JP6942046B2 - Polylactic acid resin composition laminated sheet - Google Patents

Description

The present invention relates to a laminated sheet of polylactic acid resin composition. 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 for daily necessities, cosmetics, home appliances, etc., and a method for producing the sheet.

Polylactic acid resin is expected to be used because its raw material is derived from plants and therefore emits extremely little carbon dioxide. However, due to its characteristics such as high rigidity and high transparency, it is laminated. A technique for imparting functionality through conversion is being studied.

For example, Patent Document 1 describes a layer P containing a plasticizer and a layer Q having a lower plasticizer content than the layer P as a laminated sheet of a polylactic acid resin composition having both high impact resistance and transparency. A provided laminated sheet of polylactic acid resin composition has been proposed.

JP-A-2017-24407

However, in the polylactic acid resin composition laminated sheet of Patent Document 1, the transparency may be deteriorated during storage, and it has been found that further improvement is required.

The present invention relates to a polylactic acid resin composition laminated sheet having excellent transparency and storage stability, 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 containing a plurality of layers of a polylactic acid resin composition, and a polylactic acid resin composition laminated sheet containing at least the following layers P and Q.
Layer P is a layer of a polylactic acid resin composition containing (PA) polylactic acid resin, (P-B) plasticizer, and (PC) organic crystal nucleating agent.
Layer Q is a layer of the polylactic acid resin composition containing the (QA) polylactic acid resin and the (QC) organic crystal nucleating agent, and the layer contains the (QC) organic crystal nucleating agent. The amount is more than 0.3% by mass and 1.0% by mass or less.
Here, when the layer Q further contains the (Q-B) plasticizer, the content of the (P-B) plasticizer in the layer P is higher than that of the (Q-B) plasticizer in the layer Q. A laminated sheet of a polylactic acid resin composition having a content higher than that of the sheet, wherein at least one outermost layer on the front surface side and the back surface side is the layer P.
[2] A method for producing a polylactic acid resin composition laminated sheet containing a plurality of layers of a polylactic acid resin composition, which comprises the following steps (1), (2), and (3). Sheet manufacturing method.
Step (1): Polylactic acid resin constituting layer P by melt-kneading a raw material containing (PA) polylactic acid resin, (P-B) thermoplastic, and (PC) organic crystal nucleating agent. Steps for preparing the composition Step (2): Polylactic acid resin composition containing (QA) polylactic acid resin and (QC) organic crystal nucleating agent is melt-kneaded to form layer Q. The content of the (QC) organic crystal nucleating agent in the layer is more than 0.3% by mass and 1.0% by mass or less in the step of preparing.
Here, when the layer Q further contains the (Q-B) plasticizer, the content of the (P-B) plasticizer in the layer P is higher than that of the (Q-B) plasticizer in the layer Q. Steps greater than the content Step (3): The layer P is a sheet of the layer P polylactic acid resin composition obtained in the step (1) and the layer Q polylactic acid resin composition obtained in the step (2). A step of melt coextrusion molding so as to be the outermost layer of at least one of the front surface side and the back surface side of the

According to the present invention, it is possible to provide a polylactic acid resin composition laminated sheet having excellent transparency and storage stability, and a method for producing the laminated sheet.

The polylactic acid resin composition laminated 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. It is characterized by having a higher content of plasticizer than the layer of. In general, a plasticizer is required according to the volume of the sheet that absorbs the impact in order to exert a relaxing effect when an impact is applied from the outside. However, in a system in which the plasticizer is uniformly dispersed, the plasticizer according to the total volume. Amount is needed. Then, the transparency and the rigidity are reduced over the entire sheet. On the other hand, in the present invention in which a layer having a high plasticizer content (also referred to as layer P) and a layer having a low plasticizer content (also referred to as layer Q) exist, the external impact mitigation is carried out by the layer P having a high plasticizer content. If the layer contains the same amount of the plasticizer required in the uniform dispersion system, the distribution ratio of the plasticizer will increase, and as a result, the impact resistance will be improved. In addition, since the layer Q with less plasticizer can maintain the high transparency and rigidity inherent in the polylactic acid resin, the transparency of the entire sheet is also improved, and both impact resistance and transparency are achieved. It is believed that it will be done.

Here, in the layer Q having a small amount of plasticizer, it is considered desirable to lower the crystallinity from the viewpoint of improving the transparency. Therefore, conventionally, it has been considered desirable to reduce the amount of the plasticizer and the organic crystal nucleating agent in the layer Q as much as possible. In fact, in the examples of Patent Document 1, high transparency is obtained in a mode in which the layer Q does not contain a plasticizer or an organic crystal nucleating agent. However, when the present inventors examined the above-mentioned problems, surprisingly, by containing a specific amount of the organic crystal nucleating agent in the layer Q having a small amount of plasticizer, not only the transparency was excellent, but also the glass transition point or higher. We have newly found that it is possible to maintain transparency during storage at the same temperature and that it is also excellent in storage stability. Although this mechanism is not clear, by microcrystallizing the layer Q within a range that does not deteriorate the transparency, it is possible to prevent the transfer and diffusion of the plasticizer from the layer P having a high plasticizer content to the layer Q. It is presumed that this is because the crystallization of the layer Q caused by this can be suppressed. However, these speculations do not limit the present invention. 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 laminated sheet of the present invention contains at least layers P and Q, which will be described later, and includes a plurality of layers of the polylactic acid resin composition. Further, the layer P is arranged 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 preferable that the layer Q is present 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 of the outermost layers. The number of laminated sheets is not particularly limited, but from the viewpoint of impact resistance and moldability, it is preferably 3 layers or more and 8 layers or less, more preferably 3 layers or more and 5 layers 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 in the order of layer P / layer Q / layer P.

The polylactic acid resin composition laminated sheet of the present invention may include layers other than the layer P and the layer Q. For example, the polylactic acid resin composition laminated sheet of the present invention is placed on the target. Examples thereof include various functional sheets such as a release sheet that can be peeled off at the time, or a sheet that imparts gas barrier property or heat seal property to the polylactic acid resin composition laminated sheet of the present invention. Specifically, it is a sheet containing 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 constituent components. Known functional sheets can be used, and the polylactic acid resin composition laminated sheet of the present invention can be laminated at an appropriate position according to its function. For example, the release sheet can be attached to the outside of the polylactic acid resin composition laminated 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, (P-B) plasticizer, and (PC) organic crystal nucleating agent.

[(PA) Polylactic acid resin]
Examples of the polylactic acid resin in the layer P include commercially available polylactic acid resins, for example, Nature Works PLA / NW2003D, NW3001D, NW4032D, NW4060D, and Toyota Motor Corporation: Ecoplastic U'z S-09. , S-12, S-17 and the like, as well as polylactic acid resins synthesized from lactic acid and lactide. Among them, from the viewpoint of improving the impact resistance and moldability of the polylactic acid resin composition of layer P, a polylactic acid resin having an optical purity of preferably 90% or more, more preferably 95% or more is preferable, and for example, Nature Works. A company-made polylactic acid resin (NW4032D or the like) can be used. The optical purity of polylactic acid in the present invention is the D-form content described in "Voluntary Standards for Food Containers and Packaging Made of Synthetic Resins such as Polyolefins, 3rd Edition, Revised Edition, June 2004 Supplement, Part 3 Hygiene Test Method P12-13". It can be determined according to the method for measuring the amount.

Further, in the present invention, as the polylactic acid resin, a stereo complex composed of two types of polylactic acid obtained by using lactic acid components containing different isomers as main components from the viewpoint of strength and transparency of the polylactic acid resin composition. Polylactic acid resin may be used.

Further, the polylactic acid resin in the present invention may contain a biodegradable polyester resin other than the polylactic acid resin and a non-biodegradable resin such as polypropylene as a polymer alloy by blending with the polylactic acid resin. In addition, in this specification, "biodegradability" is a property that can be decomposed into a low molecular weight compound by a microorganism in the natural world. Specifically, JIS K6953 (ISO14855) "Controlled aerobic composting condition". It means biodegradability based on the aerobic and ultimate biodegradability and disintegration degree 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. More preferably, it is 90% by mass or less.

[(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 preferably contains an ester compound.
(I) An ester compound having two or more ester groups in the molecule, and at least one of the alcohol components constituting the ester compound contains an average of 0.5 alkylene oxide having 2 to 3 carbon atoms per hydroxyl group. Ester compounds that are alcohols with ~ 8 mol added, and formula (I):
R ¹ O-CO-R ² -CO-[(OR ³ ) _m O-CO-R ^2- CO-] _n OR ¹ (I)
(In the formula, 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 , N indicates a number from 1 to 12, but all R ^2s may be the same or different, and all R ^3s may be the same or different).
Compound represented by

As the ester compound of (i), from the viewpoint of impact resistance, transparency, and moldability, 2 or more, preferably 2 or more and 5 or less, more preferably 2 or more and 3 or less esters in the molecule. An ester compound having a group, wherein at least one of the alcohol components constituting the ester compound contains an average of 0.5 mol or more and 8 mol or less, preferably 1 mol or more, of an alkylene oxide having 2 or 3 carbon atoms per hydroxyl group. Ester compounds which are alcohols added in an amount of 6 mol or less, more preferably 1 mol or more and 3 mol or less can be used. Among them, a polyhydric alcohol ester or a polyvalent carboxylic acid ester having two or more, preferably two or more and five or less, more preferably two or more and three or less ester groups in the molecule is preferable. At least one of the alcohol components constituting the ester compound contains an average of 0.5 mol or more and 8 mol or less, preferably 1 mol or more and 6 mol or less, and 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.

Specific examples thereof include the plasticizers described in JP-A-2008-174718 and JP-A-2008-115372. Among them, the average number of molar additions of ethylene oxide of acetic acid and glycerin is 3 mol or more and 6 mol or less (addition of 1 mol or more and 2 mol or less of ethylene oxide per hydroxyl group), and the average number of moles of acetic acid and ethylene oxide is 4 or more. Ester with 6 or less polyethylene glycol, ester with polyethylene glycol monomethyl ether with an average addition molar number of succinic acid and ethylene oxide of 2 or more and 6 or less (addition of 2 mol or more and 6 mol or less 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 of (ii) is preferable from the viewpoint of impact resistance, transparency, and bleed resistance.

^{R 1} in the formula (I) represents an alkyl group having 1 or more and 4 or less carbon atoms, preferably 1 or 2, and is present in two in one molecule and is present at both ends of the molecule. R ¹ may be a straight chain or a branched chain as long as it has 1 or more and 4 or less carbon atoms. Specific examples thereof 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. Among them, bleeding of a plastic agent by improving compatibility with a polylactic acid resin. A methyl group is preferable from the viewpoint of suppressing out-out, and from the viewpoint of impact resistance and transparency.

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

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

m represents the average number of repetitions of the oxyalkylene group, and is a number of 1 or more and 6 or less. As m increases, the ether base value of the ester compound represented by the formula (I) increases, and it tends to be easily oxidized and the stability tends to decrease. From the viewpoint of improving compatibility with the polylactic acid resin, a number of 1 or more and 4 or less is preferable, a number of 1 or more and 3 or less is more preferable, and a number of 1 or more and 2 or less is further preferable.

n indicates the average degree of polymerization and is a number of 1 or more and 12 or less. From the viewpoint of improving compatibility with the polylactic acid resin and suppressing bleed-out of the plasticizer, and from the viewpoint of impact resistance and transparency, a number of 1 or more and 4 or less is preferable, and a 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-. Oligoesters of at least one dihydric alcohol selected from propandiol [n = 1-3 in formula (I)] are preferred.

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

In the present invention, other plasticizers other than the above (i) and (ii) can be used as long as the effects of the present invention are not impaired. Examples of other plasticizers include polyester-based plasticizers, glycerin-based plasticizers, polyvalent carboxylic acid ester-based plasticizers, polyalkylene glycol-based plasticizers, and epoxy-based plasticizers other than the above (i) and (ii). Agents and 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 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. ..

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 from the viewpoint of impact resistance. Is more preferable, 13 parts by mass or more is further preferable, 20 parts by mass or less is preferable, 18 parts by mass or less is more preferable, and 17 parts by mass or less is further preferable from the viewpoint of compatibility and moldability.

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

[(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 carbhydrazides, uracils, and N-substituted ureas [referred to as organic crystal nucleating agent (b)].
(C) At least one selected from the group consisting of a metal salt of dialkyl aromatic sulfonic acid, a metal salt of phosphoric acid ester, a metal salt of phenylphosphonic acid, a metal salt of logonic acids, an aromatic carboxylic acid amide, and a loginic acid amide. Species of organic compounds [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 an organic crystal nucleating agent (d)].

Among these, 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 viewpoint of improving transparency.

From the above viewpoint, the organic crystal nucleating agent (c) is preferably a metal salt of phenylphosphonic acid having a phenyl group which may have a substituent and a phosphon group (-PO (OH) 2), and phenylphosphonic acid. Specific examples of the above include unsubstituted phenylphosphonic acid, methylphenylphosphonic acid, ethylphenylphosphonic acid, propylphenylphosphonic acid, butylphenylphosphonic acid, dimethoxycarbonylphenylphosphonic acid, diethoxycarbonylphenylphosphonic acid and the like. Unsubstituted phenylphosphonic acid is preferred.

As the compound having a hydroxyl group and an amide group in the molecule of the organic crystal nucleating agent (d), an aliphatic amide having a hydroxyl group is preferable, and specific examples thereof include hydroxy fatty acid monoamides such as 12-hydroxystearic acid monoethanolamide and methylenebis. Examples thereof include hydroxy fatty acid bisamides such as 12-hydroxystearic acid amide, ethylenebis 12-hydroxystearic acid amide, and hexamethylenebis 12-hydroxystearic acid amide.

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

The content of the organic crystal nucleating agent in the polylactic acid resin composition of layer P is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and 0, from the viewpoint of improving the degree of crystallization. .2% by mass or more is more preferable, and from the viewpoint of transparency, 1.0% by mass or less is more preferable, 0.9% by mass or less is more preferable, and 0.5% by mass or less is further preferable.

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

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, and 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 and di-cyclohexylmethanecarbodiimide; aliphatic monocarbodiimide compounds such as di-isopropylcarbodiimide and di-octadecylcarbodiimide. Be done.

Specific examples of the polycarbodiimide include poly (4,4'-diphenylmethanecarbodiimide), poly (p-phenylene carbodiimide), poly (m-phenylene carbodiimide), poly (diisopropylphenylcarbodiimide), and poly (triisopropylphenylcarbodiimide). ) And other aromatic polycarbodiimides; examples thereof include alicyclic polycarbodiimides such as poly (dicyclohexylmethanecarbodiimide).

The carbodiimide compound may be used alone or in combination of two or more. Among these, di-2,6-diisopropylphenylcarbodiimide and poly (dicyclohexylmethanecarbodiimide) are preferable, and di-2,6-diisopropylphenylcarbodiimide is more preferable from the viewpoint of impact resistance.

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

The polylactic acid resin composition in the layer P has, as other components other than the above, a lubricant, an inorganic crystal nucleating agent, a filler (inorganic filler, an organic filler), a flame retardant, an antioxidant, an ultraviolet absorber, and an antistatic agent. Agents, antifogging agents, light stabilizers, pigments, fungicides, antibacterial agents, foaming agents, impact improvers and the like can be contained within a range that does not impair 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. The amount of these used can be appropriately set according to a known technique.

The polylactic acid resin composition in the layer P can be prepared without particular limitation as long as it contains the above-mentioned components (PA) to (PC). For example, a polylactic acid resin, a plasticizer, and an organic material can be prepared. A known kneader such as a closed kneader, a single-screw extruder, or an open-roll kneader is used as a raw material containing a crystal nucleating agent and, if necessary, other additives including a hydrolysis inhibitor. It can be prepared by melting and kneading. The raw materials can be uniformly mixed in advance using a Henschel mixer, a super mixer, or the like, and then subjected to melt-kneading. In addition, in order to promote the plasticity of the polylactic acid resin when preparing the polylactic acid resin composition, a supercritical gas may be present and melt-mixed. 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, and more preferably 200 ° C. or lower, from the viewpoint of suppressing decomposition and transparency. The melt-kneading time cannot be unconditionally determined depending on the melt-kneading temperature and the type of kneading machine, 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 sheeted and then laminated in a desired order, or the polylactic acid resin compositions of the layer P and the layer Q are laminated in a desired order. You may make things 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 and (QC) an organic crystal nucleating agent, and the content of the organic crystal nucleating agent is as follows. It is characterized by having a content.

[(QA) 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 polylactic acid resin in layer P. Among them, from the viewpoint of improving the transparency of the polylactic acid resin composition of layer Q, the optical purity is preferably 50% or more, more preferably 70% or more, further preferably 80% or more, and preferably 99% or less. Polylactic acid resin is preferable, and for example, polylactic acid resin manufactured by Nature Works (NW2003D, 4032D, 4060D, etc.) can be used.

The content of the polylactic acid resin is preferably 95% by mass or more, more preferably 99% by mass or more in the polylactic acid resin composition of the layer Q from the viewpoint of rigidity and transparency.

[(Q-B) Plasticizer]
A plasticizer may be further contained in the layer Q. As the plasticizer in the layer Q, the same one as the plasticizer in the layer P can be used, and specific examples thereof include those exemplified in the section of the plasticizer in the layer P.

The content of the plasticizer in the layer Q is preferably 6 parts by mass or less, more preferably 5 parts by mass or less, and 4 parts by mass or less with respect to 100 parts by mass of the polylactic acid resin of the layer Q from the viewpoint of transparency. More preferably, 3 parts by mass or less is further preferable, and 2 parts by mass or less is even more preferable. The lower limit is not particularly set, but it may be 0 parts by mass or more.

The content of the plasticizer in the polylactic acid resin composition of layer Q is 0% by mass or more and 6% by mass or less, but from the viewpoint of transparency, it is preferably 5.4% by mass or less, and 5% by mass or less. Is more preferable, 4% by mass or less is further preferable, and 3% by mass or less is further preferable. In the present specification, the content of the plasticizer is 0 parts by mass or 0% by mass means that the polylactic acid resin composition in the layer Q does not contain the plasticizer, and in the present invention, the layer A plasticizer may or may not be added to Q. Further, in the present invention, the plasticizer component may be transferred from the layer P and recognized in the layer Q, and the content is within the above range and the plasticizer content in the layer P is increased. For example, it is included in the present invention.

In the present invention, when the layer Q further contains a plasticizer, one of the features is that the plasticizer in the layer P and the plasticizer in the layer Q have a large content of the plasticizer in the layer P. .. When compared as the content of the polylactic acid resin in the layer Q with respect to 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. It is preferable that the amount is 1 part by mass or more, more preferably 2 parts by mass or more. In addition, no upper limit is set.

The total content of the plasticizer used in the laminated sheet of the present invention is preferably 2 parts by mass or more, preferably 3 parts by mass or more, when the total content of the polylactic acid resin in the laminated sheet is 100 parts by mass. More preferably, 4.5 parts by mass or more is further preferable, 6 parts by mass or more is further 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 further preferable. In the present invention, sufficient impact resistance can be obtained even if the total amount of the plasticizer used is within the above range.

[(QC) Organic Crystal Nucleating Agent]
As the organic crystal nucleating agent used in the layer Q, the same organic crystal nucleating agent as in the layer P can be used, and specific examples thereof include those exemplified in the section of the organic crystal nucleating agent in the layer P. However, from the viewpoint of storage stability, the above-mentioned organic crystal nucleating agent (d) and the like are preferable.

The content of the organic crystal nucleating agent in the layer Q is preferably 0.32 parts by mass or more, more preferably 0.35 parts by mass or more, with respect to 100 parts by mass of the polylactic acid resin of the layer Q from the viewpoint of storage stability. It is preferably 0.40 parts by mass or more, more preferably 1.00 parts by mass or less, more preferably 0.90 parts by mass or less, and further preferably 0.80 parts by mass or less from the viewpoint of transparency.

The content of the organic crystal nucleating agent in the polylactic acid resin composition of layer Q exceeds 0.3% by mass and is 1% by mass or less, but from the viewpoint of storage stability, it is 0.32% by mass or more. Is preferable, 0.35% by mass or more is more preferable, 0.40% by mass or more is further preferable, and from the viewpoint of transparency, 1.00% by mass or less is preferable, 0.90% by mass or less is more preferable, and 0. More preferably, it is 80% by mass or less. Further, in the present invention, the organic crystal nucleating agent component may be transferred from the layer P and recognized in the layer Q, and if the content is within the above range, it is included in the present invention.

The crystallinity of the layer Q is preferably 5% or more, more preferably 7% or more, still more preferably 10% or more from the viewpoint of storage stability.

The polylactic acid resin composition in layer Q has, as other components other than the above, a hydrolysis inhibitor, a lubricant, an inorganic crystal nucleating agent, a filler (inorganic filler, an organic filler), a flame retardant, an antioxidant, and ultraviolet rays. Absorbents, antistatic agents, antifogging agents, light stabilizers, pigments, fungicides, antibacterial agents, foaming agents, impact improvers and the like can be contained within a range that does not impair 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. The amount of these used can be appropriately set according to a known technique.

The polylactic acid resin composition in layer Q is not particularly limited as long as it contains the components (QA) and (QC), and if necessary, further contains the component (QB). It can be prepared and can be prepared in the same manner as the polylactic acid resin composition in layer P. 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 (sheeted) according to a known method. A known method can be selected for the method of laminating the layer P and the layer Q, but a method of simultaneously forming the polylactic acid resin compositions of the layer P and the layer Q into sheets in a desired order will be described below.

Specifically, for example, a laminated sheet is prepared by subjecting each of the polylactic acid resin compositions of layer P and layer Q to melt coextrusion molding using a T die such as a feed block method or a multi-manifold method. be able to. Here, the crystallinity of the sheet may be adjusted by bringing the obtained laminated sheet into contact with a cooling roll and then a heating roll, and then cutting may be performed. Further, the obtained laminated sheet may be uniaxially or biaxially stretched as required. When filling the extruder, the raw materials constituting each polylactic acid resin composition may be filled, melt-kneaded, and then extruded.

The temperature of the extruder may be the same or different depending on the constituents of the polylactic acid resin composition of layer P and 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 be appropriately set within a temperature range of 210 ° C. or lower. In the present invention, the temperature of the extruder means the cylinder temperature of the twin-screw kneaded portion of the extruder. Further, the residence time in the extruder cannot be unconditionally specified because it depends on the thickness and width of the sheet and the winding speed, but it 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 lower, from the viewpoint of improving transparency and peelability from the cooling roll.

The time of 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. 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 crystallinity. The total time of contact with the heating roll is preferably 5 seconds or longer, more preferably 10 seconds or longer, and even more preferably 15 seconds or longer. The surface temperature of the cooling roll and the heating roll means the actually measured temperature of the roll surface, and can be measured using a contact thermometer.

Thus, the polylactic acid resin composition laminated 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, and more preferably 700 μm or less.

Further, each layer in the laminated sheet contains, for example, a plurality of layers P, and the thickness of one of the thickest layers is preferably 5% or more, more preferably 5% or more, based on the thickness of the entire laminated sheet from the viewpoint of impact resistance. It is 7% or more, more preferably 11% or more, still more preferably 15% or more, and from the viewpoint of transparency, it is preferably 40% or less, more preferably 35% or less, still more preferably 28% or less, still more preferably 25. % Or less is preferable.

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, more preferably 55/45 to 30/70.

When a plurality of layers P are contained and the thickness of one of the thickest layers 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 from the viewpoint of impact resistance. From 6% by mass or more, 8% by mass or more is more preferable, 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.

The haze value of the polylactic acid resin composition laminated sheet of the present invention is preferably 10% or less, more preferably 8% or less, still more preferably 6% or less. In the present specification, the haze value is obtained by preparing a sample of 5 cm × 5 cm × 0.3 mm from the molded sheet and measuring the integrating sphere type light transmittance specified by JIS-K7105 (HM-150 Murakami Color Technology Laboratory). Measure using.

Since the polylactic acid resin composition laminated sheet of the present invention has good transparency and excellent storage stability, it can be used as a packaging material for various applications such as daily necessities, cosmetics, and home appliances, such as blister packs, trays, and closures. It can be suitably used as a material for food containers such as lunch lids and industrial trays used for transporting and protecting industrial parts.

The present invention also provides a method for producing the polylactic acid resin composition laminated sheet of the present invention.

The production method may be any method including a step 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 method is preferably used.

Specifically, a manufacturing method having the following steps (1) to (3) can be mentioned.
Step (1): Polylactic acid resin constituting layer P by melt-kneading a raw material containing (PA) polylactic acid resin, (P-B) thermoplastic, and (PC) organic crystal nucleating agent. Steps for preparing the composition Step (2): Polylactic acid resin composition containing (QA) polylactic acid resin and (QC) organic crystal nucleating agent is melt-kneaded to form layer Q. The content of the (QC) organic crystal nucleating agent in the layer is more than 0.3% by mass and 1.0% by mass or less in the step of preparing.
Here, when the layer Q further contains the (Q-B) plasticizer, the content of the (P-B) plasticizer in the layer P is higher than that of the (Q-B) plasticizer in the layer Q. Steps greater than the content Step (3): The layer P is a sheet of the layer P polylactic acid resin composition obtained in the step (1) and the layer Q polylactic acid resin composition obtained in the step (2). A step of melt coextrusion molding so as to be the outermost layer of at least one of the front surface side and the back surface side of the

Step (1) comprises (PA) polylactic acid resin, (P-B) plasticizer, (PC) organic crystal nucleating agent, and optionally (PD) hydrolysis inhibitor. The raw material containing other additives is preferably 170 ° C. or higher, preferably 220 ° C. or lower, using a known kneader such as a closed kneader, a single-screw or twin-screw extruder, or an open roll type kneader. , More preferably, melt-kneading at a temperature of 200 ° C. or lower to prepare a polylactic acid resin composition in layer P. The conditions of the raw material and the melt-kneading conform to the section of the polylactic acid resin composition laminated sheet of the present invention.

In step (2), a raw material containing (QA) polylactic acid resin and (QC) organic crystal nucleating agent is used in a closed kneader, a single-screw or twin-screw extruder, an open roll kneader, or the like. A polylactic acid resin composition in layer Q is prepared by melt-kneading at a temperature of preferably 170 ° C. or higher, preferably 220 ° C. or lower, and more preferably 200 ° C. or lower using a known kneader. The conditions of the raw material and the melt-kneading conform to the section of the polylactic acid resin composition laminated sheet of the present invention.

In the step (3), the polylactic acid resin composition obtained in the steps (1) and (2) is melt-coextruded. The melt coextrusion molding can be performed using a known melt coextrusion molding machine, and the conditions are appropriately set so that the layer P is at least one outermost layer on the front surface side and the back surface side of the sheet from which the layer P is obtained. can do. For example, when a melt coextrusion sheet molding machine (manufactured by Soken Co., Ltd., 300 mmT-die) equipped with a cooling roll and a heating roll is used, a laminated sheet having adjusted crystallinity can be obtained. The conditions of the extruder and the conditions for contacting the cooling roll and the heating roll thereafter are in accordance with the section of the polylactic acid resin composition laminated sheet of the present invention.

The sheet after melt coextrusion may be formed by cutting the end portion, and the cut end portion is mixed with the raw material of the polylactic acid resin composition constituting the layer P and / or the layer Q after melting. Therefore, it can be used as a polylactic acid resin composition for each layer. Among them, it is preferable to use the mixture with the raw material of the polylactic acid resin composition constituting the layer Q, and as another aspect of the method for producing the polylactic acid resin composition laminated sheet of the present invention, the following step (4) is further performed. ) Can be mentioned.
Step (4): A step of cutting a part of the melt coextruded product obtained in the step (3), recovering it, and mixing it with the raw material of the polylactic acid resin composition in the step (2).

In step (4), the end portion can be cut according to a known technique. From the viewpoint of productivity, the ratio of cutting the end portion is preferably 50% by mass or less, more preferably 40% by mass or less, and further preferably 30% by mass or less of the polylactic acid resin composition laminated sheet.

Hereinafter, the present invention will be specifically described with reference to Examples. It should be noted that this embodiment is merely an example of the present invention and does not mean any limitation. The part in the example is a mass part unless otherwise specified. The "normal pressure" indicates 101.3 kPa, and the "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 3L flask equipped with a stirrer, a thermometer, and a dehydration tube, 500 g of succinic anhydride, 2463 g of triethylene glycol monomethyl ether (manufactured by Wako Pure Chemical Industries, Ltd., reagent), and paratoluenesulfonic acid monohydroxide (manufactured by Wako Pure Chemical Industries, Ltd., 9.5 g of the reagent) was charged, and the reaction was carried out at 110 ° C. for 15 hours under reduced pressure (4-10.7 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 the adsorbent Kyoward 500SH (manufactured by Kyowa Chemical Industry Co., Ltd.) to the reaction solution, stirring at 80 ° C. and 2.7 kPa for 45 minutes and filtering, the solution temperature is 115-200 ° C. and the pressure is 0.03 kPa. The glycol monomethyl ether was distilled off, and after cooling to 80 ° C., the residual liquid was filtered under reduced pressure _{to obtain a diester of succinic acid and triethylene glycol monomethyl ether [(MeEO 3} ) ₂ SA] 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 of APHA200. The present plasticizer is an ester compound with an alcohol to which 3 mol of ethylene oxide is added per hydroxyl group.

Production Example 2 of Plasticizer ((MeEO ₄ ) ₂ SA, Diester compound of succinic acid and tetraethylene glycol monomethyl ether)
Succinic anhydride (500 g), tetraethylene glycol monomethyl ether (3124 g), and p-toluenesulfonic acid monohydroxide (9.5 g) were charged in a 3 L flask equipped with a stirrer, a thermometer, and a dehydration tube, and nitrogen (500 mL / min) was added to the space. While blowing, the reaction was carried out under reduced pressure (4-10.7 kPa) at 130 ° C. for 20 hours. The acid value of the reaction solution was 1.6 mgKOH / g. After adding 27 g of the adsorbent Kyoward 500SH to the reaction solution and stirring at 80 ° C. and 2.7 kPa for 45 minutes for filtration, the 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 of succinic acid and tetraethylene glycol monomethyl ether [(MeEO 4} ) ₂ SA] 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. The present plasticizer is an ester compound with an alcohol to which 4 mol of ethylene oxide is added per hydroxyl group.

Production Example 3 of Plasticizer ((MeEO ₆ ) ₂ SA, Diester compound of succinic acid and hexaethylene glycol monomethyl ether)
Succinic anhydride (500 g), hexaethylene glycol monomethyl ether (4235 g), and p-toluenesulfonic acid monohydroxide (9.5 g) were charged in a 3 L flask equipped with a stirrer, a thermometer, and a dehydration tube, and nitrogen (500 mL / min) was added to the space. While blowing, the reaction was carried out under reduced pressure (4-10.7 kPa) at 150 ° C. for 40 hours. The acid value of the reaction solution was 1.6 mgKOH / g. 27 g of the adsorbent Kyoward 500SH was added to the reaction solution, and the mixture was stirred and filtered at 80 ° C. and 2.7 kPa for 45 minutes, and then 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 residual liquid was filtered under reduced pressure _{to obtain a diester of succinic acid and hexaethylene glycol monomethyl ether [(MeEO 6} ) ₂ SA] 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. The present plasticizer is an ester compound with an alcohol to which 6 mol of ethylene oxide is added per hydroxyl group.

Production Example 4 of Plasticizer (MeSA-1,3PD, oligoester compound of dimethyl succinate and 1,3-propanediol)
86.8 g (1.14 mol) of 1,3-propanediol in a 4-tubular flask (with stirrer, thermometer, dropping funnel, distillation tube, nitrogen blowing tube) and 2.2 g of methanol solution containing 28 wt% sodium methoxide as a catalyst. (0.011 mol of sodium methoxide) was added, and methanol was distilled off while stirring at 120 ° C. at normal pressure for 0.5 hours. Then, 500 g (3.42 mol) of dimethyl succinate (manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise over 2 hours, and methanol produced by the reaction was distilled off at 120 ° C. at normal pressure. Next, the temperature was cooled to 75 ° C., the pressure was gradually lowered from normal pressure to 6.7 kPa over 2 hours to distill off methanol, and then the pressure was returned to normal pressure, and 28 wt% sodium methoxide-containing methanol was used as a catalyst. 2.0 g of the solution (0.010 mol of sodium methoxide) was added, and the pressure was gradually lowered from normal pressure to 2.9 kPa over 3 hours at 100 ° C. to distill out methanol. Then, the mixture was cooled to 80 ° C., 6 g of Kyoward 600S (manufactured by Kyowa Chemical Industry Co., Ltd.) was added, 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 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 residual dimethyl succinate to obtain [MeSA-1,3PD] as a room temperature yellow liquid. The amount of the catalyst used was 0.61 mol with respect to 100 mol of the dicarboxylic acid ester. The plasticizer is an ester compound represented by the formula (I) (R1 is a methyl group, R2 is an ethylene group, R3 is a propylene group, m is 1 and n is 1.5).

Examples 1 to 7 and Comparative Examples 1 to 2
Preparation of Polylactic Acid Resin Composition As a polylactic acid resin composition, the composition raw materials shown in Table 1 are used in a twin-screw extruder (Perker, HK25D, cylinder diameter 25.2 mm, rotation speed 100 rpm, discharge rate 8 kg / h). Was melt-kneaded at a melt-kneading temperature of 180 to 190 ° C., and strand cut was performed to obtain pellets of a polylactic acid resin composition. The obtained pellets were dried under reduced pressure at 110 ° C. for 2 hours to bring the water content to 500 ppm or less.

Preparation of Laminated Sheet by Coextrusion Molding The pellets of layer P obtained above and the pellets used as the raw material of layer Q are used in a multi-manifold T-die extruder of 2 types and 3 layers (manufactured by Plastic Engineering Laboratory, 300 mmT). A coextruded sheet having a width of 250 mm was formed using a die) under the conditions shown in Table 2 to obtain a polylactic acid resin composition laminated sheet having a sheet thickness of 300 μm.

The raw materials in Table 1 are as follows.
<Polylactic acid resin>
4032D: NatureWorks LLC Ingeo® Biopolymer 4032D (poly-L-lactic acid, optical purity 98.5%, melting point 166 ° C., weight average molecular weight 180,000)
<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: The diester compound produced in Production Example 1 of the plasticizer.
(MeEO ₄ ) ₂ SA: The diester compound produced in Production Example 2 of the plasticizer.
(MeEO ₆ ) ₂ SA: Diester compound produced in Production Example 3 of the plasticizer MeSA-1, 3PD: Oligoester compound produced in Production Example 4 of the plasticizer <organic crystal nucleating agent>
Slipax H: Ethylenebis 12-hydroxystearic acid amide, manufactured by Nippon Kasei Co., Ltd. <Hydrolysis inhibitor>
BioAdmide 100: Diisopropylphenylcarbodiimide, manufactured by Rheinchemy

The characteristics of the obtained laminated sheet were evaluated according to the methods of Test Examples 1 to 3 below. The layer ratio was measured as follows. The results are shown in Table 1.
<Layer ratio>
The resin used for the inner layer is colored with a black pigment (carbon black), and the fracture surface of the obtained laminated sheet is prepared using a microtome, and at 200 times using an optical microscope (Keyence, VHX-1000). After observing, the sheet thickness and the thickness of the colored layer of the inner 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 Technology Laboratory) specified by JIS-K7105. The smaller the value, the better the transparency. The results are shown in Table 1.

Test Example 2
<Storage test>
A sample of 5 cm x 5 cm x 0.3 mm was prepared from the molded sheet and stored for 7 days at a temperature of 60 ° C. and a humidity of 30% using a constant temperature and humidity controller (PL-3J, manufactured by ESPEC), and then Test Example 1 The haze value was measured in the same manner as above. The results are shown in Table 1.

<Storage stability>
The difference in haze value before and after storage was calculated. If this difference is 1.5% or less, it means that the storage stability is good. The results are shown in Table 1.

<Impact resistance>
A sample of 5 cm x 5 cm x 0.3 mm was prepared from the molded sheet, and a DuPont type drop impact tester (manufactured by Yasuda Seiki Seisakusho, No. 517-L, drop height maximum 1000 mm, interval 50 mm, diameter 19.05 mm). Using a shooting type, a cradle with a diameter of 19.05 mm, and a drop weight of 100 to 1000 g), the impact strength was 50% impact destruction energy measured in an atmosphere at a temperature of 23 ° C. in accordance with JIS-K7211-1 (2006). .. The larger the value of impact strength, the better the impact resistance. The results are shown in Table 1.

From Table 1, it can be seen that the polylactic acid resin composition laminated sheet of each example containing the organic crystal nucleating agent in the layer Q is excellent in transparency, storage stability, and impact resistance. On the other hand, in Comparative Example 1 containing no organic crystal nucleating agent and Comparative Example 2 in a small amount, the transparency immediately after preparation is excellent, but the storage stability is inferior to that of the polylactic acid resin composition laminated sheet of the present invention. Met.

Since the polylactic acid resin composition laminated sheet of the present invention is excellent in transparency and storage stability, it is suitably used for various applications such as food containers, packaging materials for daily necessities and home appliances, trays for industrial parts, and the like. Can be done.

Claims (6)

A polylactic acid resin composition laminated sheet containing a plurality of layers of a polylactic acid resin composition, and a polylactic acid resin composition laminated sheet containing at least the next layers P and Q.
Layer P is, (P-A) polylactic acid resin, (P-B) a plasticizer, and (P-C) is a layer of polylactic acid resin composition containing the organic crystal nucleating agent, in the layer (P- B) The plasticizer is an ester compound having two or more ester groups in the molecule, and at least one of the alcohol components constituting the ester compound averages 0 alkylene oxides having 2 to 3 carbon atoms per hydroxyl group. It is an ester compound which is an alcohol to which 5 to 8 mol is added, and the content of the (PC) organic crystal nucleating agent in the layer is 0.05% by mass or more and 1.0% by mass or less.
Layer Q is a layer of the polylactic acid resin composition containing the (QA) polylactic acid resin and the (QC) organic crystal nucleating agent, and the layer contains the (QC) organic crystal nucleating agent. The amount is more than 0.3% by mass and 0.8 % by mass or less,
Here, when the layer Q further contains the (Q-B) plasticizer, the content of the (P-B) plasticizer in the layer P is higher than that of the (Q-B) plasticizer in the layer Q. A laminated sheet of a polylactic acid resin composition having a content higher than that of the sheet, wherein at least one outermost layer on the front surface side and the back surface side is the layer P. The polylactic acid resin composition laminated sheet according to claim 1, wherein the content of the (P-B) plasticizer in the layer P is 4% by mass or more and 18% by mass or less. The polylactic acid resin composition according to claim 1 or 2 , which comprises a plurality of layers P, and the thickness of one of the thickest layers P is 5% or more and 40% or less with respect to the thickness of the polylactic acid resin composition laminated sheet. Material laminated sheet. The polylactic acid resin composition laminated sheet according to any one of claims 1 to 3 , further comprising a plurality of layers P, wherein the layer Q is laminated between at least two layers P. ( QB) The plasticizer is
(I) An ester compound having two or more ester groups in the molecule, and at least one of the alcohol components constituting the ester compound contains an average of 0.5 alkylene oxide having 2 to 3 carbon atoms per hydroxyl group. Ester compounds that are alcohols with ~ 8 mol added, and formula (I):
R ¹ O-CO-R ² -CO-[(OR ³ ) _m O-CO-R ^2- CO-] _n OR ¹ (I)
(In the formula, 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 , N indicates a number from 1 to 12, but all R ^2s may be the same or different, and all R ^3s may be the same or different).
The polylactic acid resin composition laminated sheet according to any one of claims 1 to 4 , which comprises one kind or two or more kinds selected from the group consisting of the compounds represented by. A method for producing a polylactic acid resin composition laminated sheet containing a plurality of layers of a polylactic acid resin composition, which comprises the following steps (1), (2), and (3) to produce a polylactic acid resin composition laminated sheet. Method.
Step (1): Polylactic acid resin constituting layer P by melt-kneading a raw material containing (PA) polylactic acid resin, (P-B) plasticizer, and (PC) organic crystal nucleating agent. In the step of preparing the composition, the (P-B) plastic agent in the layer is an ester compound having two or more ester groups in the molecule, and at least one of the alcohol components constituting the ester compound. Is an ester compound in which an average of 0.5 to 8 mol of alkylene oxide having 2 to 3 carbon atoms per hydroxyl group is added, and the content of the (PC) organic crystal nucleating agent in the layer is 0.05. Steps of mass% or more and 1.0 mass% or less Step (2): A raw material containing (QA) polylactic acid resin and (QC) organic crystal nucleating agent is melt-kneaded and kneaded. In the step of preparing the polylactic acid resin composition constituting the layer Q, the content of the (QC) organic crystal nucleating agent in the layer is more than 0.3% by mass and 0.8 % by mass or less. ,
Here, when the layer Q further contains the (Q-B) plasticizer, the content of the (P-B) plasticizer in the layer P is higher than that of the (Q-B) plasticizer in the layer Q. Steps greater than the content Step (3): The layer P is a sheet of the layer P polylactic acid resin composition obtained in the step (1) and the layer Q polylactic acid resin composition obtained in the step (2). A step of melt coextrusion molding so as to be the outermost layer of at least one of the front surface side and the back surface side of the