JP6591860B2 - Polyolefin resin composition - Google Patents

Description

  The present invention relates to a polyolefin resin composition filled with a filler.

  Polyolefin resin, represented by polypropylene resin, is used as a material for the manufacture of exterior and interior materials for automobiles, exterior materials for household appliances such as refrigerators and washing machines, and various molded products such as trays, shelves and packaging sheets. Widely used. And in order to improve physical properties such as rigidity and impact resistance of the polyolefin resin molded body, it is widely used as a polyolefin resin composition in which a filler (filler) is added to a polyolefin resin as a molding material. Yes. As fillers used for such purposes, fibrous inorganic fillers and non-fibrous inorganic fillers are common.

  In Patent Document 1, there is little mold contamination at the time of molding, it is excellent in antistatic property, stability against light deterioration and molding processability, and has a good balance between high rigidity and impact resistance. In this case, as a polypropylene resin composition capable of obtaining a molded product having excellent flow mark and weld appearance, an inorganic filler (or 99 to 60 parts by mass of a polypropylene polymer and an average particle diameter of 0.01 to 100 μm) (or A polypropylene resin composition containing 1 to 40 parts by mass of an inorganic filler) and 0.05 to 5 parts by mass of a specific hindered amine light stabilizer is described. And it is described that a non-fibrous inorganic filler, a fibrous inorganic filler, or a mixture thereof can be used as the inorganic filler.

  Patent Document 2 discloses a filler containing inorganic fibers made of an inorganic material and spherical silica particles having a volume average particle diameter of 0.01 μm or more and 5 μm or less as a filler composition filled in a resin typified by an epoxy resin. A composition is described. According to this document, the resin composition containing the filler composition is said to be excellent in flow characteristics, and as an example of inorganic fibers, for example, a carbon material having an aspect ratio of 5 or more or a carbon material as a main component is used. And glass and glass-based materials are described.

  Patent Document 3 describes a silica particle material obtained by surface-treating silica particles with a silane coupling agent and an organosilazane as a fine silica particle material having excellent affinity for resin and aggregation suppression effect. Yes.

JP 2009-167407 A Japanese Patent Laid-Open No. 2015-13978 JP 2011-213514 A

One of the recent improvement themes of automobiles is to reduce the weight of the vehicle body for the purpose of saving fuel. For example, in an exterior material such as an automobile bumper, it has been studied to reduce the thickness in order to reduce the weight. However, in the bumper of an automobile, even when the thickness is reduced, it is not easily deformed due to high impact resistance and the action of external force so as not to be easily damaged by an impact caused by contact with another automobile or various objects. High rigidity is required. However, in the polypropylene resin composition that is widely used as a material for automobile bumpers, the impact resistance and rigidity of the molded product are generally in a trade-off relationship.
It is known that the other physical property tends to be low.

  The inventor of the present invention studied the use of fillers described in Patent Documents 1, 2, and 3 as polyolefin resin fillers. As a result, when a thin molded article is produced using a polyolefin resin composition to which fillers described in those documents are added, it exhibits high impact resistance as required in automobile bumpers. It has been found that it is difficult to produce a molded body without sacrificing rigidity.

  Based on the above knowledge, the inventor of the present invention has a polyolefin resin composition that is a molded body of a polyolefin resin such as a polypropylene resin, and that can produce a resin molded body having both high rigidity and high impact resistance. We conducted earnest research to obtain things.

  As a result of the above research, the inventor of the present invention contains polyolefin resin and fibrous basic magnesium sulfate particles in an amount in the range of 99: 1 to 50:50 by mass ratio, and the average particle size is 0.00. Fine non-fibrous inorganic fine particles in the range of 001 to 0.5 μm in an amount in the range of 0.001 to 50 parts by mass and / or 100 parts by mass of resin with respect to 100 parts by mass of fibrous basic magnesium sulfate particles. On the other hand, a polyolefin resin composition molded body produced using a composition containing 0.0002 to 10 parts by mass of the impact resistance index without lowering the flexural modulus as an index of rigidity. It was found that the Izod impact strength was significantly improved, and the present invention was completed.

  Therefore, the present invention includes polyolefin resin and fibrous basic magnesium sulfate particles in an amount ranging from 99: 1 to 50:50 by mass ratio, and further has an average particle diameter of 0.001 to 0.5 μm. The non-fibrous inorganic fine particles in the range are in the range of 0.001 to 50 parts by mass with respect to 100 parts by mass of the fibrous basic magnesium sulfate particles and / or 0.0002 to 10 parts by mass with respect to 100 parts by mass of the resin. The polyolefin resin composition contains in an amount in the range of parts.

  In the polyolefin resin composition of the present invention, as the non-fibrous inorganic fine particles, spherical oxide fine particles are preferable, and spherical silicon dioxide particles are particularly preferable.

  Since the molded body produced using the polyolefin resin composition of the present invention exhibits both high impact resistance and rigidity, it can be advantageously used as an exterior material for automobile bumpers and the like. Moreover, the molded object manufactured using the polyolefin resin composition of this invention can be advantageously used also as automotive interior materials, such as an instrument panel.

  The polyolefin resin composition of the present invention has a mass ratio (the former: the latter) of polyolefin resin and fibrous basic magnesium sulfate particles in the range of 99: 1 to 50:50, preferably 99: 1 to 70:30. Including the amount in the range. In the polyolefin resin composition of the present invention, fine non-fibrous inorganic fine particles having an average particle diameter in the range of 0.001 to 0.5 μm are further added in an amount of 0. 0 to 100 parts by mass of fibrous basic magnesium sulfate particles. It is contained in an amount in the range of 0.0002 to 10 parts by mass as an amount in the range of 001 to 50 parts by mass and / or a content relative to 100 parts by mass of the polyolefin resin. The content of non-fibrous inorganic fine particles with respect to 100 parts by mass of fibrous basic magnesium sulfate particles is preferably in the range of 0.001 to 20 parts by mass, more preferably in the range of 0.001 to 8 parts by mass, The amount is particularly preferably in the range of 0.005 to 3 parts by mass. The content of the non-fibrous inorganic fine particles with respect to 100 parts by mass of the polyolefin resin is preferably in the range of 0.0002 to 3 parts by mass, more preferably in the range of 0.0002 to 1.5 parts by mass, particularly preferably. The amount is in the range of 0.001 to 0.5 parts by mass.

Examples of the polyolefin resin include an ethylene homopolymer, a propylene homopolymer, an ethylene / propylene copolymer, an ethylene / α-olefin copolymer, and a propylene / α-olefin copolymer. be able to. A polyolefin resin may be used individually by 1 type, and may be used in combination of 2 or more type. The polyolefin resin preferably has a melt flow rate (MFR) measured by a method based on ASTM-D1238 (temperature 230 ° C., load 2.16 kg) in the range of 3 to 300 g / 10 minutes.

  Fibrous basic magnesium sulfate particles generally have an average major axis in the range of 5-50 μm, preferably in the range of 10-30 μm, and an average minor axis in the range of generally 0.1-2.0 μm, preferably 0.5- The average aspect ratio (average major axis / average minor axis) is generally 2 or more, preferably 5 or more, and particularly preferably 5 to 50. The average major axis and average minor axis of the fibrous basic magnesium sulfate particles mean the average values of the major axis and minor axis of 1000 particles measured from an enlarged image by a scanning electron microscope (SEM).

  The non-fibrous inorganic fine particles used in the present invention have an average particle size (average particle size of primary particles) in the range of 0.001 to 0.5 μm (1 nm to 500 nm), preferably 0.002 to 0.2 μm (2 nm). ˜200 nm), particularly preferably in the range of 0.005 to 0.1 μm (5 nm to 100 nm). The average particle diameter of the non-fibrous inorganic fine particles is also generally in the range of 1/2 to 1/1000, preferably in the range of 1/2 to 1/500, with respect to the average short diameter of the fibrous basic magnesium sulfate particles. Particularly preferred is a length in the range of 1/5 to 1/500. The average particle diameter of the non-fibrous inorganic fine particles can be measured using, for example, image analysis of a SEM photograph or a particle size distribution measuring apparatus.

  Examples of non-fibrous inorganic fine particles include silicon dioxide particles, magnesium oxide particles, magnesium hydroxide particles, basic magnesium carbonate particles, and calcium carbonate particles. The non-fibrous inorganic fine particles are preferably spherical particles. Here, the spherical particles mean that the average aspect ratio (average major axis / average minor axis) is less than 2, preferably 1.5 or less.

  The non-fibrous inorganic fine particles are preferably spherical silicon dioxide fine particles. The spherical silicon dioxide fine particles may be surface-treated with a silane coupling agent and an organosilazane. Examples of the silane coupling agent include an alkoxysilane having at least one functional group selected from the group consisting of phenyl group, vinyl group, epoxy group, methacryl group, amino group, ureido group, mercapto group, isocyanate group and acrylic group. Can be mentioned. The spherical silicon dioxide particles surface-treated with the silane coupling agent and the organosilazane can be produced by the method described in Patent Document 3 (Japanese Patent Laid-Open No. 2011-213514). The silane coupling agent may be added before or at the time of kneading the filler such as non-fibrous inorganic fine particles and the resin.

  The polyolefin resin composition of the present invention further comprises an antioxidant, an ultraviolet absorber, a pigment, an antistatic agent, a corrosion inhibitor, a flame retardant, a lubricant, a neutralizing agent, a foaming agent, a plasticizer, an anti-bubble agent, and a crosslinking agent. Various additives generally used for improving the physical properties and characteristics of the polyolefin resin composition may be contained.

  The polyolefin resin composition of the present invention can be produced, for example, by a method of melt kneading a raw material mixture containing a polyolefin resin, fibrous basic magnesium sulfate particles, and non-fibrous inorganic fine particles. The raw material mixture is, for example, a method of simultaneously mixing a polyolefin resin, fibrous basic magnesium sulfate particles and non-fibrous inorganic fine particles, or adding non-fibrous inorganic fine particles to a mixture of polyolefin resin and fibrous basic magnesium sulfate particles. It can be prepared using a method, a method of adding fibrous basic magnesium sulfate particles to a mixture of polyolefin resin and non-fibrous inorganic fine particles, and the like. For melt kneading of the raw material mixture, a kneading machine such as a uniaxial melt kneading extruder, a biaxial melt kneading extruder, or a Banbury mixer can be used.

  The polyolefin resin composition of the present invention can be formed into a molded product using any molding method. Examples of molding methods include injection molding methods, extrusion molding methods, calendar molding methods, blow molding methods, foam molding methods and stretch molding methods.

[Example 1]
85 parts by mass of polypropylene resin [MFR (temperature 230 ° C., load 2.16 kg): 52 g / min], fibrous basic magnesium sulfate particles (MOS A-1, manufactured by Ube Materials Co., Ltd., average major axis: 15 μm, 15 parts by mass of average minor axis (0.5 μm) and spherical silica particles (Admanano, manufactured by Admatechs Co., Ltd., average particle diameter: 10 nm, measured by SEM) were mixed at a ratio of 0.0015 parts by mass. The obtained mixture was melted under the conditions of a temperature of 230 ° C. and a shaft rotation speed of 250 rpm using a twin-screw melt kneading extruder (Laboplast Mill Micro, L / D = 18, manufactured by Toyo Seiki Seisakusho Co., Ltd.) The resulting melt-kneaded product was kneaded and extruded into a strand shape, and then cut to obtain a polypropylene resin composition pellet containing fibrous basic magnesium sulfate particles and spherical silica particle pellets.

[Example 2]
A polypropylene resin composition pellet was obtained in the same manner as in Example 1 except that the amount of the spherical silica particles was 0.015 part by mass.

[Example 3]
Polypropylene resin composition pellets were obtained in the same manner as in Example 1 except that the amount of the spherical silica particles was 0.15 parts by mass.

[Example 4]
A polypropylene resin composition pellet was obtained in the same manner as in Example 1 except that the amount of the spherical silica particles was 0.75 parts by mass.

[Example 5]
A polypropylene resin composition pellet was obtained in the same manner as in Example 1 except that the amount of the spherical silica particles was 1.0 part by mass.

[Example 6]
A polypropylene resin composition pellet was obtained in the same manner as in Example 1 except that the amount of the spherical silica particles was 1.5 parts by mass.

[Example 7]
A polypropylene resin composition pellet was obtained in the same manner as in Example 1 except that the amount of the spherical silica particles was 4.5 parts by mass.

[Example 8]
A polypropylene resin composition pellet was obtained in the same manner as in Example 1 except that the amount of the spherical silica particles was 7.5 parts by mass.

[Comparative Example 1]
Polypropylene resin composition pellets were obtained in the same manner as in Example 1 except that the spherical silica particles were not blended.

Polypropylene resin pellets obtained in Examples 1 to 8 and Comparative Example 1, fibrous basic magnesium sulfate particles, blending amount of spherical silica particles, blending ratio of spherical silica particles to 100 parts by mass of polypropylene resin and fibers Table 1 below shows the compounding ratio of the spherical silica particles to 100 parts by mass of the shaped basic magnesium sulfate particles.

Table 1
────────────────────────────────────────
A B C C / A C / B
────────────────────────────────────────
Example 1 85 15 0.0015 0.0018 0.010
Example 2 85 15 0.015 0.018 0.10
Example 3 85 15 0.15 0.18 1.0
Example 4 85 15 0.75 0.88 5.0
Example 5 85 15 1.0 1.2 6.7
Example 6 85 15 1.5 1.8 10
Example 7 85 15 4.5 5.3 30
Example 8 85 15 7.5 8.8 50
────────────────────────────────────────
Comparative Example 1 85 15 0 0 0
──────────────────────────────────────── (Note)
A: Blending amount of polypropylene resin (unit: parts by mass)
B: Blending amount of fibrous basic magnesium sulfate particles (unit: parts by mass)
C: Blending amount of spherical silica particles (unit: parts by mass)
C / A: Compounding ratio of spherical silica particles to 100 parts by mass of polypropylene resin C / B: Compounding ratio of spherical silica particles to 100 parts by mass of fibrous basic magnesium sulfate particles

[Evaluation]
The polypropylene resin composition pellets obtained in Examples 1 to 8 and Comparative Example 1 were injection molded using a small injection molding machine (TE3-1E, manufactured by Nissei Plastic Industry Co., Ltd.) to create a test piece. did. The test piece was a 1BB type (small dumbbell) test piece specified by JIS-K-7162.
Izod impact strength and flexural modulus were measured by the following method using the prepared test piece. The results are shown in Table 2 below together with C / A and C / B described in Table 1 above.

  Izod impact strength: Measured by a method according to JIS-K-7110 using a notching machine (manufactured by Imoto Seisakusho Co., Ltd.).

  Flexural modulus: Measured using a universal testing machine (Strograph VGF, manufactured by Toyo Seiki Seisakusho Co., Ltd.).

Table 2
────────────────────────────────────────
C / A C / B Izod impact strength Flexural modulus
(KJ / m ² ) (GPa)
────────────────────────────────────────
Example 1 0.0018 0.010 5.5 3.9
Example 2 0.018 0.10 6.5 3.5
Example 3 0.18 1.0 6.3 3.7
Example 4 0.88 5.0 5.2 3.6
Example 5 1.2 6.7 5.3 4.0
Example 6 1.8 10 4.8 3.7
Example 7 5.3 30 4.2 3.7
Example 8 8.8 50 3.9 3.7
────────────────────────────────────────
Comparative Example 1 0 0 3.7 3.5
──────────────────────────────────────── (Note)
C / A: Compounding ratio of spherical silica particles to 100 parts by mass of polypropylene resin C / B: Compounding ratio of spherical silica particles to 100 parts by mass of fibrous basic magnesium sulfate particles

  From the results shown in Table 2, molding produced using a polypropylene resin composition (Examples 1 to 8) containing polypropylene resin, fibrous basic magnesium sulfate particles and spherical silica particles as inorganic fine particles within the scope of the present invention. Compared to a molded body produced using a polypropylene resin composition containing only polypropylene resin and fibrous basic magnesium sulfate particles (Comparative Example 1), the body has a flexural modulus equal to or greater than that. It can be seen that the value of Izod impact strength is improved.

Claims (1)

Spherical silicon dioxide containing a polyolefin resin and fibrous basic magnesium sulfate particles in an amount ranging from 99: 1 to 50:50 by mass ratio and having an average particle size in the range of 0.001 to 0.5 μm The particles are included in an amount in the range of 0.001 to 50 parts by mass with respect to 100 parts by mass of the fibrous basic magnesium sulfate particles and / or in an amount in the range of 0.0002 to 10 parts by mass with respect to 100 parts by mass of the resin. Polyolefin resin composition.