JPS59204646A - Polypropylene resin composition - Google Patents

Abstract

PURPOSE:To obtain the titled composition having improved extrusion moldability and especially injection moldability, and excellent mechanical property and impact resistance, by compounding a polypropylene resin with a specific ethylene-propylene copolymer rubber. CONSTITUTION:The objective composition can be prepared by compounding (A) 5-50wt% of an ethylene-propylene copolymer rubber wherein the ratios (wt%) of (ethylene):(propylene):(conjugated diene) are (15-70):(30-85):(0-15), the ratio of the weight average molecular weight Mw to the number average molecular weight Mn (Mw/Mn) is 4-18, the heat of fusion between 100 deg.C and 140 deg.C is <=1cal/g measured by differential thermal analysis, the difference between the propylene content in the low-molecular weight part accounting for 15wt% of the whole polymer (a%) and the propylene content in the high molecular weight part accounting for 15wt% of the whole polymer (b%), i.e. a-b, is >10, and the content of the inversely bonded propylene is <=5mol%, with (B) 50-95wt% of a propylene homopolymer or a copolymer of propylene containing <=20wt% of ethylene.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polypropylene resin composition that has excellent mechanical properties and impact resistance, and has improved extrusion processability (flowability) and is suitable for injection molding.

Crystalline polypropylene has many excellent properties such as high rigidity, high heat distortion temperature, and good surface hardness, and is widely used today as a general-purpose resin for many applications, but it has low impact resistance and is brittle. There is a drawback. A common method for overcoming these drawbacks is to mechanically mix synthetic rubbers such as ethylene-propylene copolymer rubber and polyimbutylene rubber.

The above-mentioned ethylene-propylene copolymer rubber has conventionally been produced using vanadium and an organoaluminum catalyst.

This rubber has extremely high random copolymerizability of ethylene and propylene, and the propylene bonds are reversed (1n
version) A large amount of bonds exist, and the compatibility with polypropylene resin is poor.

In addition, many methods for producing ethylene-propylene copolymers using titanium catalysts have been proposed (Japanese Patent Laid-Open No. 50-95
382, 52-98045, 53-88049
.

53-104687, etc.). However, the copolymers obtained by these methods are not rubber-like, but are mixtures containing a large amount of homopolymers of polyethylene and polypropylene, and are resin-like copolymers. Even if these resinous copolymers are mixed with polypropylene resin, the effect of improving impact resistance is small.

The present inventors have developed an ethylene-propylene copolymer rubber that can be mixed with polypropylene resin to improve its mechanical properties and impact resistance, as well as its extrusion processability, particularly injection moldability. We have been conducting development and research. As a result, using a Ti-based catalyst, (i) the ratio of ethylene, propylene and non-conjugated diene was 15-70/30-8510-15 (wt%), (i:) the weight average molecular weight My and the number average The molecular weight ratio My/Mn is 4 to 18, (ii) the heat of fusion in the range of 100 to 140 °C as determined by differential thermal analysis is 1 cyd,/g or less, and Ov)
The propylene content of the low molecular weight portion (A weight %) which accounts for 15 weight % of the total copolymer and the propylene content of the high molecular weight portion (A weight %) which accounts for 15 weight % of the total copolymer.
(V) An ethylene-propylene copolymer rubber having a structure that satisfies the relationship A-B>10 and has a propylene inversion bond (1nversion) content of 5 moles or less in C''-NMR analysis. The composition mixed with the polypropylene resin has the following characteristics: 1) The time required to reach the maximum torque when the polypropylene resin and rubber are mixed together with a burr is short, and the composition has good kneading properties.

2) It was discovered that the resin composition has very good flowability and good extrusion processability compared to other resin compositions that have almost the same physical properties such as Izot impact strength, flexural modulus, and hardness, and the present invention has been reached.

That is, the gist of the present invention is that (i) the ratio of ethylene, propylene and non-conjugated diene is 15 to 70/30 to 8510 to 15 (wt%), (11) the weight average molecular weight Mw and the number average molecular weight Mn ratio M
w/Mn is 4 to 18, (ii) the heat of fusion in the range of 100 to 140°C by differential thermal analysis is 1 cd 79 or less, and Ov) the low molecular weight portion accounts for 15% by weight of the total copolymer. propylene content (A weight qb) and 15% by weight in the total copolymer.
(V) satisfies the relationship A-B)10 between the propylene content (8% by weight) of the high molecular weight portion that occupies Ethylene-propylene copolymer rubber having a structure 5 to 50
(2) 50 to 95% by weight of a polypropylene homopolymer or a copolymer containing 20% by weight or less of ethylene.

The resin composition of the present invention can be obtained by mixing polypropylene with an ethylene-propylene copolymer rubber having the following characteristics (1) to (5).

That is, (1) It consists of a composition in which the ratio of ethylene/propylene/nonconjugated diene is 15 to 70/30 to 8510 to 15% by weight. As the non-conjugated diene, 1,4-hexadiene,
1,5-hebutadiene, 1,6-octadiene, 1,4
- non-conjugated aliphatic hydrocarbon diene compounds such as hebutadiene, 1,5-octadiene, 1,4-octadiene,
Non-conjugated cyclic aliphatic hydrocarbon diene compounds such as cyclooctadiene, cyclododecatriene, dicyclopentadiene, ethylidenenorbornene, butylidenenorbornene, vinylnorpolene, propenylnorbornene, ingropenylnorbornene or mixtures thereof may be mentioned. However, lcl, 4-hexadiene, dicyclopentadiene, and ethylidene norbornene are preferred. Also, the ratio of ethylene/propylene/non-conjugated diene is 2
More preferably, the composition ranges from 5-70/30 to 7510-8% by weight. Outside this range, rubber-like (2
) The ratio of weight average molecular weight My to number average molecular weight Mn is Mw/
Mn = 4-18. If Mw/Mn is less than 4, the inversion bond (1nversion) of propylene will increase, the regularity of the propylene part will be disturbed, and the bond of ethylene and propylene will be random, resulting in a copolymer, and even if blended with polypropylene, crosstalk will occur. The properties and flow properties are not improved. Furthermore, when My/Mn exceeds 18, the molecular weight distribution becomes too broad, and many low molecular weight copolymers are produced.
When blended with polypropylene, a decrease in tensile strength and a plume phenomenon occur, which is undesirable.

(3) The heat of fusion in the range of 100 to 140°C by differential thermal analysis is 1 eat/11, preferably 0.7 c
at/9 or less. 1 cat/j! If you exceed
The number of ethylene bonds in Chorengin, which corresponds to polyethylene, increases, making it resin-like rather than a rubber-like copolymer, and the effect of adding polypropylene and modifying it becomes smaller. When ethylene and propylene are copolymerized using a common polyethylene or polypropylene catalyst, the heat of fusion exceeds 1 cd/g.

(4) The compositional distribution of propylene in the copolymer consists of a low molecular weight propylene content (A weight %) that accounts for 15 weight % of the total copolymer and a high propylene content (A weight %) that accounts for 15 weight % of the total copolymer. The propylene content (8% by weight) of the molecular weight portion has a relationship of A-B) of 10, preferably of A-B) of 15.

This indicates that the composition contains many propylene chains on the low molecular weight side and that many ethylenes are bonded on the high molecular weight side. In other words, when blended with polypropylene, a composition with many propylene chains present on the low molecular side improves flowability, and a composition with relatively long ethylene chain lengths on the high molecular side (sum of lengths that form polyethylene crystals). Improve impact strength and bending strength with materials. Composition distribution is A-B<1
When it is 0, the effect of maintaining impact strength and bending strength of 7 and improving flowability is small.

This propylene composition distribution can be determined by GPC-FT-IR or precipitation method. GPC-FT-
FT-IR (FT-IR, DigiLab) gel permeation chromatogram of 150C gel
S-1sc/n), which allows the propylene content of the copolymer to be determined.

Further, the precipitation method is carried out as follows.

The copolymer was dissolved in cyclohexane at room temperature, and the insoluble matter was filtered through an 80-mesh wire mesh. Add isopropyl alcohol little by little to the soluble portion, remove the precipitate, and measure the propylene content in the polymer. Add a further small amount of isopropyl alcohol, repeat the same operation several times, and finally use an evaporator to remove dicyclohexane and inpropyl alcohol from the fraction that does not precipitate to determine the propylene content in the polymer. B
The overlapping area and the A overlapping area can be determined from the propylene content of the polymer, which is 15% by weight in the total copolymer that is finally precipitated.

A representative example of the propylene composition distribution determined in this way is shown in the drawing.

(5) Propylene-propylene bonding mode (, l
In , cl 3-NMR analysis, the propylene inversion bond (1nversion) content is 5% or less. Head-to-head bonds or tail-to-tail bonds of propylene can be determined from methylene chains in the polymer by CILNMR. If the amount of reverse coupling exceeds 5 molti, crosstalk and flowability will not be improved.

The ethylene-propylene copolymer rubber having the structures (1) to (5) above can be produced using a Ti compound catalyst and an organoaluminum compound catalyst.

As the Ti compound catalyst, for example, a homogeneous solution catalyst containing a titanium compound (JP-A-56-53112゜56-531
13.56-112917.56-59815.56-
59813.

56-59814, 56-151710, 56-1
55210 Patent application No. 56-158864, 57-6
5491), solid catalyst containing titanium compound (% Gansho 5
6-209713, 57-65489, 57-65
490.57-65492. 57-'92131.
57-99955. The Ti compound catalysts described in the above-mentioned publications and application specifications such as No. 57-118670) can be used, but the catalyst is not limited to these examples. Particularly preferred is JP-A-56-5981.
5, 56-151710, patent application No. 56-20971
3, 57-65492, 57-92131.

Examples of organoaluminum compounds include triethylaluminum, tri-n-propylaluminium, and tri-isopropylaluminum.

tri-n-butylaluminum, triisobutylaluminum, )! J-n-hexylaluminum, tri-n
-Octyl aluminum.

tri-n-decylaluminum, tri-n-dodecylaluminum, diethyl monochloraluminum, dibutyl monochloraluminum, di-n-hexyl monochloraluminum, di-n-octylmonochloraluminum, ethylaluminum sesquichloride, n-butylaluminum sesquichloride, ethylaluminum Dichloride, n-butylaluminum dichloride, isobutylaluminum dichloride, n-hexylaluminum dichloride, n-octylaluminum dichloride, and the like. Reactants of these organoaluminiums and alcohols, amines, etc. can also be used. For example, methanol, ethanol, n-propertool, iso\propertool, n-butanol, imbutanol, t
-butanol, n-hexanol.

n-octatool, 2-ethyl-hexanol.

n-decal, triethylamine, tri-n-propylamine, tri-n-butylamine.

tri-n-butylamine, tri-n-hexylamine,
tri-n-octylamine, tri-2-ethylhexylamine, diethylamine, di-n-butylamine, di-
Isobutylamine, di-n-octylamine, di-2-
These are ethylhexylamine, ethylamine, n-propylamine, n-butylamine, isobutylamine, and 2-ethylhexylamine. The ratio of these organic aluminum to reactants is 0.01 to 0.5 to aluminum.
Preferably it is 0.05-0.2 (molar ratio). Two or more of these organoaluminiums or reactants of organoaluminum can be used in combination.

The polymerization method may include solution assembly in a hydrocarbon solvent, slurry polymerization in a propylene solvent, etc., but is not limited to these methods.

The ethylene-propylene copolymer in the present invention can be easily pelletized, easily mixed with propylene resin, and uniformly dispersed.

As the polypropylene used in the present invention, a polypropylene homopolymer or a crystalline copolymer containing ethylene, preferably 0 to 20% by weight, preferably 0 to 10% by weight, is used. In particular, polypropylene containing ethylene is preferably used as a bumper composition. At this time, if the ethylene content exceeds 20% by weight, the strength of the polypropylene itself decreases. These polypropylenes are generally in the range of commercially available grades.

In the polypropylene resin composition of the present invention, the composition ratio of the copolymer rubber and polypropylene is 5 to 50 in terms of weight ratio.
150-95, preferably 5-35/65-95. If the copolymer rubber has 5 parts iA: less than 1, the effect of improving the impact resistance of the polypropylene resin composition of the present invention will be small, and if it exceeds 50 parts, there will be problems in terms of cost.

The polypropylene resin composition of the present invention may contain conventional auxiliary additives, such as antioxidants, heat stabilizers, ultraviolet inhibitors, and colorants, as well as calcium carbonate,
Kaolin.

An appropriate amount (usually 0 to 50% by weight) of an agent can also be added.

The polypropylene resin composition obtained by the present invention is prepared by mixing the polypropylene resin, ethylene-propylene copolymer rubber, and optionally auxiliary additive components and fillers, and then using an extruder, a uniter, a Banbury mixer gas, etc. After kneading at a temperature of 160 to 230°C using
Usually pelletized. Temperature 200 using this pellet
The molded product obtained by injection molding at ~300℃ has impact resistance,
Excellent extrusion flowability. When using an injection molding machine that has a crosstalk effect, it is also possible to omit the crosstalk step.

The polypropylene resin composition according to the present invention is used as a material for automobile parts and electrical parts. Moreover, it can be suitably used as a resin composition for blow molding.

Example 1 (1) First, a catalyst was prepared as follows.

A rotor and 3 g of anhydrous magnesium chloride (31.5 m m
ot). Next, add 2-ethylhexyl (di-2-ethylhexyloxy)phosphine oxytro 37FL mot dried using molecular sieves,
It was heated to 80°C and completely dissolved.

After cooling to room temperature, 120 ml of n-hexane was added to obtain a colorless and transparent homogeneous solution. This homogeneous solution was heated to 60°C and 3.5 ml of titanium tetrachloride was added. (31.5m
mol) was added and stirred for several minutes to obtain a yellow transparent homogeneous solution. A mixture of 120 ml of n-hexane and 3Q ml of titanium tetrachloride was gradually added to this solution while stirring, producing a yellow fine powder. After continued stirring for 2 hours, a yellow fine powder solid complex was precipitated, and the supernatant was filtered off. Freshly dried n-hexane 240- was added and stirred for 30 minutes for washing. After repeating this washing operation six times, a yellowish white fine powder solid composite was obtained. N-hexane was added to this solid to make the entire amount into an isom/m slurry.

Analysis of the fine powder solid slurry revealed that it was 0.025 m
It contained ot/t Ti atoms, 0.198 mal/L Mg atoms and 0.0058 mot/L phosphorus atoms.

(2) Polymerization was then carried out as follows.

An autoclave with a capacity of 10 t was sufficiently purged with nitrogen, and 6 t of n-hexane, which had been dried with molecular sieves and degassed, was charged into the autoclave. Then dry ethylene2. OL/11IIIL, propylene 3.5t/
Then, a mixed gas of 0.2 t/yam of hydrogen was added, and the internal pressure was maintained at 5 to 9/d. After adding 6 g of a 1 mot/L n-hexane solution of triimbutylaluminum, 0.151 rLTnDt of the n-hexane slurry of the catalyst component prepared in (1) above was added to initiate polymerization. The temperature was controlled at 90° C., the monomer mixed gas was passed through at the above flow rate, and polymerization was carried out for 1 hour. No gel formation was observed during the polymerization. After 1 hour, methanol 60- was added to stop the polymerization, and a small amount of anti-aging agent was added, followed by steam stripping.
390 g of copolymer rubber was obtained. 1 equivalent of Ti atom 53
．． 9kl? The polymer yield was . Mooney viscosity, propylene content in the copolymer rubber, etc. were measured, and the results are shown in Table 1.

(3) Crosstalk was performed as follows.

The copolymer rubber obtained in the polymerization step (2) and the commercially available polypropylene resin (Mitsubishi Yuka Nofuren BC-4) were mixed in the proportions shown in Table 2 in a polymerization mixer (capacity 1 t, filling rate 70
%.

After kneading at a preheating temperature of 120° C. and a mixing time of 6 minutes), the mixture was formed into a sheet using a roll, and the sheet was cut into square pellets.

(4) Preparation of injection molded products The molding plate and conditions are as follows.

A 6.5 ounce in-line screw type injection molding machine manufactured by Japan Steel Works, Ltd. was used as an injection molding machine, and samples were prepared under the following injection molding conditions.

Injection pressure - Next pressure 500 Ckg/crIL2] Secondary pressure 400 [kg/cfIL2] Injection time - Next pressure 15 seconds at 12th pressure Molding temperature 240°C Cooling temperature (mold temperature) 40°C Cooling time 20 seconds Table 2 shows the characteristics during the above processing. According to Table 2, it is clear that the composition in which the rubber polymerized with the catalyst containing the Ti component of the present invention is blended with polypropylene exhibits good flowability.

Example 2 In Example 1, the amount of ethylene and propylene supplied was changed to 3. OL/th propylene 3, Q 1/
wL and 5-ethylidene-2-norbornene 18d was added to the reaction system over 1 hour at the same time as the start of polymerization. After 1 hour, the mixture was treated in the same manner as in Example 1 to obtain 279 g of copolymer rubber.

This was a yield of 38.8 to 9 per gram of Ti atoms.

Next, a physical property test was conducted in the same manner as in Example 1, and the results are shown in Table 12 and Table 2.

Example 3 N-hexane 6 dehydrated in a 10 L autoclave
2.25 t of ethylene heated to 90℃
WL, 3.25 t/vm of propylene was blown into the autoclave from the bottom, and the internal pressure was increased to 5 kg/cm.
Keep it in G. Next, after adding 4 m mob of diisobutylaluminum monochloride, the Ti prepared in Example 1 was added.
A catalyst was added in an amount of 0.10 rrLmoL in terms of Ti, and polymerization was started. During the polymerization, the above-mentioned ethylene and propylene were blown in and the pressure was maintained at 5 kg/cm''G. After polymerization was carried out for 1 hour, the polymerization was stopped in the same manner as in Example 1.
After treatment, copolymer rubber 216 II was obtained. This is Ti
This corresponds to a yield of 4 s of copolymer rubber per 1 fl, tlcp.

In the same manner as in Example 1, the physical properties of this copolymer rubber itself and the physical properties of a polypropylene resin composition prepared using the copolymer rubber were measured, and the results are shown in Table 19 and Table 2.

Example 4 Polymerization was carried out in the same manner as in Example 3, and 5-
Ethylidene-2-norbornene 181+1/ was added over 1 hour. When treated in the same manner as in Example 1, 174 g of copolymer rubber was obtained. This is 36.3 per Ti l g
This is the yield of Yu.

In the same manner as in Example 1, the physical properties of this copolymer rubber itself,
The physical properties of the polypropylene resin composition prepared using this were measured, and the results are shown in Table 12 and Table 2.

Comparative Example 1 Dehydrated in a fully degassed and dried 10t autoclave
- 6 tons of hexane was added.

VcCj 33.2 mm) t/hr, ethylaluminum sesquichloride 42.0 z mot/hr, dehydrated n-hexane 4 t/hr, ethylene 2.5 t/min, propylene 3,25 t/min, hydrogen 0.11/hr were continuously supplied. The polymerization temperature was controlled at 35° C., and the reaction solution was withdrawn at a constant rate from the lower valve of the autoclave, and polymerization was continued for 8 hours. The reaction solution was steam stripped to obtain a solid rubber. The yield of copolymer rubber per gram of vanadium is 2.4kl! Met. Comparative Example 2 A Ti-based solid catalyst was prepared according to the method of Example 1 of JP-A No. 50-95382. did. The solid catalyst was washed 5 times with 500 d of n-hexane, and the total amount was reduced to 1 by adding n-hexane.
Prepared to ooo m/.

The Mg/Ti molar ratio in this solution is 2. ．． The 02Ti atomic concentration was 0.495 mot/L.

The same operation as in Example 3 was carried out using the above catalyst to copolymerize ethylene and propylene. The yield of copolymer rubber was 233 g. Next, the physical properties of the copolymer rubber were measured in the same manner as in Example 1 and summarized in Table 1. In DSC, the heat of fusion around 120℃ was 2.27 (Ilt19
It can be seen that the crystallinity of the ethylene chain is large.

The physical properties of the polypropylene resin composition were measured in the same manner as in Example 1, and the results are summarized in Table 2. High hardness <,
It can be seen that the MFR value and the Izot impact strength value are smaller than those of the examples.

[Brief explanation of drawings]

The drawing shows the composition of propylene in the ethylene-propylene copolymer rubber in the present invention. 1... Ethylene-propylene copolymer rubber of the present invention, 2... Ethylene-propylene copolymer rubber different from the present invention.

Claims (1)

[Scope of Claims] (1) The ratio of ethylene, propylene and non-conjugated diene is 15 to 70/30 to 8510 to 15 (wt%), (ii) The weight average molecular weight C and the number average molecular weight Mn are The ratio Mw/Mn is 4 to 18, (+m) the heat of fusion in the range of 100 to 140°C by differential thermal analysis is 1 cbt/Ji' or less, (iv
) Propylene content (A weight %) of the low molecular weight portion accounting for 15 weight % of the total copolymer and 15 weight % of the total copolymer.
Ethylene-propylene copolymer, which satisfies the relationship A-B)10 between the propylene content (B weight) of the high molecular weight portion occupying % by weight, and has a structure in which the amount of reversed coupling of ω propylene is 5 mole or less. 5 to 50% by weight of polymerized rubber and ■ 20% of polypropylene homopolymer or ethylene.
A polypropylene resin composition comprising 50 to 95% by weight of a copolymer comprising: