JPH0566842B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to fiber-reinforced inorganic boards used for structures used in the field of civil engineering and construction, particularly plate-like structures such as roofs, walls, floors, pits, etc. By using a reinforcing material that can effectively exhibit properties such as elastic modulus, the physical properties of the fiber-reinforced inorganic molded article are improved. [Prior Art] Various proposals have been made for fiber-reinforced inorganic boards, including fiber-reinforced inorganic boards in which short fibers as reinforcing materials are randomly oriented, and continuous fibers oriented in one or two directions and laminated. Fiber-reinforced inorganic boards are known (Kajima Construction Technology Research Institute Annual Report No.
No. 29, pages 81-88, and No. 30, pages 57-68: Japanese Patent Application Laid-Open No. 138647/1983). In a fiber-reinforced inorganic board, unless the adhesion strength between the reinforcing fibers and the binding material is insufficient, a reinforcing effect commensurate with the strength of the reinforcing material cannot be obtained. This problem is particularly important when using high strength reinforcements or fiber bundles. i.e. 80Kg
When carbon fibers with a low strength of about f/mm ² are used as short fiber monofilaments, the surface area of the fibers is larger than the cross-sectional area of the fibers, so the fibers may break when tensile stress is applied. It exerts a reinforcing effect until However, when using high-strength fibers or fiber bundles, the fibers fall out and a reinforcing effect commensurate with the original strength of the reinforcing fibers cannot be obtained. In order to improve this, it has been proposed that continuous high-strength fibers are made into a tangled fabric with strong intersecting force, impregnated with resin and hardened to form a reticulated molded body, and then placed in cement mortar (especially Kaisho 63-111045
No. 63-22636). However, the inherent tensile properties of textile fibers, i.e., tensile strength,
The current situation is that elastic modulus, etc., have not yet been fully utilized. [Problems to be Solved by the Invention] The present invention is a fiber-reinforced inorganic molded product that eliminates the drawbacks of conventional cement mortar molded products reinforced with entwined textiles and allows the original tensile properties of textile fibers to be better exhibited. The purpose is to provide the body. [Means for Solving the Problems] As a result of intensive study to solve the above problems, the present inventors found that the above problems could be achieved by using a special entwined fabric as described below. We have arrived at the present invention. The present invention provides a fiber-reinforced inorganic molded product which contains as a reinforcing material a reticular molded product which is a tangled fabric fixed with a resin in which each weft thread is entwined with a warp thread, and a fiber-reinforced inorganic molded product whose matrix is an inorganic hardening material. The body warp consists of two or more types of yarns with different stiffness, and at least one type of yarn with the highest stiffness has a warp bending degree C _w defined by the following formula (1) of 0.08.
A fiber-reinforced inorganic molded article characterized in that the weft bending degree C _f defined by the following formula (2) for the weft is less than 0.03 C _w = D _w /L _w (1) L _w : Adjacent Average distance between the wefts D _w : Average distance between one vertex of the waveform of the center line of the warp and a line connecting two adjacent vertices on the surface of the net-like molded body C _f = D _f /L _f (2) L _f : Average distance between adjacent warp threads D _f : In the cross section along the weft direction of the net-like molded body,
This is the average distance between one vertex of the waveform of the center line of the weft and a line connecting two adjacent vertices. That is, in the fiber-reinforced inorganic molded article of the present invention, the yarns and wefts, which have the highest stiffness among the warp yarns, are entangled and do not bend in the woven fabric and are almost straight. Then, the low-rigidity threads of the warp threads are entangled with the weft threads, thereby restraining the intersections of the warp threads and the weft threads. Before explaining the present invention, a conventional entwined fabric will first be explained below. In the weave of a conventional entwined fabric, a pair of warp threads 1, 1' are intertwined and bent, as shown in FIG. 2a. In addition, the weft thread 3 is subjected to force in the longitudinal direction by the weft threads 1 and 1', as shown in Fig. 2b.
Therefore, it is also bent. The reticular moldings conventionally used for cement mortars are made by fixing such entwined fabrics with resin. When this molded body is subjected to a load, the fibers are fixed with resin, so they do not straighten, and when the load increases, local distortion and stress concentration tend to occur at the bent part, and the original fiber strength is reduced to 100%. The inventors have discovered that breakage occurs at the bent portion before it is fully exerted. On the other hand, FIG. 1a and FIG. 1b show the case where the warp consists of two types of threads of the reticular molded body according to the present invention.
As shown in the figure. In the reticular molded body with reduced bending according to the present invention, a pair of wefts 1 and 2 have a high rigidity thread 1
In order to avoid bending of the high-rigidity fibers and maintain straightness, the high-rigidity yarn 1 is
are not substantially entangled, and the low-rigidity yarn 2 is entangled with 1. The high stiffness yarn 1 is therefore almost straight and is present on substantially one side of the tissue weave. On the other hand, the weft 3 is the 1st b
As shown in the figure, the warp threads 1 and 2 are subjected to almost no bending force in the longitudinal direction, so that they are also substantially straight. In the present invention, the warp and weft bending degrees C _w and C _f defined above represent the degree of bending of the warp and weft. This is shown in Figures 3a and 3b.
This will be explained with reference to the figures. In addition, in the figure, the bending of the yarn is exaggerated for clarity. It is assumed that FIG. 3a is an enlarged photograph taken from directly above, with the reticulated molding placed horizontally. First, the center line 4 of the highly rigid warp thread 1 and the center line 10 of the weft thread 3 are drawn. The apex of the center line 4 of the waveform is usually
This is the intersection of center line 4 and center line 10. In that case,
The distance D _w between one intersection 5 of lines 4 and 10 and a straight line 8 connecting adjacent intersections 6 and 7 is measured.
Next, measure the distance L _w between adjacent wefts, and calculate D _w /L _w
is calculated and taken as the degree of curvature of the warp (C _w ). Next, it is assumed that FIG. 3b is an enlarged photograph taken from directly above, with the reticulated molded body (cured with resin) cut along the weft direction and the cut surface placed vertically above. Draw the center line 11 of the weft 3, measure the distance D _f between one vertex 12 of the center curve 11 and the straight line 15 connecting the adjacent vertices 13 and 14, and divide by the distance L _f between the warp threads. The degree of curvature of the warp threads (C _f ) is determined by The distance L _f between the warp threads is the same for both the distance between the high-stiffness threads 1 and the distance between the low-stiffness threads 2. In the present invention, C _w and C _f are each an average value of values from at least 10 randomly selected locations. In the present invention, the degree of curvature of the warp C _w <0.08, preferably <0.05, and the degree of curvature of the weft C _f <0.03, preferably <
It is 0.01. In conventional entwined fabrics investigated by the present inventor, C _w is generally about 0.1 and C _f is about 0.08. In the present invention, the tensile properties of a net-like molded body obtained by fixing a tangled fabric with little bending with a resin as defined by C _w and C _f will be explained below. For this purpose, we use the concept of fiber strength utilization factor (F). The breaking strength A per fiber unit cross section is determined from the breaking strength obtained by pulling a reticular molded body sample (width 25 mm, length 150 mm) at a pulling speed of 20 mm/min. Divide A by the strength B per unit cross section of the raw material fiber from which the reticulated molded body was made. F (%) = A x 100/B In a tensile test of a reticular molded body hardened with resin, the bends (if any) of the threads in the tensile direction do not stretch and become straight, but break at the bends. It is thought that the resin itself has an extremely small contribution to tensile strength. Therefore, an F of 100% means that the original strength of the fibers used is fully utilized. The larger F, the less reinforcing material is required to achieve a given tensile property in a composite material using it. The strength utilization factor F of the reticulated molded body varies depending on the type of fiber, weaving method, and amount of resin, but in the conventional entwined fabric studied by the present inventor, F is approximately 50% when C _w is 0.12. be. According to the present invention, when C _w is 0.08, F is about 60%, and when C _w is 0.02, F is about 70-80%.
On the other hand, for the weft, when C _f is 0.08 as in the conventional case, F is about 40%. According to the invention, C _f is 0.03
When C f is 0.01, F is about 60%, and when C _f is 0.01, F is 70 to 80.
%become. In this way, the method of reducing the degree of bending of warp and weft yarns to below the above-mentioned values is to combine high-stiffness yarns and low-stiffness yarns in the entwined fabric used as a reinforcing material, and, if necessary, to By adjusting the tension during resin impregnation and curing, it is possible to reduce bending of the high-rigidity yarn and to entangle the low-rigidity yarn. On the other hand, by doing this, the force of the warp that tries to bend the weft is reduced, so the bending of the weft is also reduced. In addition, in the above, two types of threads are used as warp threads,
Although we have shown the case where a type of thread is used as the weft,
The present invention is not limited to this. For example, two or more threads can be used as the low-stiffness threads and intertwined. Two or more high-rigidity warp yarns may be used, each satisfying C _w <0.08, and entangled with low-rigidity yarns. It is also possible to use more than one history. The high-rigidity yarn used in the reticular molded body must have high strength, and examples thereof include carbon fiber, aramid fiber, high-tensile vinylon fiber, and alkali-resistant glass fiber. Since the low-stiffness yarn combined with the high-stiffness yarn is only expected to have the intersecting force of the fabric, it does not require much strength; carbon fiber, aramid fiber, high-tensile vinylon fiber, acrylic fiber, etc. It can be selected from a wide range of fibers such as polyamide fibers and polyester fibers. High-stiffness yarn and low-stiffness yarn are
Even if they are made of the same material, it is sufficient that they have different cross-sectional areas (for example, different filament numbers and fiber diameters) and different stiffnesses as yarns. Note that, for example, when a cement component is used as the inorganic material matrix, the yarn needs to have alkali resistance. In this way, it is easy to select appropriate fibers depending on the blending conditions of the inorganic material matrix. The weave density of entwined fabrics is generally coarse. For example, when cement containing aggregate is used as the inorganic material matrix, the openings are set at 3 to 50 mm, taking into account that the particle size of the aggregate (2 to 25 mm) can pass through the reticulated molded body.
It is desirable to set the interval preferably to about 3 to 10 mm. The resin for fixing the entwined fabric is impregnated into the fabric by suitable means such as dipping, spraying, etc. It is preferable to use a known prepreg manufacturing apparatus. As the resin, thermosetting resins are preferred, and specific examples include epoxy resins, urethane resins, phenolic resins, and polyimide resins. If cement is present as a component of the inorganic material used as the matrix, it is desirable that it has long-term durability against alkalinity, and that its strength does not deteriorate even after autoclave curing at 180℃ for about 5 hours. is preferred. The impregnated resin is subjected to heat curing treatment, but since this is done to maintain the shape of the fabric, it is necessary to at least put it in the so-called C stage state where the resin does not flow, and it is not necessarily possible to completely cure it. Not necessary. However, due to product stability,
It is preferable that the curing progresses as much as possible. The inorganic hardening materials used to construct the matrix in the present invention include ordinary cements such as Portland cement, alumina cement, and blast furnace cement, crushed calcium silicate-based compounds consisting of calcareous and silicic acids, and gypsum (hemihydrate gypsum). , anhydrous gypsum, etc.), granulated slag-based hydraulic materials such as blast furnace slag and a mixture of pulverized granulated slag and gypsum, and water, as well as natural or artificial aggregate (granular type: 2 to 25 mm), an admixture, and an admixture obtained by kneading the admixture. The entwined fabric obtained as described above is reinforced at the position where tensile stress is applied to the molded product, and
A matrix material is poured and cured to obtain a fiber-reinforced inorganic molded body. Depending on the target strength of the molded product, the strength, elastic modulus, number of filaments, etc. of the high-rigidity fiber to be used may be determined, and the type of fiber may be selected. As the molded article of the present invention, a plate-shaped article in which a net-like molded body is embedded near the surface is particularly preferable. By using the entwined fabric of the present invention, it is possible to improve the strength and rigidity of the fiber-reinforced inorganic molded product, or to reduce the amount of fibers in the reticulated molded product used as a reinforcing material. [Example] Example 1 Carbon fiber bundle with a tensile strength of 460 Kgf/mm ² as a high-rigidity fiber in a set of warps [6000 and 12000 filaments (single yarn warp 7 microns), hereinafter 6k and 12k
fil] is aramid fiber as a low-rigidity yarn.
Gebler 29 (400 denier) was used. The same carbon fiber bundle (12k fil) as above was used as the weft. Under the condition that the weave density is 3.3 threads/25mm for both warp and weft,
A tangled fabric having the structure shown in FIGS. 1a and 1b was produced. This fabric was impregnated with an epoxy resin liquid having the following formulation, and dried and cured at 150°C for 15 minutes. The amount of resin was 41% based on the weight of the cured reticulated mold. Table 1 shows the bending degree and utilization rate of the reticular molded body thus obtained. Bisphenol A type epoxy resin (GY-260,
Ciba Geigy) 100 parts dicyandiamide 10 parts imidazole type accelerator (Ciba Geigy)
2P4MHZ, Shikoku Kasei Co., Ltd.) 2 parts Solvent (methyl cellosolve) 120 parts

[Table] The obtained net-like molded body was cut into pieces of 40 mm x 160 mm so as to include four warps or wefts, and reinforcement was arranged so as to be located at the bottom surface of the form. The matrix material with the following composition was weighed and kneaded to obtain a matrix paste, which was then poured into a form and molded to obtain a bending test piece (dimensions: width 40 mm, length 160 mm).
mm, thickness 6mm). The obtained molded body was placed in water at 20℃.
It was cured for 14 days. Matrix composition: Ordinary Portland cement: 100 parts by weight No. 8 silica sand: 50 parts by weight Water: 50 parts by weight The strength test was conducted with the four warps or wefts in the test piece in the tensile direction. i.e.
A four-point bending test was conducted at a loading rate of 0.5 mm/min and a distance between supports of 40 mm. Furthermore, for comparison, a net-like molded body was produced in the same manner as above using conventional threads as shown in Table 2.
A similar bending test piece was prepared and a strength test was conducted.

[Table] The bending load-displacement curve obtained in the strength test is
As shown in the figure. The four curves 21, 22, 25 and 26 in the figure correspond to the following. 21... Tangled fabric of the present invention with the warp in the tension direction 22... Tangled fabric of the present invention with the weft in the tension direction 25... Conventional entwined fabric with the warp in the tension direction 26... Conventional entangled fabric The maximum breaking load values in Figure 4 are shown in Table 3, with the weft in the tensile direction.

〔Effect of the invention〕

According to the present invention, the bending strength and bending rigidity of the fiber-reinforced inorganic molded article are improved, the tensile strength and elastic modulus of the reinforcing fibers are effectively exhibited, and as a result,
It becomes possible to reduce the amount of reinforcing fiber added.

[Brief explanation of the drawing]

Figures 1a and 1b are plan and cross-sectional views of an example of a leash fabric according to the invention. 1...High rigidity warp thread, 2...Low rigidity warp thread, 3
...Weft yarn. Figures 2a and 2b are a plan view and a cross-sectional view of a conventional entwined fabric. 1, 1'...High rigidity weft thread, 3...Weft thread. FIG. 3a is an explanatory diagram of a method for measuring the degree of bending of warp threads. 1...High rigidity warp thread, 2...Low rigidity warp thread, 3
...Weft thread, 4... Center line of high rigidity warp thread, 5...
...A vertex of the waveform of the center line, 6, 7...Adjacent vertices of the waveform of the center line, 8...A straight line connecting 6 and 7. FIG. 3b is an explanatory diagram of a method for measuring the degree of bending of a weft yarn. 1...High rigidity warp thread, 2...Low rigidity warp thread, 3
...Weft thread, 11... Center line of high rigidity weft thread, 1
2... Vertex of the center line waveform, 13, 14... Adjacent vertices of the center line waveform, 15... Straight line connecting 13 and 14. FIG. 4 is a load-displacement curve in a bending test of a reticular molded reinforced inorganic plate. 21... A tangled fabric of the present invention with the warp in the tension direction, 22... A tangled fabric of the present invention with the weft in the tension direction, 25... A conventional tangled fabric with the warp in the tension direction, 26... A conventional entwined fabric with the weft in the tension direction.

Claims (1)

[Scope of Claims] 1. A fiber-reinforced inorganic molded product containing as a reinforcing material a reticulated molded product which is a tangled fabric fixed with a resin, in which each weft thread is entwined with a warp thread, and an inorganic hardened material is used as a matrix. , the warp of the net-like molded body consists of two or more types of threads with different stiffness,
The warp bending degree C _w defined by the following formula (1) for at least one type of yarn with the highest stiffness among them is
A fiber-reinforced inorganic molded article characterized in that the weft bending degree C _f defined by the following formula (2) for the weft is less than 0.03. C _w = D _w /L _w (1) L _w : Average distance between adjacent wefts D _w : Average distance between one vertex of the waveform of the center line of the warp and a line connecting two adjacent vertices on the surface of the net-like molded body C _f = D _f /L _f (2) L _f : Average distance between adjacent warp threads D _f : In the cross section along the weft direction of the net-like molded body,
The average distance between one vertex of the waveform of the weft centerline and the line connecting two adjacent vertices.