JP2003034742A - Method of preventing flow mark deterioration of polypropylene resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of preventing a flow mark deterioration of a polypropylene-based resin composition which is used for an automobile exterior member or an outdoor structure member while maintaining good moldability and mechanical properties. SOLUTION: In this method, polypropylene is blended with a rubber component blended with a weathering stabilizer in advance or polypropylene is blended with a rubber component and carbon black without blending the weathering stabilizer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is intended to prevent a phenomenon in which the appearance of flow marks is deteriorated with the passage of time in a polypropylene resin composition used for automobile exterior members and outdoor use members exposed to direct sunlight. Regarding the method.

[0002]

2. Description of the Related Art Conventionally, as a vehicle interior / exterior member, there have been proposed a number of composite materials of polypropylene resin compositions containing polypropylene as a base, to which rubber, an inorganic filler and the like are added. Moldability, mechanical characteristics, appearance characteristics, etc. are required for these automobile polypropylene composite material parts,
In particular, appearance characteristics are important factors that affect the commercial value of the product. In the case of a large-sized molded product such as a bumper, the longer the flow length, the more unstable the flow of the resin, resulting in a defective appearance such as a flow mark pattern on the component immediately after the molding.

The flow mark pattern observed immediately after molding has become almost inconspicuous due to improvements in resin and molding conditions and has reached a level at which there is no problem. (This phenomenon is called "flow mark deterioration") may occur.
(Figure 1). This flow mark deterioration is rarely a problem because many bumpers are currently painted, but with partially painted or unpainted bumpers, the quality deteriorates.
It can be a complaint. Incidentally, in order to improve the weather resistance of the propylene polymer composition containing rubber, there is known a method of adding a weather resistance agent to a rubber component to be added later and blending it with a crystalline propylene polymer (Japanese Patent Publication No. 7-119331). Gazette). However, there is no suggestion or disclosure regarding improvement of flow mark deterioration prevention.

[0004]

In view of the above circumstances, the object of the present invention is to maintain good moldability and mechanical properties in polypropylene resin compositions used for automobile exterior members and outdoor use members. However, it is another object of the present invention to provide a method for preventing flow mark deterioration.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies as to a method for preventing flow mark deterioration of a polypropylene resin composition having the above-mentioned problems. It was found that the flow mark deterioration occurs due to the rapid photo-deterioration of the added rubber component. Further, based on this finding, the compounding method of the weather resistance agent or carbon black is changed so that the rubber component is preliminarily mixed and kneaded (called blend) with polypropylene, or the weather resistance agent is blended. It has been confirmed that flow mark deterioration can be prevented by blending a rubber component and carbon black in polypropylene without blending, and the present invention has been accomplished.

That is, the present invention provides the following method for preventing flow mark deterioration of a polypropylene resin composition. [1] A method for preventing flow mark deterioration of a polypropylene-based resin composition, which comprises preliminarily blending a weathering agent with a rubber component and then blending polypropylene. [2] Polypropylene contains the rubber component (A), and the total amount of the polypropylene (B) containing the rubber component (A) and the rubber component (D) added later is 100 parts by weight, and the rubber component (A) and the rubber. A method for preventing flow mark deterioration of a polypropylene resin composition according to 1, wherein the total amount of the component (D) is 10 to 50 parts by weight and the weather resistance agent (C) is 0.01 to 10 parts by weight. [3] A method for preventing deterioration of flow mark of 1 or 2 polypropylene resin composition in which carbon black is not blended. [4] A method for preventing flow mark deterioration of a polypropylene resin composition, which comprises blending polypropylene with a rubber component and carbon black without blending a weathering agent. [5] A method for preventing flow mark deterioration of a polypropylene resin composition according to 4, wherein carbon black is previously blended with the rubber component, and then polypropylene is blended.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below.
The method for preventing flow mark deterioration of the polypropylene resin composition of the present invention comprises a first method of blending a rubber component of [1] with a weathering agent in advance and then blending polypropylene.
There is a second method of blending polypropylene with a rubber component and carbon black without blending the weathering agent of [4].
In the following description, what is not distinguished between the first method and the second method is common to both methods.

The polypropylene used as a raw material in the present invention preferably contains a rubber component, and is usually composed of a propylene homopolymer and a propylene-α-olefin copolymer. This copolymer is the rubber component (A) and includes, for example, ethylene, 1-butene, 4-methylpentene-1,1-pentene, 1-
It is a polypropylene random copolymer composed of a copolymer of hexene and the like and propylene. If necessary, unsaturated carboxylic acid or its derivative, aromatic unsaturated monomer, vinyl ester, vinyl silane, etc. may be copolymerized at 5 mol% or less. Melt flow rate of the polypropylene (B) (MFR: JIS-K7210, 230 ° C., 2.
16 kg load) is 0.1 to 200 g / 10 minutes, especially 1
~ 150 g / 10 min is preferred. The polypropylene is produced by a known production method such as a Ziegler-Natta catalyst, a MgCl ₂ -supported catalyst, a metacelone catalyst, and a post-metaceron catalyst. As the polymerization method, in addition to being produced in a slurry state in a solvent such as heptane, it is produced by polymerizing in a liquid phase state or a gas phase state without a solvent. Furthermore, due to recent advances in catalyst technology, polymer production processes that do not require a decatalysis step have been realized, but the present invention is also applicable to polypropylene produced by these processes.

As the raw material polypropylene for the polypropylene resin composition of the present invention, a propylene-ethylene block copolymer containing a rubber component (A) such as a propylene-ethylene random copolymer is preferably used.
That is, since a rubber component such as a propylene-ethylene random copolymer is rapidly deteriorated by light, it easily causes a phenomenon of deterioration of appearance such as a flow mark, but the method of the present invention can prevent the deterioration of the flow mark. A method for producing a propylene-ethylene block copolymer is described in JP-A-1
Known methods described in, for example, JP-A 1-269218 can be used. For example, a method of blending the respective components obtained by separately polymerizing, or (a) (i) a solid catalyst component containing magnesium, titanium, a halogen atom and an electron donor, and optionally used ( ii)
A solid component composed of crystalline polyolefin,
Polymerization pressure 1 to 150 kg / cm ² G, polymerization temperature 30 to 100 in the presence of a catalyst system comprising (b) an organoaluminum compound and (c) an electron-donating compound that is usually used.
There is a method of carrying out multistage polymerization at ℃.

Examples of the post-addition rubber component (D) used in the present invention include ethylene-α-olefin copolymerization weights such as ethylene-propylene rubber, ethylene-1-butene rubber, ethylene-1-octene rubber. Examples thereof include compound rubber, isoprene rubber, butyl rubber, nitrile rubber, styrene-butadiene rubber and hydrogenated products thereof, and styrene-isoprene rubber and hydrogenated products thereof. Among them, preferable are ethylene-propylene rubber, ethylene-1 butene rubber, and ethylene-1-octene rubber, and most preferable are ethylene-1 butene rubber and ethylene-1 synthesized by metallocene catalyst. -Octene rubber. Especially, those having an ethylene content of 30 to 80% by weight are preferable.

The total amount of the rubber component (A) and the rubber component (D) is 100 parts by weight of the total amount of the polypropylene component (B) containing the rubber component (A) and the rubber component (D). It is 10 to 50 parts by weight, preferably 15 to 40 parts by weight. When the total amount of the rubber component (A) and the rubber component (D) is less than 10 parts by weight, the impact resistance is insufficient for use in, for example, automobile parts. Also,
When the rubber component is small as described above, flow mark deterioration is not a serious problem in many cases. When the total amount of the rubber component (A) and the rubber component (D) exceeds 50 parts by weight, heat resistance and rigidity are lowered, and the application is often limited. The ratio (A / D) of the rubber component (A) contained in the polypropylene (B) and the rubber component (D) added later is 1
/ 2 to 1/10 is preferable.

The weathering agent (C) used in the first method is a benzophenone type, a benzotriazole type, an amidine type,
It is a benzoate-based, salicylic acid ester-based, cyanoacrylic-based ultraviolet absorber, and a hindered amine-based, nickel complex salt-based, hindered amine-nickel complex salt-based light stabilizer. Of these, preferred are hindered amine light stabilizers and benzophenone and benzotriazole ultraviolet absorbers. Particularly preferred are benzotriazole-based UV absorbers and hindered amine-based light stabilizers having a molecular weight of 500 or more. The amount of the weather-resistant agent (C) used is 0.01 to 10 parts by weight, preferably 0.0 to 10 parts by weight, based on 100 parts by weight of the total of the polypropylene (B) containing the rubber component (A) and the rubber component (D).
2 to 5 parts by weight. If the amount of the weather resistance agent (C) used exceeds 10 parts by weight, bleeding may occur, and if it is less than 0.01 parts by weight, the effect of preventing flow mark deterioration deteriorates and weather resistance deteriorates.

The polypropylene resin composition used in the first method is also suitable for black coloring containing carbon black.
The weather resistance and the flow mark deterioration prevention property are improved as compared with those of the prior art. However, from the practical viewpoint, when carbon black is present, sufficient weather resistance and flow mark deterioration preventing property are often maintained during the period of use in ordinary applications, and the present invention is carried out by adding one step. Often do not feel the need. Therefore, the first method is particularly useful for making molded articles that do not contain carbon black rubber.

Further, the polypropylene resin composition based on the first method, even if it is a molded product containing no carbon black rubber, has a black panel temperature of 83 ° C. when measured using a sunshine weather meta. 500
It is possible to obtain a molded product in which the appearance of the flow mark does not deteriorate even after irradiation for a longer time. Therefore, the polypropylene-based resin composition based on the method of the present invention has sufficient weather resistance and flow mark deterioration during the required service life, even for automobile members that require long-term weather resistance and members for outdoor use that receive direct sunlight. Preventability can be retained.

As described above, in the first method, it is important to preliminarily contain a weathering agent in a dispersed state in the rubber component added later. As a method for producing the rubber masterbatch containing a weatherproofing agent, a pelletized or lumpy rubber component is kneaded with a weathering agent, impregnated with a weathering agent solution, or the rubber component is dissolved in a solvent together with the weathering agent. There are methods such as mixing and drying, and a single-screw extruder, a twin-screw extruder, a Henschel mixer, a Banbury, etc. are used according to known techniques. As a method of kneading a rubber masterbatch in which a weather resistance agent is preliminarily blended with polypropylene, a method according to a known technique is also used.

As described above, according to the first method of the flow mark deterioration preventing method of the present invention, the weather resistance is enhanced by using the master batch in which the weather resistant agent is preliminarily added to the rubber component to be added later, so that the flow mark deterioration is prevented. It suppresses. As a second method of the present invention, the polypropylene resin composition can be prevented from flow mark deterioration by blending a rubber component and carbon black in polypropylene without blending a weathering agent. In the second method, it is preferable to pre-blend carbon black with the rubber component and then blend polypropylene. The amount of the rubber component added at this time is the same as in the first method. The amount of carbon black added is 0.01 to 10 parts by weight, preferably 0.02 to 5 parts by weight, based on 100 parts by weight of the total of polypropylene and rubber components. However, the second method is advantageous because it does not use a weathering agent, but it can be applied only to black colored molded articles.

In the polypropylene resin composition of the present invention, in addition to these essential components, optional components can be added at any stage within a range that does not significantly impair the effects of the invention. As the optional components, for example, commonly used antioxidants, nucleating agents, heavy metal deactivators, lubricants, antistatic agents, dispersants or neutralizing agents such as metallic soaps and waxes, acid adsorbents, flow agents Sex modifier (peroxide), filler (talc, glass fiber, mica, barium sulfate, magnesium hydroxide, wood powder, nylon fiber, polyester fiber, inorganic / organic system such as cellulose), colorant (dye,
In addition to the (pigment) and the like, it is also possible to add other thermoplastic polymers for the purpose of improving physical properties such as rigidity, flexibility, adhesiveness and gloss. In particular, it is well known that the antioxidant affects not only the heat stabilization of the propylene polymer but also the weather resistance.

[0018]

EXAMPLES Next, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. The weather resistance test method used in Examples and Comparative Examples is as follows. (1) Preparation of test piece Using an injection molding machine, a polypropylene-based resin composition as a sample was used to form a flat plate (420 mm x 100 m) having a thickness of 3 mm.
m) was molded. (2) Flow mark deterioration time Using a sunshine weather meter (manufactured by Suga Test Instruments Co., Ltd.), a weather resistance test was conducted at a black panel temperature of 83 ° C., and the occurrence of flow mark deterioration was visually evaluated to determine the time until the flow mark was generated. It was defined as "flow mark deterioration time" (see Fig. 2).

Example 1 First, MFR (melt flow rate) at 230 ° C.
Is 35 g / 10 min and 70 parts by weight of polypropylene (PPI, J3083H manufactured by Idemitsu Petrochemical Co., Ltd.) made of a propylene-ethylene block copolymer containing 7% of an amorphous ethylene-propylene copolymer part (rubber component) is added as a weathering agent. ADEKA STAB LA57 (hindered amine light stabilizer, manufactured by Asahi Denka Kogyo) 0.025 parts by weight and Chemisorb 113 (benzoate ultraviolet absorber, manufactured by ChemiPro Kasei) 0.025
0.035 parts by weight of a 1: 1 mixture of Irganox 1010 (phenolic antioxidant, Ciba Specialty Chemicals) and Irgafos 168 (phosphorus antioxidant, Ciba Specialty Chemicals) as additives. Part by weight and 0.050 part by weight of calcium stearate (lubricant, manufactured by NOF CORPORATION) were blended, blended with a Henschel mixer, and then primary kneaded with a twin-screw extruder to obtain a polypropylene masterbatch. Also, 190 ℃
30 parts by weight of ethylene-butene rubber (Rubber 1) having an MFR of 1.2 g / 10 min. Was mixed with 0.15 parts by weight of a 1: 1 mixture of Irganox 1010 and Irgafos 168 as an additive and mixed with a Henschel mixer. Then, primary kneading was performed with a twin-screw extruder to obtain rubber pellets. Next, the obtained polypropylene masterbatch and rubber pellets were secondarily kneaded with a twin-screw extruder to produce a polypropylene resin composition.

Example 2 In Example 1, the polypropylene masterbatch was blended with the weathering agent in an amount of 0.050 parts by weight of ADEKA STAB LA57 (hindered amine light stabilizer) and Chemisorb 113.
(Benzoate UV absorber) A polypropylene resin composition was produced in the same manner as in Example 1 except that the amount was 0.050 part by weight.

Example 3 In Example 1, the weathering agent of the rubber masterbatch was ADEKA STAB LA57 (hindered amine light stabilizer) 0.0
25 parts by weight and Tinuvin 1577 (triazine ring type UV absorber, manufactured by Ciba Specialty Chemicals)
A polypropylene resin composition was produced in the same manner as in Example 1 except that the amount was 0.025 part by weight.

Example 4 In the polypropylene pellets of Example 1, 60 parts by weight of polypropylene (PP1) was added, and talc was further added in the secondary kneading of the polypropylene pellets and the rubber masterbatch.
A polypropylene resin composition was produced in the same manner as in Example 1 except that 0 part by weight was blended.

Example 5 A polypropylene resin was prepared in the same manner as in Example 4, except that the rubber masterbatch in Example 4 was mixed with 0.6 parts by weight of carbon black (furnace black, manufactured by Mitsubishi Chemical Co., Ltd.) without using a weathering agent. A composition was produced.

Comparative Example 1 In the secondary kneading of polypropylene pellets and a rubber masterbatch, 0.025 parts by weight of ADEKA STAB LA57 as a weathering agent and 0.025 parts of Chemisorb 113 were used in the secondary kneading without mixing the weathering agent in the rubber masterbatch of Example 1. A polypropylene resin composition was produced in the same manner as in Example 1 except that parts by weight were compounded.

Comparative Example 2 In the secondary kneading of polypropylene pellets and a rubber masterbatch, 0.025 parts by weight of ADEKA STAB LA57 as a weathering agent and 0.025 parts of TINUVIN 1577 were added to the rubber masterbatch of Example 1 without blending the weathering agent. A polypropylene resin composition was produced in the same manner as in Example 1 except that parts by weight were compounded.

Comparative Example 3 The polypropylene pellets of Comparative Example 1 were made to have 60 parts by weight of polypropylene (PP1), and talc was further added in the secondary kneading of the polypropylene pellets and the rubber masterbatch.
A polypropylene resin composition was produced in the same manner as in Comparative Example 1 except that 0 part by weight was blended.

Comparative Example 4 Same as Example 1 except that the rubber masterbatch of Example 1 was not blended with a weathering agent, and the secondary kneading of the polypropylene pellets and the rubber masterbatch was not blended with a weathering agent. A polypropylene resin composition was produced.

The polypropylene pellets of the polypropylene resin composition in each of the examples and comparative examples, the rubber masterbatch, the compounding amount (parts by weight) of each additive in the secondary kneading, and the flow mark deterioration time by the weather resistance test were measured. The results are shown in Table 1.

[0029]

[Table 1]

[0030]

EFFECT OF THE INVENTION The polypropylene-based resin composition according to the method of the present invention maintains the excellent moldability and mechanical properties of polypropylene, and suppresses the appearance deterioration phenomenon such as flow mark due to direct sunlight. It has excellent appearance characteristics and can be extremely advantageously used for automobile members that require long-term weather resistance and members for outdoor use that receive direct sunlight.

[Brief description of drawings]

FIG. 1 is a photograph showing a situation where a flow mark pattern is generated on a bumper.

FIG. 2 is a photograph showing the state of flow mark deterioration in a test piece, the upper figure being a test piece at the start of the test, and the lower figure being a photograph showing the state when a flow mark occurs.

Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08L 53/00 C08L 53/00 (72) Inventor Koji Tsujida 1 Anesaki Kaigan, Ichihara-shi, Chiba 1 (72) Inventor Higashi Yasushi, Ichihara-shi, Chiba 1F 1F, Anezaki coast (reference) 4J002 AC06Y AC07Y AC08Y BB05Y BB12W BB14X BB15X BB15Y BB18Y BP02W DA037 EE036 EH126 ET006 EU176 FD056 FD086 FD097 GL00 GN00

Claims (5)

[Claims] 1. A method for preventing flow mark deterioration of a polypropylene resin composition, comprising preliminarily blending a weathering agent with a rubber component and then blending polypropylene. 2. The rubber component (A), wherein the polypropylene contains the rubber component (A), and the total amount of the polypropylene (B) containing the rubber component (A) and the rubber component (D) added later is 100 parts by weight. And the total amount of rubber component (D) is 1
0 to 50 parts by weight, and 0.01 to 10 of the weather resistance agent (C).
The method for preventing flow mark deterioration of the polypropylene resin composition according to claim 1, which is parts by weight. 3. A method for preventing flow mark deterioration of a polypropylene resin composition according to claim 1, wherein carbon black is not blended. 4. A method for preventing flow mark deterioration of a polypropylene-based resin composition, which comprises blending polypropylene with a rubber component and carbon black without blending a weathering agent. 5. The method for preventing flow mark deterioration of a polypropylene-based resin composition according to claim 4, wherein carbon black is previously blended with the rubber component and then polypropylene is blended.