JPH07207076A - Polypropylene resin composition - Google Patents

Abstract

PURPOSE:To obtain a polypropylene resin composition which has well-balanced rigidity and impact resistance and is capable of giving thin molded articles. CONSTITUTION:The resin composition is prepared by melt mixing preferably 100 pts.wt. of a crystalline polypropylene (A) and preferably 0.1-30 pts.wt. of a condensate (B) of a propylene/alkenylsilane copolymer (a) with a propylene/ ethylene/alkenylsilane copolymer (b), which is obtained by condensation in the presence of a catalyst such as a hydrosilylation catalyst and is soluble in boiling xylene.

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 containing a specific compound and having good physical properties.

[0002]

2. Description of the Related Art Polypropylene has various moldability, has a relatively good balance of physical properties, has excellent electrical, mechanical and chemical properties, and can be obtained at low cost. Is very well used in various fields.

Particularly in recent years, the physical properties such as rigidity, impact resistance, heat distortion resistance, and surface hardness have been further improved due to higher performance of catalysts, progress of polymerization technology, improvement of addition effect of crystallization nucleating agent and the like. Research and improvement have been carried out as excellent ones.

Polypropylene is an inexpensive resin having excellent heat resistance and rigidity, but its crystallinity is relatively small. Therefore, if molded by an ordinary method, the balance between the rigidity and impact resistance of the molded product is the original of the resin. There is a problem that it is inferior to that of the ones, and in order to solve this problem, the molecular weight distribution is changed, the method of mixing polypropylenes having different physical properties or the addition of various nucleating agents to increase the rigidity The method of adding various rubbers to improve impact resistance is
Is generally known.

As a means for improving such physical properties, a method of adding a crosslinked product of alkenylsilane / propylene copolymer by irradiation to polypropylene (Japanese Patent Laid-Open No. 3-33138).
), And a method of adding an alkenylsilane / propylene copolymer to polypropylene and crosslinking it in the presence of a catalyst during melt-kneading (Japanese Patent Laid-Open No. 5-86207).

[0006]

In the method of adding a crosslinked alkenylsilane / propylene copolymer having a large amount of boiling xylene insolubles, it is difficult to sufficiently disperse the additive, and the effect of improving the physical properties is small. Further, although a method of crosslinking an alkenylsilane / propylene copolymer with a catalyst during melt kneading improves both rigidity and impact resistance,
The operation is complicated, and it is difficult to reuse under the condition that the boiling xylene insoluble content is large.

Further, it is easy to improve either rigidity or impact resistance by the conventional method, but it is difficult to improve in a well-balanced manner. For example, in the method of adding a nucleating agent, since the crystallinity of polypropylene only increases, the rigidity increases, but the impact resistance decreases. In addition, in the method of improving impact resistance by adding rubber, there is a problem that impact resistance can be improved because soft rubber is added, but rigidity is reduced, and the balance of physical properties is not always satisfactory. There is a desire to develop other useful compositions.

[0008]

Means for Solving the Problems The inventors of the present invention have made an earnest search for a new composition in which the balance between the rigidity and the impact resistance of polypropylene is improved, and as a result, a composition having excellent physical properties by adding a specific compound has been obtained. The present invention has been completed by finding that a product can be obtained.

That is, the present invention relates to crystalline polypropylene (A), a copolymer of propylene and alkenylsilane (a) soluble in boiling xylene obtained by condensation in the presence of a catalyst, propylene and ethylene. A polypropylene resin composition obtained by melt-mixing a condensate (B) with an alkenylsilane copolymer (b).

The crystalline polypropylene (A) used in the present invention is not only a homopolymer of propylene but also propylene, ethylene and butene-as long as it is crystalline.
Random copolymers and block copolymers with other olefins such as 1, and hexene-1 may be used, and those commercially available in the method for producing polyolefin or those widely available in the market can be used without any trouble. The crystalline polypropylene has a molecular weight of about 0.1 to 10 as an intrinsic viscosity measured with a tetralin solution at 135 ° C. and a content of other olefins of 0 to 50% by weight.

In the production of these crystalline polypropylenes, the catalyst used for polymerization is, for example, a titanium trichloride catalyst or a catalyst component in which a titanium compound such as titanium trichloride or titanium tetrachloride is supported on a magnesium compound, and an alkylaluminum is a promoter. A carrier catalyst as a component is used. Furthermore, a catalyst composed of a metal complex of a group 3 or 4 of the periodic table having a cyclopentadienyl compound represented by a combination of dicyclopentadienyl zirconium dichloride and an aluminoxane and an aluminoxane compound, or A homogeneous catalyst using a metal cation complex of Groups 3 and 4 of the Periodic Table having a cyclopentadienyl compound as a ligand can also be used.

As the polymerization method, a conventional method such as a solvent polymerization method, a bulk polymerization method in which substantially no solvent is present, or a gas phase polymerization method can be used, and the polymerization conditions are not particularly limited, and the reaction temperature is usually room temperature. ~ 200 ℃, normal pressure ~ 50kg
/ Is carried out in cm ^2.

The alkenylsilane of the copolymer (a) of propylene and alkenylsilane and the copolymer (b) of propylene, ethylene and alkenylsilane used in the present invention are those having at least one Si-H bond. Preferably used, for example, a compound represented by the following general formula (Formula 1),

[0014]

Embedded image H ₂ C═CH— (CH ₂ ) _n —SiH _p R _3-p (where n is 0 to 12, p is 1 to 3 and R is a hydrocarbon residue having 1 to 12 carbon atoms) Is a halogen.) Specifically, vinylsilane, allylsilane, butenylsilane, pentenylsilane, hexenylmethylsilane, allyldimethylsilane or a compound in which H of some Si—H bonds of these monomers is replaced with halogen, etc. Can be illustrated.

The alkenylsilane copolymers (a) and (b) used in the present invention can be produced by the same method as the above-mentioned method for producing crystalline polypropylene.

There is no particular limitation on the polymerization ratio of the alkenylsilane in the alkenylsilane copolymers (a) and (b), but a concentration that does not cause gelation due to the condensation reaction is good, and usually alkenylsilane is 0.001%. ~ 1.0 wt
%, Preferably 0.005 to 0.1 wt%. When the concentration is higher than this range, gelation is likely to occur during the condensation reaction, and when added to polypropylene for use, the dispersibility during melting deteriorates and the effect of improving the physical properties is small. Moreover, when the concentration is low, the condensation reaction is difficult to proceed.

The proportion of ethylene in the copolymer (b) of propylene, ethylene and alkenylsilane is not particularly limited, but is usually about 10 to 90 mol%, preferably 20 to 80 mol%. .

Alkenylsilane copolymer (a),
The molecular weight of (b) is not particularly limited, and the molecular weight is determined according to the purpose. In terms of mixing with polypropylene, a relatively low molecular weight is better, usually 135 ° C.
In general, the limiting viscosity number measured with the tetralin solution is about 0.1 to 5, particularly preferably about 0.5 to 3.0.

Graft copolymers obtained by graft-polymerizing alkenylsilane onto polypropylene or propylene / ethylene copolymers can also be used for the purpose of the present invention. In that case, the method of grafting the alkenylsilane onto the polypropylene or the propylene / ethylene copolymer is not particularly limited, and the method and conditions used for ordinary graft copolymerization can be used. Usually, the polypropylene or propylene / ethylene copolymer used and the alkenylsilane can be easily graft-copolymerized by heating the alkenylsilane in the presence of a radical initiator such as peroxide at a temperature not lower than the decomposition temperature of the radical initiator.

The condensate of the propylene / alkenylsilane copolymer (a) and the propylene / ethylene / alkenylsilane copolymer (b) used in the present invention is
It is obtained by a method of dissolving both copolymers in an organic solvent and contacting them with a catalyst, or a method of mixing both copolymers and a catalyst and contacting them in an extruder.

In the present invention, the condensation means a reaction in which a copolymer (a) of propylene and alkenylsilane and a copolymer (b) of propylene, ethylene and alkenylsilane are combined by a dehydrogenation reaction by the action of a catalyst. As expected.

The catalyst used for condensation is not particularly limited, and a hydrosilylation catalyst or the like can be used. For example, rhodium chloride cyclooctadiene complex, rhodium salt such as triphenylphosphine complex, platinum iodide,
Platinum bromide, chloroplatinic acid, a benzonitrile complex of platinum chloride, or an alkoxy compound of a Group IVB metal of the periodic table represented by the following general formula (Formula 2) such as a titanate ester.

[0023]

Embedded image R ¹ _n M (OR ² ) _4-n (wherein R ¹ and R ² are the same or different hydrocarbon residues having 1 to 12 carbon atoms, n is an integer of 0 to 3 and M is titanium). , A metal selected from zirconium and hafnium.).

The organic solvent used for the condensation varies depending on the catalyst used, but is usually an aromatic solvent such as benzene, toluene, xylene, chlorobenzene or dichlorobenzene, or an aliphatic solvent such as pentane, hexane, heptane or octane. A solvent is used.

When the reaction is carried out in an organic solvent, the condensation reaction is carried out at 70 ° C. to 200 ° C. for 0.5 to 20 hours with stirring. When the reaction is carried out in an extruder, the kneading is performed for 0.1 to 10 minutes in a molten state by heating at a temperature of the melting point of the copolymer to 300 ° C.

The ratio of condensation between the copolymer (a) of propylene and alkenylsilane and the copolymer (b) of propylene, ethylene and alkenylsilane is usually the same as that of the copolymer (a) of propylene and alkenylsilane. 20-80% by weight
The copolymer (b) of propylene, ethylene and alkenylsilane is 80 to 20% by weight.

The amount of the catalyst used is such that the catalyst concentration in the whole mixture is about 0.01-10000 ppm, preferably 0.1-1000.
It is generally set to ppm.

In the present invention, the condensate soluble in boiling xylene means about 0.5 g of the condensate put in a 500-mesh wire net and the concentration when the condensate is completely dissolved is about 3 g / l. When xylene is used to extract in boiling xylene for 6 hours, the extraction residue is 5 wt% or less, preferably 1 wt%
% Or less, and particularly preferably less than 0.01 wt% for applications where the surface condition becomes a problem.

The compounding ratio of the condensate (B) of the copolymer (a) of propylene and alkenylsilane and the copolymer (b) of propylene, ethylene and alkenylsilane to the crystalline polypropylene (A) is crystalline. 0.1 parts by weight or more based on 100 parts by weight of polypropylene. If the amount is less than 0.1 part by weight, the effect of improving the physical properties is small. Also,
There is no particular upper limit for the use, but it is up to about 30 parts by weight for the purpose of improving the physical properties.

To the composition of the present invention, various additives usually added to polypropylene, such as stabilizers, ultraviolet absorbers, lubricants, surfactants and fillers, can be added.

In the present invention, the method of mixing the above-mentioned respective components is not particularly limited, and the respective components are simply mixed in advance with a tumbler, a Henschel mixer or the like, and then a polypropylene is prepared by using a melt-kneading device such as an extruder or a Banbury mixer. The melting and kneading may be performed at a temperature equal to or higher than the melting point, generally, the melting point to 280 ° C.

[0032]

The present invention will be further described with reference to the following examples.

Example 1 (Preparation of catalyst) A vibration mill equipped with four grinding pots having an inner volume of 4 liters and containing 9 kg of hard balls having a diameter of 12 mm was prepared. Magnesium chloride 300 in each pot under nitrogen atmosphere
g, diisobutyl phthalate 112 ml and titanium tetrachloride 60
ml was added and crushed for 40 hours. 300 g of the crushed material thus obtained
Was placed in a 5 liter flask, 3 liters of toluene was added, the mixture was stirred at 110 ° C. for 30 minutes, and the supernatant was removed. Toluene (3 liters) was added again, the mixture was treated at 80 ° C. for 30 minutes, and the supernatant was removed. Then, the solid content was repeatedly washed with n-hexane to obtain a transition metal catalyst slurry. Titanium was found to be 2.2 wt% when a part was sampled and titanium was analyzed.

(Copolymerization reaction of propylene and vinylsilane) In an autoclave having an internal volume of 5 liters, 40 ml of toluene, 20 mg of the above transition metal catalyst, 0.1 ml of cyclohexylmethyldimethoxysilane and 1.0 ml of triethylaluminum were placed in an autoclave, and 1.5 kg of propylene and vinylsilane were added.
After 1.5 g was added and 18 N liters of hydrogen was injected under pressure, polymerization was carried out at 60 ° C. for 2 hours. After the polymerization, unreacted propylene was purged, the powder was taken out, and then filtered and dried to obtain 630 g of a copolymer.

The intrinsic viscosity (hereinafter referred to as [η]) of this polymer measured in a tetralin solution at 135 ° C. is 1.00.
Met. The melting point and crystallization temperature were measured as the maximum peak temperature by raising or lowering the temperature at 10 ° C / min using a differential thermal analyzer. The melting point was 160 ° C and the crystallization temperature was 1 ° C.
It was 21 ° C. When the silicon content was measured by fluorescent X-ray and converted into the vinylsilane content, it contained 0.04 wt% of vinylsilane unit.

(Copolymerization reaction of propylene, ethylene and vinylsilane) In an autoclave having an internal volume of 5 liters, 40 ml of toluene, 20 mg of the above transition metal catalyst, 0.1 ml of cyclohexylmethyldimethoxysilane and 1.0 ml of triethylaluminum were placed in a nitrogen atmosphere, and 1.5 kg of propylene was added. After adding 2.5g of vinylsilane and press-fitting 18N liter of hydrogen,
Polymerization was carried out at 60 ° C. for 10 minutes while constantly applying an ethylene pressure of 5 kg / cm ² . After the polymerization, unreacted gas was purged, the powder was taken out, and then filtered and dried to obtain 210 g of a copolymer.

The [η] of this polymer was 1.85.
In addition, when the silicon content was measured by fluorescent X-ray and converted into the vinylsilane content, the vinylsilane unit was 0.065.
It contained wt%. The ethylene content calculated from the infrared absorption spectrum was 29.6 wt%.

(Condensation Reaction between Propylene / Vinylsilane Copolymer and Propylene / Ethylene / Vinylsilane Copolymer) 50 g of the propylene / vinylsilane copolymer thus obtained and propylene / ethylene / vinylsilane copolymer 50
g was heated and dissolved in 1.7 liters of toluene, 100 mg of chlorotris (triphenylphosphine) rhodium was added, and the mixture was refluxed for 2 hours. After completion of the reaction, methanol 500
Add 9 ml to precipitate the polymer, filter and dry it to condensate 99.2
g was obtained.

The obtained condensate [η] is 1.79 and G
The molecular weight distribution Mw / Mn measured by PC was 7.8. Also, [η] and the molecular weight distribution of the mixture of the same weight of the propylene / vinylsilane copolymer and the propylene / ethylene / vinylsilane copolymer were 1.43 and 5.5, respectively, and it was confirmed that the condensation reaction occurred. It was The ratio of insoluble matter when extracted with boiling xylene for 6 hours is 0.00
It was 1 wt%.

(Evaluation of Additive Properties of Condensate to Block Copolymer) A block copolymer of propylene and ethylene having an ethylene content of 6.6 wt% and a melt flow index of 8.0 (g / 10 min) (Mitsui Toatsu BJH manufactured by Kagaku Co., Ltd.
H) 5 parts by weight of the above condensate, 0.1 parts by weight of antioxidant, and 0.1 parts by weight of calcium stearate were added to 100 parts by weight of H), and the mixture was heated and mixed at 230 ° C. in an extruder to obtain pellets. Injection molding machine (FKS manufactured by Komatsu Ltd.)
55T) and molded into a test piece for measuring physical properties, and the physical properties were measured. The results are shown in Table 1.

The physical properties were measured according to the following methods. Flexural modulus: ASTM-D-790 Flexural rigidity: ASTM-D-747 Tensile yield strength: ASTM-D-638 Izod impact strength: ASTM-D-256 (with notch) Elongation: ASTM-D-638

Comparative Example 1 Physical properties were measured in the same manner as in Example 1 except that the condensate was not added. The results are shown in Table 1.

Example 2 Instead of the block copolymer of propylene and ethylene (BJHH manufactured by Mitsui Toatsu Chemicals, Inc.), the ethylene content was 11.0.
Example 1 except that a propylene / ethylene block copolymer (BJ4H, manufactured by Mitsui Toatsu Chemicals, Inc.) having a wt% and a melt flow index of 25.7 (g / 10 min) was used.
The physical properties were measured in the same manner as. The results are shown in Table 1.

Comparative Example 2 Physical properties were measured in the same manner as in Example 2 except that the condensate was not added. The results are shown in Table 1.

[0045]

[Table 1]

[0046]

EFFECTS OF THE INVENTION The composition of the present invention has an excellent balance of rigidity and impact resistance as compared with hitherto known compositions, and it is possible to reduce the thickness of molded products, which is extremely industrially valuable.

Claims (3)

[Claims] 1. A crystalline polypropylene (A), a copolymer of propylene and alkenylsilane (a) soluble in boiling xylene obtained by condensation in the presence of a catalyst, and propylene, ethylene and alkenylsilane. A polypropylene resin composition obtained by melt-mixing a condensate (B) with a copolymer (b). 2. The proportion of the copolymer (a) of propylene and alkenylsilane and the copolymer (b) of propylene, ethylene and alkenylsilane is such that the copolymer (a) is 20 to 80% by weight.
The polypropylene resin composition according to claim 1, wherein the copolymer (b) is from 80 to 20% by weight. 3. A copolymer (a) of propylene and an alkenylsilane, which is soluble in boiling xylene obtained by condensation of 100 parts by weight of crystalline polypropylene (A) in the presence of a catalyst, and propylene. The polypropylene resin composition according to claim 1, wherein the condensate (B) of the copolymer (b) of ethylene and alkenylsilane is 0.1 to 30 parts by weight.