JPH0425975B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a resin composition with excellent paintability and impact resistance. More specifically, the present invention relates to a polypropylene resin composition having high flexural modulus and high impact resistance, with improved paintability by using a specific ethylene-α-olefin copolymer rubber with crystalline polypropylene. BACKGROUND ART Conventionally, polypropylene has been widely produced industrially and used in many ways as a general-purpose resin. Polypropylene is a non-polar, chemically extremely inert polymeric substance that does not have polar groups in its molecules. Furthermore, it has high crystallinity and low solubility in solvents, so it is used in areas that require painting, such as automobile bumpers. When used, special pretreatment or addition of additives is employed. In particular, in order to improve the impact resistance and paintability of polypropylene, ethylene-
Addition of α-olefin copolymer rubber is generally performed. Problems to be solved by the invention However, polypropylene has ethylene-α-
By adding olefin copolymer rubber,
The paintability of the polypropylene can be improved, but at present the paintability is sufficient with the pellet-shaped ethylene-α-olefin copolymer rubber with a narrow molecular weight distribution and high ethylene content that is commercially available for the modification. In order to obtain this, it is necessary to add more of the copolymer rubber, and the resulting polypropylene resin composition has low-temperature impact resistance at the same time, but the flexural modulus is extremely reduced and the polypropylene resin composition is This results in the loss of advantages. The present invention has been made against the background of these problems in the conventional technology, and aims to obtain a resin composition that achieves both the contradictory properties of paintability and flexural modulus and has excellent impact resistance. . Means for Solving the Problem That is, the present invention provides crystalline polypropylene resin.
100 parts by weight and 5 to 70 parts by weight of ethylene-α-olefin copolymer rubber, and the ethylene-α-olefin copolymer rubber is composed of copolymer rubbers a and b below, and copolymer rubber a and The resin composition is characterized in that the weight ratio (a/b) with b is 10/90 to 95/5. (a) The ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) Mw/Mn is 4.5 to 15.0, and the iodine value is 0.
~40, ethylene content 50-80% by weight and Mooney viscosity (ML ₁₊₄ , 100°C) 20-110. (b) The ratio of weight average molecular weight (Mw) to number average molecular weight (Mn), Mw/Mn, is less than 4.5, and the iodine value is 0.
~40, ethylene content 20-60% by weight and Mooney viscosity (ML ₁₊₄ , 100°C) 10-110. The crystalline polypropylene resin used in the present invention (hereinafter sometimes referred to as "polypropylene resin") is a propylene homopolymer obtained by homopolymerizing polypropylene using a so-called Ziegler-Natsuta catalyst, or a propylene homopolymer obtained by homopolymerizing polypropylene with a small amount of propylene. of ethylene or α- having 4 to 12 carbon atoms
It is a copolymer of propylene and ethylene or α-olefin obtained by copolymerizing with olefin. When the polypropylene resin is a copolymer, the copolymerization ratio of ethylene or α-olefin in the copolymer is 3 to 20
% by weight, and may be a random copolymer or a block copolymer. The melt flow rate of the polypropylene resin is 0.3 to 80 g/10 min (230°C), preferably 1.2 to 50
g/10min (230°C). In carrying out the present invention, these polypropylene resins may be used alone or in combination of two or more. On the other hand, the ethylene-α-olefin copolymer rubber (hereinafter sometimes referred to as “copolymer rubber”) used in the present invention is a mixture of ethylene, α-olefin and/or non-conjugated diene using, for example, a Ziegler catalyst. The α-olefin used as a copolymerization monomer of such a copolymer rubber is obtained by copolymerizing α-olefin having 3 to 12 carbon atoms.
-Olefins, specific examples of which include propylene, butene-1,4-methylpentene-1, and octene-1. Preferred is propylene. These α-olefins can be used alone or in combination of two or more. It is also possible to copolymerize a non-conjugated diene with the copolymer rubber used in the resin composition of the present invention, and such dienes include the following compounds. Dicyclopentadiene, tricyclopentadiene, 5-methyl-2,5-norbornadiene, 5
-methylene-2-norbornene, 5-ethylidene-2-norbornene, 5-isopropylidene-2
-Norbornene, 5-isopropenyl-2-norbornene, 5-(1-butenyl)-2-norbornene, cyclooctadiene, vinylcyclohexene, 1,5,9-cyclododecatriene, 6-methyl-4,7,8 , 9-tetrahydroindene,
2,2'-dicyclopentenyl, trans-1,2
-divinylcyclobutane, 1,4-hexadiene, 1,6-octadiene, 1,6-octadiene, 1,7-octadiene, 1,8-nonadiene, 1,9-decadiene, 3,6-dimethyl-
1,7-octadiene, 4,5-dimethyl-1,
7-octadiene, 1,4,7-octatriene, 5-methyl-1,8-nonadiene. Among these non-conjugated dienes, 5-ethylidene-2-norbornene (ENB) and/or dicyclopentadiene (DCP) are particularly preferred. The copolymer rubber is composed of copolymer rubbers a and b as described later, and the resin composition of the present invention contains 100 parts by weight of the polypropylene resin and 5 to 70 parts by weight, preferably 10 to 60 parts by weight of the copolymer rubber. It consists of two parts. If the amount of copolymer rubber is less than 5 parts by weight per 100 parts by weight of polypropylene resin, the resulting resin composition will have insufficient paintability and impact resistance;
If it exceeds 70 parts by weight, the flexural modulus becomes low, which is not preferable. The resin composition of the present invention as described above is composed of a polypropylene resin and a copolymer rubber, and the copolymer rubber is composed of specific copolymer rubbers a and b described in detail below in a specific ratio. There is. That is, copolymer rubber a has a weight average molecular weight (Mw) to a number average molecular weight (Mn) ratio Mw/Mn.
4.5-15.0, preferably 4.5-10.0, iodine value 0-
40, preferably from 0 to 30, ethylene content from 50 to 80% by weight, preferably from 60 to 80% by weight and Mooney viscosity (ML ₁₊₄ , 100°C) from 20 to 110, preferably from 20 to
It is 50. If Mw/Mn of copolymer rubber a is less than about 4.5,
The effect of improving paintability is not sufficient, and on the other hand, if it exceeds about 15.0, the low molecular weight components in the copolymer rubber may bleed onto the surface of the molded product, impairing the appearance of the molded product. If the iodine value of the copolymer rubber a exceeds about 40, the heat resistance and weather resistance will deteriorate, and the resulting resin composition may become discolored or cracked. Furthermore, if the ethylene content (ethylene/α-olefin) of copolymer rubber a is less than about 50, the resulting resin composition will have insufficient flexural modulus, while if it exceeds about 80, the effect of improving impact resistance will not be sufficient. . Furthermore, the Mooney viscosity of copolymer rubber a is approximately 20.
If it is less than about 110, mechanical strength such as tensile strength of the resulting resin composition will decrease, while if it exceeds about 110, problems will occur in processability such as a decrease in extrusion flowability during molding such as injection molding. Copolymer rubber a has an undissolved amount of about 10 to 10% when dissolved in cyclohexane at 30°C
Preferably it is 40% by weight. That is, it is better for the adhesive strength of the coating to be improved if the cyclohexane-insoluble content in the copolymer rubber a is somewhat warm than if it is completely absent. Next, copolymer rubber b has a weight average molecular weight (Mw) and a number average molecular weight (Mn) ratio Mw/Mn.
Less than 4.5, preferably 2.0 or more, iodine value 0-40,
preferably 0-10, ethylene content 20-60% by weight, preferably 40-60% and Mooney viscosity (ML ₁₊₄ , 100°C) 10-110, preferably 10-50
It is. Copolymer rubber b with Mw/Mn of less than about 2.0 is difficult to obtain in terms of production, and with Mw/Mn of 4.5 or more, the flexural modulus becomes low. If the iodine value of the copolymer rubber b exceeds about 40, the heat resistance and weather resistance will deteriorate, and the resulting resin composition may become discolored or cracked. Further, if the ethylene content (ethylene/α-olefin) of copolymer rubber b is less than about 20, the resulting resin composition will have insufficient flexural modulus, while if it exceeds about 60, the effect of improving impact resistance will be insufficient. Furthermore, the Mooney viscosity of copolymer rubber b is about 10.
If it is less than about 110, mechanical strength such as tensile strength of the resulting resin composition will decrease, while if it exceeds about 110, problems will arise in processability such as a decrease in extrusion flowability during molding such as injection molding. Next, the copolymer rubber is composed of copolymer rubbers a and b, and the weight ratio (a/b) of a and b is 10/90 to 95/5, preferably
It is 10/90 to 60/40. If the a/b ratio is less than about 10/90, the paintability of the resulting resin composition will not be improved, while if it exceeds about 95/5, the effect of improving impact resistance will not be sufficient. As mentioned above, the copolymer rubber used in the resin composition of the present invention is composed of specific copolymer rubbers a and b in a specific ratio, as described above,
The resin composition obtained in this way has improved paintability, high flexural modulus, and high impact resistance.Although the theoretical reason for this is not clear, it has the effect of improving paintability of copolymer rubber a. and copolymer rubber b
It is considered that the impact resistance improving effects of the two are synergistically expressed without being impaired by the mixed use of the two. Note that the copolymer rubber can be obtained by the following manufacturing method. That is, as the catalyst component used in the production of the copolymer rubber, a catalyst consisting of a combination of a vanadium compound and/or a titanium compound and an organometallic compound of a metal of Groups 1 to 10 of the periodic table is used. As the vanadium compound, a trivalent to pentavalent vanadium compound soluble in an inert organic solvent is used. As the vanadium compound, vanadium halides, oxyhalides, chelate complexes with oxygen-containing compounds, vanadate esters, and the like are preferable. Specific examples of these compounds include vanadium tetrachloride, vanadium oxytrichloride, vanadium trisacetylacetonate, vanadate triethoxide, vanadate tri-n-butoxide, vanadate di-n-butoxy monochloride,
Examples include vanadate ethoxy dichloride, a reaction product of vanadium tetrachloride or vanadium oxytrichloride and alcohol, and the like. These can be used alone or in combination of two or more. More preferred among these compounds are vanadium tetrachloride, vanadium oxytrichloride, and reaction products of these vanadium compounds and alcohols. As the titanium compound, a solid or dissolved titanium trichloride catalyst, a titanium trichloride or a titanium tetrachloride catalyst supported on magnesium chloride are used. Preferably it is a vanadium compound. Examples of organometallic compounds of metals in Groups ~ of the periodic table include organolithium compounds, organozinc compounds,
Mention may be made of organomagnesium compounds and organoaluminium compounds. Among these, organoaluminum compounds are particularly preferred. Examples of organoaluminum compounds include triethylaluminum, tri-n-propylaluminum, tri-isopropylaluminum, tri-n-
-butylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-
n-octyl aluminum, tri-n-decyl aluminum, tri-n-dodecyl aluminum,
diethyl monochloraluminum, dibutyl monochloraluminum, di-n-hexyl monochloraluminum, di-n-octyl monochloraluminum, ethylaluminum sesquichloride, n-butylaluminum sesquichloride, ethylaluminum dichloride, n-butylaluminum dichloride, isobutylaluminum dichloride, n-hexylaluminum dichloride,
Examples include n-octylaluminum dichloride. Reactants of these organoaluminiums and alcohols, amines, etc. can also be used. For example, methanol, ethanol, n-butanol, isobutanol, t-butanol, n-hexanol, n-octanol, 2-ethyl-hexanol, n-decanol, triethylamine, tri-n-propylamine, tri-n-butylamine, tri- -isobutylamine, tri-n-
Hexylamine, tri-n-octylamine, tri-2-ethylhexylamine, diethylamine, di-n-butylamine, di-isobutylamine, di-n-octylamine, di-2-ethylhexylamine, ethylamine, n-propylamine , n-butylamine, isobutylamine, 2-
Such as ethylhexylamine. The ratio of these organic aluminum to the reactant is 0.01 to 0.5, preferably 0.05 to 0.2 (molar ratio) to aluminum. Two or more of these organoaluminiums or reactants of organoaluminiums can be used in combination. Copolymer rubber a is obtained under conditions in which the ratio of the organoaluminum compound/vanadium compound is adjusted to be low. As a specific example of this, for example,
Examples 12 and 13 of Publication No.-7449 are mentioned. Further, copolymer rubber b can be obtained by adjusting the ratio of organoaluminum compound/vanadium compound to be higher than the conditions for copolymer rubber a. The resin composition of the present invention can be manufactured by a commonly used method of mixing a polypropylene resin and a copolymer rubber. For example, the polypropylene resin and copolymer rubber used in the present invention may be mixed using an extruder, kneader blender, Banbury mixer, etc., or an arbitrary amount of polypropylene resin may be added to the copolymer rubber according to preference using a Banbury mixer, kneader blender, etc. to form pellets using a commonly used method, and finally add the pellets and polypropylene resin so that the ratio of polypropylene resin and copolymer rubber falls within the range of the present invention to obtain a molded product. There is a method. The resin composition of the present invention includes conventional auxiliary additive components,
For example, antioxidants, heat stabilizers, ultraviolet absorbers, colorants, etc. can also be added. In addition, fillers such as calcium carbonate, kaolin, talc, asbestos, and glass fiber, olefin-based (co)polymer rubbers other than the copolymer rubber used in the present invention (e.g.
EPR, ethylene-butene copolymer, polyisobutylene, etc.), polyethylene resin, polystyrene resin, acrylonitrile-butadiene-styrene copolymer resin, ethylene-vinyl acetate copolymer resin,
Rubbers and resins such as polybutadiene resin can also be blended, and the amount added is preferably 0 to 30 parts by weight per 100 parts by weight of the resin composition of the present invention. Function As described above, in the resin composition of the present invention, by blending the copolymer rubber consisting of copolymer rubbers a and b with the polypropylene resin, copolymer rubber a has a more excellent paintability improving effect, and Copolymer rubber b has the effect of providing a more excellent effect of improving impact resistance. EXAMPLES The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited to the following Examples unless the gist thereof is exceeded. The various measurement methods are as follows. Molecular weight distribution (Mw/Mn) was determined using gel permeation chromatography (GPC).
Measured under the conditions described in Publication No. 55-7449. Ethylene content was measured by infrared absorption spectrum. Mooney viscosity (ML ₁₊₄ , 100℃) is JIS
According to K6300, preheating for 1 minute, measurement for 4 minutes, temperature 100℃
Measured in. Cyclohexane insoluble amount is 0.3g of raw rubber
Cut it so that the length of each side is 1 mm or less,
Soak in 100ml cyclohexane and incubate at 30℃ for 48 hours.
Leave to stand for an hour, then filter through an 80-mesh stainless steel wire mesh, dry the insoluble matter in vacuum at 105°C, weigh it, and divide the weight of the insoluble matter by the weight of the raw rubber to calculate the amount of cyclohexane insoluble matter (weight %). The melt flow rate (hereinafter referred to as "MFR") of the resin composition is measured according to JIS K7210. Flexural modulus was measured according to JIS K7203. Izotsu impact strength (with notch) is JIS
Measured according to K7110. Paintability (adhesive strength) was determined by exposing a test piece of the resin composition obtained by injection to Tri-Clene vapor twice for 30 seconds, and applying a primer (Japanese Manufactured by B Chemical Co., Ltd., product name: RB-291H) with a thickness of 5
After spraying to a thickness of ~10 microns and drying at 90℃ for 20 minutes, apply urethane paint (manufactured by Nippon B Chemical Co., Ltd., trade name: R-263) as a top coat.
Spray to a thickness of 40 to 45 microns and heat at 90℃ for 40
After drying for a minute and leaving it at room temperature for a day, make a 1cm wide cut on the coating surface and remove the coating for 30 minutes.
The tensile peel strength was measured at a rate of mm/min, and the tensile peel strength of this coating film was measured as the adhesive strength of the coating film. Examples 1 to 6, Comparative Examples 1 to 5 Crystalline polypropylene resin (density: 0.90 g/
cc, MFR; 8.5g/10min, hereinafter abbreviated as "PP") to 100 parts by weight of ethylene-α-olefin copolymer rubber (hereinafter abbreviated as "EPR") in the amount shown in Table 1. Kneading was carried out for 5 minutes in a Banbury mixer of capacity 4. The temperature of the resin composition after discharge was 180 to 200°C. The resin composition taken out from the Banbury mixer was formed into a sheet using a 10-inch roll, and then square pellets were produced using a sheet pelletizer. The obtained square pellets
Flat test pieces (2
× 100 × 120 mm), flexural modulus, and Izot impact strength test specimens were prepared and various measurements were performed. The results are shown in Table 1. As is clear from Table 1, Examples 1 to 3 are as follows:
A variable of EPR(a)/EPR(b),
Comparative Examples 1 and 2 are cases where EPRa and b are single. Examples 1 to 3 have better impact resistance than Comparative Example 1, almost no change in paintability, and better paintability and flexural modulus than Comparative Example 2. Next, Examples 4 and 5 are cases in which the amount of EPR is changed, and Example 6 is an example in which the ethylene content of EPRa is changed. Both have excellent physical properties and paintability. In contrast, Comparative Example 3 is an example in which the ethylene content of EPRb is too high, resulting in poor impact resistance. In addition, Comparative Examples 4 and 5 are EPR
a has a small molecular weight distribution (Mw/Mn)
This is an example using EPR, which has poor paintability.

【table】

[Table] Effects of the Invention As described above, the resin composition of the present invention has good paintability, high impact resistance, and high flexural modulus by blending a specific copolymer rubber with polypropylene resin. There is. Therefore, the resin composition of the present invention is suitable for automobile bumpers, but also for other automobile interior parts, exterior parts, electric wires, electric appliances, housing materials such as electrical equipment, various electrical related parts, films,
Can be used for laminated films, sheet materials, etc.

Claims (1)

[Scope of Claims] 1. 100 parts by weight of crystalline polypropylene resin and ethylene-α-olefin copolymer rubber 5-
70 parts by weight, and the ethylene-α-
Olefin-based copolymer rubber is the following copolymer rubber a
and b, and the weight ratio (a/b) of copolymer rubbers a and b is 10/90 to 95/5. (a) The ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) Mw/Mn is 4.5 to 15.0, and the iodine value is 0.
~40, ethylene content 50-80% by weight and Mooney viscosity (ML ₁₊₄ , 100°C) 20-110. (b) The ratio of weight average molecular weight (Mw) to number average molecular weight (Mn), Mw/Mn, is less than 4.5, and the iodine value is 0.
~40, ethylene content 20-60% by weight and Mooney viscosity (ML ₁₊₄ , 100°C) 10-110. 2 Crystalline polypropylene resin contains ethylene and/or α-olefin having 4 to 12 carbon atoms
The resin composition according to claim 1, which is obtained by copolymerizing 20% by weight. 3 Ethylene content of copolymer rubber (a) is 60 to 80
% by weight of the resin composition according to claim 1. 4 Mooney viscosity of copolymer rubber (a) is 20 to 50
The resin composition according to claim 1. 5. The resin composition according to claim 1, wherein the amount of insoluble matter when the copolymer rubber (a) is dissolved in cyclohexane is 10 to 40% by weight. 6. The resin composition according to claim 1, wherein the copolymer rubber (b) has an iodine value of 0 to 10. 7 Mooney viscosity of copolymer rubber (b) is 10 to 50
The resin composition according to claim 1.