Method for preparing curable cyclic olefin copolymer and method for preparing resin-coated copper comprising curable cyclic olefin copolymer

Abstract

According to the present disclosure, a method for preparing a curable cyclic olefin copolymer (COC) is provided, the method comprising the steps of: a) introducing maleic anhydride to a COC to produce a maleic anhydride modified cyclic olefin copolymer; and b) polymerizing the maleic anhydride of the maleic anhydride modified cyclic olefin copolymer with a monomer having a curable functional group to produce a curable cyclic olefin copolymer. According to the method, the heat resistance and mechanical properties of a cyclic olefin copolymer-based insulating layer can be improved without intervention of polyimide.

Description

Method for producing a curable cyclic olefin copolymer and method for producing a resin-coated copper comprising the curable cyclic olefin copolymer

[0001] The present disclosure relates to a method for preparing a curable cyclic olefin copolymer (COC) and a method for preparing resin coated copper (RCC) comprising the curable cyclic olefin copolymer.

[0002] Conventional RCCs consist of a copper film and an insulating layer based on a modified epoxy. However, modified epoxy has chemical structures with dielectric properties unsuitable for high-frequency bands, such as secondary alcohols generated during the epoxy curing process. This limits its application to RCCs for high-frequency bands above 10 GHz.

[0003] Accordingly, research is being conducted to use cyclic olefin copolymers, which have lower dielectric loss characteristics than modified epoxy and are more suitable for use in high-frequency bands, as an insulating layer of RCC. However, cyclic olefin copolymers require additional modification for use as an RCC insulating layer in high-frequency bands due to limitations in thermal and mechanical properties.

[0004] The present disclosure aims to provide a method for preparing a curable cyclic olefin copolymer having dielectric properties suitable for use in a high frequency band, and a method for preparing a resin-coated copper comprising the curable cyclic olefin copolymer.

[0005] According to a first aspect of the present disclosure, a method for preparing a curable cyclic olefin copolymer (COC) is provided, the method comprising the steps of: a) introducing maleic anhydride into COC to produce a maleic anhydride-modified cyclic olefin copolymer; and b) polymerizing a monomer having a curable functional group onto the maleic anhydride of the maleic anhydride-modified cyclic olefin copolymer to produce the curable cyclic olefin copolymer.

[0006] In one embodiment, step a) may be performed in the presence of a peroxide.

[0007] In one embodiment, the peroxide may comprise benzoyl peroxide or dicumyl peroxide.

[0008] In one embodiment, step a) may be performed at a temperature of 50 to 180° C. for 6 to 24 hours.

[0009] In one embodiment, step a) can be performed using a microwave.

[0010] In one embodiment, the method may further comprise a precipitation step for removing unreacted reagents after step a) and before step b).

[0011] In one embodiment, the monomer having a curable functional group of step b) may comprise a hydroxyl group or an amine group.

[0012] According to one embodiment, step b) can be performed at a temperature of 20 to 50 °C.

[0013] According to one embodiment, the method may further comprise a precipitation step after step b) to remove monomers having unreacted curable functional groups.

[0014] According to a second aspect of the present disclosure, a curable cyclic olefin copolymer is provided, wherein the curable cyclic olefin copolymer comprises a maleic anhydride modified cyclic olefin copolymer; and a monomer having a curable functional group.

[0015] According to a third aspect of the present disclosure, a method for producing resin coated copper (RCC) is provided, the method comprising the steps of: 1) preparing a solution comprising a curable cyclic olefin copolymer produced by the above-described production method; and 2) casting the solution comprising the curable cyclic olefin copolymer onto a copper film.

[0016] According to one embodiment, step 1) may include adding 1 to 80 wt% of SiO2 to a solution comprising the curable cyclic olefin copolymer.

[0017] According to the present disclosure, a curable cyclic olefin copolymer having dielectric properties suitable for use in a high-frequency band can be prepared.

[0018] FIG. 1 is a schematic diagram schematically illustrating a process for producing a curable cyclic olefin copolymer according to one embodiment.

[0019] FIG. 2 is a schematic diagram showing the appearance of a maleic anhydride modified cyclic olefin copolymer solution according to one embodiment.

[0020] FIG. 3 is a schematic diagram showing crosslinking between curable cyclic olefin copolymers according to one embodiment.

[0021] The purposes, advantages, and features of the present disclosure will become more apparent from the following detailed description and preferred embodiments, which are illustrated in the accompanying drawings, but are not necessarily limited thereto. Furthermore, in describing the present disclosure, detailed descriptions of related known technologies will be omitted if they are deemed to unnecessarily obscure the gist of the present disclosure.

[0022] According to a first aspect of the present disclosure, a method for preparing a curable cyclic olefin copolymer (COC) is provided, the method comprising the steps of: a) introducing maleic anhydride into COC to produce a maleic anhydride-modified cyclic olefin copolymer. Referring to FIG. 1, the COC comprises an alkane having a bicyclic shape in one of its main chains. In step a), maleic anhydride having a structure of the following chemical formula 1 is polymerized onto the COC in such a manner that one of the carbon-carbon double bonds is broken, thereby forming a bond with the COC. Thereby, a maleic anhydride-modified cyclic olefin copolymer is produced, in which the maleic anhydride acts as a functional moiety. Step a) may be performed in an organic solvent such as toluene or chlorobenzene.

[0023]

[0024] (Chemical formula 1)

[0025] Conventional maleic anhydride-modified cyclic olefin copolymers are produced by reacting maleic anhydride with an amine group of PAA (polyamic acid, a precursor of polyimide) and polymerizing it with COC, so that there is intervention of polyimide in the manufacturing process, whereas in step a) of the present disclosure, the maleic anhydride-modified cyclic olefin copolymer is produced without the intervention of polyimide. Polyimide has a higher property of absorbing moisture than COC, and if the insulating layer of RCC used in a high-frequency band absorbs moisture, the dielectric properties in the high-frequency range may deteriorate. However, since polyimide is not involved in the polymerization process of step a) of the present disclosure, the deterioration of the dielectric properties of the produced copolymer in the high-frequency range can be prevented.

[0026] In one embodiment, step a) may be performed in the presence of a peroxide. The peroxide increases the reactivity of maleic anhydride, thereby facilitating the polymerization reaction between maleic anhydride and COC. Specifically, the peroxide cleaves one of the carbon-carbon double bonds of maleic anhydride, resulting in the formation of a radical. This radical is unstable and highly reactive, facilitating the bonding reaction with COC.

[0027] In one embodiment, the peroxide may include benzoyl peroxide or dicumyl peroxide. Benzoyl peroxide and dicumyl peroxide may have price advantages over other peroxides.

[0028] In one embodiment, step a) may be performed at a temperature of 50 to 180°C for 6 to 24 hours. When COC, maleic anhydride, and peroxide are dissolved in a solvent and then maleic anhydride is polymerized onto COC, the polymerization reaction may be performed more easily. Therefore, it is advantageous to perform the polymerization reaction at a high temperature to dissolve the reagents in the solvent. When step a) is performed at a temperature below 50°C, COC, which has low solubility in the solvent, may not be dissolved to the extent required for the polymerization reaction, thereby reducing the yield of the maleic anhydride-modified cyclic olefin copolymer. In addition, when step a) is performed at a temperature exceeding 180°C, side reactions of highly reactive maleic anhydride radicals may be promoted, thereby forming compounds having undesirable chemical structures. Specifically, step a) may be performed at a temperature of 70 to 120°C, more specifically, 80 to 100°C. The reaction of step a) is carried out at the above temperature for 6 to 24 hours, thereby obtaining a maleic anhydride-modified cyclic olefin copolymer in high yield. The solution containing the maleic anhydride-modified cyclic olefin copolymer produced by step a) is as shown in FIG. 2, and referring to FIG. 2, the maleic anhydride-modified cyclic olefin copolymer is observed in the form of fibers.

[0029] In one embodiment, step a) may be performed using a microwave. When using a microwave as a reactor, the microwave reactor itself automatically sets the optimal reaction temperature by considering the boiling point of the solvent and the pressure within the reactor during the polymerization reaction. Therefore, performing step a) using a microwave has the advantage of reducing the reaction time and maximizing the reaction yield through reaction temperature optimization.

[0030] In one embodiment, the method may further include a precipitation step for removing unreacted reagents after step a) and before step b). By allowing the solution shown in FIG. 2 to settle, a fibrous maleic anhydride-modified cyclic olefin copolymer is precipitated to the bottom of the vessel, and the supernatant is removed, thereby removing unreacted reagents and obtaining a pure maleic anhydride-modified cyclic olefin copolymer.

[0031] The method comprises the step b) of polymerizing a monomer having a curable functional group to the maleic anhydride of a maleic anhydride-modified cyclic olefin copolymer to produce a curable cyclic olefin copolymer. The monomer having a curable functional group can impart heat resistance and mechanical properties to the copolymer, thereby enabling film formation. Referring to FIG. 1, in step b), the monomer having a curable functional group is grafted onto the maleic anhydride position of the maleic anhydride-modified cyclic olefin copolymer. As an example, the monomer having a curable functional group can be polymerized onto the maleic anhydride position of the maleic anhydride-modified cyclic olefin copolymer by grafting from. A curable cyclic olefin copolymer is produced by step b), the schematic chemical structure of which is as shown in FIG. 1, Modified-COC. Step b) can be performed in an organic solvent such as toluene or chlorobenzene.

[0032] In one embodiment, the monomer having a curable functional group of step b) may include a hydroxyl group or an amine group. The hydroxyl group and the amine group can form hydrogen bonds, which can be included in the side chain of the curable cyclic olefin copolymer, thereby promoting crosslinking between each copolymer in subsequent applications such as resin-coated copper including the copolymer. The crosslinking between the copolymers can impart a higher glass transition temperature (Tg) and mechanical properties to the resin-coated copper. As an example, the monomer having a curable functional group of step b) may include 2-Hydroxyethyl acrylate.

[0033] In one embodiment, step b) may be performed at a temperature of 20 to 50° C. If step b) is performed at a temperature of less than 20° C., the polymerization reaction between the monomer having a curable functional group and the maleic anhydride-modified cyclic olefin copolymer may not proceed smoothly, and if step b) is performed at a temperature of more than 50° C., radicals may be generated by trace amounts of peroxide that may be present in the maleic anhydride-modified cyclic olefin copolymer, thereby initiating an undesirable side reaction. Specifically, step b) may be performed at a temperature of 25 to 40° C., more specifically, at a temperature of 30 to 40° C.

[0034] In one embodiment, the method may further include a precipitation step for removing a monomer having an unreacted curable functional group after step b). After step b), a solution containing a solid curable cyclic olefin copolymer and a monomer having an unreacted curable functional group is allowed to settle, so that the solid curable cyclic olefin copolymer precipitates to the bottom of the vessel, and the supernatant is removed, thereby excluding unreacted reagents and obtaining a pure curable cyclic olefin copolymer.

[0035] According to a second aspect of the present disclosure, a curable cyclic olefin copolymer is provided, wherein the curable cyclic olefin copolymer comprises a maleic anhydride-modified cyclic olefin copolymer; and a monomer having a curable functional group. The curable cyclic olefin copolymer comprises a monomer having COC as a main chain, maleic anhydride bonded thereto as a functional moiety, and having a curable functional group grafted from maleic anhydride, such as Modified-COC in FIG. 1. The components and preparation method of the curable cyclic olefin copolymer may be the same as those mentioned in the first aspect of the present disclosure.

[0036] According to a third aspect of the present disclosure, a method for producing resin coated copper (RCC) is provided, the method comprising the steps of: 1) preparing a solution comprising a curable cyclic olefin copolymer produced by the method of claim 1; and 2) casting the solution comprising the curable cyclic olefin copolymer onto a copper film.

[0037] In step 1), a solution is prepared by dissolving a curable cyclic olefin copolymer in a solvent through a manufacturing method according to the first aspect of the present disclosure. Specifically, the solution is prepared by dissolving the above-described curable cyclic olefin copolymer, a peroxide, and an azo-based initiator (e.g., dicumyl peroxide, benzoyl peroxide, AIBN (Azobisisobutyronitrile)) in a high-boiling-point solvent. Here, the peroxide and the azo-based initiator correspond to additives for initiating crosslinking between the curable cyclic olefin copolymers in the subsequent step 2).

[0038] In one embodiment, step 1) may include adding 1 to 80 wt% of SiO2 to a solution containing a curable cyclic olefin copolymer. By adding SiO2 to the solution, the heat resistance and mechanical properties of the RCC produced therefrom may be significantly improved. When the amount of SiO2 added is less than 1 wt%, the effect of improving the heat resistance and mechanical properties of the RCC may be minimal, and when the amount of SiO2 added exceeds 80 wt%, the RCC may be excessively cured and have brittle properties, thereby deteriorating the mechanical properties. In one embodiment, the amount of SiO2 added to the solution containing the curable cyclic olefin copolymer may be specifically 5 to 50 wt%, and more specifically 10 to 30 wt%.

[0039] In step 2), the solution is cast onto a pre-prepared copper film. There is no limitation on the method for casting the solution onto the copper film, but tape casting may be advantageous in that it allows for large-area RCC. In step 2), the solution is applied onto the copper film and then heated at 50 to 100°C for casting, thereby obtaining the RCC. As illustrated in Fig. 3, cross-linking is formed between the curable functional groups of the curable cyclic olefin copolymer included in the solution on the copper film in step 2), thereby densifying the copolymer. This contributes to the improvement of mechanical properties, such as heat resistance and strength, of the RCC including the copolymer.

[0040] The present disclosure has been described in detail through specific implementation examples. These implementation examples are intended to illustrate the present disclosure in detail, and the present disclosure is not limited thereto. It will be apparent that modifications and improvements within the technical scope of the present disclosure are possible by those skilled in the art.

[0041] All simple modifications or changes of the present disclosure fall within the scope of the present disclosure, and the specific scope of protection of the present disclosure will be made clear by the appended claims.

Claims

1. A method for producing a curable cyclic olefin copolymer (COC): a) introducing maleic anhydride into COC to produce a maleic anhydride modified cyclic olefin copolymer; and b) A method for producing a curable cyclic olefin copolymer, comprising the step of polymerizing a monomer having a curable functional group to maleic anhydride of a maleic anhydride-modified cyclic olefin copolymer to produce a curable cyclic olefin copolymer.

2. In claim 1, Step a) is a method for producing a curable cyclic olefin copolymer, performed in the presence of a peroxide.

3. In claim 2, A method for producing a curable cyclic olefin copolymer, wherein the peroxide comprises benzoyl peroxide or dicumyl peroxide.

4. In claim 1, Step a) is a method for producing a curable cyclic olefin copolymer, performed at a temperature of 50 to 180° C.

5. In claim 1, Step a) is a method for producing a curable cyclic olefin copolymer, which is performed using a microwave.

6. In claim 1, A method for producing a curable cyclic olefin copolymer, wherein the method further comprises a precipitation step for removing unreacted reagents after step a) and before step b).

7. In claim 1, A method for producing a curable cyclic olefin copolymer, wherein the monomer having a curable functional group of step b) contains a hydroxyl group or an amine group.

8. In claim 1, Step b) is a method for producing a curable cyclic olefin copolymer, performed at a temperature of 20 to 50° C.

9. In claim 1, A method for producing a curable cyclic olefin copolymer, wherein the method further comprises a precipitation step for removing a monomer having an unreacted curable functional group after step b).

10. As a curable cyclic olefin copolymer, Maleic anhydride modified cyclic olefin copolymer; and A curable cyclic olefin copolymer comprising a monomer having a curable functional group.

11. A method for manufacturing resin coated copper (RCC): 1) a step of preparing a solution containing a curable cyclic olefin copolymer manufactured by the manufacturing method of claim 1; and 2) A method for producing resin-coated copper, comprising the step of casting a solution containing the curable cyclic olefin copolymer onto a copper film.

12. In claim 11, Step 1) is to add 1 to 80 wt% of SiO to a solution containing the curable cyclic olefin copolymer. 2 A method for producing resin-coated copper, comprising the step of adding a.

Images