JPS5837150B2 - Manufacturing method of inorganic fiberboard - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing an inorganic fiberboard.

More specifically, polyvinyl alcohol or a mixture of polyvinyl alcohol and starch is used as a binder,
In a method for producing inorganic fiberboard, which involves papermaking and manufacturing inorganic fibers using boric acid or its salt as a crosslinking agent, the inorganic fiberboard scraps obtained by this method are treated with an anionic or nonionic surfactant. This relates to a method for producing inorganic fiberboard, which is characterized in that it is reused as part of the raw material for papermaking, and its purpose is to produce inorganic fiberboard, including the above-mentioned effective method for recycling inorganic fiberboard waste. To provide a manufacturing method.

In general, inorganic fiber boards are made by dispersing, for example, a mixture of rock wool, polyvinyl alcohol as a binder, or a mixture of polyvinyl alcohol and other water-soluble polymers such as starch, and boric acid or its salt as a crosslinking agent in a large amount of water. After papermaking, it is heated and dried.

In this drying process, polyvinyl alcohol dissolves due to temperature rise and undergoes a crosslinking reaction with boric acid or its salt, and the resulting composite firmly adheres to the inorganic fibers and, together with progress of crystallization due to heat treatment, forms the resulting inorganic fibers. The water and moisture resistance of the board has been improved.

However, when a part of the fiberboard obtained in this way is recycled as scrap, the binder (polyvinyl alcohol) remaining in the scrap combines with the crosslinking agent to form a water-insoluble composite. The reality is that it simply exists as an organic substance and cannot be used as a binder as it is.

Therefore, in order to satisfy the mechanical properties such as hardness as an inorganic fiberboard, it is necessary to supplementally add a binder and a crosslinking agent corresponding to this composite.

This affects the heat resistance of the inorganic fiberboard, which should be essentially nonflammable, resulting in an increase in the amount of smoke emitted in the event of a fire, and an increase in the amount of heat generated by the inorganic fiberboard itself.

The present invention was developed as a result of research to improve the above-mentioned problems that occur when polyvinyl alcohol is used as a binder.
By restoring the function as a binder to the organic content (crosslinked polyvinyl alcohol) remaining in the waste, it is possible to obtain an inorganic fiberboard with performance no inferior to that of a case made only of a new binder. This is what I found.

In the present invention, both anionic and nonionic surfactants can be used as the surfactant, and these can be used alone or in combination.

Suitable anionic surfactants include dioctyl sulfosuccinic acid sodium salt, dodecylbenzenesulfonic acid sodium salt, and higher alcohol sulfuric acid ester sodium salt.

Suitable nonionic surfactants include polyoxyethylene oleyl ether, polyoxyethylene alkyl allyl ether, and polyethylene glycol monostearate.

Cationic surfactants may be used in combination as long as the purpose of the present invention is not impaired, but cationic surfactants that coagulate and precipitate polyvinyl alcohol are not preferred.

In order to regenerate inorganic fiberboard waste using the surfactant described above, a binder and a crosslinking agent are dispersed in paper-made water in which an anionic surfactant or a nonionic surfactant is dissolved, and then the rock wool and the fibers are dispersed. After dispersing the board waste and forming the paper, the paper is pressurized and thickened, and dried in a dryer at 1.50 to 180°C to produce a recycled inorganic fiberboard.

As described above, each raw material including waste for recycling is dispersed or dissolved in water to prepare a papermaking solution, but the organic content (crosslinked polyvinyl alcohol) remaining in the waste becomes surface active during heat drying. It is thought that the compound of polyvinyl alcohol and boric acid or its salt becomes hydrophilic, and behaves exactly the same as the newly used binder (polyvinyl alcohol). It will be done.

Note that there is no particular need to limit the ratio of the amount of recycling waste to rock wool.

Surfactant: 0.0001 parts by weight per 1000 parts by weight of paper-made water
~0.05 parts by weight.

The present invention will be specifically described below with reference to Examples.

Example 1 100 g of rock wool, 5 g of polyvinyl alcohol (PVA117-HS manufactured by Kuraray) as a binder,
30g from an inorganic fiberboard made by making a paper using 5g of borax as a crosslinking agent and drying it in a hot air dryer at 160°C for 2 hours.
was collected as scrap.

4.5 g of polyvinyl alcohol, 4.5 g of borax, and anion activator (NOF Rapizol B-30) 0
．． After dispersing or dissolving 2 g of 0.0 in water 2001, and further dispersing 70 g of rock wool and the fiberboard scraps, the paper was made and dried in a hot air dryer at 160°C for 2 hours. A sample with a width of 20 mm and a length of 5 mm was sampled (Experiment A3) L. After conditioning the sample at 20°C and 65% RH, the surface hardness (using a pincushion hardness tester) was measured.

For comparison, a case in which no waste was used (Experiment A6.
1) and the case in which no surfactant was added at the time of waste recycling (experiment/l62) were also conducted, and the results are also listed in Table 1.

From Table 1, it can be seen that when a surfactant is added at the time of scrap recycling as in Experiment/i63 of the present invention, the organic content in the scraps effectively acts as a binder.

Example 2 100 g of rock wool, 1 g of polyvinyl alcohol as a binder, 4 g of tapioca starch, and 0.2 borax as a crosslinking agent.
3 (1) was collected as scrap from an inorganic fiberboard produced by drying 5 g of the inorganic fiber board at 160° C. for 2 hours in a hot air dryer.

Polyvinyl alcohol o. sg and tapioca starch 3.
2g and borax 0. 2 g and 0.0 g of anionic activator (Nippon Oil Co., Ltd. Rapizol B-30) and 2000 g of water.
After dispersing or dissolving 70 g of rock wool and the fiberboard waste, it was made into a paper and heated in a hot air dryer at 160°C.
, 10mm thick from inorganic fiberboard dried for 2 hours.
Samples (experiment A6) L were taken to have a width of 20 mm and a length of 50 mm, and the surface hardness (using a pincushion hardness tester) was measured after conditioning the samples at 20° C. and 65% RH.

For comparison, experiments were also conducted in the case where no waste was used at all (Experiment 44) and when no surfactant was added at all when recycling the waste (Experiment A65), and the results are also listed in Table 2.

From Table 2, it can be seen that when a surfactant is added during waste recycling as in Experiment A66 of the present invention, the organic components in the waste act effectively as a binder.

Example 3 30 g of rock wool 10 (30 g was collected as scrap from an inorganic fiberboard made by making a paper using 5 g of polyvinyl alcohol as a binder and 5 g of borax as a crosslinking agent in Bi' and drying it in a hot air dryer at 160'C for 2 hours) did.

4.5g of polyvinyl alcohol, 4.5g of borax, and 0.02g of nonionic activator (Nonion NS-210 manufactured by NOF Corporation)
Disperse or dissolve g in 2000 g of water, and add 7 g of rock wool.
After dispersing 0g and the fiberboard waste, the paper was made and dried in a hot air dryer at 160°C for 2 hours.The resulting inorganic fiberboard was then sampled to a size of 10mm thick, 20mm wide, and 50mm long. (Experiment/169) and heated it at 20°C, RH65
After conditioning the humidity under conditions of %, the surface hardness (using a pincushion hardness meter) was measured.

For comparison, the case where no waste was used (Experiment A67)
) and the case where no surfactant was added at the time of waste recycling (experiment A8) were also conducted, and the results are also listed in Table 3.

Claims (1)

[Claims] 1. A method for manufacturing an inorganic fiberboard, which comprises forming inorganic fibers using boric acid or a mixture of polyvinyl alcohol and starch as a binder and boric acid or its salt as a crosslinking agent,
A method for producing an inorganic fiberboard, which comprises reusing inorganic fiberboard waste obtained by such a method as part of a papermaking raw material in the coexistence of an anionic or nonionic surfactant.