JPH04100993A - Non-flammable paper - Google Patents

Abstract

PURPOSE:To provide a non-flammable paper having excellent water resistance and water filterability and useful for wall materials, etc., by processing a slurry containing sepiolite, the first binder comprising a thermosetting resin used for binding the sepiolite and the second binder comprising a thermoplastic resin used for coagulating the sepiolite into the paper. CONSTITUTION:A slurry containing sepiolite such as mountain leather, the first binder comprising a thermosetting resin such as a polyamidepolyamine epichlorohydrin used for binding the sepiolite and the second binder comprising a thermoplastic resin such as polyacryl amide used for coagulating the sepiolite is processed into the objective paper. The mixing of inorganic fibers as a reinforcing material permits to improve the strength and physical properties of the paper.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a noncombustible paper used for wall covering materials, heat-resistant decorative laminate sheets, etc. In particular, the present invention relates to nonflammable paper used as an asbestos substitute paper, and This paper relates to non-combustible paper that also has H water resistance.

[Conventional technology] In recent years, due to social use related to the prevention of fire accidents,
Along with plastics and clothing, issues such as flame retardancy and fire resistance have been raised in building interior materials, etc., and regulations have come to be quite strict. Paper is no exception, and there are many demands in the market for so-called flame-retardant and non-combustible paper, which is ``non-flammable and heat-resistant'', including for wall covering materials.

Conventionally, asbestos fiber paper was the representative inorganic fiber of general-purpose non-flammable paper. This asbestos fiber paper was excellent in all aspects, including flame retardancy, heat resistance, high strength, easy productivity, and low price, and had a wide range of uses, covering areas of application that were difficult to use with organic fibers.

Now, let's talk about the characteristics of asbestos. Normal asbestos is formed from ores such as olivine and pyroxene, which turn into serpentinite and amphibolite into fibers through the hydrothermal action of geothermal heat and groundwater in the earth's crust under high pressure. It is crystallized. Among these, most of the varieties used as raw materials for papermaking are serpentinite-based chrysotile asbestos, whose chemical formula is 3 M g O 2 S r 02 2
It is H20. The fiber diameter is extremely thin, 20 to 40 nm, and is flexible.

It has a low hardness of 2.5 to 4.0, which is why it is used as a wear material. In addition, when paper is made from this, it is compatible with water because it contains crystallized water.

When mixed with other additives, since chrysotile is charged or cationic in water, it has good adsorption and scavenging properties. When made into a paper sheet, this physical property is strong, nonflammable, and soft.
However, asbestos has some advantages as an inorganic fiber, such as being smooth and easy to make, but recently, asbestos has been shown to be harmful to health.
It gradually became unusable in Japan.

It is also almost unusable in Western Europe.

In view of this situation, with the development of new materials, the development of alternative materials similar to asbestos is currently 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 somewhat commonly used. Other types include gypsum fiber, basic magnesium sulfate fiber, phosphate fiber, and magnesium pyroborate fiber. However, the reality is that these fibers have not yet reached the level of being a substitute for asbestos in terms of usage, productivity, price, etc.

Another way to make paper that is flammable is to make it flameproof. This is a method seen in wallpaper, shoji paper, paper heat exchangers, etc., and can be said to be a treatment method that does not cause ignition. The base material is wood pulp paper such as kraft paper impregnated or coated with a flame retardant, which includes ammonium-containing aqueous inorganic salts, phosphorus-containing nitrogen compounds, phosphorus-containing halogen compounds, antimony trioxide-halogen compounds, boron compounds, Halogen compounds and the like are used.

However, this treatment is not completely non-flammable since it is mainly composed of organic substances. Aromatic polyamide fibers are also available as high-performance fibers, but they are not widely used.

Under these circumstances, from a social and industrial standpoint, there is an even stronger demand for the development of using other fibers as substitutes for areas where asbestos fiber paper cannot be used. From a general purpose perspective,
It is useful for various purposes such as wall covering materials, sealing materials, gaskets, para-kink, asphalt roofing, cushion floor-1 noncombustible core, building material covering paper, laminated paper, and insulation materials.

Under these circumstances, attention is being focused on the possibility of using sepiolite as a substitute for asbestos among existing natural fibers. There are also many examples of nonflammable sheets using sepiolite.

Here, sepiolite is commonly known as Mountain Leather (
It is a clay mineral called mountain bark), mountain cork, or mountain wood, and meerschaum in Japan is also a type of this type. The appearance may be cork-like or leather-like,
It may be a pure white soft lump, but it is generally a fibrous lump of magnesium silicate. Although it is classified as a clay with a -dimensional structure, depending on how you look at it, it can be seen as a crystalline three-dimensional structure similar to that of brick masonry, which is easily scraped in a certain direction, and has a crystalline group consisting of silicon, magnesium, oxygen, hydroxyl groups, and crystalline water. is forming. The basic physical properties are adsorption, thixotropy, and solidification.

Examples of paper manufacturing using this characteristic include JP-A-51-88799, JP-A-56-165097, JP-A-58-95636, and JP-A-58-1.
．． 44196, Japanese Patent Application Laid-open No. 59-21800,
JP-A-61-258099, JP-A-63-235
There are techniques disclosed in Japanese Patent Application Laid-Open No. 64-61599, etc.

[Problems to be Solved by the Invention] The above-mentioned publication discloses that inorganic fibers such as ceramic fibers, cloth, that is, organic fibers, or fibers made of both have adsorbability, thixotropy,
It is often mixed and dispersed using sepiolite, which has high caking properties, and then dried. This is because sepiolite is a fine fiber, so when making paper, it has poor drainage properties, making it difficult to form any desired sheet, and it also has poor tear strength. Due to the difficulty of doing so. For this reason, the excellent properties of sepiolite are not fully utilized. However, in JP-A-59-21800, there is only a description of the use of sepiolite fibers alone, and there is no description of specific technical content, so it lacks practicality.

By the way, as mentioned above, wall paper is required to be flame retardant and noncombustible from the standpoint of disaster prevention. On the other hand, in humid countries like ours, building materials absorb moisture and swell, and repeated swelling and drying may cause the wall paper to deform or break. Therefore, in addition to flame retardancy and noncombustibility, water resistance is also required.

On the other hand, in the above publication, there is almost no description of technology related to water resistance. In the above-mentioned Japanese Patent Application Laid-Open No. 5921800, a technique is described in which a small amount of resin such as silicone or Teflon is mixed into an inorganic filter paper to improve water resistance, heat resistance, and chemical resistance, but the application is limited to filtration. It is paper, and the specific technical content is not specified.
As mentioned above, this may lack practicality.

Therefore, an object of the present invention is to provide a low-cost noncombustible paper that is both noncombustible and water resistant.

[Means for Solving the Problems] The nonflammable paper according to claim 1 comprises sepiolite as a main material, a first binder for consolidation made of a thermosetting resin, and a first binder for aggregation made of a thermoplastic resin. It is made by paper-making a slurry containing two binders as essential components.

The noncombustible paper according to claim 2 comprises sepiolite as a main material, inorganic fibers as a reinforcing material, a first binder for consolidation made of a thermosetting resin, and a second binder for aggregation made of a thermoplastic resin. It is made by paper-making a slurry containing a binder as an essential component.

[Function] In claim 1, the paper made by adding the first binder and the second binder to sepiolite is nonflammable and can be manufactured at low cost because the main component is sepiolite, which is an inorganic fiber. In addition, the thermosetting resin of the first binder is a polymer compound with a three-dimensional network structure, and its atoms are connected by strong covalent bonds, so it is stable against water and has a water-resistant property on paper. give. and,
By adding the first binder and the second binder to sepiolite, which has caking properties, the strength of the paper is improved. Furthermore, in claim 2, the second binder is characterized by coagulating the slurry and improving freeness in papermaking to form a sheet. This further improves the strength and physical properties of the paper.

[Example] Hereinafter, an example of the present invention will be described based on FIGS. 1 to 4.

FIG. 1 is an explanatory diagram showing an outline of the manufacturing process of noncombustible paper in one embodiment of the present invention.

In this example, in order to make full use of the characteristics of sepiolite, the content of sepiolite was 80% or more, and a binder and the like were added to form a slurry, which was then made into a paper. Normally, when made sepiolite rich, the freeness is poor in paper making,
It is not possible to make paper of arbitrary thickness. In particular, using a paper machine, 2
Paper weighing less than 00 g/rrr does not match the paper making speed. On the other hand, thin paper around 100 g/rr1'' lacks wet paper strength and has problems in continuous paper making such as mechanical water extraction and conveyance.

In order to overcome this problem, in this development research, we made adjustments to paper stock, improved freeness, improved processing, selected an appropriate binder, and devised and improved appropriate equipment.

First, the manufacturing process of nonflammable paper in this example will be explained.

In the figure, in defibration step 1, sepiolite as the main raw material and glass fiber as a reinforcing material are put into a defibrator and defibrated by stirring to improve the dispersion of the fibers.

Next, in the raw material mixing step 2, defibrated sepiolite, a first binder, a second binder, a softener, a stabilizer, etc. are placed in a mixing tank and mixed to prepare a slurry. The first binder used here is a thermosetting resin having a three-dimensional network structure in order to meet the requirements for structural strength and water resistance, and among these, EPA (polyamide polyamine epichlorohydrin) was used. Further, as the second binder, FAA (polyacrylamide) for aggregation having a molecular weight of 8 million to 10 million and FAA (polyacrylamide) for increasing paper strength having a molecular weight of 800,000 to 1 million were used.

The slurry mixed in the raw material mixing step 2 is bundled in a paper stock aggregation reaction device in a paper stock processing step 3.

The slurry prepared into paper stock in the paper stock processing step 3 is sent to a stock tank, and an accumulation step is carried out to maintain a uniform mixing state at all times to prevent sedimentation or collapse of the prepared paper stock. Enter 4.

Then, the slurry in the accumulation step 4 is pumped up to the metering hopper, and the slurry metered in the metering hopper is led to the papermaking step 5.

In papermaking step 5 of this example, papermaking was performed using a circular mesh paper machine. At this time, the slurry concentration was 0.5 to 1.0%, and the paper machine used a 60 to 80 mesh screen.

In a drying step 6, the wet paper formed by dehydrating the slurry is dried using a steam rotary dryer. The dried molded product is then peeled off from the dryer surface of the steam rotary dryer and formed into a web.

Next, agglomeration of the slurry, which is performed to improve freeness, will be explained.

As the flocculant serving as the second binder, anionic PAA (polyacrylamide) was selected which binds to calcium ions and magnesium ions, which are metal ions in the composition of sepiolite, or cationic substances, and coagulates and binds the fibers. This FAA has a molecular weight of 8 million to 1000
10,000 polymer resins. The bond between sepiolite and PAA is thought to be caused by the repulsion between the magnesium ion of sepiolite and the amide group of FAA, resulting in the formation of a linear bridge structure.

In this development study, we first investigated the blending ratio of FAA.

The processing conditions were: 150 x 150 mm'FII per second;
Using 80 mesh, the raw material was 85% by weight of sepiolite with 15% by weight of glass fiber added as a reinforcing material.
．． 5 g was defibrated and dispersed in 100 ml of water. Cationic EPA (polyamide polyamine epichlorohydrin) was added to each sample in an amount of 2.0% by weight in terms of solid content under fixed conditions, and the amount of PAA was varied as shown in Table 1. The paper density is 2.5g/10100O (0,25
%), and then the freeness was determined by measuring the drainage time of this diluted solution (10,100O).

The results are as shown in the table shown in Figure 2, which shows the changes due to PAA in the noncombustible paper in this example, and the paper to which 0.3% by weight of FAA was added had good freeness, but the clumps were too large. The texture of the paper is poor. Therefore, around 0.2% by weight is preferable.

Next, the addition of a paper strength enhancer and freeness will be described.

FAA (polyacrylamide) having an anionic molecular weight of 800,000 to 1,000,000 was selected as the paper strength enhancer.

As fixing conditions, FAA for flocculation was set at 0.2% by weight, which has good freeness according to the above test, and EPA was set at 2.0% by weight as above. The processing conditions were as described above.

The results are shown in Figure 3. FIG. 3 is a table showing changes in noncombustible paper depending on the addition of a paper strength enhancer and freeness in an example of the present invention.

The FAA used to strengthen paper strength was highly viscous, and No.
If it is 4 or more, the aggregates will gel and the freeness will be poor, so 1.0 to 2.0% by weight is preferable.

Next, trends in physical properties due to increases and decreases in EPA (thermosetting resin) were investigated.

As fixation conditions, FAA (for aggregation) was set at 0.2% by weight, and FAA (for paper strength enhancement) was set at 2.0% by weight. The processing conditions were as described above.

The results are shown in Figure 4. FIG. 4 is a table showing trends in physical properties of noncombustible paper according to examples of the present invention as a result of increases and decreases in EPA.

No. 5 has the highest wet tensile strength, and as EPA, 2.0% by weight is preferable. It should be noted that if it exceeds 2.0% by weight, the amount of organic components increases and the intention of non-flammability is lost, so 2.0% by weight is set as the upper limit.

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

The strength and freeness of this glass fiber were examined by changing the mixing ratio to sepiolite and the fiber length. Specifically, the fiber length was set to 3.6.13 mm, and the mixing ratios were changed to 5.10, 15.20% by weight, respectively.

As a result, the fiber length was 13 mm and the mixing ratio was 15 to 20% by weight, which was the best overall in terms of strength and freeness. It is thought that glass fiber also acts as a filler to promote aggregation.

FIG. 5 shows a comparison example of water resistance between the sample No. 34 in FIG. 4 of the present invention and a commercially available sample (aluminum hydroxide paper made of wood pulp and aluminum hydroxide powder).

FIG. 5 is a table comparing the underwater elongation with nonflammable paper in one embodiment of the present invention.

In the longitudinal direction, there is no difference between the sample of the present invention and the commercially available sample after immersion for 1 hour or 24 hours, but in the lateral direction, the elongation of the sample of the present invention is clearly smaller, and the overall elongation is lower. The samples of the present invention show excellent water resistance.

The reason why the vertical and horizontal elongation of commercially available samples is significantly different is that during paper making, the fibers of wood pulp tend to be oriented vertically, and the degree of entanglement of the fibers increases, resulting in less elongation. This is thought to be due to the fact that the degree of entanglement of the fibers is small, so the elongation is large.

On the other hand, the samples of the present invention do not use wood pulp, are mainly made of sepiolite, and have relatively short fiber lengths, so the fiber directionality is small and the bundled fibers are made of fine glass fibers. It is thought that the difference between the vertical and horizontal dimensions is small because of the formation of .

In this way, the noncombustible paper of the above example has sepiolite as a main material, glass fiber as an inorganic fiber as a reinforcing material, and a first binder made of EPA (polyamide polyamine epichlorohydrin) as a thermosetting resin. , a slurry containing as an essential component a second binder made of PAA (polyacrylamide), which is a thermoplastic resin, is made into paper.

Therefore, according to the above embodiment, sepiolite has a first
Paper made by adding a binder and a second binder is
Since the main component is sepiolite, which is an inorganic fiber, it is nonflammable. In addition, EPA, which is the thermosetting resin of the first binder, is a polymer compound with a three-dimensional network structure, and its atoms are connected by strong covalent bonds, so it is stable against water and paper can be made water resistant.

Furthermore, by adding the first binder and the second binder to sepiolite, which has caking properties, the strength of the paper can be improved.

Furthermore, the second binder PAA causes the slurry to coagulate,
Improves freeness in papermaking to facilitate sheet formation.

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

Furthermore, since widely used materials are used as raw materials and binders, it can be manufactured at low cost.

By the way, although the noncombustible paper of the above-mentioned example contains glass fiber mixed as a reinforcing material, it is not necessarily necessary to mix the reinforcing material depending on the intended use.

In the embodiment of this type of 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 feel to noncombustible paper, which has a hard feel due to glass fibers being mixed therein.

Further, the first binder made of a thermosetting resin in the above example uses polyamide polyamine epichlorohydrin, and the second binder made of a thermoplastic resin uses polyacrylamide, but it is possible to carry out the present invention. In this case, the resin is not limited to this, and other resins can also be used. The thermoplastic resin and the thermosetting resin may each use one type of resin, or two or more types of resin may be mixed.

The mixing ratio of sepiolite, reinforcing material, first binder, and second binder in the above example is not limited to this, and the optimum ratio should be selected depending on physical properties, freeness, manufacturing method, application, etc. Bye.

The noncombustible paper of the present invention can be used for wall covering materials, sealing materials, architectural covering paper, etc., but it can also be applied to both sides of a heat insulating material to prevent the fibers of the heat insulating material from forming. It can also be used to prevent flaking and flaking. Alternatively, they can be laminated to form a heat insulating material, and can also be used as an insulating material.

Further, the molded product can be made into a paper having a thickness of about 10 mm, and can be used, for example, as a noncombustible board. Furthermore, since it is possible to form the paper into an uneven shape, it can also be used as a three-dimensional noncombustible material.

[Effects of the Invention] As described above, the noncombustible paper of the invention of claim 1 includes sepiolite as a main material, a first binder for consolidation made of a thermosetting resin, and a first binder for aggregation made of a thermoplastic resin. A slurry containing a second binder as an essential component is made into paper. Therefore, paper made by adding a first binder and a second binder to sepiolite has nonflammability and can be produced at low cost because the main component is sepiolite, which is an inorganic fiber. In addition, the thermosetting resin of the first binder is a polymer compound with a three-dimensional network structure, and the atoms are connected by strong covalent bonds, so it is stable against water and provides water resistance to paper. can be given. Furthermore, by adding the first binder and the second binder to sepiolite, which has caking properties, the strength of the paper can be improved. Furthermore, the thermoplastic resin of the second binder coagulates the slurry and improves freeness during papermaking.・Facilitate the formation of

The nonflammable paper according to the second aspect of the invention is obtained by adding inorganic fibers as a reinforcing material to the components of the slurry according to the first aspect. Therefore, in addition to the effects of claim 1, the strength and physical properties of paper can be further improved.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an outline of the manufacturing process of noncombustible paper in one embodiment of the present invention. FIG. 2 is a table showing changes according to FAA of non-combustible paper in one embodiment of the present invention. FIG. 3 is a table showing changes in noncombustible paper depending on the addition of a paper strength enhancer and freeness in an example of the present invention. FIG. 4 is a table showing trends in physical properties of noncombustible paper according to an increase or decrease in EPA in an embodiment of the present invention. FIG. 5 is a table comparing the elongation in water of the non-combustible paper according to an example of the present invention and commercially available non-combustible paper. In the figure, 1: Defibration process 3: Paper processing process 5: Paper making process. 2. Raw material mixing process 4. Accumulation process 6: Drying process Patent applicant Tokiwa Electric Co., Ltd. Patent attorney Takehisa Higuchi and 1 other person

Claims (2)

[Claims] (1) It is made by paper-making a slurry whose essential components are sepiolite as the main material, a first binder for consolidation made of a thermosetting resin, and a second binder for aggregation made of a thermoplastic resin. Characteristic nonflammable paper. (2) Sepiolite as the main material, inorganic fiber as a reinforcing material, a first binder for consolidation made of a thermosetting resin, and a second binder for aggregation made of a thermoplastic resin are essential components. Nonflammable paper characterized by being made from slurry.