Emulsion type sizing agent for carbon fiber as well as preparation method and application of emulsion type sizing agent

Abstract

The invention discloses an emulsion type sizing agent for a carbon fiber as well as a preparation method and application of the emulsion type sizing agent. The sizing agent contains 2-40 percent of epoxy resin, 0-97 percent of water, 0.5-14 percent of surfactant, 0.3-12.5 percent of cardanol, 0.1-1.5 percent of formaldehyde and 0.1-2.0 percent of inorganic ammonium salts. The emulsion type sizing agent contains the cardanol and the formaldehyde as toughening and modifying agents, so that when the carbon fiber sized by using the emulsion type sizing agent for the carbon fiber is compounded with an epoxide resin matrix taking polyamine as a curing agent to form a composite material, the interlaminar shear strength is improved by over 30 percent and the carbon fiber composite material is enabled to have higher integral performance. The emulsion type sizing agent contains the inorganic ammonium salts, so that the storage stability of the sizing agent is greatly improved and the phenomena of demixing and non-uniformity of concentration are avoided. According to the emulsion type sizing agent disclosed by the invention, the phenomena of demixing and emulsion breaking in the use process of the sizing agent are avoided. After the carbon fiber sized by the sizing agent disclosed by the invention is stored at normal temperature for five years, the mass percentage of the sizing agent on the surface of the carbon fiber is unchanged.

Description

technical field [0001] The invention belongs to the field of carbon fiber production, and in particular relates to an emulsion-type carbon fiber sizing agent and a preparation method and application thereof. Background technique [0002] In carbon fiber reinforced composite materials, a sizing agent is used as a transition layer between the reinforced carbon fiber and the matrix resin. The sizing agent can well connect the carbon fiber and the matrix resin, making the carbon fiber reinforced composite material a Overall, with strong overall performance. [0003] Patent CN1318686C discloses a sizing agent for carbon fibers, the sizing agent for carbon fibers contains, (A) a compound having at least one epoxy group in the molecule, (B) an anionic surfactant with ammonium ions as counter ions, ( C) Nonionic surfactants. [0004] However, the composite material made of carbon fiber after sizing with the above-mentioned carbon fiber sizing agent has a brittle effect after curin...

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Problems solved by technology

[0004] However, the composite material made of carbon fiber after sizing with the above-mentioned carbon fiber sizing agent has a brittle effect after curing as the epoxy resin contained in the sizing agent of the transitional connection layer, which affects the effective combination of carbon fiber and matrix resin. The interlaminar shear strength of the carbon fiber epoxy resin matrix composite material is small, which has a great adverse effect on the overall performance of the carbon fiber composite material.

Moreover, the storage and use stability of the above-mentioned carbon fiber sizing agent is relatively poor. During storage and use, emulsion stratification, uneven distribution of emulsion concentration, and even premature demulsification, flocculation, agglomeration, etc., occur in the sizing agent. Layers, sinking, turbidity, etc., carbon fiber sizing cannot be carried out, and rapid stirring cannot be carried out during use and transportation, which brings great inconvenience to carbon fiber production and affects the overall performance of carbon fiber and its composite materials. also have a great adverse effect on

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