JPH1095882A - Polypropylene resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polypropylene resin composition having high rigidity and improved in heretofore insufficient low-temperature impact resistance and having an excellent balance among properties. SOLUTION: This composition comprises 50-95wt.% polypropylene (A), 1-35wt.% ethylene/α-olefin structure elastomer (B) containing 50-100wt.% ethylene/α-olefin copolymer blocks having an α-olefin content of 10-80wt.%, 1-35wt.% polypropylene oxide (C), 3-35wt.% inorganic filler (D) and 0.05-5wt.% acid- modified polypropylene (E) prepared by the addition reaction of propylene with an unsaturated carboxylic acid or an anhydride thereof and 3-50wt.%, in total, based on the resin composition, rubber component of component A, component B and component C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polypropylene resin composition having high rigidity and excellent low-temperature impact resistance and suitable as a material for industrial members.

[0002]

2. Description of the Related Art Conventionally, propylene homopolymers, propylene block copolymers,
Polypropylene-based resin compositions such as propylene random copolymers are known as techniques for improving their impact resistance, such as blend polymers with ethylene-propylene copolymers (JP-A-57-55952) and ethylene-propylene copolymers. Numerous proposals have been made, such as a blend polymer of a copolymer and an ethylene-butene copolymer (JP-A-4-372637). In addition, polyolefin resin [ethylene-
In order to improve the low-temperature impact resistance of [(co) polymer of propylene], a propylene oxide-ethylene oxide block copolymer has been added. (Japanese Patent Laid-Open No. 55-165934)

However, a resin composition comprising a blend polymer of polypropylene and an ethylene-propylene copolymer or a resin composition comprising a blend polymer of polypropylene, an ethylene-propylene copolymer and an ethylene-butene copolymer, Although the rigidity and the impact resistance at room temperature have been improved, they have the disadvantage that the impact resistance at low temperatures below room temperature required for industrial members is low. Further, a resin composition obtained by adding a propylene oxide-ethylene oxide block copolymer to a polypropylene resin has a drawback that sufficient rigidity and low-temperature impact resistance cannot be obtained.

[0004]

DISCLOSURE OF THE INVENTION The present invention has high rigidity and improved low-temperature impact resistance, which has not been able to provide sufficient performance even if there is a need for improvement in the past. The purpose is to develop a polypropylene-based resin composition.

[0005]

According to the present invention, there are provided (1) (A) 50 to 94.95% by weight of polypropylene, and (B) 10 to 80% by weight of α-olefin.
Of ethylene / α-olefin structural elastomer having a content of ethylene / α-olefin copolymer block of 50 to 100% by weight, 1 to 35% by weight, (C) polypropylene oxide of 1 to 35% by weight, and (D) inorganic filler 3 to 35% by weight, (E) 0.05 to 5% by weight of an acid-modified polypropylene obtained by adding 0.01 to 10% by weight of an unsaturated carboxylic acid or an acid anhydride thereof to propylene, and the component (A) (2) (A) polypropylene, (D) an inorganic filler, wherein the rubber component, the component (B), and the component (C) contain a total of 3 to 50% by weight of the resin composition. And (E) a polypropylene-based resin composition according to (1), wherein the remaining resin composition components are blended with a master batch composed of acid-modified polypropylene. Ri was achieve the above purpose.

Hereinafter, the present invention will be described in detail. (A) Polypropylene The polypropylene used in the present invention may be any of propylene homopolymer, block copolymer, and random copolymer, and may be used in combination of two or more of them. . As the comonomer used for the block copolymer and the random copolymer, α-olefins other than propylene such as ethylene, butene-1, pentene-1, and hexene-1 are used, and among them, ethylene is preferable. The propylene content in these copolymers preferably exceeds 80% by weight. In a block copolymer using ethylene as a comonomer, an ethylene-propylene block in the molecule is dispersed in a homopolypropylene block to exhibit rubber elasticity and function as a rubber component. The content of the rubber component is preferably from 10 to 25% by weight of the block polymer.

The polypropylene used in the present invention has a melt flow rate (JIS K-7210, Table 1, condition 1).
4: Test temperature 230 ° C, test load 2.16 kgf / 10
The values measured in minutes are shown. Hereinafter, it is abbreviated as MFR. ) Is 5
It is preferably 100 g / 10 minutes. MFR is 5g
If the time is less than / 10 minutes, the fluidity of the obtained resin composition is inferior and the moldability is deteriorated. When the MFR exceeds 100 g / 10 minutes, the low-temperature impact resistance of the resin composition decreases.

(B) Ethylene / α-olefin structure elastomer The ethylene / α-olefin structure elastomer is an elastomer having an ethylene / α-olefin structure in a molecule, for example, an ethylene / α-olefin copolymer or ethylene / α-olefin copolymer. A block copolymer having an α-olefin structure in a part of the molecule. The ethylene / α-olefin structural elastomer is generally obtained by copolymerizing ethylene and α-olefin monomers.
At this time, propylene, butene-
1, pentene-1, hexene-1, heptene-1, octene-1 and the like. From the viewpoint of ease of production and good physical properties of the obtained material, propylene, butene-1, hexene-1, Octene-1 is preferred.

As another ethylene / α-olefin structural elastomer, a polymer obtained by using a diene such as butadiene or isoprene as a monomer or a copolymer having the polymer block and a polystyrene block is hydrogenated. Also, an elastomer having an ethylene / α-olefin structure in the molecule can be obtained. For example, 1,
Ethylene-ethylene / propylene block copolymer obtained by hydrogenating a copolymer having 4-polybutadiene block and polyisoprene block;
Polybutadiene block and 1,2-polybutadiene /
Ethylene-ethylene / butene block copolymer obtained by hydrogenating a copolymer having a 1,4-polybutadiene block, and styrene obtained by hydrogenating a copolymer having a polystyrene block and a polyisoprene block. Ethylene / propylene block copolymer, polystyrene block and 1,2-polybutadiene /
A styrene-ethylene / butene block copolymer obtained by hydrogenating a polybutadiene block in a copolymer having a 1,4-polybutadiene block can be exemplified.

The ethylene / α- used in the present invention
The olefin structure elastomer has an α-olefin content of 10 to 8 in the ethylene / α-olefin copolymer block.
The ethylene / α-olefin structure of 0 to 50 to 100
It is an ethylene / α-olefin structure elastomer containing by weight. When the α-olefin content in the ethylene / α-olefin copolymer block is less than 10% by weight,
Alternatively, when the content exceeds 80% by weight, the low-temperature impact resistance of the obtained resin composition decreases. Further, the ethylene / α-
When the content of ethylene / α-olefin in the olefin structure elastomer is less than 50% by weight, the low-temperature impact resistance of the obtained resin composition decreases.

The MFR of the ethylene / α-olefin structural elastomer component used in the present invention is as follows:
0.5 to 50 g / 10 min is preferable, and 1 to 30 g / 10 min.
Minutes are particularly preferred. If the MFR is less than 0.5 g / 10 min, or if it exceeds 50 g / 10 min, the low-temperature impact resistance of the obtained resin composition will decrease.

(C) Polypropylene oxide The polypropylene oxide used in the present invention may be a homopolymer of propylene oxide (homopolypropylene oxide), a block copolymer, a random copolymer, or a combination of two or more of these. Can be used. Examples of the comonomer of the block copolymer and the random copolymer include alkylene oxides other than propylene oxide such as ethylene oxide and butene-1 oxide, and epichlorohydrin. As the monomer for crosslinking, an unsaturated epoxide such as allyl glycidyl ether may be used. Further, polypropylene oxide obtained by crosslinking with sulfur or an organic peroxide may be used. Among these, homopolypropylene oxide or a polypropylene oxide-ethylene oxide copolymer having an ethylene oxide content of 50% by weight or less is preferable from the viewpoint of ease of synthesis and physical properties of the obtained resin composition. The MFR of polypropylene oxide is 0.1 to 100 g / 1.
0 minutes is preferable, and 1 to 50 g / 10 minutes is particularly preferable.
When the MFR is less than 0.1 g / 10 minutes, the fluidity of the obtained resin composition is poor, and the moldability is deteriorated. MFR is 100g
If it exceeds / 10 minutes, the low-temperature impact resistance of the obtained resin composition is inferior.

(D) Inorganic Filler As the inorganic filler used in the present invention, those generally used widely in the field of synthetic resins and rubbers can be used. Inorganic compounds which do not react with oxygen or water and which do not decompose during kneading and molding are preferred. Examples of the inorganic filler include metal powders such as aluminum, copper, iron, lead and nickel, and oxides of these metals and metals such as magnesium, calcium, barium, zinc, zirconium, molybdenum, silicon, antimony, and titanium. Examples include compounds such as hydrates (hydroxides), sulfates, carbonates, and silicon salts, double salts thereof, and mixtures thereof. Of these inorganic fillers,
The powdery material preferably has a diameter of 30 μm or less, particularly preferably 10 μm or less. In the case of the acicular powder, the powder having a diameter of 0.1 to 20 μm is preferable, and the powder having a diameter of 0.1 to 15 μm is particularly preferable. Also,
The length is preferably 5 to 200 μm, and 7 to 150 μm.
m are particularly preferred. Furthermore, in the case of a flat plate,
The diameter is preferably 700 μm or less, and 400 μm
The following are particularly preferred. Of these inorganic fillers,
Preferred are talc, mica, wollastonite, potassium whisker titanate, calcium carbonate, magnesium oxysulfate whisker and the like. Moreover, if it is a fibrous filler, its diameter is preferably 2 to 20 μm, and 3 to 15 μm.
μm is particularly preferred. The length is preferably 1 to 12 mm, and glass fibers of 2 to 10 mm are particularly preferable.

(E) Acid-Modified Polypropylene The acid-modified polypropylene used in the present invention is obtained by adding 0.01 to 10% by weight, preferably 0.05 to 8% by weight, of unsaturated carboxylic acid or its anhydride to polypropylene. More preferably, it is obtained by adding 0.1 to 5% by weight. The addition ratio of unsaturated carboxylic acid or its anhydride to polypropylene is 0.01
If the amount is less than 10% by weight, the rigidity of the obtained resin composition is reduced. If the amount exceeds 10% by weight, the effect of the present invention according to the amount used is not recognized, but rather the original polypropylene resin composition is provided. Properties are impaired and rigidity and low-temperature impact resistance are reduced. The polypropylene used here may be any of a propylene homopolymer, a block copolymer, and a random copolymer, and two or more of these may be used in combination. The polypropylene used here may not be the same as the polypropylene used for the component (A).

Examples of the unsaturated carboxylic acids used herein include monocarboxylic acids such as acrylic acid, crotonic acid and cinnamic acid, and dicarboxylic acids such as maleic acid and fumaric acid. Examples of the acid anhydride include maleic anhydride. Among them, maleic acid and maleic anhydride are preferred. The acid-modified polypropylene of the present invention can be produced by treating (heating) polypropylene and an unsaturated carboxylic acid or an acid anhydride thereof in the above mixing ratio. At this time, the polypropylene and the unsaturated carboxylic acid or its anhydride are previously mixed by dry blending, and the resulting mixture is mixed while being melted using a mixing group such as an open roll, an extruder, a kneader or a Banbury, and a pelletizer. It is particularly preferred to produce pellets using In the case of melt mixing, if carried out at a high temperature, the polypropylene will thermally decompose and deteriorate, so generally at 150 to 350 ° C.
It is preferably carried out at 170 to 300 ° C. When the acid-modified polypropylene is melt-mixed, an organic peroxide or a stabilizer against heat, oxygen, and light of the polypropylene may be added as necessary to promote radical generation.

When the acid-modified polypropylene is not used in the polypropylene resin composition, the affinity between (C) polypropylene oxide and (D) the inorganic filler is high, so that these are kneaded to form a resin composition. In this case, an inorganic filler is incorporated into the polypropylene oxide to form an aggregated structure. The inorganic filler incorporated in the polypropylene oxide in this way acts not as an inorganic filler component but as a rubber component. That is, since the intrinsic action of the inorganic filler is reduced, the resulting resin composition has a high low-temperature impact resistance, but significantly reduces the rigidity. Acid-modified polypropylene is present at the interface between polypropylene and the inorganic filler, and by dispersing a large amount of the inorganic filler in the polypropylene, the rigidity is reduced by suppressing the tendency of the inorganic filler to be incorporated into the polypropylene oxide. It has been found that the low-temperature impact resistance can be improved without any problem, and the present invention has been achieved.

(Composition ratio) The proportion of (A) polypropylene in the polypropylene resin composition of the present invention is 50%.
~ 94.95% by weight. The proportion of polypropylene is 5
If it is less than 0% by weight, the rigidity decreases, and if it exceeds 94.95% by weight, the low-temperature impact resistance decreases. In addition, (B) ethylene / α- occupied in the polypropylene resin composition of the present invention.
The proportion of the olefin structure elastomer is 1 to 35% by weight, preferably 2 to 20% by weight. When the composition ratio of the ethylene / α-olefin structure elastomer in the resin composition is less than 1% by weight, the low-temperature impact resistance of the obtained polypropylene-based resin composition decreases, and when it exceeds 35% by weight, the rigidity decreases. The proportion of (C) polypropylene oxide in the polypropylene resin composition of the present invention is 1 to 35% by weight, preferably 2 to 20% by weight. When the composition ratio of polypropylene oxide in the resin composition is less than 1% by weight, the resulting polypropylene resin composition has low impact resistance at low temperature, and when it exceeds 35% by weight, the rigidity decreases.

The proportion of the inorganic filler (D) in the polypropylene resin composition of the present invention is 3 to 35% by weight.
And preferably 5 to 30% by weight. When the composition ratio of the inorganic filler in the resin composition is less than 3% by weight, the rigidity of the polypropylene resin composition obtained is reduced to 35% by weight.
If it exceeds, the low-temperature impact resistance decreases. Further, the proportion of the (E) acid-modified polypropylene in the polypropylene resin composition of the present invention is 0.05 to 5% by weight, and 0.1 to 5% by weight.
~ 3% by weight is preferred. When the composition ratio of the acid-modified polypropylene in the resin composition is less than 0.05% by weight,
The rigidity of the resulting polypropylene resin decreases, and
If the amount is more than 10% by weight, the low-temperature impact resistance decreases. Also,
The total amount of the rubber component, the component (B), and the component (C) in the component (A) (hereinafter, also referred to as a total rubber component) is 3 to 50% by weight of the entire resin composition. I do. When the content of all rubber components with respect to the entire propylene-based resin composition is less than 3% by weight, the low-temperature impact resistance of the obtained propylene-based resin composition decreases, and when it exceeds 50% by weight, the rigidity decreases.

(Production method of polypropylene-based resin composition) The polypropylene-based resin composition of the present invention includes a stabilizer, a lubricant, a charge, and a heat, oxygen, and light widely used in the field of synthetic resins and synthetic rubbers. Inhibitors, flame retardants,
It is free to mix a colorant and a plasticizer. Further, depending on the case, polyethylene or poly 4-
Methyl-1 pentene, polystyrene, polybutadiene or polyisoprene styrene graft polymer, polyester, polyamide, high molecular polymer such as polycarbonate, etc., when producing a polypropylene resin composition according to the purpose of use, or molded products You may add at the time of manufacture. The purpose of the polypropylene resin composition of the present invention can be achieved by uniformly blending the components (A), (B), (C), (D) and (E) and additives. . The method of mixing (mixing method) is not particularly limited, and a method generally used in the field of synthetic resins may be applied.

As a mixing method, a method of dry blending using a generally used mixer such as a Henschel mixer, a tumbler and a ribbon mixer, and a method using a mixer such as an open roll, an extrusion mixer, a kneader and a Banbury are used. There is a method of mixing while melting. Of these methods, two or more of these mixing methods may be used in combination to obtain a more uniform resin composition (for example, after dry-blending in advance, the mixture is melt-mixed). Even when dry blending is used in combination, or when using one or two or more melt mixing methods, in producing molded products by various molding methods, pelletizing using a pelletizer may be used. Particularly preferred. Of the above mixing methods, both in the case of melt-mixing and in the case of molding by a molding method described later, it must be carried out at a temperature at which the resin used is melted. However, when the reaction is carried out at a high temperature, the raw material resin is thermally decomposed or deteriorated. Therefore, the reaction is generally carried out at 150 to 350 ° C, preferably 170 to 250 ° C.

The polypropylene resin composition of the present invention is formed into a desired shape by applying a molding method such as an injection molding method, an extrusion molding method, a compression molding method, and a hollow molding method which are generally practiced in the field of synthetic resins. can do. Also,
After being formed into a sheet using an extruder, the sheet may be formed into a desired shape by a secondary processing method such as a vacuum forming method or a pressure forming method. In producing the polypropylene resin composition of the present invention, in order to increase the dispersion of the inorganic filler in the polypropylene, kneading the polypropylene, the inorganic filler and the acid-modified polypropylene in advance, to produce a so-called master batch By kneading the master batch and the remaining components containing polypropylene oxide, the amount of the inorganic filler taken into the polypropylene oxide can be suppressed.

[0022]

The present invention will be described below in more detail with reference to examples and comparative examples. In the following examples and comparative examples, each physical property was measured by the following method. (1) As the evaluation of low-temperature impact resistance, the embrittlement temperature (° C.)
It was measured according to IS K-7216. The lower the embrittlement temperature, the higher the low-temperature impact resistance. (2) Flexural modulus (kgf / cm2)
Was measured at a temperature of 23 ° C. according to ASTM D790. (A) used in Examples and Comparative Examples,
The types and physical properties of the components (B), (C), (D) and (E) are as follows.

(A) Polypropylene As the polypropylene, a homo type polypropylene (PP-1) having an MFR of 30 g / 10 minutes and an MFR of 40 g
g / 10 minutes, is a block copolymer using ethylene as a comonomer, and has a rubber component ratio (a ratio of components soluble in heptane when extracted at the boiling point of heptane) of 22.
% By weight of polypropylene (PP-2) was used. (B) Ethylene / α-olefin structure elastomer The following elastomers shown in Table 1 were used as the ethylene / α-olefin structure elastomer. In each case, the structure of the ethylene / α-olefin block is a random structure. Ethylene / propylene copolymer (EPR-1, EPR-
2, EPR-3) Ethylene / butene copolymer (EBR) Ethylene / hexene copolymer (EHR) Ethylene / octene copolymer (EOR) Ethylene-ethylene / propylene diblock copolymer (CEP-1, CEP- 2) Ethylene-ethylene / butene-ethylene triblock copolymer (CEBC-1, CEBC-2), styrene-ethylene / propylene-styrene triblock copolymer (SEPS) Styrene-ethylene / butene-styrene triblock copolymer Coalescing (SEBS)

[0024]

[Table 1]

(C) Polypropylene oxide As the polypropylene oxide, MFR 3 g / 10
Oxide homopolymer (POR-1) and a propylene oxide-ethylene oxide random copolymer (P) composed of 90% by weight of propylene oxide and 10% by weight of ethylene oxide and having an MFR of 5 g / 10 minutes.
OR-2) was used. (D) Inorganic filler As the inorganic filler, talc (average particle size: 2.0 μm), mica (average particle size: 230 μm), whisker (magnesium oxysulfate whisker, average fiber diameter: 0.7 μm, average fiber length: 40 μm) ) Was used. (E) Acid-modified polypropylene As acid-modified polypropylene, MFR is 0.38 g / 1.
0 minutes homotype polypropylene 99.5% by weight, maleic anhydride 0.4% by weight, 2,2′-bis (t-butylperoxyisopropyl) as an organic peroxide
0.1% by weight of benzene was dry-blended in advance using a Henschel mixer for 5 minutes.
Pellets manufactured by mixing using a vented extruder (diameter 40 mm) set at 00 ° C (E-1),
And 98% by weight of homo-type polypropylene having an MFR of 10 g / 10 minutes and 2% by weight of maleic acid were dry-blended in advance using a Henschel mixer for 5 minutes, and the resulting mixture was extruded with a vented extruder (diameter: 200 ° C.). (E-2), which was produced by mixing pellets while mixing by using (40 mm).

(Preparation of test pieces) Table 2 shows the proportions of these components. Regarding the preparation of all test pieces except Comparative Examples 1 to 3, first, (D) an inorganic filler and (E) an acid-modified polypropylene were prepared in advance by the same amount of (A) as the total amount of components (D) and (E). ) Was blended with polypropylene, dry-blended with a Henschel mixer for 5 minutes, and kneaded using a co-axial twin-screw extruder (diameter 30 mm) set at 210 ° C to produce pellets. The pellets and the remaining components were blended so as to have the ratio shown in Table 2, and dry-blended for 5 minutes using a Henschel mixer. Comparative Example 1
The components (A), (B), and (D) were used for the components (A) and (2), and the components (A), (B), and
The components (C) and (D) were simultaneously put into a Herschel mixer, respectively, and dry-blended for 5 minutes. The obtained mixture was kneaded using a co-rotating twin-screw extruder (diameter 30 mm) set at 210 ° C. to produce pellets. The pellets were subjected to injection molding using an injection molding machine set at 230 ° C. to produce test specimens for measurement. Table 2 shows the measurement results of the brittle temperature and the flexural modulus of each test piece.

Example 1 (A) Component PP-1, (B)
Component EPR-1, component (C) component POR-1, component (D) component talc and component (E) component acid-modified polypropylene were added in proportions of 60% by weight, 10% by weight, 10% by weight, 19% by weight and 1% by weight, respectively. Table 2 shows the resin composition obtained by blending
As shown in the figure, both the low-temperature impact resistance and the rigidity were high. (Comparative Examples 1 and 2) Comparative Examples 1 and 2 are a combination of a polypropylene and an ethylene-propylene copolymer known as a prior art, and a polypropylene, an ethylene-propylene copolymer and an ethylene-butene copolymer. The resin composition was obtained in combination and had low low-temperature impact resistance as shown in Table 2.

(Examples 2 to 17) (A), (B),
Each of the resin compositions obtained by changing the type and composition ratio of each component of (C), (D) and (E) as shown in Table 2 had high low-temperature impact resistance and rigidity. (Comparative Example 3) When the component (E) was not added, the rigidity of the obtained resin composition was low. (Comparative Examples 4 to 6) When the structure of the component (B) was out of the range of the present invention, the low-temperature impact resistance of the obtained resin composition was low.

[0029]

[Table 2]

[0030]

The polypropylene resin composition of the present invention has the following effects. (1) High rigidity. (2) Excellent low-temperature impact resistance. The polypropylene-based resin composition of the present invention exhibits the above-described effects, and is therefore suitable as a material for industrial members.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08L 71:02 23:26) (C08K 13/04 3:34 7:08)

Claims (2)

[Claims] (A) Polypropylene 50 to 94.9
5% by weight, the content of (B) α-olefin is from 10 to 80
Ethylene / α-olefin having an ethylene / α-olefin copolymer block content of 50 to 100% by weight.
Olefin structure elastomer 1-35% by weight, (C)
Polypropylene oxide: 1 to 35% by weight, (D) inorganic filler: 3 to 35% by weight, (E) propylene: 0.01 to 10% by weight of unsaturated carboxylic acid or anhydride thereof
The acid-modified polypropylene added is composed of 0.05 to 5% by weight, and the total of the rubber component, the component (B) and the component (C) in the component (A) is 3 to 50% by weight in the resin composition.
A polypropylene-based resin composition characterized by containing: 2. A masterbatch comprising (A) polypropylene, (D) an inorganic filler and (E) an acid-modified polypropylene, wherein the remaining resin composition components are blended.
The polypropylene-based resin composition as described in the above.