JPH03897A - Production of flame-retardant paper or flame-retardant board - Google Patents

Abstract

PURPOSE:To obtain the title paper and board having excellent flame retardance in improved yield without using an organic yield-improving agent, etc., exerting bad influence on the flame retardance by making slurry containing cellulose fiber, watercontaining inorganic compound and glass fiber at a specific ratio into paper. CONSTITUTION:Slurry containing 5-60wt.%, preferably 10-40wt.% cellulose fiber as solid content, 15-94wt.%, preferably 40-90wt.% water-containing inorganic compound (preferably aluminum hydroxide, magnesium hydroxide, gypsum 2 hydrate or calcium aluminate) as solid content and 0.05-80wt.%, preferably 0.1-40wt.% glass fiber having <=4mum diameter as solid content is made into paper to provide the aimed paper and board.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Branch] The present invention relates to a method for producing flame retardant paper or flame retardant board, and more particularly, the present invention relates to a method for manufacturing flame retardant paper or board.
A slurry containing glass fibers of μm or less is prepared and paper is made by a normal paper making method,
The present invention relates to a method for producing flame-retardant paper or flame-retardant board that has a high yield of hydrous inorganic compounds and excellent flame retardancy.

[Background Art] In recent years, as buildings become taller, larger, and more concentrated, fire retardancy and fire prevention measures are becoming more important.

BACKGROUND ART Flame-retardant paper or flame-retardant board, which imparts flame retardancy to various building materials, have traditionally been used to make buildings flame-retardant and to prevent fires.

Conventional flame-retardant paper or boards of this type generally include those whose main component is asbestos fiber, those treated with flame-retardant chemicals, or those containing large amounts of aluminum hydroxide powder. Are known.

Materials whose main component is asbestos fibers are made by mixing asbestos fibers with a small amount of cellulose fibers.

In addition, those treated with flame retardant chemicals may contain organic phosphorus compounds, phosphorus-containing nitrogen-containing organic compounds, sulfamates, inorganic phosphates, halogen-containing compounds, and antimony compounds, or a combination thereof. It is contained in paper or board by adding it internally to cellulose fibers or impregnating or coating it after papermaking.

Furthermore, paper or board manufactured by containing a large amount of aluminum hydroxide powder has a gibbsite crystal structure, and the aluminum hydroxide that is commonly used has a gibbsite crystal structure,
Since the crystal water is dehydrated at °C, it exhibits excellent flame retardant effects, there is no worry of toxic gas or smoke, and there are no hygiene issues such as handling or pollution, so it is currently safe. It can be said to be burnt paper or flame retardant board.

[Problems to be Solved by the Invention] However, while the above-mentioned materials containing asbestos fiber as a main component have the advantage of exhibiting excellent flame retardancy, asbestos fiber is designated as a specified substance, recent years,
Since it was found to be a causative agent of lung cancer, its use has been severely restricted from the viewpoint of pollution prevention and work environment hygiene, and its use is currently prohibited in some countries.

Moreover, paper or board manufactured by applying flame retardant chemical treatment has the problem that it tends to yellow when the content of flame retardant increases, and also causes significant discoloration when heated, leading to a decrease in commercial value. In addition, it produces toxic gas when ignited,
This creates smoke and poses a major safety problem.

In this regard, although paper or board manufactured by containing a large amount of aluminum hydroxide powder has the various advantages mentioned above, slurry containing a large amount of water-containing inorganic compounds such as aluminum hydroxide has poor water retention performance. If the water in the slurry is insufficient and is fed onto a papermaking mesh, the water in the slurry will be filtered and dehydrated through the mesh in a short period of time, and the dehydration process will be rapid.
There is a drawback in that the water-containing inorganic compounds in the slurry also tend to flow down the papermaking net together with the water.

This tendency becomes even more pronounced when a small-diameter hydrous inorganic compound is applied to improve the surface smoothness of flame-retardant paper or flame-retardant boards.

At present, it is technically very difficult to obtain a high yield by fixing a water-containing inorganic compound in paper or board. In order to solve this problem, various organic retention aids have been used, or SBR, NBR, acrylic latexes, etc. have been added.

However, adding these organic auxiliaries has a negative effect on flame retardancy, so instead of using these organic auxiliaries, it is preferable to add hydrated inorganic compounds such as aluminum hydroxide to the paper or board. There has been an urgent need to develop a manufacturing method for flame-retardant paper or flame-retardant board that can be produced at high yields.

The present invention was made to solve the above problems,
The object of the present invention is to provide a method for rationally and effectively producing flame-retardant paper or flame-retardant board that has a high yield of hydrous inorganic compounds and excellent flame retardancy.

[Means for Solving the Problems] The method for producing flame-retardant paper or flame-retardant board according to the present invention comprises cellulose fibers in a solid content of 5 to 60% by weight, a water-containing inorganic compound in a solid content of 15 to 94% by weight, The method is characterized in that a slurry containing glass fibers having a diameter of 4 μm or less in a solid content of 0.05 to 80% by weight is prepared and then made into paper.

Examples of the above-mentioned hydrated inorganic compounds include aluminum hydroxide, magnesium hydroxide, calcium hydroxide, gypsum dihydrate, and calcium aluminoxide. All of these compounds have water of crystallization in their molecules and have chemically similar structures. In addition, although there are some differences in decomposition temperature and endothermic amount depending on the type of hydrated inorganic compounds, they are completely common in that they decompose when heated to high temperatures and exhibit a flame retardant effect due to endothermic action. Therefore, basically any of the above-mentioned hydrous inorganic compounds may be used, but aluminum hydroxide is most suitable when considering economical efficiency such as acquisition price.

The content range of glass fibers having a diameter of 4 μm or less in the slurry according to the present invention is 0.05 to 80% by weight, preferably 0.1 to 40% by weight in terms of solid content. Its content is 0.05
If it is less than % by weight, the effect of improving the water retention performance in the slurry and the effect of improving the retention of water-containing inorganic compounds cannot be sufficiently obtained. Conversely, if the content exceeds 80% by weight,
Due to the insufficient amount of cellulose fibers, flame retardant paper or board with sufficient strength cannot be obtained.

The content of the water-containing inorganic compound ranges from 15 to 94% in terms of solid content.
The weight percent is preferably 40 to 90 weight percent. If the content is less than 15% by weight, sufficient flame retardancy cannot be obtained. On the other hand, if it exceeds 94% by weight, the amount of water-containing inorganic compounds will be too large, making it impossible to obtain flame-retardant paper or flame-retardant board with sufficient strength.

The content of cellulose fibers ranges from 5 to 60% by weight, preferably from 10 to 40% by weight, based on solid content. If the content is less than 5% by weight, sufficient strength cannot be obtained;
If the amount exceeds 20%, it is impossible to obtain flame-retardant paper or flame-retardant board with sufficient flame retardancy due to the excessive amount of organic substances.

A slurry containing cellulose fibers, a hydrous inorganic compound, and glass fibers with a diameter of 4 μm or less can be prepared as follows.

(2) A predetermined amount of glass fibers having a diameter of 4 μm or less or a predetermined amount of the dispersion is added to a predetermined amount of the cellulose fiber dispersion and mixed by stirring. Next, a predetermined amount of a water-containing inorganic compound or its dispersion is added to the dispersion thus obtained and mixed with stirring to obtain a desired slurry.

(2) A predetermined amount of cellulose fibers and glass fibers with a diameter of 4 μm or less are simultaneously dispersed, and a predetermined amount of a hydrous inorganic compound or its dispersion is added and stirred to obtain a desired slurry.

(2) A predetermined amount of a hydrous inorganic compound or its dispersion is added to a predetermined amount of a cellulose fiber dispersion and mixed by stirring. Next, a predetermined amount of glass fibers having a diameter of 4 μm or less or a dispersion thereof is added to the dispersion thus obtained, and the mixture is stirred and mixed.
Obtain the desired slurry.

(2) A predetermined amount of a water-containing inorganic compound or its dispersion is added to a predetermined amount of a glass fiber dispersion having a diameter of 4 μm or less, and the mixture is stirred. Next, a predetermined amount of cellulose fibers or a dispersion thereof is added to the dispersion thus obtained and mixed by stirring.
Obtain the desired slurry.

In the method for preparing the slurry described above, the method and order of addition of the cellulose fibers, the hydrous inorganic compound, and the glass fibers with a diameter of 4 μm or less are arbitrary, and beating treatment or the like may be performed as necessary.

Furthermore, the slurry according to the present invention may contain inorganic fibers such as carbon fibers and rock wool fibers, various synthetic fibers such as nylon, polyester, and polypropylene, synthetic resins, or synthetic dyes for coloring, as necessary. good.

Furthermore, the retention of water-containing inorganic compounds can be further improved by blending various organic retention improvers or SBR, NBR, acrylic latex, etc. with the slurry according to the present invention, if necessary.

Furthermore, depending on the application, dry and wet paper strength enhancers, sizing agents, waterproofing agents, etc. may be added to the slurry according to the present invention in order to improve the mechanical strength and post-processing suitability of flame-retardant paper or flame-retardant board. Needless to say, they should be combined.

In order to manufacture the flame retardant paper or flame retardant board according to the present invention using the slurry thus obtained, that is, the slurry containing cellulose fibers, a hydrous inorganic compound, and glass fibers with a diameter of 4 μm or less, a normal papermaking method can be used. Bye.

That is, a slurry containing cellulose fibers, a water-containing inorganic compound, and glass fibers with a diameter of 4 μm or less is supplied onto a paper-made mesh such as a regular fourdrinier, circular mesh, or inclined mesh, filtered and dehydrated, and then compressed and dried. A flame retardant paper or a flame retardant board having the desired flame retardancy can be obtained by this method. If necessary, 24 or more paper layers may be stacked using various combination nets, multi-tank circular nets, various laminators, etc. Furthermore, depending on the application, the resulting flame-retardant paper or board may be subjected to surface treatments such as spraying or coating with various paints or printing, or may be laminated with decorative boards, leather, synthetic resin films, etc. Needless to say, the added value of the flame retardant paper or board can be further increased.

The flame retardant paper or flame retardant board according to the present invention exhibits excellent flame retardancy because it contains a hydrous inorganic compound and glass fibers with a diameter of 4 μm or less, but this does not prevent the use of conventional flame retardants in combination. do not have.

Examples of flame retardants that can be used in combination include known flame retardants such as organic phosphorus compounds, phosphorus-containing nitrogen-containing organic compounds, sulfamine compounds, inorganic phosphates, halogen-containing compounds, and antimony compounds.

The flame retardant can be used by adding it internally to a slurry containing cellulose fibers, a hydrous inorganic compound, and glass fibers with a diameter of 4 μm or less, or by impregnating or coating it during or after the papermaking process and incorporating it into paper or board. Examples of methods include: However, in this case, it is natural that the content of the flame retardant should be determined in consideration of the content of the hydrated inorganic compound and the glass fiber with a diameter of 4 μm or less. Although the details of the mechanism of improving the water retention performance of slurry and the retention of water-containing inorganic compounds in paper or board are still unknown, the physical and chemical interactions between cellulose fibers and glass fibers are unknown. This is thought to be due to the physical and chemical interactions between cellulose fibers, glass fibers, and water-containing inorganic compounds. That is, the diameter of the glass fiber is 4μ
m or less, a three-dimensional composite network structure of cellulose fibers and glass fibers is generated, just like a crosslinked structure in a synthetic polymer. This three-dimensional composite network structure envelops the water-containing inorganic compound, creating a strong bond between the cellulose fibers, glass fibers, and the water-containing inorganic compound. The inorganic compound loses its ability to follow the hydrodynamic flow action and is fixed in a three-dimensional composite network structure composed of cellulose fibers and glass fibers. It provides appropriate resistance on the papermaking net, improves the water retention performance of the slurry containing a large amount of hydrated inorganic compounds, and also improves the fixation effect of the hydrated inorganic compounds in the three-dimensional network structure of cellulose fibers and glass fibers, and this hydraulics. The effects of reducing the filtration and dehydration effects are synergistic with each other, and as a result, the water-containing inorganic compound is absorbed into the paper or board, resulting in a unique synergistic effect. It is thought that some chemical action is also involved.

[Examples] Next, the present invention will be explained in more detail based on the following examples.

Each item in this example was measured by the following method.

■Yonetsubo: According to JIS P-8118.

■Thickness and density: According to JIS P-8118.

■Flame retardancy: Based on UL94 standard V-O.

■ Freeness: According to JIS P-8121.

■ Yield of hydrated inorganic compounds: by.

(Preparation of cellulose fiber dispersion) A commercially available softwood-based bleached sulfate bulb was difficult to break and beaten using a test beater to obtain a solution with a concentration of 1.40% by weight and a freeness of 225mf2.
A cellulose fiber dispersion liquid (C3F) was obtained.

Next, a commercially available softwood bleached sulfate bulb was disintegrated using a disintegrator to obtain a concentration of 1.38% by weight, freeness of 710m, and I2C3.
A cellulose fiber dispersion (2) named F was obtained.

Example 1 Glass fibers with a diameter of 0.65 μm (hereinafter abbreviated as glass fiber α) were added to 1045 g of cellulose fiber dispersion at 0°37
Then, 454.625 g of water was added and mixed with stirring using a disintegrator to obtain a mixed dispersion A of cellulose fibers and glass fibers α having a total content of cellulose fibers and glass fibers α of 1% by weight.

Aluminum hydroxide powder was added to 125 g of mixed dispersion liquid A and had an average particle size of 3.6 μm. 8 gt (the same applies hereinafter) was added, sufficiently dispersed and mixed using a stirrer, and hand-made using a Juken-type test paper machine to obtain paper a containing a hydrous inorganic compound.

Regarding hydrated inorganic compound-containing paper a, tsubo, thickness, density,
The yield and flame retardance of the hydrated inorganic compound were measured, and the results are shown in Table 1 and Figure 1.

Examples 2 to 5 In Example 1, 1018 g of cellulose fiber dispersion ■
When 0.75g of glass fiber α is added to (Example 2)
, or when 1.5 g of glass fiber α was added to 964 g of cellulose fiber dispersion ■ (Example 3), or when 3.7 g of glass fiber α was added to 804 g of cellulose fiber dispersion ■
The total amount of cellulose fiber and glass fiber α was prepared in the same manner as in Example 1, except when 5 g of glass fiber α was added (Example 4) or when 7.5 g of glass fiber α was added to 536 g of cellulose fiber dispersion (Example 5). Mixed dispersion B (Example 2), mixed dispersion C (Example 3), mixed dispersion D (Example 4) of cellulose fiber and glass fiber α with a content of 1% by weight,
Mixed dispersion liquid E (Example 5) was obtained, and water-containing inorganic compound-containing paper B (Example 2) and water-containing inorganic compound-containing paper C (
Example 3), paper d containing a hydrous inorganic compound (Example 4), and paper e containing a hydrous inorganic compound (Example 5) were obtained.

Regarding paper sheets containing hydrous inorganic compounds, c, d, e, yonetsubo,
The thickness, density, yield of hydrated inorganic compound, and flame retardancy were measured, and the results are shown in Table 1 and Figure 1.

Examples 6 to 8 In the case of Example 6, in Example 3, in the case of Example 7, in Example 4, and in the case of Example 8, in Example 5, a glass fiber with a diameter of 3 μm was used instead of glass fiber α. (hereinafter abbreviated as glass fiber β)
The total content of cellulose fiber and glass fiber β was 1% by weight in the same manner as in Example 3 for Example 6, Example 4 for Example 7, and Example 5 for Example 8.
A mixed dispersion F (Example 6), a mixed dispersion G (Example 7), and a mixed dispersion H (Example 8) of cellulose fiber and glass fiber β were obtained, respectively, and a water-containing inorganic compound-containing paper (implementation) was obtained. Example 6), paper g containing a hydrous inorganic compound (Example 7), and paper h containing a hydrous inorganic compound (Example 8) were obtained.

The basis weight, thickness, density, yield of hydrated inorganic compound, and flame retardance of papers f, g, and h containing hydrated inorganic compounds were measured, and the results are shown in Table 1 and FIG. 1.

Example 9 5 g of glass fibers with a diameter of 1 μm (hereinafter abbreviated as glass fiber γ) were added to 725 g of cellulose fiber dispersion ■, and 770 g of water was further added, and the mixture was stirred and mixed in a difficult-to-dissolve machine to dissolve cellulose fibers and glass fiber γ. A mixed dispersion of cellulose fiber and glass fiber γ having a total content of 1% by weight was obtained.

Mixed dispersion I 125g and aluminum hydroxide powder 8
G? The mixture was added, sufficiently dispersed and mixed using a stirrer, and hand-sheeted using a Juken-type test paper machine to obtain paper i containing water-containing inorganic compounds.

Regarding hydrated inorganic compound-containing paper 1, tsubo, thickness, density,
The yield and flame retardance of the hydrated inorganic compound were measured, and the results are shown in Table 1.

Examples 10 to 11 In Example 9, instead of glass fiber γ, Example 10
In the case of Example 11, the glass fiber α was used, and in the case of Example 11, the diameter was 0.
A mixed dispersion J (Example 10) of cellulose fibers and glass fiber α with a total content of cellulose fibers and glass fibers of 1% by weight was prepared in the same manner as in Example 9 except when using 32 μm glass fibers, respectively. In the case of Example 11, a mixed dispersion K of cellulose fibers and glass fibers with a diameter of 0.32 μm (hereinafter abbreviated as glass fiber δ) was obtained, and paper j containing a hydrous inorganic compound (Example 10) and a hydrous inorganic compound were obtained. The grammage, thickness, density, yield of the hydrated inorganic compound, and flame retardancy were measured for the hydrated inorganic compound-containing papers j and k obtained from the compound-containing paper k (Example 11), respectively, and the results were It is shown in Table 1.

Comparative Example 1 In Example 1, diameters of 0, . A cellulose fiber dispersion liquid having a cellulose fiber content of 1% by weight was obtained in the same manner as in Example 1 except that the 65 μm glass fiber was not added, and a water-containing inorganic compound-containing paper 1 was obtained.

Regarding hydrated inorganic compound-containing paper 1, tsubo, thickness, density,
The yield and flame retardance of the hydrated inorganic compound were measured, and the results are shown in Table 1 and Figure 1.

Comparative Examples 2 to 6 Comparative Example 2 in Example 1, Comparative Example 3 in Example 2, Comparative Example 4 in Example 3, Comparative Example 5 in Example 4, Example 6 is the same as Example 5, except that a glass fiber with a diameter of 5 μm (hereinafter abbreviated as glass fiber ε) is used instead of the glass fiber α, and Comparative Example 2 is the same as Example 1, and the comparative example is Cellulose fibers and glass Mixed dispersion M (comparative example 2), mixed dispersion N (comparative example 3), mixed dispersion O (comparative example 4), mixed dispersion of cellulose fiber and glass fiber ε with a total fiber ε content of 1% by weight Liquid P (
Comparative Example 5) and mixed dispersion Q (Comparative Example 6) were obtained, and paper m containing a hydrous inorganic compound (Comparative Example 2), paper n containing a hydrous inorganic compound (Comparative Example 3), paper containing a hydrous inorganic compound 0 ( Comparative Example 4), paper p containing a hydrous inorganic compound (Comparative Example 5), and paper q containing a hydrous inorganic compound (Comparative Example 6) were obtained.

The tsubo, thickness, density, yield of hydrated inorganic compounds, and flame retardance of papers m, n, as P, and q containing hydrated inorganic compounds were measured, and the results are shown in Table 1 and Figure 1. Ta.

Comparative Example 7 A cellulose fiber dispersion R with a cellulose fiber content of 1% by weight was obtained in the same manner as in Example 9, except that glass fiber γ was not added, and a paper r containing a hydrous inorganic compound was obtained. Ta.

Regarding paper r containing hydrous inorganic compounds, tsubo, thickness, density,
The yield and flame retardance of the hydrated inorganic compound were measured, and the results are shown in Table 1.

Example 12 5 g of aluminum hydroxide powder was added to 300 g of mixed dispersion 1 of cellulose fiber and glass fiber γ obtained in Example 9, thoroughly dispersed and mixed using a stirrer, and processed using a Juken test paper machine. A paper layer containing a hydrous inorganic compound was obtained by hand-making. The same operation was carried out two more times, and the resulting three paper layers containing the hydrated inorganic compound were superimposed in a wet state, and then compressed and dried in a conventional manner to obtain the hydrated inorganic compound-containing board S. Ta. Regarding the hydrated inorganic compound-containing board S, the basis weight, thickness, density, yield of hydrated inorganic compound, and flame retardance were measured, and the results are shown in Table 2.

Example 13 Aluminum hydroxide powder 4 to 400 g of mixed dispersion I
．． A water-containing inorganic compound-containing board t was obtained in the same manner as in Example 12 except that 5 g was added.

Regarding the hydrated inorganic compound-containing board t, the basis weight, thickness, density, yield of hydrated inorganic compound, and flame retardance were measured, and the results are shown in Table 2.

Example 14 45 g of aluminum hydroxide powder was added to 3000 g of the mixed dispersion I obtained in Example 9, thoroughly dispersed and mixed using a stirrer, and hand-made using a standard square test paper machine. An inorganic compound-containing board U was obtained.

Regarding the hydrated inorganic compound-containing board U, the basis weight, thickness, density, yield of hydrated inorganic compound, and flame retardance were measured, and the results are shown in Table 2.

Comparative Examples 8 to 9 Comparative Example 8 except that cellulose fiber dispersion R was used instead of the mixed dispersion in Example 12 for Comparative Example 8 and Example 14 for Comparative Example 9, respectively. In the case of Example 12 and Comparative Example 9, a board V containing a hydrated inorganic compound (Comparative Example 8) and a board W containing a hydrated inorganic compound (Comparative Example 9) were obtained in the same manner as in Example 14.

Example 15 The basis weight, thickness, density, yield of the hydrated inorganic compound, and flame retardancy of the hydrated inorganic compound-containing boards v and w were measured, and the results are shown in Table 2. 1 g of aluminum hydroxide powder was added to 200 g of mixed dispersion A of cellulose fibers and glass fibers α, thoroughly dispersed and mixed with a stirrer, and then water was added and the mixture was heated for 1000 m
+1, and the freeness of a cellulose fiber dispersion slurry containing glass fibers with a diameter of 4 μm or less and a predetermined amount of a hydrous inorganic compound was measured, and the results are shown in Table 3 and FIG.

Similarly, 2 g of aluminum hydroxide powder was added to 100 g of mixed dispersion A, and after sufficiently dispersing and mixing with a stirrer,
Water was added to bring the slurry to 10,100 O, and the freeness of a cellulose fiber dispersion slurry containing glass fibers with a diameter of 4 μm or less and a predetermined amount of a water-containing inorganic compound was measured, and the results are shown in Table 3 and FIG.

Furthermore, 2.75 g of aluminum hydroxide powder was added to 25 g of mixed dispersion A, and after sufficiently dispersing and mixing with a stirrer, water was added to bring the temperature to 10,100 O, and a predetermined amount of glass fibers with a diameter of 4 μm or less and a water-containing inorganic compound were added. Examples 16 to 25 The freeness of the cellulose fiber dispersion slurry containing the following was measured and the results are shown in Table 3 and Figure 2.In Example 15, mixed dispersion B was used instead of mixed dispersion A. (Example 16), mixed dispersion C (Example 17),
Mixed dispersion D (Example 18), mixed dispersion E (Example 19), mixed dispersion F (Example 20), mixed dispersion G (Example 21), mixed dispersion H (Example 20), Example 22),
Glass fibers with a diameter of 4 μm or less were prepared in the same manner as in Example 15 except that mixed dispersion I (Example 23), mixed dispersion J (Example 24), and mixed dispersion K (Example 25) were used. The freeness of a cellulose fiber dispersion slurry containing a predetermined amount of a water-containing inorganic compound and a water-containing inorganic compound was measured, and the results are shown in Table 3, FIG. 2, and FIG. 3, respectively.

Comparative Example 10 Water was added to 300 g of the cellulose fiber dispersion L obtained in Comparative Example 1 to make it 10,100 O, and the freeness of the cellulose fiber dispersion slurry was measured. The results are shown in Table 3, Figures 3 and 4.
Each is shown in the figure.

Comparative Examples 11 to 25 In Comparative Example 10, mixed dispersion A (Comparative Example 11), mixed dispersion B (Comparative Example 12), and mixed dispersion C (Comparative Example 13) were used instead of the cellulose fiber dispersion. , mixed dispersion D (comparative example 14), mixed dispersion E (comparative example 15),
Mixed dispersion F (Comparative example 16), mixed dispersion G (Comparative example 17), mixed dispersion H (Comparative example 18), mixed dispersion I (Comparative example 19), mixed dispersion J (Comparative example) Example 20),
Mixed dispersion K (Comparative example 21), mixed dispersion 0 (Comparative example 22), mixed dispersion P (Comparative example 23), mixed dispersion Q (Comparative example 24), cellulose fiber dispersion R ( A cellulose fiber-dispersed slurry containing glass fibers and a cellulose fiber-dispersed slurry were obtained in the same manner as in Comparative Example 10, except that Comparative Example 25) was used, and the freeness of the cellulose fiber-dispersed slurry was measured. The results are shown in Table 3, Figure 2, Figure 3 and Figure 4, respectively.

Comparative Examples 26 to 3° In Example 15, instead of mixed dispersion A, cellulose fiber dispersion L (Comparative Example 26), mixed dispersion 0 (Comparative Example 27), and mixed dispersion P (Comparative Example 28) were used. Filtered cellulose fiber dispersion slurry containing a hydrous inorganic compound was prepared in the same manner as in Example 15 except that mixed dispersion Q (Comparative Example 29) and cellulose fiber dispersion R (Comparative Example 30) were used. The freeness of cellulose fiber dispersion slurry containing glass fibers and hydrated inorganic compounds was measured, and the results are shown in Table 3, Figure 2, Figure 3 and Figure 4.
Each is shown in the figure.

Comparative Example 31 15 g of glass fiber α was added to 1485 g of water and disintegrated in a disintegrator to obtain a glass fiber dispersion S having a glass fiber content of 1% by weight.

The freeness of the glass fiber dispersion slurry was measured by adding water to 3,300 g of the glass fiber dispersion and bringing the temperature to 10,100 O. The results are shown in Table 3 and FIG. 2, respectively.

Similarly, 1 g of aluminum hydroxide powder was added to 5200 g of the glass fiber dispersion, and the mixture was thoroughly dispersed and mixed using a stirrer, and then water was added to make 1000 l, and the glass fiber dispersion slurry containing the hydrous inorganic compound was filtered. The results are shown in Table 3 and Figure 2.

Similarly, 2 g of aluminum hydroxide powder was added to 100 g of glass fiber dispersion 8, sufficiently dispersed and mixed with a stirrer, and then water was added to make 1000 g, resulting in a glass fiber dispersion slurry containing a hydrous inorganic compound. The freeness was measured and the results are shown in Table 3 and Figure 2.

Furthermore, 2.75 g of aluminum hydroxide powder was added to 825 g of the glass fiber dispersion, and after sufficiently dispersing and mixing with a stirrer, water was added to make the glass fiber dispersion slurry of 1000 l. The freeness was measured and the results are shown in Table 3 and Figure 2.

Comparative Examples 32 to 35 In Comparative Example 31, instead of glass fiber α, glass fiber β (Comparative Example 32), glass fiber ε (Comparative Example 33), glass fiber γ (Comparative Example 34), glass fiber δ Glass fiber dispersion T (Comparative example 32), glass fiber dispersion U (Comparative example 33), glass fiber dispersion V (Comparative example 34) and glass fiber dispersion W (Comparative Example 35) were obtained, respectively.

Further, in Comparative Example 31, instead of glass fiber dispersion S, glass fiber dispersion T (comparative example 32), glass fiber dispersion U (comparative example 33), and glass fiber dispersion V (comparative example 34) were used. The freeness of the glass fiber dispersion slurry and the freeness of the glass fiber dispersion slurry containing a hydrous inorganic compound were determined in the same manner as in Comparative Example 31 except that , glass fiber dispersion W (Comparative Example 35) was used, respectively. measure,
The results are shown in Table 3, Figure 3, and Figure 4, respectively.

As is clear from the margin Tables 1 and 2 and Figure 1 below, the diameter is 4
By using a cellulose fiber dispersion slurry containing hydrous inorganic compounds containing a predetermined amount of glass fibers of µm or less in size and making paper using a normal papermaking method, the retention of hydrous inorganic compounds in the paper or board can be dramatically increased. In particular, even if the content of the glass fiber is very small, a very remarkable effect of improving the retention of water-containing inorganic compounds can be obtained, and as a result, it is possible to obtain a flame retardant that has the desired flame retardancy very easily and economically. It can be seen that burnable paper and flame retardant board can be produced.

Furthermore, as is clear from Table 3, FIG. 2, FIG. 3, and FIG. It can be seen that the water retention performance is dramatically improved, and even if the content of the glass fibers is extremely small, an extremely significant improvement in water retention performance can be obtained.

[Effects of the Invention] As detailed above, the present invention involves preparing a cellulose fiber dispersion slurry containing glass fibers with a diameter of 4 μm or less and a predetermined amount of a hydrous inorganic compound, and making paper using a normal papermaking method. As a result, the water retention performance of slurry containing a large amount of hydrated inorganic compounds such as aluminum hydroxide can be improved, and paper made of hydrated inorganic compounds such as aluminum hydroxide can be improved without using organic retention aids that have a negative effect on flame retardancy. Alternatively, the yield into the board can be dramatically increased. Moreover, flame-retardant paper or flame-retardant board having desired flame retardancy can be produced very easily and economically.

[Brief explanation of drawings]

Figure 1 shows the relationship between the yield of hydrous inorganic compounds and the content of glass fiber in the total weight of cellulose fibers and glass fibers in the slurry, and Figures 2 to 4 show the freeness of the slurry and the cellulose in the slurry. This is a diagram showing the relationship between the content of glass fiber in the total weight of fibers and glass fibers. Figure 2 shows the case where glass fiber α is used, Figure 3 shows the case where glass fiber β is used, and Figure 4 shows the case where glass fiber β is used. shows the case where glass fiber C was used.

Claims (3)

[Claims] (1) Prepare a slurry containing 5-60% by weight of cellulose fibers, 15-94% by weight of hydrated inorganic compounds, and 0.05-80% by weight of glass fibers with a diameter of 4 μm or less. 1. A method for producing flame-retardant paper or board, which comprises forming a flame-retardant paper or a flame-retardant board. (2) The flame-retardant paper according to claim 1, wherein the hydrated inorganic compound is at least one selected from aluminum hydroxide, magnesium hydroxide, calcium hydroxide, gypsum dihydrate, and calcium aluminoxide. Or how to make flame retardant boards. (3) A method for producing flame-retardant paper or a flame-retardant board according to claim 1 or 2, wherein the paper is formed by overlapping two or more paper layers.