JP2023074133A - Method for manufacturing doubled yarn roving, doubled yarn roving, glass fiber-reinforced resin molded product - Google Patents

Abstract

To provide a method for manufacturing a doubled yarn roving that can effectively increase mechanical strength of a resin molded product.SOLUTION: A method for manufacturing a doubled yarn roving 10 includes the steps of: forming a glass strand by binding several glass filaments having a flat cross-sectional shape and a flatness ratio (major axis/minor axis) of 3.0-6.0; and obtaining a doubled yarn roving 10 by doubling several glass strands.SELECTED DRAWING: Figure 2

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a doubling roving, a doubling roving, and a glass fiber reinforced resin molding using the doubling roving.

BACKGROUND ART Conventionally, a glass fiber-reinforced resin molded article obtained by combining glass fiber and resin has been attracting attention as a metal substitute because it is lightweight and has excellent mechanical strength. In particular, a resin molded article using glass strands in which continuous glass long fibers are bundled is compared with a case using a composite in which glass chopped strands cut to a predetermined length are dispersed in a resin. In addition, since the remaining fiber length inside the resin molding becomes longer, an improvement in mechanical strength is expected.

For example, in Patent Document 1 below, fiber bundles in which 500 to 8,000 long flat glass fiber filaments with an oblateness of 3 to 8 are aligned and arranged are formed with a thermoplastic resin that is heat-melted, and through holes are formed. A method for producing flat glass fiber-containing pellets is disclosed in which the fiber bundle is pulled out through the through hole of the die, and the fiber bundle to which the thermoplastic resin is attached is cut. In Patent Document 1, an injection-molded article of flat glass fiber-containing pellets obtained by such a production method is an injection-molded article of pellets obtained by melt-kneading flat glass fiber chopped strands and a thermoplastic resin. In comparison, it is described that the residual fiber length is long and the impact strength is enhanced.

Japanese Patent No. 4876377

However, as in Patent Document 1, there is a problem that it is difficult to sufficiently increase the mechanical strength even in a glass fiber reinforced resin molded body using a strand formed by bundling glass filaments having a flat cross-sectional shape. .

An object of the present invention is to provide a method for manufacturing a doubling roving, a doubling roving, and a glass fiber reinforced resin molded product using the doubling roving, which can effectively increase the mechanical strength of the resin molded product. That's what it is.

In the method for producing a doubling roving according to the present invention, a glass strand is formed by bundling a plurality of glass filaments having a flat cross-sectional shape and a flatness ratio (major axis/minor axis) of 3.0 to 6.0. and a step of obtaining a doubling roving by doubling a plurality of the glass strands.

In the present invention, in the step of obtaining the doubling roving, it is preferable to doubling a plurality of the glass strands by unwinding using a winder, using an air splicer, or using a resin yarn.

In the present invention, it is preferable to doubling so that the count of the doubling roving is 800 tex or more and 5000 tex or less.

A doubling roving according to the present invention is a doubling roving obtained by doubling a plurality of glass strands, wherein the glass strands have a flattened cross-sectional shape and a flatness ratio (major axis/minor axis) of 3.0 to 6.0, when both ends of the doubling roving made of glass filaments and stretched in the horizontal direction are fixed to support members arranged horizontally at a distance of 2 m, the horizontal It is characterized in that the width of slack to the glass strand that hangs most downward in the direction is 30 mm or more and 100 mm or less.

The glass fiber reinforced resin molded article according to the present invention is a resin molded article containing a doubling roving constructed according to the present invention and a resin, and the content of the glass fiber contained in the resin molded article is 30 mass. % or more and 80 mass % or less.

In the present invention, it is preferable that the fiber length of the glass fiber contained in the resin molding is 500 μm or more and 3000 μm or less.

INDUSTRIAL APPLICABILITY According to the present invention, there are provided a method for manufacturing a doubling roving, a doubling roving, and a glass fiber reinforced resin molded product using the doubling roving, which can effectively increase the mechanical strength of a resin molded product. be able to.

FIG. 1 is a schematic diagram for explaining a method of doubling glass strands by unwinding using a winder. FIG. 2 is a schematic perspective view showing a doubling roving according to one embodiment of the present invention. FIG. 3 is a schematic diagram for explaining a method of measuring the slack width. FIG. 4 is a schematic diagram showing an example of a method for manufacturing a glass fiber reinforced resin molding according to one embodiment of the present invention.

Preferred embodiments are described below. However, the following embodiments are merely examples, and the present invention is not limited to the following embodiments. Also, in each drawing, members having substantially the same function may be referred to by the same reference numerals.

[Manufacturing method of doubling roving]
In the method for producing a doubling roving of the present invention, first, a plurality of glass filaments having a flat cross-sectional shape and a flatness ratio (major axis/minor axis) of 3.0 to 6.0 are bundled to form a glass strand. Form (strand forming step). Next, a plurality of the glass strands are combined (a process of combining the glass strands). Thereby, the doubling roving of the present invention can be obtained.

Each step will be described in detail below.

(Strand formation step)
First, a plurality of glass filaments are formed. Specifically, frit fed into a glass melting furnace is melted to form molten glass. After homogenizing the molten glass, the molten glass is pulled out through a heat-resistant nozzle attached to the bushing. After that, the drawn molten glass is cooled to obtain a plurality of glass filaments (monofilaments). As the bushing, for example, a platinum bushing can be used.

When forming a plurality of glass filaments, glass filaments having a flat cross-sectional shape and a flatness ratio of 3.0 to 6.0 are formed. Specifically, a glass filament having a flat cross-sectional shape and a flatness ratio of 3.0 to 6.0 is formed by withdrawing molten glass from a nozzle having a flat cross-sectional shape.

In this specification, the term “flat cross-sectional shape” refers to a flat shape having a non-circular cross-sectional shape, and a flat shape such as an oval shape or an elliptical shape if the cross-sectional shape is flat. It shall be used in the sense that it also includes

In this specification, the flatness ratio is defined as the length of the longest side passing through the center of gravity in the cross section of the glass filament, and the width of the side perpendicular to the long side passing through the center of gravity as the short diameter. It can be represented by a ratio (major axis/minor axis).

In the present invention, since the glass strand is formed of glass filaments having a flat cross-sectional shape and a flatness ratio of 3.0 to 6.0, the obtained doubling roving is used to produce a resin molding. When this is done, the mechanical strength of the resin molding can be enhanced.

When the flatness ratio of the glass filament is 3.0 or more, which is the lower limit value described above, the aspect ratio of the cross section of the glass filament increases, so that the mechanical strength of the resin molding can be increased. On the other hand, when the flatness ratio of the glass filament is 6.0 or less, which is the upper limit value described above, the glass fiber is less likely to break due to the shear stress applied when kneading with the resin in injection molding or the like. can increase

From the viewpoint of further increasing the mechanical strength of the resin molding, the flatness ratio (major axis/minor axis) of the glass filament is preferably 3.5 or more and preferably 5.0 or less.

When forming a plurality of glass filaments, it is preferable to form glass filaments having an equivalent circle diameter of 5 μm or more and 23 μm or less. When the circle-equivalent diameter of the glass filaments is equal to or greater than the above-described lower limit, the flattened cross-sectional shape can be more easily maintained when the resin molding is produced. Further, when the equivalent circle diameter of the glass filament is equal to or less than the upper limit value described above, the toughness of the glass filament itself can be further enhanced, and furthermore, fluffing can be further suppressed.

In this specification, the equivalent circle diameter corresponds to the diameter of a perfect circle obtained by obtaining the cross-sectional area of the glass filament.

Raw materials for glass filaments (glass raw materials) are not particularly limited, and examples thereof include E glass, S glass, D glass, and AR glass. Among these, E glass is inexpensive and can further increase the mechanical strength of the resin molding. In addition, S glass can further increase the mechanical strength of the resin molding.

The number of glass filaments (monofilaments) constituting the glass strand is not particularly limited, but is preferably 200 or more, more preferably 600 or more, and preferably 3000 or less, more preferably 1500 or less. When the number of glass filaments is within the range described above, the mechanical strength of the resin molding can be further enhanced.

Next, a sizing agent is applied to the surface of the obtained plurality of glass filaments by a sizing agent application mechanism. Hundreds to thousands of glass filaments are aligned and bundled while the sizing agent is evenly applied. A plurality of glass filaments can be aligned and focused by, for example, a focusing shoe. Thereby, a glass strand can be formed.

The sizing agent is, for example, one or more thermoplastic resins selected from the group consisting of polyolefin resins such as polypropylene resins, acrylic resins, nylon resins, polyvinyl acetates, and polyphenylene sulfide resins, or polyesters (unsaturated polyesters). It may contain one or more thermosetting resins selected from the group consisting of resins, epoxy resins, and polyurethane resins. Components such as a silane coupling agent such as aminosilane, a lubricant, a nonionic surfactant, or an antistatic agent may be added to the sizing agent. Moreover, the mass ratio of the sizing agent to the total amount of the solid matter of the glass filaments and the sizing agent can be, for example, 0.2% by mass or more and 2.0% by mass or less.

Next, the resulting glass strand is wound around a rotating collet to produce a wound body. Subsequently, the wound body is removed from the collet, the sizing agent is dried, and a coating is formed on the surface of the monofilaments constituting the glass strands to obtain a cake.

(Double yarn process)
Next, a doubling roving is obtained by doubling a plurality of glass strands obtained as described above. The method for doubling the glass strands is not particularly limited, but for example, the glass strands can be doubling by unwinding using a winder.

FIG. 1 is a schematic diagram for explaining a method of doubling glass strands by unwinding using a winder. As shown in FIG. 1, in the present embodiment, a plurality of glass strands 1a to 1e drawn out from five cakes 1A to 1E prepared by the above method are bundled and wound to form a doubling roving 10. A rotating body 11 can be obtained.

In addition, in the present invention, a plurality of glass strands may be spliced using an air splicer (thread splicing machine). Alternatively, a plurality of glass strands may be combined by binding with a resin thread.

As described above, in the production method of the present invention, a doubling roving is produced by doubling a plurality of glass strands. Since there is a difference in yarn length between the glass strands constituting the doubling roving thus obtained, the glass strands sag when the doubling roving is stretched in the horizontal direction. Therefore, the doubling roving obtained by the production method of the present invention is excellent in impregnating property with molten resin, and can form a resin molding excellent in mechanical strength.

[Mixed yarn roving]
FIG. 2 is a schematic perspective view showing a doubling roving according to one embodiment of the present invention. In FIG. 2 , a wound body 11 is formed by winding a doubling roving 10 . The wound body 11 has a substantially cylindrical structure in which the doubling rovings 10 are wound in layers in the radial direction. The inner peripheral side of the wound body 11 is hollow. However, a core such as a bobbin may be arranged in the center of the wound body 11 .

The doubling roving 10 is formed by doubling a plurality of glass strands. The number of the glass strands is preferably 2 or more, more preferably 3 or more, preferably 12 or less, more preferably 8 or less, still more preferably 6 or less. The glass strand is composed of glass filaments having a flat cross-sectional shape and a flatness ratio (major axis/minor axis) of 3.0 to 6.0. Such a doubling roving 10 can be manufactured, for example, by the method for manufacturing a doubling roving described above.

In this embodiment, when the measurement shown in FIG. 3 is performed, the slack width per 2 m of the glass strand is 30 mm or more and 100 mm or less. In addition, the test shown in FIG. 3 can be performed as follows.

First, the doubling roving 10 pulled out from the wound body 11 is cut to a length of 2 m or more (approximately 2 m to 2.2 m). Next, the doubling roving 10 is stretched in the horizontal direction x with both ends aligned. Both ends of the doubling roving 10 stretched in the horizontal direction x are fixed to supporting members 13 and 14 which are spaced apart by 2 m in the horizontal direction x. At this time, both ends of the doubling roving 10 can be fixed to the support members 13 and 14 using an adhesive or the like. Next, the slack width L up to the glass strand 12a which hangs down most downward in the horizontal direction x is measured. Note that the slack width L is the distance between the glass strand 12b extending in the horizontal direction x and the lowest portion of the glass strand 12a hanging most downward in the vertical direction z orthogonal to the horizontal direction x.

In the doubling roving 10 of the present embodiment, the slack width L per 2 m of the glass strand is 30 mm or more, so that it is excellent in the impregnating property with the molten resin. In addition, since the slack width L per 2 m of the glass strand is 100 mm or less, disconnection is unlikely to occur when compounding with the resin, and the fiber length of the glass fiber in the resulting resin molded product can be increased. can. Therefore, according to the doubling roving 10 of the present embodiment, the mechanical strength of the resin molding can be effectively increased.

In addition, from the viewpoint of further increasing the mechanical strength of the resin molding, the slack width L per 2 m of the glass strand is preferably 40 mm or more, more preferably 55 mm or more, preferably 90 mm or less, and more preferably 80 mm or less. .

In addition, the slack width L can be adjusted when the glass strands are doubling by unwinding using a winder, air splicer, resin yarn, or the like in the manufacturing method of the doubling roving 10 described above. For example, the slack width L can be adjusted by changing the distance from each of the cakes 1A to 1E shown in FIG.

The count of the doubling roving 10 is preferably 800 tex or more, more preferably 1000 tex or more, still more preferably 1200 tex or more, preferably 5000 tex or less, more preferably 4800 tex or less, still more preferably 3600 tex or less, and particularly preferably 2400 tex or less. be. When the yarn count of the doubling roving 10 is within the above range, the mechanical strength of the resin molding can be more effectively enhanced.

[Glass fiber reinforced resin molding]
The glass fiber reinforced resin molded article of the present invention includes the doubling roving of the present invention described above and a resin.

The resin is not particularly limited, and a thermoplastic resin or a thermosetting resin can be used. Examples of thermoplastic resins include polypropylene resins, modified polypropylene resins, polyamide resins, polyphenylene sulfide resins, and polyurethane resins. Modified polypropylene resins include acid-modified polypropylene resins such as maleic acid-modified polypropylene resins. Thermosetting resins include, for example, polyvinyl acetate, polyester, and epoxy resins. Among them, the resin is preferably a polyamide resin or an acid-modified polypropylene resin. In addition, these resin may be used individually by 1 type, and may use multiple types together.

An example of a method for manufacturing a glass fiber reinforced resin molding according to an embodiment of the present invention will be described below with reference to FIG.

First, as shown in FIG. 4 , the doubling roving 10 is pulled out from the wound body 11 and transported to the resin impregnation tank 21 . In the resin impregnation bath 21, molten thermoplastic resin is supplied from a resin layer (not shown). Therefore, the doubling roving 10 can be impregnated with the resin by conveying it to the resin impregnation tank 21 .

Next, the doubling roving 10 is pulled out from the pull-out hole 22 of the resin impregnation bath 21 and conveyed toward the cutting machine 23 . Then, the glass fiber-containing pellets 30 are obtained by cutting into predetermined lengths by the cutting machine 23 .

The obtained glass fiber-containing pellets 30 are molded into a glass fiber reinforced resin molding by injection molding or the like.

Since the glass fiber reinforced resin molded article of the present invention includes the doubling roving 10 of the present invention described above, it has excellent mechanical strength. This can be explained as follows.

In order to increase the mechanical strength of a glass fiber reinforced resin molded article, it is necessary to increase the length of residual fibers in the resin molded article and improve the adhesion between the glass fibers and the resin.

However, if the kneading conditions are moderated during injection molding, the residual fiber length becomes long, but the adhesion between the resin and the glass fibers is lowered, and the mechanical strength of the resulting resin molded product cannot be sufficiently increased. On the other hand, if the kneading conditions are severe in injection molding, the adhesiveness between the resin and the glass fibers is improved, but the length of the residual fibers in the resin molding is shortened, and the mechanical strength of the obtained resin molding is sufficiently increased. I can't.

On the other hand, in the doubling roving of the present invention, since the slack width per 2 m of the glass strand is 30 mm or more and 100 mm or less, the impregnation of the glass fiber into the molten resin is excellent, and the kneading conditions are not strict. Even so, the adhesion between the resin and the glass fiber can be sufficiently enhanced. Thus, in the doubling roving of the present invention, the residual fiber length in the resin molded product can be increased and the adhesion between the glass fibers and the resin can be enhanced, so that the mechanical strength of the resin molded product can be effectively improved. can be increased to

In the present invention, the glass fiber content in the resin molded product is preferably 30% by mass or more, more preferably 40% by mass or more, preferably 80% by mass or less, and more preferably 60% by mass or less. When the glass fiber content is within the range described above, the mechanical strength of the resin molding can be further enhanced.

In the present invention, the fiber length (remaining fiber length) of the glass fibers in the resin molded product is preferably 500 µm or more, more preferably 1500 µm or more, preferably 3000 µm or less, and more preferably 2800 µm or less. When the fiber length of the glass fiber is equal to or greater than the above lower limit, the mechanical strength of the resin molding can be further enhanced. In addition, when the fiber length of the glass fiber is equal to or less than the above-described upper limit, the impregnability into the molten resin can be further improved, and the mechanical strength of the resin molding can be further improved.

Hereinafter, the present invention will be described in more detail based on specific examples. The present invention is by no means limited to the following examples, and can be modified as appropriate without changing the gist of the invention.

(Example 1)
First, a sizing agent was applied to 800 glass filaments pulled out from a bushing, and the glass strands bundled were wound around a collet, and the sizing agent was dried to prepare a cake (wound body). The glass filament uses glass with an E-glass composition, and the shape of the nozzle and the temperature of the molten glass are adjusted so that the cross-sectional shape is flat, the equivalent circle diameter is 16.1 μm, and the flatness ratio (major axis/minor axis ) was 3.1. In the same manner, five rolls of cake were produced in total, and these rolls were unwound and combined using a winder while applying a predetermined tension to obtain 4,000 glass filaments to obtain a combined roving. . The resulting doubling roving and polypropylene were compounded using an LFT (long fiber reinforced resin) pelletizer to obtain glass fiber reinforced resin pellets. The obtained pellets were injection-molded to prepare test pieces (resin moldings) according to ISO. The glass fiber content is as shown in Table 1 below.

(Examples 2-5)
Glass fiber was prepared in the same manner as in Example 1, except that the shape of the nozzle was changed, and the equivalent circle diameter, flatness ratio (major axis/minor axis), and number of strands were changed to the values shown in Table 1 below. A reinforced resin pellet and a test piece (resin molding) were produced.

(Comparative Examples 1 to 3)
First, a sizing agent was applied to 4000 glass filaments pulled out from a bushing, and the bundled strand was wound around a collet, and the sizing agent was dried to prepare a cake (wound body). The glass filament was made of glass having an E-glass composition, and was produced so that the equivalent circle diameter and the flatness ratio were the values shown in Table 1 below. The strand pulled out from the resulting cake and polypropylene were compounded using an LFT pelletizer to obtain glass fiber reinforced resin pellets. The obtained pellets were injection-molded to prepare test pieces (resin moldings) according to ISO. That is, in Comparative Examples 1 to 3, the strands are not doubled.

(Comparative Examples 4 and 5)
Glass fiber was prepared in the same manner as in Example 1, except that the shape of the nozzle was changed and the glass filament was produced so that the flatness ratio (major axis/minor axis) and equivalent circle diameter were the values shown in Table 1 below. A reinforced resin pellet and a test piece (resin molding) were produced.

[evaluation]
(flatness ratio, circle equivalent diameter)
First, the measurement of the flatness ratio will be described. In order to observe the cross section of the glass filament, a plurality of glass filaments were vertically embedded in a room-temperature curing resin Technovit (manufactured by Kulzer) and polished after curing the resin. Next, the cross-sectional shape of the glass filament was observed with an electron microscope, and the major and minor diameters of the observed glass filament were measured to calculate the oblateness ratio and the arithmetic mean of the oblateness ratio. The number of glass filaments was 100.

The equivalent circle diameter was determined from the cross-sectional area obtained by image analysis of the cross-sectional area of the cross-sectional shape of 100 glass filaments.

(Remaining fiber length of glass fiber)
First, the resin molded body was heated in an incinerator at 650° C. to decompose organic substances in the resin molded body. Next, the glass fibers after incineration were transferred to a glass petri dish, and acetone was used to disperse the glass fibers in the glass petri dish. Next, in 1000 or more glass fibers in the glass petri dish, the fiber length was measured using an electron microscope (product number "RX-2000HiROX" manufactured by Hirox Co., Ltd.), and the average value of the 100 fibers was taken as the residual fiber length. .

(Measurement of slack width)
First, the doubling roving was cut to a length of 2 m (approximately 2 m to 2.2 m). Next, both ends of the doubling roving were aligned and stretched in the horizontal direction. Both ends of the horizontally stretched doubling roving were fixed to supporting members horizontally spaced apart by 2 m. At this time, both ends of the doubling roving were fixed to the support member using an adhesive. Next, the width of sag up to the glass strand that hangs down most in the horizontal direction was measured. The slack width was calculated from the distance between the horizontally extending glass strand and the lowest part of the glass strand hanging most downward in the vertical direction orthogonal to the horizontal direction.

(tensile strength)
A test piece conforming to ISO527-1 is prepared, and a precision universal testing machine (manufactured by Shimadzu Corporation, Autograph AG-X plus 50kN) is used to perform a test under conditions conforming to ISO527-1, and the tensile strength is measured. bottom.

(bending strength)
A test piece conforming to ISO178 was prepared and tested under conditions conforming to ISO178 using a precision universal testing machine (manufactured by Shimadzu Corporation, Autograph AG-X plus 10 kN) to measure bending strength.

(Charpy impact strength)
A test piece conforming to ISO179 was prepared, and an impact tester (UF impact tester manufactured by Ueshima Seisakusho Co., Ltd.) was used to perform a test under conditions conforming to ISO179 to measure the Charpy impact strength.

The results are shown in Table 1 below.

As shown in Table 1, the glass fibers (glass filaments) contained in the glass fiber-reinforced resin molded articles of Examples 1 to 5 had a flat cross-sectional shape and a flatness ratio (major axis/minor axis) of 3. above and below 6. The glass fiber reinforced resin moldings of Examples 1 to 4 were obtained by using five strands of 800 filaments of glass fiber, unwinding them with a winder, and combining them. The glass fiber reinforced resin molding of Example 5 was obtained by unwinding 11 strands of the 800 filaments of glass fiber using a winder and combining them. Furthermore, the glass fiber reinforced resin moldings of Examples 1 to 5 have a slack width of 30 mm or more and 100 mm or less per 2 m of yarn length. The glass fiber reinforced resin moldings of Examples 1 to 5 all have a tensile strength of 175 MPa or more, a bending strength of 255 MPa or more, and a Charpy impact strength of 48 kJ/m ² or more, and have high mechanical strength. was On the other hand, the resin moldings of Comparative Examples 1 to 5 did not satisfy any of the above conditions, and sufficient mechanical strength was not obtained.

DESCRIPTION OF SYMBOLS 1A, 1B, 1C, 1D, 1E... Cake 1a, 1b, 1c, 1d, 1e, 12a, 12b... Glass strand 10... Duplex roving 11... Winding body 13, 14... Support member 21... Resin impregnation tank 22... Drawing hole 23... Cutting machine 30... Glass fiber-containing pellet

Claims (6)

A step of forming a glass strand by bundling a plurality of glass filaments having a flat cross-sectional shape and a flatness ratio (major axis/minor axis) of 3.0 to 6.0;
a step of obtaining a doubling roving by doubling a plurality of the glass strands;
A method for manufacturing a doubling roving, comprising: 2. The method of manufacturing a doubling roving according to claim 1, wherein in the step of obtaining the doubling roving, the plurality of glass strands are conjugated by unwinding using a winder, by an air splicer, or by resin yarn. 3. The method of manufacturing a doubling roving according to claim 1 or 2, wherein the doubling is performed so that the count of the doubling roving is 800 tex or more and 5000 tex or less. A doubling roving obtained by doubling a plurality of glass strands,
The glass strand is composed of glass filaments having a flattened cross-sectional shape and a flatness ratio (major axis/minor axis) of 3.0 to 6.0,
When both ends of the doubling roving stretched in the horizontal direction are fixed to support members arranged horizontally at a distance of 2 m, the width of slack to the glass strand hanging most downward in the horizontal direction is 30 mm. A doubling roving having a length of 100 mm or more. A resin molding comprising the doubling roving according to claim 4 and a resin,
A glass fiber-reinforced resin molded article, wherein the content of glass fibers contained in the resin molded article is 30% by mass or more and 80% by mass or less. 6. The glass fiber-reinforced resin molding according to claim 5, wherein the fiber length of the glass fibers contained in the resin molding is 500 μm or more and 3000 μm or less.

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