JP3288302B2 - Continuous fiber reinforced thermoplastic prepreg sheet and molded product thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous fiber reinforced thermoplastic prepreg sheet made of a thermoplastic resin composite glass fiber fiber material obtained by impregnating a glass fiber with a thermoplastic resin, and a molded product thereof.

[0002]

2. Description of the Related Art Conventionally, thermoplastic resin prepreg sheets comprising continuous reinforcing fibers and a thermoplastic resin have been used because of their high productivity and excellent recyclability compared to thermosetting resin prepreg sheets. It is widely used as a molding material for reinforced thermoplastic resin (FRTP).

[0003] This thermoplastic resin prepreg sheet is a non-woven fabric obtained by adhering a thermoplastic resin as a powder, a fiber, or a film to a continuous reinforcing fiber aligned in one direction from the bonding state of the continuous reinforcing fiber and the thermoplastic resin. It is classified into two types, a consolidated type and a consolidated type in which a continuous reinforcing fiber is impregnated with a molten resin.

A non-consolidated type prepreg sheet has good adhesiveness (tackiness), shapeability, and mold conformability at the time of secondary processing. There is a problem that a formed body having many voids is likely to be formed due to subsequent processing, and it is difficult to obtain a good formed body. In addition, it is possible to pass a non-consolidated type material through a pultrusion mold or the like to make it consolidated, but in this case, the number of steps is increased and there is a problem in workability.

[0005] On the other hand, the consolidated prepreg generally has a good bonding state between the continuous reinforcing fiber and the thermoplastic resin, but has a high rigidity and is inferior in flexibility and adhesiveness. There was a problem that good shapeability and mold conformability could not be obtained during the subsequent processing.

To solve these problems, Japanese Patent Laid-Open No.
Japanese Patent Application Laid-Open No. 206206/1990 discloses a consolidated tape-shaped tow prepreg in which a thermoplastic resin is impregnated into a single tow of a continuous reinforcing fiber. A prepreg sheet of a woven fabric using the other as a weft has been proposed.

[0007]

However, in the above prior art, since the tow prepreg constituting the prepreg sheet is in a tape shape, the tow prepreg itself has a flexibility perpendicular to its width direction. In the direction, the flexibility was poor. That is, in the prepreg sheet employing this tow prepreg, it is possible to obtain a flexibility perpendicular to the width direction of the sheet, but the flexibility in the surface direction of the sheet is inferior, and furthermore, the longitudinal direction of the sheet and Regarding the parallel flexibility, although the arranged toe prepregs have flexibility at their joints, there is a limit in obtaining sufficient flexibility because the tow prepreg is wide.

For this reason, the prepreg sheet still has poor shapeability and mold conformability during secondary processing,
There was a problem that workability was inferior. In addition, since the tow prepreg is in the form of a tape having a flat surface and a large surface area, if the content of the reinforcing fibers is too large, the coating of the resin on the continuous reinforcing fibers becomes insufficient, and a molded article having good physical properties cannot be obtained. Had the problem that

[0009] Accordingly, an object of the present invention is to provide a prepreg sheet having excellent flexibility and flexibility in multiple directions, and having good shaping properties, mold conformability and adhesiveness during secondary processing, and molded articles thereof. Is to provide.

[0010]

Means for Solving the Problems To achieve the above object, one of the present invention is a thermoplastic resin composite glass fiber fiber material in which a glass fiber strand is impregnated with a thermoplastic resin, and a thermoplastic resin fiber. And a continuous fiber reinforced thermoplastic prepreg sheet formed by weaving the thermoplastic resin composite glass fiber fiber material, wherein a plurality of glass monofilaments are used.
Single glass fiber bundled without splitting
Weave strand impregnated with thermoplastic resin, average diameter
1.5 mm or less, having a substantially circular or elliptical cross section, a glass content of 25 to 80 vol%, and a buckling limit at the time of bending expressed by a curvature;
30D × V (D = average diameter, V = glass content: vol%
/ 100, the unit of R and D is mm), and provides a continuous fiber reinforced thermoplastic prepreg sheet.

[0011] In the continuous fiber-reinforced thermoplastic prepreg sheet of the present invention is preferably a thermoplastic resin impregnation ratio of the thermoplastic resin composite glass fiber-woven is 95% or more.

Further, the glass fiber strand may be 200
It consists of a bundle of ~ 2000 glass monofilaments, and the average diameter of the glass monofilament is 6 ~
It is preferably 17 μm.

Further, it is preferable that the thermoplastic resin impregnated in the glass fiber strand and the thermoplastic resin fiber are the same or compatible resins.

It is preferable that a plurality of the prepreg sheets are laminated and temporarily fixed.

Further, it is preferable that the prepreg sheet has a glass content of 15 to 75 vol%.

Another object of the present invention is to provide a continuous fiber reinforced thermoplastic prepreg sheet formed by laminating the continuous fiber reinforced thermoplastic prepreg sheet alone or by laminating a plurality thereof.

The continuous fiber reinforced thermoplastic prepreg sheet molded article is obtained by combining the continuous fiber reinforced thermoplastic prepreg sheet and a thermoplastic resin film, and preferably has a glass content of 15 to 75 vol%.

According to the present invention, a thermoplastic resin composite glass fiber fiber material comprises a plurality of glass monofilaments.
Single glass fiber strand bundled without applying
With a thermoplastic resin impregnated with an average diameter of 1.5 mm
It has a substantially circular or elliptical cross section, and when the buckling limit when bent is represented by curvature, the curvature R
≦ 30D × V (D = average diameter, V = glass content: vol
% / 100, and the units of R and D are mm), so that the flexibility is excellent in multiple directions. For this reason, the continuous fiber reinforced thermoplastic prepreg sheet of the present invention formed by weaving the thermoplastic resin composite glass fiber fiber material and the thermoplastic resin fiber has excellent flexibility and shapeability during secondary processing. Good mold conformability and adhesiveness.

Further, the prepreg sheet of the present invention can increase the glass content of the thermoplastic resin composite glass fiber material to 80%, so that the strength of the molded article can be improved and the thermoplastic resin By adjusting the fiber content, the glass content can be set widely, and a molded article having a desired strength can be obtained.

Further, the thermoplastic resin composite glass fiber fiber used in the present invention has a good bonding state between the glass fiber and the thermoplastic resin and an extremely high resin impregnation rate. Even if a thermoplastic resin fiber is combined with a material and the thermoplastic resin composite glass fiber fiber material and the thermoplastic tree fiber are integrated, rapid molding can be performed at a low pressure. Moreover, the obtained molded article has a uniform distribution of glass fibers in the molded article, and has almost no voids.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The continuous fiber reinforced thermoplastic prepreg sheet (hereinafter referred to as prepreg sheet) of the present invention comprises:
It consists of a woven fabric of a thermoplastic resin composite glass fiber fiber material (hereinafter, referred to as a composite fiber material) and a thermoplastic resin fiber.

The composite fiber material is formed by impregnating a glass fiber strand in which a plurality of glass monofilaments are bundled with a thermoplastic resin.

The thermoplastic resin is not particularly limited, and various commercially available resins can be used. In particular, polyolefin-based resins and polyamide-based resins can be used in view of impregnation into glass fibers, cost, and physical properties. It is suitable. Among the polyolefin resins, polypropylene is preferable, and among the polyamide resins, nylon 6.6, nylon 6, nylon 12, and MXD nylon are particularly preferable. These resins may be mixed with additives such as colorants, modifiers, antioxidants and the like.

The glass fiber strand has an average diameter of 6-1.
It is preferably made of a glass monofilament having a diameter of 7 μm.
The number is preferably 2,000, more preferably 200 to 1600. If the number of bundles is less than 200, a large number of composite fibers are required in the post-process, and the operation becomes complicated. On the other hand, if it exceeds 2,000, the glass fiber strands become thicker, so that it is not easy to impregnate the thermoplastic resin uniformly between the monofilaments,
The resulting composite fiber also becomes thicker and less flexible.

As the glass fiber strand, it is preferable to use a bundle of a plurality of glass monofilaments without splitting. Here, the term "split" means that when a large number of monofilaments drawn from a glass melting furnace are bundled, they are divided into a plurality of glass fiber strands by a splitter and then bundled.

As shown in FIG. 2 (a), when a plurality of glass fiber strands are aligned or split glass fiber strands are used, the lengths of the individual strands are not uniform and are partially increased. S1 and the like easily occur. When such a strand S is pulled out through the nozzle N, as shown in FIG. 4B, the elongated piece S1 is squeezed by the nozzle N to form a loop, and the glass content is extremely high in part. This causes the fiber to be cut, making it difficult to pull out the nozzle.

Further, as a method of impregnating a glass fiber strand with a thermoplastic resin, the glass fiber strand is fed into a resin impregnation tank, impregnated with the resin by a melt impregnation method, and then one glass fiber strand is inserted into one nozzle. It is preferable to adopt a method of pulling out and winding.

As shown in FIG. 3, for example, when three strands S1 to S3 are passed through the nozzle N, the strands S1 to S3 are flattened at the time of winding on a cake or the like.
The cross section tends to be flat or nearly elliptical. For this reason, as shown in FIG.
3 are arranged in a flat direction, it is easy to pass through the nozzle N. However, if one of the strands S3 is lying down as shown in FIG. , May be difficult to pull out.

In the present invention, as shown in FIGS. 2 and 3, one glass fiber strand obtained by bundling a plurality of glass monofilaments into a split is used as the glass fiber strand for resin impregnation. Problems can be solved, and clogging does not occur when pulling out from the nozzle, and pulling out from the nozzle becomes easy, so that the glass content and the resin impregnation rate can be increased, and an appearance with less fluff can be obtained. .

The composite fiber thus obtained is disclosed in
It does not have a flat and tape-like shape as shown in No. 206223, but has a substantially circular or elliptical cross-section and a wire-like shape such as a cocoon depending on the drawing conditions.

The average diameter of the composite fiber is preferably 1.5 mm or less. More preferably, it is set to 1.0 mm or less. If the average diameter exceeds 1.5 mm, flexibility becomes poor, winding becomes difficult, and it is not suitable for producing a woven fabric or a barbed prepreg sheet. Here, the average diameter is obtained by calculating the average value of the minor axis and the major axis of the cross section from the average of five cross sections arbitrarily selected.

The glass content of the composite fiber is from 25 to 25.
80 vol%, preferably 60 to 80 vol%. If it is less than 25 vol%, the reinforcing effect is low, and 80 v
If it exceeds ol%, the amount of the matrix resin surrounding the fibers is too small, and it is difficult to increase the impregnation rate.

In the composite fiber material, when the buckling limit at the time of bending is represented by the curvature, the curvature R ≦ 30D × V (D
= Average diameter, V = glass content: vol% / 100, and the unit of R and D needs to be mm). Curvature R
The smaller the value, the better the handleability when forming a prepreg sheet, which is preferable. When the curvature R exceeds 30D × V, it is difficult to use as a prepreg sheet because of high rigidity and poor flexibility.

The curvature R is a value measured by the method shown in FIG. That is, first, a test piece (composite fiber material) 10 having a total length of 600 mm and a collar 11 are prepared. A loop 10a is formed by passing both ends of the test piece 10 through the collar 11, and each end 50mm is pulled by a tensile tester chuck 12,
Fix to 13. Then, the chucks 12 and 13 are moved and pulled at a speed of 10 mm / min, the length L of the chuck interval when buckling is measured, the length of the loop 10a is calculated from this length L, and the length of the loop 10a is calculated. The length was divided by 2π to obtain R.

Further, the resin impregnation rate of the composite fiber material is preferably 95% or more. If it is less than this, uniform mechanical properties cannot be obtained, and when formed into a prepreg sheet, voids tend to become defects, which is not preferable.

Here, the impregnation ratio means that the cross section of the composite fiber is 20
Observation with a 0 × electron microscope, a 20 μm mesh was placed. If any voids (bubbles of air) were found in the mesh, this mesh was added as a void area, and the observed total cross-sectional area and void area were calculated. It is obtained by the following formula.

[0037]

[Equation 1] {(total sectional area-void area) / total sectional area} × 1
00 (%) Next, the thermoplastic resin fibers used in the present invention give flexibility to the sheet while maintaining the aligned arrangement of the composite fibers, and are used for shaping during secondary processing. It improves the properties, conformability and adhesiveness, and further improves the surface appearance of the molded article.

As the thermoplastic resin fibers, those which are the same as or compatible with the thermoplastic resin used for the composite fiber material are used. As the form of the thermoplastic resin fiber, a circular cross section composed of a monofilament or a strand,
It is preferable to use an elliptical one or the like.

The prepreg sheet of the present invention is a woven fabric comprising the above-mentioned composite fiber material and the above-mentioned thermoplastic resin fiber. Examples of the woven structure include plain weave, twill weave, satin weave, leno weave, and blind weave. Can be appropriately selected according to the workability at the time of use and the use of the molded article.

The number of the composite fibers and the number of the thermoplastic resin fibers to be imprinted is good because the resulting prepreg sheet has good flexibility regardless of the number of the imprints.
Although not particularly limited, usually, the number of driving of the composite fiber material is increased, and based on this, the number of driving of the thermoplastic resin fiber is set so as to obtain a desired molded product. For example, it is also possible to reduce the number of thermoplastic resin fibers to be driven so as not to disturb the arrangement of the composite fibers aligned in one direction, to increase the glass content, and to drive the thermoplastic resin fibers. By increasing the number, it is possible to improve the adhesiveness during the secondary processing and the surface appearance of the molded article.

The glass content of the prepreg sheet is 15
It is preferably from 75 to 75 vol%, and more preferably from 20 to 70 vol%. If it is less than 15 vol%, the reinforcing effect of the glass fiber is inferior.

The prepreg sheet thus obtained is composed of one sheet. When a plurality of prepreg sheets are laminated at the time of secondary processing to obtain a molded product, the prepreg sheets are laminated in advance, and each layer is formed. It is preferable to use a prepreg sheet that is partially temporarily fixed. Thereby, it is not necessary to laminate a plurality of prepreg sheets at the time of the secondary processing, and it is easy to set the prepreg sheet in a molding die, thereby improving workability.

The method of lamination in this case is not particularly limited, and the lamination is appropriately selected unidirectionally or multiaxially according to the desired molded product. The temporary fixing method is preferably such that each layer is partially fixed so as not to impair the flexibility of the prepreg sheet, and a method such as adhesive, needle processing, stitch processing and the like can be appropriately selected.

The prepreg sheet molded product of the present invention can be obtained by a method of preheating and cooling and pressing the prepreg sheet alone or by laminating the prepreg sheets, or a method of heating and cooling the prepreg sheet.

The prepreg sheet molded article of the present invention is desirably adjusted in glass content in the molded article and has a good surface appearance. Therefore, at least the outermost layer of the prepreg sheet before the secondary processing is performed. It is preferable that a thermoplastic resin film is laminated on one side and subjected to secondary processing.
The resin used for the thermoplastic resin film is preferably the same as or compatible with the resin used for the composite fiber material or the thermoplastic resin fiber.

In this case, the glass content is 15 to 75 v
ol%, more preferably 20 to 7%.
0 vol%. If it is 15 vol% or less, the reinforcing effect of the glass fiber is inferior, and if it is 75 vol% or more, the adhesiveness at the time of secondary processing and the surface appearance of the molded product are not preferable. The molded article obtained by the above molding method has a good surface appearance, few voids, and good physical properties.

[0047]

Example 1 Using a monofilament having an average diameter of 13 μm, a glass fiber strand having a convergence number of 600 without splitting was introduced into an acid-modified molten polypropylene (260 ° C.) having MI = 40. After melt impregnation, it was pulled out from a nozzle having an inner diameter of 0.42 mm at a speed of 50 m / min, and wound up on a bobbin. The composite fiber thus obtained has an average diameter of 0.42 mm and a glass content of 67 vol.
%, And the impregnation rate was 100% as an average value of n = 5.

The glass content was measured by heating the obtained composite fiber in an electric furnace at 600 ° C. to burn off the resin, and then measuring the weight of the remaining glass to obtain a glass content. A measurement of 85 wt% was obtained. From this value, the specific gravity of the resin was set to 0.91, and the specific gravity of the glass fiber was set to 2.54.
Was converted to The curvature R of the composite fiber at the time of buckling measured by the method shown in FIG. 1 is 6.0 mm as an average value of n = 5.
It was excellent in flexibility.

The obtained composite fiber material is made into warp yarns and drawn in one direction. The thermoplastic resin fiber of 75 denier polypropylene resin is used as weft yarns, and the weaving density (number of shots) is 52 warp yarns / 25 mm and 3 weft yarns. / 25 mm, and prepreg sheets were obtained. The obtained prepreg sheet had a glass fiber content of 66.5 vol%, had flexibility, and had good shapeability and mold conformability during secondary processing.

Example 2 The same composite fiber as in Example 1 was used as the warp and 68 as the weft.
Using 0 denier polypropylene resin thermoplastic resin fiber, weaving density 18 warp / 25 mm, weft 1
The woven fabric was plain-woven at 5 pieces / 25 mm to obtain a prepreg sheet having a glass fiber content of 33 vol%. The obtained prepreg sheet had flexibility and had good shapeability, mold conformability, and adhesiveness during secondary processing.

Example 3 The prepreg sheet of Example 2 was multiaxially (adjacent layer was 90
5), and a prepreg sheet was obtained, which was stitched with a polypropylene resin at intervals of 0.5 / cm ² and temporarily fixed. The obtained prepreg sheet was easy to be set in a mold during secondary processing.

Example 4 The prepreg sheet of Example 1 was subjected to multi-axial (adjacent layer was 9
(0 degree direction), and after sandwiching the outermost layer with a polypropylene resin film on the top and bottom,
Press molding was performed at 230 ° C. under a pressure of 4 kg / cm ³ for 1 minute to obtain a flat molded body having a glass fiber content of 40 vol%.

Example 5 The prepreg sheet of Example 2 was multi-axially (adjacent layer was 9
After laminating five sheets (in the direction of 0 °), they were molded in the same manner as in Example 4 to obtain a molded body having a glass fiber content of 33 vol%.

Example 6 The prepreg sheet of Example 3 was molded in the same manner as in Example 5 to obtain a molded article having a glass fiber content of 33 vol%.

COMPARATIVE EXAMPLE 1 Using a monofilament having an average diameter of 13 μm, three glass fiber strands having a convergence number of 600 without splitting were aligned, and an acid-modified molten polypropylene having MI = 40 (260 ° C.) ), Melt impregnated, and then 30 m / mi from a 0.73 mm inner diameter nozzle.
It was pulled out at a speed of n and wound up on a bobbin.

The composite fiber thus obtained had some fluffs on the surface. The average diameter of the obtained composite fiber was 0.73 mm, the glass content was 67 vol% (the measurement method was the same as in Example 1), and the impregnation rate was 94%. The curvature R of the obtained composite fiber at the time of buckling is 16.0 mm.
And it was inferior in flexibility.

The obtained composite fiber material was made into warp yarns and drawn in one direction. The thermoplastic resin fiber of polypropylene resin of 75 denier was used as weft yarns, and the weaving density (number of shots) was 17 warp yarns / 25 mm and 6 weft yarns. / 25 mm, and prepreg sheets were obtained. The obtained prepreg sheet had a content of glass fibers of 66.5 vol%, was inferior in flexibility, and was poor in shapeability, mold conformability, and adhesiveness in secondary processing.

Comparative Example 2 The prepreg sheet obtained in Comparative Example 1 was molded in the same manner as in Example 4 to obtain a molded article.

For the molded articles obtained in Examples 4 to 6 and Comparative Example 2, the presence or absence of voids was confirmed by visually observing the presence or absence of a whitening point due to unimpregnation from a molded piece of 10 cm ² . Further, the surface appearance was confirmed by visually observing whether or not the surface of the glass filament terminal was raised. Table 1 shows the obtained results.

[0060]

[Table 1]

As shown in the above results, the prepreg sheet of the example manufactured using a composite fiber material obtained by pulling out one glass fiber strand without split from one nozzle has three glasses. Compared to the prepreg sheet of the comparative example manufactured using a composite fiber material of the same glass content obtained by pulling a fiber strand from one nozzle, it has excellent flexibility and shapeability and mold conformability during secondary processing And the tackiness was good. Further, the molded body of the example had almost no voids and a good surface appearance as compared with the comparative example.

[0062]

As described above, according to the present invention,
A continuous fiber reinforced thermoplastic prepreg sheet having excellent flexibility in multiple directions, good shapeability, mold conformability, and adhesiveness during secondary processing and capable of rapid molding can be obtained.
Further, the molded product obtained by using this prepreg sheet can have a desired strength, the glass fiber distribution is uniform, there is almost no void, and the surface appearance is excellent.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a method of testing a curvature R.

FIG. 2 is an explanatory view showing a state in which a glass fiber strand is pulled out from a nozzle in a conventional method for producing a thermoplastic resin composite glass fiber fiber material.

FIG. 3 is a schematic view showing a state in which a glass fiber strand enters a nozzle in a conventional method for producing a thermoplastic resin composite glass fiber fiber material.

[Explanation of symbols]

 Reference Signs List 10 Test piece of thermoplastic resin composite glass fiber fiber material 10a Loop 11 Collar 12, 13 Chuck S, S1, S2, S3 Glass fiber strand N Nozzle

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification code FI B29K 105: 06 B29K 105: 08 105: 08 B29L 9:00 B29L 9:00 B29C 67/14 X (56) References JP 4-222243 (JP, A) JP-A-5-169445 (JP, A) JP-A-6-206223 (JP, A) JP-A-3-1199034 (JP, A) JP-A-5-239739 (JP, A) A) JP-A-3-119140 (JP, A) JP-A-9-111577 (JP, A) JP-A-9-67757 (JP, A) JP-A-7-22719 (JP, A) JP-A-5 -78947 (JP, A) JP-A-61-244088 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) D03D 1/00-27/18 B29B 11/16 C08J 5/04 -5/10 C08J 5/24 D02G 1/00-3/48 D02J 1/00-13/00

Claims (8)

(57) [Claims] 1. A continuous fiber-reinforced thermoplastic prepreg sheet formed by weaving a thermoplastic resin composite glass fiber fiber material in which a thermoplastic resin is impregnated into a glass fiber strand, and a thermoplastic resin fiber, Spun multiple glass monofilaments
One glass fiber strap bundled without lit
With a thermoplastic resin impregnated with a mean diameter of 1.5 m
m or less, has a substantially circular or elliptical cross section, a glass content of 25 to 80 vol%, and, when the buckling limit when bent is represented by a curvature, a curvature R ≦ 30D ×
V (D = average diameter, V = glass content: vol% / 10
The unit of 0, R and D is mm), the continuous fiber-reinforced thermoplastic prepreg sheet. 2. The thermoplastic resin composite glass fiber fiber material
The continuous fiber-reinforced thermoplastic prepreg sheet according to claim 1 , wherein the thermoplastic resin impregnation rate is 95% or more . 3. The glass fiber strand according to claim 2, wherein
000 glass monofilaments are bundled, and the average diameter of the glass monofilaments is 6 to 17
The continuous fiber-reinforced thermoplastic prepreg sheet according to claim 1 or 2, which has a particle size of µm. 4. A continuous fiber reinforced thermoplastic prepreg sheet according to the glass fiber thermal impregnated into strands thermoplastic resin and the thermoplastic resin fibers, according to claim 1-3 is a resin having the same or compatible. Wherein said prepreg sheet, are plurally stacked, continuous fiber reinforced thermoplastic prepreg sheet according to any one of claims 1-4 being tacked. 6. Continuous fiber-reinforced thermoplastic prepreg sheet according to any one of claims 1-5 glass content of the prepreg sheet is 15~75vol%. 7. A continuous fiber reinforced thermoplastic prepreg sheet formed by laminating the continuous fiber reinforced thermoplastic prepreg sheet according to any one of claims 1 to 6 alone or by laminating a plurality thereof. 8. The continuous fiber reinforced thermoplastic prepreg sheet molded article according to claim 7, which is obtained by combining the continuous fiber reinforced thermoplastic prepreg sheet and a thermoplastic resin film, and has a glass content of 15 to 75 vol%.