JPS5898495A - Calcium silicate paper and production thereof - 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 The present invention relates to an 8AFi calcium silicate paper and a method for producing the same.

Paper is currently used in a wide range of fields, but its drawback is that it is easily flammable. If paper could be made non-flammable or flame-retardant, it would not only open up new fields, but would also be extremely advantageous in its current fields of use. For this reason, there is a strong demand for imparting nonflammability or flame retardancy while maintaining the various elements required for paper.

The object of the present invention is to meet the above-mentioned needs, and the object of the present invention is to satisfy the above-mentioned needs. A large number of secondary particles of calcium silicate selected from fibrous materials are intertwined and connected in a compressed deformed state, and the content of calcium silicate is 50% on the surface of the plate. This is achieved by providing a calcium silicate paper that exhibits a percent cracking resistance.

The calcium silicate paper of the present invention is excellent in the following points. A large number of secondary particles made of calcium silicate are compressed and deformed while being entangled with fibrous substances, and are connected in nine states. In this compressed and deformed state, the shape of the secondary particles is considerably flattened and remains, to the extent that the secondary particles have been compressed and deformed so much that they have become almost flattened and the original secondary particles are It is included in a state at which is deformed to such an extent that the shape of #1 is hardly left. As described above, the calcium silicate paper of the present invention can be deformed in a wide variety of ways, from deformation to such an extent that the shape of the secondary particles still remains, to deformation that has been significantly compressed to the extent that the shape of the secondary particles hardly remains. The deformed state is included in the range.

Then the second 4! of the paper of the present invention! Specifically, the content of calcium silicate is 50% by weight or more. The paper of the present invention is characterized in that calcium silicate is the main raw material and is not used as a paper filler, and its content is more than 50% by weight, and the fibrous material is only an auxiliary raw material. be.

According to research conducted by the present inventor, the content of fibrous substances is 4.
It has been found that when the weight is less than 0 weight, especially less than 30 weight, the strength of the paper obtained varies depending on the type of calcium silicate used. In particular, in the case of calcium silicate or gyrolite, the strength of the paper obtained is greatly reduced, so gyrolite is not used in the present invention. It has also been found that when the calcium silicate is from the wollastonite group, paper having excellent strength can be obtained almost regardless of the content of fibrous substances.

The third feature of the paper of the present invention is that the state of connection between the secondary particles and the fibrous material is defined by the following points. First, when the paper of the present invention is wound with a curvature of 10 mmR, no cracks occur on its surface. In this case, the cracking is essentially a state in which the intertwined connection state of calcium silicate crystals or quasi-crystals is broken. This feature indicates the flexibility or pliability of the paper of the present invention.

The paper of the present invention preferably has the following percentage ratio.

That is, the tearing length in the paper making direction is 0.3 Km or more. The breaking length at the ship's side is determined by the following formula: Although the paper of the present invention has considerable flexibility or pliability, it also has a considerable resistance to tension under a certain degree of tension, and It shows that you are not lazy.

Further, the paper of the present invention has the following properties.

First of all, its thickness is usually less than 1 m, and its basis weight is 4.
001/l or less. Another advantage is that calcium silicate is preferentially oriented, which means that it can maintain relatively high strength. When the paper of the present invention was irradiated with X-rays and the degree of preferential orientation of calcium silicate crystals was measured by the change in the intensity of the diffraction peak of a specific plane, the bottom plane diffraction intensity of the (001) plane was abnormally high, indicating that the preferential orientation was It was confirmed that Moreover, this diffraction intensity varied depending on the pressure of the roll press during papermaking or the thickness of the unit layer formed during papermaking.

Incidentally, the degree of preferential orientation (P) of the sheet dried calcium silicate crystal shown in the present invention is measured by the following method.

A part of the molded body was collected and finely pulverized, and this fine powder 1f, Lakeside cement 0.21, and pentadioxane 5c
c. thoroughly mixed and stirred while heating at about 80°C,
Evaporate the solvent. The residue is then ground in a mortar, thereby creating a non-oriented powder sample.

xl from the molded body whose preferential orientation degree (P) is to be measured
Another sample is prepared with a specific surface to which s is irradiated, for example, a surface perpendicular to the compression direction.

The diffraction intensities of the (320) and (001) planes of these two samples are measured, respectively. The preferred degree of orientation (P) is given by the following formula.

In preparing the calcium silicate paper of the present invention, a fibrous material is added to an aqueous slurry in which known secondary particles of calcium silicate crystals are dispersed in water, and the resulting paper is mixed with calcium silicate crystals. The paper is made so that the content of is 50 weight or more.

Secondary particles made of calcium silicate, which is the main raw material for the paper of the present invention, or a slurry made by dispersing the same in water, were already well known prior to the filing of this application; for example,
No. 43494, No. 8s53-12526, Special Publication No. 5
No. 3-18533, Special Publication No. 54-4968% Special Publication No. 5
An example of this is the one described in Japanese Patent No. 5-29952.

A slurry made of secondary particles prepared by a method other than the stirring method can also be used. For example, a raw material slurry may be subjected to a hydrothermal reaction in an autoclave without stirring, and if necessary, it may be slightly pulverized. Calcium silicate secondary particles are basically a large number of calcium silicate entangled three-dimensionally to form approximately spherical secondary particles.
Numerous whiskers based on calcium silicate protrude from its surface.

In addition, primary particles of calcium silicate, which are mainly secondary particles, are mixed, which is good. At least one type of calcium silicate selected from the group of wollastonite group, tobermolite group, tricalcium silicate hydrate, and a-dicalcium silicate hydrate is used as the calcium silicate.

According to the research conducted by the present inventor, the following has become clear.

(4) When preparing calcium silicate paper, the physical properties required for the resulting paper, including various mechanical strengths, vary considerably depending on the type of calcium silicate used, and the above four types of calcium silicate are particularly superior. Show physical properties.

In particular, gyrolite has extremely low mechanical strength.

(6) The paper obtained from the wollastonite family of calcium silica has excellent mechanical strength.

(b) Variations in the mechanical strength of the paper obtained, that is, the difficulty that even a single sheet of paper has significant differences in strength depending on the location, also depends on the type of calcium silicate used.
This is particularly noticeable when gyrolite is used, but there is very little variation among the four types of calcium silicate used in the present invention.

Therefore, in the present invention, the above-mentioned four types of calcium silicates are used in principle, and this makes it possible to obtain excellent paper.
Flame retardant paper with physical properties can be obtained.

Specific examples of the 7-7X tonite group include sheetedride, phoshagite, and β-wollastonite, and specific examples of the topelmolite group include tobermolai) and 08H(I). However, tobermolite gel is not used.

In other inventions, sodium, calcium silicates and pectolite can also be used.

As the fibrous material, one or more types of organic fibers and inorganic fibers are used, and the former is c), and in addition to cellulose fibers, various synthetic border lines such as polyamide, polyester, and polyolefin are used, and the latter is c). Glass fiber, rock wool, asbestos, silica fiber, ceramic! Examples include fiber, carbon fiber, and inorganic rice strength. When the fibrous material is added to the cough calcium silicate crystal slurry, it is preferably beaten and fibrillated, and then
Add so that the content is lower than that of calcium silicate crystals. The paper making operations, conditions, etc. that have been conventionally used can be applied as they are, and sizing agents and other additives can be added as appropriate. Examples of additives in this case include paper strength enhancers, water injection agents, moisture-resistant resins, synthetic rubber latex, and flame retardants.These additives may be mixed, impregnated, or Easily added by coating.

In the production method of the present invention, the secondary particles of calcium silicate described above are used as raw materials, and the large contact area based on the large surface area of these particles makes it extremely easy to mix fibrous materials. There is an advantage that the calcium crystals do not separate from the fibrous material and precipitate, and the resulting paper has a uniform texture. In addition, in the production method of the present invention, calendering after papermaking produces smooth and dense paper, and further supercalendering imparts gloss to the surface, resulting in beautiful paper.

The calcium silicate paper of the present invention is not only nonflammable or flame retardant and has excellent disaster prevention properties, but also has excellent adsorption properties, heat insulation properties, electrical insulation properties, and workability, so it is superior to conventionally used flame retardant disaster prevention wallpapers. It can also be effectively used for applications such as ceiling materials, honeycomb core materials, cushion floor materials, industrial insulation materials, backing materials, electrical insulation materials, air conditioning heat exchanger fabric elements, gas adsorption sheets, etc.

Example 1 526 parts by weight of silica flour, 47.4 parts by weight of quicklime,
Mix 2,000 parts by weight of water, put this into an autoclave with an internal volume of 31 and equipped with a stirrer, heat it after sealing, and perform a hydrothermal reaction for 8 hours while stirring under saturated steam pressure at a temperature and internal pressure of 191° and 0.12 kun/d. did. After the reaction was completed, the reaction product was slowly cooled to normal pressure and taken out from the autoclave. X-ray diffraction analysis revealed that this reaction product was a sheet dry crystal (60aO 681o2
-a2o) was found to be the main crystal. Also. When the product was well dispersed and observed under an electron microscope, a large number of needle-like crystals with a width of about 0.3 to 0.3/7 m and a length of about 1 to 20 lines were observed.

In addition, when observing the slurry as it is without dispersing it under a scanning microscope or under an optical microscope, the diameter is about 25 to 50 μm.
In the surrounding area, spherical secondary particles were observed.

Beaten (beating degree 8R30) cellulose fibers (hereinafter referred to as pulp) or dispersed glass fibers and the above-mentioned sheet dry slurry are uniformly dispersed in water, and this is made into paper using a Tarabee standard machine (100 meshes). After forming, this was pressed at a pressure of 28 kg/d and dried.

The properties of the obtained paper are as shown in Tables 1 to 5.The flammability test method was based on the Mezkel burner method of JI8A1322, and the heating time was 3 minutes, and the char length, afterflame, and residual flame were measured. Dust was measured and pass/fail determined.

Example 2 The sheet dry crystal slurry produced in Example 1, ceramic fibers, rock cool, and glass fibers were uniformly dispersed in water, and this was made into paper using a Tarapee standard machine. 28k
Press at a pressure of li/C-d.

Dry. A 5% solution of alumina sol was sprayed on the surface of M26 paper, and then the paper was pressed at a temperature of 110° C. under a pressure of 28 kg/d. The properties of the obtained paper are as shown in Table 6.

Example 3 85 parts by weight of the solid content of the sheet dried crystal slurry produced in Example 1, 10 parts by weight of beaten pulp, 3 parts by weight of glass fiber, and 2 parts by weight of acrylic resin were uniformly dispersed in water. was made into paper using a Tarabee standard machine, and then it was processed at 28 kl/d.
Pressed under pressure and dried. The properties of the obtained paper are the seventh
Table 7 Example 4 48 parts by weight of quicklime, 52 parts by weight of silica powder and 1200 parts by weight of water were mixed and then placed in an autoclave at 200°C for 15 minutes.
A hydrothermal reaction was carried out with stirring for 5 hours under a saturated water vapor pressure of 1/d. After the reaction is complete, cool slowly and take out the slurry reaction product from the autoclave.

As a result of X1m diffraction analysis, this reaction product was found to be a crystal mainly composed of Sheet dry crystals9.

When this product was well dispersed and observed under an electron microscope, it was found that the width was about 0.03 to 0.5 μm and the length was about 1 to 2 μm.
A large number of needle-like crystals with 0 trends were observed. Furthermore, when the slurry was directly observed under a scanning electron microscope or an optical microscope without being dispersed, it was found that the majority were spherical secondary particles with a diameter of 25 to 100 μm and a gravel-like periphery. After uniformly dispersing polyester-based synthetic IZ pulp or beaten W4 (beating degree 8R30) pulp and the above-mentioned Xonotrite slurry in water and making paper using a Tarabee standard machine (100 mesh), paper was formed. This was pressed at a pressure of 28 cm/d and dried. The properties and preferential orientation of the obtained paper are shown in Table 8.

Note that N1132 and N134 were further subjected to supercalender treatment. The physical properties of the obtained paper were measured in the same manner as in Example 1.

Example 5 In the xonotlite slurry obtained in Example 1, 15 parts by weight of beaten pulp (beating degree 81L30) and 5 parts by weight of alkali-resistant glass fiber were added to 75 parts by weight of xonotrite. Add 5 parts by weight of polyamide epichlorohydrin binder (solid content of 12.5% solution), stir, mix and disperse, and make paper using a Tarabee standard machine (100 meshes).2 B kg/cd.
The properties of the paper obtained were as shown in Table 9.

Example 6 Secondary particles of calcium silicate produced under the same conditions as in Example 1 and having a nine-sheet dry crystal structure were dispersed in water to form a slurry with a concentration of about 3 weight.

Polyester fibrids having a concentration of about 3% by weight were blended into calcium silicate slurry to prepare three types of mixed slurries having a weight ratio of calcium silicate and polyester fibrids of 7:3.6:4.5:5. Each mixed slurry was made into paper using a Fourdrinier paper machine. The speed per second is 50m
The stock concentration on the /min slice is approximately 0.2 wt.
Before slicing, apply a nonionic polymer flocculant (7 Sanyo Chemical,
Sunfloc N-0P) was added at 0.07 weight tS to calcium silicate and polyester fibrids.

Paper making results #101! ! Listed below. Furthermore, Ugly 42 is N13
9 was supercalendered.

Table 10 ◎ Excellent ○ Good × Bad Example 7 Silica powder to o, s parts by weight, raw stone type 74.4 parts by weight,
and 1,100 parts by weight of water were mixed, and the mixture was placed in an autoclave with an internal volume of 31 cm and a stirrer, and after being sealed, the mixture was heated and stirred for 6 hours under saturated steam pressure at a temperature and internal pressure of 191°0,11/C-. A hydrothermal reaction occurred.

After the reaction was completed, the pressure was gradually cooled down to normal pressure, and a sterile reaction product was taken out from the autoclave.

This reaction product is the result of X-ray diffraction analysis.

It was revealed that the slurry was mainly composed of tobermolite.

In addition, when observing the slurry under a scanning electron microscope or an optical microscope, it was found that the slurry had a diameter of about 10 to 1004 m.
Spherical secondary particles were observed.

Next, the above slurry and Bulb (beating degree 5R80°) were uniformly dispersed in water, and this was made into a paper using a Tarapy standard machine (100 meshes), then pressed and dried.

The properties of the obtained paper are shown in Table 11.

Example 8 68.8 parts by weight of silica flour, 81.2 parts by weight of quicklime and 1 too many parts by weight of water were mixed, placed in an autoclave with an internal volume of 81 and equipped with a stirrer, sealed and heated to a temperature and internal pressure of 200°C. , 16Q'/cm" after completion of the hydrothermal reaction for 26 hours with stirring under saturated steam pressure,
After cooling slowly and applying normal pressure, the reaction product in the form of a slurry was taken out from the autoclave.

As a result of X-ray diffraction analysis, this reaction product was found to be a slurry mainly composed of 7 ossiaite.

Further, when the slurry was observed under a scanning electronic microscope or an optical microscope, almost spherical secondary particles with a diameter of about 10 to 60 fim were observed.

Next, the primary slurry and pulp (beating degree 5R800) were uniformly dispersed in water, and this was made into a paper using a Tarabee standard machine (100 mesh), then pressed and dried.

The properties of the obtained paper are shown in Table 12.

Example 9 Silica stone powder 91.01 [Okibe, raw stone jl < 84.0 parts by weight and water 11100 parts by weight were mixed, placed in an autoclave with an internal volume II, sealed and heated until the temperature and internal pressure were 19
After completion of the hydrothermal reaction for 8 hours under a saturated steam pressure of 1'C112KI/Cm'', the reaction product was slowly cooled to normal pressure K and the reaction product in the form of a slurry was taken out from the autoclave.

As a result of xm diffraction analysis, this reaction product was found to be a slurry mainly composed of sheet dry.

Further, when the slurry was observed under a scanning aerial electron microscope or an optical microscope, secondary particles having a diameter of approximately 10 to 8,011 m were observed.

Next, the slurry and pulp (beating degree 5R10') were uniformly dispersed in water, and this was made into a paper using a Tarabee standard machine (1OO mesh), then pressed and dried.

The characteristics of the animals obtained are as shown in Table 18.

l! Example 10 Lime milk prepared to have a sedimentation volume of 48 ml (47 ml as quicklime)
(parts by weight), 68 parts by weight of silica powder, and water to prepare a water-to-solids weight ratio of 24:l, and then charged into an autoclave under saturated steam pressure at a temperature of 200°C and a pressure of 16□cm. The mixture was subjected to a hydrothermal reaction for 4 hours with stirring to obtain a slurry consisting of sheet dried crystals.

Next, the above-mentioned slurry and pulp (beating degree 81110°) were uniformly mixed in water, and this was made into a paper using a Tarabee standard machine, then pressed and dried. Incidentally, the method for measuring Fr, W/ and volume was based on the method described in US Pat. No. 416,291.

The properties of the obtained paper are as shown in Table s14.

Comparative Example: 6% white carbon slurry (810, 71
．． 60F) and 60F calcium hydroxide stery (CaO
After mixing for 1 hour at 26°C under atmospheric pressure, the mixture was charged into an autoclave and subjected to a hydrothermal reaction for 16 hours while stirring under the saturated water vapor pressure of snow at a temperature of 11.40°C and a pressure of 1 h. I forced it.

As a result of X-ray diffraction analysis of the slurry mentioned above, it was determined that it was gyrolite type calcium silicate.
I was lled.

Next, the above slurry and pulp (beating degree 8180°) were evenly mixed in water, and this was mixed in a Tarapee standard machine (
After making the paper using a mesh of 1,100 mesh, it was pressed and dried.

The properties of the obtained paper are shown in Table 15.

Claims (1)

[Claims] ■ (a) A large number of fibers contain secondary particles of calcium silicate selected from the group of wollastonite group, tobermolite group, tricalcium silicate hydrate, and α-dicalcium silicate hydrate. (b) The above-mentioned connected state is such that when the paper is wound with a curvature of 10 mmR, Calcium silicate paper is characterized by its surface not being cracked. ■ An aqueous slurry in which a large number of secondary particles made of calcium silicate selected from the group of wollastonite group, tobermolite group, tricalcium silicate hydrate, and a-dicalcium silicate hydrate are dispersed in water, and fibers. 1. A method for producing calcium silicate paper, which comprises forming a mixture of calcium silicate paper so that the weight of skeleton calcium silicate is 50 or more. (2) The calcium silicate paper according to claim 1, wherein the content of fibrous material is less than 40% by weight. (2) The calcium silicate paper according to claim 1, wherein the content of fibrous material is 30% by weight or less. (2) The calcium silicate paper according to claim 1, wherein the calcium silicate is a wollastonite group calcium silicate. (2) The calcium silicate paper according to claim 1, which further contains other additives uniformly. (2) The manufacturing method according to claim 2, wherein the mixture further contains an additive. (2) The manufacturing method according to claim 7, which comprises impregnating or coating with an additive after the above-mentioned papermaking.