JPS61239100A - Acid resistant ceramic 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 Application Field] The present invention is directed to an #acidic acid fiber which is mainly composed of crystal fibers and partially glass and organic and/or inorganic reinforcing fibers. It is related to Cerami Fukubaber.

[Conventional technology]

Conventionally, acid-resistant vapors have a chemical composition of, for example, s+ol.
ss, o%, CaO14.0%, Mg03.0%, Na
*08.0%, 8gOs6.0%, AIzOs4.0%
Mainly made of C glass fiber and organic reinforcing fiber,
It is composed of a small amount of organic binder if necessary.

These acid-resistant vapors are used as temporary materials such as acid solutions other than hydrofluoric acid and hot phosphoric acid, or as release protection materials for electrode plates of lead-acid batteries.

[Problem that the invention seeks to solve]

C glass fiber, which is the main raw material for glass paper, is generally made by melting it in an electric furnace, drawing it out continuously through a gashing, making it into a continuous filament, and cutting it into a predetermined length. It is 18μ. Although these glass vapor bars have sufficient performance as industrial materials such as puffing materials, sealing materials, and insulation materials, and construction materials such as M-fining materials and wall materials, they are not suitable for the main use of acid-resistant vapor. As a filter material and a material for separating and protecting electrode plates of lead-acid batteries, the fiber diameter is large, so there are problems with the vapor porosity and the size of the voids, and the performance is not fully satisfactory.

Recently, ultrafine C glass fibers with a fiber diameter of 097 to 2μ have been developed, and their performance as acid-resistant vapor filters or electrode plate isolation and protection materials for lead-acid batteries has been significantly improved. However, ultra-fine C-glass fibers are made by blowing flame onto a glass loft that has been melted to create fibers, or by blowing molten glass little by little from a high-speed rotating body to create fibers, which reduces energy consumption and productivity. This makes it an expensive material.

On the other hand, alumina-silica ceramic fibers are ultrafine glass fibers with a fiber diameter of 1.5 to 2.5 μm that are produced in large quantities.

Alumina-silica ceramic fiber is made of high-purity alumina and silica [! It is made by melting it in a furnace and blowing the high-temperature molten mass into fibers using a high-speed stream of steam or air or the centrifugal force of a high-speed rotating rotor.It is a cheaper material than the ultra-fine C glass fiber mentioned above. be. However, alumina-silica ceramic fiber has a chemical composition of Ah (h46-48%, 5ift 52-5
8% or A110156~57%, 5iO148~
Because it is a glassy fiber with a carbon fiber content of 44%, its acidity is inferior to that of the above-mentioned C glass fiber, making it unsuitable as a raw material for acid-resistant vapor used as a filtration material for acid solutions or as an isolation and protection material for electrode plates in lead-acid batteries. there were.

[Means for solving the problem and its effect] The present invention is m
Alumina-silica ceramic fibers, which are ultra-fine glassy fibers with a fiber diameter of 1.5 to 15 μm, are heat-treated to transform them into glass fibers that mainly contain mullite crystals, cristopalite crystals, and a small amount of silica. Acid-resistant reinforcing fibers such as C-glass fibers, silica fibers, polyethylene fibers, acrylic fibers, polypropylene fibers, and vinylidene fibers are added to the fibers and a small amount of organic binder as necessary. This relates to a 1+11# ceramic vapor made up of:

The present invention will be explained in detail below.

Alumina-silica ceramic fiber is a glass fiber made of alumina and silica, and its chemical composition is, for example, AhOt 47.8%, 5ift 51.9%, F
oxes 0.06%, Nut OO, 24%, Cao
OoOl%, TiChO, 02%. Further, the form of the fibers is, for example, a collection of fibers with a fiber diameter in the range of 1 to several microns, an average diameter of 2.0 microns, and a fiber length of 250 microns or less. The structure of the fiber is schematically shown in FIG. 1, which will be listed later. Aluminum ions (
A i a + >, one of which has 8 oxygen ions (0
-), and because it does not form a network structure like silica, it is in a very unstable state and easily dissolves when it comes in contact with acid. .

In the present invention, alumina-silica ceramic fibers are treated with t-coating to produce fibers made of glass mainly composed of mullite crystals, cristopalite crystals, and silica, thereby preventing acid elution of aluminum ions constituting the fibers. Ta. In other words, the structure of the heat-treated fiber is schematically shown in Figure 2, which will be listed later, and the structurally unstable aluminum ions transform into stable mullite crystals (8A1Os/2SiOt) through heat treatment. This dramatically reduces acid elution.

When alumina-silica ceramic fiber is heated, mullite crystals precipitate around 900-1100°C.
The amount of precipitation increases rapidly around 1100-1250°C, and cristobafite crystals are precipitated in addition to mullite crystals around 12100-1400°C.

In the present invention, an alumina-silica ceramic fiber is heat-treated within a temperature range of 950 to 1400"C to produce a fiber consisting of 20 to 70% by weight of mullite crystals and the balance being cristopalite crystals and glass mainly composed of 7 liqu. If the temperature of the ripening treatment is less than 950°C, the amount of pallite crystals precipitated in the fiber is small;
Due to the presence of a large amount of structurally unstable aluminum ions, elution with acids such as sulfuric acid occurs;
If the temperature exceeds 0'Ot-, the cristoparite crystals of the mufit crystal alium precipitated in the fibers will become coarser, making it impossible to maintain the fiber form.

The fiber produced as described above, which is composed of glass with 20 to 70% by weight of mullite crystals and the balance consisting mainly of cristobafite crystals and silica, has low mechanical strength and cannot be used with pulpers, beaters, or Probev type stirring. Disperse it uniformly in water using S, etc. to make a slurry, and use it in a round netting machine,
When producing vapor by paper-making using a fourdrinier machine or the like, the fibers may break and become short, and the vapor made of single fibers has a problem in that it does not have sufficient mechanical strength.

In the present invention, 20 to 70% by weight of mullite crystals, 50 to 95% by weight of fibers consisting of glass mainly consisting of cristopalite crystals and silica, and 5 to 50% by weight of reinforcing fibers consisting of acid-resistant inorganic or organic fibers. The mechanical strength of the vapor was improved by adding 10% by weight or less of an organic binder as necessary.

Suitable organic acid-resistant reinforcing fibers are polyethylene fibers, acrylic fibers, polypropylene fibers, or vinylidene fibers. These organic fibers have a fiber diameter of, for example, 5 to 20 microns.

Examples of organic binders include vinyl acetate resin, acrylic resin,
Examples include pheno resin, PVC resin, PVA, gelatin, and starch.

If the composition ratio of fibers consisting of 20 to 70% by weight of mullite crystals and the balance being cristobafite crystals and glass mainly composed of silica is less than 50% by weight, the acid resistance of the vapor will not be sufficient and there will be a problem that the cost will increase. If it exceeds 96% by weight, the mechanical strength of the vapor will not be sufficient.

If the composition ratio of reinforcing fibers made of acid-resistant inorganic or organic fibers is less than 5% by weight, the mechanical strength of the vapor will not be sufficient, and if it exceeds 50% by weight, there will be a problem that the cost will increase.

In addition, for applications other than filtration materials and electrode plate isolation and protection materials for lead-acid batteries, where the strength of the vapor is more important than the porosity of the vapor or the size of the pores, an organic binder of 10% by weight or less is added. You can also do that.

[Examples and comparative examples]

Examples of the present invention will be shown below along with comparative examples.

Chemical composition: At snow 0147.8%, Stow 51.9
96, Flllxes O, 06%, Nato 0.2
4%, Ca0O,01'fJ, T i Of O,02
%, and the fiber diameter is 10μ as the average diameter.
Silica-based ceramic fiber was heated to 95G with an electric torch.
Heat treatment was performed at a temperature range of 1400°C for a predetermined time. Table 1 shows the mineral composition of the fibers obtained by the heat treatment described above.

Table 1 also shows that the fibers obtained by the above heat treatment were heated to 80°C.
The fibers were immersed in sulfuric acid with a C1 specific gravity of 1.2 for 5 hours, and the percentage of acid elution was expressed as the weight loss of the fiber at that time, and the results are shown in Table 2.

Table 2: Fibers obtained by the heat treatment described above, C gaff fibers, Nlica fibers, polyethylene fibers, acrylic fibers,
l1i1 made of polypropylene fiber and vinylidene fiber
A solid content concentration of 061% with a predetermined blending ratio of acidic reinforcing fibers.
Add to water so that
．． 0-L OtR vapor was made into paper and dried. Table 8 shows the acid elution percentage, which indicates the acid resistance, and the porosity, which is an important quality for the isolation and protection material of the electrode plates of lead-acid batteries, of the vapor obtained from the above-mentioned paper making process.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to obtain a paper with excellent acid resistance that is made mainly of fibers at a very low cost.
It is extremely useful as a filter material for acid solutions and as a material for isolating and protecting electrode plates of lead-acid batteries.

Claims (1)

[Scope of Claims] 1. 50 to 95% by weight of fibers consisting of 20 to 70% by weight of mullite crystals, the balance being cristopalite crystals and glass mainly composed of silica, C glass fibers, silica fibers,
An acid-resistant ceramic paper comprising 5 to 50% by weight of one or more of acrylic fibers, polypropylene fibers, and vinylidene fibers and, if necessary, 10% by weight or less of an organic binder. 2. The fiber made of 20 to 70% by weight of mullite crystals and the balance of cristopalite crystals and glass mainly composed of silica is obtained by heat-treating alumina-siliceous ceramic fibers at a temperature range of 950°C to 1400°C. Acid-resistant ceramic paper according to claim 1.