JP3142078B2 - Fiber reinforced resin molding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an invention for obtaining an excellent deep drawn product by using a knitted fabric made of a high-strength organic synthetic fiber as a reinforcing material for a resin composition. And the purpose is to make deep drawn products,
It is an object of the present invention to provide a molded article having extremely excellent bending strength and impact resistance (particularly, penetration impact resistance). In the present specification, deep drawing is a kind of molding method of a fiber reinforced resin molded product (hereinafter, abbreviated as FPR), and is used for forming a woven or knitted fabric, This method refers to a method of forming an FRP without cutting a non-woven fabric or the like along a form, and preventing the fabric from wrinkling and overlapping.
Method, S-RIM method, autoclave method, back method and the like.

[0002]

2. Description of the Related Art Conventionally, when an FRP having a complicated shape is formed using a formwork having irregularities, a woven fabric, a nonwoven fabric, or the like is cut and formed along the formwork. It is also known that a fiber such as nylon, acrylic, or polyester, which is a general-purpose organic synthetic fiber, is used as a knitted material and used as a reinforcing material to perform deep drawing. However, the conventional method of cutting a woven fabric, a non-woven fabric, or the like, and forming an FRP having a complicated shape along the formwork requires a very complicated FRP forming process, and furthermore, a cut portion of the woven fabric, the non-woven fabric, etc. Are disadvantages in FRP, and deteriorate physical properties such as bending strength and impact resistance. Further, in the case of a knitted fabric using fibers such as nylon, acrylic, and polyester, which are general-purpose organic synthetic fibers, deep drawing can be performed but sufficient FRP physical properties cannot be obtained. This is because fibers such as nylon, acrylic, and polyester, which are general-purpose organic synthetic fibers, have low tensile strength and tensile modulus.

[0003]

If deep drawing can be performed without cutting the fabric, the FRP forming process becomes very simple. In addition, the cutting part is FRP as before.
It does not become a defect inside, and the physical properties such as bending strength and impact resistance do not deteriorate. Further, if the impact resistance of the FRP is high, cracks or whitening hardly occurs on the surface of the FRP when an impact is applied to the FRP, and the quality and appearance of the product are not impaired. Therefore, high rigidity and impact resistance are indispensable conditions not only for outer plates of automobiles, vehicles, ships and the like but also for applications such as pipes and bathtubs. However, in reality, a method of cutting a woven fabric, a nonwoven fabric, or the like, and forming an FRP having a complicated shape along the formwork,
Only knitted fabrics such as nylon, acrylic, and polyester, which are general-purpose organic synthetic fibers, are used. Therefore, the FRP reinforced with a woven or knitted fabric or a nonwoven fabric according to the prior art is insufficient in physical properties such as bending strength and impact resistance, and is used not only for outer plates of automobiles, vehicles, ships, etc. but also for pipes and bathtubs. Could not be used. For these reasons, there has been a demand for a material that can be deep-drawn and exhibit sufficient FRP properties in the field of FRP.
Accordingly, an object of the present invention is to provide a deep drawn molded product having excellent physical properties such as bending strength and impact resistance in a fiber reinforced molded product.

[0004]

Means for Solving the Problems The present inventors have continued research on materials and techniques that can be deep drawn and exhibit sufficient FRP physical properties, and as a result, have a single fiber tensile strength of 100 kg /.
mm ² or more, making a knitted monofilament tensile modulus using a 4000 kg / mm ² or more organic synthetic fibers, if used as a reinforcing material for resins which this knitted fabric deep drawing, the molding of the above conventional methods as well as It has been found that defects on the product can be eliminated and the intended problem can be achieved. That is, the present invention
This is an FRP formed by deep drawing using a knitted fabric made of an organic synthetic fiber having a single fiber tensile strength of 100 kg / mm ² or more and a single fiber tensile elastic modulus of 4000 kg / mm ² or more as a reinforcing material.

[0005] As a result of examining the most suitable organic synthetic fiber for enhancing the bending strength and impact resistance of FRP, we have found that the single fiber tensile strength is 100 kg / mm ² or more and the single fiber tensile elastic modulus is 4000 kg / mm ² or more. It has been found that it is preferable to use organic synthetic fibers such as high-strength polyvinyl alcohol-based fibers, polyarylate fibers, aramid-based fibers, and polyethylene-based fibers that satisfy the above properties. That is, general-purpose organic synthetic fibers having mechanical properties lower than the above-mentioned mechanical properties, such as nylon, acrylic, and polyester fibers, were found to be unfavorable. In addition, as a result of studying inorganic fibers, it was found that when the fibers were knitted, the fibers were damaged or fluffed, and a satisfactory knit was not obtained. Further, the bending strength of the FRP is improved, but the impact resistance is significantly reduced. That is, it was found that inorganic fibers such as carbon fiber and glass fiber are not preferable.

What is important in the present invention is that the cloth as the reinforcing material extends along the irregularities of the molding frame. For this purpose, a knitted fabric is used as a reinforcing material. The type of the knitted fabric includes a warp knitted fabric, a weft knitted fabric, and a circular knitted fabric, but is not particularly limited. In the present invention, the degree of deep drawing is such that the area of the reinforcing material before forming is 1.5 times or more (that is, the surface area of the reinforcing member three-dimensional portion generated by the depression relative to the area of the portion to be depressed by molding is 1.5 times or more) (More than twice) is preferable to be a solid object having a depth of 5 cm or more. In the case of a helmet, the area is about twice and the depth is about 13cm
It is.

[0007] The volume content (hereinafter abbreviated as Vf) of the knitted fabric in FRP is preferably 10% to 80%. More preferably, it is 20% to 70%. Vf is 10
%, The reinforcing effect of FRP is small, and F
The flexural rigidity and impact resistance (especially penetration impact resistance) of RP become extremely poor, and if Vf exceeds 80%, the impregnating property of the resin becomes poor and FRP cannot be formed.

[0008] The FRP of the present invention is characterized in that the reinforcing material can sufficiently conform to the irregularities of the mold by deep drawing, and the usual hand lay-up method, matched die method, resin injection method, resin transfer molding method, and the like. Can also be obtained by using the FRP production method of Examples of the resin used for this purpose include thermosetting resins such as unsaturated polyester resin, epoxy resin, vinyl ester resin, phenol resin, and melamine resin, and polypropylene resin, polyethylene terephthalate resin, polybutylene terephthalate resin, and polycarbonate resin. Thermoplastic resins such as polyacetal resin, polyphenylene sulfide resin, polyamide resin and ABS resin are also used.

[0009]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples. However, the present invention is not limited to this embodiment. The following examples and comparative examples are examples in which the present invention is used to obtain a molded product having a hemispherical curved surface portion having a relatively deep concave portion, that is, a molded product as a so-called helmet. The resins used in the following Examples and Comparative Examples were all based on the following formulations. 《Resin formulation》 ────────────────────────────────── Unsaturated polyester resin (Showa Polymer Co., Ltd. 6709) 80 parts 20 parts (Showa High Polymer Co., Ltd. Polymer 9965) ─ Hardener (Nippon Oil & Fats Co., Ltd., Permec N) 2 parts Same (Cobalt naphthenate) 0.2 parts ────────────────────────── ────────

Example 1: Single fiber strength is 230 kg / m
Filament (1800 denier / 1000 filament) of polyvinyl alcohol (hereinafter abbreviated as PVA) fiber (trade name: Vinylon; manufactured by Kuraray) having m ² , single fiber elastic modulus of 5000 kg / mm ² , and single fiber breaking elongation of 4.9% ) To prepare a weft knitted fabric having a basis weight of 200 g / m ² . The flat knitted fabric is placed on a concave and convex formwork having a hemispherical curved surface with a radius of 13 cm.
After laminating the layers and arranging them together, an unsaturated polyester resin is poured into the layers and impregnated with the layers, and the temperature is 50 kg / mm for 2 hours at room temperature.
The composition was cured at a press pressure of ² and then heat-cured at 80 ° C. for 1 hour to form an FRP. This FRP was subjected to a three-point bending test and a penetration resistance test. The results are shown in Table 1.

Example 2: Single fiber strength is 330 kg / m
Filament (1500 denier / 3) of polyarylate fiber (trade name: Vectran fiber; manufactured by Kuraray) having m ² , single fiber elastic modulus of 7600 kg / mm ² and single fiber breaking elongation of 4.0%
00 filament) to produce a weft knitted fabric having a basis weight of 220 g / m ² . After 16 layers of the flat knitted product are laminated and arranged on a concave-convex mold having a hemispherical curved surface with a radius of 13 cm, an unsaturated polyester resin is poured and impregnated therein, and a pressing pressure of 50 kg / mm ² is applied at room temperature for 2 hours. And then heat-cured at 80 ° C for 1 hour for FRP
Was molded. A three-point bending test and a penetration resistance test were performed using this FRP. The results are shown in Table 1.

Comparative Example 1: Single fiber strength was 80 kg / mm ² ,
Single fiber elastic modulus is 1270 kg / mm ² , single fiber breaking elongation is 1
A weft knitted fabric having a basis weight of 200 g / m ² was produced using filaments (1000 denier / 192 filaments) of 5.0% polyester fiber (trade name: Kraftel; manufactured by Kuraray). After 14 layers of this weft knitted product are laminated and arranged on a concave and convex mold having a hemispherical curved surface with a radius of 13 cm as in the example, an unsaturated polyester resin is poured and impregnated therewith, and the resultant is kneaded at 50 kg / mm for 2 hours at room temperature. ^{And then} heat-hardened at 80 ° C for 1 hour to obtain FRP
Was molded. This FRP was subjected to a three-point bending test and a penetration resistance test. The results are shown in Table 1.

Comparative Example 2: Filament of the same fiber as the PVA fiber used in Example 1 (1800 denier / 100
0 filament) to make a plain weave. The number of punches of this plain fabric is 11 / inch, and the basis weight is 2
00 g / m ² . This plain woven fabric is cut into a concave and convex formwork having a hemispherical curved surface with a radius of 13 cm, and 13 layers are laminated and arranged on the formwork. An unsaturated polyester resin is poured into the plain fabric and impregnated therein. 2 hours, 50kg
The composition was cured at a press pressure of / mm ² , and further heat-cured at 80 ° C. for 1 hour to form an FRP. This FRP was subjected to a three-point bending test and a penetration resistance test. The results are shown in Table 1.

Comparative Example 3 A plain weave was made using filaments of the same fibers as the polyarylate fibers used in Example 2 (1500 denier / 300 filaments). The number of punches of this plain fabric was 15 / inch, and the basis weight was 220 g / m ² . This plain woven fabric is cut into a concave and convex formwork having a hemispherical curved surface with a radius of 13 cm, and 13 layers are laminated and arranged on the formwork. An unsaturated polyester resin is poured into the plain fabric and impregnated therein. Cured for 2 hours with a pressing pressure of 50 kg / mm ² ,
For 1 hour to form an FRP. This FR
P was subjected to a three-point bending test and a penetration resistance test. The results are shown in Table 1.

COMPARATIVE EXAMPLE 4 The same plain woven fabric as the PVA fiber used in Comparative Example 2 was used.
The 13 layers are stacked and arranged on a concave / convex mold having a hemispherical curved surface of m so as to fit the mold as much as possible without cutting, and an unsaturated polyester resin is poured and impregnated into the mold, and 50 kg for 2 hours at room temperature. The composition was cured at a press pressure of / mm ² , and further heat-cured at 80 ° C. for 1 hour to form an FRP. However, in the obtained FRP, the woven fabric overlaps at the end portion and the resin is not impregnated, and such a resin-impregnated or insufficiently impregnated portion accounts for about 30% of the whole, and the product is clearly a product. It became a worthless molded product. That is, from this example, it was reproduced that it was difficult to obtain a good FRP having hemispherical irregularities using a plain woven fabric using high-strength fibers without cutting.

[0016]

[Table 1]

Example 1 and Comparative Example 2 are examples in which the same PVA fiber was used as the reinforcing fiber material, but the latter performed a molding operation by cutting a plain woven fabric along a formwork.
The former uses a knitted material and can be performed without cutting, so not only can the molding work be significantly labor-saving, but also
As shown by the above, it has excellent properties as a deep drawing FRP. On the other hand, in the latter, as a result, the deep drawability is poor, and the characteristics of the FRP are reduced at the cut portion of the woven fabric, so that the characteristics cannot be exhibited as the deep draw molded FRP. Comparative Example 1 is an example in which a conventional general-purpose organic synthetic fiber having low strength characteristics is used, and is used as a knitted fabric. The deep drawability is good, but the bending strength of FRP is low, and the penetration Is also big. Example 2 and Comparative Example 3 are the high-strength PVA used in Example 1 and Comparative Example 2.
This is an example in which a polyarylate fiber having a higher strength and a higher elastic modulus than that of the fiber is used. The bending strength of the FRP is also improved due to its high fiber strength and elastic modulus. Poor, does not improve penetration. On the other hand, in the case of Example 2, the deep drawing property is good, and the excellent deep drawing strength with good fiber strength and low penetration is utilized.
RP is obtained.

[0018]

According to the present invention, the single fiber tensile strength is 100
The FRP obtained by deep drawing using a knitted fabric made of an organic synthetic fiber having a tensile modulus of elasticity of 4000 kg / mm ² or more and a single fiber tensile modulus of 4000 kg / mm ² or more is compared with the FRP obtained by knitting a polyester of general-purpose organic synthetic fiber. As a result, both the bending strength and the impact resistance are improved, and the performance is greatly improved as well as the workability as compared with the FRP formed by cutting and forming a woven fabric. Therefore, the FRP obtained by the present invention can be used not only as an outer plate of automobiles, vehicles, ships, bathtubs and the like, but also as a helmet material, as a reinforcing material for toes or heels of safety shoes, and in bags, cases, and outboards. It can be applied to a wide range of uses, such as as a machine cover.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-69605 (JP, A) JP-A-63-135232 (JP, A) JP-A-63-135508 (JP, A) 275729 (JP, A) JP-A-63-30209 (JP, A) JP-A-1-259932 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 70/10 B29B 11 / 00-15/14

Claims (1)

(57) [Claims] 1. A single fiber tensile strength of 100 kg / mm ² or more,
A fiber-reinforced resin molded product formed by deep drawing using a knitted product made of an organic synthetic fiber having a single fiber tensile modulus of 4000 kg / mm ² or more as a reinforcing material.