TWI695865B - Primer composition, and metal-clad laminate and manufacturing method of the same - Google Patents

Abstract

A primer composition, and a metal-clad laminate and a manufacturing method of the same are provided. The utilization of the primer composition can form a primer layer onto a plastic substrate to enhance an adhesive force between a metal layer and the plastic substrate. The primer composition includes a polyimide resin, an effective content of hardener, and a solvent. A ratio of a dielectric constant （Dk） and a dielectric dissipation factor （Df） of the polyimide resin is ranging from 700 to 1200.

Description

Primer composition, metal laminate and preparation method thereof

The invention relates to a primer composition, a metal laminate and a method for manufacturing the same, in particular to a primer composition suitable for metallization, a metal laminate with a low rate of decline in peel strength and a method for making the same.

With the advancement of technology, the utilization rate of flexible copper clad laminate (FCCL) has gradually increased, and it is widely used in the electronics industry. During the preparation of the flexible copper foil laminate, a metal layer is placed on a plastic substrate. Generally speaking, the surface of the plastic substrate is usually relatively hydrophobic or chemically inert, and it is not easy to combine with metal elements. Therefore, when the plastic substrate is metallized in a wet process, due to the poor adhesion of metal ions to the plastic substrate, pin holes on the surface of the metal layer, or skip plating and plating may occur The problem of peeling makes the production yield of flexible copper foil laminates poor.

In order to overcome the above problems, physical treatment or chemical treatment is used to modify the plastic substrate in the prior art to improve the adhesion of the metal layer. For example, the physical treatment may be plasma treatment or short-wavelength ultraviolet treatment on the plastic substrate to improve the surface properties of the plastic substrate. Chemical treatment is to form functional groups that can initiate reaction or chelate on the plastic substrate by modifying, grafting or blending the plastic substrate, such as hydroxyl, carboxyl, nitrile or polysiloxyalkyl, etc. It is beneficial to provide a metal layer on the plastic substrate. However, the above physical or chemical treatment methods still have limitations on some substrate materials, and cannot simultaneously take into account the electrical characteristics of the flexible copper foil laminate and the peel strength and integrity of the metal layer.

The technical problem to be solved by the present invention is to provide a primer composition, a metal laminate and a method for manufacturing the same in view of the deficiencies of the prior art.

In order to solve the above technical problems, one of the technical solutions adopted by the present invention is to provide a primer composition, which is used on a plastic substrate to form a primer layer, so as to increase the distance between a metal layer and the plastic substrate Adhesion. The primer composition includes: a polyimide resin, an effective amount of hardener and a solvent; the dielectric constant (Dk) and dielectric dissipation factor (Df) of the polyimide resin ) Is 700 to 1200.

In order to solve the above technical problems, another technical solution adopted by the present invention is to provide a metal laminate. The metal laminate includes: a plastic substrate, a primer layer and a metal layer; the primer layer is formed on the plastic substrate, the primer layer is formed by the aforementioned primer composition; the metal layer is formed on the primer layer The primer layer is used to improve the adhesion between the metal layer and the plastic substrate; wherein, the peeling strength decline rate of the metal laminate is less than 15%.

In order to solve the above technical problems, another technical solution adopted by the present invention is to provide a method for manufacturing a metal laminate. The manufacturing method of the metal laminate includes the following steps: providing a plastic substrate; forming a primer layer on the plastic substrate; forming a metal layer on the primer layer, the primer layer is used to improve the metal layer and the plastic substrate Adhesion between the two, and a metal laminate is produced; wherein, the peeling strength decline rate of the metal laminate is less than 15%.

One of the beneficial effects of the present invention is that the primer composition, metal laminate and the manufacturing method thereof provided by the present invention can pass the "primer composition including polyimide resin, hardener and solvent" and "controllable polymer The technical characteristics of “Dk/Df ratio of amide imide resin” can improve the metallization defects of plastic substrates, improve the adhesion of metal laminates, and can be applied to continuous roll coating processes.

In order to further understand the features and technical contents of the present invention, please refer to the following detailed description and drawings of the present invention. However, the drawings provided are for reference and explanation only, and are not intended to limit the present invention.

The following is a specific specific example to illustrate the embodiments of the present invention related to "primer composition, metal laminate and its manufacturing method", those skilled in the art can understand the advantages and effects of the present invention from the content disclosed in this specification . The present invention can be implemented or applied through other different specific embodiments. Various details in this specification can also be based on different viewpoints and applications, and various modifications and changes can be made without departing from the concept of the present invention. In addition, the drawings of the present invention are merely schematic illustrations, and are not drawn according to actual sizes, and are declared in advance. The following embodiments will further describe the related technical content of the present invention in detail, but the disclosed content is not intended to limit the protection scope of the present invention.

It should be understood that although terms such as “first”, “second”, and “third” may be used herein to describe various elements or signals, these elements or signals should not be limited by these terms. These terms are mainly used to distinguish one component from another component, or one signal from another signal. In addition, the term "or" as used herein may include any combination of any one or more of the associated listed items, depending on the actual situation.

The first embodiment of the present invention provides a primer composition for coating on a plastic substrate, which can improve the adhesion between the plastic substrate and the metal layer. In this way, even a plastic substrate with a high surface hydrophobicity or reactive inertness can still form a metal layer on the plastic substrate through a wet process, and the obtained metal laminate has higher peel strength.

The primer composition includes a polyimide resin, a hardener and a solvent, and the solid content of the polyimide resin in the primer composition is 20 wt% to 30 wt%. In actual use, a solvent can be added to dilute the solid content of the polyimide resin in the primer composition to 10wt% to 16wt%, to improve the convenience of coating and to help control the thickness of the coating. However, the present invention is not limited to this. The solid content of the primer composition can be adjusted according to actual use requirements. Preferably, the solid content of the polyimide resin in the primer composition is 10wt% to 35wt%.

The polyimide resin used in the present invention is a soluble resin, and the ratio of the dielectric constant (Dk) to the dielectric loss factor (Df) is 700 to 1200 (or all positive integers between 700 and 1200, for example: 800, 900, 1000 and 1100), hereinafter referred to as Dk/Df ratio. By adjusting the Dk/Df ratio of the polyimide resin, the adhesion of the metal layer to the plastic substrate can be improved, and the problem of missing plating can be avoided. In this embodiment, the dielectric constant of the polyimide resin is 2.0 to 3.5, and the dielectric loss factor is 0.001 to 0.006. In other words, the polyimide resin used in the present invention has good electrical characteristics and can improve the adhesion between the plastic substrate and the metal layer.

Generally speaking, polyimide resin is formed by the polymerization of diamine and dianhydride. In this embodiment, the diamine may be an aliphatic diamine, preferably an aliphatic dimer diamine (dimer diamine). The dianhydride may be bisphenol A dianhydride (BPADA), benzophenone tetracarboxylic dianhydride (BTDA), biphenyltetracarboxylic dianhydride (BPDA), or a combination thereof. However, the invention is not limited to this. Moreover, in the present invention, by adjusting the use molar ratio of diamine and dianhydride to be greater than 1 (that is, the amount of diamine is greater than the amount of dianhydride), the terminal of the molecular chain of the synthesized polyimide resin can be an amine group. It is soluble resin. In addition, in this embodiment, the glass transition temperature of the polyimide resin is 35°C to 50°C. The specific components and detailed characteristics of the polyimide resin will be described later.

The effective addition amount of hardener refers to the hardener required to achieve the desired effect. The so-called expected effect is to cure the polyimide resin. The hardener may be an epoxy compound, an isocyanate compound or a composition thereof. The hardener can help the crosslinking reaction of the polyimide resin to increase the strength, heat resistance and resistance of the primer composition, and facilitate the subsequent metallization process.

In a preferred embodiment, the hardener is an isocyanate compound, and the effective addition amount of the isocyanate hardener can be adjusted according to actual use requirements. Preferably, the content of the isocyanate hardener is polyimide in the primer composition 1wt% to 15wt% of the resin. When the isocyanate compound is selected as the hardener of the polyimide resin, the reaction rate of the polyimide resin and the isocyanate compound is faster, and after a short time drying (drying at 160°C for 2 to 3 minutes), Cures and reaches a certain hardness. If an epoxy compound is used as a hardener, it takes a long time to bake (at 150°C for more than 2 hours) to complete a certain degree of curing.

Isocyanate compounds include but are not limited to: 4,4'-diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), 3-isocyanatomethylene-3,5,5-trimethylcyclohexyl isocyanate ( IPDI), polyphenyl polymethylene polyisocyanate (PAPI), 2-allylphenol isocyanate, 4-methoxyphenol isocyanate, 2,2-bis(4-isocyanatophenol)-1,1 ,1,3,3,3-hexafluoropropane, bisphenol A isocyanate, diallyl bisphenol A isocyanate, 4-phenylphenol isocyanate, 1,1,1-ginseng (4-isocyanatophenyl ) Ethane, 4-cumenylphenol isocyanate, 1,1-bis(4-isocyanatophenyl)ethane, 4,4-bisphenol isocyanate, 2,2-bis(4-isocyanato Phenyl) propane or a combination thereof.

The solvent may be, but not limited to: cyclohexanone, toluene, N-methyl-2-pyrrolidone, dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, N-methylcaprolactam, methyltriethylene glycol dimethyl ether, methyl diglyme, γ-butyrolactone, cyclohexanone, methylcyclohexanone, toluene, xylene, methyl Isobutyl ketone, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, or a combination thereof. When a solvent containing cyclohexanone or toluene is used, it is advantageous to uniformly coat the primer composition on the plastic substrate to form a primer layer with a desired thickness. In a preferred embodiment, the solvent is cyclohexanone.

Please refer to FIG. 1 and FIG. 2 together. FIG. 1 is a schematic side cross-sectional view of the metal laminate of the present invention. FIG. 2 is a flowchart of a method of manufacturing the metal laminate of the present invention. An embodiment of the present invention provides a metal laminate 1 including a plastic substrate 10, a primer layer 20, and a metal layer 30. The primer layer 20 is disposed between the plastic substrate 10 and the metal layer 30. Through the use of the primer layer 20, the metal layer 30 can be attached to the plastic substrate 10, which improves the metalization defects of the original plastic substrate 10, improves the peel strength of the metal laminate 1, and has better heat treatment resistance.

In step S100, a plastic substrate 10 is provided. In this embodiment, the material type of the plastic substrate 10 is not limited. In terms of the improvement effect of the peel strength, the primer composition used in the present invention can significantly improve the material nature of the plastic substrate 10 with high hydrophobicity and low chemical reactivity, so it is advantageous for the metallization of the surface of the plastic substrate 10. In this embodiment, the material of the plastic substrate 10 may be polyimide, liquid crystal polymer or polyester. The thickness of the plastic substrate 10 may be 5 μm to 300 μm, but it is not limited to this, and can be adjusted according to the manufacturing process and finished product requirements.

In step S102, a primer composition is provided on the plastic substrate 10. The method of setting the primer composition may be coating or co-extrusion. Since the plastic substrate 10 can be a flexible substrate, it can also use continuous roll coating to improve production efficiency, such as slot die coating or micro gravure coating technology. It is worth noting that when the isocyanate compound is selected as the hardener, the reaction rate of the polyimide resin and the isocyanate compound is faster, and it is particularly suitable for continuous roll coating.

During continuous roll production, if the plastic substrate 10 is coated on one side with a primer composition, and the primer composition is not cured to a certain degree. At the time of winding, the primer composition may stick to the plastic substrate 10 on the other side. Or, if the plastic substrate 10 is coated on both sides with a primer composition, and the primer composition is not cured to a certain degree. At the time of winding, the primer composition may stick to or even cross-link with the primer composition on the other side of the plastic substrate 10, resulting in the plastic substrate 10 being unable to separate. Therefore, in a preferred embodiment, when produced in a continuous roll form, the primer composition includes at least one isocyanate compound as a hardener.

In step S104, the primer composition is dried and cured to form the primer layer 20 on the plastic substrate 10. Specifically, in the continuous roll coating process, baking and drying are performed at a temperature of 150°C to 170°C for 1 to 5 minutes. Next, the polyimide resin is fully cured at a temperature of 40°C to 60°C for 18 to 22 hours to form the primer layer 20 on the plastic substrate 10.

In the manufacturing method of the metal laminate 1 of the present invention, the provision of the primer layer 20 can improve the defects of the metallization of the plastic substrate 10, avoid the problems of pinholes, missing plating or plating peeling, and without affecting the optical effect Improve appearance. In addition, by adjusting the solid content of the primer composition and using different numbers of wire rods during coating, primer layers 20 of different thicknesses can be formed. The thickness of the primer layer 20 affects the peel strength of the metal laminate 1 and the rate of decline in peel strength after heat treatment. Therefore, the thickness of the primer layer 20 of the present invention is greater than 0.8 microns. When the thickness of the primer layer 20 is greater than 0.8 microns, the rate of decline in peel strength after heat treatment is less than 15%. If the thickness of the primer layer 20 is greater than 1.2 microns, the rate of decay in peel strength after heat treatment may be less than 10%. The detailed experimental parameters and results will be described later. In addition, in order to prevent the thickness of the primer layer 20 from affecting the physical characteristics of the metal laminate 1 and to meet the demand for thinner back-end products on the market, the thickness of the primer layer 20 can be appropriately controlled to be less than 3.0 microns.

In step S106, a metal layer 30 is formed on the primer layer 20 to obtain the metal laminate 1. The method of forming the metal layer 30 may be electroless plating, sputtering, deposition, or electrolytic plating, but not limited thereto. The thickness of the metal layer 30 is not limited, and the preferred thickness is 0.2 μm to 18 μm.

Please refer to FIGS. 2 and 3 together. In other embodiments, the step S106 of setting the metal layer 30 may further include: first setting a seed layer 31 (seed layer) on the primer layer 20 (step S107), and then A plating layer 32 is formed on the seed layer 31 by electroplating, and finally a metal layer 30 is formed (step S108). The method for providing the seed layer 31 may be chemical plating or sputtering, but not limited thereto. The composition of the seed layer 31 and the plating layer 32 may be the same or different. In one embodiment, the seed layer 31 is a nickel layer, and the nickel layer includes 2 wt% to 4 wt% phosphorus. In this way, the arrangement of the seed layer 31 can further improve the peel strength of the metal laminate 1.

Please refer to FIG. 4. In another embodiment, the metal laminate 1 may be a double-sided metallized metal laminate 1. Similar to the manufacturing method of the metal laminate 1 described above, a plastic substrate 10 is first provided (step S100). Primer compositions are respectively provided on two opposite surfaces of the plastic substrate 10 (step S102). The primer composition is dried and cured to form a primer layer 20 on two opposite surfaces of the plastic substrate 10 (step S104). A metal layer 30 is formed on each of the two primer layers 20, and finally, a double-sided metallized metal laminate 1 is formed (step S106).

In order to compare the effects of different polyimide resins, the present invention selects a variety of diamines and dianhydrides to polymerize them to form the polymers of Examples 1 to 3 (E1 to E3) and Comparative Examples 1 to 7 (C1 to C7). Acrylic resin. The characteristics of the polyimide resin formed by polymerization were analyzed. The analyzed characteristics include: dielectric constant (Dk), dielectric loss factor (Df), Dk/Df ratio and glass transition temperature (Tg). The detailed results are listed in Table 1 below.

The primer composition containing the polyimide resin is placed on the plastic substrate 10, and after the primer layer 20 is formed, the effect of metallization is verified. Authentication properties include: the original peel strength (P _0), 288 ° C by immersion tin (solder dipping) peel strength (P _A) after the heat treatment, and the appearance after plating. And according to P ₀ and P _A , define the peel strength decline rate after heat treatment = (1-P _A /P ₀ )×100%, when the peel strength decline rate is less than or equal to 15%, it means that the metal laminate 1 has a good The reliability of the following. The detailed measurement results are listed in Table 1 below.

Table 1: Characteristic analysis of polyimide resins in Examples 1 to 3 (E1 to E3) and Comparative Examples 1 to 7 (C1 to C7). Monomer composition of polyimide resin (molby) Characteristic analysis Metallization verification Dielectric characteristics (1GHz) Tg (°C) Peel strength (kgf/cm) Peel strength decline rate Coating appearance Overall evaluation Diamine Dianhydride Dk Df Dk/Df P ₀ P _A E1 DD BPADA 3.34 0.004 835 47 0.953 0.876 8.1% by ◎ E2 DD BTDA 2.92 0.003 973 38 0.903 0.847 6.2% by ◎ E3 DD BPDA 3.14 0.004 785 41 0.928 0.872 6.0% by ◎ C1 ODA PMDA 3.45 0.013 265 ＞380 0.472 0.391 17.2% by △ C2 0.70ODA 0.30PDA PMDA 3.54 0.012 295 ＞380 0.423 0.317 25.1% by △ C3 0.45ODA 0.55PDA 0.50PMDA 0.50BPDA 3.52 0.013 271 351 0.657 0.526 19.9% by ○ C4 PDA BPDA 3.78 0.012 315 357 0.663 0.563 15.1% by ○ C5 TFMB 0.75BPDA 0.25BPADA 3.36 0.008 420 282 0.532 0.352 33.8% Leak plating ╳ C6 TFMB 6FDA 3.12 0.009 347 274 0.568 0.429 24.5% Leak plating ╳ C7 0.50TFMB 0.50PDA 0.70BPDA 0.30BPADA 3.39 0.005 678 265 0.324 0.175 46.0% Leak plating ╳

The overall evaluation in Table 1 is a comprehensive evaluation of the peel strength decline rate and the appearance of the coating. The "◎" symbol indicates excellent effect, the "○" symbol indicates good effect, and the "△" symbol indicates acceptable effect, "╳" The symbol represents extremely poor effect.

In Table 1, diamines include: dimer diamine (DD), 4,4'-diaminodiphenyl ether (ODA), p-phenylenediamine (PDA) and m-di(trifluoromethyl) p-diamine Amino biphenyl (TFMB). Diacid anhydride includes: pyromellitic dianhydride (PMDA), biphenyltetracarboxylic dianhydride (BPDA), bisphenol A diether dianhydride (BPADA), hexafluorodianhydride (6FDA) and benzophenone tetracarboxylic dianhydride Anhydride (BTDA).

According to the results in Table 1, when a polyimide resin having a Dk/Df ratio of more than 700 is used as the main component of the primer composition, it can have good metallization properties. Not only does the appearance of the coating of the metal layer 30 have complete leak-free plating, but after heat treatment, the decay rate of the peeling strength of the metal laminate 1 is less than 15%, and it has good adhesion, even less than 10%. It can be seen from this that the primer composition of the present invention can improve the metallization defects of the plastic substrate 10 and has good adhesion reliability.

In addition, the present invention uses the polyimide resin of Example 1 as the main component of the primer composition, and forms a primer layer 20 of different thicknesses on a plastic substrate 10 made of polyimide or liquid crystal polymer to produce The metal laminates 1 of Examples 4 to 12 (E4 to E12) and Comparative Examples 8 to 13 (C8 to C13) were obtained. To compare the influence of the thickness of the primer layer 20 on the metallization effect and subsequent reliability, the detailed results are listed in Table 2 below.

Table 2: Characteristic analysis of metal laminates in Examples 4 to 12 (E4 to E12) and Comparative Examples 8 to 13 (C8 to C13). Metal laminate specifications Peel strength (kgf/cm) Peel strength decline rate Coating appearance Overall evaluation Plastic substrate material Thickness of primer layer (μm) P _A P _A E4 Transparent Polyimide 0.84 0.913 0.810 11.3% by ○ E5 Transparent Polyimide 0.92 0.917 0.807 12.0% by ○ E6 Transparent Polyimide 1.08 0.931 0.821 11.8% by ○ E7 Transparent Polyimide 1.36 1.064 1.009 5.2% by ◎ E8 Transparent Polyimide 1.67 1.045 0.994 4.9% by ◎ E9 Transparent Polyimide 1.84 1.094 1.034 5.5% by ◎ E10 Transparent Polyimide 2.15 1.135 1.076 5.2% by ◎ E11 Transparent Polyimide 2.96 1.218 1.131 7.1% by ◎ C8 Transparent Polyimide - 0.442 0.326 26.2% Lots of missing plating ╳ C9 Transparent Polyimide 0.40 0.639 0.183 71.4% by ╳ C10 Transparent Polyimide 0.47 0.756 0.235 68.9% by ╳ C11 Transparent Polyimide 0.63 0.838 0.468 44.2% by △ C12 Transparent Polyimide 0.76 0.891 0.681 23.6% by ╳ E12 Liquid crystal polymer 1.79 0.615 0.601 2.3% by ◎ C13 Liquid crystal polymer - 0.263 0.206 21.7% Missing plating, pinhole ╳

The overall evaluation in Table 2 is a comprehensive evaluation of the peel strength decline rate and the appearance of the coating. The "◎" symbol indicates excellent effect, "○" symbol indicates good effect, "△" symbol indicates acceptable effect, "╳" The symbol represents extremely poor effect.

According to the results in Table 2, it can be found that, as long as the primer layer 20 is provided, whether the material of the plastic substrate 10 is polyimide or liquid crystal polymer, it can have a good metallization effect. In Comparative Examples 8 and 13, since the primer layer 20 is not provided, not only the peel strength is low, but also after the metallization, pin holes are generated and there is a problem of missing plating.

Moreover, due to the arrangement of the primer layer 20, the reliability of the metal laminate 1 can be improved. Even after the tin dip heat treatment, the decline rate of the peel strength can be maintained below 15%. In Table II, the peel strength decay rate _{= (1-P A / P} 0) × 100%, where, P ₀ is the peel strength before the heat treatment, P _A is the peel strength after the heat treatment. The smaller the decay rate of peel strength means that the metal laminate 1 has better temperature resistance, and the metal layer 30 will not peel off from the metal laminate 1 due to heat treatment.

Specifically, when the thickness of the primer layer 20 is greater than 0.8 micrometers, the peel strength of the metal laminate 1 can be greater than 0.900kgf/cm, even after the tin-immersion treatment at 288°C, the peel strength can still be maintained at 0.800kgf/ Above cm, and the peel strength decline rate is less than 15%. Furthermore, when the thickness of the primer layer 20 is greater than 1.2 μm, the peel strength of the metal laminate 1 can be maintained at 1.030 kgf/cm or more. Even after the tin-immersion treatment at 288°C, the peel strength can still be maintained at Above 0.990kgf/cm, that is, the peeling strength decline rate is less than 10%.

[Beneficial effect of embodiment]

One of the beneficial effects of the present invention is that the primer composition, metal laminate and the manufacturing method thereof provided by the present invention can pass the "primer composition including polyimide resin, hardener and solvent" and "controllable polymer The technical characteristics of “Dk/Df ratio of amide imide resin” can improve the metallization defects of plastic substrates, improve the adhesion of metal laminates, and can be applied to continuous roll coating processes.

Further, through the technical feature of “adjusting the solid content of the polyimide resin”, the primer composition is suitable for the coating process, and the primer layer 20 of various thicknesses can be formed according to requirements. The metal laminate 1 has a better peel strength, and even after a tin immersion treatment at 288°C, it still has a lower peel strength decline rate.

Further, through the technical feature of “selecting a specific solvent”, the primer composition can be uniformly dispersed and not easily adhered, which is advantageous for coating on the plastic substrate 10. In order to form the primer layer 20 with a uniform thickness.

Furthermore, through the technical feature of “adjusting the thickness of the primer layer 20 ”, the primer layer 20 can effectively improve the effect of the metallization of the plastic substrate 10 and further improve the subsequent reliability of the metal laminate 1.

The content disclosed above is only a preferred and feasible embodiment of the present invention, and therefore does not limit the scope of the patent application of the present invention, so any equivalent technical changes made by using the description and drawings of the present invention are included in the application of the present invention. Within the scope of the patent.

1: metal laminate

10: Plastic substrate

20: primer layer

30: metal layer

31: Seed layer

32: plating layer

S100, S102, S104, S106-S108: steps

FIG. 1 is a schematic side sectional view of a metal laminate in one embodiment of the present invention.

2 is a flowchart of a method for manufacturing a metal laminate in one embodiment of the present invention.

3 is a schematic side cross-sectional view of a metal laminate in still another embodiment of the present invention.

4 is a schematic side cross-sectional view of a metal laminate in another embodiment of the invention.

1: metal laminate

10: Plastic substrate

20: primer layer

30: metal layer

Claims (11)

A primer composition is used on a plastic substrate to form a primer layer to improve the adhesion between a metal layer and the plastic substrate. The primer composition includes: a polyimide resin ; The ratio of the dielectric constant to the dielectric loss factor of the polyimide resin at 1 GHz measurement conditions is 700 to 1200; an effective amount of hardener; and a solvent. The primer composition as described in item 1 of the patent application range, wherein the solid content of the primer composition is 10 wt% to 16 wt%. The primer composition as described in item 1 of the patent application range, wherein the polyimide resin is a soluble resin. The primer composition as described in item 1 of the patent application range, wherein the hardener includes at least one isocyanate compound. A metal laminate includes: a plastic substrate; a primer layer formed on the plastic substrate; wherein the primer layer is at least formed of a polyimide resin, the polyimide The ratio of the dielectric constant of the amine resin under the measurement condition of 1 GHz to the dielectric loss factor is 700 to 1200; and a metal layer formed on the primer layer, the primer layer is used to improve the metal layer Adhesion with the plastic substrate; wherein, the peeling strength decline rate of the metal laminate is less than 15%. The metal laminate as described in item 5 of the patent application range, wherein the material of the plastic substrate is polyimide, liquid crystal polymer or polyester. The metal laminate according to item 5 of the patent application range, wherein the thickness of the primer layer is 0.8 μm to 3.0 μm. The metal laminate according to item 5 of the patent application range, wherein the thickness of the metal layer is 0.2 μm to 18 μm. A method for manufacturing a metal laminate includes the following steps: providing a plastic substrate; forming a primer layer on the plastic substrate; wherein, the primer layer is at least formed of a polyimide resin. The ratio of the dielectric constant of the polyimide resin under the measurement condition of 1 GHz to the dielectric loss factor is 700 to 1200; and forming a metal layer on the primer layer, the primer layer is used to improve the The adhesive force between the metal layer and the plastic substrate, and the metal laminate board is prepared; wherein, the peeling strength decline rate of the metal laminate board is less than 15%. The method for manufacturing a metal laminate according to item 9 of the patent application scope, wherein the plastic substrate is a flexible substrate, and the primer composition is applied on the plastic substrate in a roll shape. The method for manufacturing a metal laminate according to item 9 of the patent application scope, wherein the metal layer is formed by chemical plating, sputtering, evaporation or electrolytic plating.

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