JP2014001263A - Aliphatic polycarbonate resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aliphatic polycarbonate resin composition which is excellent in mechanical characteristics, particularly tensile strength.SOLUTION: An aliphatic polycarbonate resin composition contains cellulose fiber at a ratio of 0.1-50 pts.mass relative to 100 pts.mass of aliphatic polycarbonate resin.

Description

  The present invention relates to an aliphatic polycarbonate resin composition. More specifically, the present invention relates to an aliphatic polycarbonate resin composition having excellent mechanical properties, particularly tensile strength.

  Since the industrial revolution, human beings have built a modern society by consuming large amounts of fossil fuels, but on the other hand, increasing the concentration of carbon dioxide in the atmosphere and further promoting this increase through environmental destruction such as deforestation. Yes. Global warming is caused by the increase in greenhouse gases such as carbon dioxide, chlorofluorocarbons and methane in the atmosphere, so reducing the atmospheric concentration of carbon dioxide, which has a high contribution to global warming, It is extremely important, and various studies such as emission regulations and immobilization are being carried out on a global scale.

  Among them, the copolymerization reaction between carbon dioxide and epoxides discovered by Inoue et al. Is expected as a reaction responsible for solving the global warming problem. Research is also actively conducted from the viewpoint of the use of carbon dioxide as a non-patent document 1 (see Non-Patent Document 1).

  Aliphatic polycarbonate obtained by copolymerization of epoxide and carbon dioxide has transparency and can be used for general moldings, films, fibers, etc. because it is completely decomposed by heating above a predetermined temperature. In addition, it can be used as an optical material such as an optical fiber or an optical disk, or as a thermally decomposable material such as a ceramic binder or lost foam casting.

  However, since the mechanical performance of aliphatic polycarbonate is at a level that does not reach that of general-purpose resins such as polyethylene, polypropylene, and polymethyl methacrylate, its application is remarkably limited. Consideration has been made.

  For example, Non-Patent Document 2 describes a resin composition obtained by blending calcium carbonate with polypropylene carbonate. Patent Document 1 discloses a novel compound excellent in mechanical properties, in which a methacrylic resin or an aliphatic polyester is compounded as a second component with respect to an aliphatic polycarbonate, and a vinyl resin is added in a specific proportion as a third component. A ternary carbon dioxide-derived aliphatic polycarbonate composite is described.

  Patent Document 2 proposes a polyalkylene carbonate resin composition and a polyalkylene carbonate resin composition excellent in tensile strength, bending strength, and impact strength having inorganic fibers or synthetic fibers, in order to obtain sufficient tensile strength. Requires addition of 20% by mass or more of inorganic fiber or synthetic fiber, and there is a risk that the breaking strain may be extremely reduced.

WO2010 / 053110 Publication JP 2007-119609 A

Macromolecular Synthesis, Vol. 7, p. 87 (1969) Journal of Polymer Science Part B Polymer Physics, Vol. 41, p. 1806 (2003)

  As described above, various improvements have been proposed with respect to the mechanical strength of aliphatic polycarbonate, but none of them has achieved satisfactory performance. An object of the present invention is to provide an aliphatic polycarbonate resin composition having excellent mechanical properties, particularly tensile strength.

The present inventor has intensively studied to achieve the above-described object. As a result, the inventors have found that an aliphatic polycarbonate resin composition containing a specific proportion of cellulose fibers with respect to aliphatic polypropylene carbonate is excellent in mechanical properties, particularly tensile strength, and has completed the present invention. That is, the present invention
Item 1. An aliphatic polycarbonate resin composition containing cellulose fibers at a ratio of 0.1 to 50 parts by mass with respect to 100 parts by mass of the aliphatic polycarbonate resin;
Item 2. Item 2. The aliphatic polycarbonate resin composition according to Item 1, wherein the aliphatic polycarbonate resin is obtained by polymerizing carbon dioxide and alkylene oxide in the presence of a metal catalyst;
Item 3. Item 2. The aliphatic polycarbonate resin composition according to Item 1, wherein the aliphatic polycarbonate resin is a polypropylene carbonate resin;
Item 4. Item 5. The aliphatic polycarbonate resin composition according to Item 1, wherein the cellulose fiber has a fiber diameter of 10 nm to 500 µm and an aspect ratio (fiber length / fiber diameter) of 20 to 10,000; Item 12. The aliphatic polycarbonate resin composition according to Item 1, wherein the tensile strength is 25 MPa or more.

  The aliphatic polycarbonate resin composition according to the present invention can improve mechanical properties, particularly tensile strength, by containing cellulose fibers in a specific ratio in the aliphatic polycarbonate resin.

Hereinafter, the aliphatic polycarbonate resin composition concerning this invention is demonstrated concretely.
The aliphatic polycarbonate resin composition of the present invention contains cellulose fibers in a specific ratio in the aliphatic polycarbonate resin.

  The aliphatic carbonate resin used in the present invention is not particularly limited, and for example, a resin obtained by polymerizing an alkylene oxide and carbon dioxide in the presence of a metal catalyst is preferably used.

  Examples of the alkylene oxide include ethylene oxide, propylene oxide, 1-butene oxide, 2-butene oxide, isobutylene oxide, 1-pentene oxide, 2-pentene oxide, 1-hexene oxide, 1-octene oxide, 1-decene oxide, Cyclopentene oxide, cyclohexene oxide, styrene oxide, vinylcyclohexene oxide, 3-phenylpropylene oxide, 3,3,3-trifluoropropylene oxide, 3-naphthylpropylene oxide, 3-phenoxypropylene oxide, 3-naphthoxypropylene oxide, butadiene Examples thereof include monooxide, 3-vinyloxypropylene oxide and 3-trimethylsilyloxypropylene oxide. Among these alkylene oxides, ethylene oxide and propylene oxide are preferably used, and propylene oxide is more preferably used from the viewpoint of high polymerization reactivity with carbon dioxide. These alkylene oxides may be used alone or in combination of two or more.

  Examples of the metal catalyst include an aluminum catalyst and a zinc catalyst. Among these, a zinc catalyst is preferably used because it has a high polymerization activity in the polymerization reaction between alkylene oxide and carbon dioxide, and among the zinc catalysts, an organic zinc catalyst is preferably used.

  Examples of the organic zinc catalyst include organic zinc catalysts such as zinc acetate, diethyl zinc, and dibutyl zinc; primary amines, divalent phenols, divalent aromatic carboxylic acids, aromatic hydroxy acids, aliphatic dicarboxylic acids, and fatty acids. And an organozinc catalyst obtained by reacting a compound such as an aromatic monocarboxylic acid with a zinc compound. Among these organozinc catalysts, an organozinc catalyst obtained by reacting a zinc compound, an aliphatic dicarboxylic acid and an aliphatic monocarboxylic acid is preferably used because it has higher polymerization activity.

  The amount of the metal catalyst used in the polymerization reaction is preferably 0.001 to 20 parts by mass and more preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of the alkylene oxide. When the usage-amount of a metal catalyst is less than 0.001 mass part, there exists a possibility that a polymerization reaction may become difficult to advance. Moreover, when the usage-amount of a metal catalyst exceeds 20 mass parts, there exists a possibility that there may be no effect corresponding to a usage-amount and it may become economical.

  In the polymerization reaction, the method of reacting alkylene oxide and carbon dioxide in the presence of a metal catalyst is not particularly limited. For example, the alkylene oxide, the metal catalyst, and, if necessary, the reaction solvent are added to an autoclave. After charging and mixing, there is a method in which carbon dioxide is injected and reacted.

  The reaction solvent used as necessary in the polymerization reaction is not particularly limited, and various organic solvents can be used. Specific examples of the organic solvent include aliphatic hydrocarbon solvents such as pentane, hexane, octane, decane, and cyclohexane; aromatic hydrocarbon solvents such as benzene, toluene, and xylene; chloromethane, methylene dichloride, and the like. , Chloroform, carbon tetrachloride, 1,1-dichloroethane, 1,2-dichloroethane, ethyl chloride, trichloroethane, 1-chloropropane, 2-chloropropane, 1-chlorobutane, 2-chlorobutane, 1-chloro-2-methylpropane, chloro Halogenated hydrocarbon solvents such as benzene and bromobenzene; carbonate solvents such as dimethyl carbonate, diethyl carbonate, and propylene carbonate.

  It is preferable that the usage-amount of the said reaction solvent is 300-10000 mass parts with respect to 100 mass parts of alkylene oxide from a viewpoint of making reaction smooth.

  The working pressure of carbon dioxide used in the polymerization reaction is not particularly limited, but is usually preferably 0.1 to 20 MPa, more preferably 0.1 to 10 MPa, and 0.1 to 5 MPa. More preferably. When the working pressure of carbon dioxide exceeds 20 MPa, there is a possibility that it is not economical because there is no effect corresponding to the working pressure.

  Although the polymerization reaction temperature in the said polymerization reaction is not specifically limited, It is preferable that it is 30-100 degreeC, and it is more preferable that it is 40-80 degreeC. When the polymerization reaction temperature is less than 30 ° C., the polymerization reaction may take a long time. On the other hand, when the polymerization reaction temperature exceeds 100 ° C., side reactions occur and the yield may decrease. The polymerization reaction time varies depending on the polymerization reaction temperature and cannot be generally specified, but it is usually preferably 2 to 40 hours.

  After completion of the polymerization reaction, an aliphatic polycarbonate resin can be obtained by filtering off by filtration or the like, washing with a solvent or the like if necessary, and drying.

  The number average molecular weight of the aliphatic polycarbonate resin used in the present invention is preferably 5,000 to 1,000,000, and more preferably 10,000 to 500,000. When the number average molecular weight of the aliphatic polycarbonate resin is less than 5,000, the tensile strength of the resulting aliphatic polycarbonate resin composition may be lowered. In addition, when the number average molecular weight of the aliphatic polycarbonate resin exceeds 1,000,000, when the aliphatic polycarbonate resin is dissolved in a solvent, there is a possibility that the viscosity increases and the handleability is deteriorated. The number average molecular weight is a value measured by the method described later.

  As the raw material cellulose of the cellulose fiber used in the present invention, plants (for example, wood, bamboo, hemp, jute, kenaf, farmland waste, cloth, pulp, recycled pulp, waste paper), animals (for example, ascidians), algae Those originating from microorganisms (for example, acetic acid bacteria (Acetobacter)), microorganism products, etc. are known, and any of them can be used in the present invention. Preferred is cellulose derived from plants or microorganisms, and more preferred is cellulose derived from plants.

  Examples of the cellulose fiber used in the present invention include those produced by various known methods. For example, it is produced by mechanically defibrating cellulose with a high-pressure homogenizer, a grinder, a ball mill, high-pressure jet water or the like. Further, it is produced by performing defibration by a chemical method such as a 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) catalyst, or by performing defibration using an ionic liquid. In addition, in this invention, as long as a cellulose is a fiber state, about the manufacturing method, there is no restriction | limiting, You may use a commercially available thing.

  Commercially available products include “BiNF-IS Cellulose, cellulose content 5%” manufactured by Sugino Machine, “Cerish KY-100G, cellulose content 10%” manufactured by Daicel Corporation, “TEMPO oxidized pulp product, cellulose content manufactured by Nippon Paper Industries, Ltd.” 7% "," KC Flock "manufactured by Nippon Paper Chemicals," Cotton Linter Pulp Sheet "manufactured by Bakay Technologies, and" Wood Pulp Sheet "manufactured by Nippon Paper Chemicals, etc.

  The average fiber diameter of the cellulose fibers used in the present invention is preferably 10 nm to 500 μm, more preferably 20 nm to 400 μm, still more preferably 25 nm to 300 μm. The length of the cellulose fiber is not particularly limited, but the aspect ratio (fiber length / fiber width) is preferably 10 to 10,000, more preferably 20 to 5,000. . When the aspect ratio is less than 10, the dispersion state may be deteriorated.

  In the aliphatic polycarbonate resin composition of the present invention, the content of the cellulose fiber is preferably 0.1 to 50 parts by mass, more preferably 1 to 40 parts by mass with respect to 100 parts by mass of the aliphatic polycarbonate resin. When content of a cellulose fiber exceeds 50 mass parts, when manufacturing an aliphatic polycarbonate resin composition, workability falls and there exists a possibility that an appropriate aliphatic polycarbonate resin composition may not be obtained. When content of a cellulose fiber is less than 0.1 mass part, there exists a possibility that the addition effect of a cellulose fiber cannot be exhibited.

  The aliphatic polycarbonate resin composition of the present invention preferably has a tensile strength measured by a measurement method described later of 25 MPa or more.

  The production method of the aliphatic polycarbonate resin composition according to the present invention is not particularly limited. For example, the method of melt-kneading the aliphatic polycarbonate resin and the cellulose fiber, the aliphatic polycarbonate resin and the cellulose fiber between powders Examples thereof include a method of mixing, a method of dissolving the aliphatic polycarbonate resin in a solvent and the like and then mixing the cellulose fibers and then removing the solvent. Among these production methods, a method of melt-kneading an aliphatic polycarbonate resin and cellulose fibers is preferably used from the viewpoint that the composition can be easily produced and a uniform composition can be obtained.

  The method for melt-kneading the aliphatic polycarbonate resin and the cellulose fiber is not particularly limited, and examples thereof include a method for melt-kneading using a vent type twin-screw extruder, a Banbury mixer, a kneader, a kneading roll or the like.

  In the aliphatic polycarbonate resin composition of the present invention, as long as the effect is not impaired, as an additive, an antioxidant, an antishrink agent, an antistatic agent, an ultraviolet absorber, a heat stabilizer, a weather stabilizer, Release agents, lubricants, impact modifiers, plasticizers, flame retardants, antibacterial agents, preservatives, and the like may be added as appropriate.

  The present invention will be specifically described below with reference to production examples, examples and comparative examples, but the present invention is not limited to these examples.

[Evaluation]
The number average molecular weight of the aliphatic polycarbonate resin obtained by the production example and the tensile strength of the aliphatic polycarbonate resin composition obtained by the examples and comparative examples were measured and evaluated by the following methods.

(1) Number average molecular weight measurement A chloroform solution having an aliphatic polycarbonate resin concentration of 0.5% by mass was prepared and measured using a high performance liquid chromatograph. The molecular weight was calculated by comparing with polystyrene having a known number average molecular weight measured under the same conditions. The measurement conditions are as follows.
Model: HLC-8020 (manufactured by Tosoh Corporation)
Column: GPC column (trade name of Tosoh Corporation, TSK GEL Multipore H _XL- M)
Column temperature: 40 ° C
Eluent: Chloroform Flow rate: 1 mL / min

(2) Tensile test: Based on JIS K7161, tensile stress, breaking stress and breaking strain were measured using the following test piece and measuring device.
Test piece: 1BA type (small test piece)
Measuring machine: Shimadzu Autograph AGS-J type

i) Tensile stress (MPa): Tensile stress at 5% and 10% strain
ii) Tensile stress (MPa): Maximum value and tensile stress at break
iii) Breaking strain (%): Elongation at break

(3) Anti-blocking property Two release sheets of 20 * 50 * 2 mmt were sandwiched between two upper 20 * 20 mm sheets, overlapped, allowed to stand at room temperature for 24 hours, and then the adhesion state was confirmed.
Evaluation method: The overlapped sheets were peeled off by hand to confirm the peeled state.
Evaluation result: ○: No adhesion △: Slightly adhered but easily peeled off
X: Adhesion does not peel off much

[Production Example 1] (Production of organozinc catalyst)
In a 300 mL four-necked flask equipped with a stirrer, a nitrogen gas inlet tube, a thermometer, and a reflux condenser, zinc oxide 8.1 g (100 mmol), glutaric acid 12.7 g (96 mmol), acetic acid 0.1 g ( 2 mmol) and 130 g (150 mL) of toluene. Next, after the inside of the reaction system was replaced with a nitrogen atmosphere, the temperature was raised to 55 ° C., and the reaction was performed by stirring at the same temperature for 4 hours. Thereafter, the temperature was raised to 110 ° C., and the mixture was further stirred for 4 hours at the same temperature for azeotropic dehydration to remove only moisture, and then cooled to room temperature to obtain a reaction solution containing an organozinc catalyst.

  As a result of measuring IR for the organozinc catalyst obtained by separating a part of this reaction solution and filtering it (product name: AVATAR360, manufactured by Thermo Nicolet Japan Co., Ltd.), no peak based on the carboxylic acid group was observed. It was.

[Production Example 2] (Production of polypropylene carbonate)
After the inside of a 1 L autoclave system equipped with a stirrer, a gas introduction tube, and a thermometer was previously replaced with a nitrogen atmosphere, 8.0 mL of the reaction solution containing the organozinc catalyst obtained in Production Example 1 (1 organozinc catalyst was added) 0.0 g), 131 g (200 mL) of hexane, and 46.5 g (0.80 mol) of propylene oxide. Next, carbon dioxide was added under stirring to replace the inside of the reaction system with a carbon dioxide atmosphere, and carbon dioxide was charged until the inside of the reaction system became 1.5 MPa. Thereafter, the temperature was raised to 60 ° C., and a polymerization reaction was carried out for 6 hours while supplying carbon dioxide consumed by the reaction.

  After completion of the reaction, the autoclave was cooled and depressurized, filtered, and dried under reduced pressure to obtain 80.8 g of polypropylene carbonate. The number average molecular weight of the obtained polypropylene carbonate was 52,000.

[Example 1]
Linder pulp (manufactured by Bakay Technologies) pulverized product (mesh mill HA-2542, screen 0.35 mmΦ, manufactured by Horai Co., Ltd.) 5 parts by mass with respect to 95 parts by mass of polypropylene carbonate obtained in the same manner as in Production Example 2. Was added and kneaded. The kneading was performed at 100 ° C. and 60 rpm for 10 minutes using a pressure kneader (Laboplast Mill / 10C100 type, manufactured by Toyo Seiki Seisakusho). Next, the obtained kneaded product was pressed for 5 minutes at 100 ° C. under a pressure of 2 MPa · G using a press molding machine (40 ton heating press manufactured by Gonno Hydraulic Co., Ltd.) to produce a press sheet having a thickness of 2 mmt. A test dumbbell specimen was obtained.
When the tensile strength measurement of the polypropylene carbonate resin composition was performed using the obtained test piece, the tensile strength was 29 MPa.

[Example 2]
To 80 parts by mass of polypropylene carbonate obtained in the same manner as in Production Example 2, 400 parts by mass of a cellulose nanofiber aqueous dispersion (“BiNF-I-S cellulose, concentration 5% by mass” manufactured by Sugino Machine) was added and kneaded. The kneading was carried out using a pressure kneader (Laboplast Mill / 10C100, manufactured by Toyo Seiki Seisakusho Co., Ltd.) at 100 ° C. and 60 rpm for about 30 minutes, and the obtained kneaded product was press-molded. A press sheet having a thickness of 2 mmt was produced to obtain a dumbbell test piece for a tensile test.
When the tensile strength measurement of the polypropylene carbonate resin composition was performed using the obtained test piece, the tensile strength was 40 MPa.

[Example 3]
1 part by mass of pulverized wood pulp NPDS (manufactured by Nippon Paper Chemicals) (mesh mill HA-2542, screen 0.35 mmΦ, manufactured by Horai Co., Ltd.) with respect to 99 parts by mass of polypropylene carbonate obtained in the same manner as in Production Example 2. Was added and kneaded. The kneading was performed at 100 ° C. and 60 rpm for 10 minutes using a pressure kneader (Laboplast Mill / 10C100 type, manufactured by Toyo Seiki Seisakusho). Next, the obtained kneaded product was press-molded to produce a press sheet having a thickness of 2 mmt to obtain a dumbbell test piece for a tensile test.
When the tensile strength measurement of the polypropylene carbonate resin composition was performed using the obtained test piece, the tensile strength was 25 MPa.

[Example 4]
For 70 parts by mass of polypropylene carbonate obtained in the same manner as in Production Example 2, 30 parts by mass of pulverized cotton linter pulp (manufactured by Baccai) (mesh mill HA-2542, screen 0.35 mmΦ, manufactured by Horai Co., Ltd.) Added and kneaded. The kneading was performed at 100 ° C. and 60 rpm for 10 minutes using a pressure kneader (Laboplast Mill / 10C100 type, manufactured by Toyo Seiki Seisakusho). Next, the obtained kneaded product was press-molded to produce a press sheet having a thickness of 2 mmt to obtain a dumbbell test piece for a tensile test.
When the tensile strength measurement of the polypropylene carbonate resin composition was performed using the obtained test piece, the tensile strength was 49 MPa.

[Example 5]
To 90 parts by mass of polypropylene carbonate obtained in the same manner as in Production Example 2, 100 parts by mass of an aqueous cellulose nanofiber dispersion (“Serisch KY-100G, concentration 10% by mass” manufactured by Daicel Finechem) was added and kneaded. Using a pressure kneader (Laboplast Mill / 10C100, manufactured by Toyo Seiki Seisakusho Co., Ltd.), it was carried out for about 30 minutes while slowly blowing water at 100 ° C. and 60 rpm. A press sheet was prepared and a dumbbell test piece for tensile test was obtained.
When the tensile strength measurement of the polypropylene carbonate resin composition was performed using the obtained test piece, the tensile strength was 36 MPa.

[Example 6]
To 85 parts by mass of polypropylene carbonate obtained in the same manner as in Production Example 2, 15 parts by mass of cellulose powder (KC Flock W-100GK, manufactured by Nippon Paper Chemicals Co., Ltd.) was added and kneaded. The kneading was performed at 100 ° C. and 60 rpm for 10 minutes using a pressure kneader (Laboplast Mill / 10C100 type, manufactured by Toyo Seiki Seisakusho). Next, the obtained kneaded product was press-molded to produce a press sheet having a thickness of 2 mmt to obtain a dumbbell test piece for a tensile test.
When the tensile strength measurement of the polypropylene carbonate resin composition was performed using the obtained test piece, the tensile strength was 30 MPa.

[Comparative Example 1]
Polypropylene carbonate obtained in the same manner as in Production Example 2 was press-molded to obtain a test piece. When the tensile strength measurement was performed using the obtained test piece, the tensile strength was 9 MPa.

[Comparative Example 2]
To 90 parts by mass of polypropylene carbonate obtained in the same manner as in Production Example 2, 10 parts by mass of glass fiber powder (LS-5-300M, manufactured by Asahi Fiber Glass Co., Ltd., average particle size 12 μm) was added and kneaded. The kneading was performed at 100 ° C. and 60 rpm for 10 minutes using a pressure kneader (Laboplast Mill / 10C100 type, manufactured by Toyo Seiki Seisakusho). Next, the obtained kneaded product was press-molded to produce a press sheet having a thickness of 2 mmt to obtain a dumbbell test piece for a tensile test.

When the tensile strength measurement of the polypropylene carbonate resin composition was performed using the obtained test piece, the tensile strength was 12 MPa.
As is clear from Examples 1 to 6, the polypropylene carbonate resin composition according to the present invention is excellent in tensile strength. On the other hand, since the comparative example 1 does not contain cellulose fibers at a specific ratio, the tensile strength cannot be improved.

  According to the present invention, a polycarbonate resin composition having excellent mechanical properties, particularly tensile strength, can be provided by including polypropylene carbonate and cellulose fibers at a specific ratio.

Claims (5)

  The aliphatic polycarbonate resin composition which contains a cellulose fiber in the ratio of 0.1-50 mass parts with respect to 100 mass parts of aliphatic polycarbonate resin.   The aliphatic polycarbonate resin composition according to claim 1, wherein the aliphatic polycarbonate resin is obtained by polymerizing carbon dioxide and alkylene oxide in the presence of a metal catalyst.   The aliphatic polycarbonate resin composition according to claim 1, wherein the aliphatic polycarbonate resin is a polypropylene carbonate resin.   The aliphatic polycarbonate resin composition according to claim 1, wherein the cellulose fiber has a fiber diameter of 10 nm to 500 µm and an aspect ratio (fiber length / fiber diameter) of 20 to 10,000.   The aliphatic polycarbonate resin composition according to claim 1, which has a tensile strength of 25 MPa or more.