JPS62191599A - Production of inorganic 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] This invention relates to a method for producing inorganic paper that is effective as a reinforcing material for composite plastics. The most commonly used paper is paper made from nine particulate inorganic compounds, that is, fillers, or from various pulps.

Furthermore, various inorganic fiber compounds typified by glass fiber are known as reinforcing materials.

Various reinforcing materials are selected and used depending on the required performance and cost of composite plastics.

The molding material for composite plastics containing the above-mentioned inorganic compounds has various forms such as powder, pellet, and sheet, but in order to obtain a &layer molded product, a sheet is required.

What are the characteristics of sheet-form molding materials?

It has the advantage of being able to easily mold thick-walled molded products, large-sized molded products, thin-walled molded products, and complex shapes. Conventionally,
As a sheet-shaped inorganic reinforcing material.

There are many woven fabrics such as glass fibers and carbon fibers, and non-woven fabrics made by uniformly dispersing short fibers and bonding the fibers with a binder.
Used as a reinforcing material for composite plastics.

These reinforcing materials are usually made by impregnating them with a liquid resin or a resin solution dissolved in a solvent.

It is dried and semi-cured and then molded into sheet la.

The characteristics of a molded product depend on the ratio of the resin and reinforcing material used, and the higher the ratio of reinforcing material (I see).

Approaching the inherent properties of reinforcing materials (.

However, there is a limit to the filling rate of the reinforcing material, which is approximately 52% by volume when randomly distributed.

When the reinforcing material is aligned in one direction, it is calculated to be about 82% by volume, but in reality, it is difficult to manufacture collated plastics filled with reinforcing material up to the calculated value.

As previously shown in Japanese Patent Application Laid-Open No. 60-81399,
Inorganic paper was manufactured by using organic fibers, which are microfibrillated inorganic fibers, as a binder.

[Problem that the invention seeks to solve]

In order to manufacture high-performance composite plastics with close to the maximum filling rate (calculated value), the form of the reinforcing material must have a large weight latitude. In the case of the conventional nonwoven fabrics mentioned above, short fibers of several millimeters to several centimeters are randomly overlapped and bonded by a binder, so if the length of the short fibers is long, it is difficult to produce a nonwoven fabric with low porosity. . Furthermore, since the distribution of the short fibers becomes non-uniform, there are drawbacks such as variations in the properties of the composite plastic.

Although it is possible to reduce the porosity of a nonwoven fabric by shortening the fiber length of short fibers, it is necessary to increase the bonding force between the fibers, and a large amount of binder is required. An increase in the amount of binder is undesirable because it leads to a decrease in the durability of the composite plastic. That is, the conventional paper had a problem in that it was difficult to control the porosity and impregnability of the paper, resulting in wide variations in quality.

This invention was made to solve these problems, and has a suitable porosity and excellent impregnability.

The object of the present invention is to obtain a method for producing an inorganic paper formed using as little binder as the conventional method.

[Means for solving problems]

In the method for producing inorganic paper of this invention, the fiber diameter is 100 μm.
m or less and the fiber length is in the range of 2 to 500 times the fiber diameter to a desired fiber length distribution. This process involves mixing and dispersing organic fibers fibrillated to a diameter of 10 μm or less to form paper.

[Effect]

Due to the WM adjustment of the fiber length distribution in this invention, the filling amount can be increased to close to the calculated value by appropriately combining long and short fiber lengths, and the quality is uniform and even better impregnating properties can be achieved. It is possible to maintain the porosity and reduce the porosity.

〔Example〕

Inorganic fibers according to an embodiment of the present invention include:

For example, continuous fibers such as glass fibers, carbon fibers, silicon carbide fibers, boron fibers, alumina fibers, alumina silicate fibers, quartz fibers, zirconia fibers, asbestos fibers, or short fibers, as well as magnesia, alumina, boron carbide, and silicon carbide.

Whiskers such as silicon canide, potassium titanate, and graphite can be used. As a method for imparting fiber length distribution to these fibrous inorganic compounds, when the above-mentioned inorganic compounds are continuous fibers, each short fiber cut into a predetermined length with a fiber length ranging from 50 mm to several microns is used. Prepare.

There is a method of mixing short fibers having different fiber lengths at a predetermined ratio.

When making dense paper, the number of short fibers with a fiber length of 1 mm or less is increased; however, if the amount is too large, the impregnating property of the resin will decrease, so this ratio must be adjusted depending on the density and porosity of the paper to be obtained. Must be. In addition, as a method to give fiber length distribution to inorganic short fibers of several millimeters in length, 9. Put a predetermined amount of inorganic short fibers into a mixer that applies intense shearing force, and take out the inorganic short fibers after applying shearing force for a certain period of time. This is to provide fiber length distribution.

In the case of inorganic fibers, the fibers break more easily than organic fibers, so if the time for applying shearing force is controlled, a suitable fiber length distribution can be achieved. In addition, as a similar method, a fiber length distribution can be obtained by dispersing a predetermined amount of the above-mentioned inorganic short fibers in water and mixing the fibers with a constant speed rotary machine equipped with rotary blades that apply shearing force. can be set. In this case, the fiber length distribution is determined by adjusting the rotational speed, adjusting the time w4 for applying the rotational force, and adjusting the fiber m concentration. Furthermore, if it is necessary to mix fibers with very short fiber lengths, one method is to add the entire appropriate amount of the above whiskers to the fibers that have been given a fiber length distribution by the above method.

Note that the fiber diameter of the inorganic fibers must be 100 μm or less, and the fiber length must be 2 to 500 times the fiber diameter. 100
If it is larger than μm, the inorganic paper will lack flexibility, if it is less than 2 times the reinforcing property of the inorganic paper will be lost, and if it is more than 500 times the fibers will become entangled and cannot be uniformly dispersed. For example, single fibers of natural fibers such as cotton, flax, wool, and silk that have been defibrated to a fiber diameter of several microns or less after removing impurities, or cellulose made from wood and viscosleek which is a cellulose rust conductor. Fibers made by fibrillating or acetate fibers to a size of 10 microns or less are used.Furthermore, polyamide fibers, polyvinyl alcohol fibers, polyvinylidene chloride fibers,
Polyvinyl chloride fiber, polyacrylonitrile fiber,
Polyester fiber, polyethylene fiber, polypropylene fiber, polyurethane fiber.

After stretching polycyanide vinylidene fibers, polyfluoroethylene fibers, etc. to a near limit.

Synthetic fibers fibrillated by strong shear forces can be used as binders. Furthermore, fibrillated heat-resistant organic fibers such as wholly aromatic polyamide fibers and phenol-formaldehyde fibers can also be used.

Further, any fiber other than those mentioned above can be used as long as it is fibrillated to have a single fiber diameter of 10 microns or less.

Note that the fiber diameter of the binder must be 1 l-1:10 μm or less, and if it is 10 μm or more, the binder has no effect.

Further, the fiber length of the binder is preferably longer than the maximum fiber length of the inorganic fibers having a fiber length distribution, but is not particularly limited. The smaller the fiber diameter of the organic fiber used as a binder is compared to the fiber diameter of the inorganic fiber, the more the binding effect can be enhanced by adding a small amount. Further, the reason why the binder is limited to fibrous is that the inorganic fibers are bound together without reducing the voids between the inorganic fibers, so that the impregnating properties of the inorganic paper according to the present invention are not deteriorated.

Furthermore, in one embodiment of the present invention, a wet paper strength agent may be added to improve the water resistance and solvent resistance of the produced inorganic paper. Examples of wet strength agents include urea-formaldehyde resins.

Water-soluble substances such as melamine-formaldehyde resin, polyamide-polyamine-epichlorohydrin resin can be used.

The inorganic paper according to one embodiment of the present invention is composed of the above-mentioned material and can be obtained, for example, by the manufacturing method shown below. That is, by the above method, the inorganic fibers having a fiber length distribution and the binder are uniformly dispersed in a dispersion medium such as water and an organic bath agent to obtain a dispersion liquid, and the binder is uniformly distributed on the surface of the inorganic fibers. After the mixture is mixed, paper is made using a normal paper machine using a wire mesh that does not allow inorganic fibers to pass through. An inorganic paper according to an embodiment of the present invention is obtained by peeling the mixture of fibers and binder remaining on the mesh from the mesh and drying under pressure near the fusion temperature of the binder. Hereinafter, this invention will be explained in detail with reference to Examples, but the invention is not limited to these Examples.

Example 1 Glass roving material with a single fiber diameter of 9 μm (manufactured by Central Glass Co., Ltd.) Total fiber length 3 mIn + 11 rm + 0.5
Cut each piece into lengths of 'Inm and weigh 30 g+ of 3 pieces.
1 mm 60 g +0.5 mm80. ! i' to 30
The mixture was weighed into a container and added to 30 g' of milled fiber (manufactured by Central Glass Co., Ltd.) having an average fiber length of 0.122 mm. Add 20A of water to this container, and add microfibrillated cellulose fiber (MFO) as a binder.
■, aqueous solution with fiber content of 2%, manufactured by Daicel Chemical Co., Ltd.) ss
Add s and p2 and mix with a stirrer for about 10 minutes. Then,
This dispersion liquid is transferred to a pulper (manufactured by Kumagai Uki Co., Ltd.) and stirred until the glass fibers are uniformly dispersed. To confirm the dispersion of the glass fibers, take a small amount of the dispersion liquid into a 5QOee measuring cylinder, add a large amount of water, mix thoroughly, and visually confirm the dispersion state of the fibers. If the glass fibers are no longer aggregated, the stirring of the pulper is stopped and this dispersion is used as a stock solution for papermaking.

Using 250 cc of this dispersion, paper was made using a square sheet machine (manufactured by Kumagaya Uki Co., Ltd.). After paper making.

A glass paper according to an embodiment of the present invention having a thickness of 0.26 mm and a size of 250×250 mm was obtained by drying at 140° C. using a rotary dryer. The properties of the glass paper are shown in Table 1.

Example 2 Short carbon fibers (Fure Carbon ■, manufactured by Kureha Chemical Co., Ltd.) with a fiber diameter of 12.5 μm and an average fiber length of 3.0 mm and milled carbon fibers with a fiber diameter of 12.5 μm and an average fiber length of 0.3 tnm. (Kureha Carbon ■, manufactured by Kureha Chemical Co., Ltd.) 2
5L Furthermore, the fiber diameter is 12.5μm and the average fiber length is 0.2V.
An's milled carbon fiber (Kureha Carbo J Kureha Chemical Co., Ltd.) 25y is 307! 9. In the container. This and water 1011f
In addition, microfibrillated cellulose fiber (MFO■, aqueous solution with fiber content of 2%, manufactured by Daicel Chemical Co., Ltd.) 350.9 was added as a binder for short carbon fibers, and paper was made in the same manner as in Example 1. A stock solution was prepared and paper was made in the same manner to obtain carbon paper according to another example of the present invention. The properties of the carbon paper are shown in Table 1.

Example 3 A 30II container with a fiber diameter of 3 μm and a fiber length of 50 to 100
,, alumina fiber (Safil ■, manufactured by Kou C Kosha, 1
Weigh 200p accurately, then add 207ml of water, and mix with a Coles type high-speed stirrer (manufactured by Takasaki Seisakusho) at a rotational speed of 40mm.
The mixture was set to GOr, p, and m and stirred for 5 minutes.

Take a part of this dispersion, 12 mesh, 42 mesh,
As a result of separating the alumina fibers through a sieving tester (manufactured by Kumagai Uki Co., Ltd.) equipped with 80 mesh and 150 mesh wire mesh, the results showed that 20% of alumina fiber was used for 12 mesh and 5% for 42 mesh.
2% alumina fiber was stuck in the 80 mesh, 18% in the 80 mesh, and 1% in the 150 mesh. Alumina fibers f, o, s, and p stuck to each mesh were taken and the average fiber length was measured using a projection microscope. As a result, the alumina fibers that stopped at 12 meshes were fibers of 1000 μm or more.

The average size of the 42 meshes was 800 μm. The average size of 80 mesh was 300 μm, and the average size of 150 mesh was 150 μm.

Next, the remainder 101 of the above dispersion (alumina fiber 1ωt
% containing) into a container and microfibrillated cellulose fibers (MFO■, aqueous solution with fiber content of 2%, Daicel Chemical Co. g) as a binder for alumina fibers 200. !
i+ was added, and 1D (manufactured by Wet Paper Co., Ltd.) was added, and the mixture was stirred until the alumina fibers were homogeneously dispersed, and this dispersion was used as a stock solution for papermaking.

Next, paper was made in the same manner as in Example 1 to a thickness of 0.21 m.
An alumina paper according to another embodiment of the invention of 250 x 250 zH was obtained. The properties of the alumina vapor are shown in Table 1.

Example 4 In the same manner as in Example 3, 200 y of alumina fibers were weighed into a container, 20 Iji of water was added, and the mixture was stirred for 4000 r with a Coles type stirrer.
・ppm, stirring was performed for 10 minutes. Then, Example 3
The fiber length distribution of alumina fibers was measured using the same method.

The measurement results are 8% for 12 mesh, 35% for 42 mesh,
80 meals and 41%.

It was 13% for 150 mesh. The average fiber length of the alumina fibers stopped at 80 mesh was 270 μm.

Next, in the same manner as in Example 3, the above dispersion liquid ioa was placed in a container, and MFO■-1z2QQl/, Kymen 557H■
After adding 0.1.9i and stirring to obtain a homogeneous dispersion, paper was made in the same manner as in Example 1 to obtain alumina paper according to another example of the present invention.

The properties of the alumina paper produced are shown in Table 1.

Example 5 In the same manner as in Example 3, alumina fiber 200II was weighed into a container, 6.5 #'i of water was added, and the mixture was stirred with a Coles type stirrer.
Stirring was performed at 000 rapsm for IQ minutes.

In order to examine the fiber length distribution of this dispersion, measurements were made in the same manner as in Example 3. As a result, 5% for 12 meshes, 23% for 42 meshes, and 37% for 80 meshes.

It was 35% for 150 mesh.

The average fiber length of alumina fibers stopped at 150 mesh is 1
It was 70 μm.

Next, in the same manner as in Example 3, for the above dispersion ″/eL51.

MFO■4019. After making a homogeneous slurry by adding 0.15.9 of Kymen 557H■, papermaking was carried out in the same manner as in Example 1 to obtain alumina paper according to yet another example of the present invention. The properties of the alumina paper are shown in Table 1.

Table 1 In order to investigate the ease with which the resin penetrated into the papers obtained in Examples 1 to 5, that is, the impregnating properties and the properties of the molded product, the following epoxy resin faces were made from sea bream, and each paper was impregnated with 160% Dry for 10 minutes at ℃ to form a prepreg sheet (
A semi-cured sheet) was obtained. Fifteen sheets of the prepreg sheets were stacked and heated at 160°C.

Under the conditions of a molding pressure of 55 ky/cnl and a molding time of 50 minutes.

Laminate molding was carried out to obtain laminate plate 5 using the paper obtained in Examples 1 to 5 as a reinforcing material. The resin impregnation of all five glaze laminates is completed in a relatively short period of time, and the molded appearance is excellent.Furthermore, the fiber content in the laminate is high, and the fibers themselves have a small porosity and are filled with a large amount of reinforcing material. It was possible to obtain a laminate with a high temperature. On the other hand, for comparison, a commercially available glass mat (monz3o, manufactured by Central Glass Co., Ltd.) and a glass cloth (KRW580, manufactured by Central Glass Co., Ltd.) were impregnated with the same fest, and a laminate was produced in the same manner as above.

As a result, the content of reinforcing material (glass fiber) in the laminate was lower than that of the laminate obtained in Examples of the present invention. These results are shown in Table 2.

Epoxy resin face (manufactured by Yuka Shell Co., Ltd.) Table 2 [Effects of the invention] As explained above, this invention desirably uses inorganic fibers with a fiber diameter of 100 μm or less and a fiber length in the range of 2 to 500 times the fiber diameter. a step of adjusting and controlling the fiber length distribution, and using the adjusted and controlled inorganic fiber as a main component. By mixing fibrillated organic fibers with a fiber diameter of 10 μm or less as a binder and performing a paper-making process by dispersing them, the paper has a moderate porosity and excellent impregnability, and has uniform quality. It is possible to obtain a method for producing an inorganic bene formed using as little binder as the conventional method.

Claims (3)

[Claims] (1) The fiber diameter is 100 μm or less, and the fiber length is 2 times the fiber diameter.
A process of adjusting and controlling inorganic fibers in a range of ~500 times to a desired fiber length distribution, and mixing the adjusted inorganic fibers as the main component with organic fibers fibrillated to a fiber diameter of 10 μm or less as a binder. A method of manufacturing inorganic paper that involves dispersing and making paper. (2) The method for producing inorganic paper according to claim 1, wherein the step of adjusting and controlling the inorganic fibers to have a desired fiber length distribution is a step of mixing inorganic fibers having different fiber lengths at a desired ratio. (3) The process of adjusting and controlling inorganic fibers to a desired fiber length distribution involves dispersing short fibers with a length of 1 to 50 mm in water with an adjusted concentration, and applying shear force to the fibers using a high-speed rotary machine. The production of inorganic paper according to claim 1, wherein a desired fiber length distribution is obtained by adjusting either the magnitude of the shearing force or the time during which the shearing force is applied. Law.