JPH0153380B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sheet for a molded base material using alloy fibers having a shape memory effect. The purpose of the present invention is to provide a sheet for use as a molding base material that is easy to handle, transport, and easily mold by restoring a sheet material that has been embossed into a desired shape to memorize the shape, and then returns to its original shape when used. It is something to do.

Conventionally, sheet materials for molding include synthetic fibers, inorganic fibers, non-woven fabrics made of fiber webs with heat-fusible low-melting fibers added thereto, or laminated sheets of these non-woven fabrics with resin films, woven fabrics, nets, etc. A sheet material impregnated with a thermoplastic resin or a thermosetting resin as required is used as a base material. When molding such a sheet material, a sheet material cut to a predetermined size is pressurized and heated using male and female molds to mold it into a desired shape to obtain a molded product together with a resin cure, or a low melting point fiber is formed by heating. Molded products are made by softening or melting and then press molding. However, the former is a batch system, has low productivity, requires a large number of molds, and has the disadvantage of not being able to obtain molded products of uniform quality due to uneven resin density and uneven fiber density. .

Furthermore, since the latter lacks elasticity, deep-bottom molded products tend to wrinkle easily and cannot be molded into complex shapes. In addition, since molding is done by heat fusion, there is a drawback that it tends to stick to the mold and has poor workability.
In any case, the resulting molded product had the problem of becoming dense and flat due to the application of high heat and pressure.

The object of the present invention is to provide a sheet for a molded base material for obtaining a molded product that improves the above-mentioned conventional drawbacks. A non-woven fabric sheet material is formed using this material, and the sheet material is memorized by applying stress to a desired shape in advance at a temperature above the martensitic transformation point.The sheet material returns to its original memorized shape by simply heating it during use. The object of the present invention is to obtain a sheet for a molded base material that has excellent bulkiness and texture that cannot be obtained with conventional nonwoven fabric sheet materials, and is also easy to mold, handle, transport, and store.

The shape memory alloy fibers used in the present invention include:
Ti−Ni, Cu−Zn−Al, Cu−Ni−Al, Cu−Zn−
Fibers or fibrous materials such as Sn, Cu-Zn-Si, etc. can be used. In addition to these shape memory alloy fibers, polyester, polyamide, aromatic polyamide, polypropylene, polyester, vinyldene, polyurethane, phenol, polyfluoroethylene, glass fiber, carbon fiber, rock fiber,
Chemical fibers such as metal fibers, natural fibers such as wool, cotton, linen, coconut, or a mixture of these fibers may be used.

Formation of a sheet for a molded base material using such fibers involves forming a web-shaped fiber aggregate using a web forming machine such as a garnet machine or a fiber opening machine, and then applying physical bonding treatment using needle punching, stitch bonding, acrylic, or epoxy. , urethane, NBR,
SBR, vinyl chloride, ethylene-vinyl acetate,
Emulsion of phenol, melamine, etc., latex, aqueous solution or solvent solution type adhesive, chemical bonding treatment with polyethylene, polyamide, polyester resin powder, or using low melting point fiber as adhesive fiber between shape memory alloy fibers, and A sheet for a molded base material can be formed by a bonding process such as making the shape memory alloy fibers shape memory in a crimped state in advance, causing the crimps to develop by heating, and entangling the accumulated fibers in a felt shape.

The shape memory alloy fibers used are short or long fibers with a thickness of 100 μm or less.

One embodiment of the present invention will be described in detail below.

Example 1 Ti-Ni shape memory alloy short fibers with a diameter of 10μ (Ti55.5
Using a mixed fiber of 60% (weight%) and 40% polypropylene fiber with a thickness of 3 denier, the fabric weight was determined using a fiber opening machine.
A web-like fiber aggregate of 500 g/m ² was formed, and the fibers of the fiber aggregate were bonded together by needle punching and impregnation or spraying with NBR latex to produce a mat-like sheet for a molded base material. In order to mold an automobile floor mat using this molding base sheet, a mold 1 is prepared as shown in FIG.
Insert the molded base material sheet 2 into a and 1b and press at a temperature higher than the martensitic transformation point (30°C or higher) to apply external stress to the shape memory alloy fibers to cause them to plastically deform and memorize their shape. , an automobile floor mat 3 is formed as shown in FIG. It is preferable that a resin binder be applied to the surface of the molded automobile floor mat by impregnation or spraying.

When shipping the product, such floor mats can be shipped in a sheet state 4 by pressing at a temperature below the martensitic transformation point (30°C or below), as shown in Figure 3, so they are not bulky and can be handled easily.
It is easy to transport and restores the original shape of the floor mat 3 when heated before use. The above-mentioned automotive floor mats also had an excellent static electricity removal effect.

Example 2 Cu-Zn-Si with a diameter of 20μ [Cu65.9%, Zn32.6%,
Si1.5% (weight%)] Fabric weight 130g/Mixed fibers of 70% shape memory alloy fibers and 30% polypropylene fibers of 3 denier x 51 mm were formed using a garnet machine.
m ² web using Arachne machine, gauge 13/
Stitch bonding was performed under the conditions of 25.2 mm and 3 mm of stitches, and the fibers were further bonded with SBR latex to obtain sheet 5 for molded base material. This is carried out using a press machine equipped with mask molds 6a and 6b shown in FIG. 4 at a temperature above the martensitic transformation point (-4
℃ or higher) at room temperature to form a mask shape and memorize the shape. When such a product is shipped, it is formed into a sheet again at a temperature below the martensitic transformation point, and when used, it is heated to restore the original mask shape and can be cut and used. Further, a brassiere cup can also be easily formed in the same manner as described above.

Example 3 Mixed fibers of 65% Ti-Ni (Ti 55.5% by weight) shape memory alloy fibers with a diameter of 6 μm and 35% polyester fibers 6d ¹ × 51 mm were made into a fabric with a fabric weight of 150 g/
After forming a sheet-like fiber aggregate of 2 m ² and appropriately entangling the fibers with each other using a needle punch, an acrylic acid ester resin emulsion was spread on the front and back surfaces of the web (resin solid content coverage: 15 g/m ² on one side). A bulky batting was formed. This batting was stored at a temperature above the martensitic transformation point (30° C. or above) to retain its bulky shape, and then compressed at a temperature below the martensitic transformation point to form a flat sheet.
Conventional batting has a low apparent density and a high porosity, so it is usually expensive to transport and has disadvantages such as inconvenience in handling, but the batting of the present invention can be transported as a flat sheet. When used, it can be restored to its original bulky sheet by heating above the martensitic transformation point, making it extremely easy to handle and transport.

It should be noted that the shape memory alloy fibers used in the above examples can be appropriately selected and used according to workability by preparing alloy fibers with different martensitic transformations with different composition ratios of alloy components. can.

In the present invention, since the sheet for the molding base material is constructed using shape memory alloy fibers as described above, external stress is applied in advance at a temperature equal to or higher than the martensitic transformation point in accordance with the mold to obtain the desired molded product. If its shape is memorized and it is usually kept in a sheet form for convenient handling and transportation, it can be easily restored to its original shape by simply heating it during use.
It is extremely convenient and efficient to handle and transport, and it does not take up much space as a molded product.
It also requires minimal storage space and can be used for a variety of purposes. In addition, since the obtained molded product is not pressurized at high temperature as in the conventional method, the invention has various effects such as being able to obtain a molded product that is bulky and has an excellent texture, and does not cause wrinkles even when deep drawing is performed. It is.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the molded state of a molded substrate sheet according to an embodiment of the present invention, FIG. 2 is a perspective view of an automobile floor mat obtained by the same molding process, and FIG. FIG. 4 is a side view showing the deformation into the sheet state and the state of restoration into the molded product, and FIG. 4 is a sectional view of the molding apparatus showing another embodiment. 1a, 1b, 6a, 6b...mold, 2, 5...
Sheet for molded base material, 3... Automobile floor mat, 4... Sheet condition.

Claims (1)

[Scope of Claims] 1. A sheet for a molded substrate, characterized in that it is formed by physically and chemically bonding a fiber aggregate formed of shape memory alloy fibers. 2. Chemical fibers containing at least 5% fiber aggregate;
Alternatively, the molded substrate sheet according to claim 1, which is formed by containing natural fibers or chemical fibers and natural fibers.