JP2018095976A - Glass fiber nonwoven fabric, complex, fiber-reinforced thermoplastic resin sheet, metal-clad laminated sheet, method for producing glass fiber nonwoven fabric and method for producing fiber-reinforced thermoplastic resin sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonwoven fabric that can be used as a supply source of fibers of a fiber-reinforced thermoplastic resin sheet with reduced thermal expansion in thickness direction.SOLUTION: A glass fiber nonwoven fabric contains glass long fibers with a length of 3-25 mm and glass short fibers with a length of 0.3-1 mm, in a mass ratio of 50:50-90:10. The glass long fibers are oriented horizontally with respect to the plane direction of the glass fiber nonwoven fabric, and at least part of the glass short fibers is inserted inside at an angle of 60-120 degrees with respect to the plane direction of the glass fiber nonwoven fabric.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a glass fiber nonwoven fabric, a composite, a fiber reinforced thermoplastic resin sheet, a metal-clad laminate sheet, a method for producing a glass fiber nonwoven fabric, and a method for producing a fiber reinforced thermoplastic resin sheet.

  A sheet obtained by heating and pressing a composite containing fibers and resin is also called a fiber-reinforced resin sheet, and has advantages such as higher mechanical strength than a resin sheet containing no fibers. . For this reason, the fiber reinforced resin sheet is used in various fields such as the electric and electronic fields and the automobile industry field. For example, as a fiber reinforced resin sheet, Patent Document 1 discloses a binder resin (A), a fibrous filler (B) having an aspect ratio of 100 or more, and a filler having an aspect ratio smaller than that of the fibrous filler (B). (C) and a resin sheet in which the fibrous filler (B) is arranged in a plane direction is disclosed.

Japanese Unexamined Patent Publication No. 2016-130279

  As one of the uses of a fiber reinforced resin sheet, the use as a base material (insulating sheet) of a wiring board or a metal-clad laminated sheet is known. In this application, a thermosetting resin represented by an epoxy resin is widely used as a matrix resin material. However, thermosetting resins generally tend to have lower moldability than thermoplastic resins. On the other hand, a thermoplastic resin having a melting point and a thermal decomposition temperature higher than a general reflow soldering temperature (for example, 260 ° C.) and excellent in heat resistance, such as polyetherimide, has been developed. Some of these thermoplastic resins have excellent characteristics such as low smoke generation and low dielectric constant, which could not be realized by thermosetting resins represented by epoxy resins that have been used so far. It is preferable if it can be used as a resin material for a tension laminate sheet.

  However, according to the study of the inventor of the present invention, the fiber reinforced resin sheet using a thermoplastic resin as a matrix resin material is in the thickness direction of the sheet under a high temperature environment as compared with that using a thermosetting resin. It has been found that it is likely to thermally expand. If the substrate of the wiring board or metal-clad laminate sheet repeats thermal expansion and contraction in the thickness direction, the wiring (metal foil) may be peeled off from the substrate and cause a disconnection. In addition, in a laminated wiring board in which a plurality of wiring boards are laminated, each wiring board constituting the laminated wiring board repeats thermal expansion and contraction in the thickness direction, which may cause the wiring board to peel off and break. is there. Therefore, it is desirable that the fiber-reinforced resin sheet used as the base material of the wiring board or the copper-clad laminate sheet has a low thermal expansion in the thickness direction under a high temperature environment.

  The present invention has been made in view of the above circumstances, and is a fiber-reinforced thermoplastic having a reduced thermal expansion in the thickness direction under a high temperature environment while using a thermoplastic resin as a matrix resin component. An object is to provide a resin sheet and a metal-clad laminate sheet using this fiber-reinforced thermoplastic resin sheet. Another object of the present invention is to provide a composite containing a thermoplastic matrix resin and fibers, which can be used as a material (prepreg) for producing the fiber-reinforced thermoplastic resin sheet. Another object of the present invention is to provide a nonwoven fabric that can be used as a fiber supply source of the fiber-reinforced thermoplastic resin sheet. Still another object of the present invention is to provide a method for producing the above-described glass fiber nonwoven fabric and a method for producing a fiber-reinforced thermoplastic resin sheet.

  The inventor of the present invention dispersed a glass long fiber having a length of 3 to 25 mm and a glass short fiber having a length of 0.3 to 1 mm in water at a mass ratio of 50:50 to 90:10. By making the glass fiber aqueous dispersion, the long glass fibers are oriented horizontally with respect to the plane direction, and at least a part of the short glass fibers are at an angle of 60 to 120 degrees with respect to the plane direction. The knowledge that it is possible to manufacture the inserted glass fiber nonwoven fabric was obtained. And it discovered that the glass fiber nonwoven fabric containing the glass short fiber which has said angle becomes a supply source of a fiber useful for reducing the thermal expansion to the thickness direction of the thermoplastic resin sheet in a high temperature environment. It was. That is, the fiber-reinforced thermoplastic resin sheet, which is a heat-pressed molded body of a composite containing the above glass fiber nonwoven fabric and thermoplastic resin, significantly reduces thermal expansion in the thickness direction under a high temperature environment. As a result, the present invention has been completed. The reason why the thermal expansion in the thickness direction of the fiber reinforced thermoplastic resin sheet in a high temperature environment is reduced by using this glass fiber nonwoven fabric is not necessarily clear, but the glass fiber nonwoven fabric has the above angle. This is considered to be because the short glass fibers inserted in this manner suppress the expansion of the thermoplastic resin in the thickness direction.

Therefore, in order to achieve the above-described problem, the present invention employs the following configuration.
[1] A glass fiber nonwoven fabric comprising glass long fibers having a length of 3 to 25 mm and short glass fibers having a length of 0.3 to 1 mm in a mass ratio of 50:50 to 90:10, The long glass fibers are oriented horizontally with respect to the planar direction of the glass fiber nonwoven fabric, and at least some of the short glass fibers have an angle of 60 to 120 degrees with respect to the planar direction of the glass fiber nonwoven fabric. A glass fiber nonwoven fabric characterized by being inserted inside.
[2] The glass fiber according to the item [1], wherein 30% or more of the short glass fibers are inserted into the glass fiber nonwoven fabric at an angle of 60 to 120 degrees with respect to a planar direction of the glass fiber nonwoven fabric. Non-woven fabric.
[3] The glass fiber according to the item [1] or [2], wherein 80% or more of the long glass fibers are oriented at an angle of ± 30 degrees or less with respect to a planar direction of the glass fiber nonwoven fabric. Non-woven fabric.
[4] The glass fiber nonwoven fabric according to any one of [1] to [3], which is a wet nonwoven fabric.

[5] A composite comprising the glass fiber nonwoven fabric according to any one of [1] to [4] and a thermoplastic matrix resin.
[6] The composite according to [5], wherein the matrix resin is arranged in a layered manner on at least one surface of the glass fiber nonwoven fabric.
[7] The composite according to [5], wherein the matrix resin is disposed in the form of beads or fibers inside the glass fiber nonwoven fabric.
[8] A fiber-reinforced thermoplastic resin sheet that is a heat-pressed molded body of the composite according to any one of [5] to [7].
[9] A metal-clad laminate sheet comprising the fiber-reinforced thermoplastic resin sheet according to [8] above and a metal foil bonded to at least one surface of the fiber-reinforced thermoplastic resin sheet.

[10] Glass in which long glass fibers having a length of 3 to 25 mm and short glass fibers having a length of 0.3 to 1 mm are dispersed in water at a mass ratio of 50:50 to 90:10 The manufacturing method of the glass fiber nonwoven fabric which has the process of preparing a fiber aqueous dispersion, and the process of paper-making the said glass fiber aqueous dispersion.
[11] A glass fiber nonwoven fabric comprising glass long fibers having a length of 3 to 25 mm and short glass fibers having a length of 0.3 to 1 mm in a mass ratio of 50:50 to 90:10, The long glass fibers are oriented horizontally with respect to the planar direction of the glass fiber nonwoven fabric, and at least some of the short glass fibers have an angle of 60 to 120 degrees with respect to the planar direction of the glass fiber nonwoven fabric. A method for producing a fiber-reinforced thermoplastic resin sheet, comprising a step of preparing a composite comprising a glass fiber nonwoven fabric inserted therein and a thermoplastic matrix resin, and a step of heat-pressing the composite.

  According to the present invention, a fiber reinforced thermoplastic resin sheet having a reduced thermal expansion in the thickness direction under a high temperature environment while using a thermoplastic resin as a matrix resin component, and the fiber reinforced thermoplastic resin sheet It becomes possible to provide a metal-clad laminate sheet using the. In addition, the composite of the present invention can be advantageously used as a material (prepreg) for producing the fiber-reinforced thermoplastic resin sheet. Furthermore, the nonwoven fabric of the present invention can be advantageously used as a fiber supply source of the fiber-reinforced thermoplastic resin sheet. Furthermore, according to the manufacturing method of the glass fiber nonwoven fabric of this invention, said glass fiber nonwoven fabric can be manufactured industrially advantageously. And according to the manufacturing method of the fiber reinforced thermoplastic resin sheet of this invention, said fiber reinforced thermoplastic resin sheet can be manufactured industrially advantageously.

It is explanatory drawing explaining the structure of the glass fiber nonwoven fabric which is one Embodiment of this invention. It is sectional drawing of an example of the composite_body | complex which is one Embodiment of this invention. It is sectional drawing of another example of the composite_body | complex which is one Embodiment of this invention. It is a cross section of another example of the composite_body | complex which is one Embodiment of this invention. It is sectional drawing of an example of the fiber reinforced thermoplastic resin sheet which is one Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Glass fiber nonwoven fabric>
Drawing 1 is an explanatory view explaining the composition of the glass fiber nonwoven fabric which is one embodiment of the present invention, (a) is a sectional view of glass fiber nonwoven fabric, and (b) is a top view of glass fiber nonwoven fabric. .

  As shown in FIG. 1, the glass fiber nonwoven fabric 10 of this embodiment includes long glass fibers 11 and short glass fibers 12. The long glass fiber 11 is a glass fiber having a length in the range of 3 to 25 mm. The short glass fiber 12 is a glass fiber having a length in the range of 0.3 to 1 mm. The diameter of the long glass fiber 11 and the short glass fiber 12 is generally in the range of 3 to 18 μm, preferably in the range of 6 to 15 μm, more preferably in the range of 6 to 13 μm. The aspect ratio (length / diameter) of the long glass fiber 11 is generally in the range of 100 to 20000, preferably in the range of 160 to 18000, more preferably in the range of 200 to 15000. When the glass fiber nonwoven fabric in which the diameter and aspect ratio of the glass long fiber 11 and the glass short fiber 12 are in the above ranges is used, the thermal expansion in the thickness direction of the fiber reinforced thermoplastic resin sheet can be more reliably reduced. .

  The content ratio of the glass long fiber 11 and the glass short fiber 12 in the glass fiber nonwoven fabric 10 is preferably in the range of 50:50 to 95: 5 (glass long fiber: glass short fiber), more preferably 55: It is in the range of 45 to 95: 5, particularly preferably in the range of 60:40 to 90:10. That is, the content of the short glass fiber 12 with respect to the total content of the long glass fiber 11 and the short glass fiber 12 is preferably in the range of 5 to 50% by mass, more preferably in the range of 5 to 45% by mass, and particularly preferably 10%. It is in the range of ˜40% by mass. When the glass fiber nonwoven fabric in which the content ratio of the glass long fibers 11 and the glass short fibers 12 is in the above range is used, the thermal expansion in the thickness direction of the fiber reinforced thermoplastic resin sheet can be more reliably reduced.

The content ratio of the long glass fiber 11 and the short glass fiber 12 in the glass fiber nonwoven fabric 10 can be determined, for example, as follows.
Using an optical microscope, the glass fiber nonwoven fabric 10 is observed, and a total of 100 fibers (including glass long fibers 11 and glass short fibers 12) are arbitrarily selected from one observation area. The number of long glass fibers 11 and short glass fibers 12 is counted, and the length and diameter of each fiber are measured. The number average of the measured lengths and diameters of the long glass fiber 11 and the short glass fiber 12 is obtained. Using the obtained average length and average diameter, the content of the long glass fiber 11 and the content of the short glass fiber 12 are calculated from the following formulas. And the ratio of content of the calculated glass long fiber 11 and content of the glass short fiber 12 is calculated | required.
Content of long glass fiber 11 = average length × (average diameter / 2) ² × π × density of long glass fiber 11 × number of long glass fibers 11 in 100 fibers Content of short glass fiber 12 = average Length × (average diameter / 2) ² × π × density of short glass fibers 12 × number of short glass fibers 12 in 100 fibers

Most of the long glass fibers 11 are oriented horizontally with respect to the planar direction of the glass fiber nonwoven fabric 10 as shown in FIG. Here, "are oriented horizontally", in addition to the case where the angle theta ₁ with respect to the plane direction is oriented such that 0 degrees, as the angle theta ₁ is within ± 30 degrees to the plane direction Includes the case of orientation. The amount of the long glass fibers 11 oriented so that the angle θ ₁ with respect to the plane direction is within ± 30 degrees is preferably 80% or more, and 90% or more with respect to the total amount of the long glass fibers. It is more preferable that When the glass fiber nonwoven fabric in which the glass long fibers 11 are oriented in the plane direction within the above angle is used, the strength in the plane direction of the fiber-reinforced thermoplastic resin sheet can be increased and the thermal expansion in the plane direction can be reduced. it can.

As shown in FIG. 1A, at least a part of the short glass fiber 12 is inserted into the glass fiber nonwoven fabric 10 at an angle θ _{2 of} 60 to 120 degrees with respect to the planar direction of the glass fiber nonwoven fabric 10. Here, “inserted into the inside” means that a length of ½ or more of the length of the glass short fiber 12 is inside the glass fiber nonwoven fabric 10. The amount of the short glass fibers 12 inserted into the glass fiber nonwoven fabric 10 at an angle of 60 to 120 degrees with respect to the planar direction of the glass fiber nonwoven fabric 10 may be 30% or more with respect to the total amount of the short glass fibers. Preferably, it is 40% or more. By using the glass fiber nonwoven fabric inserted into the glass fiber nonwoven fabric in a state where the short glass fibers 12 are oriented in the direction perpendicular to or near the plane direction as described above, that is, in the thickness direction. The thermal expansion in the thickness direction of the fiber reinforced thermoplastic resin sheet is reduced.

  On the other hand, in this embodiment, there is no restriction | limiting in particular in the orientation direction of the glass long fiber 11 and the glass short fiber 12 when the glass fiber nonwoven fabric 10 is planarly viewed. As shown in FIG.1 (b), the orientation direction of the glass long fiber 11 and the glass short fiber 12 may be random.

  It is preferable that the glass fiber nonwoven fabric 10 of this embodiment is a wet nonwoven fabric. When it is a wet nonwoven fabric, the long glass fibers 11 tend to be oriented in the planar direction, and the short glass fibers 12 tend to be easily oriented in the thickness direction. In addition, the manufacturing method of the glass fiber nonwoven fabric 10 is mentioned later.

  The glass fiber nonwoven fabric 10 may contain glass fibers other than the long glass fibers 11 and the short glass fibers 12. That is, the glass fiber nonwoven fabric 10 may include glass fibers having a length of less than 0.3 mm, glass fibers having a length of more than 1 mm and less than 3 mm, and glass fibers having a length of more than 25 mm.

  In the glass fiber nonwoven fabric 10, the total content of the long glass fibers 11 and the short glass fibers 12 is preferably 80% by mass or more, and particularly preferably 90% by mass or more. The content of glass fibers having a length of less than 0.3 mm is preferably 3% by mass or less. The content of glass fibers having a length exceeding 1 mm and less than 3 mm is preferably 20% by mass or less, and particularly preferably 10% by mass or less. The content of the glass fiber having a length exceeding 25 mm is preferably 20% by mass or less, and particularly preferably 10% by mass or less.

<Method for producing glass fiber nonwoven fabric>
The manufacturing method of the glass fiber nonwoven fabric which is one Embodiment of this invention has the process of preparing a glass fiber aqueous dispersion, and the process of paper-making this glass fiber aqueous dispersion.

  The glass fiber aqueous dispersion is dispersed in water at a ratio of 50:50 to 90:10 in terms of mass ratio of glass fibers having a length of 3 to 25 mm and glass fibers having a length of 0.3 to 1 mm. It is a dispersion liquid. The aqueous glass fiber dispersion can be prepared by mixing long glass fibers, short glass fibers, and water and stirring them. The order of mixing is not particularly limited, and glass short fibers may be added after mixing water and glass long fibers, or glass long fibers may be added after mixing water and glass short fibers, or water. And long glass fibers and short glass fibers may be mixed simultaneously.

  As a raw material of the glass long fiber, a glass fiber having a mass average fiber length generally in the range of 3 to 25 mm, preferably in the range of 6 to 18 mm, more preferably in the range of 6 to 15 mm may be used. Further, as a raw material for short glass fibers, the mass average length is generally in the range of 0.3 to 1 mm, preferably in the range of 0.3 to 0.8 mm, more preferably in the range of 0.3 to 0.7 mm. Short glass fibers may be used.

  In the glass fiber aqueous dispersion, a dispersant may be added in order to suppress aggregation of the long glass fiber and the short glass fiber. Moreover, a thickener may be added to the glass fiber aqueous dispersion.

  Papermaking of the aqueous glass fiber dispersion can be carried out using a known papermaking machine that is used in the production of general wet nonwoven fabrics. As the paper machine, either a batch type paper machine or a continuous type paper machine can be used.

  The batch type paper machine is a paper machine that repeats the steps of supplying an aqueous glass fiber dispersion to a container for raw materials, forming a fiber layer by paper making (dehydration), and collecting the fiber layer as one cycle. When using a batch type paper machine, the concentration of the solid content of the aqueous glass fiber dispersion (total amount of long glass fibers and short glass fibers) in the container for the raw material is preferably 1% by mass or less, More preferably, it is in the range of 0.001 to 0.7 mass%. When the solid content concentration of the aqueous glass fiber dispersion is within the above range, the degree of freedom of movement of the fibers in the aqueous glass fiber dispersion increases, and a sufficient dehydration rate can be obtained during dehydration. For this reason, long glass fibers can be easily oriented in the horizontal direction, and short glass fibers can be easily oriented in the thickness direction.

  It is preferable that the viscosity of the glass fiber aqueous dispersion in the container for raw material is in the range of 0.9 mPa · s to 3.0 mPa · s by adding the above-described thickener. When the viscosity of the glass fiber aqueous dispersion is within this range, the glass fiber nonwoven fabric is excellent in dispersibility of glass fibers (particularly, long glass fibers) and has little glass fiber breakage and breakage even if the Reynolds number is the same. Tends to be manufactured with high productivity. On the other hand, if the viscosity of the aqueous glass fiber dispersion is too low, the glass fibers tend to aggregate and the dispersibility of the glass fibers may be reduced. On the other hand, if the viscosity of the aqueous glass fiber dispersion is too high, the dehydration resistance may increase, leading to a decrease in productivity. For this reason, it is preferable that the viscosity is set in consideration of suppression of aggregation of the glass fibers and productivity. That is, if the viscosity of the glass fiber aqueous dispersion is 1.1 mPa · s, aggregation of glass fibers can be suppressed, and if it is 1.0 mPa · s or less, productivity can be improved. The viscosity of the glass fiber aqueous dispersion was measured by collecting the filtrate from which the glass fiber was removed by filtering the glass fiber aqueous dispersion with an 80 mesh filter (Fluy), and using a Canon-Fenske viscometer. It can be measured according to the measurement method prescribed in “Method for measuring viscosity of liquid”.

  The continuous paper machine is a paper machine that continuously performs the steps of supplying an aqueous glass fiber dispersion to an inlet, forming a fiber layer by paper making (dehydration), and collecting the fiber layer. Examples of the continuous paper machine include an inclined paper machine, a circular net paper machine, and a long net paper machine. Among these paper machines, it is preferable to use an inclined paper machine that can reduce the solid content concentration of the aqueous glass fiber dispersion in the inlet and rapidly dehydrate it. This is because the short glass fibers are easily oriented in the thickness direction by the water flow due to rapid dehydration. When using an inclined paper machine, the solid content concentration of the glass fiber aqueous dispersion in the inlet is preferably in the range of 0.001 to 0.5 mass%, 0.002 to 0.3 mass%. More preferably, it is in the range, more preferably in the range of 0.008 to 0.1% by mass. By setting the solid content concentration of the aqueous glass fiber dispersion in the inlet to such a concentration range, a sufficient dehydration rate can be obtained, so that the short glass fibers can be sufficiently oriented in the thickness direction. Moreover, since the dehydration load does not become too high, a glass fiber nonwoven fabric can be produced with high energy efficiency. The viscosity of the glass fiber aqueous dispersion in the inlet is preferably in the range of 0.9 mPa · s to 3.0 mPa · s, as in the case of using the batch type paper machine. As the filter medium of the paper machine, one having an opening of 30 to 150 mesh can be used.

Next, the fiber layer (wet sheet) collected from the paper machine is dried to obtain a glass fiber nonwoven fabric. For drying the wet sheet, a heating dryer such as a hot air dryer can be used.
By doing as mentioned above, the glass fiber nonwoven fabric in which the long glass fibers are oriented in the plane direction and at least a part of the short glass fibers are oriented in the thickness direction can be produced.

<Composite>
A composite according to an embodiment of the present invention is a composite including the above-described glass fiber nonwoven fabric and a thermoplastic matrix resin. The content of the glass fiber nonwoven fabric and the matrix resin is preferably in the range of 50:50 to 10:90 (glass fiber nonwoven fabric: matrix resin), more preferably in the range of 45:55 to 15:85, particularly preferably in mass ratio. The range is 45:55 to 20:80. That is, the content of the matrix resin with respect to the total amount of the glass fiber nonwoven fabric and the matrix resin is preferably in the range of 50 to 90% by mass, more preferably in the range of 55 to 85% by mass, particularly preferably in the range of 55 to 80% by mass. It is in. When the content ratio of the glass fiber nonwoven fabric and the matrix resin is within the above range, the characteristics of the matrix resin (for example, low dielectric constant and low dielectric loss) and the characteristics of the nonwoven fabric (for example, thermal expansion in a high temperature environment) And the like can be expressed in a balanced manner.

  The thermoplastic matrix resin may be disposed in layers on the surface of the glass fiber nonwoven fabric, may be disposed in the form of beads or fibers inside the glass fiber nonwoven fabric, and further, the surface of the glass fiber nonwoven fabric. You may arrange | position both inside. Further, thermoplastic matrix resin beads and fibers may be used in combination.

  FIG. 2 is a cross-sectional view of an example of a composite body that is an embodiment of the present invention. In FIG. 2, the thermoplastic matrix resin is arranged as a matrix resin layer 20 on the surface of the glass fiber nonwoven fabric 10. In FIG. 2, the matrix resin layer 20 is disposed on one surface (the upper surface in FIG. 2) of the glass fiber nonwoven fabric 10, but may be disposed on both surfaces of the glass fiber nonwoven fabric 10. The matrix resin layer 20 may be merely laminated on the surface of the glass fiber nonwoven fabric 10 or may be bonded.

  The composite in which the glass fiber nonwoven fabric 10 and the matrix resin layer 20 are bonded is obtained by, for example, laminating a glass fiber nonwoven fabric and a thermoplastic matrix resin sheet, and heating and pressurizing the obtained laminate to form a matrix resin sheet. Can be manufactured by fusing to a glass fiber nonwoven fabric.

  FIG. 3 is a cross-sectional view of another example of the composite body according to the embodiment of the present invention. In FIG. 3, the thermoplastic matrix resin is arranged as matrix resin beads 21 inside the glass fiber nonwoven fabric 10. The shape of the matrix resin beads 21 is preferably a sphere, an elliptic sphere, or a cylinder. The matrix resin beads 21 have a major axis length of preferably 0.1 to 2.0 mm, more preferably 0.3 to 1.0 mm, and 0.4 to 0.7 mm. It is especially preferable that it is in the range.

  The composite of FIG. 3 is prepared, for example, by preparing a matrix resin bead-containing glass fiber aqueous dispersion containing long glass fibers 11, short glass fibers 12, and thermoplastic matrix resin beads 21, and the prepared dispersion is made into paper. Can be manufactured. The aqueous glass fiber dispersion containing the matrix resin beads can be prepared by mixing the aqueous glass fiber dispersion and the matrix resin beads 21 used in the above-described method for producing a glass fiber nonwoven fabric. In the aqueous dispersion of glass fiber beads-containing glass fiber, the concentration of the solid content (the total of the long glass fiber 11, the short glass fiber 12, and the matrix resin bead 21) is preferably 1% by mass or less, and 0.001 to 0 More preferably, it is in the range of 7% by mass. Papermaking can be carried out under the same conditions as in the method for producing a glass fiber nonwoven fabric described above.

  FIG. 4 is a cross-sectional view of still another example of a composite body that is an embodiment of the present invention. In FIG. 4, the thermoplastic matrix resin is arranged as matrix resin fibers 22 inside the glass fiber nonwoven fabric 10. That is, this composite constitutes a nonwoven fabric-like composite including the long glass fibers 11, the short glass fibers 12, and the matrix resin fibers 22. The matrix resin fibers 22 preferably have a mass average fiber length in the range of 1.0 to 30 mm and a fiber diameter in the range of 0.1 to 100 dtex. The mass average fiber length of the matrix resin fibers 22 is more preferably in the range of 3.0 to 25 mm. The fiber diameter is more preferably in the range of 1.0 to 3.0 dtex. In the present specification, the mass average fiber length is a mass average value of fiber lengths measured for 100 matrix resin fibers.

  The non-woven composite of FIG. 4 is prepared by preparing a matrix resin fiber-containing glass fiber aqueous dispersion containing, for example, long glass fibers 11, short glass fibers 12, and thermoplastic matrix resin fibers 22, and this prepared dispersion. The liquid can be produced by papermaking. The matrix resin fiber-containing glass fiber aqueous dispersion can be prepared by mixing the glass fiber aqueous dispersion and the matrix resin fiber 22 used in the above-described method for producing a glass fiber nonwoven fabric. The matrix resin fiber-containing glass fiber aqueous dispersion preferably has a solid content (total of glass long fibers 11, glass short fibers 12, and matrix resin fibers 22) of 1% by mass or less, 0.001 to 0. More preferably, it is in the range of 7% by mass. Papermaking can be carried out under the same conditions as in the method for producing a glass fiber nonwoven fabric described above.

The thermoplastic matrix resin contained in the composite of the present embodiment can be appropriately selected depending on the application. For example, when the composite (prepreg) of the present embodiment is used as an intermediate of an insulating sheet of a wiring board or a metal-clad laminate sheet, the thermoplastic matrix resin is obtained by heating the composite containing the thermoplastic matrix resin. It is preferably a resin that does not melt, deform, and thermally decompose at a temperature equal to or lower than the reflow temperature of soldering in the state of the compacted body.
The phrase “not melted, deformed and thermally decomposed at a temperature lower than the soldering reflow temperature” means that the material does not melt, deform and thermally decompose when heated for at least 1 minute at the soldering reflow temperature.
The matrix resin used in the present invention, which is a thermoplastic resin, has a glass transition temperature sufficiently high in the case of an amorphous thermoplastic resin having a melting point higher than the soldering reflow temperature or no melting point. In the state of the molded body, it is preferable that the molded body does not deform when heated at the soldering reflow temperature for at least 1 minute. The melting point or glass transition temperature of the matrix resin cannot be determined uniformly because the reflow temperature of soldering varies depending on conditions such as the type of solder used and the type of components to be mounted, but is preferably 220 ° C. or more, more preferably Is 260 ° C. or higher, more preferably 280 ° C. or higher. In the case where the matrix resin is an amorphous thermoplastic resin, even if the glass transition temperature is lower than the reflow temperature for soldering, in the state of the molded body described above, the reflow temperature for soldering is due to the reinforcing effect of the glass fiber. In some cases, melting, deformation, or thermal decomposition does not occur even when heated, and in such a case, the thermoplastic resin can be used in the present invention.
Examples of such thermoplastic resins include polyetherimide (PEI), polyetheretherketone (PEEK), and polyphenylene sulfide (PPS). These thermoplastic resins may be used individually by 1 type, and may be used in combination of 2 or more type.

  The composite may contain a binder resin in order to improve the adhesion between the thermoplastic matrix resin and the glass fiber nonwoven fabric. The binder resin is preferably a resin that is compatible with the matrix resin when the composite is heated and pressed. Examples of the binder resin include polyvinyl alcohol (PVA). When the thermoplastic matrix resin is disposed in a layered manner on the surface of the glass fiber nonwoven fabric, the binder resin is preferably disposed in a layered manner between the matrix resin layer and the surface of the glass fiber nonwoven fabric. Further, when the thermoplastic matrix resin is arranged in the form of beads or fibers inside the glass fiber nonwoven fabric, the binder resin is preferably arranged in the form of beads or fibers inside the glass fiber nonwoven fabric.

<Glass fiber reinforced thermoplastic resin sheet>
The glass fiber reinforced thermoplastic resin sheet of the present invention is a heat and pressure molded body obtained by heat and pressure molding the above-mentioned composite. Therefore, the glass fiber reinforced thermoplastic resin sheet of the present invention includes long glass fibers, short glass fibers, and a thermoplastic matrix resin.

  FIG. 5 is a cross-sectional view of an example of a glass fiber reinforced thermoplastic resin sheet according to an embodiment of the present invention. The glass fiber reinforced thermoplastic resin sheet 30 includes a thermoplastic matrix resin 23, and long glass fibers 11 and short glass fibers 12 contained in the matrix resin 23. The long glass fiber 11 and the short glass fiber 12 maintain the orientation of the glass fiber nonwoven fabric 10. That is, the long glass fiber 11 is oriented in the planar direction of the glass fiber reinforced thermoplastic resin sheet 30. In addition, at least a part of the short glass fibers 12 is oriented in the thickness direction of the glass fiber reinforced thermoplastic resin sheet 30. However, it is not necessary for all the long glass fibers 11 and the short glass fibers 12 to maintain the orientation in the state of the glass fiber nonwoven fabric 10.

  The glass fiber reinforced thermoplastic resin sheet 30 of the present embodiment has a low thermal expansion in the thickness direction under a high temperature environment. For this reason, it can be advantageously used as a substrate (insulating sheet) for a wiring board or a metal-clad laminate sheet.

The metal-clad laminate sheet is a sheet that includes a metal foil bonded to at least one surface of the glass fiber reinforced thermoplastic resin sheet 30. The metal-clad laminate sheet can be produced by heat and pressure molding in a state where a metal foil is stacked on at least one surface of the composite. Examples of the metal foil material include copper, aluminum, silver, and gold.
A wiring board can be obtained by patterning the copper foil of this metal-clad laminate sheet by a technique such as etching.

<Method for producing glass fiber reinforced thermoplastic resin sheet>
The glass fiber reinforced thermoplastic resin sheet can be produced by heat-pressing the above-described composite. The composite may be formed by heating and pressing only one sheet, or two or more sheets may be stacked by heating and pressing, and can be determined according to the use of the glass fiber reinforced thermoplastic resin sheet to be molded. The heating temperature is equal to or higher than the temperature at which the thermoplastic matrix resin contained in the composite is softened and exhibits plasticity. Since the optimum temperature range varies depending on conditions such as the type and content of the thermoplastic matrix resin, the heating temperature cannot be uniformly determined, but is usually in the range of 260 to 600 ° C, preferably 280 to 450 ° C. It is the range, More preferably, it is the range of 280 degreeC-400 degreeC.

The pressure of the pressurization can be appropriately set according to conditions such as the thickness of the composite and the thickness of the target glass fiber reinforced thermoplastic resin sheet. The pressure for pressurization is usually in the range of 3 to 50 MPa, preferably in the range of 5 to 20 MPa.
The heating and pressing time is not particularly limited, but is usually in the range of 1 to 100 minutes, preferably 1 to 30 minutes.

[Example 1]
(1) Preparation of glass fiber aqueous dispersion As a glass long fiber, a glass fiber chopped strand having a mass average fiber length of 10 mm and a mass average fiber diameter of 10 μm (Owens Corning, CS10JAJP195, length of 0.3 to 1.0 mm) Of glass short fiber: 0.1 mass% or less) was prepared. Moreover, what cut | disconnected said glass long fiber using scissors as glass short fiber, and prepared the length adjusted to the range of 0.5-1.0 mm was prepared.

40 g of the above-mentioned long glass fiber was weighed, and this was put into 20 L of water to which 0.12 g (0.3% by mass with respect to the long glass fiber) of a dispersant (Laccor AL, manufactured by Meisei Chemical Co., Ltd.) was added, The mixture was stirred and dispersed using a laboratory stirrer (manufactured by AS ONE, Ultra Stirrer DC-CHRM25) to obtain a glass long fiber aqueous dispersion. Next, 10 g of the above short glass fibers were added to this aqueous long glass fiber dispersion and stirred.
Thus, an aqueous glass fiber dispersion in which long glass fibers and short glass fibers were dispersed in water at a mass ratio of 80:20 was prepared. In addition, the glass fiber aqueous dispersion was prepared three times.

(2) Preparation of Matrix Resin Fiber-Containing Glass Fiber Aqueous Dispersion Into the glass fiber aqueous dispersion prepared in (1) above, 85 g of polyetherimide (PEI) fiber and 5 g of polyvinyl alcohol (PVA) fiber as a binder are added. And stirred using the laboratory stirrer. As the PEI fiber, a fiber having a mass average fiber length of 15 mm and a fiber diameter of 2.2 dtex (manufactured by Kuraray Co., Ltd.) was used. As the PVA fiber, one having a mass average fiber length of 3 mm (manufactured by Kuraray Co., Ltd., VPB105) was used.

Next, 2 L of a thickener aqueous solution having a thickener concentration of 0.1% by mass was added to the dispersion into which PEI fibers and PVA fibers were charged, and the mixture was stirred with the laboratory stirrer. As the thickener, an anionic polymer polyacrylamide type thickener (manufactured by MT Aqua Polymer Co., Ltd., Sumifloc) was used.
Finally, water was added so that the total amount was 28 kg, and stirred with the laboratory stirrer. Thus, a matrix resin fiber-containing glass fiber aqueous dispersion having a solid content concentration of 0.5% by mass in which glass fibers and matrix resin fibers are uniformly dispersed was prepared.

(3) Production of Nonwoven Fabric Composite Sheet 2500 g (solid content: 12.5 g) of the matrix resin fiber-containing glass fiber aqueous dispersion prepared in (2) above was collected. The separated dispersion liquid was put into a container for raw material of a 25 cm square hand-made sheet machine (manufactured by Kumagai Riki Kogyo Co., Ltd.). Next, water was added to the raw container so that the solid content concentration of the dispersion in the raw container was 0.15% by mass, and after sufficiently stirring so that the composition of the dispersion was uniform, Paper making was performed by a method according to JIS P 8222. And the obtained wet sheet was dried with a 160 degreeC hot air dryer, and the nonwoven fabric-like composite sheet (25 cm long x 25 cm wide, 200 g / m < ² > basis weight) was obtained.

[Example 2]
In the production of the nonwoven fabric-like composite sheet of Example 1 (Example 3), except that the amount of water charged into the container for the raw material was changed to an amount such that the solid content concentration of the dispersion was 0.08% by mass. In the same manner as in Example 1, a nonwoven fabric-like composite sheet (length 25 cm × width 25 cm, basis weight 200 g / m ² ) was obtained.

[Example 3]
In the production of the nonwoven fabric-like composite sheet of Example 1 (1), the amount of the dispersion added to the container for the raw material of the square handsheet sheet machine was 1250 g (solid content: 6.25 g), Non-woven composite sheet (25 cm long × 25 cm wide, basis weight) as in Example 1 except that the amount of water charged into the container was changed to an amount such that the solid content concentration of the dispersion was 0.04% by mass. 100 g / m ² ) was obtained.

[Example 4]
In the preparation of the aqueous glass fiber dispersion of Example 1 (1), the input amount of the long glass fiber is 45 g, the input amount of the short glass fiber is 15 g, and the long glass fiber and the short glass fiber are in a mass ratio of 75: An aqueous glass fiber dispersion dispersed at a ratio of 25 was prepared. In addition, in the production of the nonwoven fabric composite sheet of Example 1 (3), the amount of the dispersion to be introduced into the container for the raw material of the square handcrafted sheet machine was 1250 g (solid content: 6.25 g), The amount of water charged into the quality container was such that the solid content concentration of the dispersion was 0.04% by mass. Except for the above, a nonwoven fabric-like composite sheet (length 25 cm × width 25 cm, basis weight 100 g / m ² ) was obtained in the same manner as in Example 1.

[Example 5]
In the preparation of the aqueous glass fiber dispersion of Example 1 (1), the input amount of the long glass fiber is 30 g, the input amount of the short glass fiber is 30 g, and the long glass fiber and the short glass fiber have a mass ratio of 50: A glass fiber aqueous dispersion dispersed at a ratio of 50 was prepared. In addition, in the production of the nonwoven fabric composite sheet of Example 1 (3), the amount of the dispersion to be introduced into the container for the raw material of the square handcrafted sheet machine was 1250 g (solid content: 6.25 g), The amount of water charged into the quality container was such that the solid content concentration of the dispersion was 0.04% by mass. Except for the above, a nonwoven fabric-like composite sheet (length 25 cm × width 25 cm, basis weight 100 g / m ² ) was obtained in the same manner as in Example 1.

[Comparative Example 1]
In the preparation of the aqueous glass fiber dispersion of Example 1 (1), the glass fiber aqueous dispersion was prepared without adding glass short fibers, with the amount of glass long fibers charged being 60 g. In addition, in the production of the nonwoven fabric composite sheet of Example 1 (3), the amount of the dispersion to be introduced into the container for the raw material of the square handcrafted sheet machine was 1250 g (solid content: 6.25 g), The amount of water charged into the quality container was such that the solid content concentration of the dispersion was 0.04% by mass. Except for the above, a nonwoven fabric-like composite sheet (length 25 cm × width 25 cm, basis weight 100 g / m ² ) was obtained in the same manner as in Example 1.

[Comparative Example 2]
In the preparation of the aqueous glass fiber dispersion of Example 1 (1), the input amount of the long glass fiber is 25 g, the input amount of the short glass fiber is 35 g, and the long glass fiber and the short glass fiber are in a mass ratio of 42: A glass fiber aqueous dispersion dispersed at a ratio of 58 was prepared. In addition, in the production of the nonwoven fabric composite sheet of Example 1 (3), the amount of the dispersion to be introduced into the container for the raw material of the square handcrafted sheet machine was 1250 g (solid content: 6.25 g), The amount of water charged into the quality container was such that the solid content concentration of the dispersion was 0.04% by mass. Except for the above, a nonwoven fabric-like composite sheet (length 25 cm × width 25 cm, basis weight 100 g / m ² ) was obtained in the same manner as in Example 1.

[Evaluation]
The following evaluation was performed using the nonwoven fabric-like composite sheets obtained in the above Examples and Comparative Examples. The results are shown in Table 1 together with the blending ratio of each material used for the production of the nonwoven composite sheet, the basis weight of the nonwoven composite sheet, and the solid content concentration of the dispersion in the bulk container.

(Orientation of glass fiber of non-woven composite sheet)
The plane and cross section of the nonwoven composite sheet were observed using an optical microscope, and the orientation directions of the glass long fibers and the glass short fibers were confirmed. In the cross-sectional observation, the ratio of fibers oriented in the plane direction was measured for the long glass fibers, and the ratio of fibers oriented in the thickness direction was measured for the glass short fibers. The ratio of fibers oriented in the plane direction was the ratio of long glass fibers oriented at an angle within ± 30 degrees with respect to the plane direction. The ratio of fibers oriented in the thickness direction is the ratio of short glass fibers inserted in the interior at an angle of 60 to 120 degrees with respect to the plane direction of the nonwoven composite sheet, and the nonwoven composite The short glass fiber which protruded 1/2 or more of fiber length from the surface of the sheet | seat was excluded.

(Thermal expansion coefficient of glass fiber reinforced thermoplastic resin sheet)
A nonwoven fabric composite sheet was laminated to obtain a laminate. The number of laminated non-woven composite sheets was 14 in the case of Examples 1-2, and 28 in the case of Examples 3-5 and Comparative Examples 1-2. The laminate was heated and pressed under conditions of 300 ° C. and 10 MPa for 10 minutes using a heating and pressing apparatus, cooled to 70 ° C., and then taken out from the heating and pressing apparatus. The obtained glass fiber reinforced thermoplastic resin sheet was 25 cm long × 25 cm wide × 1.8 mm thick.

About the obtained glass fiber reinforced thermoplastic resin sheet, the thermal expansion coefficient in the plane direction and the thermal expansion coefficient in the thickness direction were measured.
The thermal expansion coefficient in the planar direction was measured in a tensile mode in accordance with JIS K 7197 under conditions of a heating rate of 5 ° C./min and a measurement temperature range of 30 to 210 ° C.
The thermal expansion coefficient in the thickness direction was measured according to JIS K 7197 in a compression mode under conditions of a temperature rising rate of 5 ° C./min and a measurement temperature range of 30 to 210 ° C.

(Shape stability of copper-clad laminated sheet under high temperature environment)
A nonwoven fabric composite sheet was laminated to obtain a laminate. The number of laminated non-woven composite sheets was 14 in the case of Examples 1-2, and 28 in the case of Examples 3-5 and Comparative Examples 1-2. A copper foil having a thickness of 18 μm was adhered to the bottom surface of the laminate. The obtained laminate with copper foil was subjected to heat and pressure molding under conditions of 300 ° C. and 10 MPa for 10 minutes using a heat and pressure press apparatus, cooled to 70 ° C., and then taken out from the heat and pressure press apparatus. The obtained copper-clad laminate sheet was 25 cm long × 25 cm wide × 1.8 mm thick.

  The obtained copper-clad laminate sheet was cut into 5 cm square. The obtained cut piece (length 5 cm × width 5 cm × thickness 1.8 mm) was put into a hot air dryer and heated at 260 ° C. for 3 minutes. Then, it took out from the hot air dryer and cooled to room temperature. The cut piece after cooling was allowed to stand on a flat substrate, and the distance from the substrate was measured at the four corners of the cut piece. A case where the distance was 1 mm or less at a distance of 1 mm or more was determined as “pass”, and a case where the distance was 2 or more was determined as “fail”.

  As shown in Table 1, the nonwoven fabric-like composite sheets obtained in Examples 1 to 5 are a glass fiber nonwoven fabric containing glass long fibers oriented in the plane direction and short glass fibers oriented in the thickness direction, and thermoplastic. It can be seen that the sheet is made of resin. And the glass fiber reinforced thermoplastic resin sheet obtained from the nonwoven fabric-like composite sheet of Examples 1 to 5 was compared with the glass fiber reinforced thermoplastic resin sheet obtained from the nonwoven fabric-like composite sheet of Comparative Example 1. Thus, it can be seen that the thermal expansion coefficient in the thickness direction is reduced by about 30% or more. This is because the short glass fibers oriented in the thickness direction contained in the nonwoven fabric-like composite sheets of Examples 1 to 5 are oriented in the thickness direction even in the glass fiber reinforced thermoplastic resin sheet, and are thermoplastic. This is probably because the thermal expansion in the thickness direction of the matrix resin is suppressed. Furthermore, it turns out that the copper-clad laminated sheet obtained from the nonwoven fabric-like composite sheet of Examples 1-5 has high shape stability in the high temperature environment of 260 degreeC used by normal reflow soldering. On the other hand, the copper-clad laminate sheet obtained from the nonwoven fabric-like composite sheet of Comparative Example 2 had low shape stability under a high temperature environment. This is presumably because the nonwoven fabric-like composite sheet of Comparative Example 2 contained a large amount of short glass fibers and a relatively small content of long glass fibers oriented in the plane direction.

  From the results of the above examples, by using the method for producing a glass fiber nonwoven fabric of the present invention, the long glass fibers are oriented horizontally with respect to the plane direction, and at least a part of the short glass fibers are in the plane direction. It was confirmed that it was possible to produce a glass fiber nonwoven fabric having an angle of 60 to 120 degrees. And the glass fiber reinforced thermoplastic resin sheet, which is a heat-pressed molded body of a composite containing the glass fiber nonwoven fabric and the thermoplastic matrix resin, has a markedly reduced thermal expansion in the thickness direction, and in a high temperature environment. Since the shape stability is high, it was confirmed that it is useful for forming a wiring board, particularly a laminated wiring board.

DESCRIPTION OF SYMBOLS 10 Glass fiber nonwoven fabric 11 Glass long fiber 12 Glass short fiber 20 Thermoplastic matrix resin layer 21 Thermoplastic matrix resin bead 22 Thermoplastic matrix resin fiber 23 Thermoplastic matrix resin 30 Glass fiber reinforced thermoplastic resin sheet

Claims (11)

  A glass fiber nonwoven fabric comprising a glass long fiber having a length of 3 to 25 mm and a glass short fiber having a length of 0.3 to 1 mm in a mass ratio of 50:50 to 90:10, wherein the glass length The fibers are oriented horizontally with respect to the planar direction of the glass fiber nonwoven fabric, and at least a portion of the short glass fibers are inserted into the interior at an angle of 60 to 120 degrees with respect to the planar direction of the glass fiber nonwoven fabric. A glass fiber nonwoven fabric characterized by being made.   The glass fiber nonwoven fabric according to claim 1, wherein 30% or more of the short glass fibers are inserted into the glass fiber nonwoven fabric at an angle of 60 to 120 degrees with respect to a planar direction of the glass fiber nonwoven fabric.   The glass fiber nonwoven fabric according to claim 1 or 2, wherein 80% or more of the long glass fibers are oriented at an angle of ± 30 degrees or less with respect to a planar direction of the glass fiber nonwoven fabric.   It is a wet nonwoven fabric, The glass fiber nonwoven fabric as described in any one of Claims 1-3.   The composite_body | complex containing the glass fiber nonwoven fabric as described in any one of Claims 1-4, and a thermoplastic matrix resin.   The composite according to claim 5, wherein the matrix resin is disposed in a layered manner on at least one surface of the glass fiber nonwoven fabric.   The composite according to claim 5, wherein the matrix resin is arranged in the form of beads or fibers inside the glass fiber nonwoven fabric.   A fiber-reinforced thermoplastic resin sheet, which is a heat-pressed molded body of the composite according to any one of claims 5 to 7.   A metal-clad laminate sheet comprising the fiber-reinforced thermoplastic resin sheet according to claim 8 and a metal foil bonded to at least one surface of the fiber-reinforced thermoplastic resin sheet. An aqueous glass fiber dispersion in which glass long fibers having a length of 3 to 25 mm and short glass fibers having a length of 0.3 to 1 mm are dispersed in water at a mass ratio of 50:50 to 90:10 Preparing a liquid;
And a step of paper-making the glass fiber aqueous dispersion. A glass fiber nonwoven fabric comprising a glass long fiber having a length of 3 to 25 mm and a glass short fiber having a length of 0.3 to 1 mm in a mass ratio of 50:50 to 90:10, wherein the glass length The fibers are oriented horizontally with respect to the planar direction of the glass fiber nonwoven fabric, and at least a portion of the short glass fibers are inserted into the interior at an angle of 60 to 120 degrees with respect to the planar direction of the glass fiber nonwoven fabric. Preparing a composite comprising a non-woven glass fiber and a thermoplastic matrix resin;
A method for producing a fiber-reinforced thermoplastic resin sheet, comprising a step of heat-pressing the composite.

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