JPH03180588A - Polyether imide nonwoven cloth, polyether imide-inorganic fiber mixed nonwoven cloth and production thereof - Google Patents

Abstract

PURPOSE:To obtain the subject nonwoven cloth suitable for the production of a fiber-reinforcing thermoplastic resin molded article by dispersing short fibers containing polyether imide short fibers in water, accumulating the fibers on a water-permeable substrate to form a fiber mat, impregnating the mat with a solvent capable of dissolving polyether imide and drying the product. CONSTITUTION:A fiber mat is produced by dispersing short fibers containing polyether imide short fibers in water and accumulating the short fibers in the dispersion on a water-permeable substrate. A solvent capable of dissolving polyether imide (preferably methylene chloride) is uniformly impregnated into the fiber mat and then dried to obtain the objective nonwoven cloth containing polyether imide short fibers bonded with each other at the contacting points.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a polyetherimide nonwoven fabric, a polyetherimide mixed nonwoven fabric with inorganic fibers, and a method for producing these, which are suitable for use in the production of fiber-reinforced thermoplastic resin molded articles. Regarding.

[Conventional technology]

Fiber-reinforced thermoplastic resin moldings are used in various fields, and manufacturing methods include injection molding of molten resin mixed with reinforcing short fibers into a mold, and heating of reinforcing fiber tow or woven fabric. A method of molding a material impregnated with a plastic resin, in which reinforcing fiber strands are opened using static electricity, thermoplastic resin powder is attached, and then heated and melted to form a tape-shaped strand, which is then molded. Method (Tokuko Sho 47-3
6467), a method of laminating a reinforcing fiber fabric and a thermoplastic resin film and hot pressing (Japanese Patent Laid-Open No. 63-87
(Refer to Publication No. 228), thermoplastic resin fibers and reinforcing fibers are mixed to make a mixed Va fabric.

A method is known in which a plurality of mixed fiber fabrics are laminated and hot pressed (see Japanese Unexamined Patent Publication No. 1-45841).

However, each of these methods had the following drawbacks. That is, in the injection molding method, the content of reinforcing fibers cannot be increased, and the reinforcing fibers break during injection molding, resulting in a reduction in the reinforcing effect. In the case of the method of impregnating a reinforcing fiber fabric with a thermoplastic resin solution and forming the bottom shape, the fabric itself becomes hard, resulting in poor mold conformability.

How to attach thermoplastic resin powder to strands.

Difficult to apply resin uniformly. The method of laminating a reinforcing fabric and a thermoplastic resin film has poor mold resistance in the case of a three-dimensional mold, and also cannot achieve sufficient impregnation.

In the case of mixed fiber fabrics, the moldability during molding is improved, but
There is a weaving difficulty in mixing different types of yarns with completely different properties.

These drawbacks naturally occur even when polyetherimide is used as the thermoplastic resin.

[Problem to be solved by the invention]

In order to eliminate the above-mentioned drawbacks in the production of fiber-reinforced thermoplastic resin molded articles using polyetherimide, the present invention has developed a base material with good mold compatibility that can be used in place of the conventionally used thermoplastic resin film. The purpose of this project was to develop a base material that can be manufactured more easily than 1am or blended fabrics and can be used in place of mixed fiber fabrics.

That is, an object of the present invention is to provide a polyetherimide nonwoven fabric that has good moldability and is therefore suitable for use in place of a thermoplastic resin film in the production of fiber-reinforced thermoplastic resin molded articles. .

Another object of the present invention is to provide a mixed nonwoven fabric of polyetherimide and inorganic fibers that can be easily and inexpensively produced and is suitable for use in place of mixed fiber fabrics in the production of fiber-reinforced thermoplastic resin moldings. It is about providing.

Still another object of the present invention is to provide a method for producing the above-mentioned polyetherimide nonwoven fabric or polyetherimide-inorganic fiber mixed nonwoven fabric.

[Means to solve the problem]

The invention according to claim 1 is a nonwoven fabric made of polyetherimide staple fibers, characterized in that the polyetherimide staple fibers are welded together at their intersections.

The invention according to claim 2 is a nonwoven fabric consisting of 3 to 91% polyetherimide short fibers and 97 to 9% inorganic fiber short fibers, the polyetherimide short fibers together, and This is a polyetherimide-inorganic fiber mixed nonwoven fabric characterized in that polyetherimide short fibers and inorganic fiber short fibers are welded together at their intersection points.

Furthermore, the invention according to claim 3 is a method of dispersing short fibers containing polyetherimide short fibers in water, accumulating the short fibers in the dispersion on a drainage substrate to form a fiber mat, and dispersing the short fibers in water. This method of manufacturing a nonwoven fabric is characterized by substantially uniformly impregnating a polyetherimide-soluble solvent into a mat, and then drying it.

Hereinafter, one aspect of the present invention will be explained in detail.

The method of the present invention described in claim 3 can produce both a polyetherimide nonwoven fabric made of polyetherimide and a nonwoven fabric obtained by mixing polyetherimide and inorganic fibers. First, a method for producing a polyetherimide nonwoven fabric will be explained.

Polyetherimide (hereinafter abbreviated as PEI) long fibers having a fiber diameter of 20 to 50 μm are made into chopped strands of an appropriate length. The length of the chopped strand at this time is preferably 5 to 20 m.

The reason will be explained later.

Next, put this chopped strand into the water.

Spread and disperse into filaments while stirring. Here, in order to disperse the fibers well in water and keep them in a dispersed state, it is preferable to use an appropriate dispersant.As the dispersant, commonly available surfactant-based dispersants 2
For example, Marbomerse PT and Shindesu KV (both manufactured by Matsumoto Yushi Kogyo) can be used, and their concentrations range from 0.1 to 0.
3% is appropriate. The dispersion concentration of PEI is 0.
0.02 to 0.2%, preferably 0.05 to 0.1%.

The PEI fibers in this dispersion are then accumulated on a free substrate using papermaking techniques to form a fiber mantle.

Although this process can be carried out either batchwise or continuously, a batchwise process using a paper machine shown in FIG. 1 will be explained as an example. The paper machine, designated as a whole by the reference numeral 1, comprises a paper machine main body 3 which accommodates a dispersion 2, a bottom part 5 which rotatably holds the paper machine main body 3 by a hinge 4, and a paper machine main body 3. It has a fixing member 6 fixed to the bottom part 5, a drainage base material 7 attached to the upper surface of the bottom part 5, a drain pipe 8 connected to the lower end of the bottom part 5, a pulp 9, etc. The dispersion liquid is put into the paper machine 1, and in a state where the PEL fibers are uniformly dispersed in the water, the valve 9 is opened to drain the liquid.

As a result, the water in the dispersion liquid 2 that has been introduced is transferred to the freeness base material 7.
The short PEI fibers are collected on the free-flowing substrate 7 and discharged through the drainage pipe 8 . In this way, when the water in the dispersion liquid 2 charged into the paper machine 1 has almost completely passed through the freeness base material 7, a fiber mantle made of PEI short fibers is uniformly formed on the freeness base material 7. . Here, the freeness base material 7 used is as follows.

Preferably, a net with a large number of small meshes is used. The net has a fiber diameter of 20 to 50 μm, although it varies depending on the length and fiber diameter of the PEL fibers used.

For fiber lengths of 5 to 20 m! The size of the 11th il is 0
．． 26~0°30+n, the aperture ratio is 50~60%
If the mesh is too large, the speed of the liquid passing through the net will increase and the rate of formation of the 9-fiber cloak will increase, but the amount of short fibers passing through the mesh will increase and the yield will decrease. Due to the generation of water flow, the fiber mat formed on the net becomes non-uniform. On the other hand, if the mesh is too small.

The net is easily clogged, and it takes time to form a fiber cloak. Furthermore, if fibers with different specific gravities are mixed and dispersed in two dispersions, and it takes time to form a fiber mat, the fibers with higher specific gravity will be in the lower layer of the dispersion, and even in the formed fiber mat. , the proportion of mi with high specific gravity in the lower layer of the Sa fiber mantle increases.

Therefore, the size of the 'i4th eye is selected so as not to cause these defects.

After forming the fiber mat on the free-flowing base material 7, the paper machine main body 3 is rotated in the direction of the arrow around the hinge 4, and the fiber mantle is taken out together with the free-flowing base material 7.

Excess water is removed from the fiber mantle, and when the fiber mantle still contains some water, a solvent capable of dissolving PEI is sprayed uniformly into the fiber mat. As the solvent, chlorinated aliphatic hydrocarbon compounds such as methylene chloride and trichloromethane can be used, but methylene chloride is preferred from the viewpoint of ease of handling. The following explanation assumes that methylene chloride is used. As mentioned above, when methylene chloride is supplied while the fiber mantle retains some moisture, methylene chloride and water have some compatibility, so methylene chloride is easily distributed throughout the fiber mantle, and the fiber mat The moisture content of the fiber mat when spraying with methylene chloride is usually 50.
-200%, preferably 80-120%. The amount of methylene chloride to be sprayed is 10-20% of the weight of the fiber mat.
% is sufficient.

How to impregnate a fabric cloak with methylene chloride.

In addition to the method of spraying, methods such as impregnating the material with methylene chloride while sandwiching it between nets or coating it with a roller are also possible.

The methylene chloride that penetrates the entire fiber mat partially dissolves the surface of the PH1 fibers. Therefore, the fibers become adhesive at their intersections. When the fiber mat is then dried, the methylene chloride evaporates, and the adhesive portions at the intersections of the fibers become adhesive, forming a nonwoven fabric in which the fibers are bonded to each other. Therefore, there is no need to add a separate adhesive to bond the fibers together.

Through the above steps, the nonwoven fabric according to claim 1, in which the short polyether fibers are welded together at their intersections, is produced.

The weight of the polyetherimide nonwoven fabric produced by the above method can range from 10 to 200 g/m''.

PEI short fibers constituting the nonwoven fabric were used with different fiber diameters and fiber lengths, and an experiment was conducted using the apparatus shown in FIG. The uniformity (formation) of the fiber mat was investigated.

The results are shown in Table 1, and the freeness base material 7 used
is a 65-mens stainless steel mesh with an opening of 0.
．． It was 28m long and had an aperture ratio of 51%. Moreover, the thickness of the manufactured nonwoven fabric was 0.15 m, and the basis weight was 20 g/m''.

No. 1 table From the results in Table 1, when the fiber length is 20 m or more.

Fibers tend to entangle with each other in the dispersion and form lumps, and if the length is shorter than 5 baits, the fibers tend to fall off from the net mesh, resulting in poor yield. Also, in terms of the uniformity of the fiber mantle, about 5 to 15 fi is appropriate. Therefore, the fiber length is usually 5 to 20 m, preferably 5 m.
~15m. The diameter of PEI fibers is not particularly limited, but as shown in Table 1, nonwoven fabrics can be produced without any problem at a diameter of about 20 to 30 μm.

Next, a method for producing the mixed nonwoven fabric of polyetherimide and inorganic fiber according to claim 2 by the method according to claim 3 will be explained.

Inorganic fibers include glass fiber, carbon fiber, aluminum
Glass fibers can be appropriately selected and used depending on the purpose of use, and will be explained below using glass fibers as an example. The PE mentioned above
[Similarly to the case of chisel, prepare chopped strands of PEI and glass fibers, mix them at a certain ratio, add them to water in which the dispersant is dissolved, and stir to form chopped strands of PEI and glass fibers. The concentration of fibers in the dispersion is 0.02 to 0.2.
%, preferably from O,OS to 0.1%. In this case as well, the dispersant may be a surfactant-based dispersant 2 that is generally commercially available, such as Marbomerse PT, Shindesu KV (
In either case, Matsumoto Yushi Kogyo Ws11m) can be used, and the appropriate concentration is 0°1-0.3%. The dispersion concentration of PEI is 0.02 to 0.2%, preferably 0.05 to 0.2%.
O11% is good.

This mixed dispersion liquid is put into the paper machine L shown in FIG. 1, and the valve 9
Open it and let the water drain. As a result, a fiber mat containing a mixture of PEI and glass fibers is formed on the free-flowing substrate 7. At this time, the PEI and glass TA fibers that were uniformly dispersed in the dispersion liquid 3 are deposited on the free-flowing substrate 7, so that the PEI and glass fibers are uniformly mixed in the formed fiber mantle. It becomes. Note that if it takes time to form a fiber mat, PEf and glass fibers may separate in one dispersion due to the difference in specific gravity.

It is desirable to set the speed at which the drained liquid passes through the freeness substrate 7 so that the formation of the fiber mat is completed before such separation occurs.

The fiber mantle is taken out from the paper machine 1, excess moisture is removed, and then a PEI-soluble solvent 1, such as methylene chloride, is sprayed so as to uniformly permeate the entire fiber mantle. Then, the entire fiber mat is wet.

Methylene chloride quickly soaks into the entire fiber mat. The methylene chloride that soaks into the fiber mat partially dissolves the surface of the PEI fibers and makes the PEI fiber surfaces sticky.

As a result, fiber-to-fiber adhesion occurs between fiber-to-fiber intersections, ie, between PEI fibers and PEI and glass fibers. After that, this fiber cloak is dried,
When methylene chloride is removed, the adhesion between the fibers becomes adhesive, and a mixed nonwoven fabric containing PEI and glass fibers is obtained.

The basis weight of the polyetherimide-glass fiber mixed nonwoven fabric produced by the above method is 10 to 200 g/m.
It is possible within the range of

The mixing ratio of glass fibers can range from 9 to 97% by weight, and the mixing ratio is determined depending on the purpose and use.

Any glass fiber can be used as long as it can be dispersed into filaments by stirring in water.
Preferably, a treatment liquid containing a small amount of lubricant is applied to a silane surface treatment agent during spinning.

The fiber diameter of the glass fiber is 6 to 17 μm, and the fiber length is 5 to 20 μm.
Table 2 shows the results of an experiment on the dispersibility in the liquid and the uniformity (formation) of the fiber cloak using the apparatus shown in Figure 1 for M+.The mixing ratio of glass fiber and PEI was 75. :PE125, PEI fiber length is the same as glass fiber fiber length, PEI fiber diameter is 31μm, target basis weight of nonwoven fabric is 40g/m" From Table 2, a mixture of PEI and glass fiber. In the case of non-woven fabrics, the shorter the fiber length and the smaller the fiber diameter, the better the dispersibility and uniformity in the liquid. However, if the fiber length is too short or the fiber diameter is too small, the freeness group of the glass fiber will deteriorate. It may clog the material or easily pass through the free-flowing substrate.

Also, if the fiber diameter is too large or the fiber length is too long.

As the filaments refocus in water, their dispersibility in the liquid is disturbed. Therefore, in the case of a mixed paper of PEI and glass fiber, the fiber diameter of the glass fiber is 9 to 13 μm.

Those having a fiber length of 5 to 150 are suitable.

Although the method of the present invention has been described above using a batch method using the apparatus shown in FIG. 1, the manufacturing method of the present invention is not necessarily limited to this, and can also be carried out in a continuous method as shown in FIG. That is, in FIG. 2, only PH1 short fibers or PEI short fibers and glass fiber short fibers are added to water containing a dispersant in 1 dispersion tank 1I to create a dispersion liquid 12, and the dispersion liquid is It is continuously supplied to the paper machine 13. In the paper machine 13, a paper making net 15, which is a drainage base material, is continuously running on a drainage board 16 at the bottom of the paper machine 13, and fibers are continuously accumulated on it to form a fiber mat 15. Ru. After the fiber mat 15 passes through a suction device 17 to remove excess moisture, it is transferred to an adjacent conveyor net 18 and sprayed with methylene chloride by a spray device 21 connected to a methylene chloride tank 20 containing methylene chloride 19. It is.

PEI short $111 with methylene chloride! The adhesion process is performed. Thereafter, the tackified fibers 77) 15 are sent to the dryer 22, where they are dried and the intersections of the fibers are welded together.

A nonwoven fabric is formed.

As described above, the method of the present invention partially dissolves the surface of PEI to make it sticky without adding a new binder component as a binder, makes the fibers stick to each other at the intersections of the fibers, and removes the stickiness by drying the solvent. This method replaces adhesion and obtains a nonwoven fabric.

The PE1 hand-woven fabric according to claim 1 and the PEI-inorganic fiber mixed nonwoven fabric according to claim 2, which are produced by the above method, have fibers welded to each other, so they are simply deposited fibers, or This is because the bonds between the fibers are greater than when the fibers are simply intertwined.

The fibers do not fall off (and are extremely easy to handle.

The PEl nonwoven fabric and the PEl-inorganic fiber mixed nonwoven fabric according to the present invention can be suitably used as a base material for a fiber-reinforced thermoplastic molded article. That is, a plurality of Pel-inorganic fiber mixed nonwoven fabrics alone or a plurality of mixed nonwoven fabrics and PEl nonwoven fabrics are laminated and fitted into a mold, and the bottom is formed using a hot press or an autoclave mold. PEI melts due to heat and pressure and becomes integrated with inorganic fibers.

Upon cooling, it becomes a fiber-reinforced thermoplastic molded product. When used as a base material for such a fiber-reinforced thermoplastic resin molded article, it is appropriate that the content of non-mta fibers is about 10 to 75%.

Here, since no binder is used in the nonwoven fabric used, problems such as RTI and quality deterioration of carvings do not occur, and P
Since the El nonwoven fabric has better mold conformability than a thermoplastic resin film, it has the advantage that the bottom shape can be easily formed.

Furthermore, the PEL nonwoven fabric can also be used to improve the surface smoothness of the molded product and to finely adjust the inorganic fiber concentration of the molded product. In other words, PE with low basis weight
By laminating a nonwoven fabric on the surface, the surface smoothness of the molded product can be improved, and the laminated PEL
- The concentration of inorganic fibers can be adjusted by inserting a PEL nonwoven fabric with a small basis weight into an appropriate location of the inorganic fiber mixed nonwoven fabric. Since the PEI-inorganic fiber mixed nonwoven fabric has a uniform mixture of PEI and inorganic fiber, the quality of the TC-shaped product is good, and it is easier to manufacture and cheaper than mixed fiber fabric.

PEl nonwoven fabric and PEl-inorganic fiber mixed nonwoven fabric.

It is not limited to the case where these are used alone, but it is also possible to use them together with a mixed fabric of thermoplastic resin fiber yarn and reinforcing fiber yarn. That is, PEL nonwoven fabric or PE
A molded article can be obtained by laminating l-inorganic fiber mixed nonwoven fabrics and hot pressing.

In addition, the PEL nonwoven fabric of claim 1 can be used as various filters, especially as a filter for high temperature gas of 250°C or less.
It is also useful as a filter for water-based objects to be filtered.

[Example 1] PEI short fibers with a filament diameter of 31 μm and a fiber length of 10 tm were added to water containing 0.1% of the dispersant Marbomerse PT (specially manufactured by Matsumoto Yushi Kogyo) dissolved in 1 fiber. Add and stir so that the concentration is 0.2% to obtain 1 dispersion. This dispersion was added to the first
The paper is put into the paper machine 1 shown in the figure. Freeness base material 7 for paper machine 1
With a 65 mesh stainless steel net.

A net with a mesh opening of 0.2'8 m and an opening ratio of 51% was used. Valve 9 was opened, and the water passing through the net was drained through the drain pipe to form a PEIm¥1 mat on the net. About 20% of the weight of the fiber mat is evenly sprayed with methylene chloride onto the still wet fiber cloak. After spraying, the mixture was allowed to stand for about 2 minutes and then dried to obtain a PEL nonwoven fabric with a thickness of 0.15 nm and a basis weight of 120 g/m''.

[Example 2] PEI staple fiber used in Example 1 and filament diameter 10
Glass fiber with a fiber length of 10 m in μm is 25 near 5 in weight ratio.
1. Dispersant MABOMERSE PT
(Specially manufactured by Matsumoto Yushi Kogyo) was added to water in which 0.2% of the fibers were dissolved so that the fiber concentration was O.1%, and the fibers were uniformly dispersed by stirring to obtain a dispersion.

The dispersion was prepared in the same manner as in Example 1, and the paper machine l shown in FIG.
Pel-glass fiber mixture fiber 7 is placed on the net.
7 to form. Methylene chloride is sprayed onto the fiber mat in an amount equivalent to 15% of the weight of the cloak, evenly over the entire surface of the cloak. When it dries after being left for 2 minutes, the thickness is 0.
A PET-glass fiber mixed nonwoven fabric having a length of 4'5 m and a basis weight of 54 g/m'' was obtained.

[Example 3] The PEI short fibers and glass fibers used in Example 2 were
The mixed fibers made at a ratio of 40:60 with I were added to water in which 0.3% of the dispersant Marpomerse PT (specially manufactured by Matsumoto Yushi Industries) was dissolved, so that the fiber concentration was 0.15%, and the mixture was uniformly dispersed by stirring. I got the liquid. From this dispersion, a fiber mat of PEl-glass fiber mixture was obtained on a net in the same manner as in Example 1. Methylene chloride in an amount corresponding to 20% of the weight of the fiber mat is sprayed uniformly over the entire surface of the cloak. Leave it for 2 minutes and then dry.

A PEl-glass fiber mixed nonwoven fabric was obtained. Thickness is 0.53
The U1 date amount was 83.0 g/m''.

〔Effect of the invention〕

Since the PEI nonwoven fabric of the present invention has PEI fibers welded at their intersections, it has a higher density and can be formed more easily than a mat made by simply laminating or intertwining fibers, and is easy to handle. Moreover, since no binder is used, there is no problem of quality deterioration caused by the binder when it is used as a base material for a single fiber-reinforced thermoplastic resin molded product, and the mold conformability is good, so the bottom shape can be easily formed.

Thus, it is extremely useful as a base material for fiber-reinforced thermoplastic resin moldings. In addition, uses other than this use 2, for example,
It can also be used for filters, etc.

The PEL-inorganic fiber mixed nonwoven fabric of the present invention also has the same effects as the above PEL because the fibers are welded in the same way as the above PEI nonwoven fabric, and since it has inorganic fibers, It can be used in place of the previously used mixed fiber fabric made of thermoplastic resin fibers and reinforcing fibers. Furthermore, this mixed nonwoven fabric is easier to manufacture and cheaper than mixed fiber fabrics.

According to the manufacturing method of the present invention, the above-mentioned PEI nonwoven fabric or PEl-inorganic fiber mixed nonwoven fabric can be produced by a simple and low-cost method without adding a binder. In particular, when producing a PEl-inorganic fiber mixed nonwoven fabric, PE1 and inorganic fibers are mixed in a dispersion liquid.
Extremely uniform mixing is possible;

The mixing ratio of PEI and inorganic fibers can be freely selected.

In this way, it is possible to obtain a PEl-inorganic fiber mixed nonwoven fabric that is extremely uniformly mixed.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing one example of an apparatus used to carry out the method of the present invention, and FIG. 2 is a schematic side view showing another example. ■-・-Paper machine, 2-・-Dispersion, 3-Paper machine main body, 4
...Hinge, 5...-bottom, 7-...Drainage base material, 8
-・-Drainage pipe 9...Valve, 11-・Dispersion tank, 1
2--Dispersion liquid, 13--Paper machine, 14--Paper making net, 15--Fiber cloak 16 Drainage board, 17--
Suction device, 18--Conveyor net, 19--
Methylene chloride, 20-methylene chloride tank. 21-・Spray device, 22-・Dryer.

Claims (3)

[Claims] (1) A nonwoven fabric made of short polyetherimide fibers, characterized in that the short polyetherimide fibers are welded together at their intersections. (2) A nonwoven fabric consisting of 3 to 91% by weight of polyetherimide staple fibers and 97 to 9% of inorganic fiber staples, which include both polyetherimide staple fibers and polyetherimide staple fibers. A polyetherimide-inorganic fiber mixed nonwoven fabric characterized in that short inorganic fibers are welded together at their intersection points. (3) Dispersing short fibers containing polyetherimide short fibers in water, accumulating the short fibers in the dispersion on a free-flowing substrate to form a fiber mat, and adding polyetherimide soluble fibers to the fiber mat. A method for producing a nonwoven fabric containing short polyetherimide fibers, which comprises impregnating a solvent almost uniformly and then drying the fabric.