JPH10273569A - Polypropylene resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the crystallization rate of polypropylene to higher than obtd. by the nucleation effect of talc to thereby provide a polypropylene resin compsn. which gives a molded item having a high rigidity, while hardly exhibiting the decrease in impact strength, and excellent in the balance among physical properties by adding a partial metal salt of rosin acid to a compsn. comprising an isotactic polypropylene and/or an ethylene-propylene block copolymer, a thermoplastic rubber, and talc. SOLUTION: This compsn. comprises 30-94 pts.wt. isotactic polypropylene and/or ethylene-propylene block copolymer (A), 5-40 pts.wt. rubber component (C) 1-30 pts.wt. talc (C), and a nucleating agent mainly comprising a particle metal salt of rosin acid (D) in an amt. of 0.01-5 wt.% of ingredient A, the sum of ingredients A, B, and C being 100 pts.wt.

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, and more particularly, to an isotactic resin composition.
The present invention relates to a polypropylene resin composition comprising a polypropylene and / or an ethylene / propylene block copolymer, a rubber component and a partial metal salt of rosin acid which is a nucleating agent for talc and polypropylene. The polypropylene-based resin composition of the present invention has excellent impact resistance and rigidity, and is useful as a structure for automobile parts and the like.

[0002]

2. Description of the Related Art Isotactic polypropylene has excellent workability, chemical resistance and mechanical properties and is used for various purposes. However, depending on the application, rigidity,
In some cases, impact resistance was not sufficient.

In order to improve the impact resistance of polypropylene, blending of a thermoplastic rubber or an ethylene / propylene block copolymer is known as a known technique (JP-A-4-372637, JP-A-4-372637). -1
09316 and JP-A-8-41259). In this method, the effect of improving the impact resistance of polypropylene can be obtained by adding these components, but on the other hand, the rigidity cannot be denied. On the other hand, in order to improve the rigidity of polypropylene whose rigidity has been reduced by blending a rubber or an ethylene / propylene block copolymer, there is also a proposal to add talc powder which is an inorganic substance (JP-A-4-153243 and JP-A-4-153243). 8
-41277 and the like). In this proposal, it is possible to improve the rigidity to some extent, but there is a limit to the amount of talc added, and it becomes brittle with the addition of excessive talc, which results in impairing the impact resistance of the obtained composition. Therefore, this method has its limitations.

[0004] In order to improve the rigidity of the molded article comprising the polypropylene and / or ethylene / propylene block copolymer, the thermoplastic rubber component and the talc powder while maintaining the impact resistance, it is necessary to perform
It has been found that the crystallization speed of polypropylene should be increased to produce fine crystals. However, talc, in addition to its role as an inorganic filler to improve rigidity,
It also has the properties of polypropylene as a crystal nucleating agent. Therefore, even if a conventional nucleating agent is added to increase the crystallization speed of polypropylene (see Japanese Patent Application Laid-Open No. 2-69237), the crystallization nucleating agent effect of talc is hidden and the crystallization speed does not increase. Fine crystals could not be produced.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to remedy the above-mentioned drawbacks in the prior art in a polypropylene resin composition, and to make use of isotactic polypropylene containing talc and / or ethylene.・ By adding a partial metal salt of rosin acid to a composition consisting of a propylene block copolymer and a thermoplastic rubber, the crystallization speed of polypropylene is improved more than the nucleating agent effect of talc, and as a result, the rubber addition effect Another object of the present invention is to provide a polypropylene-based resin composition having improved rigidity without lowering impact resistance.

[0006]

Means for Solving the Problems Accordingly, the present inventors have:
In order to solve the above problems, intensive research has been conducted on a polypropylene resin composition comprising isotactic polypropylene and / or an ethylene / propylene block copolymer, a thermoplastic rubber, talc, and a specific rosin acid partial metal salt. As a result of the repetition, the following findings were obtained, and the present invention was completed.

That is, the polypropylene resin composition obtained in the present invention can start crystallization from a temperature higher than the crystallization temperature of talc-added polypropylene due to the nucleating effect of the rosin acid partial metal salt. In other words, the crystallization rate is increased by the effect of the excellent nucleating agent of the rosin acid partial metal salt, and as a result, the individual crystals in the compact are refined. The reason for this is that, when the crystal nucleus generation rate is low, a large crystal is formed because the crystal collides with the crystal grown from another crystal nucleus and the time until the growth is completed is long. When the crystal nucleus generation rate is high, it can be explained that the crystal formed is miniaturized because the crystal nucleus immediately collides with a crystal grown from another crystal nucleus. When the rosin acid partial metal salt of the present invention is used as a crystal nucleating agent, crystallization starts at a higher temperature than when only talc is used, so that the nucleus generation rate is high and the time until the end of crystallization is short. That is, since a fine crystal structure of polypropylene is formed due to a high crystallization rate, a molded article having excellent mechanical properties while maintaining high impact resistance while having high rigidity can be obtained. Such a polypropylene resin composition is widely used as an industrial product by injection molding, and is suitably used for electric and electronic parts, automobile parts, various parts, and the like.

According to a first aspect of the present invention, there is provided (A) 30 to 94 parts by weight of an isotactic polypropylene and / or an ethylene / propylene block copolymer,
(B) 5 to 40 parts by weight of a rubber component, (C) talc 1 to 30
A nucleating agent containing, as a main component, parts by weight of (D) a partial metal salt of rosin acid and 0.005 parts by weight of the resin component (A)
The present invention relates to a polypropylene resin composition comprising 1 to 5 parts by weight (wherein the components (A), (B) and (C) are 100 parts by weight in total).

A second invention according to claim 2 is as follows.
(D) The polypropylene resin composition according to the first invention, wherein the partial metal salt of rosin acid is at least one partial metal salt selected from the group consisting of natural rosin, modified rosin, and purified products thereof. is there. In a third aspect of the present invention, (D) the partial metal salt of rosin acid is a compound of the formula (1a), (1b), (2a) or (2)
b), (3a) and (3b) (provided that the formulas (1a) to
In (3b), R ₁ , R ₂ and R ₃ each represent a hydrogen atom, an alkyl group, a cycloalkyl group or an aryl group, which may be the same or different. Also, M
₁ , M ₂ and M ₃ are monovalent, divalent and trivalent, respectively.
The present invention relates to the polypropylene resin composition according to the first or second invention, which is at least one kind of partial metal salt represented by one formula selected from the group consisting of:

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The polypropylene resin composition according to the present invention will be described in detail below. The polypropylene resin composition according to the present invention comprises (A) an isotactic polypropylene and / or an ethylene / propylene block copolymer, (B) a rubber component, particularly a thermoplastic rubber component, and (C) talc powder. , (D) formed from a partial metal salt of rosin acid. Therefore, these components will be described below.

(A) Isotactic polypropylene
And / or ethylene / propylene block copolymer isotactic polypropylene is one of the stereoregular polymers, and the physical properties of the molded product are determined by molecular weight, molecular weight distribution and stereoregularity (mmmm fraction by ¹³ C-NMR). Displayed as). Among them, the item related to tacticity is mainly related to the crystallization rate.
Regarding the stereoregularity of polypropylene, a high stereoregularity polypropylene having a mmmm fraction of about 98% has come to be produced due to recent advances in catalyst technology. The stereoregularity of polypropylene in the ethylene / propylene block copolymer has been similarly improved. The isotactic polypropylene used in the present invention is such a highly stereoregular polypropylene.

On the other hand, the ethylene / propylene block copolymer used in the present invention comprises the above-mentioned isotactic polypropylene and a binary copolymer rubber of ethylene / propylene or a ternary copolymer of ethylene / propylene / α-olefin. It is a mixture of copolymerized rubbers, and is a thermoplastic resin that imparts impact resistance by minimizing the reduction in rigidity of polypropylene. Usually rubber component (rubber)
Is contained in an amount of about 10% by weight.

By the way, when the stereoregularity of the isotactic polypropylene is increased, the disorder of the molecular chain configuration, which is a hindrance factor during crystallization, is reduced, and as a result, the crystallization start temperature is increased, and The rigidity is also improved because the degree of conversion is improved. Therefore, it has not been easy to find a crystal nucleating agent having a nucleating agent effect higher than that of talc in a system containing highly stereoregular polypropylene, which is easier to crystallize, and talc, which is a nucleating agent for polypropylene.

The (D) rosin acid partial metal salt, which is an essential component of the polypropylene resin composition of the present invention, exhibits a high nucleating agent effect even in a mixed system of isotactic polypropylene and talc having high stereoregularity. Is what you do.

Therefore, the polypropylene resin composition of the present invention can be used in the range of (A) isotactic polypropylene and (B) within the range of balancing rigidity and impact resistance.
The rubber component may have a composition of (C) talc and (D) a partial metal salt of rosin acid, or (A) a component obtained by blending isotactic polypropylene and an ethylene / propylene block copolymer at an arbitrary ratio; and (B) Rubber component and (C)
The composition may be talc and (D) a partial metal salt of rosin acid. When the amount of rubber contained in the ethylene / propylene block copolymer is sufficient depending on the desired level of impact resistance, the rubber component (B) may be omitted from the above component composition. Furthermore, depending on the desired level of rigidity, isotactic polypropylene may be further omitted from the component composition to obtain (A) an ethylene / propylene block copolymer and (C) talc and (D) a partial metal salt of rosin acid. May be used.

(B) Rubber Component In the polypropylene resin composition of the present invention, (A)
When the impact resistance is insufficient due to the blending of the ethylene / propylene block copolymer, it is preferable to further add a rubber component (B). (B) As the rubber component,
Thermoplastic rubber components are preferred, and specifically, ethylene-propylene copolymer rubber, ethylene-α-olefin copolymer rubber, and ethylene-propylene-α-olefin ternary copolymer having a C2 (ethylene) content of 30 to 90% by weight. Use of one or a mixture of polymerized rubber, ethylene-propylene-diene terpolymer rubber, styrene-butadiene diblock or triblock copolymer, styrene-isoprene diblock or triblock copolymer Can be. Here, the α-olefin in the ethylene-α-olefin copolymer rubber is specifically 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-
Octene, 1-decene, 1-dodecene, 4-methyl-1
-Refers to monomers such as pentene. In addition, the ethylene-α-olefin copolymer rubber used in the present invention may be an amorphous rubber or a rubber partially remaining crystalline.

(C) Talc The talc used in the present invention is a fine powder talc having an average particle size of 0.5 to 10 μm and an aspect ratio (ie, a ratio of the diameter / thickness of the flat talc) of 5 or more. preferable.

(D) Mainly a partial metal salt of rosin acid
Component (D) used in the polypropylene resin composition of the present invention is a crystal nucleating agent containing a rosin acid partial metal salt, that is, a rosin acid partial metal salt as a main component.
Here, the rosin acid partial metal salt refers to a reaction product of rosin acid and a monovalent to trivalent metal compound. That is, the part of the rosin acid partial metal salt in the present invention means that rosin acid and 1
A compound having a reaction rate of 100% or less with a trivalent to trivalent metal compound. Therefore, the component (D) used in the present invention has a reaction rate between rosin acid and the metal compound of 10%.
Not only 0% but also a mixture of unreacted rosin acid and a partial metal salt of rosin acid. In the present invention, the rosin acid is preferably a natural rosin, a modified rosin, or one or more of these purified rosin acids. Examples of the metal compound which reacts with the rosin acid to form a metal salt include monovalent alkali metals, for example, Na,
K, divalent alkaline earth metals such as Mg, Ca,
Among the chlorides, carbonates, hydroxides, acetates, sulfates and the like of Ba and the like and trivalent Al and the like, a compound produced by reaction with the rosin acid is exemplified.

In the present invention, further, the rosin acid partial metal salt is represented by the following formula (1a), (1b), (2a):
(2b), (3a) and (3b)

[0020]

Embedded image (However, in the formulas (1a) to (3b), R ₁ , R ₂ and R ₃ each represent a hydrogen atom, an alkyl group, a cycloalkyl group or an aryl group, and may be the same or different. , M ₁ , M ₂ and M ₃ each represent a monovalent, divalent or trivalent metal as described above), and are at least one partial metal salt represented by one formula selected from the group consisting of Desirably.

The alkyl group includes a methyl group, an ethyl group, an n-propyl group, an iso-propyl group and an iso-
Examples include a butyl group, a tert-butyl group, a pentyl group and an octyl group. As the cycloalkyl group,
Examples include a cyclopentyl group, a cyclohexyl group and a cyclobutyl group. Examples of the aryl group include a phenyl group, a tolyl group and a naphthyl group.

In the present invention, among the compounds represented by the above formulas (1a) to (3b), formula (2a) or (2)
The rosin skeleton represented by b) is a rosin acid partial metal salt bonded to divalent Mg, and R ₁ and R ₂ are both a methyl group and R ₃ is an iso-propyl group. Particularly preferred.

The polypropylene resin composition of the present invention comprises:
(A) Isotactic polypropylene and / or ethylene-propylene block copolymer of 30 to 94
% By weight, preferably 40 to 94% by weight, and (B) 5 to 40% by weight, preferably 5 to 30% by weight of the rubber component,
(C) 1 to 30% by weight of talc powder (provided that (A)
Component, component (B) and component (C) total 100% by weight
And (D) 0.001 to 5 parts by weight, preferably 0.1 to 5 parts by weight of the rosin acid partial metal salt with respect to the resin component (A).
1 to 5 parts by weight. (B) When the addition amount of the rubber component is 5% by weight or less, there is no improvement in impact resistance in the obtained polypropylene resin composition,
% Or more is not preferable because the rigidity of the obtained polypropylene resin composition is significantly reduced. In addition, the amount of the talc powder (C) in the polypropylene resin composition of the present invention is usually 1 to 3 as described above.
Although it is in the range of 30% by weight, the range of 5 to 30% by weight is more preferable, and the range of 10 to 20% by weight is even more preferable. When the content is 1% by weight or less, the rigidity of the obtained polypropylene-based resin composition is not improved. When the content is 30% by weight or more, the obtained polypropylene-based resin composition becomes brittle and the impact strength is reduced.

Furthermore, when the amount of the (D) rosin acid partial metal salt in the polypropylene resin composition of the present invention is less than 0.001 part by weight with respect to the resin component (A), the crystallization rate of polypropylene is reduced. It cannot be improved beyond the nucleating agent effect of talc, and a polypropylene-based resin composition with further improved rigidity while maintaining impact resistance cannot be obtained. On the other hand, even when the addition amount of the (D) rosin acid partial metal salt is more than 5 parts by weight based on the resin component (A), the effect of the (D) rosin acid partial metal salt as a crystal nucleating agent is further increased. Improvement cannot be expected.

As a method for preparing the polypropylene resin composition having such a composition, a known method can be used. For example, the components (A), (B), (C) and (D) are biaxially mixed. A method of melt-kneading using a kneader or the like can be used. There is no particular limitation on the order of blending these components. These components may be blended at the same time, or the components (A), (B) and (C) may be blended in advance and mixed with the mixture. After that, the component (D) may be added from the middle of the cylinder of the twin-screw kneader.
Further, the polypropylene-based resin composition according to the present invention includes an antioxidant, a heat stabilizer, an ultraviolet absorber, a lubricant, an antistatic agent, a flame retardant, a pigment, a dye, talc as long as the object of the present invention is not impaired. Other inorganic fillers and organic fillers may be contained.

[0026]

The present invention will be specifically described below with reference to examples and comparative examples. However, the present invention is not limited to these examples. The following method was used to evaluate the polypropylene-based resin composition according to the present invention.

(1) Crystallization rate The melt-kneaded polypropylene-based resin composition was heated to 230 ° C. by a differential scanning calorimeter (DSC) at which the resin composition was brought into a molten state, and held for 10 minutes. 10 ° C /
The crystallization rate was measured by measuring the peak temperature of heat generation due to crystallization and the temperature at which heat generation ends when cooling was performed at a cooling rate of 1 minute. The higher the peak temperature due to crystallization and the higher the temperature at which heat generation ends, the faster the crystallization speed.

(2) Flexural Modulus In accordance with ASTM D790, a flexural modulus was measured using an injection molded product of a polypropylene resin composition. The higher the flexural modulus, the higher the rigidity.

(3) -30 ° C. Izod Impact Strength Measured at −30 ° C. according to ASTM D256 by notching an injection molded article of a polypropylene resin composition.

Examples 1 and 2 Ethylene / propylene block copolymers (each having a melt flow rate (MFR) measured at 230 ° C. under a load of 2.16 kg of 45 g / 10 min.) At the mixing ratios shown in Table 1. Talc (average particle size: 2.3 microns), potassium salt content of 30% by weight as a nucleating agent represented by the above formula (1a) (wherein M ₁ is metal K)
Or a rosin acid partial metal salt of the formula (2a)
M ₂ is Irganox1010 (Ciba-Geigy as the magnesium salt content 30% by weight of rosin acid partial metal salts and antioxidants represented by a metal Mg) in the formula, the ethylene-propylene block copolymer 0. 1 part by weight) at 230 ° C using a twin-screw kneader.
To prepare a sample.

Then, DSC measurement was performed using the obtained samples shown in Table 1. FIG. 1 shows the measurement results. In Examples 1 and 2, DS obtained from FIG.
Table 2 shows the C peak temperature and the DSC crystallization end temperature.

Comparative Example 1 The amount of the ethylene / propylene block copolymer (the MFR measured at 230 ° C. under a load of 2.16 kg of 45 g / 10 min) was changed to 80 parts by weight to 100 parts by weight. The amount of talc (average particle size: 2.3 microns) was changed to 20 parts by weight to 0 weight, that is, the talc was not used, and the formula (1a) ( However, in the above formula, the amount of the potassium salt of the rosin acid having a potassium salt content of 30% by weight represented by the formula ( ₁ ) is changed to 0.32 part by weight, that is, 0 parts by weight, A sample was prepared by melt-kneading in exactly the same manner as in Example 1 except that no agent was used. Therefore, using the obtained samples shown in Table 1, DSC
A measurement was made. FIG. 1 shows the measurement results. Table 2 shows the DSC peak temperature and the DSC crystallization end temperature determined from FIG.

Comparative Example 2 The amount of a partial metal salt of rosin acid having a potassium salt content of 30% by weight represented by the above formula (1a) (wherein M ₁ is metal K) as a nucleating agent was determined. A sample was prepared by melt-kneading in exactly the same manner as in Example 1 except that 0 parts by weight was used instead of 0.32 parts by weight, that is, the crystal nucleating agent was not used. Then, DSC measurement was performed using the obtained samples shown in Table 1. FIG. 1 shows the measurement results. Table 2 shows the DSC peak temperature and the DSC crystallization end temperature determined from FIG.

[0034]

[Table 1]

[0035]

[Table 2]

As is clear from the results in Table 2 above, the talc-mixed ethylene-propylene block copolymer containing the nucleating agent according to the present invention (that is, the polypropylene-based resin composition according to the present invention) contains only talc. The crystallization peak temperature of 1.7 to 4.3 ° C. moves to a higher temperature side as compared with the case of the ethylene / propylene block copolymer in which is mixed (Comparative Example 2). The crystallization end temperature is also higher by 4.3 to 5.6 ° C. than in the case of the talc-mixed ethylene / propylene block copolymer (Comparative Example 2), and the crystallization ends quickly.

Examples 3 to 7 In Examples 3 to 7, isotactic polypropylene, ethylene / propylene block copolymer, rubber, talc, and A magnesium salt content of 30% by weight of a rosin acid partial metal salt represented by the formula (2a) (wherein M ₂ is metallic Mg) is melt-kneaded in the same manner as in Example 1, A sample was prepared. Next, each sample was injection molded to produce a molded piece having an ASTM standard size. Therefore, in Examples 3 to 7, the bending elastic modulus and the -30 ° C. Izod impact strength were measured using the obtained molded pieces. Table 3 shows the results.

Comparative Example 3 The above formula (2a) (where M ₂ is a metal Mg
30% by weight of magnesium salt represented by
In the same manner as in Example 3 except that the amount of the rosin acid partial metal salt was changed to 0.112 parts by weight to 0 parts by weight, the same composition as in Example 3 containing no nucleating agent was used. Injection molded sample pieces were prepared. Therefore, various physical properties (ie, flexural modulus and -30 ° C. Izod impact strength) of the sample piece were measured. Table 3 shows the results.

Comparative Example 4 The above formula (2a) (where M ₂ is a metal Mg
30% by weight of magnesium salt represented by
In the same manner as in Example 7, except that the amount of the rosin acid partial metal salt was changed to 0.240 parts by weight to 0 parts by weight, the same composition as in Example 7 containing no nucleating agent was used. Injection molded sample pieces were prepared. Therefore, various physical properties (ie, flexural modulus and -30 ° C. Izod impact strength) of the sample piece were measured. Table 3 shows the results.

[0040]

[Table 3]

From the results in Table 3 above, in the case of the polypropylene resin compositions of Examples 3 to 7, the case of the talc-mixed ethylene / propylene block copolymer containing no nucleating agent (Comparative Examples 3 and 4) It is apparent that the bending elastic modulus is improved while maintaining the impact resistance, as compared with the case of FIG.

[0042]

In the polypropylene resin composition according to the present invention, the effect of the rosin acid partial metal salt in the components as a nucleating agent exceeds that of talc as a nucleating agent. Since it is higher than in the case of talc alone and the crystallization speed is also high, the rigidity of the molded article obtained from the resin composition is high, and it is possible to provide a material excellent in the balance of physical properties with little decrease in impact resistance. it can.
Therefore, as described above, the polypropylene resin composition according to the present invention is a material having excellent rigidity while maintaining impact resistance, and is more useful than conventionally known polypropylene resin compositions.

[Brief description of the drawings]

FIG. 1 is a diagram showing the results of DSC measurements of the crystallization behavior of Examples 1 and 2 and Comparative Examples 1 and 2.

[Description of Symbols] EPBC 100% by weight of ethylene / propylene block copolymer Polypropylene 100 resin-based resin composition EPBC / Talc Polypropylene-based resin comprising 80 parts by weight of ethylene / propylene block copolymer and 20 20 parts by weight of TA 80 Composition EPBC / Talc / Ia Ethylene / propylene block copolymer 80 parts by weight 80 20 0.32 parts, talc 20 parts by weight, and rosin acid partial metal salt having a potassium salt content of 30% by weight represented by the above formula (1a) 0.32 Parts by weight of a polypropylene resin composition EPBC / Talc / IIa 80% by weight of 80.20 parts by weight of an ethylene / propylene block copolymer, 20 parts by weight of talc and 30% by weight of a magnesium salt content represented by the above formula (2a) A propylene-based tree comprising 0.32 parts by weight of rosin acid partial metal salt Fat composition Heat flow (W / g) Heat flow (Watt / g)

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification code FI C08L 93/04 C08L 93/04

Claims (3)

[Claims] (A) 30 to 94 parts by weight of an isotactic polypropylene and / or ethylene / propylene block copolymer component, (B) 5 to 40 parts by weight of a rubber component, and (C) 1 to 30 parts by weight of talc. And (D) a nucleating agent containing a metal salt of rosin acid as a main component in an amount of 0.001 to 5 parts by weight based on the resin component (A) (however,
The component (A), the component (B) and the component (C) have a total of 1
00 parts by weight). 2. The polypropylene resin according to claim 1, wherein the partial metal salt of (D) rosin acid is at least one partial metal salt selected from the group consisting of natural rosin, modified rosin, and purified products thereof. Composition. 3. The partial metal salt of rosin acid (D) is represented by the following formula (1a), (1b), (2a), (2b) or (3a)
And (3b) (However, in the formulas (1a) to (3b), R ₁ , R ₂ and R ₃ each represent a hydrogen atom, an alkyl group, a cycloalkyl group or an aryl group, and may be the same or different. , M ₁ , M ₂ and M ₃ are at least one kind of partial metal salt represented by one formula selected from the group consisting of monovalent, divalent and trivalent metals, respectively. Or the polypropylene-based resin composition according to 2.