US-12617931-B2 - Glass fiber-reinforced resin molded article

Abstract

Provided is a glass fiber-reinforced resin molded article with high mechanical strength and in which occurrence of undispersion of glass fiber is suppressed. In the glass fiber-reinforced resin molded article, glass fiber includes a flat cross-sectional shape having a minor axis D1 in the range of 3.0 μm or more and 10.5 μm or less and a major axis D2 in the range of 11.0 μm or more and 29.0 μm or less, the number average fiber length L (μm) of the glass fiber included in the glass fiber-reinforced resin molded article is in the range of 195 μm or more and less than 400 μm, the glass fiber content C (wt %) in the glass fiber-reinforced resin molded article is in the range of more than 50.0 wt % and 80.0 wt % or less, and the D1, D2, L, and C satisfy the following formula (1): 1200.0≤ C×L 2 /( D 1× D 2 2 )≤2550.0  (1).

Inventors

• Yosuke NUKUI
• Mao TAKAIZUMI
• Shunsuke KUSABA

Assignees

• NITTO BOSEKI CO., LTD.

Dates

Publication Date

20260505

Application Date

20190904

Priority Date

20190227

Claims (10)

1. 1 . A glass fiber-reinforced resin molded article, wherein glass fiber included in the glass fiber-reinforced resin molded article comprises a flat cross-sectional shape having a minor axis D1 in a range of 3.0 μm or more and 6.4 μm or less and a major axis D2 in a range of 11.0 μm or more and 26.0 μm or less, a number average fiber length L (μm) of the glass fiber included in the glass fiber-reinforced resin molded article is in a range of 195 μm or more and less than 275 μm, a glass fiber content C (wt %) in the glass fiber-reinforced resin molded article is in a range of 65.0 wt % or more and 70.0 wt % or less, and the D1, D2, L, and C satisfy following formula (1), with liquid crystal polymer being excluded from resin included in the glass fiber-reinforced resin molded article, the resin content in the glass fiber-reinforce resin molded article is in a range of 30.0 mass % or more, and the content of additive other than the glass fiber is in the range of 0 to 5 wt %: 1851.5≤ C×L 2 /( D 1× D 2 2 )≤2106.8 (1).
2. 2 . The glass fiber-reinforced resin molded article according to claim 1 , wherein the D1 is in a range of 4.0 μm or more and 6.0 μm or less, the D2 is in a range of 16.0 μm or more and 24.0 μm or less, the L is in a range of 205 μm or more and less than 275 μm, and the D1, D2, L, and C satisfy following formula (3): 1980.0≤ C×L 2 /( D 1× D 2 2 )≤2106.8 (3).
3. 3 . The glass fiber-reinforced resin molded article according to claim 1 , wherein a resin included in the glass fiber-reinforced resin molded article is a thermoplastic resin for injection molding selected from a group consisting of polyamide resins, polybutylene terephthalate resins, polycarbonate resins, polyarylene sulfide resins, and polyaryl ketone resins.
4. 4 . The glass fiber-reinforced resin molded article according to claim 3 , wherein the resin included in the glass fiber-reinforced resin molded article is polyamide resin.
5. 5 . A vehicle exterior member comprising the glass fiber-reinforced resin molded article according to claim 1 .
6. 6 . A vehicle interior member comprising the glass fiber-reinforced resin molded article according to claim 1 .
7. 7 . A vehicle engine member comprising the glass fiber-reinforced resin molded article according to claim 1 .
8. 8 . A vehicle mechanism component comprising the glass fiber-reinforced resin molded article according to claim 1 .
9. 9 . A vehicle muffler component comprising the glass fiber-reinforced resin molded article according to claim 1 .
10. 10 . An electronic device housing comprising the glass fiber-reinforced resin molded article according to claim 1 .

Description

TECHNICAL FIELD The present invention relates to a glass fiber-reinforced resin molded article. BACKGROUND ART Conventionally, glass fiber has been widely used in various applications to improve the performance of resin molded articles. Examples of the performance to be improved by glass fiber herein include mechanical strength such as tensile strength and bending strength of glass fiber-reinforced resin molded articles. So far, influences given by characteristics of glass fiber, such as the fiber diameter of glass fiber (glass fiber is usually composed of a plurality of glass filaments bundled, and the average diameter of the glass filaments is referred to as the fiber diameter of the glass fiber), the length of the glass fiber in a glass fiber-reinforced resin molded article, the glass content in the glass fiber-reinforced resin molded article, and the cross-sectional shape of glass filaments, on the mechanical strength of the glass fiber-reinforced resin molded article have been investigated (e.g., see Patent Literature 1). The following Patent Literature 2 describes a glass fiber-reinforced resin molded article in which the fiber diameter D (μm) of glass fiber included in the glass fiber-reinforced resin molded article is in the range of 3.0 to 12.0 μm, the number average fiber length L (μm) of the glass fiber included in the glass fiber-reinforced resin molded article is in the range of 160 to 350 μm, the glass fiber volume content V (%) in the glass fiber-reinforced resin molded article is in the range of 3.0 to 50.0%, and the above D, L, and V satisfy the following formula (6). 300.0≤D2×L/V≤1000.0  (6) CITATION LIST Patent Literature Patent Literature 1: Japanese Patent Laid-Open No. 2008-095066Patent Literature 2: No. WO 2018/159861 SUMMARY OF INVENTION Technical Problem Use of glass fiber-reinforced resin molded articles as metal substitute materials in the automotive field has expanded recently. In the automotive field, glass fiber-reinforced resin molded articles are required to have high mechanical strength (e.g., tensile strength and bending strength) in order to achieve the safety of drivers and durability of parts. Conventionally, in order to improve the mechanical strength of glass fiber-reinforced resin molded articles, increasing the length of glass fiber present in the glass fiber-reinforced resin molded articles has been contemplated. For example, in Patent Literature 1, the weight average fiber length of glass fiber present in a glass fiber-reinforced resin molded article is allowed to be 1 mm or more by using long fiber-reinforced resin pellets, obtained by impregnated glass fiber roving as continuous fiber with a resin melt. In the case where long fiber-reinforced resin pellets are used, however, a state referred to as undispersion is likely to occur, in which state, a portion of glass fiber (glass fiber is usually formed by a plurality of glass filaments bundled) in the glass fiber-reinforced resin molded article are not dispersed into a state of glass filaments and remains in a state of glass strands (in a form of a plurality of glass filaments bundled). When undispersion occurs, intense unevenness may occur depending on sites in the glass fiber-reinforced resin molded article. Particularly, in large glass fiber-reinforced resin molded articles such as automotive exterior parts, intense unevenness leads to stress concentration and may degrade the safety and durability of the glass fiber-reinforced resin molded article. The present invention has been made in view of the above situation, and an object thereof is to provide a glass fiber-reinforced resin molded article that has high mechanical strength and in which occurrence of undispersion of glass fiber is suppressed. Solution to Problem In order to achieve the object, in a glass fiber-reinforced resin molded article of the present invention, glass fiber included in the glass fiber-reinforced resin molded article comprises a flat cross-sectional shape having a minor axis D1 in the range of 3.0 μm or more and 10.5 μm or less and a major axis D2 in the range of 11.0 μm or more and 29.0 μm or less, the number average fiber length L (μm) of the glass fiber included in the glass fiber-reinforced resin molded article is in the range of 195 μm or more and less than 400 μm, the glass fiber content C (wt %) in the glass fiber-reinforced resin molded article is in the range of more than 50.0 wt % and 80.0 wt % or less, and the above D1, D2, L, and C satisfy the following formula (1). 1200.0≤C×L2/(D1×D22)≤2550.0  (1) According to the glass fiber-reinforced resin molded article of the present invention, the above D1, D2, L, and C being in the range described above and satisfying the condition of the above formula (1) allows the glass fiber-reinforced resin molded article to comprise high mechanical strength and suppresses occurrence of undispersion of the glass fiber. Here, comprising high mechanical strength means that the tensile strength o