JPH0337147A - Cement paper - Google Patents

Abstract

PURPOSE:To obtain a cement paper having improved strength and self- extinguishing property in hydrated and cured state by forming a paper sheet from a mixed slurry containing hydraulic cement, pulp and Al(OH)3. CONSTITUTION:A green sheet is produced by conventional paper-making process from a mixed slurry containing 100 pts.wt. of hydraulic cement, <=400 pts.wt. of aggregate having average particle size of finer than 100 mesh (e.g. chamotte powder), 5-150 pts.wt. of pulp, 20-200 pts.wt. of Al(OH)3 and, as necessary, an organic binder (e.g. PVA), a sizing agent, a paper-strengthening agent, a filler, a fixing and coagulating agent, a reinforcing fiber (e.g. glass fiber), etc. The green sheet is dehydrated by pressing under a specific pressure and dried to obtain the objective cement paper.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to cement paper obtained by paper-making a mixed slurry containing hydraulic cement and pulp.

(Prior art) For example, a honeycomb core lO having the shape as shown in FIG. The honeycomb sandwich structure to which 12 is attached is lightweight (because the space area is extremely large), has high strength and rigidity for ff1ffi, and has heat insulation and sound insulation properties, so it is suitable for aircraft, It is widely used as a structural member in various fields such as vehicles and architecture.

There are many types of honeycomb cores, including metal cores made of aluminum or stainless steel, plastic cores, FRP cores, paper cores, etc. Among these, paper cores require less material and processing costs. Although it is useful from a viewpoint, it has drawbacks such as: (1) it is easily flammable because it is made of paper, (2) it has low strength, and (0) it has poor adhesion to the surface material.

Therefore, the present applicant filed an earlier patent application (Japanese Patent Application No. 61-2478).
No. 75) proposed cement paper that could be used as a constituent material for such honeycomb cores, and also filed a patent application No. 61-2
In No. 53357, we proposed a honeycomb body made from cement paper.

The specific content is that a mixed slurry made by adding 5 parts by weight or more of pulp to 100 parts of hydraulic cement is processed to form a green sheet (which is then dehydrated and dried to produce cement paper). The main idea is to obtain or bend this, combine it with a sheet of cement paper, and bond the contact points with a cement-based adhesive to form a honeycomb body.

In the case of this cement paper and honeycomb body, it hardens and increases its strength by hydration curing, which is a feature not found in other materials. It was found that the strength and self-extinguishing properties were still insufficient, and there was room for a rating of 4 good.

(!!Means for solving the problem) The present invention was made to solve the above problem, and the gist thereof is to add 5 parts by weight or more of pulp to 100 parts by weight of hydraulic cement. Contains aluminum hydroxide powder in a ratio of 20 to 100 parts by weight of cement.
The purpose is to obtain cement paper by making paper from a mixed slurry containing 200 parts by weight.

That is, the present invention is characterized in that aluminum hydroxide powder is contained in a mixed slurry of cement and pulp that is to be used as a papermaking material for cement paper.

The present invention has been made based on the following findings.

Conventionally, aluminum hydroxide paper obtained by paper-making a mixed slurry of cellulose fibers and aluminum hydroxide powder has been known as noncombustible paper. The non-combustible mechanism is thought to be as follows.

Aluminum hydroxide has the chemical formula Al(OH)3 or Al
As expressed by 2O3.3H20, it contains 3 moles of water of crystallization in the molecule, and when heated to about 300°C
It emits crystal water at the front and back, absorbing heat from its surroundings. This temperature of around 300° C. is the temperature just before a flame starts, and therefore, paper whose main component is aluminum hydroxide is said to be prevented from rising in temperature and will not burn.

The present inventor focused on such aluminum hydroxide paper,
The idea was to incorporate aluminum hydroxide powder, which is a constituent material, into cement paper.

Through various experiments, it was confirmed that the inclusion of such aluminum hydroxide powder did indeed improve the flame resistance, but at the same time, the resulting cement paper was cured and hardened by hydration. We confirmed the fact that the intensity of time is increasing.

The specific reason for this has not yet been confirmed, but 1
It is assumed that this is due to the following reasons.

The microstructure of cement paper obtained by making paper from a slurry containing cement powder, aggregate, pulp, etc. is as shown in Figure 2 (A) because the particle size of cement powder, etc. is relatively large. It is thought that the structure has many gaps 16 between particles 14 (cement, aggregate, etc.).

On the other hand, when aluminum hydroxide powder is added/contained, as shown in (B), the powder particles 18 of aluminum hydroxide powder are cement particles or aggregate particles (when aggregate is included). , that is, the gap 1 between the cement raw material particles 14
6 and increases the packing density of the cement paper, and this increase in density is thought to lead to strengthening of the hydration bond of the cement components when the cement paper is hydrated and cured.

In addition, this aluminum hydroxide powder is monoclinic and has a flat plate or spherical particle shape. Therefore, when a raw paper sheet is compressed, slipping of cement particles, etc. is promoted, and each particle is filled. It is inferred that the increase in the ratio and compaction density is also advantageous in improving the strength of the cement paper after Kiwa curing.

As mentioned above, one aspect of the present invention is to obtain cement paper by papermaking from a mixed slurry containing hydraulic cement, pulp, and aluminum hydroxide powder. In addition to these essential components, the mixed slurry can of course contain reinforcing materials such as aggregates and glass fibers, organic binders, papermaking aids, and the like.

Cement here includes portland cement, alumina cement, ply ash cement, blast furnace cement,
Silica cement and mixtures thereof and other cement materials can be used.

In addition, as aggregate, chamotte powder, which is an artificial firewood,
Scherchen powder, andesite powder, which is a natural product, basalt powder,
Igneous rock powder such as silica sand or other materials may be used. However, such aggregates preferably have an average particle diameter of 100 mesh or less.

The amount of aggregate added is preferably 400 parts by weight or less per 100 parts by weight of cement.

Next, when it comes to pulp, there are synthetic pulp and synthetic fibers.

Chemical 1m blind, natural pulp (Susha pulp, hemp pulp, etc.), MFC (microneugrill cellulose), etc. may be used as necessary. The amount of this pulp added must be 5 parts by weight or more relative to the lOffiit part of cement for paper making, and is preferably in the range of 10 to 150 parts by weight. This is because if the amount is less than 10 parts by weight, continuous papermaking becomes difficult, and if it exceeds 150 parts by weight, the flame resistance deteriorates.

The binder is used to bind each particle and material, such as PVA, vinyl acetate, etc.

SBR, ethylene-vinyl acetate copolymer.

Acrylic, I! ! Vinyl chloride, vinylidene chloride, etc. can be used.

On the other hand, as papermaking aids, for example, sizing agents, 7 paper strength enhancers, phyte, fixing/flocculants, 9 dispersants, etc. can be blended, and glass Iam, rock, etc. can be added for reinforcement to the extent that they do not interfere with papermaking. wool, ceramic fiber,
It is also possible to blend inorganic fibers such as asbestos, metal fibers, cardiac fibers, and mixtures thereof.

As mentioned above, the content of the present invention is to add aluminum hydroxide powder as a characteristic component. The addition amount range is 20 to 2 to 1 part of cement zooi1+.
It needs to be in the range of 00ii parts. The reason for this is that if the amount of aluminum hydroxide powder is less than 20%, the self-extinguishing properties of the resulting cement paper will be insufficient.
Moreover, if the force exceeds 200 parts, the bending strength will be insufficient. In addition, when using such aluminum hydroxide powder, it is recommended to add it so as to replace it on the side of the bone. Aluminum hydroxide powder should not be added to replace aggregate.

Unreleased LjJ cement paper can be produced, for example, as follows.

That is, a mixed slurry containing the above-mentioned components is prepared and subjected to a paper-forming process according to a conventional method, and the obtained paper product, that is, a green sheet, is dehydrated and pressed at a predetermined pressure, and then dried. This yields dry cement paper, which is then bonded to an upper sheet of cement paper that has been bent into a predetermined shape to obtain the honeycomb body. This cement paper and honeycomb body hardens and develops great strength when hydrated and cured.

(Example) Next, in order to more clearly demonstrate the features of the present invention, examples thereof will be described in detail below.

Shudori Portland cement was used as the cement, fine silica sand (200 mesh or less) was used as the aggregate, and Showa Light Metal Co., Ltd.'s Hijirai) H-42 was used as the aluminum hydroxide powder.
(average particle size 1 pm), general papermaking pulp (NBKP) was used as the pulp, and vinylidene chloride (NBKP) was used as the binder.
Asahi Kasei Co., Ltd.'s Saran Latex
801CJllJlli 3 jm) Wojin It JT
Mix in various proportions shown in Table 1,
The mixed slurry was processed into paper according to a conventional method, and then dehydrated and
It was compressed to obtain a green cement sheet. This green cement sheet was compressed by roll pressing at a linear pressure of 200 kgf/c++s, and the density of the compressed body was measured. Further, the obtained cement paper was steam-strengthened (4 days at a temperature of 60° C. and a relative humidity of 100%), and its flexural strength, flexural modulus, and self-extinguishing property were measured. The bending strength and bending elastic modulus are for a thickness of 0.5 mm.
, are measured values for a strip-shaped sample with a width of 15 mm,
Also, it is self-extinguishing.

Evaluation was made by applying a flame for 5 seconds and observing the burnt layer after removing the flame. At that time, the fire should be extinguished immediately after removing the flame. ○ indicates that the fire spread for several seconds without raising a flame and self-extinguished, W1< Δ indicates that the fire spread and self-extinguished
The results are shown in Table 1, with those that caught fire and burned being marked as x.

(The following is a blank space) From the results in Table 1, it can be seen that by adding aluminum hydroxide powder, and as the amount added increases, the bending strength and bending elastic modulus increase, and the self-extinguishing property also improves.

(Effects of the Invention) As described above, the cement paper of the present invention can be bent and bonded, has self-extinguishing properties based on the content of aluminum hydroxide powder, and is hardened by hydration curing.
It has the advantage of being sufficiently strong after being cured.

The cement paper of the present invention can be used as a substitute for conventional noncombustible paper such as aluminum hydroxide paper, and can also be used as a base paper for interior and exterior wallpaper building materials, honeycomb core material, etc. The tiered poles and expanded honeycombs are
Whether cured or uncured, it can be applied to core materials for building materials, buffer materials, etc.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a perspective view showing an example of a honeycomb core as a use of cement paper according to the present invention, and FIG. 2 is a perspective view of aluminum hydroxide powder as a component of the cement paper of the present invention. FIG. Figure Figure CA) (B) 1m

Claims (1)

[Claims] Paper is made from a mixed slurry containing pulp in a ratio of 5 parts by weight or more to 100 parts by weight of hydraulic cement, and aluminum hydroxide powder in a range of 20 to 200 parts by weight to 100 parts by weight of cement. Cement paper characterized by: