JP2013051323A - Powder molding device and process of producing powder molding sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a powder molding sheet having good appearance in which the accuracy of film thickness is enhanced.SOLUTION: The powder molding device comprises a pair of rolls 4A, 4B having the axes of rotation in parallel with each other and rotating in opposite direction to each other, a powder reservoir section in which the powder being supplied between the pair of rolls is stored, and a backing material conveyance section which passes a backing material 16 between the pair of rolls so as to embrace one of the pair of rolls. In a state where the pressure from the pair of rolls is less likely to be applied to both ends of the backing material in the width direction, the powder supplied from the powder reservoir section is formed on the backing material by rolling.

Description

  The present invention relates to a powder forming apparatus for rolling and forming powder between rolls and a method for producing a powder formed sheet using this apparatus.

  The demand for electrochemical devices such as lithium ion secondary batteries and electric double layer capacitors that are small and light, have high energy density, and can be repeatedly charged and discharged is expected to increase in the future from the environmental viewpoint. Lithium-ion rechargeable batteries have high energy density and are used in the fields of mobile phones and laptop computers. Electric double layer capacitors are capable of rapid charge and discharge and are used as memory backup compact power sources for personal computers. Yes. In addition, lithium ion capacitors that utilize the oxidation-reduction reaction (pseudo electric double layer capacity) on the surface of metal oxides or conductive polymers are also attracting attention because of their large capacity. With the expansion and development of applications, these electrochemical devices are required to have further improved performance by reducing resistance, increasing capacity, improving mechanical properties, and the like. In order to improve the performance of the electrochemical element, various improvements have been made to the method for producing the electrochemical element, the electrolyte, and the electrolytic solution.

  As one of the powder rolling techniques which are methods for producing electrode chemical elements, a roll heating direct powder rolling method has been conventionally known. In the powder rolling apparatus for carrying out such a powder rolling method, a pair of rolling rolls are arranged horizontally and in parallel, a base material is provided between the rolling rolls, and a partition plate provided at an upper portion between the rolling rolls. The sheet charged with the powder is drawn into the gap between the rolling rolls by rotating the rolling roll to produce a sheet on which the powder is continuously formed (for example, see Patent Documents 1 to 3).

JP 2006-303395 A JP 2006-339184 A JP 2007-5747 A

  However, when producing a laminated sheet consisting of a base material and a powder layer by rolling the powder, a trace remains as if pressure is applied to the end of the base material after passing between the rolls. In some cases, the base material was discolored or wrinkled, resulting in a defective product. Moreover, the thickness of the laminated sheet edge part near a partition plate became thick compared with the laminated sheet center part by the influence of a partition plate, and the film thickness of a laminated sheet may produce variation. Further, when the powder stored in the partition plate is supplied between the rolls, powder leakage may occur from the end of the roll, which may deteriorate the yield of the powder.

  An object of the present invention is to provide a powder molding apparatus for molding a powder molded sheet having a good appearance and improved film thickness accuracy, and a method for producing a powder molded sheet using the apparatus.

  As a result of studying to achieve the above object, the present inventor obtained a powder molded sheet with good appearance and improved film thickness accuracy by making it difficult to apply pressure to the end of the substrate. I found out that The present invention has been completed based on these findings.

According to the present invention,
(1) A pair of rolls whose rotation axes are parallel and rotate in opposite directions, a powder storage part storing powder supplied between the pair of rolls, and one of the pair of rolls And a base material transport section for transporting the base material between the pair of rolls so that the pressure from the pair of rolls is not easily applied to both ends in the width direction of the base material. A powder forming apparatus, wherein the powder supplied from the body storage unit is roll-formed on the base material,
(2) The powder molding apparatus according to (1), further comprising a film placed on the surface of both end portions of the base material,
(3) The powder molding apparatus according to (2), wherein the film has a thickness of 10 μm to 500 μm,
(4) It further includes a pair of partition plates installed at both ends of a recess formed above the pair of rolls, so that the film contacts the base material or the roll and does not contact the partition plates. The powder molding apparatus according to (2) or (3), wherein the powder molding apparatus is arranged,
(5) The powder molding apparatus according to any one of (2) to (4), wherein the film is disposed so as to pass through a gap between the roll and the partition plate.
(6) The powder molding apparatus according to any one of (2) to (5), wherein the film is capable of changing the position in the width direction of the base material in accordance with the width of the base material. ,
(7) The axial length of the other roll of the pair of rolls is made shorter than the axial length of the one roll so as not to face both ends of the substrate. (1) The powder molding apparatus according to (1),
(8) The powder molding apparatus according to (1), wherein grooves are provided at both ends of the other roll of the pair of rolls,
(9) The powder molding apparatus according to (1), characterized in that the axial length of the pair of rolls is substantially equal to the width of the powder to be roll-formed on the substrate.
(10) The powder molding apparatus according to (1), wherein non-rotating sleeves are provided at both ends of the other of the pair of rolls.
(11) The axial length of the other roll of the pair of rolls is made shorter than the axial length of the one roll, and the other roll is stopped or stopped at both ends. The powder forming apparatus according to (1), wherein an end roll that rotates in a direction opposite to the roll is provided,
(12) Using the powder molding apparatus according to any one of (1) to (11), the powder supplied from the powder storage unit is roll-formed with the pair of rolls and powdered on the base material. A method for producing a powder molded sheet for laminating body layers,
Is provided.

  According to the present invention, it is possible to produce a powder molded sheet having a good appearance and improved film thickness accuracy.

It is the schematic which looked at the powder molding apparatus which concerns on 1st Embodiment from the side. It is the schematic diagram which looked at the powder forming apparatus concerning a 1st embodiment from the upper part. It is the schematic which looked at the powder shaping | molding apparatus which concerns on 2nd Embodiment from the side. It is the schematic diagram which looked at the powder molding apparatus concerning a 2nd embodiment from the upper part. It is the schematic which looked at the powder molding apparatus which concerns on 3rd Embodiment from the side. It is the schematic diagram which looked at the powder molding apparatus which concerns on 3rd Embodiment from the upper part. It is the schematic which looked at the powder shaping | molding apparatus which concerns on 4th Embodiment from the side. It is the schematic diagram which looked at the powder molding apparatus which concerns on 4th Embodiment from the upper part. It is the schematic which looked at the powder shaping | molding apparatus which concerns on 5th Embodiment from the side. It is the schematic diagram which looked at the powder forming apparatus which concerns on 5th Embodiment from the upper part. It is the schematic which looked at the powder molding apparatus which concerns on 6th Embodiment from the side. It is the schematic diagram which looked at the powder forming apparatus concerning a 6th embodiment from the upper part.

  Hereinafter, a powder molding apparatus and a method for manufacturing a powder molded sheet according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic view of the powder molding apparatus according to the first embodiment as viewed from the side, and FIG. 2 is a schematic view of the powder molding apparatus according to the first embodiment as viewed from above. As shown in FIG. 1, the partition plates 8A and 8B have a width from the uppermost part of the roll 4A to the uppermost part of the roll 4B. However, in order to facilitate understanding of the configuration of the powder molding apparatus 2. In FIG. 2, the partition plates 8A and 8B are shown only at the roll nip point (the portion where the roll gap between the rolls 4A and 4B is the narrowest).

  The powder molding apparatus 2 includes a compression roll 4 including a pair of rolls 4A and 4B whose rotational axes are arranged horizontally and in parallel and rotate downward in the proximity portion. A pair of partition plates 8A and 8B are disposed at both ends of the recess formed in the upper part between the pair of rolls 4A and 4B, and a space formed by the pair of rolls 4A and 4B and the pair of partition plates 8A and 8B. The powder 6 is stored.

  Further, a pair of ribbon-like films 12 attached between film stoppers 10 disposed above and below the compression roll 4 are provided so as to extend from the top to the bottom of the compression roll 4 through the gap between the rolls 4A and 4B. Yes. Here, the pair of ribbon-like films 12 are respectively disposed at both ends of the pair of rolls 4A and 4B, and are attached so as to touch the base material 16 or the roll 4A but not the partition plates 8A and 8B. Furthermore, the ribbon-like film 12 is attached so as to pass through a gap between the roll 4A and the partition plates 8A and 8B. The ribbon-like film 12 is appropriately selected to have a thickness of 10 μm to 500 μm based on the thickness of the powder molded sheet to be produced. Thereby, it can prevent that the ribbon-like film 12 is wound in the compression roll 4 in the case of rolling, and the ribbon-like film 12 cuts.

  Further, the position of the ribbon-shaped film 12 with respect to the rolls 4 </ b> A and 4 </ b> B can be changed in the width direction of the base material 16 in accordance with the width of the base material 16. Here, the base material 16 unwound from the base material unwinding roll 14 passes the guide roll 18, holds the roll 4 </ b> A, passes between the roll 4 </ b> A and the roll 4 </ b> B, passes through another guide roll 20, It is set so as to be wound around the substrate winding roll 22. That is, the base material 16 is set between the rolls 4A and 4B and the ribbon film 12 at both ends of the rolls 4A and 4B.

  The rolls 4A and 4B of the compression roll 4 are rotated in the direction of the arrow shown in FIG. 1 to bite the powder 6, and the powder 6 is rolled and formed on one surface of the substrate 16 by the rolls 4A and 4B. FIG. 2 shows a case where the powder 6 is rolled and formed on one surface of the substrate 16 and the powder layer 7 is formed, and then the powder 6 is rolled and formed on the other surface again. Here, the rolls 4A and 4B of the compression roll 4 rotate by being driven by a motor or the like, but the rotation speeds of the rolls 4A and 4B can be freely changed. The compression roll 4 is provided with a temperature adjustment mechanism capable of adjusting the temperature such as cooling and heating according to the kind and properties of the powder. Examples of the temperature adjusting mechanism include a method of using a heat medium disposed inside the rolls 4A and 4B, a method of heating with a direct heat transfer wire, and the like.

  In the powder forming apparatus according to this embodiment, since the ribbon-like film 12 is placed on the upper surface of both ends of the base material 16, this portion is also used when the rolls 4A and 4B rotate. Since the gap between the rolls 4A and 4B (roll interval) is small in this portion, the portion where the ribbon-like film 12 is twisted even when the rolls 4A and 4B are rotated It is difficult to apply pressure to the base material 16 without biting the body 6. Accordingly, generation of wrinkles at both ends of the base material 16 and discoloration of the base material 16 can be prevented. In addition, since both ends of the rolled powder and the partition plates 8A and 8B are not close to each other and are not directly affected by the partition plates 8A and 8B, the thickness of the powder molded sheet (powder layer 7) is uniform. Can be. For this reason, it is not necessary to separately provide a step of cutting defective portions of the powder molded sheet after rolling, which contributes to prevention of yield deterioration and improvement of production efficiency. Further, the powder 6 stays on the ribbon-like film 12 to reduce powder leakage, and even when the powder 6 leaks, the powder 6 can be collected and reused as it is. Reduction can be achieved.

  Next, a powder molding apparatus and a method for producing a powder molded sheet according to the second embodiment of the present invention will be described. FIG. 3 is a schematic view of the powder molding apparatus according to the second embodiment as viewed from the side, and FIG. 4 is a schematic view of the powder molding apparatus according to the second embodiment as viewed from above. As shown in FIG. 3, the partition plates 8A and 8B have a width from the uppermost part of the roll 4A to the uppermost part of the roll 4B. However, in order to make the configuration of the powder forming apparatus 200 easier to understand. 4 shows the partition plates 8A and 8B only for the roll nip point. The configuration of the powder molding apparatus 200 according to the second embodiment is such that the pair of ribbon-like films 12 of the powder molding apparatus 2 according to the first embodiment shown in FIG. , 4B, the length of the roll 4B in the axial direction is made shorter than the length of the roll 4A in the axial direction so as not to face both ends of the substrate 16. Therefore, a detailed description of the same configuration as that of the first embodiment is omitted, and the same configuration as that of the first embodiment is denoted by the same reference numeral.

  The rolls 4A and 4B of the compression roll 4 of the powder forming apparatus 200 bite the powder 6 by rotating in the direction of the arrow shown in FIG. 3, respectively, and the powder 6 is fed to one surface of the base 16 by the rolls 4A and 4B. Rolled into FIG. 4 shows a case where the powder 6 is rolled and formed on one surface of the substrate 16 and the powder layer 7 is formed, and then the powder 6 is rolled and formed on the other surface again.

  In the powder forming apparatus 200 according to this embodiment, the axial length of the roll 4B of the pair of rolls 4A and 4B is made shorter than the axial length of the roll 4A, and the base material 16 Therefore, the pressure from the rolls 4A and 4B is not applied to this portion. Therefore, generation | occurrence | production of the wrinkles in the both ends of the base material 16 and the discoloration of the base material 16 can be prevented, and the thickness of a powder-molded sheet can be made uniform. For this reason, it is not necessary to separately provide a step of cutting defective portions of the powder molded sheet after rolling, which contributes to prevention of yield deterioration and improvement of production efficiency.

  Next, a powder molding apparatus and a method for manufacturing a powder molded sheet according to the third embodiment of the present invention will be described. FIG. 5 is a schematic view of the powder molding apparatus according to the third embodiment as viewed from the side, and FIG. 6 is a schematic view of the powder molding apparatus according to the third embodiment as viewed from above. As shown in FIG. 5, the partition plates 8A and 8B have a width from the uppermost part of the roll 4A to the uppermost part of the roll 4B, but in order to make it easy to understand the configuration of the powder forming apparatus 202. 6 shows the partition plates 8A and 8B only for the roll nip point. The configuration of the powder molding apparatus 202 according to the third embodiment is such that the pair of ribbon-like films 12 of the powder molding apparatus 2 according to the first embodiment shown in FIG. , 4B, the groove 5 is formed at the axial end of the roll 4B. Therefore, a detailed description of the same configuration as that of the first embodiment is omitted, and the same configuration as that of the first embodiment is denoted by the same reference numeral.

  The rolls 4A and 4B of the compression roll 4 of the powder forming apparatus 202 bite the powder 6 by rotating in the direction of the arrow shown in FIG. 5, respectively, and the powder 6 is fed to one surface of the base 16 by the rolls 4A and 4B. Rolled into FIG. 6 shows a case where the powder 6 is rolled and formed on one surface of the substrate 16 and the powder layer 7 is formed, and then the powder 6 is rolled and formed on the other surface again.

  In the powder molding apparatus 202 according to this embodiment, since the groove 5 is formed at the end portion in the axial direction of the roll 4B, even when the rolls 4A and 4B rotate in this portion, the base material 16 is provided. No pressure is applied and the powder 6 is not rolled. Therefore, generation | occurrence | production of the wrinkles in the both ends of the base material 16 and the discoloration of the base material 16 can be prevented, and the thickness of a powder-molded sheet can be made uniform. For this reason, it is not necessary to separately provide a step of cutting defective portions of the powder molded sheet after rolling, which contributes to prevention of yield deterioration and improvement of production efficiency.

  Next, a powder molding apparatus and a method for producing a powder molded sheet according to the fourth embodiment of the present invention will be described. FIG. 7 is a schematic view of the powder molding apparatus according to the fourth embodiment as viewed from the side, and FIG. 8 is a schematic view of the powder molding apparatus according to the fourth embodiment as viewed from above. As shown in FIG. 7, the partition plates 8A and 8B have a width from the uppermost part of the roll 4A to the uppermost part of the roll 4B. However, in order to make the configuration of the powder forming apparatus 204 easier to understand. 8 shows the partition plates 8A and 8B only for the roll nip point. The configuration of the powder molding apparatus 204 according to the fourth embodiment is the length of the pair of rolls 4A and 4B in the powder molding apparatus 2 according to the first embodiment shown in FIG. The width of the powder 6 to be roll-formed on the base material 16 is made substantially equal, and both end portions of the base material 16 are exposed to the outside of the rolls 4A and 4B. Therefore, a detailed description of the same configuration as that of the first embodiment is omitted, and the same configuration as that of the first embodiment is denoted by the same reference numeral.

  The rolls 4A and 4B of the compression roll 4 of the powder forming apparatus 204 bite the powder 6 by rotating in the direction of the arrow shown in FIG. 7, respectively, and the powder 6 is fed to one surface of the substrate 16 by the rolls 4A and 4B. Rolled into FIG. 8 shows a case where the powder 6 is rolled and formed on one surface of the substrate 16 and the powder layer 7 is formed, and then the powder 6 is rolled and formed on the other surface again.

  In the powder forming apparatus 204 according to this embodiment, the length in the axial direction of the pair of rolls 4A and 4B is made substantially equal to the width of the powder 6 roll-formed on the base material 16, and both end portions of the base material 16 are set. Is exposed to the outside of the rolls 4A and 4B, the pressure from the rolls 4A and 4B is not applied to both ends of the base material 16. Therefore, generation | occurrence | production of the wrinkles in the both ends of the base material 16 and the discoloration of the base material 16 can be prevented, and the thickness of a powder-molded sheet can be made uniform. For this reason, it is not necessary to separately provide a step of cutting defective portions of the powder molded sheet after rolling, which contributes to prevention of yield deterioration and improvement of production efficiency.

  Next, a powder molding apparatus and a method for producing a powder molded sheet according to the fifth embodiment of the present invention will be described. FIG. 9 is a schematic view of the powder molding apparatus according to the fifth embodiment as viewed from the side, and FIG. 10 is a schematic view of the powder molding apparatus according to the fifth embodiment as viewed from above. As shown in FIG. 9, the partition plates 8A and 8B have a width from the uppermost part of the roll 4A to the uppermost part of the roll 4B. However, in order to facilitate understanding of the configuration of the powder forming apparatus 206. 10 shows the partition plates 8A and 8B only for the roll nip point. The configuration of the powder molding apparatus 206 according to the fifth embodiment is the same as that of both ends of the roll 4B in the pair of rolls 4A and 4B of the powder molding apparatus 2 according to the first embodiment shown in FIG. A step portion having a small diameter is provided in the portion, and a sleeve 9 that does not rotate is attached to the step portion. Therefore, a detailed description of the same configuration as that of the first embodiment is omitted, and the same configuration as that of the first embodiment is denoted by the same reference numeral.

  The rolls 4A and 4B of the compression roll 4 of the powder forming apparatus 206 bite the powder 6 by rotating in the direction of the arrow shown in FIG. 9, and the powder 6 is fed to one surface of the substrate 16 by the rolls 4A and 4B. Rolled into FIG. 10 shows a case where the powder 6 is rolled and formed on one surface of the substrate 16 and the powder layer 7 is formed, and then the powder 6 is rolled and formed on the other surface again.

  In the powder forming apparatus 206 according to this embodiment, a step portion having a small diameter is provided at both ends of the roll 4B of the pair of rotating rolls 4A and 4B, and a sleeve 9 that does not rotate is attached to the step portion. Therefore, since the powder 6 is not bitten in this portion, the pressure from the rolls 4A and 4B is not applied to the base material 16. Therefore, generation | occurrence | production of the wrinkles in the both ends of the base material 16 and the discoloration of the base material 16 can be prevented, and the thickness of a powder-molded sheet can be made uniform. For this reason, it is not necessary to separately provide a step of cutting defective portions of the powder molded sheet after rolling, which contributes to prevention of yield deterioration and improvement of production efficiency. The powder 6 that has entered the sleeve 9 of the roll 4B can be recovered and reused as it is.

  Next, a powder molding apparatus and a method for producing a powder molded sheet according to the sixth embodiment of the present invention will be described. FIG. 11 is a schematic view of the powder molding apparatus according to the sixth embodiment as viewed from the side, and FIG. 12 is a schematic view of the powder molding apparatus according to the sixth embodiment as viewed from above. As shown in FIG. 11, the partition plates 8A and 8B have a width from the uppermost part of the roll 4A to the uppermost part of the roll 4B. However, in order to make the configuration of the powder forming apparatus 208 easier to understand. In FIG. 12, the partition plates 8A and 8B are shown only for the roll nip point. The configuration of the powder forming apparatus 208 according to the sixth embodiment is such that the axial length of the roll 4B in the pair of rolls 4A and 4B shown in FIG. 2 is changed to the axial length of the roll 4A. In comparison, the length is shortened, and both ends are provided with end rolls 11 that are separately driven, so that no pressure is applied to both ends of the base material 16. Therefore, a detailed description of the same configuration as that of the first embodiment is omitted, and the same configuration as that of the first embodiment is denoted by the same reference numeral.

  The rolls 4A and 4B of the compression roll 4 of the powder forming apparatus 208 bite the powder 6 by rotating in the direction of the arrow shown in FIG. 11, respectively, and the powder 6 is fed to one surface of the base 16 by the rolls 4A and 4B. Rolled into FIG. 12 shows a case where the powder 6 is rolled and formed on one surface of the substrate 16 and the powder layer 7 is formed, and then the powder 6 is rolled and formed on the other surface again.

  In the powder forming apparatus 208 according to this embodiment, the length of the roll 4B in the pair of rolls 4A and 4B is made shorter than the length of the roll 4A in the axial direction, at both ends. In the part which the roll 11 of the base material 16 opposes by providing the end roll 11 by another drive, and stopping the end roll 11 or rotating the end roll 11 in the opposite direction to the roll 4B. Since the body 6 is not bitten, the pressure from the roll 4A and the roll 11 is not applied to the base material 16. Therefore, generation | occurrence | production of the wrinkles in the both ends of the base material 16 and the discoloration of the base material 16 can be prevented, and the thickness of a powder-molded sheet can be made uniform. For this reason, it is not necessary to separately provide a step of cutting defective portions of the powder molded sheet after rolling, which contributes to prevention of yield deterioration and improvement of production efficiency. Moreover, although the part of the end roll 11 has a structure in which the powder 6 is difficult to enter, even when it enters the end roll 11 part, the powder 6 can be recovered and reused as it is.

  The substrate 16 used in the present invention may be a thin film substrate, and usually has a thickness of 1 μm to 1000 μm, preferably 5 μm to 800 μm. Examples of the substrate 16 include metal foils such as aluminum, copper, stainless steel, and iron, paper, natural fibers, polymer fibers, fabrics, polymer resin films, and the like, which can be appropriately selected according to the purpose. Examples of the polymer resin film include polyester resin films such as polyethylene terephthalate and polyethylene naphthalate, plastic films and sheets including polyimide, polypropylene, polyphenylene sulfide, polyvinyl chloride, aramid film, PEN, PEEK, and the like. It is done.

  Further, the surface of the base material 16 may be subjected to treatment such as coating treatment, drilling, buffing, sandblasting and / or etching. A substrate obtained by applying an adhesive or the like to the backup substrate surface is particularly preferable because it can hold the sheet-like powder firmly.

  Examples of the material of the ribbon-like film 12 used in the present invention include resin films such as polyethylene terephthalate, polyethylene naphthalate, polyester, polyimide, polypropylene, and polycarbonate, and metal foils such as aluminum and copper.

  Examples of the powder 6 stored in the space formed by the rolls 4A and 4B and the partition plates 8A and 8B include composite particles including an electrode active material.

  The composite particles include an electrode active material and a binder, and may include other dispersants, conductive materials, and additives as necessary.

  When the composite particles are used as an electrode material for a lithium ion secondary battery, examples of the positive electrode active material include metal oxides capable of reversibly doping and dedoping lithium ions. Examples of such metal oxides include lithium cobaltate, lithium nickelate, lithium manganate, lithium iron phosphate, lithium manganese phosphate, lithium vanadium phosphate, lithium iron vanadate, nickel-manganese-lithium cobaltate, nickel-cobalt acid. Lithium, nickel-lithium manganate, iron-lithium manganate, iron-manganese-lithium cobaltate, lithium iron silicate, iron silicate-lithium manganese oxide, vanadium oxide, copper vanadate, niobium oxide, titanium sulfide, molybdenum oxide, molybdenum sulfide , Etc. In addition, the positive electrode active material illustrated above may be used independently according to a use, and may be used in mixture of multiple types.

  Furthermore, polymers such as polyacetylene, poly-p-phenylene and polyquinone can be mentioned. Of these, it is preferable to use a lithium-containing metal oxide.

  In addition, as an active material of the negative electrode as a counter electrode of the positive electrode for the lithium ion secondary battery, low crystalline carbon (amorphous carbon) such as graphitizable carbon, non-graphitizable carbon, activated carbon, pyrolytic carbon, Graphite (natural graphite, artificial graphite), carbon nanowalls, carbon nanotubes, or composite carbon materials of carbon having different physical properties, alloy materials such as tin and silicon, silicon oxide, tin oxide, vanadium oxide And oxides such as lithium titanate, polyacene, and the like. In addition, the electrode active material illustrated above may be used independently according to a use, and may be used in mixture of multiple types.

  The shape of the electrode active material for a lithium ion secondary battery electrode is preferably a granulated particle. When the shape of the particles is spherical, a higher density electrode can be formed during electrode molding.

  The volume average particle diameter of the electrode active material for a lithium ion secondary battery electrode is usually 0.1 to 100 μm, preferably 0.5 to 50 μm, more preferably 0.8 to 20 μm for both the positive electrode and the negative electrode.

The tap density of the electrode active material for a lithium ion secondary battery is not particularly limited, but a material having a positive electrode of 2 g / cm ³ or more and a negative electrode of 0.6 g / cm ³ or more is preferably used.

  When composite particles are used as electrode materials for lithium ion capacitors, active materials for positive electrodes include activated carbon, polyacene organic semiconductor (PAS), carbon nanotubes, carbon whiskers that can be reversibly doped and dedoped with anions and / or cations. And graphite. Preferred electrode active materials are activated carbon and carbon nanotubes.

  In addition, as the negative electrode active material as the counter electrode of the positive electrode for a lithium ion capacitor, any of the materials exemplified as the negative electrode active material for a lithium ion secondary battery can be used. The volume average particle diameter of the electrode active material used for the electrode for a lithium ion capacitor is usually 0.1 to 100 μm, preferably 0.5 to 50 μm, and more preferably 0.8 to 20 μm.

When using activated carbon as the lithium ion capacitor electrode active material, the specific surface area of activated carbon, ^{30 m} 2 / g or more, preferably 500~3,000m ² / g, more preferably 1,500~2,600m ² / g . The capacitance per unit weight of activated carbon tends to increase as the specific surface area increases up to about 2,000 m ² / g, but thereafter the capacitance does not increase so much. The density of the material layer tends to decrease, and the capacitance density tends to decrease. Moreover, it is preferable in terms of rapid charge / discharge characteristics, which is a feature of a lithium ion capacitor, that the pore size of the activated carbon is compatible with the size of the electrolyte ion. Therefore, an electrode mixture layer having desired capacity density and input / output characteristics can be obtained by appropriately selecting an electrode active material.

  When the composite particles are used as an electrode material for an electric double layer capacitor, any of the materials exemplified as the positive electrode active material for a lithium ion capacitor can be used as the positive electrode active material and the negative electrode active material.

  The binder used for the composite particles is not particularly limited as long as it is a compound capable of binding the electrode active materials to each other. A suitable binder is a dispersion type binder having a property of being dispersed in a solvent. Examples of the dispersion-type binder include high molecular compounds such as silicon polymers, fluorine-containing polymers, conjugated diene polymers, acrylate polymers, polyimides, polyamides, polyurethanes, and preferably fluorine-containing polymers. Polymers, conjugated diene polymers and acrylate polymers, more preferably conjugated diene polymers and acrylate polymers.

  The diene polymer is a homopolymer of a conjugated diene or a copolymer obtained by polymerizing a monomer mixture containing a conjugated diene, or a hydrogenated product thereof. The proportion of the conjugated diene in the monomer mixture is usually 40% by weight or more, preferably 50% by weight or more, more preferably 60% by weight or more. Specific examples of the diene polymer include conjugated diene homopolymers such as polybutadiene and polyisoprene; aromatic vinyl / conjugated diene copolymers such as carboxy-modified styrene / butadiene copolymer (SBR); acrylonitrile -Vinyl cyanide * conjugated diene copolymers, such as a butadiene copolymer (NBR); Hydrogenated SBR, hydrogenated NBR, etc. are mentioned.

The acrylate polymer is represented by the general formula (1): CH ₂ = CR ¹ —COOR ² (wherein R ¹ represents a hydrogen atom or a methyl group, and R ² represents an alkyl group or a cycloalkyl group). Polymer containing monomer unit derived from compound, specifically, homopolymer of compound represented by general formula (1), or monomer mixture containing compound represented by general formula (1) Is a copolymer obtained by polymerizing Specific examples of the compound represented by the general formula (1) include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, and (meth) acrylate n. -Butyl, isobutyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isopentyl (meth) acrylate, isooctyl (meth) acrylate, isobornyl (meth) acrylate, (meth) (Meth) acrylic acid alkyl esters such as isodecyl acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, and tridecyl (meth) acrylate; butoxyethyl (meth) acrylate, ethoxydiethylene glycol (meth) acrylate , (Meth) acrylic acid methoxydipropylene Recall, (meth) acrylic acid methoxypolyethylene glycol, (meth) acrylic acid phenoxyethyl, (meth) acrylic acid tetrahydrofurfuryl ether group-containing (meth) acrylic acid ester; (meth) acrylic acid-2-hydroxyethyl, Hydroxyl-containing (meth) acrylic such as (meth) acrylic acid-2-hydroxypropyl, (meth) acrylic acid-2-hydroxy-3-phenoxypropyl, 2- (meth) acryloyloxyethyl-2-hydroxyethylphthalic acid Acid ester; 2- (meth) acryloyloxyethylphthalic acid, carboxylic acid-containing (meth) acrylic acid ester such as 2- (meth) acryloyloxyethylphthalic acid; Fluorine such as perfluorooctylethyl (meth) acrylate Group-containing (meth) acrylic acid ester; Phosphoric acid group-containing (meth) acrylic acid esters such as ethyl phosphate; Epoxy group-containing (meth) acrylic acid esters such as glycidyl (meth) acrylate; Amino group content such as dimethylaminoethyl (meth) acrylate ( (Meth) acrylic acid ester; and the like.

  These (meth) acrylic acid esters can be used alone or in combination of two or more. Among these, (meth) acrylic acid alkyl ester is preferable, and methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate and alkyl groups have 6 to 12 carbon atoms. (Meth) acrylic acid alkyl ester is more preferred. By selecting these, it becomes possible to reduce the swelling property with respect to the electrolytic solution, and to improve the cycle characteristics.

  The content ratio of (meth) acrylic acid ester units in the dispersion-type binder is preferably 50 to 95% by weight, more preferably 60 to 90% by weight. By setting the content ratio of the (meth) acrylic acid ester unit in the above range, the flexibility in forming the electrode can be improved, and the resistance to cracking can be increased.

  The acrylate polymer may be a copolymer of the above-described (meth) acrylic acid ester and a monomer copolymerizable therewith. As such a copolymerizable monomer, Examples thereof include an α, β-unsaturated nitrile monomer and a vinyl monomer having an acid component.

  Examples of the α, β-unsaturated nitrile monomer include acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-bromoacrylonitrile and the like. These may be used alone or in combination of two or more. Among these, acrylonitrile and methacrylonitrile are preferable, and acrylonitrile is more preferable.

  The content of the α, β-unsaturated nitrile monomer unit in the dispersion-type binder is usually 0.1 to 40% by weight, preferably 0.5 to 30% by weight, more preferably 1 to 20 parts by weight. It is. By setting the content ratio of the α, β-unsaturated nitrile monomer unit in the above range, the binding force as the binder can be further increased.

  Examples of the vinyl monomer having an acid component include acrylic acid, methacrylic acid, itaconic acid, maleic acid, and fumaric acid. These may be used alone or in combination of two or more. Among these, acrylic acid, methacrylic acid and itaconic acid are preferable, methacrylic acid and itaconic acid are more preferable, and it is particularly preferable to use methacrylic acid and itaconic acid in combination.

  The content ratio of the vinyl monomer unit having an acid component in the dispersion-type binder is preferably 10 to 1.0% by weight, more preferably 1.5 to 5.0% by weight. By making the content rate of the vinyl monomer unit which has an acid component into the said range, stability at the time of setting it as a slurry can be improved.

  Further, the acrylate polymer may be a copolymer of other monomers copolymerizable with the above-described monomers. Examples of such other monomers include 2 Carboxylic acid esters having two or more carbon-carbon double bonds, aromatic vinyl monomers, amide monomers, olefins, diene monomers, vinyl ketones, heterocyclic ring-containing vinyl compounds, etc. It is done.

  The shape of the dispersion-type binder is not particularly limited, but is preferably particulate. By being particulate, the binding property is good, and it is possible to suppress deterioration of the capacity of the manufactured electrode and deterioration due to repeated charge and discharge. Examples of the particulate binder include those in which binder particles such as latex are dispersed in water, and powders obtained by drying such a dispersion.

  The volume average particle diameter of the dispersion-type binder is preferably 0.001 to 100 μm, more preferably 10 to 1000 nm, and still more preferably 50 to 500 nm. By setting the average particle diameter of the dispersion-type binder particles in the above range, the strength and flexibility as the obtained electrode are improved while the stability in the slurry is improved.

  The amount of the binder is usually 0.1 to 50 parts by weight, preferably 0.5 to 20 parts by weight, more preferably 1 to 15 parts by weight based on 100 parts by weight of the electrode active material. is there. When the amount of the binder is within this range, sufficient adhesion between the obtained electrode mixture layer and the current collector can be secured, and the internal resistance can be lowered.

  As described above, a dispersant may be used for the composite particles as necessary. Specific examples of the dispersant include cellulosic polymers such as carboxymethylcellulose, methylcellulose, ethylcellulose and hydroxypropylcellulose, and ammonium salts or alkali metal salts thereof, alginates such as propylene glycol alginate, and alginates such as sodium alginate. , Polyacrylic acid, and polyacrylic acid (or methacrylic acid) salts such as sodium polyacrylic acid (or methacrylic acid), polyvinyl alcohol, modified polyvinyl alcohol, polyethylene oxide, polyvinyl pyrrolidone, polycarboxylic acid, oxidized starch, phosphoric acid starch , Casein, various modified starches, chitin, chitosan derivatives and the like. These dispersants can be used alone or in combination of two or more. Among these, a cellulose polymer is preferable, and carboxymethyl cellulose or an ammonium salt or an alkali metal salt thereof is particularly preferable. The amount of these dispersants used is not particularly limited as long as the effect of the present invention is not impaired, but is usually 0.1 to 10 parts by weight, preferably 0, with respect to 100 parts by weight of the electrode active material. .5 to 5 parts by weight, more preferably 0.8 to 2 parts by weight.

  The composite particles are obtained by granulating using an electrode active material, a binder, and other components such as the conductive material added as necessary, and include at least an electrode active material and a binder, Each of the above does not exist as an independent particle, but forms one particle by two or more components including an electrode active material and a binder as constituent components. Specifically, a plurality of individual particles of the two or more components are combined to form secondary particles, and a plurality (preferably several to several tens) of electrode active materials are formed by a binder. Those that are bound to form particles are preferred.

  When the conductive material is added to the composite particles, the content of the conductive material is preferably 0.1 to 50 parts by weight, more preferably 0.5 to 15 parts by weight, and still more preferably 100 parts by weight of the electrode active material. Is 1 to 10 parts by weight. By setting the content ratio of the conductive material in the above range, the internal resistance can be sufficiently reduced while keeping the capacity of the obtained electricity storage device high.

The shape of the composite particles is preferably substantially spherical from the viewpoint of fluidity. That is, the short axis diameter of the composite particles is L _s , the long axis diameter is L _l , L _a = (L _s + L _l ) / 2, and a value of (1− (L ₁ −L _s ) / L _a ) × 100 Is a sphericity (%), the sphericity is preferably 80% or more, more preferably 90% or more.

Here, the minor axis diameter L _s and the major axis diameter L _l are values measured from a scanning electron micrograph image.

  The volume average particle diameter of the composite particles is usually in the range of 0.1 to 1000 μm, preferably 1 to 200 μm, more preferably 30 to 150 μm. By making the volume average particle diameter of the composite particles in this range, an electrode mixture layer having a desired thickness can be easily obtained, which is preferable.

  The average particle size of the composite particles is a volume average particle size calculated by measuring with a laser diffraction particle size distribution measuring device (for example, SALD-3100; manufactured by Shimadzu Corporation).

  The structure of the composite particle is not particularly limited, but a structure in which the binder is uniformly dispersed in the composite particle without being unevenly distributed on the surface of the composite particle is preferable.

  The method for producing the composite particles is not particularly limited, but the composite particles can be easily obtained by the following two production methods.

  The first method for producing composite particles is a fluidized bed granulation method. In the fluidized bed granulation method, a step of obtaining a slurry containing a binder and, if necessary, a conductive material, a dispersing agent and other additives, the electrode active material is caused to flow in a heated air stream, The slurry is sprayed to bind the electrode active materials to each other and dry the slurry. Hereinafter, the fluidized bed granule method will be described.

(Fluidized bed granulation method)
First, a slurry containing a binder and, if necessary, a conductive material, a dispersant, and other additives is obtained. Water is most preferably used as the solvent used to obtain the slurry, but an organic solvent can also be used. Examples of the organic solvent include alkyl alcohols such as methyl alcohol, ethyl alcohol and propyl alcohol; alkyl ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran, dioxane and diglyme; diethylformamide, dimethylacetamide and N-methyl- Examples include 2-pyrrolidone (hereinafter sometimes referred to as NMP) and amides such as dimethylimidazolidinone, and alkyl alcohols are preferred. When an organic solvent having a lower boiling point than water is used in combination, the drying rate can be increased during fluid granulation. In addition, when an organic solvent having a boiling point lower than that of water is used in combination, the dispersibility of the binder or the solubility of the soluble resin is changed, and the viscosity and fluidity of the slurry can be adjusted depending on the amount or type of the solvent. Can be improved.

  The amount of the solvent used when preparing the slurry is such that the solid content concentration of the slurry is usually in the range of 1 to 50% by weight, preferably 5 to 50% by weight, more preferably 10 to 30% by weight. Amount. When the amount of the solvent is within this range, it is preferable because the binder is uniformly dispersed.

  There is no particular limitation on the method or procedure for dispersing or dissolving the binder, and if necessary, the conductive material, the dispersant and other additives in the solvent. For example, the binder, the conductive material, the dispersant and the other in the solvent. Method of adding and mixing additives, after dissolving the dispersant in the solvent, adding and mixing the binder (for example, latex) dispersed in the solvent, and finally adding the conductive material and other additives And a method in which a conductive material is added to a dispersant dissolved in a solvent and mixed, and a binder dispersed in a solvent is added thereto and mixed. Examples of the mixing means include mixing equipment such as a ball mill, a sand mill, a bead mill, a pigment disperser, a crusher, an ultrasonic disperser, a homogenizer, and a planetary mixer. Mixing is usually performed in the range of room temperature to 80 ° C. for 10 minutes to several hours.

  Next, the electrode active material is fluidized, and the slurry is sprayed thereon for fluid granulation. Examples of fluidized granulation include a fluidized bed, a deformed fluidized bed, and a spouted bed. In the fluidized bed method, the electrode active material is fluidized with hot air, and the slurry is sprayed from the spray or the like to perform agglomeration and granulation. The modified fluidized bed is the same as the fluidized bed, but is a method of giving a circulating flow to the powder in the bed and discharging the granulated material that has grown relatively large by using the classification effect. In addition, the method using the spouted bed is a method in which slurry from a spray or the like is attached to coarse particles using the characteristics of the spouted bed and granulated while being dried at the same time. As the method for producing composite particles in the present invention, a fluidized bed or a deformed fluidized bed is preferred among these three methods.

  The temperature of the slurry to be sprayed is usually room temperature, but may be heated to room temperature or higher. The temperature of the hot air used for fluidization is usually 70 to 300 ° C, preferably 80 to 200 ° C.

  By the above production method, composite particles containing an electrode active material, a binder, and, if necessary, a conductive material, a dispersant, and other additives can be obtained.

  The second production method of the composite particles is a spray drying granulation method. The spray drying granulation method described below is preferable because the composite particles of the present invention can be obtained relatively easily. Hereinafter, the spray drying granulation method will be described.

(Spray drying granulation method)
First, a slurry for composite particles containing an electrode active material and a binder is prepared. The slurry for composite particles can be prepared by dispersing or dissolving an electrode active material, a binder, and a conductive material added as necessary in a solvent. In this case, when the binder is dispersed in water as a dispersion medium, it can be added in a state dispersed in water.

  As the solvent used for obtaining the composite particle slurry, water is usually used, but a mixed solvent of water and an organic solvent may be used. Examples of the organic solvent that can be used in this case include alkyl alcohols such as methyl alcohol, ethyl alcohol, and propyl alcohol, alkyl ketones such as acetone and methyl ethyl ketone, ethers such as tetrahydrofuran, dioxane, and diglyme, diethylformamide, Examples thereof include amides such as dimethylacetamide, N-methyl-2-pyrrolidone, and dimethylimidazolidinone. Among these, alcohols are preferable. By using water and an organic solvent having a lower boiling point than water, the drying rate can be increased during spray drying. Thereby, the viscosity and fluidity of the slurry for composite particles can be adjusted, and the production efficiency can be improved.

  The viscosity of the composite particle slurry is preferably in the range of 10 to 3,000 mPa · s, more preferably 30 to 1,500 mPa · s, and still more preferably 50 to 1,000 mPa · s at room temperature. When the viscosity of the slurry for composite particles is within this range, the productivity of the spray drying granulation step can be increased.

  Moreover, in this invention, when preparing the slurry for composite particles, you may add a dispersing agent and surfactant as needed.

  Examples of the surfactant include amphoteric surfactants such as anionic, cationic, nonionic, and nonionic anions, and anionic or nonionic surfactants that are easily thermally decomposed are preferable. The compounding amount of the surfactant is preferably 50 parts by weight or less, more preferably 0.1 to 10 parts by weight, and further preferably 0.5 to 5 parts by weight with respect to 100 parts by weight of the positive electrode active material. .

  The method or order of dispersing or dissolving the electrode active material, the binder, and the conductive material added as necessary in the solvent is not particularly limited. Moreover, as a mixing apparatus, a ball mill, a sand mill, a bead mill, a pigment disperser, a crusher, an ultrasonic disperser, a homogenizer, a homomixer, a planetary mixer, etc. can be used, for example. Mixing is usually performed in the range of room temperature to 80 ° C. for 10 minutes to several hours.

  Subsequently, the obtained slurry for composite particles is granulated by spray drying. Spray drying is a method of spraying and drying a slurry in hot air. An atomizer is used as an apparatus used for spraying slurry. There are two types of atomizers: a rotating disk system and a pressurizing system. In the rotating disk system, slurry is introduced almost at the center of a disk that rotates at high speed, and the slurry is removed from the disk by the centrifugal force of the disk. In this case, the slurry is atomized. In the rotating disk system, the rotational speed of the disk depends on the size of the disk, but is usually 5,000 to 30,000 rpm, preferably 15,000 to 30,000 rpm. The lower the rotational speed of the disk, the larger the spray droplets and the larger the average particle size of the resulting composite particles. Examples of the rotating disk type atomizer include a pin type and a vane type, and a pin type atomizer is preferable. A pin-type atomizer is a type of centrifugal spraying device that uses a spraying plate, and the spraying plate has a plurality of spraying rollers removably mounted on a concentric circle along its periphery between upper and lower mounting disks. It consists of The slurry for composite particles is introduced from the center of the spray disk, adheres to the spray roller by centrifugal force, moves outward on the roller surface, and finally sprays away from the roller surface. On the other hand, the pressurization method is a method in which the slurry for composite particles is pressurized and sprayed from a nozzle to be dried.

  The temperature of the slurry for composite particles to be sprayed is usually room temperature, but may be higher than room temperature by heating. Moreover, the hot air temperature at the time of spray-drying is 80-250 degreeC normally, Preferably it is 100-200 degreeC. In the spray drying method, the method of blowing hot air is not particularly limited. For example, the method in which the hot air and the spraying direction flow side by side, the method in which the hot air is sprayed at the top of the drying tower and descends with the hot air, and the sprayed droplets and hot air flow countercurrently. Examples include a contact method, and a method in which sprayed droplets first flow in parallel with hot air, then drop by gravity and contact countercurrent.

  In addition to the method of spraying the composite particle slurry having the electrode active material and the binder in a lump as the spraying method, the slurry containing the binder and other additives as required is fluidized. A method of spraying on the electrode active material can also be used. From the standpoint of ease of particle size control, productivity, and reduction in particle size distribution, an optimal method may be appropriately selected according to the components of the composite particles.

  The electrode mixture layer produced by the dry molding method includes the composite particles described above. The composite particles can obtain an electrode mixture layer having desired physical properties by containing other binders and other additives alone or as necessary. The content of the composite particles contained in the electrode mixture layer is preferably 50% by weight or more, more preferably 70% by weight or more, and further preferably 90% by weight or more.

  As another binder used as necessary, for example, the binder contained in the composite particles described above can be used. Since the composite particles already contain a binder, it is not necessary to add another binder separately when manufacturing the electrode composite layer, but in order to further increase the binding force between the composite particles. Other binders may be added. In addition, when the other binder is added, the amount of the other binder added is preferably 0.01 with respect to 100 parts by weight of the electrode active material in total with the binder in the composite particles. -10 parts by weight, more preferably 0.1-5 parts by weight. Other additives include molding aids such as water and alcohol, and these can be added by appropriately selecting an amount that does not impair the effects of the present invention.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated further more concretely, this invention is not limited to the following Example. Parts and% are based on weight unless otherwise specified.

100 parts of an electrode active material (activated carbon with a specific surface area of 2000 m ² / g and a weight average particle size of 5 μm), 5 parts of a conductive material (acetylene black “Denka black powder”: manufactured by Denki Kagaku Kogyo Co., Ltd.), a dispersion-type binder (40% aqueous dispersion of cross-linked acrylate polymer having a number average particle size of 0.15 μm and a glass transition temperature of −40 ° C .: “AD211”; manufactured by Nippon Zeon Co., Ltd.) 7.5 parts, soluble resin (carboxy 93.3 parts of a 1.5% aqueous solution of methylcellulose “DN-800H” (manufactured by Daicel Chemical Industries, Ltd.) and 231.8 parts of ion-exchanged water K. The mixture was stirred and mixed with a homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) to obtain a slurry having a solid content of 25%. Next, the slurry was spray-dried with hot air at 150 ° C. using a spray dryer (with a pin type atomizer manufactured by Okawara Chemical Industries Co., Ltd.) to obtain spherical composite particles having a weight average particle size of 50 μm. The weight average particle size of the composite particles was measured using a powder measuring device (Powder Tester PT-S: manufactured by Hosokawa Micron Corporation). The above process is referred to as process I.

  As shown in FIG. 1, the roll press machine has a pair of rolls 4 </ b> A and 4 </ b> B that rotate in parallel and rotate downward in the proximity portion, and a pair of dents that are installed above the pair of rolls. Partition plates 8A and 8B, and a pair of ribbon-like films 12 attached from the upper side to the lower side through the gap between the pair of rolls. The ribbon-like film 12 is attached so that it touches the base material (base film) 16 or the roll 4A but does not touch the partition plates 8A and 8B. Furthermore, the ribbon-like film 12 is attached so as to pass through a gap between the roll 4A and the partition plates 8A and 8B. The roll gap is 400 μm.

  In this roll press machine, a substrate film (PET, thickness 50 μm) 16 is unwound from the substrate unwinding roll 14, passed through the guide roll 18, and held by one roll 4 A, and a pair of rolls 4 A, 4 B After passing through, it set so that it might wind up to the base-material winding roll 22 through another guide roll 20.

As shown in FIG. 2, both ends of the base film 16 were allowed to pass through the gaps between the ribbon-shaped film 12 and the roll 4A. The composite particles (powder 6) obtained above were heated at 100 ° C. for 1 hour, and the roll press machine (pressed rough surface heat roll; manufactured by Hirano Giken Co., Ltd.) operated at a speed of 10 m / min. It supplied to the dent in the upper part of the roll for a press (roll temperature 100 degreeC, press linear pressure 10kN / cm). As a result, a two-layer sheet in which the base film 16 and the powder layer were laminated was obtained. This two-layer sheet had an average film thickness of 450.2 μm, a standard deviation of 3.5%, a variation coefficient of 0.7%, an average density of 0.452 mg / cm ³ , a standard deviation of 0.5%, and a variation coefficient of 1.0%. The coefficient of variation shown here is obtained by dividing the standard deviation by the average value, and is described as an index indicating variation.

Using the composite particles (powder 6) obtained in Step I of Example 1, a two-layer sheet obtained by laminating a base film 16 and a powder layer obtained in the same procedure as in Example 1 In the same manner as in Example 1, a powder layer was formed on the back side of the base film 16 to obtain a three-layer sheet. The powder layer formed on the back surface side had an average film thickness of 455.3 μm, a standard deviation of 19.7%, a coefficient of variation of 4.3%, an average density of 0.427 mg / cm ³ , a standard deviation of 1.8%, and a coefficient of variation of 4.2%.

Comparative Example 1

Using the composite particles obtained by the same method as in Step I of Example 1, a two-layer sheet was obtained in the same manner as in Example 1 except that the ribbon-like film was not used. The two-layer sheet had an average film thickness of 456.3 μm, a standard deviation of 6.4%, and a coefficient of variation of 1.4%, an average density of 0.453 mg / cm ³ , a standard deviation of 0.7%, and a coefficient of variation of 1.5%. However, white streaks were found in the vicinity of the boundary line between the base film and the powder layer in the sheet-like molded body.

Comparative Example 2

Using the composite particles obtained in the same manner as in Step I of Example 1, and using a two-layer sheet obtained by laminating the base film 16 and the powder layer in the same procedure as in Example 1. In the same manner as in Comparative Example 1, a powder layer was formed on the back side without using a base film to obtain a three-layer sheet. The powder layer formed on the back side had a film thickness of 478.3 μm, a standard deviation of 26.4%, a coefficient of variation of 5.5%, an average density of 0.434 mg / cm ³ , a standard deviation of 2.3%, and a coefficient of variation of 5.3%. The obtained sheet could not be said to have good film thickness accuracy, and wrinkles that regularly entered the sheet due to the forming pressure occurred.

  By using the ribbon-like film from Example 1 and Comparative Example 1, it was found that the film thickness accuracy was improved and the appearance was improved due to the effect of eliminating white streaks generated on the substrate. Example 2 and Comparative Example 2 suggested an improvement in film thickness accuracy by the ribbon-like film and suppression of wrinkle generation by the ribbon-like film. Note that this experiment was performed with N = 3, and in all cases, the same tendency was obtained. Even in the experiment repeated, similar results were obtained in improving the film thickness accuracy and improving the appearance.

(Measurement method of powder layer thickness and variation)
The thickness of the powder layer was measured using a contact digital thickness gauge (JIS-K6250, manufactured by Toyo Seiki Co., Ltd.), and 10 points were measured at intervals of 2 cm to obtain an average value and variation. From the above Examples and Comparative Examples, it can be seen that the sheet-like molded bodies of Examples 1 to 3 manufactured by the manufacturing method of the present invention have a small thickness variation and a small standard deviation. On the other hand, it can be seen that the sheet-like molded bodies of Comparative Examples 1 to 3 manufactured by the conventional method have a large thickness variation and a large standard deviation.

(Measurement method of powder layer density)
The sheet-like molded body was punched into a size of Φ16 mm, the weight and volume were measured, and the density of the powder layer excluding the base material portion was calculated. Moreover, the density of the powder layer shown in Example 3 and Comparative Example 3 was calculated by measuring the film thickness on both surfaces and subtracting the substrate film thickness by peeling off one surface.

2,200,202,204 ... powder forming apparatus, 4 ... compression roll, 4A, 4B ... roll, 5 ... groove, 6 ... powder, 8A, 8B ... partition plate, 12 ... ribbon-like film, 14 ... substrate Unwinding roll, 16 ... base material, 22 ... base material winding roll

Claims (12)

A pair of rolls whose rotation axes are parallel and rotate in opposite directions;
A powder storage section storing powder supplied between the pair of rolls;
A base material transport unit for transporting the base material between the pair of rolls so as to hold one of the pair of rolls;
A powder characterized in that the powder supplied from the powder reservoir is rolled on the substrate in a state in which the pressure from the pair of rolls is hardly applied to both ends in the width direction of the substrate. Molding equipment.   The powder molding apparatus according to claim 1, further comprising a film placed on the surfaces of both end portions of the base material.   The powder molding apparatus according to claim 2, wherein the film has a thickness of 10 μm to 500 μm. Further comprising a pair of partition plates installed at both ends of a recess formed above the pair of rolls,
4. The powder molding apparatus according to claim 2, wherein the film is disposed so as to contact the base material or the roll and not contact the partition plate.   The powder forming apparatus according to any one of claims 2 to 4, wherein the film is disposed so as to pass through a gap between the roll and the partition plate.   The powder molding apparatus according to any one of claims 2 to 5, wherein the film is capable of changing a position in a width direction of the base material in accordance with a width of the base material.   The axial length of the other roll of the pair of rolls is made shorter than the axial length of the one roll so as not to face both ends of the base material. The powder molding apparatus according to claim 1.   The powder molding apparatus according to claim 1, wherein grooves are provided at both ends of the other roll of the pair of rolls.   2. The powder forming apparatus according to claim 1, wherein a length of the pair of rolls in an axial direction is substantially equal to a width of a powder to be roll-formed on the base material.   The powder forming apparatus according to claim 1, wherein non-rotating sleeves are provided at both ends of the other roll of the pair of rolls.   The axial length of the other roll of the pair of rolls is made shorter than the axial length of the one roll, and is stopped at both ends of the other roll or the other roll The powder forming apparatus according to claim 1, further comprising an end roll that rotates in a reverse direction.   Using the powder forming apparatus according to any one of claims 1 to 11, the powder supplied from the powder storage unit is rolled and formed with the pair of rolls, and a powder layer is formed on the substrate. Manufacturing method of powder molded sheet to be laminated.

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