KR100937231B1 - Manufacturing method of Fiber Reinforced Plastic forming goods - Google Patents

Abstract

The present invention relates to a method for producing a fiber-reinforced plastic molded article, comprising: (S1) combining a first long fiber having a predetermined melting point and a thermoplastic second long fiber having a lower melting point than the first long fiber to prepare a long filament; Making; (S2) cutting the laminated long fibers to a predetermined length to produce a plurality of molded composite raw materials made of the joined short fibers; And (S3) heating and molding the plurality of molded composite raw materials to a temperature higher than the melting point of the second long fiber and below the melting point of the first long fiber to produce a fiber-reinforced plastic molded article having a predetermined shape. According to the production method of the present invention, the short fibers can be well dispersed in the plastic molded body can improve the mechanical properties of the plastic molded body.

Fiber reinforced, plastic molded body, high dispersion

Description

Manufacturing method of fiber-reinforced plastic molded article {Manufacturing method of Fiber Reinforced Plastic forming goods}

The present invention relates to a method for producing a fiber-reinforced plastic molded article in which short fibers are dispersed in a resin, and more particularly, to a method for producing a fiber-reinforced plastic molded article in which short fibers are well dispersed in a plastic molded article.

The fiber-reinforced plastic molded body means a molded product in which a reinforcing material having a fiber shape is incorporated into a plastic material and then molded into a predetermined shape. Fibers dispersed in fiber-reinforced plastic moldings improve mechanical properties without significantly impairing the lightness of plastics. Fiber-reinforced plastic moldings are widely used in building materials such as electrical and electronic parts, sidewalk blocks, and mechanical parts. .

The plastic material of the fiber-reinforced plastic molded body is divided into a thermosetting material and a thermoplastic material. Fiber-reinforced plastic moldings obtained using thermosetting materials exhibit good stiffness and strength, especially good heat resistance and mechanical properties.Because the thermosetting process is irreversible, defective products cannot be recycled and should be disposed of, and the product is broken. . In particular, the molding process of the thermosetting plastic molded body is not suitable for modern high speed production technology because the mold must be kept closed until the curing process is completed.

Therefore, in spite of the advantages imparted to the molded article molded from the thermosetting material, the thermosetting material is replaced with the thermoplastic material.

The fiber-reinforced plastic molded article using a thermoplastic material is manufactured by heating and melting a thermoplastic material in a solid state at room temperature, and then mixing short fibers as a reinforcing material and then cooling. That is, the thermoplastic material is melted in a kneading apparatus such as a single screw or twin screw extruder, a roller mixer, mixed with short fibers, and then extruded or cast into a desired shape, followed by cooling. In the conventional method of manufacturing a fiber-reinforced plastic molded body, it is possible to produce a molded body having desirable mechanical properties only when the short fibers as reinforcement materials are uniformly mixed in the molten thermoplastic material. However, the short fibers as the reinforcing material differ from the specific gravity of the thermoplastic material, and it is not easy to uniformly disperse them in the thermoplastic material due to the characteristics of the fibrous shape. Accordingly, there is a problem in that the short fibers are agglomerated with each other and the mechanical properties of the plastic molded body are lowered.

Therefore, the technical problem to be achieved by the present invention is to provide a method for producing a fiber-reinforced plastic molded article that can shortly disperse the short fibers in the plastic molded article to improve the mechanical properties of the plastic molded article.

In order to achieve the above technical problem, the manufacturing method of the fiber-reinforced plastic molded article of the present invention,

(S1) preparing a long filament by combining the first long fiber having a predetermined melting point and the thermoplastic second long fiber having a lower melting point than the first long fiber;

(S2) cutting the laminated long fibers to a predetermined length to produce a plurality of molded composite raw materials made of the joined short fibers; And

(S3) heating and molding the plurality of molded composite raw materials to a temperature higher than the melting point of the second long fiber and lower than the melting point of the first long fiber to produce a fiber-reinforced plastic molded article having a predetermined shape.

According to another aspect of the present invention, the manufacturing method of the present invention,

(S1) preparing a composite long fiber by composite spinning a thermoplastic first polymer having a predetermined melting point and a thermoplastic second polymer having a lower melting point than the first polymer;

(S2) cutting the composite long fibers to a predetermined length to produce a plurality of molded composite materials made of composite short fibers; And

(S3) heating and molding the plurality of molded composite raw materials to a temperature higher than the melting point of the second polymer and lower than the melting point of the first polymer to produce a fiber-reinforced plastic molded article having a predetermined shape.

According to another aspect of the present invention, the manufacturing method of the present invention,

(S1) preparing a composite waste fabric woven from a first fiber having a predetermined melting point and a thermoplastic second fiber having a melting point lower than that of the first fiber;

(S2) pulverizing the composite waste fabric to a predetermined size to produce a plurality of molded composite raw materials; And

(S3) heating and molding the plurality of molded composite raw materials to a temperature higher than the melting point of the second fiber and below the melting point of the first fiber to produce a fiber-reinforced plastic molded article of a predetermined shape.

According to another aspect of the present invention, the manufacturing method of the present invention,

(S1) The composite waste fabric woven from coated fibers having a melting point lower than that of the first fiber on the surface of the first fiber having a predetermined melting point, or the surface of the fabric woven from the first fiber having a predetermined melting point. Preparing a composite waste fabric having a thermoplastic coating layer having a lower melting point than the first fiber;

(S2) pulverizing the composite waste fabric to a predetermined size to produce a plurality of molded composite raw materials; And

(S3) heating and molding the plurality of molded composite raw materials to a temperature higher than the melting point of the coating layer and lower than the melting point of the first fiber to produce a fiber-reinforced plastic molded article having a predetermined shape.

According to another aspect of the present invention, the manufacturing method of the present invention,

(S1) preparing a composite waste fabric having a thermoplastic sheet having a melting point lower than that of the first fiber on a fabric surface woven from a first fiber having a predetermined melting point;

(S2) pulverizing the composite waste fabric to a predetermined size to produce a plurality of molded composite raw materials; And

(S3) heating and molding the plurality of molded composite raw materials to a temperature higher than the melting point of the sheet and lower than the melting point of the first island, to produce a fiber-reinforced plastic molded article having a predetermined shape.

The method for producing a fiber-reinforced plastic molded article of the present invention first prepares a molded composite raw material of a predetermined size in which a thermoplastic material, which is a matrix material, and short fibers having a higher melting point than the thermoplastic material is first prepared, and then, they are separated between the thermoplastic material and the melting points of the short fibers. Heating and molding increased the dispersibility of the short fibers in the thermoplastic material in the fiber reinforced plastic molded body. That is, short fibers as a reinforcing material were prepared in pieces of a predetermined size (molded composite material) mixed with a thermoplastic material in advance, and the short fibers were previously dispersed in a molding raw material, and the thermoplastic material was melted to prepare a molded body by manufacturing a molded body. It was possible to improve mechanical properties by increasing the dispersibility of the short fibers in the molded body.

Hereinafter, the manufacturing method of the fiber reinforced plastic molded object which concerns on this invention is demonstrated in detail. On the other hand, in the present specification, "thermoplasticity" refers to a property that can be melted when formed by heating, and "melting point" should be interpreted to include not only melting point of the material but also thermal decomposition temperature as an expression for convenience of avoiding repetition.

As described above, in the conventional method of manufacturing a fiber-reinforced plastic molded body, the short fibers as reinforcement materials have a specific gravity different from that of the thermoplastic material, and are not easily dispersed uniformly in the molten thermoplastic material due to the characteristics of the fiber shape. Accordingly, there is a problem that short fibers are aggregated with each other in the molten thermoplastic material, thereby deteriorating mechanical properties of the plastic molded body.

In order to solve such a problem, the method of manufacturing a fiber-reinforced plastic molded article of the present invention first prepares a molded composite raw material of a predetermined size mixed with a thermoplastic material that is a matrix material and short fibers having a higher melting point than the thermoplastic material, and then thermoplastic It is characterized by increasing the dispersibility of the short fibers in the thermoplastic material by heating and molding them between the material and the melting points of the short fibers. That is, when the short fibers, which are reinforcing materials, prepare a section having a predetermined size (molded composite raw material) mixed with the thermoplastic material in advance, and then manufacture a molded body using the same, the short fibers are pre-dispersed in the molding raw material so that the thermoplastic material is formed during the molding process. When melting, the dispersibility of the short fibers is increased.

In the method for producing a fiber-reinforced plastic molded article of the present invention, a method for preparing a molded composite raw material may be adopted as follows.

(1) A laminated long fiber is prepared by combining a first long fiber having a predetermined melting point and a thermoplastic second long fiber having a lower melting point than the first long fiber. The first long filament and the second long filament may be manufactured according to a conventional filament yarn manufacturing method, and the filament may also combine the first filament and the second filament using a known fusing device. The second long fiber is made of a polymer having thermoplasticity and is a matrix material of a fiber-reinforced plastic molded body. The first long fiber is cut into short fibers in a later process to serve as a reinforcement material for the fiber-reinforced plastic molded body, and a material that melts or decomposes at a temperature higher than the melting point of the second long fiber, that is, a thermoplastic material as well as a thermosetting material, can be used. Do. However, in case of using thermosetting material, melting point of first long fiber should be interpreted as decomposition temperature. Within the range that satisfies the above requirements, the first long fiber may be metallized glass fiber, glass fiber such as E-glass fiber, ceramic fiber, graphite fiber, nickel coated graphite fiber, polyamide fiber, polyester fiber, or the like. Can be. Further, the first long fiber and the second long fiber may be, for example, polyethylene, ultra high molecular weight polyethylene, high density polyethylene, linear low density polyethylene, polypropylene, polycarbonate, polyolefin resin such as ethylene / acrylic acid copolymer, nylon 6 and nylon Polyamide-based polymers such as 66, phenylene oxide resin, phenylene sulfide resin, polyoxymethylene, polyester, ABS resin, polyvinyl chloride, vinylidene chloride / vinyl chloride resin, polyether ether ketone, polysulfur, polyether Thermoplastic resins such as mead, polystyrene, polyvinyl naphthalene, and the like may be used in combination, of course, thermoplastic resins should be adopted so that the melting point of the first long fiber is higher than that of the second long fiber.

Cutting the combined long fibers to a predetermined length yields a plurality of short fibers in a state in which the first long fibers and the second are combined, which are molded composite raw materials for obtaining a fiber-reinforced plastic molded body.

(2) According to another aspect of the method for producing a fiber-reinforced plastic molded article of the present invention, the following method may be adopted as a method for preparing a molded composite raw material.

A composite long fiber is prepared by composite spinning a thermoplastic first polymer having a predetermined melting point and a thermoplastic second polymer having a melting point lower than that of the first polymer. The composite spinning includes not only the composite spinning used for the production of the divided yarn such as the side by side type, but also all the composite spinning capable of producing two-component composite fibers such as sea island yarn. The thermoplastic first polymer and the thermoplastic second polymer may be adopted by combining the thermoplastic resins exemplified above as long as they are capable of complex spinning.

When the prepared long filaments are cut to a predetermined length, a plurality of short fibers in a state in which the thermoplastic first polymer and the thermoplastic second polymer are combined can be obtained, and these are molded composite raw materials for obtaining a fiber-reinforced plastic molded body.

(3) According to another aspect of the method for producing a fiber-reinforced plastic molded article of the present invention, the following method may be adopted as a method for preparing a molded composite raw material.

A composite waste fabric woven from a first fiber having a predetermined melting point and a thermoplastic second fiber having a melting point lower than the first fiber is prepared. As the composite waste fabric woven from the first and second fibers, for example, the first fiber (short fiber) and the second fiber (short fiber) are woven into a spun yarn interwoven, or each of the first fiber (a warp and weft yarn) Waste of woven fabrics woven using long or short fibers of spun yarn) and second fibers (spun yarn of long or short fibers). The second fiber is made of a polymer having thermoplasticity and is a matrix material of a fiber-reinforced plastic molded body. The first fiber is cut (grinded) in a later process to serve as a reinforcement material of the fiber-reinforced plastic molded body, and a material that melts or decomposes at a temperature higher than the melting point of the second fiber, that is, a thermoplastic material as well as a thermosetting material may be used. However, when using a thermosetting material, the melting point of the first fiber should be interpreted as the decomposition temperature. The materials usable as the first fibers and the second fibers correspond to the materials usable as the first long fibers and the second long fibers, respectively. Since the composite waste fabric is difficult to recycle and is disposed of by incineration or landfill, it is expected to be of great help in environmental protection if it is manufactured and recycled into a fiber-reinforced plastic molded body according to the manufacturing method of the present invention.

When the prepared composite waste fabric is ground to a predetermined size using an appropriate mill, a plurality of fragments in which the first fiber and the second fiber are present at the same time can be obtained, and these are molded composite raw materials for obtaining a fiber-reinforced plastic molded body.

(4) According to another aspect of the method for producing a fiber-reinforced plastic molded article of the present invention, the following method may also be adopted as a method for preparing a molded composite raw material.

The first fiber on the surface of the first textile having a predetermined melting point, or a composite waste fabric woven from coated fibers having a thermoplastic coating layer having a lower melting point than that of the first fiber, or a textile surface woven from the first fiber having a predetermined melting point A composite waste fabric is prepared in which a thermoplastic coating layer having a lower melting point is formed. Composite waste fabrics woven from coated fibers having a coating layer formed on the first fiber surface include, for example, various protective nets, geogrids, and tarpaulins in the form of fabrics woven from coated fibers having a polyvinyl chloride coating layer formed on polyester fibers or glass fibers. Although these etc. are mentioned, it is not limited to this. The coating layer is thermoplastic and is made of a matrix material of a fiber reinforced plastic molded article. The first fiber is cut (pulverized) in a later process to serve as a reinforcement material of the fiber-reinforced plastic molded body, and a material that melts or decomposes at a temperature higher than the melting point of the coating layer, that is, a thermoplastic material as well as a thermosetting material may be used. However, when using a thermosetting material, the melting point of the first fiber should be interpreted as the decomposition temperature. The materials usable as the first fiber and the coating layer correspond to the materials usable for the first long fiber and the second long fiber, respectively. Here, the composite waste fabric woven from the coated fiber having the coating layer formed on the first fiber is formed of the first fiber, and then the waste fabric woven using the first fiber, and the woven fabric using the first fiber, and then the coating layer on the surface of the fabric It should be interpreted to include all the waste fabrics formed.

When the prepared composite waste fabric is pulverized to a predetermined size using an appropriate mill, a plurality of fragments of coated fibers coated with a second fiber on the surface of the first fiber can be obtained, and these are molded composite raw materials for obtaining a fiber-reinforced plastic molded body. .

(5) According to another aspect of the method for producing a fiber-reinforced plastic molded article of the present invention, the following method may be adopted as a method for preparing a molded composite raw material.

A composite waste fabric with a thermoplastic sheet having a lower melting point than that of the first fiber is prepared on a fabric surface woven with a first fiber having a predetermined melting point. Such composite waste fabrics include, for example, woven fabrics with polyvinyl chloride sheets attached to woven fabrics of polyester fibers. The sheet is thermoplastic and is a matrix material of a fiber reinforced plastic molded body. The first fiber is cut (grinded) in a later process to serve as a reinforcing material of the fiber-reinforced plastic molded body, and a material that melts or decomposes at a temperature higher than the melting point of the coating layer, that is, a thermoplastic material as well as a thermosetting material may be used. However, when using a thermosetting material, the melting point of the first fiber should be interpreted as the decomposition temperature. The materials usable as the first fibers and the sheets correspond to the materials usable for the first long fibers and the second long fibers, respectively.

When the prepared composite waste fabric is crushed to a predetermined size using an appropriate grinder, a plurality of composite fragments having sheet fragments attached to the fabric fragments woven from the first fiber can be obtained. do.

Molded composite raw materials prepared according to the above-described method is a thermoplastic material (corresponding to thermoplastic second long fiber, thermoplastic second polymer, thermoplastic second fiber, thermoplastic coating layer, thermoplastic sheet) according to a conventional conventional fiber-reinforced plastic molding method A fiber-reinforced plastic molded article of desired desired shape is produced by heating and molding to a temperature higher than the melting point of and lower than the melting point of the short fibers of the reinforcing material (corresponding to the first long fiber, the thermoplastic first polymer and the first fiber).

Optionally, prior to forming the fiber-reinforced plastic molding, the molded composite raw materials are higher than the melting point of the thermoplastic material (corresponding to the thermoplastic second long fiber, the thermoplastic second polymer, the thermoplastic second fiber, the thermoplastic coating layer, the thermoplastic sheet) and the reinforcement material. The intermediate step of producing a chip shape by heating and molding to a temperature lower than the melting point of the short fibers (corresponding to the first long fiber, the thermoplastic first polymer, and the first fiber) may be further performed.

In addition, depending on the ratio of the matrix resin of the fiber-reinforced plastic molded product finally desired, a separate thermoplastic material (Chip) may be further added to the molded composite raw material before molding the fiber-reinforced plastic molded product.

On the other hand, when producing a fiber-reinforced plastic molded article such as a sidewalk block, it is preferable to further add a blowing agent to the molded composite raw material before the heating and forming step. As the blowing agent, a gas such as carbon dioxide, argon, neon, nitrogen, oxygen, or a low boiling point hydrocarbon blowing agent such as a halogenated hydrocarbon blowing agent may be used. In addition, carbonate, bicarbonate, nitrate, alkali borohydride, peroxide, Chemical blowing agents such as urea and azo compounds may be used, but are not limited thereto. By using a blowing agent, a low density fiber reinforced plastic molded object can be manufactured.

Further, within the scope of not impairing the object of the present invention, fillers such as silicon dioxide, calcium carbonate, magnesium oxide, pulp, calcium silicate, mica, color expression materials such as pigments and dyes can be added, antioxidants, Other additives such as UV stabilizers, thickeners, antifoaming agents, antibacterial agents and the like may be added.

Hereinafter, the present invention will be described in detail with reference to Examples. However, embodiments according to the present invention can be modified in many different forms, the scope of the present invention should not be construed as limited to the embodiments described below. Embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

Example 1

1000 denier polyester high-strength yarn 1000denier of 9g / den was spun and twisted with polypropylene 1000denier and 60 T / M, and then cut at 15 mm intervals to form a short fiber shape. The prepared short fibers were introduced into an extruder, extruded under conditions of a temperature of 160 degrees and a residence time of about 25 seconds, and palletized to form chips.

The cross section was examined by cutting the chip shape in the longitudinal direction, and the chip was melt-molded to make a block having a height of 10 cm in width and length, and the compressive strength and the cutting strength were measured. Table 1 outlines the cross section of the chip and the physical properties of the block.

Example 2

Polyvinyl chloride-based resin was melt-extruded, and the polyester high-strength yarn 1000 denier having a strength of 9 g / den was sand coated with a thickness of 0.5 mm, and cut at 15 mm intervals to form a short fiber shape. The prepared short fibers were introduced into an extruder, extruded under conditions of a temperature of 190 degrees and a residence time of about 25 seconds, and palletized to form chips.

The cross section was examined by cutting the chip shape in the longitudinal direction, and the chip was melt-molded to make a block having a height of 10 cm in width and length, and the compressive strength and the cutting strength were measured. Table 1 outlines the cross section of the chip and the physical properties of the block.

Comparative Example 1

The polypropylene resin was dispersed and blended with 1000denier polyester high-strength yarn 1000dener having a strength of 9g / den cut in the form of short fiber of 15mm length, and then extruded under the conditions of 190 degree temperature and 25 second residence time by feeding it to an extruder. Palletized to form a chip.

The cross section was examined by cutting the chip shape in the longitudinal direction, and the chip was melt-molded to make a block having a height of 10 cm in width and length, and the compressive strength and the cutting strength were measured. Table 1 outlines the cross section of the chip and the physical properties of the block.

Comparative Example 2

The polyvinyl chloride-based resin having a plasticizer content of 30% was dispersed and blended with a polyester high-strength yarn 1000denier having a strength of 9g / den cut in the form of short fibers having a length of 15mm, and then introduced into an extruder, and the temperature was 190 degrees and a residence time was about 25 seconds. Extruded under the condition of, it was palletized into a chip shape.

The cross section was examined by cutting the chip shape in the longitudinal direction, and the chip was melt-molded to make a block having a height of 10 cm in width and length, and the compressive strength and the cutting strength were measured. Table 1 outlines the cross section of the chip and the physical properties of the block.

Claims (8)

delete delete (S1) preparing a composite waste fabric woven from a first fiber having a predetermined melting point and a thermoplastic second fiber having a melting point lower than that of the first fiber; (S2) pulverizing the composite waste fabric to a predetermined size to produce a plurality of molded composite raw materials; (S3) preparing a plurality of chips by inserting the plurality of molded composite raw materials into an extruder, and then heating and extruding to a temperature higher than the melting point of the second fiber and below the melting point of the first fiber; And (S4) The method of manufacturing a fiber-reinforced plastic molded article comprising the step of heating and molding the chips to a temperature higher than the melting point of the second fiber and lower than the melting point of the first fiber to produce a fiber-reinforced plastic molded article of a predetermined shape. (S1) The composite waste fabric woven from coated fibers having a melting point lower than that of the first fiber on the surface of the first fiber having a predetermined melting point, or the surface of the fabric woven from the first fiber having a predetermined melting point. Preparing a composite waste fabric having a thermoplastic coating layer having a lower melting point than the first fiber; (S2) pulverizing the composite waste fabric to a predetermined size to produce a plurality of molded composite raw materials; (S3) preparing a plurality of chips by inserting the plurality of molded composite raw materials into an extruder, and then heating and extruding to a temperature higher than the melting point of the coating layer and below the melting point of the first fiber; And (S4) The method of manufacturing a fiber-reinforced plastic molded article comprising the step of heating and molding the chips to a temperature higher than the melting point of the coating layer and lower than the melting point of the first fiber to produce a fiber-reinforced plastic molded article of a predetermined shape. (S1) preparing a composite waste fabric having a thermoplastic sheet having a melting point lower than that of the first fiber on a fabric surface woven from a first fiber having a predetermined melting point; (S2) pulverizing the composite waste fabric to a predetermined size to produce a plurality of molded composite raw materials; (S3) preparing a plurality of chips by inserting the plurality of molded composite raw materials into an extruder, and then heating and extruding to a temperature higher than the melting point of the sheet and below the melting point of the first fiber; And (S4) The method of manufacturing a fiber-reinforced plastic molded article comprising the step of heating and molding the chips to a temperature higher than the melting point of the sheet and lower than the melting point of the first fiber to produce a fiber-reinforced plastic molded article of a predetermined shape. The method for producing a fiber-reinforced plastic molded article according to any one of claims 3 to 5, wherein a foaming agent is further added during the heating and molding of the step (S4). The method of claim 4, wherein the first fiber is a polyester fiber, and the thermoplastic coating layer is made of polyvinyl chloride. The method of claim 5, wherein the first fiber is a polyester fiber, and the thermoplastic sheet is made of polyvinyl chloride.