JPH0835196A - Mica paper and its manufacturing method - Google Patents

Abstract

(57) [Summary] [Structure] The mica paper of the present invention is a paper produced by aggregating synthetic swellable fluoromica particles with an inorganic aggregating agent and fixing them on a fiber. It is manufactured by adding an inorganic coagulant to a slurry consisting of (1) to agglomerate the synthetic swellable fluoromica particles to fix the fibers on the fiber, and paper-making the same. [Effect] Since the mica paper of the present invention is manufactured by the papermaking method, it is inexpensive and can be mass-produced. The obtained mica paper can be used for writing characters and pictures like general paper, and is expected to be used as non-combustible or flame-retardant shoji paper, wallpaper or other non-combustible or flame-retardant paper.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to mica paper and a method for producing the same, and more particularly to mica paper which is non-combustible or flame-retardant and has excellent mechanical strength and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, many mica sheets and mica papers containing natural mica have been reported. However, natural mica is a non-swelling mica, and the natural mica itself does not have sheet forming ability (adhesive strength) and contains impurities, so the amount of fibers such as pulp and organic binder such as polyamide is small. I could only make paper with low mechanical strength. Therefore, only mica sheets and mica papers containing natural mica and those having low heat resistance were obtained.

On the other hand, since synthetic swellable fluoromica has a sheet-forming ability, a method in which a swellable fluoromica sol is flowed down and dried on a releasable plate without an organic binder (hereinafter A sheet or paper can be formed by using a coater method (Japanese Patent Laid-Open No. 26251/1991).
4 publication). However, in the papermaking method which is inexpensive in manufacturing cost and can be mass-produced, since the particle diameter of the synthetic swelling fluoromica is small, the swelling fluoromica particles come out during the papermaking, which makes the papermaking difficult.

Japanese Patent Publication No. 52-18399 discloses a mixed paper made of synthetic montmorillonite, and Japanese Patent Publication No. 54-15.
Japanese Patent No. 043 discloses an inorganic film in which an inorganic fiber is added to a synthetic montmorillonite sol. However, these specific manufacturing methods are those manufactured by a coater method using a synthetic montmorillonite sol as a raw material, and are not manufactured by paper-making like ordinary paper.

Further, Japanese Patent Application Laid-Open No. 61-89400 describes a papermaking paper having a mica content of 40 to 96% by weight. However, this is a paper made by adding a large amount of an organic binder such as starch powder or emulsion to a mixed slurry of natural mica and kraft pulp.

[0006]

The object of the present invention is to produce letters by means of a papermaking method which is inexpensive and can be mass-produced, has smoothness, is uniform, and has no unevenness on the surface. It is intended to provide a non-combustible or flame-retardant mica paper having high mechanical strength.

[0007]

Means for Solving the Problems The present inventors have added an inorganic coagulant to a slurry in which synthetic swellable fluoromica particles and fibers are dispersed, whereby fine synthetic fluoromica particles are aggregated into fibers. The present invention has been made by finding that fixing and papermaking are possible.

That is, the mica paper of the present invention is a paper made of synthetic swellable fluoromica particles which are agglomerated by an inorganic coagulant and fixed on fibers, and is made into a slurry comprising synthetic swellable fluoromica particles and fibers. It is produced by adding an inorganic coagulant, aggregating the synthetic fluoromica particles to fix the fibers on the fiber, and paper-making this.

The present invention will be described in detail below.

The synthetic swellable fluoromica used in the present invention is
An artificially synthesized mica, which is produced by a melting method or an intercalating method, is used. The preferred synthetic swelling fluoromica is the synthetic swelling fluoromica or synthetic fluoromica ion exchange material described below.

The preferred synthetic swellable fluoromica is sodium tetrasilicon fluoromica [NaMg _2.5 Si ₄ O ₁₀ F
₂ ], Lithium tetrasilicon Fluorine mica [LiMg _2.5 Si
₄ O ₁₀ F ₂ ], lithium teniolite [LiMg ₂ Li
Si ₄ O ₁₀ F ₂ ], and the like.

Particularly preferred synthetic swellable fluoromica used in the present invention is sodium silicofluoride or lithium silicofluoride (Na ₂ SiF ₆ , L ₂₎ prepared by the intercalating method described in JP-A-2-149415.
i ₂ SiF ₆ ) and a mixture of talc; or a mixture of sodium silicofluoride or lithium silicofluoride, sodium fluoride or lithium fluoride (NaF, LiF), and talc by heat treatment at 700 to 1000 ° C. The following formula (I): α′LF · γ (aMgF ₂ · bMgO) · δSiO ₂ (I) (wherein L is an interlayer ion and represents a Na ion or a Li ion, and α ′ is 0.1 to 2). , Γ represents 2 to 3.5, δ represents 3 to 4, a and b each represent 0 to 1, and a + b = 1.).
Specific examples thereof include synthetic swelling mica: Somascif (trade name, manufactured by Coop Chemical Co., Ltd.).

The intercalation method is a manufacturing method in which Na ions or Li ions are coordinated between the layers of talc, and at the same time, the hydroxyl groups are replaced with fluorine. The synthetic swelling fluoromica produced by this production method is superior in swellability as compared with the molten synthetic swelling mica obtained by the conventional melting method,
In water, the thickness is 0.1 μm or less, and the size in the plane direction is 1
Disperses in the form of flaky fine particles with sides of several μm to several tens of μm.

The interlayer ions of the synthetic swelling fluoromica have a high ratio of exchangeable cations among exchangeable cations and non-exchangeable cations, and show a high ion exchange capacity of 50 to 110 meq / 100 g. This product swells in water and is easily cleaved, and interlayer ions can be easily ion-exchanged with other cations.

The synthetic fluoromica ion exchange material used in the present invention is one of the interlayer ions of synthetic swelling fluoromica.
The exchangeable ions are ion-exchanged with other inorganic cations, and the synthetic fluoromica ion-exchanged product also has a characteristic that the particle shape before the ion exchange is substantially maintained and extremely thin flaky fine particles are formed.

A particularly preferred synthetic fluoromica ion exchange product is the following formula (II) obtained by ion-exchange of interlayer ions of the synthetic swelling fluoromica obtained by the intercalation method described above: αMF · βLF · γ (AMgF ₂ · bMgO) · δSiO ₂ (II) (In the formula, M is an interlayer ion and represents an inorganic cation, L is an interlayer ion and represents Na ion or Li ion, and α is 0.
01 to 1.99, β to 0.01 to 1.99, α + β to 0.1 to 2, γ to 2 to 3.5, δ to 3 to 4, and a And b each represent 0 to 1 and a + b = 1).

The ion exchange rate between the interlayer ions of the synthetic swelling fluoromica and other inorganic cations is preferably 95 equivalent% or less. If the exchange rate exceeds 95 equivalent%, the aggregates of the ion exchange products become too large, the swelling ability decreases sharply, the sheet forming ability decreases, and the strength of the paper tends to decrease. Those having an ion exchange rate of 90% or more have excellent electrical characteristics.

The inorganic coagulant used in the present invention is preferably an inorganic salt of aluminum, and specific examples thereof include aluminum sulfate. The amount of aluminum sulfate added is preferably an amount capable of forming flocs to the extent that mica particles do not flow out from the gap of the pulp, and is 0.1 to 20% by weight, preferably 2 to 20% as aluminum sulfate based on the solid content in the slurry.
About 15% by weight is good. If the flocs become too large, the smoothness of the surface of the obtained mica paper will be impaired and the mechanical strength will also decrease.

The fiber used in the present invention is preferably a natural pulp, and examples thereof include wood pulp, chaff fiber, seed fiber and tension fiber. In addition, it is preferable to use these fibers after beating them in advance.

The content of pulp fibers is 1 to 30% by weight, preferably 20% by weight or less. The amount of pulp fiber added is 3
When it exceeds 0% by weight, the organic content in the mica paper increases and it is not incombustible, which is not preferable. Therefore, the content of the synthetic swelling fluoromica is preferably 70 to 99%.

In order to further increase the mechanical strength of the mica paper of the present invention, a small amount of an organic binder such as ethylene glycol, polyvinyl alcohol, polyacrylic acid salt, polyacrylamide or polyethylene glycol may be used.

The raw material of the car paper of the present invention may be a natural or synthetic non-swelling clay mineral mixed with a synthetic swelling fluoromica or an ion exchange product thereof. The addition of the non-swelling clay mineral improves drainage of the slurry mixed with fibers and the like during the papermaking process and shortens the drying time, which is particularly useful when a large amount is produced using a continuous device. However, the non-swelling clay mineral itself does not have a sheet-forming ability, and if added in a large amount, the mechanical strength of the obtained mica paper decreases, so the addition amount of the non-swelling mica is 20% by weight or less. Is good. Examples of the non-swelling clay mineral include natural mica, synthetic non-swelling fluoromica, and other non-swelling clay minerals.

The method for producing the mica paper of the present invention will be described below, but the present invention is not limited to the following description.

Aluminum sulfate is added to a slurry in which pulp fibers beaten in advance and synthetic swelling fluoromica are mixed to form flocs. The slurry in which the flocs are formed is applied to a paper machine to make a paper, which is then pressed and dried to obtain mica paper. The concentration of the slurry is not particularly limited as long as it can be applied to a paper machine, but generally 0.1 to 20% by weight is preferable.

When a synthetic fluoromica ion exchange material is used as the synthetic fluoromica, it is necessary to ion-exchange the interlayer ion of the synthetic swelling fluoromica with another cation. The method of is mentioned.

As a method of ion-exchanging Na ions or Li ions of interlayer ions with other inorganic cations,
For example, a method in which a solution in which the concentration of the synthetic swelling fluoromica is adjusted to 0.1 to 10% by weight and an aqueous solution containing an inorganic cation are mixed and then stirred are performed. As the aqueous solution containing an inorganic cation, various salts such as carbonates, hydrochlorides, nitrates and sulfates dissolved in water can be used.

As a stirring method, a usual stirrer can be used, but among them, a high speed stirrer such as a mixer is used.
It is preferable because the ion exchange reaction time can be shortened. Further, the liquid temperature during stirring may be increased to promote the ion exchange reaction.

When the interlayer ions are ion-exchanged with two or more kinds of inorganic cations, they are simultaneously ion-exchanged with two or more kinds of cations, or they are ion-exchanged with a specific cation and then the cations of the cations are exchanged. You may exchange a part of ion with another cation again. In addition, when sufficient ion exchange cannot be performed by one-time ion exchange, it is possible to increase the ion exchange rate by repeating ion exchange. Since the synthetic fluoromica ion exchange product thus obtained contains an excess of salts, it is preferably washed with water.

As a method of washing the synthetic fluorine mica ion exchange product, for example, a water washing method such as a filtration method, a centrifuge method and a gradient method can be used. In addition, in order to increase the cleaning efficiency,
You may combine 2 or more types of these methods. Next, this washed product is dispersed in water to form a sol.
Using a known dispersing device such as an ultrasonic disperser or a homogenizer, it is uniformly dispersed to obtain a sol of synthetic fluorine mica ion exchange product.

The inorganic cation used in the synthetic fluoromica ion exchange material is not particularly limited as long as it is an inorganic cation that can be ion-exchanged with Na ion or Li ion which is an interlayer ion of the synthetic swelling fluoromica. For example,
Examples include cations such as potassium, barium, lead, tin, copper, iron, titanium and nickel.

[0031]

In the present invention, by adding aluminum sulfate, which is an inorganic coagulant, to the synthetic swelling fluoromica particles which are fine and thin, the mica particles have a minimum size that is entangled in the gaps between pulp fibers. Agglomerates, and it becomes possible to make mica paper. Further, in the present invention, since the synthetic swelling fluoromica particles excellent in sheet forming ability are used as the raw material, the addition amount of pulp fiber can be suppressed to a minimum, excellent mechanical strength, and ordinary paper The same writable mica paper can be obtained. Furthermore, the mica paper obtained by adding 70% by weight or more of the synthetic swellable fluoromica particles has an oxygen index of 90 or more and is nonflammable.

[0032]

The mica paper obtained according to the present invention is a non-combustible or flame-retardant paper, and has smoothness, and since it uses plant fibers such as pulp, it has excellent printability and printability. Characters and pictures can be written like ordinary paper. Further, since the mica paper of the present invention is manufactured by the papermaking method, it is inexpensive and can be mass-produced.

Particularly, the amount of the synthetic swelling fluoromica added is 70.
Mica paper of more than weight% is used as a non-combustible paper.
It can be used for various purposes such as official documents, non-combustible shoji paper, non-combustible wallpaper, etc.

[0034]

【Example】

Example 1 Synthetic swelling fluoromica (ME, manufactured by Corp Chemical)
Then, the NBKP pulp beaten product was dispersed in water to make 1,000 ml of a 5% slurry, and then 10% aluminum sulfate 5
0 ml was added and stirred with a high speed mixer to prepare a mixed slurry. The resulting mixed slurry was handmade (25 x 2
Paper was made with a 5 cm square and a wire mesh opening of 80 mesh. Then, it was squeezed and dried at 100 ° C. for 4 minutes to obtain noncombustible mica paper. Non-combustible mica papers A and B shown in Table 1 were obtained according to the mixing ratio of the synthetic swelling fluoromica and NBKP pulp.

[0035]

[Table 1]

Example 2 Incombustible mica papers C and D shown in Table 2 were obtained in the same manner as in Example 1 except that the synthetic swellable fluoromica was replaced by a synthetic fluoromica ion exchange product prepared by the following method. It was Synthetic swelling fluoromica (ME, made by Corp Chemical) 2
0.0 g was dispersed in pure water and left overnight to obtain 1,000 ml of a 2% synthetic swelling fluoromica dispersion. To this dispersion was added 75 ml of a 15% KCl aqueous solution, and the mixture was stirred at room temperature for 3 hours using a stirrer, so that most of the Na ⁺ intercalation ions were K ^+.
An ion exchange product substituted with was obtained. This ion exchange product was filtered, washed with 5,000 ml of distilled water to form a cake, which was dispersed in water to prepare a 10% sol. The obtained sol had a weak swelling property.

[0037]

[Table 2]

Example 3 Synthetic fluorine mica ion-exchange material prepared in Example 2, synthetic non-swelling mica (MK: made by Corp Chemical) and NB.
KP pulp beaten product is dispersed in water to prepare 5% slurry 1.
After making 000 ml, 50 ml of 10% aluminum sulfate and polyacrylamide (Kurita high holder 351)
0.05 g was added and stirred with a high speed mixer to prepare a mixed slurry. Then, in the same manner as in Example 1, an incombustible mica paper was obtained. Noncombustible mica papers E, F, and G shown in Table 3 were obtained according to the mixing ratio of the synthetic fluoromica ion exchange product, the synthetic non-swelling fluoromica, and the NBKP pulp.
The non-combustible mica paper G had good drainage during papermaking, and the drying time was shortened.

[0039]

[Table 3]

The physical properties of the non-combustible mica papers obtained in Examples 1 to 3 were measured by the following methods and shown in Table 4. (Measurement Method) Tensile Strength (kg / 15 mm) Based on the method defined in JIS-P8113, the tensile strength of a mica paper having a width of 15 mm was measured at room temperature using a tensile strength measuring device. Tear strength (g / 16 sheets) Based on the method defined in JIS-P8116, a tear strength measuring device was used to measure the tear strength when 16 sheets of mica paper were stacked.

Bursting strength (kg / cm ² ) Bursting strength was measured at room temperature using a bursting strength measuring device in accordance with the method specified in JIS-P8112. Elongation (%) Elongation was measured at room temperature using an elongation measuring device according to the method specified in JIS-P8132. Oxygen index The oxygen index was measured using an oxygen index measuring device in accordance with the method specified in JIS-K7201. Oxygen index 9
0 or more is made non-combustible.

[0042]

[Table 4]

Comparative Example 1 80% by weight of natural mica was used as the synthetic swellable fluoromica of Example 1.
Comparative mica paper was produced in the same manner as in Example 1 except that The natural mica did not entangle with the fibers, and the natural mica powder was separated, so that the comparative mica paper could not be made into paper.

Comparative Example 2 Using 80% by weight of the synthetic swellable fluoromica of Example 1,
A comparative mica paper was produced in the same manner as in Example 1 except that aluminum sulfate was not used. At the time of papermaking, mica particles flowed out from the wire mesh of the papermaking machine, and the obtained mica sheet became paper with a high pulp content, and it was not possible to produce a mica sheet with a high mica content.

As described above, since the mica itself does not have a sheet forming ability, the mica paper containing a large amount of the mica cannot be produced without using the organic binder. Also, it is understood that mica paper having a high content of mica cannot be obtained even when the synthetic swelling fluoromica having a sheet forming ability is used unless aluminum sulfate which is a coagulant is used.

Claims (6)

[Claims] 1. A mica paper produced by paper-making from synthetic swellable fluoromica particles which are agglomerated by an inorganic aggregating agent and fixed on fibers. 2. A synthetic swellable fluoromica obtained by heat-treating a mixture of talc and alkali silicofluoride and / or alkali fluoride, represented by the following formula (I): α′LF · γ (aMgF ₂ · bMgO) · δSiO ₂ (I) (wherein, L represents a Na ion or Li ions in the interlayer ion, [alpha] 'is 0.1 to 2, gamma represents 2 to 3.5, [delta] is a 3-4 And m is a synthetic swelling fluoromica represented by the formula, a and b each represent 0 to 1, and a + b = 1. 3. A synthetic swellable fluoromica obtained by ion-exchange of interlayer ions of a synthetic swellable fluoromica obtained by heat-treating a mixture of talc and alkali silicofluoride and / or alkali fluoride. (II): αMF · βLF · γ (aMgF ₂ · bMgO) · δSiO ₂ (II) (In the formula, M represents an interlayer ion and an inorganic cation, L represents an interlayer ion and a Na ion or a Li ion, and α Is 0.
01 to 1.99, β to 0.01 to 1.99, α + β to 0.1 to 2, γ to 2 to 3.5, δ to 3 to 4, and a And b each represent 0 to 1 and a + b = 1), which is a synthetic fluorine mica ion exchange product. 4. A mica characterized by adding an inorganic coagulant to a slurry comprising synthetic swellable fluoromica particles and fibers, agglomerating the synthetic fluoromica particles to fix the fibers, and making the paper. Paper manufacturing method. 5. The method for producing mica paper according to claim 4, wherein the synthetic swelling fluoromica is the synthetic swelling fluoromica according to claim 2. 6. The method for producing mica paper according to claim 4, wherein the synthetic swelling fluoromica is the synthetic fluoromica ion exchange product according to claim 3.