Patent Application
20210129506
The present invention relates to a phosphorescent thermoplastic composite layered structure, and more particularly relates to a phosphorescent thermoplastic composite layered structure that may increase productivity, be reused, and improve structural toughness compared to those of a conventional phosphorescent thermosetting composite layered structure.
A conventional phosphorescent thermosetting composite layered structure (the prepreg) comprises a phosphorescent thermosetting resin (the matrix) and an oriented continuous fibrous reinforcement (the fibers). The thermosetting resin is composed of a thermosetting polymer and a phosphorescent compound. Layers of thermosetting prepregs are then layered following a sequence of fiber orientation and then subsequently heated and pressurized. During the thermosetting step, the molecular weight of the thermosetting resin increases and chemical bridges might form between individual polymer chains to generate a network structure transforming the polymer from a viscous liquid to an elastic solid. The thermosetting resin might be an epoxy resin, a phenol resin, a polyester resin, or any resin that can go through an irreversible cross-linking reaction to create a solid. Following the cross-linking reaction, the thermosetting resin becomes intractable (cannot be re-melted) and inert to most solvents, preventing subsequent reprocessing.
The phosphorescent material can absorb and store an excitation light source having a wavelength between 200 and 700 nanometers (nm). When the excitation light source stops providing light energy, the phosphorescent material can gradually release the stored energy in the form of light, and the process of releasing the light can last for several hours. Then the phosphorescent material has a temporary light-emitting effect. The phosphorescent material might include a sulfide, an aluminate, a silicate, etc. The reinforcing fiber is used as a reinforcing material for the conventional phosphorescent thermosetting composite layered structure to increase the structural strength of the conventional phosphorescent thermosetting composite layered structure.
To manufacture the conventional phosphorescent thermosetting composite layered structure, firstly, a thermosetting resin, a phosphorescent material, an additive, a curing agent, and an accelerator are uniformly mixed to form a colloid. Then the colloid is uniformly applied to the reinforcing fibers to form a prepreg. Layers of prepreg are then stacked following a fiber orientation sequence. The resulting structure (the pre-form) is then placed in a heated mold, and the temperature and pressure are combined at the same time to allow the colloid to permeate into the space between the reinforcing fibers and to cross-link to create a solid structure. In another process, the prepreg can be partially cured to a so-called beta-stage where cross-linking reactions are allowed to start to increase the viscosity of the thermosetting resin, but interrupted before full cure is occurring. The beta-stage prepreg is then cooled, trimmed, and protected by a release paper layer. Finally, according to the shape requirement of the product, the type of the polymer, and the type of the fiber, etc., for the hot-press forming process of the prepreg, the time required is between 10 and 60 minutes, and the processing temperature is between 120 and 180° C.
The conventional phosphorescent thermosetting composite layered structure has the effects of light storage and light emission, but in the manufacturing process, in order to avoid the curing of raw materials such as resin and prepreg (semi-finished products) before processing, the raw materials are usually stored at low temperature (<−15° C.), the storage conditions are quite strict and the cost required for production is increased. Furthermore, since the prepreg matrix is viscous, it is necessary to package the prepreg with a release paper in order to avoid the prepreg to stick to itself or to surrounding objects, and this will increase the time and cost required for production, and lack economic benefits. Additionally, due to the materials properties of thermosetting, the conventional phosphorescent thermosetting composite layered structure cannot be repeatedly processed after heat curing, and this relatively lacks value for reuse. In addition, the conventional phosphorescent thermosetting composite layered structure after hot pressing has an insufficient inter-laminar fracture toughness value (0.1 to 1 kJ/m2).
To overcome the shortcomings, the present invention provides a phosphorescent thermoplastic composite layered structure to mitigate or obviate the aforementioned problems.
The main objective of the present invention is to provide a phosphorescent thermoplastic composite layered structure and a method of manufacturing said phosphorescent thermoplastic composite layered structure that may increase productivity, be reused, and improve structural toughness.
The phosphorescent thermoplastic composite layered structure in accordance with the present invention has at least one layered element. Each one of the at least one layered element has a thermoplastic polymer (matrix) and an oriented continuous fibrous reinforcement (fibers) combined with the thermoplastic polymer (matrix). Furthermore, the thermoplastic polymer (matrix) contains a phosphorescent compound uniformly combined with the thermoplastic polymer. The oriented continuous fibrous reinforcement (fibers) is combined with the thermoplastic polymer (matrix) to form a phosphorescent prepreg, and layers of prepregs are subsequently consolidated in a shaped object by pressing and heating.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.
With reference to
Preferably, the polymer matrix is further provided with a plasticizer and other additives, wherein the plasticizer enhances the mixing of the thermoplastic polymer 20 and the phosphorescent compound 30 by lowering the resin viscosity. Then the thermoplastic polymer 20 and the multiple particles of the phosphorescent compound 30 can be combined with the oriented continuous fibrous reinforcement (fibers) 40. The additives may be an antioxidant (increasing the oxidation resistance of the polymer matrix), a dispersing agent (uniformly dispersing the phosphorescent compound 30 in the polymer matrix), a coupling agent (enhancing the bonding property between the polymer matrix and the oriented continuous fibrous reinforcement (fibers) 40), or a combination of them.
With reference to
The oriented continuous fibrous reinforcement (fibers) 40 has multiple continuous fibers. Preferably, the continuous fibers comprise carbon fibers, glass fibers, mineral fibers, and polymer fibers, etc. The appearance of the continuous fibers may be short fibers, long fibers, continuous fibers, or woven fibers, etc. In manufacture, the phosphorescent thermoplastic resin is uniformly applied to the continuous fibers, and the phosphorescent thermoplastic resin is infused into the space between the continuous fibers by increasing temperature and pressure.
The phosphorescent thermoplastic resin is melted above its glass transition temperature (for an amorphous polymer) or its melting point temperature (for a semi-crystalline polymer), and at a temperature at which the polymer viscosity is low enough for viscous flow to occur in order to uniformly and fully impregnate the fibrous reinforcement. After cooling to a temperature lower than the polymer glass transition temperature (for an amorphous polymer) or the polymer crystallization point (for a semi-crystalline polymer), a prepreg of the phosphorescent thermoplastic composite layered structure is formed, and the foregoing operation is the second operating step in the manufacturing process as shown in
Furthermore, with reference to
With the above-mentioned technical features and structural relationships, the phosphorescent thermoplastic composite layered structure of the present invention uses the thermoplastic polymer 20 as one of the raw materials of the polymer matrix, so that the prepreg can be stored at room temperature indefinitely. Furthermore, the surface of the prepreg that is made from the thermoplastic polymer 20 is dry and devoid of tackiness and does not cause sticking. Therefore, it is not necessary to use a release paper for packaging during the production process, which not only shortens the production time but also reduces the cost.
Additionally, due to the material properties of the thermoplastic polymer 20, the phosphorescent thermoplastic composite layered structure of the present invention, after the step of hot press forming, can be repeatedly reprocessed by reheating, and has the value of reuse and conforms to the trend of environmental protection. Further, the time required for hot-press forming (less than 5 minutes) is shorter than the conventional thermosetting resin (10 to 60 minutes), and can effectively improve the production efficiency.
In addition, the phosphorescent thermoplastic composite layered structure made of the thermoplastic polymer 20 has an inter-laminar fracture toughness value of 1 to 10 kJ/m2, higher than the toughness value of the conventional phosphorescent thermosetting composite layered structure (0-1 kJ/m2), the tensile strength is greater than 300 MPa, and the tensile modulus is greater than 17 GPa with woven glass fabric at fiber volume fraction: 50%. The continuous illuminating time is more than 12 hours. Therefore, the present invention can effectively improve the structural toughness of the phosphorescent thermoplastic composite layered structure, thereby increasing the application range, thereby providing an improvement in production efficiency, re-use, and improvement of structural toughness.
Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and features of the invention, the disclosure is illustrative only. Changes may be made in the details, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.
