JP5865953B2 - Method for producing poly (meth) acrylimide film - Google Patents

Description

The present invention relates to a method for producing a poly (meth) acrylimide film. More specifically, the present invention relates to a method for producing a poly (meth) acrylimide film having excellent surface smoothness, transparency, and appearance and having a small retardation.

2. Description of the Related Art In recent years, touch panels that are installed on image display devices such as liquid crystal displays, plasma displays, and electroluminescent displays and that can be input by touching with a finger or a pen while viewing the display have become widespread.

Conventionally, a display base plate of a touch panel and a transparent conductive substrate meet the required characteristics such as heat resistance, dimensional stability, high transparency, high surface hardness, and high rigidity. Have been used. On the other hand, glass has problems such as low impact resistance and easy cracking, low workability, difficult handling, high specific gravity and heavy, and difficulty in meeting the demands for curved display and flexibility. Therefore, materials that replace glass have been actively studied, and the surface of a transparent resin film substrate such as triacetyl cellulose, polyethylene terephthalate, polycarbonate, polymethyl methacrylate, and norbornene-based polymer has excellent surface hardness and scratch resistance. Many hard coat laminated | multilayer films which formed the hard coat are proposed (for example, patent document 1). However, its heat resistance and dimensional stability are insufficient.

Especially for the replacement of the transparent conductive substrate, when forming the transparent conductive film, the process temperature is kept high to increase the crystallinity of the transparent conductive film and reduce the surface resistance. The process temperature cannot be raised because it is insufficient; the thin film transistor cannot be formed on the transparent conductive laminated film because the heat resistance of the transparent resin film substrate is insufficient; Adoption of hard coat laminated film is not progressing. At present, glass is exclusively used for the transparent conductive substrate.

Then, this inventor considered using poly (meth) acrylimide as a transparent resin film base material. Poly (meth) acrylimide is colored from light yellow to reddish brown by introducing the heat resistance and dimensional stability of polyimide resin while maintaining the high transparency, high surface hardness and high rigidity of acrylic resin. It is a thermoplastic resin that has improved the drawback of being made, and is disclosed in Patent Document 2, for example. However, a normal T-die extrusion method could not obtain a poly (meth) acrylimide film excellent in surface smoothness, transparency and appearance. Patent Document 3 discloses “an acrylic film having a thin film thickness and good die line, surface roughness and film wrinkle and a method for producing the same”. Since poly (meth) acrylimide also has characteristics as acrylic, the present inventor tried to apply the technique of Patent Document 3, but poly (meth) acrylimide excellent in surface smoothness, transparency and appearance as well. A film could not be obtained.

JP 2013-208896 A Special table 2011-519999 gazette JP 2009-292877 A

The subject of this invention is providing the method of manufacturing the poly (meth) acrylimide film which is excellent in surface smoothness, transparency, and external appearance, and has small retardation.

As a result of diligent research, the present inventor has supplied a molten film of poly (meth) acrylimide between the rotating or circulating first mirror body and the rotating or circulating second mirror body. It has been found that the above-mentioned problem can be achieved by controlling the surface temperature of the first mirror body and the surface temperature of the second mirror body to a specific range when pressing.

That is, the present invention is a method for producing a poly (meth) acrylimide film,
(A) A step of continuously extruding a molten film of poly (meth) acrylimide from a T die using an apparatus including an extruder and a T die;
(B) supplying and pressing the molten film of poly (meth) acrylimide between the first mirror body that rotates or circulates and the second mirror body that rotates or circulates;
Wherein (C) the surface temperature of the first mirror body is 100 to 200 ° C .;
(D) The surface temperature of the second mirror body is 20 to 200 ° C .;
It is the method characterized by this.

The second invention of the present invention is a method for producing a poly (meth) acrylimide film,
(A) A step of continuously extruding a molten film of poly (meth) acrylimide from a T die using an apparatus including an extruder and a T die;
(B) supplying and pressing the molten film of poly (meth) acrylimide between a rotating mirror surface roll and a mirror belt circulating along the outer peripheral surface of the mirror surface roll;
Wherein (C) the surface temperature of the mirror roll is 100 to 200 ° C .;
(D) The surface temperature of the mirror belt is 20 to 200 ° C .;
It is the method characterized by this.

The third invention of the present invention is the method according to the first invention, wherein the first mirror body is a mirror roll; and the second mirror body is a mirror roll. It is.

A fourth invention of the present invention is a poly (meth) acrylimide film obtained by the method according to any one of the first to third inventions.

5th invention of this invention is use as an image display apparatus member of the film as described in 4th invention.

6th invention of this invention is an image display apparatus member containing the film as described in 4th invention.

The poly (meth) acrylimide film obtained by the production method of the present invention is excellent in surface smoothness, transparency, and appearance. Further, the surface hardness and rigidity are high, and the color tone, heat resistance and dimensional stability are excellent. Furthermore, the retardation is small. Therefore, members of an image display device such as a liquid crystal display, a plasma display, and an electroluminescence display (including an image display device having a touch panel function and an image display device not having a touch panel function), for example, a display face plate of a touch panel and a transparent conductive material It can be suitably used as a substrate.

The manufacturing method of this invention is a manufacturing method of a poly (meth) acrylimide film, Comprising: The apparatus provided with (A) extruder and T die, The molten film of poly (meth) acrylimide is used from T die. Continuously extruding.

Poly (meth) acrylimide is colored from light yellow to reddish brown by introducing the characteristics of the heat resistance and dimensional stability of polyimide resin while maintaining the characteristics of acrylic resin with high transparency, high surface hardness and high rigidity. This resin improves the above-mentioned drawback and has thermoplasticity. In the present specification, poly (meth) acrylimide means polyacrylimide or polymethacrylamide.

The poly (meth) acrylimide used in the production method of the present invention is not limited, and any poly (meth) acrylimide can be used. From the viewpoint of extrusion load and melt film stability, poly (meth) The melt mass flow rate of acrylimide (measured in accordance with ISO 1133 under the conditions of 260 ° C. and 98.07 N) is preferably 0.1 to 20 g / 10 minutes, and more preferably 0.5 to 10 g / 10 minutes.

In addition, for the purpose of using the obtained poly (meth) acrylimide film for a display face plate of a touch panel or a transparent conductive substrate, poly (meth) acrylimide is less colored and has a yellowness index (measured according to JIS K 7105: 1981). Those of 3 or less are preferred. More preferably, it is 2 or less, More preferably, it is 1 or less.

Further, the glass transition temperature of poly (meth) acrylimide is preferably 150 ° C. or higher. More preferably, it is 170 degreeC or more.

Examples of commercially available poly (meth) acrylimide include “ACRYMID TT70 (trade name)” manufactured by Evonik.

In addition, the poly (meth) acrylimide may be a thermoplastic resin other than poly (meth) acrylimide; a pigment, an inorganic filler, an organic filler, a resin filler; a lubricant, an oxidation, if desired, as long as the object of the present invention is not violated. An additive such as an inhibitor, a weather resistance stabilizer, a heat stabilizer, a release agent, an antistatic agent, and a surfactant may be further included. The compounding quantity of these arbitrary components is about 0.01-10 mass parts normally, when poly (meth) acrylimide is 100 mass parts.

Any extruder can be used, and examples thereof include a single-screw extruder, a same-direction rotating twin-screw extruder, and a different-direction rotating twin-screw extruder.

Further, in order to suppress deterioration during film formation of poly (meth) acrylimide, it is also one of preferred embodiments that the inside of the extruder is purged with nitrogen.

Furthermore, since poly (meth) acrylimide is a highly hygroscopic resin, it is preferably dried before being used for film formation. It is also one of preferred embodiments that the poly (meth) acrylimide dried by the dryer is directly transported from the dryer to the extruder and charged. The set temperature of the dryer is preferably 100 to 150 ° C.

Arbitrary things can be used as said T die, For example, a manifold die, a fish tail die, a coat hanger die, etc. can be mention | raise | lifted.

The temperature of the T die is preferably set to at least 260 ° C. or higher in order to stably perform the process of continuously extruding a poly (meth) acrylimide molten film. More preferably, it is 270 degreeC or more. In order to suppress the deterioration of poly (meth) acrylimide, the temperature of the T die is preferably set to 350 ° C. or lower.

Further, the ratio (R / T) between the lip opening (R) and the thickness (T) of the resulting poly (meth) acrylimide film is preferably 5 or less from the viewpoint of preventing the retardation from increasing. The following is more preferable. Further, the ratio (R / T) is preferably 1 or more, more preferably 1.1 or more, from the viewpoint of preventing the extrusion load from becoming excessive.

In the production method of the present invention, (B) a molten film of the poly (meth) acrylimide is supplied and fed between a rotating or circulating first mirror body and a rotating or circulating second mirror body. And pressing.

As said 1st mirror surface body, a mirror surface roll, a mirror surface belt, etc. can be mention | raise | lifted, for example. As said 2nd mirror surface body, a mirror surface roll, a mirror surface belt, etc. can be mention | raise | lifted, for example.

The mirror roll is a roll having a mirror-finished surface, and may be made of metal, ceramic, silicon rubber, or the like. Further, the surface of the mirror roll can be subjected to chrome plating, iron-phosphorus alloy plating, hard carbon treatment by PVD method or CVD method, etc. for the purpose of protection from corrosion and scratches.

The mirror belt is a seamless belt made of a normal metal whose surface is mirror-finished. For example, the mirror belt is circulated between a pair of belt rollers. Further, the surface of the mirror belt can be subjected to chrome plating, iron-phosphorus alloy plating, hard carbon treatment by PVD method or CVD method for the purpose of protection from corrosion and scratches.

The mirror finish is not limited and can be performed by any method. For example, by polishing using fine abrasive grains, the arithmetic average roughness (Ra) of the surface of the mirror body is preferably 100 nm or less, more preferably 50 nm or less, and the ten-point average roughness (Rz) is preferably The method of making it 500 nm or less, More preferably 250 nm or less can be mention | raise | lifted.

Although not intended to be bound by theory, the surface temperature of the poly (meth) acrylimide film excellent in surface smoothness, transparency, and appearance was obtained at 100 to 200 ° C. by the method of the present invention. By pressing a molten film of poly (meth) acrylimide with the first mirror body and the second mirror body having a surface temperature of 20 to 200 ° C., the first mirror body and the second mirror body are highly advanced. It is considered that the smooth surface state is transferred to the film, and defective portions such as dies are corrected.

In order to perform the transfer of the surface state satisfactorily, the surface temperature of the first mirror body is at least 100 ° C. or higher, preferably 120 ° C. or higher, more preferably 140 ° C. or higher. On the other hand, the surface temperature of the first mirror body is 200 ° C. or less, preferably 160 ° C. or less, in order to prevent appearance defects (peeling marks) due to peeling from the first mirror body from appearing on the film.

The surface temperature of the second mirror body is at least 20 ° C. or higher, preferably 60 ° C. or higher, more preferably 100 ° C. or higher so that the surface state can be transferred satisfactorily. On the other hand, the surface temperature of the second mirror body is 200 ° C. or less, preferably 160 ° C. or less, in order to prevent appearance defects (peeling marks) due to peeling from the second mirror body on the film.

The surface temperature of the first mirror body is preferably higher than the surface temperature of the second mirror body. This is because the film is held in the first mirror body and sent to the next transfer roll.

An example of an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a conceptual diagram showing an example of an embodiment of the production method of the present invention. The molten film 2 of poly (meth) acrylimide continuously extruded from the T-die 1 is supplied and fed between the rotating mirror roll 3 and the mirror belt 4 circulating along the outer peripheral surface of the mirror roll 3. By being pressed, the highly smooth surface state of the mirror roll 3 and the mirror belt 4 is transferred to the film, and defective portions such as die lines are corrected, and the film has excellent surface smoothness, transparency, and appearance. become.

The mirror surface roll 3 is a roll whose surface is mirror-finished, and may be made of metal, ceramic, silicon rubber, or the like. Further, the surface of the mirror roll can be subjected to chrome plating, iron-phosphorus alloy plating, hard carbon treatment by PVD method or CVD method, etc. for the purpose of protection from corrosion and scratches.

The mirror belt 4 is a seamless belt, usually made of metal, having a mirror-finished surface, and is circulated between a pair of belt rollers 5. The surface of the mirror belt 4 can be subjected to chrome plating, iron-phosphorus alloy plating, hard carbon treatment by PVD method or CVD method, etc. for the purpose of protection from corrosion and scratches.

When the mirror belt 4 is pressed against the mirror roll 3, it circulates along the outer peripheral surface of the mirror roll 3. Therefore, by using the mirror roll 3 and the mirror belt 4, the molten film can be pressed by the surface, and the transfer of the surface state and the correction of the defective portion can be surely performed.

The pair of belt rollers 5 are usually suspended on a support base capable of finely adjusting the distance between the upper and lower sides in order to keep the mirror roll 3 and the mirror belt 4 parallel to each other at a high level. The tension of the mirror belt 4 can be adjusted by the distance between the pair of belt rollers 5.

The surface temperature of the mirror surface roll 3 is at least 100 ° C. or higher, preferably 120 ° C. or higher, more preferably 140 ° C. or higher so that the transfer of the surface state can be performed satisfactorily. On the other hand, the surface temperature of the mirror surface roll 3 is 200 ° C. or less, preferably 160 ° C. or less, in order to prevent appearance defects (peeling marks) due to separation from the mirror surface roll 3 from appearing on the film.

The surface temperature of the mirror belt 4 is at least 20 ° C. or higher, preferably 60 ° C. or higher, more preferably 100 ° C. or higher so that the transfer of the surface state can be performed satisfactorily. On the other hand, the surface temperature of the mirror belt 4 is 200 ° C. or less, preferably 160 ° C. or less, in order to prevent appearance defects (peel marks) due to peeling from the mirror roll 4 on the film.

The surface temperature of the mirror surface roll 3 is preferably higher than the surface temperature of the mirror surface belt 4. This is because the film is held by the mirror roll 3 and sent to the next transfer roll.

The thickness of the poly (meth) acrylimide film produced by the production method of the present invention is not particularly limited, and can be any thickness as desired. From the viewpoint of handleability of the poly (meth) acrylimide film produced by the production method of the present invention, it may be usually 20 μm or more, preferably 50 μm or more. From the viewpoint of economy, it may be usually 250 μm or less, preferably 150 μm or less. When the poly (meth) acrylimide film produced by the production method of the present invention is used as a display face plate, it is usually 100 μm or more, preferably 200 μm or more, more preferably 300 μm or more from the viewpoint of maintaining rigidity. . Further, from the viewpoint of meeting the demand for thinning of the image display device, it may be usually 1500 μm or less, preferably 1200 μm or less, more preferably 1000 μm or less.

EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these.

Measurement method (a) Surface appearance:
The film surface was visually observed while being applied with various incident angles of the fluorescent light, and evaluated according to the following criteria.
A: There is no wave or scratch on the surface. There is no cloudiness even when looking at the light up close.
○: Slight swells and scratches are observed on the surface when viewed closely. There is a slight cloudiness when I see light up close.
Δ: Waviness and scratches can be observed on the surface. There is also a cloudiness.
X: Many undulations and scratches can be observed on the surface. There is also a clear cloudiness.

(B) Total light transmittance:
According to JIS K 7361-1: 1997, it measured using the turbidimeter "NDH2000 (brand name)" of Nippon Denshoku Industries Co., Ltd.

(C) Haze:
According to JIS K 7136: 2000, it measured using the turbidimeter "NDH2000 (brand name)" of Nippon Denshoku Industries Co., Ltd.

(D) Pencil hardness:
According to JIS K 5600-5-4, it evaluated using the pencil "Uni (brand name)" of Mitsubishi Pencil Co., Ltd. on 200 g load conditions.

(E) Color tone:
According to JIS K 7105: 1981, a yellowness index (YI) was measured using a chromaticity meter “SolidSpec-3700 (trade name)” manufactured by Shimadzu Corporation.

(F) Linear expansion coefficient (thermal dimensional stability):
It measured according to JISK7197: 1991. A thermomechanical analyzer (TMA) “EXSTAR6000 (trade name)” manufactured by Seiko Instruments Inc. was used. The test piece was 20 mm long and 10 mm wide, and the film was collected so that the machine direction (MD) of the film was the vertical direction of the test piece. Conditioning of the test piece was performed at a temperature of 23 ° C. ± 2 ° C. and a relative humidity of 50 ± 5% for 24 hours. For the purpose of measuring the dimensional stability as a physical property value of the film, the condition adjustment at the maximum measurement temperature was not performed. . The distance between chucks was 10 mm, and the temperature program was a program in which the temperature was maintained at 20 ° C. for 3 minutes, and then the temperature was increased to 270 ° C. at a temperature increase rate of 5 ° C./min. The linear expansion coefficient was calculated from the obtained temperature-test piece length curve as a low temperature side temperature of 30 ° C. and a high temperature side temperature of 200 ° C.

(G) Retardation:
It measured using the phase difference measuring apparatus "KOBRA-WR (brand name)" by the parallel Nicol rotation method of Oji Scientific Instruments.

Raw materials used (A) Poly (meth) acrylimide:
(A-1) Poly (meth) acrylimide “ACRYMID TT70 (trade name)” manufactured by Evonik.

Example 1
Using the above (A-1), using a 50mm extruder (with L / D = 29, CR = 1.86 W flight screw), T die with die width of 680mm, mirror roll and mirror belt From the extruder, the temperature setting of the T die C1 / C2 / C3 / AD / D1 to D6 = 280/300/320/320/320 to 320 ° C., the lip opening of the T die 0.5 mm, the screw rotation speed 90 rpm, A film having a thickness of 250 μm was formed under the conditions of a mirror roll surface temperature of 140 ° C., a mirror belt surface temperature of 120 ° C., a mirror belt pressure of 1.4 MPa, and a take-off speed of 5.6 m / min. The test of said (i)-(g) was done about the obtained film. The results are shown in Table 1.

Examples 2-5
All operations were performed in the same manner as in Example 1 except that the mirror roll surface temperature and the mirror belt surface temperature were changed as shown in Table 1. The results are shown in Table 1.

Comparative Examples 1-4
All operations were performed in the same manner as in Example 1 except that the mirror surface temperature and the mirror belt surface temperature were changed as shown in Table 2. The results are shown in Table 2.

Example 6
Using the above (A-1), equipped with a 50 mm extruder (with a W flight screw with L / D = 29, CR = 1.86), a T die with a die width of 680 mm, a first mirror roll and a second mirror roll Set the temperature of the T die from the extruder C1 / C2 / C3 / AD / D1 to D6 = 280/300/320/320/320 to 320 ° C., the lip opening of the T die 0.5 mm, screw A film having a thickness of 250 μm is formed under the conditions of a rotation speed of 90 rpm, a first mirror roll surface temperature of 140 ° C., a second mirror roll surface temperature of 40 ° C., a press between the mirror rolls of 1.4 MPa, and a take-off speed of 5.6 m / min. did. The test of said (i)-(g) was done about the obtained film. The results are shown in Table 1.

Example 7
All operations were performed in the same manner as in Example 3 except that the take-up speed was 2.6 m / min and the film thickness was changed to 550 μm. The results are shown in Table 2.

Example 8
All operations were performed in the same manner as in Example 6 except that the take-up speed was 2.6 m / min and the film thickness was changed to 550 μm. The results are shown in Table 2.

The poly (meth) acrylimide film obtained by the production method of the present invention is excellent in surface smoothness, transparency and appearance. Further, the surface hardness is high, and the color tone, heat resistance, and dimensional stability are excellent. Furthermore, the retardation is small. On the other hand, Comparative Examples 1 and 2 have insufficient surface conditions. Transparency, dimensional stability, and retardation are also inferior to the examples. In Comparative Examples 3 and 4, peeling marks accompanying peeling with the mirror surface appeared on the film, and the appearance was remarkably poor. Therefore, the evaluation of (b) to (g) was omitted.

It is a conceptual diagram which shows an example of the embodiment of the manufacturing method of this invention.

1: T die 2: Molten film 3: Mirror roll 4: Mirror belt 5: A pair of belt rollers

Claims (8)

A method for producing a poly (meth) acrylimide film,
(A) A step of continuously extruding a molten film of poly (meth) acrylimide from a T die using an apparatus including an extruder and a T die;
(B) supplying and pressing the molten film of poly (meth) acrylimide between the rotating or circulating first mirror body and the rotating or circulating second mirror body; and pressing; ,
(E) A step of holding the film in the first mirror body and feeding it to the next transfer roll;
Wherein (C) the surface temperature of the first mirror body is 100 to 200 ° C .;
(D) the surface temperature of the second mirror body is 20 to 200 ° C .; and
(F) making the surface temperature of the first mirror body higher than the surface temperature of the second mirror body;
A method characterized by.
The first mirror body is a mirror roll;
And the second mirror body is a mirror roll;
The method of claim 1, wherein:
(F) making the surface temperature of the first mirror body 20 to 100 ° C. higher than the surface temperature of the second mirror body;
The method according to claim 1, wherein:
A method for producing a poly (meth) acrylimide film,
(A) A step of continuously extruding a molten film of poly (meth) acrylimide from a T die using an apparatus including an extruder and a T die;
(B) Supplying and pressing the molten film of poly (meth) acrylimide between a rotating mirror surface roll and a mirror surface belt circulating along the outer peripheral surface of the mirror surface roll; and pressing;
(E) A step of holding the film in the mirror roll and feeding it to the next transfer roll;
Wherein (C) the surface temperature of the mirror roll is 100 to 200 ° C .;
(D) the surface temperature of the mirror belt is 20 to 200 ° C .; and
(F) making the surface temperature of the mirror roll higher than the surface temperature of the mirror belt;
A method characterized by.
(F) making the surface temperature of the mirror surface roll 20 to 100 ° C. higher than the surface temperature of the mirror belt;
The method according to claim 4.
The glass transition temperature of the poly (meth) acrylimide is 150 ° C. or higher;
The method according to claim 1, wherein:
The ratio (R / T) of the lip opening (R) to the thickness (T) of the resulting poly (meth) acrylimide film is 1 to 5;
The method according to claim 1, wherein:
The manufacturing method of the image display apparatus member characterized by using the poly (meth) acrylimide film obtained by the method of any one of Claims 1-7.