JP2018009107A - Method for producing aliphatic polyester resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an aliphatic polyester resin composition that can stably secure good dispersibility of silica and can improve productivity of a resin composition, in obtaining a resin composition containing at least aliphatic polyester, silica, and a dispersion aid by melt-kneading.SOLUTION: In a method for producing an aliphatic polyester resin composition containing 5 to 23 pts.wt. of silica (B) and 8 to 23 pts.wt. of a dispersion aid (C) with respect to 100 pts.wt. of aliphatic polyester (A), the method includes a first step of mixing the silica (B) and the dispersion aid (C) with the aliphatic polyester (A), and a melt-kneading step of melt-kneading a mixture obtained in the first step, where the aliphatic polyester (A) mixed in the first step is particulate aliphatic polyester having an average particle size of 100 to 700 μm.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing an aliphatic polyester resin composition, and particularly a fat that can be suitably used for producing sheets and films having high tear strength and good appearance for application as various industrial materials. The present invention relates to a method for producing a group polyester resin composition.

  In recent years, plastic waste has become a problem that exerts a heavy load on the global environment, such as impact on the ecosystem, generation of harmful gases during combustion, global warming due to a large amount of heat of combustion, and so on. The development of biodegradable plastics has become active as possible.

  In particular, when the biodegradable plastic is derived from a plant, carbon dioxide produced when the biodegradable plastic is burned is originally in the air, and carbon dioxide in the atmosphere does not increase. This is called carbon neutral, and it is regarded as important under the Kyoto Protocol that imposes a target value for carbon dioxide reduction, and active use is desired.

  Recently, from the viewpoint of biodegradability and carbon neutral, aliphatic polyester-based resins have attracted attention as plant-derived plastics. In particular, polyhydroxyalkanoate (hereinafter sometimes referred to as PHA) -based resins, and also PHA-based resins. Among the resins, poly (3-hydroxybutyrate) homopolymer resin (hereinafter sometimes referred to as P3HB), poly (3-hydroxybutyrate-co-3-hydroxyvalerate) copolymer resin (hereinafter referred to as P3HB3HV). Poly (3-hydroxybutyrate-co-3-hydroxyhexanoate) copolymer resin (hereinafter sometimes referred to as P3HB3HH), poly (3-hydroxybutyrate-co-4-hydroxybutyrate). Rate) copolymer resin (hereinafter sometimes referred to as P3HB4HB) and poly Acid (hereinafter, sometimes referred to as PLA) or the like has attracted attention.

  However, films and sheets made of aliphatic polyester and a resin composition containing the same are actually inferior in tear strength and inferior in practical properties, and various studies have been conducted to improve the properties.

  Patent Document 1 discloses a polyester resin composition having improved tear strength with a formulation in which aliphatic polyester, polybutylene adipate terephthalate (PBAT), hydrophilic silica, and a plasticizer are blended. Production of the composition As a method, there is disclosed a production method including a first step of melt kneading an aliphatic polyester, hydrophilic silica and a plasticizer, and a second step of adding PBAT and melt kneading.

  Patent Document 2 discloses a technique for molding a resin composition containing an aliphatic polyester resin, an aromatic aliphatic polyester resin, and inorganic particles for the purpose of high tear strength and easy biodegradability. However, when the resin composition obtained by the technique is used for a film used for a shopping bag, a garbage bag, an agricultural material, or the like that is used by putting a heavy article or various shapes, for example, tear strength Is extremely low and is not very practical. In addition, for example, when inorganic particles having a small bulk density and easily secondary agglomeration are used, dispersion is possible even if processed by the method disclosed in Patent Document 2. There was a case where there was a problem with sex.

International Publication No. 2014/054278 JP 2009-221337 A

  By the way, according to the manufacturing method described in Patent Document 1, it is possible to obtain a resin composition that is excellent in transparency, moldability, and mechanical properties, and also excellent in biodegradability. However, as a result of continuous studies on the present method by the present inventors, it has been found that there is room for further improvement in the above method from the viewpoint of improving the dispersibility of silica and improving the tensile strength of the resin composition.

  The present invention is a process that can stably obtain good dispersibility of silica and improve the productivity of the resin composition when melt-kneading a resin composition containing at least an aliphatic polyester, silica, and a dispersion aid. It aims to provide a method.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor has stably mixed silica having a specific particle size with other specific raw materials at a specific blending amount before melt-kneading. The inventors have found a production method capable of ensuring dispersibility and improving the productivity of the resin composition, and have completed the present invention.

  That is, this invention provides the following invention, for example.

[1] A method for producing an aliphatic polyester resin composition containing 5 to 23 parts by weight of silica (B) and 8 to 23 parts by weight of a dispersion aid (C) with respect to 100 parts by weight of the aliphatic polyester (A). There,
A first step of mixing the aliphatic polyester (A) with the silica (B) and the dispersion aid (C);
A melt-kneading step of melt-kneading the mixture obtained in the first step,
The method for producing an aliphatic polyester resin composition, wherein the aliphatic polyester (A) to be mixed in the first step is a particulate aliphatic polyester having an average particle diameter of 100 to 700 μm.

  [2] The fat according to [1], wherein the first step is a step of mixing silica (B), a dispersion aid (C), and an aliphatic aromatic polyester (D) with the aliphatic polyester (A). For producing a polyester resin composition.

  [3] The method for producing an aliphatic polyester resin composition according to [1], including a step of melt-kneading the obtained kneaded product and the aliphatic aromatic polyester (D) after the melt-kneading step.

  [4] The aliphatic polyester resin according to any one of [1] to [3], wherein the aliphatic polyester (A) mixed in the first step is a particulate aliphatic polyester having an average particle size of 200 to 450 μm. A method for producing the composition.

  [5] Any one of [1] to [4], wherein the silica (B) to be mixed in the first step is silica having an adsorbed water amount volatilized at 160 ° C. of 0.5% by weight to 7% by weight. The manufacturing method of the aliphatic polyester resin composition of description.

  [6] The dispersion aid (C) is at least one selected from the group consisting of a glycerin ester compound, an adipic acid ester compound, a polyether ester compound and an isosorbide ester compound. 5] The manufacturing method of the aliphatic polyester resin composition as described in any one of.

  [7] The method for producing an aliphatic polyester resin composition according to any one of [1] to [6], wherein the aliphatic polyester resin composition is a molded body.

  According to the present invention, even when silica having a low particle size and bulk density is used, in the aliphatic polyester resin composition, an aliphatic aromatic polyester (for example, an aliphatic polyester resin that can be added in and / or further to the aliphatic polyester resin) Silica can be stably dispersed well in polybutylene adipate terephthalate (PBAT) or polybutylene succinate terephthalate (PBST), and low productivity due to the low feed property of silica is improved to provide a production method I can do it.

  Hereinafter, the present invention will be described in more detail.

  The method for producing an aliphatic polyester resin composition of the present invention comprises aliphatic polyester (A), silica (B), and dispersion aid (C) as essential components, and silica (B) as aliphatic. An aliphatic polyester resin composition containing 5 to 23 parts by weight per 100 parts by weight of polyester (A) and 8 to 23 parts by weight of a dispersion aid (C) per 100 parts by weight of aliphatic polyester (A) (“ This may be referred to as “the aliphatic polyester resin composition of the present invention”. The aliphatic polyester resin composition of the present invention may further contain other components such as an aliphatic aromatic polyester (D).

(Aliphatic polyester)
Examples of the aliphatic polyester (A) used in the present invention include polyhydroxyalkanoate (PHA) (microorganism-produced polyhydroxyalkanoate) produced from microorganisms and PLA.

In the present invention, PHA is an aliphatic polyester resin containing a repeating unit represented by the general formula: [—CHR—CH ₂ —CO—O—].

In particular, PHA is represented by the formula (1): [—CHR—CH ₂ —CO—O—] (wherein R is an alkyl group represented by C _n H _{2n + 1} , and n is an integer of 1 or more and 15 or less. It is preferable that it contains a repeating unit represented by:

  The microorganism that produces PHA is not particularly limited as long as it is a microorganism capable of producing PHAs. For example, as a bacteria producing poly (3-hydroxybutyrate) (hereinafter sometimes abbreviated as “PHB”), Bacillus megaterium discovered in 1925 is the first, and Capriavidus necator is also available. ) (Old classification: Alkaligenes eutrophus, Ralstonia eutropha), Alkaigenes latus (Alcaligenes latus) and other natural microorganisms are known, PHB is accumulated in the cells .

  Moreover, as a microbe producing a copolymer of hydroxybutyrate and other hydroxyalkanoate, poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (hereinafter abbreviated as “PHBV” may be used in some cases). ) And poly (3-hydroxybutyrate-co-3-hydroxyhexanoate (hereinafter sometimes abbreviated as “PHBH”) producing bacteria, Aeromonas caviae, poly (3-hydroxybutyrate) Alkaligenes eutrophus, which is a producer of (Rate-co-4-hydroxybutyrate), is known, etc. In particular, with regard to PHBH, in order to increase the productivity of PHBH, the genes of the PHA synthase group were introduced. Alkage Genes Eutrophas The strain AC32 (Alcaligenes eutrophus AC32, FERM BP-6038) (T. Fukui, Y. Doi, J. Bateriol., 179, p4821-2830 (1997)) is more preferable, and these microorganisms are cultured under appropriate conditions. In addition to the above, microbial cells with PHBH accumulated in the cells may be used.In addition to the above, genetically modified microorganisms introduced with various PHA synthesis-related genes may be used according to the PHA to be produced. Culture conditions including types may be optimized.

  The molecular weight of the PHA used in the present invention is not particularly limited as long as it exhibits substantially sufficient physical properties for the intended use. When the molecular weight is low, the strength of the obtained molded product is lowered. On the other hand, if it is high, the workability is lowered and molding becomes difficult. In consideration of these, the range of the weight average molecular weight of the PHA used in the present invention is preferably 50,000 to 3,000,000, more preferably 100,000 to 1,500,000.

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

  Examples of PHA that can be used in the present invention include PHB [poly (3-hydroxybutyrate), poly (3-hydroxybutyric acid)], PHBH [poly (3-hydroxybutyrate-co-3-hydroxyhexanoate). ), Poly (3-hydroxybutyric acid-co-3-hydroxyhexanoic acid)], PHBV [poly (3-hydroxybutyrate-co-3-hydroxyvalerate), poly (3-hydroxybutyric acid-co-3-hydroxy) Valeric acid)], P3HB3HV3HH [poly (3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate), poly (3-hydroxybutyric acid-co-3-hydroxyvaleric acid-co- 3-hydroxyhexanoic acid)], P3HB4HB [poly (3-hydroxybutyrate-co-4-hydroxybutyrate), Li (3-hydroxybutyrate-co-4-hydroxybutyrate)], poly (3-hydroxybutyrate-co-3-hydroxyoctanoate), poly (3-hydroxybutyrate-co-3-hydroxyoctadecano) E) and polylactic acid. Among these, PHB, PHBH, PHBV, P3HB3HV3HH, P3HB4HB, and polylactic acid are preferred because they are industrially easy to produce.

  The composition ratio of the repeating unit of PHA is preferably 80 to 99 mol%, and 85 to 97 mol in terms of the composition ratio of 3-hydroxybutyrate (3HB) from the viewpoint of balance between flexibility and strength. % Is more preferable. If the composition ratio of 3-hydroxybutyrate (3HB) is less than 80 mol%, the rigidity tends to be insufficient, and if it exceeds 99 mol%, the flexibility tends to be insufficient. In addition, each composition ratio which is a repeating unit in the copolymer resin of PHA can be measured by gas chromatography or the like (for example, see International Publication No. 2014/020838).

  In the present invention, mainly in order to improve the feed property of fine silica having a low bulk density and poor feed property, and in order to make the dispersion aid (C) function effectively in dispersing silica (B), The aliphatic polyester (A) mixed in the first step is a particulate (eg, powder) aliphatic polyester. The average particle diameter (cumulative 50% particle diameter in microtrack measurement) of the aliphatic polyester (A) mixed in the first step is 100 to 700 μm, preferably 200 μm or more, more preferably 280 μm or more, It is preferably 600 μm or less, more preferably 500 μm or less. When the average particle size is smaller than 100 μm, there is a problem that productivity is lowered due to poor feedability and handling property. On the other hand, when the average particle size is larger than 700 μm, the difference in particle size from silica (B) becomes large, so that it is not sufficiently mixed or classified, and aliphatic polyester (A) and silica (B) If the mixture is still bulky and the feedability is poor and there is a problem in productivity, or if the dispersion aid (C) is excessively adhered to the silica (B) locally, the silica (B) is agglomerated. There is a possibility.

  The content of the aliphatic polyester (A) in the aliphatic polyester resin composition of the present invention is preferably 10 to 90% by weight, more preferably 25 to 80% by weight with respect to the total amount (100% by weight) of the resin composition. %, More preferably 35 to 80% by weight. When the content is 10% by weight or more, it is possible to effectively develop biodegradability, or to suppress the tackiness that is a defect of the aliphatic aromatic polyester, and to form a film or the like. There is a tendency to ensure openness. On the other hand, when the content is 90% by weight or less, the influence of the low crystallization rate, which is a defect of the aliphatic polyester, is suppressed and the productivity tends to be improved. In the aliphatic polyester resin composition of the present invention, the aliphatic polyester (A) can be used alone or in combination of two or more.

(silica)
The type of silica (B) used in the present invention is not particularly limited, but synthetic amorphous silica produced by a dry method or a wet method is preferable from the viewpoint of versatility. Either hydrophobic treatment or non-hydrophobic treatment can be used, and one kind can be used alone, or two or more kinds can be used in combination.

  The blending amount (total blending amount) of silica (B) in the present invention is 5 to 23 parts by weight with respect to 100 parts by weight of the total amount of aliphatic polyester (A) blended in the present invention. When the amount is less than 5 parts by weight, sufficient mechanical properties such as tear strength are improved when compounded with aliphatic aromatic polyester (D) such as polybutylene adipate terephthalate (PBAT) or polybutylene succinate terephthalate (PBST). May not be expressed. Moreover, when more than 23 weight part, it may become difficult to disperse | distribute silica (B) favorably. The blending amount of silica (B) is preferably 6 parts by weight or more, more preferably 8 parts by weight or more, and preferably 20 parts by weight or less, more preferably 18 parts by weight or less, and further preferably 15 parts by weight or less. is there.

  As the silica (B) to be mixed in the first step in the present invention, silica having an adsorbed water amount of 0.5 wt% or more and 7 wt% or less is preferable. The amount of adsorbed moisture can be measured by using, for example, an electromagnetic balance MX-50 manufactured by Kensei Kogyo Co., Ltd., and the volatile content at 160 ° C. as the amount of adsorbed moisture. When the amount of adsorbed water is larger than 7% by weight, it is difficult to disperse due to the cohesive force of the water adsorbed between the silica (B) surface and the particles, and it may become a fish eye at the time of film formation and cause poor appearance. On the other hand, if it is less than 0.5% by weight, the water remaining slightly between the particles forms a cross-linked liquid film and produces a large binding force due to surface tension, which tends to make separation and dispersion extremely difficult.

  Moreover, the average primary particle diameter of the silica (B) used in the present invention can improve the tear strength of the film or sheet, hardly cause defects in appearance such as fish eyes, and greatly impair the transparency. Unless otherwise specified, it is preferably 0.001 to 0.1 μm, preferably 0.005 μm to 0 μm in terms of easy improvement in mechanical properties such as tear strength and excellent transparency. Particularly preferred is .05 μm. In addition, an average primary particle diameter is calculated | required by arithmetically averaging the diameter of the arbitrary 50 or more primary particles observed using the transmission electron microscope (TEM).

(Dispersing aid)
Examples of the dispersion aid (C) used in the present invention include glycerin ester compounds, adipic acid ester compounds, polyether ester compounds, phthalic acid ester compounds, isosorbide ester compounds, polycaprolactone compounds, and the like. Is exemplified. Among these, since it has excellent affinity for resin components and is difficult to bleed, modified glycerin compounds such as glycerin diacetomonolaurate, glycerin diacetomonocaprylate, glycerin diacetomonodecanoate; diethylhexyl adipate, dioctyl adipate, Adipic acid ester compounds such as diisononyl adipate; Polyether ester compounds such as polyethylene glycol dibenzoate, polyethylene glycol dicaprylate, and polyethylene glycol diisostearate are preferred, and those containing many biomass-derived components It is particularly preferable because the degree of biomass can be increased. Examples of such a dispersion aid include “Rikemar” (registered trademark) PL series manufactured by Riken Vitamin Co., Ltd. and Polysorb series manufactured by ROQUETTE. One type of dispersing aid can be used alone, or two or more types can be used in combination.

  The blending amount (total blending amount) of the dispersion aid (C) in the present invention is 8 to 23 parts by weight with respect to 100 parts by weight of the total amount of the aliphatic polyester (A) blended in the present invention. If it is less than 8 parts by weight, the function as a dispersion aid for silica (B) may not be sufficiently exhibited, or an aliphatic aromatic polyester such as polybutylene adipate terephthalate (PBAT) or polybutylene succinate terephthalate (PBST). When combined with (D), there may be a case where a sufficient improvement effect cannot be exhibited with respect to mechanical properties such as tear strength. On the other hand, if it exceeds 23 parts by weight, it may cause bleeding out. The amount of the dispersion aid (C) is preferably 13 parts by weight or more, more preferably 15 parts by weight or more, and preferably 22 parts by weight or less, more preferably 21 parts by weight or less.

(Aliphatic aromatic polyester)
Examples of the aliphatic aromatic polyester (D) used in the present invention include polybutylene adipate terephthalate (PBAT), polybutylene sebacate terephthalate, polybutylene azelate terephthalate, and polybutylene succinate terephthalate (PBST). Polybutylene adipate terephthalate (PBAT) refers to a random copolymer of 1,4-butanediol, adipic acid and terephthalic acid. Among them, as described in JP-T-10-508640, etc. (A) mainly 35 to 95 mol% of adipic acid or an ester-forming derivative thereof or a mixture thereof, 5 to 65 mol% of terephthalic acid or an ester-forming derivative thereof or a mixture thereof (the total of individual mol% is 100 mol) %) To a mixture containing (b) butanediol (provided that the molar ratio of (a) to (b) is 0.4: 1 to 1.5: 1). PBAT is preferred. Examples of commercially available PBAT include “Ecoflex F blend C1200” (registered trademark) manufactured by BASF. Polybutylene succinate terephthalate (PBST) means that the part of adipic acid or its ester-forming derivative of PBAT is replaced with sebacic acid or its ester-forming derivative. As a commercial product of PBST, BASF “Ecoflex FS blend B1100” (registered trademark) manufactured by the company, etc. may be mentioned. Moreover, aliphatic aromatic polyester (D) can also be used individually by 1 type, and can also be used in combination of 2 or more type. In the present invention, mechanical properties such as tear strength can be further improved by combining the aliphatic aromatic polyester (D) and the aliphatic polyester (A).

  The content (blending amount) of the aliphatic aromatic polyester (D) in the aliphatic polyester resin composition of the present invention is not particularly limited, but is 10 to 900 parts by weight with respect to 100 parts by weight of the aliphatic polyester (A). Is preferable, more preferably 25 to 400 parts by weight, still more preferably 40 to 250 parts by weight. By setting it as 10 weight part or more, there exists a tendency which increases the melt tension of the whole resin composition and improves a moldability and productivity. On the other hand, when the amount is 900 parts by weight or less, tackiness, which is a defect of the aliphatic aromatic polyester (D), is suppressed, and productivity tends to be improved or efficient biodegradability tends to be expressed.

  Moreover, the aliphatic polyester resin composition of the present invention may contain an organic or inorganic filler as long as the effects of the present invention are not impaired. Among these, from the viewpoint of biodegradability and carbon neutral, for example, woody materials such as wood chips, wood flour, sawdust, etc., naturally derived materials such as rice husk, rice flour, starch, corn starch, rice straw, wheat straw, natural rubber Is preferred. These may be used alone or in combination of two or more. The amount of the organic or inorganic filler can be set as appropriate.

  In addition, the aliphatic polyester resin composition of the present invention includes fillers other than silica, pigments, dyes and other colorants, activated carbon, zeolite, etc., which are used as usual additives, as long as the effects of the present invention are not impaired. Odor absorbers, fragrances such as vanillin and dextrin, antioxidants, antioxidants, weather resistance improvers, UV absorbers, lubricants, mold release agents, water repellents, antibacterial agents, slidability improvers, and other additives One or two or more kinds of agents may be added. The blending amount of the additive can be appropriately set.

The method for producing an aliphatic polyester resin composition of the present invention includes the following first step and melt kneading step as essential steps.
First step: Step of mixing silica (B) and dispersion aid (C) into aliphatic polyester (A) Melt kneading step: Step of melt kneading the mixture obtained in the first step The first step is , A step for obtaining a mixture to be subjected to the melt-kneading step, and “mixing” in the step is usually carried out below the temperature at which the aliphatic polyester (A) melts, that is, means mixing in a non-molten state. To do.

(Material mixing method before melt kneading: first step, etc.)
The manufacturing method of the aliphatic polyester resin composition of the present invention may be a step of mixing the aliphatic polyester (A) with the silica (B) and the dispersion aid (C), and in this step, other components are further added. You may mix. Examples of other components include aliphatic aromatic polyester (D). That is, the first step may be a step of mixing the aliphatic polyester (A) with silica (B), the dispersion aid (C), and the aliphatic aromatic polyester (D). The aliphatic polyester (A), silica (B), dispersion aid (C), and aliphatic aromatic polyester (D) to be mixed in the step are respectively (especially aliphatic polyester (A) and aliphatic aromatic polyester. Polyester (D)) may be the total amount constituting the aliphatic polyester resin composition of the present invention, or may be a partial amount. In the case of a partial amount, the remainder can be blended, for example, in a melt-kneading step. The mixing of the silica (B), the dispersion aid (C) and the aliphatic aromatic polyester (D) with respect to the aliphatic polyester (A) may be carried out simultaneously or sequentially.

(Melt-kneading method; melt-kneading step)
In the melt-kneading step of the method for producing the aliphatic polyester resin composition of the present invention, a known kneader such as a single screw extruder, a twin screw extruder, a planetary roller extruder, a Banbury mixer, or the like can be used. Of these, a twin screw extruder is preferred because of its versatility and ease of control of silica (B) distribution / dispersion and shearing. Moreover, as a setting condition of the melt-kneader, it is preferable to set the cylinder setting temperature to 180 ° C. or lower because thermal decomposition of the aliphatic polyester (A) can be suppressed. In the said process, you may mix | blend aliphatic polyester (A) (the remaining aliphatic polyester (A) which was not mixed in the 1st process), an aliphatic aromatic polyester (D), etc. further. As a blending method, a known method can be employed. For example, blending using a feeder such as a side feeder can be performed.

  Moreover, the melt-kneading process can be performed in one stage, or can be performed in two or more stages. For example, when the melt-kneading step is carried out in two stages, for example, first, a melt-kneaded product of aliphatic polyester (A), silica (B) and dispersion aid (C) is obtained in the first melt-kneading step, Then, it can implement by melt-kneading the said kneaded material and aliphatic aromatic polyester (D) in a 2nd melt-kneading process.

(Aliphatic aromatic polyester composite (mixed))
As described above, the aliphatic polyester resin composition of the present invention may be combined with the aliphatic aromatic polyester (D) during or after the production of the aliphatic polyester resin composition. That is, the manufacturing method of the aliphatic polyester resin composition of this invention may include the process of mixing aliphatic aromatic polyester (D) besides the above-mentioned essential process. The mixing of the aliphatic aromatic polyester (D) may be performed by melt kneading (for example, it may be performed in the above-described melt kneading step) or may be performed by non-melt kneading (for example, the above-mentioned). In the first step). More specifically, as a composite method (mixing method) of the aliphatic aromatic polyester (D), a base in which a mixture of the aliphatic polyester (A), the silica (B), and the dispersion aid (C) is put into an extruder. You may supply with a separate feeder from the same location as a hopper, and may carry out side feed. Or after manufacturing the composition (aliphatic polyester resin composition) which consists of aliphatic polyester (A), a silica (B), and a dispersion aid (C) once, the said composition and aliphatic aromatic polyester (D) And may be combined by melt kneading after dry blending. The mixing of the aliphatic aromatic polyester (D) is preferably carried out by melt kneading (that is, carried out in the above-mentioned melt kneading step) from the viewpoint of productivity. In particular, the aliphatic polyester (A), silica ( More preferably, the aliphatic aromatic polyester (D) is melt-kneaded with the melt-kneaded product of B) and the dispersion aid (C).

  The aliphatic polyester resin composition obtained by the method for producing an aliphatic polyester resin composition of the present invention is subjected to a molding process such as being singly or complexed with various resins or multilayered with various resins. be able to. For example, as a forming method for processing into a film or a sheet, a known method such as an inflation method or a T-die extrusion method can be used. Specific conditions may be set as appropriate. For example, in the inflation method, the pellet is dried by a dehumidifying dryer or the like before inflation molding until the moisture content of the pellets is 500 ppm or less, the cylinder set temperature is 100 to 160 ° C., the adapter The set temperature of the die is preferably 130 to 160 ° C.

  When processed into a film or sheet, the aliphatic polyester resin composition of the present invention has no problem of poor appearance due to silica non-dispersion, and can exhibit higher tear strength particularly when combined with PBAT or PBST. it can.

  Although there is no strict regulation on the thickness of the film or sheet, a thickness of about 1 to 100 μm is generally called a film, and a thickness exceeding 100 μm to about 2 mm is called a sheet.

  The film or sheet of the present invention can be suitably used in agriculture, fishery, forestry, horticulture, medicine, sanitary products, food industry, clothing, non-clothing, packaging, automobiles, building materials, and other fields. For example, for agricultural films, fumigation sheets for forestry, bundling tape including flat yarn, rooting films for plants, diaper back sheets, packaging sheets, shopping bags, garbage bags, draining bags, and other compost bags It is done.

  The method for producing an aliphatic polyester resin composition of the present invention may include a step of molding the aliphatic polyester resin composition. This molding process may be performed continuously with the above-described melt-kneading process or may be performed discontinuously. Examples of the forming method include the above-described known methods. When the manufacturing method of the aliphatic polyester resin composition of the present invention includes a step of molding, an aliphatic polyester resin composition molded by the above manufacturing method (that is, a molded body) is obtained. It does not specifically limit as a molded object, For example, a film and a sheet | seat are mentioned as mentioned above.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by the said Example.

[Aliphatic polyester]
The aliphatic polyester A-1 used in this example was obtained according to the method described in International Publication No. 2013/147139, and the average particle having a 3-hydroxyhexanoate (3HH) composition of 11.2 mol% was obtained. It is a particulate PHBH (powder) having a diameter of 330 μm. The weight average molecular weight of the PHBH measured by GPC was 570,000.

  In the method described in International Publication No. 2013/147139, the aliphatic polyester A-2 was filtered to remove cell residue, concentrated with an evaporator until the total volume became 30 mL, and then gradually added 90 mL of hexane. Is a particulate PHBH (powder) having an average particle diameter of 150 μm, obtained by reducing the addition rate of hexane and the stirring rate. The weight average molecular weight of the PHBH measured by GPC was 570,000.

  In the method described in International Publication No. 2013/147139, the aliphatic polyester A-3 was filtered to remove cell residue, concentrated with an evaporator until the total volume became 30 mL, and then gradually added 90 mL of hexane to add PHA. Is a particulate PHBH (powder) having an average particle size of 670 μm, obtained by increasing the addition rate of hexane and the stirring rate. The weight average molecular weight of the PHBH measured by GPC was 570,000.

  Aliphatic polyester A-4 is a method described in International Publication No. 2013/147139. After filtering the cell residue, concentrating it with an evaporator until the total volume becomes 30 mL, gradually adding 90 mL of hexane to add PHA. It is particulate PHBH (powder) having an average particle size of 800 μm obtained by extremely increasing the addition rate of hexane and the stirring rate during precipitation. The weight average molecular weight of the PHBH measured by GPC was 570,000.

  Aliphatic polyester A-5 is a method described in International Publication No. 2013/147139. After filtering the cell residue and concentrating with an evaporator until the total volume becomes 30 mL, 90 mL of hexane is gradually added to remove PHA. Is a particulate PHBH (powder) having an average particle size of 80 μm obtained by extremely reducing the addition rate of hexane and the stirring rate. The weight average molecular weight of the PHBH measured by GPC was 570,000.

In the following examples and comparative examples, the following raw materials were also used.
A-6: EM5400F [P3HB4HB] (manufactured by Ecomann) Average particle size 299 μm

[silica]
B-1: Nipsil LP [wet silica] (manufactured by Tosoh Silica)
B-2: R972 [dry silica] (made by Nippon Aerosil Co., Ltd.)
The average primary particle diameter of silica shown in Table 1 is the manufacturer's catalog value.

[Dispersion aid]
C-1: Riquemar PL012 [glycerin ester compound] (manufactured by Riken Vitamin Co., Ltd.)
C-2: Polysorb ID46 [isosorbide ester compound] (manufactured by ROQUETTE)

[Aliphatic aromatic polyester]
D-1: Ecoflex F Blend C1200 (BASF): PBAT
D-2: Ecoflex FS Blend B1100 (manufactured by BASF): PBST
D-3: GF106 / 02 (manufactured by Biotec): PBAT / starch = 66/34

[Example 1]
(Production of aliphatic polyester resin composition)
Aliphatic polyester A-1, silica B-1, and dispersion aid C-1 were dry blended at the blending ratio shown in Table 1 (the blending ratio in the table indicates parts by weight; the same applies hereinafter). Next, using the same direction meshing type twin screw extruder (Toshiba Machine Co., Ltd .: TEM-26SS), the mixed raw material is charged from the hopper, set temperature 120 to 140 ° C., screw rotation speed 100 rpm (exit resin temperature 155 ° C.). And kneaded to obtain a polyester resin composition. The outlet resin temperature was measured by directly measuring the molten resin coming out of the die with a K-type thermocouple. The aliphatic polyester resin composition was drawn from a die in a strand shape and cut into a pellet shape.

(Film production)
Using a single-screw extruder Labo Plast Mill (Toyo Seiki Seisakusho, 20C200 type) equipped with a T-type die with a width of 150 mm and a lip of 0.25 mm, the above conditions were obtained at a die setting temperature of 160 ° C. and a screw rotation speed of 40 rpm. The obtained aliphatic polyester resin composition was extruded and taken up at a rate of 1 m / min with a cooling roll adjusted to 60 ° C. to obtain a 40 μm thick film.

(Silica dispersibility [appearance] evaluation)
10 cases where an area of 10 cm in width × 30 cm in length is arbitrarily selected from the film obtained above, and it can be confirmed in all 10 places that the number of fish eyes of 40 μm or more is 1 or less in each place. The case where two or more fish eyes were confirmed even at one of the locations was marked as x. The evaluation results are shown in Table 1. The fish eye here is, for example, a solid that does not melt even when heated to 250 ° C. with a temperature variable polarization microscope, and does not maintain a solid state by melting during heating up to 250 ° C. It was. That is, the fish eye refers to a silica aggregate having a size of 40 μm or more.

(Average particle size)
The average primary particle diameter of silica is described in the manufacturer's catalog. The particle diameter of the aliphatic polyester is measured with Microtrack 10.5.3-22ST manufactured by NIKKISO, and the particle diameter at 50% cumulative is taken as the average particle diameter. Described. It was confirmed that all the raw materials showed one peak particle size distribution.

(Silica adsorption moisture content)
Volatile content at 160 ° C. was measured using an electromagnetic balance MX-50 manufactured by Kensei Kogyo Co., Ltd., and the value was described as a moisture content (adsorbed moisture content).

(Bleed-out evaluation)
A 10 cm width × 100 cm length was cut out from the film obtained above, and a line was drawn in the length direction with one at the center and two at a distance of 4 cm from the center with an oil-based magic manufactured by ZEBRA. It was left for 6 months at 23 ° C. and 50% RH, and the bleeding of the magic wire was confirmed every week after molding. Bleeding was confirmed visually and by rubbing with a finger. The case where there was no bleeding even after 6 months was marked as ◯, and the case where bleeding occurred during 6 months was marked as x. The evaluation results are shown in Table 1.

[Examples 2 to 4]
Except for changing the raw material species to be blended, the blending ratio and the silica water content as shown in Table 1, in the same manner as in Example 1, an aliphatic polyester resin composition and a film comprising the same were obtained, and silica was obtained using the film. Dispersibility and bleed-out were evaluated. The evaluation results are shown in Table 1.

[Comparative Example 1]
Except for changing the aliphatic polyester as shown in Table 1, an aliphatic polyester resin composition and a film comprising the same were obtained in the same manner as in Example 1, and silica dispersibility and bleedout were evaluated using the film. did. The evaluation results are shown in Table 1.

[Comparative Example 2]
An attempt was made to obtain an aliphatic polyester resin composition in the same manner as in Example 1 except that the aliphatic polyester was changed as shown in Table 1, but the particle size of the aliphatic polyester was too small and the bulk density was low. Thus, stable feeding was impossible, and melt-kneading could not be performed unless the discharge was extremely lowered. Therefore, it was judged that acquisition of a resin composition was impossible.

[Comparative Example 3]
Except having changed the compounding quantity of a silica and a dispersion | distribution adjuvant as shown in Table 1, it carried out similarly to Example 1, and obtained the aliphatic polyester resin composition and the film which consists of it, The dispersibility of a silica using the said film And assessed the bleedout. The evaluation results are shown in Table 1.

  When Example 1 and Comparative Examples 1 and 2 are compared, using an aliphatic polyester that is outside the proper range defined in the present invention as in Comparative Examples 1 and 2 causes problems in the dispersibility of silica and the production of the resin composition. It can be seen that it occurs. In addition, when Example 1 and Comparative Example 3 are compared, if the amount of silica and the dispersion aid are outside the proper range specified in the present invention as in Comparative Example 3, there is a problem in the dispersibility and bleed-out property of silica. It turns out that occurs. On the other hand, as shown in Examples 1 to 4, it can be seen that according to the production method defined in the present invention, an aliphatic polyester resin composition having good dispersibility can be produced even if various materials are used.

[Examples 5 to 9]
Using the aliphatic polyester resin composition produced in Example 1, this was mixed with the aliphatic aromatic polyesters D-1 to D-3 at the compounding ratio shown in Table 2, and the resulting mixture was set at a set temperature of 140 ° C. ( Outlet resin temperature 160 ° C.) and melt kneading at a screw rotation speed of 100 rpm to obtain an aliphatic polyester resin composition. The aliphatic polyester resin composition was drawn from a die in a strand shape and cut into a pellet shape.

  Subsequently, the obtained aliphatic polyester resin composition was obtained using a molding machine similar to that used in Example 1 to obtain a film having a thickness of 40 μm at a die setting temperature of 160 ° C., and silica dispersibility and bleed out were evaluated. . The evaluation results are shown in Table 2.

(Measurement of tear strength)
Using the obtained film (sheet), the tear strength in the MD direction was measured in accordance with JIS 8116 with an Elmendorf tear strength measuring instrument (manufactured by Kumagai Riki Kogyo Co., Ltd.). The tear strength measurement results are shown in Table 3.

[Comparative Examples 4 and 5]
Instead of the aliphatic polyester resin composition produced in Example 1, the aliphatic polyester resin composition produced in Comparative Examples 1 and 3 was used, respectively, and the blending amount of the aliphatic aromatic polyester D-1 is shown in Table 2. In the same manner as in Example 6, except that the aliphatic polyester resin composition and the film comprising the same were obtained, the dispersibility of silica, bleed out, and tear strength were evaluated using the film. The evaluation results are shown in Table 2.

  When Example 6 and Comparative Examples 4 and 5 were compared, an aliphatic polyester resin composition with good dispersibility of silica and an aliphatic aromatic polyester as in Example 6 were separately melt-kneaded and combined. It can be seen that a film having good dispersibility of silica and a sufficiently large tear strength of 30 N / mm can be obtained. Further, as can be seen from Examples 5 to 9, the aliphatic polyester resin composition produced by the production method of the aliphatic polyester resin composition of the present invention, for example, the aliphatic polyester resin composition obtained in Example 1 was used. If used, even if it is compounded with various aliphatic aromatic polyesters (D), or even if it is compounded with the aliphatic aromatic polyester (D), the dispersibility of the silica is good, and the tear strength It can be seen that a sufficiently large film can be obtained. On the other hand, a film molded body composited with an aliphatic aromatic polyester (D) using an aliphatic polyester resin composition having poor silica dispersibility and bleed property is a silica dispersibility (appearance), bleed property, tearing. It can be seen that there is a problem with one or more of the strengths.

Claims (7)

A method for producing an aliphatic polyester resin composition containing 5 to 23 parts by weight of silica (B) and 8 to 23 parts by weight of a dispersion aid (C) with respect to 100 parts by weight of the aliphatic polyester (A),
A first step of mixing the aliphatic polyester (A) with the silica (B) and the dispersion aid (C);
A melt-kneading step of melt-kneading the mixture obtained in the first step,
The method for producing an aliphatic polyester resin composition, wherein the aliphatic polyester (A) to be mixed in the first step is a particulate aliphatic polyester having an average particle diameter of 100 to 700 μm.   The aliphatic polyester resin according to claim 1, wherein the first step is a step of mixing the aliphatic polyester (A) with the silica (B), the dispersion aid (C) and the aliphatic aromatic polyester (D). A method for producing the composition.   The manufacturing method of the aliphatic polyester resin composition of Claim 1 including the process of melt-kneading the obtained kneaded material and aliphatic aromatic polyester (D) after a melt-kneading process.   The method for producing an aliphatic polyester resin composition according to any one of claims 1 to 3, wherein the aliphatic polyester (A) to be mixed in the first step is a particulate aliphatic polyester having an average particle diameter of 200 to 450 µm. .   The aliphatic group according to any one of claims 1 to 4, wherein the silica (B) to be mixed in the first step is a silica having an adsorbed water amount volatilized at 160 ° C of 0.5 wt% or more and 7 wt% or less. A method for producing a polyester resin composition.   The dispersion aid (C) is at least one selected from the group consisting of a glycerin ester compound, an adipic acid ester compound, a polyether ester compound and an isosorbide ester compound. The manufacturing method of the aliphatic polyester resin composition of one term.   The method for producing an aliphatic polyester resin composition according to any one of claims 1 to 6, wherein the aliphatic polyester resin composition is a molded body.