JPH05170988A - Polypropylene-based resin composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition excellent in balance among coating properties, impact resistance, etc., by blending specific amounts of a polypropylene-based resin with a modified polypropylene-based resin, an ethylenic copolymer and a polyfunctional compound. CONSTITUTION:The objective composition is obtained by blending 100 pts.wt. total amount of (A) 5-90wt.% polypropylene-based resin, (B) 90-5wt.% modified polypropylene-based resin prepared by grafting a monomer containing carboxylic acid anhydride group or carboxyl group (preferably acrylic acid, maleic acid, etc.) onto a polypropylene-based resin and (C) 5-40wt.% ethylenic copolymer composed of (i) 40-90wt.% ethylene unit, (ii) 5-60wt.% alkyl alpha,beta-unsaturated carboxylate unit and (iii) 0.3-10wt.% maleic anhydride unit with (D) 0.1-10 pts.wt. polyfunctional compound (e.g. trimethylenediamine or bisphenol A) having two or more functional groups of amino, epoxy, dihydro-oxazolyl and isocyanate in one molecule.

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 having improved paint properties as well as improved balance of physical properties represented by impact resistance and rigidity.

[0002]

2. Description of the Related Art Polypropylene resins are not only low in cost and excellent in moldability, but also have mechanical properties, solvent resistance,
Since it has excellent properties such as oil resistance and chemical resistance, it is widely industrially manufactured and used in various fields as industrial parts such as automobiles, electric and electronic appliances and daily necessities. However, various problems have arisen as the application development of polypropylene resins progresses. One of these problems is that when a polypropylene resin is used as an exterior member that requires painting, the paintability of the molded product is poor because the polypropylene resin is non-polar.
Various attempts have been made to solve this problem. For example, there is a method for improving the paintability by physically or chemically modifying the surface of a molded article. However, this method involves complicated steps and may not be fully effective.

As described above, as a method for improving the coating property of polypropylene resin without complicated steps, for example, JP-A-61-111346 discloses polypropylene resin, unsaturated carboxylic acid anhydride, and unsaturated resin. There has been proposed a method for improving the coatability of a molded article by using a composition obtained by melt-kneading an ethylene copolymer having an ester as a monomer. However, although the composition proposed here certainly improves the coating property, the balance of physical properties represented by impact resistance and rigidity does not satisfy the requirements as an exterior member.

Further, as a method for improving the balance of physical properties of polypropylene resins, Japanese Patent Laid-Open No. 205342/1988 has been proposed.
In the publication, a partially crosslinked polypropylene resin composition comprising an acid-modified polypropylene resin, an acid-modified olefin rubber and diamines and a method for producing the same are proposed. However, although the composition proposed here is certainly improved in the balance of physical properties represented by impact resistance and rigidity, it has not been improved in paintability and must satisfy the requirements as an exterior member. I can't.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is excellent in coating properties and physical properties represented by impact resistance and rigidity, which were not possible with conventional techniques, and satisfies the requirements as an exterior member. A polypropylene resin composition is provided.

[0006]

Therefore, as a result of extensive research, the inventors of the present invention have solved the problem by adding a specific compound to a polypropylene resin, a modified polypropylene resin and an ethylene copolymer. It was That is, the present invention relates to (A) 5 to 90% by weight of polypropylene resin, (B) 90 to 5% by weight of modified polypropylene resin grafted with at least one kind of monomer containing a carboxylic acid anhydride group or a carboxyl group. %, And (C)
Ethylene copolymer consisting of (a) 40 to 90% by weight of ethylene unit, (b) 5 to 60% by weight of α, β unsaturated carboxylic acid alkyl ester unit, and (c) 0.3 to 10% by weight of maleic anhydride unit. 5-40% by weight and (A), (B)
And (C) with respect to 100 parts by weight in total, (D) a polyfunctional compound containing two or more functional groups selected from an amino group, an epoxy group, a dihydrooxazolyl group and an isocyanate group in one molecule. The present invention relates to a polypropylene resin composition comprising 1 to 10 parts by weight and having excellent impact resistance.

Here, as described above, the component (A) and /
Alternatively, a composition comprising the component (B) and the component (C) is known as a polypropylene resin composition having improved impact resistance and coatability. However, the composition obtained by adding the above-mentioned component (D) to the mixture consisting of the components (A), (B) and (C) has the above-mentioned components (A) and / or (B) and (C). The impact resistance can be remarkably improved without impairing other mechanical properties such as rigidity, as compared with the composition comprising the component).

Conventionally, the component (C) has been widely used as an impact modifier for engineering resins, particularly polyamide resins. As a mechanism for developing impact resistance, Poly is used.
mer, 26 , 1855 (1985), which is based on the reaction between the reactive functional group contained in the engineering resin and the acid anhydride group contained in the component (C).

However, the component (A) is originally a non-polar resin and is not a resin that reacts with the reactive group of the component (C).
The component (B) also has very poor reactivity with the component (C). Moreover, the component (C), the component (A) and / or the component (B)
The dispersibility in the components is not so good as to satisfy the above-described impact resistance developing mechanism, and only a certain degree of improvement in impact resistance is achieved.

The component (D), which is indispensable in the present invention, can finely disperse the component (C) in the continuous phase formed by the components (A) and (B), and the impact resistance developing mechanism. Is something that can be achieved. Each constituent component of the composition of the present invention will be described below. The polypropylene-based resin (A) used in the present invention is a propylene homopolymer and / or a propylene copolymer. Here, the propylene copolymer is propylene and ethylene and / or butene-1, pentene-1, 4-
Α selected from 4 to 20 carbon atoms such as methylpentene-1
-Copolymers with olefins, and the like, and block copolymers or random copolymers thereof are used. As the component (A), one type of propylene homopolymer or propylene copolymer may be used, or two or more types may be used in combination.

The compounding amount of the polypropylene resin (A) of the composition of the present invention is 5 to 90% by weight, and further 10 to 10% by weight.
It is preferably 80% by weight. When the blending amount is less than 5% by weight, the blending amount of the component (B) relative to the entire composition is relatively large, so that the composition is inferior in fluidity due to the reaction with the component (D) and inferior in moldability. Becomes When the blending amount exceeds 90% by weight, the blending amount of the component (B) in the entire composition becomes relatively small, so that the dispersibility of the component (C) is not sufficient and the low temperature impact resistance is poor. It becomes a composition.

The modified polypropylene resin (B) of the composition of the present invention means a grafted product of a polypropylene resin with a monomer containing a carboxylic acid anhydride group or a carboxyl group in the presence of a radical generator. A modified polypropylene resin. As the polypropylene resin to be modified, the above-mentioned (A) polypropylene resin can be used.

As the carboxylic acid anhydride group- or carboxyl group-containing monomer used for graft modification, unsaturated acids such as acrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, crotonic acid and isocrotonic acid are used. Examples thereof include carboxylic acids and acid anhydrides of these unsaturated carboxylic acids. Among them, acrylic acid, maleic acid,
Maleic anhydride is preferred. Note that these are 2
You may mix and use a kind or more.

As the radical generator used for the graft modification, dicumyl peroxide, benzoyl peroxide, di-t-butyl peroxide, 2,5-
Organic peroxides such as dimethyl-2,5-di (t-butylperoxy) hexane and 2,5-dimethyl-2,5-di (t-butylperoxy) hexene-3 are preferred. Here, the (B) modified polypropylene resin can be produced by a known method, but as a preferable production method thereof, an extruder, a Banbury mixer, a kneader or the like is used, and the polypropylene resin and the carboxylic acid anhydride are used. Examples thereof include a method in which a monomer containing a group or a carboxyl group and a radical generator are melt-kneaded to produce. The compounding amount of each compound used at this time is not particularly limited and may be selected according to the situation, but it is preferable to select the compounding amount in a range in which the graft addition amount is 0.01 to 10% by weight. It is preferable to select the blending amount within the range in which the graft addition amount is 0.1 to 5% by weight. When the amount of graft addition is less than 0.01% by weight, the effect of finely dispersing the component (C) in the continuous phase is small regardless of the blending amount of the component (D), and impact resistance can be sufficiently improved. Can not. On the other hand, if the graft addition amount exceeds 10% by weight, the effect is less than the graft addition amount, and rather the fluidity of the obtained composition may be impaired.

The compounding amount of the (B) modified polypropylene resin of the composition of the present invention is 90 to 5% by weight, and further 8
It is preferably 0 to 10% by weight. When the blending amount exceeds 90% by weight, the blending amount of the component (B) in the whole composition becomes relatively large, so that the composition is impaired in fluidity and inferior in moldability. When the compounding amount is less than 5% by weight, (B)
Since the blending amount of the components relative to the whole composition is relatively small, the dispersibility of the component (C) is not sufficient, and the composition becomes inferior in low temperature impact resistance.

The ethylene copolymer (C) used in the present invention is composed of (a) an ethylene unit of 40 to 90% by weight, preferably 65 to 90% by weight, and (b) an α, β unsaturated carboxylic acid. An ethylene copolymer comprising 5 to 60% by weight of alkyl ester units, preferably 10 to 35% by weight, and (c) 0.3 to 10% by weight of maleic anhydride units, preferably 1 to 5% by weight.

The monomer component (b) α, β unsaturated carboxylic acid alkyl ester is an unsaturated carboxylic acid having 3 to 8 carbon atoms, for example, acrylic acid, methacrylic acid, etc. As, methyl acrylate,
Examples thereof include ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, and the like. Of these, methyl acrylate, ethyl acrylate, n-butyl acrylate, and methyl methacrylate are particularly preferable.

In addition, within the range where the performance is not impaired,
Ethylene copolymers obtained by copolymerizing other copolymerizable monomer components such as vinyl acetate and vinyl propionate are also included. (C) In the ethylene copolymer,
When the content of the ethylene unit (a) is less than 40% by weight, the resulting composition has a large decrease in rigidity, and when it exceeds 90% by weight, the impact resistance decreases. Further, when the amount of the (b) α, β unsaturated carboxylic acid alkyl ester unit is less than 5% by weight, the effect of improving impact resistance is small, and when it exceeds 60% by weight, the decrease in rigidity becomes large. Further, if the maleic anhydride unit (c) is less than 0.3% by weight, favorable results cannot be obtained in impact resistance, and if it exceeds 10% by weight, fluidity is lowered.

The content of the ethylene copolymer (C) in the composition of the present invention is 5 to 40% by weight, and further 10 to 40% by weight.
It is preferably in the weight%. If the blending amount is less than 5% by weight, the composition becomes inferior in low temperature impact resistance, and the blending amount is 40%.
When the content is more than weight%, the composition is impaired in fluidity and inferior in moldability. (D) an amino group, an epoxy group, and
Examples of polyfunctional compounds containing two or more functional groups selected from a dihydrooxazolyl group and an isocyanate group in one molecule are shown below.

As the polyfunctional compound containing two or more amino groups in one molecule as the component (D), aliphatic diamines such as trimethylenediamine, tetramethylenediamine, hexamethylenediamine, ethylenediaminecarbamate and hexa Aliphatic diamine carbamates such as methylene diamine carbamate, diethylene triamine,
It has aliphatic polyamines such as triethylenetetramine and tetraethylenepentamine, alicyclic polyamines such as menthanediamine and N-aminoethylpiperazine, and aromatic rings such as m-xylylenediamine and tetrachloro-p-xylylenediamine. Aliphatic polyamines and the like can be used.

Examples of the polyfunctional compound containing two or more epoxy groups in the molecule as the component (D) include bisphenols such as bisphenol-A, resorcinol and hydroquinone, and glycidyl ethers of halogenated bisphenols thereof. Can be given. Examples of the polyfunctional compound containing two or more dihydrooxazolyl groups in the molecule as the component (D) include 2,2 ′-(1,3-
Phenylene) -bis (2-oxazoline) and the like.

As the polyfunctional compound containing two or more isocyanate groups in one molecule as the component (D),
4,4'-diphenylmethane diisocyanate, 4,
4'-diphenylethane diisocyanate, 4,4'-
Examples thereof include polyfunctional isocyanate compounds such as diphenylpropane diisocyanate, triisocyanate benzene, and triisocyanate naphthalene. The component (D) is preferably a compound containing two or more functional groups selected from amino groups and isocyanate groups in one molecule.

Among these (D) components, more preferred polyfunctional compounds are aliphatic diamines, aliphatic diamine carbamates, aliphatic diamines having an aromatic ring and diisocyanates. The blending amount of the component (D) in the composition of the present invention is (A), (B) and (C).
Is preferably 0.1 to 10 parts by weight, and more preferably 0.2 to 5 parts by weight. When the blending amount is less than 0.1 part by weight, the dispersibility of the ethylene copolymer (C) is not sufficient and the composition is inferior in low temperature impact resistance. When the compounding amount exceeds 10 parts by weight, the composition becomes inferior in fluidity and moldability.

The polypropylene resin composition of the present invention is
For example, it can be produced by melt-kneading the components (A), (B), (C) and (D). Examples of the melt-kneading device used include known melt-kneading devices such as a twin-screw extruder. The temperature for melting and kneading each component is usually 180.
It is set in the range of 320 ° C. Melt kneading temperature is 180
If the temperature is lower than 0 ° C, the melting of the raw materials will be insufficient and the desired composition will be difficult to obtain. Further, if the temperature is higher than 320 ° C., decomposition of the raw material occurs, which is not preferable.

The kneading order is not particularly limited, and (A),
The components (B), (C) and (D) may be kneaded together, but preferably the melt kneading is divided into two stages, and (A), (B) and (C) are previously melt kneaded in the preceding stage. ,
Then, the method of kneading (D) in the latter stage, or (A),
It is desirable to add (D) during the melt-kneading of (B) and (C).

The polypropylene resin composition of the present invention contains other components such as pigments, dyes, heat stabilizers, antioxidants, weathering agents, nucleating agents, and lubricants as long as the moldability and physical properties are not impaired. , Plasticizers, antistatic agents, other polymers and the like can be added in any manufacturing and molding process.
In addition, the polypropylene-based resin composition of the present invention may be added with an inorganic filler to be described later in any production and molding process as long as the moldability and physical properties thereof are not impaired. Examples of the inorganic filler include iron oxide, alumina,
Oxides such as magnesium oxide and calcium oxide, hydrated metal compounds such as aluminum hydroxide, magnesium hydroxide, basic magnesium carbonate and calcium hydroxide, carbonates such as calcium carbonate and magnesium carbonate, talc, clay and bentonite. Borates such as silicates, barium borate, zinc borate, etc., glass fibers, potassium titanate fibers, metal-coated glass fibers, ceramic fibers, wollastonite, fibrous fillers such as fibrous magnesium oxysulfate, etc. I can give you.

The polypropylene resin composition of the present invention is
It can be easily processed into molded articles of various shapes by any conventionally known molding processing method such as injection molding method and extrusion molding method.

[0028]

EXAMPLES Various physical properties used in Examples and Comparative Examples of the present invention were measured based on the following test methods. (1) Melt flow rate (MFR) Based on ASTM-D1238, it measures at a measurement temperature of 230 ° C. and a load of 2160 g. (2) Izod impact strength The notched Izod impact strength is measured according to ASTM-D256. (3) Flexural modulus Measured according to ASTM-D790. (4) Paintability 150mm x 150mm x 2m molded by injection molding
m test piece, 1,1,1-trichloroethane vapor (7
After surface cleaning in 4 ℃) for 30 seconds and drying at room temperature, urethane paint Retan PG60 (Kansai Paint Co., Ltd.)
Is applied to a thickness of 50 to 70 μm and left at 23 ° C. for 10 minutes. Then, it is dried in an oven at 80 ° C. for 30 minutes to obtain a coated test piece.

The coating film of this test piece had a 1 mm square grid 10
0 cuts are made, cellophane tape is pasted on the cross, and then the cellophane tape is peeled off momentarily, and the paintability is evaluated by the number of the remaining crosses. The components (A), (B), (C) and (D) used in the examples and comparative examples of the present invention are listed below. (A) Polypropylene resin A-1: Propylene homopolymer having MFR of 30 g / min A-2: Propylene-ethylene block copolymer having MFR of 16 g / min and ethylene content of 8% by weight (B) Modified polypropylene resin B-1: Modified polypropylene resin obtained by grafting 0.5% by weight of maleic anhydride onto a propylene / ethylene block copolymer having an MFR of 35 g / min and an ethylene content of 8% by weight B-2: MFR Is a modified polypropylene resin in which 0.5% by weight of maleic anhydride is grafted on a propylene homopolymer of 5.5 g / min (C) ethylene copolymer C-1: the weight ratio of ethylene, ethyl acrylate and maleic anhydride is E /EA/MAH=69.9/27.0/
3.1 ethylene copolymer C-2: the weight ratio of ethylene, ethyl acrylate, maleic anhydride is E / EA / MAH = 66.8 / 32.0 /
1.2 ethylene copolymer (D) polyfunctional compound D-1: trimethylenediamine D-2: 4,4′-diphenylmethane diisocyanate

[0030]

Example 1 (A) polypropylene resin, (B) modified polypropylene resin and (C) ethylene copolymer were mixed in the predetermined amounts shown in Table 1, mixed in a Henschel mixer, and then mixed with a vent in the same direction. Axial extruder (45mm inner diameter,
Melt kneading was carried out at L / D = 30), the polyfunctional compound (D) was added from the middle of the extruder, and further melt kneading to prepare pellets.

The pellets were dried by heating at 80 ° C. for 1 hour, and various physical properties were measured based on the above-mentioned test methods.

[0032]

Examples 2 to 5 The same as Example 1 except that the kneading components and blending amounts are shown in Table 1.

[0033]

[Comparative Examples 1 to 6] The same as Example 1 except that the kneading components and blending amounts are shown in Table 1.

[0034]

[Table 1]

[0035]

EFFECTS OF THE INVENTION According to the present invention, it is possible to obtain a polypropylene resin composition which is excellent not only in coatability but also in balance of physical properties represented by impact resistance and rigidity. Therefore, the composition obtained by the present invention can be suitably used for, for example, automobile bumpers.

Continuation of front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location C08L 33/06 LJC 7921-4J LJD 7921-4J 51/06 LLD 7142-4J LLE 7142-4J

Claims (1)

[Claims] 1. A modified polypropylene resin having (A) 5 to 90% by weight of polypropylene resin and (B) at least one monomer having a carboxylic acid anhydride group or a carboxyl group grafted thereto. %, And (C) (a) ethylene unit 40 to 90% by weight, (b)
α, β unsaturated carboxylic acid alkyl ester unit 5 to 60
Wt% and (c) 5 to 40 wt% of an ethylene copolymer consisting of 0.3 to 10 wt% of maleic anhydride units, and (D) to 100 parts by weight of (A), (B) and (C). ) Excellent impact resistance consisting of 0.1 to 10 parts by weight of a polyfunctional compound containing two or more functional groups selected from an amino group, an epoxy group, a dihydrooxazolyl group and an isocyanate group in one molecule. Polypropylene resin composition.