JPH05311074A - Aromatic polysulfone molding composition - Google Patents

Abstract

PURPOSE:To obtain an aromatic polysulfone molding composition of improved moldability. CONSTITUTION:100 pts.wt. aromatic polysulfone is mixed with 0.3-5 pts.wt. ethylene/tetrafluoroethylene copolymer and 0-25 pts.wt. carbon fiber or powder to obtain the composition markedly improved in moldability, especially molding flow, inhibition of mold deposit and mold release.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding composition which can improve the moldability of an aromatic polysulfone by containing a small amount of a specific fluorocarbon polymer in the aromatic polysulfone. More specifically, according to the present invention, it is possible to improve fluidity, mold deposit and mold releasability during injection molding.

[0002]

2. Description of the Related Art Since aromatic polysulfones are non-crystalline, they are isotropic and have a low molding shrinkage, and since they have a high glass transition point, they are excellent in strength, elastic modulus and creep resistance at high temperatures. Utilizing these properties, they are widely used as electronic members such as IC trays, OA, and AV equipment parts that require high dimensional accuracy and high heat resistance. However, in the case of injection molding of precision parts, the fluidity of the aromatic polysulfone itself, the releasability when the molded products are taken out of the mold, the mold stains when molding many (so-called mold deposit), etc. Moldability often becomes a problem,
It has a great impact on the yield and productivity of molded products.

On the other hand, it is known that when a fluoropolymer is mixed with an aromatic polysulfone, a self-lubricating property can be imparted, and mold releasability from a mold and sliding property are improved. For example, in JP-A-58-160353, a composition comprising an aromatic polysulfone, a fluoropolymer and oxybenzoyl polyester is a sliding material having excellent wear characteristics when a soft metal is used as a counter material. Is listed. Further, by blending a fluorine-based polymer in an aromatic polysulfone composition having glass fiber, a fibrous reinforcing material such as wollastonite or the like, talc, and an inorganic filler such as glass beads to reduce molding shrinkage, An example in which the releasability from the mold is improved is described in JP-A-60-23448. Further, it is described in JP-A-60-38465 that a composition comprising an aromatic polysulfone, a fluoropolymer and a carbon fiber has excellent sliding properties. In JP-A-3-252457, a molecule is disclosed. It has been shown that the sliding property and the releasability are improved by blending a specific fluoropolymer having a stabilized terminal.

[0004]

In all of the examples described in these prior documents, polytetrafluoroethylene (PTF) was used as the fluoropolymer in the composition.
E) is used. Certainly, the effect of PTFE is effective in improving the sliding characteristics, and at the same time, the releasability is also improved.
In the case of E, a large amount is required to obtain the desired effect, which is not always satisfactory because it adversely affects other physical properties such as strength.

On the other hand, the present inventors have found that ethylene-tetrafluoroethylene copolymer (ETFE) has a better releasing effect than PTFE which is usually used, and this is because PT
They have found that it is more advantageous than compounding FE, and completed the present invention.

[0006]

That is, the present invention provides an aromatic polysulfone molding composition in which 0.3 to 5 parts by weight of ETFE and 0 to 25 parts by weight of carbon fiber are blended with 100 parts by weight of aromatic polysulfone. Regarding

The above-mentioned Japanese Patent Laid-Open No. 60-23448 discloses that
As the fluorine-based polymer other than PTFE, for example, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), ethylene-hexafluoropropylene copolymer (FEP), ethylene-tetrafluoroethylene copolymer (ETFE), poly Chlorotrifluoroethylene (PCTFE), vinylidene fluoride resin (PV
dF) is generally mentioned in the description, but its specific effect has not been clarified. Especially for those skilled in the art
TFE, PCTFE and PVdF are not usually regarded as resins having excellent self-lubricating properties.

However, the present inventors have found that the addition of ETFE improves the releasability with a smaller amount than that of PTFE, and also improves the fluidity and mold deposit.

The aromatic polysulfone used in the present invention is a linear polymer in which allylene units are connected by ether and sulfone bonds, and is UDEL (manufactured by Amoco), VICT.
It is a resin marketed under the trademark such as REX (manufactured by ICI). Further, ETFE is a copolymer having tetrafluoroethylene-ethylene as a basic unit and usually containing 2 to 15% by weight of a fluorine-containing olefin.
Commercially available products such as TFE (manufactured by Daikin Industries, Ltd.), Aflon COP (manufactured by Asahi Glass Co., Ltd.), and Tefzel (manufactured by DuPont) can be used. These ETFE
Has a melt flowability of usually 1 to 20 in terms of the amount of resin extruded per 10 minutes (referred to as MI) measured at 297 ° C. and a load of 5 kg.

The amount of ETFE blended in the present invention is
The amount is 0.3 to 5 parts by weight, preferably 0.5 to 3 parts by weight, based on 100 parts by weight of the aromatic polysulfone. If the amount of ETFE is less than 0.3 parts by weight, the effect of mold release is difficult to recognize,
If the amount exceeds 5 parts by weight, a separation layer of ETFE is formed on the surface of the molded product, resulting in a poor appearance.

In the present invention, the method of blending ETFE is not particularly limited, but it is preferable to melt-mix ETFE up to about 10% by weight with aromatic polysulfone and then melt-dilute this with aromatic polysulfone to a desired ratio.

The releasing effect of ETFE in the present invention is more effective when a carbon fiber or powder is blended for the purpose of strengthening strength, imparting conductivity, and imparting slidability. As the carbon-based fiber or powder, those conventionally known may be used without particular limitation,
For example, high modulus and low modulus carbon fibers such as PAN type, pitch type, rayon type, lignin type, Ketjen black, acetylene black, furnace black, lamp black, thermal black, channel black, roll black, disk black, etc. Carbon black powder, and as graphite, natural graphite and artificial graphite (coal coke-based, petroleum coke-based, pitch-based) such as earth-like, scale-like, scale-like, and lump-like, and spherical or whisker-like carbon powder can be mentioned.

The amount of carbon fiber or powder is preferably 25 parts by weight or less with respect to 100 parts by weight of aromatic polysulfone. If it exceeds 25 parts by weight, the moldability will decrease.

If necessary, fibrous reinforcing materials such as glass fibers, ceramic fibers, potassium titanate fibers and aramid fibers, inorganic fillers such as calcium carbonate, talc, mica, clay and glass beads, liquid crystal polymers, A heat resistant resin such as polyimide or a colorant may be added.

[0015]

EXAMPLES Next, the molding composition of the present invention will be explained based on examples, but the present invention is not limited to these examples.

Examples 1 to 4 Aromatic polysulfone (UDEL P-170 manufactured by Amoco)
0) 7200 g and ETFE resin (Neotron ETFE EP-521 manufactured by Daikin Industries Ltd.) 800 g were kneaded at a cylinder temperature of 310 ° C. using a twin-screw kneading extruder (Labo Plastomill manufactured by Toyo Seiki Seisakusho KK). , An aromatic polysulfone composition having an ETFE content of 10% by weight was obtained. Using this masterbatch, the mixture was diluted with the same aromatic polysulfone in the same twin-screw kneading extruder to have the composition shown in Table 1, and for Examples 1, 3 and 4, pitch-based carbon fibers (Kureha Chemical Industry (Kureha Chemical Industry M-104T) manufactured by K.K. was mixed and pelletized.

Cylinder temperatures of 330 to 34 were obtained from these pellets using an injection molding machine (N-65 manufactured by Nippon Steel Co., Ltd.).
An IC tray was molded at 0 ° C. and a mold temperature of 130 ° C., and the releasing effect of each composition was examined. The mold release effect is the number of injection molding shots (limit number) until the mold release effect disappears due to mold deposit, etc.
Evaluated by Further, the appearance of the molded product was visually observed. The results are shown in Table 1.

Comparative Examples 1 to 6 Aromatic polysulfone molding compositions having the formulations shown in Table 1 were prepared. Comparative Examples 2 and 3 have the same ETFE as Example 1.
Are melt-blended and Comparative Examples 5 and 6 are ET of Example 1.
Compounding was carried out in the same manner except that FE was replaced with low molecular weight PTFE (Lubron L-5F manufactured by Daikin Industries, Ltd.).

Using the obtained pellets, an IC tray was injection-molded in the same manner as in Example 1 and the releasing effect and appearance were examined. The results are shown in Table 1.

[0020]

[Table 1]

[0021]

According to the present invention, the moldability of the aromatic polysulfone, especially the fluidity at the time of molding, the mold deposit, and the releasability can be improved.

Claims (1)

[Claims] 1. To 100 parts by weight of aromatic polysulfone,
An aromatic polysulfone molding composition comprising 0.3 to 5 parts by weight of an ethylene-tetrafluoroethylene copolymer and 0 to 25 parts by weight of carbon fiber or powder.