JPS6235841A - Multilayer paper - 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] [Industrial Field of Application] The present invention provides a paper that does not impair the excellent features of conventional inorganic paper.
This paper relates to multilayer paper with high paper strength that cannot be obtained with conventional inorganic paper.

[Conventional technology]

Conventional inorganic paper is made by dispersing inorganic fibers and inorganic fillers in water and adding organic and inorganic binders as necessary to make the raw material for papermaking, that is, papermaking slurry. Paper is made by adding an inorganic flocculant to make fine fibers and inorganic fillers into a floc, and then making paper using a paper machine such as a round net or fourdrinier. In addition, inorganic fibers are defibrated using a special dry defibration machine such as an opener, and the defibrated fibers are accumulated on a net conveyor by means such as air Q-feeding, and if necessary, rootless or organic fillers or bonding materials are used. Non-n paper made into sheets by adding agents is known.

[Problem that the invention seeks to solve]

The inorganic paper made as described above not only has excellent cushioning properties, sealing properties, and electrical insulation properties in a wide range of temperatures from room temperature to high humidity, but also has excellent heat insulation properties, fire resistance, chemical resistance, corrosion resistance, and dimensions. It has many excellent features such as stability. However, these functions can only be obtained when the organic content of the organic binder, T8'U flocculant, etc. in the inorganic paper is less than a few percent, but even a few percent of the organic content can be fatal. There are some defects. For example, organic matter in inorganic paper, which has high lvlability at room temperature, is carbonized when exposed to high temperature and relatively low oxygen conditions, and this carbon becomes a good conductor of electricity, which is a characteristic of inorganic paper. Insulation is lost. For these reasons, it is preferable to reduce the organic content in the inorganic paper as much as possible, but there is a problem in that when the organic content is reduced, the mechanical strength, that is, the paper strength of the inorganic paper decreases. In particular, wire-covering paper and insulating paper inside transformers are wrapped by machines under strong tension and with a small radius of curvature during the manufacturing of wires and transformers. Important quality items include flexibility, that is, no cracking during bending. On the other hand, inorganic paper, which has excellent high-temperature electrical insulation by reducing organic content such as organic binders and flocculants, does not satisfy the image quality in terms of tensile strength and folding strength as shown in Table 1. In the field of electrical insulation materials, heat-resistant electrical insulation paper with excellent mechanical strength has been desired.

Table 1 Inorganic binder is colloidal silica Dielectric strength Tensile strength according to J1802111 JI8 P 81111 Evening resistance Fr strong [J
IE! F 8112.8902 p resistance 4tiJH
O148# It is also an interior material in the field of building materials that utilizes decorative functions. In recent years, quality characteristics such as fire resistance, heat resistance, and smoke resistance have been required for wallpaper and fusuma paper.Although it has been replaced with inorganic paper, the basic combustible property of the organic content cannot be eliminated, and furthermore, the organic content in inorganic paper makes paper Conventional inorganic paper, which is joined from the front side to the back side, has the disadvantage that in the event of a fire, the fire can pass from the front side to the back side of the paper. Furthermore, since the inorganic fibers constituting inorganic paper basically have poor water absorbency, it has been difficult to print on quality-free paper for decorative purposes. In addition to the quality problems associated with these inorganic papers, there are also the following problems in manufacturing, and it has been desired to solve them.

Paper manufacturing is roughly divided into the part that pre-processes paper raw materials and the paper making part.
The papermaking section is further divided into a papermaking section, a dewatering press section, a drying section, and a winding section. The paper layer made in this paper making section is conveyed in a wet state halfway to the drying section. Therefore, wet strength of the paper layer is required during paper manufacturing. General organic paper is mainly composed of valves, and when the valves are beaten, the fibers branch out (
(fibrillation) and become intertwined during paper making, providing strong tensile strength even in the wet state. But what about the inorganic g that makes up inorganic paper? Unlike bulbs, 4-fiber paper not only has poor branching but also has a smooth surface, so inorganic paper has a low wet tensile strength and cannot be made at a high paper-making speed. In general, the paper making speed of inorganic paper is less than 10m/m, which is much slower than the paper making speed of several hundred m/m for organic paper. There was a problem that the cost was high.

[Means for solving problems]

The present invention is aimed at solving the above-mentioned problems, and one or more of the ceramic fibers, inorganic filler, and inorganic binder have a resistance of 80W or more, and if necessary, a small amount of The present invention provides a multilayer paper made by laminating a plurality of inorganic papers made of an organic binder and other forming aids and organic papers made mainly of organic fibers.

More specifically, an inorganic layer (■) and an organic layer (■) as shown in FIG. 1 which combine the characteristics of an inorganic material such as fire resistance and heat resistance due to an inorganic material with an organic content of 2Qwt% or less and the high tensile strength of an organic layer (2) U It is a multi-layer paper made up of one to three layers, or several layers stacked on top of each other.

The multilayer paper of the present invention will be explained in detail below.

Ceramic fibers that make up inorganic paper include asbestos, glass fiber, rock wool, alumina/silica fiber, potassium titanate fiber, silica fiber, alumina crystalline fiber, mullite crystalline gIia, zirconia fiber, etc. In particular, alumina-silica fibers are preferred from the viewpoint of fire resistance and cost.

Inorganic fillers include mica, kaolin, talc, calcium carbonate, clay, etc., and mica is particularly preferred from the standpoint of insulation.

Inorganic binders include clay, silica sol, alumina sol, water glass, etc. Of these, especially 1fft of clay minerals!
Sepiolite is preferred because it has flexibility and high bonding strength.

The total amount of inorganic components consisting of one or more of ceramic fibers, inorganic fillers, and inorganic binders is 80 wt% or more in the inorganic paper, and molding aids, etc. The total amount of organic components is 20 wt% or less.

If the total amount of the inorganic components is less than 3Qwt% and the total amount of organic components such as forming aids exceeds 2Qwt%, the paper strength such as tensile strength of the inorganic paper will improve, but on the contrary, the heat resistance and fire resistance will improve. , since the performance as an inorganic material such as electrical insulation is not fully satisfied, the total amount of the inorganic component is 8Qv.
It is necessary that it is t% or more.

In particular, when the multilayer paper of the present invention is used as a high-temperature fireproof insulating paper, it is preferable that the total amount of the inorganic components is 98% by weight or more.

O-free paper has a total content of organic components of inorganic components of 20%.
If it is less than Wt%, organic materials such as latex, vinyl acetate, PVA, resins such as acrylamide, natural valves, synthetic pulp, etc. A f&, starch, methyl cellulose,
An organic binder such as a sizing agent such as carboxyl group methylcellulose and a polymer flocculant can be contained. Further, part or all of the polymer flocculant can be replaced with an inorganic flocculant such as aluminum sulfate or polyaluminum chloride.

The organic fibers constituting the organic paper include natural fibers such as softwood and hardwood, polyethylene fibers, acrylic natural fibers, etc., but natural fibers and synthetic pulp are particularly preferred in terms of paper strength and cost. Further, it is preferable that the ratio of the organic fiber to the organic paper is 7Qwt% or more. In addition to organic fibers, organic paper may contain small amounts of inorganic fillers such as kaolin, talc, clay, and calcium carbonate, as well as organic binders and polymer flocculants such as latex, acrylamide, starch, and PVA. can.

The multilayer paper of the present invention has a plurality of inorganic papers and organic papers configured as described above bonded together using an inorganic or organic binder.
The binder that adheres to the laminated inorganic paper and organic paper is an inorganic binder such as clay, silica sol, alumina sol, or water glass, or an organic fiber such as latex, vinyl acetate, resin such as PVA acrylamide, natural valve, or synthetic pulp. , starch, methyl cellulose, sizing agents such as carboxyl group methyl cellulose, and other organic binders.

The binder is applied secondarily to the adhesive surface of the inorganic paper and organic paper, or the binder contained in the inorganic or organic paper is transferred by combining the wet inorganic paper and organic paper after paper making. This is what I did.

Moreover, the multilayer paper of the present invention is a combination of inorganic paper and organic paper, but in particular, it is a two-layer paper consisting of an inorganic layer (■) and an organic layer (■) as illustrated in FIGS. 1 to 3. The structure is preferable for purposes where fire resistance is important, and the 8-layer structure has an inorganic layer in the center and an organic layer on both sides, with decorative printing on the front and adhesive on the back. A three-layer structure having an organic layer (1) in the center and an inorganic layer (2) on both sides is preferable for wallpaper to be attached, and has strong fire resistance and insulation performance (preferable for the intended purpose of use). Multilayer paper has one or two inorganic layers constituting the multilayer paper based on the total weight of the multilayer paper (expressed in basis weight, where the total weight of 9 or more is the weight per unit area of paper, 5 or more layers wt%) It is preferable that If the total weight of the inorganic layers relative to the entire multilayer paper is less than 5 wt%, the fire resistance performance, which is one of the important properties of inorganic paper, will not be sufficiently exhibited. Therefore, a preferable range is 50% or more.

Next, FIG. 4 explains the papermaking equipment used to manufacture the multilayer paper of the present invention. In Fig. 4, ■■■ is a device for defibrating inorganic fibers and organic fibers, dispersing them in water, and adding fillers, binders, and other forming aids to produce papermaking raw material slurry.

■■■ is a circular paper machine that makes paper from the paper constituent materials dispersed in the slurry, and should be used depending on the structure of the multilayer paper being manufactured. For example, the two-layer paper foil in Figure 1, ■, ■, ■, ■
By combining the round nets and ■, one of them has no 131 (η
, the other one can perform organic layer papermaking. Figure 2,
Figure 3 is also constructed based on the same idea. (zl is the second
In the figure, the inorganic layer is made using ■ and the organic layer is made using ■■. In addition, in Fig. 3, 81 layers are made with organic layer (■) and no organic layer (2) with ■■. (2) is a felt for transferring the paper layers cut from the round nets and overlapping the paper layers cut from each round net. 0
is a device for dehydrating water in paper Mj. (2) is a press device for increasing the adhesion of the paper layers that have been made together. σbO is a cylinder dryer device for drying the paper layer. ■ is a device for winding up paper.

Examples First, the composition and physical properties of each sheet of paper constituting the multilayer paper of the present invention will be explained.

Tables 2 and 8 show the compositions of the inorganic layers constituting the multilayer paper of the present invention.

Table 2 Values are N&% Table 3 Table 4 shows the composition of the organic layer constituting the paper of the present invention.

Table 4 Tables 5 to 7 show physical property values for examples of each single sheet of organic paper and inorganic paper constituting the multilayer paper of the present invention.

Table 5 Table 6 Table 7 Table Sample The multilayer paper of the present invention as shown in Table 8 was obtained by combining each single paper having a sample thickness of O and a fin thickness of 280 g/mH to J. The same evaluation test as in Table 1 was conducted on this multi-a paper.

Table 8 As can be seen from Table 8, the multilayer paper of the present invention has high paper strength and excellent electrical properties at high temperatures, so it can be used as insulating paper for covering electric wires that require fire and heat resistance, and as insulation for transformers that require fire and heat resistance. It can be used for paper. Furthermore, since it has a completely non-combustible layer and excellent printing properties, it can be used for wallpaper in the architectural field, where flame retardancy and fire resistance are required in recent years.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional perspective view of a two-layer structure of the multilayer paper of the present invention. FIGS. 2 and 3 are perspective views of a three-layer structure of the multilayer paper of the present invention. FIG. FIG. 3 is a cross-sectional view of the device to be manufactured. ■Inorganic layer, ■Organic layer, ■■■: Pulper, ■■■:
Circular paper machine, ■: Felt, ■: Suction box for dehydration, ■: Roller press, OO;
Cylinder dryer, ■: Winder.

Claims (1)

[Claims] 1. Contains 80% by weight or more of ceramic fibers and one or more of an inorganic filler and an inorganic binder, and if necessary, a small amount of an organic binder and/or a molding agent. A multilayer paper made by laminating multiple sheets of inorganic paper containing an auxiliary agent and organic paper containing mainly organic fibers. 2. At least 1 each of the inorganic paper and the organic paper
A multilayer paper according to claim 1, comprising each layer. 3. The multilayer paper according to claim 1, comprising one layer of inorganic paper and one layer of organic paper formed on each side of the inorganic paper. 4. The multilayer paper according to claim 1, comprising one layer of organic paper and one layer of inorganic paper on each side of the organic paper. 5. The ceramic fiber is one or more selected from alumina-silica fiber, alumina crystalline fiber, mullite crystalline fiber, zirconia crystalline fiber, potassium titanate fiber, and silica fiber. Multilayer paper according to claims 1 to 5. 6. Claims 1 to 5, wherein the total basis weight of one or more layers of inorganic paper is 50% by weight or more of the whole basis weight
Multilayer paper as described in section.