JP5818179B2 - Modified cross section glass fiber - Google Patents

Description

  The present invention relates to an improved technique for a modified cross-section glass fiber in which a cross section perpendicular to the spinning direction forms a flat shape.

  As is well known, glass fiber is widely used as a reinforcing material added to various resin materials. Conventionally, this type of glass fiber has been used in many cases in which the shape of the cross-section is a substantially true circle. When added to a resin material, a treatment agent or the like is attached to the surface of the glass fiber. Thus, an adhesive force is applied to the interface between the glass fiber and the resin.

  However, in recent years, composite materials including resin materials and glass fibers have been used in a wider range of fields, and further improvements in strength of composite materials are required. Therefore, in order to meet the demand, instead of glass fibers having a substantially true circular cross section, a glass fiber having an irregular cross section such as an oval or elliptical cross section has been proposed (for example, Patent Document 1, 2). Such a modified cross-section glass fiber has an increased surface area compared to a glass fiber having a substantially round cross section, and therefore when the glass fiber is added to a resin material, the contact area with the resin material increases. Since the adhesive force is improved, the strength of the composite material as a whole can be improved.

JP 61-174141 A JP 2000-103635 A

  However, even in the modified cross-section glass fiber disclosed in Patent Documents 1 and 2, at the interface between the glass fiber and the resin material, only the local planes are chemically bonded by adhesion, When an excessive load acts on the interface in the shear direction, there may arise a problem that the adhesion between the glass fiber and the resin material peels relatively easily. Therefore, it is still insufficient for improving the strength of the composite material.

  In view of the above circumstances, it is an object of the present invention to provide a glass fiber having a modified cross section that can reliably improve the strength of a composite material when the composite material is formed by mixing with a resin material. .

  The glass fiber according to the present invention created in order to solve the above problems is a modified cross-section glass fiber having a flat cross section perpendicular to the spinning direction, and is formed of E glass. And having a pair of main surfaces extending in the direction of the major axis passing through the center of gravity and facing in the direction of the minor axis passing through the center of gravity and orthogonal to the major axis, and having a protrusion only on the one main surface. The protrusions are formed at both ends in the major axis direction, and the non-protrusion part formed between the protrusions of the one main surface is substantially linear, and The non-projection part formation region is characterized by being wider in the major axis direction than the projection part formation region.

  According to such a configuration, when a glass fiber is mixed with a resin material to form a composite material, the bonding force between the glass fiber and the resin material is the bonding force due to adhesion at the interface between the glass fiber and the resin material. In addition to this, it is also strengthened by the engagement between the glass fiber protrusions and the resin material and the coupling force due to the engagement between the glass fiber protrusions. Therefore, even if a load is applied to the interface between the glass fiber and the resin material in the shear direction, the glass fiber and the resin material are bonded by the engagement between the glass fiber protrusion and the resin material and the engagement between the glass fiber protrusions. It is possible to reliably prevent the situation where peeling easily occurs between the two.

  Said structure WHEREIN: It is preferable that the flatness ratio of the said cross section exists in the range of 1.5-10.0.

  That is, when the cross-sectional flatness ratio is less than 1.5, it is not preferable because an anisotropy improving effect with a sufficient shrinkage rate may not be realized when used in a composite material. Moreover, when the flatness ratio of a cross section exceeds 10.0, manufacturing conditions etc. will become severe, and since the management of the external shape of the irregular cross-section glass fiber shape | molded may become difficult, it is unpreferable.

  Therefore, it is preferable that the cross-sectional flatness ratio is in the above-described range, and if it is within this range, when the composite material is formed by mixing with the resin material, the effect of improving the anisotropy with a sufficient shrinkage ratio is high. Shape stability can be realized at the same time. And from the viewpoint of enjoying such effects, the cross-sectional flatness ratio is more preferably in the range of 2.1 or more and 9.0 or less, and the range of 2.3 or more and 8.0 or less. Is more preferably in the range of 2.5 to 7.0, and most preferably in the range of 2.7 to 6.0.

  Said structure WHEREIN: It is preferable that the perfect circle equivalent diameter of the said cross section exists in the range of 5 micrometers or more and 30 micrometers or less. The true circle equivalent diameter here means the diameter of a perfect circle having an area equal to the area of the cross section of the glass fiber.

  In this way, glass fibers with fiber diameters corresponding to various composite materials used for various purposes can be applied, so the product dimensions of various composite materials must be adjusted more precisely than before. Is possible.

  In the above configuration, the case where the center of the radius of curvature at each point of the contour of the cross section is inside the cross section is negative, the case where it is outside the cross section is positive, and the position of the contour of the cross section is positive. In the function representing the radius of curvature with the contour length up to each point as a variable starting from an arbitrary point, the projection point where the first derivative is zero and the second derivative is negative is the contour of the cross section You may have on.

  According to the modified cross-section glass fiber according to the present invention as described above, when a composite material is formed by mixing with a resin material, the strength of the composite material can be reliably improved.

It is the cross-sectional view which showed notionally the irregular cross-section glass fiber which concerns on Example 1 of this invention. It is explanatory drawing regarding the manufacturing equipment of the irregular cross-section glass fiber which concerns on Example 1, (A) is a partial whole figure, (B) is an expanded longitudinal cross-sectional view of the X section of (A), (C) is (B). YY sectional views are shown respectively. 2 is a photograph of a cross-sectional shape of a modified cross-section glass fiber according to Example 1. It is a photograph of the cross-sectional shape of the irregular cross-section glass fiber which concerns on Example 3 of this invention. It is the cross-sectional view which showed notionally the modified example of the irregular cross-section glass fiber based on the Example of this invention.

  Embodiments according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view of a modified cross-section glass fiber according to Example 1 of the present invention. This glass fiber 10 is formed by drawing and molding from a nozzle after performing a mixing and homogenizing operation such as stirring so that the molten glass made of E glass is in a homogeneous state. For example, the glass fiber 10 is a composite mixed with a resin material. Used as a structural material for electronic parts in the form of materials.

  As shown in FIG. 1, this glass fiber 10 has a cross section perpendicular to the spinning direction, a long axis (longest dimension axis) L passing through the center of gravity P, and passing through the center of gravity P and perpendicular to the long axis L. It has a flat shape having a short axis (shortest dimension axis) S, and its external features are as follows.

  That is, the external feature of the glass fiber 10 is that one or more protrusions 12 are formed in the outline of the cross section. More specifically, the glass fiber 10 has a pair of main surfaces 11a and 11b extending along the major axis L direction and opposed in the minor axis S direction. Due to the difference in temperature distribution of the molten glass G at the time, both end portions in the major axis L direction are formed to bulge to one side 11b of the pair of main surfaces 11a and 11b. The non-projection portions 13 formed between the projection portions 12 are substantially linear, and the formation region of the non-projection portions 13 is wider in the major axis L direction than the formation region of the projection portions 12. In addition, the protrusion part 12 is formed so that it may continue along the full length of the glass fiber 10, ie, a spinning direction. When the glass fiber 10 is mixed with the resin material by the protrusion 12, the bonding force between the glass fiber 10 and the resin material is not only the bonding force due to adhesion at the interface between the glass fiber 10 and the resin material. Further, it can be strengthened by the engagement between the projection 12 of the glass fiber 10 and the resin material and the coupling force due to the engagement between the projections 12 of the glass fiber 10. Therefore, the bonding force between the glass fiber 10 and the resin material is increased, and the mechanical strength of the composite material can be reliably improved. As a result, even if a load is applied to the interface between the glass fiber 10 and the resin material in the shearing direction, due to the coupling force due to the engagement between the projection 12 of the glass fiber 10 and the resin material and the engagement between the projections 12 of the glass fiber 10 In addition, it is possible to reliably prevent a situation in which peeling easily occurs between the glass fiber 10 and the resin material.

  Each protrusion 12 has a maximum height when a line segment connecting the start point (rising point) and the end point (falling point) of the protrusion 12 on the contour line of the cross section of the glass fiber 10 is defined as the bottom. It is preferable that it is 1/5 or less of the major axis direction dimension A passing through the center of gravity P of the cross section. Furthermore, when the projection 12 has a line segment connecting the start point and the end point as the base, the length of the transverse line of the projection 12 that is parallel to the base and half of the maximum height is long. The axial dimension A is preferably 1/5 or less. Further, the protrusion 12 is formed by having a local contour portion having the center of the radius of curvature outside the contour of the cross section.

  Another feature of the outer shape of the glass fiber 10 is that it has asymmetry with respect to the long axis L passing through the center of gravity P of the cross section. Specifically, this asymmetry is mainly caused by the fact that the radius of curvature at both ends in the major axis direction of the glass fiber 10 shows different values (curvature radii R1 and R2 in the figure) with the major axis L as a boundary. Has arisen as. When the asymmetry is given to the long axis L in this way, the center of gravity P of the cross section is unevenly distributed in the short axis direction due to the asymmetry. Therefore, when the glass fiber 10 is filled in the resin material, the flow direction of the glass fiber 10 is likely to be irregular, and the orientation degree of the glass fiber 10 after being filled in the resin material can be relaxed. Therefore, the strength anisotropy of the molded composite material can be relaxed, and a composite material having more isotropic strength can be configured.

  Next, the manufacturing procedure of the glass fiber 10 comprised as mentioned above is demonstrated based on FIG. 2 (A)-(C).

  As shown in FIG. 2, the glass fiber 10 has a plurality of heat resistances (for example, platinum alloys) attached so as to hang from the bottom of a heat resistant (for example, platinum alloy) bushing 20 in which the molten glass G is stored. Manufactured) by cooling the molten glass G while spinning downward. The manufactured glass fiber 10 is wound up on a paper tube mounted on a winding device 30 disposed below. At this time, a fixed point observation of a specific position of the nozzle shape and the shape of the glass fiber 10 to be molded are managed by a sensor or the like, and the nozzle temperature and the spinning speed can be finely adjusted by reflecting the result. It is preferable to do.

  In the above-described manufacturing procedure, the nozzle hole 22 of the nozzle 21 to be used has a flat shape (having a long axis (longest dimension axis) T passing through the center of gravity P1 of the cross section as shown in FIG. It is composed of a single hole having an oval shape. Further, as shown in FIG. 2 (B), the nozzle 21 has a leading end portion in a spinning direction (drawing direction) from a peripheral portion of the nozzle hole 22 having a half or less circumference with the major axis T of the nozzle hole 22 as a boundary. A projecting portion 21a projecting along is formed. Therefore, the region excluding the protruding portion 21a at the tip of the nozzle 21 is a cutout portion 21b. In this embodiment, a protruding portion 21 a is formed on the peripheral edge corresponding to the half circumference of the nozzle hole 22, and the front end side of the peripheral edge corresponding to the remaining half circumference of the nozzle hole 22 is a notch 21 b.

  As shown in FIG. 2 (B), the shape of the nozzle 21 is based on a plane U including the major axis T of the nozzle hole 22 and parallel to the spinning direction of the molten glass G. On the other hand, it has asymmetry. Further, as shown in FIG. 2C, the nozzle 21 has a shape in which the planar shape of the contour has mirror symmetry with respect to the long axis T passing through the center of gravity P1.

  Further, the flatness ratio (major axis direction dimension / minor axis direction dimension) of the lower end opening of the nozzle hole 22 of the nozzle 21 serving as the outlet end of the molten glass G is in the range of 1.5 or more and 10.0 or less. It is preferable. If it does in this way, there exists an advantage that the cooling efficiency and moldability of the molten glass G will improve, and it will become easy to carry out precision shaping | molding of the flat glass fiber 10. FIG.

  When the molten glass G is spun from the nozzle 21 configured as described above, the surface on one side of the molten glass G facing the protruding portion 21a of the nozzle 21 flows down while being guided along the protruding portion 21a. The other surface of the molten glass G facing the notch 21b of the nozzle 21 is rapidly cooled through the notch 21b. Therefore, in the molten glass G, a difference in temperature distribution occurs between the side facing the protrusion 21a and the side facing the notch 21b. Therefore, due to the difference in temperature distribution, the surface of the molten glass G facing the notch 21b is first rounded due to surface tension, and in the process, both end sides in the major axis direction of the molten glass G It swells around the surface of the molten glass G that has flowed out from the protruding portion 21a side. Thereby, while the projection part 12 is formed in the both ends of the glass fiber 10 which cooled and solidified the said molten glass G, the non-projection part 13 is formed between the projection parts 12. FIG.

  In addition, since the protrusion part 21a of the nozzle 21 also has an effect which regulates a deformation | transformation of the molten glass G, the above wraparound of the molten glass G mainly guides the molten glass G directly under the protrusion part 21a, ie, the protrusion part 21a. Occurs when is released. Further, due to the effect of restricting deformation by the protruding portion 21a, the main surface 11b of the glass fiber 10 facing the protruding portion 21a rather than the main surface 11a of the glass fiber 10 facing the notched portion 21b side. Is less rounded as a whole and has a shape close to a straight line.

  And as a specific example of conditions for forming such a projection part 12, a spinning speed shall be 600 m / min and bushing temperature shall be 1100 degreeC. That is, in the glass fiber 10 manufactured under this spinning condition, the radius of curvature R1 and the radius of curvature R2 are different from each other, and the protrusions 12 that bulge about 1 μm toward the main surface 11b at both ends in the major axis L direction are formed. It has been confirmed that it appears. A cross-sectional photograph of the glass fiber 10 actually obtained under the above spinning conditions is shown in FIG. In the figure, the portion displayed in white indicates the glass fiber 10. The image shown in the figure is a photograph of the polished surface taken under a stereomicroscope after mirror-polishing the resin material in which the glass fiber 10 is embedded.

  In the example shown in FIG. 3, the deformed cross-section glass fiber 10 has a long-axis dimension A passing through the center of gravity P of the cross section of 43.5 μm, and is in contact with the contour excluding the protrusion 12 on the cross section parallel to this. The distance B between the parallel lines of the book was 10.2 μm. Therefore, the flatness ratio obtained by dividing the long-axis dimension A passing through the center of gravity P by the distance B between two parallel lines parallel to this and in contact with the contour of the cross section is 4.3, and is 1.5 or more and 10.0 or less Satisfies the range. Moreover, the circle equivalent diameter of this glass fiber 10 was 23.3 micrometers, and it satisfied the range of 5 micrometers or more and 30 micrometers or less. In addition, the cross section of this glass fiber 10 became asymmetric with respect to the long axis L, and also had non-target properties with respect to the short axis S.

  Moreover, although not shown in figure, the glass fiber 10 from which external dimensions etc. differ can be obtained by employ | adopting other conditions.

  The manufacturing conditions of the glass fiber 10 according to Example 2 were different from the manufacturing conditions of the glass fiber 10 according to Example 1 only in the spinning speed. That is, the bushing temperature was kept at 1100 ° C. and the spinning speed was 400 m / min. The glass fiber 10 manufactured under the spinning conditions is omitted from the cross-sectional photograph of the actually manufactured fiber, but the long-axis dimension A passing through the center of gravity P of the cross-section is 53.4 μm, which is parallel to this. The distance B between two parallel lines in contact with the contour excluding the protrusion 12 on the cross section was 13.5 μm. Therefore, the flatness ratio (A / B) in the cross section of the glass fiber 10 is 4.0, which satisfies the range of 1.5 or more and 10.0 or less. Further, the equivalent circle diameter of the glass fiber 10 was 28.9 μm, and the equivalent circle diameter satisfied a range of 5 μm to 30 μm. In addition, the cross section of the glass fiber 10 has asymmetry with respect to the long axis L and has symmetry with respect to the short axis S.

  Further, as the glass fiber 10 according to the third embodiment having a small outer dimension and a large flatness, there is the following one. That is, the glass fiber 10 which makes the cross-sectional photograph shown in FIG. 4 can be manufactured under the spinning conditions in which the spinning speed is 1500 m / min and the bushing temperature is 1100 ° C. This glass fiber 10 has a long-axis dimension A passing through the center of gravity P of the transverse section of 34.3 μm, and a distance B between two parallel lines parallel to this and contacting the contour excluding the protrusion 12 on the transverse section. Was 6.0 μm. Therefore, the flatness ratio (A / B) in the cross section of the glass fiber 10 is 5.7, which satisfies the range of 1.5 or more and 10.0 or less. Moreover, the circle equivalent diameter of this glass fiber 10 was 15 micrometers, and it satisfy | filled the range of 5 micrometers or more and 30 micrometers or less. Since the glass fiber 10 has a small equivalent circle diameter and high flatness, the effect of improving the anisotropy of the shrinkage rate is further increased.

  According to the modified cross-section glass fiber 10 according to the embodiment as described above, since one or more protrusions 12 are formed in the outline of the cross-section of the glass fiber 10, the glass fiber 10 is filled into a resin material and combined. In this case, the bonding strength between the glass fibers 10 or between the glass fibers 10 and the resin material is increased by the engagement of the protrusions 12, and the reinforcing effect can be improved.

  Moreover, since this projection part 12 is formed by the thermal deformation by the difference in temperature distribution of the molten glass G at the time of shaping | molding of the glass fiber 10, in the case of forming the projection part 12 directly by the shape of the nozzle hole 22 Thus, the situation where the shape of the nozzle hole 22 is complicated can be prevented. Therefore, since the shape of the nozzle hole 22 of the nozzle 21 can be a simple flat shape such as an oval as described above, the spinning route of the molten glass G can be simplified. Therefore, since the spinning state of the molten glass G can be stabilized, it is possible to appropriately form the protrusions 12 on the outline of the cross section of the glass fiber 10 while maintaining high molding accuracy.

  In addition, this invention is not limited to the said embodiment, It can implement in a various form.

  For example, a predetermined amount of various types of sizing agents may be applied to the fiber surface of the modified cross-section glass fiber 10 by various methods depending on the application.

  The irregular cross-section glass fiber 10 may be subjected to a predetermined twist as necessary, or may not be twisted at all.

  The modified cross-section glass fiber 10 may be expanded not only for FRP but also for applications where other glass fibers are used, such as concrete reinforcement applications, as necessary. In addition to this, it is used as an optical member that is molded into various display substrates etc. in combination with a transparent resin material using a glass composition having a desired transmittance and refractive index in consideration of optical performance, It can be used for various purposes such as heat-resistant shielding materials and laminated materials, and can also be applied to lightweight materials such as hollow glass fibers.

  The shape of the protrusion 12 of the modified cross-section glass fiber 10 may be, for example, an acute-angled shape or a gentle parabolic shape. Further, the protrusion 12 may be formed of a multi-stage convex portion including a convex portion having a relatively large cross section and a convex portion having a relatively small cross section provided at the tip thereof.

  Further, in the modified cross-section glass fiber 10 according to the above-described embodiment, it is preferable that one or more projecting contour portions (hereinafter referred to as projecting contour portions) including the projecting portions 12 and the like are formed on the contour of the cross section. . Here, with respect to the curvature radius of each point on the contour of the cross section of the glass fiber 10 perpendicular to the spinning direction, the protruding contour portion means that the position of the center of the curvature radius at each point on the contour is on the contour. Negative when the point is at the inner side of the cross section starting from each point, while positive when the center of the radius of curvature is at the point not starting from the inner side of the cross section starting from each point on the contour In the function representing the radius of curvature with the contour length to each point as a variable starting from an arbitrary point of, the point on the contour where the primary differential coefficient turns from positive to negative in the region where the radius of curvature is negative, A glass fiber having a point on the contour with a positive radius of curvature within a perfect circle that is a quarter of the diameter of a perfect circle having a diameter equal to that of the cross section centered on the point on the contour. Means the part of the cross section. And in the function representing the radius of curvature at each point on the contour with the contour length from an arbitrary point on the contour as a variable, the point on the contour where the differential coefficient turns from positive to negative in the negative curvature radius region The cross-sectional profile of the glass fiber 10 perpendicular to the spinning direction has a shape protruding outward, but the cross-sectional profile of the glass fiber perpendicular to the spinning direction is conversely different in that the differential coefficient turns from negative to positive. It has a gentle shape. Therefore, the projecting contour portion has a first-order differential coefficient of a function representing a radius of curvature with a contour length from any one point to each point as a variable on the contour of the cross section of the glass fiber 10 perpendicular to the spinning direction. A diameter of a perfect circle having a specific point (hereinafter referred to as a protrusion point) that is zero and whose second derivative is negative, and whose diameter is the same area as the cross section around the protrusion point It means a portion of the cross section of the glass fiber 10 having a point other than the protruding point on the contour where the radius of curvature is positive within a perfect circle which is a quarter.

  In this way, when the glass fiber 10 is filled into a resin material and compounded, the meshing between the glass fibers 10 and between the glass fiber 10 and the resin material is further strengthened. Further improvement can be expected. On the other hand, when there is no point other than the specific protrusion point on the contour with a positive curvature radius within a quarter of the diameter of the perfect circle having the same area as the cross section from the specific protrusion point described above That is, when the point other than the specific protruding point on the contour where the radius of curvature is positive is farther than a quarter, the portion protruding outwardly recognized in the contour of the cross section of the glass fiber 10 Becomes a gentle shape, and there is a possibility that the meshing with the composite material or the surrounding glass fiber 10 becomes insufficient.

  Further, the modified cross-section glass fiber 10 has a shape having two or more projecting contour portions in the cross-sectional contour shape and different dimensions from the center of gravity of the cross-sectional contour shape to the tip of the projecting contour portion. Is preferred. In this way, when the glass fiber 10 and the resin material are combined, the protruding contour portion of the glass fiber is not oriented in a specific direction, and it is easy to face an unspecified direction, and the formed composite material It is easy to obtain isotropy in terms of mechanical performance. That is, the meshing structure described above is present at random, resulting in a more uniform and strong structure. Further, since the center of gravity is at a position where the dimension from the center of gravity of the cross-sectional contour shape to the projection point at the tip of the projecting contour portion is different, the projecting contour of the glass fiber 10 is combined when the glass fiber 10 and the resin material are combined. Without the portion being oriented in a specific direction, it becomes easier to face an unspecified direction, and the mechanical performance and the like of the formed composite material can easily obtain isotropic properties.

  Specifically, as shown in FIG. 5, the glass fiber 10 shown in FIG. 1 has eight protruding points M1 to M8 on its contour W. In other words, in this glass fiber 10, the first-order differential coefficient is 0 with respect to the function of expressing the radius of curvature of each point as a parameter with respect to the contour W of the cross section perpendicular to the spinning direction. Has projection points M1 to M8 that are negative. When each of the perfect circles C1 to C6, which is a quarter of the diameter of the perfect circle having the same area as the cross section around the six protrusion points M1 to M6, is virtually drawn, C1, C3 And V1 exists in the circle of C5, but the center of the radius of curvature at V1 is outside the contour W of the glass fiber 10. Further, V2 exists in the circles C2, C4, and C6, but the center of the radius of curvature at V2 is also outside the contour W of the glass fiber 10. That is, the contour W has six projecting contour portions including the projecting points M1 to M6. Moreover, in this glass fiber 10, the external appearance of the outline of the whole glass fiber 10 is exhibiting the flat shape long in one direction. For example, the difference from the two protrusion points M1 and M2 to the center of gravity P and the length of q1 and q2 are within 10%. From the third protrusion point M3 and the fourth protrusion point M4 to the center of gravity P. The distances q3 and q4 are smaller than q1 and q2. With such a configuration, the protruding portion has a shape that protrudes outwardly with the outline of the cross section of the glass fiber, and when used together with the resin material, the resin material is connected in a wedge shape and meshed It is a shape that can be used, and contributes to improvement of mechanical strength when used as a composite material.

  Further, the glass fiber 10 is formed so that the cross-sectional area of the modified cross-section glass fiber 10 is less than 1/1000 of the opening area of the lower end opening portion of the nozzle hole 22 serving as the outlet end of the molten glass G in the nozzle 21. It is preferable to manufacture. If it does in this way, the stable cooling conditions are employ | adopted and the non-circular glass fiber 10 of a desired external dimension can be shape | molded so that it may become a high dimensional accuracy. From this point of view, the area of the cross section of the modified cross-section glass fiber 10 to be produced is more preferably less than 1/2000 of the opening area of the nozzle hole 22 of the nozzle 21 and less than 1/5000. More preferably, it is most preferably less than 1/10000.

DESCRIPTION OF SYMBOLS 10 Modified cross-section glass fiber 11a, 11b Main surface 12 Protrusion part 20 Bushing 21 Heat-resistant nozzle 21a Heat-resistant nozzle protrusion part 21b Heat-resistant nozzle notch part 22 Nozzle hole 30 Winding device G Molten glass P Center of gravity of irregular cross-section glass fiber P1 Center of gravity of nozzle hole R1, R2 Curvature radii C1, C2, C3, C4 True circles having a diameter equal to one-fourth of a perfect circle having the same area as the cross-sectional area of the glass fiber centering on the projection point Q1, Q2, Q3 , Q4, Q5, Q6, Q7, Q8 Virtual lines from the center of gravity to the projection point q1, q2, q3, q4 Each dimension of Q1-Q4 M1, M2, M3, M4, M5, M6, M7, M8 Projection point V1 The center of the radius of curvature in C1, C3, C5 is outside the cross section V2 The point of the center of the radius of curvature in C2, C4, C6 is outside the cross section L An irregular cross section glass fiber The long axis of the transverse cross section of the fiber S The short axis of the cross section of the irregular shaped glass fiber T The long axis of the nozzle hole U The plane including the major axis of the nozzle hole and parallel to the spinning direction of the molten glass W The irregular shaped glass fiber Contour line of cross section

Claims (4)

The cross section perpendicular to the spinning direction is a modified cross-section glass fiber having a flat shape,
Formed of E glass,
In the cross section, having a pair of main surfaces extending in the direction of the major axis passing through the center of gravity and facing in the direction of the minor axis passing through the center of gravity and orthogonal to the major axis,
Only the one main surface has a protrusion, and the protrusion is formed at both ends in the major axis direction,
Of the one main surface, the non-projection portion formed between the projection portions is substantially linear, and the formation region of the non-projection portion is longer than the formation region of the projection portion. A modified cross-section glass fiber characterized by being wide in the direction.   The deformed glass fiber according to claim 1, wherein a flatness ratio of the cross section is in a range of 1.5 or more and 10.0 or less.   The deformed glass fiber according to claim 1 or 2, wherein a perfect circle equivalent diameter of the cross section is in a range of 5 µm to 30 µm. When the position of the center of the radius of curvature at each point of the contour of the cross section of the radius of curvature and negative when the inside the cross-section was the curvature radius is positive when outside the cross-section, said transverse in function representing the radius of curvature of the contour length and a variable of an arbitrary one point of the contour of the surface to each point as a starting point, the first derivative is a zero, the projection point where the secondary differential coefficient is negative It has on the outline of the said cross section, The deformed glass fiber of any one of Claims 1-3 characterized by the above-mentioned.