JPH07137076A - Injection molded product improved in heat resistance - Google Patents

Abstract

PURPOSE:To obtain a polypropylene resin molded product excellent in heat resistance by the injection molding of a compsn. consisting of a crystalline polypropylene resin prescribed in melt flow rate and ethylene content and a specific amt. of an aliphatic, alicyclic or aromatic dibasic acid type diamide compd. CONSTITUTION:A propylene/ethylene block copolymer to be used contains 2-15wt.% of ethylene and has a melt flow rate of 1-80g/10min. A compsn. prepared by adding 0.005-5 pts.wt. of an aliphatic, alicyclic or aromatic dibasic acid type diamide compd. to 100 pts.wt. of the block copolymer is subjected to injection molding. By this method, a molded product high in thermal deformation temp. and impact strength at the normal temp. and low temp. can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polypropylene resin injection-molded article having improved heat resistance, and particularly to a polypropylene resin injection-molded article having excellent heat resistance and impact resistance such as automobile parts and home appliance parts. Regarding

[0002]

2. Description of the Related Art Normally, polypropylene resins used for interior materials of automobiles, engine parts such as batteries, and home electric appliances manufactured by injection molding of polypropylene resins are excellent in heat resistance and impact resistance. Due to the need, ethylene-propylene block copolymers are commonly used. However, since the heat resistance is insufficient, a method of adding a crystal nucleating agent (nucleating agent) to the resin to improve the heat resistance is used. For this purpose, p
Aluminum t-butylbenzoate, carboxylic acid metal salts such as sodium adipate, sodium bis (4-
t-butylphenyl) phosphate, sodium-2,
Organic phosphate metal salts such as 2'-methylenebis (4,6-di-t-butylphenyl) phosphate and polyhydric alcohol derivatives such as dibenzylidene sorbitol and bis (methylbenzylidene) sorbitol have been used. Further, a method of adding an inorganic filler such as glass fiber or talc (magnesium silicate hydroxide) has also been performed.

[0003]

However, the effect of the addition of the above crystal nucleating agent is still insufficient, and addition of the inorganic filler causes problems such as increase in specific gravity and abrasion of the extrusion screw. The present invention is intended to eliminate the drawbacks of the prior art.

[0004]

SUMMARY OF THE INVENTION The present invention has a melt flow rate of 1 to 80 g / 10 minutes and an ethylene content of 2-1.
5% by weight of propylene-ethylene block copolymer 1
A polypropylene resin injection-molded article with improved heat resistance, which is obtained by injection-molding a composition comprising 00 parts by weight and 0.005 to 5 parts by weight of an aliphatic, alicyclic or aromatic dibasic acid diamide compound. It is related to.

The propylene-ethylene block copolymer used in the present invention has a melt flow rate of 1.
-80 g / 10 minutes, ethylene content 2-15 weight%. The propylene-ethylene block copolymer is a (co) polymer part (a) 98 consisting of a propylene homopolymer or a random copolymer of propylene and ethylene having an ethylene content of up to 3% by weight.
~ 20 wt% and ethylene content 30-80 wt%
As an example, a copolymer portion (b) composed of 2 to 80% by weight of a random copolymer of propylene and ethylene can be mentioned. In addition, the block copolymer has an intrinsic viscosity [η] at 23 ° C. of a para-xylene soluble component.
Those having a (measured in tetralin at 135 ° C.) of 1 to 6 dl / g are desirable.

The block copolymer is usually composed of, for example, a transition metal compound catalyst component such as titanium trichloride or titanium tetrachloride, or a catalyst component obtained by supporting them on a carrier whose main component is magnesium halide such as magnesium chloride. In the presence of a stereospecific polymerization catalyst formed by combining an organoaluminum compound such as triethylaluminum and diethylaluminum chloride, propylene is homopolymerized or a trace amount of ethylene and propylene are copolymerized to obtain the (co) polymer part (a). It is obtained by copolymerizing propylene and ethylene to produce a copolymer part (b) without deactivating the polymerization catalyst after the production of It is also possible to produce by mixing the (co) polymer part (a) and the copolymer part (b).

The propylene-ethylene block copolymer has an ethylene content of 2 to 15% by weight, preferably 3%.
When the content of ethylene is less than 2% by weight, the impact strength is insufficient, while the content of ethylene is 1% by weight.
When it exceeds 5% by weight, the rigidity becomes insufficient.

Melt flow rate of the propylene-ethylene block copolymer (measured according to JIS K7210 at a temperature of 230 ° C. and a load of 2.16 kg, hereinafter M
(FR) is 1 to 80 g / 10 minutes. The MF
When R is less than 1 g / 10 minutes, the moldability is poor, while when MFR exceeds 80 g / 10 minutes, the impact strength is insufficient.

The copolymerized portion of the propylene-ethylene block copolymer is preferably 2 to 80% by weight, particularly preferably 5 to 20% by weight, and the copolymerized portion is 2 to 20% by weight.
If it is less than wt%, the impact strength will be insufficient even if the rigidity is improved, while if it exceeds 80 wt%, the rigidity will tend to be insufficient even if the impact strength is improved. The content of ethylene in the copolymerized portion is preferably 20 to 80% by weight, and the content of ethylene is less than 20% by weight and 80% by weight.
If the weight is exceeded, the impact strength tends to be insufficient.

The aliphatic, alicyclic or aromatic dibasic acid type diamide compound used in the present invention is represented by the following chemical formula 1.
The compound of the general formula (1) represented by

[0011]

[Chemical 1] However, R ¹ in the general formula (1) represents a saturated or unsaturated aliphatic, alicyclic or aromatic dicarboxylic acid residue having ^{1 to} 28 carbon atoms, and R ² and R ³ are the same or different. , A C 3-18 cycloalkyl group, a cycloalkenyl group,
A group represented by the following formula (2) of the chemical formula 2 or a formula (3) of the chemical formula 2.
Represents a group represented by.

[0012]

[Chemical 2] However, R ⁴ and R ⁶ in the formula represent a hydrogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms, a cycloalkyl group or a phenyl group, and R ⁵ and R ⁷ represent a bond and a carbon number. 1 to
4 represents a linear or branched alkylene group.

The diamide compound represented by the general formula (1) can be obtained by amidating a predetermined aliphatic, alicyclic or aromatic dicarboxylic acid and a predetermined alicyclic or aromatic monoamine. .

Specific examples of the diamide compound represented by the general formula (1) include adipic acid dianilide, speric acid dianilide, N, N'-dicyclohexylterephthalamide,
N, N'-dicyclohexyl-1,4-cyclohexanedicarboxamide, N, N'-dicyclohexyl-
2,6-naphthalene dicarboxamide, N, N'-dicyclohexyl-4,4'-biphenyldicarboxamide, N, N'-bis (p-methylphenyl) hexanediamide, N, N'-bis (p- Examples thereof include ethylphenyl) hexanediamide and N, N'-bis (4-cyclohexylphenyl) hexanediamide.

The amount of the diamide compound added in the present invention is determined by the propylene-ethylene block copolymer (hereinafter referred to as
(It may be called a propylene-based resin) About 0.005-5 parts by weight, preferably 0.01-about 100 parts by weight
It is 1 part by weight, more preferably 0.02 to 0.5 part by weight. If it is less than 0.005 parts by weight, it is difficult to maintain or improve the impact resistance and at the same time it is difficult to significantly improve the heat distortion temperature, and even if it is added in an amount of more than 5 parts by weight, the impact resistance is not maintained. However, it is difficult to improve the heat distortion temperature at the same time, and it is also economically disadvantageous.

In the composition according to the present invention, the diamide compound may be added in advance during the polymerization of propylene, or may be added to and mixed with a polypropylene resin prepared separately. In the case where a polypropylene resin produced without passing through the detouching step is used in the composition according to the present invention, an appropriate amount of the neutralizing agent may be used in order to avoid the influence of the catalyst residue. The amount used is usually 0.01 to 5 with respect to 100 parts by weight of the polypropylene resin.
Parts by weight. Examples of the neutralizing agent include metal soaps, hydrotalcites, aluminum calcium silicate, metals of Group II of the periodic table and oxides and hydroxides of metals such as zinc, aluminum, tin and lead. You can As the neutralizing agent (which also serves as a dispersant), it is particularly preferable to use metal soap or hydrotalcite. Examples of the metal soap include metal salts of higher fatty acids or fatty acid oxyacids with metals such as magnesium, calcium, barium, zinc, aluminum, tin and lead. Examples of higher fatty acids include chain monocarboxylic acids having 10 to 22 carbon atoms, and stearic acid, lauric acid and the like are preferable. Examples of the fatty acid oxyacid include those having an alcoholic hydroxyl group in the side chain of an aliphatic carboxylic acid, and lactic acid, citric acid, hydroxystearic acid and the like are preferable. Preferred examples of the metal soap include magnesium stearate, calcium stearate, barium stearate, zinc stearate, aluminum stearate, calcium citrate, calcium lactate, calcium 12-hydroxystearate, calcium stearyl lactate, calcium lauryl lactate and the like. To be Hydrotalcites include magnesium, calcium,
It does not contain water-containing basic carbonates such as zinc, aluminum or bismuth, or water of crystallization, and includes natural products and synthetic products. As a natural product, Mg ₆ Al ₂ (OH) ₁₆ CO ₃ ·
An example is a 4H ₂ O structure. In addition, as a synthetic product, Mg _0.7 Al _o.3 (OH) ₂ (CO ₃ ) _0.15 · 0.5
4H ₂ O, Mg _4.5 Al ₂ (OH) ₁₃ CO ₃ · 3.5H
₂ O, Mg _4.2 Al ₂ (OH) _12.4 CO ₃ , Zn ₆ Al ₂ (O
_{H) 16 CO 3 · 4H 2} O, Ca 6 Al 2 (OH) 16 CO 3 ·
_{4H 2 O, Mg 14 Bi 2} (OH) 29.6 · 4.2H 2 O , and the like. Examples of oxides and hydroxides of metals of Group II of the periodic table include magnesium oxide, calcium oxide,
Zinc oxide, calcium hydroxide, aluminum hydroxide, magnesium hydroxide and the like are particularly preferable.

The composition according to the present invention may further contain other additives such as antioxidants, inorganic fillers, antistatic agents, pigments and dyes, if necessary, within the range that does not impair the effects of the present invention. May be added. Examples of the antioxidant include pentaerythritol-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], which is a phenolic antioxidant; and tris (), which is a phosphorus antioxidant. 2,4-di-t-butylphenyl) phosphite and the like can be mentioned. These antioxidants are usually used in 0.005 to 2 parts by weight with respect to 100 parts by weight of the propylene resin. Examples of inorganic fillers include talc, calcium carbonate, gypsum, carbon black, clay,
Examples include kaolin, silica, diatomaceous earth, and the like. Examples of antistatic agents include non-anionic surfactants and the like.

In the composition according to the present invention, a diamide compound, a neutralizing agent and other additives used as necessary are added to a propylene resin, and the mixture is dry blended with, for example, a super mixer, and then an extruder or the like. It can be obtained by granulating with, cooling, and pelletizing. The injection-molded article of the present invention is obtained by injection-molding the pellet. Injection molding is usually 180-3
It is carried out under heating at a temperature of 00 ° C. Examples of injection-molded products include interior materials that require heat resistance during injection molding and / or use of the molded products, automobile parts such as engine parts such as batteries, and household appliances. In molding an injection-molded article, in order to further develop its effect, molding under slow cooling from a molten state is preferable,
The cooling rate is preferably 5 ° C./sec or less on average.

[0019]

EXAMPLES The present invention will be described in detail below with reference to examples. In addition, the measuring method of the physical-property value in an Example is as follows. (1) Heat distortion temperature (° C); JIS-K7203, test temperature 25 ° C, test speed 10 mm / min (2) DuPont impact strength (kgf / cm); JIS-K
7203, t = 2 mm, measurement temperature 23 ° C and -20 ° C

Example 1 Propylene-ethylene block copolymer [MFR = 1
0 g / 10 min, ethylene content 7.5% (weight basis, the same below), proportion of copolymer part (hereinafter referred to as A value) 1
5%, ethylene content of the copolymer portion (hereinafter referred to as B value) 50%, and intrinsic viscosity [η] 3.5 dl / g of para-xylene-soluble component at 23 ° C. of 0.3% adipic acid dianilide.
2 parts by weight of a phenolic antioxidant pentaerythritol-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] (Ciba.
Product name Irganox 1010) manufactured by Geigy Corporation.
05 parts by weight of Tris (2,4-
0.05 parts by weight of di-t-butylphenyl) phosphite (trade name, Mark 2112, manufactured by Asahi Denka Co., Ltd.) and 0.10 parts by weight of calcium stearate are added and blended,
50 after dry blending using a super mixer
mmφ extrusion molding machine (L / D = 28) was used to make pellets, and the obtained pellets were made 210 mm by an injection molding machine.
℃, mold temperature 60 ℃, cooling time 40 seconds, average cooling rate 4
A test piece was obtained by molding under conditions of ° C / sec or less. The physical properties of the test piece were measured according to the test method described above. The results are shown in Table 1. The results are shown in Table 1.

Example 2 In Example 1, N, N was used instead of dianilide adipic acid.
A test piece was prepared in the same manner as in Example 1 except that ′ -dicyclohexyl-2,6-naphthalene dicarboxamide (hereinafter referred to as naphthalene dicarboxamide) was used, and the physical properties of the test piece were measured according to the test method. It was measured. The results are shown in Table 1.

Example 3 In Example 2, as a propylene-ethylene block copolymer, MFR was 30 g / 10 min, ethylene content was 5.0%, A value was 10%, B value was 50%, and intrinsic viscosity [η]. Was used in the same manner as in Example 2 except that the test piece was 2.5 dl / g.
The physical properties were measured according to the test methods described above. The results are shown in Table 1.

COMPARATIVE EXAMPLE 1 In Example 1, except that t-butylbenzoic acid aluminum salt (trade name AL-PTBBA manufactured by Dainippon Ink and Chemicals, Inc.) (hereinafter referred to as shell nucleating agent) was added and blended in place of dianilide adipic acid A test piece was prepared in the same manner as in Example 1, and the physical properties of the test piece were measured according to the above-mentioned test methods. The results are shown in Table 1.

Comparative Example 2 A test piece was prepared in the same manner as in Example 3 except that a shell nucleating agent was added instead of naphthalene dicarboxamide, and the physical properties of the test piece were measured according to the test methods described above. Was measured. The results are shown in Table 1.

Comparative Example 3 Sodium-2,2'-methylene bis (4,6-di-) was used in place of naphthalene dicarboxamide in Example 3.
t-butylphenyl) phosphate (Asahi Denka Kogyo KK,
A test piece was prepared in the same manner as in Example 3 except that the trade name NA-11) (hereinafter referred to as NA-11) was added and blended, and the physical properties of the test piece were measured according to the above-described test methods. The results are shown in Table 1.

[0026]

[Table 1]

As shown by the results in Table 1, the injection-molded article of the present invention has a high heat distortion temperature and the impact strength at room temperature and low temperature which is further required for the molded article made from the propylene-ethylene block copolymer. It can be seen that both are improved.

[0028]

INDUSTRIAL APPLICABILITY The injection-molded article of the present invention is an injection-molded composition obtained by mixing a specific propylene-ethylene block copolymer with a specific compounding agent. It also has high impact strength both at room temperature and low temperature, and is extremely useful as automobile parts and household appliances parts that require heat resistance during injection molding of propylene-ethylene block copolymer and / or when using the molded product. is there.

Claims (1)

[Claims] 1. A melt flow rate of 1 to 80 g / 10.
And 100 parts by weight of a propylene-ethylene block copolymer having an ethylene content of 2 to 15% by weight and an aliphatic, alicyclic or aromatic dibasic acid diamide compound 0.005
A polypropylene-based resin injection-molded article having improved heat resistance, which is obtained by injection-molding a composition comprising 5 to 5 parts by weight.