JPS61101438A - Manufacture of gypsum paper - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Technology] The present invention relates to a method for producing gypsum paper, and more specifically, uses dihydrate and/or insoluble anhydrite as the gypsum, gypsum and inorganic fibrous material as the fiber material. A slurry obtained by combining a small amount of a fixing agent and mixing with water is prepared by a conventional method.

[Conventional technology]

In recent years, there has been a demand for non-combustible paper using non-polluting materials, and in response to this demand, non-combustible paper containing aluminum hydroxide as the main non-combustible component has been developed.

However, this non-combustible paper is expensive due to the aluminum hydroxide, so there is a demand for a more economical non-combustible paper.

In view of the above circumstances, a method for producing noncombustible paper using gypsum as a noncombustible component was proposed (Japanese Unexamined Patent Publication No. 58729/1983,
-400). In all of these prior arts, the crude raw material dihydrate gypsum is calcined to form calcined stone if (α-type or β-type hemihydrate), and this is used as the raw material, and the calcined gypsum reacts with water. However, the method for producing noncombustible paper using calcined gypsum as a noncombustible component has the following problems. It requires equipment and energy for firing calcined gypsum to produce calcined gypsum. ■Calcined gypsum dissolves in IC within a short time in water and crystallizes dihydrate, so papermaking slug containing calcined gypsum cannot be used. I) The yield of - is poor, and at the same time causes troubles such as clogging and scaling of f cloth.
4.Easy to be destroyed when transferred to felt due to force and■
The strength of the product is weaker than conventional non-combustible paper.

For the above reasons, it is currently difficult to use gypsum hemihydrate as a nonflammable raw material.

[Purpose of the invention]

In view of the above-mentioned circumstances of the known production technology for noncombustible paper using gypsum as a noncombustible raw material, the present inventors have developed a method using gypsum instead of calcined gypsum.
We conducted research to find a method for manufacturing noncombustible paper that uses gypsum dihydrate, which is a raw material, and can produce a product that is equivalent to or better than conventional noncombustible paper using aluminum hydroxide. As a result, we created a composition in which 9 Lude and an inorganic fibrous substance were combined as fiber components to be combined with dihydrate gypsum, and two specific types of polymeric substances were combined in specific ratios as fixatives. The present invention was completed based on the knowledge that by mixing to form a slurry, a noncombustible paper with quality equal to or higher than products using aluminum hydroxide can be obtained without the drawbacks associated with the method using calcined gypsum described above.

As is clear from the above description, an object of the present invention is to provide a method for producing gypsum paper having a quality equal to or higher than that of aluminum hydroxide noncombustible paper. The key point is to make paper from a slurry made by mixing gypsum dihydrate (and or insoluble anhydrite), inorganic fibrous material, and a specific fixative in water in a specific ratio.

[Structure of the invention]

The present invention provides dihydrate and/or insoluble anhydrite 50~
96 parts by weight, 2 to 20 parts by weight of Group, 2 to 30 parts by weight of an inorganic Xa fibrous material, and 0.5 to 5 parts by weight of a fixing agent are mixed with water to form a slurry, and from the slurry a solid is prepared by a conventional method. A method for producing gypsum paper characterized by paper-cutting! ◎ In the method of the present invention, dihydrate gypsum and/or insoluble anhydrite are used as gypsum raw materials. Therefore, unlike the prior art using calcined gypsum, there is no need to adjust the hardening speed before and after papermaking.

These dihydrate gypsum and/or insoluble anhydrite (hereinafter both may be collectively referred to as "insoluble gypsum used in the present invention") are used in the chemical industry, for example, by-product gypsum from the hydrofluoric acid or phosphoric acid manufacturing process, Either flue gas desulfurization gypsum or other by-product gypsum or natural gypsum can be used.

The amount of insoluble gypsum used in the present invention is 1 part of the composition excluding water and fixing agent] iJ (hereinafter simply referred to as "part").
50 to 96 parts by weight, preferably 65 to 8 parts by weight
There are 5 parts. If the blending amount is less than 50 parts, it is difficult to obtain the desired flammability (for example, passing grade 1 disaster prevention) for the obtained gypsum paper, and on the other hand, if it exceeds 96 parts, the papermaking efficiency decreases and Various characteristics of

Furthermore, the range of fineness of the insoluble gypsum used in the present invention is as follows:
Preferably 1,000 to 6,00 in Blaine method specific surface area
It is 0 cm2/li. . The fineness is 1,000cm2
If it is coarser (smaller) than 6./9, the insoluble gypsum will not easily settle out of the slurry according to the present invention, which will be described later.
If the insoluble gypsum is finer (larger) than 000aR279, the insoluble gypsum will not form a paper product and will be easily transferred during filtration.9 Both cases are unfavorable.

The material used in the present invention is not limited to any particular material, and any water-dispersible cellulose fibrous material such as coniferous wood, hardwood, or waste paper may be used without any problem. Among them, softwood-based bleached/gulp (NBKP) is preferred, and the higher the proportion of NBKP used, the better quality gypsum paper can be obtained. The blending amount of the pulp is 2 to 20 parts, preferably 5 to 15 parts, based on 100 parts of the above-mentioned composition. If the amount is less than 2 parts, the properties of paper cannot be maintained, and if it exceeds 20 parts, the non-flammable paper which is the object of the present invention cannot be obtained.

In addition, the range of the freeness of the mother pulp used in the present invention is 40088 or less, preferably 20
It is 0 to 100cc.

The inorganic fibrous material used in the present invention refers to a fibrous or acicular inorganic material. Specific examples thereof include glass fibers, rock wool, and acicular calcium silicates (such as walrus night, topelmolite, and xonotrite). These fibrous substances are used in a mixture of two or more types spread over 1s''.

The amount of the inorganic fibrous material used in the present invention is 2 to 30 parts, preferably 7 to 2 parts, per 100 parts of the above-mentioned composition.
It is 0 copies. If the amount used is less than 2 parts, the strength of the paper-forming material according to the present invention when wet is insufficient, making it difficult to perform stable paper making. There is no improvement in the effect of this method, which is uneconomical. When the blending amount is within the above range, there will be no problems such as the paper-forming material peeling off or cutting during the transition from wire to felt, and it will be stable. It becomes possible to carry out the papermaking process. Finally, a product (gypsum paper) with excellent strength can be produced economically.

The fixing agent used in the present invention is a combination of a water-soluble anionic organic polymeric substance and a cationic organic polymeric substance in a fixed ratio.

As the anionic substance, a partially hydrolyzed acrylamide polymer or a copolymer of acrylamide and an unsaturated basic acid copolymerizable with acrylamide are particularly effective.

However, the following substances, namely, acrylic acid alone or a copolymer, anionically modified starch such as oxidized starch, and other anionic sizing agents can also be used in combination with the above-mentioned partial hydrolyzate of acrylamide polymer, etc.

On the other hand, cation-modified polyacrylamide resins are particularly effective as the cationic substances, and Annitz reaction products, Hofmann decomposition products of the resins, or combinations of acrylamide and quaternary amine-containing unsaturated polymers are particularly effective. Any of the polymers can be used alone or in combination of two or more.

In the method of the present invention, a fixed proportion of the fixing agent, that is, the water-soluble anionic organic polymer substance described above, is added to the composition consisting of the insoluble gypsum, matrix, and inorganic fibrous material used in the present invention. The desired effect (note: eliminating the shortcomings of known methods) can be obtained by combining cationic organic polymeric substances and cationic organic polymer substances.

The proportion of the fixing agent used is 0.5 to 5 parts, preferably 1.5 to 3 parts in terms of solid content, per 100 parts of the composition. The mixing ratio of the anionic substance and the cationic substance in the fixing agent is preferably in the range of 0.5 to 1.5 of the former to 1 of the latter in terms of solid content weight ratio.

The effect of the fixing agent in the method of the present invention is to improve the papermaking yield and to improve the strength and water resistance of the obtained gypsum paper. Incidentally, when looking at the retention rate, it is only 30 to 40% when no fixing agent is used, and it is only 30 to 40% when no fixing agent is used. Even if one of the on-types is used alone, the rate remains at 50-60%, whereas when an anion-type and a cation-type are used together, the increase dramatically increases to 80-90%. The reason for the effects of such a combination of fixatives is not clear, but if different ions are used in appropriate combinations according to the potential of the material to be treated, the crosslinking action of the fixative will form a glue on the gypsum particles. is,
It is thought that as a result of the entanglement between the floc and the inorganic fibrous material becoming stronger, the excellent effects of improving the yield O and improving the strength of the product gypsum paper as described above are achieved. If the proportion of such a fixing agent used is less than 0.5%, the effect will be insufficient, and if it exceeds 5%, the effect will not be improved and it will be uneconomical.

In the method of the present invention, in addition to the above compounded materials, in order to improve the physical properties of the product (gypsum paper), a paper strength enhancer, a flame retardant treatment agent, a coloring agent, or a gloss or lubricity imparting agent is used. Fillers etc. can be added. The proportion of these formulations for use is within the range that allows them to replace a portion of the insoluble gypsum used in the present invention.

In the method of the present invention, the above raw materials are mixed with water to form a slurry, and the solid content is extracted from the slurry by a conventional method.

The method of mixing the various raw materials and water is not limited, and a predetermined amount of each raw material may be sequentially added to water and uniformly dispersed under stirring, or a mixture obtained by adding a small amount of water to the raw material composition and kneading it. may be added to a large amount of water and uniformly dispersed to form a slurry.

The ratio of the raw material composition to water, that is, the slurry concentration, is not limited and can be selected from within the concentration range of solids in conventional papermaking methods. Determined according to physical properties and other factors.

The method for extracting the solid content from the slurry according to the present invention obtained as described above is not limited, and any conventional paper making method (for example, cylinder method, Fourdrinier method) can be used without any problem. Available.

〔Effect of the invention〕

The gypsum paper obtained by the method of the present invention manufactured as described above exhibits various physical properties depending on the manufacturing conditions. As an example, the basis weight is 120. j7/m2, JISP-811
3 tensile strength MD) 4kli1 or more, JISA
Passed disaster prevention level 1 in flame retardancy test by -1322.
This performance is equivalent to that of commercially available non-combustible paper. According to the method of the present invention, dihydrate gypsum or insoluble Noncombustible paper using anhydrite as the main raw material can be easily produced by papermaking using conventional methods.

The thus obtained gypsum paper according to the present invention can be used, for example, as wallpaper,
It can be widely applied to make interior building materials nonflammable, such as fusuma paper, vinyl cloth or lining paper for vinyl flooring, and ceiling surface materials.

In addition, it can be applied to a wide range of applications such as surface materials for air conditioning ducts, heat-insulating filters, fireproof coatings, and securities paper.

〔Example〕

Experimental Example L Paper was made under the same conditions from a slurry in which 10 parts of gelatin and 90 parts of various types of gypsum were dispersed in water, and the yield of raw materials was measured. In addition, to the same combination of raw materials, an anionic acrylamide fixer (product name: Filex M, manufactured by Closing Chemical Industry Co., Ltd.) was added to the outside at 1% by weight (hereinafter qb) in terms of solid content, and then Cationic acrylic acid fixer (Phyrex RC-107 manufactured by the same company) 0.6%
Paper was made from the slurry to which was added, and the yield of 9 was measured. When using gypsum hemihydrate, 0.4% sodium citrate was added to the gypsum. However, in the papermaking process, regardless of the composition, the material being made may peel off or break during the transition from wire to felt, probably because the wet strength of the material being made is weak.
Problems such as storage occurred.

The relationship between the type of gypsum (and the presence or absence of a fixative) and the yield in the above is shown in Table 1 below. According to the same table, when using dihydrate gypsum or ■-type anhydrite, the improvement in yield value is remarkable by adding a fixing agent, but when using α-type or β-type anhydrite,
When molded hand plaster is used, the improvement in yield value is insufficient.

Experimental Example 2 A predetermined amount of softwood (LBKP)/hardwood (NBKP) 872 pulp (Canadian standard freeness 350CC) was sufficiently dispersed in 4001114°C water, followed by ℃ flue gas desulfurization gypsum (dried). Condition, fineness plain value 18
A predetermined amount of 00 cm''/I) was added and mixed by stirring.

0.2Ii of an anionic fixing agent (manufactured by Meiho Kagaku Kogyo ■, trade name: Filex M) was added to the mixture, and then a cationic fixing agent (manufactured by Meiho Kagaku Kogyo, trade name: Filex Re2O3) was added and mixed.
After adding and mixing 0.12#, add water to bring the total amount to 10t.
It was made into a diluted slurry. Using these slurries, paper was made by a conventional method to obtain a paper of 20×25 crn.

Paper with an IPIk of 2001/m" was obtained. The yield of these products (each with varying proportions of 4 rugs and gypsum) was measured, and the flame retardant (JIS A1322
) was tested. For comparison, the same measurements and tests were conducted on a sample that was carried out in the same manner except that no fixing agent was added (RUN a). Table 2 shows the blending ratios of raw materials and the results. As is clear from the same table, if the usage rate of gypsum dihydrate is 80% by weight or less (qb) or more, the flame retardance is passed.
A yield of 76% or more can be obtained when the usage rate of /4 Lug is 5 inches or more, but when no fixer is used, a yield of only 48% (9) can be obtained even when the usage rate of /4 Lug is 10 inches.

Table 2 Experimental Example 3゜In addition to each raw material used in Experimental Example 2, the same procedure as Experimental Example 2 was carried out except that a predetermined amount of glass fiber and/or inorganic material listed in Table 3 below was added. . Also,
In one example, paper was made using hydrofluoric acid by-product insoluble anhydrite (fineness: 2150 cm''/Ii) in place of dihydrate gypsum (R[11).

Table 3 shows the blending ratio of the raw materials and the results (however, the degree of adhesion to paper machine wire was tested instead of the flame retardancy test). The details of the glass fiber and inorganic material and the criteria for adhesion to the wire are as follows.

Wallas Night Natural product from America, length 100~S
Needle-shaped crystalline rock of OOμ Cotton Slag wool with a diameter of 5μ Calcium carbonate Limestone crushed product, average particle size Axis
- Particle size 2-5μ aluminum hydroxide
Reagent grade 1 plus fiber E glass, 6 cut lengths Adhesion criteria for wire: ◎ Very good (no adhesion at all) ○ Good (almost no adhesion) Δ Slightly poor (some adhesion) × Poor (Significant adhesion) As shown in Table 3, when the specified amount of glass fiber and/or inorganic fibrous material is not blended (RUNAI) or when an inorganic powder material is used instead of the inorganic fibrous material. (RIJN Muro, 7.8) has poor or slightly poor adhesion to wire in papermaking conditions. However, when a predetermined amount of the glass fiber and/or inorganic fibrous material according to the present invention is used, the adhesion to the wire is very good or good, and the yield is as good as 79 cm or more. .

Claims (3)

[Claims] (1) Dihydrate and or insoluble anhydrite 50-96
Parts by weight, 2 to 20 parts by weight of pulp, 2 to 20 parts by weight of inorganic fibrous material
A method for producing gypsum paper, which comprises mixing 30 parts by weight and 0.5 to 5 parts by weight of a fixing agent with water to form a slurry, and removing solid content from the slurry by a conventional method. (2) As a fixing agent, a water-soluble anionic organic polymeric substance and a water-soluble cationic organic polymeric substance are used in a weight ratio of 1 to 1;
The manufacturing method according to claim (1), wherein the latter is used in combination of 0.5 to 1.5. (3) Claim No. 1 (2) in which glass fiber, rock wool, or acicular calcium silicate is used as the inorganic fibrous material.
The manufacturing method described in item 1).