JPH047166Y2 - - Google Patents

Description

[Detailed explanation of the idea]

<Technical Field of the Invention> The present invention relates to fiber-reinforced plastics using high-strength, high-modulus polyvinyl alcohol fibers as a reinforcing material. <Prior art> As a reinforcing material for fiber-reinforced plastics (hereinafter abbreviated as FRP), glass fiber, which has a large reinforcing effect, is the mainstream, and in recent years, carbon fiber has been used as a heat-resistant, high-modulus, or high-strength fiber. and aromatic polyamides are being used. In addition, synthetic fibers are used as reinforcing materials in FRP, which requires impact resistance, and nylon, polyester, vinylon, polypropylene, etc. are used alone or in combination with glass fiber. However, vinylon fiber as a reinforcing material
Yarns with high strength and high elastic modulus have not been obtained industrially, and although yarns produced by conventional wet spinning have good weather resistance, they have low strength and low elastic modulus.
It was not sufficient as a reinforcing material for FRP. <Problems to be solved by the invention> The purpose of the invention is to provide an FRP with high strength, high modulus of elasticity, and excellent impact resistance, water resistance, etc. <Means for solving the problems> The FRP according to the present invention is made of polyvinyl alcohol-based polymer with a degree of polymerization of 1500 or more, has a tensile strength of 15 g/d or more, an initial elastic modulus of 250 g/d or more, and has a multi-functionality. Filament composition: Single filament fineness is 5d or less, long-period images are not observed in small-angle X-ray scattering measurements, and there is virtually no agglutination between single filaments Polyvinyl alcohol fiber is used as a reinforcing material, and synthetic resin is used as a matrix. It is something. The FRP according to the present invention is characterized by the use of high-strength, high-elasticity polyvinyl alcohol (hereinafter abbreviated as PVA) fiber, which has not been previously known, as a reinforcing material. The PVA fiber used in this invention has a tensile strength of 15
g/d or more, preferably 17.5 g/d or more, and an initial elastic modulus of 250 g/d or more, preferably 300 g/d or more, more preferably 350 g/d or more,
The PVA polymer constituting this is not particularly limited as long as its degree of polymerization is 1500 or more, preferably 2500 or more and has fiber-forming properties, such as partially saponified PVA, completely saponified PVA, and Examples include PVA copolymers in which a small amount of vinyl monomers copolymerizable with vinyl alcohol are polymerized. The method for turning such PVA polymer into threads is as follows:
There is a method in which a solution of the polymer is spun from a nozzle using a dry-wet spinning method or a gel spinning method, and then solidified or solidified by cooling. The dry-wet spinning method is a spinning method in which a solution containing the polymer is once discharged into an inert atmosphere such as air, and then the discharged thread is formed into a thread in a coagulation bath or a cooling liquid. Here, the distance that the discharged yarn travels in the inert atmosphere (distance from the mouth surface to the coagulation bath surface) is not particularly limited, but is suitably 3 mm to 50 mm. As solvents for PVA-based polymers in the dry-wet spinning method, organic solvents such as dimethyl sulfoxide (DMSO), glycerin, ethylene glycol, diethylene triamine, ethylene diamine, and phenol, and inorganic solvents such as water, zinc chloride, rhodan soda, calcium chloride, and aluminum chloride are used. Examples include aqueous salt solutions and mixed solvents thereof, but DMSO, diethylenetriamine, and ethylenediamine are particularly preferred, and DMSO is more preferred. From the viewpoint of spinnability, the viscosity of the spinning dope is 200~
5000 poise is selected, preferably 500-2000 poise. Such a spinning dope is discharged through a spinneret placed on the surface of the coagulation bath, and the discharged yarn is guided into the coagulation bath after traveling in air or an inert atmosphere. The coagulation bath may have a common bath composition, but methanol, ethanol, and acetone are particularly preferred. The coagulated yarn undergoes solvent removal, drying, and stretching processes to become a yarn with high strength and high initial elastic modulus. conduct. The final stretching is preferably dry heat stretching, and the stretching temperature is
200-250℃ is good. In particular, polymerization degree of 3100 or more
When using PVA polymer, the total stretching ratio is 30
It is possible to double or more, and in some cases, a strength of 18 g/d and an initial elastic modulus of 400 g/d, which is close to that of aramid fibers, can be obtained. The above-mentioned PVA fiber used in the present invention also has superior light resistance and low cost compared to aramid fibers, and also has excellent abrasion resistance and fatigue resistance. Good surface smoothness. In the present invention, such high-strength PVA fiber woven fabrics, roving cloths, short fiber nonwoven fabrics, rovings, chop strands, etc. are used as reinforcing materials for FRP. Figure 1 shows the high strength and high elasticity PVA used in this invention.
Chopped strands of fibers 1 and glass fibers 2
A bulk molding compound molded plate 4 made of a thermosetting resin 3 and a thermosetting resin 3 is shown. Figure 2 shows the high strength and high elasticity PVA used in this invention.
A laminate 6 made of a roping cloth made of fibers and a thermosetting resin 3 is shown. The matrix resin used in the present invention is not particularly limited, and as in normal FRP production, synthetic resins such as thermoplastic resins such as polyester, polyamide, polyolefin, etc., and thermosetting resins such as unsaturated resins can be used. Polyester resin, epoxy resin, phenol resin, etc. are used. <Effects of the invention> The FRP of the invention maintains high strength and high elastic modulus that cannot be achieved with conventional PVA-based fiber reinforcement materials. Furthermore, since the reinforcing material is dry-wet-spun and has excellent surface smoothness, FRP using this material has excellent impact resistance. The FRP of the present invention, which has such characteristics, can be widely used as bulk molding compound molded products for housing-related parts, protective equipment, and mechanical parts, as well as laminates for helmets, protective equipment, cushioning materials, and automobile parts. . <Example> Tensile strength, initial elastic modulus, small-angle X-ray scattering, and degree of opening were measured according to the following measurement methods. a Tensile strength, initial elastic modulus Using multifilament yarn as a sample, JIS
-Measured according to the test method specified in L-1017. That is, after winding the multifilament yarn into a skein and leaving it in an atmosphere adjusted to 20℃ and 65% RH for 24 hours, a sample was taken from the skein, and a "Tensilon" UTM-4L type tensile tester (Toyo (manufactured by Baldwin), sample length 25
cm, and the tensile speed was 30 cm/min. The initial elastic modulus was measured from the load-elongation curve obtained here according to the definition of JIS-L-1017. b Small-angle X-ray scattering Measured according to a known method using a Kiessig Camera. The following conditions were set as measurement conditions. Uses RU-200 type X-ray generator manufactured by Rigaku Denki Co., Ltd. CuKα radiation (using Ni filter), output: 50Kv−
150mA, using a 0.3mmφ collimator, transmission method, camera radius: 400mm, exposure time: 90 minutes, film: Kodatsu no screen type. c Opening degree Cut the multifilament yarn to 50mm,
When splitting the filament, the ratio of single fibers that can be split without damage such as cutting or fibril cracking was determined according to the following criteria. A multifilament yarn with substantially no interfilament agglutination is defined as having 90% or more of the following criteria: ○: 90% or more △: 70-89% ×: less than 70% Example 1, Comparative Example 1 Completely saponified PVA with a degree of polymerization of 2100 was heated and dissolved in glycerin as a solvent, and the PVA concentration was 18% by weight.
A spinning stock solution was prepared. The spinning dope was made into a pore size of 0.08.
The spinneret was extruded into air through a spinneret with 50 holes and passed through a liquid bath of decalin at 10° C. 10 mm below the spinneret surface for cooling. The gelled yarn obtained by cooling is passed through a dry heat tube at 120°C and once stretched 4 times, the solvent is extracted with water, and the yarn is then transferred to a drying roll while vibrating with turbulent air. fed and dried. The obtained dry yarn was then hot-stretched 4.8 times in a dry heat tube set at 235°C, resulting in high strength and high elastic modulus with a single yarn fineness of 2.15 d, strength of 18.2 g/d, and elastic modulus of 402 g/d. and has no agglutination between single threads,
A PVA multifilament yarn was obtained. Next, the fibers were cut into fiber lengths of 6 mm to obtain reinforcing fibers. Meanwhile, 30 parts of unsaturated polyester resin, CaCO ₃
57 parts, benzoyl peroxide 0.3 parts, MgO 0.3
1 part of zinc stearate was placed in a kneader, and then 1 part of reinforcing fiber was added.
Kneaded for 15 minutes. Next, glass fiber with a fiber length of 6 mm (Nitto Boseki,
CB6E) was added and kneaded for an additional 5 minutes to produce Primics. This Primics was compression molded at 120° C., 100 kg/cm ² for 3 minutes to obtain a molded plate with a thickness of about 3 mm. For comparison, completely saponified PVA with a polymerization degree of 1800 was used instead of the fully saponified PVA with a polymerization degree of 2100 in the above example, and the total stretching ratio was 10 times (pre-stretching = 4 times, post-stretching = 2.5 times). ), but the experiment was conducted under the same conditions. The physical properties of PVA fiber A are as follows. Single yarn fineness: 2.15d Fineness: 1118D Strength: 0.5g/d Elastic modulus: 172g/d The bending strength and impact strength of the obtained molded plate were measured according to JIS-K-6911. The measurement results are shown in Table 1 below. From the table, it is clear that the molded plate using the PVA fiber of the present invention as a reinforcing material has high bending strength and excellent impact resistance.

[Table] Example 2, Comparative Example 2 Single yarn fineness 2.15d, strength 18.2g/d, elastic modulus 402
Fineness 1118 denier D made of g/d PVA fiber
Five filaments are combined to make roving,
Next, the weave density is 36 pieces/inch vertically, 36 pieces/inch horizontally,
A reinforcing roving cloth with a weight of 510 g/m ² was produced by plain weaving. Next, a reinforcing roving cloth was impregnated with a resin containing 100 parts of unsaturated polyester resin and 1 part of Perbutyl Z (hardening agent manufactured by NOF Corporation), and aged at room temperature for 24 hours. The roving cloth impregnated with this resin is used as a mold.
After laminating 10 sheets, they were heated and pressed at 145° C. for 5 minutes to obtain a laminate with a thickness of about 5 mm and a fiber content of 75% by weight. The bending strength of the obtained laminate was measured according to JIS-K-6911, and the impact strength was measured according to ASTM-D-256. Table 2 shows the measurement results. As is clear from Table 2, the laminate using the high-strength, high-modulus PVA fiber of the present invention as a reinforcing material is
High bending strength and excellent impact resistance. Comparative Example 2 was an experiment conducted under the same conditions as Example 2, except that the PVA multifilament obtained in Comparative Example 1 was used as it was (without being cut into staples).

【table】 [Brief explanation of drawings]

FIG. 1 is a perspective view of a bulk molding plate according to the present invention, and FIG. 2 is a perspective view of a laminate. 1... Chopped strand of high strength polyvinyl alcohol fiber, 2... Glass fiber, 3...
Thermosetting resin, 4... Bulk molding compound, 5... Roving cloth of high strength polyvinyl alcohol fiber, 6... Laminated board.

Claims (1)

[Scope of utility model registration request] It is made of a polyvinyl alcohol polymer with a degree of polymerization of 1500 or more, a tensile strength of 15 g/d or more, and an initial elastic modulus of 250 g/d or more, and no long-period image is observed in small-angle X-ray scattering measurements, making it virtually simple. A fiber-reinforced plastic that does not cause stickiness between yarns, uses fibers whose constituent single yarns have a fineness of 5d or less as a reinforcing material, and uses a synthetic resin as a matrix.