JP3333448B2 - Long fiber glass reinforced thermoplastic resin composite substrate and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a long fiber glass reinforced thermoplastic resin composite substrate in which a long glass fiber is impregnated with a thermoplastic resin, and a method for producing the same.

[0002]

2. Description of the Related Art As a molding material of a fiber-reinforced thermoplastic resin (FRTP), a molding prepreg in which continuous glass fiber is combined with thermoplastic resin fiber or powder is known. However, this prepreg for molding is generally used to impregnate the glass fiber with the resin when the thermoplastic resin is melted and pressed in a later step, so that it is difficult to completely impregnate the glass fiber, and the The drawback is that the rate tends to be non-uniform.

On the other hand, a composite material obtained by impregnating a continuous glass fiber with a thermoplastic resin is a Long Fiber Compound (hereinafter referred to as L).
It is also known as FC), and cuts of this LFC and resin pellets are blended in an appropriate ratio and molded by an injection molding machine to produce FRTP. In this method, since the glass fiber in the LFC is impregnated with the resin in advance, the resin impregnating property at the time of molding is also better than that described above.

As a method of manufacturing an LFC, Japanese Patent Application Laid-Open No. Hei 6-23742 by the present applicant discloses that a plurality of glass fiber strands having a monofilament overlap degree of a predetermined value or less are aligned, fed into a resin impregnation tank, and melted. A method is disclosed in which a resin is impregnated into a glass fiber and then drawn out from a nozzle having a predetermined inner diameter to form the glass fiber.

Further, Japanese Patent Application Laid-Open No.
No. 14830 discloses that a large number of monofilaments drawn from a glass melting furnace are divided and bundled into a plurality of glass fiber strands by a splitter, and the plurality of glass fiber strands are arranged in parallel and wound by a spiral wire. A method is disclosed in which a plurality of glass fiber strands drawn from the obtained wound body (cake) are fed into a resin impregnation tank, and are drawn from a nozzle in the same manner as described above.

[0006]

However, as disclosed in JP-A-6-23742, when a plurality of glass fiber strands are aligned and impregnated with a resin and pulled out from a nozzle, or as disclosed in JP-A-6-114830. As shown in (1), when the split (split) glass fiber strand is impregnated with a resin and pulled out from the nozzle, there are the following problems.

That is, as shown in FIG. 2 (a), a plurality of glass fiber strands or a split (split) glass fiber strand S are partially aligned because the lengths of the individual strands are not uniform. Things that have become longer
Etc. are likely to 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.

As shown in FIG. 3, for example, when three strands S1 to S3 are passed through a nozzle N, each of the strands S1 to S3 is flattened at the time of winding on a cake or the like, and has a flat or cross-sectional shape. It tends to be close to an ellipse.
For this reason, as shown in FIG.
When S3 is aligned in a flat direction, it is easy to pass through the nozzle N. However, if one of the strands S3 lays down as shown in FIG. May be difficult to pull out.

For this reason, according to the conventional method, when trying to increase the glass content, clogging of the glass fiber at the nozzle is apt to occur, and the productivity is reduced. There was a problem that fluff was easily generated.

[0010] Further, the LFC obtained by the conventional method has a large diameter and high rigidity, so that it takes time for heat to be transmitted to the center during injection molding, and the mechanical shearing force near the bottom of the hopper is reduced. There was a problem in that the fiber was strongly received, as a result, the fiber was more broken, the length of the remaining fiber was shortened, and a sufficient reinforcing effect could not be obtained.

Accordingly, it is an object of the present invention to provide a glass having a high glass content, a small amount of fluff on the outer periphery, a flexibility, a long remaining fiber length during injection molding, and a sufficient reinforcing effect. An object of the present invention is to provide a fiberglass-reinforced thermoplastic resin composite substrate and a method for producing the same.

[0012]

In order to achieve the above-mentioned object, a long fiber glass reinforced thermoplastic resin composite substrate according to the present invention comprises a single glass obtained by bundling a plurality of glass monofilaments without applying a split. A long fiber glass reinforced thermoplastic resin composite substrate comprising a fiber strand impregnated with a thermoplastic resin and cut to a predetermined length, A) an average diameter of 1.0 mm or less, and B) a length. C) the glass content is 60 to 80 vol%, D) the impregnation rate of the thermoplastic resin is 95% or more, and E) the crush when bent before cutting. When the bending limit is represented by a curvature, the curvature is characterized by R ≦ 30D × V (D = average diameter, V = glass content: vol% / 100, unit of R and D is mm).

Further, the method for producing a long-fiber glass-reinforced thermoplastic resin composite substrate according to the present invention is characterized in that one glass fiber strand obtained by bundling a plurality of glass monofilaments without splitting is melt-impregnated. The glass fiber strand is impregnated with a thermoplastic resin by a method, and the single glass fiber strand is pulled out from one nozzle and cut. A) The average diameter is 1.0 mm or less, and B) The length is 3 to 100 mm. C) the glass content is 60 to 80 vol%, D) the impregnation rate of the thermoplastic resin is 95% or more, and E) the buckling limit when bent before being cut. The composite base material is characterized by obtaining a composite base material having a curvature R ≦ 30D × V (D = average diameter, V = glass content: vol% / 100, unit of R and D is mm) when represented by:

According to the present invention, one glass fiber strand obtained by bundling without splitting is impregnated with a thermoplastic resin, and then pulled out from one nozzle and cut to obtain a glass content. Even if the height is increased, continuous production is possible by preventing nozzle clogging, and a long fiber glass reinforced thermoplastic resin composite base material with less fluff on the outer periphery, high thermoplastic resin impregnation rate, and excellent flexibility be able to.

The obtained long-fiber glass-reinforced thermoplastic resin composite substrate has the above-mentioned properties A to E, so that it is rich in flexibility, has little breakage during injection molding, and has a low residual fiber content. Since the length is long, an excellent reinforcing effect is obtained. In addition, since the impregnation rate of the thermoplastic resin is high,
The glass content of the molded product is likely to be uniform, and rapid molding at low pressure is possible. Furthermore, since the glass content is high,
By changing the mixing ratio of the composite base material and the thermoplastic resin, it is possible to obtain a molded product having a wide glass content depending on the purpose.

In the present invention, the number of bundles of the glass fiber strands is preferably 200 to 2,000, and the average diameter of the glass monofilament is preferably 6 to 17 μm. By setting the number of bundles of the glass fiber strands and the average diameter of the glass monofilament to the above ranges, it is easier to obtain the one having the above-mentioned properties A to E.

As the thermoplastic resin, a polyolefin resin or a polyamide resin is preferably employed.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The glass fiber strand used in the present invention is obtained by bundling a plurality of glass monofilaments without splitting them. By using one glass fiber strand bundled without applying a split in this way, the state as shown in FIG. 2B due to the irregular length of the strands and the diagram of the positional relationship between the strands The state shown in FIG. 3 (b) does not occur, and clogging does not occur at the time of pulling out from the nozzle, and pulling out from the nozzle becomes easy, so that the glass content can be increased and the amount of fluff is reduced. Appearance can be.

The average diameter of the glass fibers is 6 to 17 μm.
Preferably, the number of convergence is preferably 200 to 2,000, more preferably 200 to 1600. Focusing number is 2
When the number is less than 00, a large number of long fiber glass reinforced thermoplastic resin composite base materials are required in a subsequent step, and the operation becomes complicated. On the other hand, if the number exceeds 2,000, the glass fiber strand becomes thicker, so that it is not easy to impregnate the thermoplastic resin between the monofilaments, and the resulting long-fiber glass reinforced thermoplastic resin composite base material becomes thicker and flexible. Inferior.

The thermoplastic resin used in the present invention includes:
There is no particular limitation, and various commercially available resins can be used. In particular, polyolefin resins and polyamide resins are suitable from the viewpoints of impregnation into glass fibers, cost, and physical properties. 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.

As a method of impregnating the glass fiber strand with a thermoplastic resin, the glass fiber strand is fed into a resin impregnation tank, and is impregnated with the resin by a melt impregnation method. A method of pulling out from the nozzle and cutting to a length of 3 to 100 mm can be adopted. By pulling out one glass fiber strand from one nozzle in this way,
As described above, the glass can be easily pulled out from the nozzle, the glass content can be increased, and the generation of fluff can be reduced.

The average diameter of the long fiber glass reinforced thermoplastic resin composite substrate thus obtained is 1.0 mm or less.
If the average diameter exceeds 1.0 mm, the flexibility becomes poor,
Since it takes time for heat to be transmitted to the center during injection molding, the fibers are strongly subjected to mechanical shear, and the fibers break, and the remaining fiber length is undesirably shortened.

The length of the long fiber glass reinforced thermoplastic resin composite substrate is 3 to 100 mm as described above.
If the length is shorter than 3 mm, the residual fiber length of the molded product becomes short, so that it is not preferable. If the length exceeds 100 mm, it becomes difficult to supply the composite base material from the hopper with a normal injection molding machine, which is not preferable.

The glass content is 60 to 80 vol.
%, Preferably 65 to 80 vol%. 60vo
If the amount is less than 1%, the cost advantage when diluted and molded in combination with a thermoplastic resin is small, and if it exceeds 80% by volume, the amount of the matrix surrounding the fibers is too small, which may cause poor dispersion of the glass fibers at the time of molding or the residual. It is difficult to increase the fiber length.

Further, the resin impregnation rate of the composite base material must be 95% or more. Below this, the mechanical properties of the obtained molded article become non-uniform, and voids not impregnated with the resin tend to become defects, which is not preferable.

Here, the impregnation ratio means that the cross section of the composite
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.

[0027]

[Equation 1] {(total sectional area-void area) / total sectional area} × 1
00 (%)

Further, the composite substrate of the present invention has a curvature R ≦ 30D × V (D = average diameter, V = Glass content: vol% / 100, and the unit of R and D needs to be mm). The smaller the curvature R is, the more excellent the flexibility is, and it is difficult to break at the time of injection molding, so that the remaining fiber length can be lengthened. When the curvature R exceeds 30D × V, the rigidity is high and the flexibility is inferior, so that the remaining fiber length is short, and a sufficient reinforcing effect cannot be obtained.

The curvature R is a value measured by the method shown in FIG. That is, first, a test piece (composite base material before cutting) 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 both ends 50mm are fixed to the chucks 12 and 13 of the tensile tester. Then, the chucks 12, 1
3 was moved and pulled at a speed of 10 mm / min, and the length L of the chuck interval when buckling was measured.
, The length of the loop 10a was calculated, and the length of the loop 10a was divided by 2π to obtain R.

[0030]

Example 1 An unsplit glass fiber strand having an average diameter of 13 μm and a convergence number of 600 was introduced into an acid-modified molten polypropylene (260 ° C.) having an MI of 40 and subjected to melt impregnation. 50 from a nozzle with an inner diameter of 0.42 mm
Pull out at a speed of m / min, length 6m with a pelletizer
m.

The long fiber glass reinforced thermoplastic resin composite base material thus obtained has an average diameter of 0.42 mm, a glass content of 67 vol%, an impregnation rate of no void, and n = 5.
Was 100% on average.

The glass content was measured by heating the obtained long fiber glass reinforced thermoplastic resin composite substrate in an electric furnace at 600 ° C. to burn off the resin, and then measuring the weight of the remaining glass. The measurement gave a glass content of 85 wt%. From this value, the specific gravity of the resin was 0.91, and the specific gravity of the glass fiber was 2.54, which was converted to vol%.

When the curvature R of the composite base material before cutting was measured by the method shown in FIG. 1, the curvature R at the time of buckling was n
= 5 was 6.0 mm on average and excellent in flexibility.

The long fiber glass reinforced thermoplastic resin composite base material thus obtained was diluted with non-reinforced polypropylene having MI = 40 so that the glass content was 30 wt%, and ASTM was performed using an injection molding machine having a mold clamping pressure of 80 t. D638, D79
A test piece for measuring physical properties according to D.256 was molded.

Example 2 Acid-modified fused polypropylene with MI = 40 (260
° C) and melted nylon 6.6 with MI = 40
Except that (320 ° C.) was used, a long fiber glass reinforced thermoplastic resin composite substrate was obtained in the same manner as in Example 1.

The long fiber glass reinforced thermoplastic resin composite substrate thus obtained has an average diameter of 0.42 mm and a glass content of 67 vol% (Example 1 was repeated except that the specific gravity of the resin was 1.14). And the impregnation rate was 100% with no voids found. The curvature R of the composite base material before cutting was buckled at 6.5 mm.

The long fiber glass reinforced thermoplastic resin composite base material thus obtained was treated with non-reinforced nylon 6.6 having MI = 40.
, So that the glass content becomes 30 wt%, and ASTM D638, D79 are used with an injection molding machine having a mold clamping pressure of 80 t.
A test piece for measuring physical properties according to D.256 was molded.

COMPARATIVE EXAMPLE 1 Three unsplit glass fiber strands having an average diameter of 13 μm and a convergence number of 600 were aligned to form M.
I = 40 acid-modified molten polypropylene (260 ° C)
After being melted and impregnated, it was pulled out from a nozzle having an inner diameter of 0.73 mm at a speed of 30 m / min, and cut into a length of 6 mm with a pelletizer.

The long fiber glass reinforced thermoplastic resin composite substrate thus obtained had some fluffs on the surface. The average diameter of the obtained long fiber glass reinforced thermoplastic resin composite base material was 0.73 mm, and the glass content was 67 vol%.
(The measurement method was the same as in Example 1), and the impregnation rate was 94%. Further, the curvature R of the composite base material before severing at the time of buckling is 16.
0 mm, which was inferior in flexibility.

Using the long fiber glass reinforced thermoplastic resin composite substrate, injection molding was performed in the same procedure as in Example 1 to obtain a test piece for measuring physical properties.

COMPARATIVE EXAMPLE 2 Twenty-five unsplit glass fiber strands having an average diameter of 13 μm and a convergence number of 600 were aligned, and an MI = 40 acid-modified molten polypropylene (26)
0 ° C.) and after melt impregnation, the inner diameter is 2.2 m
The nozzle was withdrawn at a speed of 3 m / min from a nozzle of m and cut into a length of 6 mm with a pelletizer. If the drawing speed was further increased, the fibers were broken and could not be led to the pelletizer, resulting in low productivity.

The long fiber glass reinforced thermoplastic resin composite substrate thus obtained had an average diameter of 2.2 mm, a glass content of 60.7 vol% (the measurement method was the same as in Example 1), and an impregnation rate of 93%. there were. Moreover, the curvature R of the composite base material before cutting when buckling was 51.0 mm, which was inferior in flexibility.

Using the long fiber glass reinforced thermoplastic resin composite substrate, injection molding was performed in the same procedure as in Example 1 to obtain a test piece for measuring physical properties.

COMPARATIVE EXAMPLE 3 Acid-modified fused polypropylene with MI = 40 (260
° C) and melted nylon 6.6 with MI = 40
Except for using (320 ° C.), a long fiber glass reinforced thermoplastic resin composite substrate was obtained in the same manner as in Comparative Example 2. The drawing speed was limited to 3 m / min.

The long fiber glass reinforced thermoplastic resin composite substrate thus obtained had an average diameter of 2.2 mm, a glass content of 60.7 vol% (the measurement method was the same as in Example 2), and an impregnation rate of 93%. there were. Moreover, the curvature R of the composite base material before severing at the time of buckling was 63.0 mm, which was inferior in flexibility.

Using the long fiber glass reinforced thermoplastic resin composite substrate, injection molding was performed in the same procedure as in Example 2 to obtain a test piece for measuring physical properties.

Using the test pieces for measuring physical properties obtained in Examples 1 and 2 and Comparative Examples 1 to 3, the results of measuring various physical properties are shown in Table 1.
Shown in Table 1 shows the productivity, impregnation rate,
The curvature at the time of buckling, the dispersibility of the glass fiber in the test piece, and the remaining fiber length are described together. The productivity was evaluated on the basis of ◎: good,…: normal, ×: poor, and the glass fiber dispersibility was 、.
… Not visually confirmed,…: 1-2, △: 3-5, ×
... Evaluated on the basis of 6 or more. As the remaining fiber length, the molded test piece was heated in an electric furnace at 600 ° C.
After burning off the resin, the fiber length was measured using a projector at n = 200, and the average value was determined.

[0048]

[Table 1]

From the results shown in Table 1, the resin impregnation rate is high,
It can be seen that the molded articles of Examples 1 and 2 having a small curvature R at the time of buckling have long residual fiber lengths, good fiber dispersibility, and excellent tensile strength, bending strength and the like.

On the other hand, the molded articles of Comparative Examples 1 to 3 using the composite base material manufactured by pulling out a plurality of glass fiber strands and pulling them out from one nozzle are the molded articles of the corresponding examples. It can be seen that the productivity and the dispersibility of the glass fibers are poor, the remaining fiber length is short, and the tensile strength and the bending strength are inferior to those of the above.

[0051]

As described above, the long fiber glass reinforced thermoplastic resin composite base material of the present invention has an extremely high glass content and resin impregnation rate, and is excellent in flexibility. The dispersibility of the glass fiber when formed into a molded product by the method is good, and the length of the remaining fiber is long. For this reason,
Even if the glass content is the same, a molded article having more excellent physical properties can be obtained, and the cost advantage at the time of dilution molding is great.

[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 long fiber glass reinforced thermoplastic resin composite base material.

FIG. 3 is a schematic view showing a state where a glass fiber strand enters a nozzle in a conventional method for producing a long fiber glass reinforced thermoplastic resin composite substrate.

[Description of Signs] 10 Test piece of glass fiber base material containing thermoplastic resin 10a Loop 11 Collar 12, 13 Chuck S, S1, S2, S3 Glass fiber strand N Nozzle

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B29B 11/16 B29B 15/08-15/14 C08J 5/04-5/10 C08J 5/24

Claims (4)

(57) [Claims] 1. A long fiber glass reinforced thermoplastic made by impregnating a single glass fiber strand obtained by bundling a plurality of glass monofilaments without applying a split with a thermoplastic resin and cutting the glass fiber into a predetermined length. A) a resin composite base material, A) an average diameter of 1.0 mm or less, B) a length of 3 to 100 mm, C) a glass content of 60 to 80 vol%, and D) the thermoplastic resin. E) When the buckling limit when bent before bending is expressed by curvature, curvature R ≦ 30D × V (D = average diameter, V = glass content) Rate: vol% / 100, and the unit of R and D is mm). 2. The method according to claim 1, wherein the number of bundles of the glass fiber strand is two.
2. The long fiber glass reinforced thermoplastic resin composite substrate according to claim 1, wherein the number of the glass monofilaments is from 00 to 2000 and the average diameter of the glass monofilament is from 6 to 17 [mu] m. 3. The long fiber glass reinforced thermoplastic resin composite substrate according to claim 1, wherein the thermoplastic resin is a polyolefin resin or a polyamide resin. 4. A glass fiber strand obtained by bundling a plurality of glass monofilaments without applying splitting is impregnated with a thermoplastic resin by a melt impregnation method. A) having an average diameter of 1.0 mm or less, B) having a length of 3 to 100 mm, C) having a glass content of 60 to 80 vol%, and D). E) impregnation rate of the thermoplastic resin is 95% or more; E) when a buckling limit when bent before being cut is represented by curvature, curvature R ≦ 30D × V (D = average diameter, A method for producing a long-fiber glass-reinforced thermoplastic resin composite substrate, wherein a composite substrate having V = glass content: vol% / 100, and the units of R and D is mm) is obtained.