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CN-117779279-B - Glass cloth, prepreg and printed circuit board

CN117779279BCN 117779279 BCN117779279 BCN 117779279BCN-117779279-B

Abstract

Provided are a low dielectric glass cloth which has little looseness and uniform characteristics of thickness, air permeability and resin impregnation, and a prepreg and a printed circuit board obtained by using the glass cloth. A glass cloth comprising a warp yarn and a weft yarn, wherein the warp yarn and the weft yarn are glass yarns formed of a plurality of glass filaments, the glass cloth has a thickness of 5 [ mu ] m to 100 [ mu ] m, the glass cloth has a length in the width direction of 1000mm or more, and a difference X between the warp widths at the widthwise end and widthwise center of the glass cloth is equal to or less than a standard deviation alpha of the warp widths.

Inventors

  • TODO MASAAKI
  • KODA HIROSHI
  • YOKOE TOMOYUKI
  • MISHINA HITOSHI
  • Persimmon Yung Aang

Assignees

  • 旭化成株式会社

Dates

Publication Date
20260508
Application Date
20230927
Priority Date
20220927

Claims (20)

  1. 1. A glass cloth comprising a warp yarn and a weft yarn, which are glass yarns formed of a plurality of glass filaments, wherein the glass cloth has a thickness of 5 μm to 100 μm, The length of the glass cloth in the width direction is more than 1000mm, and The difference X between the warp widths of the widthwise end portions and the widthwise central portion of the glass cloth is equal to or less than the standard deviation alpha of the warp widths of the glass cloth width.
  2. 2. The glass cloth according to claim 1, wherein the difference X in warp widths is 0.7 times or less of the standard deviation α of the warp widths of the glass cloth width amounts.
  3. 3. The glass cloth according to claim 1, wherein the difference X in warp widths is 0.5 times or less of the standard deviation α of the warp widths of the glass cloth width amounts.
  4. 4. The glass cloth according to claim 1 or 2, wherein the standard deviation α of the warp widths of the glass cloth width amounts is 0.08 times or less of the average β of the warp widths of the glass cloth width amounts.
  5. 5. The glass cloth according to claim 1 or 2, wherein the standard deviation α of the warp widths of the glass cloth width amounts is 0.04 times or less of the average β of the warp widths of the glass cloth width amounts.
  6. 6. The glass cloth according to claim 1 or 2, wherein the standard deviation α of the warp widths of the glass cloth width amounts is 0.03 times or less of the average β of the warp widths of the glass cloth width amounts.
  7. 7. The glass cloth according to claim 1 or 2, wherein the TEX of the glass yarn is 1.0 or more and 25 or less.
  8. 8. The glass cloth according to claim 1 or 2, wherein the TEX of the glass yarn is 1.5 or more and 23 or less.
  9. 9. The glass cloth according to claim 1 or 2, wherein the TEX of the glass yarn is 2.0 or more and 21 or less.
  10. 10. The glass cloth according to claim 1 or 2, which is composed of glass yarns having an elastic modulus of 50GPa or more and 70GPa or less.
  11. 11. The glass cloth according to claim 1 or 2, which is composed of glass yarns having an elastic modulus of 50GPa or more and 63GPa or less.
  12. 12. The glass cloth according to claim 1 or 2, which is composed of glass yarns having an elastic modulus of 52GPa or more and 63GPa or less.
  13. 13. The glass cloth according to claim 1 or 2, wherein the dielectric constant is 5.0 or less at a frequency of 1 GHz.
  14. 14. The glass cloth according to claim 1 or 2, wherein the warp and weft constituting the glass cloth have a driving density of 30 to 120/25 mm.
  15. 15. The glass cloth according to claim 1 or 2, wherein the average diameters of glass monofilaments constituting warp yarns and weft yarns are each independently 2.5 to 9 μm.
  16. 16. The glass cloth according to claim 1 or 2, wherein the average number of glass filaments constituting warp yarns and weft yarns is 20 to 250.
  17. 17. The glass cloth according to claim 1 or 2, having a weight loss on intense heat in a range of 0.25 mass% to 1.5 mass%.
  18. 18. The glass cloth according to claim 1 or 2, wherein a sum of a boron content and a phosphorus content in the glass cloth is 5 mass% or more and 20 mass% or less.
  19. 19. The glass cloth according to claim 1 or 2, wherein a sum of a boron content and a phosphorus content in the glass cloth is 6.5 mass% or more and 20 mass% or less.
  20. 20. A prepreg having the glass cloth of claim 1 or 2 and a base resin composition impregnated in the glass cloth.

Description

Glass cloth, prepreg and printed circuit board Technical Field The present invention relates to a glass cloth, a prepreg, and a printed circuit board. Background With the recent development of information communication society, data communication and/or signal processing is being performed at a high capacity and high speed, and low dielectric power of printed circuit boards used in communication devices or meters such as high-end servers, high-end routers/switches, supercomputers, and base stations is being remarkably advanced. Accordingly, various low dielectric glass cloths have been proposed for glass cloths constituting printed circuit boards. For example, the low dielectric glass cloth disclosed in patent document 1 realizes a low dielectric constant by blending a large amount of boron oxide (B 2O3) into the glass composition of the E glass cloth that has been conventionally used, and adjusting the blending amount of other components such as silica (SiO 2). As a method for improving the variation in the performance and quality of the low dielectric glass cloth in the width direction, patent document 2 discloses a glass cloth with improved end relaxation of the low dielectric glass cloth, and patent document 3 discloses a glass cloth with improved warp of the substrate. Prior art literature Patent literature Patent document 1 Japanese patent application laid-open No. 2010-508226 Patent document 2 International publication No. 2021/124913 Patent document 3 Japanese patent application laid-open No. 2017-132651 Disclosure of Invention Problems to be solved by the invention The present inventors have studied and found that the low dielectric glass cloth produced by using such low dielectric glass yarn has a significant difference in performance and quality from the E glass cloth used in the past. The low dielectric glass cloth tends to be more relaxed than the conventional E glass cloth. Particularly, significant looseness occurs at the widthwise end portions and the central portion. This is presumably because the low dielectric glass cloth has a low elastic modulus and the texture of the glass cloth is soft. Further, the inventors of the present invention have found that, as a result of examining the low dielectric glass cloth in detail, the thickness distribution in the width direction is different, and the thickness at the end portions in the width direction tends to be about 1 thicker than the thickness at the central portion. Further, it is clear that characteristics such as air permeability and resin impregnation property are different in the width direction, particularly in the width direction end portions. Such variations in the performance and quality of the glass cloth also affect the characteristics and quality (such as resin content, heat resistance, copper foil peel strength, and dimensional stability) of prepregs, laminates for printed wiring boards, and the like obtained by using the glass cloth. Regarding the glass cloth disclosed in patent document 2, it is disclosed that the end portion relaxation of the glass cloth is improved by suppressing the difference in slope between the end portion and the central portion in the width direction of the stress-strain curve in the direction parallel to the warp yarn to 10% or less. However, the glass cloth disclosed in patent document 2 has room for improvement in terms of relaxation of the low dielectric glass cloth. Regarding the glass cloth disclosed in patent document 3, a low dielectric glass cloth is disclosed that improves warpage of a substrate by suppressing a width direction difference in an elongation of a stress-strain curve in a warp direction to 10% or less. However, since warp of the substrate is also significantly related to elongation in the weft direction, and in general, glass cloth has a characteristic that weft is significantly elongated as compared with warp, warp of the substrate cannot be improved only by controlling the elongation of warp, and there is room for improvement in relaxation of the glass cloth. The present invention has been made in view of the above-described problems, and an object thereof is to provide a low dielectric glass cloth having less relaxation and uniform characteristics of thickness, air permeability and resin impregnation, and a prepreg and a printed circuit board obtained by using the glass cloth. Solution for solving the problem The present inventors have made intensive studies to solve the above problems, and as a result, have found that the above problems can be solved by setting the difference in warp width between the end portions and the central portion of the glass cloth to a predetermined range with respect to the difference in warp width, and have completed the present invention. Namely, the present invention is as follows. [ Item 1] A glass cloth comprising a warp yarn and a weft yarn, which are glass yarns formed of a plurality of glass filaments, wherein the glass cloth has a thickness o