JP3027540B2 - Manufacturing method of long fiber reinforced thermoplastic resin composite - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a long fiber reinforced thermoplastic resin composite material having improved thermoplastic resin impregnation, which is a molding material for FRTP (fiber reinforced thermoplastic resin).

[0002]

2. Description of the Related Art FRTP (fiber reinforced thermoplastic resin) reinforced with continuous long fibers is made of general FRP reinforced with short fibers.
It has better mechanical properties than RTP, and has recently been used actively.

[0003] The long fiber reinforced thermoplastic resin composite material is generally produced by a pultrusion method in which a continuous fiber bundle is drawn into a molten thermoplastic resin and drawn through a die. Used by cutting. The long fiber reinforced thermoplastic resin composite material needs to sufficiently and uniformly impregnate the continuous fiber bundle with the thermoplastic resin in order to sufficiently exhibit the mechanical properties and also in view of appearance and workability.

[0004] As one of the methods for improving the impregnating property of a resin, a method of impregnating a continuous fiber bundle with a resin after performing a fiber opening treatment is known, and various methods of the fiber opening treatment are performed. ing. For example, a method of opening with a tension bar or a roll, a method of opening by utilizing repulsion between fibers due to static electricity, a method of blowing with an air jet or a water jet, and the like are used.

[0005] On the other hand, Japanese Patent Application Laid-Open No. 7-216104 discloses the production of a long fiber reinforced resin structure in which a continuous fiber bundle is opened in a fiber opening step, and then a molten resin is impregnated in the continuous fiber bundle in an impregnation step. In the method, there is disclosed a method for producing a long fiber reinforced resin structure, wherein an opening index S defined by the following mathematical formula 2 of the opened continuous fiber bundle is in a range of 2.0 to 18.0.

[0006]

S = 5 × ¹⁰⁻² · (T / L) · (1 / R) (where T represents the number of tex of the continuous fiber bundle, and R represents the fiber diameter (μm) of the continuous fiber. , L is the width of the continuous fiber bundle (c
m). )

[0007]

However, according to the study of the present inventors, within the range of the above-mentioned fiber opening index described in JP-A-7-216104, the impregnating property of the resin is not yet sufficient. I understand. For this reason, it was examined to further increase the degree of spreading, but in that case, the conventional spreading method had the following problems.

That is, in the method using a tension bar or a roll, it is necessary to increase the number of passages or increase the tension, which causes a large damage to the continuous fiber bundle, causes a filament breakage, etc., and deteriorates workability. In addition, there has been a problem that when a long fiber reinforced thermoplastic resin composite material is used, the strength is reduced. Further, it has been proposed to increase the opening effect by making the surface shape of the tension bar or the roll into a Tyco shape, but in that case, there was a problem that the opening of the continuous fiber bundle was biased.

In the method using static electricity,
There has been a problem that the opening direction is two-dimensional and it is difficult to handle. Furthermore, the method using an air jet has a problem that it is difficult to obtain a uniform gas flow, and therefore it is difficult to uniformly open the fiber. Furthermore, the method using a water jet has a problem that a step of removing water is required.

The present invention has been made in view of the above problems, and has as its object to provide a long fiber reinforced thermoplastic resin composite which can sufficiently exhibit mechanical properties by impregnating a resin sufficiently and uniformly. It is to provide a method for manufacturing a material.

[0011]

In order to achieve the above object, the present invention provides a non-twisted continuous fiber bundle having an average flow rate of 10 to 10.
In a gas flowing at 50 m / sec,
And introduced in a direction substantially perpendicular to the gas flow
When doing, per 10mm length along the passing direction
1 to 50 mm to give a sag and open the fiber
And the opening index F defined by the following formula 1 is 0.5 to 3
A method for producing a continuous fiber reinforced thermoplastic resin composite material, comprising: obtaining a continuous fiber bundle of spread fiber obtained as described above; and impregnating the continuous fiber bundle of spread fiber with a thermoplastic resin.

[0012]

F = W / DN (where F is the opening index, W is the width (mm) of the continuous fiber bundle,
D represents the diameter (mm) of the continuous fiber monofilament, N represents the number of continuous fiber monofilaments, and the width of the continuous fiber bundle is
The wound yarn is measured in a tangible state, and the yarn immediately after the opening processing is measured in a state at the outlet of the processing apparatus. )

In the present invention, the fiber opening index F is defined by the above formula 3, and hereinafter, only the fiber opening index will be described.

[0014]

[0015] The long fiber reinforced thermoplastic resin composite material of the present invention
According to the manufacturing method, the untwisted continuous fiber bundle is opened.
Easy to open, and industrially easy to open
The fiber can be spread so as to be 0.5 to 3. Also,
Since the opened continuous fiber bundle having the opening index is impregnated with the thermoplastic resin, the thermoplastic resin is sufficiently and uniformly impregnated. Therefore, F having excellent mechanical properties and excellent appearance
A long fiber reinforced thermoplastic resin composite material from which an RTP molded product can be obtained can be obtained with good workability.

Although the principle of the above-mentioned fiber opening treatment method is not yet well understood, the continuous fiber bundle is moved outward by a pressure difference generated due to a difference in gas flow rate between the center and both ends in the width direction of the continuous fiber bundle. It is thought that it spreads and spreads.
In addition, according to this method, since there is no damage such as filament breakage, the strength does not decrease when a long fiber reinforced thermoplastic resin composite material is used, and it is necessary to remove water and the like used for fiber opening. Nor.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the fibers constituting a continuous fiber bundle include, for example, one or a mixture of two or more selected from glass fibers, carbon fibers, ceramic fibers, metal fibers, and aramid fibers. Although it can be used, it is preferable to use glass fiber from the viewpoint of physical properties, price, and the like. In addition, these fibers may be subjected to a surface treatment in order to enhance wettability and adhesiveness with a thermoplastic resin serving as a matrix.

The number of continuous fiber bundles to be bundled is preferably about 400 to 4000 in consideration of handleability and the like. In the case of a glass fiber bundle, a strand is preferably used,
Roving such as single-ended roving may be used. In addition, a continuous fiber bundle is substantially non-twisted. Twisted fibers are not preferable because they are not sufficiently opened when subjected to the opening process.

The thermoplastic resin used in the present invention includes F
As the matrix of RTP, those generally used can be used, for example, polyethylene, polyolefin resins such as polypropylene, polyamide resins such as nylon 6, nylon 6,6, polyethylene terephthalate, polyester resins such as polybutylene terephthalate, Other thermoplastic resins such as polycarbonate and polyacetal, or modified products thereof can be used alone or in combination. Also, the thermoplastic resin may be added with general additives such as an antioxidant, an antistatic agent, a flame retardant, a lubricant, a release agent, a plasticizer, a coloring agent, and a filler as necessary. Good.

The fiber content of the long-fiber-reinforced thermoplastic resin composite material of the present invention is not particularly limited, but is preferably from 8 to 85% by volume, from the viewpoint of the reinforcing effect and physical properties, and is preferably from 15 to 85% by volume.
75% by volume is more preferred.

FIGS. 1 and 2 show an example of a manufacturing apparatus for carrying out the present invention. FIG. 1 is a schematic side view of the manufacturing apparatus, and FIG. 2 is a schematic plan view of a fiber opening apparatus in the manufacturing apparatus.

1 and 2, reference numeral 11 denotes a continuous fiber bundle 12;
a is a wound roll of cake, 13 is a drive roll for drawing out the continuous fiber bundle 12a, 14 is a fiber opening device that forms a gas flow by a suction method, 15 is a die for impregnating the continuous fiber bundle with resin, Reference numeral 16 denotes a take-off device for taking out a continuous fiber bundle impregnated with a resin, and 17 denotes a pelletizer for pelletizing the obtained long fiber reinforced thermoplastic resin composite material.

According to this manufacturing apparatus, the continuous fiber bundles 12a are respectively pulled out from the outside while rotating the cake 11 of a plurality of continuous fiber bundles, and supplied to the fiber opening device 14 via the driving rolls 13. You. The continuous fiber bundle 12
The reason why a is pulled out from the outside while rotating the continuous fiber bundle cake 11 is to prevent the continuous fiber bundle 12a from being twisted.

The opening device 14 forms a gas flow flowing in the direction of arrow A at an average flow velocity of 10 to 50 m / sec by, for example, suction means. The continuous fiber bundle 12a is introduced from a direction substantially perpendicular to the gas flow, and passes through the gas flow while being given a sag A so as to sag 1 to 50 mm per 10 mm in length in the passing direction. I do. Then, the continuous fiber bundle 12a is subjected to fiber opening processing while passing through the above gas stream, and an open fiber continuous fiber bundle 12b having a fiber opening index defined by the equation (3) of 0.5 to 3 is obtained.

Next, the opened continuous fiber bundle 12b is introduced into a die 15 to which a thermoplastic resin is supplied from a melt extruder (not shown) via a supply pipe 15a, and is impregnated with the thermoplastic resin. The long fiber reinforced thermoplastic resin composite material thus obtained is taken out by the take-up device 16 and the pelletizer 1
7. Cut to desired size and pelletize.

In the fiber opening device 14, any gas may be used as long as it is a safe gas such as air or an inert gas, but it is necessary that the gas flow at an average flow velocity of 10 to 50 m / sec. When the average velocity of the gas is less than 10 m / sec, it takes time until the continuous fiber bundle 12a is sufficiently opened, or when the gas is not sufficiently opened, and when it exceeds 50 m / sec, the continuous fiber bundle 12a is formed. This is not preferable because the filaments that are cut tend to break.

The slack A of the continuous fiber bundle 12a is set so as to sag 1 to 50 mm per 10 mm length along the passing direction. If the slack amount per 10 mm length is less than 1 mm, the fiber is not sufficiently opened, and if it exceeds 50 mm, excessive vibration occurs in the continuous fiber bundle 12a. Bundles 12a, 12a
.. Are simultaneously unparalleled because they are likely to be damaged by contact with the adjacent continuous fiber bundle 12a.

The opening index of the continuous fiber bundle 12b subjected to the opening processing is set to 0.5 to 3, preferably 0.5 to 2. When the fiber opening index is less than 0.5, the fiber opening is insufficient and the impregnating property of the thermoplastic resin is deteriorated, and the resin pressure must be increased to sufficiently impregnate the thermoplastic resin. This causes damage to the fine continuous fiber bundle 12b. On the other hand, if the fiber opening index exceeds 3, it becomes difficult to handle the continuous fiber bundle 12b after fiber opening.

[0029]

[0030] Note that before the introduction of the continuous fiber bundle 12a to the opening device 14 of FIGS. 1 and 2, sends a continuous fiber bundle into the tubular passage
While blowing compressed air into this passage,
The method of opening the fiber by air flow and the continuous fiber bundle
Curve between tension bars and pull to open
The pre-spreading may be performed by a conventional method such as a method within a range that does not damage the continuous fiber bundle 12a.

Further, a method for producing a long fiber-reinforced thermoplastic resin composite material to spread tow 12b was impregnated with a thermoplastic resin is not limited to the above method, it is possible to employ other methods. For example, the opened continuous fiber bundle 12b is
After sandwiching between two thermoplastic resin films or nonwoven fabrics, a tape or sheet-like long fiber reinforced thermoplastic resin composite material may be passed through a heated roll press, a heated calendar or the like. In addition, the spread continuous fiber bundle 12b
Into a solution or emulsion obtained by adding a solvent to a thermoplastic resin, dried through a heating furnace and melted the thermoplastic resin, and then passed through a shaping nozzle to form a tape, sheet, or rod-shaped long fiber reinforced heat. A method of forming a plastic resin composite material may be employed.

The obtained long fiber reinforced thermoplastic resin composite material can be used as it is in the form of a tape, sheet, or rod, and cut into a predetermined length with a pelletizer or the like as described above. May be.

The long fiber reinforced thermoplastic resin composite material of the present invention can be used for molded articles in a wide range of fields, such as automobiles, housings and casings of electric and electronic parts, and general goods.

[0034]

【Example】

Example 1 As a continuous fiber bundle, a filament having a fiber diameter of 16 μm was 4000
Using this bundled glass fiber roving, average flow rate of 40
When passing through the air flow from a direction substantially perpendicular to the air flow direction into the air flow flowing at m / sec, the length along the passing direction is 60 mm for 30 mm (20 mm for 10 mm) )
It was introduced while giving a slack so that the fiber was opened. The width of the opened glass fiber strand was 77 mm, and the opening index was 1.2.

Next, the obtained opened fiber glass strand is drawn into a die to which molten polypropylene is supplied while maintaining the width thereof, and impregnated with polypropylene. 45% by volume
I got a rod.

Next, the obtained rod was passed through a cooling bath, taken up by a take-up machine, and cut into a length of 6 mm with a pelletizer to obtain pellets of a long fiber reinforced thermoplastic resin composite material.

Example 2 In Example 1, the average air velocity was changed to 20 m / sec.
Thereafter, in the same manner as in Example 1, an opened glass fiber strand having a width of 39 mm and an opening index of 0.6 was obtained.

The obtained opened fiber glass strand was formed into a rod in the same manner as in Example 1, and then into a pellet.

Comparative Example The same glass fiber roving as in Example 1 was spread using a roll bar to obtain a spread glass fiber strand having a width of 10 mm and a fiber opening index of 0.15.

The obtained opened fiber glass strand was formed into a rod in the same manner as in Example 1, and then into a pellet.

Test Example The pellets obtained in Examples 1 and 2 and Comparative Example were diluted with polypropylene so as to have a glass content of 15% by volume, and directly injection-molded into test pieces to obtain a strength according to ASTM. A test was performed to measure the tensile strength and the bending strength. Further, a flat plate of 100 × 100 × 2.5 mm was formed, and the number of undispersed glass fiber strands was counted visually. Table 1 shows the results.

[0042]

[Table 1]

From the results shown in Table 1, the long fiber reinforced thermoplastic resin composite materials of Examples 1 and 2 in which the opening index was set to 1.2 and 0.6 were the long fiber reinforced thermoplastic resins of Comparative Examples having an opening index as low as 0.15. It can be seen that the number of undispersed glass fiber strands is much smaller than that of the composite material, and that both the tensile strength and the bending strength are excellent. In addition, in the comparison between Examples 1 and 2, it can be seen that the higher the fiber opening index, the greater these effects.

[0044]

As described above, according to the present invention,
Workability without damaging the continuous fiber bundle
The fiber can be spread so that the spread index is 0.5-3.
Can, by impregnating a thermoplastic resin into a continuous fiber bundle is thus increased opening, Ru can be a thermoplastic resin to obtain a sufficient and evenly impregnated long fiber-reinforced thermoplastic resin composite material. Then, by using this composite material can be further improved mechanical properties and appearance of the molded article.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing an example of a manufacturing apparatus for carrying out the present invention.

FIG. 2 is a schematic plan view of a fiber opening device used in the manufacturing apparatus.

[Explanation of symbols]

 Reference Signs List 11 cake of continuous fiber bundle 12a continuous fiber bundle 12b spread continuous fiber bundle 13 drive roll 14 fiber opening device 15 die 16 take-off device 17 pelletizer A deflection of continuous fiber bundle

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B29B 15/08-15/14 B29B 11/16 C08J 5/24

Claims (1)

(57) [Claims] 1. An untwisted continuous fiber bundle is produced at an average flow rate of 10 to 10.
In a gas flowing at 50 m / sec,
And introduced in a direction substantially perpendicular to the gas flow
When doing, per 10mm length along the passing direction
1 to 50 mm to give a sag and open the fiber
Subjected, after obtaining the opening continuous fiber bundle open繊指number F, which is defined by the following Equation 1 is as 0.5-3, long fibers, characterized in that impregnating the thermoplastic resin in the opening tow A method for producing a reinforced thermoplastic composite material. F = W / DN (where F is the opening index, W is the width of the continuous fiber bundle (m
m), D is the diameter of continuous fiber monofilament (mm), N
Represents the number of continuous fiber monofilaments, and the width of the continuous fiber bundle is measured in a tangible state in the wound yarn, and the width immediately after the opening processing is measured in a state at the outlet of the processing apparatus. )