JP2016044204A - Polypropylene resin composition comprising polypropylene carbonate and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition having excellent mechanical properties such as ductility and impact resistance, and also having environmental compatibility.SOLUTION: A resin composition comprises (A) polypropylene carbonate with a weight average molecular weight of 10,000-1000,000, (B) polypropylene with an MFR of 0.1-60 measured by JIS K7210, and (C) an epoxy group-containing ethylene copolymer, where the component (B) is a continuous phase, and the components (A) and (C) are a dispersion phase with a number average particle diameter of less than 2 μm.SELECTED DRAWING: None

Description

  The present invention relates to a polypropylene resin composition containing polypropylene carbonate and a method for producing the same.

  In recent years, the need for an environmentally compatible resin has been greatly increased in order to improve the global environment. In particular, the carbon dioxide emission problem is an important issue that must be resolved urgently. Polypropylene carbonate (PPC) is known as an inexpensive resin using carbon dioxide as a raw material, and if PPC can be applied in a wide range, it is very preferable in terms of the global environment. However, PPC has a problem that heat resistance and mechanical properties are insufficient.

  So far, resin compositions using polypropylene carbonate have been reported. For example, Patent Document 1 discloses a composition of polypropylene carbonate and modified polypropylene, and Patent Document 2 discloses a composition containing polypropylene carbonate and polyacrylate. However, these documents do not disclose including an epoxy group-containing polymer as a third component. Patent Document 3 discloses a composition containing polypropylene carbonate, polyester, and an epoxy group-containing polymer. Patent Document 4 discloses a composition containing polypropylene carbonate, polyethylene, and an epoxy group-containing polymer (Example), but only describes the thin-wall moldability, and does not mention its structure or physical properties at all. . Therefore, the interface structure between polypropylene carbonate and polyolefin is not clarified.

JP 2010-138326 A International Publication No. 2010/053110 Special table 2012-504166 gazette JP 2012-241047 A

S. Inoue, H. Koinuma, and T. Tsuruta, J. Polym. Sci., Polym. Lett., Ed., 7, 287 (1969). S. Inoue, H. Koinuma, and T. Tsuruta, Makromol. Chem., 130, 210 (1969). 4th Annual European Rheology Conference, Italy, 2007.Rheol Acta DoI10.1007

  As described above, a resin composition containing polypropylene carbonate has been proposed, but mechanical properties such as ductility and impact resistance have not been sufficient. In view of the above circumstances, an object of the present invention is to provide an environmentally compatible resin composition that is excellent in mechanical properties such as ductility and impact resistance.

The present inventors have found that the above problems can be solved by a resin composition containing polypropylene carbonate and polypropylene and an epoxy group-containing ethylene copolymer as a compatibilizing agent thereof, and have completed the present invention. That is, the said subject is solved by the following this invention.
(1) (A) polypropylene carbonate having a weight average molecular weight of 10,000 to 1,000,000,
(B) including polypropylene having an MFR measured by JIS K7210 of 0.1 to 60, and (C) an epoxy group-containing ethylene copolymer,
The resin composition in which the component (B) is a continuous phase and the components (A) and (C) are dispersed phases having a number average particle diameter of less than 2 μm.
(2) The resin composition as described in (1) whose content of the said component (C) is 1-30 mass parts with respect to a total of 100 mass parts of a component (A) and (B).
(3) The resin composition as described in (1) or (2) whose mass ratio (A) / (B) of the said component is 3-60 / 97-40.
(4) The composition according to any one of (1) to (3), which is obtained by a production method including melt-kneading the components (A) to (C) at a shear rate of 20 to 1000 (s ⁻¹ ). Resin composition.
(5) A molded article comprising the resin composition according to any one of (1) to (4).
(6) An injection molded article, an extruded molded article, a tubular molded article, a sheet / film molded article, or a fiber comprising the resin composition according to any one of (1) to (4).
(7) Household electrical products, electrical / electronic parts, communication equipment parts, or automobile parts using the molded article according to (5) or (6).
(8) The method for producing a resin composition according to (1), comprising melt-kneading the components (A) to (C) at a shear rate of 20 to 1000 (s ⁻¹ ).

  According to the present invention, an environmentally compatible resin composition having excellent mechanical properties such as ductility and impact resistance can be provided.

  Hereinafter, the present invention will be described in detail. In this specification, X to Y include values at both ends thereof, that is, X and Y.

1. Resin Composition of the Present Invention The resin composition of the present invention contains polypropylene carbonate as the component (A), polypropylene as the component (B), and an epoxy group-containing ethylene copolymer as the component (C).

(1) Component A
Polypropylene carbonate is a polymer having a repeating unit represented by the following general formula (1).

Wherein, ^{R 1} represents a hydrogen atom, a carbon number of 1 to 4 alkyl groups. In view of easy availability, R ¹ is preferably a methyl group.

  Polypropylene carbonate can generally be produced from carbon dioxide and an epoxy compound. Specifically, an aliphatic polycarbonate (APC) can be obtained by alternately copolymerizing carbon dioxide and an epoxy compound in the presence of a catalyst. The method for producing polypropylene carbonate is described in Non-Patent Documents 1 and 2, for example. The weight average molecular weight of polypropylene carbonate is 10,000 to 1,000,000. The lower limit is preferably 50,000 or more, more preferably 100,000 or more. When the weight average molecular weight is less than the lower limit, mechanical properties such as strength and elastic modulus tend to be insufficient. Moreover, when a weight average molecular weight exceeds the said upper limit, moldability will fall.

(2) Component B
Polypropylene is a polymer of propylene, and in the present invention, it includes copolymers with other monomers. Examples of the polypropylene of the present invention include homopolypropylene, a block copolymer of propylene and ethylene or an α-olefin having 4 to 10 carbon atoms (also referred to as “block polypropylene”), propylene and ethylene or a carbon number of 4 to 10 Random copolymers with α-olefins (also referred to as “random polypropylene”) are included. The combination of “block polypropylene” and “random polypropylene” is also referred to as “polypropylene copolymer”.

  As the polypropylene, one or more of the homopolypropylene, block polypropylene, and random polypropylene may be used. Among these, homopolypropylene and block polypropylene are preferable as the polypropylene of the present invention.

  Examples of the α-olefin having 4 to 10 carbon atoms used for the polypropylene copolymer include 1-butene, 1-pentene, isobutylene, 3-methyl-1-butene, 1-hexene, and 3,4-dimethyl-1. -Butene, 1-heptene, 3-methyl-1-hexene are included. The content of the α-olefin is preferably 20% by mass or less in the total monomers. The content of ethylene in the polypropylene copolymer is preferably 5% by mass or less in all monomers.

  The polypropylene copolymer is preferably a random copolymer of propylene and ethylene or a block copolymer of propylene and 1-butene, and particularly preferably a random copolymer of propylene and ethylene.

  The melt flow rate (230 ° C., 2.16 kg, 10 minutes) of polypropylene is 0.1 to 60 g, preferably 1 to 30 g. Although it is also called the melt flow rate (MFR) of polypropylene, the physical properties of the resin composition may be insufficient if it is outside the above range. MFR is measured according to JIS K7210.

(3) Component C
The epoxy group-containing ethylene copolymer is an ethylene-based binary copolymer or an ethylene-based terpolymer that contains an epoxy group. The ethylene-based binary copolymer is a copolymer comprising (a) an ethylene unit, (b) an ethylenically unsaturated carboxylic acid glycidyl ester unit or an ethylenically unsaturated hydrocarbon group glycidyl ether unit. The ethylene terpolymer includes (a) an ethylene unit, (b) an ethylenically unsaturated carboxylic acid glycidyl ester unit or an ethylenically unsaturated hydrocarbon group glycidyl ether unit, and (c) a vinyl acetate unit or acrylic acid. A copolymer consisting of methyl units. The ethylene unit refers to a portion derived from ethylene in the copolymer, and specifically refers to a unit represented by — (CH ₂ —CH ₂ ) —. Ethylenically unsaturated carboxylic acid glycidyl ester units and the like are defined similarly.

  The composition of the copolymer is, in the case of an ethylene-based binary copolymer, the unit (a): (b) is preferably 95 to 40% by mass: 5 to 60% by mass, and 90 to 50% by mass: 10-50 mass% is preferable. The composition of the ethylene-based terpolymer is preferably (a) unit: (b) unit: (c) 40-94 mass%: 1-20 mass%: 5-40 mass%, preferably 50-90 mass%. %: 2 to 15% by mass: 8 to 35% by mass is preferable. In the ethylene-based terpolymer, the compounds giving (b) an ethylenically unsaturated carboxylic acid glycidyl ester unit or an ethylenically unsaturated hydrocarbon group glycidyl ether unit are represented by the following general formulas (2) and (3), respectively. The

  In General formula (2), R is a C2-C13 hydrocarbon group which has one ethylene bond. The carbon number of R is preferably 2-10. Examples of the ethylenically unsaturated carboxylic acid glycidyl ester unit represented by the general formula (2) include glycidyl α, β-unsaturated carboxylic acid such as glycidyl acrylate, glycidyl methacrylate, and diglycidyl itaconate.

In general formula (3), R is defined similarly to formula (2). X is —CH ₂ —O— or a group represented by the following chemical formula (3-1).

  Here, the MFR of the epoxy group-containing ethylene copolymer is preferably 0.01 to 50 g / 10 minutes, more preferably 0.05 to 30 g / 10 minutes. MFR is measured under the conditions of a resin temperature of 230 ° C. and a measurement load of 21 N (2.16 kg · f) in accordance with the method defined in JIS K7210. When this MFR is less than 0.01 g / 10 minutes or exceeds 50 g / 10 minutes, the physical properties of the resulting resin composition may be lowered, or the moldability may be lowered.

(4) Composition ratio The composition ratio of each component is determined so that the component (B) is a continuous phase and the components (A) and (C) are dispersed phases. When component (B) is a continuous phase, a resin composition having low cost and excellent performance is obtained. 3-60 / 97-40 are preferable and, as for mass ratio of a component (A) and a component (B), 6-52 / 94-47 are more preferable. Moreover, 1-30 mass parts is preferable, as for the quantity of the component (C) with respect to 100 mass parts of total amounts of a component (A) and a component (B), 2-25 mass parts is more preferable, and 4-20 mass parts is further. preferable.

(5) Other components An electrical conductivity-imparting substance can be further added to the resin composition of the present invention to obtain an electrically conductive resin composition. The resin composition of the present invention may further include other compounding agents depending on applications and purposes, for example, electrical conductivity imparting substances such as carbon black, carbon fiber, graphite, metal fiber, carbon nanotube, and metal oxide, Anti-plasticizers such as inorganic fillers such as talc, mica, calcium carbonate, wollastonite, glass fibers, coupling agents, reinforcing agents, flame retardant aids, stabilizers, pigments, mold release agents, or elastomers An impact modifier or the like can be blended. The compounding quantity of these compounding agents is 60 mass parts or less with respect to a total of 100 mass parts of component (A), (B) and (C), Preferably it is 40 mass parts or less.

(6) Structure of Resin Composition of the Present Invention In the resin composition of the present invention, component (B) polypropylene forms a continuous phase, and components (A) and (C) form a dispersed phase. The epoxy group-containing ethylene copolymer of component (C) is mainly present at the interface between components (A) and (B), but may also be present in component (A) or component (B). (A) The number average particle diameter of the phase particles is 2 μm or less, and more preferably 1.5 μm or less. When the number average particle diameter is out of the above range, the mechanical properties of the obtained resin composition are significantly lowered. The phase structure can be observed with a scanning electron microscope image or a transmission electron microscope image. The number average particle diameter of the particles is preferably determined from these microscopic images. The number average particle diameter of the (C) phase particles is also 2 μm or less, but is preferably smaller than the (A) phase particles.

  In the present invention, since the component (B) polypropylene is a continuous phase, it is inexpensive, and since the component (A) polypropylene carbonate is finely dispersed with an appropriate particle size, it exhibits excellent mechanical properties. Moreover, since polypropylene carbonate uses carbon dioxide as a raw material, the resin composition of the present invention also has environmental compatibility.

2. Production method of resin composition of the present invention The resin composition of the present invention can be obtained by melt-kneading components (A), (B) and (C). For melt kneading, a kneading machine such as a batch type twin screw kneader, a single screw extruder, a twin screw extruder, or a four screw extruder can be used. The method of melt kneading is not particularly limited. For example, the components (A) to (C) may be obtained by melting and kneading all together, or the components (A) and (C) are fed to the front stage of the extruder, and the components (B ) Can be fed and melt-kneaded. In the present invention, in order to avoid thermal decomposition of the components, it is also preferable to use a conical extruder or a single screw extruder that does not have a strong kneading segment. The melt kneading temperature is preferably 130 to 230 ° C, more preferably 160 to 210 ° C. The kneading is preferably performed in a short time so as not to cause thermal decomposition. Specifically, it is preferably performed for 0.5 to 5 minutes, more preferably 0.5 to 2 minutes.

In the present invention, it is important to set the range of the shear rate in the melt kneading of the components (A) to (C). If the shear rate is too high, component (A) may be easily decomposed. Shear rate in the melt-kneading is preferably from 20 to 1000 ^{(s -1),} more preferably ^{40~800 (s -1), 70~500 (} s -1) is more preferred. When the shear rate is out of the above range, the component (A) may be decomposed or a dispersion failure may occur, which is not preferable.

Regarding a biaxial conical, co-rotating screw type kneader (manufactured by Thermo Scientific Haake, Haake Minila) that can be used in the present invention, the shear rate (γ) is determined as follows (Non-patent Document 3) .
γ = DΩ / 2h
D is the average screw diameter, h is the average gap between the screw and the barrel, Ω = 2πN / 60 is the angular velocity, and N is the number of screw revolutions per minute. D is preferably 10 mm and h is preferably 0.5 mm.

3. Processing method and application of the resin composition of the present invention The resin composition of the present invention is easily processed into a molded product by a processing method used for ordinary thermoplastic resin molded products. Examples of processing methods include injection molding, extrusion molding, film / sheet molding, fiber molding, vacuum molding, blow molding, press molding, calendar molding, foam molding, and the like. In this case, the resin composition of the present invention can be used as an injection molded article, an extruded molded article, a tubular molded article, a sheet / film molded article, or a fiber. In addition, since the resin composition of the present invention is excellent in heat resistance, impact resistance, ductility and the like and has environmental compatibility, films and sheets for electric / electronic parts, communication parts, packaging, fibers, automobiles, etc. It can be widely applied to household appliances such as parts, refrigerators, and televisions.

(1) Physical property test Tensile test: A strip-shaped test piece was used, using a Strograph VES 50 type manufactured by Toyo Seiki Seisakusho Co., Ltd., with a load cell of 1 kN, a distance between chucks of 40 mm, and a stretching speed of 10 mm / min.
Tensile impact test: DG digital impact tester manufactured by Toyo Seiki Seisakusho Co., Ltd., load 4J due to the mass of the hammer, distance from the center of rotation of the hammer to the center of gravity 0.23 mm, hammer lifting angle 150 °, period 0. The test was conducted in accordance with JIS 7160 at 962 sec and at a temperature of 20 ° C.
SEM observation: The strand extruded by a kneader was immersed in liquid nitrogen for about 5 minutes, then quickly taken out and broken, and the fracture was gold-deposited and then observed.

(2) Component of resin composition a-1: Polypropylene carbonate The polymer has a structure in which R ¹ is a methyl group in the formula (1).
Number average molecular weight 8.2 × 10 ⁴ (THF solvent, GPC)
Weight average molecular weight 3.9 × 10 ⁵ (THF solvent, GPC)

b-1: Polypropylene Prime Polymer Co., Ltd. homopolypropylene (grade: E-200GP)
MFR = 2.0g / 10min (JIS K7210)
Density 0.9 g / cm ³

c-1: Epoxy group-containing ethylene copolymer Bondfast 7L manufactured by Sumitomo Chemical Co., Ltd.
MFR (190 ° C., 2.16 kg load) = 7 g / 10 min
Melting point 60 ° C
Surface hardness (ASTM D2240, Shore D) 18
Ethylene / glycidyl methacrylate / methyl acrylate = 70/27/3 (weight ratio)

e-1: Graft copolymer MODIFER A4100 manufactured by NOF Corporation
Graft copolymer in which a styrene segment is grafted to a segment composed of ethylene unit / ethylenically unsaturated carboxylic acid glycidyl ester (EGMA) unit (segment ratio is 70/30 (mass ratio))
Glycidyl methacrylate content in EGMA 15% by mass,
Melting point 95 ° C
Glass transition temperature -28 ° C

[Examples 1-3] and [Comparative Examples 1-4]
Component (A) was used after preliminary drying at 120 ° C. for 4 hours using a hot air dryer in advance.
A predetermined amount of each component having the composition shown in Table 1 was thoroughly dry blended at room temperature. This dry blend was melt-kneaded using a biaxial conical kneader (Haake MiniLab, manufactured by Thermo Scientific) equipped with a co-rotating screw. The melt kneading temperature was 200 ° C., and the screw rotation speed was 40 rpm. The sample was melt-kneaded at 1 pass in a kneading apparatus, and then extruded from the apparatus into a strand shape. According to the above shear rate equation, the shear rate in this example was about 42 (s ⁻¹ ).

  The strand was cut with a cutter into pellets to obtain the resin composition of the present invention. Next, the obtained pellet was pressed at 190 ° C. and 10 MPa for 2 minutes using a press molding machine, and then rapidly cooled to prepare a press sheet. The press sheet was subjected to physical property measurement. The results are shown in Table 1.

For the strand fracture surface obtained in Example 1, the average diameter of the dispersed phase measured for 20 particles was about 0.82 μm. Further, the tensile impact strength of the resin composition obtained in Example 1 was 39.5 kJ / m ² , but in Comparative Example 1, the tensile impact strength was not measurable because the test piece was brittle. The tensile impact strength in Comparative Example 2 was 25.8 kJ / m ² .

  As described above, the present invention can provide a resin composition that is excellent in mechanical properties such as ductility and impact resistance, is inexpensive, and is environmentally compatible.

Claims (8)

(A) polypropylene carbonate having a weight average molecular weight of 10,000 to 1,000,000,
(B) including polypropylene having an MFR measured by JIS K7210 of 0.1 to 60, and (C) an epoxy group-containing ethylene copolymer,
The resin composition in which the component (B) is a continuous phase and the components (A) and (C) are dispersed phases having a number average particle diameter of less than 2 μm.   The resin composition according to claim 1, wherein the content of the component (C) is 1 to 30 parts by mass with respect to 100 parts by mass in total of the components (A) and (B).   The resin composition of Claim 1 or 2 whose mass ratio (A) / (B) of the said component is 3-60 / 97-40. The resin composition in any one of Claims 1-3 obtained by the manufacturing method including melt-kneading the said components (A)-(C) with the shear rate of 20-1000 (s < ^-1 >).   The molded object containing the resin composition in any one of Claims 1-4.   An injection molded body, an extrusion molded body, a tubular molded body, a sheet / film molded body, or a fiber comprising the resin composition according to any one of claims 1 to 4.   A household electric product, an electric / electronic component, a communication device component, or an automobile component using the molded article according to claim 5 or 6. The manufacturing method of the resin composition of Claim 1 including melt-kneading the said component (A)-(C) with the shear rate of 20-1000 (s < ^-1 >).