US 12,286,731 B2Granted

Glass cloth, prepreg, and printed wiring board

AssigneeNitto Boseki Co., Ltd.

InventorsHiroyuki Kawanishi, Kazuaki Minami, Koichi Nakamura, Yuichiro Ito, Hirotaka Ikejiri

Life of this patent

Estimating the term…

Loading patent…

Abstract

Provided is a glass cloth that can reduce a delay time difference of a printed wiring board and for which high productivity can be achieved. In the glass cloth, a glass filament diameter of the warp yarn and the weft yarn is from 0.5 to 4.5 μm, the filament number of each is from 150 to 3000, the weaving density of each is from 1.0 to 50.0 filaments/25 mm, the average yarn width of each is from 550 to 10000 μm, the fiber-opening efficiency coefficient of each is from 0.600 to 1.500, the ratio of the filament number to the filament diameter is from 68.6 to 555.5, the geometric mean of the opening efficiency coefficients of the warp yarn and the weft yarn is from 0.770 to 1.200, and the thickness of the glass cloth is less than 10.0 μm.

A glass cloth composed of a warp yarn and a weft yarn, each of which is formed by bundling together a plurality of glass filaments, wherein

a filament diameter Dt of the glass filaments constituting the warp yarn and a filament diameter Dy of the glass filaments constituting the weft yarn are each independently in a range of 0.5 μm or more and 4.5 μm or less,
a filament number Ft of the glass filaments constituting the warp yarn and a filament number Fy of the glass filaments constituting the weft yarn are each independently in a range of 150 or more and 3000 or less,
a weaving density Wt of the warp yarn and a weaving density Wy of the weft yarn are each independently in a range of 1.0 filaments/25 mm or more and 50.0 filaments/25 mm or less,
an average yarn width Bt of the warp yarn and an average yarn width By of the weft yarn are each independently in a range of 550 μm or more and 10000 μm or less,
a warp yarn fiber-opening efficiency coefficient Pt determined from the Dt, Ft, Wt, and Bt using a following formula (1) is in a range of 0.600 or more and 1.500 or less, and a weft yarn fiber-opening efficiency coefficient Py determined from the Dy, Fy, Wy, and By using a following formula (2) is in a range of 0.600 or more and 1.500 or less,
Rt, which is a ratio (Ft/Dt) of the filament number Ft of the glass filaments constituting the warp yarn to the filament diameter Dt of the glass filaments constituting the warp yarn, and Ry, which is a ratio (Fy/Dy) of the filament number Fy of the glass filaments constituting the weft yarn to the filament diameter Dy of the glass filaments constituting the weft yarn, are each independently in a range of 68.6 or more and 555.5 or less,
the Pt and Py satisfy a following formula (3), and
the glass cloth has a thickness of less than 10.0 μm:
Pt
=
{
(
Bt
/
(
Dt
×
Ft
)
)
×
Bt
/
(
25000
/
Wt
)
}
1
/
2
×
{
(
D
⁢
t
×
Ft
)
/
(
25000
/
Wt
)
}
(
1
)
Py
=
{
(
By
/
(
Dy
×
F
⁢
y
)
)
×
By
/
(
25000
/
Wy
)
}
1
/
2
×
{
(
D
⁢
y
×
Fy
)
/
(
25000
/
Wy
)
}
(
2
)
0.77
≤
(
P
⁢
t
×
P
⁢
y
)
1
/
2
≤
1.2
.
(
3
)

113 more elements

Facts

Application

18/837,977Filed 1 Jun 2023

Priority

JP 2022-0929098 Jun 2022

Published

US 2025/0109530 A13 Apr 2025

Granted

29 Apr 2025

Term ends

Not estimatedThe source records don’t support an estimate.

Classification12 codes

D03D 1/0082
Woven fabrics designed to make specified articles: fabrics for printed circuit boards
C08J 5/24
Manufacture of articles or shaped materials containing macromolecular substances: impregnating materials with prepolymers which can be polymerised…
D03D 1/00
Woven fabrics designed to make specified articles
D03D 13/008
Woven fabrics characterised by the special disposition of the warp or weft threads, e.g. with curved weft threads, with discontinuous warp…:…

Abstract

Claims6