JPH0625995A - Incombustible sheet - Google Patents

Abstract

PURPOSE:To provide incombustibility and water resistance to a sheet and improve producibility and enable low-cost sheet making due to mass production by using sepiolite as a main raw material. CONSTITUTION:The incombustible sheet is obtained by making slurry consisting essentially of the first binder composed of sepiolite as a main material, glass fiber which is an inorganic fiber as a reinforcement and polyacrylamide which is a thermoplastic resin and the second binder composed of polyamidepolyamine epichlorohydrin which is a thermosetting resin into a sheet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-combustible sheet used for wall coverings, heat-resistant decorative sheet, etc., and particularly, it has non-combustibility and heat resistance as a substitute for asbestos.
The present invention relates to a nonflammable sheet having excellent productivity.

[0002]

2. Description of the Related Art In recent years, due to social needs related to prevention of fire accidents, problems such as fireproofing and fireproofing of interior materials such as plastics and clothing have come to be regulated considerably. . Sheets such as paper are no exception to this, and there are many market demands for so-called flameproof / noncombustible sheets, such as wall coverings, that do not burn or resist heat. Heretofore, asbestos fiber paper has been typified as the inorganic fiber as the general-purpose non-burnable paper. This asbestos fiber paper excels in all aspects such as flame retardancy, heat resistance, high strength, easy productivity, and low price. It covers a range of applications that are difficult for organic fibers and has a wide range of uses.

[0003] As for the characteristics of asbestos, ordinary asbestos becomes ores such as olivine and pyroxene as serpentine and amphibolite due to the geothermal and hydrothermal effects of groundwater in the crust under high pressure. It is a fibrous crystal. Among them, most of the varieties used as raw materials for papermaking are chrysotile asbestos of the serpentine series, the chemical formula of which is 3MgO · 2SiO ₂ · 2H.
₂ O. The fiber diameter is 20 to 40 nm, which is extremely thin and flexible. The hardness is as low as 2.5 to 4.0, which is why it is used as a wear material. Also, when making paper from this,
As it contains crystal water, it has good compatibility with water. In the case of mixing with other additives, chrysotile has good adsorption and scavenging properties because the charge in water is cation. These physical properties of a paper sheet are advantageous as an inorganic fiber such as strong, non-flammable, soft, smooth and easy to make.

However, recently, asbestos has a harmful effect on health, so that it has gradually become unusable in Japan. In Western Europe, it is almost unusable.

From this situation, with the development of new materials, the development of alternative materials similar to asbestos is being actively researched in various places, and high-performance inorganic fibers or whiskers are being developed one after another. For example, pitch-based general-purpose carbon fibers, potassium titanate fibers, alumina-silica fibers, glass fibers and the like are used rather widely. In addition, gypsum fiber, basic magnesium sulfate fiber, phosphoric acid fiber, magnesium pyroborate fiber and the like are also available. However, in reality, these fibers have not reached the level of alternatives to asbestos in terms of use, productivity, price, etc.

[0006] In addition, there is a flameproofing method as a method for producing a paper that is difficult to burn. This is a method found in wallpaper, shoji paper, paper heat exchangers, etc., and can be said to be a treatment method that does not ignite.
The base material is one obtained by impregnating or coating a wood pulp paper such as kraft paper with a flameproofing agent, an ammonium-containing salt type aqueous inorganic salt, a phosphorus-containing nitrogen compound, a phosphorus-containing halogen compound, an antimony trioxide-halogen compound, a boron compound, A halogen compound or the like is used. However, this treatment is mainly organic matter after all and cannot be said to be completely nonflammable. Aromatic polyamide fibers are also used as high-performance fibers, but they are not widely used.

Under these circumstances, there is a strong demand from a social and industrial point of view to develop a surface that cannot use asbestos fiber paper by using another fiber. From a general-purpose application, there is a need for a wide range of applications such as wall coverings, sealing materials, gaskets, packing, asphalt roofing, cushion floors, incombustible cores, building material covering paper, laminated paper, and heat insulating materials.

[0008] Under these circumstances, the possibility of using sepiolite as an alternative to asbestos among the existing natural fiber products is drawing attention. There are also many cases of non-combustible sheets that use sepiolite.

Here, sepiolite is a clay mineral commonly referred to as mountain leather, mountain cork, and mountain wood, and sepiolite in Japan is also a kind of this. The appearance may be cork-like, leather-like, or a pure white soft lump, but it is generally a magnesium silicate lump having fibrous properties. For the time being, although it is classified as a one-dimensional structure clay, it can be considered as a crystalline three-dimensional structure of bricks that can be easily shaved in a certain direction depending on the viewpoint, and a crystal form group consisting of silicon, magnesium, oxygen, hydroxyl group, and crystal water is Is forming. Physical properties have basic properties such as adsorption, thixotropy, and solidification.

Examples of papermaking using this characteristic include, for example, Japanese Patent Laid-Open Nos. 51-88799 and 56-1.
65097, JP-A-58-95636, JP-A-58-144196, JP-A-59-2180.
No. 0, JP 61-258099 A, JP 6
There are techniques disclosed in JP-A-3-235600, JP-A-64-61599 and the like.

[0011]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the publication mentioned in the non-combustible sheet, the inorganic fiber such as ceramic fiber or cloth, that is, the organic fiber or the fiber composed of both of them is adsorbable, thixotropic, and caking. In many cases, it was mixed, dispersed, treated, and dried with the help of sepiolite, which is rich in water. This is because sepiolite is a fine fiber,
In the case of papermaking, the drainage is poor, and the ratio of raw materials to raw materials added to a slurry generally composed of wood pulp, synthetic fibers, inorganic fibers, etc. having a good drainage of 0.01 to
This is because it is difficult to form an arbitrary sheet with the amount of the coagulant added of 0.1%, and it is difficult to make paper from sepiolite as a main raw material because of the poor tear strength.
Even if the amount of the aggregating agent added is 0.1% or more with respect to the raw material, not only the drainage performance is not improved, but also the excessive addition increases the viscosity of the slurry and rather deteriorates the papermaking property. For this reason, in the past, even in the case of small-scale production in a laboratory, industrial production in conformity with the mass production base was extremely difficult, and the excellent properties of sepiolite were not fully utilized. Slightly, JP-A-59-
In Japanese Patent No. 21800, there is a description of using sepiolite fiber alone, but there is no description of specific technical contents, and it is not practical.

[0012]

A non-combustible sheet according to a first aspect of the present invention comprises a sepiolite as a main material, a first binder for fixing made of a thermoplastic resin, and a cohesive, water-resistant sheet made of a thermosetting resin. It is made by making a slurry containing a second binder as an essential component.

A non-combustible sheet according to a second aspect of the present invention comprises sepiolite as a main material, a first binder for fixing which is an anionic thermoplastic resin, and an agglomerating and water-resistant resin made of a cationic thermosetting resin. The second binder, the third agglomerating binder made of an anionic thermoplastic resin, and the fourth agglomerating binder made of a cationic thermoplastic resin are made into papers as essential components. .

A nonflammable sheet according to a third aspect is obtained by adding the inorganic fiber as a reinforcing material as an essential component to the slurry according to the first or second aspect.

[0015]

According to the first aspect of the invention, the sheet made by adding the first binder and the second binder to sepiolite is
Since the main component is sepiolite, which is an inorganic fiber, it has noncombustibility and can be manufactured at low cost. Moreover, the thermoplastic resin of the first binder contributes to the fixing property of sepiolite and improves the strength of the sheet. Further, EPA, which is a thermosetting resin of the second binder, is a polymer compound having a network-like three-dimensional structure, and since the atoms are bound by strong covalent bonds, it is stable to water and is stable on paper. To provide water resistance to the sheet and improve drainage during papermaking to facilitate the formation of a sheet.

According to the second aspect of the present invention, after adding the first binder and the second binder, the floc is coarsened by adding the third binder which is an anionic flocculant to the cation side slurry. . Next, when a fourth binder, which is a cationic flocculant, is added, the flocs become hydrophobic and become strong. This further improves drainage.

Further, in the third aspect, in addition to the action of the first or second aspect, the strength physical properties of the sheet are further improved by mixing the inorganic fiber as the reinforcing material.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is an explanatory view showing an outline of a manufacturing process of a nonflammable sheet in one embodiment of the present invention.

In this example, in order to make the best use of the characteristics of sepiolite, sepiolite was made to be 80% or more, and a binder or the like was added to this to make a slurry, and papermaking was carried out. Usually, when sepiolite rich is used, the drainage is poor in papermaking, and paper of any thickness cannot be made. In particular, using a paper machine, a machine weighing 200 g / m ² or more does not match the paper making speed. On the other hand, the thin paper around 100 g / m ²
There is no wet paper strength, and there is a problem with continuous paper making properties such as water squeezing and conveyance by machines.

In order to overcome this problem, in the present development research, paper stock adjustment, drainage, improvement treatment, selection of an appropriate binder, devising of an appropriate device, improvement, etc. were carried out.

First, the manufacturing process of the nonflammable sheet in this embodiment will be described.

In the figure, in the defibration step A, sepiolite as a main raw material, glass fiber as a reinforcing material, wood pulp as a reinforcing fiber, and synthetic fiber are put into a defibrating machine and defibrated by stirring to disperse the fibers. Improve In this example, if the amount of wood pulp is 5% by weight or more, nonflammability will be impaired, so the amount is limited to 5% by weight or less.

Next, in the raw material mixing step B, the disentangled sepiolite, the first binder, the second binder, the softening agent,
Stabilizers are put in a mixing tank and mixed to prepare a slurry. The first binder used here is PAA (polyacrylamide) having a molecular weight of 800,000 to 1,000,000, which is a thermoplastic resin, in order to increase the paper strength, and the second binder imparts cohesiveness and water resistance. Therefore, a thermosetting resin having a three-dimensional network structure was used, and EPA (polyamide polyamine epichlorohydrin) was used among them.

Here, the order of adding the respective binders is that the first binder is added first, and then the second binder is added.
It is desirable to add a binder, but the binder is not necessarily limited to this, and it is possible to make paper by mixing the second binder first and the first binder later.

The slurry mixed in the raw material mixing step B is
In the processing step C, the paper stock is made into a bundle by a bundle focusing reaction device. In the bundling, in order to promote the fixing of the first binder and the second binder to the slurry and to improve the drainage property at the time of papermaking, the molecular weight is 8,000,000 to 1,000.
Tens of thousands of anionic PAAs were added.

The slurry prepared as a stock in the processing step C is sent to a stock tank and accumulated so that the mixed state is always made uniform so that sedimentation separation or disintegration of the prepared stock does not occur. Enter the process D.

Then, the slurry uniformly maintained in the accumulation step D is pumped up by a metering pump into a metering hopper,
The slurry measured by the quantitative hopper is guided to the papermaking process E.

In the papermaking process E of this example, papermaking was performed using a short-net paper machine. The slurry concentration at this time is 0.5 to
1.0%, and the short-net paper machine used a 60-80 mesh net. In this papermaking step E, when the dispersed aqueous solution in which flocs are formed is flown into a papermaking machine having a mesh of about 80 mesh from above, water quickly flows down from the nets through the flocs to form a paper layer. It

Then, in the drying step F, the paper layer is dehydrated by pressing and dried at an ambient temperature of about 120 ° C. for a predetermined time, whereby the water content in the paper layer is evaporated and the binder is condensed. Is accelerated and dried and solidified. Then, the dried molded body is peeled off from the dryer surface of the steam rotary dryer to form a roll paper.

As described above, a nonflammable sheet having a plate thickness of 0.1 to 1.0 mm is completed. This non-combustible sheet has high heat resistance, and even if a fire is approached, only a slight amount of smoke and blackening can be maintained and a predetermined shape can be maintained.

Next, the bundling of the slurry to improve drainage will be described. As the aggregating agent, the above-mentioned anionic PAA that aggregates and binds with the fibers by binding with calcium ions or magnesium ions which are metal ions in the composition of sepiolite or a cation substance was selected. It is considered that the bond between sepiolite and PAA is such that a magnesium ion of sepiolite and the amide group of PAA repel each other to form a linear bridge structure.

In the present development study, first, the blending ratio of PAA was examined.

The processing conditions are as follows: paper making tool 150 × 150 mm
Size, 80 mesh, and raw material is Sepiolite 85
15% by weight of glass fiber was added to the weight% as a reinforcing material, and 2.5 g of this was disintegrated and dispersed in 100 ml of water. To this, cationic EPA (polyamide polyamine epichlorohydrin) was added as a fixed condition to each sample in an amount of 2.0% by weight in terms of solid content, and the compounding amount of PAA was changed as shown in FIG. The papermaking concentration is 2.5 g / 1000 ml (0.25
%), And then the freeness was judged by measuring the freezing time of 1000 ml of this diluted solution.

The results are shown in the table of FIG. 2, which shows the change due to PAA of the non-combustible sheet in one embodiment of the present invention.
Draft with 0.3% by weight of PAA has good drainage, but the bundles are too large and the texture of paper is poor. Therefore, 0.
Around 2% by weight is good.

Next, the addition of the paper strengthening agent and the drainage will be described.

PAA having a molecular weight of 800,000 to 1,000,000 which is an anion of the first binder as a paper-strengthening agent as described above.
(Polyacrylamide) was selected.

As fixing conditions, PAA for flocculation was 0.2 wt% with good drainage by the above test, and EP
A was 2.0% by weight as above. The processing conditions were the same as above.

The results are shown in FIG. FIG. 3 is a table showing the change of the non-combustible sheet in one embodiment of the present invention due to the addition of the paper strength enhancer and the drainage.

The tested paper strength increasing PAA has a high viscosity, and when it is No. 4 or more, the aggregate is gelled and the drainage is not good, so 1.0 to 2.0% by weight is preferable.

Next, the tendency of physical properties due to increase and decrease of EPA (thermosetting resin) was examined.

As a fixed condition, PAA (for aggregation) was 0.
2% by weight, and PAA (for strengthening paper strength) was 2.0% by weight. The processing conditions were the same as above.

The results are shown in FIG. FIG. 4 is a table showing the physical property tendency of the non-combustible sheet according to one embodiment of the present invention as the EPA increases and decreases.

No. 5 has the highest wet tensile strength and is EPA
Is preferably 2.0% by weight. It should be noted that when the content exceeds 2.0% by weight, the amount of organic components increases and it deviates from the intent of non-combustion, so 2.0% by weight was set as the upper limit.

By the way, in this test, in order to further improve the paper strength, glass fiber as a reinforcing material is added.

With respect to this glass fiber, the mixing ratio to sepiolite and the fiber length were changed, and the strength and drainage were examined. Specifically, the fiber length is set to 3, 6, 13 mm, and the mixing ratio is 5, 10, 15, 20 for each.
Changed to% by weight.

As a result, the fiber length was 13 mm and the mixing ratio was 1.
Those having 5 to 20% by weight were the best in comprehensively comparing strength and drainage. It is considered that glass fiber also has a function of promoting aggregation as a filler.

Regarding the water resistance, FIG. 4 No. of the embodiment of the present invention.
FIG. 5 shows an example in which the sample of No. 4 and a commercially available sample (aluminum hydroxide paper made of wood pulp and aluminum hydroxide powder) are compared.

FIG. 5 is a table comparing the elongation in water with the noncombustible sheet in one example of the present invention.

Regarding the longitudinal direction, there is no difference between the sample of the example of the present invention and the commercially available sample after both 1-hour immersion and 24-hour immersion, but in the horizontal direction, the sample of the example of the present invention. The elongation of the samples is obviously small, and the samples of the examples of the present invention show excellent water resistance.

In the commercially available sample, the longitudinal and lateral elongations are remarkably different from each other because the fiber orientation of wood pulp is easily aligned in the longitudinal direction during papermaking, and the degree of entanglement of fibers increases and the elongation decreases. On the other hand, it is considered that the elongation is large in the horizontal direction because the degree of entanglement of fibers is small.

On the other hand, the samples of the examples of the present invention did not use wood pulp, and since sepiolite was the main material and the fiber length was relatively short, the fiber orientation was small and fine glass fibers were formed. Since it forms an integrated bundle of fibers,
It is considered that the difference between the vertical and horizontal directions has become smaller.

As described above, the non-combustible sheet of the above-described embodiment has sepiolite as the main material, glass fiber as the inorganic fiber as the reinforcing material, and PAA as the thermoplastic resin.
It is made by making a slurry containing a first binder made of (polyacrylamide) and a second binder made of EPA (polyamide polyamine epichlorohydrin) which is a thermosetting resin as essential components.

Therefore, according to the above embodiment, the paper made by adding the first binder and the second binder to sepiolite has nonflammability because the main component is sepiolite, which is the inorganic fiber. Further, PAA of the first binder contributes to the fixing property of sepiolite and can improve the strength of the paper.

Further, EPA, which is the thermosetting resin of the second binder, is a polymer compound having a network-like three-dimensional structure, and the atoms are bound by strong covalent bonds, so that it is stable to water. In addition, it imparts water resistance to the paper and improves drainage in papermaking to facilitate sheet formation.

By mixing glass fiber as a reinforcing material, the strength and physical properties can be further improved.

Since the widely used materials are used as the raw material and the binder, it can be manufactured at low cost.

In this embodiment, claims 1 and 3 are provided.
It corresponds to the embodiment of.

Next, another embodiment will be described.

In this another embodiment, a cationic thermoplastic resin is added to the aggregating PAA which is the first binder, the second binder and the anionic thermoplastic resin of the above embodiment, and the aggregating PAA ( Molecular weight 8 million to 1000
10,000) as the third binder and the cationic thermoplastic resin as the fourth binder.

The third binder and the fourth binder act as an aggregating agent, and the flocs are further coarsened with respect to those obtained by fixing and aggregating by adding the first binder and the second binder described in the above embodiment. It is possible to improve the papermaking property. That is, in the raw material mixing step B,
After adding the first binder and the second binder in the same manner as in the above example, the third binder, which is an anionic thermoplastic resin, is mixed with the slurry which is the cation side to coarsen the flocs, and then the cation. A strong floc can be formed by adding a fourth binder, which is a coagulant of the system, into a hydrophobic floc.

The third binder may be, for example, AA (acrylamide / acrylic acid copolymer) in addition to the above-mentioned flocculating PAA, and the fourth binder may be, for example, DMAEM (dimethylaminoethyl). Methacrylate) can be mentioned.

The blending amount of each binder is such that the first binder is 2% by weight or less in terms of solid content, the second binder is 2% by weight or less, and the third binder and the fourth binder are 0.2 to 1 in total in solid content of raw materials. 0.0% by weight, and the ratio of the third binder in the third binder and the fourth binder is 2
It is preferably 5 to 75%.

Also in this embodiment, the addition order of the first binder and the second binder is preferably such that the first binder is first and the second binder is second, but the order may be reversed, and the third binder may be added. Also in the order of addition between the binder and the fourth binder, the third binder is desirable first, but the reverse is also possible for papermaking.

Although this another embodiment corresponds to the aspect of claim 2, it can also be considered to correspond to the aspect of claim 3.

By the way, in the above embodiment, the first binder made of the thermoplastic resin is PAA, the second binder made of the thermosetting resin is EPA, the third binder made of the thermoplastic resin is AA, and the thermoplastic resin is the thermoplastic resin. DMAEM is used as each of the fourth binders consisting of, but the present invention is not limited to this, and other synthetic polymers and natural polymers can also be used. And the resin used for each thermoplastic resin and thermosetting resin may be one kind respectively, or two or more kinds may be mixed.

Further, the sepiolite in the above embodiment,
The mixing ratio of the aggregating agent, the reinforcing material, the reinforcing fiber, etc. is not limited to the ratio shown in the examples, and an optimum one may be selected depending on the physical properties, drainage, manufacturing method, application and the like.

Further, the non-combustible sheet of the above-mentioned embodiment is mixed with glass fiber as a reinforcing material. However, the present invention is not limited to this, and rock wool fiber, stainless fiber, Various reinforcing materials such as whiskers can be used. However, glass fiber is most suitable in terms of material cost, aggregation effect, and the like. Depending on the intended use, it is not always necessary to mix the reinforcing material. In this embodiment of the invention, the step of mixing the reinforcing material can be omitted and the work can be simplified. In addition, it is possible to give a smooth texture to a non-combustible sheet that is hard by mixing glass fibers. Similarly, it is not always necessary to mix the wood pulp as the reinforcing fiber and the synthetic fiber, and they may be appropriately used in consideration of paper-making properties, intended use and the like.

The non-combustible sheet of this embodiment can be used as a wall covering material, a sealing material, a building surface covering paper, etc.
In addition, it can be used by preventing the fibers of the heat insulating material from fluffing or peeling off by sticking it to both sides of the heat insulating material. Alternatively, it can be used as an insulating material.

Further, since the nonflammable sheet can be made into a paper having a thickness of about 10 mm and further can be made into a concavo-convex shape, it can be used as a three-dimensionally shaped nonflammable material.

[0071]

As described above, the non-combustible sheet of the first aspect of the present invention comprises sepiolite as a main material, a first binder for fixing made of a thermoplastic resin, and an agglomerate, water resistant material made of a thermosetting resin. A second binder for use is made into paper by making a slurry containing the essential component. Therefore, the sheet produced by adding the first binder and the second binder to sepiolite has the non-flammability and can be manufactured at a low price because the main component is sepiolite. Moreover, the thermoplastic resin of the first binder contributes to the fixing property of sepiolite and improves the strength of the sheet. Furthermore, EPA, which is a thermosetting resin for the second binder
Is a polymer compound with a three-dimensional network structure and its atoms are bound by strong covalent bonds, so it is stable to water, imparts water resistance to paper, and improves drainage in papermaking. To facilitate the formation of the sheet.

Further, the nonflammable sheet according to the invention of claim 2 is
Sepiolite as a main material, a first binder for fixation composed of an anionic thermoplastic resin, a second binder for aggregation and water resistance composed of a cation thermosetting resin,
This is made by paper-making a slurry containing a third aggregating binder made of an anionic thermoplastic resin and a fourth agglomerating binder made of a cationic thermoplastic resin as essential components. Therefore, when the third binder, which is an anionic flocculant, is added to the slurry that is the cation side after adding the first binder and the second binder, the flocs become coarse, and then the flocculant is a cationic flocculant. When the fourth binder is added, the flocs become hydrophobic and become strong. This further improves drainage.

Further, the nonflammable sheet of the invention of claim 3 is
An inorganic fiber as a reinforcing material is added as an essential component to the slurry according to claim 1 or 2. Therefore, the strength and physical properties of the sheet can be further improved.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an outline of a manufacturing process of a non-combustible sheet according to an embodiment of the present invention.

FIG. 2 is a table showing changes due to PAA of a nonflammable sheet in an example of the present invention.

FIG. 3 is a table showing changes due to addition of a paper strength enhancer and drainage of a non-combustible sheet in one example of the present invention.

FIG. 4 is a table showing physical property trends due to increase / decrease in EPA of a nonflammable sheet in an example of the present invention.

FIG. 5 is a table comparing the underwater elongations of a non-combustible sheet and a commercially available non-combustible sheet in one example of the present invention.

[Explanation of symbols]

 A defibration process B raw material mixing process C treatment process D accumulation process E papermaking process F drying process

[Procedure amendment]

[Submission date] June 24, 1993

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 5

[Correction method] Change

[Correction content]

[Figure 5]

Claims (3)

[Claims] 1. A slurry containing, as essential components, sepiolite as a main material, a first binder for fixation made of a thermoplastic resin, and a second binder for aggregation and water resistance made of a thermosetting resin is made into paper. Non-combustible sheet characterized by being. 2. Sepiolite as a main material, and a first binder for fixing which is made of an anionic thermoplastic resin,
The second for aggregation and water resistance, which consists of a cationic thermosetting resin
It is characterized in that a slurry is made into paper by using a binder, a third binder for aggregation made of an anionic thermoplastic resin, and a fourth binder for aggregation made of a cationic thermoplastic resin as essential components. Non-combustible sheet. 3. The inorganic fiber as a reinforcing material is added to the slurry as an essential component to the slurry.
Alternatively, the nonflammable sheet according to claim 2.