TW201525030A - Process to fabricate a fiber-resin-composite, particularly related to manufacturing circuit board - Google Patents

Abstract

A process to fabricate a fiber-resin-composite comprises providing a plurality of fibers (5), immersing the fibers by using a flowable resin (7), and hardening the resin (7), wherein the pre-immersed fibers (5) are coarsened to make the coarseness of the fibers (5) increased. In addition, the present invention is related to a method of manufacturing a circuit board, which includes: manufacturing a fiber-resin composite (3), forming a conductive structure (9) on at least a surface of the fiber-resin composite (3). Additionally, the present invention is related to a fiber-resin composite, which is composed of the fiber (5) encapsulated by the curable resin (7), and a conductive structure (9) on at least a surface of the fiber-resin composite (3), wherein the fiber (5) is coarsened so that the arithmetic mean coarseness value Ra on the surface of the fiber (5) is at least 0.1 micrometer. Because of the better joint between the fiber (5) and the encapsulated resin (7), the circuit board can have higher mechanical stability and realize the mechanical bearing function.

Description

Fabrication of fiber-resin composites, particularly methods of making circuit boards

The present invention relates to a method of making a fiber-resin composite, particularly a method of making a circuit board and related circuitry.

Fiber-resin composites (some of which are also referred to as fiber-resin composites) are used for very different technical applications, they can be manufactured relatively simply at low cost, and are mostly capable of withstanding high mechanical, chemical and electrical loads.

To make fiber composites, fibers, such as glass fibers or carbon fibers, are typically provided and then impregnated into a flowable resin. This resin flows through the fibers. Depending on the application, the fibers may, for example, be woven into a mat or a non-woven Gelege and then harden the resin surrounding the fibers.

The fiber-resin composite may be provided in the form of a substrate having mechanical stability and chemical resistance (and mostly non-conductive) depending on the type of resin used in the fiber type and the geometric arrangement of the fibers in the surrounding resin.

Such fiber-resin composites are particularly suitable for the manufacture of circuit boards. A typical circuit board consists of an electrically insulating carrier material or a bottom material which is plated with one or several electrically conductive constructions. Lift For example, the conductive structure can be designed as a copper layer with a typical layer thickness of 10 to 300 microns, wherein in general use, a typical layer thickness is in the range of 20 to 50 microns, for example 35 microns, when higher current is used, the layer The thickness of the carrier is between 50 and 300 microns, for example between 70 and 140 microns. The carrier or the bottom material used is often Pertinax, which contains phenol resin. For the applications that are often required today, most of them are impregnated with epoxy resin. Glass fiber mesh, they are also known as material name FR4 or FR5 (FR = flame retardant, flame retardant).

Today, in addition to the original purpose of the conductive flow - the circuit board also meets more and more functions. For example, it is desirable to be able to utilize the board to position or secure or protect the components from damage by the media.

For example, a circuit board is used in a construction vehicle to construct a linkage control device, wherein the circuit board can form part of the housing of the electronic circuit of the linkage control device, which is to be housed inside the vehicle gearbox and thus must be sealed to prevent The surrounding gearbox oil or other media such as air, chips, moisture, etc., and can withstand the main mechanical load.

Fiber resin composites can be produced in an advantageous manner using the embodiments of the present invention (for example, for use as a carrier substrate or a base substrate to manufacture a circuit board, and having high mechanical load). In particular, the fiber resin composite can be manufactured by the method shown here, and the circuit board manufactured based thereon can withstand higher mechanical load than the conventional circuit board.

According to a first aspect of the invention, a method of making a fiber resin composite is provided. The method comprises providing a plurality of fibers, impregnating the fibers with a flowable resin and hardening the resin, characterized by roughening the fibers to increase the fiber roughness prior to impregnation.

According to another aspect of the present invention, the aforementioned method for producing a fiber-resin composite material can be used. A circuit board is manufactured in which a conductive structure is formed on a surface of a fiber resin composite material to be manufactured.

According to a third feature of the present invention, a circuit board manufactured by the above method is provided, wherein the circuit board has a fiber resin composite material composed of fibers surrounded by a hardened resin, and at least one surface thereof has a conductive structure, and the circuit board is characterized by : The fibers are roughened such that the fiber surface has an arithmetic mean roughness of at least Ra > 0.1 microns, possibly Ra > 0.2 microns or Ra > 0.4 microns.

The concept of an embodiment of the present invention can also be understood from the following description.

As mentioned above, in many applications of circuit boards today, in addition to their main purpose, the current is passed from the power source to a consumer and carries electrical components, and is also used for mechanical functions or protection of components. The media is damaged. In principle, the fiber-resin composite is used. When the circuit board of the carrier substrate is suitable for withstanding the main force, the fiber-reinforced resin material can withstand a large tensile force and pressure. However, it has been observed that when the board is subjected to high or improperly applied forces, the resin surrounding the fibers will be stripped from the fibers and will be destroyed in the worst case, especially when the board is stressed perpendicular to the plane of its board. At this time, the resin surrounding the fibers (especially the glass fibers and adhered thereto) is peeled off and cracked from the circuit board, where the resin portion is cracked from the circuit board and the glass fibers are exposed, and the mechanical function and the sealing function are not reliable. Achieved, and the components are damaged.

In order to increase the resistance to forces acting perpendicular to the plane of the board (which is sometimes referred to as "peeling force"), various measures can be taken. For example, a resin for a fiber resin composite material can be optimized, for example, some components (for example, in an additive manner) can be mixed with a resin to change its mechanical strength, elasticity, and/or adhesion so that it is The mechanical properties of the fiber-resin composite material thus produced are optimized, and an appropriate additive may be added to improve the adhesion between the resin and the fiber.

According to an embodiment of the present invention, the holding action between the resin and the fiber (which is surrounded by the resin) is similarly improved, and thus the fiber resin composite material is resistant to mechanical stress, which can be achieved by using the resin in the following manner. The surface of the surface is changed according to the standard before impregnation, especially the fiber is roughened according to the standard before impregnation.

The term "roughening" as used herein means that the surface of the fiber is machined such that the morphological change is adjusted to level 3 and/or level 4. Here, the roughness of the surface can be measured according to the German industrial standard DIN 4760, where the morphological change of 3 corresponds to the roughness of the shape of the fine mark, and the morphological change of 4 is equivalent to the generation of the groove (Riefen), scaly roughness (Schuppen) And / or Kuppen.

Affected by the manufacturing conditions, as is typical in the case of fiber processing in fiber-resin composites, the fibers have a smoother shell surface (cylindrical surface). For example, in a fiber-resin composite (in which the glass fiber layer is laminated to a resin matrix), the glass fiber has a very smooth surface. Here, in order to manufacture a glass fiber, a fine line is taken out from the glass melt, and since the drawn line is still liquid at least short before the glass melt solidifies, the outer surface of the glass fiber is smooth. Typically, the arithmetic mean roughness Ra of the surface of the glass fiber after the drawing process is < 0.1 μm.

Although such smooth fibers are well processed either individually or in bundles and, for example, woven or gathered with a web, we have observed that the surface of the glass fibers and the surrounding are probably due to the smooth surface of the glass fibers. The problem of adhesion between resin mother materials. Since the adhesion is limited, especially when a high mechanical load acts perpendicularly to the surface of the slab-like fiber-resin composite material and thus when the fiber-resin composite is bent, the interfacial resin is caused to cause partial delamination between the fibers and the surrounding resin. .

Therefore, according to the present invention, the most smooth surface fiber is impregnated into a liquid tree. The grease is processed before further processing to significantly increase the roughness of the surface of the fiber envelope.

The fiber should be roughened so that the arithmetic mean roughness Ra of the fiber surface is adjusted to at least 0.1 micrometer. With the roughening of the fiber surface, the contact area between the fiber and the surrounding resin can be increased on the one hand, and thus the resin is in the fiber. The adhesion on the top is preferred, and the roughening also allows the resin to no longer adhere to a smooth surface, but is embedded in a portion of the surface of the fiber that is obliquely-curved or even has an undercut. Therefore, a shape fit can be caused between the hardened resin and the fibers of the layer. Therefore, the bond between the resin and the fibers of the layer can be greatly improved.

In accordance with an embodiment of the invention, the fibers are woven and/or woven into a web prior to the roughening of the fibers. In other words, the fibers can be further processed into a web in an original state (in other words, in a state where they have a smoother surface after being manufactured straight), and can be simply bundled and then woven and/or woven into one when the outer surface of the fiber is smooth. Stabilizing the layered material, after the fibers are further processed into a web, the fibers in the individual fibers or webs are processed to roughen the surface of the fibers.

For example, the fibers can be roughened chemically. For this purpose, for example, the fibers may be impregnated with an etching solution. For example, the fibers may be passed through an etching bath to roughen the glass fibers. For example, the glass fibers may be roughened to form formic acid or sulfuric acid. The etch solution.

If this is not the case, the fiber can be mechanically roughened (or in addition to this). For example, the fibers can be sandblasted or machined in a moving stone trough.

If this is not the case (or in addition to this method, it is also possible to additionally) the fiber is roughened by illumination. For example, the fiber can be locally irradiated with a laser, so that the surface of the fiber is locally melted for a short time because it is subsequently solidified. When it forms an unevenness in a rough form.

As mentioned above, the fibers can in principle be composed of different materials/and in different geometrical properties. When used as an application circuit board, for example, fiber glass fibers may be in the manner provided herein, glass fibers constituted by silicon oxide (SiO _x), and is therefore electrically insulating. Glass fiber can withstand strong tensile forces. In addition, the elastic modulus of glass fibers is very favorable, so they can be easily processed, especially into fiber webs. Glass fibers can be of different diameters depending on the type of manufacture. Typical diameters range from 1 to 100. In the micrometer range, glass fibers can be in the form of short fibers or long fibers. In principle, glass fibers are processed in fibers-resin composites from fibers composed of other different materials, such as carbon fibers, ramylamine (Aramid) fibers. , Kelvar fiber, a variety of different polymer fibers.

The resin used for the fiber-resin mixture can be processed first in a flowing state and then hardenable, and in particular, thermosetting plastic can be used. When the resin epoxy resin is used for the production of the fiber-resin composite material, it is particularly advantageous, for example, without using this method. Polyester resin can also be used.

In order to prepare a circuit meter from the above fiber-resin composite material, one or a plurality of conductive structures may be formed on the surface thereof, and the conductive structures may form a conductive line through which current can pass and can be utilized, for example. The electrical components are interconnected to be electrically conductive, and in forming such a conductive construction, substantially all of the techniques used in the manufacture of conventional circuit boards can be used.

It is pointed out here that the features and advantages of the embodiments of the present invention are partially explained in conjunction with the method for manufacturing a fiber-resin composite material, on the one hand, in conjunction with the description of the method for manufacturing a circuit board, and in part with the description of the relevant manufacturing circuit board, It is to be understood that the various features described above may be modified, substituted or combined in various ways to achieve embodiments of the invention.

The embodiments of the present invention are described below in conjunction with the drawings, and the description and drawings are not intended to limit the scope of the invention.

(1)‧‧‧ boards

(3)‧‧‧Fiber-resin composites

(5) ‧‧‧Fiber

(7)‧‧‧Resin

(9) ‧‧‧Electrical structure

1 is a perspective view of a circuit board having a fiber-resin composite material according to an embodiment of the present invention; and FIG. 2 is a fiber-resin composite having glass fibers woven into a fiber web according to an embodiment of the present invention. Figure 3 is a cross-sectional view of a roughened fiber for a fiber-resin composite according to an embodiment of the present invention.

These figures are only schematic and not accurate to the correct scale. The same figure numbers in the figures indicate the same or the same function.

1 shows an embodiment of a circuit board, also referred to as a brush circuit board (PCB), which can be used to construct a circuit. In the illustrated example, the circuit board (1) has a substrate, consisting of The fiber-resin composite material (3) is composed of a conductive structure (9) on both sides thereof, and an example of the conductive structure (9) is a copper layer having a layer thickness of 5 to 50 μm.

The fiber-resin composite (3) is mainly composed of a fiber (5) and a resin (7) surrounding the fiber. In the illustrated embodiment, the fiber-resin composite (3) is formed as a glass reinforcing resin (GFRP) in which glass fibers are embedded in a matrix composed of a thermosetting resin, as shown in the upper view of FIG. 2, and the glass fibers are composed of fibers. The bundles (13), and the bundles of fibers (13) are woven together to form a web (1).

In order to manufacture a glass fiber resin composite, a plurality of fibers (5) are first prepared, wherein individual fibers (5) can be bundled and then woven, or woven into a layer, and then the fiber (5) is treated with a flowable resin (7). (for example, epoxy resin) impregnation. Here the resin (7) invades between adjacent fibers (5) or An intermediate space between adjacent fiber bundles (13). Here, the resin (7) wets the surface of the fiber (5), and then the resin is hardened, for example, by adding a hardener or adding energy (for example, in the form of heat or ultraviolet rays). The previously flowable resin (7) then forms a solid parent in the hardened state, in which the fibers are embedded and the matrix is mechanically stabilized by the glass fibers (5).

In order to improve the mechanical joining between the glass fiber (5) and the surrounding resin (7), the fiber (5) is preferably subjected to the surface of the fiber (5) before being impregnated with the flowable resin (7) before being processed into a fiber web (1). Get rough.

As shown in the schematic diagram of Fig. 3, the surface of the glass fiber (5) is subjected to a microscopic structure because the surface is roughened to cause a majority of grooves, scratches, scaly roughness and the surface which is initially smooth after the fiber is manufactured. / or bulges (which are also referred to as the morphological variation of the shell surface of the original fiber which is originally smooth and smooth, grade 3 or 4), so the mechanical joint between the fiber (5) and the surrounding resin (7) is significantly improved.

For example, the fibers (5) may be roughened chemically, mechanically, and/or by light irradiation, and the roughening operation may have an arithmetic mean roughness Ra greater than 0.1 micron.

Here, the mathematical mean roughness Ra can be the roughness within the individual measurement distances. The arithmetic mean of the vertical axis value z, so it is the average deviation of this contour from a midline (15). Here, the individual measurement distances are sized to achieve a statistical arithmetic mean, where the arithmetic mean Ra can be calculated as follows >

The fiber-resin composite material (3) thus formed with the roughened fibers can be particularly used for manufacturing a circuit board (1) to be mechanically functional, in which the properties of the circuit board are not favored by the fiber surface. The impact of the change.

(1)‧‧‧ boards

(3)‧‧‧Fiber-resin composites

(5) ‧‧‧Fiber

(7)‧‧‧Resin

(9) ‧‧‧Electrical structure

Claims (10)

A method of making a fiber-resin composite comprising providing a plurality of fibers (5) impregnated with a flowable resin (7) to harden the resin (7), characterized by: The fiber (5) is roughened to increase the roughness of the fiber (5). The method of claim 1, wherein the fiber (5) is roughened such that the arithmetic mean roughness Ra of the surface of the fiber (5) is adjusted to at least 0.1 μm. The method of claim 1 or 2, wherein the fibers (5) are woven and/or woven into a web (11) before being roughened. The method of claim 1 or 2, wherein the fiber (5) is chemically roughened. The method of claim 1 or 2, wherein the fiber (5) is mechanically roughened. The method of claim 1 or 2, wherein the fiber (5) is roughened by light irradiation. The method of claim 1 or 2, wherein the fiber (5) is a glass fiber and/or the resin (7) is a thermosetting plastic, in particular an epoxy resin. A method of manufacturing a circuit board comprising manufacturing a fiber-resin composite material (3), and forming a conductive structure (9) on at least one surface of the fiber-resin composite material (3). A circuit board (1) comprising a fiber-resin composite material (3) composed of fibers (5) surrounded by a hardenable resin (7), and at least one surface of the fiber-resin composite material (3) There is a conductive structure (9) characterized in that the fiber (5) is roughened such that the surface of the fiber (5) has an arithmetic mean roughness Ra of at least 0.1 μm. The circuit board of claim 9, wherein the fiber (5) is a glass fiber and/or the resin is a thermosetting plastic, in particular an epoxy resin.