JP2009263483A - New biodegradable aliphatic polyester-based resin foamed particle molded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aliphatic polyester-based resin foamed particle molded article having gas permeability and water permeability, moreover biodegradability. <P>SOLUTION: The aliphatic polyester-based resin foamed particle molded article is made by using an aliphatic polyester-based resin foamed particle in a pillar shape of 1.2≤L/D≤5.0, and used for applying to vegetation tray etc. that requires gas permeability and water permeability, moreover biodegradability. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a foamed molded article of biodegradable aliphatic polyester resin particles having air permeability and water permeability.

  Up to now, foam containers made of PS or PP are supported as vegetation trays, vegetation pots, flower pots, hydroponics (seedlings / vegetables / flowers / plants) as foaming containers that require air permeability and water permeability. It is used in planting containers such as wood, foliage plant support materials, rooftop and wall greening support materials, flower arrangement support materials, water purification support materials, and heat insulation materials for living creatures.

  For example, when planting flowers and trees, grow alleys in planting containers that have been pre-molded with a synthetic resin material in a pot shape or tray shape, transport this directly to the desired planting site, and synthesize it at the planting site. It has been practiced to extract and plant from a resinous planting container.

  Such a method is not only good in workability, but the planting container does not decompose in the soil, so when planting it is necessary to pull out the plant from the planting container and grow it at this time The tip of the root was damaged, affecting the growth. Moreover, since many of the waste containers generated at every planting are hardly decomposable synthetic polymers, disposal has been a problem. Recently, many planting containers including a seedling pot using a molded body using a biodegradable resin or a natural material or a non-woven fabric have been proposed to solve such problems.

However, even in the case of a planting container using a biodegradable material, if the decomposition rate of the planting container is slow compared to the growth of roots, the grown seedling will rise along the side of the container and The result is a hindrance to growth. Moreover, not only biodegradable resin but the container which shape | molded the film and the sheet | seat is poor in water permeability, and in many cases affects the growth after planting. In order to overcome these disadvantages, a thin portion is made in a part of the container (Patent Document 1), a large number of holes are made in the bottom of the container (Patent Document 2, Patent Document 3), and a mesh is used (Patent Document 1). Document 4) has been proposed.

However, if there is no gap where the tip of the root enters even if it is thinned locally, the root will rise along the wall surface. Moreover, when many holes are opened in the bottom, the strength of the container is locally reduced. When a mesh is used, if the root grows and breaks through the mesh, if the biodegradation does not proceed sufficiently, the mesh may damage the root, which is not preferable.

  Moreover, in the case of a planting tray having a relatively large volume, since soil is piled up in the container, it becomes a heavy object during transportation and a load is applied during work. For this reason, methods aimed at reducing the weight by the foam shape have been proposed (Patent Document 5, Patent Document 6, and Patent Document 7).

  Since Patent Documents 5 and 6 are foams using biodegradable materials, they can be decomposed in the soil and reduced in weight, and can be drained appropriately by providing a slit hole at the bottom, but for growing plants. Since sufficient ventilation is not provided, no proposal has been made for a foam container for vegetation made of a biodegradable material ensuring sufficient ventilation and water permeability.

  Furthermore, foaming using a biodegradable material tends to make the foamed film thinner and improve biodegradability, but it still does not reach a level where it can be quickly decomposed in the soil after use.

On the other hand, there has been a foamed particle molded body made of polypropylene resin expanded particles having a large L / D so far, but it has not been used for applications that require biodegradability as well as air permeability and water permeability (Patent Document 7). .
JP 2000-000032 A Japanese Patent Laid-Open No. 10-042712 Japanese Patent Laid-Open No. 11-18585 JP 09-322658 A JP 2001-258399 A JP 2006-94709 A International Publication No. 2006/16478 Pamphlet

  An object of the present invention is to provide an aliphatic polyester-based resin expanded particle molded body having air permeability, water permeability, and biodegradability.

  As a result of intensive research to solve the above problems, the present inventors have good breathability and water permeability when using a molded article having a void structure using columnar foam particles having a specific L / D. Thus, the inventors have found that the problem of disposal after use can be solved by decomposing in the soil without inhibiting the growth of the plant, and the present invention has been completed.

That is, the first of the present invention relates to a molded article of aliphatic polyester resin foamed particles using aliphatic polyester resin foamed particles having a columnar shape with L / D of 1.2 or more and 5.0 or less. A preferred embodiment relates to the above-mentioned aliphatic polyester resin expanded particle molded body having a porosity of 10 to 50%. More preferably, the aliphatic polyester-based resin is represented by the formula (1): [—O—CHR ₁ —CH ₂ —CO—] (where R ₁ is an alkyl group represented by C _n H _{2n + 1} , and n is 1-15 integer)
The above-mentioned aliphatic polyester-based resin expanded particle molded body represented by the following polymer represented by: (hereinafter, poly (3-hydroxyalkanoate): abbreviated as P3HA), more preferably P3HA Poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (hereinafter abbreviated as PHBH), the above-mentioned aliphatic polyester resin foamed molded article, particularly preferably a copolymer component of PHBH It is related with the aliphatic polyester-type resin expanded particle molding of the said description whose poly (3-hydroxyhexanoate) is 1 mol%-20 mol% in a composition. In the second aspect of the present invention, when the foamed particles made of P3HA are filled in a mold, and the foamed particles are fused by thermoforming, water vapor having a temperature 25 ° C. or lower than the melting point of the foamed particles made of P3HA is used. It is related with the manufacturing method of the aliphatic polyester-type resin expanded particle molding in any one of Claims 1-5 characterized by the above-mentioned.

  According to the present invention, it is possible to provide an aliphatic polyester resin expanded particle molded body having air permeability, water permeability, and biodegradability.

  Hereinafter, the present invention will be described in more detail. The molded article of the aliphatic polyester-based resin foamed particle of the present invention is obtained by mixing a dispersant and a foaming agent into a resin composition obtained by adding a modifier such as an isocyanate compound, which contains an aliphatic polyester as a main component. It is obtained by obtaining foamed particles, filling the foamed particles in a mold, and molding. In the resin composition, as long as the effect of the present invention is not inhibited, additives such as a colorant, an antioxidant, an ultraviolet absorber, a plasticizer, a lubricant, a crystal, and the like other than the above-mentioned substances at the time of melt kneading. Nucleating agents, inorganic fillers, bubble regulators and the like can be added.

  The aliphatic polyester of the present invention is not particularly limited as long as it has biodegradability. For example, polyethylene succinate, polybutylene succinate, polybutylene succinate adipate, polybutylene succinate carbonate Polyester obtained by polycondensation of polyhydric alcohol such as polyhydric carboxylic acid or acid anhydride thereof, ε-caprolactone, β-propiolactone, γ-butyrolactone, δ-valerolactone, enanthlactone or 4-methyl Homopolymers or copolymers of various lactones such as caprolactone, 2,2,4-trimethylcaprolactone, 3,3,5-trimethylcaprolactone, copolymers, polylactic acid, poly (3-hydroxyalkanoate) (abbreviation: P3HA), etc. Is mentioned. Among these, poly (3-hydroxyalkanoate) is preferable from the viewpoint of biodegradability.

The poly (3-hydroxyalkanoate) of the present invention is a poly (3-hydroxyalkanoate), which is an aliphatic polyester having a repeating structure composed of a 3-hydroxyalkanoate represented by the formula (1) and produced from microorganisms. Hydroxyalkanoate).
[—CHR—CH 2 —CO—O—] Formula (1)
(Where R is an alkyl group represented by CnH2n + 1, and n is an integer from 1 to 15)

  As P3HA in the present invention, a homopolymer of the above-mentioned 3-hydroxyalkanoate or a copolymer such as a di-copolymer, tri-copolymer or tetra-copolymer comprising a combination of two or more different 3-hydroxyalkanoates of n Or a blend of two or more selected from these homopolymers and copolymers, among which n = 1 3-hydroxybutyrate, n = 2 3-hydroxyvalerate, n = 3 3-hydroxy From homopolymers such as hexanoate, 3-hydroxyoctanoate with n = 5, 3-hydroxyoctadecanoate with n = 15, or combinations of two or more 3-hydroxyalkanoate units with different n Or a copolymer of two or more selected from these homopolymers and copolymers. De product can be preferably used. More preferable P3HA is poly (3-hydroxybutyrate-co-3-hydroxyhexanoate), which is a copolymer of 3-hydroxybutyrate with n = 1 and 3-hydroxyhexanoate with n = 3 ( (Abbreviation: PHBH), and the composition ratio of 3-hydroxybutyrate / 3-hydroxyhexanoate = 99/1 to 80/20 (mol / mol) is more preferable. When the composition ratio of 3-hydroxybutyrate / 3-hydroxyhexanoate is larger than 99/1, there is no difference in melting point from polyhydroxybutyrate, which is a homopolymer, and it is necessary to heat process at a high temperature. In some cases, the molecular weight is drastically reduced due to thermal decomposition, making it difficult to control the quality. On the other hand, if the composition ratio of 3-hydroxybutyrate / 3-hydroxyhexanoate is smaller than 80/20, it may take a long time to recrystallize at the time of heat processing, resulting in poor productivity.

  In addition, in this invention, a foaming molding can be produced using the foaming particle formed by melt-blending 2 or more types of the said aliphatic polyester resin. Alternatively, two or more different foam particles may be mixed and foam-molded.

  The modifier of the present invention is not particularly limited as long as it can be appropriately adjusted to a melt characteristic that facilitates foam molding, but is preferably an isocyanate compound in terms of reactivity.

  Examples of the isocyanate compound in the present invention include those having two or more isocyanate groups in one molecule, and examples thereof include aromatic, alicyclic, and aliphatic isocyanates. Aromatic isocyanates include tolylene, diphenylmethane, naphthylene, tolidine, xylene, triphenylmethane-based isocyanate compounds, alicyclic isocyanates have isophorone, hydrogenated diphenylmethane-based isocyanate compounds, and aliphatic isocyanates have hexagonal structure. Examples include isocyanate compounds having a skeleton of methylene and lysine. Further, a combination of two or more of these isocyanate compounds can be used. However, from the viewpoint of versatility, handleability, weather resistance, etc., use of tolylene and diphenylmethane is preferable, and use of diisocyanate polyisocyanate is more preferable. The content of the isocyanate compound is preferably 1.5 to 5.5 parts by weight with respect to 100 parts by weight of the base resin made of an aliphatic polyester resin.

  Examples of the colorant of the present invention include black, gray, brown, blue, green, and other colored pigments or dyes, each of which has an organic type and an inorganic type. As such pigments and dyes, various conventionally known ones can be used, and at least one selected from these groups can be used.

  Examples of the antioxidant of the present invention include hindered phenol-based, phosphite-based, sulfur-based and phosphorus-based antioxidants, and at least one selected from these groups can be used.

  Examples of the ultraviolet absorber of the present invention include salicylic acid derivatives such as phenyl salicylate and p-tert-butylphenyl salicylate, benzophenones, benzotriazoles, zinc oxide-based ultraviolet stabilizers, hindered amines, etc., selected from these groups At least one of the above may be used.

  As the plasticizer of the present invention, glycerin derivatives, ether ester derivatives, glycolic acid derivatives, citric acid derivatives, adipic acid derivatives, rosin derivatives, tetrahydrofurfuryl alcohol derivatives, etc. from the viewpoint of compatibility with aliphatic polyester resins And at least one selected from these groups can be used.

  Examples of the lubricant of the present invention include fatty acid metal salts such as sodium stearate, magnesium stearate, calcium stearate and barium stearate, liquid paraffin, olefin wax, stearyl amide compound, etc., and at least selected from these groups One can be used.

  The crystallization nucleating agent of the present invention is not particularly limited as long as the crystallization accelerating effect can be obtained with respect to the aliphatic polyester-based resin. For example, organic substances such as PHB and amide compounds, talc and the like In view of compatibility with aliphatic polyester resins, crystallization promoting effect, and biodegradability, PHB is preferable. In order to obtain the maximum crystallization promoting effect, it is more preferable that the crystallization nucleating agent has a small particle size.

  Examples of the inorganic filler of the present invention include inorganic compounds such as silica, talc, calcium silicate, wollastonite, kaolin, clay, mica, zinc oxide, titanium oxide, and silicon oxide, and are selected from these groups. At least one can be used.

  Examples of the air conditioner of the present invention include inorganic nucleating agents such as talc, silica, calcium silicate, calcium carbonate, aluminum oxide, titanium oxide, diatomaceous earth, clay, baking soda, alumina, barium sulfate, aluminum oxide, and bentonite. , At least one selected from these groups can be used. The amount of the bubble regulator used is usually 0.005 to 2 parts by weight with respect to 100 parts by weight of the resin composition.

  Although the manufacturing example of the aliphatic polyester-type resin expanded particle molding of this invention is not necessarily limited, it illustrates below.

<Preparation of resin composition>
The resin composition of the present invention includes a base resin that is an aliphatic polyester resin such as P3HA, an isocyanate compound, and further, if necessary, a colorant such as a dye and a pigment, an antioxidant, an ultraviolet absorber, and a plasticizer. , After blending a predetermined amount of additives such as lubricants, crystallization nucleating agents, inorganic fillers, bubble regulators, etc., then heat melt kneading using an extruder, kneader, Banbury mixer, roll, etc. In this case, a strand is obtained from the die part at the tip of the extruder. The extruded strand is cut while adjusting the number of rotations of the pelletizer cutter to obtain a resin composition.

  In that case, L of L / D of this resin composition has preferable 0.1-5. If it is less than 0.1 mm, the foaming agent at the time of impregnation tends to volatilize. If it exceeds 5 mm, the resin foam particle size obtained also becomes large, so that the mold filling port may be clogged during foam molding. Moreover, in order to obtain the aliphatic polyester-based resin expanded particles having a columnar shape with L / D of 1.2 or more and 5.0 or less, L / D of the resin composition needs to be large. In that case, as an example of L / D of this resin composition, it is preferable to cut so that it may become 1.2 or more and 5.0 or less. L / D as referred to in the present invention refers to the maximum diameter per particle of the resin composition or resin expanded particles as D, the maximum length as L, and the value obtained by dividing the maximum length by the maximum diameter as L / D. .

<Aliphatic polyester resin expanded particle production process>
After dispersing the resin composition obtained above in a water-based dispersion medium in a closed container together with a dispersant, a foaming agent is introduced into the sealed container and heated above the softening temperature of the resin composition, if necessary. After holding for a certain period of time near the foaming temperature, for example, 5 minutes to 5 hours, one end of the sealed container is released, and the resin composition and the aqueous dispersion medium are removed from the pressure of the sealed container (for example, 0.05 to 20 MPa). Is released into a low-pressure atmosphere, and aliphatic polyester resin expanded particles having a columnar shape with an L / D of 1.2 or more and 5.0 or less are obtained. When L / D is less than 1.2, the porosity of the finally obtained aliphatic polyester resin expanded resin molded body may be too low. On the other hand, when L / D exceeds 5.0, when the foamed particles to be obtained are foam-molded, the mold filling port may be clogged with foamed particles.

  The L / D of the resin foam particles is preferably 0.2 to 20 mm. If it is less than 0.2 mm, the foaming agent at the time of impregnation tends to volatilize. On the other hand, if it exceeds 20 mm, the size of the resin foam particles obtained is increased, and therefore the mold filling port may be clogged during foam molding.

  Examples of the dispersing agent include inorganic substances such as tricalcium phosphate, calcium pyrophosphate, kaolin, basic magnesium carbonate, aluminum oxide, basic zinc carbonate, dodecylbenzene sulfonate sodium, α-olefin sulfonate sodium, normal paraffin sulfonate sodium. In combination with an anionic surfactant. The amount of the inorganic substance used is preferably 0.1 to 3.0 parts by weight with respect to 100 parts by weight of the resin composition, and the amount of the anionic surfactant used is 0.001 to 0.000 with respect to 100 parts by weight of the resin composition. 2 parts by weight is preferred. The dispersion medium is usually water from the viewpoint of economy and ease of handling, but is not limited to this as long as it is aqueous.

  Examples of the blowing agent include saturated hydrocarbons having 3 to 5 carbon atoms such as propane, normal butane, isobutane, normal pentane, isopentane, and neopentane, ethers such as dimethyl ether, diethyl ether, and methyl ethyl ether, monochloromethane, dichloromethane, Halogenated hydrocarbons such as dichlorodifluoroethane, inorganic gases such as carbon dioxide, nitrogen and air, water and the like can be mentioned, but at least one of these may be used. In view of environmental compatibility, foaming agents other than halogenated hydrocarbons are preferred. The amount of foaming agent added varies depending on the expansion ratio of the target pre-expanded particles, the type of foaming agent, the type of resin, the ratio of the resin particles to the dispersion medium, the space volume of the container, the impregnation or foaming temperature, etc. Usually, it is in the range of 2 to 10,000 parts by weight with respect to 100 parts by weight.

  The foamed particles obtained by the above method can be pressurized and aged with pressurized air if necessary to impart foaming ability to the foamed particles.

<Aliphatic polyester resin foamed particle molding process>
The foamed particles obtained by the above-described method are subjected to pressure aging and then filled into a mold, and then, by introducing water vapor into the mold, the foamed particles are heat-fused to produce a biodegradable aliphatic polyester resin. A foamed particle molded body is obtained.

  When fusing the expanded particles by thermoforming, it is preferable to use water vapor at a temperature 25 ° C. or more lower than the melting point of the aliphatic polyester resin expanded particles, and use water vapor at a temperature 25 to 80 ° C. lower than the melting point. Is more preferable. If the heat molding temperature is not lower by 25 ° C. or more than the melting point of the aliphatic polyester resin expanded particles, the finally obtained aliphatic polyester resin expanded particles may have a too low porosity.

The porosity of the aliphatic polyester-based resin expanded particle molded product referred to in the present invention refers to, for example, cutting the expanded particle molded product into a certain size, obtaining an apparent volume V1 from the outer dimensions, and further removing the same molded product with a certain amount of ethanol. Is immersed in a graduated cylinder and the increased volume V2 at that time is determined. The obtained numerical value is applied to Equation 2 below to calculate the porosity.
Void ratio (%) = {(V1−V2) / (V1)} × 100 (2)

  The porosity of the aliphatic polyester resin expanded resin molded article of the present invention is preferably 10 to 50%. If it is less than 10%, it may be difficult to ensure satisfactory water permeability and air permeability. Moreover, when it exceeds 50%, the fusion | melting property of foamed particles worsens, intensity | strength cannot be acquired and a molded object may be damaged.

  Aliphatic polyester resin foamed particle molded body of the present invention includes a vegetation tray, a vegetation pot, a flower pot, a support material for hydroponics (seedlings / vegetables / flowers / plants), a support material for foliage plants, a rooftop / wall greening Suitable for applications that require breathability, water permeability, and biodegradability, such as planting containers such as support materials, support materials for flower arrangements, support materials for water purification, heat insulation materials for living creatures, drain materials, etc. .

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. In the examples, “parts” are based on weight. Substances used in the present invention were abbreviated as follows.
P3HA: poly (3-hydroxyalkanoate)
PHBH: poly (3-hydroxybutyrate-co-3-hydroxyhexanoate)
HH ratio: mole fraction of hydroxyhexanoate in PHBH (mol%)

<L / D of resin composition and resin expanded particles>
The maximum diameter and the maximum length of the resin compositions and resin expanded particles obtained in Examples and Comparative Examples were measured with calipers, and L and L / D were calculated.

<Crystal melting temperature (Tm) of resin composition and resin expanded particles>
In the differential scanning calorimetry, about 5 mg of the resin composition in Examples and Comparative Examples was precisely weighed, and the differential scanning calorimeter (Seiko Denshi Kogyo Co., Ltd., SSC5200) was heated at a rate of temperature increase of 10 ° C./min. The temperature was raised from 200C to 200C, and the crystal melting temperature (Tm) was obtained from the obtained DSC curve.

<Method for measuring weight average molecular weight of resin composition>
The polystyrene conversion Mw of the resin composition in an Example and a comparative example was calculated | required by GPC measurement. The GPC device uses CCP & 8020 system (manufactured by Tosoh Corporation), the column is GPCK-805L (manufactured by Showa Denko), the column temperature is 40 ° C., 20 mg of each foamed resin particle is dissolved in 10 ml of chloroform, 200 μl is injected, and Mw is injected. Asked.

<Method for Measuring Foaming Ratio of Resin Foamed Particles and Resin Foamed Particle Molded Article>
A graduated cylinder containing ethanol at 23 ° C. was prepared, and 500 or more aliphatic polyester resin expanded particles (of the expanded particles group) were left in the graduated cylinder for 7 days at a relative humidity of 50%, 23 ° C. and 1 atm. Weight W (g)) or the volume of the foam particles and the molded product from the rise in the ethanol liquid level when the molded product of the aliphatic polyester resin expanded particle cut out to an appropriate size is sunk using a wire mesh or the like. V (cm ³ ) was read. The expansion ratio of the expanded particles and the molded body was calculated from the weight W (g) of the expanded particle group, the volume V (cm ³ ) of the expanded particle group and the molded body, and the resin density ρ (g / cm ³ ) by the following equation.

Foaming ratio = V / (W / ρ)
<Method for measuring closed cell ratio of resin foam particles and resin foam particle molding>
It measured according to ASTM D-2856 using a multi-pynometer (manufactured by Beckman Japan Co., Ltd.).

<Measurement of porosity of molded resin particles>
First, peel off 5 mm each from the surface of the aliphatic polyester resin expanded particle molded body obtained in Examples and Comparative Examples with a cutter, cut out 50 × 50 × 10 mm from the remaining expanded resin particle molded body, and apparent volume from the outer dimensions V1 a (cm ³⁾ was determined. Furthermore, the same sample was immersed in a graduated cylinder containing a certain amount of ethanol, and the increased volume V2 (cm ³ ) at that time was measured.
Void ratio (%) = {(V1−V2) / (V1)} × 100 (2)

<Water permeability evaluation of resin foam particle molding>
Aliphatic polyester resin expanded resin molded articles obtained in Examples and Comparative Examples were cut out to a size of 100 × 200 × 10 (mm), and observed for 3 minutes after placing water thereon. The evaluation criteria at that time are as follows. ○: Water is dropped on the surface of the molded body and water falls from the back surface of the molded body. ×: Water is dropped on the surface of the molded body, and water does not fall from the back surface of the molded body.

<Breathability evaluation of resin foam particle molding>
The foamed molded article of aliphatic polyester-based resin obtained in Examples / Comparative Examples was cut out to a size of 100 × 200 × 10 (mm), and the state when the breath was blown against the surface of the molded body was observed. did. The evaluation criteria at that time are as follows. ○: Breathing out from the back of the molded body, x: Breathing out from the back of the molded body.

<Biodegradability of resin foam particles>
The foamed aliphatic polyester resin particles obtained in Examples and Comparative Examples were embedded in soil having a depth of 10 cm, and after 6 months, the shape change was observed, and the degradability was evaluated according to the following criteria. ○: Decomposed so that a considerable part is decomposed and it is difficult to confirm the shape. ×: Foamed particles are observed with almost no change in shape, and are not decomposed.

(Production Example 1) Production of PHBH having a 3HH ratio of 7 mol% A transformant (PHB-4 / pJRDdmsEE32d13) is used as a production strain. The production strain was obtained according to the following method. First, pARD215 (ATCC 37533, J. Davison, M. Heustersprite et al., Gene, 51,275-280 (1987)), a derivative of RSF1010, which is a broad host range vector, is cleaved with restriction enzyme Van91I, so that mobs A and B A DNA fragment of about 9.5 kb from which 3215-4075 of pJRD215, which is a part of the gene, was deleted, was obtained by using DNA Ligation Kit Ver. 1 (Takara Shuzo Co., Ltd.) was used for self-ligation to obtain plasmid pJRDdm. By cleaving the obtained pJRDdm with restriction enzymes EcoICRI and PshAI, about 1.5 kb of the streptomycin resistance gene (strA and strB genes) is deleted, and a blunt-ended DNA fragment of about 8.0 kb is obtained. This was self-ligated and the plasmid pJRDdms was obtained by deleting 206-1690 of pJRD215. After the obtained pJRDdms is cleaved with the restriction enzyme EcoRI, the modified gene fragment EE32d13 (see Japanese Patent Laid-Open No. 10-108682) of Aeromonas caviae is inserted into the EcoRI site of pJRDdms obtained above. The expression plasmid pJRDdmsEE32d13 was obtained. pJRDdmsEE32d13 was introduced into Ralstonia eutropha PHB-4 strain (DSM541, strain lacking polyester synthesis ability) by an electric pulse method to obtain a production strain (PHB-4 / pJRDdmsEE32d13).

  The composition of the seed medium is 1 w / v% Meat-extract, 1 w / v% Bacto-Trypton, 0.2 w / v% Yeast-extract, 0.9 w / v% Na2PO4 · 12H2O, 0.15 w / v% KH2PO4, (PH 6.8).

  The composition of the preculture medium is 1.1 w / v% Na2PO4 · 12H2O, 0.19 w / v% KH2PO4, 1.29 w / v% (NH4) 2SO4, 0.1 w / v% MgSO4 · 7H2O, 2.5 w / v% Palm W olein oil, 0.5v / v% trace metal salt solution (1.6w / v% FeCl3 · 6H2O in 0.1N hydrochloric acid, 1w / v% CaCl2 · 2H2O, 0.02w / v% CoCl2 · 6H2O , 0.016 w / v% CuSO4 · 5H2O, 0.012 w / v% NiCl2 · 6H2O). 5 × 10 −6 w / v% kanamycin.

  The composition of the polyester production medium is 0.385 w / v% Na2PO4 · 12H2O, 0.067 w / v% KH2PO4, 0.291 w / v% (NH4) 2SO4, 0.1 w / v% MgSO4 · 7H2O, 0.5 v / v % Trace metal salt solution (1.6 W / v% FeCl3 · 6H2O in 0.1N hydrochloric acid, 1 w / v% CaCl2 · 2H2O, 0.02 w / v% CoCl2 · 6H2O, 0.016 w / v% CuSO4 · 5H2O, 0 .012 w / v% NiCl2 · 6H2O dissolved), 0.05 w / v% BIOSPUREX200K (antifoaming agent: manufactured by Cognis Japan), 5 × 10-6 w / v% kanamycin. As a carbon source, palm kernel oil olein, which is a low melting point fraction obtained by separating palm kernel oil, is used as a single carbon source. Throughout the entire culture, the specific substrate supply rate is 0.08 to 0.1 (g oil) x (g It fed so that it might become (net dry microbial cell weight) -1x (h) -1.

  A glycerol stock (50 μl) of the production strain (PHB-4 / pJRDdmsEE32d13) was inoculated into a seed medium (10 ml) and cultured for 24 hours, and then a 3 L jar fermenter (Maruhishi Bioengineer) containing 1.8 L of a preculture medium. MDL-300 manufactured) was inoculated at 1.0 v / v%. The operating conditions were a culture temperature of 30 ° C., a stirring speed of 500 rpm, an aeration rate of 1.8 L / min, and a culture for 28 hours while controlling the pH between 6.7 and 6.8. A 7% aqueous ammonium hydroxide solution was used for pH control.

  In the polyester production culture, a 10 L jar fermenter (MDL-1000, manufactured by Maruhishi Bioengine) containing 6 L of production medium was inoculated with 5.0 v / v% of the preculture seed. The operating conditions were a culture temperature of 28 ° C., a stirring speed of 400 rpm, an aeration rate of 3.6 L / min, and a pH controlled between 6.7 and 6.8. A 7% aqueous ammonium hydroxide solution was used for pH control. Culturing was carried out for about 64 hours. After completion of the cultivation, the cells were collected by centrifugation, washed with methanol, lyophilized, and the weight of the dried cells was measured.

  To about 1 g of the obtained dried cells, 100 ml of chloroform was added and stirred overnight at room temperature to extract PHBH in the cells. The bacterial cell residue was filtered off and concentrated with an evaporator until the total volume reached about 30 ml. Then, about 90 ml of hexane was gradually added, and the mixture was allowed to stand for 1 hour with slow stirring. The precipitated PHBH was filtered off and then vacuum dried at 50 ° C. for 3 hours. The dry PHBH was subjected to 3HH composition analysis and molecular weight measurement by the following analysis.

<Analysis of 3HH composition (mol%) of PHBH>
The 3HH composition analysis of the produced PHBH was measured by gas chromatography as follows. To 20 mg of dry PHBH, 2 ml of a sulfuric acid-methanol mixture (15:85) and 2 ml of chloroform were added and sealed, and heated at 100 ° C. for 140 minutes to obtain a methyl ester of a PHBH decomposition product. After cooling, 1.5 g of sodium bicarbonate was added little by little to neutralize it, and the mixture was allowed to stand until the generation of carbon dioxide gas stopped. After adding 4 ml of diisopropyl ether and mixing well, the mixture was centrifuged and the monomer unit composition of the PHBH degradation product in the supernatant was analyzed by capillary gas chromatography. The gas chromatograph used was Shimadzu Corporation GC-17A, and the capillary column used was GL Science's NEUTRA BOND-1 (column length 25 m, column inner diameter 0.25 mm, liquid film thickness 0.4 μm). He was used as the carrier gas, the column inlet pressure was 100 kPa, and 1 μl of the sample was injected. As temperature conditions, the temperature was raised from the initial temperature of 100 to 200 ° C. at a rate of 8 ° C./min, and further from 200 to 290 ° C. at the rate of 30 ° C./min. As a result of analysis under the above conditions, the 3HH composition of PHBH at the end of the 96-hour culture was 7 mol% on average.

<Weight average molecular weight (Mw) analysis of PHBH>
The weight average molecular weight (Mw) analysis of PHBH was performed by gel permeation chromatography. About 15 mg of extracted PHBH was dissolved in 10 ml of chloroform, filtered through a 0.2 μm filter to obtain a measurement sample, and 0.05 ml of the sample was analyzed. The measurement system was SLC-10A (manufactured by Shimadzu Corporation), and the column was connected with two Shodex GPC K-806L (manufactured by Showa Denko) in series, and measurements were made at 40 ° C. The moving layer was chloroform at 1.0 ml / min, and an RI detector (RID-10A, manufactured by Shimadzu Corporation) was used. As a standard product, polystyrene treated in the same manner (manufactured by Showa Denko, weight average molecular weight: about 7 million, about 1.70 million, 150,000, 30,000) was calculated by a calibration curve. As a result, the weight average molecular weight of PHBH was 700,000. Met.

Example 1
100 parts by weight of PHBH (Tm 135 ° C., Mw 700,000, specific gravity 1.2 g / ml) having a 3HH ratio of 7 mol%, and 2 parts by weight of a polyisocyanate compound (manufactured by Nippon Polyurethane, Millionate MR-200 (isocyanate groups 2.7 to 2.8) Equivalent / mol)) is hand-blended with a 30 mmφ twin screw extruder (Ikegai Seisakusho, PCM30) at a cylinder temperature of 150 ° C. and extruded from a 3 mmφ small hole die attached to the tip of the extruder. A resin composition having an L / D of 2.4, an L of 3.1 mm, and a melting point of 138 ° C. was prepared from the prepared strand while adjusting the number of revolutions of the pelletizer.

  After charging 100 parts by weight of the resin composition into a 4.5 L pressure vessel, adding 25 parts by weight of isobutane as a foaming agent, stirring, and raising the temperature until the temperature in the container reaches 119 ° C. (foaming temperature) After holding for 1 hour in a state where the internal pressure of the container is 2.5 MPa, the foam is discharged and foamed under atmospheric pressure through a small hole nozzle provided in the lower part of the pressure-resistant container. L / D: 2.2, L: 7.7 mm, foaming ratio Was 15 times, closed cell ratio was 98%, and an aliphatic polyester resin expanded particle having a melting point of 146 ° C was obtained.

  The aliphatic polyester-based resin expanded particles are filled into a 300 × 400 × 20 mm mold, 0.06-0.10 MPa (about 86-100 ° C.) water vapor is introduced into the mold, and the resin expanded particles are heated. By fusion-bonding, an aliphatic polyester resin expanded particle molded body having a porosity of 18%, an expansion ratio of 15 times, and an closed cell ratio of 95% was obtained. Since it has a void structure, air permeability and water permeability were confirmed. Further, the biodegradability of the aliphatic polyester resin expanded particles was good. The evaluation results of the expanded particles and the molded product are shown in Table 1.

(Example 2)
A resin composition was obtained in the same manner as in Example 1 except that the number of rotations of the pelletizer cutter was adjusted to L / D: 3.2. The resin composition was foamed in the same manner as in Example 1 to obtain aliphatic polyester resin expanded particles having an L / D of 3.0, an expansion ratio of 12 times, a closed cell ratio of 99%, and a melting point of 144 ° C. After filling the aliphatic polyester-based resin expanded particles into the mold, 0.06 to 0.10 MPa (about 86 to 100 ° C.) water vapor is introduced into the mold, and the expanded resin particles are heated and fused, and the porosity is increased. An aliphatic polyester resin expanded particle molded body having 30%, an expansion ratio of 12 times, and a closed cell ratio of 99% was obtained. Since it has a void structure, air permeability and water permeability were confirmed. Further, the biodegradability of the aliphatic polyester resin expanded particles was good. The evaluation results of the expanded particles and the molded product are shown in Table 1.

(Comparative Example 1)
A resin composition was obtained in the same manner as in Example 1 except that the rotation speed of the cutter of the pelletizer was adjusted to L / D: 1.1.
The resin composition was foamed in the same manner as in Example 1 to obtain aliphatic polyester resin expanded particles having an L / D of 1.1, an expansion ratio of 12 times, a closed cell ratio of 99%, and a melting point of 144 ° C. After filling the aliphatic polyester-based resin expanded particles into the mold, water vapor of 0.25 to 0.30 MPa (about 127 to 130 ° C.) is introduced into the mold, the resin expanded particles are heated and fused, and the porosity is increased. An aliphatic polyester resin expanded particle molded body having 0%, an expansion ratio of 12 times, and a closed cell ratio of 99% was obtained. Since there was no gap, air permeability and water permeability could not be confirmed. Further, the biodegradability of the aliphatic polyester resin expanded particles was good. The evaluation results of the expanded particles and the molded product are shown in Table 1.

Claims (6)

  An aliphatic polyester-based resin expanded particle molded body using aliphatic polyester-based resin expanded particles having a columnar shape having an L / D of 1.2 or more and 5.0 or less.   The aliphatic polyester resin expanded resin molded article according to claim 1, wherein the porosity is 10 to 50%. The aliphatic polyester-based resin expanded particle molded body according to claim 1 or 2, wherein the aliphatic polyester-based resin is represented by the following formula (1).
Formula (1)
[—O—CHR ₁ —CH ₂ —CO—] (1)
(Where R ₁ is an alkyl group represented by C _n H _{2n + 1} , and n is an integer of 1 to 15)
A polymer comprising at least one unit represented by the following (hereinafter referred to as poly (3-hydroxyalkanoate): abbreviated as P3HA)   The aliphatic polyester-based resin expanded particle molded body according to claim 3, wherein P3HA is poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) (hereinafter abbreviated as PHBH).   The aliphatic polyester-based resin expanded particle molded article according to claim 4, wherein poly (3-hydroxyhexanoate) is 1 mol% to 20 mol% in the composition of the copolymerization component of PHBH.   The foamed particles made of P3HA are filled in a mold, and when the foamed particles are fused by thermoforming, steam having a temperature lower by 25 ° C. or more than the melting point of the foamed particles made of P3HA is used. 5. A method for producing an aliphatic polyester resin expanded particle molded body according to any one of 5 above.