JP2006096966A - Long fiber-reinforced thermoplastic resin structure, its molding and production method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a resin structure that comprises a metal long fiber, raises physical strength and is applied to a molding. <P>SOLUTION: The long fiber-reinforced thermoplastic resin structure comprises 2-45 wt.% of a metal fiber and 10-60 wt.% of at least another kind of a fiber in which the fiber length of both the fibers is 3-100 mm and the fibers are arranged approximately in parallel. The metal fiber and at least one kind of the fiber are opened while being drawn and impregnated with a thermoplastic resin in a molten state. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a thermoplastic resin structure reinforced with a composite fiber of metal fibers and other fibers, a manufacturing method thereof, a molded body thereof, and a manufacturing method thereof.

  The long fiber reinforced thermoplastic resin structure has greatly improved the physical properties of the thermoplastic resin by effectively impregnating the long fiber with the resin, and has dramatically expanded the range of use as the resin. As described in JP-A-3-181528, the long fiber reinforced thermoplastic resin structure is opened while drawing a fiber bundle, impregnated with a molten thermoplastic resin, shaped, and excess resin is formed. Except for cooling, it is obtained by cutting to an appropriate length after cooling. This publication also describes the reason why it is important to impregnate the fiber with a suitable sizing agent before impregnating the resin.

  Japanese Patent Application Laid-Open No. 2004-14990 proposes application of a long metal fiber-containing resin to an electromagnetic wave shielding resin. As shown therein, it is also shown that the metal fiber contained in the resin is a long fiber and has a strong electromagnetic shielding effect. Resins that exhibit electromagnetic shielding effects are strongly demanded for resinization of containers aimed at reducing the weight of digital products such as mobile PCs and mobile phones. Resins exhibiting electromagnetic shielding effects and strength comparable to metals Is waiting for development.

  However, regarding the sizing treatment of metal fibers, at present, industrial production of metal fibers subjected to sizing treatment has not been performed due to cost and technical problems. The use of metal fiber bundles that have not been sized for the production of long fiber reinforced resin structures is because glass resin bundles that have been subjected to sizing treatment cannot be used because the molten resin cannot strongly adsorb fibers. Compared with the case where it had, physical strength as a resin cannot be raised.

Therefore, attempts have been made to mix long metal fiber pellets impregnated with resin and long fiber reinforced resin pellets such as glass. When a product is melted in a hopper such as an extruder, metal fiber resin pellets with high specific gravity are unevenly distributed at the bottom, and resin pellets with light specific gravity and long glass fiber reinforced resin pellets are unevenly distributed at the top and extruded from the extruder. At this stage, it is not possible to obtain a molded body in which both fibers are uniformly dispersed.
JP-A-3-181528 JP 2004-14990 A

  An object of the present invention is to provide a resin structure containing a long metal fiber, to increase its physical strength, and to enable application to a molded body.

  As a result of intensive studies, the present inventor has made a long fiber reinforced thermoplastic resin structure adapted to the above purpose by impregnating a resin under specialized conditions while simultaneously drawing metal long fibers and other long fibers. The present invention was completed.

  That is, the object of the present invention is that the metal fiber is 2 to 45% by weight, at least one other kind of fiber is 10 to 60% by weight, each fiber has a fiber length of 3 to 100 mm, and substantially parallel. A long fiber reinforced thermoplastic resin structure is provided.

  Further, an object of the present invention is to provide the long fiber reinforced thermoplastic resin structure as described above, wherein the fiber fiber is opened while drawing at least one other fiber and impregnated with a thermoplastic resin in a molten state. provide.

  Another object of the present invention is to provide the long fiber reinforced thermoplastic resin structure as described above, wherein at least one other fiber is a glass fiber.

  Still another object of the present invention is to provide a long fiber reinforced thermoplastic resin molded article formed from a material containing at least the long fiber reinforced thermoplastic resin structure described above.

  Another object of the present invention is to provide metal fibers and at least one other fiber with different tensions so that the opening widths of the respective fibers are approximately the same. And a method for producing a long-fiber reinforced thermoplastic resin structure in which at least one other type of fiber is contained in an amount of 10 to 60% by weight, each fiber has a fiber length of 3 to 100 mm, and is arranged substantially in parallel. To do.

  Further, the object of the present invention is to provide a method for producing a long fiber reinforced thermoplastic resin structure as described above, wherein the fiber width of the metal fiber and at least one other fiber is 5 to 50 mm. I will provide a.

  Moreover, the objective of this invention provides the shaping | molding method of the long fiber reinforced thermoplastic resin molded object using the material which contains the long fiber reinforced thermoplastic resin structure as described above at least.

Still another object of the present invention is to provide a method for molding a long fiber reinforced thermoplastic resin molding as described above, wherein the back pressure of a screw of an extruder or the like used for molding is 10 kg / cm ² or less. provide.

  According to the present invention, the physical strength of the long fiber reinforced thermoplastic resin structure is increased by impregnating the resin under specialized conditions while simultaneously drawing the metal long fiber and other long fibers, It can be applied to molded products, and can reduce the weight of housings for digital products.

  As a metal fiber used by this invention, the 1 type (s) or 2 or more types chosen from stainless steel fiber, aluminum fiber, nickel fiber, copper fiber, and brass fiber is mentioned, Especially, stainless steel fiber is preferable.

  Other fibers other than metals are not limited to the fibers listed below as long as the fibers have a higher modulus of elasticity than the matrix resin used, and any known fiber can be used as the reinforcing fiber. . For example, glass fibers such as E-glass and D-glass; carbon fibers such as polyacrylonitrile, pitch and rayon; inorganic fibers such as boron fibers and mineral fibers; ultrahigh molecular weight polyethylene fibers, polyoxymethylene fibers, polyvinyls Organics such as alcohol fibers, liquid crystalline aromatic polyester fibers, polyethylene terephthalate fibers, poly-p-phenylene terephthalamide fibers, aramid fibers such as poly-m-phenylene isophthalamide fibers, polyacrylonitrile fibers, cellulose fibers such as cotton and jute Examples include fibers. Particularly preferred fibers to which the present invention is applied are glass fibers or organic fibers.

  The content of the metal fiber in the long fiber reinforced thermoplastic resin structure is 2 to 45% by weight, preferably 3 to 40% by weight, particularly preferably 5 to 30% by weight. When the content is less than 2% by weight, the electromagnetic shielding effect cannot be obtained. When the content is more than 45% by weight, the specific gravity increases and the resin pellets are separated and mixed with other resin pellets.

  The content of other fibers, such as glass fibers, is 10 to 60% by weight, preferably 15 to 50% by weight, and particularly preferably 20 to 45% by weight. If the amount is less than 10% by weight, the physical strength as a resin cannot be sufficiently obtained. If the amount exceeds 60% by weight, the total amount of metal fibers exceeds 60% by weight, resulting in a low resin content. It is sufficient and sufficient impregnation is not possible and the physical strength of the structure is insufficient.

  The fiber length of the long fibers contained in the long fiber reinforced thermoplastic resin structure is 3 to 100 mm, preferably 5 to 80 mm, and particularly preferably 7 to 50 mm. If it is 3 mm or less, the fibers are further cut at the stage of forming a molded body, and therefore, the physical strength peculiar to long fibers cannot be obtained. On the other hand, if the length is longer than 100 mm, it may become difficult to mix by handling to an extruder or the like at the time of molding, which may cause inconvenience.

  The long fiber reinforced thermoplastic resin of the present invention also proposes a method of impregnating two or more types of fibers simultaneously with resin, in particular, for simultaneously impregnating other fibers typified by metal fibers and glass fibers. It is necessary to set a situation where metal fibers and other fibers are easily impregnated with resin to the same extent. For the first time, the purpose could be achieved by making the tension roll double, and in order to open each fiber to the same extent, appropriate tension can be applied to each. When the opening state of each fiber is represented by the opening width, it is usually 5 to 50 mm, preferably 10 to 45 mm, and particularly preferably 15 to 40 mm. If the spread width is less than 5 mm, the resin cannot be sufficiently impregnated. If the spread width exceeds 50 mm, the tension may be too high and the fiber may be cut.

  As long as the matrix resin of the long fiber reinforced thermoplastic resin pellet used in the present invention is a thermoplastic resin, all resins can be used. For example, general-purpose polystyrene, impact-resistant polystyrene, acrylonitrile-styrene copolymer resin, polystyrene resin such as acrylonitrile-butadiene-styrene copolymer resin, polyolefin resin such as polyethylene and polypropylene, polyethylene terephthalate, polybutylene terephthalate, etc. Thermoplastic polyester resins, polycarbonate resins, halogen-containing polyolefin resins such as vinyl chloride and chlorinated polypropylene, polyamide resins such as nylon 6, nylon 66, nylon 46, nylon 11 and nylon 12, polyethyl acrylate resins, poly Polyacrylic resin such as methyl methacrylate resin, polysulfonic acid resin, polyphenyl ether resin, polyacetal resin, liquid crystalline aromatic polyester resin, poly E double sulfide resins, all thermoplastic resin and alloy resin composed of two or more of these general-purpose resins such as polyether ether ketone resin until super engineering plastics can be used. The resin forming the alloy is not limited to the thermoplastic resins listed here, and other well-known thermoplastic resins and two or more types of these alloys can be used. Particularly preferable thermoplastic resins to which the present invention is applied include inexpensive polystyrene resins, polyolefin resins, halogen-containing polyolefin resins, and nylon resins. Moreover, what mixed two or more types of above-mentioned resin is also useful.

  Further, in order to impart desired properties according to the purpose, known substances generally added to thermoplastic resins, for example, stabilizers such as antioxidants, heat stabilizers, ultraviolet absorbers, antistatic agents, flame retardants, It is also possible to blend flame retardant aids, colorants such as dyes and pigments, lubricants, plasticizers, crystallization accelerators, crystal nucleating agents and the like. Further, glass flakes, mica, glass powder, glass beads, talc, clay, alumina, carbon black, wollastonite and other plate-like or powdery inorganic compounds, whiskers and the like may be used in combination.

  Further, in molding the long fiber reinforced thermoplastic resin structure of the present invention, the molding methods include extrusion molding, injection molding, blow molding, extrusion blow molding, injection blow molding, inflation molding, stamping molding, compression molding, and beads. Examples include molding. Of these, injection molding is preferred.

In the long fiber reinforced thermoplastic resin structure of the present invention, the pellets are already mixed and impregnated with metal fibers and other fibers, such as glass fibers, so that melt mixing in the molding stage can be performed under mild conditions. Therefore, it is possible to prevent shortening of fibers due to unnecessary fiber cutting, and it is advantageous that the electromagnetic wave shielding effect and the resin are sufficiently strengthened. In order to mix and mold metal fiber-containing pellets and other fibers, for example, reinforcing fiber-containing pellets such as glass, sufficient mixing is required with a mixer, and it becomes difficult to achieve the purpose by shortening the fibers. For example, as a condition for molding using the long fiber reinforced thermoplastic resin structure of the present invention, a screw type extruder or the like is usually used, and the back pressure serving as an index of the stirring strength is 10 kg / cm ^2. It is sufficient to carry out the following, preferably 5 kg / cm ² , particularly preferably 0 kg / cm ² . Thereby, the average fiber length in a molded object was able to be 2 mm.

In mixed molding of metal fiber-containing pellets and other fibers such as glass or other reinforcing fiber-containing pellets, the back pressure of the screw needs to be higher than 10 kg / cm ² , and as a result, the average fiber length is less than 1 mm. Absent.

Hereinafter, the present invention will be described in detail based on examples, but the present invention is not limited to the examples.
[Example fibers used]
Glass reinforced fiber: A sizing treatment of a bundle of 4000 single glass fibers having a diameter of 17 μm.
Stainless steel fiber; in the examples, a bundle of 1000 stainless steel fibers having a diameter of 11 μm. In a comparative example, a fiber bundle of 7000 stainless single fibers having a diameter of 11 μm. Neither is sizing. Normally, 7000 fiber bundles are commercially available, but 1000 were produced on a trial basis in carrying out the present invention.
Example 1

  A long fiber reinforced thermoplastic resin structure manufacturing apparatus having a structure as shown in FIG. 1 was used. The stainless steel fiber roving was guided from the cake-wrapped stainless steel fiber bundle 1 (fiber bundle of 1000 stainless single fibers having a diameter of 11 μm) to the crosshead die 6 through the tension roll 3. Similarly, the glass fiber roving was guided from the cake-wrapped glass reinforcing fiber bundle 2 (which was sized to a bundle of 4000 single glass fibers having a diameter of 17 μm) to the crosshead die 6 through the tension roll 4. Stainless fiber roving is tensioned with a tension roll so that the opening width is about 20 mm, and glass fiber roving is tensioned with a tension roll so that the opening width is about 20 mm. ) It led to the entrance of the crosshead die so as to pile up one by one. Each fiber roving was carried out so that there were four rovings and four rovings impregnated with resin. The nylon 66 resin to be impregnated was supplied from the resin supply port 5 to the crosshead die in a molten state using an extruder. After both fibers joined at the crosshead die inlet are impregnated with resin inside the crosshead die, excess resin is squeezed out by the shaping die 7 so that the fiber content becomes 50% by weight. After being cooled with cold air at 8, it was cut into a length of about 12 mm by a pelletizer 10 through a take-up machine 9. The obtained long fiber reinforced resin structure (pellet) had a stainless fiber content of 13% by weight and a glass fiber content of 37% by weight.

46 parts by weight of the long fiber reinforced resin structure obtained above and 54 parts by weight of the nylon 66 pellets used above were mixed in a blender until the composition was uniform, charged into an extruder equipped with a hopper, and injected. A molded body was prepared by molding. This long fiber reinforced resin molded product had a stainless fiber content of 6% by weight and a glass fiber content of 17% by weight, and the fiber content ratio was constant even after repeated molding.
(Comparative Example 1)

  In the apparatus shown in FIG. 2, a stainless fiber resin structure and a glass fiber reinforced resin structure were separately manufactured. However, as the stainless steel fiber bundle, a fiber bundle of 7000 stainless steel single fibers having a diameter of 11 μm was used. A nylon 66 resin pellet having a stainless fiber content of 50% by weight and a nylon 66 resin pellet having a glass fiber content of 50% by weight were obtained.

In order to obtain a molded product having the same composition as in Example 1, 12 parts by weight of nylon 66 resin pellets having a stainless fiber content of 50% by weight and 34 parts by weight of nylon 66 resin pellets having a glass fiber content of 50% by weight were prepared. 54 parts by weight of nylon 66 resin pellets were mixed with a blender until the composition became uniform, and a molded body was prepared by injection molding using an extruder in the same manner as in Example 1. Variations were seen. In order to follow the respective phenomena at the time of injection molding in Example 1 and Comparative Example 1, the following evaluation tests were tried.
(Evaluation test)

25 kg of pellets having the composition shown in Table 1 are put into a 50-liter hopper equipped with a screw-type quantitative feeder at the bottom, and the quantitative feeder is driven, and the pellets discharged from the quantitative feeder are in the initial, middle and late stages. In three stages, three samples of 200 g each were sampled for a total of nine samples, and each sampled sample was divided into types of pellets, and the weight ratio of the pellets of each type was determined. The results are shown in Table 1. In the table, “mixed fiber” in the column of Example means pellets made of mixed fiber of stainless fiber and glass fiber prepared in Example 1, and in the column of Comparative Example, there are metal fiber and glass fiber. This means the stainless fiber pellets and glass fiber pellets prepared in Comparative Example 1. A numerical value shows weight% of each pellet, and has shown the average value measured by sampling 3 each. In Example 1, the ratio of the mixed fiber pellets was constant in the early, middle, and late stages of discharge, but in the comparative example, the stainless fiber pellets showed variations.

This is an apparatus in which an appropriate tension is applied to each fiber by different tension rolls from two types of fiber bundles, which is sent to a crosshead die and impregnated with molten resin therein. Although not denoted by reference numerals, FIG. 1 shows an ordinary apparatus for impregnating one kind of fiber as compared with the apparatus for treating two kinds of fibers.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Metal fiber bundle 2 Other fiber bundles 3 Tension roll 4 Tension roll 5 Molten resin inlet 6 Crosshead die 7 Shaping die 8 Cooling device 9 Take-out machine 10 Pelletizer

Claims (8)

  Metal fiber is 2 to 45% by weight, at least one other type of fiber is 10 to 60% by weight, each fiber has a fiber length of 3 to 100 mm, and long fiber reinforced thermoplastics arranged in parallel. Resin structure.   2. The long fiber reinforced thermoplastic resin structure according to claim 1, wherein the metal fiber and at least one other fiber are opened while being drawn, and the thermoplastic resin is impregnated in a molten state.   2. The long fiber reinforced thermoplastic resin structure according to claim 1, wherein the at least one other fiber is a glass fiber.   A long fiber reinforced thermoplastic resin molded article molded from a material containing at least the long fiber reinforced thermoplastic resin structure according to claim 1.   The metal fiber is characterized by applying different tensions to the metal fiber and at least one other fiber so that the opening width of each fiber is approximately the same, and is 2 to 45% by weight, and at least one other fiber A method for producing a long fiber reinforced thermoplastic resin structure comprising 10 to 60% by weight of any fiber, each fiber having a fiber length of 3 to 100 mm, and arranged substantially in parallel.   6. The method for producing a long fiber reinforced thermoplastic resin structure according to claim 5, wherein the fiber width of the metal fiber and at least one other fiber is 5 to 50 mm.   A method for molding a long fiber reinforced thermoplastic resin molded article using a material containing at least the long fiber reinforced thermoplastic resin structure according to claim 1. The method for molding a long fiber reinforced thermoplastic resin molded article according to claim 7, wherein the back pressure of a screw of an extruder or the like used for molding is 10 kg / cm ² or less.

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