JPH04135742A - Fiber reinforcing resin sheet for thermoforming use and method of its manufacture and thermoforming - Google Patents

Abstract

PURPOSE:To obtain a resin sheet impregnated sufficiently with resin as far as between monifilaments, excellent in mechanical property and good in the surface condition by a method wherein a magnetic powder-free thermoplastic resin sheet is adhesively layered on at least one side of a magnetic powder-containing fiber reinforcing thermoplastic resin sheet. CONSTITUTION:A reinforcing fiber bundle 1 having magnetic powder-containing resin powder 2 attached thereto is passed between a take-up driving roll 40 and a pinch roll 41, cut by a cutter roll 50 into a predetermined short length, dropped onto a transfer part 61b of the lower side of an endless belt 61 and laid one upon another into a predetermined stacking thickness. On the other hand, the upper and lower thermoplastic resin sheets 4 free from magnetic powder are rewound on rewinding rolls 90 and 91 and supplied from the endless belts 60 and 61 of guide rolls 64 and 65 to transfer parts 60a and 61a. The thermoplastic resin sheet 4 free from the magnetic powder is layered on both sides of a stacked object 3 and thus formed into a three layer structure. In this way the fiber reinforced resin sheet for thermoforming use highly effective in fiber reinforcing performance and excellent in mechanical property can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a thermoformable fiber-reinforced resin sheet in which reinforcing fibers are integrally impregnated with a thermoplastic resin, a method for manufacturing the same, and a method for molding the sheet.

(Prior Art) Fiber-reinforced resin sheets for thermoforming containing particulate or fibrous magnetic powder are known.

For example, in Japanese Patent Application Laid-Open No. 63-1538, as shown in FIG. A fiber-reinforced resin sheet for thermoforming (stampable sheet) 6'', which is formed integrally with a layer 3'' of thermoplastic resin containing 2'' magnetic powder in the form of particles or fibers, is heated by high-frequency electromagnetic induction heating. However, a technique for molding it into an irregular shape has been disclosed.

In such fiber-reinforced resin sheets for thermoforming, the magnetic powder contained therein instantaneously generates heat due to the high-frequency magnetic field and melts the resin in a short time, reducing the heating time for sorting before molding. , which has the advantage of improving productivity.

(Problem to be Solved by the Invention) However, the above-mentioned conventional fiber reinforced resin sort 6 for thermoforming
' is a molten state in which two thermoplastic resin sheets are superimposed from the outside of two long fiber glass mats 1, and magnetic powder 2 is contained between the two long fiber glass cloaks 1. The long fiber glass mat 1" is made by sandwiching N3" of thermoplastic resin and passing it through a heating area and a cooling area while being held and conveyed by a pair of upper and lower endless heddles.
It is manufactured by melt-impregnating it with resin.

In such a manufacturing method, a long fiber glass cloak 1
It is not easy to sufficiently impregnate the thermoplastic resin between the monofilaments, and the physical properties of the resulting product (reinforcing effect of the glass cloak) are not fully exhibited. In addition, when manufacturing a fiber-reinforced resin sheet for thermoforming, for example, if the heating temperature is set relatively high and the glass mat is sufficiently impregnated with resin, the resulting fiber-reinforced resin sheet for thermoforming is There is a problem in that the glass fibers stand out on the surface of the resin sheet 6 and the surface condition deteriorates.

The present invention is intended to solve the above-mentioned problems.The purpose of the present invention is to disperse reinforcing fibers in monofilament units so that the resin is sufficiently impregnated even between the monofilaments, resulting in excellent physical properties and improved surface condition. An object of the present invention is to provide a good fiber-reinforced resin sheet for thermoforming, a method for manufacturing the same, and a method for molding the sheet.

(Means for Solving the Problems) The fiber-reinforced resin sheet for thermoforming of the present invention has magnetic powder on at least one side of a fiber-reinforced thermoplastic resin sheet containing particulate or fibrous magnetic powder. It is characterized by laminated and adhesively bonded thermoplastic resin sheets.

Furthermore, the method for producing a thermoforming fiber-reinforced resin sheet of the present invention involves introducing a reinforcing fiber bundle composed of a large number of continuous monofilaments into a fluidized thermoplastic resin powder containing magnetic powder. The resin powder is attached to the monofilaments of this fiber bundle, the fiber bundle with the resin powder attached is cut to a desired length, and the fiber bundle is dropped onto an endless belt to be accumulated. A thermoplastic resin sheet containing no magnetic powder is superimposed on at least one side,
It is characterized by passing through a heating area and a cooling area while being held and conveyed by a pair of upper and lower endless healds.

Furthermore, the method for molding a fiber-reinforced resin sheet for thermoforming of the present invention is characterized in that the above fiber-reinforced resin sheet for thermoforming is heated by high-frequency electromagnetic induction heating and molded into an irregular shape.

The above configuration achieves the above object.

As the reinforcing fiber bundle used in the present invention, a strand-like or roving-like fiber bundle composed of several hundred to several thousand continuous monofilaments is preferably used. A large number of reinforcing fiber bundles are generally used in parallel in consideration of the width, thickness, manufacturing speed, etc. of the fiber-reinforced resin sheet to be manufactured.

As the reinforcing fibers, fibers that are thermally stable at the melting temperature of the thermoplastic resin powder used are used. For example, inorganic fibers such as glass fibers, carbon fibers, silicon/titanium/carbon fibers, boron fibers, and fine metal fibers, and organic fibers such as aramid fibers, polyester fibers, and polyamide fibers are preferably used.

The diameter of the monofilament is preferably 1 to 50 μl. Further, when a reinforcing fiber bundle in which monofilaments are bundled with a binding agent is used, the amount of the binding agent attached is preferably 1% by weight or less, more preferably 0.5% or less. If the adhesion amount of the sizing agent exceeds 1% by weight, it becomes difficult to separate the reinforcing fiber bundle into monofilament units in the fluidized bed of the resin, and the impregnation of the resin between the monofilaments decreases.

In the present invention, the length of the reinforcing fiber bundle cut to a desired length is usually 0.5 to 500 mm, particularly 3 to 15 mm.
0 mm is preferred. The length of the cut reinforcing fiber bundle is 0
．． If the thickness is less than 5 mm, the reinforcing effect will be small, and if it exceeds 500 mm, it will be difficult to obtain a homogeneous fiber-reinforced resin sheet.

Further, as the thermoplastic resin powder used in the present invention, any resin that softens and melts when heated can be used. For example, polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyamide, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, polyvinylidene fluoride, polyphenylene sulfide, polyphenylene oxide, polyether sulfone, polyether ether ketone, etc. are used.

In addition, copolymers, graft resins, and blend resins containing the above resins as main components, such as ethylene vinyl chloride copolymers, vinyl acetate-ethylene copolymers, vinyl acetate-vinyl chloride copolymers, urethane-vinyl chloride copolymers, etc. Polymers such as acrylonitrile-butadiene-styrene copolymer, acrylic acid-modified polypropylene, maleic acid-modified polyethylene, etc. are also used.

As these resins, both resins obtained in powder form during polymerization and resins made into powder form by a pulverizer can be used. As for the particle size, the average particle size is preferably 2000 μm or less. If the average particle size exceeds 2000 μm, it becomes difficult to uniformly adhere the reinforcing fiber bundle between the monofilaments in a fluidized bed of resin.

Note that these resins may contain general additives such as stabilizers, lubricants, processing aids, plasticizers, and colorants.

Particulate or fibrous magnetic powder is uniformly mixed into these resin powders. Such magnetic powder may be any material that generates heat when placed in a high-frequency magnetic field, such as metals such as iron, cobalt, nickel, chromium, and aluminum; alloys such as nickel-iron and nickel-chromium; Metal oxides such as iron oxide, iron trioxide, nickel oxide, chromium dioxide, cobalt dioxide; other ferrites,
Examples include carbon fiber and carbon blank.

These magnetic powders are generally mixed in an amount of 0.05 to 70 parts by weight per 100 parts by weight of the resin powder. If the amount is less than 0.05 parts by weight, there will be little effect, and if it exceeds 70 parts by weight, the mechanical strength of the sheet will be significantly reduced.

In addition, in the present invention, the mixing ratio of the resin powder and the reinforcing fiber bundle is appropriately determined depending on the physical properties required of the fiber-reinforced resin sheet for thermoforming, but the reinforcing fibers in the sheet are 5 to 7.
Preferably it is 0% by weight. 70% by weight reinforcing fiber
If it exceeds 5% by weight, it will be difficult to obtain a sheet uniformly impregnated with resin, and if it is less than 5% by weight, the mechanical strength of the sheet will decrease.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic side view showing an example of an apparatus used for producing a thermoformable fiber-reinforced resin sheet of the present invention.

This device includes an unwinding roll 10 in which a roll on which a reinforcing fiber bundle 1 is wound is set, a container 20 in which thermoplastic resin powder 2 containing magnetic powder 2 is supplied, and a container 20.
A slinter 30 that adjusts the amount of resin powder 2 attached to the reinforcing fiber bundle 1 that has passed through the slinter 30, a rubber take-up drive roll 40 and a pinch roll 41 that rewind the reinforcing fiber bundle 1 from the unwinding roll 10, A cutter roll 50 cuts the reinforcing fiber bundles to which the resin powder 2 is attached to a desired length, and short-sized reinforcing fiber bundles to which the resin powder 2 is attached are accumulated, and this aggregate 3 or a laminate 5 to be described later is used. A pair of upper and lower endless belts 60 and 61 that pinch and convey, a heating means 70 and a cooling means 80
and unwinding rolls 90 and 91 for setting a roll around which a thermoplastic resin sheet 4 containing no magnetic powder is wound.

- A large number of ventilation holes are provided at the bottom of the container 20, and the configuration is such that gas such as air and nitrogen sent from the gas supply path is supplied into the container 20 through the ventilation holes in the direction of the arrow. The resin powder 2 supplied into the container 20 becomes fluidized by the jetting of the gas, forming a fluidized bed 2.
a is formed. S inside the container 20 and at the upper end of the wall.
A guide roll 21 for guiding the reinforcing fiber bundle 1 is provided.

The cutter roll 50 has a large number of cutting blades provided at a constant arrangement on the circumferential surface of the metal roll, and is combined with the take-up drive roll 40, so that the resin powder 2 is cut by the rotation of the cutter roll 50. The attached reinforcing fiber bundle is cut. Such rotary cutters are known.

The endless healds 60, 61 are set to continuously rotate and move in the same direction at approximately the same speed by driving drive rolls 62, 63 with a motor (not shown). Transfer parts 60a and 61a are formed on the upper endless belt 61 and the lower endless heald 60, respectively.
4 a and 61a are arranged vertically facing each other with gaps interposed therebetween.

The transfer section 61a of the lower endless belt 61 is longer than the transfer section 60a of the upper endless belt 60 (and extends forward from the front end of the transfer section 61a, and is open at the top).
b is formed. In some cases, the transfer portion 61b of the lower endless heald 61 may be formed by arranging another endless heald below without extending the transfer portion 61a of the lower endless heald 61. Such an endless heald 60,61 can be formed of a material having high strength and heat resistance, such as a steel heald, a stainless steel belt, a glass cloth reinforced Teflon belt, etc.

Transfer section 60 of the upper endless heald 60 and the lower endless belt 61
Heating means 70 are provided at opposing locations of a and 61a, respectively.
are arranged, and a cooling means 80 is arranged at the rear following the heating means 70. As shown in the figure, the heating means 70 preferably comprises a hot air circulation type or an electric heating type heating furnace, through which an endless heald 60, 61 is passed. In addition, a system in which the belt is directly heated while sandwiching the endless healds 60 and 61 by using heating rolls may also be adopted.

Inside the heating means 70, a plurality of pairs of guide rolls 71 are disposed at corresponding positions above and below. Moreover, the cooling means 80 is comprised of a plurality of pairs of guide rolls 81 at positions corresponding to the cooling blower and the top and bottom. The clearances between the upper and lower guide rolls 71 and 81 are adjustable. In addition, as the cooling means 80, in addition to the method of cooling by blowing air with a blower as described above, a method of cooling the guide roll 81 with water may also be adopted.

Next, a method for manufacturing a fiber reinforced resin sheet for thermoforming of the present invention will be explained using the above-mentioned apparatus.

As shown in FIG. 1, the reinforcing fiber bundle 1 composed of a large number of monofilaments is taken up by a take-up drive roll 40 and a pinch roll 41, and is not twisted from the roll around which the reinforcing fiber bundle 1 is wound. It will be rewound so that it doesn't exist. Then, this reinforcing fiber bundle 1 is attached to a guide roll 21.
is guided into the fluidized bed 2a. In addition, although only one reinforcing fiber bundle 1 is shown and explained in the figure for convenience, generally a large number of reinforcing fiber bundles 1 are used in parallel.

In this fluidized bed 2a, the reinforcing fiber bundle 1 is separated into monofilament units and opened by the ejection of gas, static electricity generated in the fluidized bed 2a, and the rubbing effect of the resin powder 2 containing the magnetic powder 2. The resin powder 2 enters between the monofilaments, is electrostatically captured, and adheres to the monofilaments. In this case, the width of the reinforcing fiber bundle 1 is divided into monofilament units,
It becomes somewhat wider because it is opened. The reinforcing fiber bundle 1 with the resin powder 2 attached passes between the slitter 30,
Excessive adhering resin powder 2 is removed. slinter 3
By adjusting the gap of 0, the amount of adhering resin powder 2 containing magnetic powder is adjusted.

The reinforcing fiber bundle 1 to which the resin powder 2 containing magnetic powder is attached is
After passing through the take-up drive roll 40 and the pinch roll 41, it is cut into short dimensions of a desired length by a cutter roll 50, and is fed onto the transfer section 61b of the lower endless belt 61 and accumulated to a predetermined thickness. be done.

On the other hand, two upper and lower thermoplastic resin sheets 4 that do not contain magnetic powder are rewound from the unwinding roll 90.91, and are respectively transferred from the position of the endless belt 60.61 of the guide roll 64.65 to the transfer parts 60a and 61a. Supplied.

Then, thermoplastic resin sheets 4 containing no magnetic powder are stacked on top and bottom of the stack 3 to form three layers. Subsequently, this laminate 5 is attached to a pair of upper and lower endless belts 60.6.
The molten material containing the magnetic powder between the filaments is transferred while being sandwiched between the filaments and supplied to the heating means 70 and heated to an appropriate temperature at or above the melting point of the resin constituting the resin powder 2. Impregnated with resin.

Here, the upper and lower endless belts 60 are
．． The clearance between the laminates 61 is adjusted, and the laminate 5 is pressurized with an appropriate pressure in the thickness direction. Due to this pressurization, the molten resin powder 2 flows and fills the gaps between the monofilaments, so that the resin constituting the resin powder 2 and the reinforcing fibers are well integrated, and at the same time, the surface does not contain magnetic powder. The thermoplastic resin sheets 4 are laminated and bonded well.

Subsequently, the clearance between the upper and lower endless belts 60, 61 is adjusted by the guide rolls 81 of the cooling means 80, and the heated laminate 5 is cooled to an appropriate temperature while being pressurized. In this way, a thermoformable fiber-reinforced resin sheet 6 having a predetermined thickness is manufactured.

Such a fiber reinforced resin sheet 6 for thermoforming of the present invention,
As shown in FIG. 2, thermoplastic resin sheets 4 that do not contain magnetic powder are laminated and bonded on both sides of a fiber-reinforced thermoplastic resin sheet 3 that contains magnetic powder 2. The thermoplastic resin sheet 4 that does not contain magnetic powder may be laminated and bonded to only one side of the thermoformable fiber-reinforced resin sheet 3 that contains magnetic powder. Note that l" is a reinforcing fiber.

The fiber-reinforced resin sheet 6 for thermoforming of the present invention produced in this manner is generally heated to a temperature at which the resin melts by high-frequency electromagnetic induction heating in a separate and independent process, and then molded into various irregular product shapes. Ru. A conventionally known method is employed as the high frequency electromagnetic induction heating method. In addition, the molding method
Known methods such as a vacuum method, compression molding, and press molding are employed.

(Function) As described above, the fiber reinforced resin sheet for thermoforming of the present invention has the following features:
Since it has a thermoplastic resin sheet that does not contain magnetic material on at least one surface, reinforcing fibers are prevented from protruding onto the surface compared to a conventional thermoplastic resin sheet that has reinforcing fibers on its surface.

In addition, in the method for producing a fiber-reinforced resin sheet for thermoforming of the present invention, resin powder containing magnetic powder is attached to a reinforcing fiber bundle in a fluidized bed of thermoplastic resin powder, and the resin powder is cut into a desired length. When the accumulated material is fed between a pair of upper and lower endless belts and heated and pressurized, the magnetic powder-containing resin is spread between the monofilaments of the fiber bundle due to the opening action of the fiber bundle in the fluidized bed. Thoroughly impregnated. Moreover, the process can be performed continuously.

Moreover, at this time, if a thermoplastic resin sheet containing no magnetic powder is superimposed on at least one side of the above-mentioned stack, and such a laminate is supplied between the above-mentioned pair of upper and lower endless belts and heated and pressurized, the above-mentioned Since the reinforcing fiber bundle is well impregnated with the resin containing magnetic powder, the above method does not require setting the heating temperature to high harsh conditions to promote resin impregnation as in the conventional technology. The laminate is laminated and bonded together. Therefore, reinforcing fibers are prevented from floating on the surface of the obtained fiber-reinforced resin sheet for thermoforming.

Furthermore, according to the method for forming a fiber-reinforced resin sheet for thermoforming of the present invention, the magnetic powder in the sheet instantly generates heat due to the high-frequency magnetic field and melts the resin in a short time, as in the conventional technology, so that The heating time for the sheet will be shorter.

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

1. Using the apparatus shown in FIG. 1, a thermoforming fiber-reinforced resin sheet shown in FIG. 2 was produced in the following manner, and this thermoforming fiber-reinforced resin sheet was molded.

As thermoplastic resin powder 2 containing magnetic powder, pulverized low-density polyethylene (specific gravity 0.92, average particle size 200μ
m) 100 parts by weight and iron powder as magnetic powder (average particle size 8
A uniform mixture of 20 parts by weight (0 μm) was used.

As the reinforcing fiber bundle 1, a roving-shaped glass fiber bundle (22
00g/km, and the adhesion amount of the sizing agent was about 0.3% by weight).

As the thermoplastic resin sheet 4 that does not contain magnetic powder, a high-density polyethylene sheet (width 450rr1m, thickness 1m
m, specific gravity 0.96).

Further, a glass cloth reinforced Teflon belt (width: 600 mm, thickness: approximately 1 cylinder) was used as the endless heald 60.61.

First, a large number of reinforcing fiber bundles l are continuously passed through a fluidized bed 2a of resin powder 2 containing magnetic powder to adhere the resin powder 2 between the monofilaments, and then the slitter 30
to remove excess resin powder and adjust the weight ratio of magnetic powder-containing resin powder and reinforcing fibers to 7:3,
Canter roll 5 so that the overall width is 450 mm.
0 was supplied.

This was cut into lengths of about 25 # by means of a counter roll 50, and was then dropped and fed onto the transfer section 61b of the lower endless heald. The supply amount is 61 at the lower endless belt transfer section with a width of 600 strokes.
Approximately 1660g/rr in a range of approximately 450mm in the center of b
Supply and accumulation were carried out so that f was obtained. At this time, the apparent thickness of the aggregate 3 was about 11 mm.

This aggregate 3 is sandwiched between upper and lower endless helmets 60 and 61 moving at a speed of 580+nm/min, and thermoplastic resin sheets 4 containing no magnetic powder are stacked on both sides of this aggregate 3. Together, the three-layer laminate 5 has a length of about 15
0011101, the resin powder 2 was melted by passing through a heating furnace 70 in which hot air of about 190° C. was circulated. At this time, the minimum gap between the endless healds 60 and 61 was adjusted to about 2.2 discs by the guide roll 71.

Subsequently, the laminate 5 in which the resin powder 2 is in a molten state is
It was cooled with a cooling blower 70 to produce a thermoformable fiber-reinforced resin sheet 6. At this time, Mugen Hell 1-60.61
The gap between them was adjusted to about 21 Wl by a guide roll 71. This fiber-reinforced resin sheet 6 for thermoforming has a width of about 45 mm.
The sheet had a thickness of about 0 mm and a thickness of about 2 cylinders, and the resin was well impregnated between the filaments, and the filaments were uniformly dispersed.

A test piece with a width of 20 and a length of 150 m was cut out from this fiber reinforced resin sheet 6 for thermoforming, and a three-point bending test was conducted at a distance between fulcrums of 120 in accordance with JIS K7203 to measure the bending strength. Further, a No. 1 A test piece was cut out from the thermoforming fiber reinforced resin sheet 6, and its Izot impact strength was measured in accordance with JIS K 7110. Bending strength is 8
．． 6 kg/rMfn2, Izotsu impact strength is 20k
g-cm/cm2.

In addition, the above fiber reinforced resin sheet 6 for thermoforming was heated to 5Kw.
, high-frequency electromagnetic induction heating was performed by applying high-frequency waves of 10 MHz for 15 seconds, and this was heated to a diameter of 12 cm and a depth of 5.
It was vacuum formed into the shape of a cm cup.

In this case, the sheet 6 could be well formed into the above-mentioned tip shape, and had good surface properties without surface irregularities such as raised glass fibers.

Likelihood: Thermoplastic resin powder containing magnetic powder 2, polyvinyl chloride resin (average degree of polymerization 400, average particle size 150μ)
m) 100 parts by weight, and 3 parts by weight of butyltin maleate;
1 part by weight of stearyl alcohol, 0.3 part by weight of polyethylene wax, and iron powder as magnetic powder (average particle size: 80
μm) and 20 parts by weight were uniformly mixed in a super mixer.

In addition, as the thermoplastic resin sheet 4 containing no magnetic powder, polyvinyl chloride resin (average degree of polymerization 1050) 10
0 parts by weight, 3 parts by weight of butyltin maleate, 1 part by weight of stearyl alcohol, and 0.3 parts by weight of polyethylene wax.
Polyvinyl chloride resin sheet (width 450
mm, thickness 1 mm) was used.

Furthermore, when forming the sheet 6, high-frequency electromagnetic induction heating was performed by applying high-frequency waves of 5 Kw and 1 pulse for 20 seconds.

Other than that, the same procedure as in Example 1 was carried out. Obtained sheet 6
is a sheet in which the resin is well impregnated between the filaments and the filaments are uniformly dispersed, and the bending strength is 12,5.
kg/mm”, Izotsu impact strength is 31k
g-am/cm". Further, the sheet 6 could be well formed into a chip shape, and had good surface properties with no surface irregularities such as raised glass fibers.

As thermoplastic resin powder 2 containing magnetic powder, polyvinyl chloride resin (average degree of polymerization 800, average particle size 150 μl)
1 l) 100 parts by weight, 3 parts by weight of butyltin maleate, 3 parts by weight of dioctyl phthalate, 0.3 parts by weight of polyethylene wax, iron powder as magnetic powder (average particle size 8
0 μm) and 20 parts by weight were uniformly mixed in a super mixer.

In addition, as the thermoplastic resin sheet 4 containing no magnetic powder, 100 parts by weight of polyvinyl chloride resin (average degree of polymerization 800, average particle size 150 am), 3 parts by weight of butyltin maleinate, and 3 parts by weight of dioctyl phthalate were used. A polyvinyl chloride resin sheet (width: 450 mm, thickness: 1 mm) consisting of 1.5 parts by weight and 0.3 parts by weight of polyethylene wax was used.

Further, when forming the sheet 6, high-frequency electromagnetic induction heating was performed by applying a high-frequency wave of 5 Kw, IOM) (z) for 20 seconds.

Other than that, the same procedure as in Example 1 was carried out. Obtained sheet 6
was a sheet in which resin was well impregnated between the filaments and the filaments were uniformly dispersed, and the Toro could be well formed into the shape of kelp, and it had good surface properties without surface irregularities such as raised glass fibers. .

100 parts by weight of nylon 12 (average particle size 180 μffl) was used as the thermoplastic resin powder 2 containing Royo magnetic powder, and carbon black (average particle size 30 μm) was used as the magnetic powder.
) and 20 parts by weight were used.

In addition, as the thermoplastic resin sheet 4 that does not contain magnetic powder, a resin sheet of nylon 12 (width: 450 mm) is used.
A laminate 5 was obtained by using a laminate (IIIfi, thickness im) and setting the hot air temperature of the heating furnace to about 200°C.

Further, when forming the sheet 6, high frequency electromagnetic induction heating was performed by applying high frequency waves of 5 km and 10 MHz for 20 seconds.

Other than that, the same procedure as in Example 1 was carried out. Obtained sheet 6
is a sheet in which the resin is well impregnated between the filaments and the filaments are uniformly dispersed, and the bending strength is 13,8
kg/mm”, Izotsu impact strength is 36k
g-cm/cm2. Further, the sheet 6 could be well formed into a chip shape, and had good surface properties without surface irregularities such as raised glass fibers.

100 parts by weight of polyvinylidene fluoride (average particle size 1!10 μm) was used as the thermoplastic resin powder 2 containing the magnetic powder, and 20 parts by weight of fibrous aluminum (fiber length about 100 μm) was used as the magnetic powder. A homogeneous mixture of parts by weight was used.

In addition, the same polyvinylidene fluoride resin sheet (width: 450 mm, thickness: 1 mm) as described above was used as the thermoplastic resin sheet 4 that does not contain magnetic powder, and the hot air temperature of the heating furnace was set to approximately 220°C, and the laminate 5 I got it.

Further, when forming the sheet 6, high frequency electromagnetic induction heating was performed by applying 5 Kiv, 10 MHz high frequency for 20 seconds.

Other than that, the same procedure as in Example 1 was carried out. The obtained sheet 6 is a sheet in which the resin is well impregnated between the filaments and the filaments are uniformly dispersed, and the bending strength is Io, 8.
kg/mm”, Izosod impact strength is 27-cm
/cm2. Further, the sheet 6 could be well formed into a chip shape, and had good surface properties without surface irregularities such as raised glass fibers.

In Example 1, thermoplastic resin powder 2 containing no magnetic powder (iron powder) was used instead of thermoplastic resin powder 2 containing magnetic material. Furthermore, instead of high-frequency electromagnetic induction heating, heating was performed using a far-infrared heater. Other than that, the same procedure as in Example 1 was carried out.

In this case, when the obtained sheet 6 was heated to a relatively high temperature, it could be well formed into the shape of a pot, but since the surface layer of the sheet 6 was heated to a higher temperature than the inner layer, the surface roughness caused by the embossment of the glass fibers. became worse. When the heating temperature of the sheet 6 was lowered in order to improve the surface properties, the sheet 6 cracked during being formed into the shape of a tip, and the sheet 6 was not formed into a perfect shape of a tip.

Comparative Cell In Example 2, the thermoplastic resin sheet 4 containing no magnetic powder was not used at all. Other than that, the same procedure as in Example 2 was carried out.

In this case, the obtained sheet 6 was heated to a relatively high temperature and could be well formed into a pot shape, but the surface properties were deteriorated due to the embossment of the glass fibers. In order to improve the surface quality, the heating temperature of the sheet 6 was lowered by changing the high-frequency electromagnetic induction heating conditions (this caused the sheet 6 to tear while being formed into the shape of a kotsupu, resulting in a complete kotsupu shape. Not molded.

Upper ball 1 In Example 2, heating was performed using a far-infrared heater instead of high-frequency electromagnetic induction heating.

Other than that, the same procedure as in Example 3 was carried out.

In this case, when the obtained sheet 6 was heated to a relatively high temperature, it could be well formed into the shape of a pot, but since the surface layer of the sheet 6 was heated to a higher temperature than the inner layer, the surface roughness caused by the embossment of the glass fibers. became worse. When the heating temperature of the sheet 6 was lowered to improve the surface properties, tears occurred in the sheet 6 while it was being formed into the shape of kelp, and the sheet 6 was not formed into the perfect shape of kelp.

Comparison ↓ In Example 4, the thermoplastic resin sheet 4 containing no magnetic powder was not used at all. Other than that, the same procedure as in Example 4 was carried out.

In this case, the obtained sheet 6 was heated to a relatively high temperature and could be well formed into a pot shape, but the surface properties were deteriorated due to the embossment of the glass fibers. In order to improve the surface properties, high frequency type [If the heating temperature of the sheet 6 was lowered by changing the induction heating conditions, tears would occur in the sheet 6 while it was being formed into the shape of a kelp, resulting in the shape of a perfect kelp. Not molded.

In Example 5, heating was performed using a far-infrared heater instead of high-frequency electromagnetic induction heating.

Other than that, the same procedure as in Example 4 was carried out.

In this case, when the obtained sheet 6 was heated to a relatively high temperature, it could be well formed into the shape of kelp, but since the surface layer of the sheet 6 was heated to a higher temperature than the inner layer, the surface roughness caused by the embossment of the glass fibers. became worse. When the heating temperature of the sheet 6 was lowered in order to improve the surface properties, the sheet 6 cracked during being formed into the shape of a tip, and the sheet 6 was not formed into a perfect shape of a tip.

(Effects of the invention) As mentioned above, the thermoformable fiber reinforced resin sheet of the present invention has the following properties:
It has a good surface condition with no reinforcing fibers protruding onto the surface, and can be suitably used as a so-called stampable sheet, which is a material for press molding to obtain various products.

Furthermore, according to the manufacturing method of the present invention, the reinforcing fibers are well dispersed in monofilament units, and the reinforcing fibers are sufficiently impregnated with resin even between the monofilaments, so that the reinforcing fibers have a high reinforcing effect and have excellent physical properties. A fiber-reinforced resin sheet for thermoforming is obtained.

Furthermore, according to the molding method of the present invention, the fiber-reinforced resin sheet for thermoforming is heated in a short time, and various products with good surface conditions without the reinforcement fibers bulging out on the surface can be produced with good formability. You can get it easily.

[Brief explanation of drawings]

FIG. 1 is a schematic side view showing an example of an apparatus used in the method for producing a thermoformable fiber-reinforced resin sheet of the present invention, and FIG. 2 is a schematic sectional view showing an example of a thermoformable fiber-reinforced resin sheet of the present invention. FIG. 3 is a schematic cross-sectional view showing an example of a conventional fiber-reinforced resin sheet for thermoforming. DESCRIPTION OF SYMBOLS 1... Reinforcing fiber bundle, 1"... Reinforcing fiber, 2... Thermoplastic resin powder, 2"... Magnetic powder, 2a... Fluidized bed of resin powder, 3... aggregate, 4... thermoplastic resin sheet containing no magnetic powder, 5... laminate, 50.
... Cutter roll, 6 ... Fiber-reinforced resin sheet for aging molds, 60, 61 ... A pair of upper and lower endless belts, 80.
... Cooling means. 70... heating means,

Claims (1)

[Claims] 1. A thermoplastic resin sheet containing no magnetic powder is laminated and bonded on at least one side of a fiber-reinforced thermoplastic resin sheet containing particle-like or fibrous magnetic powder. Fiber-reinforced resin sheet for thermoforming. 2. A reinforcing fiber bundle composed of a large number of continuous monofilaments is passed through fluidized thermoplastic resin powder containing magnetic powder, and the resin powder is attached to the monofilaments of this fiber bundle. The fiber bundle to which the resin powder has adhered is cut to a desired length, and while it is dropped onto an endless belt and accumulated, a thermoplastic resin sheet that does not contain magnetic powder is overlaid on at least one side of the aggregate. Combine,
A method for producing a fiber-reinforced resin sheet for thermoforming, which comprises passing through a heating region and a cooling region while sandwiching and conveying the sheet between a pair of upper and lower endless belts. 3. A method for molding a thermoforming fiber reinforced resin sheet, which comprises heating the thermoforming fiber reinforced resin sheet according to claim 1 by high frequency electromagnetic induction heating and molding it into an irregular shape.