JP6868337B2 - Film insert molded product and its manufacturing method - Google Patents

Description

The present invention relates to a film insert molded product preferably used for a front panel of a home electric appliance or the like, and a method for manufacturing the same.

Resin molded products are used as front panels in liquid crystal display devices such as displays for home appliances, mobile phones and audio equipment, and touch panel screens for automatic ticket vending machines. The surface of these front panels may be decorated with letters and patterns.
Conventionally, as a method of manufacturing such a resin molded product, there is a method of attaching a decorative film to a base sheet such as glass or a plastic plate.
For example, in Patent Document 1 below, a method of bonding a decorative film (design sheet) having character information and a base material sheet to a touch panel front plate is adopted.
This method is suitable for a flat base sheet, but has a problem that it cannot be applied to a three-dimensional base sheet.

Further, there is a film insert molding method in which a decorative film is placed as an insert film in a mold and a resin as a base material is injected (see, for example, Patent Document 3 below). This method can also be applied to resin molded products having a three-dimensional shape, but there is a problem that the decorative film (transfer film) stretches due to heat or the like during molding and transfer of the three-dimensional shape, causing distortion such as a pattern. ..

Therefore, Patent Document 2 below discloses a method of using a block copy in which distortion is corrected in advance when expressing a pattern such as a character or a pattern by using a film insert molding method.

WO06 / 095684 Japanese Unexamined Patent Publication No. 01-46754 Japanese Unexamined Patent Publication No. 2000-309033

However, it is difficult to accurately predict the strain generated in the molding process, and it cannot be said that a technique for accurately reproducing characters, patterns, etc. on the surface of a resin molded product having a three-dimensional shape has been established. In particular, since characters are composed of lines and are closely watched, there is a problem that distortion is more easily recognized than patterns.
Further, when a resin molded product is used as a front panel of an electric appliance or the like, it is difficult to visually recognize if the display such as an image or a liquid crystal is distorted.

Therefore, an object of the present invention is a film insert molded product having a three-dimensional shape, which reduces distortion, makes it easy to visually recognize displays such as images and liquid crystals, and can accurately reproduce characters, patterns, and the like. The purpose is to provide a manufacturing method.

The first embodiment of the present invention has a two-layer structure in which a base resin formed by injection molding is provided on the back surface side of the insert film on the front surface side, and has a flat surface portion and a standing wall portion whose periphery thereof is raised on the back surface side. This is a film insert molded product in which a transparent portion is provided on the flat surface portion and the periphery of the transparent portion is used as a decorative portion, and the phase difference of the transparent portion is 19 / 104π (phase difference 49 at a wavelength of 540 nm). It is a film insert molded product characterized by having a thickness of 3 nm) or less.

In the film insert molded product of the above form, since the phase difference of the transparent portion is low, distortion is small in this portion, and if this portion is used as a display screen for an image or a liquid crystal, it becomes easy to see. In addition, the distortion around it can be reduced, and the appearance is excellent.

The film insert molded product of the above-described form is preheated by using a heat insulating means and shaped to form an insert film, and the insert film is placed in a mold and the thermoplastic resin is placed in the mold. It can be manufactured by a manufacturing method including an injection molding step of filling.

As described above, in the shaping process of the insert film, when the insert film is formed, the preheating is performed by using the heat insulating means to shape the insert film, so that the phase difference becomes small and distortion occurs in the portion where the heat insulating means is used. It becomes difficult. Further, the phase difference of the film insert molded product molded by using the same can be reduced, and the film insert molded product having a transparent portion with small distortion can be manufactured. Further, when the decorative portion such as a character or a pattern is insulated, the distortion of the character or the pattern is reduced.

A film insert molded product according to an embodiment of the present invention is shown, (A) is a perspective view, and (B) is a sectional view. It is a figure which showed an example of the manufacturing method of the film insert molded article shown in FIG. 1, and showed the state which provided the decorative part in the insert film. It is a figure which shows an example of the manufacturing method of the film insert molded article shown in FIG. 1, and shows the position where the heat insulating material is arranged in the insert film provided with the decorative part in the shaping preheating process. It is the figure which showed an example of the manufacturing method of the film insert molded article shown in FIG. 1, and schematically showed the preheating process of shaping. FIG. 1 is a perspective view showing an example of a method for manufacturing a film insert molded product shown in FIG. 1 and showing a shaped insert film. An example of a method for manufacturing a film insert molded product shown in FIG. 1 is shown, (A) is a diagram schematically showing a mold for injection molding, and (B) describes a timing for injecting a resin in the case of injection compression molding. It is a figure for doing. It is a figure which showed the range which arranges the heat insulating means of the insert films 3 and 4 in an Example.

Hereinafter, a film insert molded product according to an embodiment of the present invention will be described with reference to the drawings. However, the present invention is not limited to this embodiment.

As shown in FIGS. 1 (A) and 1 (B), the film insert molded product 1 of the embodiment of the present invention is composed of the insert film 2 on the front surface side and the base resin 3 on the back surface side, and has a flat surface portion 4. It has a standing wall portion 5.

The thickness of the insert film 2 is not particularly limited, but is preferably 1 μm or more and 10 mm or less, and particularly preferably 150 μm or more and 350 μm or less. This range is preferable from the viewpoint of preventing tearing during shaping and maintaining rigidity after shaping.

As the insert film 2, for example, a resin film made of a resin composition such as polyethylene terephthalate, polymethylmethacrylate, and polycarbonate can be used.
The insert film 2 preferably has a total light transmittance of 90% or more, particularly 94% or more, and more preferably 98% or more.
In the present invention, the total light transmittance can be measured based on JIS K7361 or the like.
AF (anti-fingerprint), AR (anti-reflection, anti-reflection, low reflection), HC (hard code) functions and the like can be imparted to the surface of the insert film 2. These functions can be added by a conventional method.

The insert film 2 preferably has a glass transition temperature of 150 ° C. or lower, particularly 140 ° C. or lower, and more preferably 130 ° C. or lower. This range is preferable from the viewpoint of shortening the cycle in the shaping step described later.
The insert film 2 is not particularly limited, but has a coefficient of linear expansion of 30 ppm / K or more and 90 ppm / K or less, preferably 40 ppm / K or more and 80 ppm / K or less, and more preferably 50 ppm / K or more and 70 ppm / K. The range is as follows. If the linear expansion coefficient is set within the above range, the difference in the linear expansion coefficient between the insert film 2 and the base resin 3 in the film insert molded product 1 can be suppressed, and the difference in shrinkage ratio between the front and back surfaces of the film insert molded product 1 can be suppressed. It can be suppressed and the distortion of the film insert molded product 1 can be reduced.
In the present invention, the coefficient of linear expansion can be measured based on JIS K7197 or the like.

As shown in FIG. 2, the insert film 2 may be provided with a decorative portion 6. The decoration unit 6 may be decorated in any way, and examples thereof include solid coating, characters, and patterns. The portion other than the decorative portion 6 is a transparent portion. In the present embodiment, a rectangular transparent portion 7 that is not printed is provided, and a decorative portion 6 that is solidly painted in a round corner rectangular shape with an appropriate color is provided on the outside thereof. A part of the decorative portion 6 is transparently drawn so that the characters are exposed.
The decorative portion 6 can be formed by printing or laminating metal foil or the like. More specifically, it can be formed by printing such as screen printing, gravure printing, offset printing, transfer of a patterned or coated film, transfer of a metal leaf, and the like. Examples of this metal leaf include aluminum, gold, copper, stainless steel, and titanium, whereby a mirror surface can be formed.
The total light transmittance of the decorative portion 6 is preferably 10% or less, particularly 6% or less, and more preferably 2% or less.

The insert film 2 is shaped into a three-dimensional shape when it is molded into the film insert molded product 1.
In the present embodiment, the shape is shaped so as to have a standing wall portion 5 hanging from the periphery of the rectangular flat surface portion 4. The three-dimensional shape is not limited to this, and can be appropriately shaped into a three-dimensional shape according to the application.
The shaping is not particularly limited, but can be applied by compressed air molding or the like. More specifically, the insert film 2 is placed in a shaping mold in which the temperature is raised to near the glass transition temperature of the film after preheating. Then, the insert film 2 can be formed into a shaped shape by compressed air.

In the shaping preheating step, the insert film 2 can adjust the phase difference to 3 / 13π (phase difference 62.3 nm at a wavelength of 540 nm) or less by appropriately insulating the portion.
Examples of the method of heat insulating include a method of changing the heating temperature for each block and a method of using heat insulating means.
As the heat insulating means, a plate-shaped member made of a material having a low thermal conductivity can be used, and the heat conductivity is not particularly limited, but the thermal conductivity is 0.03 W / m · K or more and 0.20 W / m · K. Hereinafter, materials preferably 0.04 W / m · K or more and 0.18 W / m · K or less, more preferably 0.05 W / m · K or more and 0.15 W / m · K or less can be used. Specifically, from the viewpoint of excellent heat resistance, a heat insulating plate made of a silicic acid compound, glass fiber, or the like is preferable.
When performing the preheating process using a heat insulating material, the size of the heat insulating material covers the entire transparent part as shown in FIG. 2, and when printing characters or the like, also covers the character part. This is preferable from the viewpoint of reducing the distortion of the film insert molded product. Further, although the size of the heat insulating material is not limited, 65% or more and less than 100%, preferably 85% or more and 99% or less, with respect to the projected area when the film insert molded product after cutting is viewed from the front. More preferably, it is 95% or more and 99% or less.

In the present embodiment, as shown in FIG. 2, the heat insulating plate 8 is arranged in a portion corresponding to the flat surface portion 4 (the range of the dotted line in FIG. 3) on the base film provided with the decorative portion 6 by printing or the like. As shown in FIG. 4, the film is shaped after being preheated by heating with a heater device 9 such as an IR heater from both the front and back sides.
The phase difference after shaping in the transparent portion 7 of the insert film 2 is 3 / 13π (phase difference 62.3 nm at a wavelength of 540 nm) or less, preferably 9 / 104π (phase difference 23.4 nm at a wavelength 540 nm), more preferably. Is 1 / 13π (phase difference of 20.8 nm at a wavelength of 540 nm) or less. Within this range, low distortion can be achieved. Incidentally, the phase difference in the non-insulated portion of the insert film 2 exceeds 5 / 26π (phase difference 51.9 nm at a wavelength of 540 nm). Although the phase difference of the heat-insulated decorative portion 6 cannot be measured, it is presumed to be about the same as that of the transparent portion 7.
By suppressing the phase difference of the insert film 2 to this range, the phase difference can be adjusted to an appropriate range when the film insert molded product 1 is formed.

Further, in shaping, by using the heat insulating plate 8 at the time of preheating the film 2, excessive heating can be prevented and the amount of deflection of the shaped product can be suppressed, and the film 2 is set in the mold 14 for injection molding described later. As a result, the transparent portion and the decorative portion of the film insert molded product 1 can be reduced in distortion.
The phase difference between the insert film and the film insert molded product can be obtained by grasping the difference in the amount of transmitted light through the polarizer before and after transmission in the corresponding portion.

Further, the heat-insulated transparent portion 7 of the insert film 2 has an area ratio of 14% or less, more preferably 13% or less, in which the phase difference after shaping exceeds 3 / 13π (phase difference 62.3 nm at a wavelength of 540 nm). It is 12% or less. More preferably, the area ratio after shaping in the transparent portion exceeds 23.4 nm (9 / 104π), more preferably 20.8 nm (1 / 13π).
This area ratio is, for example, divided into 8 places in the horizontal direction and 12 places in the vertical direction in the transparent part, that is, divided into 96 places in total, and the phase difference of each divided part is measured and 3 / 13π (at a wavelength of 540 nm). It can be calculated as the ratio of the area exceeding the phase difference of 62.3 nm).

As shown in FIG. 5, the insert film 2 is appropriately cut into a shape and set in a mold 14 for injection molding, which will be described later. At this time, it is preferable that the insert film 2 is provided with a film gate portion 10 extending toward the gate portion 15 side of the mold 14. The area of the film gate portion 10 is preferably small. By doing so, the shrinkage difference between the front and back surfaces can be reduced when the film insert molded product 1 is formed, and the phase difference between the film insert molded product 1 can be reduced. This is because the film gate portion 10 is easily heated during injection molding, so that residual strain is likely to occur as compared with other portions. It is considered that by reducing the area of the film gate portion 10, the distortion remaining in the entire insert film 2 can be suppressed and the phase difference can be reduced.
Specifically, the area of the film gate portion 10 is preferably 60% or less, particularly 55% or less, and further 35% or less with respect to the front area of the gate portion 15 of the mold 14.

The base resin 3 of the film insert molded product can be formed, for example, by injection molding a thermoplastic resin.
Examples of the thermoplastic resin include polyethylene terephthalate (including a copolymer), polymethylmethacrylate, polystyrene, polycarbonate, and polyamide. Of these, polyethylene terephthalate, polycarbonate, and polyamide are preferable from the viewpoint of high heat resistance, and polycarbonate is more preferable from the viewpoint of high rigidity, high heat resistance, and high impact resistance.

As for the thermoplastic resin of the base resin 3, it is preferable to select a resin having a high glass transition temperature when the film insert molded product is used as the front panel of a liquid crystal display device that requires heat resistance, as in the case of the insert film. That is, the glass transition temperature is 100 ° C. or higher, preferably 120 ° C. or higher, more preferably 130 ° C. or higher, and even more preferably 140 ° C. or higher.
The thermoplastic resin is not particularly limited, but the preferred range of the shear rate during injection molding is 10 (1 / s) or more and 10000 (1 / s) or less, and more preferably 100 (1 / s) or less. s) or more and 1000 (1 / s) or less.
When this thermoplastic resin is used as a front panel of a liquid crystal display device, low strain is strongly required. Therefore, the preferred range of shear rate during injection molding is 300 (1 / s) or less, more preferably 280 (). It is preferably 1 / s) or less, and more preferably 250 (1 / s) or less.
The shear rate of the thermoplastic resin of the base resin 3 can be measured by a simulation utilizing the finite element method after setting the mold structure, the melt flow rate of the resin, the resin temperature, and the mold temperature.

The coefficient of linear expansion of this thermoplastic resin is not limited, but is 30 ppm / K or more and 90 ppm / K or less, preferably 40 ppm / K or more and 80 ppm / K or less, and more preferably 50 ppm / K or more and 70 ppm / K or less. The range. If the linear expansion coefficient is set within the above range, the difference in the linear expansion coefficient between the insert film 2 and the base resin 3 in the film insert molded product 1 can be suppressed, and the difference in shrinkage ratio between the front and back surfaces of the film insert molded product 1 can be suppressed. This is because the distortion of the film insert molded product 1 can be suppressed and reduced.
Therefore, when the coefficient of linear expansion of the thermoplastic resin is 100%, the difference between the coefficient of linear expansion of the thermoplastic resin and the coefficient of linear expansion of the insert film 2 is preferably 40% or less. It is more preferably within 30%, still more preferably within 20%. That is, the coefficient of linear expansion of the thermoplastic resin is preferably a value of 60% to 140% of the coefficient of linear expansion of the insert film 2.
In the present invention, the coefficient of linear expansion can be measured based on, for example, JISK7197.

Thermoplastic resin MFR of the base resin 3 (melt flow rate, 300 ° C., 1.2 kg) ^is, 10 cm 3 / 10min or ^more, 40 cm 3 / 10min or less, preferably 15cm ³ / 10min or ^more, 35 cm 3 / 10min or less, more preferably 20 cm ³ / 10min or ^more, or less 30 cm 3 / 10min. This range is preferable from the viewpoint of moldability.
The flexural modulus of the thermoplastic resin of the base resin 3 is 1 GPa or more, preferably 1.5 GPa or more, and more preferably 2.0 GPa or more. This is from the viewpoint of high rigidity.
The total light transmittance of the thermoplastic resin of the base resin 3 is 70% or more, preferably 75% or more, more preferably 80% or more, still more preferably 85% or more.
These physical property values can be measured based on, for example, JISK7210, JISK7171, JISK7361 and the like.

In the film insert molded product 1, for example, the insert film 2 and the base resin 3 can be integrally formed by injecting and molding the melted thermoplastic resin by arranging the insert film 2 in the cavity of the mold.

In the injection molding step, injection compression molding in which the mold is filled with the thermoplastic resin before closing the mold is preferable. Specifically, when the film insert molded product 1 is injection-molded, as shown in FIG. 6A, the mold 14 including the fixed mold 12 having the resin injection port 11 and the movable mold 13 is molded. The insert film 2 is arranged along at least one cavity surface of the cavity to be formed, and the molten thermoplastic resin is injected into the cavity to first form an injection product and then perform a cutting process or the like to form a film. The insert molded product 1 can be molded.
In the resin injection, after the mold 14 is completely closed (for example, in the state shown in FIG. 6B), the cavity is filled with the resin, and then the mold 14 is closed by compression molding. It is possible to mold the film insert molded product 1 in which distortion is less likely to remain.
It is preferable that the mold 14 is provided with the resin injection port 11 at the bottom so that the resin flows from the bottom to the top from the viewpoint of reducing the strain of the film insert molded product 1.

The molding temperature in the injection molding step is not particularly limited, but it is good for moldability to be equal to or higher than the melting point of the injected resin and lower than the thermal decomposition temperature. Specifically, the resin temperature is 250 to 350 ° C., particularly 280. It is preferably set within the range of ~ 310 ° C. In addition, in order to suppress the distortion of the film insert molded product 1, it is better to set the resin temperature high, and in order to suppress silver caused by the foaming component due to heating, it is better to set the resin temperature low.
The amount of resin compressed in the injection molding die 14 is preferably 1.2 times to 2.5 times. In order to reduce the strain of the film insert molded product 1, the compression amount is preferably in the range of 1.8 to 2.5 times, and in order to suppress appearance defects due to entrainment of air components in the mold 14. The amount of compression is preferably in the range of 1.2 times to 1.8 times.

The gate portion 15 of the mold 14 is not particularly limited, but preferably has a fan-shaped or film-shaped structure so that the resin can flow uniformly. By designing to such a shape, it is possible to reduce the distortion of the film insert molded product 1 after molding.
The fan-shaped fan gate portion has the effect that the molten resin filled from the nozzle spreads in the product width direction to keep the speed constant while reducing the speed. The film-shaped film gate portion can reduce warpage and deformation by allowing the molten resin spread over the width of the product to flow at a constant speed within the range of the gate width.

The injection product taken out from the mold 14 is preferably annealed in order to relieve the residual stress. Annealing is preferably carried out in a temperature region near the glass transition point, for example, by heat treatment at 100 ° C. to 130 ° C. for 1 hour to 3 hours, and more specifically, heat treatment at about 105 ° C. × about 2 hours. Can be done.
The mechanism by which the film insert molded product 1 is distorted is that during injection molding, the resin in a fluid state is filled in the mold 14 and then cooled by coming into contact with the mold 14, and the resin near the mold 14 is cooled before shrinkage. While solidification (residual stress of compression), the resin near the center of the mold 14 is delayed in solidification and then tries to shrink, but it cannot shrink because the resin near the surface layer is solidified (residual tension). stress). It is considered that strain is generated by these residual stresses. Therefore, by annealing again in the temperature region near the glass transition point of the resin, the residual stress due to the cooling and solidification of the resin is released, and the film insert molded product 1 has low strain. It becomes.

For the injection product, it is preferable to cut the overhanging portion formed on the gate portion 15 side after annealing. By cutting the overhanging portion, the residual stress due to the cooling and solidification of the resin generated by the above mechanism is released at the cut portion, and the film insert molded product 1 is reduced in strain.
The cutting process may be performed before annealing.

In the film insert molded product 1 of the present invention, the average value of the phase difference in the transparent portion 7 is 19 / 104π (phase difference 49.3 nm at a wavelength of 540 nm) or less, preferably 17 / 104π (phase difference 44.1 nm at a wavelength of 540 nm). Hereinafter, it is more preferably 15 / 104π (phase difference of 38.9 nm at a wavelength of 540 nm) or less.
Further, in the film insert molded product 1 of the present invention, the area ratio in the transparent portion where the phase difference exceeds 62.3 nm (3 / 13π) is preferably 40% or less, more preferably 35% or less. This area ratio can be calculated by the same method as for the insert film.
The film insert molded product 1 is used as a resin molded product in all fields, but is particularly preferably used in applications that have a three-dimensional shape and require high-quality aesthetics and accurate pattern reproducibility. Above all, it is suitable as a front panel of a liquid crystal display device mounted on an ATM of a financial institution, a touch panel screen used in an automatic ticket vending machine such as a railway station / restaurant, a household electric appliance, a mobile phone, an audio device, an in-vehicle device, and other electronic products. Used for.
The film insert molded product 1 can be used as a front panel instead of the conventional resin substrate or glass substrate, and can be used as a front panel by forming an adhesive layer on the back surface and attaching a sensor (electrode). .. According to this, it is possible to create a front panel having a three-dimensional shape having excellent pattern reproducibility and excellent visibility.

Hereinafter, one embodiment of the present invention will be limited. However, the present invention is not limited to this embodiment.

In order to produce an insert film molded product having a form as shown in FIG. 1, the following film was produced.

<Creation of insert film>
(Film 1)
A film obtained by forming a film of polycarbonate with a T-die was used, and the film was coated with a coating agent having AR, AF, and HC functions by a roll coating method. This was cut into sheets and then printed by screen printing to obtain a base film.
Next, this base film was preheated from above and below with an IR heater. The preheating temperature was 210 ° C. Then, the preheated film was set in a shaping mold, and shaping was performed by compressed air under the conditions of 280 ° C. and 8 MPa. The phase difference of the transparent portion of the obtained insert film was measured, and the average value was calculated to be 9 / 26π (phase difference of 93.5 nm at a wavelength of 540 nm). Further, in the transparent portion of the obtained insert film, the ratio of the area having a phase difference of more than 62.3 nm (3 / 13π) was 65%.

(Film 2)
Using the base film used in the above film 1, the temperature of the character part and the transparent part was adjusted to 100 to 120 ° C., and the temperature of the other parts was adjusted to 200 ° C. to 220 ° C. in the preheating step. An insert film was prepared in the same procedure as the above film 1.
Specifically, the preheating area was divided into 6 × 6 blocks, and the set temperature of the IR heater was changed for each block to preheat, and the temperature of each part was set as described above. The phase difference of the transparent portion of the obtained insert film was measured, and the average value was calculated to be 9 / 52π (phase difference of 46.7 nm at a wavelength of 540 nm). Further, the proportion of the area having a phase difference of more than 62.3 nm (3 / 13π) in the transparent portion was 32%.

(Film 3)
Using the base film used in the above film 1, in the preheating process, ^{a heat insulating plate having a size (252 cm 2} ; width 12 cm × length 21 cm) occupying 70% of the front projected area of the film insert molded product part (Fig.) An insert film was prepared in the same procedure as the above film 2 except that the two-dot chain line 8a) of 7 was installed in the center of the product section.
As a heat insulating plate, a fiber composite material "HICAL" made of silicic acid compound binder and glass fiber (thickness 5 mm, linear expansion coefficient 7.3 x ^10-5 / ° C, thermal conductivity 0.08 W / m) -K) was used. As shown in FIG. 4, the heat insulating plate was arranged so as not to come into contact with the decorative portion and the transparent portion of the base film so as to preheat the heat insulating plate so that the heat of the IR heater was blocked at the portion. When the phase difference in the transparent portion of the obtained insert film was measured and the average value was calculated, it was 26.0 nm (5 / 52π). Further, the proportion of the area having a phase difference of more than 62.3 nm (3 / 13π) in the transparent portion was 15%.

(Film 4)
The size of the heat insulating plate used in the preheating process is 79% of the front projected area of the film insert molded product part (the size covering the entire decorative part (286 cm ² ; width 13 cm x length 22 cm), and the transparent part. The above film 3 is arranged so as to cover an area extending outward by about 1 cm or more around the entire circumference of the character portion (one-dot chain line 8b in FIG. 7) so that the area including the decorative portion is insulated. An insert film was prepared in the same procedure as in the above. When the phase difference of the window portion of the obtained insert film was measured and the average value was calculated, it was 1 / 13π (phase difference of 20.8 nm at a wavelength of 540 nm). The proportion of the area having a phase difference of more than 62.3 nm (3 / 13π) in the transparent portion was 12%.

(Film 5)
An insert film was prepared in the same procedure as the above film 4 except that a film without decoration was used. When the phase difference of the obtained insert film was measured and the average value was calculated, it was 5 / 26π (phase difference of 51.9 nm at a wavelength of 540 nm), and when the phase difference at the standing wall portion was measured and the average value was calculated. It was 9 / 26π (phase difference 93.5 nm at a wavelength of 540 nm). In addition, the proportion of the area exceeding the phase difference of 3 / 13π (phase difference of 62.3 nm at a wavelength of 540 nm) was 18% of the entire heat insulating portion.

(Measurement)
The phase difference between the films 1 to 5 was measured as follows. In addition, the presence or absence of deflection at the time of shaping the insert film was determined as follows. These results are shown in Table 1 below.

<Phase difference>
The phase difference of the insert film was measured by a two-dimensional birefringence evaluation system PA-110 manufactured by Photonic Lattice Co., Ltd. More specifically, the phase difference in the plane direction was found by grasping the difference in the amount of transmitted light when the incident light before transmission and the transmitted light after transmission were passed through the polarizer in the corresponding portion. As for the area ratio, as described above, the phase difference of each divided portion divided into 96 sections was measured, and the ratio of the area exceeding the phase difference of 3 / 13π (phase difference of 62.3 nm at a wavelength of 540 nm) was calculated. ..

<Deflection>
At the time of shaping, the shape of the insert film was visually observed, and it was determined that the shape of the cavity that did not closely follow the shape of the shaping cavity was deflected.

<Film insert molded product>
The film 3 or 4 was placed on the cavity surface of the mold, and the molten thermoplastic resin was injected to prepare film insert molded products of Examples 1 to 5 and Comparative Examples 1 to 3.
The resin composition constituting the injected resin, a polycarbonate resin (shear rate 250 [1 / s] or less, the glass transition temperature of 140 ° C. or higher and a melt flow rate (300 ° C., 1.2 kg) is 20cm ³ / 10min~ 30 cm ³ / 10min, flexural modulus 2GPa or more, 85% or more total light transmittance) was used.
As shown in FIG. 5, the mold used had a resin injection port provided at the bottom.

<Annealed>
Annealing was performed to prepare a film insert molded product. The annealing conditions were 105 ° C. × 2 hours.

<Cutting>
In the cutting process, the overhanging portion formed on the gate portion side of the mold was cut off by the resin composition.

(Example 1)
Using the film 4, the thermoplastic resin was injected at a resin temperature of 300 ° C. and a compression amount of 1.83 times, and film insert molding was performed. Next, after annealing under the above conditions, the overhanging portion was cut to produce a film insert molded product. When the phase difference of this window portion was measured, it was 2 / 13π (phase difference of 41.5 nm at a wavelength of 540 nm).

(Example 2)
A film insert molded product was obtained in the same procedure as in Example 1 except that the overhanging portion was cut after the film insert molding and then annealed. When the phase difference of this window portion was measured, it was 2 / 13π (phase difference of 41.5 nm at a wavelength of 540 nm).

(Example 3)
A film insert molded product was obtained in the same procedure as in Example 1 except that the film insert molding was performed at a resin temperature of 320 ° C. When the phase difference of this window portion was measured, it was 15 / 104π (phase difference of 38.9 nm at a wavelength of 540 nm).

(Example 4)
A film insert molded product was obtained in the same procedure as in Example 1 except that the mold was turned upside down during film insert molding and the resin injection port was turned upward. When the phase difference of this window portion was measured, it was 9 / 52π (phase difference of 46.7 nm at a wavelength of 540 nm).

(Example 5)
A film insert molded product was obtained in the same procedure as in Example 1 except that the amount of compression during film insert molding was doubled. When the phase difference of this window portion was measured, it was 7 / 52π (phase difference of 36.3 nm at a wavelength of 540 nm).

(Comparative Example 1)
A film insert molded product was obtained in the same procedure as in Example 1 except that the film insert was molded using the film 3. When the phase difference of this window portion was measured, it was 3 / 13π (phase difference of 62.3 nm at a wavelength of 540 nm) or less.

(Comparative Example 2)
After the film insert molding using the film 4, an annealing step of 105 ° C. × 2 hours was performed, and an insert molded product was obtained in the same procedure as in Example 1 except that no cutting process was performed. When the phase difference of this window portion was measured, the phase difference was 5 / 26π (phase difference of 51.9 nm at a wavelength of 540 nm).

(Comparative Example 3)
An insert-molded product was obtained in the same procedure as in Example 1 except that the film 4 was inserted-molded, then the overhanging portion was cut, and the annealing step was not performed. When the phase difference of this window portion was measured, the phase difference was 5 / 26π (phase difference of 51.9 nm at a wavelength of 540 nm).

(test)
The following tests were carried out using the film insert molded products of Examples 1 to 5 and Comparative Examples 1 to 3. The phase difference was measured in the same manner as described above. These results are shown in Table 2 below.

<Appearance>
The appearance was evaluated by shining a backlight from the rear of the window of the film insert molded product, passing a polarizing plate from the front side, visually confirming the presence or absence of rainbow unevenness and silver, and evaluating with the following indexes.
◎: Both rainbow unevenness and silver do not occur, and visibility is excellent. ○: Silver is seen a little, but there is no rainbow unevenness, and visibility is excellent. ×: Rainbow unevenness occurs, and visibility is poor.

<Film setability>
The film settability was evaluated by the following indexes when fixing the shaped product to the mold in film insert molding.
◯: There is no deflection in the shaped product and there is no problem when fixing it to the mold. ×: The shaped product has enough deflection to interfere with fixing to the mold.

(Test results)
As shown in Table 2, Examples 1 to 5 in which the phase difference in the window portion of the film insert molded product is within a specific range are three-dimensionally molded films using the decorated and shaped insert film. Although it was an insert-molded product, it had no distortion or uneven rainbow, and had excellent visibility. Further, in Examples 1 to 5, since excessive heating is prevented by using a heat insulating plate at the time of preheating the film in the shaping step and the amount of deflection of the shaped product is suppressed, the film setting property is excellent. It has been shown.
On the other hand, Comparative Examples 1-3 had a high phase difference in the window portion, were inferior in visibility, and were not suitable for printing. In Comparative Example 1 in which the phase difference was particularly high, the amount of deflection was large from the viewpoint of film settability, which hindered molding.

As described above, from the effects of the above-described Examples and Comparative Examples, the value of the phase difference of the film insert molded product defined in the present invention becomes a critical point, and a large difference appears in the appearance and the settability of the film. Demonstrated.

1 Film insert molded product 2 Insert film 3 Base resin 4 Flat part 5 Standing wall part 6 Decorative part 7 Transparent part 8 Insulation plate 9 Heater device 10 Film gate part 11 Resin injection port 12 Solid type 13 Movable type 14 Mold 15 Gate

Claims (8)

The insert film on the front surface side is composed of two layers with a base resin formed by injection molding on the back surface side, and has a shape having a flat surface portion and a standing wall portion whose periphery is raised on the back surface side, and a transparent portion is formed on the flat surface portion. It is a film insert molded product in which the transparent portion is provided with a decorative portion around the transparent portion, and the phase difference of the transparent portion is 19 / 104π (phase difference of 49.3 nm at a wavelength of 540 nm) or less. Film insert molded product. 22 parts of the film insert molded product according to claim 1 (78 parts of acrylic resin having a glutarimide structure in the main chain, styrene-acrylonitrile copolymer (composition: 73% by mass of styrene and 27% by mass of acrylonitrile, weight average molecular weight 220,000). , 0.05 part of antioxidant and 0.05 part of phenolic antioxidant are kneaded with a twin-screw extruder and extruded to obtain pellets, and the obtained pellets are melt-extruded from a T-die at a temperature of 280 ° C. An insert film is a resin film having a thickness of 100 μm, which is obtained by sequentially biaxially stretching an unstretched film obtained by discharging it onto a cooling roll at 110 ° C. so that the stretching ratio is 2.0 times in both vertical and horizontal directions. (Excluding film insert molded products used as). The film insert molded product according to claim 1 or 2, wherein the insert film is formed by using a resin film made of a resin composition containing polyethylene terephthalate or polycarbonate. The film insert molded product according to any one of claims 1 to 3, wherein the insert film has a transparent portion having a phase difference of 3 / 13π (phase difference of 62.3 nm at a wavelength of 540 nm) or less after shaping. The present invention according to any one of claims 1 to 4, wherein the insert film has a transparent portion having an area ratio of 14% or less in which the phase difference exceeds 3 / 13π (phase difference 62.3 nm at a wavelength of 540 nm) after shaping. Film insert molded product. The film insert molded product according to any one of claims 1 to 5, wherein the thermoplastic resin has a coefficient of linear expansion of 30 ppm / K or more and 90 ppm / K or less. The film insert molded product according to any one of claims 1 to 6, wherein the thermoplastic resin has a shear rate of 300 (1 / s) or less during injection molding. A front panel of a liquid crystal display device using the film insert molded product according to any one of claims 1 to 7.

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