JPH0518864B2 - - Google Patents
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- Publication number
- JPH0518864B2 JPH0518864B2 JP58210497A JP21049783A JPH0518864B2 JP H0518864 B2 JPH0518864 B2 JP H0518864B2 JP 58210497 A JP58210497 A JP 58210497A JP 21049783 A JP21049783 A JP 21049783A JP H0518864 B2 JPH0518864 B2 JP H0518864B2
- Authority
- JP
- Japan
- Prior art keywords
- acetal resin
- weight
- added
- acid
- parts
- 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.)
- Expired - Lifetime
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- Compositions Of Macromolecular Compounds (AREA)
Description
本発明は、アセタール樹脂の本来有する機械的
性質、熱安定性及び成形品外観を実質的に全く損
なわずして射出成形の際の離型性を極めて高度に
改善したアセタール樹脂組成物に関するものであ
る。
アセタール樹脂は、バランスのとれた機械的性
質、優れた耐摩擦摩耗性、優れた耐熱性等の特性
の故に、自動車、電気機器、建材等の諸工業の分
野で広範囲の用途にわたつて使用されている。
また殆んどの場合、その成形は射出成形に依つ
ており、機械部品及び精密機構部品としての用途
が多いアセタール樹脂の場合、それら成形品の構
造は複雑な場合が極めて多い。複雑な構造の一例
として例えば、単一成形品に於て厚肉部と薄肉
部、更には超薄肉部が互いに入り組んだ上、更に
中空円筒状突起物等が備わつている等の形状等が
あるが、それらはまた、数ｇから高々数10ｇ程度
の重量の小物部品の場合が多い。このような複雑
な形状の成形品の場合、溶融樹脂がシリンダーか
ら射出され金型内で冷却されたのちの、成形品の
突出し離型は出来るだけスムーズでなけらればな
らない。何故なら、成形された複雑形状の製品を
過度に強い力で突出し離型した場合、製品は破損
された状態で得られたり、また破損を生じない迄
も、過度の力で離型された場合、製品に於て過度
の力を受けた箇所は成形ひずみを製品内部に保存
することとなり、製品が長期にわたつて使用され
る場合、それらの影響が、やがて悪く露呈し、何
れの場合も極めて好ましくない。
アセタール樹脂は、エンジニアリング・プラス
チツクとして求められる性質の殆んどを備えた極
めて有用な成形材料であるが故に、前述の如き用
途に於て使用されているものであるが、それらの
性質に加えて更に極めて優れた流動性をも有して
いるため、必然的に複雑な形状の製品に用いられ
る場合が多くなり、前述の理由に依り出来うる限
り小さな離型力で製品が得られる事が切に望まれ
るのである。その目的を達せんが為、本発明者ら
は、鋭意検討した結果、アセタール樹脂に、炭素
数22〜32の高級脂肪酸（以下、化合物(A)と略す）
の１種以上を添加する事により、アセタール樹脂
本来の機械的性質、熱安定性及び成形品外観を実
質的に全く損なわずして、離型力の極めて小さい
アセタール樹脂組成物の得られる事を見い出し
た。
炭素数21以下の脂肪酸を用いた場合、離型性改
善効果は若干認められるが熱安定性を著しく損
ね、著しく外観不良の成形品を得る事のなり、好
ましくない。
また、本発明に於ける効果は、先に出願した特
願昭57−114730によつて提示されているアセター
ル樹脂に、リノール酸を二量化する事によつて得
られるジカルボン酸（以下「ダイマー酸」と略記
する）の金属塩を添加してなる効果を更に凌駕す
るものである。
本発明に於て使用する炭素数22〜32の高級脂肪
酸とはベヘン酸、セロチン酸、モンタン酸及びラ
クセル酸等を意味するが、なかでも、ベヘン酸及
びモンタン酸等は、特に効果的で好ましい。
化合物(A)の添加量は、アセタール樹脂100重量
部に対し0.001〜１重量部、好ましくは0.005〜0.5
重量部が適当である。この場合、0.001重量部未
満の量では効果は実用上不十分であり、１重量部
を超える量ではアセタール樹脂本来の性質のうち
特に成形品外観（色調）の悪化をもたらす。
本発明の組成物で用いられるアセタール樹脂と
は、ホルムアルデヒド単量体またはその３量体
（トリオキサン）もしくは４量体（テトラオキサ
ン）などの環状オリゴマーを原料として製造され
た実質的にオキシメチレン単位のみからなるオキ
シメチレンホモポリマーおよび上記原料とエチレ
ンオキサイド、プロピレンオキサイド、エピクロ
ルヒドリン、１，３−ジオキソラン、１，３−ジ
オキセパン、グリコールのホルマール、ジグリコ
ールのホルマール等の環状エーテルとから製造さ
れた、オキシメチレン単位とC2以上のオキシア
ルキレン単位とからなるオキシメチレンコポリマ
ーを包含する。
また本発明の組成物には、公知の熱安定剤、酸
化防止剤たとえば好適な組み合わせ系として、立
体障害性フエノール類とアミジン化合物および／
またはポリアミドおよび／またはポリビニルピロ
リドンなどの添加が可能であり、その他、本発明
の効果を損なわない限りにおいて、有機、無機の
充填剤、従来公知の添加剤なども添加しうる。
本発明のアセタール樹脂組成物を製造する方法
は各種採用できるが、各成分を混合もしくは溶融
混練することは必須である。
溶融混練のために使用される装置としては、各
種押出機、ニーダー、バンバリー・ミキサー、ミ
キシングロール等の一般的な混練機が用いられ、
その際の混練方法としては、Ｖ字型ブレンダーの
如き緩やかな混合装置又はヘンシエル・ミキサー
の如き高速流動混合装置によりドライブレンドし
た混合物または、溶媒に溶解した溶液、乳化液、
懸濁液等の状態で撹拌混合した後に、乾燥した混
合物を上記の各種の混練機に投入する方法、上記
の各種の混練機等により均質な溶融状態のアセタ
ール樹脂組成物に本発明の化合物(A)を添加する方
法等、各種の方法が可能である。
溶融混練の温度は、用いるアセタール樹脂、混
合混練装置の機能等の各種条件および目的によつ
て適当に選定されるが、アセタール樹脂の融点以
上分解温度以下および各種添加剤の分解温度以下
の温度範囲であり、一般に175〜230℃の温度範囲
が好ましい。
以下実施例および比較例をあげて本発明をさら
に具体的に説明する。
なお、以下の記載に於て、極限粘度〔η〕は２
重量％のα−ピネンを添加したｐ−クロロフエノ
ール中で、60℃で測定した値を示す。また、安定
剤等の添加量である〔phr〕はアセタール樹脂
100重量部当りの重量部を意味する。
実施例１〜７および比較例１〜６
〔η〕＝1.1（dl／ｇ）の、エチレンオキシドか
ら誘導されるコモノマー単位を約2.5重量％の量
で含有する、トリオキサン−エチレンオキシド・
コポリマーに、熱酸化安定剤としてメラミン
0.2phr、トリエチレングリコール−ビス−３−
（３−(t)−ブチル−４−ヒドロキシ−５−メチル
フエニル）プロピオネート0.5phr、水酸化マグネ
シウム（Mg（OH）2）0.1phrをそれぞれ添加し、
表１記載の如く化合物(A)を、それぞれの添加量に
て添加してなる系を、Ｌ／Ｄ＝30、直径50mmのベ
ント付二軸押出機を用いて、熱安定化処理し、安
定なオキシメチレン共重合体組成物を得た。
比較例１〜６として、表２に記載の如く、実施
例１〜７に於て化合物(A)を添加する替わりに、化
合物(B)を添加する事以外は全く同じプロセスを経
た押出しペレツトを得た。
実施例１〜７および比較例１〜６によつて得た
各試料について、後記、注(1)〜注(5)記載の各試験
条件下により離型力の測定および成形品外観（色
調）、熱安定性試験、衝撃強度の試験をそれぞれ
実施し、その結果を表１および表２に示した。
実施例８および比較例７
アセタール樹脂が〔η〕＝1.3（dl／ｇ）で、無
水酢酸により末端OH基がアセチル化されたオキ
シメチレン・ホモポリマーである事以外は、実施
例１と同様の操作を行ない、押出しペレツトを得
た。
比較例７として、ベヘン酸1000ppmを含まない
事以外は、実施例８と同様の操作を行ない、押出
しペレツトを得た。両試料について実施例１に於
けると同様の各種の試験を実施した。試験結果を
表(1)及び表(2)に示す。
The present invention relates to an acetal resin composition that has extremely improved mold releasability during injection molding without substantially impairing the inherent mechanical properties, thermal stability, or appearance of molded products. be. Acetal resin has properties such as well-balanced mechanical properties, excellent friction and wear resistance, and excellent heat resistance, so it is used for a wide range of applications in various industrial fields such as automobiles, electrical equipment, and building materials. ing. Furthermore, in most cases, the molding relies on injection molding, and in the case of acetal resin, which is often used as mechanical parts and precision mechanism parts, the structures of these molded products are often extremely complex. An example of a complex structure is, for example, in a single molded product, a thick part, a thin part, and even an ultra-thin part are intertwined with each other, and the shape is also provided with a hollow cylindrical protrusion. However, they are also often small parts weighing from several grams to several tens of grams at most. In the case of molded products with such complex shapes, the ejection and release of the molded product after the molten resin is injected from the cylinder and cooled in the mold must be as smooth as possible. This is because if a molded product with a complex shape is ejected and released from the mold with excessive force, the product may be damaged. , parts of the product that are subjected to excessive force will store molding strains inside the product, and if the product is used for a long period of time, these effects will eventually be exposed and become extremely Undesirable. Acetal resin is an extremely useful molding material that has most of the properties required as an engineering plastic, and is therefore used in the applications mentioned above. Furthermore, because it has extremely excellent fluidity, it is inevitably used in products with complex shapes, and for the reasons mentioned above, it is essential that products can be obtained with as little mold release force as possible. It is desired by In order to achieve this objective, the present inventors have conducted intensive studies and found that higher fatty acids having 22 to 32 carbon atoms (hereinafter abbreviated as compound (A)) are added to acetal resin.
By adding one or more of the following, it is possible to obtain an acetal resin composition with extremely low mold release force without substantially impairing the mechanical properties, thermal stability, or appearance of the molded product inherent to the acetal resin. I found it. When a fatty acid having 21 carbon atoms or less is used, a slight improvement in mold releasability is observed, but the thermal stability is significantly impaired and a molded product with a significantly poor appearance is obtained, which is not preferable. Furthermore, the effect of the present invention is obtained by adding dicarboxylic acid (hereinafter referred to as "dimer acid") obtained by dimerizing linoleic acid to acetal resin as proposed in the previously filed Japanese Patent Application No. 57-114730. This effect further exceeds the effect obtained by adding metal salts (abbreviated as ``)''. The higher fatty acids having 22 to 32 carbon atoms used in the present invention include behenic acid, cerotic acid, montanic acid, and lacceric acid, among which behenic acid and montanic acid are particularly effective and preferred. . The amount of compound (A) added is 0.001 to 1 part by weight, preferably 0.005 to 0.5 part by weight, per 100 parts by weight of the acetal resin.
Parts by weight are appropriate. In this case, if the amount is less than 0.001 part by weight, the effect will be insufficient in practical terms, and if the amount exceeds 1 part by weight, the appearance (color tone) of the molded product will deteriorate, especially among the properties inherent to the acetal resin. The acetal resin used in the composition of the present invention is made from substantially only oxymethylene units produced from formaldehyde monomers or cyclic oligomers such as their trimers (trioxanes) or tetraoxanes (tetraoxanes). An oxymethylene homopolymer and an oxymethylene unit produced from the above raw materials and a cyclic ether such as ethylene oxide, propylene oxide, epichlorohydrin, 1,3-dioxolane, 1,3-dioxepane, glycol formal, diglycol formal, etc. and an oxyalkylene unit of C 2 or more. The compositions of the present invention may also contain known heat stabilizers, antioxidants, such as sterically hindered phenols and amidine compounds and/or as suitable combination systems.
Alternatively, polyamide and/or polyvinylpyrrolidone can be added, and organic and inorganic fillers and conventionally known additives can also be added as long as they do not impair the effects of the present invention. Although various methods can be adopted for producing the acetal resin composition of the present invention, it is essential to mix or melt-knead each component. As equipment used for melt-kneading, general kneading machines such as various extruders, kneaders, Banbury mixers, and mixing rolls are used.
The kneading method at this time includes a mixture dry-blended using a gentle mixing device such as a V-shaped blender or a high-speed fluid mixing device such as a Henschel mixer, a solution dissolved in a solvent, an emulsion,
The compound of the present invention ( Various methods are possible, such as adding A). The melt-kneading temperature is appropriately selected depending on various conditions and purposes such as the acetal resin used and the function of the mixing and kneading equipment, but it is within the temperature range of above the melting point of the acetal resin and below the decomposition temperature and below the decomposition temperature of various additives. and generally a temperature range of 175 to 230°C is preferred. EXAMPLES The present invention will be explained in more detail below with reference to Examples and Comparative Examples. In addition, in the following description, the intrinsic viscosity [η] is 2
The values are shown measured at 60°C in p-chlorophenol to which % by weight of α-pinene was added. In addition, [phr], which is the amount of stabilizers added, is the acetal resin.
Means parts by weight per 100 parts by weight. Examples 1-7 and Comparative Examples 1-6 Trioxane-ethylene oxide containing comonomer units derived from ethylene oxide in an amount of about 2.5% by weight, [η] = 1.1 (dl/g)
Melamine as a thermal oxidative stabilizer in copolymers
0.2 phr, triethylene glycol-bis-3-
Add 0.5 phr of (3-(t)-butyl-4-hydroxy-5-methylphenyl) propionate and 0.1 phr of magnesium hydroxide (Mg(OH) 2 ), respectively.
A system in which compound (A) was added in the respective amounts as shown in Table 1 was thermally stabilized using a vented twin screw extruder with L/D = 30 and a diameter of 50 mm. An oxymethylene copolymer composition was obtained. As Comparative Examples 1 to 6, as shown in Table 2, extruded pellets were prepared using exactly the same process as in Examples 1 to 7 except that compound (B) was added instead of compound (A). Obtained. For each sample obtained in Examples 1 to 7 and Comparative Examples 1 to 6, the mold release force was measured and molded product appearance (color tone) under each test condition described in Notes (1) to (5) below. , a thermal stability test, and an impact strength test were conducted, and the results are shown in Tables 1 and 2. Example 8 and Comparative Example 7 Same as Example 1 except that the acetal resin was [η] = 1.3 (dl/g) and was an oxymethylene homopolymer whose terminal OH group was acetylated with acetic anhydride. The operation was carried out to obtain extruded pellets. As Comparative Example 7, extruded pellets were obtained by carrying out the same operation as in Example 8 except that 1000 ppm of behenic acid was not included. Various tests similar to those in Example 1 were conducted on both samples. The test results are shown in Table (1) and Table (2).
【表】【table】
【表】【table】
Claims (1)
酸の１種以上を添加してなるアセタール樹脂組成
物。 ２ 炭素数22〜32の高級脂肪酸をアセタール樹脂
100重量部に対し、0.001〜１重量部添加してなる
特許請求の範囲第１項記載のアセタール樹脂組成
物。[Scope of Claims] 1. An acetal resin composition obtained by adding one or more types of higher fatty acids having 22 to 32 carbon atoms to an acetal resin. 2 Acetal resin of higher fatty acids with 22 to 32 carbon atoms
The acetal resin composition according to claim 1, which is added in an amount of 0.001 to 1 part by weight per 100 parts by weight.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21049783A JPS60104151A (en) | 1983-11-09 | 1983-11-09 | Acetal resin composition |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21049783A JPS60104151A (en) | 1983-11-09 | 1983-11-09 | Acetal resin composition |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60104151A JPS60104151A (en) | 1985-06-08 |
| JPH0518864B2 true JPH0518864B2 (en) | 1993-03-15 |
Family
ID=16590331
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP21049783A Granted JPS60104151A (en) | 1983-11-09 | 1983-11-09 | Acetal resin composition |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60104151A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6156834A (en) * | 1998-03-20 | 2000-12-05 | Asahi Kasei Kogyo Kabushiki Kaisha | Polyacetal resin composition |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5413551A (en) * | 1977-07-04 | 1979-02-01 | Asahi Chem Ind Co Ltd | Polyoxymethylene composition |
| US4409351A (en) * | 1981-06-15 | 1983-10-11 | General Electric Company | Compositions comprising thermoplastic resin and long chained fatty acid |
-
1983
- 1983-11-09 JP JP21049783A patent/JPS60104151A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60104151A (en) | 1985-06-08 |
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