Shindo noncrimp fabrics (NCFs) have been used for various products in the aerospace, marine, civil construction, and repair and reinforcement fields.
There are four features that characterize this new NCF-Resinply:
1. Design flexibility. 2. Grant drapability. 3. Labor economy during the molding process. 4. Stable molding quality
In terms of design flexibility, the product can be adapted to various specifications regarding material selection, layered structure, and stitch design. Also, a continuous fabric can be produced in machine direction (0°), transverse direction (90°), and diagonal direction (+30°–90°/ −30°–90°) that can be customized by the user.
Regarding the drape properties, the deformation characteristics of the material are facilitated by fabric-fiber reinforcement, appropriate resin selection, areal weight design, the use of a layered composition, and a suitable stitch-condition design. On the other hand, the product can also be adjusted as a material with shape stability against the load. The S–S diagram which shows the tensile properties of the NCF-Resinply material, demonstrates that the product exhibits drape properties and deformation characteristics when used as an NCF.
Furthermore, the material can be adjusted to an NCF prepreg for difficult deformations.
The time and labor economy of the molding process has been improved by making the insertion and lamination of a resin layer into the fabric layer unnecessary, as is the case for general NCFs. End users can make the molding by just laminating the NCF-Resinply on the mold after cutting the fabric followed by heating/pressurization. Because of this simplicity, the laminating time can be shortened by 40%–60% as compared to that required for unidirectional materials and general NCFs without using resin films.
With respect to stable molding quality, NCF-Resinply is a material in which NCF (as reinforcing fibers) and resin sheets are integrated by stitch bonding. Therefore, it is possible to increase the fiber-orientation accuracy by reducing disturbances in the reinforcing-fiber orientation to a minimum due to resin flow after heating/pressurization. Because of this, the end users can realize a molding that has various physical properties, including strength and rigidity, in accordance with the required design.
NCF-Resinply has many design possibilities that meet the customer’s needs. These include the following:
- Fiber selection :carbon fiber, glass fiber, aramid fiber, etc.
- Thermoplastic resin selection: types of resin available are polyamide (PA), polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), and so on. Form of the resin: nonwoven fabric or film.
- Areal weight: NCF layer areal weight: 75–300 g/m2. Thermoplastic resin areal weight: total 20–400 g/m2
- Layered structure: NCF orientation angle: +30°–90°, −30°–90°, 0°. The thermoplastic resin layer is insertable within any layer (but if a reinforcing fiber is inserted at 0° into the NCF, the thermoplastic resin layer will not be inserted into the upper layer of the 0° sheet).
- Stitch selection: PET, PA, polyetherimide (PEI), glass fiber (GF), and so on.
- Stitch design: the stitch pattern, stitch length, and stitch pitch can be customized in accordance with customer requests and applications.
The new material has been studied for the continuous production of moldings with the same cross-sectional shape, but it can also be used for molding three-dimensional curved surface shapes.
Moreover, the material can be used in various fields because it has several desirable physical properties including mechanical stability, impact resistance, low water-absorption tendency, and heat resistance.
The reinforcing fibers of the NCF-Resinply material can be configured to a state of continuous fibers; therefore, it is possible to achieve a high strength development, speed up the molded-product cycle, and increase the toughness of the molded product by using a thermoplastic resin such that the resin layer will serve as a matrix. For this reason, it is expected that the material will be used in the aerospace and automotive fields, which require materials with such physical properties (including the parts for which a cost balance is required as well). In addition, considering the high corrosion resistance of NCFs, the product has also been studied as an alternative for materials made of metals and concrete, which suffer from corrosion. There is concern about durability, or strength and rigidity is missing due to it composed only of resin in the fields of tubular structure is embed in the ground such as a drain pipe.
INTERVIEW OF HIDETOSHI KASAKAWA, DEVELOPMENT TEAM LEADER
How did NCF Resinply start?
At the beginning, we were trying to develop a thermoplastic prepreg based on NCF (non-crimp fabric). But NCF has layers with oriented reinforcing fibres, so that it becomes warped and its drapeability deteriorates when it is impregnated with resin. This is how the idea of NCF Resinply came up.
What are the advantages and characteristics of NCF Resinply?
By inserting a thermoplastic resin layer into NCF as a matrix and leaving it unimpregnated, drapeability can be ensured. The layer can be impregnated with the resin by heating and pressing the material as it is, and high-strength, high-rigidity FRP parts can be produced.
By optimizing material specifications such as stitching conditions and material selection, as well as moulding conditions, it is possible to prevent the flow of reinforced fibres during the resin impregnation step. The performance required for the products can be easily achieved because the fibre orientation angle can be maintained.
What are NCF Resinply’s prospects for the future?
As the market for the composite materials industry will grow globally, I hope that NCF Resinply will be popularized as one of the materials and options allowing the selection of suitable materials.
The FRP product manufacturing process from the base material to the final product will
be simplified as much as possible through innovation in the base material design and the moulding technology.
INTERVIEW OF YOSHINOBU TSUCHIYA, DEVELOPMENT TEAM MANAGER
What are the application sectors for this product?
Since thermoplastic resins offer excellent toughness, we are considering expansion into fields that need improved interlayer strength and impact resistance. In addition, this material can be recycled, and does not have to be scrapped after a single use. We think that it is possible to use it several times through recycling. Since NCF Resinply is impregnated during the moulding process, there is little resin deterioration and it is suitable for recycling.
What do you expect from this new material?
As its qualities become better known, we expect its use to grow globally.
Companies: SHINDO Global Site
Technologies: Compression Moulding