of the sheet. Extrusion process Furthermore, the manufacturing method of Claim 5 including the following process (4).
Step (4): A step of cutting a part of the melt-coextruded product obtained in Step (3) and then recovering and mixing it with the raw material of the polylactic acid resin composition in Step (2).