JP7187338B2 - Poly(3-hydroxyalkanoate) resin composition - Google Patents

Description

The present invention relates to a resin composition containing poly(3-hydroxyalkanoate) and a method for producing the same.

In recent years, it has become a problem that plastic waste has a large impact on the global environment, such as the impact on the ecosystem, the generation of harmful gases when burned, and global warming due to the large amount of combustion heat, and the above problems can be solved. As a material, the development of biodegradable plastics is becoming popular. In particular, when the biodegradable plastic is produced from plant-derived raw materials, the carbon dioxide emitted when the biodegradable plastic is burned is originally in the air, and the carbon dioxide in the atmosphere does not increase. This is called carbon neutral, and under the Kyoto Protocol, which imposes carbon dioxide reduction targets, it is regarded as important and its active use is desired.

Recently, from the viewpoint of biodegradability and carbon neutrality, biodegradable aliphatic polyester resins have been attracting attention as plant-derived plastics, particularly polyhydroxyalkanoate (hereinafter sometimes referred to as PHA) resins, and further Among PHA resins, poly(3-hydroxybutyrate) homopolymer resin (sometimes called P3HB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer resin (P3HB3HV) ), poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) copolymer resin (sometimes referred to as P3HB3HH), poly (3-hydroxybutyrate-co-4-hydroxybutyrate) copolymer Poly(3-hydroxyalkanoates) (sometimes referred to as P3HA) such as polymeric resins (sometimes referred to as P3HB4HB) have received attention.

P3HA in general, and copolymer P3HA in particular, are prone to thermal decomposition, are inferior in melt-molding workability, and have problems in that the physical properties of the obtained molded articles are insufficient. Attempts have been made to solve such problems (see Patent Document 1, for example).

U.S. Pat. No. 6,201,083

However, it was still difficult to industrially manufacture a bottle container made of P3HA by extrusion blow molding with the conventional method. For example, in the method described in Patent Document 1, it was found that the range of temperature conditions that can be selected for stable extrusion blow molding is narrow, and the weight of the bottle container that can be manufactured is limited (for example, See the comparative example of the present application).

Therefore, the object of the present invention is to stably produce a bottle container under practical processing conditions by extrusion blow molding, select a range of temperature conditions applicable during extrusion blow molding, and select a weight of a bottle container that can be manufactured. An object of the present invention is to provide a wide range of resin compositions containing poly(3-hydroxyalkanoate) and a method for producing the same.

As a result of intensive studies by the present inventors to solve the above problems, according to a poly(3-hydroxyalkanoate)-containing resin composition in which the apparent melt viscosity and the drawdown ratio are controlled in a specific relationship, extrusion blow It was found that molding can stably produce bottle containers under practical processing conditions, and that the selection range of temperature conditions applicable to extrusion blow molding and the selection range of the weight of manufacturable bottle containers are widened. completed.

That is, the present invention provides, for example, the following inventions.

［２］ 前記溶融粘度が１０００（Ｐａ・ｓ）以上、２０００（Ｐａ・ｓ）以下である［１］に記載の樹脂組成物。
［３］ 前記ドローダウン時間が１５（ｓｅｃ）以上、８０（ｓｅｃ）以下である［１］又は［２］に記載の樹脂組成物。
［４］ ポリ（３－ヒドロキシアルカノエート）１００重量部とエステル化合物０重量部以上、５重量部以下と有機過酸化物０．０１重量部以上、０．８重量部以下との溶融混練物である［１］～［３］のいずれかに記載の樹脂組成物。
［５］ 押出ブロー成形によって、押出機のダイ設定温度１５０℃以上の温度条件で、重量５０ｇ以下のボトル容器を作製可能なダイ設定温度とボトル容器重量の範囲を示す成形可能領域が、１００（℃・ｇ）以上である、［１］～［４］のいずれかに記載の樹脂組成物。
［６］ エステル化合物が、ラジカル反応性の官能基を持たないエステル化合物である［１］～［５］のいずれかに記載の樹脂組成物。
［７］ ポリ（３－ヒドロキシアルカノエート）が、ポリ（３－ヒドロキシブチレート－コ－３－ヒドロキシバレレート）、ポリ（３－ヒドロキシブチレート－コ－３－ヒドロキシヘキサノエート）、ポリ（３－ヒドロキシブチレート－コ－３－ヒドロキシバレレート－コ－３－ヒドロキシヘキサノエート）、ポリ（３－ヒドロキシブチレート－コ－４－ヒドロキシブチレート）、ポリ（３－ヒドロキシブチレート－コ－３－ヒドロキシオクタノエート）及びポリ（３－ヒドロキシブチレート－コ－３－ヒドロキシデカノエート）からなる群より選択される少なくとも１種である［１］～［６］のいずれかに記載の樹脂組成物。
［８］ エステル化合物が、グリセリンエステル系化合物、二塩基酸エステル系化合物、アジピン酸エステル系化合物、ポリエーテルエステル系化合物及びイソソルバイドエステル系化合物からなる群より選択される少なくとも１種である［１］～［７］のいずれかに記載の樹脂組成物。
［９］ 押出ブロー成形用の、［１］～［８］のいずれかに記載の樹脂組成物。
［１０］ ［１］～［９］のいずれかに記載の樹脂組成物を成形してなる成形体。
［１１］ ボトル容器である［１０］に記載の成形体。
［１２］ ［１］～［９］のいずれかに記載の樹脂組成物を製造する方法であって、
ポリ（３－ヒドロキシアルカノエート）１００重量部とエステル化合物０重量部以上、５重量部以下と有機過酸化物０．０１重量部以上、０．８重量部以下とを押出機にて、樹脂温度が１２０℃以上、１９０℃以下の範囲にて溶融混練する工程を含む、製造方法。
［１３］ 押出機内を４０秒以上、７００秒以下の範囲にて滞留するように前記溶融混練を行なう、［１２］に記載の製造方法。
［１４］ ［１］～［９］のいずれかに記載の樹脂組成物を押出機中で溶融した後、環状ダイからチューブ形状に押出す工程、金型で前記チューブを両側面から挟み込む工程、及び、一端が閉じられた前記チューブに空気を吹込んでボトル形状に成形する工程、を含む、ボトル容器の製造方法。 [1] Contains 100 parts by weight of poly(3-hydroxyalkanoate) and 0 parts by weight or more and 5 parts by weight or less of an ester compound, and the ratio of the following melt viscosity (Pa s) and drawdown time (sec) is 2.0×10 ⁻² (sec/[Pa·s]) or more and 8.0×10 ⁻² (sec/[Pa·s]) or less.
Melt viscosity: Using a capillary rheometer, a barrel setting temperature of 170 ° C., a diameter (d) of 0.05 cm connected to the tip of a barrel with a radius (D) of 0.4775 cm, from an orifice with a capillary length (l) of 1 cm, The load (F) when extruding the molten resin composition at a volumetric flow rate (Q) of 0.716 cm ³ /min and a shear rate of 122 sec ⁻¹ was measured, and the apparent melt viscosity ( η).
Drawdown time: The time required for the resin composition discharged from the orifice to drop 20 cm when measuring the melt viscosity.

[2] The resin composition according to [1], wherein the melt viscosity is 1000 (Pa·s) or more and 2000 (Pa·s) or less.
[3] The resin composition according to [1] or [2], wherein the drawdown time is 15 (sec) or more and 80 (sec) or less.
[4] A melt-kneaded product of 100 parts by weight of poly(3-hydroxyalkanoate), 0 parts by weight or more and 5 parts by weight or less of an ester compound, and 0.01 parts by weight or more and 0.8 parts by weight or less of an organic peroxide. A resin composition according to any one of [1] to [3].
[5] By extrusion blow molding, the moldable region indicating the range of the die setting temperature and the bottle container weight that can produce a bottle container weighing 50 g or less under the temperature condition of the die setting temperature of the extruder of 150 ° C. or higher is 100 ( ° C.·g) or more, the resin composition according to any one of [1] to [4].
[6] The resin composition according to any one of [1] to [5], wherein the ester compound is an ester compound having no radical-reactive functional group.
[7] Poly (3-hydroxyalkanoate) is poly (3-hydroxybutyrate-co-3-hydroxyvalerate), poly (3-hydroxybutyrate-co-3-hydroxyhexanoate), poly ( 3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate), poly(3-hydroxybutyrate-co-4-hydroxybutyrate), poly(3-hydroxybutyrate-co -3-hydroxyoctanoate) and poly(3-hydroxybutyrate-co-3-hydroxydecanoate) according to any one of [1] to [6], which is at least one selected from the group consisting of of the resin composition.
[8] The ester compound is at least one selected from the group consisting of glycerin ester-based compounds, dibasic acid ester-based compounds, adipate-based compounds, polyether ester-based compounds, and isosorbide ester-based compounds [ 1] The resin composition according to any one of [7].
[9] The resin composition according to any one of [1] to [8] for extrusion blow molding.
[10] A molded article obtained by molding the resin composition according to any one of [1] to [9].
[11] The molded article according to [10], which is a bottle container.
[12] A method for producing the resin composition according to any one of [1] to [9],
100 parts by weight of poly(3-hydroxyalkanoate), 0 parts by weight or more and 5 parts by weight or less of an ester compound and 0.01 parts by weight or more and 0.8 parts by weight or less of an organic peroxide are extruded to a resin temperature A manufacturing method comprising a step of melt-kneading in the range of 120 ° C. or higher and 190 ° C. or lower.
[13] The production method according to [12], wherein the melt-kneading is performed so that the mixture stays in the extruder for 40 seconds or more and 700 seconds or less.
[14] A step of melting the resin composition according to any one of [1] to [9] in an extruder, then extruding it into a tube shape from an annular die, sandwiching the tube from both sides with a mold, and a method of manufacturing a bottle container, comprising the step of blowing air into the tube, one end of which is closed, to form a bottle shape.

Since the present invention has the above configuration, it has a narrow processing temperature range, low productivity, and poor extrusion blow moldability compared to general-purpose resins. Poly(3-hydroxyalkanoate) that can stably produce bottle containers under practical processing conditions, has a wide selection range of temperature conditions that can be applied during extrusion blow molding, and a wide selection range of weights for bottle containers that can be manufactured. It is possible to provide a resin composition containing and a method for producing the same. This allows bottle containers made of poly(3-hydroxyalkanoates) to be mass produced at high speed in various weights by extrusion blow molding.

1 is a graph [vertical axis: container weight (g), horizontal axis: die set temperature (° C.)] showing an example of a moldable region (° C.·g) and a calculation method thereof.

The resin composition of the present invention is a resin composition containing 100 parts by weight of poly(3-hydroxyalkanoate) as an essential component.

[Poly(3-hydroxyalkanoate) (P3HA)]
The poly(3-hydroxyalkanoate) in the resin composition of the present invention is a biodegradable aliphatic polyester (preferably a polyester containing no aromatic ring) and has the general formula: [-CHR-CH ₂ -CO- O—] (wherein R is an alkyl group represented by C _n H2 _n+1 , and n is an integer of 1 or more and 15 or less) as an essential repeating unit. It is a polyhydroxyalkanoate. Among them, the repeating unit is preferably contained in an amount of 50 mol% or more, more preferably 70 mol% or more, based on the total monomer repeating units (100 mol%). More specifically, P3HA includes, for example, poly(3-hydroxybutyrate) (P3HB), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P3HB3HV), poly(3-hydroxybutyrate- co-3-hydroxyhexanoate) (P3HB3HH), poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) (P3HB3HV3HH), poly(3-hydroxybutyrate- co-4-hydroxybutyrate) (P3HB4HB), poly(3-hydroxybutyrate-co-3-hydroxyoctanoate), poly(3-hydroxybutyrate-co-3-hydroxydecanoate), etc. be done. The poly(3-hydroxyalkanoate) in the resin composition of the present invention may have no double bond.

P3HA produced by microorganisms (microorganism-produced P3HA) is usually P3HA composed only of D-isomer (R-isomer) polyhydroxyalkanoic acid monomer units. Among the microbial P3HA, P3HB, P3HB3HH, P3HB3HV, P3HB3HV3HH, and P3HB4HB are preferable, and P3HB, P3HB3HH, P3HB3HV, and P3HB4HB are more preferable, because they are easily industrially produced.

When P3HA (especially P3HA produced by microorganisms) contains 3-hydroxybutanoic acid (3HB) repeating units as essential monomer units, the monomer composition ratio is 100 mol %), the 3-hydroxybutanoic acid (3HB) repeating unit is preferably 80 mol % or more and 99 mol % or less, more preferably 85 mol % or more and 97 mol % or less. When the composition ratio of the 3HB repeating unit is 80 mol % or more, the rigidity of P3HA is further improved, and the degree of crystallinity does not become too low, which tends to facilitate purification. On the other hand, when the composition ratio of 3HB repeating units is 99 mol % or less, flexibility tends to be further improved. The monomer composition ratio of P3HA can be measured by gas chromatography or the like (see, for example, International Publication No. 2014/020838).

Microorganisms that produce microbial P3HA are not particularly limited as long as they are capable of producing P3HAs. For example, Bacillus megaterium, which was discovered in 1925, was the first P3HB-producing fungus. Natural microorganisms such as Alcaligenes latus are known, and P3HB is accumulated in these microorganisms.

Examples of hydroxybutyrate- and other hydroxyalkanoate-producing bacteria include Aeromonas caviae, which is a P3HB3HV and P3HB3HH-producing bacterium, and Alcaligenes eutrophus, which is a P3HB4HB-producing bacterium. It has been known. In particular, regarding P3HB3HH, in order to increase the productivity of P3HB3HH, Alcaligenes eutrophus AC32 strain (Alcaligenes eutrophus AC32, FERM BP-6038) (T.Fukui, Y.Doi, J.Bateriol) into which the gene of the P3HA synthase group was introduced. ., 179, pp. 4821-4830 (1997)) are more preferred, and microbial cells obtained by culturing these microorganisms under appropriate conditions and accumulating P3HB3HH in the cells are used. In addition to the above, genetically modified microorganisms into which various P3HA synthesis-related genes have been introduced may be used according to the P3HA to be produced, or culture conditions including the type of substrate may be optimized.

The molecular weight of P3HA is not particularly limited as long as it exhibits substantially sufficient physical properties for the intended use. It is preferably 100,000 or more and 1,000,000 or less, more preferably 300,000 or more and 700,000 or less. By setting the weight average molecular weight to 50,000 or more, the strength of the bottle container tends to be further improved. On the other hand, by setting the weight average molecular weight to 3,000,000 or less, there is a tendency that workability is further improved and molding becomes easier. The P3HA is preferably a uniformly and moderately crosslinked P3HA, as described later, and the weight average molecular weight is a value measured before the P3HA is crosslinked.

The weight average molecular weight of P3HA after cross-linking is preferably 50,000 or more and 3,000,000 or less, more preferably 100,000 or more and 1,000,000 or less, still more preferably 300,000 or more and 700,000. It is below. A weight average molecular weight of 50,000 or more tends to lengthen the drawdown time. On the other hand, by setting the weight average molecular weight to 3,000,000 or less, there is a tendency that workability is further improved and molding becomes easier.

The method for measuring the weight average molecular weight is gel permeation chromatography (GPC) (manufactured by Showa Denko KK "Shodex GPC-101"), using polystyrene gel (manufactured by Showa Denko KK "Shodex K-804") as a column, It can be obtained as a molecular weight when converted to polystyrene using chloroform as a mobile phase. At this time, a calibration curve is prepared using polystyrene with weight average molecular weights of 31,400, 197,000, 668,000 and 1,920,000. As the column in the GPC, a column suitable for measuring the molecular weight may be used.

In the resin composition of the present invention, P3HA can be used singly or in combination of two or more.

The content of P3HA in the resin composition of the present invention is not particularly limited, but is preferably 20% by weight or more, more preferably 30% by weight or more, still more preferably 40% by weight or more, still more preferably 60% by weight or more. Preferably, it is 70% by weight or more. By setting the content of P3HA to 20% by weight or more, the biodegradability of the resin composition tends to be even better. Although the upper limit of the P3HA content is not particularly limited, it is preferably 100% by weight or less, more preferably 99% by weight or less, and still more preferably 98% by weight or less.

[Other resins]
The resin composition of the present invention may contain resins other than P3HA (sometimes referred to as "other resins"). The other resin is not particularly limited as long as it does not significantly lower the compatibility, molding processability and mechanical properties when molding the resin composition of the present invention, but the resin composition has biodegradability, which is a feature of P3HA. It is preferably a biodegradable resin when used for a demanding application. Other resins include, for example, an aliphatic polyester having a structure in which an aliphatic diol and an aliphatic dicarboxylic acid are polycondensed, and an aliphatic aromatic polyester having both an aliphatic compound and an aromatic compound as monomers. . Examples of the former include polyethylene succinate, polybutylene succinate (PBS), polyhexamethylene succinate, polyethylene adipate, polybutylene adipate, polyhexamethylene adipate, polybutylene succinate adipate (PBSA), polyethylene sebacate, poly butylene sebacate and the like. Examples of the latter include poly(butylene adipate-co-butylene terephthalate) (PBAT), poly(butylene sebacate-co-butylene terephthalate), poly(butylene azelate-co-butylene terephthalate), poly(butylene succinate- co-butylene terephthalate) (PBST) and the like. In addition, another resin can also be used individually by 1 type, and can also be used in combination of 2 or more type.

The content of the other resin in the resin composition of the present invention is not particularly limited, but it is preferably 250 parts by weight or less, more preferably 100 parts by weight or less, and still more preferably 50 parts by weight with respect to 100 parts by weight of P3HA. Below, it is particularly preferably 20 parts by weight or less. The lower limit of the content of the other resin is not particularly limited, and may be 0 parts by weight.

[Ester compound]
The ester compound that may be contained in the resin composition of the present invention is a compound having an ester bond in its molecule (excluding P3HA and other resins described above). Specific examples of ester compounds include modified glycerin compounds, dibasic acid ester compounds, adipate compounds, polyether ester compounds, benzoic acid ester compounds, citrate compounds, isosorbide esters. and polycaprolactone-based compounds. Among them, glycerin ester-based compounds, dibasic acid ester-based compounds, adipate-based compounds, polyether ester-based compounds, or isosorbide ester-based compounds are preferred. Moreover, an ester compound can also be used individually by 1 type, and can also be used in combination of 2 or more type. When two or more kinds are used in combination, the mixing ratio of these ester compounds can be appropriately adjusted.

The resin composition of the present invention may contain no ester compound. Ester compounds having no double bond are preferred. When an ester compound having a radically reactive functional group is used, the progress of cross-linking in the resin composition is accelerated more than necessary, which may make it difficult to control the melt viscosity and melt tension. In this case, melt viscosity and melt tension become too large, and extrusion blow molding cannot be stably carried out in many cases. In the present invention, by using an ester compound that does not have a radically reactive functional group or by not blending an ester compound, the range of blending and temperature control is widened, and it is possible to select processing conditions that enable stable extrusion blow molding. The wider width leads to process simplification.

As the modified glycerin compound, a glycerin ester compound is preferred. As the glycerin ester-based compound, any of glycerin monoesters, diesters, and triesters can be used, but from the viewpoint of compatibility with PHA, glycerin triesters are preferred. Among glycerin triesters, glycerin diacetomonoester is particularly preferred. Specific examples of the glycerin diacetomonoester include glycerin diacetomonolaurate, glycerin diacetomonooleate, glycerin diacetomonostearate, glycerin diacetomonocaprylate, glycerin diacetomonodecanoate, and the like. Examples of the modified glycerin-based compound include "Rikemar" (registered trademark) PL series manufactured by Riken Vitamin Co., Ltd., and the like.

Dibasic acid ester compounds include dibutyl adipate, diisobutyl adipate, bis(2-ethylhexyl) adipate, diisononyl adipate, diisodecyl adipate, bis[2-(2-butoxyethoxy)ethyl]adipate, bis[2-(2- Butoxyethoxy)ethyl]adipate, bis(2-ethylhexyl)azelate, dibutyl sebacate, bis(2-ethylhexyl)sebacate, diethylsuccinate, mixed group dibasic acid ester compounds and the like.

Examples of adipate compounds include diethylhexyl adipate, dioctyl adipate, and diisononyl adipate.

Polyether ester compounds include polyethylene glycol dibenzoate, polyethylene glycol dicaprylate, polyethylene glycol diisostearate, and the like.

As the ester compound, modified glycerin-based compounds are preferable because they are excellent in cost and versatility and have a high degree of biomass, and glycerin triester is more preferable, especially in terms of compatibility with P3HA. Cetomonoester is more preferred, and glycerin diacetomonolaurate is particularly preferred.

The upper limit of the amount of the ester compound compounded in the resin composition of the present invention is 5 parts by weight or less, preferably 4 parts by weight or less, and particularly preferably 3 parts by weight or less, relative to 100 parts by weight of P3HA. If the content exceeds 5 parts by weight, the drawdown time of the resin composition may be shortened, and the molding conditions for extrusion blow molding may be narrowed.

The lower limit of the content of the ester compound in the resin composition of the present invention is not particularly limited, and may be 0 parts by weight. In the present invention, by not blending an ester compound, the moldable range of extrusion blow molding is increased, the selection range of the resin temperature applicable during extrusion blow molding, and the weight of the bottle container that can be manufactured by extrusion blow molding You can have a wider range of choices. On the other hand, when an ester compound is added to the resin composition of the present invention, the lower limit of the content is preferably 0.1 parts by weight or more, more preferably 0.5 parts by weight or more, and further preferably 1 part by weight or more. preferable. In the present invention, by blending an ester compound, it is possible to improve the impact resistance of the produced bottle container, particularly the impact resistance at low temperatures.

[Other ingredients]
The resin composition of the present invention may contain other components. For example, it may contain an organic or inorganic filler or the like within a range that does not impair the effects of the present invention. Among them, from the viewpoint of biodegradability and carbon neutrality of the obtained bottle container, for example, wood materials such as wood chips, wood flour, sawdust, rice husks, rice flour, starch, corn starch, rice straw, wheat straw, natural rubber, etc. Materials of natural origin are preferred. The content of the organic or inorganic filler can be set as appropriate and is not particularly limited. The organic or inorganic fillers can be used singly or in combination of two or more.

In addition to the above-mentioned organic or inorganic fillers, coloring agents such as pigments and dyes used as ordinary additives, odor absorbers such as activated carbon and zeolite, as long as the effects of the present invention are not impaired. Flavors such as vanillin and dextrin, antioxidants, antioxidants, weather resistance improvers, UV absorbers, lubricants, release agents, water repellents, antibacterial agents, sliding improvers, and other secondary additives It may contain one or two or more of The content of the additive can also be set as appropriate.

Here, the "crystal nucleating agent" and "lubricant" as components of the resin composition of the present invention will be described in more detail. The lubricant will be described more specifically as an "external lubricant".

[Crystal nucleating agent]
The resin composition of the present invention may also contain a crystal nucleating agent. As the crystal nucleating agent, for example, fatty acid amides and polyhydric alcohols are preferably used. Examples of fatty acid amides include behenic acid amides, and examples of polyhydric alcohols include pentaerythritol, galactitol, mannitol, and the like. A crystal nucleating agent can be used individually by 1 type, and can also be used in combination of 2 or more types. The content of the crystal nucleating agent can be set as appropriate and is not particularly limited.

[External lubricant]
The resin composition of the present invention may also contain an external lubricant. Examples of lubricants include erucamide, palmitic acid amide, oleic acid amide, stearic acid amide, methylenebisstearic acid amide, ethylenebisstearic acid amide, ethylenebisoleic acid amide, and ethylenebiserucic acid amide. . An external lubricant can be used individually by 1 type, and can also be used in combination of 2 or more types. The content of the lubricating agent can be set appropriately and is not particularly limited.

For example, when the resin composition of the present invention is produced by the below-described production method using an organic peroxide, a component derived from the organic peroxide (e.g., a decomposition product of the organic peroxide, a decomposition product derived from the compound, etc.). A description of the organic peroxide will be given later.

In the resin composition of the present invention, the ratio of the apparent melt viscosity (Pa s) to the drawdown time (sec) described later (sometimes referred to as "drawdown time/melt viscosity ratio") is 2.0 × 10 ⁻² (sec/[Pa·s]) or more and 8.0×10 ⁻² (sec/[Pa·s]) or less. The drawdown time/melt viscosity ratio of the resin composition of the present invention has an upper limit of 8.0×10 ⁻² (sec/[Pa s]) or less, and 6.0×10 ⁻² (sec/[Pa ·s]) or less, and particularly preferably 5.0×10 ⁻² (sec/[Pa·s]) or less. The lower limit is 2.0×10 ⁻² (sec/[Pa·s]) or more, preferably 3.0×10 ⁻² (sec/[Pa·s]) or more, and 3.5×10 ⁻² ( sec/[Pa·s]) or more is particularly preferable. The fact that the drawdown time/melt viscosity ratio of the resin composition of the present invention is controlled within the above range means that the melt viscosity and melt tension of the resin composition have an appropriate balance, particularly in extrusion blow molding. As a result, extrusion blow molding enables stable production of bottle containers under practical processing conditions, expanding the selection range of temperature conditions that can be applied during extrusion blow molding and the selection range of the weight of bottle containers that can be manufactured. As a result, it becomes possible to manufacture bottle containers of various weights at high speed.

In order for the resin composition containing poly(3-hydroxyalkanoate) to have the drawdown time/melt viscosity ratio as described above, the poly(3-hydroxyalkanoate) is uniformly and appropriately It is preferably a crosslinked poly(3-hydroxyalkanoate). The poly(3-hydroxyalkanoate) is, for example, an uncrosslinked (straight-chain) poly(3-hydroxyalkanoate) melted with an organic peroxide and, if necessary, an ester compound, as described later. It can be obtained by a kneading method or the like.

On the other hand, when the poly(3-hydroxyalkanoate) is excessively crosslinked, the rate of increase in melt tension with respect to the accompanying increase in melt viscosity becomes too large, and the drawdown time of the resin composition/ The melt viscosity ratio becomes too large and exceeds 8.0×10 ⁻² (sec/[Pa·s]), making it difficult to stably carry out extrusion blow molding. On the other hand, when the degree of cross-linking is too small, or when there is no branched structure due to cross-linking but the melt viscosity is high due to the high molecular weight, the drawdown time/melt viscosity ratio becomes too small, 2.0×10 ^{−2 .} It becomes less than (sec/[Pa·s]), making it difficult to stably carry out extrusion blow molding.

The melt viscosity (apparent melt viscosity) in the drawdown time/melt viscosity ratio of the resin composition of the present invention is defined as follows.
Melt viscosity: Using a capillary rheometer, a barrel setting temperature of 170 ° C., a diameter (d) of 0.05 cm connected to the tip of a barrel with a radius (D) of 0.4775 cm, from an orifice with a capillary length (l) of 1 cm, The load (F) when extruding the molten resin composition at a volumetric flow rate (Q) of 0.716 cm ³ /min and a shear rate of 122 sec ⁻¹ was measured, and the apparent melt viscosity ( η).

The melt viscosity of the resin composition of the present invention is not particularly limited, but the upper limit is preferably 2000 (Pa s) or less, more preferably 1900 (Pa s) or less, and particularly preferably 1800 (Pa s) or less. . The lower limit is preferably 1000 (Pa·s) or more, more preferably 1100 (Pa·s) or more, and particularly preferably 1200 (Pa·s) or more. By setting the melt viscosity to 1000 (Pa s) or more, drawdown of the parison during extrusion blow molding can be suppressed, and stable production can be achieved in single-head type production using one mold. tend to be able to On the other hand, by setting the melt viscosity to 2000 (Pa·s) or less, there is a tendency that deformation during cutting of the parison during extrusion blow molding can be suppressed, and uneven thickness can be suppressed. Incidentally, the melt viscosity of the resin composition of the present invention, for example, when the resin composition of the present invention is produced by the method described later, the amount of organic peroxide added, the amount of ester compound added, and the amount of P3HA It can be preferably controlled within the above range depending on the molecular weight and the like.

The drawdown time in the drawdown time/melt viscosity ratio of the resin composition of the present invention is defined as follows.
Drawdown time: The time required for the resin composition discharged from the orifice to drop 20 cm when measuring the melt viscosity.

The drawdown time of the resin composition of the present invention is not particularly limited, but the upper limit is preferably 80 (sec) or less, more preferably 75 (sec) or less, and particularly preferably 70 (sec) or less. The lower limit is preferably 15 (sec) or more, more preferably 20 (sec) or more, and particularly preferably 25 (sec) or more. By setting the drawdown time to 15 (sec) or longer, the resin tends to spread evenly in the step of blowing air during extrusion blow molding, thereby suppressing perforation. On the other hand, by setting the drawdown time to 80 (sec) or less, there is a tendency to suppress the excessive generation of gel and the resulting perforation during extrusion blow molding. The drawdown time of the resin composition of the present invention is, for example, when the resin composition of the present invention is produced by the method described later, the amount of organic peroxide added, the amount of ester compound added, and the amount of P3HA can be preferably controlled within the above range depending on the molecular weight of

The resin composition of the present invention has a wide selection range of temperature conditions applicable during extrusion blow molding and/or a wide selection range of weights of bottle containers that can be manufactured. , the moldable region is used in this application. The moldable region is produced by extrusion blow molding of a resin composition under a temperature condition where the die setting temperature of the extruder is 150 ° C. or higher, and a weight of 50 g or less in which unintended thin portions and holes are not visible in the bottle container. It shows the range of possible die set temperatures and bottle container weights. More specifically, the moldable region can be calculated by the method described in the section of Examples described later. In the present invention, the moldable region is preferably as large as possible, preferably 100 (° C.·g) or more, more preferably 200 (° C./g) or more, and particularly preferably 300 (° C./g) or more. The larger the moldable region, the wider the range of temperature conditions and container weights that can be selected. As a result, it is possible to manufacture bottle containers with a high yield even under conditions where the resin temperature tends to be high (for example, under conditions where the molding cycle time is short and the production is carried out at high speed). In addition, even a light weight bottle container that is inherently susceptible to forming thin-walled portions and holes can be manufactured with a high yield.

<Method for producing resin composition>
The method for producing the resin composition of the present invention is not particularly limited. It can be manufactured by a method including at least a step of melt-kneading (“melt-kneading step”) in an extruder at least 0.8 parts by weight and at most 0.8 parts by weight. According to the method, the drawdown time/melt viscosity ratio is controlled to 2.0 × 10 ^-2 (sec/[Pa s]) or more and 8.0 × 10 ^-2 (sec/[Pa s]) or less It is possible to obtain a resin composition having a That is, the resin composition of the present invention contains 100 parts by weight of poly(3-hydroxyalkanoate), 0.01 parts by weight or more and 0.8 parts by weight or less of an organic peroxide, and 0 parts by weight or more and 5 parts by weight of an ester compound. It may be obtained by melt-kneading the following in an extruder.

[Organic peroxide]
Examples of organic peroxides used in the melt-kneading step include diisobutyl peroxide, cumyl peroxyneodecanoate, di-n-propylperoxydicarbonate, diisopropylperoxydicarbonate, di-sec-butylperoxide, oxydicarbonate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, bis(4-t-butylcyclohexyl)peroxydicarbonate, bis(2-ethylhexyl)peroxydicarbonate, t-hexyl peroxyneodecanoate, t-butyl peroxyneodecanoate, t-butyl peroxyneoheptanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, di(3,5,5 -trimethylhexanoyl)peroxide, dilauroyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, disuccinic acid peroxide, 2,5-dimethyl-2,5- bis(2-ethylhexanoylperoxy)hexane, t-hexylperoxy-2-ethylhexanoate, di(4-methylbenzoyl)peroxide, dibenzoylperoxide, t-butylperoxy 2-ethylhexyl carbonate, t-butylperoxyisopropyl carbonate, 1,6-bis(t-butylperoxycarbonyloxy)hexane, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxyacetate, t -butyl peroxybenzoate, t-amyl peroxy, 3,5,5-trimethylhexanoate, 2,2-bis(4,4-di-t-butylperoxycyclohexy)propane, 2,2-di -t-butylperoxybutane and the like. Among them, t-butylperoxy-2-ethylhexyl carbonate and t-butylperoxyisopropyl carbonate are preferred. A combination of two or more of these organic peroxides can also be used.

Organic peroxides are used in various forms such as solid and liquid forms, and may be liquid forms diluted with a diluent or the like. Among them, when an ester compound is blended, an organic peroxide in a form that can be mixed with the ester compound (in particular, an organic peroxide that is liquid at room temperature (25 ° C.)) is dispersed more uniformly in P3HA. It is preferable because it becomes easy to suppress the local modification reaction in the resin composition, and it becomes easy to adjust the drawdown time/melt viscosity ratio.

From the viewpoint of enhancing the dispersibility in P3HA, the ester compound is also preferably a liquid ester compound at room temperature (25°C). As the ester compound which is liquid at room temperature, for example, an ester compound having a melting point of 20° C. or less is preferable.

Methods of obtaining P3HA compositions using organic peroxides are disclosed, for example, in US Pat. No. 9,034,989. However, in the patent, P3HA is branched using two or more cross-linking agents having two or more radical reactive functional groups (for example, epoxy groups or carbon-carbon double bonds) together with an organic peroxide. A featured technique is disclosed. For the compositions specifically disclosed in the patent, the ratio of melt viscosity to drawdown time as defined herein is estimated to be greater than 8.0×10 ⁻² (sec/[Pa·s]). . Furthermore, processing temperatures below the thermal decomposition temperature of P3HA leave unreacted peroxides in the composition, and when such compositions are subjected to extrusion blow molding, the remaining peroxides react. It is presumed that it will be difficult to manufacture a bottle container that is particularly light in weight because it causes local gelation and many pimples are generated.

The upper limit of the amount of the organic peroxide compounded in the melt-kneading step is 0.8 parts by weight or less, preferably 0.6 parts by weight or less, and particularly preferably 0.35 parts by weight or less. The lower limit is 0.01 parts by weight or more, preferably 0.05 parts by weight or more, and particularly preferably 0.1 parts by weight or more. 8. by controlling the amount of the organic peroxide to be used within the above range, the drawdown time/melt viscosity ratio of the obtained resin composition is 2.0×10 ⁻² (sec/[Pa·s]) or more; It is possible to control to 0×10 ⁻² (sec/[Pa·s]) or less.

The poly(3-hydroxyalkanoate) used in the melt-kneading step may be the same as those described above, but it is preferable to use poly(3-hydroxyalkanoate) that has not undergone cross-linking treatment. Specifically, the poly(3-hydroxyalkanoate) has a drawdown time/melt viscosity ratio of 1.0 × 10 ^-2 (sec/[Pa s]) or more and 2.0 × 10 ^-2 (sec/[Pa·s]) or less. A poly(3-hydroxyalkanoate) having such a drawdown time/melt viscosity ratio or a composition thereof itself has extremely poor extrusion blow moldability (see, for example, Comparative Example 1). Further, the poly(3-hydroxyalkanoate) has a melt viscosity of 900 (Pa s) or more and 1400 (Pa s) or less, and a drawdown time of 10 (sec) or more and 30 ( sec) the following.

The amount of the poly(3-hydroxyalkanoate) used in the melt-kneading step can be appropriately set according to the content in the resin composition.

As the ester compound used in the melt-kneading step, the same ester compound as described above can be used, and the amount thereof can be appropriately set according to the above content.

In the melt-kneading step, at least P3HA and an organic peroxide are put into an extruder and melt-kneaded. Other components, such as system fillers, may be put together into an extruder and melt-kneaded. However, in the present invention, it is preferable to perform melt-kneading without adding a cross-linking agent having two or more radical reactive functional groups (eg, epoxy groups or carbon-carbon double bonds).

In the melt-kneading step, the P3HA, the organic peroxide, and, if necessary, the ester compound may be individually charged into the extruder, or each component may be mixed and then charged into the extruder. . In particular, it is preferable to feed a mixture obtained by mixing an organic peroxide with an ester compound and P3HA, respectively, into an extruder. According to such a charging method, the dispersibility of the organic peroxide is improved, so that the resulting molded article is less likely to have lumps, and the drawdown time/melt viscosity ratio can be easily adjusted.

Melt-kneading in the melt-kneading step can be performed according to a known or commonly used method, and can be performed using, for example, an extruder (single-screw extruder, twin-screw extruder), a kneader, or the like. The conditions for melt-kneading are not particularly limited and can be set as appropriate, but it is preferable to set the resin temperature and residence time at which the reaction of the organic peroxide can be completed during melt-kneading. Specifically, the upper limit of the resin temperature measured with a die thermometer is preferably 190°C or lower, more preferably 180°C or lower, particularly preferably 170°C or lower, and the lower limit is preferably 120°C or higher, and 125°C or higher. More preferably, 130° C. or higher is particularly preferred. Further, the upper limit of the residence time in the extruder is preferably 700 seconds or less, more preferably 500 seconds or less, particularly preferably 300 seconds or less, and the lower limit is preferably 40 seconds or more, more preferably 50 seconds or more, and 60 seconds or more. Especially preferred.

The resin temperature and residence time are affected by the set temperature of the extruder, the screw rotation speed, and the screw configuration. It is preferable to provide a barrel zone in which the barrel set temperature of the extruder is 150° C. or higher and 180° C. or lower in at least half of the extruder, and set the screw rotation speed to 80 rpm or higher and 200 rpm or lower so that the time is 60 seconds or longer. . On the other hand, if the resin temperature exceeds 180 ° C., the deterioration of poly(3-hydroxyalkanoate) may be accelerated. It is preferable to set the barrel zone where the barrel setting temperature is 120° C. or more and 150° C. or less in half or less of the extruder. In order to facilitate pelletization of the resin discharged from the die (for example, pelletization by strand cutting, underwater cutting, etc.), the die setting temperature is, for example, 120 ° C. or higher and 150 ° C. or lower. Also, it is preferable to reduce mutual adhesion of pellets.

The resin composition of the present invention is obtained by melt-kneading, and is further molded (molded) to obtain various molded articles (molded articles formed by molding the resin composition of the present invention). be able to. In the present invention, a non-foamed molded article can be obtained particularly favorably. The molding method and molded article are not particularly limited, but since the resin composition of the present invention can be suitably used for extrusion blow molding, a bottle container manufactured by extrusion blow molding can be preferably exemplified. . Although the thickness of the side wall of such a bottle container is not particularly limited, it can be appropriately selected from a range of, for example, 0.1 mm or more and 5.0 mm or less. Examples of other formed bodies include films and sheets produced by inflation molding, and containers formed by vacuum molding.

In the extrusion blow molding, a molten resin is extruded into a tube shape (parison) from an extruder with an annular die attached to the tip, and the parison in a molten state is sandwiched from both sides by a mold to pinch off the lower part of the parison and melt it. In this method, air is blown into the inside of a parison closed at one end to mold it into a bottle shape, and after cooling, the mold is opened to take out the molded product. The extrusion blow molding method is not particularly limited, but can be carried out, for example, using a general extrusion blow molding machine used for extrusion blow molding of thermoplastic resins. A typical extrusion blow molding machine is a single screw extruder fitted with an annular die. The above-mentioned single-screw extruder melt-kneads the charged raw material resin and obtains a constant discharge while maintaining a desired temperature.

The molding temperature in the extrusion blow molding is not particularly limited as long as it is a temperature at which the resin can be appropriately melted, but for example, 135° C. or higher and 180° C. or lower is preferable. The term "molding temperature" as used herein refers to the temperature of the resin between the time it is put into the extruder and the time it is discharged from the die. The resin temperature can generally be measured, for example, with a thermometer installed on the adapter.

The molding cycle time in extrusion blow molding is determined by the drawdown time, the resin discharge amount, and the air blowing time, but can be adjusted within a range in which the extrusion blow moldability can be maintained. In general, 10 (sec) or more and 50 (sec) or less are preferable.

In general, the molding cycle can be shortened by increasing the resin discharge rate, but this tends to increase the shear heat generation when passing through the screw and die, and the resin temperature tends to rise. At this time, the drawdown time/melt viscosity ratio of the non-crosslinked poly(3-hydroxyalkanoate) falls below 2.0×10 ⁻² (sec/[Pa·s]), making extrusion blow molding difficult. Become. However, according to the present invention, a crosslinked poly(3-hydroxyalkanoate) is used to increase the drawdown time/melt viscosity ratio of the resin composition to 2.0×10 ⁻² (sec/[Pa·s]) or more. By doing so, extrusion blow molding becomes possible even when the resin temperature is high. Therefore, the present invention has the advantage that a short molding cycle can be adopted and high-speed mass production can be realized.

The temperature of the mold in extrusion blow molding is not particularly limited, but is preferably 20° C. or higher and 50° C. or lower in order to facilitate solidification of poly(3-hydroxyalkanoate).

In the present invention, a bottle container is a hollow container having at least a substantially circular or polygonal bottom wall, an upright side wall connected to the bottom wall, an opening at the top, and optionally a top wall. It is usually used to store liquids and solids inside, and the contents can be put in and taken out through the opening. The thickness of the side wall of the bottle container of the present invention is usually 0.1 mm or more and 5.0 mm or less, preferably 0.3 mm or more and 2.0 mm or less, from the viewpoint of the balance between impact resistance and portability. .

It is preferable that the bottle container of the present invention is formed so that the thickness of the sidewall is highly uniform from the viewpoint of ensuring impact resistance while being made of poly(3-hydroxyalkanoate). Specifically, it is preferable that the ratio of the minimum thickness to the maximum thickness of the side wall of the bottle container of the present invention is 0.7 or more. By making the thickness of the side wall uniform in this way, the bottle container is less likely to break even if it receives an impact when dropped.

In the present invention, when determining the thickness of the side wall of the bottle container and the ratio of the minimum thickness to the maximum thickness of the side wall, the thickness of the bottom wall and the top wall of the bottle container and the wall constituting the opening of the bottle container The thickness of the part is not considered. Also, the thickness of the corner connecting the side wall and the bottom wall, the top wall, or the opening, and the thickness of the corner of the irregularities provided on the side wall are not taken into consideration. Furthermore, among the side walls, the thickness of the side wall formed thicker than the other side walls for the purpose of improving the ease of holding the bottle container by hand, designability, productivity, etc. is not taken into consideration.

The height of the bottle container of the present invention is not particularly limited, but is preferably 50 cm or less, more preferably 40 cm or less, and even more preferably 30 cm or less from the viewpoint of portability.

Since the weight of the bottle container that can be manufactured according to the present invention is widened, the weight of the bottle container of the present invention is not particularly limited. 75 g or more and 25 g or less are more preferable.

In extrusion blow molding, the parison can be thinned by reducing the resin discharge amount or narrowing the die gap, and a light bottle container can be produced. However, if the drawdown time/melt viscosity ratio is low, holes will form from thin areas and lumps when air is blown in. In the present invention, a lightweight bottle container is produced by extrusion blow molding by setting the drawdown time/melt viscosity ratio of the resin composition to 2.0×10 ⁻² (sec/[Pa·s]) or more. It is possible to suppress the formation of thin portions and holes.

The molding method in extrusion blow molding is not particularly limited, and a bottle container can be produced by a single-headed type, a double-headed type, a multi-headed type, a mold sliding type, or the like. Conventionally, however, when the discharge rate of an extrusion blow molding machine is increased for mass production, the resin temperature rises due to shear heat generation, which tends to make extrusion blow molding difficult. In the present invention, by setting the drawdown time/melt viscosity ratio of the resin composition to 2.0×10 ⁻² (sec/[Pa·s]) or more, the discharge rate of the extrusion blow molding machine is increased to increase the resin temperature. A bottle container can be manufactured suitably even if it rises.

EXAMPLES The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

In the examples, the following raw materials were used.
(P3HA)
A-1: A 3-hydroxyhexanoate (3HH) composition of 11.2 mol% obtained according to the method described in International Publication No. 2013/147139, and a weight average molecular weight in terms of standard polystyrene measured by GPC. 580,000 poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P3HB3HH)
A-2: P3HB3HH having a 3HH composition of 5.4 mol% and a weight average molecular weight of 620,000 in terms of standard polystyrene measured by GPC, obtained according to the method described in WO 2008/010296.
A-3: Ecomann EM5400F [poly (3-hydroxybutyrate-co-4-hydroxybutyrate) (P3HB4HB)]

(organic peroxide)
B-1: Perbutyl I manufactured by NOF Corporation (t-butyl peroxyisopropyl carbonate, 1 minute half-life temperature: 159 ° C.)
B-2: Trigonox 117 manufactured by Kayaku Akzo Co., Ltd. (tert-butylperoxy 2-ethylhexyl carbonate, 1 minute half-life temperature: 156° C.)

(Ester compound)
C-1: Rikemal PL-012 (glycerin diacetomonolaurate) manufactured by Riken Vitamin Co., Ltd.
C-2: Daihachi Chemical Co., Ltd. DAIFATTY101 (mixed radical dibasic acid ester)

The following evaluations were carried out for each example and comparative example.

[Melt viscosity]
Using a capillary rheometer manufactured by Shimadzu Corporation, from an orifice with a radius (d) of 0.05 cm and a capillary length (l) of 1 cm connected to the tip of a barrel with a barrel setting temperature of 170 ° C. and a radius (D) of 0.4775 cm The melted resin composition was extruded at a volumetric flow rate (Q) of 0.716 cm ³ /min and a shear rate of 122 sec ^-1 to measure the load (F). Apparent melt viscosity (η) was calculated from the following formula (1).

[Drawdown time]
When the melt viscosity was measured, the time required for the molten resin discharged from the orifice to fall by 20 cm was measured, and this was taken as the drawdown time (DT).

[Moldable area]
As an index that quantitatively indicates the range of processing conditions (temperature during molding and weight of bottle container) that can be selected when manufacturing bottle containers by extrusion blow molding, the "moldable range" is determined by the following method. Calculated. The larger the "moldable range", the wider the selection of processing conditions, and it is an index of moldability at an industrial level where fine adjustment of processing conditions is generally difficult. In this evaluation, a hollow molding machine (manufactured by Japan Steel Works, Ltd.) was used in which an annular die with a die inner diameter of 25φ and a core inner diameter of 22φ was connected to an extruder having a single screw of L/D=22.

(1) First, a bottle container was produced by extrusion blow molding of a resin composition under the initial conditions of an extruder die set temperature of 150° C. and a screw rotation speed of 16 rpm. The die gap is set to 1.5 mm, and the bottle container is manufactured by extruding downward from an annular die into a tubular shape (parison), sandwiching the parison from both sides with a mold located 20 cm below the die to obtain a parison. Pinch off and fuse the lower part of the parison, blow air into the parison closed at one end, and cool and solidify the parison. It was carried out by making a bottle container of Thereafter, the screw rotation speed was lowered, and the weight of the container was lowered stepwise by 5 g to prepare a bottle container. The production of this bottle container was continued until the appearance of the bottle was found to be poor (“x” evaluation) in the evaluation of the moldability of the bottle container described below. As a result, the weight range of the bottle container that can be extrusion blow-molded at the die setting temperature of 150° C. was confirmed.

(Evaluation of bottle container formability)
◯: The appearance of the obtained bottle was visually observed, and no extremely thin portion or hole was found in the container.
x: A state in which extremely thin portions and holes are found in the container by visually inspecting the appearance of the obtained bottle.

(2) Next, the die set temperature is increased by 3°C, the screw rotation speed is set to 16 rpm, and extrusion blow molding is performed in the same manner as in (1) above to produce a bottle container having a container weight of 50 g. As in the case, the screw speed was lowered and the weight of the container was lowered stepwise by 5 g to prepare a bottle container, and the range of weight of the bottle container that can be extrusion blow molded at the die setting temperature was confirmed.

(3) Furthermore, even under the conditions of a screw rotation speed of 16 rpm and a container weight of 50 g, the die set temperature was increased stepwise by 3 ° C. until the bottle container moldability was evaluated as "x" in the bottle container moldability evaluation. The operation of (2) was repeated.

Regarding the results of bottle container moldability evaluation (“○” or “×” evaluation) under the conditions of the die setting temperature of 150 ° C. or higher and the bottle container weight of 50 g or less confirmed in the above work, the horizontal axis as shown in FIG. It is shown in a graph with set temperature (°C) and container weight (g) on the vertical axis. In the graph, the widest area formed by connecting circles was calculated as the above-mentioned "moldable region" (°C·g) and shown in Table 1. FIG. 1 shows an example of a moldable region in the case of the first embodiment. Specifically, referring to FIG. 1, when the die set temperature is 150° C., 153° C., 156° C., 159° C., or 162° C., the moldability of a bottle container weighing 50 g or 45 g is evaluated as “○”. It was evaluated as "x" with a weight of 40 g. When the die setting temperature was 165° C. or 168° C., the moldability of bottle containers with a weight of 50 g, 45 g or 40 g was evaluated as “◯”, and the moldability with a weight of 35 g was evaluated as “×”. When the die setting temperature was 171° C., the moldability of bottle containers with a weight of 50 g, 45 g, 40 g, or 35 g was evaluated as “◯”, and the weight of 30 g was evaluated as “×”. When the die setting temperature was 174° C., the moldability of a bottle container weighing 50 g was evaluated as “×”. From the above, the moldable region was calculated as 15° C.×10 g+6° C.×15 g+3° C.×20 g=300 (° C.g).

[Impact resistance evaluation of bottle container]
380 ml of water was placed in a 50 g bottle container, covered, stored for 24 hours, and dropped from a height of 1 m. The evaluation was performed in an evaluation test room set at 25°C and an evaluation test room set at 4°C.

Example 1
(Method for producing resin composition)
P3HA (A-1), organic peroxide (B-1), and ester compound (C-1) are dry blended at the compounding ratio shown in Table 1, and co-meshing twin-screw extruder (manufactured by Toshiba Machine Co., Ltd.: Using a TEM26ss), melt-kneading was performed at a set temperature of 120° C. or higher and 170° C. or lower at a screw rotation speed of 100 rpm, and strand cutting was performed to obtain a resin composition. Table 1 shows the resin temperature measured by the die thermometer. In addition, Table 1 shows the residence time, which is the time from the introduction of each material into the extruder until the resin composition emerges from the die.

Table 1 shows the melt viscosity (η), drawdown time (DT), and DT/η of the obtained resin composition.

(bottle container molding)
Using the obtained resin composition, a bottle container was molded by the method described in "Moldable range" above, and the moldable range was evaluated. Table 1 shows the evaluation results.

The obtained bottle container was evaluated for impact resistance. Table 1 shows the test results.

Examples 2-6
A resin composition was produced in the same manner as in Example 1 except that the amount of peroxide blended or the type of peroxide was changed as shown in Table 1, and the melt viscosity (η) and drawdown time (DT ), DT/η, resin temperature, and residence time were evaluated. Further, a bottle container was molded in the same manner as in Example 1, the moldable region was evaluated, and the impact resistance of the obtained bottle container was also evaluated. Table 1 shows the evaluation results.

Comparative example 1
A resin composition was produced in the same manner as in Example 1 except that the amount of the organic peroxide was changed as shown in Table 1, and the melt viscosity (η), drawdown time (DT), DT/η , resin temperature and residence time were evaluated. Further, a bottle container was molded in the same manner as in Example 1, the moldable region was evaluated, and the impact resistance of the obtained bottle container was also evaluated. Table 1 shows the evaluation results.

Examples 7-10
A resin composition was produced in the same manner as in Example 1 except that the type of ester compound or the amount thereof was changed as shown in Table 2, and the melt viscosity (η), drawdown time (DT), DT/η , resin temperature and residence time were evaluated. Further, a bottle container was molded in the same manner as in Example 1, the moldable region was evaluated, and the impact resistance of the obtained bottle container was also evaluated. Table 2 shows the evaluation results.

Comparative Examples 2-5
A resin composition was produced in the same manner as in Example 1 except that the type or amount of the ester compound was changed as shown in Table 2, and the melt viscosity (η), drawdown time (DT), DT/η , resin temperature and residence time were evaluated. Further, a bottle container was molded in the same manner as in Example 1, the moldable region was evaluated, and the impact resistance of the obtained bottle container was also evaluated. Table 2 shows the evaluation results.

Examples 11-14
A resin composition was produced in the same manner as in Example 1 except that the type of P3HA or the amount of the ester compound was changed as shown in Table 3, and the melt viscosity (η), drawdown time (DT), DT /η, resin temperature, and residence time were evaluated. Further, a bottle container was molded in the same manner as in Example 1, the moldable region was evaluated, and the impact resistance of the obtained bottle container was also evaluated. Table 3 shows the evaluation results.

From Table 1, in Examples 1 to 6 in which the drawdown time/melt viscosity ratio of the resin composition was 2.0 × 10 ^-2 (sec/[Pa s]) or more, the drawdown time/melt viscosity ratio is less than 2.0×10 ⁻² (sec/[Pa s]), the moldable region is large, and the selection range of the resin temperature applicable during extrusion blow molding and / Alternatively, it can be seen that there is a wide selection of weights for bottle containers that can be manufactured by extrusion blow molding.

From Table 2, 5 parts by weight or less of the ester compound was added to the composition of Example 1, and the drawdown time/melt viscosity ratio of the resin composition was 2.0 × 10 ^-2 (sec/[Pa s]). In Examples 7 to 10 described above, Comparative Examples 2 to 5 in which more than 5 parts by weight of an ester compound was blended, and a drawdown time/melt viscosity ratio of 2.0 × 10 ^-2 (sec/[Pa s ]), it can be seen that the moldable region is large compared to Comparative Example 1, which was less than Furthermore, it can be seen that the bottle containers produced in Examples 7 to 10 are superior in impact resistance at low temperatures compared to the bottle container produced in Example 1.

From Table 3, although a different type of P3HA is used from Example 1, the drawdown time/melt viscosity ratio of the resin composition is 2.0 × 10 ^-2 (sec/[Pa s]) or more. It can be seen that Examples 11 to 14, which were present, also have a large moldable region.

Claims (13)

Contains 100 parts by weight of poly(3-hydroxyalkanoate) and 0 parts by weight or more and 5 parts by weight or less of an ester compound, and the following ratio of melt viscosity (Pa s) to drawdown time (sec) is 2.0 ×10 ^-2 (sec/[Pa s]) or more and 8.0 × 10 ^-2 (sec/[Pa s]) or less ,
The poly(3-hydroxyalkanoate) is crosslinked,
The ester compounds include glycerin ester compounds, dibasic ester compounds, adipate ester compounds, polyether ester compounds, benzoate ester compounds, citrate ester compounds, isosorbide ester compounds, and poly At least one selected from the group consisting of caprolactone compounds,
By extrusion blow molding, the moldable range indicating the range of the die setting temperature and the bottle container weight that can produce a bottle container weighing 50 g or less under the temperature condition of the die setting temperature of the extruder of 150 ° C. or higher is 200 (° C. g ) or more, the resin composition.
Melt viscosity: Using a capillary rheometer, a barrel setting temperature of 170 ° C., a diameter (d) of 0.05 cm connected to the tip of a barrel with a radius (D) of 0.4775 cm, from an orifice with a capillary length (l) of 1 cm, The load (F) when extruding the molten resin composition at a volumetric flow rate (Q) of 0.716 cm ³ /min and a shear rate of 122 sec ⁻¹ was measured, and the apparent melt viscosity ( η).
Drawdown time: The time required for the resin composition discharged from the orifice to drop 20 cm when measuring the melt viscosity.

The resin composition according to claim 1, wherein the melt viscosity is 1000 (Pa·s) or more and 2000 (Pa·s) or less. The resin composition according to claim 1 or 2, wherein the drawdown time is 15 (sec) or more and 80 (sec) or less. A melt-kneaded product of 100 parts by weight of poly(3-hydroxyalkanoate), 0 to 5 parts by weight of an ester compound, and 0.01 to 0.8 parts by weight of an organic peroxide. 4. The resin composition according to any one of 1 to 3. 5. The resin composition according to any one of claims 1 to 4 , wherein the ester compound is an ester compound having no radically reactive functional group. Poly (3-hydroxyalkanoate), poly (3-hydroxybutyrate-co-3-hydroxyvalerate), poly (3-hydroxybutyrate-co-3-hydroxyhexanoate), poly (3-hydroxy butyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate), poly(3-hydroxybutyrate-co-4-hydroxybutyrate), poly(3-hydroxybutyrate-co-3- The resin composition according to any one of claims 1 to 5 , which is at least one selected from the group consisting of hydroxyoctanoate) and poly(3-hydroxybutyrate-co-3-hydroxydecanoate). thing. The ester compound is at least one selected from the group consisting of glycerin ester compounds, dibasic acid ester compounds, adipate compounds, polyether ester compounds and isosorbide ester compounds. 7. The resin composition according to any one of 6 . The resin composition according to any one of claims 1 to 7 , for extrusion blow molding. A molded article obtained by molding the resin composition according to any one of claims 1 to 8 . The molded article according to claim 9 , which is a bottle container. A method for producing the resin composition according to any one of claims 1 to 8 ,
100 parts by weight of poly(3-hydroxyalkanoate), 0 parts by weight or more and 5 parts by weight or less of an ester compound and 0.01 parts by weight or more and 0.8 parts by weight or less of an organic peroxide are extruded to a resin temperature A manufacturing method comprising a step of melt-kneading in the range of 120 ° C. or higher and 190 ° C. or lower. 12. The production method according to claim 11 , wherein the melt-kneading is performed so that the mixture stays in the extruder for 40 seconds or more and 700 seconds or less. After melting the resin composition according to any one of claims 1 to 8 in an extruder, extruding into a tube shape from an annular die, sandwiching the tube from both sides with a mold, and one end A method for manufacturing a bottle container, comprising a step of blowing air into the closed tube to form a bottle shape.

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