JPS6125666B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a GRC papermaking method for manufacturing glass fiber reinforced cementitious material (GRC) by a papermaking method. Conventionally, asbestos slate has been used for a variety of purposes due to its advantages of being thin, strong, and nonflammable, and its production has achieved high productivity through paper-making methods. In response to this, research has begun to apply glass fiber with excellent alkali resistance, which has been developed in recent years, to slate.
Many manufacturing methods, manufacturing devices, etc. have been proposed. Of these, most of the content regarding the production of GRC using the papermaking method has been published since 1975. For example, in JP-A No. 55317/1973, a part of asbestos was replaced with glass fiber, and glass fiber-reinforced asbestos was published. Slate is shown, and in JP-A-51-62811, GRC is made by mixing alkali-resistant glass fibers containing fibers with a fiber length of 1 mm or less at 5 wt% or more of the total fiber amount.
It has been shown that it is possible to make paper, and also, in JP-A-51-
No. 70222 also indicates that GRC can be made by mixing fibers with a fiber length of 1 mm or less and alkali-resistant glass fibers. However, JP-A No. 51-55317 requires asbestos, and there are issues of resource depletion of high-quality asbestos and asbestos pollution, and the other two cases take these into consideration.
Although the aim was to obtain asbestos-free GRC using man-made fibers, it was necessary to crush the fibers into lengths of 1 mm or less, which was a time-consuming process. In addition, there was also Japanese Patent Application Laid-Open No. 53-36526, which used both a glass filament and a glass strand. However, these asbestos-free formulations tended to have low strength. The present inventor aimed to obtain a GRC paper-formed product which can be made into paper even if it is asbestos-free and has high strength while preventing such drawbacks.
Glass fiber for diameter reinforcement 1-10wt%, 3μ or less,
Preferably fine glass fibers with a diameter of 2μ or less 1~
A cementitious material containing 10wt% is made into paper, and the desired
GRC-generated form, steam cured at 50℃ or higher
This is the GRC papermaking method. The most important feature of the present invention is that it is possible to greatly improve the strength of GRC produced by the papermaking method, which has conventionally achieved relatively low strength. In GRC using the conventional spray method, heat curing only accelerates the deterioration of the glass fibers and reduces their strength, whereas the paper made using the fine glass fibers of the present invention
In the case of GRC-formed bodies, by steam curing within the scope of the present invention, it was possible to improve the bending strength by as much as 20 to 80% with almost no change in impact strength. The present invention enables papermaking without asbestos, which eliminates the pollution problems associated with asbestos.GRC boards, which are stronger than conventional asbestos slates, can be used to improve the productivity of asbestos slate production. It has the advantage that it can be manufactured without significantly reducing the Further, in the present invention, the addition of valves can be done in a small amount or zero, so that the nonflammability of the paper-made GRC board is not impaired. Furthermore, in order to manufacture and use fine glass fibers, the process of processing the glass fibers once manufactured is unnecessary, except for the process of cutting the glass fibers to a desired length as necessary, and the manufacturing process is carried out by flame spraying. Even if there are by-products such as thick fibers and sharp glass pieces that are produced when the method is used, by mixing them with the cementitious material and making paper, they will be included in the manufactured GRC. This also has the advantage that no waste is generated unless these by-products are generated in large quantities. As the glass fiber in the present invention, the reinforcing glass fiber uses 0 to 10 wt% of alkali-resistant glass fiber with a diameter of 7 to 30μ, particularly 7 to 30μ.
It is preferable to use a chopped strand made by cutting 50 to 1000 glass filaments with a diameter of 30μ into 5 to 100 mm lengths.If the length is less than 5 mm, there will be little reinforcing effect, and if it exceeds 100 mm, it will become fluffy. This is not desirable because it is easy to stand up. This reinforcing glass fiber has a diameter of 7 μm or less, which requires a very large number of filaments to be bundled together to provide sufficient strength, and it is also susceptible to erosion by the alkaline components in cement, so it is generally not used. The reinforcing effect decreases, and conversely, if it exceeds 30 μm, the stiffness of the fibers increases, the fibers become fluffy, the compatibility with the cementitious material decreases, etc., and the reinforcing effect tends to decrease, which is not preferable. It is preferable for the reinforcing glass fiber to be mixed in at least 1 wt% for the reinforcing effect, and if it is less than 1 wt%, the impact resistance, which is a feature of GRC, tends to be insufficient. or,
On the other hand, if it exceeds 10wt%, it is undesirable as it tends to cause fuzzing of the fibers and delamination of the GRC board.
By setting it to 8wt%, the strength is high and the composition has good paper formability. The fine glass fiber is a filament of glass fiber having a diameter of 3 μm or less, preferably 2 μm or less, and specifically, glass wool or a cut glass filament can be used. It is preferable that this thin glass fiber is also made of alkali-resistant glass fiber so that peeling does not occur over a long period of time. When the diameter of these fine glass fibers exceeds 3μ, there is almost no improvement in paper formability, that is, a large amount of solids passes through the wire mesh of cylinder rolls, increases the solids content in waste water, lowers the butt level, and causes the winding of the making roll. This method tends to have disadvantages such as an increase in the number of strips and the possibility of peeling of the paper-formed GRC board. In particular, by setting the diameter to 2μ or less, the effect of preventing these problems becomes remarkable. Further, the average length of the fine glass fibers is 200 mm or less, preferably 2 to 100 mm, which improves paper-making properties since they bond well with cementitious materials. This fine glass fiber has a diameter of 3μ or less.
It contains up to 10 wt%, and if it is less than 1 wt%, the effect of improving paper formability is small, and if it exceeds 10 wt%, the improvement in paper formability tends to decrease. Furthermore, when glass wool is used as the fine glass fiber, since glass wool with a diameter of 3μ or more is produced and mixed at the same time, it is preferable to take out only those with a diameter of 3μ or less from among these. , 3 if the diameter is less than 7μ
Preferably less than 20wt%, including those less than μ
If the content is 12wt% or less, there will be almost no problems such as fuzzing or peeling even if the mixture is mixed. Of course, in this case as well, 1wt% or more of 3μ or less, preferably 2μ or less, preferably 2 to 2μ
8wt% is required. This fine glass fiber can, for example, contain 0.1
It can be produced by pouring it into a rod shape of ~1 mm and spraying it with a high-speed flame. Since the diameter of the fine glass fibers produced in this way generally ranges from 2 times to 1/3 times the average diameter (based on the number of fibers), 1 to 10 wt% of the fine glass fibers with a diameter of 3μ or less are included. Mix carefully. In particular, it is preferable to use fine glass fibers having a diameter of about 1 μm because of their good paper-making properties. Furthermore, the present invention provides that, as described above, the bending strength of a GRC formed body made from thin glass fibers can be significantly improved by vapor deposition at a temperature of 50°C or higher, preferably 50 to 90°C. It is. That is, whereas conventional GRC deteriorates due to accelerated heating and its strength decreases, the GRC manufactured according to the present invention can conversely improve its bending strength by steam curing. The reason why this effect occurs is unknown, but GRC produced by the papermaking method has traditionally had a lower strength development rate per amount of mixed glass fiber than GRC produced by the direct spray method, and the adhesion between the glass fiber and the cementitious material matrix has been However, according to the manufacturing method of the present invention, it is thought that the adhesion of the fine glass fibers is improved by steam curing. In addition, the total amount of these reinforcing glass fibers, fine glass fibers, and associated glass fibers having a diameter exceeding 3μ is 25 wt% or less, preferably 15 wt%.
The following shall apply. In other words, by setting the content to 25wt% or less, deterioration of surface properties such as fuzzing on the surface of the GRC board can be prevented.In particular, by setting the content to 15wt% or less, this effect is large and GRC with excellent paper formability and high strength can be obtained. be able to. Further, the cementitious material of the present invention is a single substance or a mixture of hydraulic cements such as Boltland cement, Roman cement, and alumina cement, and if necessary, slag, fly ash, gypsum, lime, pozzolan, and other fibers. Materials, resins, colorants, curing rate regulators, waterproofing agents, and other materials to which various aggregates and additives can be used within the range that do not adversely affect papermaking can be used. In addition, it is preferable that the valve is added in an amount of 0 to 5 wt%, which can improve the paper forming property.
% is not very desirable in terms of nonflammability and shrinkage of the GRC board. Asbestos may be added, but it should be kept at 5wt% or less because of its entanglement with fine glass fibers. Also, if there is a problem with pollution, etc., make sure that it does not get mixed in. The GRC compound blended in this way is made into a slurry with a solid content of 5 to 30 wt% by adding water.
The paper is supplied to one or more vats, rolled up by a cylinder roll, transferred to an endless felt, wound around a making roll, and formed into GRC plates, GRC pipes, etc. , Fourdrinier paper making method, and short wire paper making method can also be used. The GRC molded article thus formed is then steam-cured at 50°C or higher, preferably 50 to 90°C. If it is less than 50℃, curing will be insufficient and the strength will not improve much. If it exceeds 90℃, the glass fiber will tend to deteriorate and the strength will decrease, so steam curing should be done at 50 to 90℃. It is preferable. Note that this temperature only needs to be maintained at this temperature for the GRC molded body, and in some cases, the supplied steam temperature may be maintained at a higher temperature. The curing period may normally be about 1 to 30 days at 50 to 90°C, preferably a relatively long period of time at low temperatures, and a relatively short period of time at high temperatures. If the heating time is less than 1 day, there is an effect of accelerating curing, but hardly any effect of improving strength is obtained. On the other hand, steam curing for more than 30 days does not improve the strength improvement rate, and in some cases, the strength improvement may decrease or the strength may decrease, so it is not usually recommended as there is not much merit. will not be adopted. Further, from the viewpoint of developing strength, it is preferable that the GRC molded body is cured to a degree that does not cause deformation and then subjected to the steam curing of the present invention. The term "to the extent that no deformation occurs" as used herein means that the hardening is at least to the extent that plastic deformation does not occur under its own weight, and if the steam curing of the present invention is performed while plastic deformation occurs, the strength will be sufficiently increased. It may not occur. On the other hand, if a long curing time is allowed, there is no problem in terms of strength development, but productivity deteriorates. For this reason, the standard time is usually about 0.5 to 14 days; for example, when ordinary Portland cement is used, it is sufficient to curing at room temperature for about one day, followed by steam curing according to the present invention. In addition, pressure dehydration, short-time heat curing, various processing, pressing, etc. can also be applied. Further, part of the steam curing can be carried out in water at 50 to 90°C, and in this case, the total period may be 1 to 30 days. Of course, it may be cured for more than 30 days as long as the strength does not decrease. Next, a test example will be shown and explained. Each of the following examples uses 20μ as reinforcing glass fiber.
Chopped strands of alkali-resistant glass fibers (product name: "Alpha Iver" manufactured by Asahi Glass Co., Ltd.) manufactured by the flame blowing method as thin glass fibers (SiO ₂ 58wt%, ZrO ₂ 15wt%, CaO 5wt%,
The composition is Na ₂ O 18wt%, La ₂ O ₃ 3wt%, Na ₂ SO ₄ 1wt%, and the diameter shown in each table -10% to +20% accounts for 90wt% or more of the total). The paper was made using portland cement (ordinary portland cement made by Mitsubishi Mining Cement Co., Ltd.), pulp (softwood pulp), and asbestos (class 5 chrysotile asbestos), with a slurry concentration of 10 wt%, and a small paper machine with a diameter of 1. The samples were dehydrated and pressed at 80 kg/cm ² for 3 minutes, then pre-cured as shown in the table, and then cured according to the present invention. Then, it was left in air at room temperature for one week, and its bending strength and impact strength were measured. In addition, in each example, as a comparative example, each strength after curing at room temperature and in a humid air for 28 days was also measured and shown as the strength after curing at room temperature.

[Table] Examples 1 to 6 are examples of the present invention;
In particular, the bending strength was significantly improved. Further, in Example 7, the period of steam curing was short, and the improvement in strength was only insufficient. Example 8 is a case of asbestos slate, and there was virtually no change in strength. In this way, the present invention can significantly improve the strength of a GRC molded product by providing heating and curing, which was unthinkable in conventional GRC, and it is possible to form a GRC molded product even if it is asbestos-free. It is an excellent material that can generate strength, and can be used in various applications in the future.

Claims (1)

[Claims] 1. 1 to 10 wt% of reinforcing glass fibers with a diameter of 7 to 30 μm
and a GRC paper-making method in which a cementitious material containing 1 to 10 wt% of fine glass fibers with a diameter of 3μ or less is made into a paper, formed into a desired GRC molded body, and steam-cured at 50°C or higher. 2. GRC papermaking according to claim 1, wherein reinforcing glass fibers are blended in the form of chopped strands, and the fine glass fibers are blended in the form of cut pieces of glass wool or glass filament. Law. 3. The GRC paper manufacturing method according to claim 1, wherein the GRC molded body is steam-cured at 50 to 90°C for one day or more. 4 Claim 1, in which the GRC molded body is cured with steam at 50 to 90°C after being cured to the extent that it does not deform.
GRC paper manufacturing method described in section.