JPH05116228A - Manufacture of glass fiber reinforced plastic regenerated sheet and glass fiber reinforced plastic regeneration molded product - Google Patents

Abstract

PURPOSE:To provide the manufacturing method of a regeneration molded product of mechanical properties equivalent to that of an original molded product by using a product to be recycled and manufacture a regenerated sheet. CONSTITUTION:A plurality of cut pieces of a glass fiber reinforced plastic molded product including resin of 30-90wt.% and fiber of 10-70wt.% having the fiber diameter of 5-30mum and fiber length of 5-45mm and/or cut pieces formed at the time of forming the stamping forming of glass fiber reinforced plastic having the cut length of 2 times or more of the glass fiber are used, heated and formed to manufacture a glass fiber reinforced plastic regenerated sheet. A glass fiber reinforced plastic regeneration molded product is also manufactured by using a plurality of said regenerated sheets or using an original sheet and a plurality of regenerated sheets and heating at least one time and forming.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass fiber reinforced plastic recycled sheet capable of stamping molding and a method for producing a glass fiber reinforced plastic recycled molded product using the same, and particularly to maintaining the fiber length of the contained glass fiber. The present invention relates to a method for producing a regenerated sheet, which is used to obtain a regenerated sheet having the same mechanical properties as the original sheet.

[0002]

2. Description of the Related Art Plastics reinforced with glass fibers are
As a material that is lighter in weight and has higher mechanical properties than other materials, demand for automobiles and building materials is growing significantly. On the other hand, the recycling of plastics has become a problem due to environmental issues. However, in any form of glass fiber reinforced plastic, it is difficult to separate and recycle the glass fiber and the matrix resin. When considering recycling of the products to be recycled, it was necessary to consider a recycling method as a composite body in which glass fiber and matrix resin were integrated. For fiber reinforced plastics containing very short fibers (1 mm or less) such as those used in injection molding, the product to be recycled can be crushed and re-pelletized to give the original product. .. However, those containing long glass fibers such as 5 mm or more used in stamping molding are
In the prior art, there is no choice but to crush it into pellets for injection molding. In this method, the fiber is shortened during crushing, and a remolded product that maintains a certain fiber length that can be stamped and molded is obtained. I couldn't.

[0003]

According to the prior art, when a molded product made of glass fiber reinforced plastic containing relatively long fibers having a fiber length of 5 to 45 mm is reused, the fiber length is maintained while maintaining the fiber length. Can not be a molded product of
There was no choice but to pulverize it into pellets for injection molding.
With this, it is not possible to take advantage of the fact that the inclusion of long fibers has high mechanical properties such as impact properties and bending properties. Further, the superiority of stamping molding over injection molding, that is, high productivity cannot be utilized. That is, in the prior art, when trying to recycle, the stamping molded product is finely pulverized, resulting in shortening of the fiber, so that it stops to the extent of being diverted to pellets for injection molding, while maintaining the fiber length, It was not possible to manufacture a recycled molded product equivalent to the original molded product. Therefore, an object of the present invention is to use a cut piece obtained by cutting a stamping molded product at the time of recycling, and / or a recycling object such as a cut piece produced when cutting a stamping molding sheet at the time of manufacturing the stamping molded product. Alternatively, the cut piece and the original plate before cutting the stamping molding sheet are used to obtain a regenerated sheet in which the fiber length is maintained, and using this, it has the same mechanical properties as the original molded article. It is to provide a manufacturing method for obtaining a remolded product.

[0004]

In order to solve the above problems, the present inventors have studied various cutting conditions, heating and molding conditions, and as a result, have a glass having mechanical properties equivalent to those of the original molded product. The present invention has been achieved by establishing a manufacturing method capable of obtaining a fiber-reinforced plastic recycled molded product. That is, the first aspect of the present invention is a glass fiber reinforced plastic containing 30 to 90 wt% of a thermoplastic resin and 10 to 70 wt% of a glass fiber having a fiber diameter of 5 to 30 μm and a fiber length of 5 to 45 mm. The cut length produced by cutting the reinforced plastic molded product and / or the glass fiber reinforced plastic stamping molding sheet at the time of molding is 2 times the fiber length of the glass fiber.
The step obtained by the step of (2) the step of (1), wherein the cutting step is performed as a double or more, and / or the step of selecting the cut pieces whose cutting length is at least twice the fiber length of the glass fiber among the cut pieces. Heating a plurality of the cut pieces at a temperature not lower than the melting point or softening point of the thermoplastic resin and not higher than the decomposition temperature,
(3) A method for producing a recycled glass fiber reinforced plastic sheet, which comprises a step of forming the sheet obtained by the step (2) by pressing to form a sheet. Furthermore, in the step (2), it is suitable when the cut pieces 30 to 100 wt% and the original plate 0 to 70 wt% are both heated. Further, according to the second aspect of the present invention, heating and molding are performed at least once by using a plurality of recycled sheets of the first aspect or by using a plurality of original sheets and recycled sheets of the first aspect. A glass fiber reinforced plastic remolded product thus obtained is provided. The glass fiber reinforced plastic recycled sheet of the first aspect of the present invention is preferably obtained by heating and molding together with the original plate, and further, 30 to 100 wt% of the cut pieces and 0 to 70 wt% of the original plate are heated and molded. It is particularly preferable when it is obtained by Furthermore, according to a second aspect of the present invention, using a plurality of recycled sheets of the first aspect or using a plurality of original sheets and recycled sheets of the first aspect, heating at least once,
There is provided a method for producing a glass fiber reinforced plastic recycled molded product, which is characterized by molding.

The method for producing the recycled glass fiber reinforced plastic sheet and the recycled molded article of the present invention will be described in detail below. In the present invention, the glass fiber reinforced plastic as a raw material is a product to be recycled and / or an original plate described below, and the thermoplastic resin is 30 to 90 wt%.
%, And 10 to 70 wt% of glass fiber. The thermoplastic resin that is the matrix resin may be any thermoplastic resin, for example, polypropylene, polyolefin resin such as polyethylene, saturated polyester resin,
Examples thereof include polycarbonate resin, thermoplastic polyurethane resin, polyamide resin and the like. Further, the glass fiber contained has a fiber diameter of 5 to 30 μm and a fiber length of 5 to 45 μm.
mm is desirable. If the fiber diameter is less than 5 μm, the adhesion between the resin and the fiber interface becomes difficult during production. Further, if the fiber diameter is more than 30 μm, it is difficult to maintain sufficient mechanical properties. When the fiber length is less than 5 mm, it is not possible to obtain a sufficient reinforcing effect by the fibers as the composite material, and when it is more than 45 mm, the fluidity at the time of molding is lowered and it becomes difficult to mold the details. .. Further, the composition of the glass fiber may be one that is usually used as a reinforcing material. This glass fiber is usually in the matrix resin,
It is arranged non-directionally, but is not limited to this.

If the thermoplastic resin is more than 90 wt% or the glass fiber content is less than 10 wt%, it is not possible to obtain a sufficient reinforcing effect by the fiber as the composite material, and the thermoplastic resin is less than 30 wt% or the glass. If the fiber content exceeds 70 wt%, the fibers and the resin cannot be sufficiently adhered during molding, and the properties as the composite material cannot be obtained.

The original plate in the present invention is the glass fiber reinforced plastic sheet just before the stamping molding sheet is cut during stamping molding. Further, the cut pieces in the present invention are products to be recycled, and include cut pieces obtained by cutting a glass fiber reinforced plastic molded product, and / or cut pieces generated at the time of cutting a stamping molding sheet. The cut length of the cut pieces is preferably twice or more the fiber length of the contained glass fibers.

The cutting length refers to the average length of each side when the cut piece is a triangle or a quadrangle, and the maximum outer shape when the cut piece has a polygonal shape other than a triangle or a quadrangle or an irregular shape. Refers to dimensions. The fiber length refers to the average length of the glass fibers contained in the glass fiber reinforced plastic.

In order to obtain cut pieces, it is only necessary to cut recycle stamping molded articles, cut pieces of stamping molded article sheets (stamping molding sheets), and the like, and if necessary, Cut pieces having a suitable cutting length may be selected.

The cutting method may be an ordinary method. It is preferable that the cut pieces have a regular shape as much as possible, but an irregular shape may be used. It is more preferably a quadrangle, particularly preferably a square.

The reason why the cutting length is determined is that the cutting causes shortening of fibers, and if this degree is large, the mechanical properties are deteriorated as compared with the original sheet or molded product. If the molded product is reused, it must be cut. Also,
The sheet fragment used when cutting the stamping molding sheet has already been cut at the time of stamping molding or the like. That is, when reusing a product to be recycled, short fibers are produced in any case. Therefore, the cutting size should be as large as possible. In addition, when a material having an extremely short cutting length is used, a separated portion (weld) between the fiber and the resin is generated during molding, which also leads to deterioration in characteristics. However, there is a certain relationship between the fiber length of the glass fiber contained in the product to be recycled and the fiber length after cutting, and it is possible to keep the fiber length after cutting above a certain level by selecting the cutting length appropriately. Is. Now, assuming that the fiber length of the fiber contained in the original product to be recycled is a and the length of one side is cut to be cut into a square, and A / a is 2 or more,
The fiber length after cutting can maintain about 90% of the original fiber length. When a recycled sheet is produced using a cut piece having such a fiber length, a sheet having the same characteristics as the original sheet can be obtained. Therefore, the cut length is preferably twice or more the glass fiber length. Further, it is desirable that the cutting length is as constant as possible so that a temperature difference does not occur between the cut pieces during heating.

When the cut piece having the above-mentioned cut length is exposed to a temperature equal to or higher than the softening point or melting point of the resin, the resin is melted and softened to be in a moldable state. It is possible to put them in a molding machine as they are for molding, but in this case, a part (weld) in which the matrix resin and the fiber are separated occurs, and a molded product having uniform properties cannot be obtained. In the present invention, a regenerated sheet is obtained by heating and cutting an appropriate amount of cut pieces and the like in a melted and softened state, and compressing them with a press to form them. The regenerated sheet thus obtained contains the above-mentioned weld, but it is possible to make the fiber unevenness uniform by forming several sheets at the time of reforming, and thus the regenerated sheet and further reshaped There is no significant change in the product characteristics.

When a recycled molded product is produced from the recycled sheet, if the cutting length is at least twice that of the glass fiber, a sheet having the same characteristics as the original sheet can be obtained. A plurality of such cutting pieces and original plates are used together to produce a recycled sheet, or
By molding the recycled sheet thus obtained and the original sheet together, it becomes possible to further reduce the variation in characteristics. As a method of using the original plate together, it is also possible to heat the original plate on which the cut pieces are sprinkled and then press it. Further, after heating the original plate and the cut piece individually, the cut piece is sandwiched between two original plates. You may press in shape. As a matter of course, if the combined use ratio of the original plates is increased, the property maintenance ratio and the property stability are improved. However, since the recycling rate decreases when the ratio of the original plate used is increased, the content ratio of the original plate is 0 to 70w.
t% is good. Furthermore, 0 to 50 wt% is preferable. A first aspect of the present invention is a plurality of cut pieces, or
It is a method for producing a recycled sheet by heating and molding using a plurality of cut pieces and an original plate. And the second aspect uses a plurality of recycled sheets of the first aspect, or a plurality of original sheets and recycled sheets of the first aspect,
Further, it is a method for producing this recycled molded product by heating and molding at least once. As described above, according to the method of the present invention, a regenerated sheet and regenerated molded glass fiber reinforced plastic that maintains a constant fiber length and has the same mechanical properties as the original molded product or does not show a large decrease in mechanical properties. You can get the goods.

[0014]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples of the present invention. (Example 1) Polypropylene as the matrix resin (melting point 165 ° C, decomposition temperature 230 ° C), fiber length 13 m
m, a sheet for stamping molding containing 40 wt% of glass fiber having a fiber diameter of 10 μm (unit weight: 2000 g / m ² , thickness: 1.7 mm), thickness: 3.2 mm, side length: 50
A 0 mm square plate-shaped molded product was produced. This was cut into a square shape having a side length of 50 mm to obtain a cut piece. Collect a predetermined number of these cut pieces, preheat at 210 ℃ for 10 minutes,
It was compressed with a hot plate press to a thickness of 1.7 mm and a weight per unit area of 2000 g / m ² . The final pressing pressure is about 30 Kgf / cm
^{Was 2} . A plurality of reclaimed sheets obtained in this way were used, and again heated and then compression pressed to produce a square plate-shaped reclaimed article. Table 1 shows the results of measuring the bending characteristics of the molding sheet (original plate) used initially, the original molded product, the recycled sheet, and the recycled molded product. The flexural strength and flexural modulus were measured according to JIS K7055. When the recycled sheet was compared with the original plate and the recycled molded product was compared with the original molded product, the deterioration of mechanical properties was only about 10%.

[0015]

Example 2 Stamping pin used in Example 1
Forming sheet (Basis weight 2000g / m², Thickness 1.7m
m) is cut into a square shape with a side length of 50 mm and cut into pieces.
Got Collect a specified number of these cut pieces and hold at 210 ° C for 10
After preheating for a minute, a hot plate press has a thickness of 1.7 mm and a basis weight of 200
0 g / m²It was compressed so that Press pressure is the final pressure
About 30 Kgf / cm ² Met. Regeneration obtained in this way
A square plate-shaped molded product was prepared using the sheet. In Table 2
Measurement of bending properties of original plate, recycled sheet, and reformed product
The result is shown. In comparison with the molded product obtained in Example 1,
As a result, the deterioration of the properties of the recycled molded product is only about 10%.

[0017]

(Example 3) Using the original plate used in Example 1 and the cut pieces obtained by cutting the molded product, the content ratio of the original plate was changed in the range of 0 to 100 wt%. By the same method, a recycled sheet in the case of using the cut pieces and the original plate in combination was prepared, and a plurality of the obtained recycled sheets were used to obtain a molded molded article again. Figures 1 to 3 show the characteristic maintenance ratio of the mechanical properties of this recycled molded product to the mechanical properties of the original molded product.
Shown in. 1, 2, and 3, the vertical axis represents the bending strength ratio, the bending elastic modulus ratio, and the Izod impact strength ratio of the recycled molded product to the original molded product. The Izod impact test was performed according to JIS K7110. It can be seen that when the mixing ratio of the original plate is 0 to 50% by weight, the characteristics are not significantly deteriorated.

Comparative Example 1 A molded product similar to that of Example 1 was cut into a square shape having a side length of 20 mm, and a recycled sheet was obtained by the same method. Further, a molded product was prepared again using this recycled sheet. At this time, the bending strength of the recycled sheet was 57.2 MPa, and the bending elastic modulus was 2.70 GPa, which was about 50% lower than the characteristics of the original sheet. Also, the bending strength of the recycled molded product is 72.2MP.
Regarding a, the flexural modulus was 3.44 GPa, it was recognized that the characteristics were reduced by about 40% as compared with the original molded product.

Comparative Example 2 The cut piece obtained in Example 1 was preheated at 150 ° C. for 10 minutes, and then a recycled sheet and a square plate-shaped recycled molded product using the recycled sheet were prepared in the same manner as in Example 1. did. The bending strength of the recycled sheet at this time is 57.0M.
Pa and flexural modulus at 2.64 GPa showed a decrease in properties of about 50%. Further, the same cut pieces were preheated at 280 ° C. for 10 minutes, and similarly, a recycled sheet and a square plate-shaped recycled molded product using the recycled sheet were produced. At this time, the flexural strength of the recycled sheet was 68.7 MPa, and the flexural modulus was 3.19.
In GPa, the characteristic was decreased by about 40%.

Comparative Example 3 The cut pieces obtained in Example 1 were used as they were, and the same heating and compression press as in Example 1 was used.
A regenerated molded product having the same shape as the original molded product was produced in one step. The bending strength of the obtained regenerated molded product was 96.2.
The MPa and the flexural modulus are 3.78 GPa, and a characteristic deterioration of 20 to 30% is observed as compared with the characteristic of the original molded product.

[0022]

EFFECTS OF THE INVENTION According to the method of the present invention, a cut piece of fiber reinforced plastic produced when a molded product manufactured by stamping molding is reused and when a stamping molding sheet is cut is used as an object to be recycled. When a recycled sheet is created by heating and molding, and when a recycled molded product is created using this, mechanical properties such as bending properties and flexural modulus are compared to the original sheet or the original molded product. Can hold quite a bit.

[Brief description of drawings]

FIG. 1 is a graph showing a bending strength ratio (A) which is a mechanical property maintenance ratio of a molded product.

FIG. 2 is a graph showing a flexural modulus (B) which is a mechanical property maintenance ratio of a molded product.

FIG. 3 is a graph showing an Izod ratio (C) which is a mechanical property maintenance ratio of a molded product.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location // B29K 105: 08 105: 26 B29L 7:00 4F (72) Inventor Yasuji Matsumoto Chiba Prefecture Kawasaki Steel Co., Ltd., Chuo-ku, Chiba City, Kawasaki Steel Co., Ltd. Technical Research Headquarters (72) Inventor Keio Kawamura, Kawasaki-machi, Chuo-ku, Chiba City, Chiba Prefecture, Kawasaki Steel Co., Ltd. Technical Research Headquarters (72) Inventor Hidetaka Sugibe 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Prefecture Kawasaki Steel Corporation Technical Research Division

Claims (3)

[Claims] 1. A glass fiber 10 having a thermoplastic resin of 30 to 90 wt%, a fiber diameter of 5 to 30 μm, and a fiber length of 5 to 45 mm.
In a glass fiber reinforced plastic containing 70 to 70 wt%, (1) a cutting length generated when cutting a molded product of the glass fiber reinforced plastic and / or a stamping molding sheet of the glass fiber reinforced plastic during molding, (2) The step of cutting as a fiber length of the glass fiber is twice or more, and / or the cutting length of the glass fiber is two or more times the fiber length of the glass fiber. A step of heating a plurality of the cut pieces obtained in the step 1) at a temperature above the melting point or softening point of the thermoplastic resin and below the decomposition temperature, (3) obtained in the step (2) A method for producing a glass fiber reinforced plastic recycled sheet, which comprises a step of forming a product into a sheet by pressing. 2. The cut piece 30 in the step (2).
The method for producing a recycled glass fiber reinforced plastic sheet according to claim 1, wherein -100 wt% and the original plate are heated together. 3. Heating and molding at least once using a plurality of glass fiber reinforced plastic recycled sheets obtained in claim 1 or 2, or a plurality of original sheets and recycled sheets. A method for producing a remolded product of glass fiber reinforced plastic, which is characterized.