JP3273968B2 - Manufacturing method of reinforced stampable sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a reinforced stampable sheet containing glass fibers in a thermoplastic resin.

[0002]

2. Description of the Related Art A stampable sheet is made of a thermoplastic resin in which continuous glass fibers are laminated, and has excellent strength, particularly excellent impact strength. FIG. 5 shows a cross section of a conventional reinforced stampable sheet, in which thermoplastic resin layers 1a and 1a are provided.
Since the continuous fiber glass layers 2a and 2b are laminated and integrated between b and 1c, and the molded article using this sheet is excellent in impact resistance, it is widely used for automobile parts such as bumpers. I have.

[0003]

However, since the continuous fibers are entangled with each other, the flowability is lower than that of the resin, and the distribution of the continuous fibers becomes coarse and dense when the continuous fibers are stretched into a sheet. There was a problem that high strength could not be obtained. Therefore, for example, by using the reinforced stampable sheet and pressing as shown in FIG.
In the case where the molded article 4 as shown in FIG. 1 is molded, the fluidity of the continuous fiber is lower than that of the resin, so that the fiber does not reach the narrow gap between the molding dies 5 and 6, that is, the thin peripheral edge of the molded article 4 The continuous fiber does not spread to the portion 4a and becomes a resin-rich portion, and the strength of the peripheral portion 4a is weaker than other portions.
There is a problem that a part with low strength is generated.

[0004] The present invention has been made in view of the problems of the prior art, and its object is to provide a method of manufacturing a reinforced stampable sheet having a uniform intensity throughout.

[0005]

[MEANS FOR SOLVING THE PROBLEMS] To achieve the above object
And a method for manufacturing a reinforced stampable sheet according to claim 1.
In the case of thermoplastic resin sheets and continuous glass fiber sheets,
And passed through the heating furnace by the conveyor.
Melts the thermoplastic resin in the continuous glass fiber layer.
For manufacturing method of reinforced stampable sheet to be integrated by fusion impregnation
In this case, short glass fibers are mixed in advance in the thermoplastic resin.
It is intended to enter.

[0006]

[Function] Since continuous glass fibers are entangled with each other, it is difficult to distribute them uniformly in the thermoplastic resin. However, since the short glass fibers are independent single bodies, they are not restricted to each other, so that they are uniformly distributed in the resin. Compared to a reinforced stampable sheet that is distributed and contains only continuous glass fibers, the unevenness in strength due to the variation in the distribution of continuous glass fibers is smoothed to the extent that the short glass fibers are widely and uniformly distributed.

In a press-formed product using the reinforced stampable sheet, the short glass fibers flow integrally with the thermoplastic resin and spread to narrow gaps between the molds. That is, short glass fibers are uniformly distributed to the end portion of the molded article.

[0008]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a reinforced stampable sheet according to the present invention, and FIG. 2 is a sectional view of a press-formed product using the sheet. In these figures, the reinforced stampable sheet is a polypropylene layer 1 in which short glass fibers 11 are dispersed.
A continuous glass fiber layer 12 (12a, 12b) melt-impregnated with polypropylene is laminated and integrated between 0 (10a, 10b, 10c).

In the polypropylene layer 10, short glass fibers 11 are uniformly dispersed in polypropylene, but the length of short glass fibers 11 dispersed in polypropylene is 3 mm.
A length of about 13 mm is desirable. That is, when the thickness is 3 mm or less, an increase in impact resistance cannot be so much expected, and 3 mm or more is required to increase the impact resistance. On the other hand, if it is 13 mm or more, there is a high risk of breaking when kneading with polypropylene. Further, if the fiber is longer than this, the fluidity is poor and the dispersion rate is reduced.
mm or less is desirable.

The continuous glass fiber layer 12 has a form in which endless continuous glass fibers 13 are entangled, and has a structure in which polypropylene is melt-impregnated between the continuous glass fibers. And the continuous glass fiber 13 and the short glass fiber 11 for polypropylene in the stampable sheet.
The range of the total weight of the glass fiber combined with is naturally determined in the reinforced stampable sheet, and the ratio of the short glass fiber 11 to the total weight of the glass fiber is 5 to 5.
20% is desirable. The smaller the proportion of the short glass fibers 11, the greater the proportion of the continuous glass fibers 13, so that the impact resistance is excellent, but the formability is poor. At 5% or less, when forming a press-formed product as shown in FIG. 2, the glass fibers are not uniformly distributed, for example, the glass fibers are not sufficiently dispersed in the peripheral portion or a resin-rich portion is formed. The strength is not constant. On the other hand, the greater the proportion of the short glass fibers 11, the more uniform the distribution of the glass fibers can be achieved, but the smaller the number of the continuous glass fibers 13, the lower the impact resistance. That is, when the molded article shown in FIG. 2 was molded, when the glass short fiber was 20% or more, there was no stickiness and the impact strength was poor.

In the above embodiment, the polypropylene layer 10
In this structure, the short glass fibers 11 are dispersed in advance, but as shown in FIG. 3, the short glass fibers 11 are not dispersed in the polypropylene layer 10, but the continuous glass fiber layers 12 (12a , 12b) have a structure in which short glass fibers 11 are dispersed. FIG. 4 is an overall configuration diagram of an apparatus for manufacturing the reinforced stampable sheet shown in FIG. Reference numeral 20 denotes a coil body in which a polypropylene sheet S1 in which short glass fibers 11 are dispersed is wound into a coil shape, and the polypropylene sheet S1 is unwound at a predetermined speed synchronized with a transport speed of a transport belt conveyor 40 described later. It is sent forward. Reference numeral S2 denotes a continuous glass fiber sheet (mat), which is formed into a sheet shape in which continuous glass fibers 13 are entangled with each other.
Is sent out along. Reference numeral 30 denotes a resin extruder that extrudes molten polypropylene and supplies it between the upper and lower continuous glass fiber sheets S2, S2. Reference numeral 40 denotes a conveyor belt conveyor, which cooperates with a conveyor pressure belt conveyor 50 disposed to face upward and the polypropylene sheet S1,
The molten polypropylene and the continuous glass fiber sheet S2 are transported in a laminated state. A heating furnace 60 is provided in the sheet conveying path formed by the belt conveyors 40 and 50, and the continuous fiber sheet S2 is impregnated with the polypropylene melted by passing the laminated sheets through the heating furnace 60. And integrated. A cooling furnace 70 is provided in front of the heating furnace 60, and the stacked sheets are cooled and condensed in the heating furnace 60 to produce a reinforced stampable sheet having a sectional structure shown in FIG.

[0012]

As is apparent from the above description, according to the method for manufacturing a reinforced stampable sheet according to the present invention, continuous glass fibers are entangled with each other, so that it is difficult to distribute them uniformly in a thermoplastic resin. Since the short glass fibers are independent and independent of each other, they are not bound to each other, so they are evenly distributed in the resin, and the short glass fibers have a wider area compared to a reinforced stampable sheet containing only continuous glass fibers. Because of the uniform distribution, the unevenness in strength due to the variation in the distribution of continuous glass fibers is smoothed, and the strength of the entire reinforced stampable sheet is made uniform. Further, as the strength of the entire reinforced stampable sheet is made uniform, the strength between mass-produced reinforced stampable sheets is also made uniform.

In the press-formed product using the reinforced stampable sheet, the short glass fiber flows integrally with the thermoplastic resin and spreads to the narrow gap between the molds, that is, the short glass fiber reaches the end portion of the molded product. Are uniformly distributed, so that a certain degree of strength is ensured even at a thin portion or an end portion.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a first embodiment of a reinforced stampable sheet according to the present invention.

FIG. 2 is a cross-sectional view of a molded product press-formed using the reinforced stampable sheet shown in FIG.

FIG. 3 is a cross-sectional view of another embodiment of the reinforced stampable sheet of the present invention.

FIG. 4 is an overall configuration diagram of an apparatus for manufacturing the reinforced stampable sheet shown in FIG.

FIG. 5 is a cross-sectional view of a conventional reinforced stampable sheet.

FIG. 6 is an explanatory diagram illustrating a state of press-molding using the reinforced stampable sheet shown in FIG. 5;

FIG. 7 is a perspective view of a molded product formed by using the press shown in FIG. 6;

[Explanation of symbols]

10 (10a, 10b, 10c) Polypropylene layer which is a thermoplastic resin in which short glass fibers are dispersed 11 Short glass fibers 12 (12a, 12b) Continuous glass fiber layer 13 Continuous glass fiber S1 Polypropylene sheet S2 Continuous fiber sheet

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-55-152058 (JP, A) JP-A 64-81826 (JP, A) JP-A-4-201420 (JP, A) JP-A-2- 92756 (JP, A) JP-A-4-135714 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29B 11/16 B29B 15/08-15/14

Claims (1)

(57) [Claims] 1. A thermoplastic glass sheet and a continuous glass fiber sheet.
And passed through the heating furnace by the conveyor.
The thermoplastic resin in the continuous glass fiber layer.
Method for producing reinforced stampable sheet to be melt-impregnated and integrated
In the above, short glass fibers are previously contained in the thermoplastic resin.
Enhanced stampable sea characterized by being mixed
Manufacturing method.