The present invention relates to method of manufacturing an aircraft interior panel (20) comprising a core (22) sandwiched between first and second skins (24,26), wherein both of the first and second skins are formed from natural fibres containing non-halogenated fire-retardant and set within an inorganic thermoset resin, thereby forming a fire-resistant sustainable aircraft interior panel. The method comprises impregnating the natural fibres with non-halogenated fire retardant and an inorganic thermoset resin, and laying up the resin-impregnated natural fibres to sandwich the core (22). This stack is then cured by raising the temperature of the stack sufficient to initiate curing but without reaching the boiling point of water in the stack, holding the stack at that first temperature before raising the temperature again to reach the boiling point of water in the stack, before cooling the stack.

The method includes the preparation of the preimpregnated product, its pressing, hardening and charring and is characterised in that after preparing the preimpregnated product, this undergoes a heat treatment between 70 and 1100 deg. C, is embedded with an inert substance that comprises a charge and a polymeric binder in a quantity greater than the volume of the voids of the single-layer yarn which is calculated by means of the formula [1], where m_n is the mass of the inert substance, d_n is the density of the inert substance, a is the length of the preimpregnated product, b is the width of the preimpregnated product, h is the thickness of the preimpregnated product, m_pr is the mass of the preimpregnated product, and d_fib is the density of the fibre, and is heated between 160 deg. C and 200 deg. C, a pressure of between 1 and 5 MPa being applied simultaneously. The method is useful for manufacturing composite materials with a matrix which contains carbon and variable porosity, for example, current collectors of fuel cells with electrode aggregates, porous electrochemical electrodes or filtration elements.$${\text{m}}_{\text{n}}{\text{=d}}_{\text{n}}\text{. (a.b.h -}\frac{{\text{m}}_{\text{pr}}}{{\text{d}}_{\text{fib}}}\text{)}$$

To provide an epoxy resin composition suitable as a matrix resin for fiber reinforcement, and a yarn prepreg suitable in unwindability, excellent in higher processability due to drapability, high in the tensile strength of the epoxy resin composition after curing, and high in efficiency of the strength of reinforcing fibers.

A yarn prepreg, satisfying the following formulae (1) to (3):$$\begin{array}{c}\begin{array}{c}\begin{array}{}\text{(1)}\text{50 ≤ Wf ≤ 80}\end{array}\\ \begin{array}{}\text{(2)}\text{20,000 ≤ F ≤ 100,000}\end{array}\\ \begin{array}{}\text{(3)}\text{F/8,000 ≤ d ≤ F/2,400}\end{array}\end{array}\end{array}$$ where Wf is the content by weight of the fiber bundle (%), F is the number of filaments in the fiber bundle and d is the width of the prepreg (mm).

An epoxy resin composition for a fiber reinforced composite material, comprising at least the following components [A], [B] and [C]:

[A]:

An epoxy resin mixture containing two or more epoxy resins, in such a manner that 100 weight parts of the epoxy resin mixture contains 40 to 79 parts of a monofunctional or bifunctional epoxy resin and 21 to 60 parts of a trifunctional or higher functional epoxy resin and that the epoxy resin mixture is 210 to 370 in epoxy equivalent weight

[B]:

Fine particles containing a rubber ingredient and insoluble in the epoxy resins

[C]:

A curing agent

The present invention relates to a prepreg, a preformed prepreg, a fired prepreg, a redensified prepreg and methods of constructing these materials. Further, the invention pertains to a fire-safe panel comprising a ceramic fiber-reinforced material, a fire-safe fixture comprising a ceramic fiber-reinforced material, a laminated honeycomb material containing a fiber-reinforced ceramic material, or composites constructed from such materials.