【発明の詳細な説明】[Detailed description of the invention]
本発明は均一且つ微細な独立気泡構造を持つ高
発泡体を可能とするアゾジカルボンアミドに関す
る。即ち、Ｘ線回折角2θ＝28.9゜の回折角強度I1
と、2θ＝15.8゜の回折角強度I2との強度比I1／I2が
1.7〜4.0で、且つ面積径の累積カーブの50％に対
応する粒径が６〜15μである、従来未知の発泡剤
用アゾジカルボンアミドに関する。
近年、各種の天然又は、合成樹脂に発泡剤を配
合して発泡体を得る方法が広く普及し、これら発
泡体は例えば断熱材、クツシヨン材、包装梱包
材、防音材、パツキング材、浮揚材、電気絶縁
材、構造材、家庭雑貨用品等多くの用途がある。
しかして、発泡体の緩衝性、弾力性、断熱性、防
音性、表面の平滑さ等の物性は、発泡体の気泡構
造と密接な関係があり、特に高発泡倍率の発泡体
で気泡構造の均一且つ微細なことが強く要望され
てきた。従来、このような要望に応えるため、
色々の提案がなされている。例えば、特公昭46−
3876や特公昭52−39662のような樹脂の改質、あ
るいは気泡調整剤や増核剤の添加、更には特公昭
54−25972の如き架橋助剤の添加等があるが、使
用される発泡剤の吟味がなされていないため、必
らずしも充分に満足出来るものでない。
かかる用途に使用される加熱分解型発泡剤は多
くあるが、分解挙動を助剤で任意に調整出来るこ
と、分解ガス量が多く且つ分解ガスの主成分が独
立気泡形成に好ましい窒素が主体であり、分解残
渣が無色で不快臭や汚染性がなく、しかも安価で
あること等から、アゾジカルボンアミド（以下、
ACと略記することあり）がその主流を占めてい
る。しかしながら、高発泡倍率〔低密度〕の発泡
体を作るためには多量の発泡剤を使用するので発
泡時分解ガスの圧力が大きく、発泡体の気泡が粗
大となり又気泡も不均一となることをまぬがれな
かつた。しかして、均一微細な気泡を形成させる
ための発泡剤の提案として、例えば特開昭49−
53956がある。即ち、発泡剤として平均粒子径
（注、重量基準による粒度分布から求めたメジア
ン径）10〜30μであり、且つ5μを越える粒子を90
重量％以上含む化学分解型発泡剤を使用すれば気
泡径の小さい発泡体が得られるというものであ
る。換言すれば、どういう製造条件で作られた発
泡剤でも例えば粉砕・分級によつて、均一微細な
気泡を形成する発泡剤が得られるというものであ
るが、この提案は発泡剤の製造条件とその結晶構
造を無視したものであり、極めて不十分な提案で
あつた。
本発明者らは、均一微細な独立気泡構造を形成
させることが極めて困難な高発泡倍率発泡体のた
めの発泡剤の製造を目的として鋭意研究の結果、
従来未知のＸ線回折特性を有するACが存在し、
製造出来ること、及びこのＸ線回折特性を有する
ACは、均一且つ微細な独立気泡構造の発泡体を
可能とし、従来ACの諸欠陥を改善出来ることを
見出し本発明に至つたものである。
従つて、本発明の目的は上述の如き欠陥の克服
された、樹脂発泡の用途等を有するACを提供す
るにある。
本発明の目的及び利点は、以下の記載から一層
明らかになるであろう。
従来のACは、ヒドラゾジカルボンアミドを種
種の酸化剤で酸化することによつて作られる。酸
化剤としては、塩素ガス、次亜塩素酸ソーダ、過
塩素酸ソーダのような塩素化合物や、硝酸アンモ
ニウム、酸化窒素のような窒素化合物、重クロム
酸カリ、重クロム酸ソーダのような重クロム酸化
合物、過酸化水素のような過酸化物等が用いられ
ている。このような公知の方法で製造された、面
積径の累積カーブの50％に対応する粒径（以下
「平均面積粒径」と略することあり）が５〜15μ
の従来のアゾジカルボンアミドは、Ｘ線回折角2θ
＝28.9゜の回折角強度I1と2θ＝15.8゜の回折角強度I2
との強度比I1／I2（以下「Ｘ線回折角強度比I1／
I2」と略すことあり）は、1.7未満或いは4.0を越
えて大であり、このようなACは、本発明のACが
有する優れた効果は得られない。
本発明のACはＸ線回折角強度比I1／I2が1.7〜
4.0で平均面積粒径が６〜15μでなければならない
が、Ｘ線回折角強度比I1／I2は好ましくは1.8〜
3.8、特に好ましくは1.9〜3.5であり、平均面積粒
径は好ましくは７〜14μ、特に好ましくは８〜
13μである。Ｘ線回折角強度比I1／I2が1.7未満と
過小なものは、結晶構造的に１０１面が発達して
いない不定形のものが多く混在しており、均一微
細な独立気泡を形成しない。又、4.0を越えて過
大なものは、結晶の定形化が進み結晶の大きさも
揃つてくるが、製法上収率の低下を招くので実用
的でなく好ましくない。一方、ACの平均面積粒
径が5μ以下と過小なものは、分解速度が速すぎ
て樹脂の混練成形時分解を起しやすく、又発泡炉
での樹脂の膨脹が急激に起るため気泡径が粗大と
なり発泡体の表面からガスが抜けて肌荒れを起し
好ましくない。又、15μ以上と過大なものは、粒
度の巾が大きいため発泡体に発泡ムラが生じ均一
な気泡とならず、過大な粗粒子は未分解で残り発
泡体が白く仕上らない等の欠点を有し好ましくな
い。
本発明のACのＸ線回折角強度比I1／I2を第１
図により更に詳しく説明する。第１図は本発明の
ACのＸ線回折図の一例で、ここでＸ線回折の測
定はACのサンプルを３２５メツシユ以下に粉砕
して得られた微細結晶粉末を回折ホルダーに充填
した試料について、自動記録式粉末Ｘ線回折装置
（日本電子(株)製〔型式JDX−8SH〕、線源はCu−
Kd線，出力30KV，14mA）で行なつた。第１図
の横軸は回折角2θ（単位：度）を、縦軸は回折強
度（単位：cps，count per second）を表わし、
2θ＝28.9゜の回折強度は図中のI1、2θ＝15.8゜の回折
強度はI2で示され、本発明で言うＸ線回折強度比
はI1／I2で計算される。
又、本発明に於けるACの粒径の測定法を、以
下に詳しく説明する。粒径乃至は粒度の測定器は
種々開発されているが、本発明者等は液体中に於
ける固体粒子の沈降速度を応用した光透過式粒度
分布測定器（(株)セイシン企業製〔型式SK型〕）を
使用した。即ち、この光透過式粒度分布測定器が
示す面積径の累積カーブの50％に対応する粒径で
ある。（この値は比表面積計の平均粒径と基本的
に一致するので、該機器による測定値を採用して
もよい。）この面積径の累積カーブは重量累積カ
ーブに換算出来るが、粒子が球体或いは立方体に
近い場合はよいが、直方体或いは針状のような場
合重量換算することに無理がある。例えば、平均
面積粒径10μ，6μ，3μのあるACを重量基準によ
る平均粒径に換算したところ、夫々22μ，22μ，
11μとなつた。従つて、本発明者等はより明確な
判定基準を与える粒径の尺度として、面積径を採
用したものである。
本発明のような特殊なACは、例えば次のよう
な方法で製造することが出来る。即ち、従来公知
の方法で製造されたACを分解させ難い媒体中に
投入し、撹拌しながら45〜100℃で４時間乃至15
分間加熱処理し、次いで冷却しながら結晶形を整
えることによつて、本発明のACを得ることが出
来る。加熱処理は、ヒドラゾジカルボンアミドの
酸化反応完結後行なつてもよいし、反応末期に漸
次温度を上昇させてもよい。
この方法で使用する媒体は、アルカリ性の場合
ACを分解させるので弱酸性であることが、肝要
であるが、経済的或いは公害上の見地から水の使
用が実用的である。又この際、ACの分解温度を
調整したり、ガス発生量を増大させたり、固結を
防止する等、ACの品質を改質或いは向上させる
目的で薬剤を加え、結晶中に含ませたり表面に附
着させたりすることは何ら妨げない。媒体中の
ACのスラリー濃度は、撹拌機の能力と生産性を
考慮すれば５〜40重量％、好ましくは15〜30重量
％である。更に加熱処理温度は、低いと時間を長
くしても結晶化が進まず、逆に高過ぎるとACが
分解してヒドラゾジカルボンアミドを生成し収率
が低下するので好ましくない。加熱温度は45〜
100℃、好ましくは55〜100℃で、処理時間は４時
間乃至10分間、好ましくは３時間乃至30分間であ
る。熱処理後の冷却方法は、得ようとする粒径に
よつて急冷或いは除冷すればよい。尚、必要に応
じ粉砕分級することを妨げない。
上に述べたような方法によつて、本発明の特殊
なACは製造可能であるが、必らずしも上述の方
法による必要はなく、特に制限されるものではな
い。かかるACが発泡剤として配合され、発泡体
が製造される樹脂としては、天然、合成各種樹脂
及びこれらのコーポリマー或いはブレンド等があ
り、特に制限されるものではない。例えば、ポリ
エチレン、ポリプロピレン等のポリオレフイン
系、ナイロン等のポリアミド系、ポリエステル
系、ゴム系、セルローズ系、ポリビニール系等の
熱可塑性樹脂、及びユリア系、フエノール系、メ
ラミン系、エポキシ系のような熱硬化性樹脂で、
発泡剤の分解によつて発生する気体を利用して膨
脹しうるものすべてに利用可能であるが、好まし
くはポリオレフイン系、ポリビニール系の樹脂に
用いられる。
上記樹脂類には、必要に応じて可塑剤、安定
剤、セル調整剤、架橋剤、架橋助剤、滑剤、充填
剤、着色剤、紫外線吸収剤、帯電防止剤、界面活
性剤、発泡助剤等の添加剤を含んでいてもよい。
本発明のACは、従来公知のACに較べて分解温
度は近似しているので、使用に際しては特に配慮
を要しないが、必要に応じ分解促進剤を使用して
もよく、特に高発泡倍率の発泡体では架橋助剤の
使用が好ましい。又樹脂に対する本発明ACの配
合量は、得ようとする発泡倍率にあわせ適宜使用
すればよい。
本発明の適用される発泡方法は、例えば押出成
形機などにより混練押出成形して発泡組成物を
得、これを熱風、赤外ランプ照射、高周波電流に
よる誘導加熱等により加熱して、常圧下で発泡剤
を分解せしめて発泡体を作る方法などに適用出来
る。
このように、本発明ACは工業的に簡単に製造
出来、又均一且つ微細な独立気泡を持つた発泡体
を容易に且つ確実に製造することが出来る。特に
断熱性、緩衝性に優れた発泡体は、車輌用、建材
用、保温保冷材用、各種包装材用、家具雑貨用等
現代の需要に適合した製品であるだけに、本発明
ACの意義は大きい。
以下実施例について本発明をさらに説明する。
実施例 １
水400ml中にヒドラゾジカルボンアミド118ｇと
臭化ナトリウム1.5ｇを投入し、撹拌しながら塩
素22.1を約５時間かけて吹込んだ。尚、反応温
度は30〜35℃に調整した。反応終了後、生成した
黄色結晶のACを別し、水洗乾燥して113ｇ（純
度99.7％，収率97.4％）を得た。このAC原料の
平均面積粒径は11.2μで、Ｘ線回折角強度比I1／I2
は1.56（第２図）、分解温度は196.5℃であつた。
このAC原料20ｇを水100mlに投入し、76〜81℃
で２時間加熱処理して急冷し、別して19ｇ（純
度99.8％、収率95.5％）の本発明ACを得た。こ
のものの平均面積粒径は11.8μで、Ｘ線回折角強
度比I1／I2は2.29（第１図）、分解温度は197.8℃で
あつた。
上記の如くして得られた本発明ACを用い、以
下のように発泡体を作つた。即ち、メルトインデ
クツス1.0の高圧法ポリエチレン100重量部に、架
橋剤ジクミールパーオキサイド0.85重量部、架橋
助剤トリメチロールプロパントリアクリレート
0.45重量部、本発明AC16.5重量部、発泡助剤酸
化亜鉛0.05重量部を加え、105〜110℃に加熱した
ロールで均一に混練し、厚さ0.85mmのシートをま
ず作り、同シートを200×200mmに載断し、そのシ
ート４枚を200×200×２mmの密閉金型に入れ、
120℃で10分間20Kg／cm2の圧力をかけ成形した。
冷却後金型より取出し、中央部より50×50mm切り
取り発泡用試料とした。この試料を熱風循還式乾
燥炉に入れ、220℃で２分間加熱して発泡させた。
得られた発泡体の表面は極めて平滑美麗で、密度
は33.8ｇ／（29倍発泡）であつた。
この発泡体より、第３図に示すような方法でサ
ンプルを切り出し、厚み方向のスライス面につい
て、縦及び横方向の５mmの長さを横切る気泡数を
顕微鏡で読みとり、５mmを気泡数で割つて気泡径
を求めた。かゝる方法で、Ａ，Ｂ，C3個所を測
定しその算術平均をもつて、平均気泡径〔〕と
した。又、上述の気泡径測定中観測された気泡の
中で最も大きい気泡径を測定して最大気泡径
〔dmax〕とし、〔dmax−〕をもつて気泡均一
性とした。更に、発泡体の実用的な特性値とし
て、単位長さ当りの気泡数、単位面積当りの気泡
数、単位体積当りの気泡数を検討した。即ち、５
mmを横切つた気泡数を２倍して１cm当りの気泡数
とし、これを２乗して１cm2当りの気泡数、更に３
乗したものを１cm3当りの気泡数とした。これらの
結果は一括して第１表に示した。
実施例 ２〜４
実施例１で得たAC原料を使用し、処理条件は
第１表により、他は実施例１と同じ方法で本発明
のACを得た。又、実施例１と同じ方法で発泡体
を得たが、いづれも外観は平滑美麗で内部は均一
微細の独立気泡であつた。
その測定結果を第１表に示す。
比較例 １
実施例１で作られたAC原料（Ｘ線回折角強度
I1／I21.56平均面積粒径11.2μ）を用い、実施例１
と同じ方法で発泡体を作つた。得られた発泡体の
表面は粗雑で、気泡径は大きく不均一であつた。
その測定結果は第１表に示した。
比較例 ２〜４
市販されている代表的な３社のACについて、
実施例１と同じ方法で発泡体を作り、得られた発
泡体を検査したが、いづれも本発明ACより悪い
結果を示した。
The present invention relates to azodicarbonamide that enables highly foamed products having a uniform and fine closed cell structure. That is, the diffraction angle intensity I 1 of the X-ray diffraction angle 2θ = 28.9°
and the diffraction angle intensity I 2 at 2θ=15.8°, the intensity ratio I 1 /I 2 is
This invention relates to a hitherto unknown azodicarbonamide for blowing agents, which has a particle diameter of 1.7 to 4.0 and a particle size corresponding to 50% of the cumulative area diameter curve of 6 to 15μ. In recent years, the method of obtaining foams by blending foaming agents with various natural or synthetic resins has become widespread, and these foams can be used, for example, as insulation materials, cushion materials, packaging materials, sound insulation materials, packing materials, flotation materials, It has many uses such as electrical insulation materials, structural materials, and household goods.
However, the physical properties of foams such as cushioning properties, elasticity, heat insulation properties, soundproofing properties, and surface smoothness are closely related to the cell structure of the foam, especially in foams with high expansion ratios. There has been a strong demand for uniformity and fineness. Conventionally, in order to meet such demands,
Various proposals have been made. For example, special public relations
Modification of resins such as 3876 and Tokuko Sho 52-39662, addition of bubble control agents and nucleating agents, and even Tokuko Sho 52-39662.
Although cross-linking aids such as No. 54-25972 have been added, the blowing agent used has not been carefully examined, so the result is not always fully satisfactory. There are many thermally decomposable blowing agents used for such purposes, but the decomposition behavior can be adjusted arbitrarily with an auxiliary agent, the amount of cracked gas is large, and the main component of the cracked gas is nitrogen, which is preferable for forming closed cells. , azodicarbonamide (hereinafter referred to as
(sometimes abbreviated as AC) is the mainstream. However, in order to make a foam with a high expansion ratio (low density), a large amount of blowing agent is used, so the pressure of the decomposed gas during foaming is large, causing the bubbles in the foam to become coarse and uneven. I couldn't escape it. As a proposal for a blowing agent to form uniform and fine bubbles, for example,
There are 53956. That is, as a blowing agent, the average particle size (note: the median diameter determined from the particle size distribution on a weight basis) is 10 to 30μ, and particles exceeding 5μ are
If a chemically decomposed foaming agent containing at least % by weight is used, a foam with small cell diameters can be obtained. In other words, it is possible to obtain a blowing agent that forms fine, uniform cells by pulverization and classification, regardless of the manufacturing conditions of the blowing agent, but this proposal is based on the manufacturing conditions of the blowing agent and its The proposal ignored the crystal structure and was extremely inadequate. As a result of intensive research, the present inventors aimed to produce a foaming agent for high expansion ratio foams in which it is extremely difficult to form a uniform, fine, closed-cell structure.
There is an AC with previously unknown X-ray diffraction properties,
It can be manufactured and has this X-ray diffraction property.
The present invention was based on the discovery that AC enables the formation of a foam with a uniform and fine closed-cell structure, and can improve the various defects of conventional AC. Therefore, an object of the present invention is to provide an AC which can be used for resin foaming, etc., and which overcomes the above-mentioned defects. The objects and advantages of the present invention will become more apparent from the following description. Conventional ACs are made by oxidizing hydrazodicarbonamide with various oxidizing agents. Oxidizing agents include chlorine gas, chlorine compounds such as sodium hypochlorite and sodium perchlorate, nitrogen compounds such as ammonium nitrate and nitrogen oxide, and dichromic acids such as potassium dichromate and sodium dichromate. Compounds, peroxides such as hydrogen peroxide, etc. are used. The particle size corresponding to 50% of the cumulative area diameter curve (hereinafter sometimes abbreviated as "average area particle size") produced by such a known method is 5 to 15μ.
Conventional azodicarbonamide has an X-ray diffraction angle of 2θ
Diffraction angular intensity I 1 at =28.9° and diffraction angular intensity I 2 at 2θ = 15.8°
intensity ratio I 1 /I 2 (hereinafter referred to as "X-ray diffraction angle intensity ratio I 1 /
I 2 ) is less than 1.7 or more than 4.0, and such AC cannot provide the excellent effects of the AC of the present invention. The AC of the present invention has an X-ray diffraction angle intensity ratio I 1 /I 2 of 1.7 to
4.0 and the average area particle size should be 6 to 15μ, but the X-ray diffraction angle intensity ratio I 1 /I 2 is preferably 1.8 to
3.8, particularly preferably from 1.9 to 3.5, and the average area particle size is preferably from 7 to 14μ, particularly preferably from 8 to 3.5.
It is 13μ. If the X-ray diffraction angle intensity ratio I 1 / I 2 is too small, less than 1.7, there are many amorphous crystal structures with undeveloped 101 planes, and they do not form uniform, fine closed cells. . On the other hand, if it exceeds 4.0, the crystals will become more regularized and the size of the crystals will become uniform, but this will lead to a decrease in the yield in terms of the manufacturing process, so it is not practical and undesirable. On the other hand, if the average area particle size of AC is too small, such as 5μ or less, the decomposition rate is too fast and the resin is likely to decompose during kneading and molding.Also, the resin expands rapidly in the foaming furnace and the cell size The foam becomes coarse and gas escapes from the surface of the foam, causing rough skin, which is undesirable. In addition, if the size is too large (15μ or more), the width of the particle size is large, which causes uneven foaming in the foam and does not result in uniform bubbles, and excessive coarse particles remain undecomposed and the foam does not finish white. It is not desirable to have it. The X-ray diffraction angle intensity ratio I 1 /I 2 of the AC of the present invention is
This will be explained in more detail with reference to the drawings. Figure 1 shows the present invention.
This is an example of an X-ray diffraction diagram of AC.The X-ray diffraction measurement is performed using an automatic recording powder Diffraction device (manufactured by JEOL Ltd. [model JDX-8SH]), the radiation source is Cu-
(Kd line, output 30KV, 14mA). The horizontal axis in Figure 1 represents the diffraction angle 2θ (unit: degrees), and the vertical axis represents the diffraction intensity (unit: cps, counts per second).
The diffraction intensity at 2θ=28.9° is indicated by I 1 in the figure, and the diffraction intensity at 2θ=15.8° is indicated by I 2 , and the X-ray diffraction intensity ratio referred to in the present invention is calculated as I 1 /I 2 . Further, the method for measuring the particle size of AC in the present invention will be explained in detail below. Although various instruments for measuring particle size or particle size have been developed, the present inventors developed a light transmission particle size distribution measuring instrument (manufactured by Seishin Enterprise Co., Ltd. [model: SK type]) was used. That is, it is a particle size corresponding to 50% of the cumulative curve of area diameter shown by this light transmission type particle size distribution analyzer. (This value basically matches the average particle diameter of a specific surface area meter, so the value measured by that device may be used.) This cumulative area diameter curve can be converted into a weight cumulative curve, but if the particles are spherical, Alternatively, it is fine if it is close to a cube, but if it is rectangular parallelepiped or needle-shaped, it is difficult to convert it into weight. For example, when ACs with average area particle diameters of 10μ, 6μ, and 3μ are converted to average particle diameters based on weight, they are 22μ, 22μ, and 3μ, respectively.
It became 11μ. Therefore, the present inventors adopted the areal diameter as a measure of particle size that provides a clearer criterion. A special AC like the one of the present invention can be manufactured, for example, by the following method. That is, AC produced by a conventionally known method is put into a medium that is difficult to decompose, and heated at 45 to 100°C for 4 hours to 15 minutes while stirring.
The AC of the present invention can be obtained by heating for a minute and then adjusting the crystal form while cooling. The heat treatment may be performed after the oxidation reaction of hydrazodicarbonamide is completed, or the temperature may be gradually increased at the end of the reaction. If the medium used in this method is alkaline
Although it is important that the acidity is weakly acidic because it decomposes AC, it is practical to use water from an economical or pollution standpoint. In addition, at this time, chemicals are added for the purpose of modifying or improving the quality of AC, such as adjusting the decomposition temperature of AC, increasing the amount of gas generated, and preventing caking. There is nothing to prevent it from being attached to. in the medium
The slurry concentration of AC is 5 to 40% by weight, preferably 15 to 30% by weight, considering the capacity of the stirrer and productivity. Furthermore, if the heat treatment temperature is too low, crystallization will not proceed even if the time is increased, whereas if it is too high, AC will decompose to produce hydrazodicarbonamide, which will reduce the yield, which is not preferable. Heating temperature is 45~
The temperature is 100°C, preferably 55-100°C, and the treatment time is 4 hours to 10 minutes, preferably 3 hours to 30 minutes. The cooling method after the heat treatment may be rapid cooling or slow cooling depending on the particle size to be obtained. Incidentally, this does not preclude pulverization and classification as necessary. Although the special AC of the present invention can be manufactured by the method described above, it is not necessarily necessary and is not particularly limited. The resin with which the foam is produced by blending AC as a blowing agent includes various natural and synthetic resins, copolymers or blends thereof, and is not particularly limited. For example, polyolefins such as polyethylene and polypropylene, polyamides such as nylon, thermoplastic resins such as polyester, rubber, cellulose, and polyvinyl, and thermoplastic resins such as urea, phenol, melamine, and epoxy. With hardening resin,
It can be used for anything that can be expanded using gas generated by decomposition of a blowing agent, but it is preferably used for polyolefin-based and polyvinyl-based resins. The above resins include plasticizers, stabilizers, cell regulators, crosslinking agents, crosslinking aids, lubricants, fillers, colorants, ultraviolet absorbers, antistatic agents, surfactants, and foaming aids, as necessary. It may also contain additives such as. Since the decomposition temperature of the AC of the present invention is similar to that of conventionally known AC, no special consideration is required when using it, but a decomposition accelerator may be used if necessary. In foams the use of crosslinking aids is preferred. The amount of the AC of the present invention to be blended with the resin may be determined as appropriate depending on the desired expansion ratio. The foaming method to which the present invention is applied is, for example, to obtain a foamed composition by kneading and extrusion molding using an extrusion molding machine or the like, and then heating it by hot air, infrared lamp irradiation, induction heating using high frequency current, etc. under normal pressure. It can be applied to methods of making foam by decomposing a foaming agent. As described above, the AC of the present invention can be easily produced industrially, and a foam having uniform and fine closed cells can be easily and reliably produced. In particular, foams with excellent insulation and cushioning properties are products that meet modern demands such as for vehicles, building materials, heat and cold insulation materials, various packaging materials, and furniture miscellaneous goods.
AC has great significance. The present invention will be further explained below with reference to Examples. Example 1 118 g of hydrazodicarbonamide and 1.5 g of sodium bromide were put into 400 ml of water, and 22.1 g of chlorine was blown into the mixture over about 5 hours while stirring. Note that the reaction temperature was adjusted to 30 to 35°C. After the reaction was completed, the produced yellow crystals AC were separated, washed with water and dried to obtain 113 g (purity 99.7%, yield 97.4%). The average area particle size of this AC raw material is 11.2μ, and the X-ray diffraction angle intensity ratio I 1 /I 2
was 1.56 (Figure 2), and the decomposition temperature was 196.5°C. Pour 20g of this AC raw material into 100ml of water and heat to 76-81℃.
The mixture was heat-treated for 2 hours, rapidly cooled, and separated to obtain 19 g (purity 99.8%, yield 95.5%) of the AC of the present invention. The average area particle size of this product was 11.8μ, the X-ray diffraction angle intensity ratio I 1 /I 2 was 2.29 (Figure 1), and the decomposition temperature was 197.8°C. Using the AC of the present invention obtained as described above, a foam was made as follows. That is, 100 parts by weight of high-pressure polyethylene with a melt index of 1.0, 0.85 parts by weight of dicumyl peroxide as a crosslinking agent, and trimethylolpropane triacrylate as a crosslinking agent.
Add 0.45 parts by weight, 16.5 parts by weight of AC of the present invention, and 0.05 parts by weight of zinc oxide as a foaming aid, and knead them uniformly with a roll heated to 105 to 110°C to first make a sheet with a thickness of 0.85 mm. Cut to 200 x 200 mm, put the four sheets into a 200 x 200 x 2 mm sealed mold,
Molding was carried out at 120°C for 10 minutes by applying a pressure of 20 kg/cm 2 .
After cooling, it was taken out from the mold and a 50 x 50 mm cut from the center was used as a foaming sample. This sample was placed in a hot air circulation drying oven and heated at 220°C for 2 minutes to foam.
The surface of the obtained foam was extremely smooth and beautiful, and the density was 33.8 g/(29 times foamed). A sample was cut out from this foam using the method shown in Figure 3, and on the sliced surface in the thickness direction, the number of bubbles across a length of 5 mm in the vertical and horizontal directions was read using a microscope, and 5 mm was divided by the number of bubbles. The bubble diameter was determined. Using this method, measurements were taken at three locations A, B, and C, and the arithmetic mean of the measurements was taken as the average bubble diameter. In addition, the largest bubble diameter among the bubbles observed during the above-mentioned bubble diameter measurement was determined as the maximum bubble diameter [dmax], and [dmax-] was defined as the bubble uniformity. Furthermore, as practical characteristic values of the foam, the number of bubbles per unit length, the number of bubbles per unit area, and the number of bubbles per unit volume were investigated. That is, 5
Double the number of bubbles that cross mm to get the number of bubbles per cm, then square this to get the number of bubbles per cm2 , and then 3
The product multiplied by this value was taken as the number of bubbles per 1 cm3 . These results are summarized in Table 1. Examples 2 to 4 AC of the present invention was obtained using the AC raw material obtained in Example 1, using the treatment conditions as shown in Table 1, and in the same manner as in Example 1 except for the treatment conditions. Further, foams were obtained in the same manner as in Example 1, and each foam had a smooth and beautiful appearance, and the inside had uniform, fine, closed cells. The measurement results are shown in Table 1. Comparative Example 1 AC raw material made in Example 1 (X-ray diffraction angular intensity
Example 1
The foam was made using the same method. The surface of the obtained foam was rough, and the cell diameters were large and non-uniform.
The measurement results are shown in Table 1. Comparative Examples 2 to 4 Regarding ACs from three representative companies on the market,
Foams were made in the same manner as in Example 1, and the resulting foams were tested, but all showed worse results than the AC of the present invention.
【表】【table】
【表】【table】
【図面の簡単な説明】[Brief explanation of the drawing]
第１図は本発明ACのＸ線回折図の一例、第２
図は従来公知の製造方式によるACのＸ線回折図
の一例、第３図は発泡体の気泡径等測定の位置を
示したものである。
Ｘ……縦方向、Ｙ……横方向、Ｚ……厚み方
向、Ａ，Ｂ，Ｃ……サンプル。
Figure 1 is an example of the X-ray diffraction diagram of the AC of the present invention;
The figure shows an example of an X-ray diffraction diagram of an AC produced by a conventionally known manufacturing method, and FIG. 3 shows the positions for measuring the bubble diameter, etc. of the foam. X...Longitudinal direction, Y...Horizontal direction, Z...Thickness direction, A, B, C...Sample.