JP4088373B2 - Resin composition for molding automobile side molding and automobile side molding - Google Patents

Description

【００２０】
なお、（１）式中のコポリマー成分の分率（Ｗ_ＲＣ/100）は従来より知られている赤外線分析法などで求めることができる。
【００２１】
上記プロピレン系ブロック共重合体（Ａ）は、いかなる方法によって製造してもよく、例えば、ホモポリマーに本発明で規定した極限粘度を有するＥＰＲを添加したブレンド物として得てもよい。また、チタン含有固体触媒成分を用いて重合したエチレン−プロピレンランダム共重合体をホモポリマーに添加し、ブレンド物として製造してもよい。
但し、経済性の観点からは、ホモポリマー成分を重合し、続いてコポリマー成分を連続的に製造する方法によって得るのが最も好ましい。
【００２２】
本発明の自動車サイドモール成形用樹脂組成物は、一軸又は二軸押出機、バンバリーミキサー、ニーダー又はロールなどの従来より知られている混練機を用い、上記各種成分（Ａ）〜（Ｄ）及び必要な場合の各種添加剤を溶融・混練することにより製造することができる。
【００２３】
また、本発明の自動車サイドモールは、上述した本発明の自動車サイドモール用樹脂組成物に射出成形などの各種成型法を適用することにより得られるものである。
具体的には、図７に示すように、フェンダーサイドモール９、フロントサイドモール１０及びリアサイドモール１１として使用される。
【００２４】
【実施例】
以下、本発明を実施例及び比較例により更に詳細に説明するが、これらは本発明を具体的に説明するためのものであり、本発明は、これら実施例に限定されるものではない。
なお、以下の実施例及び比較例において、得られた成形品の評価方法としては、以下に記すものを採用した。
【００２５】
＜評価方法＞
基礎物性
◆メルトフローレート（ＭＦＲ）
ＪＩＳ Ｋ６７５８に規定された方法に従い、測定温度２３０℃、荷重２１．１８Ｎにて実施した。（単位：ｇ／１０ｍｉｎ）
【００２６】
◆曲げ弾性率
ＪＩＳ Ｋ７２０３に規定された方法に従い、測定温度２３℃、スパン長さ６０ｍｍ、荷重速度１．５ｍｍ／ｍｉｎにて実施した（単位：ＭＰａ）。
ＪＩＳ Ｋ６７５８に規定された方法に準拠して実施した。
【００２７】
◆線膨張係数（寸法安定性）
ＪＩＳ Ｋ７１９７に規定された方法に従い、昇温速度５℃／ｍｉｎ、荷重２ｇ、測定範囲−３０℃〜８０℃にて実施した（単位：×１０^−５ｃｍ／ｃｍ・℃）。
本評価では、線膨張係数が小さいほど、寸法安定性が優れていると言える。
【００２８】
◆静摩擦係数
ＡＳＴＭ Ｄ１８９４に規定された方法に準拠して実施した（単位：無次元）。
【００２９】
◆ブリード試験
１００ｍｍ×１００ｍｍ×２ｍｍの平板状試験片を湿度５０％、室温２３℃の室内で７２０時間状態調節し、目視にて試験片表面にブリード物の発生があったものを「×」、発生のなかったものを「○」とした。
【００３０】
製品試験
◆サイドモールの射出成形及び離型性の評価
自動車サイドモールは、図１及び図２に示した金型において、型締め力８５０ｔの射出成形機を用い、ホットランナー部６を経由し、端末より１箇所のフィルムゲート４から金型キャビティ部３に樹脂を注入し、射出成形して得た。
その際、サイドモール成形品（図３及び図４参照）がキャビティ金型１又はコア金型２から容易に取り出せた場合には、離型性を「○」、取り出せない場合には、離型性を「×」とした。
なお、成形時の各種条件としては、
射出圧：８００ｋｇ／ｃｍ^２
射出速度：４０ｍｍ／秒
シリンダー設定温度：２１０℃
ホットランナー部設定温度：２２０℃
を採用した。
【００３１】
◆外観（フローマーク）試験
射出成形により得られたサイドモール成形品の外観を目視評価し、フローマーク８の発生の有無を確認し、フローマークの発生のないもの（図５参照）を「○」、発生が確認されたもの（図６参照）を「×」とした。
【００３２】
◆サイドモールの自動車車体への貼付試験
アクリル系両面テープ（住友３Ｍ製）を介して、射出成形により得られたサイドモール成形品のリブ部７と鋼鉄製の板を貼り付ける。
次に、サイドモールの上面部に６０℃に加熱したケロシンを１分間噴霧した後、予め−３０℃に保持された恒温槽にて２時間冷却処理し、更に予め８０℃に保持された恒温槽にて２時間加熱処理し、この冷却処理と加熱処理とをそれぞれ１０回繰り返し処理して、サイドモール成形品が鋼鉄製の板から剥離しないものを「○」、剥離したものを「×」とした。
【００３３】
下記の実施例及び比較例で使用した配合成分の材質や特性を以下に示す（表１参照）。
＜配合成分＞
●ＰＰ−１
［η］_ＲＣ １．９ｄｌ／ｇ
［η］_ＰＰ １．９ｄｌ／ｇ
Ｗ_ＰＰ/Ｗ_ＲＣ ２．０
であるプロピレン系ブロック共重合体。
【００３４】
●ＰＰ−２
［η］_ＲＣ ３．０ｄｌ／ｇ
［η］_ＰＰ ３．０ｄｌ／ｇ
Ｗ_ＰＰ/Ｗ_ＲＣ ２．０
であるプロピレン系ブロック共重合体。
【００３５】
●ＰＰ−３
［η］_ＲＣ ２．０ｄｌ／ｇ
［η］_ＰＰ ２．０ｄｌ／ｇ
Ｗ_ＰＰ/Ｗ_ＲＣ １．５
であるプロピレン系ブロック共重合体。
【００３６】
●ＰＰ−４
［η］_ＲＣ １．５ｄｌ／ｇ
［η］_ＰＰ １．５ｄｌ／ｇ
Ｗ_ＰＰ/Ｗ_ＲＣ ２．１
であるプロピレン系ブロック共重合体。
【００３７】
●ＰＰ−５
［η］_ＲＣ ２．１ｄｌ／ｇ
［η］_ＰＰ ２．１ｄｌ／ｇ
Ｗ_ＰＰ/Ｗ_ＲＣ ３．０
であるプロピレン系ブロック共重合体。
【００３８】
●分子量降下剤
１，３−ビス（ｔ−ブチル−パーオキシイソプロピル）ベンゼン
【００３９】
●エチレン系エラストマー−１
オクテン含有量が２０重量％、ＭＦＲが２７ｇ／１０ｍｉｎ（２３０℃；２１．１８Ｎ）であるエチレン・オクテン共重合体ゴム
●エチレン系エラストマー−２
オクテン含有量２４重量％、ＭＦＲが２ｇ／１０ｍｉｎ（２３０℃；２１．１８Ｎ）であるエチレン・オクテン共重合体ゴム
【００４０】
●タルク−１
平均粒径が２．０μｍであるタルク
●タルク−２
平均粒径が４．８μｍであるタルク
【００４１】
（実施例１、比較例１〜９）
後述の表１に示す配合（配合比：重量％）を採用し、ＰＰ−１〜５、分子量降下剤、エチレン系エラストマー、タルクを配合し、組成物を得た。更に該組成物１００重量部、フェノール系酸化防止剤０．１重量部、ステアリン酸カルシウム０．１重量部を、高速撹拌式混合機（ヘンセルミキサー、商品名）で室温下にて３分間混合し、組成物を得、該組成物をスクリュー口径５０ｍｍ、シリンダー設定温度２００℃の押出造粒機（ナカタニ機械製ＮＶＣ−５０）を用いて造粒し、ペレット状の組成物を得た。
該組成物を、型締め力１００ｔの射出成型機（東芝機械製 ＩＳ−１００）を用い、シリンダー温度２３０℃、射出速度３０ｍｍ／秒、金型通水温度５０℃条件下で試験片を作成し、該試験片を湿度５０％、室温２３℃の室内で７２時間状態調節した。次いで、ＭＦＲ、曲げ弾性率、線膨張係数、静摩擦係数、ブリード試験の評価を行い、更に製品試験を実施した。評価結果を表１に示した。
【００４２】
【表１】

【００４３】
表１により明かなように、本発明の範囲に属する実施例１は、ベタツキ、ブリードが少なく、柔軟性、寸法安定性及び外観の全てに優れていることが分かる。
【００４４】
【発明の効果】
以上説明してきたように、本発明によれば、プロピレンのホモポリマー成分とエチレン−プロピレン共重合体成分の重合生成比とそれぞれの成分の極限粘度を制御し、特定のエチレン系エラストマー、タルク及び分子量降下剤を適切に選択して使用することとしたため、柔軟性、寸法安定性、外観及び経済性に優れ、しかもベタツキの少ない自動車サイドモール成形用の樹脂組成物及びこれを用いた自動車サイドモールを提供することができる。
即ち、本発明の自動車サイドモール成形用樹脂組成物は、かかる優れた特性を有するため、これを成形原料として得られる自動車サイドモールは、図７に示したような自動車サイドモールとして使用するのに好適である。
【００４５】
【図面の簡単な説明】
【図１】自動車サイドモールの射出成形に用いた金型を示す断面図である。
【図２】自動車サイドモールの射出成形に用いたキャビティ金型の斜視図である。
【図３】自動車サイドモールの底面図である。
【図４】自動車サイドモールの断面図である。
【図５】自動車サイドモールの上面図である。
【図６】自動車サイドモールのフローマーク部を示す上面図である。
【図７】自動車サイドモールを使用した自動車を示す側面図である。
【符号の説明】
１・・・・・・・・キャビティ金型部
２・・・・・・・・コア金型部
３・・・・・・・・キャビティ部
４・・・・・・・・ゲート部
５・・・・・・・・ランナー部
６・・・・・・・・ホットランナー部
７・・・・・・・・リブ部
８・・・・・・・・フローマーク部
９・・・・・・・・フェンダーサイドモール
１０・・・・・・・フロントドアサイドモール
１１・・・・・・・リアドアサイドモール[0001]
[Technical field to which the invention belongs]
The present invention relates to a resin composition for molding an automobile side molding which is excellent in flexibility, dimensional stability, appearance and economy, and has less stickiness, and an automobile side molding obtained by injection molding the composition.
[0002]
[Prior art]
Molded articles using polypropylene (propylene homopolymer, ethylene-propylene random copolymer, and ethylene-propylene block copolymer) are relatively economical and recyclable. in use. However, polypropylene has the disadvantages of high rigidity and poor dimensional stability, so it is not suitable for automobile side molding materials.
[0003]
[Problems to be solved by the invention]
On the other hand, the polypropylene is usually softened by adding an amorphous or low crystalline elastomer to the polypropylene. However, this method has a room for improvement such as an increase in linear expansion coefficient and dimensional stability.
In order to improve the softening and dimensional stability of polypropylene, a method of simultaneously blending an amorphous or low crystalline elastomer and talc into polypropylene has been performed. However, in this method, it is necessary to add a large amount of elastomer, there is room for improvement in terms of economy, and a flow mark is generated in the obtained molded product, which may adversely affect the appearance of the molded product. there were.
[0004]
Japanese Patent Application Laid-Open No. 7-258182 proposes increasing the stereoregularity of polypropylene as a method for improving the appearance of a molded product. However, in this method, the rigidity of the polypropylene becomes high, and it is necessary to add a large amount of elastomer, and there is room for improvement in terms of fluidity and dimensional stability.
Furthermore, as a method for improving the flexibility, dimensional stability and appearance of the molded product, as disclosed in JP-A-9-194553, the homopolymer component in the propylene-based block copolymer and ethylene-propylene can be used. Control of the intrinsic viscosity of the copolymer component has been proposed. However, this method has room for improvement in terms of the stickiness of the molded product and the balance of fluidity.
[0005]
The present invention has been made in view of such problems of the prior art, and the object of the present invention is to form an automobile side molding that is excellent in flexibility, dimensional stability, appearance and economy, and has less stickiness. The object is to provide a resin composition for automobiles and an automobile side molding using the same.
[0006]
[Means for Solving the Problems]
As a result of intensive studies aimed at solving the above-mentioned problems, the present inventors have controlled the polymerization formation ratio of the homopolymer component of propylene and the ethylene-propylene copolymer component and the intrinsic viscosity of each component, By appropriately selecting and using specific ethylene-based elastomers, talc and molecular weight depressants, an automotive side molding molding resin composition having excellent flexibility, dimensional stability, appearance and paintability and less stickiness is obtained. As a result, the present invention has been completed.
[0007]
That is, the resin composition for molding an automobile side molding of the present invention comprises (A) 77.92 to 81.94% by weight of a propylene-based block copolymer, (B) 9 to 11% by weight of an ethylene-based elastomer, and (C A resin composition for molding an automobile side molding comprising 9 to 11% by weight of talc having an average particle size of 3.0 μm or less and (D) 0.06 to 0.08% by weight of a molecular weight depressant. ,
The propylene-based block copolymer (A) includes a homopolymer component of propylene and a copolymer component of ethylene-propylene,
Both the intrinsic viscosity [η] _{PP of the} homopolymer component and the intrinsic viscosity [η] _{RC of the} copolymer component are 1.8 to 2.0 dl / g,
The weight ratio (W _PP / W _RC ) between the weight W _PP of the homopolymer component and the weight W _{RC of the} copolymer component is 1.9 to 2.1.
[0008]
Moreover, the automobile side molding of the present invention is obtained by using the molding resin composition described above.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the resin composition for molding an automobile side molding of the present invention will be described in detail.
As described above, the resin composition for molding an automobile side molding of the present invention comprises (A) a propylene-based block copolymer of 77.92 to 81.94% by weight, (B) an ethylene-based elastomer of 9 to 11% by weight, (C ) 9 to 11% by weight of talc having an average particle size of 3.0 μm or less, and (D) 0.06 to 0.08% by weight of molecular weight depressant.
[0010]
Here, the propylene-based block copolymer (A) has a weight ratio (W _PP / W _RC ) of a homopolymer component and a copolymer component from the viewpoint of imparting appropriate flexibility to the obtained resin composition for an automobile side molding. Is controlled to 1.9 to 2.1.
When W _PP / W _RC is less than 1.9, sufficient flexibility can be imparted to the resulting resin composition for automobile side molding, but material stickiness occurs. On the other hand, W the _{PP /} W _RC exceeds 2.1, although the occurrence of stickiness in the automotive side moldings resin composition obtained is low, flexibility is insufficient.
[0011]
In addition, the intrinsic viscosity [η] _PP and [η] _RC of the homopolymer component and the copolymer component are both 1.8 to 2.0 dl / g.
When the intrinsic viscosity exceeds 2.0, in order to ensure the fluidity of the resulting resin composition for automobile side molding, it is necessary to blend a large amount of molecular weight depressant (D). The low molecular weight copolymer component bleeds out, and the product quality is significantly deteriorated.
[0012]
Next, the ethylene-based elastomer (B) is an elastomer exhibiting low crystallinity or non-crystallinity, and specifically includes an ethylene / propylene copolymer rubber, an ethylene / butene copolymer rubber, and an ethylene / octene copolymer. A coalescence rubber etc. can be mentioned, The compounding quantity is adjusted to 9-11 weight%.
If it exceeds 11% by weight, the resulting resin composition for automobile side molding is excellent in terms of flexibility and dimensional stability, but stickiness of the material occurs. If it is less than 9% by weight, the material is less sticky, but the flexibility and dimensional stability are insufficient.
[0013]
The melt flow rate (hereinafter abbreviated as “MFR”) of the ethylene-based elastomer (B) is 10 g / 10 min or more from the viewpoint of balancing the fluidity and stickiness of the obtained resin composition for automobile side moldings ( 230 ° C .; 21.18 N), more preferably 10 to 30 g / 10 min (230 ° C .; 21.18 N), and still more preferably 20 to 30 g / 10 min (230 ° C .; 21.18 N). .
When MFR is less than 10 g / 10 min, the fluidity of the obtained resin composition for side molding is lowered.
[0014]
Moreover, the compounding quantity of talc (C) whose average particle diameter is 3.0 micrometers or less is adjusted to 9-11 weight%.
If it exceeds 11% by weight, the dimensional stability of the obtained resin composition for an automobile side molding becomes extremely good, but the flexibility of the material itself is insufficient.
In addition, when the average particle diameter of talc exceeds 3.0 μm, problems such as generation of a flow mark occur in the obtained automobile side molding. .
[0015]
Furthermore, examples of the molecular weight depressant (D) include organic peroxides. Specifically, benzoyl peroxide, t-butyl perbenzoate, t-butyl peracetate, t-butyl peroxyisopropyl carbonate, 2, 5-Di-methyl-2,5-di- (benzoylperoxy) hexane, 2,5-di-methyl-2,5-di- (benzoylperoxy) hexyne-3, t-butyl-di-peradipate , T-butylperoxy-3,5,5-trimethylhexanoate, methyl-ethylketone peroxide, cyclohexanone peroxide, di-t-butyl peroxide, dicumyl peroxide, 2,5-di-methyl -2,5-di- (t-butylperoxy) hexane, 2,5-di-methyl-2,5-di- (t-butylperoxy) ) Hexin-3, 1,3-bis- (t-butylperoxyisopropyl) benzene, t-butylcumyl peroxide, 1,1-bis- (t-butylperoxy) -3,3,5-trimethyl Cyclohexane, 1,1-bis- (t-butylperoxy) cyclohexane, 2,2-bis- (t-butylperoxy) butane, p-menthane hydroperoxide, di-isopropylbenzene hydroperoxide, cumene hydroper Oxide, t-butyl hydroperoxide, p-cymene hydroperoxide, 1,1,3,3-tetra-methylbutyl hydroperoxide and 2,5-di-methyl-2,5-di- (hydroperoxy) ) Hexane etc. can be exemplified, and these can be used alone or in any combination of two or more. It is also possible to use.
[0016]
Moreover, the compounding quantity of the organic peroxide which is the said molecular weight depressant is adjusted to 0.06-0.08 weight%.
If it exceeds 0.08% by weight, the fluidity of the resulting resin composition for an automobile side molding is greatly improved, but the balance with the stickiness is lost, or the copolymer component having a low molecular weight is bleeded on the surface of the automobile side molding. Or the quality of the product deteriorates significantly.
[0017]
In addition, although the resin composition for automobile side moldings of the present invention includes the above-described components (A) to (D) as essential components, a known additive used in conventional polyolefins is blended as necessary. May be.
Examples of such additives include antioxidants, dispersants, ultraviolet absorbers, light stabilizers, neutralizers, antistatic agents, pigments and lubricants.
[0018]
Hereinafter, the manufacturing method of the resin composition for molding an automobile side molding of the present invention will be described.
In the propylene-based block copolymer (A), first, a crystalline homopolymer component is generated, and the intrinsic viscosity ([η] _PP ) of the polymer component is directly measured. Subsequently, the intrinsic viscosity ([η] _RC ) of the copolymer component, which is a propylene-ethylene random copolymer produced, is measured by the intrinsic viscosity [η] _WHOLE of the entire propylene-based block copolymer (A) to be obtained. Measure and subtract the homopolymer component's intrinsic viscosity [η] _PP multiplied by the homopolymer component's weight fraction, and divide this by the total composition, ie, the copolymer component's fraction. [Η] _RC is determined.
That is, the following formula (1)
[0019]
[Expression 1]

[0020]
In addition, the fraction ( _WRC / 100) of the copolymer component in the formula (1) can be obtained by a conventionally known infrared analysis method or the like.
[0021]
The propylene-based block copolymer (A) may be produced by any method. For example, the propylene-based block copolymer (A) may be obtained as a blend obtained by adding EPR having the intrinsic viscosity defined in the present invention to a homopolymer. Further, an ethylene-propylene random copolymer polymerized using a titanium-containing solid catalyst component may be added to a homopolymer to produce a blend.
However, from the viewpoint of economy, it is most preferable to obtain by a method in which a homopolymer component is polymerized and subsequently a copolymer component is continuously produced.
[0022]
The resin composition for molding an automobile side molding of the present invention uses a kneader known in the art such as a uniaxial or biaxial extruder, a Banbury mixer, a kneader or a roll, and the various components (A) to (D) and It can be produced by melting and kneading various additives as required.
[0023]
Moreover, the automobile side molding of the present invention is obtained by applying various molding methods such as injection molding to the above-described resin composition for an automobile side molding of the present invention.
Specifically, as shown in FIG. 7, it is used as a fender side molding 9, a front side molding 10, and a rear side molding 11.
[0024]
【Example】
EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, these are for demonstrating this invention concretely, This invention is not limited to these Examples.
In the following examples and comparative examples, the following methods were used as evaluation methods for the obtained molded products.
[0025]
<Evaluation method>
Basic physical properties ◆ Melt flow rate (MFR)
The measurement was performed at 230 ° C. and a load of 21.18 N according to the method defined in JIS K6758. (Unit: g / 10min)
[0026]
◆ Flexural modulus According to the method specified in JIS K7203, the measurement was performed at a measurement temperature of 23 ° C., a span length of 60 mm, and a load speed of 1.5 mm / min (unit: MPa).
This was carried out in accordance with the method defined in JIS K6758.
[0027]
◆ Linear expansion coefficient (dimensional stability)
The temperature was increased at a rate of 5 ° C./min, a load of 2 g, and a measurement range of −30 ° C. to 80 ° C. (unit: × 10 ⁻⁵ cm / cm · ° C.) according to the method defined in JIS K7197.
In this evaluation, it can be said that the smaller the linear expansion coefficient, the better the dimensional stability.
[0028]
◆ Static friction coefficient It was carried out in accordance with the method specified in ASTM D1894 (unit: dimensionless).
[0029]
◆ Bleed test A flat test piece of 100 mm × 100 mm × 2 mm was conditioned for 720 hours in a room with a humidity of 50% and a room temperature of 23 ° C., and “×” Those that did not occur were marked with “◯”.
[0030]
Product Test ◆ Side Mold Injection Molding and Evaluation of Release Properties The automobile side molding uses an injection molding machine with a clamping force of 850 t in the mold shown in FIG. 1 and FIG. A resin was injected from one end of the film gate 4 into the mold cavity 3 from the terminal, and obtained by injection molding.
At that time, when the side molding (see FIGS. 3 and 4) can be easily taken out from the cavity mold 1 or the core mold 2, the release property is “◯”, and when it cannot be taken out, the mold is released. The sex was “x”.
In addition, as various conditions at the time of molding,
Injection pressure: 800 kg / cm ²
Injection speed: 40 mm / sec Cylinder Setting temperature: 210 ° C
Hot runner setting temperature: 220 ° C
It was adopted.
[0031]
◆ Appearance (flow mark) test Visually evaluate the appearance of the side moldings obtained by injection molding, confirm the presence or absence of the flow mark 8, and if there is no flow mark (see Fig. 5) ”, The occurrence confirmed (see FIG. 6) was marked“ x ”.
[0032]
◆ Adhesion test of side molding on car body The rib part 7 of the side molding molded product obtained by injection molding and a steel plate are pasted through an acrylic double-sided tape (manufactured by Sumitomo 3M).
Next, kerosene heated to 60 ° C. is sprayed on the upper surface of the side molding for 1 minute, and then cooled for 2 hours in a thermostatic bath previously held at −30 ° C., and further kept at 80 ° C. Heat treatment is carried out for 2 hours, and this cooling treatment and heat treatment are repeated 10 times, and the side molding is not “peeled” from the steel plate, and “×” is peeled off. did.
[0033]
The materials and characteristics of the blending components used in the following Examples and Comparative Examples are shown below (see Table 1).
<Composition ingredients>
● PP-1
[Η] _RC 1.9 dl / g
[Η] _PP 1.9 dl / g
W _PP / W _RC 2.0
A propylene-based block copolymer.
[0034]
● PP-2
[Η] _RC 3.0 dl / g
[Η] _PP 3.0 dl / g
W _PP / W _RC 2.0
A propylene-based block copolymer.
[0035]
● PP-3
[Η] _RC 2.0 dl / g
[Η] _PP 2.0 dl / g
W _PP / W _RC 1.5
A propylene-based block copolymer.
[0036]
● PP-4
[Η] _RC 1.5 dl / g
[Η] _PP 1.5 dl / g
W _PP / W _RC 2.1
A propylene-based block copolymer.
[0037]
● PP-5
[Η] _RC 2.1 dl / g
[Η] _PP 2.1 dl / g
W _PP / W _RC 3.0
A propylene-based block copolymer.
[0038]
Molecular weight depressant 1,3-bis (t-butyl-peroxyisopropyl) benzene
● Ethylene-based elastomer-1
Ethylene-octene copolymer rubber having an octene content of 20% by weight and an MFR of 27 g / 10 min (230 ° C .; 21.18 N)
Ethylene / octene copolymer rubber having an octene content of 24% by weight and an MFR of 2 g / 10 min (230 ° C .; 21.18 N)
● Talc-1
Talc with an average particle size of 2.0 μm Talc-2
Talc with an average particle size of 4.8 μm
(Example 1, Comparative Examples 1-9)
The composition shown in Table 1 described later (compounding ratio:% by weight) was employed, and PP-1 to 5, a molecular weight depressant, an ethylene elastomer, and talc were blended to obtain a composition. Further, 100 parts by weight of the composition, 0.1 part by weight of a phenolic antioxidant and 0.1 part by weight of calcium stearate were mixed for 3 minutes at room temperature with a high-speed stirring mixer (Hensel mixer, trade name). A composition was obtained, and the composition was granulated using an extrusion granulator (NVC-50 manufactured by Nakatani Machinery Co., Ltd.) having a screw diameter of 50 mm and a cylinder set temperature of 200 ° C. to obtain a pellet-shaped composition.
Using this composition, a test piece was prepared under the conditions of a cylinder temperature of 230 ° C., an injection speed of 30 mm / second, and a mold water flow temperature of 50 ° C. using an injection molding machine with a clamping force of 100 t (IS-100, manufactured by Toshiba Machine). The test piece was conditioned for 72 hours in a room with a humidity of 50% and a room temperature of 23 ° C. Next, MFR, flexural modulus, linear expansion coefficient, static friction coefficient, bleed test were evaluated, and further product tests were performed. The evaluation results are shown in Table 1.
[0042]
[Table 1]

[0043]
As is clear from Table 1, Example 1 belonging to the scope of the present invention has less stickiness and bleeding, and is excellent in all of flexibility, dimensional stability and appearance.
[0044]
【The invention's effect】
As described above, according to the present invention, the polymerization ratio of propylene homopolymer component and ethylene-propylene copolymer component and the intrinsic viscosity of each component are controlled, and a specific ethylene elastomer, talc and molecular weight are controlled. Since the depressant was appropriately selected and used, a resin composition for molding an automobile side molding excellent in flexibility, dimensional stability, appearance and economy, and having less stickiness, and an automobile side molding using the same Can be provided.
That is, since the resin composition for molding an automobile side molding of the present invention has such excellent characteristics, the automobile side molding obtained as a molding raw material is used as an automobile side molding as shown in FIG. Is preferred.
[0045]
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a mold used for injection molding of an automobile side molding.
FIG. 2 is a perspective view of a cavity mold used for injection molding of an automobile side molding.
FIG. 3 is a bottom view of the automobile side molding.
FIG. 4 is a cross-sectional view of an automobile side molding.
FIG. 5 is a top view of an automobile side molding.
FIG. 6 is a top view showing a flow mark portion of the automobile side molding.
FIG. 7 is a side view showing an automobile using an automobile side molding.
[Explanation of symbols]
1 ... cavity mold part 2 ... core mold part 3 ... cavity part 4 ... gate part 5 .... Runner part 6 ... Hot runner part 7 ... Rib part 8 ... Flow mark part 9 ... ... Fender side molding 10 ... Front door side molding 11 ... Rear door side molding

Claims (3)

(A) 77.92 to 81.94% by weight of a propylene-based block copolymer, (B) 9 to 11% by weight of an ethylene-based elastomer, and (C) talc 9 to 11 having an average particle size of 3.0 μm or less. A resin composition for molding an automobile side molding, which comprises, by weight, 0.06 to 0.08% by weight of (D) molecular weight depressant,
The propylene-based block copolymer (A) includes a homopolymer component of propylene and a copolymer component of ethylene-propylene,
From the intrinsic viscosity [η] _{PP of} the homopolymer component and the intrinsic viscosity of the entire propylene-based block copolymer (A), the weight fraction of the homopolymer component and the intrinsic viscosity [η] _{PP of the} homopolymer component [Η] _RC, which is the quotient obtained by dividing the difference between the product and the weight fraction of the copolymer component, by 1.8 to 2.0 dl / g,
A resin composition for molding an automobile side molding, wherein the weight ratio (W _PP / W _RC ) of the weight W _PP of the homopolymer component to the weight W _{RC of the} copolymer component is 1.9 to 2.1. .   The resin composition for molding an automobile side molding according to claim 1, wherein the melt flow rate of the ethylene-based elastomer (B) is 10 g / 10 min or more (230 ° C; 21.18 N).   An automobile side molding obtained by using the molding resin composition according to claim 1.

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