JP2008266428A - Heat resistant film and method for producing the same - Google Patents

Abstract

The present invention provides a heat-resistant film having a good balance between cost and performance by using together with polyether ether ketone as a raw material, polyether sulfone, which is a relatively inexpensive amorphous resin, and a method for producing the same. For the purpose.
A resin composition 1 containing polyether ether ketone and polyether sulfone as a resin component, and the content of the polyether ether ketone in the resin component is 70% by weight or more is heated to form a film. Since it was rapidly cooled after being molded into a material, the tensile elastic modulus specified in JIS K7127 is 1500 MPa or more and the folding resistance specified in JIS P8115 is 2000 times or more despite being a combined system of PEEK and PES. Can be obtained.
[Selection] Figure 1

Description

  The present invention relates to a heat-resistant film excellent in flexural fatigue resistance comprising a resin composition obtained by mixing polyether ether ketone and polyether sulfone, and a method for producing the same.

  Polyetheretherketone resins are excellent in rigidity, flame retardancy, heat resistance, electrical insulation, chemical resistance, etc., and are therefore used in electronic parts such as flexible printed boards and IC carrier tapes.

  As another electronic component, for example, in a color image forming apparatus, after a toner image formed on a photosensitive member is once transferred, an intermediate transfer belt used for transferring the transferred image onto a transfer material, or a photosensitive member is used. A semiconductive belt such as a transfer conveyance belt used for directly transferring a toner image formed on a body onto a transfer material is used.

The semiconductive belt used in these image forming apparatuses is required to be excellent in mechanical strength such as initial elastic modulus in order to form a highly accurate image. As such a semiconductive belt, as described above, polyether ether ketone, which is a super engineering plastic excellent in various characteristics, is extruded into a cylindrical shape by an extrusion molding device, and then cut is proposed. (Patent Document 1).
Japanese Patent Laid-Open No. 6-254941

  However, although polyether ether ketone is excellent in properties such as rigidity, it has a rigid structure because it is a crystalline resin, so that the effect of improving bending fatigue resistance is not sufficient, and it is semiconductive. There is a problem that it is difficult to use as a flexible belt or a flexible printed circuit board.

  Therefore, in the present invention, by using together with polyether ether ketone as a raw material, polyether sulfone, which is a relatively inexpensive amorphous resin, a heat-resistant film having a good balance between cost and performance and its production It aims to provide a method.

  As a result of intensive studies by the present inventors in order to solve the above-mentioned problems, when polyether ether ketone (hereinafter referred to as PEEK) is heated and formed into a film and then rapidly cooled, the crystallinity of PEEK decreases. It has been found that the bending fatigue resistance is drastically improved. Furthermore, when a resin composition obtained by mixing PEEK with polyethersulfone (hereinafter referred to as PES) is rapidly cooled, if the PEEK content in the resin composition is 70% by weight or more, good bending fatigue resistance is maintained. The inventors have found that this is possible and have completed the present invention.

  That is, the heat resistant film according to the present invention comprises a resin composition containing polyether ether ketone and polyether sulfone as resin components, and the content of the polyether ether ketone in the resin component is 70% by weight. The tensile elastic modulus specified in JIS K7127 is 1500 MPa or more, and the folding resistance specified in JIS P8115 is 2000 or more.

  According to the above configuration, by using an alloy of expensive PEEK and relatively inexpensive PES in combination, the bending fatigue resistance (number of foldings) is significantly higher than that of a conventional film using PEEK alone. Thus, it is possible to provide a heat-resistant film having a good balance between cost and performance.

  The resin composition may contain a conductive filler, whereby a conductive heat resistant film can be obtained. Moreover, it is also possible to obtain a semiconductive belt using the said heat resistant film by adjusting the compounding quantity of a conductive filler.

  The heat resistant film according to the present invention comprises a resin composition containing polyether ether ketone and polyether sulfone as resin components, wherein the content of the polyether ether ketone in the resin component is 70% by weight or more. It can be obtained by heating to form a film and then rapidly cooling.

  As the quenching condition, when the resin component 100% by weight of polyetheretherketone is heated to form a film and then cooled, the crystallinity of the polyetheretherketone by the density method is 25% or less. It can be a condition.

  That is, when the resin composition of polyether ether ketone 100% by weight as a resin component is formed into a film and then slowly cooled, the crystallinity becomes about 40%. When the resin composition is formed into a film and then rapidly cooled, The degree of crystallinity is 25% or less. And bending fatigue resistance (folding frequency | count) can be improved significantly by making a crystallinity degree into 25% or less.

  Therefore, if the quenching conditions are set to the above conditions and up to 30% by weight of the resin composition is replaced from PEEK to PES, the raw material cost is maintained while maintaining a good tensile elastic modulus compared to the conventional PEEK 100% film. Can be reduced, and the bending fatigue resistance can be greatly improved.

  Moreover, the said resin composition may contain a conductive filler, and in this case, it becomes possible to obtain a heat resistant film having conductivity. Thereby, as described above, a semiconductive belt excellent in initial elastic modulus, flame retardancy, and bending fatigue resistance can be obtained.

  In order to rapidly cool the film-like resin composition, a gaseous or liquid refrigerant can be brought into contact with PEEK, or a cooling plate made of a material such as a metal having a large heat capacity can be brought into contact with PEEK. The methods can be carried out alone or in combination.

  The heat-resistant film according to the present invention can be rolled between rolls and formed into a film shape, and can be extruded by a T-die or the like. Moreover, when obtaining a semiconductive belt, a seamless belt can be obtained by cutting the cylindrical heat-resistant film extruded from the extrusion molding apparatus provided with the circular die.

  The PEEK used in the present invention is not particularly limited, but as long as the repeating unit has an ether bond and a carbonyl group as shown in Chemical Formula 1 (wherein n is a positive integer). .

  The conductive filler is not particularly limited as long as it is a filler that can be used to impart conductivity to the semiconductive belt, but carbon black, graphite, iron, copper, copper alloy, nickel, aluminum or other metals or alloys, Alternatively, fine powders of metal oxides such as tin oxide, zinc oxide, titanium oxide tin oxide-indium oxide or tin oxide-antimony oxide composite oxide are exemplified. These metals, alloys or metal oxides can be used alone or in admixture of two or more. Among them, it is preferable to use carbon black because it is inexpensive and versatile.

The semiconductive belt in the present invention has a volume resistivity (150 μm thickness) of 10 ⁶ Ω · cm to 10 ¹³ Ω used for an intermediate transfer belt or a transfer conveyance belt by blending the conductive filler. -Belts adjusted to the cm range. As long as the heat resistant film according to the present invention has a thickness of several tens of μm to several hundreds of μm, it can be used without any problem as an electronic component or a semiconductive belt.

  In the present invention, the resin composition containing polyether ether ketone and polyether sulfone as the resin component, and the content of the polyether ether ketone in the resin component is 70% by weight or more is heated to form a film. Because it is rapidly cooled after molding, it has the characteristics that the tensile elastic modulus specified in JIS K7127 is 1500 MPa or more and the folding resistance specified in JIS P8115 is 2000 times or more despite being a combined system of PEEK and PES. The provided heat resistant film can be obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing a production apparatus for producing a semiconductive belt as a heat resistant film according to the present invention. In this embodiment, the extrusion apparatus 3 which extrudes from the die head 2 the resin composition 1 which contains PEEK and PES as a resin component and melt-kneaded carbon black which is an electroconductive filler there further is provided. The die head 2 has a circular die and extrudes the resin composition 1 into a cylindrical shape.

  The blending ratio of PEEK in the resin component may be 70% by weight or more, but considering raw material costs, it is preferably 70% to 95% by weight, and at least 5% by weight is preferably blended with PES.

  The resin composition 1 extruded from the die head 2 is cooled by a sizing die 4, adjusted in shape, taken up by a take-up machine 5 arranged on the downstream side thereof, cut into a predetermined length, and cylindrical A seamless semiconductive belt can be obtained.

  In the present embodiment, a sizing die 4 can be used as a means for rapidly cooling the resin composition 1. That is, in order to melt the resin composition containing PEEK, it is necessary to heat the temperature in the die head 2 to about 370 ° C. Normally, the sizing die 4 is set to 150 ° C. to 300 ° C., In the present invention, the resin composition can be rapidly cooled by setting the temperature of the sizing die 4 to 0 ° C. to 80 ° C.

  As the rapid cooling means, in addition to the sizing die 4, for example, it is also possible to employ a cold air supply means for blowing cold air on the outer peripheral surface of the PEEK drawn out in a cylindrical shape. Further, the sizing die 4 and the cold air supply means are used. It can also be used together.

  As another method for obtaining a semiconductive belt, for example, as shown in FIG. 2, it is also possible to use a mold 6 composed of an upper mold 6a and a lower mold 6b. This method will be described in detail. First, PEEK, PES and carbon black are melt-kneaded to prepare a pellet-shaped resin composition 1. Recesses are formed in the mating surfaces of the upper mold 6a and the lower mold 6b of the mold 6 so that when the mold 6 is closed, a space with a certain gap is formed in the mold. It has become.

  Next, when the pellet-shaped resin composition 1 is set in the mold 6 and the upper mold 6 a and the lower mold 6 b are heated and closed so as to be closed, the resin composition 1 is contained in the mold 6. Is formed into a sheet. And a heat resistant film can be obtained by rapidly cooling the resin composition 1 with a metal mold | die with the metal mold | die 6 closed. And a semiconductive belt can be obtained by shape | molding the obtained sheet-like heat resistant film in a cylinder shape.

[Preparation of heat-resistant film]
(1) Setting of rapid cooling conditions Using the mold 6 described in FIG. 2 of the first embodiment, first, PEEK (450G manufactured by Victrex) 100% is used as the resin composition, and this pellet raw material is used. After being set in the above-described mold 6 and press-molded at 20 MPa while being heated to 370 ° C., the mold 6 was put into water and quenched to obtain a film having a thickness of 150 μm.

  And the PEEK crystallinity degree of the said film when water temperature was changed was measured. In addition, as another cooling method, the method of carrying out a cooling press (20 MPa) with the press machine set to the hot platen temperature 50 degreeC immediately after the hot press shaping | molding in said 370 degreeC was implemented. The crystallinity was measured based on the following formula (1).

That is, the crystallinity of PEEK in the present invention was calculated by the density method calculated from the sample density. Specifically, a liquid with a higher specific gravity than the sample (carbon tetrachloride: 1.60 g / cm ³ at30 ° C) and a liquid with a lower specific gravity than the sample (benzene: 0.88 g / cm ³ at30 ° C) in a constant temperature bath at 30 ° C And a liquid is added until the sample stops suspended, and the density of the mixed liquid is defined as the density d of the sample. Then, the following formula is established.

1 / d = (Xc / dc) + {(1-Xc) / da}
Where Xc: (weight fraction) crystallinity
d: Sample density
dc: density of crystal region (1.382 g / cm ³ )
da: density of amorphous region (1.265 g / cm ³ )
∴Xc = dc (d−da) / d (dc−da) × 100 Equation (1)

  In addition, as other evaluation tests, a tensile elastic modulus and a bending fatigue resistance test described later were performed. The results are shown in Table 1. From Table 1, in the method of cooling the mold in water, it has been found that the crystallinity is 25% or less in any water temperature range of 3 ° C to 70 ° C. On the other hand, in the cooling by the cooling press, the heat resistant film was gradually cooled, and as a result, the crystallinity was as high as 40%. It was confirmed that the bending fatigue resistance (number of foldings) was significantly improved in the former when the crystallinity of PEEK was 25% or less and when the crystallinity was 40%. .

(2) Production of heat-resistant film A heat-resistant film was produced using the mold 6 and evaluated for tensile elastic modulus and bending fatigue resistance. The test conditions are described below.

  PEEK (450P made by Victrex) and PES (Sumika Excel 4100P made by Sumitomo Chemical Co., Ltd.) were used as resin components, and these were mixed at various ratios. Further, in this example, 12 parts by weight of carbon black (acetylene black: “Denka Black Granules” manufactured by Denki Kagaku Kogyo Co., Ltd.) is added to 100 parts by weight of the resin component, and melted and kneaded with a plast mill to form a compound resin composition. 1 was produced.

  The compound-like resin composition 1 was formed into a film by press molding at 370 ° C. and 20 MPa, and then poured into the water together with the mold 6 to rapidly cool to produce a heat-resistant film (semiconductive film) having a thickness of 150 μm. did. In addition, as a rapid cooling condition of a heat resistant film, it decided to cool by putting a metal mold | die in 3 degreeC water from the said item (1). The following evaluation tests were performed on the four types of samples obtained as described above.

[Evaluation test]
(1) Tensile modulus The tensile modulus was measured according to JIS K7127. That is, measurement was performed at a test speed of 50 mm / min using a 10 mm × 150 mm strip test piece.

(2) Bending fatigue resistance Bending fatigue resistance was evaluated by measuring the number of foldings in accordance with JIS P8115.

[Evaluation results]
The evaluation test results are shown in Table 2. From Table 2, the sample 1 in which the PEEK content in the resin component is 70% by weight or more under the present rapid cooling conditions has a tensile elastic modulus of 2000 MPa or more and an excellent bending resistance of 6000 or more. It can be seen that it exhibits fatigue properties. On the other hand, with respect to Sample 2 and Sample 3 in which the content of PEEK in the resin component is less than 70% by weight, the folding endurance number is drastically decreased. That is, it was confirmed that the bending fatigue resistance does not gradually decrease according to the PEEK content but changes rapidly.

  Also, for sample 4 (crystallinity 40%) cooled under cooling conditions such that the crystallinity of the film using PEEK 100% as the resin component is 25% or more, the composition of the resin component is the same as that of sample 1 Nevertheless, the number of folding endurance (flexural fatigue resistance) showed the lowest value in all samples. Thus, it can be seen that the cooling condition of the heat resistant film has a great influence on the bending fatigue resistance.

Schematic which shows the manufacturing apparatus which manufactures the semiconductive belt which is the heat resistant film which concerns on this invention Schematic sectional view showing a manufacturing apparatus different from FIG. FIG. 2 is a schematic sectional view showing a state in which the mold in FIG. 2 is closed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Resin composition 2 Die head 3 Extruder 4 Sizing die 5 Take-up machine

Claims (6)

It consists of a resin composition containing polyether ether ketone and polyether sulfone as a resin component, and the content of the polyether ether ketone in the resin component is 70% by weight or more, and is a tensile specified in JIS K7127 A heat-resistant film characterized by having an elastic modulus of 1500 MPa or more and a folding endurance specified in JIS P8115 of 2000 or more. The heat-resistant film according to claim 1, wherein the resin composition contains a conductive filler. A semiconductive belt using the heat resistant film according to claim 2. A resin composition containing polyether ether ketone and polyether sulfone as a resin component, and the content of the polyether ether ketone in the resin component is 70% by weight or more was heated to form a film. A method for producing a heat-resistant film, which is rapidly cooled later. The quenching condition is a condition that when the resin component 100% by weight of polyetheretherketone is heated to form a film and then cooled, the crystallinity of the polyetheretherketone by the density method is 25% or less. The method for producing a heat resistant film according to claim 4, wherein: The method for producing a heat resistant film according to claim 4, wherein the resin composition contains a conductive filler.

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