JPH08302096A - Polypropylene resin composition and injection molded product - Google Patents

Abstract

PURPOSE: To obtain a polypropylene resin composition exhibiting a high impact- resistant strength and simultaneously excellent in whitening resistance, and to obtain its injection molded product. CONSTITUTION: A polypropylene resin composition comprises (A) 66-99wt.% of an impact-resistant polypropylene resin and (B) 34-1wt.% of an ethylene/α- olefin copolymer elastomer satisfying the below-described requirements (a)-(d), and a molded product is obtained by injection-molding the composite material. (a) The number of carbon atoms contained in the α-(4-20C) olefin is 4-20. (b) The content of the α-olefin is 65-95wt.%. (c) The density of the elastomer is < 0.88g/cm<3> at 23 deg.C. (d) The melting peak of a crystal is not observed by the use of a differential scanning calorimeter.

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 a polypropylene resin composition having high impact resistance and excellent whitening resistance, and a molded product thereof.

[0002]

2. Description of the Related Art Polypropylene resins (hereinafter referred to as PP) are widely used for various purposes due to their excellent heat resistance and rigidity. In particular, impact PP (also referred to as block PP) obtained by blowing ethylene gas at the polymerization stage is composed of polypropylene, ethylene / propylene copolymer elastomer, polyethylene and ethylene / propylene block copolymer. , Is known to exhibit excellent impact strength. However, the impact PP has a problem in that whitening is severe when the impact is applied or when the impact PP is bent.

On the other hand, in the automobile field, a method of fitting and assembling parts is being adopted for the purpose of simplifying the manufacturing process, and there is a strong demand for a product which is not bleached by the impact at the time of fitting. Further, home appliances, containers, daily necessities, etc. lose their commercial value when they are bleached, and therefore improvements have been strongly desired.

Further, when injection molding the impact PP, pursuit of shortening the molding cycle may cause whitening due to the protruding pin, which causes many problems such as restrictions on the product shape.

As described above, the demand for whitening is extremely great, but the conventional impact PP cannot meet the needs of the market, which is a big problem.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and is a polypropylene resin composition having high impact resistance and excellent whitening resistance, and its injection molding. The purpose is to provide products.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to achieve the above object, and as a result, completed the present invention. That is, the present invention relates to impact polypropylene resin (A) 66 to 99% by weight, and the following (a) to
The present invention relates to a polypropylene resin composition comprising 34 to 1% by weight of an ethylene / α-olefin copolymer elastomer (B) satisfying the requirement (d), and an injection molded product thereof.

(A) The α-olefin has 4 or more carbon atoms 2
0 or less (b) The content of α-olefin is more than 65% by weight and 95
Weight% or less (c) Density at 23 ° C. is less than 0.88 g / cm ³ (d) No crystal melting peak is observed by a differential scanning calorimeter. The details will be described below.

The impact polypropylene resin (A) used in the present invention is Japanese Patent Publication No. 38-14834,
It is produced by a known method as known from JP-B-39-1836, JP-B-39-15535 and the like, and for example (i) a magnesium compound, a titanium compound and a catalyst component containing chlorine as essential components, (Ii) Ia, IIa, IIb, IIIb, IV of the periodic table as the component
In the step (I), in the block copolymerization of propylene and ethylene in the presence of a catalyst comprising at least one selected from the group b metal organometallic compounds and (iii) an electron-donating compound, propylene alone is used. ,
Or the reaction ratio of ethylene and propylene is 5/9 by weight.
5 or less copolymer is carried out, 55 to 95% by weight of the total polymer
Etc., and in the step (II), a copolymer having a reaction ratio of ethylene and propylene of 10/90 to 90/10 by weight is carried out to obtain 45 to 5% by weight of the total polymer. Is mentioned. The composition of impact polypropylene resin (A) is not particularly limited, but the ethylene content is 1
It is preferably in the range of up to 60% by weight because it is easily available.

The melt flow rate of the impact polypropylene resin (A) is not particularly limited,
A load of 0.01 to 100 g / 10 min under a load of 2.16 kg is used.

Ethylene / α-used in the present invention
The α-olefin of the olefin copolymer elastomer (B) has 4 to 20 carbon atoms, and includes, for example, butene-1, pentene-1, hexene-1, 4-methyl-pentene-1, heptene-1, Octene-1, Nonene-
1, decene-1, undecene-1, dodecene-1, tridecene-1, tetradecene-1, pentadecene-1, hexadecene-1, heptadecene-1, octadecene-
1, nonadecene-1, eicosene-1, and the like, and one or more of these are used. Among them, butene-1, heptene-1, and hexene- are easily available.
1, octene-1 are preferred.

Ethylene / α-used in the present invention
The α-olefin content of the olefin copolymer elastomer (B) is more than 65% by weight and 95% by weight or less, preferably 70% by weight or more and 90% by weight or less. When the α-olefin content is 65% by weight or less, the compatibility with the impact polypropylene resin (A) used together with the ethylene / α-olefin copolymer elastomer (B) becomes poor and the whitening property of the composition decreases. Further, when the α-olefin content is more than 95% by weight, the glass transition temperature of the ethylene / α-olefin copolymer elastomer itself rises, and as a result, the cold resistance of the obtained resin composition is lowered.

Ethylene / α-used in the present invention
The density of the olefin copolymer elastomer (B) at 23 ° C. is less than 0.88 g / cm ³ . Density 0.8
If the ethylene / α-olefin copolymer is 8 g / cm ³ or more, the whitening property of the obtained resin composition is lowered.

Ethylene / α-used in the present invention
The olefin copolymer elastomer (B) is characterized in that no crystal melting peak is observed by a differential scanning calorimeter (abbreviated as DSC). When an ethylene / α-olefin copolymer showing a crystal melting peak is used, the whitening property of the obtained resin composition is lowered.

Ethylene / α-used in the present invention
The molecular weight of the olefin copolymer elastomer (B) is not particularly limited, but the number average molecular weight measured by gel permeation chromatography (GPC) is preferably 5,000 to 1,000,000 in terms of polyethylene, and more preferably 10,000-60
It is 0000. If the number average molecular weight is less than 5,000, the surface of the composition may be sticky. On the other hand, if the number average molecular weight exceeds 1,000,000, the fluidity of the resulting composition may be lowered, and molding may be difficult.

Ethylene / α-used in the present invention
The molecular weight distribution (Mw / Mn) of the olefin copolymer elastomer (B) is not particularly limited, but is preferably 3 or less. It is generally known that the larger the molecular weight distribution, the larger the composition distribution. When the composition distribution is wide, ethylene /
The compatibility between the α-olefin copolymer elastomer (B) and the impact polypropylene resin (A) becomes poor,
It becomes difficult to obtain the resin composition of the present invention. 10% of high molecular weight fraction fractionated by GPC as an index of composition distribution
The ratio of the average α-olefin content (mol%) in the low molecular weight fraction of 10% to the average α-olefin content (mol%) in the medium is used, but the ratio of both is 1.2 or less, more preferably 1. When it is 15 or less, an excellent whitening property is obtained.

The resin composition of the present invention comprises 66 to 99% by weight of impact polypropylene resin (A) and ethylene / α-.
Olefin copolymer elastomer (B) 34 to 1% by weight
Consists of When the polypropylene resin (A) is more than 99% by weight, the whitening property of the obtained composition may be lowered, and when the polypropylene resin (A) is less than 66% by weight, the rigidity of the obtained composition is lowered. There is a risk of

The method for producing the ethylene / α-olefin copolymer elastomer (B) described above is not particularly limited,
It can be produced using various catalysts such as a titanium-based catalyst, a vanadium-based catalyst, or a metallocene-based catalyst. Above all, it is preferable to use a metallocene-based catalyst that is easy to obtain an ethylene / α-olefin copolymer elastomer satisfying the above-mentioned molecular weight, molecular weight distribution and composition distribution.

That is, (a) a transition metal compound containing a transition metal of Group 4 of the periodic table, (b) a compound which reacts with this to form an ionic complex, and (c) an organometallic compound, if necessary. The ethylene / α-olefin copolymer elastomer can be produced by copolymerizing ethylene and α-olefin in the presence of the catalyst consisting of

The polymerization can be carried out by any of batch method, semi-continuous method and continuous method, and it can also be carried out in two or more stages by changing the polymerization conditions. Further, the copolymer obtained after the completion of the polymerization is separated and recovered from the polymerization solution by a conventionally known method and dried to obtain a solid copolymer.

In the resin composition of the present invention, it is desirable that the long period, which is the average distance of the center of gravity of the crystals, be larger than that of the impact polypropylene resin (A) alone. Due to this property, the whitening property is further excellent. The long period can be obtained by small-angle X-rays, but can also be estimated by Raman spectroscopy and measurement of crystallinity. Crystallinity is wide angle X
It can be evaluated by line, density, thermal analysis and the like.
Either method may be used, but the impact polypropylene resin to be used for comparison must be molded under the same conditions.

In the resin composition of the present invention, the glass transition temperature of the PP phase, which is evaluated by the temperature dependence of dynamic viscoelasticity, may be 1 ° C. or more lower than that of the impact polypropylene resin (A) alone. Desirably, this property further improves the whitening property. When evaluated by dynamic viscoelasticity, the glass transition temperature can be evaluated as the maximum temperature of the loss tangent (tan δ), but the impact PP is the rubber phase and P
Corresponding to each of the P phase, 2 in the temperature range of -80 ℃ ~ 40 ℃
There are two maxima. Among these, it is known that the maximum on the high temperature side corresponds to the glass transition of the PP phase.

In the composition of the present invention, if necessary, calcium carbonate, mica, talc, silica, barium sulfate, calcium sulfate, kaolin, clay, pyroferrite,
Bentonite, serisanite, zeolite, nepheline sinite, attapulgite, wollastonite, ferrite, calcium silicate, magnesium carbonate, dolomite, antimony trioxide, zinc oxide, titanium oxide, magnesium oxide, iron oxide, molybdenum disulfide, graphite, gypsum , Glass beads, glass powder, glass balloons,
Inorganic fillers such as quartz and quartz glass, and organic and inorganic pigments can be blended. Also, a crystal nucleating agent, a clarifying agent, an anti-blocking agent, a release agent, an antistatic agent, a slip agent, an antifogging agent, a lubricant, a heat resistance stabilizer, an ultraviolet light stabilizer, a weather resistance stabilizer, a foaming agent, an antifungal agent. , Rust inhibitor, ion trap agent,
A flame retardant, a flame retardant aid, and the like may be added if necessary. Further, high-density polyethylene, low-density polyethylene, linear low-density polyethylene, polybutene-1, poly (4-methyl-pentene-1) and ethylene / vinyl acetate are used so long as the performance of the resin composition of the present invention is not deteriorated. You may blend 1 type, or 2 or more types of a polymer.

The resin composition of the present invention can be obtained by blending the impact polypropylene resin (A) and the ethylene / α-olefin copolymer elastomer (B) by a commonly used method. It is preferably produced by melt blending using a Banbury mixer, an extruder or the like.

A molded product obtained by injection, compression, profile extrusion of the polypropylene resin composition of the present invention and any one of film, vacuum, compressed air, transfer, and blow molding methods exhibits high impact strength and whitening. A molded product with excellent characteristics. Particularly in injection molding, the probability of whitening of the molded product due to the ejecting pin is greatly reduced in the ejecting step after the cooling step, and the yield is improved.

[0026]

The present invention will be described below with reference to examples, but these are illustrative and not limiting. Various measurements in Examples and the synthesis of ethylene / α-olefin copolymer elastomers were carried out by the following methods.

(Α of ethylene / α-olefin copolymer
—Measurement of Olefin Content) It was calculated by measuring ¹³ C-NMR spectrum (JNM GX400 manufactured by JEOL Ltd.) in o-dichlorobenzene as a solvent at 100 MHz.

(Measurement of molecular weight and molecular weight distribution) o-
Gel permeation chromatography (manufactured by Millipore Corporation) at 140 ° C. using dichlorobenzene.
It was calculated in terms of polyethylene by using 150C type GPC).

Reference Example 1 Synthesis of ethylene / butene-1 copolymer elastomer 1000 ml of toluene and 500 ml of butene-1 were added to a 5 l autoclave and the temperature was raised to 40 ° C. Furthermore, ethylene was introduced so that the total pressure would be 8 kg / cm ² . Then, in another reaction container, 10 ml of toluene, 5 mmol of methylaluminoxane, (dimethyl (t-butylamide) (tetramethyl-η5-cyclopentadienyl))
After adding 5 μmol of titanium (silane) dichloride and stirring the mixed solution for 20 minutes, the mixture was introduced into an autoclave to start polymerization. This polymerization has a total pressure of 8 kg / cm ^2.
Ethylene was continuously introduced to keep
Minutes.

After the completion of the polymerization, the polymer was washed with a large amount of ethanol and dried under reduced pressure at 60 ° C. for 12 hours. As a result, 44 g of an ethylene / butene-1 copolymer elastomer having a butene-1 content of 72% by weight was obtained. Number average molecular weight 108,000, Mw / Mn = 2.2, density 0.86
It was 4 g / cm ³ .

Example 1 Impact PP (Tosoh Polypro J7091B, ethylene content: 8.0%, MFR: 9.0 g / 10 minutes) 162
g and 18 g of the ethylene / butene-1 copolymer elastomer obtained in Reference Example 1, a hindered phenolic stabilizer (Irganox 1010 (manufactured by Ciba Geigy)) as a heat stabilizer, and a phosphorus stabilizer (Irgafoss). 168 (manufactured by Ciba-Geigy), 2000 ppm each, calcium stearate as a lubricant: 5000 ppm, and 1 g carbon black in Labo Plastmill (internal volume 200 c
c) was melt blended at 60 rpm for 5 minutes at 200 ° C. After that, the obtained composition was finely broken and 2 m by an injection molding machine (Minimat, manufactured by Sumitomo Heavy Industries).
A flat plate having a thickness of m and an Izod test piece having a thickness of 3.2 mm were molded to obtain a molded product.

Reference Example 2 Synthesis of ethylene / butene-1 copolymer elastomer 400 ml of toluene and 1100 ml of butene-1 were added to a 5 l autoclave and the temperature was raised to 40 ° C. Furthermore, ethylene was introduced so that the total pressure would be 8 kg / cm ² . Next, 10 ml of toluene, 3 mmol of methylaluminoxane, and 3 μmol of diphenylmethane (cyclopentadienyl-1-fluorenyl) zirconium dichloride were added to another reaction vessel, and the mixed solution was stirred for 20 minutes and then introduced into an autoclave to start polymerization. did.
This polymerization was carried out at 40 ° C. for 60 minutes by continuously introducing ethylene so that the total pressure was kept at 8 kg / cm ² .

After completion of the polymerization, the polymer was washed with a large amount of ethanol and dried under reduced pressure at 60 ° C. for 12 hours. As a result, 102 g of an ethylene / butene-1 copolymer elastomer having a butene-1 content of 77% by weight was obtained. Number average molecular weight 45,000, Mw / Mn = 2.6, density 0.86
It was ³ g / cm ³ .

Various ethylene / butene-1 copolymer elastomers were obtained by changing the amount of butene-1 and performing the same operation as above. Also, butene-1 was changed to hexene-1 and propylene to obtain various ethylene / α-olefin copolymer elastomers. The copolymers used are summarized in Table 1.

Example 2 Instead of the ethylene / butene-1 copolymer elastomer used in Example 1, the ethylene / butene-1 copolymer obtained in Reference Example 2 was used.
A molded product was obtained in the same manner as in Example 1 except that the butene-1 copolymer elastomer was used.

Example 3 Instead of the ethylene / butene-1 copolymer elastomer used in Example 1, the hexene-1 content was 77% by weight.
A molded product was obtained in the same manner as in Example 1, except that the ethylene / hexene-1 copolymer elastomer was used.

Example 4 A molded product was obtained in the same manner as in Example 1 except that the impact PP was 171 g and the ethylene / butene-1 copolymer elastomer was 9 g.

Example 5 Example 5 was repeated except that the impact PP used in Example 1 was replaced with another impact PP (Tosoh Polypro J7090B, ethylene content: 7.0%, MFR: 9.0 g / 10 min). A molded product was obtained in the same manner as in Example 1.

Example 6 A molded product was prepared in the same manner as in Example 1 except that 154 g of impact PP, 16 g of ethylene / butene-1 copolymer elastomer and 20 g of talc (FSM Talc, LSM # 300) were used. Obtained.

Comparative Example 1 Impact PP (Tosoh Polypro J7) used in Example 1
091B) was injection-molded to obtain a molded product.

Comparative Example 2 Impact PP used in Example 5 (Tosoh Polypro J7
090B) was injection molded to obtain a molded product.

Comparative Example 3 The same procedure as in Example 1 was repeated except that the ethylene / butene-1 copolymer elastomer used in Example 1 was replaced by an ethylene / butene-1 copolymer elastomer having a butene-1 content of 53% by weight. A molded product was obtained by the above method.

Comparative Example 4 Instead of the ethylene / butene-1 copolymer elastomer used in Example 1, the hexene-1 content was 61% by weight.
A molded product was obtained in the same manner as in Example 1, except that the ethylene / hexene-1 copolymer elastomer was used.

COMPARATIVE EXAMPLE 5 An ethylene / propylene copolymer elastomer having a propylene content of 75% by weight was used in place of the ethylene / butene-1 copolymer elastomer used in Example 1, and molding was carried out in the same manner as in Example 1. I got the goods.

Reference Example 3 Synthesis of ethylene / butene-1 copolymer elastomer 500 ml of toluene and 1000 ml of butene-1 were added to a 5 l autoclave and the temperature was raised to 40 ° C. Further, ethylene was introduced so that the total pressure would be 4 kg / cm ² . Next, 10 ml of toluene, 3 mmol of methylaluminoxane, and dimethylsilylbis (2-
Methylindenyl) zirconium dichloride 3μmo
1 was added, the mixed solution was stirred for 20 minutes, and then introduced into an autoclave to initiate polymerization. This polymerization was carried out at 40 ° C. for 30 minutes by continuously introducing ethylene so as to keep the total pressure at 4 kg / cm ² .

After completion of the polymerization, the polymer was washed with a large amount of ethanol and dried under reduced pressure at 60 ° C. for 12 hours. As a result, 54 g of an ethylene / butene-1 copolymer elastomer having a butene-1 content of 96% by weight was obtained. The number average molecular weight is 76000, Mw / Mn = 2.4, and the density at 23 ° C. is 0.882 g / cm ^3, which is measured by DSC.
The crystal melting point measured as the main peak was 45 ° C.

Comparative Example 6 The same procedure as in Example 1 was carried out by using the ethylene / butene-1 copolymer elastomer obtained in Reference Example 3 instead of the ethylene / hexene-1 copolymer elastomer used in Example 1. A molded product was obtained.

Comparative Example 7 Instead of the impact PP used in Example 1, PP
Homopolymer (Tosoh Polypro J5100A, MFR: 1
A molded product was obtained in the same manner as in Example 1 except that 0 g / 10 min) was used.

Comparative Example 8 In Example 1, 90 g of impact PP and ethylene /
A molded product was obtained in the same manner as in Example 1 except that 90 g of butene-1 copolymer elastomer was used, but the surface tackiness was poor.

The molded articles obtained above were evaluated by the following methods. The results are shown in Table 1.

[0051]

[Table 1]

(Izod Impact Test) An Izod impact test was conducted at a temperature of 23 ° C. according to JIS K7110. The weighing capacity was 1.96 J and the impact speed was 3.35 m / sec.

(Impact whitening test) Load from height 80 cm 1
A whitening area was evaluated by visually observing a test piece 1 hour after dropping an impacting body of 000 g and an impact weight diameter of 0.5π on a flat plate. 5 mm 2 mm flat plate with a pedestal inner diameter of 43 mm
It was used after being cut into 0 mm × 50 mm.

[0054]

As described above, the resin composition of the present invention and the molding material thereof exhibit high impact resistance and excellent whitening resistance, and in particular, whitening due to the ejection pin during injection molding can be suppressed. .

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area C08L 23:18) B29K 23:00

Claims (2)

[Claims] 1. Impact polypropylene resin (A) 6
6 to 99% by weight of ethylene / α-olefin copolymer elastomer (B) satisfying the following requirements (a) to (d):
A polypropylene resin composition comprising 34 to 1% by weight. (A) Carbon number of α-olefin is 4 or more and 20 or less (b) Content of α-olefin is more than 65% by weight 95
Weight% or less (c) Density at 23 ° C. is less than 0.88 g / cm ³ (d) No crystal melting peak is observed by differential scanning calorimeter 2. A molded article produced by injection-molding the composite material according to claim 1.