JLQR OIL AGENT
The oil agent or spinning finish for polyacrylonitrile (PAN) carbon fiber precursor is an essential key additive in the production of carbon fiber. The oil agent should be flame retardant and prevent its coated PAN monofilament from melting, bonding or merging in the pre-oxidation process, without fluffing and yarn breakage. The oil agent not only directly affects the stable production and the quality of PAN carbon fiber precursor, but also has a significant impact on the quality of the carbon fiber subsequently carbonized from PAN carbon fiber precursor. The oil agent endows PAN carbon fiber precursor with softness, antistatic and lubrication, prevents friction and wear between monofilament surfaces, reduces the friction between fiber tow and drive roller, and reduces fluffing.
The oil agent contained silicone used by China's PAN carbon fiber precursor production enterprises depends on imports, which belongs to China's "stuck neck" key technology. The price of the oil agent imported from Japan is as high as 400000 yuan / ton, which seriously restricts the improvement of carbon fiber quality and production cost in China. Domestic universities and enterprises usually utilize the reverse analysis of international brand oil agents to imitate the composition of imported oil agents. The main components of compound oil agents generally consist of amino modified silicone oil, polyether modified silicone oil and epoxy modified silicone oil (as shown in Figure 1).
Amino modified silicone oil is easy to react with epoxy modified silicone oil in the compounding oil agent emulsion, resulting in the phase separation and demulsification of various components in oil agent emulsion. Because the components of compound oil agent have different affinity or adhesion to PAN carbon fiber precursor, the composition of the oil agent adsorbed and coated onto the surface of PAN precursor fiber and that of remained composition of the oil agent in oil tank keep changing during the process of oil agent coating on PAN carbon fiber precursor fiber, leading to the discontinuous and unstable rate of oil agent coating on the surface of PAN carbon fiber precursor. The homogeneity of the oil agent composition coated on the PAN carbon fiber precursor was not consistent, which further affect the continuous stability of carbon fiber produced from subsequently carbonization of PAN carbon fiber precursor. At the same time, when PAN carbon fiber precursor coated by oil agent is drying at high temperature, the cross-linking reaction between amino modified silicone oil and epoxy modified silicone oil in the compound oil agent is rapid, resulting in a sharp increase in the molecular weight of the compound oil agent and roll sticking.
Jilin Qianren Innovative Material Co., Ltd. (hereinafter referred to as JLQR) undertakes the task of tackling the " stuck neck " technology of key additives applied in the carbon fiber industry chain from Jilin Province (city), and independently develops a series of oil agents containing silicone. The product technology innovation from JLQR lies in the integrated self-assembly and self-emulsification design of amino, epoxy and polyether silicone oil, without external emulsifiers, defoamers, antistatic agents and other additives. At the same time, the epoxy resin is embedded in the molecular chain segment of the oil agent to greatly reduce its silicon content (as shown in Fig. 2). On the one hand, the oil agent of JLQR avoids phase separation and cross-linking reaction in the storage process and spinning oiling process, thus leading to solves the technical difficulties such as poor storage stability, low thermal stability, roll sticking of the oil agent ， fluffing and poor bundling of PAN carbon fiber precursor coated from oil agent. On the other hand, in the carbonization process, the oil agent has low pollution to carbon fiber and carbonization equipment because of low silicon content in the oil agent of JLQR. At the same time, the oil agents of JLQR ensures its stable composition both in oil tank and on the surface of carbon fiber precursor during the continuous spinning production of PAN carbon fiber precursor through multi-component integrated, self-assembly and self-emulsification design of its oil agent.
The oil agent designed and produced by JLQR is conducive to the pre oxidation of PAN carbon fiber precursor coated by its oil agent. Because the hydrophobic fat chain of oil agent coated on the surface of PAN carbon fiber precursor is easy to trigger the pre-oxidation reaction at a lower temperature to generate porous surface, and air is easy to penetrate and diffuse into PAN carbon fiber precursor through porous oil agent’s coating to trigger oxidative reaction. Therefore, the pre-oxidation speed of PAN carbon fiber precursor coated with oil agent of JLQR is faster than that of PAN carbon fiber precursor coated with Japanese Takemoto Co., Ltd. (as shown in Figure 3-5). The properties of PAN carbon fiber precursor produced from the oil agent of JLQR and subsequently carbonized carbon fiber meet or exceed those of similar products produced with the oil agents of the international enterprise (as shown in table 1-3).
图 2 吉林乾仁新材料-太阳√集团城官网1407有限公司自乳化含硅油剂一体化设计
图5 使用吉林乾仁新材料-太阳√集团城官网1407有限公司油剂生产的PAN 原丝（***左边一束）对比使用日本竹本油剂生产的PAN原丝在吉林国兴碳纤维生产线上进行预氧化和碳化过程
表2 吉林乾仁新材料-太阳√集团城官网1407有限公司油剂同国际油剂上油后PAN 碳纤维原丝性能对比