	US 12,104,044 B2
	Fiber-reinforced thermoplastic resin filament for 3D printer, and molded article thereof
Shoma Ishida, Nagoya (JP); Koji Suzuki, Nagoya (JP); and Yoshihiro Naruse, Nagoya (JP)
Assigned to Toray Industries, Inc., Tokyo (JP)
Appl. No. 17/433,647
Filed by Toray Industries, Inc., Tokyo (JP)
PCT Filed Apr. 3, 2020, PCT No. PCT/JP2020/015294 § 371(c)(1), (2) Date Aug. 25, 2021, PCT Pub. No. WO2020/217929, PCT Pub. Date Oct. 29, 2020.
Claims priority of application No. 2019-084176 (JP), filed on Apr. 25, 2019; application No. 2019-084177 (JP), filed on Apr. 25, 2019; application No. 2019-084178 (JP), filed on Apr. 25, 2019; and application No. 2019-084179 (JP), filed on Apr. 25, 2019.
Prior Publication US 2022/0145047 A1, May 12, 2022
Int. Cl. C08K 7/14 (2006.01); B33Y 70/10 (2020.01); C08L 35/02 (2006.01); C08L 61/02 (2006.01); C08L 81/04 (2006.01); B33Y 10/00 (2015.01); B33Y 80/00 (2015.01); C08K 3/04 (2006.01); C08K 3/40 (2006.01)

CPC C08K 7/14 (2013.01) [B33Y 70/10 (2020.01); C08L 35/02 (2013.01); C08L 61/02 (2013.01); C08L 81/04 (2013.01); B33Y 10/00 (2014.12); B33Y 80/00 (2014.12); C08K 3/04 (2013.01); C08K 3/40 (2013.01); C08L 2205/16 (2013.01); C08L 2207/04 (2013.01)]

12 Claims

1. A fiber-reinforced thermoplastic resin filament for a 3D printer, the fiber-reinforced thermoplastic resin filament comprising:

a thermoplastic resin impregnated into a plurality of continuous reinforcing fibers, wherein an average value S of a roundness parameter s of a cross section evaluated by a method is 60% to 100%, and a coefficient of variation of diameter lengths of circumscribed circles, which are bases of a plurality of roundness parameters s used to calculate the average value S, is 0% to 10%, wherein the roundness parameter s is determined by:

(i) taking a photograph of a cross section perpendicular to an axial direction of the fiber-reinforced thermoplastic resin filament for a 3D printer,

(ii) drawing an inscribed circle and a circumscribed circle of the filament in a cross-sectional image and determining a diameter of the inscribed circle and a diameter of the circumscribed circle,

(iii) calculating the roundness parameter s defined by equation (1), and

(iv) repeating (i)-(iii) at a plurality of locations on the fiber-reinforced thermoplastic resin filament for a 3D printer and calculating the average value S of the roundness parameter s

roundness parameter s=the diameter of the inscribed circle/the diameter of the circumscribed circle×100 (1);

and

wherein the fiber-reinforced thermoplastic resin filament has a flexural stiffness of 1 N·m2 or less.