JPH0345334A - Fiber reinforced plastic and reinforcing material therefor - Google Patents

Abstract

PURPOSE:To obtain fiber reinforced plastic, in which ply separation strength, maximum bending strength and impact resistance are favorably balanced one another, by a structure wherein reinforcing material produced by integrally bonding intermediate layer, which is made of polymeric polyethylene fiber yarn having high strength and high elastic modulus in tension, and front surface layer and rear surface layer, both of which are fiber yarn other than the above-mentioned fiber yarn and have favorable adhesion, is empolyed. CONSTITUTION:The reinforcing material for fiber reinforced plastic concerned is fabric, which is produced by mixing weaving at least two kinds of fiber yarns in a plurality of plys or in three plys and more and concretely which consists of intermediate layer mainly made of polymeric polyethylene fiber yarn 1 having the tensile strength of 20g/de or more and the elastic modulus in tension of 500g/de or more and front surface layer and rear surface layer mainly made of other fiber yarns 2 and 3 under the condition that said front surface layer, intermediate layer and rear surface layer are integrally bonded together. Further, in the fiber reinforced plastic concerned, at least one sheet or a plurality of sheets of said reinforcing member for fiber reinforced plastic are used in lamination.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a fiber-reinforced plastic that is lightweight and has good impact absorption properties, and a reinforcing material thereof.

(Prior art) #& fiber-reinforced plastics, which are reinforced with inorganic fibers, have excellent tensile, compressive, and bending properties, and are lightweight, so they are used as structural materials in place of metals in some fields. It became so. In particular, carbon fiber reinforced materials are excellent in lightness in addition to the characteristics listed in -1-, and are used as structural materials for space vehicles such as artificial satellites and rockets, as well as for sports. It has also come to be used in bicycles, wheelchairs, robots, etc.

However, fiber-reinforced plastics using carbon fiber as a reinforcing material are brittle against impact and are prone to crack propagation and complete destruction. The reason for this is that in addition to the extremely low elongation of carbon fiber, epoxy resin, which is commonly used as a 7-trix material for fiber-reinforced plastics for structural materials, has excellent heat resistance and chemical resistance. One example is that it is fragile. In order to remedy these shortcomings, we have developed improved carbon fibers with high strength and high elongation from the perspective of reinforcing fibers, and improved carbon fibers that maintain the physical properties of the epoxy resin body from the perspective of matrix resin. al
Although improved resins have been developed, they have not yet met market requirements.

Recently, in order to compensate for the brittleness of carbon fiber by compositing it with other fibers, we have developed a reinforced resin layer using carbon fiber as a reinforcing material and aramid fiber with excellent impact resistance or aramid fiber with high strength and high modulus. Attempts have been made to laminate reinforced resin layers using high molecular weight polyethylene fibers as reinforcing materials.

(Problems to be Solved by the Invention) Fiber-reinforced plastics consisting of a reinforced resin layer using carbon fibers and a reinforced resin layer using aramid fibers have higher impact resistance than fiber-reinforced plastics using only carbon fibers as a reinforcing material. On the other hand, in order to achieve the toughness required by the market, it is necessary to considerably increase the amount of aramid fiber used, and in this case, the compressive and bending properties of fiber reinforced plastics will deteriorate. In addition, since the water absorption rate of aramid fiber is high at 3.5z in the standard state, its physical properties deteriorate due to water absorption in the sexual state.Furthermore, the specific gravity of aramid fiber is 1.45, the highest among organic fibers. On the other hand, fiber-reinforced plastics consisting of a reinforced resin layer of carbon fiber and a reinforced resin layer of high-molecular-weight polyethylene fiber have the disadvantage that the high-molecular-weight polyethylene fiber is less durable than aramid fiber. It is lightweight, has low water absorption, and has excellent impact resistance.
Since the adhesion with the matrix resin is not good, there is a problem in that the carbon fiber reinforced resin layer and the high molecular weight polyethylene fiber reinforced resin layer tend to peel off at the boundary due to impact.

This invention improves the properties of fiber-reinforced plastics reinforced with carbon fibers, glass fibers, and other inorganic fibers by combining them with high-molecular-weight polyethylene fibers, and also improves fiber-reinforced plastics that do not cause delamination and such fiber-reinforced plastics. This is a reinforcing material suitable for the production of plus decks.

(Means for Solving the Problems) The reinforcing material for fiber-reinforced plastics of the present invention is a fabric in which at least two types of fiber threads are mixed and woven into three or more layers, in which one fiber thread is 20 F threads. /denier or higher and a tensile modulus of 500 g/denier or higher. A 1.6-molecular polyethylene fiber yarn, the fiber yarn mainly comprising 1. It constitutes the middle layer of the writing fabric, other fiber threads mainly constitute the surface layer and the back layer, and these front layer, middle layer and back layer are bound by binding.
・It is characterized by being embodied.

In addition, the fiber-reinforced plastic of the present invention is one in which one sheet of the reinforcing material for fiber-reinforced plastics described in 1- is used as a reinforcing material, and a plurality of sheets of the reinforcing material for delicate reinforced plastics described above are used as a reinforcing material. Product R t-' 7 is also good, and the above-mentioned fiber-reinforced plus J. It may also be laminated in combination with other reinforcing materials.

Among the fibers gtl' yarns used in this invention, the tensile strength is 7.
0F, /anyl or more, preferably 30 g/denier or more, more preferably 40 g/denier or less, and has a tensile modulus of 500 g/denier or more, preferably 800 g
/ tail or more, more preferably 1000 g / denier or more - 42 high strength, high modulus item 7-flat polyethylene l
It is preferable that the high molecular weight polyethylene fiber is a non-fiber yarn and has a viscosity average molecular weight of 500,000 or more, and the fineness of the high molecular weight polyethylene fiber is 0.2. A denier of 5 to 10 is preferred.

Further, among the at least two types of fiber yarns, the yarns other than the high molecular weight polyethylene fiber yarns are fibers used as the reinforcement material 4 of fiber reinforced plastics, such as carbon fibers, glass fibers, aramid fibers, Whole aromatic body J
- A yarn consisting of stellate fibers, etc., especially carbon fibers and lirus fibers (71-ricks tree moon);
Contact with: n ('! (1-Excellent and the fiber is flI desirable.

The reinforced moon of this invention has a fiber thread number of 12 or more on the upper surface,
2, layer 13 and above, layer 15, layer 15, and cross-knit weave. The surface layer and the back layer are each composed of fiber threads other than high molecular weight polyethylene fiber threads so that most of the polyethylene fiber threads are located in the intermediate layer other than the surface layer and the back layer, resulting in a "double surface layer". , the intermediate layer and the surface layer are joined and integrated by the constituent fiber threads of the surface layer, intermediate layer or back layer described in -, or fiber threads other than these.

FIGS. 1 and 2 show a woven fabric with a layered structure suitable as the sleeve reinforcement. Figure 1 shows a warp double woven fabric woven using high molecular weight polyethylene fiber threads for the weft thread 1 and other fiber threads for the front warp threads 2 and back warp threads 3. By making the surface twill and covering the surface with the front warp yarns 2, the surface layer is made up mainly of other fiber yarns, and by making the opposite back structure a weft twill and covering the back side with the back warp yarns 3, the back layer is made mainly of other fibers. Most of the weft yarns 1 are located between the surface layer and the back layer, and the intermediate layer is mainly composed of high molecular weight polyethylene fiber yarns,
A part of the front warp yarn 2 is submerged under the weft yarn 1, and a part of the back warp yarn 3 is floated above the weft yarn l to connect the front and back tissues and integrate the front layer, middle layer, and back layer. .

Figure 2 is an example of warp/weft double fabric, with front weft 4
High molecular weight polyethylene fiber yarns are used for the a and back weft yarns 5a, and other fiber yarns are used for the front warp yarns 4b and the back warp yarns 5b, respectively, and the front fabric 4 is made into a warp twill.
In addition, the back fabric 5 is woven in a weft twill, so that many of the front warp yarns 4b are exposed on the surface, and the surface layer is composed of other fiber threads, and the back surface layer is made up of other fiber threads by making many of the back warp yarns 5b appear on the front surface. While it is composed of fiber yarns, many front weft yarns 4a and back weft yarns 5a are located in the part where the front fabric 4 and the mm object 5 are in contact, and these high molecular weight polyethylene fiber yarns constitute an intermediate layer, and the front fabric 4 And the scented fabric 5 is connected with the front warp yarns 4b and the back warp yarns 5b to integrate the front layer, the middle layer and the back layer.

In this way, the surface layer and the back layer are mainly composed of other fiber threads, and the middle layer is mainly composed of high molecular weight polyethylene fiber threads, but the area of the other fiber threads that occupies the surface layer and the back layer is is preferably 60% to 90% of the total area, and the above area is 60%
If it is less than 90%, no effect of improving adhesion is observed and shear peeling tends to occur, and if it exceeds 90%, the number of bonding points decreases and shear peeling tends to occur between the surface layer or back layer and the intermediate layer.

As the 71-lithox resin used in the fiber-reinforced plastic of the present invention, any resin can be used as long as it is finally cured at 145° C. or lower or by removing the solvent. Examples include polyester urethane, aliphatic hydrocarbon polymer, aliphatic hydrocarbon copolymer, or unsaturated polyester resin, vinyl ester resin, epoxy resin, phenolic resin 51 ruthane acrylate 1, and the like. , [1] To obtain a fiber-reinforced plastic with load impact resistance, a thermosetting phase sequence with improved toughness;
Epoxy resins are particularly preferred.

These 71 to Rix resins are impregnated into the above-mentioned sleeve reinforcing material made of a cross-knitted fabric containing 1'h molecular weight polyethylene 1-non fiber yarn L7. A first prepreg sheet i- is formed. Further, a second bripreg sheet is formed by impregnating a sheet 1-shaped reinforcing material such as a nonwoven fabric or a knitted fabric made of fibers other than high molecular weight polyethylene fibers, such as glass fiber or carbon fiber. Then, ``by laminating the double first prepreg sheets 1~ alone or by laminating a combination of the first prepreg sheet and the second prepreg sheet, and then thermoforming'' the double prepreg sheet 1 The fiber-reinforced plastic of the present invention is obtained by curing the laminate and adhering at the same time. FIG. 3 shows a case in which only double first prepreg sheets are laminated and cured, and 6 is a first prepreg sheet consisting of the first prepreg sheets 1 to 1.
6a is the front surface m, 61) is the middle layer, and 6c is the back layer. In addition, FIG. 4 shows the first prepreg sheet 1-
and the second prepregsy 1- are alternately stacked and cured, and 6 is the double fourth reinforcing resin layer, and 7 is the second reinforcing phase-sequential layer consisting of the second prepregsy 1-.

(Function) The 041 reinforced plastic ivy of this invention is intermediate J? 71
Mainly polymer paper polyethylene ξ1! A reinforcing material is used in which the surface layer and the back layer are mainly composed of other fiber threads, and the other fiber threads have excellent adhesive properties. Both when used alone and in combination with reinforcing materials made of other fibers, fibers with good adhesiveness come into contact with each other in adjacent areas of the reinforcing material, resulting in good adhesion and no peeling. Does not occur.

In addition, the intermediate layer of the double-sleeve reinforcement is composed of high-molecular-weight polyethylene fiber threads that have poor adhesion but excellent impact resistance, so the impact resistance of fiber-reinforced plastics is improved by -1. .

(Example) Tensile strength 32g/denier, tensile strength 15111 skewer 135
0/denier, viscosity average molecular weight 1 million, thickness 1200
Denyl high molecular weight polyethylene fiber yarn (manufactured by Dyneema Co., Ltd., Dyneema 5K-60) was used as the warp yarn, and glass fiber yarn (manufactured by Tobo Co., Ltd., ECG 3) was used as the warp yarn.
7 l10) was used for the front weft and back weft, respectively, the warp yarn density was 5.9 threads/■ (155 wood/inch), the weft thread density was 11.8 threads/an (300 wood/inch), the front weft was weft twill, and the back weft was A warp-twill and horizontal double-layered fabric was woven, and the front and back layers were each mainly composed of glass fiber yarns, and the middle layer was composed of high molecular weight polyethylene fiber yarns. In this case, the area occupied by the glass fiber threads in the front and back layers was 75% of the total area.

A reinforcing material made of double-width double-woven fabric is impregnated with vinyl ester resin and dried at 90°C for 10 minutes to obtain prepreg sheets 1 to 3.
(see figure), this laminate was placed in a heat press machine and heated to 120°C.
Press molding was performed for 15 minutes to obtain a flat fiber-reinforced plastic of Example 1.

Its thickness is 2.5nwn, fiber content (Vf) is 60%
Met.

A prepreg sheet 1- was obtained in the same manner as in Example 1, except that carbon fiber yarn (manufactured by Toho Rayon Co., Ltd., 3K) was used in place of the glass fiber yarn in Example 1, and this prepreg sheet 1 was Laminate 6 sheets, set in a heat press machine, 12
Press molding was carried out at 0°C for 15 minutes, and the flat fiber-reinforced plastic of Example 2 (/[X diameter 2.5nwn, 1M
Fiber content (Vf) 6 (1%) obtained.

The high molecular weight polyethylene fiber yarns in the examples were used for both the warp and the weft, and a plain woven fabric with a warp density and a weft density of 5.9 threads/an (155 threads/inch) was woven. On the other hand, glass fiber yarn (manufactured by Nittobo Co., Ltd., E
CG31110) is used for both the warp and weft, and the warp and weft density are 5.9 threads/a respectively.
A plain woven fabric of 155 mm (155 mm/inch) was woven. ”-Note 2 Each of the plain woven fabrics was made into prepreg in the same manner as in Example 1,
As shown in FIG. 5, four sheets of prepreg 8 made of high molecular weight polyethylene fiber and six sheets of prepreg 9 made of glass fiber are alternately laminated at a ratio of 72 sheets each, resulting in a laminate consisting of a total of 10 sheets of prepreg. Place it in a heat press machine and heat it to 120℃×
Press molding was performed for 15 minutes to obtain a fiber-reinforced plastic as a comparative example. The fiber content (Vf) was 2.5 nwn, and the fiber content (Vf) was 60%.

A prepreg was manufactured in the same manner as in Comparative Example 1, except that carbon fiber yarn (manufactured by Toho Rayon Co., Ltd., 3K) was used instead of the glass fiber yarn in Comparative Example 1, and the high molecular weight polyethylene fiber of Comparative Example 1 was used. Three sheets of prepreg and four sheets of the above carbon fiber prepreg were alternately laminated at a ratio of 15 sheets/2 sheets, and the laminate consisting of a total of 6 sheets of prepreg was placed in a heat press machine and pressed at 120°C for 15 minutes. Molding was performed to obtain a flat fiber-reinforced plastic of Comparative Example 2. Its thickness is 2.5+nm, 11! Fiber content (Vf) is 60
%Met.

In addition, commercially available carbon fiber yarn (manufactured by Toho Rayon Co., Ltd., 1
K) was used for both the warp and weft, and a plain fabric with a warp density and a weft density of 7.1 wood/(1) (188 wood/inch) was woven, and this was made into prepreg in the same manner as in the example above. As shown in FIG. 6, 28 sheets of this prepreg sheet)-10 were laminated and molded using a hot press machine to obtain a flat fiber reinforced plastic of Comparative Example 3. Its thickness was 2.5 mm, and its 11 fiber content was 60%.

” The glabella shear strength (kg/n
wn2), maximum bending strength (pupil/m2) and falling weight impact energy (J), the results shown in the table below were obtained.

As is clear from the table above, the fiber-reinforced plastic of Comparative Example 3, which uses a fabric made only of carbon fiber threads as a reinforcing material, has significantly higher interlaminar shear strength and maximum bending strength than the others, but has low impact resistance. The value is extremely low. In order to improve the WiF impact resistance of Comparative Example 3, the fiber-reinforced plastic of Comparative Example 2 was laminated with a fabric made of 7-ffi polyethylene fiber yarn having high strength and high elastic modulus.
While impact resistance is improved, both interlaminar shear strength and maximum bending strength are significantly reduced. Also, ``Comparative Example Using Glass Fiber Instead of Carbon Fiber in Comparative Example 2 in Section 8'' is? f[While the resistance further increases, the single-layer shear strength and maximum bending strength further decrease. On the other hand, Example 1.2 of the present invention uses a mixed woven fabric in which the high molecular weight polyethylene fiber yarn of the intermediate layer and the carbon fiber yarn or glass fiber yarn of the surface layer and back layer are integrated by binding. Since it is a reinforcing material, the impact resistance is significantly improved compared to Comparative Example 3, and both the delamination strength and maximum bending strength are significantly improved compared to Comparative Example 1.2.

(Effects of the Invention) The invention according to claim 1 is characterized in that the intermediate layer is mainly composed of high-strength, high-tensile-modulus high-molecular-weight polyethylene fiber yarn,
This reinforcing material for fiber-reinforced plastics consists of the front layer and the back layer mainly composed of other fiber threads with good adhesive properties, and is made of interlaced woven fabric that is integrated by binding. When the fiber-reinforced plastic according to claim 2 is produced by laminating alone or in combination with other fiber reinforcing materials, the impact resistance properties are improved compared to fiber-reinforced plastics reinforced with conventional inorganic fiber threads. In addition, the delamination strength is better than that of fiber-reinforced plastics reinforced with a mixed laminate of conventional inorganic fiber reinforcement and high molecular weight polyethylene fiber reinforcement, and the delamination strength and maximum A fiber-reinforced plastic with a good balance of bending strength and impact resistance can be obtained.

[Brief explanation of drawings]

Figure 1 is a sectional view showing an example of the reinforcing material, Figure 2 is a sectional view of another example of the reinforcing material, Figure 3 is a sectional view of an example of delicate reinforced plastic, and Figure 4 is a fiber reinforced 5 and 6 are cross-sectional views of other examples of plastics, respectively, of fiber-reinforced plastics of comparative examples. 4a, 5a: High molecular weight polyethylene fiber yarn, 2.
3, 4b, 5b = other fiber threads, 6a: surface layer, 6b:
Intermediate layer, 6c: IA surface layer.

Claims (1)

[Scope of Claims] [1] A fabric in which at least two types of fiber threads are mixed and woven in multiple layers, in which one fiber thread has a tensile strength of 20 g/denier or more and a tensile modulus of 500 g/denier or more. A high molecular weight polyethylene fiber yarn, which mainly constitutes the intermediate layer of the fabric, and other fiber yarns mainly constitute the surface layer and the back layer, and the surface layer, the intermediate layer, and the back layer. A reinforcing material for fiber-reinforced plastics, characterized in that these are integrated by bonding. [2] A fiber-reinforced plastic using at least one reinforcing material for fiber-reinforced plastic according to claim 1 as a reinforcing material.