JP3541512B2 - Low gloss and heat resistant resin composition with excellent flow / impact balance - Google Patents

Description

【００４２】
製造例２：グラフト共重合体の合成
撹拌機付きステンレス重合槽に、規定量の水とラテックスを仕込み６０℃に昇温した後、水に溶解したフラクトース、ピロリン酸ナトリウム及び硫酸第一鉄を添加した。同時にＣＨＰとスチレン、アクリロニトリル、ＴＤＭの混合溶液を２系列で７０分かけて添加し、最終的に１５０分かけて重合を完結させた。重合温度の設定は以下の通りである。
【００４３】
０〜３０分：６０℃一定
３０〜７０分：６０℃から７１℃に昇温
７０〜１５０分：７１℃一定
重合後、酸化防止剤を添加し、硫酸にて凝固を行い、洗浄、脱水、乾燥の工程を経て表２に示すグラフト共重合体ＨＲＧ−１〜４を得た。
【００４４】
【表２】

【００４５】
製造例３：低分子量硬質共重合体の合成
表３に示すような仕込み組成で通常の懸濁重合を行い、目的のＮ−ＰＭＩ含有量及び分子量を有する低分子量硬質共重合体：Ｒｉｇｉｄ−１〜６を得た。
【００４６】
【表３】

【００４７】
実施例及び比較例
上記方法により得られたバルク共重合体、グラフト共重合体及び低分子量硬質共重合体を、表４〜７に示す配合（重量部）で、１．０重量部のＮ，Ｎ’−エチレンビスステアリルアミド（ＥＢＳ−ｗａｘ）と共にバンバリーミキサーにて混練した後、ペレット化した。得られたサンプルは、４オンス射出成形機により２４０℃で成形した。
【００４８】
各サンプルの特性を下記方法で試験し、結果を表４〜７に示した。
【００４９】
ＳＳＰ(kg/cm²)：日本精鋼社製４オンス射出成形機により２４０℃で引張り用テストピースを成形する際の最低充填圧力（ゲージ圧）で表される。（ショート・ショット・ポイントと呼び材料の実際上の成形における流動特性を良く代表することが知られている。）
アイゾット衝撃値(kg-cm/cm)：ＡＳＴＭ（Ｄ２５６）１／８インチ・ノッチ付きアイゾット、測定温度は２３℃
落錘衝撃値(kg-mm):島津ハイドロショットＨＴＭ−１を用い、下記条件で行った。
撃芯速度：５．０ｍ／ｓｅｃ
プローブ：１／４”Ｒ
試料ホルダー：１”Φ
測定温度：２３℃
光沢：スガ試験機製デジタル変角光計ＵＧＶ−５Ｄを用い、入射角６０°、反射角６０°での反射率の測定を行った。
【００５０】
光沢勾配：ＳＳＰの射出圧力で成形したサンプルの光沢値とＳＳＰ＋１０ｋｇ／ｃｍ² の射出圧力で成形したサンプルの光沢値の差から求められる。即ち、この差が大きければ射出圧力変動に対する光沢安定性が悪いことになる。
【００５１】
表面外観：５０×５０×３．２ｍｍの平板成形体にて目視評価により成形体表面の外観を下記評価基準で判定した。
【００５２】
○：光沢ムラもフローマークもなく良好
△：光沢ムラ又はフローマークがいくらか認められる
×：光沢ムラ又はフローマークが著しい
熱変形温度（℃）：ＡＳＴＭ（Ｄ６４８−５６）に準じた。
【００５３】
【表４】

【００５４】
【表５】

【００５５】
【表６】

【００５６】
【表７】

【００５７】
【発明の効果】
以上詳述した通り、本発明によれば、フロー・インパクトバランスに優れ、射出成形条件の変化に対しても安定した低光沢を与える上に、表面外観、耐衝撃強度、成形性、耐熱性に優れた樹脂組成物が提供される。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a heat-resistant resin composition having an excellent flow / impact balance and giving a stable low gloss to changes in injection molding conditions.
[0002]
[Prior art]
ABS (acrylonitrile-butadiene-styrene) resin is excellent in the balance of physical properties such as processability and impact resistance, and in the appearance of molded products such as luster. Therefore, molding materials for interior and exterior parts of automobiles, home appliances, office equipment, etc. As widely used.
[0003]
In recent years, there has been an increasing demand for matting materials in automobile interior parts, in that characteristics such as moldability, heat resistance, etc. are imparted, and at the same time, glare of the sun is given to the driver and a calm texture is preferred. I have. In the past, in automotive interior parts, the emphasis was placed on the heat resistance of materials, and there was a history of reducing the development of high heat-resistant materials, but recently, some heat resistance has been maintained. As described above, with the increase in size and complexity of molded products, the development has been focused on moldability and the stability of the matte state. However, conventionally, it has been extremely difficult to improve the moldability of the material, that is, the fluidity, while securing a certain degree of heat resistance and impact strength. For example, it has been difficult to suppress the gloss fluctuation due to a change in the injection pressure.
[0004]
Japanese Patent Publication No. 1-34461 and Japanese Patent Publication No. Hei 5-506051 disclose that rubber is made bimodal with a heat-resistant material containing a maleimide-based copolymer to improve drop weight impact strength and tensile strength. It is disclosed that the material is intended to be used, but the fluidity of the resin is not discussed at all, and it cannot be said that the material has sufficient performance from the viewpoint of flow impact balance.
[0005]
On the other hand, various matting methods for ABS resin have been proposed, including a method of adding an inorganic substance such as calcium, a method of adding a rubbery polymer, a method of using an ethylenically unsaturated carboxylic acid, and a method of containing an epoxy group. Methods using olefin copolymers and the like are well known. However, although all of the conventional methods can provide a certain matting effect, it has not been able to keep the gloss fluctuation accompanying a change in injection molding conditions, for example, the injection pressure, low while maintaining a good flow / impact balance.
[0006]
[Problems to be solved by the invention]
As described above, in the past, the heat resistance has an excellent flow-impact balance, and can obtain a good low-gloss molded product stably and reliably even when the injection molding conditions such as the injection pressure are changed. No resin composition is provided.
[0007]
The present invention has been made in view of the above conventional circumstances, and has as its object to provide a low-gloss, heat-resistant resin composition having an excellent flow-impact balance.
[0008]
[Means for Solving the Problems]
The low gloss and heat resistant resin composition having an excellent flow / impact balance of the present invention is
A bulk polymer of a styrene-based monomer, an unsaturated nitrile-based monomer, a maleimide-based monomer and a rubber-like polymer, wherein the content of the maleimide-based monomer is 5 to 15% by weight, Bulk copolymer having a volume average particle diameter of 1.0 to 5.0 μm and a rubbery polymer content of 10 to 15% by weight: 10 to 35 parts by weight of a styrene monomer and an unsaturated nitrile monomer Graft copolymer having a volume average particle diameter of 0.06 to 0.4 μm and a graft ratio of 70 to 150%. A mixture of (A) and a graft copolymer (B) having a volume average particle diameter of the rubber-like polymer of 0.05 to 0.2 μm and a graft ratio of 20 to 60%. , Graft copolymer (B) / graft copolymer (A) = 0.4 to 2.0, a hard copolymer obtained by copolymerizing 25 to 55 parts by weight of a styrene-based monomer, an unsaturated nitrile-based monomer and a maleimide-based monomer, It is characterized by containing 10 to 60 parts by weight of a low molecular weight hard copolymer having a maleimide monomer content of 5 to 20% by weight and a weight average molecular weight of 40,000 to 120,000.
[0009]
That is, the present inventors have intensively studied to obtain a low-gloss, heat-resistant resin composition having an excellent flow / impact balance, and as a result, a bulk copolymer having a structure restricted to certain specific conditions and two types of bulk copolymers By blending graft copolymers with different graft ratios and rubber particle diameters with low-molecular-weight hard copolymers with a specific structure at a specific ratio, excellent flow / impact balance is exhibited and changes in injection molding conditions It has been found that a heat-resistant resin composition which gives a stable low gloss to the resin can be obtained.
[0010]
Although the details of the mechanism of action in the present invention are not clear, a synergistic effect appears in the impact energy absorption effect by blending the emulsion graft copolymer having a small particle size with the bulk copolymer having a large particle size, and the impact resistance is improved. It is conceivable that the strength increases. Moreover, in this system, even if a copolymer having a much smaller molecular weight than the hard copolymer usually used for the matrix side is used, it does not significantly affect the shock absorbing effect, and as a result, the flow of the blend is reduced.・ It is estimated that the impact balance will be improved. Furthermore, by blending two types of graft copolymers having different graft ratios as an emulsion graft copolymer having a small particle size, rubber particles having a low graft ratio cause some aggregation during molding, and a bulk copolymer is formed. It is considered that the interaction with the large particle diameter rubber has an unexpected effect of suppressing a gloss variation due to a change in injection pressure during injection molding.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described in detail.
[0012]
The low-gloss, heat-resistant resin composition having an excellent flow / impact balance of the present invention contains the bulk copolymer, the graft copolymer mixture and the low-molecular-weight hard copolymer having the above-mentioned specific constitution.
[0013]
In the present invention, the following styrene-based monomers and unsaturated nitrile-based monomers used as a raw material for synthesizing a bulk copolymer, a graft copolymer mixture and a low-molecular-weight hard copolymer include the following. Can be
[0014]
Examples of the styrene monomer include styrene, α-methylstyrene, p-methylstyrene, t-butylstyrene and the like, and styrene is most preferably used.
[0015]
Examples of the unsaturated nitrile monomer include acrylonitrile, methacrylonitrile, ethacrylonitrile, fumaronitrile, and the like, and it is preferable to use acrylonitrile.
[0016]
In the present invention, the rubbery polymer used as a raw material for synthesizing the bulk copolymer and the graft copolymer mixture includes polybutadiene rubber (PBD), styrene butadiene rubber (SBR), ethylene propylene diene rubber (EPDM), Ethylene-propylene rubber (EPR), butadiene-acrylonitrile rubber (NBR), isoprene rubber (IR), acrylic rubber (AR), and the like can be used.
[0017]
Furthermore, N-phenylmaleimide is most commonly used as a maleimide-based monomer used as a raw material for synthesizing a bulk copolymer and a low-molecular-weight hard copolymer, but other maleimide, N-alkylmaleimide, N- An aromatic derivative maleimide or the like can be used.
[0018]
The bulk copolymer according to the present invention is obtained by bulk polymerizing a styrene-based monomer, an unsaturated nitrile-based monomer, a maleimide-based monomer, and a rubber-like polymer. Is 5 to 15% by weight, the volume average particle diameter (Dv) of the rubbery polymer is 1.0 to 5.0 μm, and the content of the rubbery polymer is 10 to 15% by weight.
[0019]
When the Dv of the rubbery polymer of the bulk copolymer is less than 1.0 μm, the flow impact balance of the obtained composition is deteriorated, the gloss increases, and the gloss gradient increases. If Dv exceeds 5.0 μm, the surface appearance will be significantly deteriorated. When the content of the rubber-like polymer is less than 10% by weight, the impact strength of the obtained composition is inferior, and when it exceeds 15% by weight, the viscosity of the rubber elastic solution becomes high and it becomes difficult to control the polymerization reaction, The surface appearance of the resulting composition deteriorates. Further, when the content of the maleimide-based monomer is less than 5% by weight, the obtained composition has poor impact strength and does not show sufficient heat resistance. When the content exceeds 15% by weight, the flow / impact balance is remarkably deteriorated, The surface appearance also deteriorates.
[0020]
The weight ratio of the unsaturated nitrile monomer to the styrene monomer in the bulk copolymer is preferably in the range of 20/80 to 35/65.
[0021]
Further, the rubber-like polymer preferably has a number average particle diameter (Dn) of 0.6 to 2.0 μm and a ratio of the volume average particle diameter (Dv) to the number average particle diameter (Dn) of 1.5 to 2. .5.
[0022]
The graft copolymer mixture according to the present invention is obtained by emulsion polymerization of a styrene-based monomer, an unsaturated nitrile-based monomer, and a rubber-like polymer, and the rubber-like polymer has a Dv of 0.06. A graft copolymer (A) having a graft ratio of 70 to 150% and a rubber-like polymer having a Dv of 0.05 to 0.2 μm and a graft ratio of 20 to 60%. A mixture with a certain graft copolymer (B), the weight ratio of which is a graft copolymer (B) / graft copolymer (A) = 0.4 to 1.0.
[0023]
When the Dv of the graft copolymer (A) is less than 0.06 μm, the flow impact balance of the obtained composition is deteriorated, and when it exceeds 0.4 μm, the flow impact balance is similarly deteriorated. Further, when the graft ratio of the graft copolymer (A) is less than 70%, the impact strength of the obtained composition is inferior, and when it exceeds 150%, the flow impact balance is deteriorated.
[0024]
On the other hand, when the Dv of the graft copolymer (B) is less than 0.05 μm, the resulting composition has a large gloss gradient and the flow / impact balance is deteriorated. If Dv exceeds 0.2 μm, the gloss gradient similarly increases, and the flow / impact balance deteriorates. Further, when the graft ratio of the graft copolymer (B) is less than 20%, the surface appearance of the obtained composition is deteriorated, and when it exceeds 60%, the gloss gradient is increased and the gloss is increased.
[0025]
If the mixing ratio (weight ratio) of the graft copolymer (A) and the graft copolymer (B): (B) / (A) is less than 0.4, the resulting composition has a large gloss gradient. , 1.0, the flow impact balance deteriorates.
[0026]
The graft copolymer (A) has a styrene monomer content of 65 to 80% by weight, an unsaturated nitrile monomer content of 35 to 20% by weight, and a rubbery polymer content of 35 to 35% by weight. It is preferably about 50% by weight.
[0027]
The graft copolymer (B) has a styrene-based monomer content of 65 to 80% by weight, an unsaturated nitrile-based monomer content of 35 to 20% by weight, and a rubber-like polymer content of 55%. It is preferably about 70% by weight.
[0028]
The low-molecular-weight hard copolymer according to the present invention is obtained by copolymerizing a styrene monomer, an unsaturated nitrile monomer, and a maleimide monomer, and contains a maleimide monomer. It has an amount of 5 to 20% by weight and a weight average molecular weight of 40,000 to 120,000.
[0029]
If the maleimide monomer content of the low molecular weight hard copolymer is less than 5% by weight, the resulting composition does not exhibit sufficient heat resistance, and if it exceeds 20% by weight, the flow impact balance and the surface appearance deteriorate. I do. When the weight average molecular weight of the low molecular weight hard copolymer is less than 40,000, sufficient impact strength is not exhibited, and when it exceeds 120,000, the flow impact balance is deteriorated.
[0030]
In addition, it is preferable that the content of the styrene-based monomer of the low molecular weight hard copolymer is 65 to 80% by weight, and the content of the unsaturated nitrile-based monomer is 35 to 20% by weight.
[0031]
The low gloss and heat resistant resin composition having an excellent flow impact balance of the present invention comprises such a bulk copolymer, a graft copolymer mixture and a low molecular weight hard copolymer, per 100 parts by weight of the composition, Bulk copolymer: 10 to 35 parts by weight, graft copolymer mixture: 25 to 55 parts by weight, and low molecular weight hard copolymer: 10 to 60 parts by weight.
[0032]
When the content of the bulk copolymer is less than 10 parts by weight, the flow / impact balance of the obtained composition is deteriorated, and the gloss is increased. If the content exceeds 35 parts by weight, the flow / impact balance will deteriorate.
[0033]
When the content of the graft copolymer mixture is less than 25 parts by weight, the gloss gradient becomes large, and when it exceeds 55 parts by weight, the flow impact balance is deteriorated.
[0034]
On the other hand, if the content of the low molecular weight hard copolymer is less than 10 parts by weight, sufficient heat resistance cannot be obtained and the flow impact balance deteriorates, and if it exceeds 60 parts by weight, the flow impact balance remarkably deteriorates.
[0035]
The low gloss and heat resistant resin composition having an excellent flow / impact balance of the present invention is obtained by kneading a bulk copolymer, a graft copolymer mixture and a low molecular weight hard copolymer, which are produced according to a conventional method, in a predetermined blend. Can be easily prepared. The kneaded material is pelletized according to a conventional method and used as a forming raw material.
[0036]
【Example】
Hereinafter, the present invention will be described more specifically with reference to Production Examples, Examples, and Comparative Examples.
[0037]
In the following, “%” in the raw material composition, composition, etc. indicates “% by weight”.
[0038]
Production Example 1: Synthesis of Bulk Copolymer Bulk copolymers Bulk-1 to Bulk-7 were produced using a bulk polymerization apparatus composed of three reactors of 4 liters of a completely uniform mixing type.
[0039]
First, a rubber is dissolved in a required amount of ST (styrene), and AN (acrylonitrile), N-PMI (N-phenylmaleimide), an initiator and a chain transfer agent (TDM: t-dodecylmercaptan) are added, and the mixture is continuously fed to the reactor. did. After inversion of the rubber occurred in the first-stage reactor, polymerization was carried out to a monomer conversion rate of 85% in the second-stage and third-stage reactors, and residual monomers were removed by a deaerator. Further, the amount of the monomer was divided as required, and a solution of N-PMI, AN, and ST and a chain transfer agent (TDM: t-dodecylmercaptan) were fed together before the second-stage reactor. The polymerization temperature was 1st stage: 80 ° C., 2nd stage: 120 ° C., 3rd stage: 160 ° C., and the rubber particle diameter in the polymer was determined by the amount of TDM fed to each reactor and the stirring speed of each reactor. Was adjusted to an appropriate particle size.
[0040]
Table 1 shows the rubber type and the rubber content, the measured N-PMI content, and the rubber particle diameter of the sample obtained by the main polymerization. Note that the AN / ST weight ratio of the bulk copolymer was 24/76 in each case.
[0041]
[Table 1]

[0042]
Production Example 2: Synthesis of graft copolymer A specified amount of water and latex were charged into a stainless steel polymerization tank equipped with a stirrer, heated to 60 ° C, and fructose, sodium pyrophosphate and ferrous sulfate dissolved in water were added. did. At the same time, a mixed solution of CHP, styrene, acrylonitrile, and TDM was added in two lines over 70 minutes, and finally polymerization was completed over 150 minutes. The setting of the polymerization temperature is as follows.
[0043]
0 to 30 minutes: constant at 60 ° C. 30 to 70 minutes: heating from 60 ° C. to 71 ° C. 70 to 150 minutes: constant at 71 ° C. After polymerization, add an antioxidant, coagulate with sulfuric acid, wash, dehydrate Through a drying step, graft copolymers HRG-1 to HRG-4 shown in Table 2 were obtained.
[0044]
[Table 2]

[0045]
Production Example 3: Synthesis of Low-Molecular-Weight Hard Copolymer A normal low-molecular-weight hard copolymer having the target N-PMI content and molecular weight was obtained by performing ordinary suspension polymerization with a charged composition as shown in Table 3. ~ 6.
[0046]
[Table 3]

[0047]
Examples and Comparative Examples A bulk copolymer, a graft copolymer and a low-molecular-weight hard copolymer obtained by the above method were mixed with 1.0 part by weight of N, After kneading with N'-ethylenebisstearylamide (EBS-wax) using a Banbury mixer, the mixture was pelletized. The obtained sample was molded at 240 ° C. using a 4 oz. Injection molding machine.
[0048]
The characteristics of each sample were tested by the following methods, and the results are shown in Tables 4 to 7.
[0049]
SSP (kg / cm ² ): Expressed as the minimum filling pressure (gauge pressure) when forming a tensile test piece at 240 ° C. using a 4-ounce injection molding machine manufactured by Nippon Seiko Steel Co., Ltd. (It is known that the short shot point is a good representative of the flow characteristics in the actual molding of the material.)
Izod impact value (kg-cm / cm): ASTM (D256) 1/8 inch notched Izod, measuring temperature 23 ° C
Drop weight impact value (kg-mm): Performed under the following conditions using Shimadzu Hydroshot HTM-1.
Shooting speed: 5.0 m / sec
Probe: 1/4 "R
Sample holder: 1 "Φ
Measurement temperature: 23 ° C
Gloss: The reflectance was measured at an incident angle of 60 ° and a reflection angle of 60 ° using a digital goniophotometer UGV-5D manufactured by Suga Test Instruments.
[0050]
Gloss gradient: Determined from the difference between the gloss value of a sample molded at an injection pressure of SSP and the gloss value of a sample molded at an injection pressure of SSP + 10 kg / cm ² . That is, if the difference is large, the gloss stability against the fluctuation of the injection pressure is poor.
[0051]
Surface appearance: The appearance of the surface of the molded body was determined by visual evaluation using a 50 × 50 × 3.2 mm flat molded body according to the following evaluation criteria.
[0052]
：: Good without gloss unevenness or flow mark Δ: Some gloss unevenness or flow mark observed X: Significant unevenness in gloss or flow mark Thermal deformation temperature (° C.): According to ASTM (D648-56).
[0053]
[Table 4]

[0054]
[Table 5]

[0055]
[Table 6]

[0056]
[Table 7]

[0057]
【The invention's effect】
As described in detail above, according to the present invention, in addition to providing excellent flow impact balance, stable low gloss even with changes in injection molding conditions, surface appearance, impact strength, moldability, heat resistance An excellent resin composition is provided.

Claims (1)

A bulk polymer of a styrene-based monomer, an unsaturated nitrile-based monomer, a maleimide-based monomer and a rubber-like polymer, wherein the content of the maleimide-based monomer is 5 to 15% by weight, Bulk copolymer having a volume average particle diameter of 1.0 to 5.0 μm and a rubbery polymer content of 10 to 15% by weight: 10 to 35 parts by weight of a styrene monomer and an unsaturated nitrile monomer Graft copolymer having a volume average particle diameter of 0.06 to 0.4 μm and a graft ratio of 70 to 150%. A mixture of (A) and a graft copolymer (B) having a volume average particle diameter of the rubber-like polymer of 0.05 to 0.2 μm and a graft ratio of 20 to 60%. , Graft copolymer (B) / graft copolymer (A) = 0.4 to 2.0, a hard copolymer obtained by copolymerizing 25 to 55 parts by weight of a styrene-based monomer, an unsaturated nitrile-based monomer and a maleimide-based monomer, Excellent flow impact, characterized by containing 10 to 60 parts by weight of a low molecular weight hard copolymer having a maleimide monomer content of 5 to 20% by weight and a weight average molecular weight of 40,000 to 120,000. A low gloss, heat resistant resin composition with a balance.