JP2007126539A - Method for producing expandable polylactic acid-based resin - Google Patents
Method for producing expandable polylactic acid-based resin Download PDFInfo
- Publication number
- JP2007126539A JP2007126539A JP2005319824A JP2005319824A JP2007126539A JP 2007126539 A JP2007126539 A JP 2007126539A JP 2005319824 A JP2005319824 A JP 2005319824A JP 2005319824 A JP2005319824 A JP 2005319824A JP 2007126539 A JP2007126539 A JP 2007126539A
- Authority
- JP
- Japan
- Prior art keywords
- polylactic acid
- acid resin
- elastic modulus
- resin
- based resin
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Abstract
Description
本発明は、発泡性ポリ乳酸系樹脂の製造方法に関する。 The present invention relates to a method for producing a foamable polylactic acid resin.
ポリ乳酸系樹脂は、天然に存在する乳酸を重合されて得られた樹脂であり、自然界に存在する微生物によって分解可能な生分解性樹脂であると共に、常温での機械的特性についても優れていることから注目を集めている。 Polylactic acid resin is a resin obtained by polymerizing naturally occurring lactic acid, is a biodegradable resin that can be decomposed by microorganisms existing in nature, and has excellent mechanical properties at room temperature. It attracts attention.
ポリ乳酸系樹脂の原料となる乳酸は、分子中に不斉炭素原子を有するために光学活性を示し、Ｄ体、Ｌ体、及び、Ｄ体とＬ体とが等量混合してなるラセミ体の三種類が存在する。 Lactic acid, which is a raw material for polylactic acid-based resins, exhibits optical activity because it has an asymmetric carbon atom in the molecule, and racemates in which D-form, L-form, and D-form and L-form are mixed in equal amounts There are three types.
そのために、乳酸を重合させて得られるポリ乳酸系樹脂は、上記三種類の乳酸の混合割合と重合方法を調整することによって種々の性質を有するものとすることができ、現実に、ポリ乳酸系樹脂には、結晶性のものから非結晶性のものまで多種多様存在し、融点又は軟化点も様々である。 Therefore, the polylactic acid resin obtained by polymerizing lactic acid can have various properties by adjusting the mixing ratio of the above three kinds of lactic acid and the polymerization method. There are a wide variety of resins ranging from crystalline to non-crystalline, and the melting point or softening point varies.
このようなポリ乳酸系樹脂を用いたポリ乳酸発泡性粒子の製造方法として、特許文献１には、ポリ乳酸を主成分とし、示差走査熱量測定における発熱量が１５Ｊ／ｇ以上の樹脂粒子に、二酸化炭素を所定条件を満たす雰囲気温度にて含浸させる方法が提案されている。 As a method for producing polylactic acid foamable particles using such a polylactic acid-based resin, Patent Literature 1 discloses that polylactic acid is a main component and the calorific value in differential scanning calorimetry is 15 J / g or more. A method of impregnating carbon dioxide at an ambient temperature that satisfies a predetermined condition has been proposed.
しかしながら、上述の製造方法で製造されたポリ乳酸発泡性粒子を用いて得られたポリ乳酸系樹脂発泡成形品は、その平均気泡径が大きく加熱寸法変化率も大きいといった問題点があった。 However, the polylactic acid resin foam molded article obtained by using the polylactic acid foamable particles produced by the above-described production method has a problem that the average cell diameter is large and the heating dimensional change rate is large.
本発明は、平均気泡径が小さくて加熱寸法安定性に優れたポリ乳酸系樹脂発泡成形品を得ることができる発泡性ポリ乳酸系樹脂の製造方法を提案する。 The present invention proposes a method for producing a foamable polylactic acid-based resin capable of obtaining a polylactic acid-based resin foam-molded article having a small average cell diameter and excellent heat dimensional stability.
本発明の発泡性ポリ乳酸系樹脂の製造方法は、動的粘弾性測定にて得られた、貯蔵弾性率曲線と損失弾性率曲線との交点Ａにおける温度Ｔが１２０〜１５０℃であり且つ上記交点Ａにおける貯蔵弾性率が１．０×１０3 〜１．０×１０5 Ｐａであるポリ乳酸系樹脂に無機ガスを１．４〜 ３．５ＭＰａの圧力で気相含浸させることを特徴とする。 In the method for producing a foamable polylactic acid resin of the present invention, the temperature T at the intersection A between the storage elastic modulus curve and the loss elastic modulus curve obtained by dynamic viscoelasticity measurement is 120 to 150 ° C. and A polylactic acid resin having a storage elastic modulus at an intersection A of 1.0 × 10 3 to 1.0 × 10 5 Pa is impregnated with an inorganic gas at a pressure of 1.4 to 3.5 MPa. .
上記ポリ乳酸系樹脂は下記式１で示される。このポリ乳酸系樹脂は、Ｌ−乳酸及び／又はＤ−乳酸を重合させるか、或いは、Ｌ−ラクチド、Ｄ−ラクチド及びＤＬ−ラクチドからなる群より選ばれた一又は二以上のラクチドを開環重合させることによって得ることができ、何れのポリ乳酸系樹脂であってもよい。 The polylactic acid-based resin is represented by the following formula 1. This polylactic acid resin polymerizes L-lactic acid and / or D-lactic acid, or opens one or two or more lactides selected from the group consisting of L-lactide, D-lactide and DL-lactide. Any polylactic acid resin can be used.
ポリ乳酸系樹脂を製造するに際して、モノマーとしてＬ体又はＤ体のみ、或いは、モノマーとしてＬ体とＤ体とを併用した場合においてＬ体又はＤ体の何れか一方を他方に比して多量に用いた時は、得られるポリ乳酸系樹脂は結晶性となる一方、モノマーとしてＬ体とＤ体とを略同量づつ用いた場合には、得られるポリ乳酸系樹脂は非結晶性となるが、耐熱性及び機械的強度に優れている点から、本発明においては、結晶性のポリ乳酸系樹脂が好ましい。 When producing a polylactic acid-based resin, only L-form or D-form is used as a monomer, or when L-form and D-form are used in combination as a monomer, either L-form or D-form is larger than the other. When used, the resulting polylactic acid-based resin becomes crystalline, while when the L-form and D-form are used as monomers in substantially the same amount, the resulting polylactic acid-based resin becomes amorphous. From the viewpoint of excellent heat resistance and mechanical strength, a crystalline polylactic acid resin is preferred in the present invention.
そして、ポリ乳酸系樹脂を製造する際に用いられるモノマーとしてＬ体とＤ体とを併用した場合、モノマー中におけるＤ体の含有量は、少ないと、発泡性ポリ乳酸系樹脂を用いて得られるポリ乳酸系樹脂発泡成形品が硬くて脆くなることがある一方、多いと、得られるポリ乳酸系樹脂発泡成形品が柔らかくなって機械的強度が低下することがあるので、０．５〜５重量％が好ましく、０．５〜４重量％がより好ましい。 And when L body and D body are used together as a monomer used when manufacturing a polylactic acid-type resin, when there is little content of D body in a monomer, it will be obtained using foamable polylactic acid-type resin. On the other hand, the polylactic acid-based resin foamed molded product may be hard and brittle. On the other hand, if the polylactic acid-based resin foamed molded product is large, the resulting polylactic acid-based resin foamed molded product may become soft and mechanical strength may be lowered. % Is preferable, and 0.5 to 4% by weight is more preferable.
ここで、動的粘弾性測定にて得られた貯蔵弾性率は、粘弾性において弾性的な性質を示す指標であって、発泡過程における気泡膜の弾性の大小を示す指標であり、発泡過程において、気泡膜の収縮力に抗して気泡を膨張させるのに必要な発泡圧の大小を示す指標である。 Here, the storage elastic modulus obtained by the dynamic viscoelasticity measurement is an index indicating elastic properties in the viscoelasticity, and is an index indicating the elasticity of the bubble film in the foaming process. This is an index indicating the magnitude of the foaming pressure required to expand the bubbles against the contraction force of the bubble film.
即ち、ポリ乳酸系樹脂の動的粘弾性測定にて得られた貯蔵弾性率が低いと、気泡膜が伸長された場合、気泡膜が伸長力に抗して収縮しようとする力が小さく、密度が０．０３〜０．１ｇ／ｃｍ3 のポリ乳酸系樹脂発泡成形品の製造に必要とする発泡圧によって発泡膜が容易に伸長してしまう結果、気泡膜が過度に伸長してしまい破泡を生じる一方、ポリ乳酸系樹脂の動的粘弾性測定にて得られた貯蔵弾性率が高いと、気泡膜に伸長力が加わった場合、伸長に抗する気泡膜の収縮力が大きく、密度が０．０３〜０．１ｇ／ｃｍ3 のポリ乳酸系樹脂発泡成形品の製造に必要とする発泡圧で一旦、気泡が膨張したとしても、温度低下などに起因する経時的な発泡圧の低下に伴って気泡が収縮してしまう。 That is, if the storage elastic modulus obtained by the dynamic viscoelasticity measurement of polylactic acid resin is low, when the bubble membrane is stretched, the force that the bubble membrane tends to contract against the stretching force is small, and the density As a result of the foaming film being easily stretched by the foaming pressure required for the production of a polylactic acid resin foam molded article having a weight ratio of 0.03 to 0.1 g / cm 3 , the foamed film is excessively stretched, resulting in bubble breakage. On the other hand, when the storage elastic modulus obtained by the dynamic viscoelasticity measurement of the polylactic acid resin is high, when the expansion force is applied to the bubble film, the shrinkage force of the bubble film against expansion is large, and the density is high. once in 0.03~0.1g / cm 3 of the polylactic acid-based resin foam molded article foaming pressure that requires the production of, even if air bubbles is expanded, the decrease with time in the foaming pressure due to such a temperature decrease As a result, the bubbles contract.
又、動的粘弾性測定にて得られた損失弾性率は、粘弾性において粘性的な性質を示す指標であって、発泡過程における気泡膜の粘性を示す指標であり、発泡過程において、気泡膜をどの程度まで破れることなく伸長させることができるかの許容範囲を示す指標であると同時に、発泡圧によって所望大きさに気泡を膨張させた後、この膨張した気泡をその大きさに維持する能力を示す指標でもある。 Further, the loss modulus obtained by dynamic viscoelasticity measurement is an index indicating a viscous property in viscoelasticity, and is an index indicating the viscosity of the bubble film in the foaming process. This is an index indicating the allowable range of how much can be expanded without breaking, and at the same time, the ability to expand the bubbles to the desired size by the foaming pressure and then maintain the expanded bubbles at that size It is also an indicator that indicates.
即ち、ポリ乳酸系樹脂の動的粘弾性測定にて得られた損失弾性率が低いと、密度が０．０３〜０．１ｇ／ｃｍ3 のポリ乳酸系樹脂発泡成形品の製造に必要とする発泡圧によって気泡膜が伸長された場合、気泡膜が容易に破れてしまう一方、ポリ乳酸系樹脂の動的粘弾性測定にて得られた損失弾性率が高いと、発泡力が気泡膜によって熱エネルギーに変換されてしまい、気泡膜を伸長させることができず、気泡を膨張させることができない。 That is, when the loss elastic modulus obtained by the dynamic viscoelasticity measurement of the polylactic acid-based resin is low, it is necessary for producing a polylactic acid-based resin foam molded article having a density of 0.03 to 0.1 g / cm 3 When the cell membrane is stretched by the foaming pressure, the cell membrane is easily broken. On the other hand, if the loss elastic modulus obtained by the dynamic viscoelasticity measurement of the polylactic acid resin is high, the foaming force is heated by the cell membrane. It is converted into energy, the bubble film cannot be expanded, and the bubbles cannot be expanded.
このように、ポリ乳酸系樹脂を発泡させ、密度が０．０３〜０．１ｇ／ｃｍ3 といった発泡倍率が高倍率のポリ乳酸系樹脂発泡成形品を製造するにあたっては、発泡過程において、ポリ乳酸系樹脂は、密度が０．０３〜０．１ｇ／ｃｍ3 のポリ乳酸系樹脂発泡成形品を得るために必要とされる発泡圧によって気泡膜が破れることなく適度に伸長するための弾性力、即ち、貯蔵弾性率を有している必要があると共に、上記発泡圧によって気泡膜が破れることなく円滑に伸長し、所望大きさに膨張した気泡をその大きさに発泡圧の経時的な減少にかかわらず維持しておくための粘性力、即ち、損失弾性率を有している必要がある。 As described above, when a polylactic acid resin is foamed and a polylactic acid resin foam-molded article having a high expansion ratio such as a density of 0.03 to 0.1 g / cm 3 is produced, -Based resin has an elastic force to stretch appropriately without breaking the cell membrane due to the foaming pressure required to obtain a polylactic acid resin foam molded article having a density of 0.03 to 0.1 g / cm 3 , In other words, it is necessary to have a storage elastic modulus, and the foaming pressure smoothly expands without breaking the bubble film, and bubbles expanded to a desired size are reduced to the size of the foaming pressure over time. Regardless, it is necessary to have a viscous force to maintain, that is, a loss elastic modulus.
つまり、発泡工程において、ポリ乳酸系樹脂の貯蔵弾性率及び損失弾性率の双方が発泡に適した値を有している必要があり、このような発泡に適した貯蔵弾性率及び損失弾性率を発泡工程においてポリ乳酸系樹脂に付与するために、発明者らが鋭意研究した結果、動的粘弾性測定にて得られた、貯蔵弾性率曲線と損失弾性率曲線との交点Ａにおける温度Ｔと、この交点Ａにおける貯蔵弾性率（又は損失弾性率）の値について着目し、交点Ａの温度Ｔ及び交点Ａにおける貯蔵弾性率（又は損失弾性率）の値を調整することによって、ポリ乳酸系樹脂における貯蔵弾性率及び損失弾性率のバランスをとると共に無機ガスを所定圧力で気相含浸させることによって、ポリ乳酸系樹脂の発泡性を良好なものとし、密度が０．０３〜０．１ｇ／ｃｍ3 程度の高発泡倍率なポリ乳酸系樹脂発泡成形品を安定的に製造することができる発泡性ポリ乳酸系樹脂を製造することができることを見出した。 That is, in the foaming process, both the storage elastic modulus and loss elastic modulus of the polylactic acid-based resin must have values suitable for foaming, and the storage elastic modulus and loss elastic modulus suitable for such foaming are set. The temperature T at the intersection A between the storage elastic modulus curve and the loss elastic modulus curve obtained by dynamic viscoelasticity measurement as a result of the inventors' intensive research to give to the polylactic acid resin in the foaming process Focusing on the value of the storage elastic modulus (or loss elastic modulus) at the intersection A, and adjusting the temperature T of the intersection A and the value of the storage elastic modulus (or loss elastic modulus) at the intersection A, the polylactic acid resin The storage elastic modulus and loss elastic modulus of the polylactic acid resin are balanced and an inorganic gas is impregnated in a gas phase at a predetermined pressure to improve the foamability of the polylactic acid resin, and the density is 0.03 to 0.1 g / cm. 3 degree It found that it is possible to manufacturing the expandable polylactic acid resin a high expansion ratio of polylactic acid resin foamed molded article can be stably manufactured.
更に、ポリ乳酸系樹脂の動的粘弾性測定にて得られた、貯蔵弾性率曲線と損失弾性率曲線との交点Ａにおける温度Ｔと、この交点Ａにおける貯蔵弾性率（又は損失弾性率）を調整した理由を下記に詳述する。 Furthermore, the temperature T at the intersection A between the storage elastic modulus curve and the loss elastic modulus curve obtained by the dynamic viscoelasticity measurement of the polylactic acid resin, and the storage elastic modulus (or loss elastic modulus) at the intersection A are The reason for the adjustment will be described in detail below.
先ず、ポリ乳酸系樹脂の動的粘弾性測定にて得られた、貯蔵弾性率曲線と損失弾性率曲線との交点Ａにおける温度Ｔが低いと、発泡性ポリ乳酸系樹脂を用いて得られるポリ乳酸系樹脂発泡成形品に収縮が生じる一方、高いと、発泡性ポリ乳酸系樹脂の発泡性が低下して気泡が形成されにくくなるので、１２０〜１５０℃に限定され、１２５〜１４０℃が好ましい。 First, when the temperature T at the intersection A between the storage elastic modulus curve and the loss elastic modulus curve obtained by the dynamic viscoelasticity measurement of the polylactic acid resin is low, the polyacrylic resin obtained using the foamable polylactic acid resin is used. On the other hand, shrinkage occurs in the lactic acid resin foamed molded product, while if it is high, the foamability of the foamable polylactic acid resin is lowered and it is difficult to form bubbles, so the temperature is limited to 120 to 150 ° C, and 125 to 140 ° C is preferable. .
なお、ポリ乳酸系樹脂の動的粘弾性測定にて得られた、貯蔵弾性率曲線と損失弾性率曲線との交点Ａにおける温度Ｔを調整する方法としては、ポリ乳酸系樹脂の重量平均分子量が高くなるにしたがって、ポリ乳酸系樹脂の動的粘弾性測定にて得られた、貯蔵弾性率曲線と損失弾性率曲線との交点Ａにおける温度Ｔが高くなることから、ポリ乳酸系樹脂の重合時に反応時間或いは反応温度を調整することによって得られるポリ乳酸系樹脂の重量平均分子量を調整する方法、押出発泡前に或いは押出発泡時にポリ乳酸系樹脂の重量平均分子量を増粘剤や架橋剤を用いて調整する方法が挙げられる。 In addition, as a method of adjusting the temperature T at the intersection A of the storage elastic modulus curve and the loss elastic modulus curve obtained by the dynamic viscoelasticity measurement of the polylactic acid resin, the weight average molecular weight of the polylactic acid resin is As the temperature T increases, the temperature T at the intersection A between the storage elastic modulus curve and the loss elastic modulus curve obtained by the dynamic viscoelasticity measurement of the polylactic acid resin increases. A method of adjusting the weight average molecular weight of the polylactic acid resin obtained by adjusting the reaction time or reaction temperature, the viscosity average molecular weight of the polylactic acid resin before or during extrusion foaming using a thickener or a crosslinking agent Adjustment method.
このような観点から、ポリ乳酸系樹脂の重量平均分子量は、１４００００〜３０００００が好ましく、１５００００〜２７００００がより好ましく、１６００００〜２５００００が特に好ましい。更に、ポリ乳酸系樹脂の分子量分布（重量平均分子量Ｍｗ／数平均分子量Ｍｎ）は、３．２〜１０が好ましく、３．４〜９がより好ましく、３．６〜８が特に好ましい。 From such a viewpoint, the weight average molecular weight of the polylactic acid-based resin is preferably 140000 to 300000, more preferably 150,000 to 270000, and particularly preferably 160000 to 250,000. Furthermore, the molecular weight distribution (weight average molecular weight Mw / number average molecular weight Mn) of the polylactic acid-based resin is preferably 3.2 to 10, more preferably 3.4 to 9, and particularly preferably 3.6 to 8.
ここで、ポリ乳酸系樹脂の動的粘弾性測定にて得られた、貯蔵弾性率曲線と損失弾性率曲線との交点Ａにおける温度Ｔは下記の要領で測定されたものをいう。即ち、ポリ乳酸系樹脂を９．３３×１０4 Ｐａの減圧下にて８０℃で３時間に亘って乾燥する。このポリ乳酸系樹脂を該ポリ乳酸系樹脂の融点よりも４０〜５０℃だけ高い温度に加熱した測定プレート上に載置して窒素雰囲気下にて５分間に亘って放置し溶融させる。 Here, the temperature T at the intersection A between the storage elastic modulus curve and the loss elastic modulus curve obtained by the dynamic viscoelasticity measurement of the polylactic acid-based resin means that measured in the following manner. That is, the polylactic acid resin is dried at 80 ° C. for 3 hours under a reduced pressure of 9.33 × 10 4 Pa. This polylactic acid-based resin is placed on a measurement plate heated to a temperature higher by 40 to 50 ° C. than the melting point of the polylactic acid-based resin, and allowed to stand for 5 minutes in a nitrogen atmosphere to melt.
次に、直径が２５ｍｍの平面円形状の押圧板を用意し、この押圧板を用いて測定プレート上のポリ乳酸系樹脂を押圧板と測定プレートとの対向面間の間隔が１ｍｍとなるまで上下方向に押圧する。そして、押圧板の外周縁からはみ出したポリ乳酸系樹脂を除去した後、５分間に亘って放置する。 Next, a flat circular pressure plate having a diameter of 25 mm is prepared, and the polylactic acid resin on the measurement plate is moved up and down until the distance between the opposing surfaces of the pressure plate and the measurement plate becomes 1 mm. Press in the direction. And after removing the polylactic acid-type resin which protruded from the outer periphery of a press plate, it is left to stand for 5 minutes.
しかる後、歪み５％、周波数１ｒａｄ／秒、降温速度２℃／分、測定間隔３０秒の条件下にて、ポリ乳酸系樹脂の動的粘弾性測定を行って貯蔵弾性率及び損失弾性率を測定する。次に、横軸を温度とし、縦軸を貯蔵弾性率及び損失弾性率として、貯蔵弾性率曲線及び損失弾性率曲線を描く。なお、貯蔵弾性率曲線及び損失弾性率曲線を描くにあたっては、測定温度を基準として互いに隣接する測定値同士を直線で結ぶ。 Thereafter, the dynamic viscoelasticity measurement of the polylactic acid resin is performed under the conditions of 5% strain, frequency 1 rad / sec, temperature drop rate 2 ° C./min, and measurement interval 30 sec to determine the storage elastic modulus and loss elastic modulus. taking measurement. Next, a storage elastic modulus curve and a loss elastic modulus curve are drawn with the horizontal axis as temperature and the vertical axis as storage elastic modulus and loss elastic modulus. In drawing the storage elastic modulus curve and the loss elastic modulus curve, the measurement values adjacent to each other are connected with a straight line based on the measurement temperature.
そして、得られた貯蔵弾性率曲線と損失弾性率曲線との交点における温度Ｔを上記グラフから読み取ることによって得ることができる。なお、貯蔵弾性率曲線と損失弾性率曲線とが複数箇所において互いに交差する場合は、貯蔵弾性率曲線と損失弾性率曲線との複数の交点における温度のうち最も高い温度を、貯蔵弾性率曲線と損失弾性率曲線との交点における温度Ｔとする。 And it can obtain by reading the temperature T in the intersection of the obtained storage elastic modulus curve and loss elastic modulus curve from the said graph. When the storage modulus curve and the loss modulus curve intersect each other at a plurality of locations, the highest temperature among the temperatures at the plurality of intersections of the storage modulus curve and the loss modulus curve is defined as the storage modulus curve. It is set as the temperature T in the intersection with a loss elastic modulus curve.
なお、動的粘弾性測定にて得られた、貯蔵弾性率曲線と損失弾性率曲線との交点Ａにおける温度Ｔ及びこの交点Ａにおける貯蔵弾性率（損失弾性率）は、Reologica Instruments A.B 社から商品名「STRESS RHEOMETER DAR-100」にて市販されている動的粘弾性測定装置を用いて測定することができる。 The temperature T at the intersection A between the storage elastic modulus curve and the loss elastic modulus curve obtained by dynamic viscoelasticity measurement and the storage elastic modulus (loss elastic modulus) at this intersection A are products from Reologica Instruments AB. It can be measured using a dynamic viscoelasticity measuring device commercially available under the name “STRESS RHEOMETER DAR-100”.
そして、貯蔵弾性率曲線と損失弾性率曲線との交点Ａにおける貯蔵弾性率（又は損失弾性率）は、低いと、発泡中のポリ乳酸系樹脂の粘弾性が低くなり、気泡膜が発泡圧によって破れて破泡を生じて、得られたポリ乳酸系樹脂発泡成形品に収縮が発生する一方、高いと、発泡性ポリ乳酸系樹脂を発泡させて生じる気泡膜が発泡圧よりも強くなって、発泡性ポリ乳酸系樹脂を良好に発泡させることができなくなるので、１．０×１０3 〜１．０×１０5 Ｐａに限定され、５．０×１０3 〜９．０×１０4 Ｐａが好ましく、１．０×１０4 〜８．０×１０4 Ｐａがより好ましい。 When the storage elastic modulus (or loss elastic modulus) at the intersection A between the storage elastic modulus curve and the loss elastic modulus curve is low, the viscoelasticity of the polylactic acid resin being foamed becomes low, and the cell membrane is caused by the foaming pressure. While tearing and causing foam breakage, shrinkage occurs in the resulting polylactic acid resin foamed molded product, while when high, the foam film produced by foaming the foamable polylactic acid resin is stronger than the foaming pressure, Since the foamable polylactic acid resin cannot be foamed satisfactorily, it is limited to 1.0 × 10 3 to 1.0 × 10 5 Pa, and 5.0 × 10 3 to 9.0 × 10 4 Pa. Preferably, 1.0 × 10 4 to 8.0 × 10 4 Pa is more preferable.
なお、ポリ乳酸系樹脂に後述する添加剤が配合されている場合には、ポリ乳酸系樹脂の貯蔵弾性率及び損失弾性率は、添加剤が含有された状態のポリ乳酸系樹脂の貯蔵弾性率及び損失弾性率をいう。 In addition, when the additive mentioned later is mix | blended with polylactic acid-type resin, the storage elastic modulus and loss elastic modulus of polylactic acid-type resin are the storage elastic modulus of polylactic acid-type resin in the state in which the additive was contained. And loss modulus.
そして、ポリ乳酸系樹脂の動的粘弾性測定にて得られた、貯蔵弾性率曲線と損失弾性率曲線との交点における温度Ｔでの弾性率（貯蔵弾性率又は損失弾性率）は、ポリ乳酸系樹脂の重合時に反応時間或いは反応温度を調整することによって、ポリ乳酸系樹脂の重量平均分子量を調整する方法、押出発泡前に或いは押出発泡時にポリ乳酸系樹脂の重量平均分子量を増粘剤や架橋剤を用いて調整する方法が挙げられる。 The elastic modulus (storage elastic modulus or loss elastic modulus) at the temperature T at the intersection of the storage elastic modulus curve and the loss elastic modulus curve obtained by dynamic viscoelasticity measurement of the polylactic acid resin is polylactic acid A method of adjusting the weight average molecular weight of the polylactic acid resin by adjusting the reaction time or reaction temperature during polymerization of the resin, the viscosity average molecular weight of the polylactic acid resin before or during extrusion foaming The method of adjusting using a crosslinking agent is mentioned.
そして、上述のポリ乳酸系樹脂に無機ガスを所定圧力下にて気相含浸させて発泡性ポリ乳酸系樹脂を製造するが、このような無機ガスとしては、例えば、二酸化炭素、窒素、空気などが挙げられ、ポリ乳酸系樹脂との親和性に優れていることから、二酸化炭素が好ましい。 The above polylactic acid-based resin is impregnated with an inorganic gas in a gas phase under a predetermined pressure to produce a foamable polylactic acid-based resin. Examples of such inorganic gas include carbon dioxide, nitrogen, air, and the like. Carbon dioxide is preferred because of its excellent affinity with polylactic acid resins.
ポリ乳酸系樹脂に無機ガスを気相含浸させる要領としては、オートクレーブなどの密閉容器内にポリ乳酸系樹脂を供給した上で無機ガスを圧入し、ポリ乳酸系樹脂に無機ガスを含浸させる方法が挙げられる。 As a procedure for impregnating a polylactic acid resin with an inorganic gas in a gas phase, there is a method in which the polylactic acid resin is injected into an airtight container such as an autoclave and then injected, and the polylactic acid resin is impregnated with the inorganic gas. Can be mentioned.
更に、ポリ乳酸系樹脂に無機ガスを気相含浸させる際の圧力（ゲージ圧）は、低いと、ポリ乳酸系樹脂に無機ガスを充分に含浸させることができず、発泡性ポリ乳酸系樹脂の発泡性が低下する一方、高いと、無機ガスによってポリ乳酸系樹脂が可塑化し、ポリ乳酸系樹脂同士が熱融着を生じる虞れがあるので、１．４〜３．５ＭＰａに限定され、１．９〜３．０ＭＰａが好ましい。 Furthermore, if the pressure (gauge pressure) when the polylactic acid resin is impregnated with an inorganic gas in a gas phase is low, the polylactic acid resin cannot be sufficiently impregnated with the inorganic gas, On the other hand, if the foamability is lowered, the polylactic acid resin may be plasticized by the inorganic gas and the polylactic acid resin may be heat-sealed. Therefore, the foaming property is limited to 1.4 to 3.5 MPa. .9 to 3.0 MPa is preferable.
又、ポリ乳酸系樹脂に無機ガスを気相含浸させる際の温度は、低いと、発泡性ポリ乳酸系樹脂の発泡性が低下することがある一方、高いと、結晶性のポリ乳酸系樹脂の場合にポリ乳酸系樹脂の結晶化が促進してしまい、発泡性ポリ乳酸系樹脂の発泡性が低下することがあるので、３〜６０℃が好ましく、５〜５０℃がより好ましい。 In addition, if the temperature at which the polylactic acid resin is impregnated with an inorganic gas in the gas phase is low, the foamability of the foamable polylactic acid resin may be lowered. On the other hand, if the temperature is high, the crystalline polylactic acid resin may be deteriorated. In some cases, the crystallization of the polylactic acid-based resin is promoted, and the foamability of the foamable polylactic acid-based resin may be lowered. Therefore, 3 to 60 ° C is preferable, and 5 to 50 ° C is more preferable.
更に、ポリ乳酸系樹脂に無機ガスを気相含浸させる時間は、短いと、発泡性ポリ乳酸系樹脂の発泡性が低下することがある一方、長くても、得られる発泡性ポリ乳酸系樹脂の発泡性に変化はないので、８〜３０時間が好ましく、１０〜２５時間がより好ましい。 Furthermore, if the time for impregnating the polylactic acid-based resin with an inorganic gas in the gas phase is short, the foamability of the foamable polylactic acid-based resin may decrease. Since there is no change in foamability, 8 to 30 hours are preferable, and 10 to 25 hours are more preferable.
そして、ポリ乳酸系樹脂に無機ガスを気相含浸させて得られる発泡性ポリ乳酸系樹脂中に含有される無機ガス量は、少ないと、発泡性ポリ乳酸系樹脂の発泡性が低下する虞れがある一方、多いと、ポリ乳酸系樹脂が無機ガスによって可塑化されてしまい、発泡性ポリ乳酸系樹脂同士が気相含浸中に熱融着してしまう虞れがあるので、４．５〜１３重量％が好ましく、５．０〜１２．５重量％がより好ましい。 If the amount of the inorganic gas contained in the foamable polylactic acid resin obtained by impregnating the polylactic acid resin with a vapor phase of an inorganic gas is small, the foamability of the foamable polylactic acid resin may be reduced. On the other hand, if it is large, the polylactic acid-based resin is plasticized by the inorganic gas, and the foamable polylactic acid-based resins may be heat-sealed during the gas phase impregnation, 13 weight% is preferable and 5.0-12.5 weight% is more preferable.
なお、発泡性ポリ乳酸系樹脂中における無機ガス量は下記の要領で測定されたものをいう。即ち、発泡性ポリ乳酸系樹脂を１８０℃の加熱炉に供給してガスクロマトグラフから測定対象となる無機ガスのチャートを得、予め測定しておいた、測定対象となる無機ガスの検量線に基づいて、上記チャートから発泡性ポリ乳酸系樹脂中の無機ガス量を算出することができる。 In addition, the amount of inorganic gas in the foamable polylactic acid resin refers to the amount measured in the following manner. That is, the foamable polylactic acid-based resin is supplied to a heating furnace at 180 ° C., a chart of the inorganic gas to be measured is obtained from the gas chromatograph, and based on the calibration curve of the inorganic gas to be measured that has been measured in advance. Thus, the amount of inorganic gas in the foamable polylactic acid resin can be calculated from the chart.
更に、ポリ乳酸系樹脂に無機ガスを気相含浸させる際、ポリ乳酸系樹脂同士が合着する虞れがあることから、発泡助剤や分散剤を存在させないことが好ましい。このような発泡助剤としては、例えば、ベンゼン、トルエン、キシレンなどの低分子量芳香族化合物、炭素数が１〜４の脂肪族アルコール、アセトン、メチルエチルケトン、ジエチルケトンなどの脂肪族アルコールが挙げられる。又、分散剤としては、例えば、ポリビニルアルコール、ヒドロキシエチルセルロースなどが挙げられる。 Further, when the polylactic acid-based resin is impregnated with an inorganic gas in a gas phase, it is preferable that a foaming aid or a dispersant is not present because the polylactic acid-based resins may be bonded together. Examples of such foaming aids include low molecular weight aromatic compounds such as benzene, toluene, and xylene, aliphatic alcohols having 1 to 4 carbon atoms, and aliphatic alcohols such as acetone, methyl ethyl ketone, and diethyl ketone. Examples of the dispersant include polyvinyl alcohol and hydroxyethyl cellulose.
なお、発泡性ポリ乳酸系樹脂には、その物性を損なわない範囲内において、帯電防止剤、発泡セル造核剤、難燃剤、難燃助剤、滑剤、着色剤などの添加物が添加されていてもよい。 In addition, additives such as antistatic agents, foamed cell nucleating agents, flame retardants, flame retardant aids, lubricants, and colorants are added to the foamable polylactic acid-based resin within a range that does not impair the physical properties thereof. May be.
そして、発泡性ポリ乳酸系樹脂の形態としては、特に限定されず、粒子状、シート状などの何れの形態であってもよい。発泡性ポリ乳酸系樹脂粒子を製造するには、ポリ乳酸系樹脂粒子を製造し、このポリ乳酸系樹脂粒子に無機ガスを気相含浸させればよい。 And as a form of foamable polylactic acid-type resin, it does not specifically limit, Any forms, such as a particulate form and a sheet form, may be sufficient. In order to produce expandable polylactic acid-based resin particles, polylactic acid-based resin particles may be manufactured, and the polylactic acid-based resin particles may be impregnated with an inorganic gas in a gas phase.
ポリ乳酸系樹脂粒子を製造する要領としては、ポリ乳酸系樹脂を押出機に供給し溶融混練してストランド状（棒状）に押出し、このストランドを所定長さ毎に切断して円柱状として、ポリ乳酸系樹脂粒子を製造する方法、ポリ乳酸系樹脂を混練りローラーに供給して溶融混練してポリ乳酸系樹脂シートを製造し、このポリ乳酸系樹脂シートを切断機（ペレタイザー）を用いて直方体形状に切断して、ポリ乳酸系樹脂粒子を製造する方法などが挙げられる。 The procedure for producing the polylactic acid-based resin particles is to supply the polylactic acid-based resin to an extruder, melt and knead it, and extrude it into a strand shape (bar shape). A method for producing lactic acid resin particles, a polylactic acid resin is kneaded, supplied to a roller, melt-kneaded to produce a polylactic acid resin sheet, and this polylactic acid resin sheet is cuboid using a cutting machine (pelletizer) A method of producing polylactic acid-based resin particles by cutting into a shape is exemplified.
又、発泡性ポリ乳酸系樹脂シートを製造するには、ポリ乳酸系樹脂シートを製造し、このポリ乳酸系樹脂シートに無機ガスを気相含浸させればよい。ポリ乳酸系樹脂シートを製造する要領としては、ポリ乳酸系樹脂を押出機に供給し溶融混練してＴダイからシート状に押出す方法、ポリ乳酸系樹脂を押出機にて溶融混練してサーキュラダイから円筒状に押出し、押出された直後の軟化状態にある円筒状体を押出方向に連続的に内外周面間に亘って切断して切り開いて展開する方法などが挙げられる。 In order to produce a foamable polylactic acid resin sheet, a polylactic acid resin sheet may be produced, and the polylactic acid resin sheet may be impregnated with an inorganic gas in a gas phase. The procedure for producing a polylactic acid resin sheet is to supply the polylactic acid resin to an extruder, melt knead and extrude it from a T die into a sheet, or melt and knead the polylactic acid resin in an extruder to make a circular Examples include a method of extruding from a die into a cylindrical shape, cutting a cylindrical body in a softened state immediately after being extruded, between the inner and outer peripheral surfaces, cutting it open, and developing it.
次に、上述のようにして得られた発泡性ポリ乳酸系樹脂を用いてポリ乳酸系樹脂発泡成形品を製造する要領について説明する。先ず、発泡性ポリ乳酸系樹脂を加熱して予備発泡させて予備発泡体を製造する。なお、発泡性ポリ乳酸系樹脂の加熱媒体としては、例えば、水蒸気、沸騰水、熱風などが挙げられ、水蒸気が好ましい。 Next, a procedure for producing a polylactic acid resin foam molded article using the foamable polylactic acid resin obtained as described above will be described. First, a foamable polylactic acid resin is heated to be prefoamed to produce a prefoamed body. In addition, as a heating medium of foamable polylactic acid-type resin, water vapor | steam, boiling water, a hot air etc. are mentioned, for example, Water vapor | steam is preferable.
そして、予備発泡体の嵩密度は、小さいと、得られるポリ乳酸系樹脂発泡成形品が発泡時に収縮し、ポリ乳酸系樹脂発泡成形品の機械的強度が低下することがある一方、大きいと、得られるポリ乳酸系樹脂発泡成形品の軽量性が低下することがあるので、０．０３〜０．１ｇ／ｃｍ3 が好ましく、０．０３５〜０．０８ｇ／ｃｍ3 がより好ましい。 And, if the bulk density of the pre-foamed material is small, the resulting polylactic acid resin foamed molded product may shrink during foaming, and the mechanical strength of the polylactic acid resin foamed molded product may be reduced. Since the lightness of the obtained polylactic acid-based resin foam molded article may be lowered, 0.03 to 0.1 g / cm 3 is preferable, and 0.035 to 0.08 g / cm 3 is more preferable.
なお、予備発泡体の嵩密度の測定方法は、予備発泡体の形態によって異なる。先ず、予備発泡体が粒子状である場合について説明する。予備発泡粒子の嵩密度は、ＪＩＳ Ｋ６９１１：１９９５年「熱硬化性プラスチック一般試験方法」に準拠して測定されたものをいう。具体的には、ＪＩＳ Ｋ６９１１に準拠した見掛け密度測定器を用いて測定し、下記式に基づいて予備発泡粒子の嵩密度を算出することができる。
予備発泡粒子の嵩密度（ｇ／ｃｍ3 ）
＝〔試料を入れたメスシリンダーの質量（ｇ）−メスシリンダーの質量（ｇ）〕
／メスシリンダーの容量（ｃｍ3）
Note that the method for measuring the bulk density of the preliminary foam varies depending on the form of the preliminary foam. First, the case where the preliminary foam is in the form of particles will be described. The bulk density of pre-expanded particles refers to that measured according to JIS K6911: 1995 “General Test Method for Thermosetting Plastics”. Specifically, the bulk density of the pre-expanded particles can be calculated based on the following formula by measuring using an apparent density measuring instrument based on JIS K6911.
Bulk density of pre-expanded particles (g / cm 3 )
= [Mass of measuring cylinder with sample (g) -Mass of measuring cylinder (g)]
/ Capacity of measuring cylinder (cm 3 )
次に、予備発泡体がシート状である場合について説明する。予備発泡シートの嵩密度は、ＪＩＳ Ｋ７２２２：１９９９年「発泡プラスチック及びゴム−見掛け密度の測定」に準拠して測定されたものをいう。具体的には、予備発泡シートを予備発泡させた直後から７２時間以上放置して養生した後、更に、予備発泡シートを２１〜２５℃、相対湿度４５〜５５％の雰囲気下に１６時間に亘って放置する。しかる後、予備発泡シートから５０ｃｍ3 以上の試験片を予備発泡シートの気泡構造を変形させないように切り出し、この試験片の重量Ｗ2 ｇ及び見掛け体積Ｖ2 ｃｍ3 を測定し、下記式に基づいて予備発泡シートの嵩密度を算出することができる。
予備発泡シートの嵩密度（ｇ／ｃｍ3 ）＝試験片の重量Ｗ2 ／試験片の体積Ｖ2
Next, the case where the preliminary foam is in the form of a sheet will be described. The bulk density of the pre-foamed sheet refers to that measured according to JIS K7222: 1999 “Foamed plastics and rubbers—Measurement of apparent density”. Specifically, after preliminarily foaming the prefoamed sheet for 72 hours or longer and curing, the prefoamed sheet is further placed in an atmosphere of 21 to 25 ° C. and a relative humidity of 45 to 55% for 16 hours. Leave it alone. Thereafter, a test piece of 50 cm 3 or more is cut out from the pre-foamed sheet so as not to deform the cell structure of the pre-foamed sheet, and the weight W 2 g and apparent volume V 2 cm 3 of this test piece are measured. Thus, the bulk density of the prefoamed sheet can be calculated.
Bulk density of pre-foamed sheet (g / cm 3 ) = weight W 2 of test piece / volume V 2 of test piece
更に、上記予備発泡体の平均気泡径は、小さいと、予備発泡体中の気泡数が多くなって気泡膜が薄くなり、予備発泡体を二次発泡させた際に破泡してしまい、良好なポリ乳酸系樹脂発泡成形品を得ることができないことがある一方、大きいと、予備発泡体を用いて得られるポリ乳酸系樹脂発泡成形品の機械的強度が低下することがあるので、３０〜１００μｍが好ましく、４０〜９０μｍがより好ましい。 Furthermore, if the average cell diameter of the preliminary foam is small, the number of bubbles in the preliminary foam is increased and the bubble film is thinned. On the other hand, since the mechanical strength of the polylactic acid resin foam-molded product obtained using the pre-foamed material may be reduced, the polylactic acid resin foam-molded product may not be obtained. 100 micrometers is preferable and 40-90 micrometers is more preferable.
予備発泡体の平均気泡径は、ポリ乳酸系樹脂に無機ガスを気相含浸させる際の圧力を変化させることによって調整することができ、圧力を大きくする程、予備発泡体の平均気泡径を小さくすることができる。 The average cell diameter of the preliminary foam can be adjusted by changing the pressure when the polylactic acid resin is impregnated with an inorganic gas in the gas phase. The larger the pressure, the smaller the average cell diameter of the preliminary foam. can do.
なお、予備発泡体の平均気泡径は、ＡＳＴＭ Ｄ２８４２−６９の試験方法に準拠して測定された平均弦長に基づいて算出されたものをいう。具体的には、予備発泡体を任意の方向に切断し、この切断面における中央部を走査型電子顕微鏡を用いて１７〜２０倍に拡大して撮影する。 In addition, the average bubble diameter of a preliminary | backup foam means what was computed based on the average chord length measured based on the test method of ASTM D2842-69. Specifically, the pre-foamed body is cut in an arbitrary direction, and the central part of the cut surface is enlarged and photographed 17 to 20 times using a scanning electron microscope.
次に、撮影した写真において、任意の方向を指向し且つ写真上の長さが６０ｍｍである一直線上にある気泡数から、各気泡の平均弦長（ｔ）を下記式１に基づいて算出する。
平均弦長（ｔ）＝６０／（気泡数×写真の倍率）・・・式１
Next, in the photograph taken, the average chord length (t) of each bubble is calculated based on the following equation 1 from the number of bubbles that are in an arbitrary direction and are on a straight line having a length of 60 mm on the photograph. .
Average chord length (t) = 60 / (number of bubbles × photo magnification) Formula 1
そして、下記式２に基づいて気泡径Ｄを算出し、この気泡径Ｄを平均気泡径とする。
気泡径Ｄ＝ｔ／０．６１６・・・式２
And the bubble diameter D is calculated based on following formula 2, and this bubble diameter D is made into an average bubble diameter.
Bubble diameter D = t / 0.616 Expression 2
更に、予備発泡体を構成するポリ乳酸系樹脂の結晶化度は、高いと、予備発泡体の発泡力が低下して、予備発泡体が二次発泡して得られる発泡粒子同士の熱融着が不充分となることがあるので、４５％以下が好ましく、４０％以下がより好ましい。 Furthermore, if the degree of crystallinity of the polylactic acid resin constituting the pre-foamed material is high, the foaming power of the pre-foamed material is reduced, and the pre-foamed material is thermally fused between the expanded particles obtained by secondary foaming. May be insufficient, so 45% or less is preferable and 40% or less is more preferable.
なお、予備発泡体を構成するポリ乳酸系樹脂の結晶化度の調整は、発泡性ポリ乳酸系樹脂を予備発泡させる際の温度及び時間を調整することによって行うことができ、具体的には、発泡性ポリ乳酸系樹脂の予備発泡温度及び予備発泡時間を８０〜１００℃、１〜３分に調整することによって、予備発泡体の結晶化度を予備発泡体の二次発泡に適したものに調整することができる。 In addition, adjustment of the crystallinity degree of the polylactic acid-type resin which comprises a preliminary | backup foam can be performed by adjusting the temperature and time at the time of pre-foaming foamable polylactic acid-type resin, specifically, By adjusting the pre-foaming temperature and pre-foaming time of the foamable polylactic acid resin to 80 to 100 ° C. for 1 to 3 minutes, the crystallinity of the pre-foam is suitable for secondary foaming of the pre-foam. Can be adjusted.
ここで、本発明において、ポリ乳酸系樹脂の結晶化度は、示差走査熱量計（ＤＳＣ）を用いてＪＩＳ Ｋ７１２１に記載の測定方法に準拠して１０℃／分の昇温速度にて昇温しながら測定された１ｍｇ当たりの冷結晶化熱量及び１ｍｇ当たりの融解熱量に基づいて下記式により算出することができる。 Here, in the present invention, the degree of crystallinity of the polylactic acid-based resin is increased at a rate of temperature increase of 10 ° C./min using a differential scanning calorimeter (DSC) according to the measurement method described in JIS K7121. On the basis of the measured amount of cold crystallization per 1 mg and the amount of heat of fusion per 1 mg, the following formula can be used.
次に、上記予備発泡体を成形ダイのキャビティ内に充填した上で予備発泡体を加熱して二次発泡させることにより所望形状を有するポリ乳酸系樹脂発泡成形品を得ることができる。なお、予備発泡体の加熱媒体としては、予備発泡時と同様に、例えば、水蒸気、沸騰水、熱風などが挙げられ、水蒸気が好ましい。 Next, after filling the said prefoamed body in the cavity of a shaping | molding die, the prefoamed body is heated and secondary foamed, By doing, the polylactic acid-type resin foam molded product which has a desired shape can be obtained. Examples of the heating medium for the pre-foamed body include water vapor, boiling water, hot air, etc., as in the pre-foaming, and water vapor is preferred.
ここで、予備発泡体を二次発泡させてポリ乳酸系樹脂発泡成形品を成形する途上において、ポリ乳酸系樹脂の結晶化度を高めることによって、得られるポリ乳酸系樹脂発泡成形品の耐熱性を向上させることができ、具体的には、ポリ乳酸系樹脂の結晶化度が好ましくは２５％以上、より好ましくは３０〜４５％となるように調整することが好ましい。なお、ポリ乳酸系樹脂の結晶化度を高めるには、予備発泡体の二次発泡時間を長くすればよい。 Here, in the course of forming a polylactic acid resin foam molded article by secondary foaming of the pre-foamed material, the heat resistance of the polylactic acid resin foam molded article obtained by increasing the crystallinity of the polylactic acid resin Specifically, it is preferable to adjust so that the crystallinity of the polylactic acid resin is preferably 25% or more, more preferably 30 to 45%. In addition, what is necessary is just to lengthen the secondary foaming time of a preliminary | backup foam in order to raise the crystallinity degree of polylactic acid-type resin.
そして、予備発泡体を二次発泡させるにあたって水蒸気を用いた場合、水蒸気の圧力は、低いと、予備発泡体を二次発泡させて得られる発泡粒子同士の熱融着性が低下し、ポリ乳酸系樹脂発泡成形品の機械的強度が低下する一方、高いと、ポリ乳酸系樹脂が融解してしまい、良好なポリ乳酸系樹脂発泡成形品を得ることができないことがあるので、ゲージ圧で、９．８×１０4 〜３．９×１０5 Ｐａが好ましく、１．５×１０5 〜３．４×１０5 Ｐａがより好ましい。 When water vapor is used for secondary foaming of the preliminary foam, if the water vapor pressure is low, the heat-fusibility between the foamed particles obtained by secondary foaming of the preliminary foam decreases, and polylactic acid On the other hand, the mechanical strength of the resin-based resin foam molded product is reduced, but if it is high, the polylactic acid-based resin melts, and a good polylactic acid-based resin foam molded product may not be obtained. 9.8 × 10 4 to 3.9 × 10 5 Pa is preferable, and 1.5 × 10 5 to 3.4 × 10 5 Pa is more preferable.
このようにして得られたポリ乳酸系樹脂発泡成形品は、平均気泡径が小さくて加熱寸法安定性に優れ且つ低密度なものであり、食品包装材、緩衝材、工業用部材、建材、土木資材、農業用資材などの多種多様の用途に好適に用いることができる。 The polylactic acid resin foam molded article thus obtained has a small average cell diameter, excellent heat dimensional stability and low density, and is a food packaging material, cushioning material, industrial material, building material, civil engineering. It can be suitably used for a wide variety of uses such as materials and agricultural materials.
本発明の発泡性ポリ乳酸系樹脂の製造方法は、動的粘弾性測定にて得られた、貯蔵弾性率曲線と損失弾性率曲線との交点Ａにおける温度Ｔが１２０〜１５０℃であり且つ上記交点Ａにおける貯蔵弾性率が１．０×１０3 〜１．０×１０5 Ｐａであるポリ乳酸系樹脂に無機ガスを１．４〜３．５ＭＰａの圧力で気相含浸させるものであり、この製造方法により得られる発泡性ポリ乳酸系樹脂を用いることによって、加熱寸法安定性及び機械的強度に優れ且つ低密度なポリ乳酸系樹脂発泡成形品を安定的に得ることができる。 In the method for producing a foamable polylactic acid resin of the present invention, the temperature T at the intersection A between the storage elastic modulus curve and the loss elastic modulus curve obtained by dynamic viscoelasticity measurement is 120 to 150 ° C. and A polylactic acid resin having a storage elastic modulus at an intersection A of 1.0 × 10 3 to 1.0 × 10 5 Pa is impregnated with an inorganic gas at a pressure of 1.4 to 3.5 MPa. By using a foamable polylactic acid-based resin obtained by the production method, a polylactic acid-based resin foam molded article having excellent heat dimensional stability and mechanical strength and a low density can be stably obtained.
そして、上記発泡性ポリ乳酸系樹脂の製造方法において、無機ガスが二酸化炭素である場合には、二酸化炭素がポリ乳酸との親和性に優れており、得られる発泡性ポリ乳酸系樹脂を用いて得られるポリ乳酸系樹脂発泡成形品の平均気泡径をより微細なものとすることができる。 And in the manufacturing method of the said foamable polylactic acid-type resin, when inorganic gas is a carbon dioxide, carbon dioxide is excellent in affinity with polylactic acid, and using the foamable polylactic acid-type resin obtained The average cell diameter of the obtained polylactic acid resin foamed molded product can be made finer.
更に、上記発泡性ポリ乳酸系樹脂の製造方法において、ポリ乳酸系樹脂に無機ガスを３〜６０℃にて気相含浸させる場合には、ポリ乳酸系樹脂に無機ガスを効果的に含浸させ、更に優れた発泡性を有する発泡性ポリ乳酸系樹脂を製造することができる。 Furthermore, in the method for producing the foamable polylactic acid-based resin, when the polylactic acid-based resin is impregnated with a gas phase at 3 to 60 ° C., the polylactic acid-based resin is effectively impregnated with the inorganic gas, Furthermore, a foamable polylactic acid resin having excellent foamability can be produced.
（実施例１）
結晶性ポリ乳酸系樹脂（ユニチカ社製 商品名「ＴＥＲＲＡＭＡＣ ＴＥ−６１００」、貯蔵弾性率曲線と損失弾性率曲線との交点Ａにおける温度Ｔ：１４０．３℃、交点Ａにおける貯蔵弾性率（損失弾性率）：５．３７×１０4 Ｐａ、重量平均分子量：１７１０００、分子量分布（重量平均分子量／数平均分子量）：４．０５、融点：１６７．８℃）を押出機に供給して２３０℃にて溶融混練し、ストランド状に押出した。このストランドを所定長さ毎に切断して円柱状とし、１個当たり５ｍｇの重量を有するポリ乳酸系樹脂粒子を製造した。なお、図１に、ポリ乳酸系樹脂の動的粘弾性測定にて得られた、貯蔵弾性率曲線及び損失弾性率曲線を示した。
Example 1
Crystalline polylactic acid resin (trade name “TERRAMAC TE-6100” manufactured by Unitika Ltd.), temperature T at the intersection A between the storage elastic modulus curve and the loss elastic modulus curve: 140.3 ° C., storage elastic modulus at the intersection A (loss elastic) Ratio): 5.37 × 10 4 Pa, weight average molecular weight: 171000, molecular weight distribution (weight average molecular weight / number average molecular weight): 4.05, melting point: 167.8 ° C.) are supplied to the extruder to 230 ° C. And kneaded and extruded into strands. This strand was cut into a cylindrical shape at predetermined lengths to produce polylactic acid resin particles having a weight of 5 mg per one. In addition, in FIG. 1, the storage elastic modulus curve and the loss elastic modulus curve obtained by the dynamic viscoelasticity measurement of polylactic acid-type resin were shown.
次に、上記ポリ乳酸系樹脂粒子をオートクレーブ内に供給して密封し、このオートクレーブ内に二酸化炭素を圧入した上で、オートクレーブ内を３０℃に１２時間に亘って維持し、ポリ乳酸系樹脂粒子に二酸化炭素をゲージ圧で２．０ＭＰａの圧力で気相含浸させて、発泡性ポリ乳酸系樹脂粒子を得た。 Next, the polylactic acid resin particles are supplied and sealed in an autoclave, and carbon dioxide is injected into the autoclave, and then the autoclave is maintained at 30 ° C. for 12 hours. Carbon dioxide was impregnated in a gas phase at a gauge pressure of 2.0 MPa to obtain expandable polylactic acid resin particles.
続いて、得られた発泡性ポリ乳酸系樹脂粒子を予備発泡機に供給して９０℃にて１分間に亘って加熱して予備発泡させて嵩密度が０．０５ｇ／ｃｍ3 の予備発泡粒子を得た。この予備発泡粒子を成形ダイのキャビティ内に充填した上で、予備発泡粒子を圧力０．２ＭＰａの水蒸気を用いて加熱し、予備発泡粒子を二次発泡させて得られる発泡粒子同士を熱融着一体化させて、縦４００ｍｍ×横３００ｍｍ×高さ３０ｍｍのポリ乳酸系樹脂発泡成形品を得た。 Subsequently, the obtained expandable polylactic acid-based resin particles are supplied to a pre-foaming machine, heated at 90 ° C. for 1 minute to be pre-foamed, and pre-foamed particles having a bulk density of 0.05 g / cm 3. Got. After filling the pre-expanded particles in the cavity of the molding die, the pre-expanded particles are heated using water vapor at a pressure of 0.2 MPa, and the pre-expanded particles are secondarily expanded, and the expanded particles obtained are thermally fused. A polylactic acid resin foam molded product having a length of 400 mm, a width of 300 mm, and a height of 30 mm was obtained by integration.
（実施例２）
結晶性ポリ乳酸系樹脂（ユニチカ社製 商品名「ＴＥＲＲＡＭＡＣ ＴＥ−６１００」、貯蔵弾性率曲線と損失弾性率曲線との交点Ａにおける温度Ｔ：１４０．３℃、交点Ａにおける貯蔵弾性率（損失弾性率）：５．３７×１０4 Ｐａ、重量平均分子量：１７１０００、分子量分布（重量平均分子量／数平均分子量）：４．０５、融点：１６７．８℃）を押出機に供給して２３０℃にて溶融混練し、１９０℃に保持されたＴダイから厚さ１ｍｍのポリ乳酸系樹脂シートを押出した。このポリ乳酸系樹脂シートを切断機を用いて直方体形状に切断して、１個当たり１０ｍｇの重量を有するポリ乳酸系樹脂粒子を製造した。このポリ乳酸系樹脂粒子を用いて実施例１と同様にしてポリ乳酸系樹脂発泡成形品を得た。
(Example 2)
Crystalline polylactic acid resin (trade name “TERRAMAC TE-6100” manufactured by Unitika Ltd.), temperature T at the intersection A between the storage elastic modulus curve and the loss elastic modulus curve: 140.3 ° C., storage elastic modulus at the intersection A (loss elastic) Ratio): 5.37 × 10 4 Pa, weight average molecular weight: 171000, molecular weight distribution (weight average molecular weight / number average molecular weight): 4.05, melting point: 167.8 ° C.) are supplied to the extruder to 230 ° C. Then, a polylactic acid resin sheet having a thickness of 1 mm was extruded from a T die maintained at 190 ° C. This polylactic acid resin sheet was cut into a rectangular parallelepiped shape using a cutting machine to produce polylactic acid resin particles having a weight of 10 mg per one. Using the polylactic acid resin particles, a polylactic acid resin foam molded article was obtained in the same manner as in Example 1.
（実施例３）
結晶性ポリ乳酸系樹脂（ユニチカ社製 商品名「ＴＥＲＲＡＭＡＣ ＴＥ−６１００」、貯蔵弾性率曲線と損失弾性率曲線との交点Ａにおける温度Ｔ：１４０．３℃、交点Ａにおける貯蔵弾性率（損失弾性率）：５．３７×１０4 Ｐａ、重量平均分子量：１７１０００、分子量分布（重量平均分子量／数平均分子量）：４．０５、融点：１６７．８℃）を押出機に供給して２３０℃にて溶融混練して、１９０℃に保持されたサーキュラダイから厚さ０．５ｍｍの円筒状体を押出した。そして、この円筒状体をその押出方向に連続的に内外周面間に亘って切断して切り開いて展開し、長尺状のポリ乳酸系樹脂シートを得た。この長尺状のポリ乳酸系樹脂シートから一辺が２００ｍｍの平面正方形状のポリ乳酸系樹脂シートを切り出した。
(Example 3)
Crystalline polylactic acid resin (trade name “TERRAMAC TE-6100” manufactured by Unitika Ltd.), temperature T at the intersection A between the storage elastic modulus curve and the loss elastic modulus curve: 140.3 ° C., storage elastic modulus at the intersection A (loss elastic) Ratio): 5.37 × 10 4 Pa, weight average molecular weight: 171000, molecular weight distribution (weight average molecular weight / number average molecular weight): 4.05, melting point: 167.8 ° C.) are supplied to the extruder to 230 ° C. Then, a cylindrical body having a thickness of 0.5 mm was extruded from a circular die maintained at 190 ° C. And this cylindrical body was continuously cut | disconnected between the inner and outer peripheral surfaces in the extrusion direction, it opened and developed, and the elongate polylactic acid-type resin sheet was obtained. From this long polylactic acid resin sheet, a 200-mm flat square polylactic acid resin sheet was cut out.
そして、平面正方形状のポリ乳酸系樹脂シートをオートクレーブ内に供給して密封し、このオートクレーブ内に二酸化炭素を圧入した上で、オートクレーブ内を３０℃に１２時間に亘って維持し、平面正方形状のポリ乳酸系樹脂シートに二酸化炭素をゲージ圧で２．０ＭＰａの圧力で気相含浸させて、発泡性ポリ乳酸系樹脂シートを得た。 Then, a planar square polylactic acid resin sheet is supplied and sealed in the autoclave, and carbon dioxide is injected into the autoclave, and then the interior of the autoclave is maintained at 30 ° C. for 12 hours. The polylactic acid based resin sheet was impregnated with carbon dioxide in a gas phase at a gauge pressure of 2.0 MPa to obtain a foamable polylactic acid based resin sheet.
続いて、得られた発泡性ポリ乳酸系樹脂シートを予備発泡機に供給して９０℃にて１分間に亘って加熱して予備発泡させて予備発泡シートを得た。この予備発泡シートを成形ダイのキャビティ内に充填した上で、予備発泡シートを圧力が０．２ＭＰａの水蒸気を用いて加熱し、予備発泡シートを二次発泡させて得られる発泡シート同士を熱融着一体化させて、縦４００ｍｍ×横３００ｍｍ×高さ３０ｍｍのポリ乳酸系樹脂発泡成形品を得た。 Subsequently, the obtained expandable polylactic acid resin sheet was supplied to a pre-foaming machine and heated at 90 ° C. for 1 minute to be pre-foamed to obtain a pre-foamed sheet. After filling this pre-foamed sheet into the cavity of the molding die, the pre-foamed sheet is heated with water vapor having a pressure of 0.2 MPa, and the foamed sheets obtained by secondary foaming of the pre-foamed sheet are heat-fused. A polylactic acid resin foam molded product having a length of 400 mm, a width of 300 mm, and a height of 30 mm was obtained.
（実施例４）
ポリ乳酸系樹脂粒子に二酸化炭素をゲージ圧で３．０ＭＰａの圧力にて気相含浸したこと以外は実施例１と同様にしてポリ乳酸系樹脂発泡成形品を得た。
Example 4
A polylactic acid resin foam molded article was obtained in the same manner as in Example 1 except that the polylactic acid resin particles were impregnated with carbon dioxide at a gauge pressure of 3.0 MPa.
（実施例５）
ポリ乳酸系樹脂として、ユニチカ社から商品名「ＴＥＲＲＡＭＡＣ ＨＶ−６２００」で市販されている結晶性ポリ乳酸系樹脂（貯蔵弾性率曲線と損失弾性率曲線との交点Ａにおける温度Ｔ：１３９．５℃、交点Ａにおける貯蔵弾性率（損失弾性率）：４．２７×１０4 Ｐａ、１６７．４℃、重量平均分子量：１７２０００、分子量分布（重量平均分子量／数平均分子量）：３．９０、融点：１６７．４℃）を用いたこと以外は実施例１と同様にしてポリ乳酸系樹脂発泡成形品を得た。
(Example 5)
As a polylactic acid resin, a crystalline polylactic acid resin commercially available from Unitika under the trade name “TERRAMAC HV-6200” (temperature T at the intersection A between the storage elastic modulus curve and the loss elastic modulus curve: 139.5 ° C. Storage elastic modulus (loss elastic modulus) at intersection A: 4.27 × 10 4 Pa, 167.4 ° C., weight average molecular weight: 172000, molecular weight distribution (weight average molecular weight / number average molecular weight): 3.90, melting point: A polylactic acid resin foam molded article was obtained in the same manner as in Example 1 except that 167.4 ° C.) was used.
（比較例１）
ポリ乳酸系樹脂として、ユニチカ社から商品名「ＴＥＲＲＡＭＡＣ ＴＥ−４０００」で市販されている結晶性ポリ乳酸系樹脂（貯蔵弾性率曲線と損失弾性率曲線との交点Ａにおける温度Ｔ：１０５．０℃、交点Ａにおける貯蔵弾性率（損失弾性率）：１．１７×１０5 Ｐａ、融点：１７０．３℃）を用いたこと以外は実施例１と同様にしてポリ乳酸系樹脂発泡成形品を得た。なお、発泡性ポリ乳酸系樹脂粒子の予備発泡時に収縮が発生した。
(Comparative Example 1)
As a polylactic acid resin, a crystalline polylactic acid resin commercially available from Unitika under the trade name “TERRAMAC TE-4000” (temperature T at the intersection A between the storage elastic modulus curve and the loss elastic modulus curve: 105.0 ° C. A polylactic acid resin foam molded article was obtained in the same manner as in Example 1 except that the storage elastic modulus (loss elastic modulus) at the intersection A was 1.17 × 10 5 Pa and the melting point was 170.3 ° C. It was. In addition, shrinkage | contraction generate | occur | produced at the time of preliminary foaming of an expandable polylactic acid-type resin particle.
（比較例２）
ポリ乳酸系樹脂として、島津製作所社から商品名「ＬＡＣＴＹ ９０１０」で市販されている結晶性ポリ乳酸系樹脂（貯蔵弾性率曲線と損失弾性率曲線との交点Ａにおける温度Ｔ：１０１．７℃、交点Ａにおける貯蔵弾性率（損失弾性率）：１．０６×１０5 Ｐａ、融点：１４２．４℃）を用いたこと以外は実施例１と同様にしてポリ乳酸系樹脂発泡成形品を得た。
(Comparative Example 2)
As a polylactic acid resin, a crystalline polylactic acid resin commercially available from Shimadzu Corporation under the trade name “LACTY 9010” (temperature T at the intersection A between the storage elastic modulus curve and the loss elastic modulus curve: 101.7 ° C., A polylactic acid resin foam molded article was obtained in the same manner as in Example 1 except that the storage elastic modulus (loss elastic modulus) at the intersection A was 1.06 × 10 5 Pa and the melting point was 142.4 ° C. .
（比較例３）
ポリ乳酸系樹脂粒子に二酸化炭素をゲージ圧で１．０ＭＰａの圧力にて気相含浸したこと以外は実施例１と同様にしてポリ乳酸系樹脂発泡成形品を得ようとしたが、発泡性ポリ乳酸系樹脂粒子が発泡せず、ポリ乳酸系樹脂発泡成形品を得ることができなかった。
(Comparative Example 3)
A polylactic acid resin foamed molded product was obtained in the same manner as in Example 1 except that polylactic acid resin particles were vapor-phase impregnated with carbon dioxide at a gauge pressure of 1.0 MPa. The lactic acid resin particles did not foam, and a polylactic acid resin foam molded product could not be obtained.
（比較例４）
ポリ乳酸系樹脂粒子に二酸化炭素をゲージ圧で４．０ＭＰａの圧力にて気相含浸したこと以外は実施例１と同様にしてポリ乳酸系樹脂発泡成形品を得ようとしたが、ポリ乳酸系樹脂粒子への二酸化炭素の気相含浸時に、ポリ乳酸系樹脂粒子同士の合着が生じ、発泡性ポリ乳酸系樹脂粒子を得ることができなかった。
(Comparative Example 4)
A polylactic acid resin foam molded article was obtained in the same manner as in Example 1 except that polylactic acid resin particles were impregnated with carbon dioxide at a gauge pressure of 4.0 MPa. When the resin particles were impregnated with carbon dioxide in a gas phase, coalescence of the polylactic acid resin particles occurred, and foamable polylactic acid resin particles could not be obtained.
各実施例及び比較例で得られた発泡性ポリ乳酸系樹脂粒子及び発泡性ポリ乳酸系樹脂シート中における二酸化炭素量を測定した。更に、各実施例及び比較例で得られた予備発泡粒子及び予備発泡シートの嵩密度、平均気泡径を上述の要領で、外観性を下記の要領で測定すると共に、ポリ乳酸系樹脂発泡成形品の嵩密度、平均気泡径、ポリ乳酸系樹脂の結晶化度を上述の要領で、外観性及び加熱寸法変化率を下記の要領で測定した。これらの測定結果を表１及び表２に示した。なお、ポリ乳酸系樹脂発泡成形品の平均気泡径は、予備発泡体の平均気泡径の測定方法と同様の方法にて測定した。 The amount of carbon dioxide in the expandable polylactic acid resin particles and the expandable polylactic acid resin sheet obtained in each Example and Comparative Example was measured. Furthermore, while measuring the bulk density and the average cell diameter of the pre-expanded particles and the pre-expanded sheet obtained in each Example and Comparative Example as described above and the appearance as described below, the polylactic acid resin foam-molded article The bulk density, the average cell diameter, and the crystallinity of the polylactic acid resin were measured as described above, and the appearance and heating dimensional change rate were measured as described below. These measurement results are shown in Tables 1 and 2. In addition, the average cell diameter of the polylactic acid-based resin foam molded article was measured by the same method as the method for measuring the average cell diameter of the preliminary foamed product.
（予備発泡粒子及び予備発泡シートの外観性）
得られた予備発泡粒子及び予備発泡シートの外観を目視観察し、下記基準に基づいて判断した。
○・・・予備発泡粒子及び予備発泡シートに収縮は発生していなかった。
△・・・予備発泡粒子及び予備発泡シートにやや収縮が発生していた。
×・・・予備発泡粒子及び予備発泡シートの収縮が著しかった。
(Appearance of pre-expanded particles and pre-expanded sheet)
The external appearance of the obtained pre-expanded particles and the pre-expanded sheet was visually observed and judged based on the following criteria.
○: No shrinkage occurred in the pre-foamed particles and the pre-foamed sheet.
Δ: Some shrinkage occurred in the pre-expanded particles and the pre-expanded sheet.
X: The shrinkage of the pre-foamed particles and the pre-foamed sheet was remarkable.
（ポリ乳酸系樹脂発泡成形品の外観性）
得られたポリ乳酸系樹脂発泡成形品の外観を目視観察し、下記基準に基づいて判断した。
○・・・ポリ乳酸系樹脂発泡成形品に収縮は発生していなかった。
△・・・ポリ乳酸系樹脂発泡成形品にやや収縮が発生していた。
×・・・ポリ乳酸系樹脂発泡成形品の収縮が著しかった。
(Appearance of polylactic acid resin foam molding)
The appearance of the obtained polylactic acid-based resin foamed molded article was visually observed and judged based on the following criteria.
○: No shrinkage occurred in the polylactic acid resin foam molded product.
Δ: Some shrinkage occurred in the polylactic acid resin foam molded product.
X: The shrinkage of the polylactic acid resin foamed molded article was remarkable.
（加熱寸法変化率）
ポリ乳酸系樹脂発泡成形品の加熱寸法変化率は、ＪＩＳ Ｋ６７６７：１９９９「発泡プラスチック−ポリエチレン−試験方法」のＢ法に準拠して測定されたものをいう。具体的には、ポリ乳酸系樹脂発泡成形品を製造直後に５０℃の雰囲気下にて６時間に亘って放置して養生した。
(Heating dimensional change rate)
The heating dimensional change rate of the polylactic acid-based resin foam molded article refers to that measured in accordance with method B of JIS K6767: 1999 “Foamed plastic-polyethylene test method”. Specifically, the polylactic acid-based resin foam molded article was allowed to cure for 6 hours in an atmosphere of 50 ° C. immediately after production.
次に、ポリ乳酸系樹脂発泡成形品から一辺が１５０ｍｍの平面正方形状の試験片を切り出した。この試験片の表面中央部に、この試験片における任意の一辺に対して平行に、長さ５０ｍｍの直線を三本、５０ｍｍ間隔毎に描くと共に、これら三本の直線に対して直交する方向に長さ５０ｍｍの直線を５０ｍｍ間隔毎に三本、描いた。 Next, a flat square test piece having a side of 150 mm was cut out from the polylactic acid resin foam molded product. At the center of the surface of the test piece, three straight lines with a length of 50 mm are drawn at intervals of 50 mm in parallel to any one side of the test piece, and in a direction perpendicular to the three straight lines. Three straight lines each having a length of 50 mm were drawn at intervals of 50 mm.
得られた試験片を１２０℃の雰囲気中に２２時間に亘って放置した後に、６本の直線の長さを測定して、これら６本の直線の長さを相加平均し、得られた相加平均値Ｌから下記式に基づいて加熱寸法変化率を算出した。 After the obtained test piece was left in an atmosphere of 120 ° C. for 22 hours, the length of the six straight lines was measured, and the length of these six straight lines was arithmetically averaged. The heating dimensional change rate was calculated from the arithmetic mean value L based on the following formula.
Claims (3)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2005319824A JP4820623B2 (en) | 2005-11-02 | 2005-11-02 | Method for producing foamable polylactic acid resin |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2005319824A JP4820623B2 (en) | 2005-11-02 | 2005-11-02 | Method for producing foamable polylactic acid resin |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2007126539A true JP2007126539A (en) | 2007-05-24 |
| JP4820623B2 JP4820623B2 (en) | 2011-11-24 |
Family
ID=38149456
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2005319824A Expired - Fee Related JP4820623B2 (en) | 2005-11-02 | 2005-11-02 | Method for producing foamable polylactic acid resin |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4820623B2 (en) |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2012026557A1 (en) * | 2010-08-25 | 2012-03-01 | ダイキン工業株式会社 | Seal member |
| US8609774B2 (en) | 2010-08-25 | 2013-12-17 | Daikin Industries, Ltd. | Belt |
| US8754161B2 (en) | 2010-08-25 | 2014-06-17 | Daikin Industries, Ltd. | Complex-shaped fluororubber formed product |
| US8962706B2 (en) | 2010-09-10 | 2015-02-24 | Lifoam Industries, Llc | Process for enabling secondary expansion of expandable beads |
| US9006328B2 (en) | 2010-08-25 | 2015-04-14 | Daikin Industries, Ltd. | Fluororubber composition |
| US9045614B2 (en) | 2010-08-25 | 2015-06-02 | Daikin Industries, Ltd. | Fluororubber composition |
| JP2015531415A (en) * | 2012-09-05 | 2015-11-02 | バイオポリマー ネットワーク リミテッド | Production of polylactic acid foam using liquid carbon dioxide |
| US10518444B2 (en) | 2010-07-07 | 2019-12-31 | Lifoam Industries, Llc | Compostable or biobased foams |
| US11054066B2 (en) | 2010-08-25 | 2021-07-06 | Daikin Industries, Ltd. | Hose |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000136261A (en) * | 1998-08-28 | 2000-05-16 | Mitsui Chemicals Inc | Foaming particle and production of the same |
| JP2001342279A (en) * | 2000-05-31 | 2001-12-11 | Nishikawa Rubber Co Ltd | Method for expanding lactic acid-based polymer |
| JP2004083890A (en) * | 2002-07-01 | 2004-03-18 | Jsp Corp | Polylactic acid foamed particle and molded product of the polylactic acid foamed particle |
-
2005
- 2005-11-02 JP JP2005319824A patent/JP4820623B2/en not_active Expired - Fee Related
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2000136261A (en) * | 1998-08-28 | 2000-05-16 | Mitsui Chemicals Inc | Foaming particle and production of the same |
| JP2001342279A (en) * | 2000-05-31 | 2001-12-11 | Nishikawa Rubber Co Ltd | Method for expanding lactic acid-based polymer |
| JP2004083890A (en) * | 2002-07-01 | 2004-03-18 | Jsp Corp | Polylactic acid foamed particle and molded product of the polylactic acid foamed particle |
Cited By (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10518444B2 (en) | 2010-07-07 | 2019-12-31 | Lifoam Industries, Llc | Compostable or biobased foams |
| WO2012026557A1 (en) * | 2010-08-25 | 2012-03-01 | ダイキン工業株式会社 | Seal member |
| CN103080616A (en) * | 2010-08-25 | 2013-05-01 | 大金工业株式会社 | Seal member |
| US8609774B2 (en) | 2010-08-25 | 2013-12-17 | Daikin Industries, Ltd. | Belt |
| US8754161B2 (en) | 2010-08-25 | 2014-06-17 | Daikin Industries, Ltd. | Complex-shaped fluororubber formed product |
| US9006328B2 (en) | 2010-08-25 | 2015-04-14 | Daikin Industries, Ltd. | Fluororubber composition |
| US9045614B2 (en) | 2010-08-25 | 2015-06-02 | Daikin Industries, Ltd. | Fluororubber composition |
| US9068653B2 (en) | 2010-08-25 | 2015-06-30 | Daikin Industries, Ltd. | Sealing material |
| US11054066B2 (en) | 2010-08-25 | 2021-07-06 | Daikin Industries, Ltd. | Hose |
| US8962706B2 (en) | 2010-09-10 | 2015-02-24 | Lifoam Industries, Llc | Process for enabling secondary expansion of expandable beads |
| JP2015531415A (en) * | 2012-09-05 | 2015-11-02 | バイオポリマー ネットワーク リミテッド | Production of polylactic acid foam using liquid carbon dioxide |
Also Published As
| Publication number | Publication date |
|---|---|
| JP4820623B2 (en) | 2011-11-24 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP4820623B2 (en) | Method for producing foamable polylactic acid resin | |
| JP4446385B2 (en) | Multi-layer polylactic acid resin foam for thermoforming | |
| JP5004247B2 (en) | Polylactic acid expanded particle molded body | |
| US10167372B2 (en) | Manufacture of polylactic acid foams using liquid carbon dioxide | |
| TWI520995B (en) | Expanded polylactic acid resin beads and foamed molded article thereof | |
| JP2007100025A (en) | Polylactic acid-based resin expansion molded product | |
| EP2940070B1 (en) | Molded article of polylactic acid-based resin expanded beads | |
| JP4578309B2 (en) | Method for producing polylactic acid resin foam, method for producing polylactic acid resin foam molded article, and polylactic acid resin foam | |
| JP2004083890A (en) | Polylactic acid foamed particle and molded product of the polylactic acid foamed particle | |
| KR101859913B1 (en) | High strength extruded thermoplastic polymer foam | |
| JP5943826B2 (en) | Polyvinylidene fluoride-based resin expanded particles, method for producing polyvinylidene fluoride-based resin expanded particles, and molded article of polyvinylidene fluoride-based resin expanded particles | |
| JP6583909B2 (en) | Polylactic acid resin foamed molded article | |
| JP4761917B2 (en) | Process for producing pre-expanded particles of polylactic acid resin | |
| JP2005008776A (en) | Method for producing in-mold expansion molded product of polylactic acid-based resin and in-mold expansion molded product of polylactic acid-based resin | |
| US20220162377A1 (en) | Foam sheet, product, and method for producing foam sheet | |
| JP2010209224A (en) | Polyvinylidene fluoride resin expanded particle and polyvinylidene fluoride resin expanded particle molding | |
| JP2004277440A (en) | Polylactic acid foaming resin particle and foam molded product | |
| KR101438032B1 (en) | Polylactic acid based-biodegradable polymer blends with excellent compatibility, manufacturing method of heat resistant foamed sheet thereof and foam-molding product thereby | |
| JP4816853B2 (en) | Polylactic acid-based expandable resin particles | |
| JP4570033B2 (en) | Method for producing polylactic acid resin foamed molded article and polylactic acid resin foamed sheet for thermoforming | |
| JP2011213906A (en) | Polylactic acid-based resin foaming particle, method for producing the same, and foamed molding | |
| JP2012188560A (en) | Polyester resin foamed particle, polyester resin foamed molded product using the foamed particle, and method of producing the molded product | |
| JP2006111704A (en) | Polylactic acid resin foam and its manufacturing method | |
| KR20200072357A (en) | Foam having low melting point resin and a molded product including the same | |
| WO2020046657A1 (en) | Process for forming polylactide expanded bead foam |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20080807 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20110512 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20110524 |
|
| A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20110721 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20110818 |
|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20110905 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20140909 Year of fee payment: 3 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 4820623 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| LAPS | Cancellation because of no payment of annual fees |