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US-12623447-B2 - Methods for manufacturing laminated plate and heat generator, and defroster

US12623447B2US 12623447 B2US12623447 B2US 12623447B2US-12623447-B2

Abstract

Provided is a method for manufacturing a laminate that is excellent in adhesion between the copper foil and the resin film while using a polyvinyl acetal resin having low reactivity with the copper foil. This method includes the steps of providing a copper foil having on at least one side a treated surface on which an amount of nitrogen is 3.0 atomic % or more and 20.0 atomic % or less, and attaching or forming a polyvinyl acetal resin film on the treated surface of the copper foil to form a laminate. The amount of nitrogen is a proportion of N in a total amount of N, O, Si, P, S, Cl, Cr, Ni, Cu, Zn, Mo, Co, W, and Fe when the treated surface is subjected to elemental analysis by X-ray photoelectron spectroscopy (XPS).

Inventors

  • Makoto Hosokawa
  • Toshiyuki Shimizu

Assignees

  • MITSUI MINING & SMELTING CO., LTD.

Dates

Publication Date
20260512
Application Date
20220208
Priority Date
20210219

Claims (14)

  1. 1 . A method for manufacturing a laminate, comprising: providing a copper foil having on at least one side a treated surface on which an amount of nitrogen is 3.0 atomic % or more and 20.0 atomic % or less, and attaching or forming a polyvinyl acetal resin film on the treated surface of the copper foil to form a laminate, wherein the amount of nitrogen is a proportion of N in a total amount of N, O, Si, P, S, Cl, Cr, Ni, Cu, Zn, Mo, Co, W, and Fe when the treated surface is subjected to elemental analysis by X-ray photoelectron spectroscopy (XPS), and wherein the treated surface has a density of peaks Spd of 100 mm −2 or more and 26000 mm −2 or less, and wherein the Spd is a value measured in accordance with ISO 25178 under conditions in which a cutoff wavelength of an S-filter is 2 μm, and cutoff of an L-filter is not performed.
  2. 2 . The method according to claim 1 , wherein the amount of nitrogen is 4.0 atomic % or more and 17.0 atomic % or less.
  3. 3 . The method according to claim 1 , wherein the amount of nitrogen is 5.0 atomic % or more and 8.5 atomic % or less.
  4. 4 . The method according to claim 3 , wherein the treated surface comprises Si, and has a N/Si ratio being a ratio of N to Si of 1.0 or less when the treated surface is subjected to elemental analysis by X-ray photoelectron spectroscopy (XPS).
  5. 5 . The method according to claim 1 , wherein the treated surface comprises a nitrogen-containing compound.
  6. 6 . The method according to claim 5 , wherein the nitrogen-containing compound is a silane compound having an amino group.
  7. 7 . The method according to claim 1 , wherein the treated surface has a developed interfacial area ratio Sdr of 0.50% or more and 9.00% or less and a root mean square height Sq of 0.010 μm or more and 0.200 μm or less, and wherein the Sdr and Sq are values measured in accordance with ISO 25178 under conditions in which a cutoff wavelength of an S-filter is 0.55 μm, and a cutoff wavelength of an L-filter is 10 μm.
  8. 8 . The method according to claim 1 , wherein attachment of the resin film to the copper foil is performed by thermocompression-bonding the resin film and the copper foil at a temperature of 180° C. or less and a pressure of 0.6 MPa or less.
  9. 9 . The method according to claim 1 , wherein the resin film has a thickness of 1 μm or more and 1000 μm or less.
  10. 10 . A method for manufacturing a heating element, comprising: providing a laminate manufactured by the method according to claim 1 , processing the copper foil of the laminate to form a heating wire having a predetermined pattern, and attaching or forming an additional polyvinyl acetal resin film on the laminate in which the heating wire is formed, so as to sandwich the heating wire, to form a heating element.
  11. 11 . The method according to claim 10 , wherein the predetermined pattern comprises at least one pattern selected from the group consisting of a linear shape, a wavy line shape, a lattice shape, and a net shape.
  12. 12 . A defroster comprising a heating element manufactured by the method according to claim 10 .
  13. 13 . A method for manufacturing a laminate, comprising: providing a copper foil having on at least one side a treated surface on which an amount of nitrogen is 3.0 atomic % or more and 20.0 atomic % or less, and attaching or forming a polyvinyl acetal resin film on the treated surface of the copper foil to form a laminate, wherein the amount of nitrogen is a proportion of N in a total amount of N, O, Si, P, S, Cl, Cr, Ni, Cu, Zn, Mo, Co, W, and Fe when the treated surface is subjected to elemental analysis by X-ray photoelectron spectroscopy (XPS), and wherein the treated surface comprises a plurality of roughening particles.
  14. 14 . A method for manufacturing a laminate, comprising: providing a copper foil having on at least one side a treated surface on which an amount of nitrogen is 3.0 atomic % or more and 20.0 atomic % or less, and attaching or forming a polyvinyl acetal resin film on the treated surface of the copper foil to form a laminate, wherein the amount of nitrogen is a proportion of N in a total amount of N, O, Si, P, S, Cl, Cr, Ni, Cu, Zn, Mo, Co, W, and Fe when the treated surface is subjected to elemental analysis by X-ray photoelectron spectroscopy (XPS), and wherein the polyvinyl acetal resin is a polyvinyl butyral resin.

Description

TECHNICAL FIELD The present invention relates to methods for manufacturing a laminate and a heating element, and a defroster. BACKGROUND ART As apparatuses for preventing or removing the frosting, icing, clouding, and the like of window glass in vehicles such as automobiles, defrosters are widely used. With a defroster, for example, warm air comprising no steam is intensively blown into a place where dehumidification is desired, to remove clouding to ensure visibility. In recent years, for the purpose of the improvement of heating efficiency, power saving in electric vehicles, and the like, a defroster using a heating wire (electrically heated wire) has been required. With a defroster in this form, clouding can be removed, for example, by warming glass by a heating wire interposed between glass plates. It is known that when a heating wire is interposed between glass plates in such a defroster, a polyvinyl acetal resin (for example, a polyvinyl butyral resin) having high light transmission properties is used as a glass intermediate film. For example, Patent Literature 1 (JP2018-35036A) discloses that regarding a glass apparatus for a vehicle comprising a pair of glass substrates, and a transparent resin intermediate film and a heating electrode sheet interposed between the glass substrates, a polyvinyl butyral resin is used as the transparent resin intermediate film. As a heating wire for a defroster, a tungsten wire is generally used. However, a tungsten wire is thick having a wire diameter of about 30 μm and also difficult to thin and therefore provides poor visibility. In order to address such a problem, it is proposed that instead of a tungsten wire, a copper pattern that can be formed into a thin wire be used as a heating wire. For example, Patent Literature 2 (JP2018-161889A) discloses that regarding a polyvinyl acetal resin film having a polyvinyl acetal resin layer, and an electrically conductive structure based on a metal foil, disposed on the surface or inside of the polyvinyl acetal resin layer, the electrically conductive structure is composed of copper or the like. In addition, Patent Literature 3 (JP2019-142763A) discloses that a laminate in which a polyvinyl acetal resin film and a copper foil are superposed is thermocompression-bonded to obtain the polyvinyl acetal resin film to which the copper foil is attached, and then the copper foil attached to the resin film is processed to form an electrically conductive layer. Further, Patent Literature 4 (WO2017/090386) discloses that in a laminate having a resin layer comprising a polyvinyl acetal resin and a copper layer, the copper layer is processed by a method such as a subtractive process, a semi-additive process, and a modified semi-additive process to form a wiring pattern. Methods are known in which surface treatment such as rust proofing treatment and silane treatment is performed on a copper foil surface to improve the rust proofing properties, moisture resistance, chemical resistance, and the like of the copper foil. For example, Patent Literature 5 (JP2015-193884A) discloses that in Examples, rust proofing treatment composed of zinc-nickel alloy plating treatment and chromate treatment, and silane treatment with a silane coupling agent are performed in order on the roughening-treated layer of a carrier-attached copper foil as surface treatment. In addition, Patent Literature 6 (JP4354271B) discloses that in order to prevent the oxidative corrosion of a copper foil surface, organic rust proofing treatment using benzotriazole, imidazole, or the like is performed. CITATION LIST Patent Literature Patent Literature 1: JP2018-35036APatent Literature 2: JP2018-161889APatent Literature 3: JP2019-142763APatent Literature 4: WO2017/090386Patent Literature 5: JP2015-193884APatent Literature 6: JP4354271B SUMMARY OF INVENTION Regarding the formation of a laminate comprising a polyvinyl acetal resin film and a copper foil as disclosed in Patent Literature 3, a polyvinyl acetal resin is a thermoplastic resin, and the lamination of the copper foil and the resin film needs to be performed under the conditions of low temperature and low pressure (for example, 180° C. or less and 0.6 MPa or less) for a short time (for example, several tens of seconds or less). Therefore, a polyvinyl acetal resin results in low reactivity with a copper foil, and it is difficult to ensure adhesion between the copper foil and the resin film. The present inventors have now found that by attaching or forming a polyvinyl acetal resin film on a copper foil having a treated surface on which the amount of nitrogen is controlled in a predetermined range, it is possible to manufacture a laminate excellent in adhesion between the copper foil and the resin film. Therefore, it is an object of the present invention to manufacture a laminate that is excellent in adhesion between the copper foil and the resin film while using a polyvinyl acetal resin having low reactivity with the copper