JP2003277630A - Heat-resistant transparent resin molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat-resistant transparent resin molded product usable for transparent electrode plates made of a resin in a portable display or transparent circuit substrates, or the like, in electrical and electronic equipment and having a low coefficient of linear expansion and high rigidity and excellent transparency. <P>SOLUTION: The molded product is obtained by including flaky boehmite having ≥1 μm average diameter and ≥10 aspect ratio in a heat-resistant resin having 1.650±0.015 refractive index such as a polyethersulfone so as to provide ≥80% orientation ratio in the planar direction of the boehmite. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant transparent resin molding suitable for use as an image display body such as a liquid crystal display (LCD) and EL, a transparent electronic component mounting substrate, and the like.

[0002]

2. Description of the Related Art Image display devices represented by LCDs and ELs (hereinafter referred to as "displays") are used in various fields including televisions and computers, and have made remarkable progress. . These displays, which play an important role in man-machine interfaces, are expected to become even more popular with the advent of the multimedia era, and are expected to spread significantly especially for mobile phones, PHS, and other mobile terminals. Has been done. For these portable displays, there is a strong demand for weight reduction, and thin resin transparent electrode plates are required. However, due to lack of rigidity, existing transparent resins lack heat resistance when manufacturing transparent electrodes such as ITO. The yield is poor. Therefore, a heat-resistant transparent resin having higher rigidity has been demanded.

Further, an opaque substrate is usually used as a substrate for mounting electronic components essential to all electric and electronic devices. However, as the circuit is highly integrated, a multilayer type substrate is often used. Has become. A transparent substrate is suitable for positioning and inspection during the production of this multilayer substrate, and a lightweight and transparent circuit substrate having the solder heat resistance and the low coefficient of linear expansion required for ordinary substrate production is desired.

[0004]

As a method for improving the heat resistance and rigidity of a resin, it is known to add an inorganic substance or a heat resistant organic filler. It is also known that a transparent composite resin composition can be obtained by including a filler having a refractive index substantially matching the refractive index of the transparent resin.

However, since the crystalline inorganic compound used as a usual filler has a different refractive index depending on the crystal axis, sufficient transparency cannot be obtained even if a filler having a refractive index substantially matching that of the resin is used. It was

It is also known that a transparent resin composition can be obtained by incorporating a filler having a particle diameter of about half a wavelength of visible light or less. Such ultrafine particles are incorporated into the resin. Since it is difficult to disperse uniformly and aggregates of the filler remain, it is difficult to obtain a stable and transparent resin composition. In addition, such ultrafine particles cannot be expected to improve the rigidity.

The present invention is to apply a heat-resistant transparent resin molding having a low coefficient of linear expansion and high rigidity and excellent transparency.

[0008]

The present invention has a refractive index of 1.6.
50 ± 0.015 heat resistant resin with an average diameter of 1 μm or more,
A heat-resistant transparent resin molded product, characterized in that flaky boehmite having an aspect ratio of 10 or more is contained so that the orientation ratio in the plane direction of the boehmite is 80% or more.

The heat-resistant resin used in the present invention is not particularly limited as long as it has heat resistance, but it is preferably a resin having good transparency. Specific examples of such resins include polyethylene terephthalate (PET), polyethylene naphthalate (PEN),
Examples thereof include polyarylate, polyimide, polyetherimide, polysulfone, polyethersulfone, and epoxy resin. Moreover, the resin which blended these resins can also be used. Polyether sulfone is particularly preferably used as the heat resistant resin in the present invention.

The heat-resistant resin used in the present invention has a refractive index of 1.650 ± 0.015, more preferably 1.650 ± 0.010. If the refractive index of the resin is out of this range, the transparency tends to decrease. The transparency of the resin includes light transmittance (JIS K-736).
(Measured according to 1) is preferably 80% or more,
More preferably, it is 90% or more.

The flaky boehmite used in the present invention has an average diameter of 1 μm or more and an aspect ratio of 10.
The above is used. The average diameter is preferably 1
10 to 10 μm, and more preferably 2 to 10 μm. If the average diameter is smaller than 1 μm, the expression of the performance is insufficient in the linear expansion coefficient and the rigidity, and thus the heat resistance is poor. If the average diameter exceeds 10 μm, the surface roughness of the resin molded body tends to be large and the transparency tends to be slightly lowered. However, in the present invention, it is also possible to use those having an average diameter of more than 10 μm.

The aspect ratio of the flaky boehmite used in the present invention is 10 or more, preferably 15 or more. By using a high aspect ratio,
The coefficient of linear expansion can be suppressed, and the rigidity and heat resistance can be improved. Further, by using a material having a high aspect ratio, it is possible to increase the orientation rate of the boehmite in the surface direction in the resin molded body. The upper limit of the aspect ratio is not particularly limited, but generally 100 or less is used.

The average diameter of boehmite in the present invention can be measured by a laser diffraction type particle size distribution meter. The aspect ratio can be measured by SEM observation.

The flaky boehmite used in the present invention can be synthesized by a known method. For example,
Japanese Patent Application Laid-Open No. 60-46923 discloses that a predetermined crystal axis (a
A boehmite having a hexagonal plate shape elongated in the (axial) direction is disclosed. Further, Japanese Patent Laid-Open No. 5-279019 discloses a boehmite having a polygonal plate shape such as a square plate shape. Furthermore, JP-A-4-5010
Japanese Patent Publication 5 discloses boehmite having a spindle shape, a needle shape, a scale shape, a hexagonal plate shape, and a square (square) plate shape. Further, JP-A-2000-86235 and JP-A-2001-261331 also disclose a method for producing plate boehmite having a high aspect ratio.

In the present invention, the flaky boehmite is contained in the heat-resistant resin so that the plane orientation of the boehmite is 80% or more. By containing boehmite in such an orientation rate, high transparency can be obtained. When the orientation ratio is less than 80%, the orientation of boehmite in the resin becomes random, and it becomes impossible to obtain high transparency in the present invention.

The orientation rate of boehmite in the present invention can be determined by measuring the inclination of the surface of boehmite present in the cross section perpendicular to the extrusion or stretching direction of the resin molding. Specifically, it can be calculated according to the following formula (1) from a scanning electron microscope (SEM) observation photograph of the cross section of the resin molded body.

Orientation rate = 100 × A / B (1) where A is 0 or less than 45 degrees when the angle between the surface of the boehmite at each observation point and the surface of the molded body is 45 degrees or more. This is a value obtained by calculating the sum of all measurement points with the case being 1, and B indicates the number of all measurement points.

FIG. 1 is a schematic diagram for explaining the angle formed by the surface of the boehmite and the surface of the molded body. In FIG. 1, 1 indicates the surface of the molded body, and 2 indicates the surface of boehmite. Reference numeral 3 denotes a surface parallel to the surface 1 of the molded body, where the angle α formed by this surface 3 and the surface 2 of boehmite is 45 degrees or more is 0, and 1 is less than 45 degrees. As above, the value of A is calculated.

From the SEM observation photograph of the cross section of the resin molding,
As a specific method of measuring the value of A, in the SEM observation photograph, the angle α of the boehmite surface is sequentially measured at 50 or more points in the thickness direction of the cross section of the molded body for each area of the average diameter of the boehmite. To do. If it is difficult to measure at 50 points or more due to the thin thickness of the molded body, measure at multiple points in the thickness direction of the cross section of the molded body at different positions, for a total of 5
Measure until more than 0 points. The reason why the measurement points are sequentially changed in the thickness direction of the cross section is that the inclination of the surface of the boehmite tends to be different in the thickness direction of the cross section. That is, the degree of orientation of boehmite is different between the central portion of the cross section and the upper and lower end portions thereof. Therefore, when the molded body has a large thickness, it is preferable to sample the entire region substantially uniformly in the thickness direction of the cross section. In the cross-section observation photograph of the SEM, when the boehmite surface faces the front and the boehmite surface cannot be observed from the side, the cross section orthogonal to the observed cross section was observed again by the SEM and measured.

In the present invention, the orientation ratio in the plane direction of boehmite is set to 80% or more. As a method of increasing the orientation ratio of boehmite in the plane direction, it is effective to impart a stretching effect of a certain degree or more in parallel with the plane direction. For example, in the case of an extruder, when the sheet is produced by stretching after extrusion, the sheet thickness is 1/5 or less of the lip interval of the extruder,
Preferably, the thickness of the molded product before and after pressing is adjusted to 1/3 or less, preferably 1/5 or less by adjusting the temperature and the press pressure in the heating press to obtain the product of the present invention. Obtainable. Even in an injection molding machine, pressing can be performed at the time of molding with a special mold, but normally, the orientation rate of the present invention is obtained by controlling the resin temperature, injection speed, and injection pressure according to the mold. be able to. Specifically, it cannot be specified unconditionally because it depends on the molding machine and the mold, but in general, the slower the injection speed within the range that does not hinder the molding, the easier the orientation, and the higher the injection speed, the lower the orientation rate. It is in.

The heat-resistant transparent resin molding of the present invention is a resin molding having good transparency. The light transmittance is 7
It is preferably at least 5%, more preferably at least 80%. Further, the compounding amount of boehmite is preferably 40% by weight or less in terms of total solid content concentration. If it exceeds 40% by weight, the fluidity of the resin is lowered, it becomes difficult to maintain the orientation rate, and the surface roughness is lowered and the transparency tends to be lowered.

The thickness of the heat-resistant transparent resin molding of the present invention is
Although it is appropriately selected depending on the application, it is preferably thin from the viewpoint of transparency. Further, in consideration of productivity, the thickness of the heat-resistant transparent resin molding of the present invention is 0.01
The thickness is preferably ˜1.5 mm, more preferably 0.25 to 1 mm.

In the present invention, when boehmite is agglomerated in the resin, the thickness of the molded body tends to vary, and the internal scattering causes the transparency to deteriorate. In order to improve the dispersibility of boehmite, it is preferable to surface-treat the surface of boehmite with a silicate compound or a titanate compound.

The production of the resin composition for producing the molded article of the present invention is not particularly limited, and a conventionally known method can be used. For example, in the case of a thermoplastic resin, the resin and boehmite are tumbled, if necessary.
The mixture can be preliminarily mixed using a ribbon mixer or the like, and the mixture can be melt-kneaded using a single-screw or twin-screw extruder. Alternatively, a kneading device that can separately supply the resin and the boehmite in a fixed amount may be used to melt-knead the boehmite and the resin while mixing them. Further, other Banbury mixers, rolls, various kneaders and the like can be appropriately selected and used according to the resin used.

The method of molding the resin molding of the present invention is
There is no particular limitation as long as the orientation rate of the boehmite in the resin in the plane direction can be 80%. For example, conventionally known molding methods such as heating rolls, pressing, injection molding, and extrusion can be widely used.

Further, the resin molded product of the present invention may contain additives such as an antioxidant, a heat stabilizer, a release agent and an ultraviolet absorber within a range that does not impair the effects of the present invention.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to specific examples, but the present invention is not limited to the following examples.

The average diameter of boehmite used in the following examples and comparative examples was measured by a laser diffraction type particle size distribution meter. The aspect ratio of boehmite was measured by SEM observation.

(Example 1) Using a twin-screw extruder (TEX44 manufactured by Japan Steel Works, Ltd.), polyether sulfone (Sumika Excel 3600G manufactured by Sumitomo Chemical Co., Ltd., refractive index (measured according to JIS K-7142) (Measured value) 1.65) and 20% by weight of flaky boehmite having an average diameter of 5.3 μm and an aspect ratio of 30 produced according to JP-A-2000-86235 were kneaded by a side feed method. At this time, the cylinder temperature was 340 ° C. and the screw rotation speed was 150 rpm. The resin composition was extruded from a die having a diameter of 3.5 mm, cooled, and then strand-cut to obtain pellets of the resin composition. Using this pellet, each test piece in accordance with JIS was molded by an injection molding machine (FS-150N manufactured by Nissei Plastic Industry Co., Ltd., cylinder temperature 350 ° C, mold temperature 140 ° C). Using this test piece, bending strength (JIS K7203) was determined as an evaluation of rigidity, and deflection temperature under load (load 1.8MP was evaluated as an evaluation of heat resistance.
a, JIS K7191)) was measured.

A sample for measuring the total light transmittance (JIS K7361) was prepared as follows. Using the above resin composition pellets, a sheet extruder was drawn from a T-die (340 ° C.) having a lip gap of 3 mm to have a thickness of 2
A 50 μm sheet was molded. Then, in order to make the surface roughness uniform, a glossy polyimide film is laminated on both sides of the sheet, and the thickness is 200 μm by a vacuum press at 340 ° C.
What was rolled to m was used as the measurement sample. Further, using this sheet, the orientation rate was measured by the above method, and the linear expansion coefficient was measured by TMA (thermomechanical analyzer).

(Example 2) Using the resin composition of Example 1, an injection molding machine (Sumitomo Heavy Industries Ltd. Minimat M2) was used.
6. At a cylinder temperature of 350 ° C. and a mold temperature of 140 ° C., a mold having a thickness of 0.6 mm and a size of 50 mm × 90 mm was molded with an injection time of 0.46 seconds. The total light transmittance and orientation of this product were measured.

(Example 3) Molding was carried out in the same manner as in Example 2 with an injection time of 0.35 seconds, and the total light transmittance and orientation ratio were measured.

Comparative Example 1 Molding was carried out in the same manner as in Example 2 with an injection time of 0.21 seconds, and the total light transmittance and orientation ratio were measured.

(Comparative Example 2) Using the resin composition of Example 1, as in Example 1, the sheet was stretched from a T-die having a lip gap of 0.75 mm and a thickness of 250 μm.
Sheet was molded. Then, in order to make the surface roughness uniform, glossy polyimide films were laminated on both sides of the sheet and rolled to a thickness of 200 μm by a vacuum press at 340 ° C. to obtain a sample for measuring total light transmittance. The orientation ratio was also measured by the above method using this sheet.

Comparative Example 3 A JIS-compliant test piece and a sheet having a thickness of 200 μm were produced in the same manner as in Example 1 except that the filler boehmite was not added. The bending strength (JI
SK7203), deflection temperature under load (load 1.8MP
a, JIS K7191)), total light transmittance, linear expansion coefficient, and orientation rate were measured.

Table 1 shows the above measurement results.

[0037]

[Table 1]

As is clear from the results shown in Table 1, Examples 1 to 10 in which the plane orientation of boehmite was 80% or more
No. 3 has a higher total light transmittance than Comparative Examples 1 and 2. Therefore, it can be seen that the transparency is improved by adjusting the plane orientation of boehmite to 80% or more according to the present invention.

(Comparative Example 4) Using a twin-screw extruder (TEX44 manufactured by Japan Steel Works, Ltd.), an average diameter produced according to Japanese Patent Application No. 2000-83912 and polyether sulfone (Sumitake Chemical Co., Ltd. Sumika Excel 3600G). Flaky boehmite 2 with 0.8 μm and aspect ratio 12
0% by weight was kneaded by a side feed method. At this time, the cylinder temperature was 340 ° C and the screw rotation speed was 150r.
It was pm. It was extruded from a die having a diameter of 3.5 mm, cooled and strand-cut to obtain pellets. Using this pellet, a sample for measuring bending strength, deflection temperature under load, total light transmittance, linear expansion coefficient, and orientation rate was prepared and evaluated in the same manner as in Example 1.

(Comparative Example 5) Using a twin-screw extruder (TEX44 manufactured by Japan Steel Works, Ltd.), a polyether sulfone (Sumika Excel 3600G manufactured by Sumitomo Chemical Co., Ltd.), a plate having an average diameter of 3.3 μm and an aspect ratio of 6 was used. Boehmite 2
0% by weight was kneaded by a side feed method. At this time, the cylinder temperature was 340 ° C and the screw rotation speed was 150r.
It was pm. It was extruded from a die having a diameter of 3.5 mm, cooled and strand-cut to obtain pellets. Using this pellet, a sample for measuring bending strength, deflection temperature under load, total light transmittance, coefficient of linear expansion, and orientation ratio was prepared and evaluated in the same manner as in Example 1.

The evaluation results are shown in Table 2.

[0042]

[Table 2]

From the comparison between Comparative Examples 4 and 5 shown in Table 2 and Example 1 shown in Table 1, by using the boehmite having the average diameter and the aspect ratio according to the present invention, the linear expansion coefficient is low and the rigidity is high. It can be seen that a transparent resin molding having excellent transparency can be obtained.

[0044]

According to the present invention, a heat-resistant transparent resin molding having a low expansion coefficient and high rigidity and excellent transparency can be obtained. Therefore, the heat-resistant transparent resin molded product of the present invention is used for a transparent resin electrode plate having a small thickness required for a portable display, a transparent circuit board for mounting electronic components in electric / electronic devices, and the like. be able to.

[Brief description of drawings]

FIG. 1 is a schematic diagram for explaining an orientation ratio in the surface direction of boehmite in the present invention.

[Explanation of symbols]

1 ... Surface of molded body 2 ... Boehmite side 3 ... A surface parallel to the surface of the molded body

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Claims (3)

[Claims] 1. A flaky boehmite having an average diameter of 1 μm or more and an aspect ratio of 10 or more is applied to a heat-resistant resin having a refractive index of 1.650 ± 0.015, and the orientation ratio in the plane direction of the boehmite is 8
A heat-resistant transparent resin molded product, characterized in that the content is 0% or more. 2. The heat-resistant transparent resin molding according to claim 1, wherein the heat-resistant resin is polyether sulfone. 3. The heat-resistant transparent resin molding according to claim 1, which is a sheet-shaped molding.