【発明の詳細な説明】[Detailed description of the invention]
本発明は難燃性塩素含有樹脂組成物につき、塩
素含有樹脂に、直径10ミクロン以下のものが90％
以上を占める微粉末メラミンを３〜60重量部配合
してなる加工性の改善された塩素含有樹脂組成物
に関するものである。
今日、合成樹脂はその安価、良好な加工性によ
り金属、コンクリート、木材、紙等の旧来の素材
に代り、種々の形で利用され社会のあらゆる分野
に広く入り込んでいる。建築分野に於てもこの傾
向は著しく、壁、床、配線、配管、家具、雑貨類
に至るまで合成樹脂の使用が行われている。しか
しこのような現状の持つ危険性として、火炎時に
これら合成樹脂製品の易燃性が挙られる。このた
め合成樹脂に難燃性や不燃性を与える試みが各方
面からなされてきた。
一般に塩素含有樹脂は比較的難燃性を有してい
るため、従来一部の分野を除いて特に難燃性を強
化する試みは少なかつた。一般に塩素含有樹脂製
品は軟化点が低く、またその引火点は比較的高い
が、火炎に暴露されゝば軟化し黒煙を上げて燃焼
することは建築関係者の各種試験でも発表されて
いる。特に可塑剤を加えた軟質製品に於ては高温
にてフラツシユオーバーし自己発炎して火災を拡
大する。塩素含有樹脂を少しでも難燃性を向上し
延焼性を減少し、発煙を少くすることが建築材
料、家具等に使用するに際し重要となり、近時
種々の試みがなされている。
従来塩素含有樹脂に用いられる難燃剤として
は、三酸化アンチモンが良く知られている。しか
し樹脂の組成にも依るが、通常５〜10％、難燃化
を特に要望する場合には10％以上もの添加量を必
要とするが、三酸化アンチモンは高価であり加工
品の経済性を著しく悪くさせる欠点がある。そこ
で安価に入手し得るカルシウムやシリカを始めと
する種々の金属酸化物及び水酸化物等の無機充填
剤を塩素含有樹脂に添加する方法も提案されてい
る。しかしこれら無機物は大量に添加しなければ
効果の少いものが殆んどであり、しかも発煙量を
抑えるのが目的で難燃化力そのものは弱いもので
ある。更に得られる樹脂加工品の重量の著しい増
加及び樹脂本来の機械的性質等を損う点に於て使
用に限界がある。
この他、有機難燃剤としては塩素化パラフイン
のように難燃力が弱いため大量に添加するか他の
無機難燃剤を併用する必要があつたり、リン酸エ
ステルのように自身高価であるうえに、熱安定性
を悪化させるため熱安定剤を余分に添加する必要
がある等の欠点を有する。更にこれら液状の可塑
剤系難燃剤は塩素含有樹脂本来の溶融流動性を大
きく変化させるうえ、必ずしも安価なものではな
い。本発明者らは塩素含有樹脂に充分な難燃性を
与え、かつ得られる樹脂組成物の比重、色調、機
械的性質、例えば引張強度、伸度等損わず、しか
も価格的に安価な加工性の優れた添加剤を見出し
本発明を完成するに至つた。
即ち本発明は、塩素含有樹脂に難燃剤として微
粉末メラミンを配合してなる難燃性塩素含有樹脂
組成物に関するものである。メラミン樹脂の原料
として比較的安価に製造されているところのメラ
ミンはトリアジン系含窒素系化合物として難燃性
を有することは知られているが特許昭和38年第
6376号公告公報、特許昭和39年第14513号公告公
報に塩化ビニル系樹脂に含鉄アスベストを配合す
る際の着色防止剤として微量添加する例があり、
また特許昭和50年第46749号公開公報には、メラ
ミンを重合体中に添加する記載があるが、ケト基
含有化合物と併用して酸化劣化防止効果を対象と
したもので、本発明の難燃効果を対象としたもの
と異なる。
また特許昭和47年第1584号公開公報には熱可塑
剤樹脂にメラミンを添加して耐焔性を付与したも
のについての記載があるが、本特許はメラミンが
熱可塑性樹脂に較べて極めて過剰の添加量のもの
で、ポリ塩化ビニル樹脂系に添加した場合はかゝ
る185〜850重量部も添加した系では樹脂とメラミ
ンとの相溶性が十分でないためブリード、アウト
がひどく、また機械的な脆化が起り易く工業的に
利用できるものとは考えられない。本発明に於
て、微粉末メラミンと称するものは、従来メラミ
ン樹脂の原料として市販されている粒子径20〜
100ミクロンの通常メラミン（以下通常メラミン
と略称）と異なり、粒径10ミクロン以下が90％を
占めるものもしくはその表面処理物を指す。通常
メラミンの機械的粉砕によつて微粉末メラミンを
得るのは困難なため従来かゝる微粉末メラミンが
樹脂加工分野等で検討されることがなかつた。本
発明で用いる微粉末メラミンとしては、メラミン
の結晶析出工程で10ミクロン以下の微粉末が直接
得られる製造法で造られたもの、気相法により直
接合成したものを風篩工程で組合せたものが好ま
しく、かゝる微粉末メラミンは近時安価に入手で
きるようになつた。かゝる微粉末メラミンと塩素
含有樹脂との配合物を成形加工して得られる製品
は、比較的少量の微粉末メラミンの使用にも拘ら
ず優れた難燃性を示すことが判明した。通常のメ
ラミンを用いた場合にもある程度の難燃性は認め
られるが、得られる成形物は塩素含有樹脂成形物
本来有する機械的強靭性が大きく損われる上に、
成形品表面肌が悪いという実用上の大きな欠点を
有し、また樹脂中での均質分散が不十分であつ
た。これらの事実よりメラミンを塩素含有樹脂に
比較的大量に添加するということ自体が実用性の
ないことゝ考えられて来たことが説明される。
本発明者らは、通常メラミンとは異なり粒径10
ミクロン以下が90％を占める微粉末メラミンを持
つ興味ある性質の研究より、塩素含有樹脂への配
合によりメラミンがかゝる工業的有用性を有する
ことを発見するに至つた。しかし、粒径が10ミク
ロン以下のものが90％以下のものを用いた場合に
は上記の通常メラミンについて示したと同様な挙
動を示し微粉末メラミンを用いた場合に較べてそ
の有用性は極めて低かつた。
また一般に無機系充填剤を塩素含有樹脂に配合
した場合、見掛溶融粘度の上昇を伴い、成形加工
性の悪化をもたらすおそれがある。しかるに微粉
末メラミンを用いた場合、むしろ融融粘度の低下
が見られ、成形加工を容易にするという予期せざ
る効果が認められ工業的な実用性が極めて高いこ
とが判明した。
更に予期せざる効果として塩素含有樹脂の加工
時に不可避的に生じる黄変着色が、微粉末メラミ
ンを用いた場合、著しく減少され通常の熱安定剤
や青み付け剤の使用量を減ずることが出来ること
を見出した。アスベスト等の天然鉱物は塩素含有
樹脂を着色させる不純物を含むため通常メラミン
を添加すると着色が抑えられるという事実は知ら
れているが、かゝる鉱物を含まない塩素含有樹脂
の着色防止力は通常メラミンに於ては十分なもの
とは認められない。しかるに微粉末メラミン配合
による塩素含有樹脂の著しく良好な色調は全く予
期せざる効果である。これは一般の難燃剤の添加
の場合塩素含有樹脂成形品が無視し得ない程度に
着色することが多いのに反し、微粉末メラミンの
使用によりむしろ難燃剤を添加しない状態よりも
着色が減少するという極めて好ましい現象である
ことを意味する。
以上述べた如く、微粉末メラミンと塩素含有樹
脂よりなる組成物は、単に比較的安価で難燃性を
有するのみでなく、得られる加工製品の着色がな
くかつ塩素含有樹脂本来の機械的性質を損わない
うえ、優れた成形性を示すという、工業的に有用
な性質を兼備する点に於て、従来の難燃性塩素含
有樹脂組成物から大きく改善されたものと考えら
れる。
本発明で塩素含有樹脂とはポリ塩化ビニル、塩
化ビニリデン、塩素化ポリエチレン、塩化ビニル
と他の不飽和単量体との共重量体、または、これ
らの樹脂を主体とする他の樹脂とのブレンド物な
どである。
また本発明に於て、樹脂に対する微粉末メラミ
ンの添加量は樹脂100重量部（以下単に部と略
称）に対し0.5部以上であれば良いが好ましくは
３〜60部が良い。添加量が0.5部以下の場合には
着色防止効果は認められるが、難燃効果は認めら
れず、60部以上の添加した場合は機械的性質の低
下が見られ、経済性も劣り好ましくない。
本発明に於ては、塩素含有樹脂に微粉末メラミ
ンの他に添加剤として、可塑剤、安定剤、滑剤、
充填剤、顔料、染料、架橋剤等を必要に応じて添
加することも可能であり、これらの添加剤によつ
て本発明の効果が損われることはない。
以下に実施例を用いて本発明を更に詳細に説明
する。
実施例 １〜３
重合度1050のポリ塩化ビニル100部に対してフ
タール酸ジオクチル50部ステアリン酸カルシウム
1.5部、ステアリン酸亜鉛0.5部、エポキシ化大豆
油20部からなる組成物に微粉末メラミン（日産化
学工業製10ミクロン以下90％含有）５〜50部を加
え、150℃３分間ロール混練して得られたシート
を170℃にてプレス成形して試験片用シートを得
た。このシートを用いて以下の試験を行つた。結
果を表１に示す。
引張試験：JIS Ｋ−6723に準じて行つた。
色調試験：１mm厚さのプレスシートを用い、シー
トの上に黒板を置きスガ試験機製測
色々差計AUD−CH−２型により、ハ
ンターの白度Ｗで示した。
Ｗが100に近い程白いことを表わす。
熱安定性試験：１mm厚さのシートを３cm×３cmに
切り、170℃のギヤーオーブン中
に放置し、15分毎に着色を観察
し、シートが黄味を帯びる迄の時
間及び黒化時間を調べた。
難燃性試験：米国UL−94方法に準ずる。
長さ５インチ、幅1/2インチ、厚み1/16、1/8、
1/4インチの試験片を作成する。試験片を垂直に
保持し、その下端にバーナーの火炎を10秒間あ
て、火炎を取り除いてから消火するまでの時間を
計測し、消火したらすぐ２回目の接炎を10秒間行
ない、再び消火するまでの時間を測定する。試験
片の下部に綿を置き試験片からの溶融滴下物によ
つて綿が発火するか否かも観察する。
以上の操作を５本の試験片について実施し、次
の基準に従つて難燃性のランク付をした。
The present invention relates to a flame-retardant chlorine-containing resin composition in which 90% of the chlorine-containing resin has a diameter of 10 microns or less.
This invention relates to a chlorine-containing resin composition with improved processability, which contains 3 to 60 parts by weight of finely powdered melamine. Nowadays, synthetic resins are used in various forms in place of traditional materials such as metal, concrete, wood, and paper due to their low cost and good workability, and are widely used in all fields of society. This trend is also noticeable in the field of architecture, where synthetic resins are used for walls, floors, wiring, piping, furniture, and miscellaneous goods. However, one of the dangers of this current situation is the flammability of these synthetic resin products when exposed to flames. For this reason, attempts have been made from various fields to impart flame retardancy and noncombustibility to synthetic resins. Since chlorine-containing resins generally have relatively flame retardancy, there have been few attempts to particularly enhance the flame retardancy except in some fields. In general, chlorine-containing resin products have a low softening point and a relatively high flash point, but various tests conducted by construction personnel have shown that if exposed to flame, they will soften and burn with black smoke. In particular, soft products containing plasticizers will flash over at high temperatures, causing self-ignition and spreading the fire. It has become important to improve the flame retardancy of chlorine-containing resins, reduce fire spread, and reduce smoke generation when used in building materials, furniture, etc., and various attempts have been made in recent years. Antimony trioxide is well known as a flame retardant conventionally used for chlorine-containing resins. However, depending on the composition of the resin, it is usually necessary to add 5 to 10%, and if flame retardance is particularly desired, 10% or more is required, but antimony trioxide is expensive and reduces the economic efficiency of processed products. There are drawbacks that make it significantly worse. Therefore, methods have also been proposed in which inorganic fillers such as various metal oxides and hydroxides, including calcium and silica, which are available at low cost, are added to chlorine-containing resins. However, most of these inorganic substances have little effect unless they are added in large quantities, and their flame retardant power itself is weak since the purpose is to suppress the amount of smoke generated. Furthermore, there is a limit to its use in that it significantly increases the weight of the resulting resin processed product and impairs the inherent mechanical properties of the resin. In addition, organic flame retardants such as chlorinated paraffin have weak flame retardant power and must be added in large quantities or used in combination with other inorganic flame retardants, and phosphate esters are expensive themselves and However, it has disadvantages such as the need to add an extra heat stabilizer to deteriorate the heat stability. Furthermore, these liquid plasticizer-based flame retardants greatly change the inherent melt fluidity of the chlorine-containing resin, and are not necessarily inexpensive. The present inventors have proposed a process that imparts sufficient flame retardancy to chlorine-containing resins, does not impair the specific gravity, color tone, mechanical properties, such as tensile strength, elongation, etc. of the resulting resin composition, and is inexpensive. They discovered an additive with excellent properties and completed the present invention. That is, the present invention relates to a flame-retardant chlorine-containing resin composition comprising a chlorine-containing resin mixed with finely powdered melamine as a flame retardant. Melamine, which is manufactured relatively cheaply as a raw material for melamine resin, is known to have flame retardant properties as a triazine-based nitrogen-containing compound, but it was patented in 1962.
There is an example in Publication No. 6376 and Publication No. 14513 of 1968 of adding a small amount as a coloring preventive agent when blending iron-containing asbestos into vinyl chloride resin.
In addition, Patent Publication No. 46749 of 1975 describes adding melamine to a polymer, but this is intended for the effect of preventing oxidative deterioration when used in combination with a keto group-containing compound. This is different from the one that targets effects. In addition, Patent Publication No. 1584 of 1972 describes a product in which melamine is added to a thermoplastic resin to impart flame resistance, but this patent states that melamine is extremely excessive compared to the thermoplastic resin. When added to a polyvinyl chloride resin system, the compatibility between the resin and melamine is insufficient, resulting in severe bleeding and mechanical problems. It is not considered to be suitable for industrial use as it is prone to embrittlement. In the present invention, what is referred to as fine powder melamine has a particle size of 20 to
Unlike normal melamine (hereinafter referred to as normal melamine), which has a particle diameter of 100 microns, 90% of it is 10 microns or less, or it refers to a surface-treated product. Since it is usually difficult to obtain fine powder melamine by mechanically crushing melamine, such fine powder melamine has not been considered in the field of resin processing. The fine powder melamine used in the present invention includes those made by a manufacturing method that directly obtains fine powder of 10 microns or less in the melamine crystal precipitation process, and those synthesized directly by a gas phase method and combined in an air sieving process. is preferred, and such finely powdered melamine has recently become available at low cost. It has been found that a product obtained by molding a blend of such fine powder melamine and a chlorine-containing resin exhibits excellent flame retardancy despite the use of a relatively small amount of fine powder melamine. Although a certain degree of flame retardancy is observed when ordinary melamine is used, the resulting molded product suffers from a significant loss of mechanical toughness, which is inherent to chlorine-containing resin molded products.
The molded product had a major practical drawback of poor surface texture, and homogeneous dispersion in the resin was insufficient. These facts explain why it has been considered impractical to add relatively large amounts of melamine to chlorine-containing resins. The present inventors have discovered that unlike normal melamine, the particle size is 10
Through research into the interesting properties of fine powder melamine, which has a particle size of 90% or less, it has been discovered that melamine has such industrial utility when incorporated into chlorine-containing resins. However, if 90% or less of particles with a particle size of 10 microns or less are used, the behavior is similar to that shown above for normal melamine, and its usefulness is extremely low compared to when fine powder melamine is used. It was. Furthermore, in general, when an inorganic filler is blended into a chlorine-containing resin, the apparent melt viscosity increases, which may lead to deterioration in moldability. However, when finely powdered melamine was used, the melt viscosity was actually lowered, and the unexpected effect of facilitating molding was observed, proving that it has extremely high industrial practicality. Furthermore, an unexpected effect is that the yellowing coloration that inevitably occurs during the processing of chlorine-containing resins is significantly reduced when finely powdered melamine is used, making it possible to reduce the amount of conventional heat stabilizers and blue tinting agents used. I found out. It is known that natural minerals such as asbestos contain impurities that color chlorine-containing resins, so adding melamine usually suppresses the coloration, but chlorine-containing resins that do not contain such minerals usually have no coloration prevention ability Melamine is not recognized as being sufficient. However, the significantly better color tone of the chlorine-containing resin by incorporating finely powdered melamine is a completely unexpected effect. This is because when adding a general flame retardant, chlorine-containing resin molded products are often colored to a non-negligible extent, but by using fine powder melamine, the coloring is actually reduced compared to when no flame retardant is added. This means that this is an extremely favorable phenomenon. As mentioned above, a composition made of finely powdered melamine and a chlorine-containing resin is not only relatively inexpensive and flame-retardant, but also eliminates the coloring of the resulting processed product and maintains the mechanical properties inherent to the chlorine-containing resin. It is considered to be a great improvement over conventional flame-retardant chlorine-containing resin compositions in that it has industrially useful properties such as not causing any damage and exhibiting excellent moldability. In the present invention, chlorine-containing resins include polyvinyl chloride, vinylidene chloride, chlorinated polyethylene, coweights of vinyl chloride and other unsaturated monomers, or blends of these resins with other resins. Things, etc. Further, in the present invention, the amount of finely powdered melamine added to the resin may be 0.5 parts or more per 100 parts by weight of the resin (hereinafter simply referred to as "parts"), but preferably 3 to 60 parts. When the amount added is 0.5 parts or less, a discoloration prevention effect is observed, but no flame retardant effect is observed, and when it is added in an amount of 60 parts or more, a decrease in mechanical properties is observed and the economical efficiency is also poor, which is not preferable. In the present invention, in addition to finely powdered melamine, the chlorine-containing resin contains additives such as plasticizers, stabilizers, lubricants,
It is also possible to add fillers, pigments, dyes, crosslinking agents, etc. as necessary, and the effects of the present invention are not impaired by these additives. The present invention will be explained in more detail below using Examples. Examples 1 to 3 50 parts of dioctyl phthalate and calcium stearate per 100 parts of polyvinyl chloride with a degree of polymerization of 1050
To a composition consisting of 1.5 parts of zinc stearate, 0.5 parts of zinc stearate, and 20 parts of epoxidized soybean oil, 5 to 50 parts of finely powdered melamine (containing 90% of 10 microns or less, manufactured by Nissan Chemical Industries) was added, and the mixture was roll-kneaded at 150°C for 3 minutes. The obtained sheet was press-molded at 170°C to obtain a test piece sheet. The following tests were conducted using this sheet. The results are shown in Table 1. Tensile test: Conducted according to JIS K-6723. Color tone test: Using a press sheet with a thickness of 1 mm, a blackboard was placed on the sheet and the whiteness was measured using Hunter's whiteness W using a multimeter AUD-CH-2 manufactured by Suga Test Instruments. The closer W is to 100, the whiter it is. Thermal stability test: Cut a 1mm thick sheet into 3cm x 3cm pieces, leave it in a gear oven at 170℃, observe the coloration every 15 minutes, and measure the time until the sheet turns yellowish and the time it takes to blacken. Examined. Flame retardancy test: Based on the US UL-94 method. Length 5 inches, width 1/2 inch, thickness 1/16, 1/8,
Create a 1/4 inch specimen. Hold the test piece vertically and apply the flame of a burner to the lower end for 10 seconds, measure the time from when the flame is removed until the flame is extinguished, and immediately after the flame is extinguished, apply a second flame for 10 seconds until the flame is extinguished again. Measure the time. Place cotton under the test piece and observe whether the cotton ignites due to the molten drippings from the test piece. The above operations were performed on five test pieces, and the flame retardance was ranked according to the following criteria.
【表】
見掛溶融粘度：高化式フローテスターを用いて１
mm径のノズル、160℃、荷重100Kg
で測定した。
比較例 １〜３
実施例１〜３の微粉末メラミンの代りに通常メ
ラミン（粒径20〜110ミクロンが95％以上のも
の）を５〜50部添加したもの及びメラミンを全く
添加していないもので行つた結果を表１に示す。[Table] Apparent melt viscosity: 1 using Koka type flow tester
mm diameter nozzle, 160℃, load 100Kg
It was measured with Comparative Examples 1 to 3 Examples 1 to 3 in which 5 to 50 parts of normal melamine (95% or more of particle size is 20 to 110 microns) were added instead of the finely powdered melamine of Examples 1 to 3, and those in which no melamine was added at all. The results are shown in Table 1.
【表】
本実施例に見られるごとくポリ塩化ビニル樹脂
に粒子径10ミクロン以下90％以上の微粉末メラミ
ンを添加した系は、20〜110ミクロンの粒子径の
通常メラミンを添加した比較例と較べると機械的
強度の改善，白度の向上，熱安定性および難燃性
の向上など従来の技術に見られない驚くべき改善
的が見出された。[Table] As seen in this example, a system in which 90% or more finely powdered melamine with a particle size of 10 microns or less is added to polyvinyl chloride resin is compared with a comparative example in which normal melamine with a particle size of 20 to 110 microns is added. Surprising improvements not seen in conventional technologies were discovered, including improved mechanical strength, whiteness, thermal stability, and flame retardancy.