JPH057418B2 - - Google Patents

Description

[Detailed description of the invention]

[Field of Industrial Application] The present invention relates to a propylene-ethylene copolymer composition, and more specifically, it has excellent properties in impact resistance, rigidity, and resistance to whitening upon impact, and also has the above three properties. The present invention relates to a propylene-ethylene copolymer composition having a novel composition that also has an excellent balance of properties. [Prior Art and its Problems] Propylene-ethylene copolymers are polymers with high impact strength and rigidity, and are therefore prized in various industrial fields. However, this polymer, on the other hand, exhibits a phenomenon of impact whitening, in which stressed areas become white when an impact is applied or when the polymer is bent. Therefore, the appearance of the molded product is easily damaged, and its use is particularly limited in products where appearance is important, such as automobile parts and home appliances. In order to solve such problems, traditionally,
Method of mixing polyethylene with propylene-ethylene copolymer (JP-A-55-58245, JP-A-57-
137341, etc.), and a method of synthesizing the above copolymer by two-stage polymerization (Japanese Patent Publication No. 49-24593, Japanese Patent Application Laid-Open No. 1983-1989)
-61418, JP-A-56-55416, etc.) have been proposed. However, in the case of the former method, the improvement in impact whitening resistance is insufficient, and furthermore, it is difficult to achieve uniform mixing industrially. In the case of the latter method, there is a problem in that it is not possible to obtain a product that satisfies the balance of the three properties described above, that is, impact resistance, rigidity, and resistance to whitening. [Problems to be Solved by the Invention] The present invention solves the above-mentioned problems of propylene-ethylene copolymers, and produces propylene with a new composition that is excellent in all of the above three properties and is well-balanced. - To provide an ethylene copolymer composition. [Means for Solving the Problems] As a result of extensive research in order to achieve the above object, the present inventors have found that a predetermined amount of the fatty acid ester described below is blended into a specific propylene-ethylene copolymer produced by multi-stage polymerization. The present inventors have discovered that the composition can achieve the intended purpose, and have developed the composition of the present invention. That is, the propylene-ethylene copolymer composition of the present invention comprises a propylene-ethylene copolymer composition.
100 parts by weight; 0.02 to 2.0 ester of aliphatic saturated monocarboxylic acid having 14 to 22 carbon atoms and polyhydric alcohol
parts by weight; the propylene-ethylene copolymer is synthesized using a stereoregular catalyst and contains the following two components: (A): Propylene homopolymer or ethylene content: 2
% or less propylene-ethylene copolymer 70~95
Weight%, and (B): Propylene with ethylene content of 10 to 50% by weight.
It is characterized by being a copolymer consisting of 30 to 5% by weight of ethylene copolymer. One of the components of the present invention is a propylene-ethylene copolymer synthesized by a multi-stage polymerization method, for example, a two-stage polymerization method. The stereoregular catalyst used in the above polymerization method is
It is a catalyst generally used for stereoregular polymerization reactions of ethylene, propylene, etc., and usually consists of a transition metal halide component and an organoaluminum compound component. Here, as the transition metal halide compound, a titanium halide is preferable, and titanium trichloride is particularly preferable. Titanium trichloride is obtained by reducing titanium tetrachloride by various methods; these are further activated by ball milling and/or solvent washing (for example, washing with an inert solvent and/or an inert solvent containing a polar compound). Titanium trichloride or titanium trichloride eutectic (e.g. TiCl ₃ +1/3 AlCl ₃ ) is further co-pulverized with amines, ethers, esters, sulfur, halogen derivatives, organic or inorganic nitrogen compounds or phosphorus compounds, etc. Examples include those obtained by precipitation from liquefied titanium trichloride in the presence of an ether compound, and those obtained by the method described in Japanese Patent Publication No. 53-3356.
Furthermore, a material in which a titanium halide is supported on a magnesium compound can also be used. The organoaluminum compound of other components has the following formula: AlRnX ₃ -n where R is an alkyl group having 1 to 10 carbon atoms, an alkoxy group, or an aryl group, X is a halogen atom, and n is 0<n≦ Compounds having a value of 3) are preferred. Specifically, for example, triethylaluminum, triisobutylaluminum, tri-n-propylaluminum, diethylaluminium monochloride, diethylaluminum monobromide, diethylaluminium monoiodide, diethylaluminum monoethoxide, diisobutylaluminum monoisobutoxide , diethylaluminum monohydride, diisobutylaluminum monohydride, ethylaluminum sesquichloride, etc., and one or more of these can be used. These catalyst components are usually mixed in a ratio of 1 to 100 moles of the organoaluminum compound to 1 mole of the transition metal halide compound. Also,
It is also possible to improve the catalyst performance by using various electron-donating compounds as the third component. Such a stereoregular catalyst is used in each step of the polymerization reaction in a conventionally used amount and combination of components. Known methods can be used as the polymerization method, such as slurry polymerization, solution polymerization, gas phase polymerization, and liquid phase polymerization using propylene or ethylene monomers as a medium. When synthesizing by a two-stage polymerization method, in the first stage,
Propylene homopolymer or propylene-ethylene copolymer having an ethene content of 2% by weight or less in the polymer is controlled so as to produce 70 to 95% by weight of the total polymerization amount. It is preferably managed to produce 75 to 92% by weight. If a copolymer having an ethylene content of more than 2% by weight is used in the first stage, the stiffness of the resulting composition will be significantly reduced, which is unsuitable. In the second stage, ethylene is further polymerized to the copolymer obtained in the first stage polymerization reaction, and a propylene-ethylene copolymer having an ethylene content of 10 to 50% by weight is added to 5 to 5% of the total polymerization amount. It is controlled to produce 30% by weight, preferably 8 to 25% by weight. If a copolymer with an ethylene content of less than 10% by weight is used, the impact resistance of the resulting composition will decrease, and if it is more than 50% by weight, the effect of improving the whitening resistance of the composition will decrease. is insufficient. If the amount of the propylene-ethylene copolymer produced is less than 5% by weight of the total polymerized amount, the impact resistance of the composition will decrease, and if it is more than 30% by weight, the rigidity of the composition will decrease. . In terms of its structural characteristics, the propylene-ethylene copolymer obtained by the two-stage polymerization method has ¹³ C-
Triad fraction measured by NMR: [R]/f _EEE is preferably 2 or more. [R]/f _EEE is 2
This is because the above copolymer further improves the whitening resistance of the composition produced using the copolymer. Here, [R] is the sum of chains linking propylene and ethylene in the copolymer (f _PPE
+f _PEP +f _EEP +f _EPE (E represents ethylene and P represents propylene), and f _EEE represents a chain in which three ethylenes are bonded. In addition, the peak attribution during the measurement of the triad fraction is determined based on the method described in Macromolecules, Vol. 11, pp. 33, 1978. Another component of the composition of the present invention is an ester of an aliphatic saturated monocarboxylic acid having 12 to 22 carbon atoms and a polyhydric alcohol. The carboxylic acid may be any saturated monovalent carboxylic acid having 14 to 22 carbon atoms, but
Specific examples include myristic acid, palmitic acid, stearic acid, arachidic acid, and behenic acid. Examples of polyhydric alcohols include dihydric alcohols such as ethylene glycol, propylene glycol, ethyl ethylene glycol, trimethylene glycol, and tetramethylene glycol; trihydric alcohols such as propanetriol, methylpropanetriol, butanetriol, pentanetriol, and hexanetriol; Examples include tetrahydric alcohols such as erythritol, pentaerythritol, diglycerin, and sorbitan; pentahydric alcohols such as adonite and arabitto; and hexahydric alcohols such as aritritol, talitol, sorbitol, and mannitol. Particularly preferred are trihydric alcohols. Among these esters synthesized from an aliphatic saturated monocarboxylic acid and a polyhydric alcohol, those suitable for use in the present invention are those synthesized from an aliphatic saturated monocarboxylic acid having 14 to 20 carbon atoms and a polyhydric alcohol. It is a monoester of Specifically, stearic acid monoglyceride, palmitic acid monoglyceride, and myristic acid monoglyceride can be exemplified. Each of these may be used alone, or two or more types may be mixed as appropriate. Further, the ester may contain an unsaturated acid ester, other carboxylic acid, alcohol, etc., as long as it is 20% by weight or less. When producing the composition of the present invention, based on 100 parts by weight of the above propylene-ethylene copolymer,
Add 0.02 to 2 parts by weight of ester. If the amount of ester blended is less than 0.02 parts by weight, the effect of improving the whitening resistance of the composition will be poor, and if it exceeds 2% by weight, the bleeding phenomenon will occur frequently and the surface properties will deteriorate, especially for food products. There is no choice but to limit its use to relationships. Preferably 0.05 to 1.5 parts by weight,
More preferably, it is 0.1 to 1.0 parts by weight. The composition can be prepared by premixing the above two components using, for example, a Henschel mixer or a ribbon blender, and then melt-kneading the resulting pellets using an extruder, which is then injection molded, or by injection molding the pellets.
It can be produced by adding and mixing the above ester to an ethylene copolymer and then injection molding the mixture. At this time, predetermined amounts of commonly used antioxidants, antistatic agents, ultraviolet light inhibitors, neutralizing agents, pigments, and the like may be added and blended as necessary. [Examples of the invention] Examples 1 to 11 Types A to 1 shown in Table 1 were prepared by two-stage polymerization using a conventional method.
A propylene-ethylene copolymer of I was synthesized.
The ethylene content, polymerization amount, and [R]/f _EEE of the obtained copolymer in each stage are shown.

[Table] As esters, a: stearic acid monoglyceride (C ₁₈ ; trade name, Rikemar S-100, manufactured by Riken Vitamin Co., Ltd.), b: palmitic acid monoglyceride (C ₁₆ ; trade name, NAA-160, NOF) Co., Ltd.),
c: myristic acid glyceride (C ₁₄ ; trade name,
NAA-142, NOF Corporation), d: Lauric acid glyceride ( _C12 ; trade name, NAA-122, NOF Corporation)
Co., Ltd.) and e: oleic acid monoglyceride (C ₁₈ , unsaturated; trade name, Rikemar OL-100, manufactured by Riken Vitamin Co., Ltd.). Both were combined as shown in Table 2, premixed in a Henschel mixer, and then melted and kneaded in an extruder to form pellets, which were injection molded. The flexural modulus, Izot impact strength, and impact whitening area of each of the obtained molded products were measured according to the following specifications, and the results are summarized in Table 2. Flexural modulus: Conforms to JIS K-7203 Izot impact strength: JIS K-7110 (with notch,
(23℃) Impact whitening area: Square plate after injection molding (65mm x 65mm
x 3.2 mm) on the pedestal of a Dupont falling weight impact tester, and the tip of a 1/2 inch diameter striking rod was brought into contact with the center of the square plate.
Place a 1 kg weight on the striking rod at a height of 50 cm (temperature 23
The center of the square plate was caused to whiten by dropping it from a temperature of ^100.degree . The smaller this value is, the better the whitening resistance is.

【table】

[Table] [Effects of the Invention] As is clear from the above explanation, the composition of the present invention has excellent impact resistance, rigidity, and impact whitening resistance, and at the same time has a good balance of the three properties. It is useful as a sheet molding material and blow molding material in the fields of automobiles and home appliances where appearance is important, and its industrial value is great.

Claims (1)

[Claims] 1 100 parts by weight of propylene-ethylene copolymer;
0.02 to 2.0% by weight of an ester of an aliphatic saturated monocarboxylic acid having 14 to 22 carbon atoms and a polyhydric alcohol; The following two components were synthesized: (A): Propylene homopolymer or ethylene content 2
Propylene-ethylene copolymer up to 70% by weight
~95% by weight, and (B): propylene with an ethylene content of 10 to 50% by weight.
A propylene-ethylene copolymer composition characterized in that it is a copolymer comprising 30 to 5% by weight of an ethylene copolymer.