CN-121992598-A - Large-tow carbon fiber sizing method and device

CN121992598ACN 121992598 ACN121992598 ACN 121992598ACN-121992598-A

Abstract

The invention discloses a large-tow carbon fiber sizing method and device, and relates to the technical field of carbon fibers. The large-tow carbon fibers are sequentially processed by a first-stage dynamic tension control unit, an ultrasonic auxiliary sizing tank unit, a second-stage dynamic tension control unit, a quantitative extrusion unit and a pre-drying and winding unit, a dynamic tension process of low tension infiltration-high tension distribution is adopted, macroscopic distribution of sizing agent on the cross section of the tow is actively regulated and controlled in a mechanical mode and is complementary with ultrasonic microcosmic action, air barriers in the large tow can be effectively broken through ultrasonic cavitation effect, sizing agent is ensured to directly reach the core part of the tow, and the phenomenon of dry core is eliminated. The sizing method provided by the invention can obviously improve the sizing uniformity of the large-tow carbon fibers, is beneficial to improving the interfacial property of the carbon fibers and reduces the fuzzing amount.

Inventors

CHEN CHEN
LIU DONG
LI GUO
Fan Jinruo
LIU XIUQING

Assignees

中复神鹰碳纤维连云港有限公司

Dates

Publication Date: 20260508
Application Date: 20260317

Claims (10)

1. The large-tow carbon fiber sizing method is characterized in that the adopted large-tow carbon fiber sizing device comprises a first-stage dynamic tension control unit, an ultrasonic-assisted sizing tank unit, a second-stage dynamic tension control unit, a quantitative extrusion unit and a pre-drying and winding unit which are sequentially arranged along the advancing direction of a carbon fiber tow; the method comprises the following steps: Pre-relaxation and preliminary infiltration, namely regulating the tension of the large-tow carbon fibers entering the ultrasonic-assisted sizing tank unit to be T1 through the first-stage dynamic tension control unit; Ultrasonic intensified penetration, namely immersing the large-tow carbon fibers in a sizing agent in the ultrasonic auxiliary sizing tank unit, and simultaneously carrying out ultrasonic treatment; Dynamic tension assisted redistribution, namely after the large tow carbon fibers leave the ultrasonic assisted sizing groove unit, utilizing the second-stage dynamic tension control unit to lift the tension to T2, and keeping the tension of the T2 to run; And quantitatively controlling and solidifying, namely entering the quantitative extrusion unit after passing through the second-stage dynamic tension control unit, regulating and controlling the sizing amount through extrusion, and entering the pre-drying and rolling unit after passing through the quantitative extrusion unit to solidify the sizing agent.
2. The large tow carbon fiber sizing process of claim 1, wherein T1 ranges from 25cN to 35cN and T2 ranges from 90cN to 110cN; And/or the specification of the large-tow carbon fiber is 48K-96K.
3. The large tow carbon fiber sizing method according to claim 1, wherein the quantitative extrusion unit comprises a quantitative extrusion roller pair, and excess sizing is removed by extrusion to control the sizing rate to be 0.8wt% to 1.5wt%.
4. A method of sizing large tow carbon fibers according to claim 1 or3, wherein the T2 tension is maintained for 1m-3m before entering the quantitative extrusion unit.
5. The method for sizing large-strand carbon fibers according to claim 1, wherein the ultrasonic-assisted sizing tank unit comprises a sizing tank for containing sizing agent, and ultrasonic transducers are arranged on both sides and the bottom of the tank body of the sizing tank.
6. The method for sizing large-strand carbon fibers according to claim 5, wherein the vibration frequency of the ultrasonic transducer is controlled to be 15kHz-100kHz, the power density is 0.2W/cm 2 -1.0W/cm 2 , and the ultrasonic time is 1s-10s.
7. The method of sizing large tow carbon fibers of claim 1, wherein the first stage dynamic tension control unit comprises a first godet set and a first stage dynamic tension controller by which tension applied to the carbon fibers by the first godet set is controlled.
8. The method of sizing large tow carbon fibers according to claim 1 or 7, wherein the first stage dynamic tension control unit and the second stage dynamic tension control unit each employ a closed loop controlled servo motor driven guide roller system.
9. The method for sizing large-tow carbon fibers according to claim 1, wherein the drying temperature is controlled to be 110-130 ℃ and the drying time is controlled to be 30-180 s during the treatment of the pre-drying and winding unit.
10. An apparatus for carrying out the large tow carbon fiber sizing method according to any one of claims 1 to 9, characterized by comprising a first stage dynamic tension control unit, an ultrasonic-assisted sizing tank unit, a second stage dynamic tension control unit, a quantitative extrusion unit and a pre-drying and winding unit which are sequentially arranged along the advancing direction of the carbon fiber tows; the first-stage dynamic tension control unit and the second-stage dynamic tension control unit both comprise a godet set and a controller for controlling the godet set to apply tension; the ultrasonic auxiliary sizing tank unit comprises a sizing tank for containing sizing agent, and an ultrasonic transducer is arranged on a tank body of the sizing tank; the quantitative extrusion unit comprises a quantitative extrusion roller pair, and excess slurry is removed through extrusion so as to control the sizing rate; the pre-drying and rolling unit comprises a pre-drying oven.

Description

Large-tow carbon fiber sizing method and device Technical Field The invention relates to the technical field of carbon fibers, in particular to a large-tow carbon fiber sizing method and device. Background In the sizing process of carbon fibers, uniform coating of sizing agents (or called as "sizing agents" and "sizing agents") is important, and the sizing agents directly affect the interfacial bonding performance of the carbon fibers and a resin matrix, the mechanical properties of subsequent composite materials and the amount of filaments in the processing process. In the prior art, the traditional dip-squeeze roll sizing method has good effect on small tows (such as 3K and 12K) of carbon fibers. However, when applied to large tow carbon fibers (48K and above), the following drawbacks exist due to the large number and close arrangement of the filaments inside: (1) The external monofilaments of the filament bundle are easy to contact with and wrap the sizing agent preferentially, and the internal monofilaments are difficult to be effectively permeated by the sizing agent due to capillary action and fluid resistance, so that a dry core phenomenon is formed; (2) The squeeze rollers only can apply pressure to the whole filament bundle, and can not promote the sizing agent to be uniformly distributed in the micro-scale inside the filament bundle, so that the thickness of the sizing agent on the surface of the monofilament is different; (3) The tension applied by the traditional equipment on the whole sizing path is relatively constant, and cannot be dynamically adjusted according to the needs of sizing agent infiltration stages, so that the sizing agent infiltration into the interior is not facilitated. The uneven distribution of sizing agent can lead to the occurrence of interface weak areas of large-tow carbon fibers in the subsequent preparation of composite materials, and the full play of the performances of the large-tow carbon fibers is seriously affected. Therefore, the technical problem of uneven infiltration and coating of the sizing agent of the monofilaments in the large-tow carbon fibers is needed to be solved. In view of this, the present invention has been made. Disclosure of Invention The invention aims to provide a large-tow carbon fiber sizing method and device, and aims to solve the technical problem that sizing agent infiltration and coating of monofilaments in the large-tow carbon fibers are uneven. The invention is realized in the following way: In a first aspect, the invention provides a large-tow carbon fiber sizing method, wherein the large-tow carbon fiber sizing device comprises a first-stage dynamic tension control unit, an ultrasonic-assisted sizing tank unit, a second-stage dynamic tension control unit, a quantitative extrusion unit and a pre-drying and winding unit which are sequentially arranged along the advancing direction of a carbon fiber tow; the method comprises the following steps: Pre-relaxation and preliminary infiltration, namely regulating the tension of the large-tow carbon fibers entering an ultrasonic auxiliary sizing tank unit to be T1 through a first-stage dynamic tension control unit; Ultrasonic intensified penetration, in which large tow carbon fiber is immersed in sizing agent in an ultrasonic auxiliary sizing tank unit and simultaneously subjected to ultrasonic treatment; dynamic tension assisted redistribution, namely after the large tow carbon fibers leave an ultrasonic assisted sizing groove unit, utilizing a second-stage dynamic tension control unit to lift the tension to T2, and keeping the tension of the T2 to run; The quantitative control and solidification process includes the steps of entering a quantitative extrusion unit after passing through a second-stage dynamic tension control unit, regulating and controlling sizing amount through extrusion, and entering a pre-drying and rolling unit after passing through the quantitative extrusion unit to solidify sizing agent. In an alternative embodiment, T1 ranges from 25cN to 35cN, and T2 ranges from 90cN to 110cN; and/or the specification of the large-tow carbon fiber is 48K-96K. In an alternative embodiment, the quantitative pressing unit includes a quantitative pressing roller pair for removing excess slurry by pressing to control the sizing rate to be 0.8wt% to 1.5wt%. In an alternative embodiment, the quantitative extrusion unit is entered after maintaining the tension of T2 for 1m-3 m. In an alternative embodiment, the ultrasonic-assisted sizing tank unit comprises a sizing tank for containing sizing agent, and ultrasonic transducers are arranged on both sides and the bottom of the tank body of the sizing tank. In an alternative embodiment, the ultrasonic transducer is controlled to vibrate at a frequency in the range of 15kHz to 100kHz, a power density of 0.2W/cm 2-1.0W/cm2, and an ultrasonic time of 1s to 10s. In an alternative embodiment, the first stage dynamic tension control unit includes a firs