JP5151938B2 - Method for producing metal foil laminated film - Google Patents

Description

  The present invention relates to a method for producing a metal foil laminated film.

  In recent years, electronic devices such as mobile phones, displays, and digital cameras have been rapidly reduced in size, weight, and thickness. Along with this, there is an increasing demand for flexible circuit boards that are excellent in folding resistance, lightweight and heat resistant. Among the flexible circuit boards, in liquid crystal driver mounting applications for displays, heat resistance for mounting semiconductor chips at high temperatures is required in addition to bending resistance, weight reduction, and ease of forming fine circuits. For this reason, the metal foil laminated film which uses a highly heat-resistant polyimide resin as a base film is often used. As a method for producing a metal foil laminated film, there are a plating method, a casting method, and a laminating method. Of these, the plating method is difficult to form a thick copper foil, and the casting method is difficult to form a thick polyimide resin layer. The laminating method has an advantage that it can be produced at high speed without being restricted by the above-mentioned manufacturing restrictions, and is promising. However, appearance defects such as wrinkles, wrinkles, and voids may occur by laminating at a high temperature, and it is difficult to maintain the appearance quality.

For this reason, the manufacturing method of the flexible metal plate which provided the means to expand an adhesive film in the width direction in front of the heating roll which bonds metal foil and an adhesive film is proposed (for example, refer patent document 1). Moreover, in order to improve dimensional stability, the manufacturing method of the flexible metal-clad laminated board which makes an adhesive film and metal foil contact a heating roll previously before heat pressurization is proposed (for example, refer patent document 2).
JP 2003-1754 A JP 2005-166849 A

  However, even if the above method is used, it is impossible to remove the slack due to the heat of the laminated material, and there is a problem that voids are generated. In view of the above-mentioned problems, an object of the present invention is to provide a method for producing a metal foil laminated film with a reduced appearance and a good appearance.

The present invention is a method for producing a metal foil laminated film in which at least a metal foil and an adhesive layer are laminated by heating and pressing,
(1) Step of preheating metal foil or adhesive layer (2) Step of stretching preheated metal foil or adhesive layer in TD direction (3) Step of laminating metal foil and adhesive layer by heating and pressing in this order a method for producing a metal foil laminated film, which comprises carrying out in.

  By this invention, generation | occurrence | production of a void can be suppressed and the metal foil laminated film with a favorable external appearance can be provided.

  The metal foil laminated film in the present invention has at least a metal layer and an adhesive layer. You may have a metal layer, an adhesive layer, and a heat resistant resin layer in this order. FIG. 1 is a schematic view showing one embodiment of the structure of the metal foil laminated film obtained by the present invention. This is a single-sided metal foil laminated film in which a heat-resistant resin layer 103 is laminated on one side of the metal layer 101 via an adhesive layer 102. FIG. 2 is a schematic view showing another embodiment of the structure of the metal foil laminated film obtained by the present invention. This is a double-sided metal foil laminated film in which the metal layer 101 is laminated on both sides of the heat-resistant resin layer 103 with the adhesive layer 102 interposed therebetween. FIG. 3 is a schematic view showing another embodiment of the structure of the metal foil laminated film obtained by the present invention. This is a double-sided metal foil laminate film in which the metal layer 101 is laminated on both sides of the adhesive layer 102.

The present invention is a method for producing a metal foil laminated film having the above structure,
(1) Step of preheating metal foil or adhesive layer (2) Step of stretching preheated metal foil or adhesive layer in TD direction (3) Step of laminating metal foil and adhesive layer by heating and pressing in this order It is characterized by being performed . By preheating the laminated material such as the metal foil and the adhesive layer in the step (1), appearance defects such as dimensional changes and wrinkles due to thermal expansion during thermocompression bonding can be suppressed. However, when the material to be laminated is heated and pressurized in the step (3) in a state where there is a sag due to the thermal expansion generated in the step (1), a void may be generated due to the bite of the sag. Therefore, the present invention eliminates the sag generated by stretching the layered material in the TD direction by the step (2) while the sag due to thermal expansion is generated in the layered material in the step (1). be able to. That is, it is possible to remove slack of the material to be laminated by stretching the preheated material to be laminated in the step (2), and greatly reduce the generation of voids by biting of the slack in the step (3). . On the other hand, when only the stretching in the TD direction is performed in the step (2) without going through the preheating step (1), the material to be laminated does not generate sagging due to heat, so this should be removed. I can't. Since the material to be laminated is rapidly heated in the subsequent step (3), sagging due to thermal expansion occurs, and the sagging of the sagging during heating and pressurization causes wrinkles, breaks, and voids. Therefore, in the present invention, it is important to provide the TD stretching step (2) after the preheating step (1). Note that the material to be laminated refers to a metal foil or an adhesive layer, and when it has other layers, it may be included.

  (1) The process of preheating the metal foil or the adhesive layer will be described. (1) By causing the material to be laminated to sag due to thermal expansion in advance by the preheating step, (2) sag due to thermal expansion can be removed in the TD stretching step. (1) If the laminated material is rapidly raised from room temperature to the heating temperature at the time of heating and pressurization without providing a preheating step, an elongation of several mm may occur. (3) Although it is relieved to some extent in the process of laminating the metal foil and the adhesive layer by heating and pressing, which will be described later, an elongation of 1 mm or more becomes thermal sagging, wrinkles are generated, or air bubbles that are bitten become voids. It remains at the interface between the metal layer and the adhesive layer. The preheating temperature is preferably close to the heating temperature in the step of (3) laminating the metal foil and the adhesive layer by heating and pressing, specifically, the heating temperature in the step of (3) is preferably within ± 100 ° C., Within 50 ° C. is more preferable. By setting the preheating temperature in the above range, it becomes easy to set the temperature of the material to be laminated in the step (2) described later within the heating temperature ± 100 ° C. in the step (3).

  The preheating method is not limited, and examples of the heating device include a non-contact type preheating device such as an infrared heater, a halogen heater, and electromagnetic induction heating, and a contact type preheating device using a dielectric heating roll. Moreover, you may use the heating-pressing member in the process (3) mentioned later as a heating apparatus. That is, the laminated material may be preheated by bringing the laminated material into contact with the heating and pressing member directly or indirectly through a protective film or the like. From the viewpoint of protecting the laminated material, a non-contact type heating device is preferable. You may heat from the front and back both sides of a laminated material, and may heat from one side. On the other hand, the method of preheating the material to be laminated with the heating and pressing member is preferable because the temperature uniformity of the material to be laminated is excellent and appearance defects such as wrinkles can be further reduced. Moreover, when using a protective film in the process of (3) mentioned later, adhesiveness with a protective film improves.

  The preheating time may be selected so that the material to be laminated is sufficiently preheated. For example, when preheating is performed at a temperature exceeding 200 ° C., in order to prevent oxidation of the laminated material, it is preferable that the preheating time after the laminated material exceeds 200 ° C. be within 10 seconds. Is more preferable. When the material to be laminated is preheated by the heating and pressing member, it is preferable to preheat the material to be laminated to the same temperature as the heating and pressing member, that is, the heating temperature in the step (3).

  (1) The laminated material to be preheated in the preheating step may be either a metal foil or an adhesive layer, or both. Moreover, when the material to be laminated includes other layers such as a heat resistant resin layer, these may be preheated together. In the present invention, it is preferable to preheat at least the metal foil, and it is more preferable to preheat both the metal foil and the adhesive layer. In general, a metal foil having a higher elasticity than the adhesive layer is less likely to expand and contract in the heating and pressurizing step (3), and therefore, wrinkles and creases due to sagging are likely to occur. Therefore, by preheating the metal foil, the effect of the present invention is more remarkably exhibited.

  Next, (2) the process of extending the preheated metal foil or adhesive layer in the TD direction will be described. This step is a step of eliminating the thermal sag generated in the laminated material in the (1) preheating step by stretching the laminated material in the TD direction. (2) The stretching step may be performed simultaneously with (1) the preheating step, or (1) may be performed after the preheating step. Further, (2) the laminated material to be stretched in the stretching step may be either a preheated metal foil or an adhesive layer, but it is preferable to stretch both. Moreover, when the material to be laminated includes other layers such as a heat resistant resin layer, these may be stretched together.

(2) The temperature of the laminated material stretched in the stretching step is close to the heating temperature in the step of laminating the metal foil and the adhesive layer by heating and pressing, which will be described later, as in the (1) preheating step. Is preferred. Specifically, it is preferable that the difference t of the temperature t _p and the heating pressurizing temperature t ₀ of time TD stretching at the measurement point 215 shown in FIG. 4 is within 100 ° C.. Thereby, the sag by the temperature change in the process of (2) and the process of (3) is reduced, and the effect of this invention is show | played more notably. More preferably, it is within 50 ° C. (2) By setting the temperature in the stretching step within the above range, wrinkles and creases can be suppressed, and the generation of voids can be further reduced.

  (2) In order to make the temperature of the laminated material stretched in the stretching step equal to the preheating temperature in the (1) preheating step, the interval between the (1) preheating step and (2) the stretching step is preferably within 1 m, more preferably Is within 50 cm. Moreover, you may heat a laminated material in a (2) extending | stretching process.

  Examples of the stretching method include a method of stretching a material to be laminated in a TD direction on a heating and pressing member, and a method of stretching during conveyance to a heating and pressing process using a cross guider roll or an expander.

  FIG. 5 shows an example of a method of stretching the material to be laminated on the heating and pressing member in the TD direction using a cross guider roll. By sandwiching the end of the material to be laminated such as the metal foil 210 and the resin layer 211 for lamination between the cross guider roll 208 and the laminating roll 204 arranged at a certain angle in the traveling direction of the material to be laminated, the material to be laminated Can be stretched in the TD direction. The cross guider roll 208 preferably has an appropriate frictional force against the material to be laminated under a high temperature condition, and preferably has a surface coated with a heat resistant material such as silicon rubber or viton rubber. In order to suppress the generation of foreign matter due to surface wear, the cross guider roll 208 is preferably disposed at an angle of 10 ° or less with respect to the TD direction.

  FIG. 6 shows a method of stretching the material to be laminated in the TD direction on the heating and pressing member using a touch roll. By sandwiching a material to be laminated such as the metal foil 210 and the resin layer 211 for lamination between the touch roll 208 and the laminating roll 204 with unevenness and curvature, the material to be laminated can be stretched in the TD direction. The touch roll 208 is preferably coated on the surface with a heat-resistant material such as silicon rubber or Viton rubber in the same manner as the cross guider roll 208 described above. Further, those having cushioning properties are also preferably used. In the case of using a touch roll formed with a curve, it is preferable to arrange the center portion in the width direction of the touch roll in the flow direction of the material to be laminated and the both end portions to flow from the flow direction toward both ends. Can be more effectively stretched in the TD direction. Moreover, as a touch roll in which the unevenness | corrugation was formed, the thing etc. which have arrange | positioned the material which has elasticity in the diagonal stripe shape from the width direction center part to the edge part of a touch roll, etc. are mentioned, for example. A slight torque may be applied to the touch roll.

  The method of performing TD stretching using a cross guider roll during conveyance to the heating and pressurizing process is such that a small pair of rolls called cross guider rolls are attached to both ends of the laminated material with respect to the traveling direction of the laminated material. In this method, the material to be laminated is stretched in a direction (TD direction) perpendicular to the traveling direction. In addition, the method using an expander is a method in which a material to be laminated is wound around an expander roll having a structure in which the roll surface extends outward in the axial direction of the roll with rotation at a certain winding angle, and the material to be laminated is rotated by rotating the roll. This is a method of stretching in the TD direction. Compared to the expander method, which requires a holding angle, the cross guider method is preferably used because it is generally easy to downsize. Further, the cross guider method in which both ends are sandwiched and stretched is preferable because the apparatus does not directly contact portions other than both ends of the material to be laminated. Moreover, it is also preferable to heat a cross guider roll or an expander roll, and it becomes easy to keep the temperature of a laminated material in a preferable range.

  (2) The tension of the material to be laminated in the stretching step is preferably 0.1 N / m or more, more preferably 0.2 N / m or more in the TD direction component. Further, the tension in the TD direction is preferably proportional to the tension in the MD direction of the material to be laminated. This is because the tension in the TD direction required for taking the slack increases as the tension in the MD direction of the laminated material increases. Specifically, the ratio between the tension in the TD direction and the tension in the MD direction (TD direction tension [N / m] / MD direction tension [N / m]: hereinafter referred to as tension ratio R) is 0. It is preferable that it is 0012 or more and 0.1 or less. When the tension ratio R is 0.0012 or more, it becomes easy to remove the slack due to the tension in the MD direction by the tension in the TD direction. In order to stably apply a tension in the TD direction to the material to be laminated, it is more preferably 0.002 or more, and further preferably 0.0033 or more. Moreover, if it is 0.1 or less, it can convey stably, suppressing the position shift of the laminated material by the tension | tensile_strength dispersion | variation in TD direction. More preferably, it is 0.067 or less.

  The tension in the TD direction can be adjusted by changing the nip pressure and the angle with respect to the traveling direction in the cross guider system. Even when the material to be laminated is stretched in the TD direction using a cross guider roll on the heating and pressing member, the tension in the TD direction can be similarly adjusted. Also, the tension in the TD direction can be adjusted by changing the frictional force on the surface of the cross guider roll. In the case of the expander method, it is easy to change the holding angle to the expander roll, but it is also possible to adjust the tension in the TD direction by changing the stretch amount of the expander roll.

A method for measuring tension by the cross guider method will be described with reference to FIG. The laminate roll and the previous distance L [mm] apart two pairs of rolls between the rolls, the "Kapton (registered trademark)" 150EN film 50mm the running position in the width direction is fixed, the tension _{T MD} in the MD direction Carry at [N / m] at the actual speed. Next, the parallel movement distance a [mm] of the film when the cross guider roll 208 is used is measured at the midpoint between the two sets of rolls. At this time, the tension T _TD [N / m] of TD stretching by the cross guider roll 208 is a value represented by the following formula.
T _TD [N / m] = T _MD [N / m] × a [mm] ÷ (L [mm] ÷ 2).

A method for measuring tension when the material to be laminated is stretched in the TD direction on a laminate roll will be described with reference to FIG. The speed at which a 50 mm “Kapton” 150EN film, in which the running position in the width direction is fixed by two sets of rolls separated by a distance L [mm], is applied with a tension T _MD [N / m] in the MD direction. Carry in. Next, when the “Kapton” 150EN film is sandwiched between the fixed SUS plate 214 and the cross guider roll 208 arranged at a fixed angle in the TD direction at the midpoint between the two sets of rolls, the parallel movement distance a of the film a [M] is measured, and the TD stretching tension T _TD [N / m] is calculated in the same manner as described above.

  Although the tension in the MD direction of the metal foil or the resin layer for lamination varies depending on the width and thickness of the material, the metal foil is generally preferably 10 N / m or more because it can be stably conveyed. On the other hand, 2000 N / m or less is preferable. Further, the tension of the adhesive layer is preferably 100 N / m or less and more preferably 10 N / m or less in order to prevent deformation at high temperature.

  Next, (3) a step of laminating the metal foil and the adhesive layer by heating and pressing will be described. It is preferable to heat and press with a pair of rolls, and the material to be laminated can be laminated continuously. The heating temperature is preferably 200 ° C. or higher, more preferably 250 ° C. or higher, from the viewpoint of adhesion between the metal foil and the adhesive layer. On the other hand, in order to prevent oxidation of the metal foil, it is preferably 400 ° C. or lower, and more preferably 370 ° C. or lower. When heating and pressurization is performed in a nitrogen atmosphere, the metal foil can be prevented from being oxidized. Here, the heating temperature refers to the surface temperature of a pressure member such as a roll.

  The nip pressure at the time of heating and pressing is preferably 2 N / cm or more, more preferably 5 N / cm or more, and more preferably 10 N / cm or more. On the other hand, in order to improve dimensional stability, the linear pressure is preferably 150 N / cm or less, more preferably 100 N / cm or less, and more preferably 80 N / cm or less.

  In this step, heat and pressure may be applied via a protective film between the heat and pressure member and the material to be laminated. By using the protective film, more uniform pressurization is possible. Moreover, when a protective film is interposed on the metal foil side, the surface of the metal foil can be prevented. The protective film preferably has heat resistance at 300 ° C. or higher, and the thickness is preferably 20 μm or higher. For example, “Kapton (registered trademark)” 300H, 500H (manufactured by Toray DuPont Co., Ltd.), “Upilex (registered trademark)” 75S, 125S (manufactured by Ube Industries), “Apical (registered trademark)” 75 NPI, 125 NPI (stock) Can be used.

  In the present invention, the time from the preheating step (1) to (3) heating and pressurization is preferably within 20 seconds, and more preferably within 5 seconds. (1) After the preheating step, (3) When there is a time or distance until heating and pressing, the temperature is maintained with an auxiliary heat source so that the material to be laminated is kept within the temperature ± 100 ° C during heating and pressing. It is preferable.

  The manufacturing method of the metal foil laminated film of this invention is demonstrated using FIGS. 9-12. FIG. 9 is a schematic diagram showing an embodiment of a method for producing a single-sided metal foil laminated film of the present invention, FIG. 10 is a schematic diagram showing an embodiment of a method for producing a double-sided metal foil laminated film of the present invention, and FIG. Schematic which shows another aspect of the manufacturing method of a single-sided metal foil laminated film, FIG. 12 is schematic which shows another aspect of the double-sided metal foil laminated film of this invention.

  In FIG. 9, the metal foil 210 and the laminating resin layer 211 are preheated by the laminating roll 204. Here, the lamination resin layer 211 refers to a laminate having an adhesive layer on a heat resistant resin layer. Next, (2) the metal foil and the laminating resin layer are stretched in the TD direction by the cross guider roll 208. A touch roll may be used instead of the cross guider roll. Next, (3) the metal foil 210 and the laminating resin layer 211 are heated and pressed by the laminating roll 204. A protective film 213 is disposed between the laminating roll 204, the metal foil 210, and the laminating resin layer 211, respectively. Next, the protective film 213 is peeled off by the peeling roll 205 to obtain a single-sided metal foil laminated film 212.

  In FIG. 10, (1) the two upper and lower metal foils 210 are preheated by the laminate roll 204, and (2) the metal foil is stretched in the TD direction by the cross guider roll 208. On the laminate roll, a touch roll may be used instead of the cross guider roll. Further, the laminating resin layer 211 is (1) preheated by the preheating heater 207 and (2) stretched in the TD direction by the cross guider roll 208. Next, (3) the metal foil 210 and the laminating resin layer 211 are heated and pressed by the laminating roll 204. A protective film 213 is disposed between the laminating roll 204, the metal foil 210, and the laminating resin layer 211, respectively. Next, the protective film 213 is peeled off by the peeling roll 205 to obtain a double-sided metal foil laminated film 212.

  In FIG. 11, (1) the metal foil 210 and the lamination resin layer 211 are preheated by the preheater 207. Next, (2) the metal foil and the laminating resin layer are stretched in the TD direction by the cross guider roll 208. An expander roll may be used instead of the cross guider roll. Next, (3) the metal foil 210 and the laminating resin layer 211 are heated and pressed by the laminating roll 204. A protective film 213 is disposed between the laminating roll 204, the metal foil 210, and the laminating resin layer 211, respectively. Next, the protective film 213 is peeled off by the peeling roll 205 to obtain a single-sided metal foil laminated film 212.

  In FIG. 12, (1) metal foils 210 are arranged on both surfaces of the laminating resin layer 211, and each is preheated by the preheater 207. Next, (2) the film is stretched in the TD direction by the cross guider roll 208, and (3) heated and pressed by the laminate roll 204 through the protective film 213. Next, the protective film 213 is peeled off by the peeling roll 205 to obtain a double-sided metal foil laminated film 212.

  Next, each layer of the metal foil laminated film will be described.

  Examples of the metal foil include a metal foil for circuit formation and a metal foil for heat dissipation / reflection, but are not particularly limited to these applications. The metal species used in the metal foil for circuit formation may be any metal that can form a circuit with a general etching solution, such as copper, iron, SUS, brass, zinc, tin, and alloys containing these metals. Can be mentioned. In particular, copper is preferably used because it is excellent in etching property and excellent in electrical conductivity and thermal conductivity. When the metal foil and the laminating resin layer are heat-pressed at a high temperature, it is preferable to provide an oxidation rust preventive layer on the surface of the metal foil. Thus, by preventing the oxidation of the surface, the adhesive force between the metal layer and the adhesive layer can be kept high. The method for preventing oxidation may be any method as long as the surface of the metal layer is not oxidized at a high temperature, particularly 200 to 400 ° C., and adhesion with the resin layer for lamination can be ensured. As an example, a method of forming a layer containing a metal such as chromium, zinc, nickel, molybdenum, titanium, vanadium or an oxide thereof on the surface of the metal layer can be given.

  The surface on the adhesive layer side of the metal foil may be roughened. The roughening treatment is effective for improving the adhesive force between the metal foil and the adhesive layer, but the roughness is preferably small for forming a fine circuit. For this reason, the roughness (Rz) of the roughened surface is preferably 4 μm or less, and more preferably 2 μm or less. Considering formation of fine wiring, 1 μm or less is more preferable. In particular, the smooth foil having a roughened surface with an Rz of 0.7 μm or less significantly improves the quality of the metal foil laminated film according to the present invention. Even when the roughened copper foil is in contact with the adhesive layer during thermocompression bonding, only the tips of the surface protrusions are in contact with each other, so that the smoothness is good and wrinkles diverge and are eliminated. However, since smooth copper foil has a large contact area between the resin layer for lamination and the metal foil, friction is large and slipperiness is poor. For this reason, sagging is not eliminated in the thermocompression bonding step, and appearance defects such as wrinkles and wrinkles are easily generated. In the present invention, since the heat sag is removed in advance before the thermocompression bonding, the layers can be laminated without sag. For this reason, lamination by heating and pressurization of a smooth copper foil that could not be realized conventionally has become possible.

  The adhesive layer may be a layer that adheres to the metal foil. The adhesive layer may be formed on a heat resistant resin layer, for example. By using a laminating resin layer having an adhesive layer on the heat resistant resin layer, the heat resistant function and the adhesive function are separated, and the dimensional stability and adhesive performance of the metal foil laminated film are at a high level. Can be maintained.

  Examples of the material constituting the heat resistant resin layer and the adhesive layer include acrylic resins, polyimide resins, polyamide resins, polyamideimide resins, polyetherimide resins, polyethersulfone resins, and polysulfone resins. . Two or more of these may be included. In the present invention, a polyimide resin is preferably used from the viewpoint of heat resistance and insulation reliability.

  Examples of polyimide films preferably used for the heat-resistant resin layer include “Kapton (registered trademark)” manufactured by Toray DuPont Co., Ltd., “Upilex (registered trademark)” manufactured by Ube Industries, Ltd., “Kaneka Co., Ltd.” Apical (registered trademark) ". When used as a flexible printed circuit board (FPC) material, “Kapton” EN type is particularly preferably used from the viewpoint of adhesiveness, dimensional stability, and the like.

  Examples of the polyimide resin preferably used for the adhesive layer include a thermoplastic polyimide resin composition, an organic solvent-soluble polyimide resin composition, a polyimide precursor composition, and the like. For example, by applying a polyimide precursor composition on a heat resistant resin layer and continuously or intermittently heating at a temperature of about 60 to 200 ° C. for 0.5 to 60 minutes to remove the solvent, the adhesive layer is removed. Can be formed.

  In the present invention, the heat-resistant resin layer or the adhesive layer may contain other resins and fillers as long as the effects of the present invention are not impaired. Moreover, each layer, such as a heat resistant resin layer and an adhesive layer, may be subjected to an adhesion improving treatment depending on the purpose. Examples of the adhesion improving treatment include discharge treatment such as atmospheric pressure plasma treatment, corona discharge treatment and low temperature plasma treatment, surface swelling treatment with alkali, desmear treatment with permanganic acid, and primer treatment with a silane coupling agent.

  The film thickness of the adhesive layer or the total film thickness of the laminating resin layer is preferably 5 μm or more, more preferably 10 μm or more, and further preferably 20 μm from the viewpoint of handling properties. Considering the case where it is used for folding resistance and multilayer applications, the thickness is preferably 125 μm or less, more preferably 50 μm or less, and further preferably 40 μm or less.

  EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

First, a polyimide resin for forming an adhesive layer was produced. The names of the abbreviations of acid dianhydride and diamine shown in the following production examples are as follows.
BPDA: 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride SiDA: 1,1,3,3-tetramethyl-1,3-bis (3-aminopropyl) disiloxane DAE: 4,4 '-Diaminodiphenyl ether PDA: p-phenylenediamine NMP: N-methyl-2-pyrrolidone.

  In a reaction kettle equipped with a thermometer, a dry nitrogen inlet, a heating / cooling device using hot water / cooling water, and a stirring device, 62.15 g (0.25 mol) of DDA, 110.11 g (0.55 mol) of DAE, PDA After 21.62 g (0.2 mol) was charged together with 2765 g of NMP and dissolved, 294.2 g (1 mol) of BPDA was added. This was reacted at 70 ° C. for 6 hours to obtain a 15 wt% polyamic acid resin solution (PA1).

  An appearance evaluation method in each example and comparative example will be described.

(1) Wrinkle Evaluation Method A sample of a 500 m (MD) × 500 mm (TD) single-sided metal foil laminated film is cut out and placed on a flat base, visually observed from the laminating resin layer side, and the streaks of the laminating resin layer The presence or absence of undulation due to unevenness was observed. In the double-sided metal foil laminated film, the metal layer on one side was removed by etching and then evaluated in the same manner as the single-sided metal foil laminated film. If waviness due to streak unevenness that did not reach the point by observation occurred, it was judged that wrinkles occurred. A wrinkle having a width of 3 mm or less was regarded as a wrinkle, and a wavy interval of less than 3 mm was considered as a fine wrinkle.

(2) Method for evaluating wrinkle A metal foil laminated film having a width of 500 mm was visually observed and the presence or absence of bending was observed. When the generation | occurrence | production was confirmed after confirming bending generation | occurrence | production per 300 m length of metal foil laminated films, it was set as "Ore generation". In addition, when a 300 m long metal foil laminated film could not be secured due to troubles such as copper foil breakage or raw material exchange, the presence or absence of wrinkles was evaluated per cumulative 300 m length.

(3) Evaluation method of voids A metal foil laminated film having a size of 50 mm square was observed with a stereomicroscope of 200 times from the laminating resin layer side, and the number of bubbles with a major axis of 5 μm or more entering between the copper foil and the film was determined. Calculated as the number of voids. Bubbles were converted into the number per 1 cm ^{2 and} the number of voids. When the number of voids was large, the number of voids was counted in a range including 200 or more voids, and the number of voids was divided by the observed area to obtain the number of voids per unit area.

  The temperature measurement of the metal foil / laminating resin layer was performed by using an infrared thermometer at a measurement point 215 at the center in the TD direction of the substrate between the TD stretching apparatuses, as shown in FIG. When reflection or transmission occurred on a copper foil or film and measurement was not possible, the measurement position was dyed black and the part was measured. The dyed surface was the opposite surface of the heater heating surface. The angle θ of the cross guider roll with respect to the TD direction was 1 ° to 10 °.

In addition, the tension | tensile_strength of the cross guider roll in each Example and a comparative example was measured with the following method. As shown in FIG. 7 or FIG. 8, the traveling position in the width direction was fixed by two sets of rolls separated by a distance L = 1000 [mm] between the laminate roll and the immediately preceding roll in each example and comparative example. A 50 mm “Kapton®” 150EN film was transported at the speed actually used under tension T _MD [N / m]. Next, the parallel movement distance a [mm] of the film when the cross guider roll was used was measured at the midpoint between the two sets of rolls. At this time, the tension T _TD [N / m] of TD stretching by the cross guider roll was determined by the following equation.
T _TD [N / m] = T _MD [N / m] × a [mm] ÷ (L [mm] ÷ 2).

Example 1
The polyamic acid resin solution PA1 is dried on one side of a 25 μm-thick polyimide film (“Kapton” (registered trademark) 100EN manufactured by Toray DuPont Co., Ltd., width 514 mm) that has been subjected to low-temperature plasma treatment in an argon atmosphere in advance. The film was coated with a reverse coater so as to have a film thickness of 2.0 μm, and dried at 80 ° C. for 10 minutes and further at 170 ° C. for 10 minutes to form an adhesive layer to obtain a lamination resin layer. Moreover, NA-DFF foil (Mitsui Metals Mining Co., Ltd. make, thickness 12 micrometers, width 520 mm, lamination | stacking side roughness Rz: 0.5 micrometer) was used as metal foil.

Both the metal foil and the laminating resin layer were sandwiched between a pair of 600 mmφ metal laminate rolls using a touch roll arranged perpendicular to the MD direction, and each was stretched in the TD direction. The tension at that time was 2 N / m for the metal foil and 0.4 N / m for the laminating resin. The roll temperature was 350 ° C., the linear pressure was 50 N / cm, and the speed was 1.0 m / min. The tension in the MD direction of the metal foil was 300 N / m, and the tension in the MD direction of the laminating resin layer was 6 N / m. As a result, the tension ratio R of the metal foil was 0.0067, and the tension ratio R of the resin layer for lamination was 0.067. Both the metal foil and the laminating resin layer were in contact with the laminator roll and stretched in the TD direction for 2 seconds, and further from TD stretch to lamination for 2 seconds. Note that “Kapton” 500H was used as a protective film for the metal roll. It peeled in the back | latter stage and the film with a single side metal was obtained. There were no wrinkles or wrinkles in the product, and the number of voids was reduced to 0.5 / cm ² . No oxidation was observed on the surface of the copper foil after peeling.

(Example 2)
The touch roll angle θ with respect to the TD direction was 4 °. Thus, a product was obtained in the same manner as in Example 1 except that the stretching tension in the TD direction per cross guider roll was 2 N / m for the metal foil and 0.4 N / m for the resin layer for lamination. . The tension ratio R of the copper foil was 0.0067, and the tension ratio R of the resin layer for lamination was 0.067. There were no wrinkles, no wrinkles, and no voids.

(Example 3)
Example 1 with the exception that both the metal foil and the resin layer for lamination were preheated using a non-contact infrastructure heater, immediately followed by stretching in the TD direction with a TD stretching device using a cross guider roll, and heating and pressing with a pair of laminate rolls. Similarly, the film with a single-sided metal was obtained. The tension in the MD direction of the metal foil was 300 N / m, and the tension in the MD direction of the laminating resin layer was 6 N / m. Moreover, the roll angle θ with respect to the TD direction of the cross guider roll was 2 °, and the stretching tension in the TD direction per cross guider roll was 2 N / m for the metal foil and 0.4 N / m for the resin layer for lamination. . As a result, the tension ratio R of the metal foil was 0.0067, and the tension ratio R of the resin layer for lamination was 0.067. The temperature of both the copper foil and the laminating resin layer on the path from the preheated part to the thermocompression bonding is between 250 ° C. and 350 ° C., and the temperature of the metal foil and laminating resin layer at the measurement point is 300 ° C. It was. The product was free of wrinkles, wrinkles and voids. No oxidation was observed on the surface of the copper foil after peeling.

Example 4
A product was obtained in the same manner as in Example 3 except that the pre-heating of the laminating resin layer and TD stretching were not performed. The copper foil temperature at the measurement point was 300 ° C. There were no wrinkles, no wrinkles, and no voids.

(Example 5)
A product was obtained in the same manner as in Example 3 except that the metal foil was not preheated and TD stretched. The temperature of the resin layer for lamination at the measurement point was 300 ° C. I didn't have any wrinkles. Voids were generated at a frequency of 50 / cm ² .

(Example 6)
The product was obtained in the same manner as in Example 3 except that the output of the infrastructure heater was adjusted and the temperature of the metal foil / laminating resin layer at the measurement point was both 270 ° C. Neither wrinkles nor wrinkles were generated, and the number of voids was reduced to 0.5 / cm ² .

(Example 7)
The product was obtained in the same manner as in Example 3 except that the output of the infrastructure heater was adjusted and the temperature of the metal foil / laminating resin layer at the measurement point was 230 ° C. I did not occur, but loose wrinkles occurred. Voids were generated at a frequency of 10 / cm ² .

(Example 8)
A product was obtained in the same manner as in Example 3 except that the tension in the MD direction of the metal foil was adjusted to 600 N / m. The tension ratio of the copper foil was 0.0033. Neither wrinkles nor wrinkles occurred, and no voids occurred.

Example 9
The tension in the MD direction of the metal foil was adjusted to 600 N / m, and the angle θ of the cross guider roll was set to 4 °. Thus, a product was obtained in the same manner as in Example 3 except that the cross guider roll had a TD direction tension of 4 N / m. The tension ratio of the metal foil was 0.0067. Neither wrinkles nor wrinkles occurred, and no voids occurred.

(Example 10)
The tension in the MD direction of the metal foil was adjusted to 600 N / m, and the angle θ of the cross guider roll was set to 1 °. Thus, a product was obtained in the same manner as in Example 3 except that the cross guider roll had a TD direction tension of 0.6 N / m. The tension ratio of the metal foil was 0.001. Although wrinkles did not occur, wrinkles stopped, and voids occurred at a frequency of 50 / cm ² .

(Example 11)
A product was obtained in the same manner as in Example 10 except that V2-DFF (Mitsui Metal Mining Co., Ltd., thickness 12 μm, width 520 mm, lamination-side roughness Rz: 2 μm) was used for the metal foil. There were no wrinkles or wrinkles, and no voids.

(Comparative Example 1)
A product was obtained in the same manner as in Example 3 except that the preheating step and the TD stretching step were not performed. Both wrinkles and wrinkles occurred on the entire surface, and voids were generated at 1000 / cm ² .

(Comparative Example 2)
A product was obtained in the same manner as in Example 3 except that the TD stretching step was not performed on the metal foil and the resin layer for lamination. Although I did not occur, many wrinkles occurred. 100 voids / cm ^{2 were} generated.

(Comparative Example 3)
A product was obtained in the same manner as in Example 3 except that the preheating step was not performed on the metal foil and the resin layer for lamination. Both wrinkles and wrinkles occurred, and 800 voids / cm ^{2 were} generated.

  The results of Examples 1 to 11 and Comparative Examples 1 to 3 are shown in Table 1.

  The metal foil laminated film obtained by the production method of the present invention is particularly suitable for a flexible circuit board material for electronic devices such as mobile phones, displays, and digital cameras.

Schematic which shows one aspect | mode of the structure of the metal foil laminated film obtained by this invention Schematic which shows another aspect of the structure of the metal foil laminated film obtained by this invention Schematic which shows another aspect of the structure of the metal foil laminated film obtained by this invention Schematic which shows the one aspect | mode of the process of preheating and TD extending | stretching of the metal foil laminated film of this invention Schematic which shows the one aspect | mode of the process of extending | stretching a to-be-laminated material in a TD direction using a cross guider roll on a heating-pressing member. Schematic which shows another aspect of the process of extending | stretching a to-be-laminated material on a heating-pressing member in a TD direction using a touch roll. Schematic which shows the one aspect | mode of the measuring method of the tension | tensile_strength of the TD direction in this invention. Schematic which shows another aspect of the measuring method of the tension | tensile_strength of the TD direction in this invention. Schematic which shows the one aspect | mode of the manufacturing method of the single-sided metal foil laminated film of this invention. Schematic which shows one aspect | mode of the manufacturing method of the double-sided metal foil laminated film of this invention. Schematic which shows another aspect of the manufacturing method of the single-sided metal foil laminated film of this invention. Schematic which shows another aspect of the manufacturing method of the double-sided metal foil laminated film of this invention.

Explanation of symbols

101: Metal layer 102: Adhesive layer 103: Heat resistant resin layer 201: Metal foil unwinding shaft (upper)
202: Metal foil unwinding shaft (bottom)
203: Laminating resin layer unwinding shaft 204: Laminating roll 205: Peeling roll 206: Winding shaft 207: Preheating heater 208: Cross guider roll, expander roll or touch roll 209: Protective film unwinding shaft
210: Metal foil 211: Laminating resin layer 212: Metal foil laminated film 213: Protective film 214: SUS plate 215: Measuring point L: Distance between rolls a: Parallel movement distance _TMD : Tension in MD direction _TTD : TD direction Tension t ₀ : heating and pressurizing temperature t _p : preheating temperature (temperature at the measurement point during TD stretching)
t: Difference between heating and pressing temperature and preheating temperature θ: Angle of cross guider roll with respect to TD direction (1): Preheating step (2): TD stretching step (3): Heating and pressing step (4): Laminate roll contact start position

Claims (5)

A method for producing a metal foil laminated film in which at least a metal foil and an adhesive layer are laminated by heating and pressing,
(1) Step of preheating metal foil or adhesive layer (2) Step of stretching preheated metal foil or adhesive layer in TD direction (3) Step of laminating metal foil and adhesive layer by heating and pressing in this order method for producing a metal foil laminated film, which comprises carrying out in. 2. The method for producing a metal foil laminated film according to claim 1, wherein the temperature of the metal foil or the adhesive layer in the step (2) is within the heating temperature ± 100 ° C. in the step (3). In the step (1), the metal foil or the adhesive layer is preheated by a heating and pressing member, and in the step (2), the metal foil or the adhesive layer is stretched in the TD direction on the heating and pressing member. The manufacturing method of the metal foil laminated film of Claim 1 or 2. The method for producing a metal foil laminated film according to any one of claims 1 to 3, wherein in the step (2), both ends of the metal foil or the adhesive layer are held and stretched in the TD direction. In the step (2), the ratio between the tension in the TD direction and the tension in the MD direction of the metal foil or adhesive layer stretched in the TD direction (tension in the TD direction [N / m] / tension in the MD direction [N / M]) is 0.0012 or more and 0.1 or less, The manufacturing method of the metal foil laminated film in any one of Claims 1-4 characterized by the above-mentioned.

Images