JPH09104782A - Manufacture of polystyrene foamed particle - Google Patents
Manufacture of polystyrene foamed particleInfo
- Publication number
- JPH09104782A JPH09104782A JP8246889A JP24688996A JPH09104782A JP H09104782 A JPH09104782 A JP H09104782A JP 8246889 A JP8246889 A JP 8246889A JP 24688996 A JP24688996 A JP 24688996A JP H09104782 A JPH09104782 A JP H09104782A
- Authority
- JP
- Japan
- Prior art keywords
- particles
- rubber
- resin
- modified polystyrene
- foaming agent
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明はゴム変性ポリスチレ
ン樹脂から成る性能の改良された発泡粒子の製造方法に
関する。更に詳しくは、耐割れ性が良好で、かつ外観特
性が良く、発泡剤ガスの保持性が改良された発泡粒子の
製造方法に関する。FIELD OF THE INVENTION The present invention relates to a process for producing expanded particles of rubber-modified polystyrene resin with improved performance. More specifically, it relates to a method for producing expanded particles having good crack resistance, good appearance characteristics, and improved retention of a blowing agent gas.
【０００２】[0002]
【従来の技術】ポリスチレンから成る発泡粒子は、いろ
いろな形態に成形され、包装材、緩衝材などに広く使用
されている。しかし、そのポリスチレン発泡粒子の成形
体における割れ、欠け耐性は充分なものではなく、比較
的重量の大きな包装貨物の緩衝材として使用すると、輸
送中の衝撃で割れが発生し、衝撃が繰り返される場合に
は製品を損傷させる危惧があった。一方、衝撃による割
れを防ぐため緩衝材の厚みを大きくすると梱包体寸法が
大きくなり、輸送効率の低下を招くという問題がある。
そこで上記問題の解決策としてポリスチレンにブタジエ
ン成分を添加した樹脂の発泡粒子を作ることが提案され
ている。2. Description of the Related Art Expanded particles made of polystyrene are molded into various forms and are widely used as packaging materials, cushioning materials and the like. However, the molded polystyrene foam particles do not have sufficient resistance to cracking and chipping, and when used as a cushioning material for relatively heavy packaged cargo, cracking occurs due to shock during transportation, and repeated shocks occur. Had a fear of damaging the product. On the other hand, if the thickness of the cushioning material is increased in order to prevent cracking due to impact, the size of the package becomes large, which causes a problem of lowering transportation efficiency.
Therefore, as a solution to the above problem, it has been proposed to make expanded beads of resin by adding a butadiene component to polystyrene.
【０００３】例えば特開昭５６−６７３４４号公報には
ポリスチレン中に非配向性のゴム粒子を分散させた樹脂
から成る、耐衝撃性の改善された発泡粒子が示されてい
る。しかし、この発泡粒子はゴム粒子が非配向性である
ため、ゴム粒子の変形がおこりにくいものであった。従
って、発泡体を形成する薄い気泡膜中ではゴム粒子が気
泡膜面から露出しやすく、特に発泡倍率の高い予備発泡
粒子においてはゴム粒子の露出により発泡剤ガスの保持
性は不十分なものであった。For example, Japanese Unexamined Patent Publication No. 56-67344 discloses expanded particles having improved impact resistance, which are made of a resin in which non-oriented rubber particles are dispersed in polystyrene. However, since the foamed particles have non-oriented rubber particles, the rubber particles are less likely to be deformed. Therefore, the rubber particles are easily exposed from the surface of the foam film in the thin foam film forming the foam, and especially in the pre-expanded particles having a high expansion ratio, the retention of the foaming agent gas is insufficient due to the exposure of the rubber particles. there were.
【０００４】又、特開昭６３−１７５０４３号公報に
は、スチレン−ブタジエンブロック共重合体をスチレン
モノマー中に溶かした溶液を重合させて得た気泡サイズ
の均一なスチレン系重合体の発泡体が開示されている。
そして、特開平２−３１１５４２号公報にはスチレン可
溶性ゴムをスチレンに溶解させ重合させて得た強度の改
善されたスチレン系重合体の発泡体が開示されている。
しかし、これらの発泡体も耐割れ性の改善についてはま
だ不十分なものであった。即ち、発泡体の耐割れ性は、
発泡体の圧縮強度や引張り伸び性、気泡構造等複数の物
性因子で発現されるものであり、これらの物性は発泡体
を構成する気泡膜中のゴム粒子の分散構造に依存するも
のである。Further, JP-A-63-175043 discloses a foam of a styrene-based polymer having a uniform cell size, which is obtained by polymerizing a solution of a styrene-butadiene block copolymer dissolved in a styrene monomer. It is disclosed.
JP-A-2-311542 discloses a styrene-based polymer foam having improved strength obtained by dissolving and polymerizing styrene-soluble rubber in styrene.
However, these foams are still insufficient in improving crack resistance. That is, the crack resistance of the foam is
It is expressed by a plurality of physical factors such as compressive strength, tensile elongation and foam structure of the foam, and these physical properties depend on the dispersion structure of rubber particles in the foam film constituting the foam.
【０００５】さらに特開平３−１８２５２９号公報には
ハイインパクトポリスチレンと、水素添加したスチレン
−ブタジエンのブロック共重合体とを機械的に混合した
樹脂の発泡体が開示されている。しかし、該発泡体では
機械的に混合したゴム成分を含むため混合されたゴム成
分の分散が不十分であると、発泡体気泡膜のゴム成分分
散が不均一になり、気泡が連通化しやすい。この傾向は
特に高倍させた時には著しく、高倍発泡粒子は膨張力が
低下するため、発泡粒子成形体には粒子間空隙が見ら
れ、成形品の外観が劣るものであった。Further, Japanese Unexamined Patent Publication (Kokai) No. 3-182529 discloses a resin foam obtained by mechanically mixing a high-impact polystyrene and a hydrogenated styrene-butadiene block copolymer. However, since the foam contains a mechanically mixed rubber component, if the mixed rubber component is not sufficiently dispersed, the dispersion of the rubber component in the foam cell membrane becomes non-uniform, and the bubbles are likely to communicate. This tendency is remarkable especially when the magnification is increased, and the expansion power of the highly magnified foamed particles is reduced. Therefore, voids between particles are observed in the foamed molded article, and the appearance of the molded article is inferior.
【０００６】[0006]
【発明が解決しようとする課題】本発明はこのような従
来技術の問題を解決し、予備発泡後の発泡剤ガスの保持
性が良く、高倍発泡させたものでも独立気泡率が高い発
泡粒子であって、発泡粒子成形体とした時に耐割れ性が
優れ、外観の良い成形体となる発泡粒子の製造法を提供
することを目的とする。SUMMARY OF THE INVENTION The present invention solves the problems of the prior art as described above, and is a foamed particle which has a good retention of a foaming agent gas after pre-foaming and has a high closed cell ratio even when expanded by a high ratio. Therefore, it is an object of the present invention to provide a method for producing expanded beads, which is a molded product having excellent cracking resistance and good appearance when formed into an expanded beads molded product.
【０００７】[0007]
【課題を解決するための手段】本発明は、ゴム変性ポリ
スチレン樹脂から発泡粒子を製造する方法であって、下
記工程からなることを特徴とするポリスチレン系発泡粒
子の製造方法に係わる。 （１）ポリスチレン系樹脂の連続相とブタジエン系ゴム
粒子の分散相とから成るゴム変性ポリスチレン系樹脂で
あって、該連続相の３０℃トルエン中での極限粘度が
０．６以上０．９以下であり、該ブタジエン系ゴム粒子
の２５℃トルエン中での膨潤指数が６．５以上、１３．
５以下であるゴム変性ポリスチレン樹脂を、押出し機内
で発泡剤と加熱溶融状態で混合し、溶融混合物を得る工
程 （２）前記溶融混合物を押出機内において、５０ｋｇ／
ｃｍ2 Ｇ以上、３００ｋｇ／ｃｍ2 Ｇ以下の圧力下で、
１３０℃以上の温度に１５分以上保持し、発泡剤を含浸
させたゴム変性ポリスチレン樹脂を得る工程 （３）前記発泡剤を含浸させたゴム変性ポリスチレン樹
脂を押出した後、切断し、粒状にすることによって発泡
性粒子を得る工程 （４）前記発泡性粒子を加熱する工程The present invention relates to a method for producing expanded beads from a rubber-modified polystyrene resin, which is characterized by comprising the following steps. (1) A rubber-modified polystyrene-based resin comprising a continuous phase of polystyrene-based resin and a dispersed phase of butadiene-based rubber particles, wherein the continuous phase has an intrinsic viscosity of 0.6 or more and 0.9 or less in toluene at 30 ° C. And the swelling index of the butadiene rubber particles in toluene at 25 ° C. is 6.5 or more, 13.
A step of mixing a rubber-modified polystyrene resin of 5 or less with a foaming agent in a heating and melting state in an extruder to obtain a molten mixture. (2) The molten mixture in an extruder is 50 kg /
Under a pressure of not less than cm 2 G and not more than 300 kg / cm 2 G,
Step of obtaining a rubber-modified polystyrene resin impregnated with a foaming agent by holding at a temperature of 130 ° C. or higher for 15 minutes or more (3) Extruding the rubber-modified polystyrene resin impregnated with the foaming agent, and then cutting it into granules To obtain expandable particles (4) Step of heating the expandable particles
【０００８】以下、本発明を図面を用いて詳述する。図
１は本発明における発泡粒子の気泡膜を厚み方向の断面
で見た時の断面を示す模式説明図である。６は発泡粒
子、５はゴム粒子のブタジエン系成分部、４はゴム粒子
のポリスチレン系成分部、３はポリスチレン系連続相、
１は気泡膜断面、２は気泡膜面を示している。ａは該ゴ
ム粒子の気泡膜厚み方向の寸法、ｂは該ゴム粒子の気泡
膜面方向の寸法であり、各々最も大きな部分の寸法であ
る。Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic explanatory view showing a cross section when a cell membrane of expanded particles in the present invention is viewed in a cross section in a thickness direction. 6 is a foamed particle, 5 is a butadiene component of rubber particles, 4 is a polystyrene component of rubber particles, 3 is a polystyrene continuous phase,
Numeral 1 indicates a cross section of the cell membrane, and numeral 2 indicates a cell membrane surface. a is the size of the rubber particles in the thickness direction of the bubble film, and b is the size of the rubber particles in the direction of the bubble film surface, each being the size of the largest part.
【０００９】図２、図３は気泡膜の模式説明図である。
即ち、気泡膜断面（１）は気泡膜（９）の厚み方向の断
面であり、気泡膜（９）は発泡粒子断面（７）の気泡
（８）を形づくるものである。図３は図２の破線部分の
拡大図である。FIGS. 2 and 3 are schematic illustrations of a bubble film.
That is, the cell membrane section (1) is a section in the thickness direction of the cell membrane (9), and the cell membrane (9) forms a bubble (8) of the foam particle section (7). FIG. 3 is an enlarged view of a broken line portion in FIG.
【００１０】ゴム変性ポリスチレン系樹脂の耐割れ性能
は樹脂が衝撃を受けた時にマトリックス相に発生する割
れの伝播をゴム相が抑えることで発現する。従って、ゴ
ム変性ポリスチレン系樹脂から成る発泡粒子成形体の耐
割れ性においても、成形体が衝撃を受けた時に発生する
割れの伝播を、その気泡膜中に存在するゴム粒子が抑え
ることで発現すると考えられる。しかし、樹脂と発泡体
気泡膜とでは樹脂連続相中に分散しているゴム粒子の形
状、ゴム粒子の配向状態、樹脂の配向状態等が全く異な
っており、樹脂と気泡膜とでは耐割れ性に適したゴム相
分散構造は異なるものである。[0010] The crack resistance of the rubber-modified polystyrene resin is exhibited by the rubber phase suppressing the propagation of cracks generated in the matrix phase when the resin is impacted. Therefore, even in the crack resistance of the foamed particle molded article made of the rubber-modified polystyrene resin, the propagation of cracks generated when the molded article is subjected to an impact is expressed by suppressing the rubber particles present in the foam film. Conceivable. However, the shape of the rubber particles dispersed in the resin continuous phase, the orientation state of the rubber particles, the orientation state of the resin, and the like are completely different between the resin and the foam cell membrane. The rubber phase dispersion structure suitable for is different.
【００１１】本発明はポリスチレン系樹脂の連続相に、
ポリスチレン系樹脂が小粒子状に内包されたブタジエン
系重合体ゴム粒子が分散したゴム変性ポリスチレン系樹
脂から成る発泡粒子の気泡膜中でのゴム粒子の分散構造
を特定することで、耐割れ性に優れ、発泡剤ガスの保持
性にも優れ、高倍発泡させても独立気泡率が高く、成形
体外観のよい発泡粒子が得られることを示すものであ
る。The present invention relates to a continuous phase of a polystyrene resin,
By specifying the dispersion structure of rubber particles in the foam film of foamed particles composed of rubber-modified polystyrene resin in which butadiene polymer rubber particles in which polystyrene resin is encapsulated in small particles, crack resistance is improved. It shows that foamed particles having excellent foaming agent gas retention properties, a high closed cell ratio even when foamed at a high magnification, and a good appearance of a molded article can be obtained.
【００１２】本発明においては、気泡膜断面におけるゴ
ム粒子の偏平状態を示すアスペクト比（ｂ／ａ）はラン
ダムに選んだ２０個のゴム粒子のアスペクト比の平均値
として算出し、その値は１０以上７０以下が好ましい。
また、更に好ましくは１０以上４０以下である。（ｂ／
ａ）が１０未満であると気泡膜面からゴム粒子が露出し
やすくなり、発泡剤ガスの保持性が低下する。また、
（ｂ／ａ）が７０を越えると粒子が偏平になりすぎゴム
相が薄くなって亀裂の伝播を抑えにくくなり、発泡体の
耐割れ性が低下する。In the present invention, the aspect ratio (b / a) showing the flat state of the rubber particles in the cross section of the bubble film is calculated as the average value of the aspect ratios of 20 randomly selected rubber particles, and the value is 10. It is preferably 70 or more and 70 or less.
Further, it is more preferably 10 or more and 40 or less. (B /
When a) is less than 10, the rubber particles are likely to be exposed from the surface of the cell membrane, and the retention of the blowing agent gas is reduced. Also,
When (b / a) exceeds 70, the particles become too flat and the rubber phase becomes thin so that it is difficult to suppress the propagation of cracks and the crack resistance of the foam decreases.
【００１３】本発明においては、（ａ／ｃ）は気泡膜厚
みと、ランダムに選んだ２０個のゴム粒子の（ａ／ｃ）
値の平均値として算出し、０．０１以上０．２以下が好
ましい。また、更に好ましくは０．０１以上０．１以下
である。（ａ／ｃ）が０．０１未満であるとゴム相が膜
厚みに比べ小さくなり、亀裂の伝播を抑えにくくなり、
発泡体の耐割れ性が低下する。また、（ａ／ｃ）が０．
２を越えると気泡膜面からゴム粒子が露出しやすくな
り、発泡剤ガスの保持性が低下する。気泡膜断面の気泡
膜厚みは好ましくは０．２μｍ以上１０μｍ以下であ
り、更に好ましくは０．３μｍ以上５μｍ以下である。In the present invention, (a / c) is the thickness of the bubble film and (a / c) of 20 randomly selected rubber particles.
It is calculated as an average value, and is preferably 0.01 or more and 0.2 or less. Further, it is more preferably 0.01 or more and 0.1 or less. If (a / c) is less than 0.01, the rubber phase becomes smaller than the film thickness, making it difficult to suppress crack propagation,
The crack resistance of the foam decreases. In addition, (a / c) is equal to 0.
If it exceeds 2, rubber particles are likely to be exposed from the surface of the cell membrane, and the retention of the blowing agent gas is reduced. The thickness of the bubble film in the cross section of the bubble film is preferably 0.2 μm or more and 10 μm or less, and more preferably 0.3 μm or more and 5 μm or less.
【００１４】本発明においては、気泡膜を厚み方向の断
面で見た時に、ゴム粒子が厚み方向に複数、層状に存在
する。層の数は好ましくは、厚み方向に２以上２０以下
であり、更に好ましくは、２以上１０以下である。気泡
膜を厚み方向の断面で見た時に、ゴム粒子が厚み方向に
複数存在しないものでは亀裂の伝播を抑えにくく割れ易
い。In the present invention, when the bubble film is viewed in a cross section in the thickness direction, a plurality of rubber particles are present in a layer shape in the thickness direction. The number of layers is preferably 2 or more and 20 or less in the thickness direction, and more preferably 2 or more and 10 or less. When the bubble film is viewed in a cross section in the thickness direction, it is difficult to suppress the propagation of cracks and easily cracked if there are no plural rubber particles in the thickness direction.
【００１５】本発明においては、気泡膜を厚み方向の断
面で見たときに、気泡膜厚みを一辺とする正方形内に、
少なくともゴム粒子の一部が存在する、ゴム粒子の数が
２個以上、７０個以下存在することが好ましい。更に好
ましくは、５個以上５０個以下である。ａ、ｂ、ｃの値
は、以下のようにして測定できる。すなわち、発泡粒子
の切出断面を有する発泡粒子を用意し、２％四酸化オス
ミウム水溶液に２４時間浸漬、蒸留水にて洗浄した後、
常温硬化タイプのエポキシ樹脂に包埋、ウルトラミクロ
ト−ムを用いて超薄切片を作成し、この切片を電子顕微
鏡観察することで、ａ、ｂ、ｃの値を明瞭に測定でき
る。In the present invention, when the bubble film is viewed in a cross section in the thickness direction, a square having the bubble film thickness on one side is defined as:
It is preferable that at least a part of the rubber particles exist, and that the number of the rubber particles be 2 or more and 70 or less. More preferably, the number is 5 or more and 50 or less. The values of a, b, and c can be measured as follows. That is, foamed particles having a cut-out cross section of foamed particles are prepared, immersed in a 2% osmium tetroxide aqueous solution for 24 hours, washed with distilled water,
The values of a, b, and c can be clearly measured by embedding in a room temperature curing type epoxy resin, creating an ultrathin section using an ultramicrotome, and observing the section with an electron microscope.
【００１６】気泡膜断面のゴム粒子の形状は、特に限定
されるものではなく、例えば、円、楕円、不定形なども
とりうる。また、本発明において、発泡粒子の形状は特
に限定されるものではなく、例えば、球状、楕円球状、
円柱状などがある。The shape of the rubber particles in the cross section of the cell membrane is not particularly limited, and may be, for example, a circle, an ellipse, or an irregular shape. In the present invention, the shape of the expanded particles is not particularly limited, for example, spherical, oval spherical,
There is a columnar shape.
【００１７】本発明においては発泡粒子の見掛け密度は
０．０１２ｇ／ｃｍ3 以上０．１ｇ／ｃｍ3 以下が好ま
しい。また、更に好ましい範囲は０．０１４ｇ／ｃｍ3
以上０．０７以下である。見掛け密度が０．０１２ｇ／
ｃｍ3 未満であると、発泡粒子の独立気泡率が低下する
上、発泡粒子成形体の強度が低下する。また、見掛け密
度が０．１ｇ／ｃｍ3 を越えると成形体を包装材、緩衝
材として使用するには重量的に大きくなり、経済的に不
利である。In the present invention, the apparent density of the expanded particles is preferably 0.012 g / cm 3 or more and 0.1 g / cm 3 or less. A more preferable range is 0.014 g / cm 3.
It is above 0.07. Apparent density 0.012g /
When it is less than 3 cm 3 , the closed cell ratio of the expanded beads decreases and the strength of the expanded particle molded article decreases. Further, if the apparent density exceeds 0.1 g / cm 3 , it is economically disadvantageous because the molded body becomes large in weight when used as a packaging material or a cushioning material.
【００１８】本発明において気泡膜断面のゴム粒子が特
定の偏平状となるのは、樹脂が発泡する過程即ち、気泡
の膨張に伴って、気泡膜が延伸される過程において、連
続相であるポリスチレン系樹脂の延びに伴って、分散相
のゴム粒子が適度に延伸されることを意味している。こ
れは連続相ポリスチレン系樹脂と分散相ゴム粒子の発泡
過程における両者の粘弾性の組み合わせを特定すること
で達成される。ゴム成分の粘弾性はゴム成分の架橋度、
ゴム成分の分子量等により異なる。また、連続相である
ポリスチレン系樹脂の粘弾性は樹脂の分子量等により異
なる。本発明においては、該ゴム変性ポリスチレン系樹
脂の連続相の極限粘度が０．６以上０．９以下であり、
該ゴム変性ポリスチレン系樹脂の架橋ゴム成分の膨潤指
数が６．５以上、１３．５以下であることが好ましい。
ここで言う極限粘度とは換算粘度ｖｓ濃度（ｇ／ｄｌ）
曲線を濃度ゼロに外挿した時の粘度であり、膨潤指数と
は２５℃トルエン溶媒中での膨潤指数である。In the present invention, the rubber particles in the cross section of the cell membrane have a specific flat shape because polystyrene which is a continuous phase is formed in the process of foaming the resin, that is, in the process of expanding the cell membrane as the bubbles expand. This means that the rubber particles of the dispersed phase are appropriately stretched with the extension of the system resin. This is achieved by specifying the combination of the viscoelasticity of the continuous phase polystyrene resin and the dispersed phase rubber particles in the foaming process. The viscoelasticity of the rubber component is the degree of crosslinking of the rubber component,
It depends on the molecular weight of the rubber component. Further, the viscoelasticity of the polystyrene resin as the continuous phase varies depending on the molecular weight of the resin. In the present invention, the intrinsic viscosity of the continuous phase of the rubber-modified polystyrene resin is 0.6 or more and 0.9 or less,
The cross-linked rubber component of the rubber-modified polystyrene resin preferably has a swelling index of 6.5 or more and 13.5 or less.
Here, the intrinsic viscosity is the converted viscosity vs. concentration (g / dl).
This is the viscosity when the curve is extrapolated to zero concentration, and the swelling index is the swelling index in a 25 ° C toluene solvent.
【００１９】連続相の極限粘度が０．６未満では連続相
の分子量が小さく、流動性が大きくなり、樹脂の強度も
低下する。また、連続相の極限粘度が０．９を越えるも
のはゴム変性ポリスチレン系樹脂として製造が難しい。
連続相の極限粘度として特に好ましい範囲は０．６５以
上、０．８５以下である。When the intrinsic viscosity of the continuous phase is less than 0.6, the molecular weight of the continuous phase is small, the flowability is increased, and the strength of the resin is reduced. If the intrinsic viscosity of the continuous phase exceeds 0.9, it is difficult to produce a rubber-modified polystyrene resin.
A particularly preferred range for the intrinsic viscosity of the continuous phase is 0.65 or more and 0.85 or less.
【００２０】架橋ゴム成分の膨潤指数が６．５未満であ
ると架橋の度合いが高すぎ、発泡の過程でゴム粒子が偏
平になりにくい。また、膨潤指数が１３．５を越えると
架橋度合いが小さく、ゴムとしての伸びが不足し、耐割
れ性の発現が劣る。架橋ゴム成分の膨潤指数として特に
好ましい範囲は８．５以上１２．５以下である。When the swelling index of the crosslinked rubber component is less than 6.5, the degree of crosslinking is too high, and the rubber particles are less likely to become flat during the foaming process. On the other hand, when the swelling index exceeds 13.5, the degree of crosslinking is small, the elongation as rubber is insufficient, and the development of crack resistance is inferior. A particularly preferred range for the swelling index of the crosslinked rubber component is 8.5 or more and 12.5 or less.
【００２１】本発明において、ゴム相の架橋は以下のよ
うにおこる。即ち、ゴムを溶解させたスチレンモノマ−
溶液を重合し、重合終了後、未反応モノマ−や溶媒の回
収のため、減圧下で温度を高温（１５０℃以上）にした
時にゴムの架橋がおこる。In the present invention, the crosslinking of the rubber phase occurs as follows. That is, styrene monomer in which rubber is dissolved
The solution is polymerized, and after completion of the polymerization, rubber is crosslinked when the temperature is raised to a high temperature (150 ° C. or higher) under reduced pressure in order to recover unreacted monomers and solvents.
【００２２】本発明のゴム変性ポリスチレン系樹脂はポ
リスチレン系樹脂中にゴム粒子を分散させたものであ
る。ゴム粒子をポリスチレン系樹脂中に分散させる方法
には、（１）スチレン系モノマーにブタジエン系ゴム成
分を溶解させた溶液を重合させ、ポリスチレン系樹脂の
連続相中にゴム粒子を分散相として存在させる方法と
（２）ポリスチレン系樹脂にブタジエン系ゴム成分を機
械的に混合する方法がある。The rubber-modified polystyrene resin of the present invention is obtained by dispersing rubber particles in a polystyrene resin. The method of dispersing rubber particles in a polystyrene resin is as follows: (1) A solution in which a butadiene rubber component is dissolved in a styrene monomer is polymerized, and the rubber particles are present as a dispersed phase in a continuous phase of the polystyrene resin. And (2) a method of mechanically mixing a butadiene rubber component with a polystyrene resin.
【００２３】（１）の方法はゴム成分を独立したゴム粒
子として分散でき、好ましい。（２）の方法ではゴム成
分を機械的に混合するため、ゴム成分が不定形になり、
微分散させにくく、また、分散が不均一になりやすい。The method (1) is preferable because the rubber component can be dispersed as independent rubber particles. In the method (2), since the rubber component is mechanically mixed, the rubber component becomes indefinite,
It is difficult to finely disperse, and the dispersion tends to be uneven.
【００２４】また、（１）の方法で得られるゴム粒子を
独立したゴム粒子として分散させたゴム変性ポリスチレ
ン系樹脂とブタジエン系ゴム成分とを（２）の方法のよ
うに機械的に混合して、ゴム変性ポリスチレン系樹脂を
得る方法もある。この場合、機械的に混合するブタジエ
ン系ゴム成分は、（１）の方法で得た独立したゴム粒子
成分量を少なくすることが好ましい。また、この時には
用いるブタジエン系ゴム成分としては、スチレン−ブタ
ジエン共重合体が好ましく、更にはスチレン−ブタジエ
ンブロック共重合体が好ましい。また、混合するブタジ
エン系ゴム成分は本発明の効果を損なわない程度に混合
することが好ましい。例えば、（１）の方法で得られた
ゴム変性ポリスチレン系樹脂重量９０に対し、ブタジエ
ン系ゴム成分の重量は１０以下にすることが好ましい。Also, a rubber-modified polystyrene resin in which the rubber particles obtained by the method (1) are dispersed as independent rubber particles and a butadiene rubber component are mechanically mixed as in the method (2). There is also a method of obtaining a rubber-modified polystyrene resin. In this case, the butadiene rubber component to be mechanically mixed is preferably reduced in the amount of the independent rubber particle component obtained by the method (1). In this case, the butadiene rubber component used is preferably a styrene-butadiene copolymer, and more preferably a styrene-butadiene block copolymer. The butadiene rubber component to be mixed is preferably mixed to such an extent that the effects of the present invention are not impaired. For example, the weight of the butadiene-based rubber component is preferably 10 or less based on the weight of the rubber-modified polystyrene-based resin obtained by the method (1) of 90.
【００２５】（１）の方法で得られるゴム粒子の構造に
は、ゴム成分を外殻とする粒子内部に単数のポリスチ
レン系粒子が内包された、いわゆるコアシェル構造と
ブタジエン系成分を外殻とする粒子内部に複数のポリス
チレン系粒子が内包された、いわゆるサラミ構造があ
る。The structure of the rubber particles obtained by the method (1) has a so-called core-shell structure in which a single polystyrene-based particle is encapsulated inside a particle having a rubber component as an outer shell, and a butadiene-based component as an outer shell. There is a so-called salami structure in which a plurality of polystyrene-based particles are included inside the particles.
【００２６】本発明のブタジエン系ゴム粒子はコアシェ
ル構造のもの、サラミ構造のもの、あるいは両者の混合
物を用いることができる。これらのゴム構造の中では、
粒径が０．１μｍ以上、１μｍ以下より好ましくは０．
１μｍ以上、０．５μｍ以下のコアシェル構造のもの、
及び、粒径が１μｍ以下のコアシェル構造のもの８０ｗ
ｔ％以上とサラミ構造のもの２０ｗｔ％以下の混合物が
特に好ましい。粒径が１μｍ以下のコアシェル構造のゴ
ム粒子は発泡体気泡膜中でゴム成分を均一に分散させる
ことができる。特に発泡倍率が高い発泡粒子では気泡膜
厚みが小さくなるため、粒径の小さいゴム粒子は均一分
散に好適である。この場合、ゴム粒子の粒径は０．１μ
ｍ以上、１．０μｍ以下、より好ましくは０．１μｍ以
上、０．５μｍ以下である。一方、ゴム粒子がポリスチ
レン系樹脂分を複数内包するサラミ構造ではゴム粒子径
が１μｍ以上と比較的大きくなり、気泡膜内でのゴム成
分の均一な分散を行いにくい。The butadiene rubber particles of the present invention may have a core-shell structure, a salami structure, or a mixture of both. Within these rubber structures,
The particle size is 0.1 μm or more and 1 μm or less, more preferably 0.1 μm or less.
Having a core-shell structure of 1 μm or more and 0.5 μm or less,
And 80 w having a core-shell structure having a particle size of 1 μm or less.
A mixture of t% or more and 20 wt% or less having a salami structure is particularly preferred. Rubber particles having a core-shell structure having a particle diameter of 1 μm or less can uniformly disperse the rubber component in the foam cell membrane. Particularly, in the case of expanded particles having a high expansion ratio, the thickness of the cell membrane is small, so that rubber particles having a small particle diameter are suitable for uniform dispersion. In this case, the particle size of the rubber particles is 0.1 μm.
m or more and 1.0 μm or less, more preferably 0.1 μm or more and 0.5 μm or less. On the other hand, in a salami structure in which rubber particles include a plurality of polystyrene-based resins, the rubber particle diameter is relatively large at 1 μm or more, and it is difficult to uniformly disperse the rubber component in the bubble film.
【００２７】本発明において、発泡前のゴム変性ポリス
チレン中のゴム粒子の形状は、特に限定されるものでは
なく、例えば、球状、楕円球状、あるいは不定形状のも
のがとりうる。In the present invention, the shape of the rubber particles in the rubber-modified polystyrene before foaming is not particularly limited, and may be, for example, spherical, elliptical, or irregular.
【００２８】本発明においては、発泡粒子の重量は特に
限定されないが、好ましくは発泡粒子一粒当たりの平均
重量が０．２ｍｇ〜２ｍｇ、好ましくは０．４ｍｇ〜
１．２ｍｇである。ここで、発泡粒子一粒当たりの平均
重量とは、ランダムに選んだ２００粒の発泡粒子の平均
値をいう。In the present invention, the weight of the expanded particles is not particularly limited, but preferably the average weight per expanded particle is 0.2 mg to 2 mg, preferably 0.4 mg to 2 mg.
1.2 mg. Here, the average weight per expanded particle refers to the average value of 200 randomly selected expanded particles.
【００２９】次に、本発明のポリスチレン系発泡粒子の
製造方法について説明する。本発明のゴム変性ポリスチ
レンから発泡粒子を得る方法で好ましい方法は、以下の
工程から成る製造方法である。Next, the method for producing expanded polystyrene particles according to the present invention will be described. A preferred method for obtaining expanded particles from the rubber-modified polystyrene of the present invention is a production method comprising the following steps.
【００３０】（１） ポリスチレン系樹脂の連続相とブ
タジエン系ゴム粒子の分散相とからなるゴム変性ポリス
チレン系樹脂であって、連続相の極限粘度が０．６ｄｌ
／ｇ以上、０．９ｄｌ／ｇ以下であり、ゴム分の膨潤指
数が６．５以上、１３．５以下であるゴム変性ポリスチ
レン系樹脂を押出機内で発泡剤を加熱溶融状態で混合す
る工程。(1) A rubber-modified polystyrene resin comprising a continuous phase of a polystyrene resin and a dispersed phase of butadiene rubber particles, wherein the intrinsic viscosity of the continuous phase is 0.6 dl.
/ G or more and 0.9 dl / g or less, and a rubber-modified polystyrene resin having a rubber swelling index of 6.5 or more and 13.5 or less is mixed in an extruder by heating and melting a foaming agent.
【００３１】（２） 溶融混合物を押出機内において、
５０ｋｇ／ｃｍ2 Ｇ以上、３００ｋｇ／ｃｍ2 Ｇ以下の
圧力下で、１３０℃以上の温度下に１５分以上保持する
工程。 （３） 発泡剤を含浸したゴム変性ポリスチレンを押出
機から押出した後、切断し、粒状にする工程 。 （４） 得られた発泡性粒子を加熱する工程。(2) The molten mixture is placed in an extruder
A step of maintaining the pressure of not less than 50 kg / cm 2 G and not more than 300 kg / cm 2 G at a temperature of not less than 130 ° C. for not less than 15 minutes. (3) A step of extruding a rubber-modified polystyrene impregnated with a foaming agent from an extruder, cutting and granulating the modified polystyrene. (4) A step of heating the obtained expandable particles.
【００３２】本発明で用いるゴム変性ポリスチレン系樹
脂は塊状重合あるいは塊状懸濁併用重合、照射重合等の
通常の方法により製造できる。塊状重合は一般に次の様
に実施される。まず、ブタジエン系重合体をスチレン系
モノマーに溶解し、この溶液を加熱撹拌しつつ重合させ
る。The rubber-modified polystyrene resin used in the present invention can be produced by a conventional method such as bulk polymerization, bulk suspension combined polymerization, irradiation polymerization and the like. Bulk polymerization is generally carried out as follows. First, a butadiene-based polymer is dissolved in a styrene-based monomer, and this solution is polymerized while being heated and stirred.
【００３３】ブタジエン系重合体としてはポリブタジエ
ン（ローシスポリブタジエン及びハイシスポリブタジエ
ン：ここでロ−シスポリブタジエンにはシス１−４付加
３５％、トランス１−４付加５２％、１−２付加１３％
を含む。またハイシスポリブタジエンにはシス１−４付
加９０〜９８％、トランス１−４付加１〜４％、１−２
付加１〜６％を含む）、スチレン−ブタジエン共重合体
（ランダム及びブロックＳＢＲ）、ポリイソプレン、ブ
タジエン−イソプレン共重合体等であるが、中でもポリ
ブタジエン、スチレン−ブタジエン共重合体が好まし
い。これらは単独で用いてもよいし、また、２種以上の
混合物として用いてもよい。Examples of the butadiene-based polymer include polybutadiene (low-cis polybutadiene and high-cis polybutadiene: where cis 1-4 addition is 35%, trans 1-4 addition 52%, and 1-2 addition 13% is low-cis polybutadiene.
including. Also, cis 1-4 addition 90-98%, trans 1-4 addition 1-4%, high cis polybutadiene 1-2
Styrene-butadiene copolymer (including random and block SBR), polyisoprene, butadiene-isoprene copolymer, etc., of which polybutadiene and styrene-butadiene copolymer are preferred. These may be used alone or as a mixture of two or more.
【００３４】また、スチレン系モノマーは、スチレンの
外、ｏ−メチルスチレン、ｐ−メチルスチレン、ｍ−メ
チルスチレン、２，４−ジメチルスチレン、エチルメチ
ルスチレン、等の核アルキル置換スチレン、α−メチル
スチレン等のα−アルキル置換スチレン、ｏ−クロルス
チレン等の核ハロゲン化スチレンであり、単独またはい
ずれか２種以上の混合物として用いられる。The styrene-based monomers include styrene, nucleus alkyl-substituted styrenes such as o-methylstyrene, p-methylstyrene, m-methylstyrene, 2,4-dimethylstyrene, ethylmethylstyrene, and α-methyl. Α-alkyl-substituted styrene such as styrene, and nuclear halogenated styrene such as o-chlorostyrene; used alone or as a mixture of two or more of them.
【００３５】本発明において、連続相を形成するポリス
チレン系樹脂としては単一モノマ−によるホモポリマ−
のほか、スチレン系モノマ−成分が５０ｗｔ％以上を含
有するスチレン系共重合ポリマ−も用いることができ
る。共重合モノマ−としては、例えばアクリロニトリ
ル、メチルメタクリレ−ト、無水マレイン酸などがあ
る。In the present invention, the polystyrene resin forming the continuous phase is a homopolymer of a single monomer.
In addition, a styrene copolymer containing 50% by weight or more of a styrene monomer component can be used. Examples of the copolymerized monomer include acrylonitrile, methyl methacrylate, and maleic anhydride.
【００３６】重合反応時には、溶媒を加えることも出
来、その溶剤は芳香族炭化水素類、例えばトルエン、キ
シレン、エチルベンゼンの単独または２種以上の混合物
が使用できる。前記重合液は１００〜１８０℃の温度で
重合しうるが、品質を高めるために重合開始剤が使用さ
れる。At the time of the polymerization reaction, a solvent may be added, and the solvent may be an aromatic hydrocarbon such as toluene, xylene or ethylbenzene, or a mixture of two or more thereof. The polymerization solution can be polymerized at a temperature of 100 to 180 ° C, and a polymerization initiator is used to improve the quality.
【００３７】使用できる重合開始剤として１，１−ビス
（ｔ−ブチルパーオキシ）シクロヘキサン等のパーオキ
シケタール類、ジ−ｔ−ブチルパーオキサイド等のジア
ルキルパーオキサイド類、ベンゾイルパーオキサイド等
のジアルパーオキサイド類、その他パーオキシジカーボ
ネート類、パーオキシエステル類、ケトンパーオキサイ
ド類、ハイドロパーオキサイド類がある。As polymerization initiators that can be used, peroxyketals such as 1,1-bis (t-butylperoxy) cyclohexane, dialkyl peroxides such as di-t-butyl peroxide, and dialrups such as benzoyl peroxide. There are oxides, other peroxydicarbonates, peroxyesters, ketone peroxides, and hydroperoxides.
【００３８】また、連鎖移動剤としては、例えばα−メ
チルスチレンダイマー、ｎ−ドデシルメルカプタン、ｔ
−ドデシルメルカプタン、１−フェニルブテン−２−フ
ルオレン、ジペンテン、クロロホルム等のメルカプタン
類、テルペン類、ハロゲン化合物等を用いることができ
る。As the chain transfer agent, for example, α-methylstyrene dimer, n-dodecyl mercaptan, t
-Mercaptans such as dodecyl mercaptan, 1-phenylbutene-2-fluorene, dipentene and chloroform, terpenes, halogen compounds and the like can be used.
【００３９】重合反応は、温度５０〜１７０℃、好まし
くは９０〜１５５℃の範囲で、一定温度あるいは２以上
の段階的に漸次昇温（この時の昇温速度は０．２〜２℃
／分、より好ましくは０．４〜１．５℃／分である。）
して行い、所定の転化率まで重合を進めた後、未反応モ
ノマーや溶剤を加熱下での減圧処理等により除去し、ゴ
ム変性ポリスチレン系樹脂を得る。The polymerization reaction is carried out at a temperature of 50 to 170 ° C., preferably 90 to 155 ° C., at a constant temperature or gradually in two or more steps (at a rate of 0.2 to 2 ° C.).
/ Min, more preferably 0.4 to 1.5 ° C / min. )
After the polymerization is advanced to a predetermined conversion rate, unreacted monomers and solvent are removed by a reduced pressure treatment under heating or the like to obtain a rubber-modified polystyrene resin.
【００４０】この樹脂を連続的に押出し機に供給し、押
出し機内で加熱溶融しながら押出機のダイに設けられた
細孔より糸状に押出し、直ちに水を貯えた冷却バスで冷
却しつつ上下２本の駆動ロールで挟み、引き取りながら
回転式カッターで長さ方向にカットし樹脂粒子を得る。This resin is continuously supplied to an extruder, extruded into a thread form through a pore provided in a die of the extruder while being heated and melted in the extruder, and immediately cooled while being cooled by a cooling bath containing water. The resin particles are cut in the length direction by a rotary cutter while being sandwiched between book drive rolls and taken off.
【００４１】分散ゴム粒子をコアシェル型とするために
は、重合時に、例えばスチレン−ブタジエンブロック共
重合体を用いることが好ましい。スチレン系モノマ−に
スチレン−ブタジエンブロック共重合体を溶解させた溶
液を重合するとき、スチレンブロックはマトリックスの
スチレン系ポリマ−相と親和性が良いため、互いに集ま
り、またブタジエンブロックはブタジエンブロック同士
で集まり、コア型を形成すると考えられる。In order to make the dispersed rubber particles core-shell type, it is preferable to use, for example, a styrene-butadiene block copolymer at the time of polymerization. When a solution in which a styrene-butadiene block copolymer is dissolved in a styrene-based monomer is polymerized, the styrene blocks have a good affinity for the styrene-based polymer phase of the matrix, so they are gathered together, and the butadiene block is formed of butadiene blocks. It is believed that they come together to form a core mold.
【００４２】分散ゴム粒子をコアシェル型とするために
用いるスチレン−ブタジエンブロック共重合体のブタジ
エン成分は２０〜８０％が好ましい。分散ゴム粒子をコ
アシェル構造とするためには、用いるブタジエン系重合
体のポリスチレン系樹脂に対する親和性を高める、重合
液の粘度を調整する、撹はんの速度と時間を調整する、
均質な撹はん装置を用いる等多くの製造条件の選定によ
って達成される（例えば特開昭６０−１３０６１３号公
報に示される）。The butadiene component of the styrene-butadiene block copolymer used to make the dispersed rubber particles a core-shell type is preferably 20 to 80%. In order to make the dispersed rubber particles have a core-shell structure, the affinity of the butadiene-based polymer used for the polystyrene-based resin is increased, the viscosity of the polymerization solution is adjusted, the stirring speed and time are adjusted,
This can be achieved by selecting a number of production conditions such as using a homogeneous stirring device (for example, as shown in JP-A-60-130613).
【００４３】また、一方、分散ゴム粒子をサラミ型とす
るためには、重合時に、例えばポリブタジエンを用いる
ことが好ましい。スチレン系モノマ−にポリブタジエン
を溶解させた溶液を重合する時、分散ゴム粒子内部にス
チレン系ポリマ−が入り込み、サラミ型を形成すると考
えられる。On the other hand, in order to make the dispersed rubber particles salami-type, it is preferable to use, for example, polybutadiene during polymerization. It is considered that when a solution in which polybutadiene is dissolved in a styrene monomer is polymerized, the styrene polymer enters the inside of the dispersed rubber particles to form a salami type.
【００４４】また、塊状懸濁併用重合も用いることがで
きる。この方法ではまず前半での反応を塊状で行い、後
半の反応を懸濁状態で行うものである。即ち、この方法
はブタジエン系重合体をスチレン系モノマーに溶解させ
た後、前記塊状重合と同じように重合させモノマーの１
０ないし４０％を部分的に重合させた後、この部分的に
重合した混合物を懸濁安定剤、界面活性剤の存在下に水
性媒体中に撹拌下に分散させ、反応の後半を懸濁重合で
完結させ、洗浄、乾燥し必要によりペレットまたは粉末
化させるものである。また、得られた樹脂に必要に応じ
て、染顔料、滑剤、充填剤、離型剤、可塑剤、帯電防止
剤、発泡核剤、紫外線安定剤等の添加剤を加えることが
できる。In addition, bulk suspension combined polymerization can also be used. In this method, the reaction in the first half is first performed in a lump, and the reaction in the second half is performed in a suspended state. That is, in this method, a butadiene-based polymer is dissolved in a styrene-based monomer, and then polymerized in the same manner as in the bulk polymerization described above.
After partially polymerizing 0 to 40%, the partially polymerized mixture is dispersed under stirring in an aqueous medium in the presence of a suspension stabilizer and a surfactant, and the latter half of the reaction is subjected to suspension polymerization. And then washed, dried, and pelletized or powdered as necessary. If necessary, additives such as dyes and pigments, lubricants, fillers, release agents, plasticizers, antistatic agents, foam nucleating agents, and ultraviolet stabilizers can be added to the obtained resin.
【００４５】本発明において、発泡性樹脂粒子、発泡粒
子、及びその成形体を得る方法は次のとおりである。ま
ず、前記で得られたゴム変性ポリスチレン樹脂に発泡剤
を含浸させ、発泡性粒子を得る方法としては、押出し含
浸法または懸濁含浸法を用いることができる。In the present invention, the method for obtaining the expandable resin particles, the expandable particles, and the molded product thereof is as follows. First, as a method for impregnating the rubber-modified polystyrene resin obtained above with a foaming agent to obtain foamable particles, an extrusion impregnation method or a suspension impregnation method can be used.
【００４６】押出し含浸法においては、前記で得られた
ゴム変性ポリスチレン系樹脂粒子を押出機内で加熱溶融
した後、別途押出機に通じる発泡剤供給ラインを通して
揮発性発泡剤を圧入して、溶融状態にある樹脂と十分混
合し、更に１３０℃以上の溶融状態で１５分以上、好ま
しくは２０分以上滞留させた後、押出機のダイに設けら
れた細孔より糸状に押出し、直ちに水を貯えた冷却バス
で冷却しつつ上下２本の駆動ロールで挟み、引き取りな
がら回転式カッターで長さ方向にカットし発泡性樹脂粒
子を得る。In the extrusion impregnation method, the rubber-modified polystyrene-based resin particles obtained above are heated and melted in an extruder, and then a volatile foaming agent is press-fitted through a foaming agent supply line that is separately connected to the extruder to form a molten state. After the mixture was sufficiently mixed with the resin in the above section and further kept in a molten state at 130 ° C. or more for 15 minutes or more, preferably for 20 minutes or more, it was extruded into a thread form from pores provided in a die of an extruder, and water was immediately stored. While being cooled by a cooling bath, it is sandwiched between two upper and lower drive rolls, and is cut in a length direction by a rotary cutter while being taken to obtain foamable resin particles.
【００４７】また、水中押出しカット法を用いる事がで
きる。水中押出しカット法ではカット後の粒子形状が球
形になり好ましい。また、１３０℃以上の溶融状態にお
ける押出機内の圧力は好ましくは５０〜３００ｋｇ／ｃ
ｍ2 Ｇ、より好ましくは１００〜２００ｋｇ／ｃｍ2 Ｇ
である。圧力が３００ｋｇ／ｃｍ2 Ｇを超えると、押出
機がコスト高になる。また、３００ｋｇ／ｃｍ2 Ｇ以下
では押出速度が小さくなり、生産性がよくない。Also, an underwater extrusion cutting method can be used. The underwater extrusion cutting method is preferable because the particle shape after the cutting is spherical. Further, the pressure in the extruder in a molten state of 130 ° C. or more is preferably 50 to 300 kg / c.
m 2 G, more preferably 100 to 200 kg / cm 2 G
It is. If the pressure exceeds 300 kg / cm 2 G, the cost of the extruder increases. On the other hand, when the pressure is 300 kg / cm 2 G or less, the extrusion speed becomes low, and the productivity is not good.
【００４８】押出し機内で樹脂と発泡剤とを１３０℃以
上の混合溶融状態で、の圧力下で１５分以上滞留させる
ことは発泡過程におけるゴム粒子とポリスチレン系樹脂
の粘弾性のバランスをとるための方法として有効であ
る。その理由は必ずしも明かではないが、発泡剤がゴム
成分あるいはポリスチレン系樹脂部に十分均一に含浸
し、ゴム成分が適度に可塑化されるためと考えられる。
溶融状態での滞留時間を延長するには押出機とダイとの
間に導管を設け導管の長さにより調整することができ
る。或いは押出量の調整によっても滞留時間を調整する
ことができる。The resin and the foaming agent are mixed and melted in an extruder at 130 ° C. or more under a pressure of 15 minutes or more to balance the viscoelasticity of the rubber particles and the polystyrene resin in the foaming process. It is effective as a method. Although the reason is not clear, it is considered that the foaming agent impregnates the rubber component or the polystyrene-based resin portion sufficiently uniformly, and the rubber component is appropriately plasticized.
To extend the residence time in the molten state, a conduit may be provided between the extruder and the die, and the length of the conduit may be adjusted. Alternatively, the residence time can be adjusted by adjusting the extrusion amount.
【００４９】また、懸濁含浸法においては、前記で得ら
れたゴム変性ポリスチレン系樹脂粒子を懸濁安定剤、界
面活性剤の存在下に水性媒体中に撹拌下に分散させ、発
泡剤を含浸させるものである。この方法でも含浸温度と
時間を充分に長くすることが大切である。In the suspension impregnation method, the rubber-modified polystyrene resin particles obtained above are dispersed in an aqueous medium with stirring in the presence of a suspension stabilizer and a surfactant, and impregnated with a foaming agent. It is to let. In this method, it is important that the impregnation temperature and time are sufficiently long.
【００５０】本発明で用いられる揮発性発泡剤として
は、常圧における沸点が−３０〜＋１００℃の範囲にあ
るもの、例えばプロパン、ブタン、ペンタン、ヘキサ
ン、ヘプタン、石油エーテル等の脂肪族炭化水素及びシ
クロペンタン、ジシクロクロルヘキサン等の環状脂肪族
炭化水素、及び塩化メチル、塩化エチル、臭化メチル、
ジクロロジフルオロメタン、１，２−ジクロロテトラフ
ルオロエタン、モノクロロトリフルオロエタン等のハロ
ゲン化炭化水素類等を挙げることができる。The volatile blowing agent used in the present invention has a boiling point in the range of −30 to + 100 ° C. under normal pressure, for example, aliphatic hydrocarbon such as propane, butane, pentane, hexane, heptane, petroleum ether and the like. And cycloaliphatic hydrocarbons such as cyclopentane and dicyclochlorohexane, and methyl chloride, ethyl chloride, methyl bromide,
Examples thereof include halogenated hydrocarbons such as dichlorodifluoromethane, 1,2-dichlorotetrafluoroethane, and monochlorotrifluoroethane.
【００５１】発泡前の発泡性樹脂粒子における、発泡剤
の含浸量は、０．３ｇｍｏｌ〜１．７ｇｍｏｌの発泡剤
を１００ｇのゴム変性ポリスチレン樹脂に含浸させるも
のが好ましい、０．６ｇｍｏｌ〜１．５ｇｍｏｌを１０
０ｇのゴム変性ポリスチレン樹脂に含浸させるものが更
に好ましくい。The impregnating amount of the foaming agent in the foamable resin particles before foaming is preferably such that 0.3 gmol to 1.7 gmol of the foaming agent is impregnated into 100 g of the rubber-modified polystyrene resin, and 0.6 gmol to 1.5 gmol. 10
It is more preferable to impregnate 0 g of the rubber-modified polystyrene resin.
【００５２】次にこの発泡剤の含浸された発泡性樹脂粒
子を公知のポリスチレン発泡ビーズ用発泡機でスチーム
によって発泡させ、発泡粒子とする。発泡条件は加熱温
度を９５〜１０４℃とし、この温度での発泡保持時間を
１０〜１５０秒、好ましくは２０〜６０秒とする。Next, the foamable resin particles impregnated with the foaming agent are foamed with steam using a known foaming machine for polystyrene foam beads to obtain foamed particles. As for the foaming conditions, the heating temperature is 95 to 104 ° C., and the foam holding time at this temperature is 10 to 150 seconds, preferably 20 to 60 seconds.
【００５３】発泡剤含浸樹脂粒子を温水中でアニール処
理した後発泡させ、発泡粒子の気泡の大きさを均一化さ
せることもできる。このようにして得た発泡樹脂粒子
を、これも公知のポリスチレン発泡ビーズ用自動成形機
に内蔵された成形型内で融着一体化させ、発泡成形体を
得ることができる。The resin particles impregnated with the foaming agent may be annealed in warm water and then foamed to make the size of the bubbles of the foamed particles uniform. The foamed resin particles thus obtained are fused and integrated in a mold incorporated in a known automatic molding machine for polystyrene foam beads to obtain a foam molded article.
【００５４】[0054]
【発明の実施の形態】以下に実施例により本発明の実施
の形態を説明するが、本発明はこれら実施例に限定され
るものではない。なお、実施例、比較例中の樹脂、発泡
粒子及び発泡粒子成形体の性質は以下のようにして測定
した。BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to examples, but the present invention is not limited to these examples. In addition, the properties of the resin, the foamed particles, and the foamed molded articles in Examples and Comparative Examples were measured as follows.
【００５５】（１）発泡粒子の見掛け密度 約５ｇの発泡粒子を小数以下２位でひょう量する。次
に、最小目盛単位が１ｃｍ3 である２００ｃｍ3 ガラス
製メスシリンダーに５０〜１００ｃｍ3 の水を入れ、こ
れにメスシリンダーの口径よりやや小さい円形の金網板
であって、その中心部に長さが１５〜３０ｃｍの針金が
直立して固定された発泡粒子の押圧具を没し、その時の
水位Ｈ1 ｃｍ3 を読み取る。次に押圧具を除き、ひょう
量した上記発泡粒子をメスシリンダー内に入れ押圧具で
完全に水没させた状態で水位Ｈ2 ｃｍ3 を読み取り、下
記の式により発泡粒子の見掛け密度ρ（ｇ／cm3 ）を求
めた。 ρ＝Ｗ／（Ｈ2 −Ｈ1 ） ただし、Ｗ ：発泡粒子の重量（ｇ） Ｈ1 ：発泡粒子を入れる前の水位（ｃｍ3 ） Ｈ2 ：発泡粒子を水没した後の水位（ｃｍ3 ）。(1) Foamed particles having an apparent density of about 5 g are weighed at the second decimal place. Then, minimum scale unit containing water of 50 to 100 cm 3 within 200 cm 3 glass measuring cylinder is 1 cm 3, which in a slightly smaller circular metal mesh plate than the diameter of the graduated cylinder, the length at the center thereof There died a pusher expanded beads wire of 15~30cm is fixed upright, reads the water level H1 cm 3 at that time. Then except pusher, in a state of completely submerged in pressing tool placed weighing the above expanded beads in a graduated cylinder reads the water level H2 cm 3, an apparent density ρ (g / cm of foamed particles according to the following formula 3 ) asked. ρ = W / (H2 -H1) However, W: weight of the expanded particles (g) H1: before the water level to put the foamed particles (cm 3) H2: water levels after the submerged foamed particles (cm 3).
【００５６】（２）発泡粒子成形体のかさ密度 ＪＩＳ Ｋ６７６７に準拠して以下の式により発泡粒子
成形体のかさ密度Ｄ（ｇ／ｃｍ3 ）を求めた。 Ｄ＝Ｇ／Ｖ ただし、Ｇ ：発泡粒子成形体の重量（ｇ） Ｖ ：発泡粒子成形体の体積（ｃｍ3 ） Ｖは成形体の一部を直方体に切出し、直方体のタテ、ヨ
コ、高さ寸法を測定し、「タテ」×「ヨコ」×「高さ」
により算出したものである。測定用具、及び精度はＪＩ
Ｓ Ｋ６７６７による。(2) Bulk Density of Expanded Particle Molded Product Based on JIS K6767, the bulk density D (g / cm 3 ) of the expanded particle molded product was determined by the following formula. D = G / V Where, G: weight of the expanded-particle molded product (g) V: volume of the expanded-particle molded product (cm 3 ) V is a rectangular parallelepiped cut from a part of the molded product, and the vertical, horizontal, and height of the rectangular parallelepiped Measure the dimensions and measure "vertical" x "horizontal" x "height"
It is calculated by: Measurement tools and accuracy are JI
According to SK6767.
【００５７】（３）独立気泡率 見掛け密度（ｇ／ｃｍ3 ）が既知の発泡粒子である発泡
体約２４ｃｍ3 の真の容積を東芝・ベックマン株式会社
製空気比較式比重計９３０形を用いて測定し、次式より
独立気泡率〔Ｓ，（％）〕を算出する（ＡＳＴＭ Ｄ−
２８５６）。 Ｓ＝（Ｖｘ−Ｗ／ρ）×１００／（Ｖａ−Ｗ／ρ） （％） Ｖｘ：発泡体を構成する基材樹脂の容積と、発泡体内の
独立気泡部分の気泡全容積との和（ｃｍ3 ） Ｖａ：発泡体を構成する基材樹脂の容積と、発泡体内の
独立気泡部分と連通気泡部分の気泡全容積との和（ｃｍ
3 ） Ｗ：発泡体内の発泡剤ガスを空気と十分置換させ、発泡
剤ガスの含量が０．５ｗｔ％以下になった発泡体の重量
（ｇ） ρ：発泡体の基材樹脂の密度（ｇ／ｃｍ3 ） 記 号 評価尺度 ◎ 独立気泡率９０％以上 ○ ８５％以上９０％未満 △ ８０％以上８５％未満 × ８０％未満(3) Closed cell ratio The true volume of about 24 cm 3 of a foam, which is a foamed particle having a known apparent density (g / cm 3 ), is measured using an air comparison hydrometer 930 manufactured by Toshiba Beckman Co., Ltd. Measure and calculate the closed cell rate [S, (%)] from the following equation (ASTM D-
2856). S = (Vx−W / ρ) × 100 / (Va−W / ρ) (%) Vx: The sum of the volume of the base resin constituting the foam and the total volume of cells in the closed cell portion in the foam ( cm 3 ) Va: Sum of the volume of the base resin constituting the foam and the total volume of the cells in the closed cells and the communicating cells in the foam (cm)
3 ) W: The weight of the foam in which the content of the foaming agent gas is 0.5 wt% or less by fully replacing the foaming agent gas in the foam with air (g) ρ: The density of the base resin of the foam (g / Cm 3 ) Symbol evaluation scale ◎ Closed cell ratio 90% or more ○ 85% or more and less than 90% △ 80% or more and less than 85% × less than 80%
【００５８】（４）ゴム粒子の平均粒子径および粒子径
分布 重合工程で得られたゴム変性ポリスチレン系樹脂の超薄
切片を四酸化オスミウム染色し、電子顕微鏡で撮影した
写真中のゴム粒子５００個の粒子径を測定し、次式によ
り算出する。 Ｄ：平均粒子径 Ｄ＝Σｎi ・Ｄi ／ｎi Ｒ：粒子径分布 Ｄ１＝Σｎi ・Ｄi ／ｎi Ｄ２＝Σｎi ・（Ｄi ）4 ／ｎi ・（Ｄi ）3 Ｒ ＝Ｄ２／Ｄ１ ここで、Ｄi は０．１μｍ単位（小数２位以下を四捨五
入）で測った粒径の値である。また、ｎi は粒径がＤi
となる粒子の個数である。また、ゴム粒子の断面形状が
円形でない、不定形の場合の粒径の求め方は、まず断面
形状の最大径Ｌ１を求め、次にＬ１の中心点を通る断面
径の最小径Ｌ２を求め、（Ｌ１＋Ｌ２）／２をゴム粒子
の粒径とする。(4) Average Particle Size and Particle Size Distribution of Rubber Particles Ultrathin sections of the rubber-modified polystyrene resin obtained in the polymerization step were stained with osmium tetroxide and 500 rubber particles in a photograph taken with an electron microscope Is measured and calculated by the following equation. D: Average particle diameter D = Σni · Di / ni R: Particle diameter distribution D1 = Σni · Di / ni D2 = Σni · (Di) 4 / ni · (Di) 3 R = D2 / D1 Here, Di is 0 It is the value of the particle size measured in units of 1 μm (rounding down to the first decimal place). Also, ni has a particle diameter of Di.
Is the number of particles. In addition, when the cross-sectional shape of the rubber particles is not circular or irregular, the particle size is determined by first obtaining the maximum diameter L1 of the cross-sectional shape, then obtaining the minimum diameter L2 of the cross-sectional diameter passing through the center point of L1. Let (L1 + L2) / 2 be the particle size of the rubber particles.
【００５９】（５）ゴム変性ポリスチレンの極限粘度値 ゴム変性ポリスチレン発泡粒子１ｇにメチルエチルケト
ン１８ｍｌとメタノ−ル２ｍｌの混合溶媒を加え、２５
℃で２時間振とうし、５℃、１８０００ｒｐｍで３０分
間遠心分離する。上澄み液を取り出し、メタノ−ルで樹
脂分を析出させた後、乾燥した。(5) Intrinsic Viscosity Value of Rubber-Modified Polystyrene A mixed solvent of 18 ml of methyl ethyl ketone and 2 ml of methanol was added to 1 g of the expanded rubber-modified polystyrene particles.
Shake at 2 ° C. for 2 hours and centrifuge at 18000 rpm for 30 minutes at 5 ° C. The supernatant was taken out, and the resin component was precipitated with methanol and then dried.
【００６０】このようにして得られた樹脂０．１ｇをト
ルエンに溶解し、濃度０．５ｇ／ｄｌの溶液とし、この
溶液１０ｍｌをキャノン−フェンスケ型粘度計に入れ、
３０℃で、この溶液流下秒数ｔ1 を測定した。一方、別
に同じ粘度計で純トルエンの流下秒数ｔ0 を測定し、以
下の数式により換算粘度ηsp／ｃを算出した（ポリマ−
濃度０．５ｇ／ｄｌの換算粘度）。 ηsp／ｃ＝（ｔ1 −ｔ0 ）／（ｔ0 ・ｃ） ただし、ｃはポリマ−濃度（ｇ／ｄｌ）である。次に、
ｃが１．０ｇ／ｄｌ、１．５ｇ／ｄｌの時の換算粘度を
同じようにして求める。更に、換算粘度ｖｓポリマ−濃
度の関係式をポリマ−濃度ゼロに外挿した時の粘度であ
る極限粘度〔η〕を求める。0.1 g of the resin thus obtained was dissolved in toluene to form a solution having a concentration of 0.5 g / dl, and 10 ml of this solution was placed in a Cannon-Fenske viscometer.
At 30 ° C., the number of seconds t 1 under which the solution was flowing was measured. On the other hand, the falling time t 0 of pure toluene was measured separately using the same viscometer, and the reduced viscosity η sp / c was calculated by the following equation (polymer
(Conversion viscosity at a concentration of 0.5 g / dl). η sp / c = (t 1 −t 0 ) / (t 0 · c) where c is the polymer concentration (g / dl). next,
The converted viscosities when c is 1.0 g / dl and 1.5 g / dl are similarly determined. Further, the intrinsic viscosity [η], which is the viscosity when extrapolating the relational expression of reduced viscosity vs. polymer concentration to zero polymer concentration, is determined.
【００６１】（６）ゴム変性ポリスチレンの膨潤指数 ゴム変性ポリスチレン発泡体約０．５ｇにトルエン３０
ｍｌを加え、２５℃で２４時間浸漬後、５時間振とう
し、５℃、１８，０００ｒｐｍで１時間遠心分離する。
上澄み液をデカンテーションして除いた後、新たにトル
エン３０ｍｌを加え、２５℃で１時間振とうし、５℃、
１８，０００ｒｐｍで１時間遠心分離する。上澄み液を
除き、重量をひょう量する（Ｗ1 ）。その後、１００
℃、２時間真空乾燥し、残留物の重量をひょう量する
（Ｗ2 ）。(6) Swelling Index of Rubber-Modified Polystyrene About 0.5 g of rubber-modified polystyrene foam was added with 30 parts of toluene.
After immersion at 25 ° C for 24 hours, shake for 5 hours, and centrifuge at 18,000 rpm for 1 hour at 5 ° C.
After removing the supernatant liquid by decantation, 30 ml of fresh toluene was added, and the mixture was shaken at 25 ° C for 1 hour,
Centrifuge at 18,000 rpm for 1 hour. The supernatant is removed and the weight is weighed (W1). Then 100
The residue was weighed (W2).
【００６２】次式により膨潤指数ＳＷＩを算出する。 ＳＷＩ＝（Ｗ1 −Ｗ2 ）／Ｗ2The swelling index SWI is calculated by the following formula. SWI = (W1-W2) / W2
【００６３】（７）発泡剤保持性能 発泡性粒子を発泡機にて発泡させ、見掛け密度０．０３
３ｇ／ｃｍ3 の発泡粒子とした後、該発泡粒子を２３℃
の乾燥した容器内におよそ２４時間放置し、発泡粒子表
面及び内部の湿分を除いた後取り出し、直ちに発泡剤含
有量の測定法によって発泡剤含有量を確かめた。発泡剤
含有量の測定法は以下の通りである。約５ｇの発泡粒子
を０．０１ｇ単位の精度で重量を測る。その発泡粒子を
容積が１０００ｃｍ3 であるガラスフラスコに入れる。
更に、発泡粒子の入ったガラスフラスコの重量を０．０
１ｇ単位で測定する。そして、１８０℃で６０ｍｍＨｇ
（絶対圧）下で、６０分減圧脱気する。そして、脱気さ
れたガラスフラスコを取出し、室温に冷却し、大気圧下
に戻した後、重量を測定する。発泡剤含有量は次の式で
求められる。(7) Foaming agent holding performance The expandable particles were foamed with a foaming machine, and the apparent density was 0.03.
After forming the expanded particles of 3 g / cm 3, the expanded particles were cooled to 23 ° C.
Was left in a dry container for about 24 hours, and after removing the moisture on the surface and inside of the foamed particles, the foamed particles were taken out and immediately checked for the foaming agent content by a method for measuring the foaming agent content. The measuring method of the foaming agent content is as follows. About 5 g of expanded particles are weighed to the nearest 0.01 g. The expanded particles are placed in a glass flask having a volume of 1000 cm 3 .
Furthermore, the weight of the glass flask containing the foamed particles was reduced to 0.0
Measure in 1g increments. And at 180 ° C, 60 mmHg
Degas under reduced pressure under (absolute pressure) for 60 minutes. Then, the degassed glass flask is taken out, cooled to room temperature, returned to atmospheric pressure, and then weighed. The blowing agent content is determined by the following equation.
【００６４】 Ｇ＝１００×（Ｇ1 −Ｇ2 ）／（Ｇ1 −Ｇ0 ） ここで、Ｇ0 はガラスフラスコの重さ、Ｇ1 は減圧脱気
前の発泡粒子とガラスフラスコの合計重量、Ｇ2 は減圧
脱気後の発泡粒子とガラスフラスコの合計重量である。G = 100 × (G 1 −G 2 ) / (G 1 −G 0 ) where G 0 is the weight of the glass flask, and G 1 is the total weight of the foamed particles and the glass flask before degassing under reduced pressure. , G 2 is the total weight of the expanded beads and glass flask after vacuum degassing.
【００６５】さらに３時間毎に同様の方法で発泡剤含有
量を確認し、発泡剤含有量が４（ｇ／１００ｇ樹脂）か
ら２（ｇ／１００ｇ樹脂）まで半減する時の所要時間を
確認し、以下の様に発泡剤保持性能を求めた。見掛け密
度が０. ０１８、０．０２３、０．０４０ｇ／ｃｍ3 の
発泡粒子についても同様に評価した。 記 号 所要時間（時間） ◎ １００以上 ○ ７５以上１００未満 △ ６０以上 ７５未満 × ６０未満。Further, the foaming agent content was confirmed every three hours by the same method, and the time required for the foaming agent content to be reduced by half from 4 (g / 100 g resin) to 2 (g / 100 g resin) was confirmed. The foaming agent holding performance was determined as follows. The foamed particles having an apparent density of 0.018, 0.023, and 0.040 g / cm 3 were similarly evaluated. Symbol Required time (hours) ◎ 100 or more ○ ○ 75 or more and less than 100 △ 60 or more and less than 75 × less than 60.
【００６６】（８）成形体外観 成形体表面２５ｃｍ2 当たりに観察される粒子間間隙数
であって、粒子サイズの１／２以上の空隙数を測定し、
その値により、以下の尺度で評価する。 記 号 表面の空隙数 備 考 ◎ ０〜２ 成形体外観が非常に良好 ○ ３〜５ 成形体外観がほぼ良好 △ ６〜１０ 成形体外観がやや不良 × １１〜 成形体外観が不良(8) Appearance of Molded Article The number of interparticle gaps observed per 25 cm 2 of the molded article surface was measured, and the number of voids having a size equal to or more than １ ／ of the particle size was measured.
The value is evaluated according to the following scale. Symbol Number of voids on the surface Remark ◎ 0 to 2 Very good appearance of molded product ○ 3 to 5 Almost good appearance of molded product 6 to 10 Somewhat poor appearance of molded product × 11 to 11 Bad appearance of molded product
【００６７】（９）実用緩衝落下試験 ＪＩＳ−Ｚ−０２０２に準じ、包装貨物の落下試験を行
う。図４に示すように、被包装体（１４）を４つのゴム
変性ポリスチレン樹脂発泡体のパッド即ち、パッド（１
０）、パッド（１１）、パッド（１２）、パッド（１
３）で緩衝包装する。発泡体のかさ密度が０．０３３ｇ
／ｃｍ3 、０．０１８、０．０２３、０．０４０ｇ／ｃ
ｍ3 の時は、被包装体の重量は各々３０ｋｇ、１０ｋ
ｇ、２０ｋｇ、３５ｋｇとした。パッドは被包装体が前
後左右上下の六つのパッド面から受ける静的応力が各々
０．０８〜０．１２ｋｇ／ｃｍ3 となるように形状設計
されたものを用いる。更に緩衝包装された被包装体をそ
のまま段ボール箱（１７）に収納する。(9) Practical Buffer Drop Test A drop test of packaged cargo is performed according to JIS-Z-0202. As shown in FIG. 4, the package (14) is made of four rubber-modified polystyrene resin foam pads, that is, pads (1).
0), pad (11), pad (12), pad (1
3. Buffer packaging in 3). The bulk density of the foam is 0.033g
/ Cm 3 , 0.018, 0.023, 0.040 g / c
At m 3 , the weight of the packaged object is 30 kg and 10 k, respectively.
g, 20 kg, 35 kg. As the pad, one whose shape is designed so that the static stress applied to the packaged object from the front, rear, left, right, and upper six pad surfaces is 0.08 to 0.12 kg / cm 3 is used. Further, the package-packaged object is stored in the cardboard box (17) as it is.
【００６８】包装体の落下は、まず段ボール箱の角（１
５）を下方に向けた落下を行う。この場合にはパッド
（１０）が最も大きな荷重を受ける。次に段ボール箱の
３稜（１６）を下方に向けた落下を各々１回ずつ行い、
更に段ボール箱の６面の各々を下方に向けた落下を各々
１回ずつ行った後、段ボール箱を開け４つのパッドの損
傷状態を観察する。First, the falling of the package is performed at the corner (1) of the cardboard box.
5) Drop downward. In this case, the pad (10) receives the largest load. Next, the cardboard box is dropped once with the three ridges (16) facing downward, once each.
Further, after dropping each of the six surfaces of the cardboard box downward, each time, the cardboard box is opened and the four pads are observed for damage.
【００６９】パッドの損傷状態をａ：全く割れ無し、
ｂ：局部の小クラック、ｃ：成形体厚みの半分程度の中
クラック、ｄ：大クラック、ｅ：バラバラ状態、の区分
で評価する。The damage state of the pad was a: no crack,
b: Local small cracks, c: Medium cracks of about half the thickness of the molded body, d: Large cracks, e: Disassembled.
【００７０】更に、６面落下後における４つのパッドの
損傷状態により以下の評価尺度で求めた。 記 号 評価尺度 ◎ ４つパッドがすべてａまたはｂまたはｃで、かつａまたはｂが２つ 以上ある。 ○ 上記以外であり、４つがａまたはｂまたはｃ △ 上記２項以外であり、４つの中にｄがありｅはない。 × 上記３項以外の全て。Further, the following evaluation scale was obtained based on the damage state of the four pads after falling on six surfaces. Symbol Rating scale ◎ All four pads are a or b or c, and there are two or more a or b. ○ Other than the above, four are a or b or c △ Other than the above two, d is in four, and e is not. × All except the above 3 items.
【００７１】[0071]
実施例１ （ゴム変性ポリスチレン樹脂の調製）ブタジエン成分が
６０ｗｔ％であるスチレン−ブタジエンブロック共重合
体をスチレンモノマーに溶解させ１２ｗｔ％溶液とし
た。この溶解した溶液１００重量部にエチルベンゼン５
重量部、１，１−ビス（ｔ−ブチルパーオキシ）シクロ
ヘキサン０．０５重量部及びｔ−ドデシルメルカプタン
０．０５重量部を添加し重合原料液を調製する。重合原
料液を重合器に送り重合を行った。Example 1 (Preparation of rubber-modified polystyrene resin) A styrene-butadiene block copolymer having a butadiene component of 60 wt% was dissolved in a styrene monomer to prepare a 12 wt% solution. Ethylbenzene 5 was added to 100 parts by weight of this dissolved solution.
By weight, 1,1-bis (t-butylperoxy) cyclohexane (0.05 parts by weight) and t-dodecylmercaptan (0.05 parts by weight) are added to prepare a polymerization raw material liquid. The polymerization raw material liquid was sent to a polymerization vessel to perform polymerization.
【００７２】重合温度を１０５℃で３時間、温度を上げ
１３０℃で２時間、更に温度を上げ１４５℃で１時間重
合させた後、得られた重合液を加熱真空下の脱揮装置に
送り未反応スチレンモノマー及びエチルベンゼンを除去
して、重合体を得た。得られた重合体を押出し機に供給
し、ダイの細孔からストランドを引き、直ちに水冷した
後ペレット状に切断した。得られた樹脂をＨＩＰＳ−１
とした。ＨＩＰＳ−１のブタジエン成分の含有量をスチ
レン−ブタジエンブロック共重合体、スチレンのマスバ
ランスから算出したところ、９ｗｔ％であった。The polymerization temperature was raised to 105 ° C. for 3 hours, the temperature was raised to 130 ° C. for 2 hours, and the temperature was raised to 145 ° C. for 1 hour to carry out polymerization, and the obtained polymerization solution was sent to a devolatilizer under heating vacuum. Unreacted styrene monomer and ethylbenzene were removed to obtain a polymer. The obtained polymer was supplied to an extruder, a strand was drawn from the pores of a die, immediately cooled with water, and then cut into pellets. The obtained resin was HIPS-1
And When the content of the butadiene component of HIPS-1 was calculated from the mass balance of the styrene-butadiene block copolymer and styrene, it was 9 wt%.
【００７３】ＨＩＰＳ−１をポリスチレン樹脂と混合し
た後３０ｍｍφ単軸押し出し機中で溶融混合させた。得
られた樹脂をＨＩＰＳ−２とした。ＨＩＰＳ−２のブタ
ジエン成分の含有量を測定したところ７ｗｔ％であっ
た。またスチレン−ブタジエンブロック共重合体のスチ
レンモノマ−溶液濃度を１４．５％とした外は、ＨＩＰ
Ｓ−１と同様の重合を行い、ＨＩＰＳ−３を得た。ＨＩ
ＰＳ−３のブタジエン成分量は１０．５％であった。Ｈ
ＩＰＳ−１、２、３中に分散しているゴム粒子はコアシ
ェル型で、いずれも平均粒径は０．２μｍであった。ま
た、各々の連続相樹脂の極限粘度値（以下［η］で表
す）、架橋ゴム成分の膨潤指数（以下ＳＷＩで表す）等
は表１に示す通りであった。更に、表２に後記の比較例
で用いた樹脂についても示す。HIPS-1 was mixed with polystyrene resin and then melt-mixed in a 30 mmφ uniaxial extruder. The obtained resin was designated as HIPS-2. When the content of the butadiene component of HIPS-2 was measured, it was 7 wt%. Except that the styrene monomer solution concentration of the styrene-butadiene block copolymer was set to 14.5%, HIP was used.
The same polymerization as in S-1 was performed to obtain HIPS-3. HI
The butadiene component amount of PS-3 was 10.5%. H
The rubber particles dispersed in IPS-1, 2, and 3 were of a core-shell type, and all had an average particle size of 0.2 μm. Further, the intrinsic viscosity value (hereinafter represented by [η]) of each continuous phase resin, the swelling index of the crosslinked rubber component (hereinafter represented by SWI) and the like are as shown in Table 1. Table 2 also shows the resins used in the comparative examples described below.
【００７４】（発泡性粒子の調製）上記ＨＩＰＳ−１を
発泡剤の加圧供給装置を持ち、かつその加圧供給装置か
らの接続ラインが押出機のシリンダー内の溶融混練部に
通じるように連結され、さらに前頭部に樹脂の冷却装置
と多数の流出孔（直径０．７ｍｍ）を持つダイ装置を備
えた押出含浸装置に供給し、押出機内で溶融させつつ、
発泡剤の加圧供給装置からイソペンタンを樹脂１００ｇ
量について０．１３ｇモル量比率にポンプで一定量ずつ
加圧供給し、樹脂と混練混合し、更に１３０℃の溶融状
態に２０分滞留させた後、冷却装置で適温に冷却しダイ
装置に設けられた多数の細孔より６０℃の水中に押出し
つつ回転式カッターでカットし、発泡性樹脂粒子を得
た。得られた粒子の平均粒径は１．１ｍｍであった。Ｈ
ＩＰＳ−２、３についても同様にして発泡性樹脂粒子を
得た。(Preparation of expandable particles) The above HIPS-1 has a pressure-supplying device for a foaming agent, and the connecting line from the pressure-supplying device is connected so as to communicate with the melt-kneading section in the cylinder of the extruder. Further, the resin is supplied to an extrusion impregnation device equipped with a resin cooling device and a die device having a large number of outflow holes (diameter 0.7 mm) in the forehead, while melting in the extruder,
Isopentane resin 100g from the blowing agent pressure supply device
Regarding the amount, 0.13 g molar ratio was supplied by a constant amount by a pump, kneading and mixing with the resin, and further retained in a molten state at 130 ° C. for 20 minutes, then cooled to an appropriate temperature by a cooling device and provided in a die device. While being extruded into water at 60 ° C. from the resulting large number of pores, the product was cut with a rotary cutter to obtain expandable resin particles. The average particle size of the obtained particles was 1.1 mm. H
Expandable resin particles were similarly obtained for IPS-2 and 3.
【００７５】（予備発泡及び型内成形）得られた発泡性
樹脂粒子をスチーム発泡機で発泡させた。発泡させるた
めのスチ−ムの加熱条件は次の通りである。まず、発泡
機内をスチ−ムで予熱した後、発泡性粒子を仕込み、ス
チ−ムを導入した。２０秒かけて発泡機内のエア−を、
オリフィスを設けたパ−ジ用配管から追い出しつつ、ス
チ−ムを機内に満たし、機内温度を１０２℃とした（ゲ
−ジ圧：０．１ｋｇ／ｃｍ2 Ｇ）。更に、１０２℃に１
７秒間保持した後、スチ−ムをパ−ジした。(Pre-expansion and in-mold molding) The expandable resin particles obtained were expanded by a steam expansion machine. The heating conditions of the steam for foaming are as follows. First, after the inside of the foaming machine was preheated with steam, foamable particles were charged and the steam was introduced. Air in the foaming machine for 20 seconds
The steam was filled in the machine while being expelled from the page pipe for which an orifice was provided, and the machine temperature was set to 102 ° C. (gauge pressure: 0.1 kg / cm 2 G). 1 at 102 ° C
After holding for 7 seconds, the steam was purged.
【００７６】発泡機から回収した発泡粒子を２０℃の室
内で２４時間熟成した。得られた発泡粒子は見掛け密度
が０．０３３ｇ／ｃｍ3 であった。ＨＩＰＳ−１、ＨＩ
ＰＳ−２、ＨＩＰＳ−３粒子の１粒当たりの平均重量
は、各々０．７０ｍｇ、０．６８ｍｇ、０．６９ｍｇで
あった。この発泡粒子の気泡膜断面を電子顕微鏡で観察
した。観察されたｂ／ａ値、ａ／ｃ値、および気泡膜断
面におけるゴム粒子の層状構造の有無、発泡剤保持性、
独立気泡率を表３に示す。また、ＨＩＰＳ−１、２、３
で得られた発泡粒子の気泡膜を厚み方向の断面で見たと
きに気泡膜厚みを一辺とする正方形内に少なくともゴム
粒子の一部が存在する、ゴム粒子の数（以下、ＮＲ）は
各々、２０個、１６個、２４個であった。また、得られ
た発泡粒子を発泡スチロール用の成形機に内蔵された成
形型内で融着一体化させ、密度が０．０２０ｇ／ｃ
ｍ3 、所定の形状をした、３０ｋｇのＣＲＴモニター梱
包用緩衝包装材を成形した。The expanded beads recovered from the foaming machine were aged in a room at 20 ° C. for 24 hours. The obtained foamed particles had an apparent density of 0.033 g / cm 3 . HIPS-1, HI
The average weight per PS-2 and HIPS-3 particles was 0.70 mg, 0.68 mg, and 0.69 mg, respectively. The cross section of the foam film of the foamed particles was observed with an electron microscope. The observed b / a value, a / c value, the presence or absence of a layered structure of rubber particles in the cross section of the foam film, the foaming agent retention,
Table 3 shows the closed cell ratio. In addition, HIPS-1, 2, 3
When the cell membrane of the foamed particles obtained in the above is viewed in a cross section in the thickness direction, at least a part of the rubber particles exists in a square having the cell membrane thickness as one side, and the number of rubber particles (hereinafter, NR) is , 20, 16, and 24. Further, the obtained foamed particles are fused and integrated in a molding die built in a molding machine for styrofoam, and have a density of 0.020 g / c.
A 30 kg cushioning packaging material for CRT monitor packaging having a predetermined shape of m 3 was molded.
【００７７】（成形体の耐割れ性、外観評価）得られた
成形体の実用落下割れ性、及び外観の粒子間空隙数を評
価した。結果を表３に示す。いずれも良好なものであっ
た。(Evaluation of Cracking Resistance and Appearance of Molded Article) Practical drop cracking characteristics of the obtained molded article and the number of voids between particles in appearance were evaluated. Table 3 shows the results. All were good.
【００７８】実施例２ ハイシスポリブタジエンゴムをスチレンモノマー中に溶
解し、９．５ｗｔ％の溶液とした。この溶液１００重量
部に１，１−ビス（ｔ−ブチルパーオキシ）シクロヘキ
サン０．０４重量部、０．０６重量部のｔ−ドデシルメ
ルカプタンを添加し、撹拌しながら１１０℃で重合を開
始し４時間後、１３５℃で２時間、更に１５０℃で２時
間と順次昇温させ重合を行った。最終的に重合液を加熱
真空下の脱揮装置に送り未反応スチレンを除去し重合体
固形物ＨＩＰＳ−４を得た。ＨＩＰＳ−４樹脂中のブタ
ジエン成分は１２．３ｗｔ％、［η］は０．８０、ＳＷ
Ｉは９．５であった。また分散ゴム粒子はサラミ構造で
平均粒子径は１．３μｍであった。ポリブタジエンのス
チレンモノマ−中濃度を５．５ｗｔ％とし、重合温度条
件を変えた外は、ＨＩＰＳ−４と同様の重合を行いＨＩ
ＰＳ−５を得た。ＨＩＰＳ−５の性状を表１に示す。Example 2 High cis polybutadiene rubber was dissolved in styrene monomer to prepare a 9.5 wt% solution. To 100 parts by weight of this solution, 0.04 parts by weight of 1,1-bis (t-butylperoxy) cyclohexane and 0.06 parts by weight of t-dodecylmercaptan were added, and polymerization was started at 110 ° C. while stirring. After the lapse of time, the temperature was increased in order at 135 ° C. for 2 hours and further at 150 ° C. for 2 hours to carry out polymerization. Finally, the polymer solution was sent to a devolatilizer under heating and vacuum to remove unreacted styrene to obtain a polymer solid HIPS-4. Butadiene component in HIPS-4 resin is 12.3 wt%, [η] is 0.80, SW
I was 9.5. The dispersed rubber particles had a salami structure and an average particle diameter of 1.3 μm. Except that the concentration of polybutadiene in the styrene monomer was set to 5.5 wt% and the polymerization temperature conditions were changed, the same polymerization as in HIPS-4 was carried out and HI
PS-5 was obtained. Table 1 shows the properties of HIPS-5.
【００７９】ＨＩＰＳ−４及び５を実施例１で用いたも
のと同様の押出含浸装置に供給し、押出機内で溶融させ
つつ、イソペンタンを樹脂１００ｇ量について０．１３
ｇモル量比率にポンプで一定量ずつ加圧供給し、樹脂と
混練混合し、更に１３０℃の溶融状態に２５分滞留させ
た後、冷却装置で適温に冷却しダイ装置に設けられた多
数の細孔より６０℃の水中に押出しつつ回転式カッター
でカットし、発泡性樹脂粒子を得た。HIPS-4 and 5 were fed into an extrusion impregnation apparatus similar to that used in Example 1 and, while being melted in the extruder, isopentane 0.13 per 100 g resin amount.
The mixture is supplied under pressure by a pump at a fixed amount in a molar amount ratio, kneaded and mixed with the resin, and is further kept in a molten state at 130 ° C. for 25 minutes. It was cut with a rotary cutter while being extruded into water at 60 ° C. from the pores to obtain expandable resin particles.
【００８０】得られた発泡性樹脂粒子を実施例１と同様
に発泡、熟成させ、見掛け密度が０．０３３ｇ／ｃｍ3
の発泡粒子とした。得られた発泡粒子の平均重量は０．
７５ｍｇであった。この発泡粒子の性状を表３に示す。
また、発泡粒子のＮＲはＨＩＰＳ−４のものが７個、Ｈ
ＩＰＳ−５のものが６個であった。また、得られた発泡
粒子を実施例１と同様にして成形し、密度が０．０２０
ｇ／ｃｍ3 、所定の形状をした、３０ｋｇのＣＲＴモニ
ター梱包用緩衝包装材を成形した。得られた成形体の性
能を表２に示した。いずれも良好なものであった。The expandable resin particles obtained were foamed and aged in the same manner as in Example 1 to give an apparent density of 0.033 g / cm 3.
Of expanded particles. The average weight of the obtained expanded particles is 0.1.
75 mg. Table 3 shows the properties of the expanded particles.
The NR of the expanded particles was 7 for HIPS-4, and
There were six IPS-5 devices. Further, the obtained expanded particles were molded in the same manner as in Example 1, and the density was 0.020.
A 30 kg cushioning packaging material for packaging a CRT monitor having a predetermined shape of g / cm 3 was molded. Table 2 shows the performance of the obtained molded body. All were good.
【００８１】実施例３ ブタジエン成分が６０ｗｔ％であるスチレン−ブタジエ
ンブロック共重合体をスチレンモノマーに溶解させ、１
２ｗｔ％の溶液とした。この溶液を撹拌下で重合するこ
とによって得た平均粒子径が０．２μｍでコアシェル構
造を有し、樹脂中のブタジエン成分が９ｗｔ％のゴム変
性ポリスチレン（Ｉ）と、１−４シス含量が９６％のハ
イシスポリブタジエンをスチレンモノマーに溶解させ、
９ｗｔ％とした。この溶液を撹拌下で重合することによ
って得た平均粒子径が１．４μｍでサラミ構造を有し、
樹脂中のブタジエン成分が１２ｗｔ％のゴム変性ポリス
チレン（II）とを（Ｉ）９対（II）１の比率で混合し、
得られた樹脂をＨＩＰＳ−６とした。Example 3 A styrene-butadiene block copolymer having a butadiene content of 60 wt% was dissolved in a styrene monomer, and 1
A 2 wt% solution was obtained. This solution was polymerized under stirring to obtain a rubber-modified polystyrene (I) having an average particle size of 0.2 μm, a core-shell structure, a butadiene component in the resin of 9 wt%, and a 1-4 cis content of 96%. % High cis polybutadiene dissolved in styrene monomer,
9 wt%. The average particle size obtained by polymerizing this solution under stirring has a salami structure of 1.4 μm,
A rubber-modified polystyrene (II) in which a butadiene component in the resin is 12 wt% is mixed in a ratio of (I) 9 to (II) 1,
The obtained resin was designated as HIPS-6.
【００８２】平均粒子径が０．３μｍでコアシェル構造
を有し、樹脂中のブタジエン成分が８ｗｔ％のゴム変性
ポリスチレン（III ）と、平均粒子径が１．７μｍでサ
ラミ構造を有し、樹脂中のブタジエン成分が８ｗｔ％の
ゴム変性ポリスチレン（IV）とを（III ）８対（IV）２
の比率で混合し、得られた樹脂をＨＩＰＳ−７とした。
ＨＩＰＳ−６、７を用いて実施例１と同様に発泡性樹脂
粒子、発泡粒子、発泡粒子成形体を製作し、その性状、
性能を表３に示す。いずれも良好なものであった。発泡
粒子の平均重量はＨＩＰＳ−６、ＨＩＰＳ−７で各々
０．６４ｍｇ、０．６２ｍｇであった。The rubber-modified polystyrene (III) having an average particle diameter of 0.3 μm and a core-shell structure, the butadiene component in the resin being 8 wt%, and the salami structure having an average particle diameter of 1.7 μm Rubber modified polystyrene (IV) containing 8 wt% of butadiene component of (III) 8 vs. (IV) 2
And the resulting resin was designated as HIPS-7.
Using HIPS-6 and 7, foamable resin particles, foamed particles, and a foamed molded article were produced in the same manner as in Example 1,
The performance is shown in Table 3. All were good. The average weight of the expanded particles was 0.64 mg and 0.62 mg for HIPS-6 and HIPS-7, respectively.
【００８３】実施例４ ＨＩＰＳ−１を用い、実施例１と同様にして発泡剤を含
浸させた発泡性粒子を作製した。得られた発泡性樹脂粒
子を１０２℃保持時間を３０秒（条件１）、２０秒（条
件２）、１５秒（条件３）とした外は、ＨＩＰＳ−１と
同様の条件で発泡させ、見掛け密度が０．０１８ｇ／ｃ
ｍ3 （条件１）、０．０２３ｇ／ｃｍ3（条件２）、
０．０４０ｇ／ｃｍ3 （条件３）の発泡樹脂粒子を作製
した。見掛け密度０．０１８ｇ／ｃｍ3 の発泡粒子を実
施例１と同様の金型で成形し、かさ密度０．０１１ｇ／
ｃｍ3 の成形体を得た。また、見掛け密度０．０２３ｇ
／ｃｍ3 の発泡粒子からはかさ密度０．０１４ｇ／ｃｍ
3 の成形体を得た。見掛け密度０．０４０ｇ／ｃｍ3 の
発泡粒子からはかさ密度０．０２４ｇ／ｃｍ3 の成形体
を得た。各々の発泡粒子、成形体の性状、性能を表４に
示す。Example 4 Using HIPS-1, in the same manner as in Example 1, expandable particles impregnated with a foaming agent were produced. The obtained expandable resin particles were foamed under the same conditions as those of HIPS-1, except that the holding time at 102 ° C. was changed to 30 seconds (condition 1), 20 seconds (condition 2), and 15 seconds (condition 3). Density is 0.018g / c
m 3 (condition 1), 0.023 g / cm 3 (condition 2),
0.040 g / cm 3 (condition 3) foamed resin particles were produced. Foamed particles having an apparent density of 0.018 g / cm 3 were molded in the same mold as in Example 1 to obtain a bulk density of 0.011 g /
A molded product of cm 3 was obtained. In addition, apparent density 0.023g
Bulk density of 0.014 g / cm from expanded particles of / cm 3
A molded product of No. 3 was obtained. The foamed particles of apparent density 0.040 g / cm 3 to obtain a molded body having a bulk density of 0.024 g / cm 3. Table 4 shows the properties and performance of each foamed particle and molded article.
【００８４】実施例５ ＨＩＰＳ−４を用い、実施例４と同様にして発泡粒子、
成形体を作製した。各々の発泡粒子、成形体の性状、性
能を表４に示す。Example 5 Using HIPS-4, expanded particles were prepared in the same manner as in Example 4.
A molded body was produced. Table 4 shows the properties and performance of each foamed particle and molded article.
【００８５】比較例１ ゴム変性ポリスチレンの［η］が０．５２、ＳＷＩが１
０．５であるＨＩＰＳ−８を用いた他は実施例１と同様
にして発泡粒子、成形体を作製した。各々の発泡粒子、
成形体の性状、性能を表５に示す。得られた発泡粒子の
平均重量は０．６５ｍｇであり、発泡粒子気泡膜のｂ／
ａ値は８であり、発泡粒子のガス保持性、成形体の耐割
れ性、外観は劣るものであった。Comparative Example 1 Rubber modified polystyrene [η] was 0.52 and SWI was 1.
Except for using HIPS-8 of 0.5, foamed particles and molded articles were produced in the same manner as in Example 1. Each foam particles,
Table 5 shows the properties and performance of the molded product. The average weight of the obtained expanded particles was 0.65 mg, and b /
The a value was 8, and the gas retention of the foamed particles, the crack resistance of the molded article, and the appearance were poor.
【００８６】比較例２ ゴム変性ポリスチレンの［η］が０．９２、ＳＷＩが
８．５であるＨＩＰＳ−９を用いた他は実施例１と同様
にして発泡粒子、成形体を作製した。各々の発泡粒子、
成形体の性状、性能を表５に示す。得られた発泡粒子の
平均重量は０．６８ｍｇであり、成形体の耐割れ性はや
や劣るものであった。Comparative Example 2 Foamed particles and a molded product were produced in the same manner as in Example 1 except that HIPS-9 having [η] of rubber modified polystyrene and SWI of 8.5 was used. Each foam particles,
Table 5 shows the properties and performance of the molded product. The average weight of the obtained expanded beads was 0.68 mg, and the crack resistance of the molded product was slightly inferior.
【００８７】比較例３ ゴム変性ポリスチレンの［η］が０．８５、ＳＷＩが
４．５であるＨＩＰＳ−１０を用いた他は実施例１と同
様にして発泡粒子、成形体を作製した。各々の発泡粒
子、成形体の性状、性能を表５に示す。得られた発泡粒
子の平均重量は０．７０ｍｇであり、発泡粒子気泡膜の
ｂ／ａ値は７であり、発泡粒子のガス保持性、成形体の
耐割れ性、外観は劣るものであった。Comparative Example 3 Foamed particles and a molded product were prepared in the same manner as in Example 1 except that HIPS-10 having [η] of rubber-modified polystyrene and SWI of 0.85 was used. Table 5 shows the properties and performance of each expanded particle and molded article. The average weight of the obtained expanded particles was 0.70 mg, the b / a value of the expanded particle foam film was 7, and the gas retention of the expanded particles, the crack resistance of the molded product, and the appearance were inferior. .
【００８８】比較例４ ゴム変性ポリスチレンの［η］が０．６２、ＳＷＩが１
４．５であるＨＩＰＳ−１１を用いた他は実施例１と同
様にして発泡粒子、成形体を作製した。各々の発泡粒
子、成形体の性状、性能を表５に示す。得られた発泡粒
子の平均重量は０．６８ｍｇであり、成形体の耐割れ
性、外観はやや劣るものであった。Comparative Example 4 [η] of rubber-modified polystyrene was 0.62 and SWI was 1.
Except for using HIPS-11 which was 4.5, foamed particles and molded articles were produced in the same manner as in Example 1. Table 5 shows the properties and performance of each expanded particle and molded article. The average weight of the obtained foamed particles was 0.68 mg, and the molded article was slightly inferior in crack resistance and appearance.
【００８９】比較例５ ＨＩＰＳ−１、４、６を用い、押出し含浸時の１３０℃
滞留時間を５分としたた他は実施例１と同様にして発泡
粒子、成形体を作製した。各々の発泡粒子、成形体の性
状、性能を表５に示す。得られた発泡粒子の平均重量は
ＨＩＰＳ−１、４、６で各々、０．７０ｍｇ、０．６９
ｍｇ、０．７０ｍｇ、であり、発泡粒子気泡膜のｂ／ａ
の値はＨＩＰＳ−１、４、６で各々７、６、７であり、
発泡粒子、成形体の性能はやや劣るものであった。Comparative Example 5 HIPS-1, 4, and 6 were used, and extrusion impregnation was performed at 130 ° C.
Except that the residence time was set to 5 minutes, foamed particles and molded articles were produced in the same manner as in Example 1. Table 5 shows the properties and performance of each expanded particle and molded article. The average weight of the obtained expanded particles was 0.70 mg, 0.69 for HIPS-1, 4, and 6, respectively.
mg, 0.70 mg, and b / a of the foamed particle cell membrane.
Are 7, 6, 7 for HIPS-1, 4, 6 respectively.
The performance of the expanded particles and the molded article was slightly inferior.
【００９０】比較例６ ゴム変性ポリスチレンの粒子平均ゴム粒径が０．１２μ
ｍであるＨＩＰＳ−１２を用いた他は実施例１と同様に
して発泡粒子、成形体を作製した。各々の発泡粒子、成
形体の性状、性能を表６に示す。得られた発泡粒子の平
均重量は０．７０ｍｇであり、発泡粒子気泡膜のａ／ｃ
値は０．００９であり、成形体の耐割れ性は劣るもので
あった。Comparative Example 6 Rubber-Modified Polystyrene Particles Average rubber particle size is 0.12μ
Except for using HIPS-12 as m, foamed particles and molded articles were produced in the same manner as in Example 1. Table 6 shows the properties and performance of each expanded particle and molded article. The average weight of the obtained expanded particles was 0.70 mg, and the a / c
The value was 0.009, and the molded article had poor crack resistance.
【００９１】比較例７ ゴム変性ポリスチレンのゴム粒子平均ゴム粒径が３．３
μｍであるＨＩＰＳ−１３を用いた他は実施例１と同様
にして発泡粒子、成形体を作製した。各々の発泡粒子、
成形体の性状、性能を表６に示す。得られた発泡粒子の
平均重量は０．７５ｍｇであり、発泡粒子気泡膜のａ／
ｃ値は０．２１であり、発泡粒子、成形体の性能は劣る
ものであった。Comparative Example 7 Rubber Particles of Rubber Modified Polystyrene The average rubber particle diameter is 3.3.
Except for using HIPS-13 having a thickness of μm, foamed particles and molded articles were produced in the same manner as in Example 1. Each foam particles,
Table 6 shows the properties and performance of the molded product. The average weight of the obtained expanded particles was 0.75 mg, and a /
The c value was 0.21, and the performance of the foamed particles and the molded article was inferior.
【００９２】比較例８ ＨＩＰＳ−１をポリスチレン樹脂と混合した後押し出し
機中で溶融混合させた。得られた樹脂をＨＩＰＳ−１４
とした。ＨＩＰＳ−１４のブタジエン成分の含有量を測
定したところ３ｗｔ％であった。ＨＩＰＳ−１４を用い
た他は実施例１と同様にして発泡粒子、成形体を作製し
た。各々の発泡粒子、成形体の性状、性能を表６に示
す。得られた発泡粒子の平均重量は０．６６ｍｇであ
り、発泡粒子の気泡膜断面におけるゴム粒子は層状構造
を成しておらず、成形体の耐割れ性はやや劣るものであ
った。Comparative Example 8 HIPS-1 was mixed with polystyrene resin and then melt mixed in an extruder. The obtained resin is HIPS-14
And When the butadiene component content of HIPS-14 was measured, it was 3 wt%. Except that HIPS-14 was used, a foamed particle and a molded article were produced in the same manner as in Example 1. Table 6 shows the properties and performance of each expanded particle and molded article. The average weight of the obtained foamed particles was 0.66 mg, the rubber particles in the cross section of the foam film of the foamed particles did not form a layered structure, and the crack resistance of the molded product was slightly inferior.
【００９３】比較例９ ＨＩＰＳ−１０を用いた他は実施例４と同様にして見掛
け密度が０．０１８ｇ／ｃｍ3 、０．０２３ｇ／ｃ
ｍ3 、０．０４０ｇ／ｃｍ3 の発泡樹脂粒子、及びかさ
密度０．０１１ｇ／ｃｍ3 、０．０１４ｇ／ｃｍ3 、
０．０２４ｇ／ｃｍ3の成形体を得た。各々の発泡粒
子、成形体の性状、性能を表６に示す。得られた発泡粒
子の平均重量はいずれも０．７２ｍｇであり、気泡膜断
面のｂ／ａ値はいずれも１０未満であり、成形体の性能
は劣ったものであった。Comparative Example 9 The apparent density was 0.018 g / cm 3 and 0.023 g / c in the same manner as in Example 4 except that HIPS-10 was used.
m 3, the foamed resin particles 0.040 g / cm 3, and bulk density of 0.011g / cm 3, 0.014g / cm 3,
A molded body of 0.024 g / cm 3 was obtained. Table 6 shows the properties and performance of each expanded particle and molded article. The average weight of each of the obtained expanded particles was 0.72 mg, and the b / a value of each of the cross sections of the cell membrane was less than 10, and the performance of the molded article was inferior.
【００９４】[0094]
【表１】 [Table 1]
【００９５】[0095]
【表２】 [Table 2]
【００９６】[0096]
【表３】 [Table 3]
【００９７】[0097]
【表４】 [Table 4]
【００９８】[0098]
【表５】 [Table 5]
【００９９】[0099]
【表６】 [Table 6]
【０１００】[0100]
【発明の効果】本発明の製法により得られるゴム変性ポ
リスチレン系樹脂からなる発泡粒子を用いて成形した成
形体は、比較的重量が大きく、衝撃頻度が高いと予想さ
れる包装貨物用の緩衝材として好適に用いられる。成形
体は耐割れ性に優れていることから緩衝材の使用量を削
減できる。また、ゴム成分配合による柔軟性を生かし、
家屋や槽類の断熱材としても有用である。本発明の発泡
粒子及びその発泡粒子成形体は汎用設備を用いて、比較
的安価に製造でき、しかも発泡粒子の発泡剤ガス保持性
が良く、従って発泡粒子の膨脹能が大きいため成形体の
外観が良好である等の優れた性能を持ち、さらに使用済
み成形体を汎用のスチロールを違和なく混合リペレット
化できる等の利点を持つ。このように本発明の発泡粒子
は発泡体成形加工分野において極めて有用なものであ
る。EFFECTS OF THE INVENTION A molded article molded using expanded particles made of a rubber-modified polystyrene resin obtained by the method of the present invention has a relatively large weight and is a shock absorbing material for packaged cargo expected to have a high impact frequency. Is preferably used as. Since the molded body is excellent in crack resistance, the amount of the cushioning material used can be reduced. Also, by utilizing the flexibility of the rubber component blend,
It is also useful as a heat insulating material for houses and tanks. The expanded beads and the expanded beads molded product of the present invention can be produced at a relatively low cost by using general-purpose equipment, and the expanded particles have a good gas retention for the foaming agent, and therefore the expanded particles have a large expansion ability, so that the appearance of the molded product is high. It has excellent properties such as good performance, and has the advantage of being able to re-pelletize a used molded product with general-purpose styrene without mixing. Thus, the expanded particles of the present invention are extremely useful in the field of foam molding.
【図１】本発明における気泡膜断面でのゴム粒子の分散
状態を示す模式説明図である。FIG. 1 is a schematic explanatory view showing a dispersion state of rubber particles in a cross section of a bubble film in the present invention.
【図２】本発明の発泡粒子の断面状態を示す模式説明図
である。FIG. 2 is a schematic explanatory view showing a cross-sectional state of a foamed particle of the present invention.
【図３】図２の破線部分の拡大図である。FIG. 3 is an enlarged view of a portion indicated by a broken line in FIG. 2;
【図４】本発明における実用落下テストの包装形態を示
す模式説明図である。FIG. 4 is a schematic explanatory view showing a packaging form of a practical drop test according to the present invention.
１ 気泡断面図 ２ 気泡膜面 ３ ポリスチレン系連続相 ４ ゴム粒子のポリスチレン系成分部 ５ ゴム粒子のブタジエン系成分部 ６ 発泡粒子 ７ 発泡粒子断面 ８ 気泡 ９ 気泡膜 1 Cell Cross Section 2 Cell Membrane Surface 3 Polystyrene-based Continuous Phase 4 Polystyrene-based Component Part of Rubber Particles 5 Butadiene-based Component Part of Rubber Particles 6 Foamed Particles 7 Foamed Particle Cross Section 8 Bubbles 9 Cell Film
Claims (1)
を製造する方法であって、下記工程からなることを特徴
とするポリスチレン系発泡粒子の製造方法。 （１）ポリスチレン系樹脂の連続相とブタジエン系ゴム
粒子の分散相とから成るゴム変性ポリスチレン系樹脂で
あって、該連続相の３０℃トルエン中での極限粘度が
０．６以上０．９以下であり、該ブタジエン系ゴム粒子
の２５℃トルエン中での膨潤指数が６．５以上、１３．
５以下であるゴム変性ポリスチレン樹脂を、押出し機内
で発泡剤と加熱溶融状態で混合し、溶融混合物を得る工
程 （２）前記溶融混合物を押出機内において、５０ｋｇ／
ｃｍ2 Ｇ以上、３００ｋｇ／ｃｍ2 Ｇ以下の圧力下で、
１３０℃以上の温度に１５分以上保持し、発泡剤を含浸
させたゴム変性ポリスチレン樹脂を得る工程 （３）前記発泡剤を含浸させたゴム変性ポリスチレン樹
脂を押出した後、切断し、粒状にすることによって発泡
性粒子を得る工程 （４）前記発泡性粒子を加熱する工程1. A method for producing expanded beads from a rubber-modified polystyrene resin, which comprises the following steps. (1) A rubber-modified polystyrene-based resin comprising a continuous phase of polystyrene-based resin and a dispersed phase of butadiene-based rubber particles, wherein the continuous phase has an intrinsic viscosity of 0.6 or more and 0.9 or less in toluene at 30 ° C. And the swelling index of the butadiene rubber particles in toluene at 25 ° C. is 6.5 or more, 13.
A step of mixing a rubber-modified polystyrene resin of 5 or less with a foaming agent in a heating and melting state in an extruder to obtain a molten mixture. (2) The molten mixture in an extruder is 50 kg /
Under a pressure of not less than cm 2 G and not more than 300 kg / cm 2 G,
Step of obtaining a rubber-modified polystyrene resin impregnated with a foaming agent by holding at a temperature of 130 ° C. or higher for 15 minutes or more (3) Extruding the rubber-modified polystyrene resin impregnated with the foaming agent, and then cutting it into granules To obtain expandable particles (4) Step of heating the expandable particles
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8246889A JPH09104782A (en) | 1993-04-27 | 1996-08-30 | Manufacture of polystyrene foamed particle |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12214393 | 1993-04-27 | ||
| JP5-122143 | 1993-04-27 | ||
| JP8246889A JPH09104782A (en) | 1993-04-27 | 1996-08-30 | Manufacture of polystyrene foamed particle |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6110248A Division JP2600607B2 (en) | 1993-04-27 | 1994-04-27 | Method for producing expanded polystyrene-based particles and molded polystyrene-based expanded particles |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH09104782A true JPH09104782A (en) | 1997-04-22 |
Family
ID=26459335
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8246889A Withdrawn JPH09104782A (en) | 1993-04-27 | 1996-08-30 | Manufacture of polystyrene foamed particle |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH09104782A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6232358B1 (en) | 1997-09-12 | 2001-05-15 | Mitsubishi Chemical Foam Plastic Corporation | Expandable rubber-modified styrene resin compositions |
| JP2012077114A (en) * | 2010-09-30 | 2012-04-19 | Sekisui Plastics Co Ltd | Expandable polystyrene resin particle, method for producing the same, polystyrene resin pre-expanded particle and polystyrene resin foam-molded product |
| CN114479161A (en) * | 2020-10-27 | 2022-05-13 | 无锡兴达泡塑新材料股份有限公司 | Preparation method of rubber modified high-toughness EPS |
-
1996
- 1996-08-30 JP JP8246889A patent/JPH09104782A/en not_active Withdrawn
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6232358B1 (en) | 1997-09-12 | 2001-05-15 | Mitsubishi Chemical Foam Plastic Corporation | Expandable rubber-modified styrene resin compositions |
| JP2012077114A (en) * | 2010-09-30 | 2012-04-19 | Sekisui Plastics Co Ltd | Expandable polystyrene resin particle, method for producing the same, polystyrene resin pre-expanded particle and polystyrene resin foam-molded product |
| CN114479161A (en) * | 2020-10-27 | 2022-05-13 | 无锡兴达泡塑新材料股份有限公司 | Preparation method of rubber modified high-toughness EPS |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A300 | Withdrawal of application because of no request for examination |
Free format text: JAPANESE INTERMEDIATE CODE: A300 Effective date: 20010703 |