JPH08325889A - Semirigid complex sail cloth - Google Patents

Abstract

PURPOSE: To obtain a lightweight semirigid sail cloth, excellent in impact resistance and shape stability by compounding a base fabric containing high-strength and high-elastic modulus polybenzazole fibers with a resin and/or a film. CONSTITUTION: This semirigid sail cloth is obtained by weaving a plain weave fabric having >=1.00, preferably >=1.50kg/g/m<2> basis weight strength in both the warp and the weft directions from polybenzazole fibers of 250-500 denier having >=150GPa elastic modulus and >=4.0GPa strength as warp yarns and/or weft yarns, then laminating a biaxially oriented film coated with a urethane- based adhesive to the resultant woven fabric or impregnating the woven fabric with a water-dispersible completely reactive urethane coating liquid containing a pigment or a dye and carrying out the drying and curing treatment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-performance sail cloth capable of effectively converting wind power into propulsion. More specifically, the present invention relates to a sail cloth based on a cloth containing high-strength and high-modulus polybenzoxazole fiber.

[0002]

2. Description of the Related Art There is a demand for a high-performance sail cloth that has high strength, is excellent in impact resistance, and can effectively convert wind power into the propulsive force of a ship. For this reason, a composite sail cloth using a woven fabric of super fiber having high strength and high elastic modulus as a reinforcing material is used, but conventional materials cannot be said to be sufficient. That is, the composite sail using the carbon fiber cloth as a reinforcing material is not practical because the carbon fiber is weak in bending, and the composite sail using the para-aramid cloth cannot be said to have sufficient breaking strength and impact strength per weight. In the case of ultra-high-strength polyethylene (trade name: Dyneema, etc.) fabric, the breaking strength and impact strength are within the practical range, but due to insufficient adhesion, the composite sail does not have sufficient bending strength and There is a defect that so-called fluttering easily occurs due to the flow, and the ability to cut up windward cannot be sufficiently obtained.

[0003]

DISCLOSURE OF THE INVENTION The present invention is to provide a composite sail which has hitherto been unattainable, is extremely lightweight, has excellent impact resistance, and has good morphological stability due to bending resistance.

[0004]

The present invention uses a polybenzazole fiber having a high strength and a high elastic modulus exceeding carbon fiber as a reinforcing material to obtain a composite sail having properties that have hitherto been unattainable. succeeded in. The present invention is directed to the construction of a composite sail that is particularly suitable for small sailing ships.

The present invention will be described in detail below. The polybenzazole fiber in the present invention means a fiber made of polybenzazole polymer, and polybenzazole (PBZ)
The term "polybenzoxazole (PBO) homopolymer, polybenzothiazole (PBT) homopolymer and random, sequential or block copolymers of PBO and PBT". Here, polybenzoxazole, polybenzothiazole and their random, sequential or block copolymers are, for example, described in "Liquid Crystalline Polymer C" by Wolfe et al.
ompositions, Process and Products "US Patent No. 47
03103 (October 27, 1987), "Liquid C
rystall-inePolymer Compositions, Process and Prod
ucts "US Pat. No. 4,533,692 (August 6, 1985)
Sun), "Liquid Crystalline Poly (2,6-Benzothiazole)
Composition, Process and Products "US Patent No. 45
No. 33724 (August 6, 1985), "Liquid Cryst
alline Polymer Compositions, Process and Products
US Pat. No. 4,533,693 (August 6, 1985)
Sun), Evers' Thermooxidative-ly Stable Articula
ted p-Benzobisoxazole and p-Benzobisthiazole Polym
res "U.S. Pat. No. 4,539,567 (November 16, 1982), Tasi et al.," Method for making Heterocyclic ".
Block Copolymer "US Pat. No. 4,578,432 (19
March 25, 1986), etc. The structural unit contained in the PBZ polymer is preferably selected from lyotropic liquid crystal polymers. The monomer unit consists of the monomer units described in structural formulas (a) to (h), and more preferably, essentially, structural formulas (a) to (h).
It consists of monomer units selected from (c).

[0006]

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[0007]

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Suitable solvents for forming the dope of PBZ polymer include cresol and non-oxidizing acids capable of dissolving the polymer. Examples of suitable acid solvents include polyphosphoric acid, methanesulfonic acid and concentrated sulfuric acid or mixtures thereof. Further suitable solvents are polyphosphoric acid and methanesulfonic acid. The most suitable solvent is polyphosphoric acid.

The polymer concentration in the solvent is preferably at least about 7% by weight, more preferably at least 1%.
It is 0% by weight, most preferably at least 14% by weight. The maximum concentration is limited by practical handling characteristics such as the solubility of the polynose and the viscosity of the dope. Due to these limiting factors, the polymer concentration is usually 20% by weight.
Never exceeds.

Suitable polymers, copolymers or dopes are synthesized by known methods. For example, Wolfe et al., US Pat. No. 4,533,693 (August 6, 1985), Sy.
U.S. Pat. No. 4,772,678 to Bert et al. (September 2, 1988)
Day 0, Harris U.S. Pat. No. 4,847,350 (198).
It is synthesized by the method described in July 11, 1997). PB
Z polymers are described in US Pat. No. 5,089,591 to Gregory et al.
According to the publication (February 18, 1992), it is possible to achieve a high molecular weight at a high reaction rate in a dehydrating acid solvent under relatively high temperature and high shear conditions.

From the dope thus polymerized, polybenzazole fiber having high strength and high elastic modulus is produced by a known means. For example, US Pat. No. 5,294,390 (1
The dry-wet spinning method described in May 15, 994) is suitable.

Next, the gist of the present invention is to form a woven fabric by using polybenzazole fiber having strength and elastic modulus superior to that of carbon fiber alone or by hybridizing with other organic fiber. The hybrid woven fabric may be a mixed woven fabric or a combination of the respective woven fabrics. The woven fabric is generally a biaxial woven fabric, but may be a triaxial woven fabric.

Even with the conventional sail cloth, even if the super fiber is used, the softness of the waist of the sail causes damage, so that an ideal sail shape cannot be obtained. Further, if a film or a resin coat is applied to them to obtain bending hardness, there is a fatal defect that the weight increases and the requirement for a lightweight sail is not met.

Up to now, organic super fibers have been proud of their specific strength and elastic modulus, but in fact, they have been used in sails for yacht races to reduce their weight and improve the lift of the sails.
In this respect, it has shown satisfactory performance as compared with conventional general-purpose organic fibers represented by polyester and nylon.
However, in the case of pursuing the sail's lift to the maximum, in high-performance race boats and energy-saving ships using wind power, the sail cross is treated with resin or film coating to make the sail shape closer to the ideal shape, and the sail weight will be lighter. There was a fatal drawback of being damaged. However, since the polybenzazole fiber has mechanical properties twice or more that of aramid, there is a possibility that the problems of these super fiber composite sails can be solved at once.

In the present invention, as a result of diligent studies in order to make use of the mechanical properties and impact resistance of organic fibers beyond the conventional wisdom in a composite sail, as a result, a woven fabric made of polybenzazole fiber was used as a resin and / or a film. It was found that the intended purpose can be achieved by combining them into a semi-rigid sail structure. That is, as for the breaking strength and impact resistance of such a sail, it is necessary that the composite sail has a vertical and horizontal basis weight (fabric strength / weight) of 1.00 kg / g / m ² or more, and stable from light wind to strong wind. In order to obtain the sail lifting force, the sail base cloth must have morphological stability. For this reason, the bending stiffness must be 40,000 kgf / cm ² or more (preferably 50,000 to 120,000 kgf / cm ² ). I found a thing. Next, a method for producing a composite sail having such characteristics will be described.

The sail woven fabric may be a woven fabric composed of polybenzazole fibers alone or in combination with other fibers, and a combination of a single layer or a plurality of laminated layers with or without a base fabric is preferable, but a woven fabric of both fibers may also be used. Good. If the woven fabric consists of biaxial fabrics,
Offsetting the axes of the alternately laminated fibers by 45 ° helps to make the mechanical properties of the laminated structure isotropic.

The fiber woven fabric is usually a plain weave biaxial woven fabric and the basis weight is preferably 100 g / m ² to 500 g / m ² , but the basis weight is not limited. The woven fabric may be a triaxial or multiaxial woven fabric.

The polybenzazole fiber used is preferably surface-treated by corona treatment or the like in order to improve the adhesiveness with the resin. Measured by ESCA,
It is desirable that the amount of oxygen on the surface is 20% or more with respect to the amount of carbon. In addition, it is more suitable if it is treated with a surface treatment agent containing an epoxy resin or isocyanate.

The elastic modulus of the polybenzazole fiber also has an important effect on the performance of the composite sail. In other words, similar attempts to date using organic fibers have a basis weight as a base fabric.
Even if it is lightweight at 150 g / m ² and sufficient strength (1.0 kg / g / m ² or more in the same direction) is obtained, the coating weight of the resin will soon exceed 200 g / m ² and the meaning of weight reduction will be lost. Becomes Therefore, the polybenzazole fiber used in the present invention needs to have an elastic modulus of 150 GPa or more and a strength of 4.0 GPa or more.

The woven fabric is made of polybenzazole fiber having a denier of 250 to 500 denier and the weft yarn and / or the warp yarn of inch.
The plain weave is used to make 30 to 100 pieces, and a woven cloth with a basis weight of 50 to 500 g / m ² is made. A composite sail is manufactured by laminating a 50 μ biaxially stretched film coated with a urethane adhesive on a woven cloth or by directly coating the urethane adhesive. A film-laminated sail is good for this purpose when it comes to only one layer of sail for high performance racing yachts. In the case of an energy-saving sailing ship, etc., further rigidity is required, so a composite sail in which a woven fabric has multiple layers and is impregnated with a urethane resin is suitable. Of course, the impregnating resin may be a thermosetting resin or a thermoplastic resin, but a resin having a high hardness is not preferable. As the resin, in addition to urethane resin, acrylic resin, melamine resin, polyester resin, nylon resin and the like are preferable.

The addition of a pigment to the impregnated resin is an effective method for improving the weather resistance, enabling the use of expensive materials for a long period of time, and reducing the running cost. The method is also effective for giving a desired coloring to the sail. Biaxially oriented polyethylene terephthalate (P
ET) films are generally used, but films having a high elastic modulus such as PEN biaxially stretched films and aromatic polyamide films are more preferable. In particular, the sail base fabric of the present invention in which PBO fibers are used for the fabric has an extremely high elastic modulus, which allows the use of a high elastic modulus film having a low elongation which could not be used with these conventional base fabrics. It is especially effective for America's Cup and the like, which requires sail morphological stability from light to breeze.

The resin treated and / or film laminated composite fabric is further calendered to provide surface smoothness. <Bending stiffness measurement method> Bending stiffness is measured according to JIS-K-7106. A test piece is cut into a width of 10 ± 0.5 mm and a length of 60 mm along the warp and weft directions, measured, and the bending stiffness E (kgf / cm ² ) is calculated using the following formula. E = (4S × M0 × n) / (b × h ³ × 100 × φ) S: Distance between fulcrums (cm) b: Specimen width (1cm) h: Specimen thickness (cm) M0: Load Pendulum moment at 100% scale (kgfcm) φ: Bending angle (rad) n: Reading of load scale corresponding to bending angle φ (rad) (%)

[0023]

EXAMPLES Examples will be shown below, but the present invention is not limited to these examples. <Example 1> Examples 1, 2, 3, 4 (above examples) and Examples 5, 6,
A plain woven fabric of No. 7,8 (Comparative Example) was prepared, impregnated with a water-dispersion type fully reactive polyurethane coating agent, dried and cured to prepare a composite fabric for sail. The characteristics of the obtained composite fabric are shown in Table 1. It can be easily understood that the composite fabric using the PBO fiber has sufficient bending rigidity, is extremely lightweight, and has high breaking strength.

[0024]

[Table 1]

Example 2 Furthermore, a composite fabric in which a 50 μ biaxially stretched film was laminated with an isocyanate cross-linked polyester adhesive using the base fabric of Example 1 of the present invention and two sheets were laminated to form a water-dispersion system complete reactivity. A polyurethane coating agent was impregnated, dried and cured to prepare a composite fabric for sail. The properties of the obtained composite fabric are shown in Table 2. Since it has sufficient bending rigidity, it can be seen that it has sufficient sail shape stability and sufficient sail strength as a composite sail for energy-saving ships. With conventional technology, these numbers were a dream story.

[0026]

[Table 2]

[0027]

EFFECT OF THE INVENTION A semi-rigid composite sail using a base fabric made of a fabric containing high-strength, high-modulus polybenzazole fiber can easily convert wind power into propulsion power, and can realize an energy-saving or high-performance wind-powered sailing ship.

Claims (5)

[Claims] 1. The bending stiffness in the warp direction and the weft direction is 4
A semi-rigid sailcloth characterized by a weight of 0,000 Kgf / cm ² or more. 2. The elastic modulus of polybenzazole fiber is 150 GPa.
As described above, the strength is 4.0 GPa or more.
The described semi-rigid sailcloth. 3. The basis weight is 1. in both warp direction and weft direction.
The semi-rigid sail cloth according to claim 1, which is made of a fabric having a weight of 00 kg / g / m ² or more. 4. The areal strength is 1. in both the warp direction and the weft direction.
The semi-rigid sailcloth according to claim 1, which is made of a fabric having a weight of 50 kg / g / m ² or more. 5. The semi-rigid sailcloth according to claim 1, wherein a pigment, a dye or the like is blended for the purpose of coloring / shading.