【発明の詳細な説明】[Detailed description of the invention]
ABS樹脂等のゴム質重合体は耐衝撃性、耐熱
性、加工性が良好であり、他の物性においても大
きな欠点がないため、電気機器部品、自動車部
品、家具、建材などに広く使用されている。
しかしながら近時、これらの用途分野における
火災時の安全性が重要視されてくるに至つてゴム
質重合体の易燃性が大きな欠点とされるようにな
つた。
従来ゴム質重合体に難燃性を付与する方法とし
て難燃剤をブレンドする方法が提案されている
が、該方法は難燃剤の毒性問題に加えて、ゴム質
重合体の物性が低下すると云う致命的な欠点があ
つた。
また、ゴム質重合体に塩化ビニル樹脂をブレン
ドすることも提案されているが、この場合ゴム質
重合体の耐熱性および成形性が著しく低下しゴム
質重合体本来の特性が著しく損なわれる欠点があ
る。（特開昭48―11341号公報参照）。
さらにゴム質重合体に塩素化塩化ビニル樹脂を
ブレンドすることも試みられたが、これらは高重
合度の塩素化塩化ビニル樹脂が用いられていた。
一般に塩素化塩化ビニル樹脂は成形用に供される
塩化ビニル樹脂を塩素化して調製されている。す
なわちまず塩化ビニルモノマーを油溶性重合触媒
および分散剤の存在下に水性媒体中で懸濁重合さ
せて塩化ビニル樹脂を得、このものをさらに塩素
化して塩素化塩化ビニル樹脂の調製を行つてい
る。しかしながらかかる製造法に由来する塩素化
塩化ビニル樹脂をゴム質重合体とブレンドした場
合一応難燃性を付与することはできるが、反面加
工性が著しく低下し、ゴム質重合体成形用の射出
成形機あるいは金型での成形が不可能となる欠点
がある。
本発明者等はこれらの欠点を解決するために
種々研究を重ねた結果比粘度0.23以下の塩素化塩
化ビニル重合体をABS樹脂にブレンドすること
によつて本発明の目的が達成できることを見出し
た。
本発明で使用する比粘度0.23以下の塩素化塩化
ビニル重合体（以下比粘度の低い塩素化塩化ビニ
ル重合体と称する）は重合度が低いために成形用
組成物として供することはできない。しかしなが
らこのような比粘度の低い塩素化塩化ビニル重合
体をABS樹脂にブレンドした場合は比粘度の高
い塩素化塩化ビニル樹脂とは異なる特異的な性質
を有することを見出した。すなわちABS樹脂に
比粘度の高い塩素化塩化ビニル樹脂をブレンドし
た場合混和性が不充分であり、且つ流動性も低
く、加えて加工時のせん断摩擦発熱によつて成形
品中に熱分解物が混入（以下やけと称する）する
が本発明のように比粘度の低い塩素化塩化ビニル
重合体を使用した場合には流動性、加工性が改良
され且つ成形時熱安定性も著しく改良され、やけ
の現象も生起しないと云う特異的な性質を有す
る。かかる現象は例えば塩素化塩化ビニル樹脂と
近似した塩化ビニル樹脂と比較すれば明らかなよ
うに比粘度の低い塩化ビニル重合体は比粘度の高
い塩化ビニル樹脂に比しその機械的強度が著しく
低く、且つ加熱時の熱安定性も低下ることを考慮
すれば比粘度の低い塩素化塩化ビニル重合体の特
異性が容易に理解されるところである。
次に代表的なABSについて述べると、ABSは
ポリブタジエンゴム、スチレン―ブタジエン共重
合体ゴム、アクリロニトリル―ブタジエン共重合
体ゴム等のゴム状物質の存在下に、スチレンとア
クリロニトリルとの単量体混合物を重合して得ら
れるいわゆるグラフト型ABSまたは前記ゴム状
物質とスチレン―アクリロトニトリル共重合体と
の混合によつて得られるブレンド型ABS、およ
び前記グラフト型ABSとブレンド型ABSとの混
合型によつて代表されるが、その他前記アクリロ
ニトリルの全部あるいはその一部をメタクリル酸
メチルで置換してその透明性を改良したものある
いは前記スチレンの全部あるいはその一部をメチ
ルスチレンで置換してその耐熱性を向上したもの
等のABS類似の樹脂組成物を含むものである。
そしてこれらABSは公知の方法によつて製造す
ることができる。これらのABSはその使用に際
し特に制限はないが、最終製品の品質を考慮する
と、クラフト型ABSが望ましい。その組成はた
とえばブタジエン成分10〜60重量％、アクリロニ
トリル成分10〜40重量％、スチレン成分20〜60重
量％の範囲のものが一般に用いられる。
この塩素化塩化ビニル重合体の製造を下記に示
す。
重合容器に水200部、重合触媒等を0.1〜１部仕
込み、適当な撹拌下に60〜70℃に保ち、10〜15時
間重合することによつて、塩化ビニル重合体を得
る。得られた塩化ビニル重合体150部と水850部を
グラスライニング槽に仕込む。内容物を充分に撹
拌しながら窒素ガスを吹込み反応系内の空気を一
旦置換する。内容物を加熱し50〜70℃に保ち酸素
を含む塩素ガスを導入して反応を開始し、60〜70
％の塩素含有量となるまで反応を継続する。
所定の塩素含有量に達したら塩素ガスの導入を
止め生成物を過し、付着している塩素および塩
酸を水洗除去し乾燥して白色の塩素化塩化ビニル
重合体の粉末を得る。
本発明における樹脂組成物はその100重量部あ
たりABS樹脂50〜90重量部および比粘度0.23以下
の塩素化塩化ビニル重合体50〜10重量部とからな
る。そしてさらに難燃性の高い組成物が希望され
る場合には難燃剤を１〜10重量部程度配合しても
よい。
その他通常このような成形用樹脂組成物に用い
られる配合剤、たとえば、熱安定剤、滑剤、加工
助剤、紫外線吸収剤、抗酸化剤、顔料、可塑剤、
改質剤等を使用することができる。
また混合手段も適宜選択することができ、たと
えばヘンシエルミキサー、スーパーミキサー、リ
ボンブレンダー、バンバリーミキサー、ミキシン
グロール等が用いられる。
次いでこれら混合物を粉末状のまま、もしくは
押出機ロール、ペレタイザー等により、ペレツト
化して押出成形機射出成形機、カレンダーロール
成形機、プレス成形機等により成形品とすること
ができる。
また少量の安定剤で熱安定性を改善できるとい
う観点からすれば重合時に抗酸化剤、熱安定剤を
使用して得られる塩化ビニル重合体を原料とする
塩素化塩化ビニルを使用することが最も好まし
い。
以下本発明を実施例、比較例により具体的に説
明する。なお実施例、比較例中「部」は重量部数
を示す。また実施例中の各種測定、試験は以下の
方法によつて行つた。
塩化ビニル樹脂および塩素化塩化ビニル重合体
の比粘度
JIS Ｋ―6721
塩素化塩化ビニル重合体塩素含有量
フラスコ燃焼法
静的熱安定性
ABS樹脂、塩素化塩化ビニル重合体所定量に
安定剤としてブチル錫マレート５部を添加しヘン
シエルミキサーにより混合し後40mm押出機にてベ
レツト化したものをロールにて160℃で10分間混
線し、0.5mm厚みのロールシートを得る。これを
５cm×10cmのたんざく状とし、200℃の熱風循環
式乾燥機中に入れた時のロールシートたんざく片
の熱分解時間でもつて測定した。
シート折曲強度
前項ロールシートを破損分離する迄繰返し交互
に折り曲げその回数で示した。
成形時熱安定性
前項ベレツトを径36mmのインラインスクリユー
式射出成形機にて、シリンダー温度が、後部170
℃、中央部180℃、前部190℃、金型温度60℃の温
度条件でスパイラルフロー流動性を測定し、かつ
厚み２mm、高さ2.0mm、縦250mm、横120mmのベン
皿を射出成形した時の成形品に表われる。ヤケの
度合を下記の基準によつて判定した。
◎…ヤケが認められない 〇…若干ヤケが認めら
れる △少しヤケが認められる ×…かなりヤケ
が認められる
流動性
前項スパイラルフロー長さによつて測定。
難燃性
US Subject 94記載の方法により1/16インチ厚
みの試料について測定した。
実施例 １〜４
重合容器に水200部、過硫酸カリウム0.4部を仕
込み容器中の空気を窒素で置換した後、塩化ビニ
ル100部フエノール系抗酸化剤0.005部およびエポ
キシ系熱安定剤0.05部を加えた。内容物を適当な
撹拌下に62℃に保ち、さらに亜硫酸ナトリウム
0.01部を添加し、連鎖移動剤3.8部15時間重合す
ることによつて直径１μ以下の球状の第一次粒子
の凝集体である塊状の塩化ビニル重合体を得る。
このものを適当に粉砕することによつて、適当な
粒度分布を有する塩化ビニル重合体粉末が得られ
る。
この粉末150部と水850部をグラスライニング槽
に仕込む。内容物を十分に撹拌しながら、窒素ガ
スを吹込み、反応系内の空気を一旦置換する。内
容物を加熱し、75℃に保ち、酸素を含む塩素ガス
を導入して反応を開始する。
反応物の塩素含有量が65％に達したら塩素ガス
の導入を止め、生成物を過し、付着している塩
素および塩酸を水洗除去し乾燥して白色比粘度
0.14塩素含有量65.2％の塩素化塩化ビニル重合体
粉末を得る。
この塩素化塩化ビニル重合体10〜50部とABS
樹脂（アクリロニトリル―ブタジエン―スチレン
組成比：20：42：38）90〜50部とからなる混合物
について前記試験法で測定した結果を表１に示
す。
比較例 １〜４
前記実施例１〜４の重合条件のうち、重合温度
を58℃としかつ連鎖移動剤、抗酸化剤、熱安定剤
を加えずに12時間重合することにより比粘度0.32
の塩化ビニル重合体を得、それを同様に塩素化し
て比粘度0.27、塩素含有量65.4の塩素化塩化ビニ
ル重合体を得た。前記ABS15〜70部とこの塩素
化塩化ビニル重合体85〜30の割合でブレンドして
所定の試験をした結果を表１に併記する。
比較例 ５および６
ABS樹脂と実施例１〜４の水溶性重合触媒を
用いた塩素化塩化ビニル樹脂との割合が、10：90
および95：５の場合の例を比較例５および６とし
て表１に示す。
実施例 ５および６
重合容器に水200部油溶性重合触媒としてジオ
クチルパーオキシジカーボネート0.05部および懸
濁剤部分ケン化ポリ酢酸ビニル0.05部を仕込み、
連鎖移動剤としてトリクロルエチレン4.8部、フ
エノール系抗酸化剤0.01部、エポキシ系熱安定剤
0.1部を加え容器内の空気を窒素で置換した後、
塩化ビニル100部を加える。内容物を適当な撹拌
下に58℃に保ち15時間重合し塩化ビニル重合体を
得る。この塩化ビニル重合体を実施例１〜４と同
様に塩素化して、比粘度0.15、塩素含有量64.2％
の塩素化塩化ビニル重合体を得た。これを用いて
ABS樹脂との混合割合を50：50および40：60と
して所定の試験をした結果を表２に記す。
比較例 ７および８
実施例５で得られた塩素化前の比粘度0.17の塩
化ビニル重合体をABSと50：50および40：60の
割合でブレンドして所定の試験をした結果を表２
に併記する。
比較例 ９〜12
実施例５の重合条件中重合温度をそれぞれ67
℃、65℃、62℃および58℃としかつ連鎖移動剤、
抗酸化剤、熱安定剤を加えずに10〜13時間重合さ
せ重合度、705，810，900，1020の塩化ビニル樹
脂を得た。この塩化ビニル樹脂と実施例１〜４と
同様に塩素化して比粘度0.25，0.27，0.29，
0.32，塩素含有量64.1，64.3，64.5，64.3％の塩
素化塩化ビニル樹脂を得ABSと50：50の割合で
ブレンドし所定の試験をした結果を表２に併記す
る。
比較例 13〜16
前記比較例９〜12で調製した比粘度0.28，
0.31，0.33，0.36塩化ビニル樹脂をABSと50：50
の割合でブレンドし所定の試験をした結果を表２
に示した。
Rubber polymers such as ABS resin have good impact resistance, heat resistance, and processability, and have no major drawbacks in other physical properties, so they are widely used in electrical equipment parts, automobile parts, furniture, building materials, etc. There is. However, recently, as safety in the event of fire has become more important in these application fields, the flammability of rubbery polymers has come to be seen as a major drawback. Conventionally, a method of blending flame retardants has been proposed as a method of imparting flame retardancy to rubber polymers, but in addition to the toxicity of the flame retardants, this method also has the fatal problem of deteriorating the physical properties of the rubber polymers. There were some shortcomings. It has also been proposed to blend a vinyl chloride resin into a rubbery polymer, but this has the drawback that the heat resistance and moldability of the rubbery polymer are significantly reduced, and the inherent properties of the rubbery polymer are significantly impaired. be. (Refer to Japanese Unexamined Patent Publication No. 11341/1983). Furthermore, attempts have been made to blend chlorinated vinyl chloride resins with rubbery polymers, but these have used chlorinated vinyl chloride resins with a high degree of polymerization.
Generally, chlorinated vinyl chloride resin is prepared by chlorinating vinyl chloride resin used for molding. That is, vinyl chloride monomer is first subjected to suspension polymerization in an aqueous medium in the presence of an oil-soluble polymerization catalyst and a dispersant to obtain a vinyl chloride resin, which is then further chlorinated to prepare a chlorinated vinyl chloride resin. . However, when chlorinated vinyl chloride resin derived from such a production method is blended with a rubbery polymer, flame retardancy can be imparted, but processability is significantly reduced, and injection molding for molding rubbery polymers is difficult. It has the disadvantage that it cannot be molded using a machine or a mold. The inventors of the present invention have conducted various studies to solve these drawbacks, and as a result, they have found that the objects of the present invention can be achieved by blending a chlorinated vinyl chloride polymer with a specific viscosity of 0.23 or less into an ABS resin. . The chlorinated vinyl chloride polymer used in the present invention with a specific viscosity of 0.23 or less (hereinafter referred to as a chlorinated vinyl chloride polymer with a low specific viscosity) cannot be used as a molding composition because of its low degree of polymerization. However, it has been found that when such a chlorinated vinyl chloride polymer with a low specific viscosity is blended with an ABS resin, it has specific properties different from that of a chlorinated vinyl chloride resin with a high specific viscosity. In other words, when ABS resin is blended with chlorinated vinyl chloride resin that has a high specific viscosity, the miscibility is insufficient and the fluidity is also low, and in addition, thermal decomposition products are generated in the molded product due to heat generated by shear friction during processing. However, when a chlorinated vinyl chloride polymer with a low specific viscosity is used as in the present invention, the fluidity and processability are improved, and the thermal stability during molding is also significantly improved. It has the unique property of not even occurring the following phenomena. This phenomenon is obvious when comparing vinyl chloride resins, which are similar to chlorinated vinyl chloride resins, for example. Vinyl chloride polymers with low specific viscosity have significantly lower mechanical strength than vinyl chloride resins with high specific viscosity. Considering that the thermal stability during heating also decreases, the uniqueness of the chlorinated vinyl chloride polymer having a low specific viscosity can be easily understood. Next, let's talk about typical ABS. ABS consists of a monomer mixture of styrene and acrylonitrile in the presence of a rubbery substance such as polybutadiene rubber, styrene-butadiene copolymer rubber, or acrylonitrile-butadiene copolymer rubber. So-called graft-type ABS obtained by polymerization, blend-type ABS obtained by mixing the above-mentioned rubbery substance and styrene-acrylotonitrile copolymer, and mixed-type ABS of the above-mentioned graft-type ABS and blend-type ABS. In addition, all or part of the acrylonitrile is replaced with methyl methacrylate to improve its transparency, or all or part of the styrene is replaced with methylstyrene to improve its heat resistance. This includes resin compositions similar to ABS, such as improved ones.
These ABS can be manufactured by known methods. Although there are no particular restrictions on the use of these ABS, craft-type ABS is preferable when considering the quality of the final product. The composition generally used is, for example, a butadiene component of 10 to 60% by weight, an acrylonitrile component of 10 to 40% by weight, and a styrene component of 20 to 60% by weight. The production of this chlorinated vinyl chloride polymer is shown below. A vinyl chloride polymer is obtained by charging 200 parts of water and 0.1 to 1 part of a polymerization catalyst into a polymerization container, maintaining the temperature at 60 to 70°C with appropriate stirring, and polymerizing for 10 to 15 hours. 150 parts of the obtained vinyl chloride polymer and 850 parts of water are charged into a glass lining tank. While thoroughly stirring the contents, nitrogen gas is blown into the reaction system to once replace the air in the reaction system. Heat the contents and keep it at 50-70℃ and introduce chlorine gas containing oxygen to start the reaction.
% chlorine content. When a predetermined chlorine content is reached, the introduction of chlorine gas is stopped, the product is filtered, the attached chlorine and hydrochloric acid are washed away with water, and the product is dried to obtain a white chlorinated vinyl chloride polymer powder. The resin composition in the present invention comprises 50 to 90 parts by weight of ABS resin and 50 to 10 parts by weight of chlorinated vinyl chloride polymer having a specific viscosity of 0.23 or less per 100 parts by weight. If a composition with even higher flame retardancy is desired, about 1 to 10 parts by weight of a flame retardant may be added. Other compounding agents normally used in such molding resin compositions, such as heat stabilizers, lubricants, processing aids, ultraviolet absorbers, antioxidants, pigments, plasticizers,
Modifiers etc. can be used. Further, the mixing means can be selected as appropriate, and for example, a Henschel mixer, a super mixer, a ribbon blender, a Banbury mixer, a mixing roll, etc. are used. Next, these mixtures can be made into powders or pelletized using an extruder roll, pelletizer, etc., and molded products can be made using an extruder injection molding machine, a calendar roll molding machine, a press molding machine, etc. Also, from the perspective of improving thermal stability with a small amount of stabilizer, it is best to use chlorinated vinyl chloride made from a vinyl chloride polymer obtained by using an antioxidant and a thermal stabilizer during polymerization. preferable. The present invention will be specifically explained below using Examples and Comparative Examples. In Examples and Comparative Examples, "parts" indicate parts by weight. Further, various measurements and tests in the examples were performed by the following methods. Specific viscosity of vinyl chloride resin and chlorinated vinyl chloride polymer JIS K-6721 Chlorine content of chlorinated vinyl chloride polymer Flask combustion method Static thermal stability ABS resin, chlorinated vinyl chloride polymer Add butyl as a stabilizer to a specified amount 5 parts of tin malate was added, mixed in a Henschel mixer, and formed into a pellet in a 40 mm extruder. The mixture was mixed with a roll at 160°C for 10 minutes to obtain a rolled sheet with a thickness of 0.5 mm. This was shaped into 5 cm x 10 cm pieces, and the thermal decomposition time of the rolled sheet pieces was measured when placed in a hot air circulation dryer at 200°C. Sheet bending strength: Indicates the number of times the rolled sheet is repeatedly and alternately bent until it breaks and separates. Thermal stability during molding The above-mentioned beret was used in an in-line screw type injection molding machine with a diameter of 36 mm, and the cylinder temperature at the rear was 170 mm.
The spiral flow fluidity was measured under the following temperature conditions: 180°C in the center, 190°C in the front, and 60°C in the mold, and a bent plate with a thickness of 2 mm, height of 2.0 mm, length of 250 mm, and width of 120 mm was injection molded. It appears in the molded products of time. The degree of discoloration was determined according to the following criteria. ◎...No discoloration 〇...Slight discoloration △Slight discoloration ×...Fluidity with considerable discoloration Measured by the spiral flow length described above. Flame Retardance Measured as described in US Subject 94 on 1/16 inch thick samples. Examples 1 to 4 200 parts of water and 0.4 parts of potassium persulfate were placed in a polymerization container, and after the air in the container was replaced with nitrogen, 100 parts of vinyl chloride, 0.005 parts of a phenolic antioxidant, and 0.05 parts of an epoxy heat stabilizer were added. added. The contents were kept at 62°C with proper stirring and further heated with sodium sulfite.
By adding 0.01 part of a chain transfer agent and polymerizing for 15 hours with 3.8 parts of a chain transfer agent, a bulk vinyl chloride polymer, which is an aggregate of spherical primary particles with a diameter of 1 μm or less, is obtained.
By appropriately pulverizing this material, a vinyl chloride polymer powder having an appropriate particle size distribution can be obtained. 150 parts of this powder and 850 parts of water are charged into a glass lined tank. While thoroughly stirring the contents, nitrogen gas is blown into the reaction system to temporarily replace the air in the reaction system. The contents are heated and maintained at 75°C, and chlorine gas containing oxygen is introduced to initiate the reaction. When the chlorine content of the reactant reaches 65%, the introduction of chlorine gas is stopped, the product is filtered, the attached chlorine and hydrochloric acid are removed by washing with water, and the product is dried to a white color with specific viscosity.
0.14 A chlorinated vinyl chloride polymer powder with a chlorine content of 65.2% is obtained. 10 to 50 parts of this chlorinated vinyl chloride polymer and ABS
Table 1 shows the results of measurements using the above test method on a mixture consisting of 90 to 50 parts of resin (acrylonitrile-butadiene-styrene composition ratio: 20:42:38). Comparative Examples 1 to 4 Among the polymerization conditions of Examples 1 to 4, the specific viscosity was 0.32 by polymerizing for 12 hours at a polymerization temperature of 58°C and without adding a chain transfer agent, antioxidant, or heat stabilizer.
A vinyl chloride polymer was obtained, which was similarly chlorinated to obtain a chlorinated vinyl chloride polymer having a specific viscosity of 0.27 and a chlorine content of 65.4. Table 1 also shows the results of predetermined tests carried out by blending 15 to 70 parts of the above ABS and 85 to 30 parts of this chlorinated vinyl chloride polymer. Comparative Examples 5 and 6 The ratio of ABS resin to chlorinated vinyl chloride resin using the water-soluble polymerization catalyst of Examples 1 to 4 was 10:90.
Examples of the ratio of 95:5 and 95:5 are shown in Table 1 as Comparative Examples 5 and 6. Examples 5 and 6 A polymerization vessel was charged with 200 parts of water, 0.05 part of dioctyl peroxydicarbonate as an oil-soluble polymerization catalyst, and 0.05 part of partially saponified polyvinyl acetate as a suspending agent.
4.8 parts of trichlorethylene as chain transfer agent, 0.01 part of phenolic antioxidant, epoxy heat stabilizer
After adding 0.1 part and replacing the air in the container with nitrogen,
Add 100 parts of vinyl chloride. The contents were polymerized for 15 hours while being kept at 58°C with appropriate stirring to obtain a vinyl chloride polymer. This vinyl chloride polymer was chlorinated in the same manner as in Examples 1 to 4, and the specific viscosity was 0.15 and the chlorine content was 64.2%.
A chlorinated vinyl chloride polymer was obtained. using this
Table 2 shows the results of predetermined tests conducted at mixing ratios of 50:50 and 40:60 with ABS resin. Comparative Examples 7 and 8 The vinyl chloride polymer with a specific viscosity of 0.17 before chlorination obtained in Example 5 was blended with ABS at a ratio of 50:50 and 40:60 and a prescribed test was conducted. The results are shown in Table 2.
Also listed in Comparative Examples 9 to 12 The polymerization temperature was set to 67% under the polymerization conditions of Example 5, respectively.
℃, 65℃, 62℃ and 58℃ and chain transfer agent,
Polymerization was carried out for 10 to 13 hours without adding an antioxidant or heat stabilizer to obtain vinyl chloride resins with polymerization degrees of 705, 810, 900, and 1020. This vinyl chloride resin was chlorinated in the same manner as in Examples 1 to 4 to give a specific viscosity of 0.25, 0.27, 0.29,
Table 2 also shows the results of predetermined tests on chlorinated vinyl chloride resins with a chlorine content of 0.32%, 64.1%, 64.3%, 64.5%, and 64.3%, blended with ABS at a ratio of 50:50. Comparative Examples 13-16 Specific viscosity 0.28 prepared in Comparative Examples 9-12 above,
0.31, 0.33, 0.36 vinyl chloride resin and ABS 50:50
Table 2 shows the results of blending at the ratio of
It was shown to.
【表】【table】
【表】
表１，２の比較より比粘度0.23以下の塩素化塩
化ビニル重合体を用いることにより、成形時熱安
定性、流動性が有意に改良されかつシート折曲げ
強度で表わされる耐衝撃性もそれほど低下してい
ないことがわかる。
また、表２の実施例５，６と比較例７，８との
比較より予期しないことに比粘度の低い塩素化塩
化ビニル重合体の方が比粘度の低い塩化ビニル重
合体より耐衝撃性すなわちシート折曲げ強度が有
意に優れていることがわかる。
これは比較例９〜12と比較例13〜16との比較よ
り一般的には例13〜16の塩化ビニル重合体を使用
した方が、例９〜12の塩素化塩化ビニル重合体を
使用した場合よりその耐衝撃性が大きい。
従来の知見によれば塩化ビニル樹脂の方が塩素
化塩化ビニル樹脂より耐衝撃性が大きいことは
ABSをブレンドしない場合すなわちこれらの単
独系でも明らかであり、一般常識となつている。
しかるに本発明に見られる如く、比粘度の低い
領域においてABSとブレンドした場合、塩化ビ
ニル重合体と塩素化塩化ビニル重合体との前記の
関係が逆転したことは実用的にも興味深い知見で
あり、従来知られていなかつた新しい知見であ
る。[Table] Comparison of Tables 1 and 2 shows that by using a chlorinated vinyl chloride polymer with a specific viscosity of 0.23 or less, the thermal stability and fluidity during molding are significantly improved, and the impact resistance expressed by sheet bending strength is improved. It can be seen that the value has not decreased that much. Further, from the comparison between Examples 5 and 6 and Comparative Examples 7 and 8 in Table 2, it was unexpectedly found that the chlorinated vinyl chloride polymer with a lower specific viscosity had better impact resistance, i.e., than the vinyl chloride polymer with a lower specific viscosity. It can be seen that the sheet bending strength is significantly superior. This shows that in general, using the vinyl chloride polymers of Examples 13-16 is better than using the chlorinated vinyl chloride polymers of Examples 9-12 than comparing Comparative Examples 9-12 and Comparative Examples 13-16. Its impact resistance is greater than the case. According to conventional knowledge, vinyl chloride resin has greater impact resistance than chlorinated vinyl chloride resin.
This is obvious even when ABS is not blended, that is, when these systems are used alone, and has become common knowledge. However, as seen in the present invention, when blended with ABS in the low specific viscosity region, the above relationship between vinyl chloride polymer and chlorinated vinyl chloride polymer was reversed, which is an interesting finding from a practical standpoint. This is new knowledge that was previously unknown.