KR102037254B1 - Conductive thermoset adhesive composition, conductive thermoset adhesive film comprising the same and preparation method thereof - Google Patents

Abstract

Disclosed herein is a conductive thermosetting adhesive composition, a conductive thermosetting adhesive film comprising the same, and a method of manufacturing the same. The conductive thermosetting adhesive composition is a modified polyester resin containing a carboxyl group; Epoxy resins; Conductive metal powder; And antioxidants to improve adhesion, heat resistance, moisture resistance, and provide high reliability (long-term stability) and heat dissipation characteristics.

Description

CONDUCTIVE THERMOSET ADHESIVE COMPOSITION, CONDUCTIVE THERMOSET ADHESIVE FILM COMPRISING THE SAME AND PREPARATION METHOD THEREOF}

Disclosed herein is a conductive thermosetting adhesive composition, a conductive thermosetting adhesive film comprising the same, and a method of manufacturing the same.

In recent years, as the integration technology of semiconductor integrated circuits and the surface mount technology for directly mounting small chip components have been developed in the electronics industry, and electronic devices have been miniaturized, it is necessary to facilitate mounting even in more complicated and narrow spaces. In order to meet these demands, flexible printed circuit boards have been actively developed.

In particular, in the case of flexible printed circuit boards (FPCB), the demand for mobile phones, DVDs, digital cameras, PDPs, etc. is increasing rapidly due to the technological development.

In general, a flexible circuit board used for assembling electronic devices includes a coverlay by forming a circuit pattern on an electrically insulating base film including an adhesive layer and a laminate base film composed of a metal layer, and removing a release base material for temporary protection. It is produced by further laminating another insulating film obtained from the film.

At this time, the conventional conductive thermosetting adhesive film composition used for electronic materials, such as a semiconductor sealing material or a flexible circuit board, consists of an epoxy resin, acrylic rubber containing a carboxyl group, a multifunctional hardening | curing agent, etc. However, the acrylic rubber containing a carboxyl group oxidizes the metal powder contained in an adhesive composition, and deteriorates a characteristic, or the adhesive strength deteriorates and the problem that a metal reinforcement board is easy to peel off arises.

In addition, among other conventional conductive thermosetting adhesive film compositions, adhesive compositions including polyurethane polyurea resins, epoxy resins, and conductive metal fillers are excellent in adhesive strength, but because they contain urethanes, problems of poor heat resistance and heat and moisture resistance occur. do.

Furthermore, in the case of the conductive thermosetting adhesive film composition containing the polyurethane resin, epoxy resin, and copper which have a carboxyl group as a main component, the electrically conductive filler, hardening | curing agent, and a silane coupling agent, by containing the epoxy hardening | curing agent used together with an epoxy compound, On account of the manufacturing process, the curing reaction is initiated by temporary bonding (high temperature), and the curing reaction occurs during storage, so that sufficient adhesive strength may not be obtained in the present bonding (high temperature and high pressure).

Korean Unexamined Patent Publication No. 10-2009-0065156

In one aspect, the present specification is to provide a conductive thermosetting adhesive composition with improved adhesion, heat resistance, moisture resistance.

In another aspect, the present disclosure aims to provide a conductive thermosetting adhesive film comprising the conductive thermosetting adhesive composition.

In another aspect, the present specification is to provide a method for producing the conductive thermosetting adhesive film.

In one aspect, the techniques disclosed herein include a modified polyester resin comprising a carboxyl group; Epoxy resins; Conductive metal powder; And it provides a conductive thermosetting adhesive composition comprising an antioxidant.

In an exemplary embodiment, the modified polyester resin including the carboxyl group may be included in 25 to 35% by weight based on the total weight of the composition.

In an exemplary embodiment, the epoxy resin may be included in 3 to 10% by weight based on the total weight of the composition.

In an exemplary embodiment, the epoxy resin may be one having an equivalent of 170 to 230 g / eq.

In an exemplary embodiment, the conductive metal powder may be included in 50 to 70% by weight based on the total weight of the composition.

In an exemplary embodiment, the antioxidant may be included in 0.1 to 1% by weight based on the total weight of the composition.

In an exemplary embodiment, the antioxidant may be to include a polyphosphoric acid compound.

In another aspect, the technology disclosed herein provides a conductive thermosetting adhesive film comprising the conductive thermosetting adhesive composition.

In another aspect, the techniques disclosed herein include coating the conductive thermosetting adhesive composition on a release film; And drying the coated release film to produce a semi-cured film.

In one aspect, the technology disclosed herein has the effect of providing a conductive thermosetting adhesive composition with improved adhesion, heat resistance, moisture resistance.

In another aspect, the technology disclosed herein has the effect of providing a conductive thermosetting adhesive film comprising the conductive thermosetting adhesive composition.

In another aspect, the technology disclosed herein has the effect of providing a method for producing the conductive thermosetting adhesive film.

Hereinafter, the present invention will be described in detail.

In one aspect, the techniques disclosed herein include a modified polyester resin comprising a carboxyl group; Epoxy resins; Conductive metal powder; And it provides a conductive thermosetting adhesive composition comprising an antioxidant.

Conventional conductive thermosetting adhesive composition is poor in high reliability properties, high defect rate in the component mounting process, while the conductive thermosetting adhesive composition according to the present specification has the effect of providing high reliability (long-term stability) and heat dissipation properties.

The conductive thermosetting adhesive composition includes a modified polyester resin including a carboxyl group rather than a polyurethane resin including a conventional carboxyl group and exhibits excellent long-term stability characteristics.

In an exemplary embodiment, the modified polyester resin including the carboxyl group is 25% by weight, 26% by weight, 27% by weight, 28% by weight, 29% by weight, 30% by weight based on the total weight of the composition It may be included in at least%, 31% by weight, 32% by weight, at least 33% by weight or at least 34% by weight.

In another exemplary embodiment, the modified polyester resin including the carboxyl group is 35% by weight, 34% by weight, 33% by weight, 32% by weight, 31% by weight or less, based on the total weight of the composition It may be included in the wt% or less, 29 wt% or less, 28 wt% or less, 27 wt% or less, or 26 wt% or less.

In an exemplary embodiment, the modified polyester resin including the carboxyl group may be one having an acid value of 25 to 45 mgKOH / g. Accordingly, when the acid value of less than 25 mgKOH / g has a small carboxyl group to prevent the problem that the adhesion to the substrate is lowered, if it exceeds 45 mgKOH / g because of the oxidation reaction with the metal powder mixed due to the high acid value There is an effect to prevent problems that may lower the electrical conductivity, liquid stability or productivity.

The conductive thermosetting adhesive composition is characterized by forming a conductive thermosetting adhesive film by crosslinking a modified polyester and an epoxy resin without adding an epoxy curing agent used in combination with an epoxy compound. In the case of containing an epoxy curing agent, there is a problem in that sufficient bonding strength is not obtained at the time of the main bonding due to the curing reaction caused by the high heat during the temporary bonding and the secondary heat curing through the main bonding.

In an exemplary embodiment, the epoxy resin is at least 3% by weight, at least 4% by weight, at least 5% by weight, at least 6% by weight, at least 7% by weight, at least 8% by weight or 9% by weight based on the total weight of the composition. It may be included as above.

In another exemplary embodiment, the epoxy resin is 10% by weight, 9% by weight, 8% by weight, 7% by weight, 6% by weight, 5% by weight or 4% by weight based on the total weight of the composition. It may be included in% or less.

In an exemplary embodiment, the epoxy resin is a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a bisphenol S type epoxy resin, a phenol novolac type epoxy resin, a cresol novolac type epoxy resin, an alicyclic epoxy resin, an aliphatic chain type At least one selected from the group consisting of diglycidyl ethers of epoxy resins, diglycidyl ethers of biphenols, diglycidyl ethers of naphthalene diols, diglycidyl ethers of phenols, and diglycidyl ethers of alcohols Can be.

In an exemplary embodiment, the epoxy resin may be one having an equivalent of 170 to 230 g / eq, more preferably 170 to 200 g / eq. Equivalent of the epoxy resin acts as a factor that can affect the crosslinking reaction with the modified polyester resin, and by using an epoxy resin having an equivalent in the above range, the crosslinking reaction with the modified polyester resin is not perfect, so that the film properties There is an effect to prevent problems that can fall and prevent the problem that the heat resistance can be reduced due to the unreacted epoxy resin other than crosslinking with the modified polyester resin. In addition, there is an effect of increasing the heat resistance of the resin by using an epoxy resin having an equivalent in the above range.

In an exemplary embodiment, the conductive thermosetting adhesive composition may include 25 to 50 wt% or 30 to 50 wt% of the mixed weight of the modified polyester resin and the epoxy resin including the carboxyl group based on the total weight of the composition to improve reliability. It may be an improvement.

In an exemplary embodiment, the conductive metal powder may be included in at least 50% by weight, 55% by weight, 60% by weight or 65% by weight based on the total weight of the composition. The conductive thermosetting adhesive composition according to the present disclosure has an advantageous effect in reducing manufacturing costs because it does not have to maintain the initial shielding rate by increasing the content of the metal powder to reduce the effect of oxidation. In addition, since deterioration due to oxidation of the conductive metal powder is prevented and easy to store, cost reduction may be economical.

In another exemplary embodiment, the conductive metal powder may be included in 70 wt% or less, 65 wt% or less, 60 wt% or less or 55 wt% or less based on the total weight of the composition.

In an exemplary embodiment, the conductive metal powder may be one or more selected from the group consisting of gold, silver, copper, nickel, tin, zinc, tungsten, aluminum, stainless, iron, graphite, carbon black, diamond, and CNT. have.

In an exemplary embodiment, the conductive metal powder may be one or more of gold, silver, copper, nickel, iron, silver coated copper powder and silver coated nickel powder having excellent electrical conductivity, and considering electrical conductivity or economical efficiency. Silver coated copper powder may be preferred.

In one exemplary embodiment, the conductive metal powder may have a particle size of 5 to 30 ㎛, preferably 10 to 20 ㎛. Accordingly, the particle size is small, the electrical contact formation rate is low to prevent the problem of not being able to obtain sufficient electrical conductivity compared to the input amount, the particle size is large, the size of the powder is too large compared to the thickness of the adhesive film conductive adhesive film of uniform physical properties It is effective in preventing problems that cannot be obtained.

In an exemplary embodiment, the modified polyester resin and the epoxy resin is mixed in a weight ratio of 2 to 12: 1, 4-12: 1, 6-12: 1, 8-12: 1 or 10-12: 1. It may be.

In an exemplary embodiment, the metal powder and the epoxy resin may be mixed in a weight ratio of 5 to 20: 1, 10 to 20: 1, 5 to 15: 1, 5 to 10: 1 or 10 to 15: 1. have.

In an exemplary embodiment, the metal powder and the modified polyester resin may be mixed in a weight ratio of 2 to 3: 1 or 2 to 2.5: 1.

The conductive thermosetting adhesive composition includes an antioxidant to prevent oxidation of the conductive metal powder due to a resin containing a carboxyl group, thereby preventing a decrease in shielding performance, and preventing a change in viscosity of the coating liquid to uniformly disperse the metal powder in the polymer resin. In the case of forming a film, a uniform coating film can be obtained, thereby providing a high shielding rate and high reliability characteristics.

In an exemplary embodiment, the antioxidant may be included in 0.1 to 1% by weight or 0.5 to 1% by weight based on the total weight of the composition.

In an exemplary embodiment, the antioxidant may be a polyphosphate-based antioxidant, benzotriazole-based antioxidant, and the like.

In an exemplary embodiment, the antioxidant may exhibit excellent electromagnetic shielding performance uniformly in all parts of the conductive layer, including the polyphosphoric acid-based compound, and prevents partial peeling or separation problems due to deterioration of interlayer adhesion, and high reliability. Has the effect of providing.

In an exemplary embodiment, the conductive thermosetting adhesive composition may further include a silane coupling agent to further improve dispersibility or coating property of the metal powder.

In an exemplary embodiment, the silane coupling agent may be included in 0.1 to 1% by weight based on the total weight of the composition.

In another aspect, the technology disclosed herein provides a conductive thermosetting adhesive film comprising the conductive thermosetting adhesive composition.

In another aspect, the techniques disclosed herein include coating the conductive thermosetting adhesive composition on a release film; And drying the coated release film to produce a semi-cured film.

In one exemplary embodiment, the conductive thermosetting adhesive composition may be to form a coating film through a coating method such as Comma, Slot die, Gravure and the like.

In an exemplary embodiment, the coated release film may be to form a semi-cured film by removing the organic solvent through hot air drying.

Hereinafter, the present invention will be described in more detail with reference to Examples. These examples are only for illustrating the present invention, it will be apparent to those skilled in the art that the scope of the present invention is not to be construed as limited by these examples.

Experimental Example

To the composition of the thermosetting conductive adhesive composition of Table 1 according to the conventional method to prepare a thermosetting conductive adhesive film. In Table 1, the composition unit of each component is weight% (wt%), antioxidant 1 is polyphosphoric acid antioxidant, antioxidant 2 is benzotriazole-based antioxidant. The thermosetting conductive adhesive film thus prepared was thermally laminated at SUS 304 using a thermal laminator at a temperature of 150 ° C., and the base film treated with the release surface was removed. Generally, since the thermosetting conductive adhesive film is used in a state of being laminated with SUS 304 when used in a camera module and a connector, the physical properties were also evaluated in the state of being laminated. The thermosetting conductive adhesive film having SUS 304 on the surface of FPCB (FCCL: Flexible Copper Clad Laminated and C / L: Coverlay Laminated Substrate) plated with gold plating was again laminated in the same manner. After the lamination, the thermosetting conductive adhesive was cured using a hot press equipment at a temperature of 170 ° C., a pressure of 30 kgF / cm ² , and a time of 60 minutes to prepare an evaluation specimen, and the following physical properties were measured.

1. Adhesion (kgF / cm)

The adhesion was measured on the gold plated surface and the PI surface of C / L. The adhesion spec is more than 1.0 kgF / cm.

2. Heat resistance

The specimen prepared as described above was cut into 2cm × 2cm and floated on a bath (288 ° C.) to confirm bubble generation and resistance characteristics.

3. Electrical Conductivity

The electrical conductivity was evaluated by the coupon produced by Yulchon, and there was no spec. The coupon consists of 0.5, 1.0, 1.5 mm hole and conductivity measurement part based on FPCB substrate, and the two parts are gold plated. The distance between the holes is 12 mm and the distance between the holes and the measuring part is between 15 mm and 35 mm. The adhesive laminated with SUS 304 was placed in two holes, and the electrical conductivity of the two measuring units was measured using a multitester.

4. Long term stability

After leaving for 96 hours at high temperature and high humidity (85% humidity 85%), the adhesion, heat resistance, and electrical conductivity were checked.

Furtherance Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Comparative Example 1 Comparative Example 2 Thermosetting Conductive Adhesive Film Layer Modified Polyester Resin (NPE-2300)
Nanuk Chemical Co., Ltd. 100 100 100 100 100 100 100 100 Polyurethane Resin (UR-3600) 100 Epoxy Resin (YDCN)
Kukdo Chemical 10 5 10 20 10 10 20 10 10 Epoxy curing agent
(Diaminodiphenylsulfone, DDS) One Metal Powder (FCC2000)
Fukuda Corporation 200 200 200 200 100 300 200 200 200 Metal antioxidants 1 One One One One One One One Antioxidants 2 One evaluation Initial Adhesion 1 (Polyimide)
(kgF / cm) 2 2 2 1.5 2.2 1.3 1.9 2 One Initial Adhesion 2 (Gold Plated Surface)
(kgF / cm) 1.2 1.3 1.2 1.2 1.3 0.6 1.2 0.7 0.8 Initial electrical conductivity 0.2 0.2 0.2 0.2 0.9 0.1 0.2 0.2 0.4 Heat resistance O X O O O X X X O Adhesion after moist heat resistance 1
(Polyimide)
(kgF / cm) 2 2 2 2 2.1 1.1 1.8 2 1.1 Adhesion after Moisture and Heat Resistance 2
(Gold plated noodles)
(kgF / cm) 1.2 0.8 1.2 One 1.3 0.6 1.1 0.5 0.9 Electrical Conductivity after Moisture and Heat Resistance
(Ω) 0.4 0.3 0.2 0.2 1.5 0.1 0.3 0.2 0.4

As a result, when using the thermosetting conductive adhesive composition according to the present specification compared to Comparative Examples 1 and 2 containing a polyurethane resin or an epoxy curing agent, it was confirmed that the adhesion, heat resistance, and electrical conductivity were all improved. In addition, considering the performance of the conductive bonding, ease of manufacture and supply, etc., it was confirmed that the use of a polyphosphate-based antioxidant as an antioxidant exhibits an excellent effect. In addition, the mixing ratio of the modified polyester resin, the epoxy resin, and the metal powder affected the adhesion, heat resistance, and electrical conductivity of the thermosetting conductive adhesive film. There was a disadvantage.

As described above, specific portions of the present disclosure have been described in detail, and for those skilled in the art, these specific techniques are merely preferred embodiments, and the scope of the present disclosure is not limited thereto. Will be obvious. Thus, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

Claims (9)

Modified polyester resins containing carboxyl groups;
Epoxy resins;
Conductive metal powder; And
Contains a polyphosphate-based antioxidant,
The modified polyester resin and the epoxy resin containing the carboxyl group are mixed in a weight ratio of 8 to 10: 1,
A conductive thermosetting adhesive composition containing no urethane resin.
The method of claim 1,
The modified polyester resin including the carboxyl group is contained in 25 to 35% by weight based on the total weight of the composition, conductive thermosetting adhesive composition.
The method of claim 1,
The epoxy resin is contained in 3 to 10% by weight based on the total weight of the composition, conductive thermosetting adhesive composition.
The method of claim 1,
Wherein the epoxy resin has an equivalent of 170 to 230 g / eq.
The method of claim 1,
The conductive metal powder is contained in 50 to 70% by weight based on the total weight of the composition, conductive thermosetting adhesive composition.
The method of claim 1,
The antioxidant is contained in 0.1 to 1% by weight based on the total weight of the composition, conductive thermosetting adhesive composition.
The method of claim 1,
The modified polyester resin containing the conductive metal powder and the carboxyl group is mixed in a weight ratio of 2 to 2.5: 1, conductive thermosetting adhesive composition.
A conductive thermosetting adhesive film comprising the conductive thermosetting adhesive composition according to any one of claims 1 to 7.
Coating a conductive thermosetting adhesive composition according to any one of claims 1 to 7 on a release film; And
Method of manufacturing a conductive thermosetting adhesive film comprising the step of drying the coated release film to produce a semi-cured film.