JP2006045390A - Flat glass fiber-containing pellet, molded object of flat glass fiber-containing thermoplastic resin and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a raw material to obtain a molded object of a glass fiber-containing thermoplastic resin having superior tensile strength, superior impact strength and enhanced surface flatness. <P>SOLUTION: This flat glass fiber-containing pellet 100 comprises flat glass fiber filaments 20 of a flat cross section in a pellet 10 of a thermoplastic resin, in which the plurality of the filaments are arranged in one direction so that both end faces of the filaments come to surfaces of the pellet. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to flat glass fiber-containing pellets, flat glass fiber-containing thermoplastic resin moldings, and methods for producing them.

  Generally, a thermoplastic resin molding reinforced with glass fibers is obtained by melt-mixing glass fiber chopped strands obtained by bundling a plurality of glass fiber filaments and cutting them into a predetermined length together with thermoplastic resin pellets, and then subjecting the mixture to injection molding. Manufactured.

  However, in this manufacturing method, the glass fiber is often crushed during injection molding, the fiber length of the glass fiber remaining in the final product becomes extremely short, and the strength (tensile strength, etc.) and impact resistance are insufficient. It becomes. Further, the glass fiber filament may be oriented with the flow of the resin at the time of injection molding, so that the molded product may have directionality and warp may occur.

In order to solve such problems, instead of glass fiber chopped strands using glass fiber filaments having a circular cross section, flat glass fibers having a flat cross section are used, and this is mixed and melted with a thermoplastic resin and injection molded. A method has been proposed (Patent Document 1). In addition, the use of pellets cut after impregnating a long glass fiber with a thermoplastic resin has been studied (Patent Document 2).
Japanese Patent Publication No. 2-60494 JP-A-5-9380

  In the method described in Patent Document 1, it is true that the tensile strength is improved, the directionality of the molded product is prevented, and surface smoothness and warpage prevention are also effective. However, with regard to impact resistance (impact strength), if the type of thermoplastic resin used is changed, it may be reduced to the same extent as when glass fibers having a circular cross section are used. When the thermoplastic resin is a polyamide resin There is a problem that this phenomenon occurs remarkably. The reason for this is not clear, but due to the influence of the melt viscosity of the thermoplastic resin and the adhesiveness between the thermoplastic resin and the glass fiber filament, the balance between the fluidity and dispersibility of the fiber bundle in the thermoplastic resin at the time of molding. It is thought that it may collapse.

  On the other hand, the method described in Patent Document 2 can be expected to improve tensile strength and impact strength, but it is difficult to prevent warpage and improve surface smoothness.

  Therefore, even if a polyamide resin is used as a thermoplastic resin, the object of the present invention is not only excellent in tensile strength, but also excellent in impact strength, suppressed warpage, and improved surface smoothness. An object of the present invention is to provide a glass fiber-containing thermoplastic resin molding and a method for producing the same. Another object of the present invention is to provide a raw material containing glass fibers and a thermoplastic resin used for producing such a glass fiber-containing thermoplastic resin molding, and a method for producing the same.

  In order to achieve the above-mentioned object, the present invention arranges a plurality of flat glass fiber filaments having a flat cross section in a pellet made of a thermoplastic resin in one direction so that both end faces of the filament reach the pellet surface. A flat glass fiber-containing pellet is provided.

  When a glass fiber-containing thermoplastic resin molding is produced by injection molding using such flat glass fiber-containing pellets, it is possible to suppress the shortening of the glass fibers accompanying the glass fiber grinding during molding. As a result, not only the tensile strength but also the impact strength is improved, and the phenomenon that directionality occurs in the molded product is suppressed, warping is prevented, and the surface smoothness is also improved. Furthermore, the above effect is exhibited regardless of the type of thermoplastic resin, and stable characteristics can be obtained even for polyamide resins that have been difficult in the past.

  The flat glass fiber filaments have a fiber length of 2 to 50 mm, and the number of the flat glass fiber filaments arranged in the pellet is preferably 500 to 8000. By adopting such a configuration, the above effects can be remarkably exhibited.

  The above-mentioned flat glass fiber-containing pellet is a through-hole of a die in which a through hole is formed together with a thermoplastic resin obtained by hot-melting a fiber bundle in which a plurality of long flat glass fiber filaments having a flat cross section are arranged and arranged. It can be efficiently produced by a production method in which a fiber bundle attached with a thermoplastic resin obtained by drawing through a hole and cutting out is cut.

  Even when a polyamide resin is used as a thermoplastic resin, it is not only excellent in tensile strength, but also excellent in impact strength, suppressed warpage, and improved surface smoothness. Articles and methods for making the same are provided. Moreover, the raw material containing glass fiber and a thermoplastic resin used in order to manufacture such a glass fiber containing thermoplastic resin molding, and its manufacturing method are provided.

  Hereinafter, preferred embodiments of flat glass fiber-containing pellets, flat glass fiber-containing thermoplastic resin moldings, and production methods thereof will be described in detail with reference to the accompanying drawings. In addition, the same code | symbol shall be used for the same element and the overlapping description is abbreviate | omitted.

  FIG. 1 is a perspective view of a flat glass fiber-containing pellet according to the first embodiment, FIG. 2A is a front view of the flat glass fiber-containing pellet according to the embodiment, FIG. 1B is a side view thereof, and FIG. It is the same top view.

  As shown in FIG. 1 and FIGS. 2A to 2C, the flat glass fiber-containing pellet 100 according to the first embodiment includes a plurality of flat glass fiber filaments 20 in one direction in a pellet 10 made of a thermoplastic resin. Is arranged.

  As apparent from the side view of FIG. 2B, the cross section of the flat glass fiber filament 20 is flat (non-circular), and the end surface of the flat glass fiber filament 20 reaches the surface of the pellet 10. In FIG. 2 (b), only one side surface (end surface) is shown, but as can be seen from FIGS. 2 (a) and 2 (c), the flat glass fiber filament 20 is also formed on the surface of the other side surface (end surface). Has reached.

  The flat glass fiber-containing pellet 100 of the first embodiment has an elliptical columnar shape, has both end faces, and the cross-sectional shape is substantially the same along the longitudinal direction. However, the flat glass fiber-containing pellet of the present invention is not limited to such a shape, and various shapes such as a columnar shape can be employed.

  FIG. 3 shows flat glass fiber-containing pellets (flat glass fiber-containing pellets according to the second embodiment) having a shape different from that of the first embodiment, and FIGS. 3 (a), 3 (b) and ( c) are a front view, a side view and a plan view, respectively.

  A flat glass fiber-containing pellet 110 according to the second embodiment shown in FIGS. 3A to 3C is obtained by arranging a plurality of flat glass fiber filaments 20 in one direction in a pellet 10 made of a thermoplastic resin. Yes, both end faces of the flat glass fiber filament 20 reach the surface of the pellet 10. As shown in the figure, in the flat glass fiber-containing pellet 110, a cross section cut by a plane perpendicular to the longitudinal direction has an atypical cross-sectional shape different from a circular or elliptical shape. Moreover, the cross-sectional shape cut | disconnected along the longitudinal direction changes with cutting parts.

  As described above, the flat glass fiber-containing pellets of the present invention can have any external shape, but by using them for injection molding, in order to obtain a glass fiber-containing thermoplastic resin that is superior in tensile strength, impact strength, and surface smoothness. The following preferred conditions are preferably employed.

  For flat glass fiber filaments, the minor axis is 3 to 20 μm (further 4 to 15 μm), the major axis is 6 to 100 μm (further 15 to 80 μm), and the flatness is 2 to 10 (further 3 to 8). The thing of the range is suitable. Here, the “minor axis”, “major axis”, and “flatness” will be described with reference to FIG. As shown in FIG. 4, the “major axis” and “minor axis” are the length A (fiber cross section) of the long side Ra of the rectangle R assuming a rectangle R of the minimum area circumscribing the flat glass fiber filament 20. And the length B of the short side Rb. Further, the “flattening ratio” is indicated by a ratio (A / B) between the length of the long side and the length of the short side.

  The preferred short diameter of the cross section of the flat glass fiber filament 20 is 3 to 20 μm and the preferred long diameter is 6 to 100 μm for the following reason. That is, when a flat glass fiber filament whose minor axis is thinner than 3 μm or a flat glass fiber filament whose minor axis exceeds 20 μm is used, spinning is difficult or spinning efficiency is lowered. In particular, the strength of a molded product obtained by injection-molding pellets containing flat glass fiber filaments having a minor axis exceeding 20 μm may decrease. In addition, flat glass fiber filaments having a major axis of less than 6 μm and flat glass fiber filaments having a major axis of more than 100 μm are difficult to spin glass fiber filaments, and the spinning efficiency tends to be reduced. In particular, when the major axis exceeds 100 μm, the flattening efficiency is poor and the rigidity becomes high.

  The “flat” includes non-circular ones. For example, the flat glass fiber filament 20 has an elliptical cross-sectional shape and an elliptical shape having a straight portion in the major axis direction, as shown in the cross-sectional view of FIG. Such a glass fiber filament is included. In the present invention, when a plurality of flat glass fiber filaments are arranged in a pellet, the flat glass fiber filaments are easily arranged in an overlapping manner so that the long diameters of the flat glass fiber filaments are oriented in substantially the same direction. The same applies to the flat glass fiber filament 20 having a saddle-shaped cross section, and as shown in the cross-sectional view of FIG. 6, it is likely to be in an aggregated state in which the dent portion and the bulge portion are combined. The cross-sectional shape of the flat glass fiber filament can be appropriately selected according to the type of thermoplastic resin of the molded product and the required characteristics.

  The fiber length of the flat glass fiber filament 20 is preferably 2 to 50 mm, and more preferably 5 to 30 mm. When the fiber length of the flat glass fiber filament 20 is less than 2 mm, the degree to which the flat glass fiber-containing thermoplastic resin molded product to be produced is reinforced by the glass fiber may be low. When the fiber length exceeds 50 mm, the fiber length is Since it is too long, bridging is likely to occur in the supply hopper of the injection molding machine, the fluidity in the thermoplastic resin during molding becomes uneven, and molding failure may occur. In addition, since the both ends of the flat glass fiber filament 20 have reached the surface of the pellet 10, the fiber length of the flat glass fiber filament 20 and the pellet length of a flat glass fiber containing pellet become substantially equal. For example, when the fiber length of the flat glass fiber filament 20 is 10 mm, the pellet length of the flat glass fiber-containing pellet is approximately 10 mm.

  Examples of the glass constituting the flat glass fiber filament 20 include E glass, S glass, low dielectric glass, and C glass. E glass is preferred from the viewpoint of easy fiberization.

  The number of flat glass fiber filaments 20 contained in the flat glass fiber-containing pellet is preferably 500 to 8000, and more preferably 600 to 5000. When the number of flat glass fiber filaments 20 is less than 500, the production efficiency of pellets is reduced, and when the number of flat glass fiber filaments 20 exceeds 8000, the pellets become too thick and the pellets are produced. At times, troubles are likely to occur and the resin impregnation property may be reduced.

  The flat glass fiber-containing pellet has a suitable flat glass fiber filament content (hereinafter referred to as “glass content”). The glass content is preferably 10 to 60% by mass, more preferably 30 to 50% by mass, based on the total weight of the flat glass fiber-containing pellets. If the glass content is less than 10% by mass, the reinforcing effect by the glass fiber is not sufficient, and the strength of the molded product may be lowered. When glass content exceeds 60 mass%, resin impregnation property may fall and the intensity | strength of a molded product may fall.

  A sizing agent component may adhere to the periphery of the flat glass fiber filament 20 of the flat glass fiber-containing pellet (that is, the interface between the flat glass fiber filament and the thermoplastic resin). This sizing agent is used when producing a fiber bundle in which a plurality of flat glass fiber filaments 20 are bundled, and this fiber bundle is used in the method for producing flat glass fiber-containing pellets of the present invention described in detail below. Typical examples of the sizing agent component include film forming agents such as olefin resins (polyethylene, polypropylene, etc.), urethane resins, acrylic resins, epoxy resins, and oils, surfactants, silane coupling agents, antistatic agents, and the like. is there.

  The thermoplastic resin contained in the flat glass fiber-containing pellet includes polyamide resin, polybutylene terephthalate resin, polycarbonate resin, polyphenylene sulfide resin, liquid crystal polymer, polystyrene resin, polypropylene resin, polyethylene resin, polyethylene terephthalate resin, acrylic styrene resin, ABS. Examples thereof include a resin, and a polyamide resin is particularly preferable. As the polyamide resin, nylon (registered trademark) 6; nylon (registered trademark) 6, 6; nylon (registered trademark) 6, 10; nylon (registered trademark) 6, 12; The thermoplastic resin used for the flat glass fiber-containing pellet may be composed of a single component or a plurality of components.

  The pellet length of the flat glass fiber-containing pellet is preferably 2 to 50 mm as described above. The pellet length is more preferably 5 to 30 mm.

  A flat glass fiber-containing pellet is formed by passing a flat glass fiber bundle in which a plurality of long flat glass fiber filaments having a flat cross section are arranged and arranged together with a hot melted thermoplastic resin and a through hole formed in the die. It can be obtained by cutting through a fiber bundle to which a thermoplastic resin is adhered, which is obtained by pulling through a hole and pulling out.

  In this production method, a flat glass fiber bundle is used, and this flat glass fiber bundle is a known glass fiber strand that is bundled with a sizing agent while cooling a plurality of molten flat glass fiber filaments drawn from a flat glass fiber bushing. It can manufacture with the manufacturing method of. This glass fiber strand can be wound around a winding core and stored as a wound body. By using this wound body, a flat glass fiber-containing pellet can be manufactured by applying the continuous production apparatus shown in FIG. 7, for example. .

  FIG. 7 is a schematic configuration diagram of a continuous manufacturing apparatus 200 for continuously manufacturing flat glass-containing pellets by the method of the present invention. As shown in FIG. 7, the continuous manufacturing apparatus 200 includes a thermoplastic resin tank 34 containing a thermoplastic resin 10a melted by heating, and flat glass fiber bundles 21 (a plurality of flat glass fiber filaments 20 are converged). A die 30 formed with a through hole 31 through which the thermoplastic resin 10a that has been melted with heat is passed, a puller 40 that pulls out a long flat glass fiber bundle to which the thermoplastic resin is attached, and the thermoplastic resin is attached. And a cutting machine 50 that cuts the long flat glass fiber bundle into a desired length to obtain the flat glass fiber-containing pellet 100.

  A wound body 22 around which a flat glass fiber bundle 21 to be introduced into the die 30 is wound is disposed on the upstream side of the die 30. The puller 40 located on the downstream side of the die 30 is a so-called caterpillar puller in which a long flat glass fiber bundle to which a thermoplastic resin is attached is sandwiched from above and below by a rotating roller. The cutting machine 50 is a cutting machine that cuts a long flat glass fiber bundle to which a thermoplastic resin is adhered by rotating a blade with a driving force of a motor M to obtain a flat glass fiber-containing pellet 100.

  In order to manufacture the flat glass fiber-containing pellet 100 using the continuous manufacturing apparatus 200, first, the puller 40 is rotationally driven, and the flat glass fiber bundle 21 is unwound and pulled out from the wound body 22. Then, the drawn flat glass fiber bundle 21 is introduced into the through hole 31 of the die 30, and the thermoplastic resin 10 a that is thermally melted using a pump or the like is guided to the through hole 31. In the die 30, the hot-melt thermoplastic resin 10 a adheres to and around the flat glass fiber bundle 21, and is wound into a shape corresponding to the outlet side cross-sectional shape of the through-hole 31 by winding the puller 40. The long flat glass fiber bundle to which the plastic resin is attached is pulled out from the cross-sectional die 30. Thereafter, the thermoplastic resin is solidified in a state suitable for cutting, and is cut by a cutting machine 50 to obtain flat glass fiber-containing pellets 100.

  Although one wound body 22 is used in FIG. 7, the flat glass fiber bundle 21 may be introduced into a plurality of dies 30 by using a plurality of the wound bodies 22. Further, a cooling means for promoting the solidification of the hot-melted thermoplastic resin may be installed on the lower process side of the die 30. Further, a molding means for adjusting the cross-sectional shape of the long flat glass fiber bundle to which the thermoplastic resin is attached may be installed between the die 30 and the puller 40.

  The flat glass fiber-containing pellets thus obtained can be put into a feeder of a known injection molding machine, heated and melted according to the type of thermoplastic resin used, and injection molded into a desired shape. . In addition to flat glass fiber-containing pellets, the same or different types of thermoplastic resin pellets used for the pellets can be added to the feeder of the injection molding machine, and other additives commonly used for injection molding (antistatic agents) , Mold release agents, etc.) can also be added.

  The obtained flat glass fiber-containing thermoplastic resin molded product is manufactured using the flat glass fiber-containing pellet of the present invention, so that not only the tensile strength but also the impact strength is improved and the direction to the molded product is improved. The phenomenon that the sexuality occurs is also suppressed. Further, warpage is prevented and surface smoothness is improved. Furthermore, the above effect is exhibited regardless of the type of thermoplastic resin, and stable characteristics can be obtained even for polyamide resins that have been difficult in the past.

  EXAMPLES Hereinafter, although the suitable Example of this invention is described in detail, this invention is not limited to a following example.

Example 1
<Preparation of pellet>
A flat glass long fiber (long flat glass fiber filament) having an E glass composition with a short diameter of 8 μm and a long diameter of 31 μm (flat rate of 3.8, converted fiber diameter of 17 μm) is coated with a urethane-based sizing agent, and 4000 pieces are bundled. Thus, a flat glass fiber bundle was obtained. This flat glass fiber bundle was introduced into hot-melted nylon (registered trademark) 6,6 (Leona 1300S manufactured by Asahi Kasei Co., Ltd.), melted and impregnated, and passed through a die having a circular through hole. The pellet of Example 1 whose glass content rate is 40 mass% was produced. Here, the “converted fiber diameter” refers to the diameter of a round cross-section fiber having a cross-sectional area equivalent to that of a flat glass fiber.
<Production of injection molded products>
The pellets of Example 1 were injection-molded at a cylinder temperature of 280 ° C., a mold temperature of 80 ° C., and an injection pressure of 4 MPa to prepare Test A and Test B of Example 1. The test piece A is a test piece having a length of 100 mm, a width of 12 mm, and a thickness of 3 mm having gripping portions on both sides in the length direction, and the test piece B is an 80 mm square flat test piece having a thickness of 1 mm.

(Comparative Example 1)
<Preparation of pellet>
E glass composition flat glass long fibers having a short diameter of 7 μm and a long diameter of 27 μm (flat rate of 3.8, converted fiber diameter of 15 μm) are coated with a urethane-based sizing agent, and 1600 fibers are bundled to obtain a flat glass fiber bundle. It was. This flat glass fiber bundle was cut into a length of 3 mm to obtain flat glass fiber chopped strands. The obtained flat glass fiber chopped strand was melt-kneaded with nylon 6 and 6 as in Example 1 at a temperature of 280 ° C., extruded from a die having a circular through hole with a diameter of 5 mm, cut into a length of 4 mm, and containing glass. A pellet of Comparative Example 1 having a rate of 40% by mass was produced. In the pellet of Comparative Example 1, flat glass fiber filaments were not arranged in one direction. In addition, although it tried to produce a pellet using the flat glass fiber chopped strand of length 10mm, the chopped strand could not be thrown into a screw but could not be melt-kneaded.
<Production of injection molded products>
A test piece A and a test piece B of Comparative Example 1 were produced in the same manner as in Example 1 except that the pellets of Comparative Example 1 were used.

(Comparative Example 2)
A pellet, test piece A, and test piece B of Comparative Example 2 were prepared in the same manner as in Example 1 except that a glass fiber having a circular cross section with a diameter of 17 μm was used.

(Comparative Example 3)
A pellet, test piece A, and test piece B of Comparative Example 3 were prepared in the same manner as in Comparative Example 1 except that glass fibers having a circular cross section with a diameter of 11 μm were used.

  About the test piece A obtained in Example 1 and Comparative Examples 1-3, tensile strength was measured according to JISK7054 "Tensile strength test method of glass fiber reinforced plastics". Further, according to JIS K7061 “Charpy impact test method for glass fiber reinforced plastic”, the Charpy impact strength was measured with the thickness direction as the impact direction.

  In addition, the test piece A was heated at 625 ° C. for 1 hour to burn the thermoplastic resin, and the length of the remaining glass fiber was subjected to image analysis using a real-time image processing analyzer of Nireco LUZEX FS, and the remaining fiber length was analyzed. (The length of the glass fiber filament in the glass fiber-containing molded product) was determined.

  Furthermore, about the test piece B obtained in Example 1 and Comparative Examples 1-3, the height of the place which floated most on the flat surface was measured, and curvature was evaluated. In addition, with a roughness tester manufactured by Mitutoyo Corp. Surf Test 501, the difference between the height of the highest point and the lowest point in the reference length of 0.8 mm was obtained, and the average value was calculated. Smoothness was evaluated. The above evaluation results are summarized in Table 1 below.

  Here, the glass fiber filament of Example 1 has a smaller converted fiber diameter than the glass fiber filament of Comparative Example 1, and the glass fiber filament of Comparative Example 2 has a smaller diameter than the glass fiber filament of Comparative Example 3. If the converted fiber diameters of the flat glass fiber filaments of Example 1 and Comparative Example 1 are the same, or if the diameters of the circular cross-section glass fiber filaments of Comparative Example 2 and Comparative Example 3 are the same, Example It can be easily imagined that 1 is superior to Comparative Example 1 and Comparative Example 2 is superior to Comparative Example 3 in terms of tensile strength and impact strength.

It is a perspective view of the flat glass fiber containing pellet which concerns on 1st Embodiment. (A) is a front view of the flat glass fiber containing pellet which concerns on 1st Embodiment, (b) is the same side view, (c) is the same top view. (A) is a front view of the flat glass fiber containing pellet which concerns on 2nd Embodiment, (b) is the same side view, (c) is the same top view. It is a figure explaining the major axis and minor axis of a flat glass fiber filament. It is a figure which shows the cross section (saddle type cross section) of a flat glass fiber filament. It is sectional drawing of the state in which the flat glass fiber filament with a cross-sectional shape gathered. It is a schematic block diagram of the continuous manufacturing apparatus for continuously manufacturing a flat glass containing pellet.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... The pellet which consists of thermoplastic resins, 10a ... Hot melted thermoplastic resin, 20 ... Flat glass fiber filament, 21 ... Flat glass fiber bundle, 22 ... Winding body, 30 ... Dies, 31 ... Through-hole, 40 ... Puller DESCRIPTION OF SYMBOLS 50 ... Cutting machine 100 ... Flat glass fiber containing pellet which concerns on 1st Embodiment, 110 ... Flat glass fiber containing pellet which concerns on 2nd Embodiment, 200 ... Continuous manufacturing apparatus.

Claims (8)

In pellets made of thermoplastic resin,
A flat glass fiber-containing pellet in which a plurality of flat glass fiber filaments having a flat cross section are arranged in one direction so that both end faces of the filament reach the pellet surface.   The flat glass fiber-containing pellet according to claim 1, wherein the flat glass fiber filament has a fiber length of 2 to 50 mm, and the number of the flat glass fiber filaments arranged in the pellet made of the thermoplastic resin is 500 to 8000. .   The flat glass fiber-containing pellet according to claim 1 or 2, wherein the thermoplastic resin is a polyamide resin. A fiber bundle in which a plurality of long flat glass fiber filaments having a flat cross section are aligned and arranged,
Along with the hot-melt thermoplastic resin, pull through the through-hole of the die in which the through-hole is formed,
A method for producing flat glass fiber-containing pellets, which is obtained by cutting a fiber bundle to which a thermoplastic resin is attached, which is obtained by drawing.   The manufacturing method according to claim 4, wherein the thermoplastic resin is a polyamide resin.   The flat glass fiber containing pellet which can be obtained with the manufacturing method of Claim 4 or 5.   A method for producing a flat glass fiber-containing thermoplastic resin molding, which comprises injection-molding the flat glass fiber-containing pellet according to claim 1, 2, 3 or 6.   The flat glass fiber containing thermoplastic resin molding which can be obtained with the manufacturing method of Claim 7.

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