JP2001270995A - Heat resistant film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film which shows an excellent surface smoothness and transparency as well as heat resistance such as a shape retention at an elevated temperature, a low heat distortion, etc. SOLUTION: A resin composition composed of a thermoplastic resin having a glass transition temperature of >=100 deg.C and a specified layered-compound, is formed into a film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optically transparent film having excellent heat resistance.

[0002]

2. Description of the Related Art With the rapid progress of electronics technology, the field of liquid crystal display is expanding. In this field, devices are generally provided for various uses by forming them on a glass substrate having a transparent conductive layer. However, glass substrates have problems in mechanical strength, particularly brittleness, and reduce the durability of devices. Therefore, substrates treated with special treatment such as tempered glass have been used. However, at present, sufficient impact resistance has not been obtained. Also,
The glass substrate has a large specific gravity, and when incorporated into a portable device, the weight of the device increases. A glass substitute plastic film which is transparent and has excellent heat resistance, which solves such problems of glass, is desired.

[0003]

SUMMARY OF THE INVENTION The present invention provides a film having excellent surface smoothness and transparency, as well as excellent heat resistance such as shape retention at high temperatures and low dimensional changes upon heating. .

[0004]

That is, a first invention of the present invention is a heat-resistant film comprising a resin composition comprising a thermoplastic resin having a glass transition point of 100 ° C. or higher and a layered compound, The invention of No. 2 is a heat-resistant film in which a resin composition composed of a thermoplastic resin having a glass transition point of 100 ° C. or more and a layered compound is laminated on at least one surface of a film made of polyether sulfone.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The thermoplastic resin having a glass transition point of 100 ° C. or higher used in the present invention refers to a differential scanning calorimeter (measurement with a heat flux type DSC, JIS K 7121).
Glass transition point (intermediate point glass transition point) is 100 ° C
Above, for example, polyethylene naphthalate,
Examples include polysulfone, polyethersulfone, polyetheretherketone, and cycloolefin copolymer (amorphous polyolefin). A glass transition point is preferably high from the viewpoint of heat resistance, and more preferably 180 ° C.
Or more, more preferably at least 200 ° C., and most preferably polyethersulfone. When the glass transition point is lower than 100 ° C., heat resistance such as shape retention at a high temperature and low dimensional change upon heating is insufficient.

[0006] The layered compound used in the present invention is:
It is an inorganic substance having a layered crystal structure, such as, for example, montmorillonite, saponite, beidellite, nontronite, smectite-based clay minerals such as hectorite, vermiculite, halosite,
Other examples include natural or artificial clay minerals, mica, hydrotalcite, graphite, and the like. These layered compounds may be used alone or in combination of two or more. Of these, clay minerals are preferred.

[0007] Above all, a layered clay mineral which has been organized by an organic onium ion is preferable in terms of swelling with respect to a resin. Here, examples of the organic onium ion include hexyl ammonium ion, octyl ammonium ion, 2-ethylhexyl ammonium ion, dodecyl ammonium ion, octadecyl ammonium ion, dioctyl dimethyl ammonium ion, trioctyl ammonium ion, distearyl ammonium ion, and the like. Can be mentioned.

In the present invention, the glass transition point is 100 ° C.
The content of the layered compound in the composition comprising the thermoplastic resin and the layered compound is 0.1 from the viewpoints of surface smoothness, transparency, shape retention at high temperature, and low dimensional change during heating.
-10% by weight, more preferably 0.3-8% by weight, most preferably 0.5-5% by weight.

Further, the composition constituting the film of the present invention contains an antioxidant, as long as the effects of the present invention are not impaired.
It may contain an ultraviolet absorber, a light stabilizer, a lubricant, an anti-blocking agent, an antistatic agent, a surfactant, a dye, a pigment, a flame retardant, a plasticizer, and the like. The thickness of the film of the present invention is usually in the range of 0.1 to 0.6 mm, preferably 0.15 to 0.5 mm.

The preferred method for obtaining the heat-resistant film of the present invention includes: 1) a method of dispersing a layered compound in a solution containing a monomer constituting a thermoplastic resin, followed by polymerization, and 2) a method of producing a thermoplastic resin. Can be dispersed and mixed with a layered compound in a good solvent, and then the solvent can be removed, and 3) a method in which the layered compound is melt-kneaded with a thermoplastic resin.
By these methods, a composition suitable for the film of the present invention can be prepared.

The obtained composition is formed into a film or laminated by a known molding method such as a T-die method, a calender method, and a solvent casting method. The solvent used in the production by the solvent casting method is not particularly limited as long as it can dissolve a thermoplastic resin and a layered compound and can be cast. For example, N-1 methyl 2-pyrrolidone, N, N-dimethyl Formamide and the like are preferably used.

[0012]

Next, the present invention will be described more specifically with reference to examples. The components used in the examples and comparative examples are shown below. The glass transition point was measured with a DSC 220C (manufactured by Seiko Denshi Kogyo KK) at a heating rate of 10 ° C./min.

(Thermoplastic resin) PES (polyether sulfone) 4100G [Glass transition point: 225 ° C., Sumitomo Chemical Co., Ltd.]
(Layered compound) ・ SPN (organized hectorite) Lucentite SPN [Corp Chemical Co., Ltd.]

Example 1 Polyether sulfone and a layered compound were sufficiently mixed, and a resin temperature of 3 was obtained using a twin-screw kneader.
The mixture was melt-kneaded at 30 ° C. and melt-extruded from a die.
A film having a thickness of 2 mm was prepared and used.

Example 2 Polyether sulfone and a layered compound were sufficiently mixed, and a resin temperature of 3 was obtained using a twin-screw kneader.
Melt-kneaded at 30 ° C, melt-extruded from polyethersulfone and two-layer coextrusion die, total thickness 0.2mm
2 layer film (polyether sulfone + layered compound /
(Polyethersulfone = 0.1 / 0.1 mm) was prepared and used.

Example 3 95% by weight of polyether sulfone and 5% by weight of a layered compound were dissolved and dispersed in N-1 methyl 2-pyrrolidone to obtain a mixed solution. This mixed solution was coated on a polyether sunphone film having a thickness of 0.2 mm, and a film having a thickness of 0.205 mm was prepared by drying and used.

Comparative Example 1 Polyethersulfone was melt-kneaded using a twin-screw kneader at a resin temperature of 330 ° C., melt-extruded from a die, and a 0.2 mm thick film was prepared and used.

Each characteristic was measured as follows. Film appearance: The film appearance was visually judged.
A sample with good smoothness was marked with "O", and a sample with poor smoothness was marked with "x". Transparency: HAZE was measured according to ASTM-D1003. Dimensional stability during heating: Measurement was performed at a temperature rising rate of 5 ° C./min from 20 ° C. to 200 ° C. under a load of 5 g using TMA / SS120C (manufactured by Seiko Instruments Inc.). The dimensional change in the sample (length 10 mm) during that time was measured. Table 1 shows the composition and the results of each measurement.

[0019]

[Table 1]

[0020]

According to the present invention, a plastic film having excellent surface smoothness and transparency, as well as excellent heat resistance such as shape retention at high temperatures and low dimensional change during heating is provided. The heat-resistant film is useful as an optical substrate or the like in the field of optoelectronics.

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Claims (2)

[Claims] 1. A heat-resistant film comprising a resin composition comprising a thermoplastic resin having a glass transition point of 100 ° C. or higher and a layered compound. 2. A heat-resistant film obtained by laminating the resin composition according to claim 1 on at least one surface of a film made of polyethersulfone.