JPH08259723A - Biodegradable foam - Google Patents
Biodegradable foamInfo
- Publication number
- JPH08259723A JPH08259723A JP12986195A JP12986195A JPH08259723A JP H08259723 A JPH08259723 A JP H08259723A JP 12986195 A JP12986195 A JP 12986195A JP 12986195 A JP12986195 A JP 12986195A JP H08259723 A JPH08259723 A JP H08259723A
- Authority
- JP
- Japan
- Prior art keywords
- foam
- polylactic acid
- molar ratio
- copolymer
- biodegradable
- 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.)
- Pending
Links
- 239000006260 foam Substances 0.000 title claims abstract description 29
- 229920000747 poly(lactic acid) Polymers 0.000 claims abstract description 21
- 239000004626 polylactic acid Substances 0.000 claims abstract description 21
- 229920001577 copolymer Polymers 0.000 claims abstract description 12
- UQDJGEHQDNVPGU-UHFFFAOYSA-N serine phosphoethanolamine Chemical compound [NH3+]CCOP([O-])(=O)OCC([NH3+])C([O-])=O UQDJGEHQDNVPGU-UHFFFAOYSA-N 0.000 claims description 16
- 239000000155 melt Substances 0.000 claims description 2
- 239000000463 material Substances 0.000 description 6
- -1 polyethylene, ethylene Polymers 0.000 description 5
- 229920002988 biodegradable polymer Polymers 0.000 description 4
- 239000004621 biodegradable polymer Substances 0.000 description 4
- 238000010097 foam moulding Methods 0.000 description 4
- 239000011810 insulating material Substances 0.000 description 4
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 description 3
- 239000004793 Polystyrene Substances 0.000 description 3
- 229920002472 Starch Polymers 0.000 description 3
- 239000003607 modifier Substances 0.000 description 3
- 229920002223 polystyrene Polymers 0.000 description 3
- 238000011084 recovery Methods 0.000 description 3
- 239000008107 starch Substances 0.000 description 3
- 235000019698 starch Nutrition 0.000 description 3
- ATRRKUHOCOJYRX-UHFFFAOYSA-N Ammonium bicarbonate Chemical compound [NH4+].OC([O-])=O ATRRKUHOCOJYRX-UHFFFAOYSA-N 0.000 description 2
- LCGLNKUTAGEVQW-UHFFFAOYSA-N Dimethyl ether Chemical compound COC LCGLNKUTAGEVQW-UHFFFAOYSA-N 0.000 description 2
- AEMRFAOFKBGASW-UHFFFAOYSA-N Glycolic acid Chemical compound OCC(O)=O AEMRFAOFKBGASW-UHFFFAOYSA-N 0.000 description 2
- JVTAAEKCZFNVCJ-REOHCLBHSA-N L-lactic acid Chemical compound C[C@H](O)C(O)=O JVTAAEKCZFNVCJ-REOHCLBHSA-N 0.000 description 2
- OFBQJSOFQDEBGM-UHFFFAOYSA-N Pentane Chemical compound CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 description 2
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- 239000011358 absorbing material Substances 0.000 description 2
- 235000012538 ammonium bicarbonate Nutrition 0.000 description 2
- 239000001099 ammonium carbonate Substances 0.000 description 2
- 239000001913 cellulose Substances 0.000 description 2
- 229920002678 cellulose Polymers 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 238000005187 foaming Methods 0.000 description 2
- 239000004088 foaming agent Substances 0.000 description 2
- NNPPMTNAJDCUHE-UHFFFAOYSA-N isobutane Chemical compound CC(C)C NNPPMTNAJDCUHE-UHFFFAOYSA-N 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 description 2
- 239000002689 soil Substances 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- VXNZUUAINFGPBY-UHFFFAOYSA-N 1-Butene Chemical compound CCC=C VXNZUUAINFGPBY-UHFFFAOYSA-N 0.000 description 1
- 229910000013 Ammonium bicarbonate Inorganic materials 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-M Bicarbonate Chemical class OC([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-M 0.000 description 1
- 239000004604 Blowing Agent Substances 0.000 description 1
- 229920001661 Chitosan Polymers 0.000 description 1
- 239000004338 Dichlorodifluoromethane Substances 0.000 description 1
- XOBKSJJDNFUZPF-UHFFFAOYSA-N Methoxyethane Chemical compound CCOC XOBKSJJDNFUZPF-UHFFFAOYSA-N 0.000 description 1
- 229920000331 Polyhydroxybutyrate Polymers 0.000 description 1
- 239000004743 Polypropylene Substances 0.000 description 1
- 239000004372 Polyvinyl alcohol Substances 0.000 description 1
- UIIMBOGNXHQVGW-DEQYMQKBSA-M Sodium bicarbonate-14C Chemical compound [Na+].O[14C]([O-])=O UIIMBOGNXHQVGW-DEQYMQKBSA-M 0.000 description 1
- 229920001963 Synthetic biodegradable polymer Polymers 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 229910052783 alkali metal Inorganic materials 0.000 description 1
- 235000012501 ammonium carbonate Nutrition 0.000 description 1
- MTAZNLWOLGHBHU-UHFFFAOYSA-N butadiene-styrene rubber Chemical compound C=CC=C.C=CC1=CC=CC=C1 MTAZNLWOLGHBHU-UHFFFAOYSA-N 0.000 description 1
- IAQRGUVFOMOMEM-UHFFFAOYSA-N butene Natural products CC=CC IAQRGUVFOMOMEM-UHFFFAOYSA-N 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 150000001735 carboxylic acids Chemical class 0.000 description 1
- NEHMKBQYUWJMIP-NJFSPNSNSA-N chloro(114C)methane Chemical compound [14CH3]Cl NEHMKBQYUWJMIP-NJFSPNSNSA-N 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 229910052570 clay Inorganic materials 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- PXBRQCKWGAHEHS-UHFFFAOYSA-N dichlorodifluoromethane Chemical compound FC(F)(Cl)Cl PXBRQCKWGAHEHS-UHFFFAOYSA-N 0.000 description 1
- 235000019404 dichlorodifluoromethane Nutrition 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 150000002170 ethers Chemical class 0.000 description 1
- 238000001125 extrusion Methods 0.000 description 1
- 235000013305 food Nutrition 0.000 description 1
- 230000009477 glass transition Effects 0.000 description 1
- 150000008282 halocarbons Chemical class 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 238000001746 injection moulding Methods 0.000 description 1
- 239000001282 iso-butane Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 244000005700 microbiome Species 0.000 description 1
- HWPKGOGLCKPRLZ-UHFFFAOYSA-M monosodium citrate Chemical compound [Na+].OC(=O)CC(O)(C([O-])=O)CC(O)=O HWPKGOGLCKPRLZ-UHFFFAOYSA-M 0.000 description 1
- 235000018342 monosodium citrate Nutrition 0.000 description 1
- 239000002524 monosodium citrate Substances 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- IJDNQMDRQITEOD-UHFFFAOYSA-N n-butane Chemical compound CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 description 1
- 229920005615 natural polymer Polymers 0.000 description 1
- 239000005022 packaging material Substances 0.000 description 1
- 238000012856 packing Methods 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 239000005015 poly(hydroxybutyrate) Substances 0.000 description 1
- 229920001610 polycaprolactone Polymers 0.000 description 1
- 239000004632 polycaprolactone Substances 0.000 description 1
- 229920001155 polypropylene Polymers 0.000 description 1
- 229920006327 polystyrene foam Polymers 0.000 description 1
- 229920002635 polyurethane Polymers 0.000 description 1
- 239000004814 polyurethane Substances 0.000 description 1
- 229920002451 polyvinyl alcohol Polymers 0.000 description 1
- 229920000915 polyvinyl chloride Polymers 0.000 description 1
- 239000004800 polyvinyl chloride Substances 0.000 description 1
- 239000011736 potassium bicarbonate Substances 0.000 description 1
- 229910000028 potassium bicarbonate Inorganic materials 0.000 description 1
- 235000015497 potassium bicarbonate Nutrition 0.000 description 1
- 229910000027 potassium carbonate Inorganic materials 0.000 description 1
- 235000011181 potassium carbonates Nutrition 0.000 description 1
- TYJJADVDDVDEDZ-UHFFFAOYSA-M potassium hydrogencarbonate Chemical compound [K+].OC([O-])=O TYJJADVDDVDEDZ-UHFFFAOYSA-M 0.000 description 1
- PWARIDJUMWYDTK-UHFFFAOYSA-M potassium;butanedioate;hydron Chemical compound [K+].OC(=O)CCC([O-])=O PWARIDJUMWYDTK-UHFFFAOYSA-M 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000002250 progressing effect Effects 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- 230000008929 regeneration Effects 0.000 description 1
- 238000011069 regeneration method Methods 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011342 resin composition Substances 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 150000003384 small molecules Chemical class 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- UJRAXLUXHBUNDO-UHFFFAOYSA-M sodium;hydron;oxalate Chemical compound [Na+].OC(=O)C([O-])=O UJRAXLUXHBUNDO-UHFFFAOYSA-M 0.000 description 1
- 229920001059 synthetic polymer Polymers 0.000 description 1
- 239000000454 talc Substances 0.000 description 1
- 229910052623 talc Inorganic materials 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
- Biological Depolymerization Polymers (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、分解性、特に生分解性
に優れた発泡体に関し、発泡シート、トレイ、容器、緩
衝材等を提供する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foam having excellent degradability, particularly biodegradability, and provides a foam sheet, a tray, a container, a cushioning material and the like.
【従来の技術】従来、発泡シート、トレイ、容器、緩衝
材、断熱材、保温材、吸音材等の発泡体はポリスチレ
ン、ポリエチレン、エチレン／酢酸ビニル共重合体、ポ
リプロピレン、ポリウレタン、スチレン／ブタジエンブ
ロック共重合体等から作られており、その使用量は膨大
な量に達する。一方、生分解性ポリマーには各種合成、
天然のポリマーが知られており、ポリヒドロキシブチレ
ート、ポリ乳酸、ポリカプロラクトン、セルロース、キ
トサン、澱粉等がある。また、加工が困難なセルロー
ス、澱粉等の改質剤としてポリビニルアルコール、ポリ
エチレン、エチレン／酢酸ビニル共重合体等が用いられ
ており、パルプ、澱粉の改質物がトレイや梱包材、緩衝
材として提案されている。2. Description of the Related Art Conventionally, foams such as foam sheets, trays, containers, cushioning materials, heat insulating materials, heat insulating materials, and sound absorbing materials are polystyrene, polyethylene, ethylene / vinyl acetate copolymers, polypropylene, polyurethane, styrene / butadiene blocks. It is made from copolymers and the amount used is enormous. On the other hand, various synthetic biodegradable polymers,
Natural polymers are known and include polyhydroxybutyrate, polylactic acid, polycaprolactone, cellulose, chitosan, starch and the like. In addition, polyvinyl alcohol, polyethylene, ethylene / vinyl acetate copolymer, etc. are used as modifiers for difficult-to-process cellulose, starch, etc. Proposed modified products of pulp and starch as trays, packing materials, and cushioning materials. Has been done.
【発明が解決しようとする課題】発泡体は、上記のよう
に種々の用途に多量の合成ポリマーが使用されている
が、これらのポリマーは分解性、特に生分解性がないた
め、廃棄したときに環境に長く存在し、今や環境上、生
態系上の大問題となっている。さらに、焼却時の焼却炉
の損傷、有害ガスの発生等の理由で発泡体の廃棄物処理
は社会問題ともなっている。また、回収再利用しようと
しても、発泡体は回収コストがかかり、回収時の熱劣化
などの問題があって、回収、再生は極めて困難である。
近年、生分解性ポリマーがいくつか供給されはじめ、用
途開発が進んでいる。生分解性ポリマーとは自然界にお
いて、微生物が関与し低分子化合物に分解するポリマー
で、容器、包装材、食品トレイ等多数の用途がある。し
かし、これまでに供給されている生分解性ポリマーには
成型法に制限があり、実用、特に発泡体には殆ど供され
ていない。また、成形性改良のために添加される改質材
には生分解性がなく、廃棄したときに改質材が環境に長
く残ることになる。これまで、発泡体として加工性、特
性にすぐれ、かつ分解の容易な素材は見出されていなか
った。As described above, a large amount of synthetic polymers are used in foams for various purposes. However, since these polymers are not degradable, especially biodegradable, when discarded, they are discarded. Has long existed in the environment, and is now a major environmental and ecological problem. Further, waste treatment of foams has become a social problem due to damage to the incinerator during incineration, generation of harmful gas, and the like. Further, even if it is attempted to recover and reuse, the foam has a high recovery cost, and there are problems such as heat deterioration at the time of recovery, and recovery and regeneration are extremely difficult.
In recent years, some biodegradable polymers have begun to be supplied and application development is progressing. A biodegradable polymer is a polymer that is naturally decomposed into low molecular weight compounds by microorganisms and has many uses such as containers, packaging materials, and food trays. However, the biodegradable polymers that have been supplied so far have limitations on the molding method, and are hardly provided for practical use, particularly for foams. Further, the modifier added to improve the moldability has no biodegradability, and the modifier remains in the environment for a long time when it is discarded. Up until now, no foaming material having excellent processability and characteristics and being easily decomposed has been found.
【０００２】[0002]
【課題を解決するための手段】本発明者は、Ｌ体とＤ体
の共重合体で、Ｌ体／Ｄ体（モル比）が５０／５０〜９
８／２であり、かつＪＩＳ−Ｋ７２１０に示されるメル
トフローインデックス（以下ＭＩ値と記す）が０．１〜
１０のポリ乳酸は、発泡射出成形、発泡押し出し加工、
さらに発泡シートの真空成形等が可能で、各種成型品に
加工でき、かつ、このものが弱アルカリ性の水、あるい
は土壌中で容易に分解することを見出し、本発明に到達
した。即ち、本発明は、Ｌ体とＤ体の共重合体で、Ｌ体
／Ｄ体（モル比）が５０／５０〜９８／２であり、かつ
ＭＩ値が０．１〜１０のポリ乳酸からなる生分解性発泡
体に関する。従来からポリ乳酸としてはＬ体よりなるポ
リ乳酸、Ｌ−乳酸とグリコール酸の共重合体が知られて
いる。しかし、これらは発泡成形性、物性、生分解性と
も不十分である。本発明ではＬ体とＤ体の共重合体を用
いる。Ｌ体／Ｄ体（モル比）が５０／５０〜９８／２で
あるポリ乳酸が好ましい。Ｌ体／Ｄ体（モル比）が５０
／５０未満ではポリ乳酸はガラス転移温度が低く軟らか
すぎ、発泡体として実用に適さない。また、Ｌ体／Ｄ体
（モル比）が９８／２を超えると結晶性が増し、硬く、
加工性、分解性、特に生分解性に乏しいものとなる。特
に好ましいＬ体／Ｄ体のモル比は６０／４０〜９５／５
である。本発明に用いるポリ乳酸のＭＩ値は０．１〜１
０、好ましくは０．２〜６である。ＭＩ値が０．１未満
では発泡成形時に樹脂の流動性が十分でなく発泡困難で
ある。また、ＭＩ値が１０を超えると逆に流動性が良す
ぎて発泡が困難となる。本発明において、ポリ乳酸の発
泡成形は、ポリスチレン等で通常用いられている発泡成
形装置を用いて行うことができる。発泡剤としては、プ
ロパン、ｎ−ブタン、イソブタン、ペンタン、ブテン等
の炭化水素類、塩化メチル、塩化メチレン、ジクロロジ
フルオロメタン等のハロゲン化炭化水素類、ジメチルエ
ーテル、メチルエチルエーテル等のエーテル類等が用い
られ、これら発泡剤を１種、若しくは２種以上を組み合
わせて、ポリ乳酸１００重量部に対し、１〜２０重量部
加えて用いる。気泡調節剤には、クレー、タルク、シリ
カ等の無機微粉末、あるいはクエン酸モノナトリウム、
コハク酸モノカリウム、シュウ酸モノナトリウム等の多
価カルボン酸の酸性アルカリ金属塩、炭酸ナトリウム、
重炭酸ナトリウム、炭酸カリウム、重炭酸カリウム、炭
酸アンモニウム、重炭酸アンモニウム等の炭酸、重炭酸
塩およびこれらの組み合わせが挙げられる。これらの気
泡調節剤は、発泡体の所望する気泡の大きさによって適
宜使用されるが、本発明に用いるポリ乳酸に対しては、
ポリ乳酸１００重量部に対し、０．０２重量部以上用い
るのが好ましく、連続気泡を得やすくなる。０．０２重
量部未満では、気泡が粗大化し、良好な発泡体を得るこ
とは困難である。このようなポリ乳酸発泡体が有用な対
象物としては、容器、緩衝材、断熱材、保温材、吸音材
等が挙げられ、用途に応じ、シート状、小片状、あるい
はトレイ、カップ、箱等の成型品として用いられる。ま
た、他の生分解性ポリマー、あるいはポリ塩化ビニル、
ポリエチレン、エチレン／酢酸ビニル共重合体、ポリス
チレン等と複合して耐熱性や耐候性を付与することがで
きる。 〔作用〕Ｌ体とＤ体の共重合体で、Ｌ体／Ｄ体（モル
比）が５０／５０〜９８／２であり、かつＭＩ値が０．
１〜１０のポリ乳酸よりなる発泡体は、土壌と共存した
ときに容易に分解するため、廃棄しても分解して環境を
汚染しない。DISCLOSURE OF THE INVENTION The present inventor is a copolymer of L-form and D-form, and the L-form / D-form (molar ratio) is 50/50 to
8/2, and the melt flow index (hereinafter referred to as MI value) shown in JIS-K7210 is 0.1 to 0.1.
Polylactic acid of 10 is used for foam injection molding, foam extrusion,
Further, they have found that the foamed sheet can be vacuum-molded, etc., can be processed into various molded products, and that this can be easily decomposed in weakly alkaline water or soil, and thus reached the present invention. That is, the present invention is a copolymer of L-form and D-form, wherein L-form / D-form (molar ratio) is 50/50 to 98/2, and MI value is from polylactic acid of 0.1 to 10. To a biodegradable foam. Conventionally, as polylactic acid, polylactic acid consisting of L-form and copolymers of L-lactic acid and glycolic acid are known. However, they are insufficient in foam moldability, physical properties and biodegradability. In the present invention, a copolymer of L-form and D-form is used. Polylactic acid having an L-form / D-form (molar ratio) of 50/50 to 98/2 is preferable. L-form / D-form (molar ratio) is 50
When the ratio is less than / 50, polylactic acid has a low glass transition temperature and is too soft, and is not suitable for practical use as a foam. Further, when the L-form / D-form (molar ratio) exceeds 98/2, the crystallinity increases and the product becomes hard,
It has poor processability and degradability, especially biodegradability. A particularly preferred L-form / D-form molar ratio is 60/40 to 95/5.
Is. The MI value of polylactic acid used in the present invention is 0.1 to 1
It is 0, preferably 0.2 to 6. If the MI value is less than 0.1, the fluidity of the resin during foam molding is insufficient and it is difficult to foam. On the other hand, when the MI value exceeds 10, on the contrary, the fluidity is so good that foaming becomes difficult. In the present invention, the foam-molding of polylactic acid can be carried out using a foam-molding apparatus that is commonly used for polystyrene and the like. Examples of the blowing agent include hydrocarbons such as propane, n-butane, isobutane, pentane and butene, halogenated hydrocarbons such as methyl chloride, methylene chloride and dichlorodifluoromethane, ethers such as dimethyl ether and methyl ethyl ether. These foaming agents are used singly or in combination of two or more, and used by adding 1 to 20 parts by weight to 100 parts by weight of polylactic acid. As the foam control agent, fine inorganic powder such as clay, talc and silica, or monosodium citrate,
Acidic alkali metal salts of polyvalent carboxylic acids such as monopotassium succinate and monosodium oxalate, sodium carbonate,
Carbonates such as sodium bicarbonate, potassium carbonate, potassium bicarbonate, ammonium carbonate, ammonium bicarbonate, bicarbonates and combinations thereof. These cell regulators are appropriately used depending on the desired cell size of the foam, but for the polylactic acid used in the present invention,
It is preferable to use 0.02 parts by weight or more based on 100 parts by weight of polylactic acid, which facilitates obtaining open cells. If it is less than 0.02 part by weight, the cells become coarse and it is difficult to obtain a good foam. Objects in which such a polylactic acid foam is useful include containers, cushioning materials, heat insulating materials, heat insulating materials, sound absorbing materials, and the like, depending on the application, such as sheets, small pieces, or trays, cups, boxes. Used as a molded product such as. In addition, other biodegradable polymers, or polyvinyl chloride,
Heat resistance and weather resistance can be imparted by combining with polyethylene, ethylene / vinyl acetate copolymer, polystyrene and the like. [Action] A copolymer of L-form and D-form, L-form / D-form (molar ratio) is 50/50 to 98/2, and MI value is 0.
The foam made of polylactic acid of 1 to 10 easily decomposes when coexisting with soil, and therefore does not decompose even if discarded and does not pollute the environment.
【０００３】[0003]
【実施例】本発明に用いられるポリ乳酸の発泡成形加工
の一例は次に示される。ポリ乳酸、発泡剤、気泡調節剤
を押し出し機中にて加熱溶融、混練りし、低圧部へ押し
出す。この時、押し出し機ダイ内の樹脂組成物の温度を
１２０〜１８０℃、ダイ圧力を５０〜２００ｋｇ／ｃｍ
2 とする。ポリ乳酸の発泡倍率は１０〜５０倍となり、
連続気泡を有し、柔軟なものから高硬度のものまで、強
度の優れた生分解性発泡体を連続的に製造することがで
きる。１２０℃以下の温度、あるいは５０ｋｇ／ｃｍ2
以下の圧力で押し出すと、連続気泡率が低くなり、高発
泡体を得ることはできない。１８０℃以上の温度、ある
いは２００ｋｇ／ｃｍ2 以上の圧力では、気泡が粗大化
するとともに、萎縮して、同様に良好な発泡体を得るこ
とができない。このポリ乳酸発泡体をコンポスト化した
ところ、１ヶ月で形態を留めなくなり、良好な生分解性
を示した。EXAMPLES An example of the foam molding process of polylactic acid used in the present invention is shown below. Polylactic acid, a foaming agent, and a foam control agent are heated and melted in an extruder, kneaded, and extruded to a low pressure section. At this time, the temperature of the resin composition in the extruder die is 120 to 180 ° C., and the die pressure is 50 to 200 kg / cm.
Assume 2 . The expansion ratio of polylactic acid is 10 to 50 times,
It is possible to continuously manufacture a biodegradable foam having open cells and having excellent strength from flexible ones to high hardness ones. Temperature below 120 ℃, or 50kg / cm 2
If extruded under the following pressure, the open cell ratio becomes low, and a high foam cannot be obtained. At a temperature of 180 ° C. or higher, or a pressure of 200 kg / cm 2 or higher, the cells become coarse and shrink, and similarly good foam cannot be obtained. When this polylactic acid foam was composted, its shape was not retained in one month and good biodegradability was exhibited.
【０００４】[0004]
【発明の効果】Ｌ体とＤ体の共重合体で、Ｌ体／Ｄ体
（モル比）が５０／５０〜９８／２であり、かつＭＩ値
が０．１〜１０のポリ乳酸よりなる発泡体は、廃棄して
も分解して環境を汚染しないため、従来のポリスチレン
発泡体等が引き起こしていた廃棄物処理の諸問題を解決
するものである。EFFECT OF THE INVENTION Copolymer of L-form and D-form, polylactic acid having L-form / D-form (molar ratio) of 50/50 to 98/2 and MI value of 0.1 to 10 The foam does not decompose even if it is discarded and does not pollute the environment, and thus solves various problems of waste treatment caused by the conventional polystyrene foam and the like.
Claims (1)
（モル比）が５０／５０〜９８／２であり、かつメルト
フローインデックスが０．１〜１０のポリ乳酸よりなる
事を特徴とする生分解性発泡体。1. A polylactic acid which is a copolymer of L-form and D-form and has an L-form / D-form (molar ratio) of 50/50 to 98/2 and a melt flow index of 0.1 to 10. A biodegradable foam characterized in that
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12986195A JPH08259723A (en) | 1995-03-20 | 1995-03-20 | Biodegradable foam |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12986195A JPH08259723A (en) | 1995-03-20 | 1995-03-20 | Biodegradable foam |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH08259723A true JPH08259723A (en) | 1996-10-08 |
Family
ID=15020091
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12986195A Pending JPH08259723A (en) | 1995-03-20 | 1995-03-20 | Biodegradable foam |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH08259723A (en) |
-
1995
- 1995-03-20 JP JP12986195A patent/JPH08259723A/en active Pending
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