JPS62208932A - Plastic sheet dispersed by fibrous filler - Google Patents

Abstract

PURPOSE:To enable prevention of cutting off and uniformity of the thickness direction, by a method wherein the titled filler of more than a specific ratio is split down to single fibers having a specific length is dispersed within plastics. CONSTITUTION:3-100mm fibers more than 10wt% of which has been split down to single fibers are dispersed within plastics. The plastics thermoplastic and the material of a fibrous filler to be used, may be formed of glass or a metal or organic substance. It is possible to obtain a sheet which hardly possesses an injury on the fiber the whole or a part of which is dispersed uniformly by splitting down to single fibers, possesses neither a mating surface nor distribution irregularity of the fiber in the direction of a thickness of the sheet and having a weight of more than 900g/m<2>.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention is a method of producing a plastic material by uniformly dispersing fibers having a length of 3 to 100 mm in a state in which 20% by weight or more of the fibers are defibrated into single fibers. It relates to thermoplastic sheets.

[Conventional technology]

At present, plastics mixed with various fibrous substances are used in various situations.

When obtaining such fiber-filled plastic materials,
First, fibers are usually kneaded with plastic using a kneader or an extruder to form a molding material.

By the way, since the substances added to plastics essentially form a heterogeneous system, various studies have been made regarding their uniform mixing as this technology progresses.

Specifically, an impregnation type sheet is obtained by impregnating a continuous mat of fibers with a resin solution (U.S. Patent No. 4).
098943), a mixed type in which short fibers are mixed with a continuous fiber mat (Japanese Patent Publication No. 54-36193), or a type in which short fibers are dispersed and mixed in water using a paper manufacturing method (Japanese Patent Publication No. 60-1999). -158228 Publication)
and so on.

[Problem that the invention seeks to solve]

When attempting to uniformly mix fibrous fillers by, for example, the melt AM method, a relatively large shear stress is generated due to the kneading operation in the synthetic resin forming a molten high-viscosity fluid. 1a fiber, for example, about 6
Plastic Age September 1985 issue 129 often causes cutting from lengths of about m to about 0°5w.
It is described on pages 134 to 134.

Therefore, it is short like this! ! The plastic sheet, which contains a lot of fiber, is the i! ! It has the disadvantage that physical properties such as impact strength and creep properties are significantly reduced.

On the other hand, the method of impregnating a continuous fiber mat with a resin solution is
Although the mechanical strength is further improved, it has the disadvantage that it is difficult to flow during stamping because the m-fibers are not only converged but also intertwined with each other. For example, if it is attempted to form a rib-like portion 2) for the molded body portion 1 as shown in the drawings, the fibers will not be filled up to the tip and no reinforcing effect will be produced.

In addition, for types that mix short fibers with continuous fiber mats,
If the short wA fibers are not loosened, the same result as in the previous case will occur.

The last case using the paper manufacturing method is excellent because it has good dispersibility and no damage to the fibers, but the sheets that can be produced in one process are thin (at most 900 g/m' or less). do not have.

Therefore, if you want to obtain a thick sheet I, you have no choice but to stack it or form a special production line and manufacture it in a batch process, but in such cases, the final sheet I The dispersion state of fibers differs in the thickness direction, and in the case of a lamination method, the concentration may be periodic, and in the case of a batch method, the concentration may be high in the lower part, resulting in non-uniform performance in the thickness direction.

[Means for solving problems]

In light of these circumstances, as a result of extensive research, we have found that m-fibers with a length of 3 to 100 centimeters, in which more than 10% by weight of the fibers have been defibrated to single fibers, are placed in plastic. The result was a thermoplastic sheet made of dispersed particles.

[For production]

The plastic referred to in the present invention is thermoplastic, and the fibrous filler used here may be made of glass, carbon, metal, or organic material, and its m-line length is: Preferably, the number is 1001 or less.

More details: Length! It is preferable to use one in which the relationship between the diameter and the diameter d (aspect ratio = l/d) is between approximately 100 and 20,000.

Generally, such W4 fibers are bundles of a suitable number of fibers, but in the case of the present invention, at least 10% by weight of the fibers in the plastic are defibrated into single fibers. It targets things.

〔Example〕

Hereinafter, the structure and effects of the present invention will be explained by specifically showing examples.

Example 1 - ■ ■ Synthetic resin: Commercially available polypropylene powder average particle size 20
0 μmφ ■ m, i: Commercially available E glass fiber, 13-kaku chop, Mixer, Retzel mixer (manufactured by Mitsui Miike Kako 8!, Retzel mixer FMIOB type, capacity 9J) Mixing and forming strip ■ Polypropylene powder 30 parts by weight , 70 parts by weight of the fibers were placed in a mixer, and the blades were rotated at 3900 rpm for mixing.

(2) The mixtures obtained by varying the mixing time were observed under an optical microscope, and the loosened state of the IA fibers and the m-pole length were measured.

■ Heat the mixture at 200℃ and 40k using a hot press machine.
Heat and pressurize to g/clI and make a sheet of 3 x 160 x 160 cm.

The weight of this sheet was 3300 g/rn' (specific gravity 1.1).

The tensile strength of each of the sheets obtained as described above was measured, and the results are shown in the table below.

10 5 13
3.520 10
13 3.830 2
0 13 5.58
0 40 12.5
6.0120 60
12.5 7.5300
75 12.0 7.8
600 85 11.0
g, 0900 90
10.5 8.5) - Omi ■ When carried out according to the present invention, almost no damage to the fibers was observed and the appearance of the sheet surface was good.

■ It was observed that the reinforcing effect was small when the proportion of single m fibers among the fibers was 10% or less.

■ Even with this method, care must be taken because prolonged mixing will cause damage to the 1a fibers.

Comparative Example 1 Example 1 was repeated using a glass m-fiber having a fiber length of less than 3 strands, but in this case no reinforcing effect was observed.

Comparative Example 2 Contrary to the previous case, when m-fibers with a wA fiber length of 100 m or more were not used, uniform dispersion could not be achieved by normal mixing operations.

[Effects of the Invention] By implementing the present invention, the following effects can be enjoyed.

(1) There is almost no fiber loss (cutting), all or part of the fibers can be unraveled into single meter fibers, and the fibers can be uniformly dispersed in the plastic.

(2) It is possible to obtain a sheet that has no joints or uneven distribution of fibers in the thickness direction of the sheet, and that can pass a weight of 900 g/m or more.

(3) The appearance is good, the m-fibers are uniformly distributed even in the fine rib-like portions, and the quality of the molded product is constant.

[Brief explanation of drawings]

The drawing is a cross-sectional view of a rib-like portion, which is shown as an example for explaining a complicated portion of a molded body. 1... Molded body main part, 2... Rib part.

Claims (6)

[Claims] (1) A thermoplastic plastic sheet comprising fibers having a length of 3 to 100 mm, in which 10% by weight or more of the fibers have been defibrated into single fibers, and are dispersed in plastic. (2) The thermoplastic plastic sheet according to claim 1, which does not have a laminated resin layer in the thickness direction of the sheet. (3) The thermoplastic plastic sheet according to claim 1, which does not have a fiber concentration distribution in the thickness direction of the sheet. (4) The thermoplastic plastic sheet according to claim 1, which uses at least one of glass fiber, carbon fiber, metal fiber, or organic fiber. (5) The thermoplastic plastic sheet according to claim 1, having a weight of 900 g/m^2 or more. (6) The thermoplastic plastic sheet according to claim 1, which uses fibers having an aspect ratio of 100 to 20,000.