JPS5837151B2 - 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, in a method for producing inorganic fibers by using polyvinyl alcohol or a mixture of polyvinyl alcohol and starch as a binder and boric acid or its salt as a crosslinking agent, the inorganic fiberboard scraps obtained by such a method are used. The present invention relates to a method for producing an inorganic fiberboard, which is characterized in that it is treated in advance with an acidic liquid and the treated product is reused as a part of papermaking raw material in the coexistence of an anionic or nonionic surfactant.

Traditionally, inorganic fiberboards have been produced by mixing a mixture of rock wool with polyvinyl alcohol as a binder, or with other water-soluble organic polymer compounds such as starch, and boric acid or its salt as a crosslinking agent in a large amount of water. It is made by dispersing it in water, making it into paper, and then heating and drying it.

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 some of the fiberboard obtained in this way is reused as scrap, the binder (polyvinyl alcohol) remaining in the scrap becomes a water-insoluble composite by combining with the crosslinking agent. , it only exists as an organic component and cannot be used as a binder as it is.
Ino is the reality.

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 originally be non-twisted, resulting in an increase in the amount of smoke emitted in the event of a fire, and also an increase in the amount of heat generated by the inorganic fiberboard itself.

As a result of research conducted to improve the above-mentioned problems that occur when polyvinyl alcohol is used as a binder, the present invention has been developed by immersing the waste to be recycled in an acidic solution in advance and treating it with an acid. By reusing it as part of the papermaking raw material in the coexistence of a surfactant, the organic content (composite polyvinyl alcohol) remaining in the waste is restored to its binder function, and the performance is improved compared to when a new binder is used. It was discovered that scales can be recycled into inorganic fiberboard with no inferiority in terms of quality.

The solvent for the acidic liquid used in the present invention is preferably water, and the solute is not particularly limited as long as it exhibits acidity when dissolved or suspended.

For example, it may be an inorganic or organic acid such as sulfuric acid or phosphoric acid, an acidic acid when hydrolyzed such as aluminum sulfate or zinc sulfate, or an acidic acid when suspended such as certain clays.

As the surfactant added during recycled papermaking, either anionic or nonionic surfactants can be used, 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.

To regenerate inorganic fiberboard waste using the acidic aqueous solution and 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. Afterwards, the above-mentioned scraps treated with rock wool and an acid aqueous solution are dispersed to form a paper, and then the thickness is adjusted.
A recycled inorganic fiberboard is produced by drying in a dryer at 50 to 180°C.

As described above, a papermaking solution is prepared by dispersing or dissolving each raw material including recycling waste in water, but the organic content (polyvinyl alcohol borax composite) remaining in the inorganic fiberboard waste is acidic. It undergoes a decomposition reaction in an aqueous solution, changing from water-insoluble to water-soluble, and the surfactant added during papermaking relaxes the crystallized structure and imparts affinity, making it completely identical to the newly used binder (polyvinyl alcohol). It is thought that this behavior occurs.

There is no need to particularly limit the ratio of the amount of recycling waste to rock wool.

The amount ratio of the acidic aqueous solution is 200 to 1000 parts by weight per 100 parts by weight of recycled waste, and the hydrogen ion concentration is 6 or less, preferably 5 to 6.

The degree of acid treatment is not particularly limited, but preferably from room temperature to 40
It is ℃.

The amount of surfactant is 0.00 per 1000 parts by weight of paper-made water.
01 to 0.05 parts by weight.

Hereinafter, the present invention will be specifically explained with reference to Examples.

Example 1 A paper was made using 10,000 y of rock wool, 5 g of polyvinyl alcohol (PVAI17-HS manufactured by Kuraray) as a binder, and 5 g of borax as a crosslinking agent, and heated at 160° C. in a hot air dryer for 2 hours.
30.9 was collected as scrap from the inorganic fiberboard that had been dried for several hours, immersed in 150 g of an aqueous sulfuric acid solution with a hydrogen ion concentration of 5 for 5 minutes at room temperature, and drained using a decanting method.

On the other hand, 4.5 g of polyvinyl alcohol, 4.5 g of borax, and an anionic surfactant (Rapizol B-30 manufactured by NOF Co., Ltd.
) 0.0:l was dispersed or dissolved in 2000 g of water, and further 70 g of rock wool and 30 g of the acid-treated scraps were dispersed, and then the paper was made and dried in a hot air dryer at 160°C for 2 hours. , made of inorganic fiberboard with a thickness of 10 mm and a width of 20 mm.
, Sampling to a size between length 50 (Experiment/I64)
After conditioning the humidity at 20° C. and 65% RH, the surface hardness (using a thread-wound hardness tester) was measured.

For comparison, experiments (Experiments A6.1 to A6.3) were conducted on the presence or absence of acid treatment of inorganic fiberboard waste when reusing the waste, and the presence or absence of surfactant use during papermaking, and the results are also listed in Table 1. .

The results shown in Table 1 show that the recycled inorganic fiberboard produced by combining the acid treatment of the scraps of Experiment I64 of the present invention and the addition of a surfactant during papermaking exhibits excellent surface hardness.

Example 2 100 g of rock wool, 1 g of polyvinyl alcohol as a binder, 4 g of tapioca starch, 1 g of borax as a crosslinking agent, and 0.0 g of borax as a crosslinking agent.
30.9 was collected as scrap from the inorganic fiberboard produced by making paper using 25g and drying it at 160°C for 2 hours in a hot air dryer, and immersed it in 150g of a sulfuric acid aqueous solution with a hydrogen ion concentration of 5 for 5 minutes at room temperature. , and drained using the decanting method.

On the other hand, add 0.8 g of polyvinyl alcohol, 3.2 g of tapioca starch, 0.2 g of borax, and 0.02.9 g of anionic surfactant (Rapizol B-30 manufactured by NOF Co., Ltd.) to 200 g of water.
(From an inorganic fiberboard made by dispersing or dissolving in Pi', further dispersing 70 g of rock wool and 30 g of the scraps previously treated with acid, making a paper, and drying it in a hot air dryer at 160°C for 2 hours. Samples were taken at a size between 10 mm thick, 20 mm wide, and 50 mm long (experiment A67), and heated at 20°C and RH.
Surface hardness after humidity conditioning at 65% condition (according to a pincushion hardness tester)
was measured.

For comparison purposes when reusing inorganic fiberboard waste, experiments (experiments/165-6) were conducted with and without the use of acid-treated waste and with and without the addition of surfactants during papermaking, and the results are also listed in Table 2. .

The results in Table 2 show that when a surfactant is added during waste recycling as in Experiment A6.7 of the present invention, the organic content in the waste acts effectively as a binder.

Example 3 Rock wool 1 0 0 f! Polyvinyl alcohol (PVAI 1 7-HS manufactured by Kuraray) 5 as a binder.
g. Take 30 g of the inorganic fiberboard as scraps from a paper made using 5 g of borax as a crosslinking agent and dry it at 160°C for 2 hours in a hot air dryer, and add it to 150 g of a sulfuric acid aqueous solution with a hydrogen ion concentration of 5 at room temperature. The liquid was immersed for 5 minutes, and the liquid was drained using a decanting method.

On the other hand, 4.5 g of polyvinyl alcohol, 4.5 g of borax, and a nonionic surfactant (NOF Nonion E-2 3
0) Disperse or dissolve 3g of 0.0 in 2000g of water, add 70g of rough rock wool, and add the acid-treated scraps 3 (
After dispersing Bi', it is made into paper and heated to 160 ml in a hot air dryer.
℃ for 2 hours, and the resulting inorganic fiberboard has a thickness of 10 mm.
A sample (experiment, 469) L having a size of 1nrIL, width 20mm, and length 50mm was conditioned at 20° C. and RH 65, and then the surface hardness (using a pincushion hardness meter) was measured.

For comparison, an experiment (46.8) was conducted on the case where inorganic fiber board scraps were not treated with acid when they were reused, and the results are also listed in Table 3.

The results in Table 3 show that the recycled inorganic fiberboard produced by combining the acid treatment of waste in Experiment I6.9 of the present invention and the addition of a surfactant during papermaking exhibits excellent surface hardness. .

Claims (1)

[Claims] 1. In a method of papermaking and board making of inorganic fibers using polyvinyl alcohol or a mixture of polyvinyl alcohol and starch as a binder and boric acid or its salt as a crosslinking agent, the scraps of the inorganic fiberboard obtained by this method are acidified in advance. 1. A method for producing an inorganic fiberboard, which comprises treating the inorganic fiberboard with a liquid and reusing the treated product as part of a raw material for papermaking in the coexistence of an anionic or nonionic surfactant.