TW201433435A - Casting die, production method of die head, and production method of film - Google Patents

Abstract

There are provided a casting die, a production method of die head, and a production method of film, so as to prevent occurrence of crack at the time of forming a DLC film on a base of a die head. A die head is detachably attached to a dope discharge port of a casting die. The die head includes a base, a foundation layer, and a DLC film. The base is made of stainless steel, and the foundation layer is made of tungsten carbide (WC). The DLC film is formed on the foundation layer. A combination of a linear expansion coefficient between the base and the foundation layer, a length of the die head in a longitudinal direction thereof, and a heating temperature in vapor-phase film deposition is determined, such that stress applied to the foundation layer, which is calculated with reference to external force caused by distortion due to thermal expansion of the base and the foundation layer, is less than breaking stress of the foundation layer, during formation of the DLC film. The foundation layer and the DLC layer are formed based on this combination.

Description

Cast film, die and film manufacturing method

The present invention relates to a casting die, a method of manufacturing the die, and a method of producing a film.

A translucent polymer film (hereinafter referred to as a film) is light in weight and easy to mold, and thus is widely used as an optical film. Among them, a cellulose ester-based film such as a cellulose halide is used as an optical film (a polarizing plate protective film or a retardation film) of a liquid crystal display device in addition to a film for photo-sensing.

As a well-known method, a main method for producing a film is a solution film forming method. In the solution film forming method, a casting film forming process, a casting film drying process, a stripping process, and a wet film drying process are sequentially performed. In the cast film forming process, a polymer solution containing a polymer and a solvent (hereinafter referred to as a dope) is discharged by a casting die, and a cast film is formed on the moving support. In the cast film drying process, the solvent is evaporated from the cast film or the cast film is cooled until the cast film can be independently transferred. In the stripping process, the cast film of the cast film drying process is peeled off from the support as a wet film. In the wet film drying process, the solvent is evaporated from the wet film to serve as a film.

The casting die has a pair of die lips arranged side by side in the moving direction of the support body, a pair of side plates covering both end portions of the pair of die lips, and surrounded by a pair of die lips and a pair of side plates The road to the formation. A slit-shaped flow path is formed in a cross section orthogonal to the flow direction of the dope. The slit is formed into an elongated rectangle composed of a short side extending in the moving direction of the support and a long side extending in a direction (width direction) orthogonal to the moving direction of the support. The lip plate and the side plate have a small coefficient of thermal expansion and are formed of stainless steel having a lower solubility with respect to the solvent used in the dope. The stainless steel is, for example, SUS316L or the like.

The casting die causes the dope to flow from the outlet of the flow path to the moving support. As a result, a liquid bead is formed between the front end portion of the lip plate and the support. In the cast film forming process, if the bead becomes unstable, uneven thickness may occur in the cast film. Therefore, stabilization of the bead is achieved by strengthening the front end portion of the lip plate on which the liquid bead is first formed.

However, the Vickers hardness of SUS316L is about Hv180 and is relatively soft, so it is difficult to strengthen the front end portion by machining. Therefore, the front end portion of the lip plate is reinforced by providing a hard layer harder than SUS316L at the front end portion of the die plate and performing predetermined machining on the hard layer. As the hard layer, a tungsten carbide (WC) layer as disclosed in, for example, Japanese Patent Laid-Open Publication No. 2003-200097 is known.

Also, the preferred shape of the front end portion of the die plate changes depending on the manufacturing conditions of the film. Therefore, the lip plate is divided into a lip body which is a flow path inlet and a front end portion (hereinafter referred to as a die) which serves as a flow path outlet, and the die is detachably attached to the die plate main body. By selecting such a die, it is easy to switch and manufacture a plurality of films on one manufacturing line.

However, if the film formation process is continuously performed for a long period of time, the tungsten carbide layer provided on the die is corroded. The corrosion of the tungsten carbide layer is caused by the dissolution of the binder metal (cobalt atoms, etc.). If the casting die in which the tungsten carbide layer is already in a corrosive state is directly used, the tungsten carbide layer will be peeled off, and the occurrence of the occurrence of streaks on the surface of the film due to the peeling will occur. So have to be in The casting film forming process is terminated every time the casting film forming process is performed to replace the new die, resulting in a decrease in film production efficiency.

Based on this background, as disclosed in Japanese Patent Laid-Open Publication No. 2012-148442, a diamond-like carbon (DLC) film having a longer and stable life than a tungsten carbide layer is formed on a die. Further, with the increase in size of liquid crystal display devices, the demand for wide-format optical films has increased dramatically. In order to make a wide-format optical film, it is necessary to set the interval between the pair of side plates larger than before, and to lengthen the main body of the lip plate and the die. If the die is lengthened, the amount of warpage of the die which is generated when the DLC film is formed will increase. It is difficult to mount the warped die on the main body of the die. Therefore, in Japanese Laid-Open Patent Publication No. 2012-148442, the warpage of the die is suppressed to a certain range by forming a DLC film at a heating temperature of 130 ° C or more and 200 ° C or less.

However, in the case where a die having a DLC film on the surface and the warpage is suppressed is attached to the dope outlet of the casting die to form a solution, although the film does not occur on the surface of the film at the beginning of film formation. The failure, but once the film is continuously formed for a long time, a streaky failure occurs, and measures need to be taken. The occurrence rate of such a streak failure becomes high when a cast film having a long strip shape corresponding to the widening of the film is used.

Accordingly, it is an object of the present invention to provide a casting die, a die and a method of producing a film corresponding to the widening of a film.

When the occurrence of the above-described streaky failure was investigated, it was found that fine cracks occurred in the DLC film or the underlying layer, and streaky failure occurred due to cracking or peeling of the DLC film caused by the crack. Based on this finding, intensive studies have been conducted, and it has been found that the fine crack is caused by the thermal expansion strain generated between the base layer and the substrate at the time of film formation of the DLC film.

The casting die of the present invention for discharging the dope to the support has a separable die at the dope outlet, wherein the die has a base, a base layer, a DLC film, and respective linear expansion coefficients of the base and the base layer having a σ1 smaller than σ2 The combination of the length in the longitudinal direction of the die and the heating temperature at the time of forming the DLC film, the dope contains a polymer and a solvent. The base is made of stainless steel. The base layer is disposed on the substrate and formed of a hard material. The DLC film is formed on the underlayer by a vapor phase film formation method. Here, σ1 is a stress acting on the underlayer by a thermal expansion strain of the underlayer and the underlayer caused by a temperature rise when the DLC film is formed, and σ2 is a fracture stress of the underlayer.

The compressive force acting on the substrate is PB, the traction force acting on the base layer is PL, and the cross-sectional area of the base layer in the cross section orthogonal to the longitudinal direction of the die is set to AL, according to σ1=(PB- PL)/AL is preferable to determine the stress σ1 acting on the underlayer.

When the length in the long side direction is LY and the maximum length in the cross section orthogonal to the long side direction is LW, LY 50. LW has a length LY of 1500 mm or more, a thickness of the underlayer of 70 μm or more and 130 μm or less, and a thickness of the DLC film of 0.7 μm or more and 2 μm or less.

The substrate is formed of any one of SUS316L, SUS329J1, and SUS630, and the base layer is preferably formed of tungsten carbide.

The difference in hardness between the base layer and the DLC film is preferably within 500 Hv.

The hardness of the DLC film is preferably 1300 Hv or more.

The vapor phase film formation method is preferably any one of ion evaporation, ion plating, and plasma chemical vapor deposition (CVD).

The method for producing a film of the present invention comprises a cast film forming step, a cast film drying step, a stripping step, and a wet film drying step. The cast film forming step forms a film composed of a dope by flowing a dope from a casting die to a support. The dope contains the polymer and solvent. Casting die There is a detachable die at the dope outlet. The die has a substrate, a substrate layer, and a DLC film. The base is made of stainless steel. The substrate layer is disposed on the substrate. The base layer is formed of a hard material. The DLC film is disposed on the substrate layer by a vapor phase film formation method. The die has a combination of each of the linear expansion coefficients of the base and the base layer having a σ1 smaller than σ2, the length in the longitudinal direction of the die, and the heating temperature at the time of forming the DLC film. In the casting film drying step, the solvent is evaporated from the casting film until the casting film can be independently transferred. In the stripping step, the cast film is peeled off from the support to form a wet film. In the wet film drying step, the solvent is evaporated from the wet film to serve as a film. Here, σ1 is a stress acting on the underlayer by a thermal expansion strain of the underlayer and the underlayer caused by a temperature rise when the DLC film is formed, and σ2 is a fracture stress of the underlayer.

The method for producing a die according to the present invention includes a base layer forming step (step A), a DLC film forming step (step B), and a determining process for the crack arresting suitable condition (step C), and the die is attached to the flow for causing the dope to flow out. An elongated column of a die-shaped dope outlet, the dope comprising a polymer and a solvent. In step A, a base layer is formed on a stainless steel substrate. The base layer is formed of a hard material. In the step B, a DLC film is formed on the underlayer by a vapor phase film formation method. In the step C, a combination of the linear expansion coefficients of the substrate and the underlayer, the length of the longitudinal direction of the die, and the heating temperature in the vapor phase film formation method are determined before the step A. In step C, the aforementioned combination is determined to be σ1 smaller than σ2. Where σ1 is the stress acting on the base layer by the thermal expansion strain of the base and the base layer in the step B, and σ2 is the fracture stress of the base layer.

According to the invention, when the DLC film is formed on the underlayer, the generation of cracks in the underlayer or the DLC film is suppressed, and a die composed of a crack-free DLC film can be obtained. By using a casting die having such a die, the peeling phenomenon of the DLC film caused by the crack disappears. Moreover, the low friction characteristic of the DLC film due to peeling is partially lowered, so in the falling portion At the exit of the die, the solid matter is generated and grown, but as the peeling disappears, the generation/growth of the solid matter is suppressed. Therefore, the number of times the nozzle can be cleaned by stopping the casting to remove the dope solid matter can be greatly reduced, so that the product loss due to the suspension casting can be reduced, and the film can be continuously and stably produced. These effects can also be obtained in the widening of the film.

10‧‧‧solution film making equipment

12‧‧‧Casting room

13‧‧‧ Needle plate tenter

15‧‧‧Drying room

16‧‧‧Cooling room

17‧‧‧The take-up room

21‧‧‧casting mode

22‧‧‧casting roller

22a‧‧‧Drive shaft

22b‧‧‧Roller body

22c‧‧‧Sun

23‧‧‧Decompression chamber

24‧‧‧ stripping roller

28‧‧‧Liquor

29‧‧‧Flow

29a‧‧‧Inlet flow path

29b‧‧‧Management

29c‧‧‧Slit flow path

29i‧‧‧ entrance

29o‧‧ Export

32‧‧‧temperature control device

33‧‧‧Liquid beads

34‧‧‧cast film

35‧‧‧ Wet film

40‧‧‧Transfer Department

41‧‧‧Support roller

45‧‧‧film

47, 56‧‧‧ side section cutting machine

49‧‧‧roll

52‧‧‧Adsorption recovery unit

54‧‧‧Electrical rod

55‧‧‧Knurling roller

61‧‧‧pressure roller

62‧‧‧Volume core

63‧‧‧Winding machine

71‧‧‧ side panels

71a, 72a‧‧‧Flow path forming surface

72‧‧‧Mold lip

72b‧‧‧ both ends

81‧‧‧Mold lip body

82‧‧‧die

85‧‧‧Base

85a‧‧‧lower front end

85b‧‧‧ upper end

86‧‧‧DLC film

92‧‧‧ basal layer

92a‧‧‧ Flowing pavement

92b‧‧‧Exposure

95‧‧‧Installation holes

96, 115‧‧‧ screw holes

97‧‧‧Installation bolts

99‧‧‧film forming device

100‧‧‧Processing room

101‧‧‧ reflector

120‧‧‧filament

103‧‧‧Anode

104‧‧‧target electrode

105‧‧‧ air duct

106‧‧‧Fixed parts

107‧‧‧ Plasma source

108‧‧‧Reactive gas

109‧‧‧Power Supply Department

109a‧‧‧ reflector power supply

109b‧‧‧ filament power supply

109c‧‧‧Anode power supply

109d‧‧‧ Target power supply

110‧‧‧ fixed board

111‧‧‧foot board

112‧‧‧ fixing bolts

121‧‧‧Determining process

122‧‧‧ basal layer formation process

123‧‧‧DLC film formation process

d‧‧‧DLC film thickness

LX, LY, LZ, LW‧‧‧ length

X, Y, Z‧‧ Direction

The above objects and advantages will be readily understood by those skilled in the art from a <RTIgt;

Fig. 1 is a side view showing an outline of an example of a solution film forming apparatus.

Fig. 2 is a perspective view showing an outline of an example of a casting die, a casting drum, and the like in the casting chamber.

Fig. 3 is a partial cross-sectional view showing an outline of an example of a tip end portion of a casting die.

Fig. 4 is a perspective view showing an outline of an example of a casting die.

Fig. 5 is an exploded perspective view of the casting die.

Fig. 6 is a perspective view showing an outline of an example of a flow path provided in a casting die.

Fig. 7 is a cross-sectional view showing an example of an outline of a flow path.

Fig. 8 is a perspective view showing an outline of an example of a lip having a lip body and a die.

Figure 9 is an exploded perspective view of the die lip.

Fig. 10 is a cross-sectional view showing an example of a schematic view of a die.

Figure 11 is a cross-sectional view showing the outline of the front end portion of the lip plate constituting the outlet.

Fig. 12 is a cross-sectional view showing an example of a schematic view of a base and a base layer.

Fig. 13 is a schematic cross-sectional view showing an example of a DLC film forming apparatus.

Fig. 14 is a perspective view showing an example of an outline of a die attached to a fixture.

Fig. 15 is an exploded perspective view of the fixing member and the die.

Figure 16 is a flow chart showing a method of manufacturing a die.

(solution film making equipment)

In the first drawing showing an example of the solution film forming apparatus, the solution film forming apparatus 10 has a casting chamber 12, a pin tenter 13, a drying chamber 15, a cooling chamber 16, and a winding chamber 17. The casting chamber 12 is provided with a casting die 21, a casting drum 22, a decompression chamber 23, and a stripping roller 24.

As shown in Fig. 2, the casting drum 22 includes a drive shaft 22a disposed horizontally and a drum main body 22b fixed to the drive shaft 22a. The drive shaft 22a is connected to a drive unit (not shown). The casting drum 22 is preferably made of stainless steel, and is preferably made of SUS316L from the viewpoint of sufficient corrosion resistance and strength.

As shown in Fig. 3, the casting die 21 has a flow path 29 inside. The lower end portion of the casting die 21 has an outlet 29o of the flow path 29 opening. The casting die 21 is disposed such that the outlet 29o is close to the circumferential surface 22c of the casting drum 22. Details of the casting die 21 will be described later. By the rotation of the casting drum 22, the circumferential surface 22c moves in the X direction at a predetermined speed in the vicinity of the outlet 29o. Further, the X direction indicates the rotation direction of the casting drum 22, the Y direction indicates the direction orthogonal to the X direction (the width direction of the casting film 34), and the Z direction indicates the direction orthogonal to the XY plane including the X direction and the Y direction. (the height direction of the casting die 21).

The dope 28 is sent to the flow path 29 of the casting die 21. Regarding the dope 28, the dope 28 flows out from the outlet 29o toward the peripheral surface 22c. The liquid bead 33 is formed by the concentrated liquid 28 which reaches the peripheral surface 22c from the outlet 29o. The dope 28 reaching the circumferential surface 22c extends in the X direction on the circumferential surface 22c, and as a result, the strip-shaped cast film 34 is formed. Thereby, formation is performed by the casting die 21 and the casting drum 22 The cast film forming process of the casting film 34.

The decompression chamber 23 is disposed on the upstream side in the X direction from the casting die 21 . The decompression chamber 23 sucks the gas on the upstream side in the X direction of the liquid droplet 33 by the control of a controller (not shown). When the gas is sucked, the pressure on the upstream side of the liquid droplet 33 is lower than the pressure on the downstream side of the liquid droplet 33. By the decompression chamber 23, it is possible to attract the wind that is generated in accordance with the movement of the circumferential surface 22c and flows in the X direction in the vicinity of the circumferential surface 22c. Therefore, the vibration of the liquid bead 33 caused by the impact with the wind is suppressed. Further, the length of the liquid bead 33 is shortened due to the suction, and the vibration of the liquid bead 33 is suppressed to a degree corresponding to the amount of shortening.

A temperature control device 32 is connected to the casting drum 22. The temperature adjustment unit 32 has a temperature adjustment unit that adjusts the temperature of the heat medium. The temperature control device 32 circulates the heat medium adjusted to a desired temperature between the temperature adjustment unit and the flow path provided in the casting drum 22. By the circulation of the heat medium, the temperature of the circumferential surface 22c of the casting drum 22 can be maintained at a desired temperature. Further, the solution film forming apparatus 10 is provided with a condensing device that condenses the solvent contained in the atmosphere in the casting chamber 12, and a recovery device that recovers the condensed solvent, and is contained in the atmosphere in the casting chamber 12. The concentration of the solvent is kept within a certain range. Thereby, a casting film drying process for evaporating the solvent from the casting film 34 is performed in the casting drum 22.

The peeling roller 24 is disposed on the downstream side in the X direction from the casting die 21. The stripping roller 24 strips the casting film 34 formed on the circumferential surface 22c as a stripping process of the wet film 35. The wet film 35 is guided to the downstream side of the casting chamber 12.

As shown in Fig. 1, a pin tenter 13, a drying chamber 15, a cooling chamber 16, and a winding chamber 17 are disposed in this order downstream of the casting chamber 12. The transfer chamber 40 is provided between the casting chamber 12 and the pin tenter 13. A plurality of support rollers 41 are arranged in the transfer unit 40. Support roller 41 by unillustrated The motor is shown rotating. The support roller 41 supports the wet film 35 and is guided to the pin tenter 13. In addition, the number of the support rollers 41 of the transfer unit 40 is not limited to two, and may be one or more. Also, the support roller 41 may be a free roller.

The pin tenter 13 has a pair of looped chains, a pulley, and a dry air feeder. The endless chain has a plurality of pins mounted at a certain spacing. The plurality of pins are held so as to penetrate both ends in the width direction of the wet film 35. The endless chain circulates around the way around the pulley. The dry air feeder supplies dry air to the wet film 35 held by the pin. A brush is provided at the entrance of the pin tenter 13. The brush presses both side portions of the wet film 35 and allows the pin to penetrate the wet film 35. The wet film 35 held by the pins on both sides is conveyed by the cyclic traveling of the endless chain. During the transfer, the solvent is evaporated from the wet film 35 by contact with the dry air, and becomes the film 45. Thus, the self-transferring portion 40 to the pin tenter 13 performs a wet film drying process for evaporating the solvent from the wet film 35 to form the film 45.

A side portion cutter 47 is disposed between the pin tenter 13 and the drying chamber 15. The side portion cutter 47 cuts off both side portions of the film in which the through holes remain due to the pins from the center portion. The cut both sides are sent to a crusher (none of which is shown) through a cutting fan, and are shredded, and are recycled as a raw material such as a dope.

The drying chamber 15 has a plurality of rollers 49. The film 45 is wound on the roller 49 to be conveyed. The temperature, humidity, and the like of the atmosphere in the drying chamber 15 are adjusted by an air conditioner (not shown). The drying process of the film 45 is performed in the drying chamber 15. An adsorption recovery device 52 is connected to the drying chamber 15. The adsorption recovery device 52 adsorbs the solvent evaporated from the film 45 for recovery.

The cooling chamber 16 cools the film 45 to a temperature at which the film 45 is substantially equivalent to room temperature. Between the cooling chamber 16 and the winding chamber 17, a static elimination bar 54 and knurling are disposed in this order from the upstream side. The roller 55 and the side portion cutter 56 are given. The static removing bar 54 performs a static elimination process for removing electricity from the charged film 45. The knurling applying roller 55 applies a knurling for winding to both side portions of the film 45. The side portion cutter 56 cuts both side portions of the film 45 in such a manner that the knurl remains on the product film side.

The take-up chamber 17 has a coiler 63. The winder 63 winds the film 45 around the winding core 62 to take up a roll shape. The pressure roller 61 presses the film 45 against the winding core 62 side.

As shown in Fig. 4, the casting die 21 has a pair of side plates 71 made of stainless steel (SUS316 or SUS316L, etc.) and a pair of die lips 72. The pair of die lips 72 are opposed to each other. As shown in Fig. 5, a flow path forming surface 72a is formed on the adhesion surface of the die lip 72, and the flow path 29 is formed by the flow path forming surface 72a as shown in Fig. 6. The pair of side plates 71 are covered by the mold. The both end faces 72b of the lip 72 are attached. Both ends of the flow path 29 are closed by the side plate 71.

As shown in Fig. 6, the flow path 29 has an inlet flow path 29a, a manifold 29b, and a slit flow path 29c, which are sequentially connected from the inlet 29i at the upper portion of the casting die 21 to the outlet (dope flow outlet) 29o. Settings. The inlet flow path 29a conveys the concentrated liquid 28 flowing from the inlet 29i to the manifold 29b. The manifold 29b expands the dope 28 in the Y direction, and moderates the strain of the polymer molecules contained in the dope 28, and then sends the dope 28 to the slit flow path 29c. The slit flow path 29c sends the dope 28 to the outlet 29o.

As shown in Fig. 7, the slit flow path 29c is formed in an elongated rectangular shape in a cross section on the XY plane orthogonal to the flow direction (Z direction) of the concentrated liquid 28 in the flow path 29. In the cross section of the slit flow path 29c, one pair of long sides is constituted by the flow path forming surface 72a, and the short side is constituted by the flow path forming surface 71a.

As shown in Figs. 8 and 9, the die plate 72 is divided into a die plate body 81 made of stainless steel (SUS316 or SUS316L, etc.) and a die 82. The die 82 is flat along the XZ The cross section of the surface is a substantially wedge-shaped prism which is elongated in the Y direction, and is detachably attached to the lip main body 81 by a mounting bolt 97. Thereby, the die 82 is disposed to be separable at the outlet 29o of the casting die 21. The division position of the die plate main body 81 and the die 82 is located in the middle of the slit flow path 29c in the flow path forming surface 72a.

(die)

As shown in FIG. 10, the die 82 has a base 85, a base layer 92, and a DLC film 86. As shown in Fig. 9, the base 85 is made of stainless steel (SUS316 or SUS316L, etc.), and is formed of a prismatic body having a substantially wedge-shaped cross section along the XZ plane. The base 85 has, for example, four mounting holes 95 at a certain interval in the Y direction. As shown in Fig. 11, a screw hole 96 is formed in the die plate main body 81 at a position corresponding to the mounting hole 95. The mounting bolt 97 is attached to the screw hole 96 via the mounting hole 95, whereby the die 82 is detachably fastened to the die main body 81.

As shown in Fig. 12, the base layer 92 is formed on the surface of the lower front end portion 85a of the base 85. The surface of the base layer 92 is sharply formed in the Z direction, and has a flow path surface 92a for forming the flow path 29 and an exposed surface 92b exposed to the outside.

The material for forming the underlayer 92 may be a hard material such as tungsten carbide (WC), Al ₂ O ₃ , TiN or Cr ₂ O ₃ , and WC is particularly preferable. Further, as the WC-Co system in which WC is added as a binder metal in addition to cobalt, WC-Ni-based, WC-TiC-based, WC-TaC-based, etc. may be mentioned, and these can be used in the present invention. The base layer 92 can be formed, for example, by thermal spraying. The thickness of the underlayer 92 is preferably in the range of, for example, 50 μm or more and 200 μm or less, and more preferably 70 μm or more and 130 μm or less. In addition, in each drawing, the thickness of the base layer 92 and the DLC film 86 is enlarged and compared with other members in the illustration relationship.

The base layer 92 is formed, for example, in the following manner. First, the sharpness of the wedge-shaped base 85 The portion of the base layer forming region is recessed. Next, a base layer 92 is provided in the base layer formation region. After the underlayer 92 is formed, the underlayer 92 is formed in the same level as the substrate 85 by mechanical processing such as polishing. The base layer forming process is performed in this manner.

As shown in Figs. 9 and 12, the maximum length of the cross section of the die 82 on the XY plane is LW, and the length of the die 82 in the Y direction is LY, the value of (LY/LW) is 50 or more and 400 or less, that is, 50. LW LY 400. LW is better. LY is preferably 1500 mm or more, and more preferably 2000 mm or more.

The mounting hole 95 penetrates the substrate 85 in the Z direction. A plurality of the mounting holes 95 are provided in the Y direction with a pitch therebetween. A screw hole 96 is provided in the die body 81 at a position corresponding to the mounting hole 95. In addition, in Fig. 12, the illustration of the DLC film 86 is omitted for simplification of the drawing.

The Vickers hardness Hv of the base layer 92 is greater than the Vickers hardness Hv of the base 85. Further, the Vickers hardness Hv of the base layer 92 is smaller than the Vickers hardness Hv of the DLC film 86. The Vickers hardness Hv of the base layer 92 is preferably 150 Hv or more. Further, the Vickers hardness Hv of the DLC film 86 is preferably 1000 Hv or more and 2500 Hv or less. Although the details will be described later, the Vickers hardness of the underlayer 92 and the DLC film 86 (Hv2-Hv1 to be described later) is preferably 500 Hv or less. The Vickers hardness Hv is a value converted according to the indentation hardness of ISO 14577 (Oliver & Pharr calculation method). In addition, in the following description, the Vickers hardness may be referred to as "hardness", and the Vickers hardness difference may be referred to as "hardness difference".

(DLC film)

As shown in FIG. 10, the DLC film 86 is provided on the entire surface of the substrate 85. However, in the present embodiment, the upper end surface 85b of the base 85 shown in Fig. 10 is attached to the fixing member 106 as shown in Fig. 14, so that the DLC film 86 is not formed on the upper end surface 85b. DLC The film 86 is formed by a known vapor phase film formation method. Since the amount of warpage of the processed die 82 is small, the heating temperature ΔT of the substrate 85 during the process is preferably 130 ° C or more and 300 ° C or less. This ΔT will be described later. Specific examples of the vapor phase film formation method include plasma CVD, ion plating, ion deposition, and the like, and ion deposition is preferred. The thickness d of the DLC film 86 is preferably in the range of, for example, 0.7 μm or more and 2 μm or less, and more preferably in the range of 1 μm or more and 2 μm or less.

As shown in Fig. 13, the DLC film forming apparatus 99 for forming a DLC film by ion deposition has a reflector 101, a filament 102, an anode 103, a target electrode 104, and an air guiding tube 105 in the processing chamber 100. The reflector 101 is formed, for example, in a cylindrical shape having a bottom. The anode 103 is disposed in the reflector 101 in a state of being electrically insulated from the reflector 101. The plasma source 107 is constituted by the three-pole structure of the filament 102, the anode 103, and the reflector 101. An air guide 105 is connected to the reflector 101. The reaction gas 108 such as hydrocarbon gas is sent from the air guide 105 to the reflector 101. A substrate 85 is mounted on the target electrode 104 via a fixture 106. The power supply unit 109 has a reflector power supply 109a, a filament power supply 109b, an anode power supply 109c, and a target power supply 109d. The power sources 109a to 109d apply a predetermined voltage to the connected reflector 101, the filament 102, the anode 103, and the target electrode 104.

As shown in Figs. 14 and 15, the fixing member 106 made of stainless steel is provided with a fixing plate 110 having a right-angled foot plate 111 on both sides, and a fixing of a size of, for example, M6 (JIS; Japanese Industrial Standards, Japanese Industrial Standard). Bolt 112. Screw holes 115 are arranged on the fixing plate 110 at intervals in the Y direction. The base 85 is fastened to the fixing member 106 by mounting the fixing bolt 112 to the screw hole 115 via the mounting hole 95.

As shown in Fig. 13, the reaction gas 108 is introduced from the air guiding tube 105 into the internal space of the reflector 101. The periphery of the anode 103 is plasma-generated by DC arc discharge. Hydrocarbon ions are generated from the reaction gas 108 due to the plasma. The generated hydrocarbon ions are directed toward the target electrode 104. Target electrode The substrate 85 is mounted on the 104, so that hydrocarbon ions collide with the substrate 85, and a DLC film 86 is formed on the substrate 85. Thereby, a DLC film formation process for forming the DLC film 86 on the substrate 85 by ion evaporation is performed in the DLC film forming apparatus 99.

The substrate 85 is heated to a predetermined temperature by ion evaporation. When the DLC film 86 is formed on such an elongated object as the die 82, a plurality of plasma sources 107 are arranged in the longitudinal direction in accordance with the length of the die 82, and ion deposition is performed on the entire length of the die 82. Therefore, as with the elongated object of the die 82, the number of the plasma source 107 increases as the length thereof becomes longer, and the number of electrodes also increases by a corresponding amount, so that the processing temperature in the DLC film forming process becomes high.

When the hardness of the DLC film 86 is adjusted, for example, in the ion evaporation method, it is carried out as follows. First, a hydrocarbon gas is used as a raw material, and carbon ions C ^{+ are} generated by vaporization of plasma or the like. By applying a cathode (-) voltage to the substrate 85, carbon ions are struck on the substrate 85 to form a DLC film 86. When the carbon ions collide with the substrate 85, the mixing ratio of the diamond film (Sp3 bonding) and the graphite film (Sp2 bonding) constituting the DLC film 86 changes depending on the collision energy of the carbon ions generated in the substrate 85. Further, the more the Sp3 bond in the DLC film 86, the harder the film becomes, and the more the Sp2 bond is, the more likely the film is to be obtained. With this tendency, the DLC film 86 having desired characteristics can be formed by adjusting the cathode voltage or the like applied to the substrate 85.

After performing ion evaporation, it was cooled to room temperature. Warpage in the substrate 85 is caused during this heating and cooling process. Therefore, fluorine coating is performed on the surface of the fixing plate 110. A fluorine film which is lower in friction than a forming material of the substrate 85 (for example, SUS316L) is provided on the surface of the fixing plate 110, and ion evaporation is performed in a state in which the substrate 85 is fixed via a low-friction fluorine film, whereby the substrate 85 is thereby provided. The warpage is suppressed, and the DLC film 86 can be formed on the substrate 85 (see Fig. 10).

In addition, the tightening torque of the fixing bolt 112 (refer to Fig. 15) is from the Y direction. It is preferable that the central portion gradually becomes smaller toward both ends in the Y direction. For example, the tightening torque of the central portion fixing bolt 112 in the central portion in the Y direction is 10N. m, and the tightening torque of the end fixing bolt 112 in the Y-direction end portion is 3N. m. Moreover, the tightening torque of the fixing bolt 112 between the central portion fixing bolt 112 and the end fixing bolt 112 is 5N. m. In this way, since the tightening torque becomes smaller as the end portion becomes smaller, the end portion of the base 85 becomes easy to move, and warping and cracking of the base 85 can be more reliably suppressed, and the DLC film 86 can be formed on the base 85. (See Figure 10).

Since the base 85 and the base layer 92 are made of different materials, the linear expansion coefficient α1 of the base 85 is different from the linear expansion coefficient α2 of the base layer 92. The difference between the two (α1 - α2) and the heating temperature (the processing temperature in the DLC film forming process - room temperature) ΔT when the DLC film is formed, when the DLC film 86 is formed, the temperature of the substrate 85 rises. The elongation of the two becomes different to cause a thermal expansion strain. The thermal expansion strain is strain due to thermal expansion of the substrate 85 and the base layer 92. If the stress σ1 of the thermal expansion strain base layer 92 exceeds the WC fracture stress σ2, for example, 820 MPa, the base layer 92 may be broken, and the base layer 92 and the DLC film 86 formed on the base layer 92 may be turtles. crack. As a result of the occurrence of the crack, the yield of the die 82 (the number of qualified products without cracking/the total amount of production) is lowered, and the production efficiency is lowered. Further, the fine cracks which have been neglected in the past cause peeling of the DLC film 86 during long-term use, and a streaky failure occurs in the film during film formation.

Therefore, as shown in Fig. 16, the die 82 is manufactured by the determination process 121 for the crack arresting suitable condition, the underlayer formation process 122, and the DLC film formation process 123. In the determination process 121 for the crack arresting suitable condition, the combination of the linear expansion coefficient of the base 85 and the base layer 92, the length LY of the longitudinal direction (Y direction) of the die 82, and the heating temperature at the time of forming the DLC film are changed, and each combination is performed. When the DLC film is formed, the substrate 85 and the base layer 92 are caused by the temperature rise. The external force of the thermal expansion strain determines the stress acting on the base layer 92, that is, the thermal expansion strain acts on σ1 of the base layer 92. When the stress σ1 reaches the breaking stress σ2 of the base layer 92, that is, 820 MPa or more, it is judged that cracks are generated in the combination. Further, when the obtained stress σ1 is less than 820 MPa, it is judged that no crack is generated. Further, the external force refers to a force generated by the compressive force PB acting on the base 85 and the traction force PL acting on the base layer 92, and is applied to each of the longitudinal directions. Specifically, it is calculated based on PB-PL.

The compressive force acting on the substrate 85 is set to PB, the traction force acting on the base layer 92 is set to PL, and the cross-sectional area of the base layer 92 in the cross section (the section along the XZ plane) orthogonal to the longitudinal direction of the die is set. In the case of AL, the stress σ1 acting on the base layer 92 is obtained from σ1 = (PB - PL) / AL.

The compressive force PB acting on the substrate 85 is obtained by the following method. First, the strain εB is obtained from the elongation ΔLYB caused by the heating temperature of the substrate 85 and the length LY of the substrate, that is, εB = ΔLYB/LY. Next, the Young's modulus EB of the base 85 is multiplied by the strain εB, and the vertical stress σB (σB = εB. EB) is obtained. The compressive force PB (PB = σ B. AB) is obtained by multiplying the obtained vertical stress σB by the cross-sectional area AB in the section along the XZ plane. The traction force PL of the base layer 92 was obtained in the same manner. First, the strain εL is obtained from the elongation ΔLYL caused by the heating temperature of the base layer 92 and the length LY of the substrate, that is, εL = ΔLYL/LY. Next, the Young's modulus EL is multiplied by the strain εL of the base layer 92 to obtain a vertical stress σL (σL = εL.EL). The traction force PL (PL = σL.AL) is obtained by multiplying the obtained vertical stress σL by the sectional area AL. Here, ΔLYB is subtracted from the length in the Y direction of the base 85 at the above-described heating temperature by the length in the Y direction before heating (non-heated state, that is, at room temperature). ΔLYL is subtracted from the length in the Y direction of the base layer 92 at the above heating temperature before heating (non-heated state, that is, The length in the Y direction at room temperature).

Further, as the length LY of the object, that is, the base 85, becomes long, it is necessary to gradually increase the number of the reflectors 101. Therefore, as the number of reflectors 101 increases, the number of electrodes also increases. Since the vacuum plasma discharge is performed by the electrode, the increase in the electrode is related to an increase in the processing temperature. As such, the processing temperature in the DLC film forming process 123 rises as the amount of increase of the reflector 101 corresponding to the length LY of the substrate 85 increases. Therefore, the heating temperature in the DLC film forming process 123 is determined in advance by experiments, or is determined based on the current processing performance data.

The determination of the suitable condition for arresting can be determined by the above formula, and a table calculation software (for example, Excel manufactured by Microsoft Corporation) can be used. At this time, as shown in the following Table 1, the length LY in the longitudinal direction of the substrate 85 to be used, the linear expansion coefficient α of the base 85 and the base layer 92, and the heating temperature ΔT when the DLC film is formed are input in each column. The values of the Young's modulus E, the cross-sectional area A, and the fracture stress σ2 of the base layer 92 are the results of the calculation, the elongation ε due to thermal expansion, the stress σ at the time of thermal expansion, the external force F at this time, and the thermal expansion strain. The calculated values are shown in each column of the tensile stress σ1 generated by the base layer 92. Comparing the obtained stress σ1 with the fracture stress σ2 (=820 MPa) of the base layer 92, when σ1 < σ2, it is judged that the combination value is appropriate, and as a result of the determination, when appropriate, it is displayed on the judgment column of the rightmost column. “Appropriate”, “Not suitable” when inappropriate. By using the table calculation software and inputting the numerical data and the size data based on the material of the die to be produced, it is possible to automatically determine whether the input value meets the appropriate conditions for the crack arrest.

When the combination satisfying the crack-free condition is obtained by the determination process 121 of the suitable conditions for arresting, under this condition, the base layer 92 is first formed by the base layer forming process 122, and then the process 123 is formed by the DLC film. The DLC film 86 is formed, whereby the die 82 which does not generate cracks can be reliably obtained.

Further, although not shown, an application for adding the comparison judgment and the data input guidance function can be incorporated into the computer instead of the numerical calculation by the table calculation software. At this time, the following functions are added to the computer to form an application, that is, the input guidance function of each of the above conditions, the function of calculating the stress σ1 according to the numerical values of the input conditions, the calculated stress σ1 and the fracture stress When σ2 is compared, when the stress σ1 is smaller than the fracture stress σ2, it is determined that the combination of the respective conditions is suitable for the judgment function; when the stress σ1 is greater than or equal to the fracture stress σ2 according to the comparison judgment, the crack is generated and an alarm is generated and re-inputted into each Conditional re-entry function.

Also, it may be an application that combines table calculation software. At this time, in addition to the input guide in the form of a table as shown in Table 1, the obtained stress σ1 is compared with the fracture stress σ2, and when σ1 < σ2, it is shown that the combination of the conditions becomes no crack. Suitable conditions. And σ1 At σ2, the numbers in each column are flashing to cause the value to change. In this case, when the appropriate condition is obtained in the direction in which the value rises, the value or the ▲ symbol is attached to the value, and when the appropriate condition is obtained in the direction in which the value is decreased, the numerical value is attached with the ↓ or the ▼ symbol, thereby making it easy to Modify the conditions. In addition to the numerical input, it is also possible to automatically calculate the extent to which the value is changed to meet the appropriate conditions, and display the value by changing the color, or it can be expressed in a manner close to the input value. At this time, it is also possible to perform automatic calculation by fixing one condition value and changing other values.

The difference in hardness between the base layer 92 and the DLC film 86 is 500 Hv or less, preferably 200 Hv or less, and more preferably 100 Hv or less. If the difference in hardness between the two is within a certain range of 500 Hv or less, the fact that the adhesion of the DLC film 86 to the underlying layer 92 is improved is judged by the experimental results. This must be because if the difference in hardness between the two interfaces is large, a difference will occur in the strain amount and the adhesion will be lowered. Further, when the hardness difference exceeds a certain value, the soft substrate such as SUS first collapses, and the DLC film 86 does not change with the change of the substrate to cause cracking.

Additionally, the DLC film 86 may be formed to be the entire surface of the substrate 85 or may be part of the front end.

In the above embodiment, the casting die 21 is configured by combining the pair of side plates 71 and the pair of die plates 72. However, the present invention is not limited thereto, and the flow may be formed only by the die plate 72, for example, the side plates 71 are omitted. The flow of the road 29 is extended. Further, the casting die may be constituted by a member other than the side plate 71 and the lip plate 72.

In the above-described embodiment, the casting film 34 is cooled in a state in which the casting film 34 can be independently conveyed. However, the present invention is not limited thereto, and the casting film 34 may be evaporating the film 34 by dry air. The solvent makes the cast film into a state capable of being independently transferred.

In the above embodiment, the casting drum 22 is used as the support, but a casting belt may be used instead. When a casting belt is used, the casting belt is circulated by winding a casting belt between a pair of rollers to rotate the drum.

In the present invention, the flow of the dope is delayed, and the two or more kinds of the concentrated liquid can be simultaneously co-cast and laminated, and the co-casting can be carried out or the plurality of dopes can be successively co-cast and laminated. In addition, it is also possible to combine two co-casts. When performing simultaneous laminating cocurrent delay, a casting die equipped with a feed head may be used, or a multi-channel casting die may be used.

In the solution film forming apparatus 10 of the present invention, the product has a width of 600 mm or more, more preferably 1400 mm or more and 2500 mm or less. In addition, the film has a width greater than 2500 mm and is also effective. Further, the film thickness of the film is preferably 15 μm or more and 80 μm or less. The polymer which is a raw material of the polymer film is not particularly limited, and examples thereof include cellulose halides and cyclic polyolefins.

The amino group used in the cellulose halide of the present invention may be only one type, or two or more types of amino groups may also be used. When two or more kinds of amino groups are used, one of them is preferably an ethyl group. The ratio of the hydroxyl group of the cellulose esterified with a carboxylic acid, that is, the degree of substitution of the amino group, satisfies all of the following formulas (I) to (III). Further, in the following formulas (I) to (III), A and B represent the degree of substitution of an amino group, A is a degree of substitution of an acetyl group, and B is a degree of substitution of a fluorenyl group having 3 to 22 carbon atoms. Further, it is preferred that 90% by mass or more of triacetylcellulose (TAC) is 0.1 mm to 4 mm.

The total substitution degree A+B of the amino group is preferably 2.20 or more and 2.90 or less, and more preferably 2.40 or more and 2.88 or less. Further, the degree of substitution B of the fluorenyl group having 3 to 22 carbon atoms is preferably 0.30 or more, and particularly preferably 0.5 or more.

The details of the cellulose halide are described in paragraphs [0140] to [0195] of Japanese Patent Laid-Open Publication No. 2005-104148. The contents described herein are also applicable to the present invention. Further, the details of the additives such as a solvent, a plasticizer, a deterioration inhibitor, an ultraviolet absorber (UV agent), an optical anisotropy controlling agent, a retardation inhibitor, a dye, a matting agent, a release agent, and a peeling accelerator are the same. Also in paragraph [0196] to [051 of Japanese Patent Publication No. 2005-104148 It is recorded in paragraph 6].

[Examples]

(Experiment 1)

In the DLC film forming apparatus 99 shown in Fig. 13, a DLC film 86 is formed on the substrate 85 shown in Fig. 12 by ion deposition to obtain a die 82 (see Fig. 10). The base 85 is made of SUS316L as a whole, and a casting die having a WC-Co base layer 92 at the lower end portion 85a is used. The base layer 92 was formed by WC thermal spraying, and the hardness Hv was 1,500, and the coefficient of linear expansion was 8 × 10 ^-6 / ° C. The linear expansion coefficient of the substrate 85 was 16 × 10 ^-6 / ° C, and the difference in linear expansion coefficient between the base layer 92 and the substrate 85 was 8 × 10 ^-6 / ° C. Regarding the substrate 85, the length LX was 20 mm, the length LY was 2000 mm, the length LZ was 20 mm, and the maximum length LW in the cross section on the XY plane was 28 mm. The substrate 85 is fixed to the target electrode 104 by a fixing member 106 (see FIGS. 14 and 15) provided with a fluorine film on the surface of the fixing plate 110 made of stainless steel (SUS316L). The heating temperature ΔT of the substrate 85 in the cured film forming process was 180 °C. The thickness d of the DLC film 86 was 1.6 μm, and the hardness Hv was 2000 Hv. The difference in hardness between the base layer 92 and the DLC film 86 was 500 Hv.

(Experiment 2~11)

In Experiments 2 to 11, the DLC film 86 was formed on the substrate 85 in the same manner as in Experiment 1 except for the conditions shown in Table 2 to obtain a die 82.

Table 2 shows the length LY (mm) of the base 85 in Experiments 1 to 11, the material of the base 85, the coefficient of linear expansion α1, the material of the base layer 92, the coefficient of linear expansion α2, the hardness of the Hv1, and the hardness of the DLC film 86. Hv2, heating temperature ΔT (°C). Hardness refers to Vickers hardness Hv.

In Experiment 2, the length LY of the substrate 85 was set to 2200 mm so as to be 700 mm longer than Experiment 1. The heating temperature ΔT of the DLC film forming process was also 60 ° C higher than that of Experiment 1, and was 240 ° C. The conditions were the same as in Experiment 1. The difference in hardness between the base layer 92 and the DLC film 86 was 500 Hv as in Experiment 1.

In Experiment 3, the length LY of the substrate 85 was set to 2700 mm, and the material was changed to SUS329J1. The linear expansion coefficient α1 of the substrate 85 becomes 12×10 ^-6 /° C., and the heating temperature ΔT of the DLC film forming process also becomes 90° C. higher than that of the experiment 1 and becomes 270° C. The conditions were set to be the same as in Experiment 1. The difference in hardness between the base layer 92 and the DLC film 86 was 500 Hv as in Experiment 1.

In Experiment 4, the length LY of the substrate 85 was set to 3000 mm, and the material was changed to SUS630. The linear expansion coefficient α1 of the substrate 85 becomes 12×10 ^-6 /° C., and the heating temperature ΔT of the DLC film forming process also becomes 105° C. higher than that of the experiment 1 and becomes 285° C. The conditions were set to be the same as in Experiment 1. The difference in hardness between the base layer 92 and the DLC film 86 was 500 Hv as in Experiment 1.

In Experiment 5, the length LY of the substrate 85 was set to 1800 mm so as to be 300 mm longer than Experiment 1. The heating temperature ΔT of the DLC film formation process also became 20 ° C higher than that of Experiment 1, and became 200 ° C, and the hardness of the obtained DLC film was 1,700 Hv. Otherwise, the conditions were the same as in Experiment 1. The difference in hardness between the base layer 92 and the DLC film 86 was 200 Hv lower than that of Experiment 1.

In Experiment 6, the length LY of the substrate 85 was set to 1700 mm to make it Experiment 1 was 200 mm long. The heating temperature ΔT of the DLC film forming process was also 20 ° C higher than that of Experiment 1, and was 200 ° C, and the hardness of the obtained DLC film was 1400 Hv. Otherwise, the conditions were the same as in Experiment 1. The difference in hardness between the base layer 92 and the DLC film 86 was -100 Hv lower than that of Experiment 1.

In Experiment 7, the length LY of the substrate 85 was set to 3000 mm so as to be 1500 mm longer than Experiment 1. The heating temperature ΔT of the DLC film formation process was also 135 ° C higher than that of Experiment 1, and the conditions were the same as in Experiment 1. The difference in hardness between the base layer 92 and the DLC film 86 was 500 Hv as in Experiment 1.

In Experiment 8, the length LY of the substrate 85 was set to 1800 mm so as to be 300 mm longer than Experiment 1. The heating temperature ΔT of the DLC film forming process was also 20 ° C higher than that of Experiment 1, and was 200 ° C, and the hardness of the obtained DLC film 86 was 1,100 Hv. Otherwise, the conditions were the same as in Experiment 1. The difference in hardness between the base layer 92 and the DLC film 86 was -400 Hv lower than that of Experiment 1.

In Experiment 9, the heating temperature ΔT of the DLC film forming process was 170 ° C, and the hardness of the obtained DLC film was 2700 Hv, except that the conditions were the same as in Experiment 1. The difference in hardness between the base layer 92 and the DLC film 86 was 1200 Hv higher than that of Experiment 1.

In Experiment 10, the base layer 92 was not formed on the substrate 85, and the DLC film 86 was formed directly on the substrate 85. Otherwise, the conditions were the same as in Experiment 5.

In Experiment 11, the conditions were set to be the same as in Experiment 10 except that the substrate made of a nickel-based hard material (WC-Ni) was used instead of SUS316L in Experiment 10.

(Evaluation)

The following evaluations were performed on the die 82 obtained by Experiments 1-11. In Table 2, the numbers shown in the evaluation items indicate the numbers attached to the following evaluation items.

Cracking of DLC film

The DLC film 86 was examined for cracks. For the presence or absence of cracking, a microscope VH-900 manufactured by Keyence Corporation was used, and observation was performed by magnifying the magnifying lens 100 times to see whether or not cracks were present and the length was determined. The evaluation was based on the following criteria based on the presence or absence of cracks and the length.

A: No cracks were produced.

B: There is a crack and its length is 100 μm or less.

C: There is a crack, and its length is more than 100 μm.

2. Die warping

Regarding the die 82, the amount of warpage W was measured. First, the die 82 is placed on the base with the curved portion facing downward. The largest gap in the gap between the die 82 and the base is taken as the amount of warpage W. The warpage amount W was evaluated based on the following criteria.

A: W is 5 μm or less.

B: W is more than 5 μm and is 15 μm or less.

C: W is larger than 15 μm.

3. Friction and wear strength of DLC film

The DLC film 86 was subjected to a friction and wear test, and after the test, the DLC film 86 was visually observed, and the strength of the DLC film 86 was evaluated in accordance with the following criteria. The friction and wear test was performed in the following order. A friction wear test (JIS R 1613-1993) was conducted using a Tribometer (ball-to-disk type) manufactured by CSM Instruments. First, a test piece (50 mm × 20 mm × 10 mm) from which a part of the die 82 was cut was fixed on a rotary table, and the rotary table was rotated at a prescribed rotational speed. Next, at the position of the front end portion of the die 82 and having a DLC film 86 of 3.0 mm from the center of rotation, the front end was pressed into a spherical (diameter of 6.35 mm) Al ₂ O ₃ disk at a predetermined load (5.0 N). Disk ball (test piece). The speed of the DLC film 86 in the pressed position was 0.1 m/sec. The die 82 was rotated at 20,000 rpm in a state where the ball was pressed. Thereafter, the amount of wear of the DLC film 86 caused by the disk was measured by a surface roughness meter (SURFCOM 2000DX3) manufactured by TOKYO SEIMITSU CO., LTD. Based on the amount of wear, the evaluation was performed based on the following criteria.

A: The wear amount is “O” and there is no wear.

B: The amount of wear is 100 nm or less.

C: The amount of wear is greater than 100 nm.

4. Adhesion evaluation of DLC film

The DLC film 86 was subjected to a scratch test, and the adhesion of the DLC film 86 was evaluated. A Revify (scratch tester) manufactured by CSM Instruments was used in the scratch test. A diamond indenter (N2-3962) having a radius of curvature of 200 μm was used and evaluated under the following conditions. First, a load load of 100 N/min was applied to the DLC film 86 with a diamond stamper and the DLC film 86 was scraped at a moving speed of 10 nm/min. In the wiping process, if the DLC film 86 is broken, the wiping object is changed from the DLC film 86 to the WC film of the base layer 92. At this time, the friction coefficient of the DLC film 86 is 0.1, and the friction coefficient of the WC film is 0.4, and the change in the frictional resistance can be measured. If the change in the frictional resistance exceeds a certain value, the fact that the DLC film 86 is broken is sensed. Further, the critical load of the layered delamination in which the DLC film 86 is broken is defined as adhesion.

If it takes a certain time to calculate the friction coefficient by the scratch tester and the load according to the load, accurate adhesion (stress at which the DLC film 86 is broken) cannot be obtained. Therefore, when the DLC film 86 is broken, the elastic wave emitted when the damage is sensed by the AE (sound wave emission) sensor, The time during which the DLC film 86 is destroyed is accurately recorded, thereby obtaining more accurate adhesion data. Further, the initial load was set to 0.9 N, the load load was set to 100 N/min, the moving speed was set to 10.0 mm/min, and the sensitivity of the AE sensor was set to 9. In the actual application, when the adhesion of the DLC film 86 in the evaluation method is 30 N or more, it is determined that the DLC film 86 is not peeled off and is stable. The adhesion was evaluated based on the following criteria.

A: Adhesion exceeds 30N.

B: Adhesiveness is greater than 20 N and is 30 N or less.

C: Adhesion is 20 N or less.

In Experiments 1, 3, and 4, the crack, warpage, and strength were "A", and the adhesion became "B". In Experiment 2, the strength was "A", and the crack, warpage, and adhesion were "B". In Experiment 5, cracks, warpage, strength, and adhesion were all "A". In Experiment 6, the crack, warpage, and adhesion were "A", and the strength was "B". In Experiment 7, the crack and warpage were "C", the strength was "A", and the adhesion was "B". In Experiment 8, the crack, warpage, and adhesion were "A", and the strength was "C". In Experiments 9, 10, the crack, warpage, and strength were "A", and the adhesion became "C". In Experiment 11, cracks, warpage, strength, and adhesion were all "A".

When SUS316L was used as the material of the base 85, in Experiment 1 in which the base length LY was 1500 mm, the crack, the warpage, and the strength were both "A", and the adhesion was B, and the evaluation was as the base length LY became longer. Reduce the trend. For example, when the substrate length LY is increased to 2200 mm (Experiment 2), it is judged that the evaluation of warpage and cracking is lowered to "B", and cracking of 100 μm or less is caused. Further, when the base length LY was increased to 3000 mm (Experiment 7), it was judged that only the strength was evaluated as "A", the warpage and crack evaluation were "C", and the adhesion evaluation was "B".

In Experiment 3 and Experiment 4, the material of the substrate was changed from SUS316L to SUS329J1 and SUS630. At this time, even if the base length LY is increased to 2700 mm and 3000 mm, a crack, warp, strength "A", and adhesion "B" can be obtained.

Compared with the experiment 1, the base length LY of the experiment 5 was increased by 300 mm to 1800 mm, the heating temperature of the DLC film 86 was 200 ° C, and the hardness Hv2 was 1,700. Otherwise, the other conditions were the same as those of the experiment 1. At this time, the hardness difference Hv2-Hv1 between the DLC layer and the base layer 92 was 200, and a die having a crack, warpage, strength, and adhesion of "A" was obtained.

The base length LY of the experiment 6 was increased by 200 mm to 1700 mm in comparison with the experiment 1, and the heating temperature of the DLC film 86 was 200 ° C and the hardness Hv2 was 1400. Other conditions were the same as those of the experiment 1. At this time, the hardness difference Hv2-Hv1 between the DLC layer and the base layer 92 was -100, and a crack having a crack, warpage, adhesion of "A" and strength of "B" was obtained.

Compared with Experiment 4, the die of Experiment 7 was the same die as Experiment 4 except that the material was changed to SUS316L. At this time, cracks and warps were obtained, C became strong, and the adhesion became B. Since the crack and the warpage are C, when it is used as a film forming mold, in addition to the durability problem, there is a problem that streaks are formed on the surface of the produced film due to the peeling of the base layer 92.

The die of Experiment 8 was the same as that of Experiment 5 except that the hardness Hv2 of the DLC film 86 was set to 1100 as compared with Experiment 5. At this time, the hardness difference Hv2-Hv1 between the base layer 92 and the DLC film 86 is -400, and a crack, warpage, and adhesion are obtained, and the strength becomes C. Since the strength is C, when it is used as a mold for film formation, there is a problem in durability.

Compared with Experiment 1, the die of Experiment 9 was in addition to the hardness of the DLC film 86. Hv2 was set to 2700, and the heating temperature was set to 170 ° C, and the other conditions were the same as in Experiment 1. At this time, the hardness difference Hv2-Hv1 between the base layer 92 and the DLC film 86 was 1200, and cracks and warpage were obtained, and the strength became A, and the adhesion became C. Since the adhesiveness is C, there is a problem in durability when used as a mold for film formation.

The die of Experiment 10 was the same die as Experiment 5 except that the DLC film 86 was formed directly on the substrate without forming the base layer 92 on the substrate 85. In the experiment 10, the difference in hardness between the DLC film 86 and the member in contact therewith was 1,800, and the adhesion was determined to be lower than that of the experiment 5.

The die of Experiment 11 was the same die as that of Experiment 10 except that the substrate made of a nickel-based hard material was used instead of the substrate of SUS316L of Experiment 10. In the experiment 11, the difference in hardness between the DLC film 86 and the member in contact therewith was 600, and the adhesion was determined to be A as compared with the experiment 10.

As in Experiment 11, the substrate itself is composed of a hard material by not providing the underlayer, and the stress caused by the thermal expansion strain of the substrate and the underlayer does not occur when the DLC film is formed, and thus no crack is generated in the DLC film 86 or The adhesion of the DLC film 86 is lowered due to cracking. Thereby, the durability of the casting die is improved, and generation of a streaky failure can be suppressed.

Next, the results of the suitability of the conditions in the above experiments according to the numerical calculation table are shown in Table 3.

From the results of Table 3, it was judged that the determination results of the appropriate conditions were consistent with the crack evaluations in the above experiments 1 to 9. Therefore, in the production of the target, depending on the material to be used, the combination of the mechanical properties and the length corresponding to the material, it is possible to confirm the occurrence of cracks before the production, and to avoid a decrease in the yield. Further, since cracking does not occur, peeling of the DLC film 86 due to frequent use due to minute cracks is also lost, and a film which does not cause streaky failure can be efficiently produced.

82‧‧‧die

85‧‧‧Base

85b‧‧‧ upper end

86‧‧‧DLC film

92‧‧‧ basal layer

95‧‧‧Installation holes

d‧‧‧DLC film thickness

X, Z‧‧‧ direction

Claims (11)

A casting die having a separable die at a dope outlet and allowing a dope to flow out to a support, wherein the dope comprises a polymer and a solvent, wherein the die comprises: a base made of stainless steel; and a base layer is provided on The base layer is formed of a hard material; the diamond-like carbon film is disposed on the base layer by a vapor phase film formation method; and the linear expansion coefficients of the substrate and the base layer having a σ1 smaller than σ2, a combination of a length of a longitudinal direction of the die and a heating temperature at which the carbon-like carbon film is formed, wherein σ1: thermal expansion of the substrate and the base layer by temperature rise when the diamond-like carbon film is formed The strain acts on the stress of the aforementioned base layer; σ2: the fracture stress of the aforementioned base layer. The casting die according to claim 1, wherein a compressive force acting on the base is PB, and a traction force acting on the base layer is PL, which is orthogonal to a longitudinal direction of the die. When the cross-sectional area of the underlying layer in the cross section is set to AL, the stress σ1 acting on the underlying layer is obtained from σ1 = (PB - PL) / AL. The casting die according to the second aspect of the invention, wherein the length of the longitudinal direction of the die is LY, and the maximum length of the cross section orthogonal to the longitudinal direction is LW, LY 50. In LW, the length LY is 1500 mm or more, the thickness of the underlayer is 70 μm or more and 130 μm or less, and the thickness of the diamond-like carbon film is 0.7 μm or more and 2 μm or less. A casting die according to any one of claims 1 to 3, wherein The aforementioned substrate is formed of any one of SUS316L, SUS329J1, and SUS630, and the base layer is formed of tungsten carbide. The casting die according to any one of claims 1 to 3, wherein a difference in hardness between the base layer and the diamond-like carbon film is within 500 Hv. The casting die according to claim 5, wherein the diamond-like carbon film has a hardness of 1300 Hv or more. The casting die according to any one of the items 1 to 3, wherein the vapor phase film formation method is any one of ion deposition, ion plating, and plasma chemical vapor deposition. A method for producing a film, comprising the steps of: forming a film composed of the dope by flowing a dope from a casting die to a support, wherein the dope comprises a polymer and a solvent, and the casting die a die capable of separating at a dope outlet, the die having a base, a base layer, and a diamond-like carbon film, wherein the base is made of stainless steel, the base layer is provided on the base, and the base layer is formed of a hard material, The diamond-like carbon film is provided on the base layer by a vapor phase film forming method, and the die has a linear expansion coefficient of the substrate and the base layer such that σ1 is smaller than σ2, and a length and a length of the longitudinal direction of the die. a combination of heating temperatures when the carbon-like film is drilled; a step of evaporating the solvent from the film until the film can be independently transported; a step of stripping the film from the support as a wet film; and causing the solvent to be from the foregoing a step of evaporating the wet film as a film, wherein σ1: the foregoing substrate and the foregoing substrate are caused by an increase in temperature when forming the aforementioned diamond-like carbon film The thermal expansion of the stress acting on the strain of the base layer; Σ2: the breaking stress of the aforementioned base layer. A method for producing a die, wherein the die is attached to an elongated column of a dope outlet of a casting die through which a dope flows out, wherein the dope contains a polymer and a solvent, and the method for manufacturing the die includes the following steps (A) a step of forming a base layer on a base made of stainless steel, the base layer being formed of a hard material; (B) a step of forming a diamond-like carbon film on the base layer by a vapor phase film formation method; and C) a step of determining a combination of each of the linear expansion coefficients of the base layer and the base layer, the length of the longitudinal direction of the die, and the heating temperature in the gas phase film formation method before the step A, wherein the combination is The σ1 is smaller than σ2, wherein σ1 is a stress acting on the base layer by the thermal expansion strain of the substrate and the base layer in the foregoing step B; σ2: a fracture stress of the base layer. The method for manufacturing a die according to claim 9, wherein the compressive force acting on the base is PB, and the traction force acting on the base layer is PL, and the longitudinal direction of the die is positive. When the cross-sectional area of the underlying layer in the cross section is set to AL, the stress σ1 acting on the underlying layer is obtained from σ1 = (PB - PL) / AL. The method for producing a die according to claim 9, wherein the vapor phase film formation method is any one of ion deposition, ion plating, and plasma chemical vapor deposition.