JPH032227A - Hybrid prepreg - Google Patents

Abstract

PURPOSE:To obtain hybrid prepreg having increased compression strength by forming two mixed fiber zones having specific two kinds of fiber divisions in a lamellar state in one layer in such a way that mutually different fibers divisions are bonded. CONSTITUTION:Two mixed fiber zones 6 and 7 prepared by arranging a carbon fiber division 3 containing carbon fiber yarn 2 and a different fiber division 5 containing one or more different fiber yarn 4 alternately in parallel are formed in a lamellar state in one layer in such a way that the mutually different fiber divisions are bonded to give the aimed prepreg. A matrix resin 8 is impregnated into between the yarns.

Description

[Detailed description of the invention]

The present invention relates to a hybrid type composite material, and in particular to a hybrid type carbon fiber prepreg (herein simply referred to as "hybrid prepreg") formed of carbon fiber threads and different types of fiber threads. ).

In recent years, prepregs made of carbon fiber reinforced fibers have attracted attention because they are lightweight, have excellent environmental resistance such as heat resistance and water resistance, and have good mechanical properties. Bathing. However, high-modulus carbon fibers, particularly pitch-based high-modulus carbon fibers, have high tensile strength and high tensile modulus, such as a tensile strength of 3.0 GPa or more and a tensile modulus of 450 GPa or more. The strength is low, at best 1.
There is a problem that the pressure is about 0 GPa. Therefore, a carbon fiber prepreg produced using 1 m of high-modulus carbon as a reinforcing fiber has a low compressive strength in comparison with its tensile strength and tensile modulus, and an increase in the compressive strength is desired. Conventionally, hybrid prepregs containing carbon fibers and different types of fibers have been proposed to increase compressive strength.
Currently, hybrid prepregs include living room hybrids formed by laminating carbon fiber prepregs and prepregs of different types of fibers, and hybrid prepregs formed by laminating carbon fiber prepregs and prepregs of different types of fibers, and hybrid prepregs in which carbon #a miscellaneous areas and areas of different types of fibers are placed adjacent to each other in one layer. It is thought that an intralayer hybrid is formed. The former interlayer hybrid is easy to manufacture, but the increase in compressive strength is still not sufficient. In addition, although the latter intralayer hybrid has considerably increased compressive strength compared to the interlayer hybrid and ordinary carbon fiber prepreg, the actual strength of the fibers varies, and weak fibers The degree of increase follows the hybrid compound side and does not exceed the hybrid rule, so it cannot be said that it is still sufficient. As a result of many studies and experiments regarding conventional hybrid prepregs, especially intralayer hybrid prepregs, the present inventors have found that by increasing the contact area between the carbon fiber region and the heterogeneous M11 miscellaneous region as much as possible, In other words, in one layer, there are 281 regions in which carbon fibers and different types of fibers are alternately arranged, and a second region of mixed fibers in which carbon fibers and '74 type fibers are alternately arranged. By forming layers of carbon fibers and increasing the closely bonded area between different types of fibers and carbon fibers, the compressive strength increases dramatically, and the compressive strength exceeds the hybrid 7 compound rule and the hybrid 2 compound rule. We have found that it is possible to increase the The reason why such a phenomenon occurs is not clear, but it is different from the carbon fiber region J+! It seems that the hybrid effect was improved more than expected by increasing the contact area with the fiber region. The present invention has been made based on this new knowledge. It is therefore an object of the present invention to provide a hybrid 2-dobry preg with increased compressive strength. The above-mentioned object of the present invention is achieved by the hybrid prepreg according to the present invention.
As illustrated in the figure, carbon fiber sections 3 containing carbon fiber threads 2 and dissimilar fiber sections 5 containing one or more types of dissimilar fiber threads 4 are arranged in alternating juxtaposition within one layer. The first
A second mixed fiber area 6 in which carbon fiber sections 3 containing carbon fiber threads 2 and dissimilar fiber sections 5 containing one or more types of dissimilar fiber threads 4 are arranged in alternating juxtaposition. Fiber area 7
This is a hybrid prepreg characterized in that these are formed into layers in such a manner that different fiber sections are joined to each other, and a matrix resin 8 is impregnated between the fiber threads. The carbon fiber yarn 2 is pitch-based carbon fiber. PAN-based carbon fiber - Yong-based carbon fiber can be used, but carbon fibers with a high tensile strength and a high tensile modulus, such as a tensile strength of 2-OGPa or more and an elastic modulus of 200 GPa or more, are preferably used. . In addition, the carbon fiber yarn generally has a diameter of 5 to 12, y
A carbon fiber strand (tow) is used, which is formed by gathering and plying 1,000 to 24,000 filaments with a diameter of about m. As the dissimilar fiber yarn 4, any fiber can be used as long as it has a compressive strength greater than that of carbon fiber; for example, silicon carbide fiber! i: alumina MHi; metal fibers such as titanium, steel, stainless steel, beryllium, tungsten, and molybdenum; boron fibers; glass fibers and the like. Preferably, fibers with a compressive strength of 1.5 GPa or more are used, and the fiber threads generally have a filament with a diameter of about 5 to 12 βm [about 1000 to 2400 m].
A strand formed by collecting zero yarns and plying them is used. The matrix resin 8 impregnated into the reinforcing fibers made of the carbon fiber threads and different types of fiber threads includes epoxy resin,
Thermosetting matrix resins such as unsaturated polyester resins, polyurethane resins, diallyl phthalate resins, and phenolic resins can be used, and the curing temperature is 50-15.
A curing agent and other imparting agents 2, such as a flexibility imparting agent, are appropriately added so that the temperature is 0°C. To give a preferred example, epoxy resin is preferred as the matrix resin, and usable epoxy resins include (1) glycidyl ether epoxy resin (
(bisphenol A, F, S-based epoxy resin, novolac-based epoxy resin, brominated bisphenol A-based epoxy resin); (2) cycloaliphatic epoxy resin; (3) glycidyl ester-based epoxy resin: (4) glycidylamine-based epoxy Resin; (5) Heterocyclic epoxy resin: One or more selected from various other epoxy resins are used, and bisphenol A, F, and S glycidylamine-based epoxy resins are particularly preferably used. or,
Diaminodiphenylsulfone (DDS) is used as a curing agent.
), diaminodiphenylmethane (DDM), etc. are preferably used. Manufactured by adjusting the weight of standard matrix resin for reinforcing fibers to 100 to 150 per reinforcing edge m1oo, or by mixing various matrix resins and appropriately blending the 4 parts. . Moreover, such a hybrid prepreg according to the present invention can be suitably manufactured by using drum winding and hot pressing in the same manner as ordinary carbon fiber prepreg, although it is not limited thereto. To briefly explain the manufacturing method, as shown in FIG. 2, first, a thermosetting matrix resin 8 having a viscosity of 100,000 to 5000 poise is coated on a coating paper 8a to a thickness of 0.015 to 0.050 mm. The first resin-coated paper lO coated with the above-mentioned resin is wound and fixed onto the drum D. Next, on the resin-coated paper 10, a plurality of long carbon & a fiber yarns 2 and a plurality of one or more different types of fiber yarns 4 are placed.
are alternately arranged and wound to form the first mixed fiber thread Ff.
j6a and then the first mixture m! l Yarn layer 6
A second mixed fiber yarn layer 7a is formed by winding a plurality of carbon fiber yarns 2 of various lengths and a plurality of one or more different types of fiber yarns 4 in alternating juxtaposition on a. Form. At this time,
The carbon fiber threads 2 of the second mixed fiber thread layer 7a are located on the different types of fiber threads 4 of the first mixed fiber thread layer 6a, and
The different fiber yarn 4 of the second mixed fiber yarn yfI7a is
The mixed fiber yarn layer 6a is positioned above the carbon fiber yarn 2 of the mixed fiber yarn layer 6a. As a result, the first mixed fiber yarn layer 6a and the second mixed fiber yarn layer 7a are layered in parallel on the resin-coated paper 10, and the bonding of both layers 6a and 7a is different from each other. The fiber threads are arranged in such a manner that they face each other. Next, the second resin-coated paper 10 is coated with a viscosity of 100,000 to cover the second mixed fiber yarn layer 7a.
Thermosetting matrix tree J with ~500,000 poise
]'lj8 is coated on paper 8a with a thickness of 0°015 to 0-050
A second resin coated paper 10' coated with 10 mm is wound to form the front prepreg sheet 12. The front prepreg sheet 12 produced in this way is
It is peeled off from drum D and brought to a hot press 20 as shown in FIG. According to this embodiment, the hot press 20 includes a base plate 21 and a press plate 22 that is disposed facing the base plate 21 and is movable up and down. The base plate 21 and press plate 22 are internally equipped with heating means (not shown) such as an electric heater to maintain a desired temperature. The front prepreg sheet 12 is placed on a base plate 21 and pressed by a press plate 22. The pre-prepreg sheet 12 is heated under pressure by the base plate 1-21 and the press plate 22, and the matrix resin 8 is impregnated between the fiber threads 2.4 to form a prepreg. Next, the base plate 21 and the press plate 22 are separated, the prepreg is taken out, and the prepreg is cooled to a predetermined temperature to produce the hybrid prepreg 1 according to the present invention as shown in FIG. 1. Usually, The hybrid prepreg 1 has a thickness t of 0.05 to 0.3 mm, and the thickness of the first mixed M1 miscellaneous region 6 is 1.0 mm. is 0-025
~0°15 mm, thickness t2 of second mixed fiber region 7
is assumed to be 0.025-0.15 mm. In addition, the convergence W1 of the carbon M & miscellaneous section 3 containing the carbon fiber yarn 2 in each mixed fiber region 6.7. Widths W2 and W4 of the dissimilar fiber section 5 containing W3 and one or more dissimilar fiber threads 4 are l −10 m.
It is assumed that m. Radius of fiber compartment Wl, wl, w2, W2
B may be the same, or may be different depending on the case. According to the present invention, various properties can be obtained by changing the physical properties and mixing ratio of the carbon fibers and different types of fibers used, as well as the impregnation ratio with respect to the matrix resin, and by varying the composition ratio of the matrix resin used. A hybrid prepreg is produced that provides compressive strength, tensile strength, tensile modulus, and even toughness of . 4 and 5 are graphs representing hybrid composites of a hybrid prepreg made of carbon fiber/silicon carbide yarn fiber and a hybrid prepreg made of carbon fiber/alumina fiber according to the present invention. See FIG. 4. Then, the strength of the carbon M&fiber is shown by line AB, and the strength of the silicon carbide yarn fiber is shown by line CD. Therefore, a complex or hybrid line is represented by the line AED. It was impossible to achieve the same strength as the hybrid line with conventional carbon fiber/silicon carbide-based hybrid prepregs, but according to the present invention, the compressive strength can be improved by surrounding the line AED. It was possible to increase it until it approached the shaded area. The same was true for the hybrid composite of carbon [1/alumina fiber hybrid prepreg shown in FIG. 5]. As mentioned above, the reason for this is not necessarily clear, but it is thought that the hybrid effect is improved more than expected by increasing the contact area between the carbon fiber and the different type of fiber. Next, the present invention will be described with reference to examples. A hybrid prepreg 1 according to the present invention was manufactured using the drum wine gourd and hot press described in connection with FIGS. 2 and 3 above. As the carbon fiber yarn 2, a strand (tow) made by concatenating 3000 monofilaments with a diameter of 10.4 m was used, and as the different type of fiber yarn 4, silicon carbide yarn fiber (manufactured by Nippon Carbon Co., Ltd., trade name Unikaron, NL201)
It was used. The silicon carbide yarn fiber was a strand (tow) made of 500 monofilaments each having a diameter of 15 μm that were tied together. On the other hand, the resin-coated paper l wrapped around the drum wine goo
The matrix resin 8 on O is Bisphere A-based epoxy resin EP828 (manufactured by Yuka Shell Epoxy Co., Ltd.).
Product name) / EP100I (product name) 50 gr /
50 gr, dicyandiamide 4 as curing agent,
2 gr, DCMU (N-3,4 dichlorophenylene N''-dimethylurea) 4.2 gr. The thickness of the matrix resin layer fixed on the drum wine goo was 0.025 mm. A resin-coated paper 10 is coated with a group of carbon fiber threads in which the carbon fiber threads 2 are made of 3,000 fibers, and silicon carbide threads 4 are made of 500 silicon carbide threads. The carbon #! A carbon m!i yarn group consisting of 3000 pieces of fiber yarn 2 and a silicon carbide fiber yarn group consisting of 500 pieces of silicon carbide fiber yarn 4 are arranged alternately and adjacent to each other. The second mixed fiber yarn layer 7a was arranged and wrapped to form the second mixed fiber yarn layer 7a.Next, an 81-coated paper 10' having the same structure as the resin-coated paper 10 was wrapped around the second mixed fiber yarn layer 7a. The sheet was covered and wrapped to produce a 11-kan prepreg sheet 12 with a thickness of 0.15 mm.Next, the front prepreg sheet 12 was peeled off from the drum wine goo, and was mounted on a hot press and heated under pressure. Pressing force is 20 Kg/c
rrI', temperature was 105°C. The hybrid prepreg l manufactured in this way and having the configuration shown in FIG. 1 has a thickness of 0 to 1 mm.
, the thickness t of the first mixed fiber region 6 and the second mixed fiber region 7
The thickness t2 of both was 0.05 mm. Furthermore, the widths W9 and W3 of the carbon fiber section 3 and the width W2 of the different type of fiber section 5,
W4 is W1 = w3 work 5゜6mm, w2 = w4 = 3
．． It was 8 mm. Further, the amount of reinforcing fiber with respect to the matrix resin, that is, the impregnation rate, was such that the resin/fiber volume ratio was 40,780 in the carbon fiber section 3 and the dissimilar fiber section 5 in the remix m male region 6.7. A test piece T for a bending test having a 20-layer structure and having a size of 12.7 (width) x 9 (thickness) x 140 (length) mm was prepared using 20 of the Hybrid 2 dobbly legs 1. In the test, as shown in FIG. 6, the test piece T is supported at two locations 30 at both ends, and the center f! Load P from 1Zfa place
was applied to bend the test piece T. If an initial break occurs on the tension side of the test piece T, the tensile strength can be estimated, and if an initial break occurs on the compression side, the compressive strength can be estimated. The compressive strength was evaluated by the bending strength at the point where a crack appeared on the compression side of the test piece and the stress decreased. As a result of the test, the initial fracture occurred on the compression side, and the final fracture occurred on the tension side, but it did not break even once. The breaking load on the contact compression side was t±60 kg, the bending strength at this time was 105 kg/mrn', and the strain was 1°44. From FIG. 4, it can be seen that the hybrid prepreg of the present invention has a strength (point X) higher than the hybrid rule (line ED). As illustrated in FIG. Manufactured using goo and hot press. In other words, instead of arranging the carbon fiber yarns 2 and different types of yarns 4 as shown in FIG. The fiber thread groups and silicon carbide fiber thread groups consisting of 500 silicon carbide fiber threads 4 are arranged alternately and adjacent to each other, and these fiber thread groups are coated from both sides with resin-coated paper. A front prepreg sheet was formed by sandwiching the sheets. The pre-prepreg sheet was then peeled off from the drum wine gourd, mounted on a hot press, and heated under pressure. The pressing force of the hot press at this time was 20 kg/cm', and the temperature was 105°C. Hybrid prepreg 40 manufactured in this way
The thickness t is 0.1 mm, and the radius w5 of the carbon fiber section 3 is 2.
．． The width WB of the different fiber section 5 was 1.9 mm. As can be understood from the above structure, the amounts of carbon fiber yarn 2 and silicon carbide fiber yarn 4 used in this comparative example were the same as in Example 1. Further, regarding the amount of reinforcing fibers in the matrix resin, that is, the impregnation rate, the resin/fiber volume ratio was 40/60 in both carbon fiber section 3 and dissimilar fiber section 5. Using 20 sheets of the hybrid prepreg 40, a test piece T for bending test with a 20-layer structure of x2.7 (radius) Xl, 89 (thickness) x 140 (length) mm was prepared, and the test piece T was prepared in the same manner as in Example 1. I did a test. As a result of the test, a crack appeared on the compression side under a load of 40 kg and the product was separated. The bending strength at this time is 70 Kg/
m rn” and the strain was 0.42. From Figure 4, it can be seen that the hybrid prepreg of this comparative example has a strength (point Y) that is less than the hybrid rule (line ED). .L 1" Reinforced monofilament with a diameter of 107 m) 30
A carbon Ia prepreg was produced in the same manner as in Example 1 except that only carbon fiber strands (tow) in which 00 carbon fibers were bundled and spun were used, and tests were conducted in the same manner. As a result of the test, a crack appeared on the compression side with a load of 146 kg, and the product was separated. The bending strength at this time is 74 Kg
/ m rn', and the strain was 0.21. Monofilament 500 with a diameter of 15 μm as reinforcing fiber
A silicon carbide fiber prepreg was prepared in the same manner as in Example 1, except that silicon carbide fiber (manufactured by Nippon Carbon Co., Ltd., product name: Nicalon, NL201) made by binding and splicing books was used, and tested in the same manner. I did it. As a result of the test, cracks occurred on the tensile side under a load of 95 kg, but they did not break. The bending strength at this time is 18
It was 0 Kg/mrn', and the strain was 1.90. 8 layers of the carbon fiber prepreg and silicon carbide fiber prepreg used in Comparative Example 2.3 were used to produce l\Ivery 2 Dobri Preg. Using 10 pieces of the Hybury 7 dobbly preg, it has a 20-layer structure of 12.7 (radius) XL, 89 (thickness) xi40 (&)
A test piece T for bending test of mm was prepared and tested in the same manner as in Example 1. As a result of the test, the crank entered the compression side under a load of 28 kg, causing it to split. The bending strength at this time is 50 Kg/
There was m m'te, and the distortion was 0.26. From Fig. 4, the hybrid prepreg of this comparative example has a strength (point Y') below the hybrid rule (line ED).
It can be seen that it has Example except that an alumina fiber cone (manufactured by Sumitomo Chemical Co., Ltd., trade name = SN-10) in which 1000 monofilaments with a diameter of 15) m were bundled and spliced was used as the fiber yarn 4. Hybrid prepreg I was produced in the same manner as in Example 1 and tested in the same manner. The test results showed that the initial failure occurred on the compression side and the final failure occurred on the tension side, but did not separate. The maximum compression side breaking load was 50 kg, the bending strength at this time was 95 kg/m, and the strain was 1.03. From FIG. 5, it can be seen that the hybrid prepreg of the present invention has a strength (point X) higher than the hybrid rule (line ED). L Comparison 1" A hybrid prepreg 40 was produced in the same manner as in Comparative Example 1, except that the alumina fiber of Example 2 was used as the dissimilar fiber yarn 4, and a test was conducted in the same manner as in Example 1. As a result of the test, a crack appeared on the compression side under a load of 32 kg and the product was separated. The bending strength at this time is 60 Kg/
There was mrn'te, and the distortion was 0.36-t'. From FIG. 5, it can be seen that the hybrid prepreg of this comparative example has a strength (point Y) below the hybrid rule (line ED). An alumina fiber prepreg was produced in the same manner as in Example 1 except that only the alumina fiber of Example 2 was used as the single-light reinforcing fiber, and a test was conducted in the same manner as in Example 1. As a result of the test, cracks appeared on the tensile side under a load of 78 kg, but no separation occurred. The bending strength at this time is 154
K g/m and the strain was 1.33. The hybrid prepreg according to the present invention configured as described above has a feature of increased compressive strength.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of a hybrid prepreg according to the present invention. FIGS. 2 and 3 are diagrams illustrating one method of manufacturing a hybrid prepreg according to the present invention. FIGS. 4 and 5 are graphs illustrating the hybrid compound rule of the hybrid prepreg according to the present invention. FIG. 6 is an explanatory diagram illustrating the test method. FIG. 7 is a schematic cross-sectional view of a conventional hybrid prepreg. 2: Carbon fiber thread 3: Carbon fiber section 4: Different type of fiber thread 5: Different type of fiber section 6: First mixed fiber region 7: Second mixed fiber region 8: Trix resin Figure 4 Nicalon VO (ratio ( %) Figure 2 Figure 3 Figure 5 2゜8゜oO Aluminum fiber; aVoL ratio (%) Figure 6

Claims (1)

[Claims] 1) A first mixed fiber region in which carbon fiber sections containing carbon fiber threads and dissimilar fiber sections containing one or more types of dissimilar fiber threads are arranged in alternating juxtaposition in one layer; A second mixed fiber region in which carbon fiber sections containing fiber threads and dissimilar fiber sections containing one or more types of dissimilar fiber threads are arranged side by side alternately is arranged such that different fiber sections are joined to each other. 1. A hybrid prepreg characterized in that the prepreg is formed in a layered manner and a matrix resin is impregnated between the fiber threads.