JPS6034509B2 - Manufacturing method of glass fiber-filled paperboard - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a glass fiber-containing glass fiber board.

In recent years, with the development of alkali-resistant glass fiber,
Glass fiber reinforced cement (GRC) has been attracting attention, and various methods of manufacturing GRC boards have been proposed.

Among these manufacturing methods, the papermaking method is an excellent manufacturing method that allows mass production, and many patent applications have been filed regarding its formulation, manufacturing method, and manufacturing apparatus. In this production method, many methods of supplying glass fiber have been proposed, including {i' mixing with cement in the most basic mixer, beater, etc., and (ii) pouring cement slurry and glass fiber into a vat. Separately supplied and mixed (JP-A-51-6951
(iii) Supplying glass fiber onto a cylinder roll and laminating it (Hakama Kaisho No. 52-5827), and supplying glass fiber onto a thin cement slope on endless felt (Samurai Kaisho No. 51-139815) etc. are already known.

The present invention relates to these improvements, and allows GRC boards with high strength to be obtained with good productivity by a papermaking method, and asbestos, pulp, A second glass fiber chopped strand is supplied to a cement slurry obtained by adding and mixing aggregates, additives, etc., the cement slurry is supplied to a vat, and the glass fiber-containing paper is made by cylinder rolls. This is a method of manufacturing a board.

The present invention has the advantage that it is easy to mass-produce glass fiber-filled paper sheets with high initial and long-term strength because the glass fibers are less damaged, and the glass fiber-filled paper sheets have uniform characteristics. A board is obtained.

In addition, a particular feature is that the chopped glass fiber strands are supplied in two parts, and the first chopped glass fiber strand (hereinafter referred to as the first glass fiber in the present invention) is supplied in the mixing process of cement, etc. By supplying and mixing at the same time and then supplying a second chopped glass fiber strand (hereinafter referred to as second glass fiber in the present invention) to the obtained cement slurry, some of the glass fibers are loosened. Also, since some of the chopped strands are mixed in as they are, the papermaking properties are good and peeling is difficult, and the strength is further improved because the glass fibers and cement bond well. Specifically, the present invention is used as follows.

Bortland cement is usually used as cement, to which asbestos, pulp, aggregate, and additives are added as necessary.From the viewpoint of paper-making properties, asbestos, pulp, or fibrillated synthetic fibers are used as cement. It is preferable to mix it with or dissolve it and mix it afterward, and the bone material may be mixed as long as it does not have an adverse effect on papermaking.

The various raw materials mixed in this way are mixed with a large amount of water to form a uniform cement slurry.

Specifically, it is preferred that the first glass fiber is incorporated in an amount of 20 to 40% of the total glass fiber chopped strand supply.

The first glass fibers supplied here are preferably those that are easily defibrated in water, that is, those that are easily dispersed into monofilaments, and are preferably glass fiber chopped strands using a sizing agent that is easily soluble in water.
In addition, from the viewpoint of adhesion to cement, it is preferable to use a filament with a small diameter, and it is sufficient to supply the filament in the form of a chopped strand with a length of usually 3 to 100 mm. The fine fiber diameter of the first glass fiber means that the filament of the first glass fiber should be thinner than the filament diameter of the second glass fiber. 3-2
It is sufficient to use one having a diameter of about 0.0 mm, preferably 7 to 15 mm. If a filament with poor dispersibility or/and a very thick filament is used in this process, it will be difficult to mix uniformly, and if mixing is performed with excessive force or for a long time,
The fibers are damaged and the strength of the manufactured GRC tends to decrease. The cement slurry mixed with the first glass fibers is stored in a storage tank as required, and then supplied in a constant quantity to a vat.

The second glass fiber is supplied between the mixing step and the step of supplying it to the vat, and at a stage after the storage tank, without being mechanically stirred.Since there is no forced mixing, the second glass fiber , the chopped strand continues to maintain its supplied form.

Since the second glass fibers supplied in this way are not forcibly mixed, they are usually transported in a layered state on top of the cement slurry, and are dispersed non-uniformly in the cross-sectional direction of the flow of the cement slurry (in some cases, However, the amount of chopped glass fiber strands and the amount of cement slurry supplied per unit time are uniformly distributed, and as these are supplied to the vat, , the glass fibers are uniformly dispersed by a fly in the vat.

This second glass fiber contributes to developing the strength of GRC, and preferably supplies 60 to 80% of the total glass fiber chopped strand supply amount.

In addition, in order to develop strength and reduce strength loss over a long period of time, this second glass fiber is preferably a chopped strand with a strength of 5 to 100, and a thick, water-resistant material that loosens into monofilament in water. It is preferable to use an excellent sizing agent, and it is preferable to use a filament having a relatively large diameter, specifically, a filament having a diameter of 10 to 40 mm, preferably 15 to 30 mm. This second glass fiber is usually one that tends to remain in an unrelaxed form as described above, and is subjected to long-term forced lasing in a highly concentrated cement slurry only by being stranded in a vat. Because GRC is not dispersed in the monofilament and is uniformly dispersed in the form of chopped strands, it is possible for GRC to develop high strength similar to manufacturing methods in which chopped strands of glass fiber are not defibrated, such as the direct spray method. be.

Furthermore, in the present invention, it is important to supply the second glass fibers onto the cement slurry before supplying the cement slurry to the vat, so that the second glass fibers and the cement slurry are conveyed in a separated state. However, the ratio of the second glass fiber to the cement slurry is always kept at a constant ratio, and since both are fed into the vat together, after being fed to the vat, there is a This means that the second glass fibers can be uniformly dispersed in the cement slurry with a forced sanding.

Further, it is also possible to apply a heat treatment to an extent that the second glass fibers do not loosen before being supplied to the vat. The glass fiber chopped strands and the cement slurry are thus dispersed in the vat, which is then rolled up using cylinder rolls, then transferred to endless felt, and wound around a making roll to a desired thickness to obtain a plate or tubular body.

Then, if necessary, the product is made into a GRC product through processing steps such as pressing and surface unevenness. Further, other chopped glass fiber strands may be supplied on this cylinder roll or endless felt, for example, in the form of chopped strands, roping, glass cloth, etc.

Next, examples of the present invention will be shown and explained. 8 parts by weight of Boltland cement, 5 parts by weight of asbestos, 2 parts by weight of pulp, 1 part by weight of the first glass fiber (chopped strand of 25 strands made of 204 filaments of 13 piles with a water-repellent sizing agent). A cement slurry is obtained by mixing with 6 times the volume of water in a pulper for 2 minutes and sent to a storage tank. 2 glass fibers (2
102 chopped strands of 0 french filaments gathered together with a water-insoluble sizing agent (25 parts long chopped strands) were supplied to cement slurry in an amount of 4 parts by weight based on 9 parts by weight of the solid content of the above mixture. I fed it to the bat without doing Azusa.

Here, the second glass fibers were transported on top of the cement slurry and were gradually and naturally mixed into the cement slurry, but at first they were completely separated. In the vat, the agitator installed at the bottom of the vat appears to be completely evenly dispersed with only the rope agitation. The raw seeds obtained were transferred to an endless felt and wound around a making roll 6 times to obtain a GRC with a thickness of 5.

Claims (1)

[Scope of Claims] 1. A second glass fiber is added to a cement slurry obtained by adding and mixing asbestos, pulp aggregate, additives, etc. as necessary to cement and the first chopped glass fiber strand. A method for manufacturing a glass fiber-containing sheet board, which comprises supplying chopped fiber strands, supplying the cement slurry to a vat, and then forming the sheet using cylinder rolls. 2. The method according to claim 1, wherein the ratio of first glass fiber chopped strand/second glass fiber chopped strand is 1/4 to 2/3. 3. Claim 1 or 2, in which the second chopped glass fiber strand is a chopped glass fiber strand that is more difficult to defibrate in water than the first chopped glass fiber strand. Method. 4 Claim 1, 2 or 3 in which a glass fiber chopped strand consisting of a thicker filament is used as the second glass fiber chopped strand than the first glass fiber chopped strand. the method of.