JPH06172593A - Good-flow high-impact polyolefin composition - Google Patents

Abstract

PURPOSE:To obtain the title composition markedly excellent in flow during processing and impact resistance, especially impact resistance at low temperatures, by mixing a good-flow polyolefin resin with a hydrogenated block copolymer of a specified MFR. CONSTITUTION:60-97 pts.wt. polyolefin resin (A) having an MFR value of 10-60g/10min at 230 deg.C under a load-of, 2.16kg is mixed with 40-3 pts.wt. hydrogenated block copolymer (B) composed of at least one polymer block A based on a vinylaromatic compound and at least one polymer block B based on an olefin compound and hydrogenated to such a degree that the degree of unsaturation of the conjugated diene compound part is not above 20%, having a content of the vinylaromatic compound of 10 to below 30wt.% and an MFR value of 15-60g/10min at 230 deg.C under a load of 2.16 kg, the ratio of the MFR of A to that of B being 0.4-2.5, and 0-40 pts.wt., per 100 pts.wt. in total of components A and B, inorganic filler to obtain the title composition having excellent flow during processing and impact resistance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyolefin composition containing a specific hydrogenated block copolymer having excellent flow processability and impact strength, particularly impact resistance at low temperature, and particularly to high cycle molding. It concerns a suitable material.

[0002]

2. Description of the Related Art Polyolefin resins are generally used for various purposes such as mechanical parts, automobile parts, household products, and various containers because they are excellent in chemical resistance and mechanical properties.
However, the impact resistance strength, especially the impact strength at low temperature, is insufficient, and the purpose of use may be limited.

Therefore, many proposals have been made to add a rubber component to polyolefin for the purpose of improving this problem. For example, Japanese Patent Publication No. 42-19935, Japanese Patent Publication No. 46-8585, Japanese Patent Publication No. 46-16429, and Japanese Patent Publication No. 47-26369 disclose a polyolefin resin, a styrene-butadiene block copolymer,
It has been shown that the addition of thermoplastic elastomers improves impact resistance and stress cracking resistance.

However, since the conventional block copolymers are used in these methods, the impact resistance is not sufficiently improved, and further improvement has been demanded. Further, as a harmful effect of adding the rubber component, there is a tendency that flow processability is deteriorated. Recently, as the molding cycle has been increased and the size of the product has been increased, the birth of a polyolefin composition having excellent flow processability and impact resistance has been demanded. However, flow processability and impact resistance are contradictory properties, and there is no composition having both properties.

For the purpose of improving these points, JP-A 2-15 using a hydrogenated diene random copolymer as a rubber component.
No. 8643 and Japanese Patent Application Laid-Open No. 3-76744 using a block copolymer having a specific molecular weight are disclosed. However, the composition improved in this way is not sufficiently satisfactory in impact resistance at low temperature actually required, and also has low flow processability.

[0006]

The object of the present invention is to provide an excellent impact resistance, in particular, a practical impact resistance at low temperature, and an excellent flow processing method suitable for injection molding and extrusion molding. It is to provide a polyolefin composition.

[0007]

DISCLOSURE OF THE INVENTION The present inventors have investigated the correlation between the physical properties of an elastomer and a polyolefin composition.
As a result of intensive studies, it was found that a composition excellent in impact resistance and flow processability can be obtained by mixing a hydrogenated block copolymer having a specific MFR with a polyolefin resin having good fluidity, The present invention has been completed.

That is, the present invention is: (a) 230 ° C. · 2.1
60 to 97 parts by weight of a polyolefin resin having an MFR value of 10 to 60 g / 10 minutes under a load of 6 kg, (b) at least one vinyl aromatic compound-based polymer block A and the unsaturation of a conjugated diene compound part And a polymer block B mainly composed of at least one olefin compound hydrogenated to a degree not exceeding 20%, and having a vinyl aromatic compound content of 10% by weight to 30% by weight.
Less than 230 ° C, 2.16kg MFR value under load of 15
Hydrogenated block copolymer 40 of -60 g / 10 min
˜3 parts by weight, 10 parts of (c) inorganic filler {(a) + (b)
0)} 0 to 40 parts by weight, and M of (a) and (b)
The polyolefin composition has an FR ratio of 0.4 to 2.5.

The present invention will be described in detail below. The (a) polyolefin-based resin used in the present invention may be any resin as long as it is a resin obtained by polymerizing an α-olefin such as ethylene, propylene, 1-butene, isobutylene or 4-methyl-1-pentene. However, among them, polyethylene, polypropylene, polybutene, polymethylpentene, ethylene-propylene block copolymer, or a mixture thereof may be mentioned. Especially preferred is polypropylene. And, the MFR value under the load of 230 ° C. and 2.16 kg needs to be 10 to 60 g / 10 minutes, and more preferably 12 to 40 g / 10 minutes.

The hydrogenated block copolymer (b) used in the present invention is hydrogenated to the extent that the degree of unsaturation of the conjugated diene compound portion does not exceed 20% with the block A mainly composed of vinyl aromatic compounds. And a polymer B mainly composed of the obtained olefin compound. The polymer block A mainly composed of a vinyl aromatic compound has a weight ratio of the vinyl aromatic compound and the conjugated diene compound of 100/0 to 51/49, preferably from 100/0 to 70/30. When a vinyl aromatic compound and a conjugated diene compound are copolymerized, the distribution of the conjugated diene compound in this block is random, tapered (one in which the monomer component increases or decreases along the molecular chain), It may be either partially block-shaped or any combination thereof.

In the polymer block B mainly composed of the conjugated diene compound, the weight ratio of the vinyl aromatic compound to the conjugated diene compound is 0/100 to 49/51, preferably 0.
When the conjugated diene compound and the vinyl aromatic compound are copolymerized, the distribution of the vinyl aromatic compound in this block is random or tapered (along the molecular chain). The monomer component is increased or decreased), a partial block shape, or any combination thereof.
The vinyl aromatic compound provided here is styrene,
One or more selected from alkyl styrenes such as α-methyl styrene, p-methyl styrene and p-tertiary butyl styrene, paramethoxy styrene, vinyl naphthalene and the like, among which styrene and p-methyl styrene are particularly preferable. preferable. Further, as the conjugated diene compound, butadiene, isoprene, piperylene, methylpentadiene, phenylbutadiene, 3,4-dimethyl-1,3-
One or more selected from hexadiene, 4,5-diethyl-1,3-octadiene and the like, and among them, butadiene and / or isoprene are particularly preferable.

The content of the vinyl aromatic compound must be 10% by weight or more and less than 30% by weight, and the range of 15 to 25% by weight is more preferable. When the content of the vinyl aromatic compound is 30% by weight or more, the effect of improving the impact resistance of the polyolefin composition becomes low. If it is less than 10% by weight, the rigidity tends to be significantly reduced.

In the microstructure of the conjugated diene portion, the vinyl bond content before hydrogenation is preferably 40 to 60%, and more preferably 40 to 50%. Here, the vinyl bond amount means 1,2 in the block copolymer.
Of the conjugated diene compounds incorporated in the bond form of -bond, 3,4-bond and 1,4-bond, the ratio of those incorporated by 1,2-bond and 3,4-bond. When the vinyl bond content is less than 40%, the impact strength at low temperature and the flow processability are not sufficiently improved when the composition is made into a polyolefin composition, and when it exceeds 60%, the impact strength at low temperature decreases again. Tend to. The microstructure of the conjugated diene moiety can be analyzed by nuclear magnetic resonance (NMR).

The hydrogenated block copolymer of the present invention has 2
MFR value under load of 30 ° C and 2.16kg is 15-60g
Must be / 10 minutes. More importantly,
(A) Ratio with MFR value of polyolefin resin {(a)
MFR / (b) MFR} is 0.4 to 2.5, and 0.5 to 2.0 is more preferable. If it is less than 0.4 or exceeds 2.5, the impact resistance required is lowered.

Further, the hydrogenated block copolymer has 2
Blends of MFR components of different types may be blended, and the effect of improving impact resistance is superior to the case of using one type. However, in this case, the average MFR value {(MFR) _av }
Should be between 15 and 60 g / 10 min, and high M
Ratio of FR component (b1) and low MFR component (b2) {(b
The MFR of 1) / (MFR of (b2)) is preferably 1.5 or more and 10 or less {the average MFR value of the hydrogenated block copolymer is calculated by the following formula. log
(MFR) _av = X log {MFR of (b1)} + (1
-X) log {MFR of (b2)}, where X; the proportion of component (b1) in the total hydrogenated block copolymer. Also,
(B1) and (b2) may have the same structure or the same vinyl aromatic compound content, or may have different vinyl aromatic compound contents, as long as they are within the above ranges.

The number average molecular weight of the hydrogenated block copolymer is determined by gel permeation chromatography (GP
It can be measured by a conventional method in C). Number average molecular weight is MFR
Although it is one factor for controlling the value, the number average molecular weight of the hydrogenated block copolymer of the present invention is from 30,000 to
It is 100,000.

The molecular structure of the block copolymer may be linear, branched, radial, or a combination thereof. Then, each of the polymer block mainly composed of vinyl aromatic compound or the block mainly composed of conjugated diene may have the same structure,
The structures of the monomer component content, their distribution in the molecular chain, the molecular weight of the block, and the microstructure may be different.

Examples of the method for producing the block copolymer include, for example, JP-B-36-19286 and JP-B-43-149.
79, Japanese Patent Publication No. 49-36957 and the like. In these, an organic lithium compound or the like is used as an anionic polymerization initiator in a hydrocarbon solvent, an ether compound such as diethyl ether or tetrahydrofuran as a vinylating agent, triethylamine, N,
Tertiary amines such as N, N ', N'-tetramethylethylenediamine, epoxidized soybean oil as a coupling agent, and polyfunctional compounds such as silicon tetrachloride are used as needed, and vinyl aromatic compounds and conjugated diene compounds are used. Is a block copolymer and is obtained as a block copolymer having a linear, branched or radial structure. In the present invention, any polymerization method can be used as long as it is the one described above.

The above block copolymer is prepared by a known method,
For example, a hydrogenated block copolymer can be obtained by hydrogenating according to the method described in JP-B-42-8704. The present invention requires that 80% or more of the conjugated diene moieties be hydrogenated. When the proportion of hydrogenation is low, the compatibility with the polyolefin resin is insufficient and the impact resistance is low, and it is not preferable because it is susceptible to thermal deterioration during mixing and molding. The hydrogenation rate can be analyzed by instrumental analysis using a nuclear magnetic resonance apparatus (NMR).

The hydrogenated block copolymer used in the present invention may be modified by an addition reaction with an unsaturated carboxylic acid or a derivative thereof to contain a functional group.
Modified hydrogenated block copolymers are advantageous when painting is required.

The component (c) of the present invention is an inorganic filler to which talc, calcium carbonate, silica, glass fiber, clay, carbon fiber and the like can be added. Particularly preferred is talc. By adding the component (c), the rigidity is increased, but if it exceeds 40 parts by weight, the impact resistance decreases, which is not preferable.

In the polyolefin composition of the present invention,
The composition is such that the (a) component polyolefin resin is 60
˜97 parts by weight, and the hydrogenated block copolymer of the component (b) is 40 to 3 parts by weight. When the proportion of the hydrogenated block copolymer is less than 3 parts by weight, the effect of improving impact resistance, particularly at low temperature, is not so remarkable, and when it exceeds 40 parts by weight, the rigidity is low. It becomes a molding material and becomes impractical.

Further, other additives such as a heat stabilizer, an antioxidant, an ultraviolet absorber, a coloring agent and a pigment may be added, and a foaming agent is added to the composition of the present invention to obtain a foam. It is also possible to

The composition of the present invention can be prepared by an apparatus which is usually used for mixing polymer substances depending on the composition ratio of each component. Examples of the mixing device include an extruder, a mixing roll, a kneader, and the like.
In the present invention, the melt mixing method using an extruder is preferable.

The polyolefin composition of the present invention can be molded by various conventional molding methods such as injection molding and extrusion molding, and is particularly suitable for high cycle injection molding.

The composition of the present invention is inexpensive, and a product can be obtained by the above-mentioned ordinary molding method. Daily parts, packaging materials, automobile parts such as automobile interior and exterior parts, for example, large bumpers and instruments. It can be used in a wide range of panels and the like, and its industrial utility value is extremely large.

[0027]

EXAMPLES In order to describe the present invention more specifically and in detail, the following examples are shown, but the present invention is not limited to these examples.

The measurement standards and test methods for physical properties shown in Examples and Comparative Examples are as follows. Flowability (MFR) Measured according to JIS K7210. (230 ° C, 2.1
6 kg load) Impact resistance (low temperature) The composition is injection molded to have a thickness of 3 mm, 20 cm x 20 c.
m sheet was molded and fixed to a holder at -30 ° C, and a 13.7 kg weight of a missile type was added to the holder.
It was dropped from a height of 5 m (5.4 m / sec), and it was confirmed whether the sheet was brittle or ductile.

[0029]

[Equation 1]

Flexural Modulus Measured according to JIS K7203.

(I) Preparation of each component (a) component: polyolefin resin (a-1) commercial polypropylene: M7300 {MFR
= 4 (g / 10 minutes) manufactured by Asahi Kasei (Corporation)} (a-2) Commercial polypropylene: M8649 {MFR
= 14 (g / 10 minutes) manufactured by Asahi Kasei (Corporation)} (a-3) Commercially available polypropylene: M7746 {MFR
= 30 (g / 10 minutes) manufactured by Asahi Kasei (Company)} (b) Component: Hydrogenated block copolymer (1) n-butyllithium was used as a polymerization catalyst, and tetrahydrofuran was used as a vinyl content modifier in a cyclohexane solution. The block copolymers shown in Table 1 were synthesized by anionic block copolymerizing styrene and butadiene. The polymer structure was controlled by changing the charged amount of the monomer, the molecular weight of the catalyst and the vinyl content of the vinyl content modifier.

The styrene content is measured by an ultraviolet spectrophotometer (U
V), vinyl content, nuclear magnetic resonance (NMR),
The number average molecular weight was measured using gel permeation chromatography. (2) Next, each block copolymer was hydrogenated at a hydrogen pressure of 5 kg / cm ² and a temperature of 50 ° C. for 2 hours using di-p-trisbis (1-cyclopentadienyl) titanium and n-butyllithium as a hydrogenation catalyst. The addition was made. The hydrogenation rate (hydrogenation rate) of each sample is shown in Table 1. 90% or more of the double bonds in the butadiene block portion were hydrogenated, and the benzene ring in the styrene block portion remained almost unhydrogenated.

The hydrogenation rate is measured by a nuclear magnetic resonance apparatus (NMR).
Was measured using.

[0034]

[Table 1]

(Note 1) S: Styrene polymer block B: Butadiene polymer block (c) Component: Inorganic filler Talc: Microace P-4 (Nippon Talc Co., Ltd.) (II) Preparation of polypropylene composition And measurement of physical properties The respective components (a), (b), and (c) were added at the ratios shown in Tables 2 and 3, and the mixture was heated at 220 ° C. with a 30 mm twin screw extruder.
Melt-kneading was performed at the temperature of to pelletize.

MFR was measured using the obtained pellets.

The pellets thus obtained were injection-molded at 230 ° C. to prepare a sheet and a test piece (tanzaku piece), and the physical properties of impact resistance and flexural modulus at low temperature (−30 ° C.) were measured. The results of Examples 1 to 10 below are shown in Table 2.

Examples 1 to 6 are examples of compositions having a free-flowing polypropylene and a hydrogenated block copolymer having an MFR ratio defined in the present invention.
It has not only excellent flowability and rigidity, but also excellent impact resistance.

Examples 7 to 10 are examples in which two types of hydrogenated block copolymers having different MFRs are used and the average MFR is within the range specified in the present invention.

All of these examples are compositions included in the constitution of the present invention, and have excellent flow processability and impact resistance at low temperature.

[0041]

[Table 2]

The superiority of the characteristics will be further clarified by comparison with the following comparative examples. The results of Comparative Examples 1 to 10 below are shown in Table 3.

Comparative Example 1 This is an evaluation of polypropylene alone, and the impact resistance at low temperature is extremely low.

Comparative Example 2 The same hydrogenated block copolymer as in Examples 1 and 2 of the present invention was used, but the flexural modulus was remarkably lowered due to a large block copolymerization ratio, which was not practical.

Comparative Examples 3 to 5 The MFR ratios of polypropylene and hydrogenated block copolymer were
Although it is a composition outside the scope of the present invention, it has poor impact resistance at low temperatures.

Comparative Example 6 A composition using a hydrogenated block copolymer having a high styrene content, but the impact resistance at low temperature is inferior.

Comparative Examples 7 and 8 MFR is a composition using a hydrogenated block copolymer other than the present invention, but the impact resistance at low temperature is poor.

Comparative Examples 9 and 10 A composition using polypropylene having low fluidity,
Poor balance of flowability and impact resistance.

[0049]

[Table 3]

[0050]

INDUSTRIAL APPLICABILITY The present invention is a composition containing a polyolefin resin having a good fluidity and a hydrogenated block copolymer having a specific MFR, which has a remarkably excellent flow processability and impact resistance.
In particular, it has impact resistance at low temperatures.

The composition of the present invention can be molded by injection molding, extrusion molding and the like, and is particularly suitable for high cycle injection molding. The obtained product can be widely used from daily parts and packaging materials to automobile parts such as automobile interior and exterior products, and has an extremely high industrial utility value.

Claims (1)

[Claims] 1. A main component of (a) 60 to 97 parts by weight of a polyolefin resin having an MFR value of 10 to 60 g / 10 minutes under a load of 230 ° C. and 2.16 kg, and (b) at least one vinyl aromatic compound. And a polymer block B mainly composed of at least one olefin compound hydrogenated to an extent that the degree of unsaturation of the conjugated diene compound portion does not exceed 20%. 40 to 3 parts by weight of a hydrogenated block copolymer having a content of 10% by weight or more and less than 30% by weight and an MFR value of 15 to 60 g / 10 minutes under a load of 230 ° C. and 2.16 kg, (c) an inorganic filler {(A) + (b) as 100} 0
To 40 parts by weight, and the MFR ratio of (a) and (b) is 0.4 to 2.5.