JPH03193416A - Method for impregnating roving with resin powder - Google Patents

Abstract

PURPOSE:To excellently open roving fiber and to uniformly impregnating the opened roving fiber with thermoplastic resin powder by imparting static electricity to the roving fiber and opening this roving fiber and thereafter introducing the opened roving fiber into a fluidized bed when the roving fiber is introduced into the fluidized bed and this roving fiber is impregnated with thermoplastic resin powder. CONSTITUTION:Roving fiber 10 supplied from the roving bobbins 11 is introduced into an electrostatic opening device 20. Therein static electricity is imparted to the roving fiber 10. Thereby this roving fiber 10 is opened into every piece of filament fiber. Plenty of roving fiber 10 opened by such a way is passed through a comblike or annular guide eye 30 and aligned in the prescribed shape e.g. a thin band shape. Thereafter the robing fiber 10 is introduced into a fluidized bed 40 equipped with a porous bottom plate 41 and a turn roll or turn bar 42. Thereby the roving fiber is excellently opened into every piece of filament in the fluidized bed 10. The roving fiber is uniformly and sufficiently impregnated with thermoplastic resin powder.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for satisfactorily opening roving fibers and uniformly impregnating them with thermoplastic resin powder.

(Prior Art) A method for manufacturing thermoplastic prepreg by introducing roving fibers such as glass roving into a fluidized bed, impregnating it with thermoplastic resin powder, and heating it to melt the resin powder is Are known.

In accordance with this method for producing thermoplastic prepreg, a large number of roving fibers are fed out from a roving bobbin,
Generally, the fibers are passed through a comb-shaped or annular path and arranged into a predetermined shape, such as a thin strip, and then introduced into a fluidized bed where they are opened as they pass through turn rolls or turn bars, and are then made into thermoplastic fibers. Impregnated with resin powder.

(Problem to be Solved by the Invention) In this case, each roving fiber has an uneven cross-sectional shape due to curling, and as a result, the roving fiber tends to be tangled when passing through the yarn path (in a fluidized bed, the roving fiber may not be opened uniformly and sufficiently.

When such roving fibers are impregnated with thermoplastic resin powder, the resin powder is not uniformly impregnated, resulting in uneven impregnation.This can be heated to melt the resin powder, for example, to create a thin strip-shaped prepreg. , the width of the prepreg becomes narrow, the thickness of the prepreg becomes uneven, and defects (holes) occur in the prepreg, making it impossible to obtain a good prepreg.

The present invention solves the above-mentioned problems, and its purpose is to provide a method for satisfactorily opening roving fibers and uniformly impregnating them with thermoplastic resin powder.

(Means for Solving the Problems) The method of impregnating the roving with resin powder of the present invention includes imparting static electricity to the roving fiber when introducing the roving fiber into a fluidized bed and impregnating it with the thermoplastic resin powder. The method is characterized in that the fibers are opened by a method and then introduced into a fluidized bed, thereby achieving the above object.

The method of the present invention will be explained below with reference to the drawings.

In FIG. 1, 10 indicates a large number of roving bobbins 11.
The roving fibers 10 include glass fibers, non-conductive filament fibers such as aramid fibers, polyester fibers, nylon fibers, aromatic polyamide fibers (Kevlar fibers), and polyethylene fibers. Roving fibers are used, which are made by bundling a large number (several tens to thousands) of roving fibers (thickness of several microns to several tens of microns) using a small amount of binder. The amount of binder is preferably small in order to facilitate opening of the roving fibers, and a binder containing 0.1 to 0.4% by weight is usually used.

The roving fibers 10 drawn out from the roving bobbin 11 are introduced into an electrostatic fiber opening device 20, where static electricity is applied to the roving fibers 10, whereby the roving fibers 10 are opened into individual filament fibers.

As shown in FIG. 2(a), the electrostatic opening device 20 is composed of a needle-shaped electrode plate 21, a ground plate 22, and a DC power supply 23 for applying a high voltage. Then, the roving fiber 10 is introduced between the needle-shaped electrode plate 21 and the ground plate 22 (perpendicular to the drawing), where the DC power source 2
3, a high voltage is applied between the needle-shaped electrode plate 21 and the ground plate 22, thereby charging the roving fiber 10. The charged roving fibers 10 are opened by the repulsive force of the charges.

The electrostatic opening device is not limited to the device described above, for example, the device shown in Fig. 2 (
A device as shown in b) is also used.

The electrostatic fiber opening device 20'' shown in FIG. In this case, the roving fiber 10 is introduced into a thin metal tube 21', where the DC power source 23' connects the thin metal tube 21'' to the thick metal tube 21''. metal tube 22
A high voltage is applied between the roving fibers 10 and the roving fibers 10, thereby charging the roving fibers 10, and the charged roving fibers 10 are spread and spread toward the thick metal tube 22' at the exit of the thin metal tube 21''.

The voltage applied to the electrostatic opening device 20 or 20' is:
Generally 20-50 KV is preferred. If it is less than 20 KV, it is difficult to open the fibers properly, and if it exceeds 50 KV, sparks may be generated, which is dangerous. Furthermore, if the tension of the roving fibers 10 passing through the electrostatic opening device 20 or 20' is too strong, each filament fiber will not spread properly and will not be opened properly. Therefore, the tension of the roving fiber 10 fed out from the roving bobbin 11 is adjusted to an appropriate strength.

A large number of roving fibers 10 opened in this way are passed through a comb-like or annular thread path 30 and arranged into a predetermined shape, for example, a thin strip, and then connected to a porous bottom plate 41 and a turn roll or turnper 42. is introduced into a fluidized bed 40 equipped with.

In the fluidized bed 40, thermoplastic resin powder 50 is blown up above a porous bottom plate 41 by air pressure and kept in a floating state. The large number of roving fibers 10 introduced into the fluidized bed 40 widen the gaps between the filament fibers due to air pressure, and the thermoplastic resin powder 50 in a suspended state is held in the gaps, and is pressed uniformly by the turn roll or turnper 42. The fibers are opened and impregnated with resin powder 50.

As the thermoplastic resin powder 50, powder of polyethylene, polypropylene, vinyl chloride resin, engineering resin such as polyphenylene sulfide, polyether sulfone, etc., and having a particle size of 10 to 300 μm is preferably used. The above-mentioned roving fibers 10 are preferably used so as to be contained in a range of generally 60% by volume or less with respect to the thermoplastic resin powder 50.

A large number of roving fibers 10 impregnated with thermoplastic resin powder 50 are pressed against a turn roll or turnper 42 provided in a fluidized bed 40 to form a thin strip 15'. The thin strip 15'' may be made into a single thin sheet using one roving fiber 10 unwound from - roving bobbins 11, or a thin strip 15'' may be formed by using a plurality of roving fibers unwound from a plurality of roving bobbins 11. 10 may be used to make one relatively wide sheet, or two or more sheets may be made and laminated and integrated as shown in the figure.

The thin strips 15'' made of two upper and lower sheets are passed through a pair of heating rolls 60 and into a heating furnace 70, where they are coated with resin powder 5.
0 is melted, and the roving fiber IO and the resin powder 50 are integrated. Thereafter, it is passed through a pair of cooling rolls 80 and wound up by a winder 90 to obtain a thin strip-shaped prepreg 15.

This prepreg 15 is used as a core material, and this core material is coated with a thermosetting resin such as unsaturated polyester or a thermoplastic resin such as vinyl chloride resin to make a long fiber-reinforced material for rain gutters, decking materials, etc. When a plastic resin composite molded article is produced, one with low heat stretchability can be obtained.

(Function) As in the method of the present invention, when an appropriate voltage of static electricity is applied to the roving fibers, the roving fibers are opened, and the roving fibers opened in this way have a substantially constant cross-sectional shape and pass through the yarn path. No sagging occurs when applying. Therefore, the roving fibers are well opened into individual filaments in the fluidized bed, and the roving fibers are uniformly and sufficiently impregnated with the thermoplastic resin powder.

(Example) Examples and comparative examples of the present invention are shown below.

Example In this example, a thin strip-shaped prepreg sheet was manufactured by the method shown in FIG.

First, a 60-L roving bobbin 11 of glass roving fiber ($14,400, manufactured by Nippon Electric Glass Co., Ltd., in which filaments with an average diameter of 23 μm are bundled with a 0.4% by weight polyester binder) was prepared. Of these, 30-
The 30-rules were arranged in parallel on the upper stage, and the remaining 30-rules were arranged in parallel on the lower stage.

Glass roving fibers 10 were drawn out from each roving bobbin 11 and introduced into an electrostatic opening device 2°.

Then, between the needle-shaped electrode plate 21 and the ground plate 22,
A voltage of KV was applied to charge and spread the roving fibers 10. The tension when paying out the glass roving fiber 1o from the roving bobbin 11 is determined by the electrostatic opening device 2.
Adjustments were made while observing the spread state of the filament fibers opened at o.

Next, the fibers were passed through a comb-like thread path 30 and arranged in a band shape, and then introduced into a fluidized bed 40. In this fluidized bed 40, the average particle size is 10
0μ, melting point 180°C vinyl chloride resin blend powder (TK-
400 (manufactured by Shin-Etsu Chemical Co., Ltd.) 50 was impregnated to prepare two thin strips (upper and lower) of 15 mm.

Thereafter, the two strips 15'' are laminated together by passing them through a pair of heating rolls 60 heated to 190°C, and then the resin powder 50 is melted in a heating furnace 70 at 220°C, and the roving fibers 10 and It was completely integrated with the resin powder 50, then cooled by passing through a pair of cooling rolls 80 cooled to 30° C., and wound up by a winder 90 to create a thin strip-shaped prepreg sheet 15. The line speed is 0.4m/
It was a minute.

This band-shaped prepreg sheet 15 has a glass fiber content of 32% by weight, a sheet width of 18.5 cn+, a sheet thickness distribution of 0.45 to 0.41 ttm, and a surface roughness of 9 μm, and has glass fiber fraying and defects (holes). ) did not occur at all.

Comparison Example The same procedure as in the above example was carried out except that the electrostatic fiber opening device 20 was not used.

In this case, the obtained band-shaped prepreg sheet 15 has a glass fiber content of 39% by weight, a sheet width of 14 cm, a sheet thickness distribution of 0.45 to 0.55 mm, and a surface roughness of 40 μm.
The number of times the glass fiber is dented is 36 times/hour, and there are defects (holes).
The average number of particles was 1.5 pieces/m.

(Effect of the invention) As described above, when introducing roving fibers into a fluidized bed and impregnating them with thermoplastic resin powder, if the roving fibers are opened by applying static electricity and then introduced into the fluidized bed, The glass fibers are prevented from fraying, the opening properties of the roving fibers are improved, and the roving fibers can be uniformly and sufficiently impregnated with thermoplastic resin powder.

Therefore, according to the method of the present invention, a prepreg with relatively uniform width and thickness and no defects (holes) can be obtained, and such prepreg can be used to mold high-quality fiber-reinforced thermoplastic resin. body can be manufactured.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram showing an example of the method of the present invention, Figure 2 (a)
2 is a front view showing an example of the electrostatic fiber opening device used in the method of the present invention, and FIG. 2(b) is a side view showing another example of the electrostatic fiber spreading device used in the method of the present invention. 10... Roving fiber, 15... Prepreg, 2
0... Electrostatic opening device, 30... Yarn guide, 40...
Fluidized bed, 42... Turn bar, 50... Thermoplastic resin powder, 60... Pair of heating rolls, 70... Heating furnace, 80... Pair of cooling rolls, 90... Winding machine .

Claims (1)

[Claims] 1. When the roving fibers are introduced into the fluidized bed and impregnated with thermoplastic resin powder, the roving fibers are opened by applying static electricity and then introduced into the fluidized bed. How to impregnate powder.