JP2000053934A - Adhesive composition and its precursor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an adhesive composition having improved properties as an adhesive film for protecting a flexible print circuit board, especially dimensional stability, impact resistance, stream friction at the time of thermal attachment by pressure, and adhesiveness by allowing a thermoplastic resin to include an adhesive polymer, and further dispersing an inorganic colloid in the resin component. SOLUTION: This adhesive composition includes a resin component comprising (A) a thermoplastic resin, (B) an epoxy resin and (C) a hardening agent. The component A contains an adhesive polymer (preferably an alkyl acrylate- aromatic acrylate copolymer), and an inorganic colloid dispersed in the resin component. Preferably, the component B includes a brominated epoxy resin, and the inorganic colloid is antimony pentoxide colloid. The proportion of the total of the brominated epoxy resin and the antimony pentoxide colloid is preferably regulated so as to be 13-60 wt.% based on the whole amount of the objective composition. Dicyandiamide is preferable as the component C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a thermoplastic resin,
The present invention relates to an adhesive composition based on a resin component containing an epoxy resin and a curing agent, and an adhesive composition precursor that is a raw material of such an adhesive composition.

[0002]

2. Description of the Related Art As an adhesive film for an FPC (Flexible Printed Wiring Board) protective film, an adhesive composition comprising a combination of various thermoplastic resins and an epoxy resin which is a thermosetting resin is known (for example, Japanese Patent Application Laid-Open No. -13
2710, JP-A-9-125037, JP-A-6-256746, JP-A-5-339556, JP-A-5-5085, and JP-A-3-6280
JP, JP-A-2-145676, JP-A-62-267.
274690, JP-A-60-130666, JP-A-1-135844, JP-A-61-43
550, etc.).

[0003] Among the adhesive films disclosed in the above publication, an adhesive film formed from a composition containing a phenoxy resin or / and an adhesive acrylic polymer as a thermoplastic resin, an epoxy resin, and a curing agent includes: Relatively excellent performance such as heat resistance and adhesion to metal parts,
It has been particularly useful so far. The above publication also discloses that a polyester polyol resin and various elastomers are contained as the thermoplastic resin. As a hardening agent, didiandiamide is used relatively frequently because of its particularly high potential. Further, it is considered that the adhesive acrylic polymer preferably has a carboxyl group, a hydroxyl group, or an epoxy group in a molecule. For example, in the compositions disclosed in JP-A-6-256746 and JP-A-5-339556,
Epoxy resin phase (recognizing that the whole is sea-island structure,
It discloses that the phase (for example, a sea-like phase) and the phase of a phenoxy resin and an acrylic polymer (for example, an island-like phase) are effectively separated, thereby improving repairability. Here, “repairability” means that when a circuit component or a circuit as an adherend is defective, the work of removing the adhesive film from the adherend is easy. Replace with a circuit component or circuit, glue it again,
This is a property that means that it is possible to easily assemble. Therefore, these two publications disclose nothing about means for effectively improving dimensional stability, impact resistance, flow resistance at the time of thermocompression bonding (prevention of a large flow that causes protrusion), and adhesiveness. Not.

On the other hand, in the general field of resin compositions, it is known as a conventional technique to improve the flame retardancy of a resin composition by adding a combination of a brominated epoxy resin and antimony pentoxide. For example, US Pat.
No. 9,808, No. 4,105,622, No. 5,2
No. 90,835, No. 5,221,704, No. 5,
Nos. 098,781, 5,681,879, 5,034,439, 5,180,767, 5,308,565, 5,719,225 and No. 5,536,970 can be cited as a document introducing such conventional techniques. According to this technique, the antimony pentoxide powder is usually mixed with other resin components to form a flame retardant composition. However, although antimony pentoxide powder is relatively inexpensive, its average particle size is usually 0.5 μm or more.

[0005]

However, the adhesive composition containing thermoplastic resin, epoxy resin and dicyandiamide as the main components as described above, however, has a relatively small dimensional change caused by the stress generated in the heat curing process. It has the disadvantage of being large. Such reduction of dimensional change, that is, improvement of dimensional stability, is required to be further improved in the use of an adhesive for an FPC protective film. However, the above-mentioned conventional adhesive composition can meet such a demand. Was very difficult.

On the other hand, when forming an adhesive composition containing the above-mentioned antimony pentoxide powder, the antimony pentoxide powder is mixed with an effective amount of the antimony pentoxide powder in a liquid mixture of another resin component and a solvent. Because of sedimentation due to gravity, it was difficult to realize a state (structure) in which the components were uniformly mixed. Such a non-uniform structure causes a decrease in dimensional stability and adhesiveness, and significantly lowers the performance as an adhesive for an FPC protective film.

In the above-mentioned conventional adhesive film,
(I) to reduce the flow of the adhesive during thermocompression bonding, to prevent protrusion after bonding (for example, to flow out and cover the soldered portion), and (ii) an adhesive film (before completion of curing) ) Is not intended to improve the impact resistance and prevent breakage (cracking, etc.) when punching a film having a predetermined shape and dimensions according to the parts to be bonded. No means for solving the problem is disclosed.

That is, an object of the present invention is to provide an adhesive composition containing a thermoplastic resin, an epoxy resin, and a curing agent as an adhesive for an FPC protective film, in particular, dimensional stability and impact resistance. Another object of the present invention is to provide an adhesive composition having improved flow resistance and adhesion during thermocompression bonding. Another object of the present invention is to provide an adhesive composition precursor that can be advantageously used as a raw material in providing such an adhesive composition.

[0009]

SUMMARY OF THE INVENTION In one aspect, the present invention provides an adhesive composition containing a resin component containing a thermoplastic resin, an epoxy resin, and a curing agent. In the above, there is provided an adhesive composition, wherein the thermoplastic resin contains a tacky polymer, and the resin component further contains an inorganic colloid dispersed in the resin component.

Here, in the adhesive composition of the present invention, preferably, the epoxy resin contains a brominated epoxy resin,
The inorganic colloid is an antimony pentoxide colloid, and the total ratio of the brominated epoxy resin and the antimony pentoxide colloid is in the range of 13 to 60% by weight based on the total amount of the adhesive composition. Things.

According to another aspect of the present invention, there is provided an adhesive composition precursor which provides the adhesive composition of the present invention after drying, wherein the adhesive composition precursor comprises (i)
An adhesive composition precursor, comprising: the resin component; and (ii) an inorganic particle sol containing the dispersion medium and the inorganic colloid dispersed in the dispersion medium. I do.

The preferred method for producing the above-mentioned adhesive composition precursor is as follows: (a) Among the resin components, a thermoplastic resin other than the epoxy resin, the curing agent, and the tacky polymer added as necessary. Mixing a first resin solution in which a resin is dissolved in a first solvent and a second resin solution in which the adhesive polymer is dissolved in a second solvent to form a base resin solution; This is a method in which an inorganic composition sol is added to a liquid, and an adhesive composition precursor composed of a uniform dispersion liquid formed by mixing is obtained. The details of the first and second solvents and the like will be described later.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the embodiments. The adhesive composition of the present invention is a composition based on a resin component containing a thermoplastic resin, an epoxy resin, and a curing agent, as described above,
It is characterized by containing an adhesive polymer as a thermoplastic resin and an inorganic colloid dispersed in a resin component. The adhesive composition of the present invention has the following properties due to its constitution as described above: (a) dimensional stability, particularly after heat treatment (for the purpose of completion of curing, etc.) further performed after thermocompression bonding. Dimensional stability, (b) impact resistance (especially before completion of curing), (c) flow resistance during thermocompression bonding (for example, prevention of large flow that may cause protrusion to the soldered portion), and (d) adhesion Properties can be effectively improved.

For example, (a) the dimensional stability can be described by referring to the dimensional change rate (the measuring method will be described later).
It can be improved to the extent that it shows 0.1% or less.
(B) Impact resistance is measured by applying a polymer film formed by applying an adhesive composition on a polymer film such as polyimide.
When a hole having a diameter of 10 mm is punched out in the adhesive film laminate, it can be improved to the extent that cracks do not occur around the hole. (C) The flow resistance during thermocompression bonding is:
Open the 1 mm ² × 1 mm ² of the hole in the adhesive film comprising the adhesive composition, a rolled copper foil having a thickness of 30μm so as to cover the hole 120 ° C., when thermal compression bonding at about 40 kg / cm ² condition, It can be improved so that the protrusion of the adhesive composition at the edge of the hole is less than 0.6 mm. further,
(D) Adhesiveness can be effectively increased when the adhesive composition is used for adhesion between a metal foil such as a copper foil and a polymer film such as a polyimide (for example, peel adhesion) Can be increased to 500 g / cm or more).

In a preferred embodiment of the present invention, the epoxy resin comprises a brominated epoxy resin, the inorganic colloid is a colloid of antimony pentoxide, and the brominated epoxy resin and the antimony pentoxide are combined. Is 1 to the total amount of the adhesive composition.
An adhesive composition characterized by being in the range of 3 to 60% by weight. Here, the “brominated epoxy resin”, when used in the present specification, is an epoxy resin having a bromine atom introduced in a molecule, for example,
It has a structure in which one or more hydrogen atoms of a benzene ring in a molecule of a bisphenol-type epoxy resin are substituted with bromine. Further, epoxy resins other than “brominated epoxy resin” are particularly referred to as “non-brominated epoxy resin” in the specification of the present application to be distinguished.

Another feature of the present invention is that an inorganic colloid and a tacky polymer are used in combination in an adhesive composition based on an epoxy resin and a curing agent. Inorganic colloids, in particular, effectively improve the (a) dimensional stability and (c) the flow resistance during thermocompression bonding. In such an action, it is important that the inorganic particles are colloids (the definition will be described later). The tacky polymer helps to improve the above (a) and (c) of the inorganic colloid, and at the same time, effectively improves the above (b) impact resistance, particularly as a synergistic effect in combination with the inorganic colloid. In addition, the inorganic colloid and the tacky polymer have a function of further enhancing the excellent adhesive strength of the adhesive composition based on the epoxy resin and the curing agent.

The adhesive composition according to this preferred form of the present invention is manufactured by UL under the name of Underwriter's Laboratories Inc.
Pass the V0 level of the −94 standard (ie, UL9
4 (evaluated as level V0 specified in the 4 standards). In such an adhesive composition, if the total ratio of the brominated epoxy resin and the colloid of antimony pentoxide is less than 13% by weight based on the total amount of the adhesive composition, the above-mentioned V0 level is passed. On the other hand, if it exceeds 60% by weight, the peel adhesive strength decreases.

The term “resin component” as used herein refers to an epoxy resin, a curing agent,
It refers to a mixture of the tacky polymer and optional additional components and does not include solvents or inorganic colloids. The additional components that can be added as desired are not limited to those listed below. However, (i) thermoplastic resins such as phenoxy resins and polyester polyols;
Examples include i) a curing accelerator, (iii) additives such as a tackifier and a plasticizer, and the like.

The components constituting the adhesive composition of the present invention, the adhesive composition and its precursor of the present invention, and the adhesive film using the same will be described in more detail as follows. [Adhesive polymer] The function of the adhesive polymer is considered to be as follows. The tacky polymer forms a fine phase-separated structure in the adhesive composition having a size of about 1 nm to 1 μm (for example, a diameter when spherical). This microstructure is entangled with molecules of another polymer (such as an epoxy resin or a phenoxy resin) in the adhesive composition, and can simultaneously improve flow resistance and impact resistance during thermocompression bonding. When the microstructure has a shape other than a spherical shape (an elliptical particle, an irregular shape, or the like), the maximum dimension (a major axis in the case of an elliptic particle, etc.) is usually regarded as the size.

The content of the adhesive polymer is not particularly limited as long as the effects of the present invention are not impaired, but is usually 0.1 to 25% by weight based on the total amount of the adhesive composition. If the amount is too small, the properties of the above items (a) to (d) may not be improved. On the other hand, if the amount is too large, other properties (for example, flame retardancy to be described later) as the adhesive composition are deteriorated. There is a risk. From such a viewpoint, a suitable content ratio of the adhesive polymer is in a range of 1 to 10% by weight based on the total amount of the adhesive composition.

Here, the term "adhesive polymer" refers to a polymer that exhibits adhesive properties at room temperature (about 25 ° C.), and an acrylic polymer is preferred. This is because the adhesive force can be effectively increased. Further, as the acrylic polymer, an alkyl acrylate-aromatic acrylate copolymer is preferable. This is because the aromatic acrylate in the polymer molecule has good compatibility with the epoxy resin, and easily interacts with each other. In addition, when the adhesive composition contains a phenoxy resin, the alkyl acrylate-aromatic acrylate copolymer has a good interaction with the phenoxy resin, and more effectively reduces flow resistance and impact resistance during thermocompression bonding. Can be improved.

When an alkyl acrylate-aromatic acrylate copolymer is used as the acrylic polymer,
The weight ratio (A: P) of the alkyl acrylate (A) and the aromatic acrylate (P) in the copolymer is not particularly limited as long as the copolymer exhibits tackiness.
Preferably 30:70 to 99: 1, particularly preferably 40: 5
The range is 0 to 90:10. If the amount of the aromatic acrylate in the copolymer is too small, the flow resistance and impact resistance at the time of thermocompression bonding may be reduced, and if the amount of the aromatic acrylate is too large, the dimensional stability may be reduced. It may decrease. Specific examples of the above alkyl acrylate include, for example, butyl acrylate, isooctyl acrylate, 2-ethylhexyl acrylate, and the like. Specific examples of the aromatic acrylate include, for example, phenoxyalkyl acrylate.

The acrylic polymer may contain another monomer unit instead of or together with the alkyl acrylate or aromatic acrylate constituting the acrylic polymer. Such monomer units are, for example,
Examples thereof include alkyl methacrylate, (meth) acrylic carboxylic acid (such as acrylic acid), (meth) acrylic polycarboxylic anhydride, and alkoxy (meth) acrylate (such as acetoacetoxyacrylate). However, when the adherend to which the adhesive composition is applied contains a metal, the acrylic polymer used is preferably substantially free of carboxylic acid. This is because corrosion of the adherend can be effectively prevented. [Inorganic colloid] Since the inorganic colloid is usually contained in the dispersion in the form of colloid particles, the colloid particles can be stably dispersed without sedimentation due to gravity. Therefore, in the adhesive composition of the present invention formed by drying such a dispersion, a state in which the components are uniformly mixed can be realized, and the peel adhesive strength and the dimensional stability can be effectively improved. .

The content of the inorganic colloid in the adhesive composition is not particularly limited as long as the effects of the present invention are not impaired, but is usually in the range of 1 to 50% by weight based on the total amount of the adhesive composition. . If the amount is less than 1% by weight, the dimensional stability may decrease.
Peel adhesion may be reduced. From such a viewpoint, a preferable content ratio of the inorganic colloid is in a range of 2 to 45% by weight based on the total amount of the adhesive composition.

Here, the “inorganic colloid” is usually a fine particle having an average particle diameter in the range of 1 to 100 nm. For example, it is preferable that the inorganic particle sol and the resin component are mixed and dispersed and contained in the resin component. The inorganic particle sol is usually a mixture of (i) a dispersion medium and (ii) the inorganic colloid dispersed in the dispersion medium. As such inorganic particle sol, antimony pentoxide sol, silica sol and the like can be used. [Resin Component] The resin component usually comprises the following three components: 1) a thermoplastic resin containing an adhesive polymer, 2) an epoxy resin, and 3) a curing agent. In one preferred form of the invention, the resin component comprises: a) a phenoxy resin, b) a non-brominated epoxy resin, c) a brominated epoxy resin, d) a sticky polymer, and e) dicyandiamide. Here, components other than the already described d) adhesive polymer will be described in detail.

A) Phenoxy resin is one of the components as a thermoplastic resin that contributes to the improvement of the adhesive strength of the composition. The phenoxy resin mainly contributes to the improvement of the peel adhesion by the intermolecular attractive force between the hydroxyl group of the polymer molecule constituting the phenoxy resin and the surface of the adherend and the flexibility (flexibility) of the resin itself. The type and amount of the phenoxy resin are preferably selected so that the glass transition temperature of the cured composition does not become 70 ° C. or lower. Thereby, the dynamic bending resistance of the cured composition can be enhanced, and breakage or peeling of the adhesive layer during use can be effectively prevented.

B) The non-brominated epoxy resin has an effect of increasing the glass transition temperature of the cured composition by reacting with a curing agent such as diiandiamide. A high glass transition temperature is advantageous for increasing heat resistance. It is preferable to select the type and amount of the non-brominated epoxy resin so that the glass transition temperature of the cured composition does not become 70 ° C. or lower. As the non-brominated epoxy resin, for example, epoxy resins such as bisphenol A type, bisphenol F type, cresol novolak type, and phenol novolak type can be used. When a brominated epoxy resin is used, a non-brominated epoxy resin is not an essential component, but it is preferable to contain both types of epoxy resins in order to effectively increase both adhesive strength and flame retardancy. is there.

C) The brominated epoxy resin increases the flame retardancy of the composition, as described above. Further, it also has an effect of increasing the solubility of the phenoxy resin in a specific solvent (for example, a mixed solvent containing methyl ethyl ketone and methanol). The mixed solvent of methyl ethyl ketone and methanol is
Evaporation rate is relatively high. Therefore, it is preferable to combine the brominated epoxy resin and the phenoxy resin in order to reduce the amount of the residual solvent in the adhesive composition (such as an adhesive film) after drying and to realize a uniform structure composed of each component. . Further, the brominated epoxy resin has the same action as the non-brominated epoxy resin due to the reaction with the curing agent. The type and amount of the brominated epoxy resin are preferably selected so as to balance the flame retardancy of the composition, the solubility of the phenoxy resin, and the glass transition temperature (above 70 ° C.) of the composition after curing. It is. As the brominated epoxy resin, for example, brominated bisphenol A type epoxy resin can be used.

E) Dicyandiamide is an effective curing agent for components b) and c) above. The type and amount of dicyandiamide are preferably selected in the same manner as in the other resin components. In addition, as described above, the resin component may include other additional components in addition to the components a) to e). It is preferable that the amount of such an additional component is selected in the same manner as the above-mentioned other resin components.

The content of the resin component other than the adhesive polymer contained in the adhesive composition is not particularly limited as long as the effects of the present invention are not impaired. For example, taking the case where a phenoxy resin is further contained as a thermoplastic resin as an example, the content ratio of a) a phenoxy resin, b) a non-brominated epoxy resin, c) a brominated epoxy resin, and d) a curing agent is as follows. Usually, a) 40 to 9 based on the total components
1.5% by weight, b) 4 to 40% by weight, c) 4 to 50% by weight, and d) 0.1 to 7% by weight, preferably
a) 50-90% by weight, b) 5-35% by weight, c) 5-%
40% by weight, and d) 0.5-5% by weight. When configured to contain each of the above components at a ratio within the above-defined range, an adhesive composition precursor containing the resin component and a solvent (methyl ethyl ketone, methanol, ethyl alcohol, or the like) is used. In the formed adhesive composition (after drying), it is easy to realize a state in which the components are uniformly mixed.

The "curing agent" is a compound that can react at least with the epoxy resin, for example, a curing reaction or a crosslinking reaction, and is preferably dicyandiamide or a derivative thereof. Dicyandiamide and its derivatives have excellent potential and effectively enhance the storage stability of the adhesive composition and its precursor. [Adhesive Composition Precursor] The adhesive composition precursor is a raw material of the adhesive composition that gives the adhesive composition of the present invention after drying. This precursor usually comprises the above resin component, particles of an inorganic colloid such as a colloid of antimony pentoxide, and a solvent.

The inorganic colloid is usually mixed with the above-mentioned other components in the form of a sol, and is uniformly dispersed in a vehicle comprising the above-mentioned resin component and a solvent. Such a sol is usually one in which colloid particles are dispersed in a dispersion medium containing an organic solvent. The solvent of the sol is preferably selected in consideration of the solubility in the resin component. Among them, methyl ethyl ketone is preferred. This is because the solubility in the resin component is good, and there is no risk of impairing the dispersion stability of the sol (particles) in the precursor. The concentration of the inorganic colloid in the adhesive composition precursor is usually in the range of 1 to 50% by weight.

Although the adhesive composition precursor of the present invention can be produced according to various methods, the production method will be described with reference to the case where antimony pentoxide colloid is used as the inorganic colloid. It is as follows. First, among the resin components, a thermoplastic resin other than an “adhesive polymer” such as an epoxy resin, a curing agent, and a phenoxy resin added as needed is dissolved in a first solvent to prepare a first resin liquid. I do. On the other hand, a second resin solution in which the adhesive polymer is dissolved in a second solvent is prepared. Next, the first and second resin liquids are mixed to prepare a base resin liquid. The mixing means is, for example, a high-speed mixer, a planetary mixer, a homomixer, a sand mill, or the like. The solid content concentration of the base resin liquid is usually 5%.
７０70% by weight.

Further, an antimony pentoxide sol is added to the mother resin solution prepared as described above, and a uniform dispersion is prepared by using an appropriate mixing means. The uniform dispersion obtained in this manner is the intended adhesive composition precursor. According to such a production method, a precursor containing antimony pentoxide particles uniformly and stably dispersed in the resin component can be easily prepared. The same means as described above can be used for mixing the base resin liquid and the antimony pentoxide sol.

In the mixing of the base resin liquid, it is preferable that the two resin liquids are in a state of microphase separation from each other. That is, the first solvent and the second solvent are preferably different from each other, depending on the types and concentrations of the components contained in the first and second resin liquids. The adhesive composition precursor of the present invention formed from the base resin liquid in such a microphase-separated state, the adhesive composition formed by drying the precursor, a phase containing a tacky polymer, It is possible to easily realize a state in which the phase containing no conductive polymer is microphase-separated from each other, and the above effects (dimensional stability, impact resistance, flow resistance during thermocompression bonding, etc.) can be further enhanced.

The microphase-separated structure in the adhesive composition preferably has a structure in which one phase forms an “island” having a size (diameter) of 1 μm or less and is uniformly dispersed in the “sea” of the other phase. It is. The phase forming the “island” is preferably a “phase containing a sticky polymer”. In this case, the epoxy resin and the curing agent are usually in the "sea" phase. Further, when using a `` thermoplastic resin other than the adhesive polymer '' such as a phenoxy resin, the `` thermoplastic resin other than the adhesive polymer '' is preferably present in the `` sea '' phase. And the hardener is "sea" or "island"
It may be present in any of the phases.

In the preparation of the first resin liquid, the first solvent used is usually selected from good solvents for thermoplastic resins other than "adhesive polymers" such as epoxy resins, curing agents and phenoxy resins. The second solvent used for preparing the second resin liquid is a good solvent for the adhesive polymer,
In addition, a poor solvent for the epoxy resin, the curing agent and the phenoxy resin is selected. For example, when the adhesive polymer is an acrylic polymer, the first solvent is a mixed solvent of methyl ethyl ketone (MEK) and methanol, and the second solvent is (i) ethyl acetate, butyl acetate. Or a mixed solvent of (ii) a main solvent composed of an ester solvent and a co-solvent composed of another solvent. As the co-solvent, one or a mixture of two or more selected from toluene, isopropanol, acetone and MEK can be used. In the second solvent,
When it is used as a mixed solvent of a main solvent and a co-solvent, the weight ratio (P: S) of the main solvent (P) and the co-solvent (S)
Is usually in the range of 100: 0 to 55:45.

In the first solvent, the weight ratio of methyl ethyl ketone (MEK) to methanol (MeOH) (Me
OH / MEK) is usually 0.005 to 0.4. When the ratio (MeOH / MEK) is less than 0.005, the solubility of dicyandiamide decreases, and when it exceeds 0.4, the solubility of a thermoplastic resin such as a phenoxy resin decreases. Mixing may be difficult.

The first solvent is a solvent other than methyl ethyl ketone and methanol, for example, ethanol,
Isopropyl alcohol, n-propyl alcohol, n
-Butyl alcohol, sec. -Butyl alcohol, t
Alcohols such as -butyl alcohol; nitrogen-containing solvents such as acetonitrile; and the like. Among them, ethanol has good solubility in dicyandiamide, has a lower evaporation rate than methyl ethyl ketone, and does not significantly reduce the evaporation rate of the mixed solvent. Therefore, the uniformity of the coating film can be effectively improved without lowering the drying speed of the coating film.

The adhesive composition precursor of the present invention is a dispersion having excellent storage stability in which the inorganic colloid is stably dispersed in the base resin liquid. Further, in the precursor composition in the above example, the two resin liquids in the base resin liquid are dispersion liquids in which the micro phase is stably separated from each other. Therefore, the user purchases such a stable dispersion from a supplier, stores it, and, when desired, applies and dries it.
An adhesive film comprising the adhesive composition of the present invention can be easily formed.

The adhesive composition precursor may contain various additives as long as the effects of the present invention are not impaired. Suitable additives are, for example, surfactants, viscosity modifiers and the like. (Adhesive film) The adhesive composition of the present invention, for example,
It can be used in the form of an adhesive film. At this time, the thickness of the film is usually in the range of 5 to 1,000 μm.

Although the adhesive film can be produced according to various production methods, it can be advantageously produced by applying the adhesive composition precursor of the present invention on a substrate and drying. As the application means, the same means as in the case of manufacturing an ordinary adhesive film can be used. Suitable application means are, for example, knife coaters, bar coaters, die coaters, extruders and the like. Drying conditions are not particularly limited, so that no residual solvent remains,
In order to prevent the curing reaction of the composition from unnecessarily proceeding during drying, drying is usually performed at a temperature of 60 to 100 ° C. for several seconds to 1 hour.

The substrate is not limited to those listed below, but may be a polyimide film, a plastic film such as polyester, or a metal foil such as copper foil or aluminum foil. In this case, it is usually used as an adhesive sheet or an adhesive tape composed of an adhesive film layer and a substrate. Also, use a release film for the substrate, remove all the release film when used,
The adhesive film alone can be used.

The adhesive film is laminated, for example, on an adherend, and is subjected to a thermocompression bonding operation including, for example, heating conditions at 100 to 180 ° C. for 0.1 to 2 minutes, and pressing conditions in a range of ^{2 to} 50 kg / cm ^2. To complete the adhesion. After completing the thermocompression operation,
Subsequently, a heating operation at 150 to 180 ° C. for 1 to 5 hours can be performed. During the thermocompression bonding operation, it is preferable to appropriately adjust the thickness of the adhesive film so that the composition component hardly flows out from the end face of the film. The thickness of the adhesive film is usually 10 to 2,000 μm
It is.

The cured adhesive film is, for example, 6
It is preferable to determine the composition of the adhesive composition so that the tensile storage modulus at 0 ° C. is 10 ¹⁰ dyn / cm ² or more. In this way, an adhesive film having high dynamic bending resistance at 60 ° C. and suitable as an adhesive for an FPC protective film that can be repeatedly bent can be obtained. In addition, FPC
As the adhesive for the protective film, it is preferable that the shrinkage ratio after the curing of the adhesive film is 0.1% or less. The shrinkage is the percentage of the dimensional reduction between before and after curing.

[0046]

EXAMPLES The present invention will now be described with reference to examples, but it should be understood that the present invention is not limited to the following examples. Further, “parts” in the examples are
Unless otherwise specified, it means "parts by weight". Example 1 (1) Preparation of Adhesive Composition Precursor (Dispersion) and Formation of Adhesive Film First, a phenoxy resin “trade name: manufactured by Toto Kasei Co., Ltd.”
60 parts of YP50S (number average molecular weight: 1,180, weight average molecular weight: 58,600), a bisphenol A type epoxy resin manufactured by Toto Kasei Co., Ltd. "trade name: YD128 (
15 parts of brominated epoxy resin “trade name: YDB400 (epoxy equivalent = about 400)” manufactured by Toto Kasei Co., Ltd., and 15 parts of dicyandiamide (Dicy) manufactured by ACR Corporation. Trade name: AMICURE CG1200 (amine equivalent = 21) "was dissolved in a mixed solvent of 80 parts of methyl ethyl ketone and 35 parts of methanol. A uniform first resin liquid was obtained.

Next, as the second resin liquid, Soken Chemical Co., Ltd.
Acrylic adhesive polymer solution "Trademark: SKDy"
ne, (product number) SK1309 ", and the first resin liquid was adjusted so that the solid content of the adhesive polymer was 9.6 parts with respect to the entire first resin liquid prepared as described above. This was added to obtain a base resin liquid in which the second resin liquid component was microscopically phase-separated and stably dispersed in the first resin liquid. The acrylic adhesive polymer of the second resin solution is an acrylic acid unit-containing copolymer, and ethyl acetate: toluene = 65:
It is available as a solution in 35 mixed solvents.
Further, the mother resin liquid prepared as described above was mixed with antimony pentoxide sol (trade name: Sun Colloid AME-130 manufactured by Nissan Chemical Industries, Ltd. (particle size = 5 to 50 nm, solid content concentration = 30% by weight). , Dispersion medium = methyl ethyl ketone "
20 parts were added. The adhesive composition precursor of this example was obtained as a uniform dispersion. The composition of the obtained adhesive composition precursor is summarized in Table 1 for reference, as shown in Table 1 below. Further, the ratio of methanol (MeOH) to methyl ethyl ketone (MEK) in the solvent contained in the adhesive composition precursor, MeOH / MEK
Was 0.37.

When the adhesive composition precursor of this example was evaluated with respect to its dispersion stability, it was shown that the formed micro phase separation was stably maintained and the dispersion stability was good.
The dispersed state was good enough that the original state could be easily restored only by shaking several times by hand even after 30 days. Subsequently, in order to form an adhesive film, the resulting dispersion was treated with one of the following plastic films: a PET film subjected to a release treatment, or a polyimide film manufactured by DuPont (trade name: Kapton V, (Thickness: 25 μm), and uniformly coated on a support film, and dried at 90 ° C. for 30 minutes. A support film, comprising the adhesive composition of this example provided on the support film, and having a thickness of 30 μm.
Thus, an “adhesive film with a support” was obtained, which was composed of an adhesive film having a thickness of m. (2) Evaluation of properties of adhesive film The properties of the obtained adhesive film were determined by the following items (A) to (A).
(G) was evaluated according to the procedure described.

A. Dynamic Viscoelasticity After preparing an adhesive film with a PET film as described above, the PET film was peeled off to obtain an adhesive composition (adhesive film alone). The adhesive film alone was sandwiched between two pieces of release paper, and the obtained laminate was
Thermocompression bonding at a pressure of 20 kg / cm ² for 1 minute at
Heat treatment was performed at 0 ° C. for 2 hours to cure the adhesive film. The cured adhesive film was separated from the two pieces of release paper to obtain a test piece. 100 ° C to 170 ° C of this test piece
The minimum shear modulus Gmin × 10 ⁻⁴ (dyn / cm ² ) was measured when the temperature was increased at a rate of 40 ° C./min. The device used for measuring the minimum shear modulus is a dynamic viscoelasticity measuring device manufactured by Rheometric Co., Ltd.
I "and the measurement frequency was 6.28 rad / sec.

B. The flow resistance of the adhesive during thermocompression bonding The adhesive film alone prepared in the same manner as in (A) above,
After forming a substantially circular through hole of 1 mm ² × 1 mm ² , a rolled copper foil having a thickness of 30 μm was laminated so as to cover the hole, and
Thermocompression bonding was performed at 0 ° C. for 1 minute at a pressure of 38 kg / cm ² . At this time, the amount (length) of the adhesive composition protruding from the edge of the hole into the hole was measured using an optical microscope, and the flow resistance (unit: mm) of the adhesive during thermocompression bonding was determined. It should be noted that the smaller the value is, the less the protrusion is, indicating that the flow resistance is good.

C. Dimensional stability After preparing the adhesive film with a polyimide film as described above, on the polyimide surface of the adhesive film,
A rectangular wound of about 70 mm × about 35 mm was made with a cutter knife, and the length of the long side was measured. Thereafter, a “Kapton V (trade name, as described above)” film was laminated on the adhesive surface of the adhesive film at a temperature of 120 ° C. for 1 minute at a pressure of 10 mm.
The sample was thermocompression-bonded at kg / cm ² , followed by heat treatment at 170 ° C. for 2 hours to obtain a test piece. The test specimen was further added at room temperature for one more time.
After leaving for a period of time, the length of the long side of the scratch on the previously attached test piece was measured again, and the percentage of the changed length with respect to the length before thermocompression bonding was defined as the dimensional change rate (%). When the dimensional change rate shows a negative value, it means that the test piece has shrunk.

D. Glass transition temperature (Tg) The tensile elastic modulus (E '+ E ") was measured in the same manner as in the above item (A) using a test piece obtained by post-curing the adhesive film alone at 150 ° C. for 3 hours, and measuring tan δ (= E "/ E ')
Is the glass transition temperature Tg (° C.). The measurement frequency was 6.28 rad / sec.

E. Laminate the solder heat-resistant adhesive film alone with a rolled copper foil having a thickness of 30 μm.
Thermocompression bonding at 20 ° C, 1 minute, pressure 20kg / cm ² , 150 ° C
The test piece was post-cured for / 3 hours. After the test piece was left on the molten solder at 260 ° C. for 1 minute, “Pass (passed the solder heat resistance test)” when there was no foaming, and “Failure” when foaming occurred.
(Failed solder heat test) ".

F. Rolled copper foil having a thickness of 30μm on the adhesive surface of the polyimide film with an adhesive film prepared as the adhesive force above the stack,
Thermocompression bonding was performed at 120 ° C. for 1 minute at a pressure of 20 kg / cm ² , followed by heat treatment at 170 ° C. for 2 hours to prepare a test piece. The copper foil of this test piece was peeled at an angle of 180 ° and a peeling speed of 5
Peeling was performed at 0 mm / min, and the integrated average of the obtained values was defined as the adhesive strength (peeling adhesive strength, g / cm).

G. Punching properties A 10 mm diameter through-hole was formed by punching with an office punch on the adhesive film with the polyimide film prepared as described above, and the periphery of the through-hole was observed with an optical microscope (magnification: 50 times). When cracks are observed,
(Fail), and otherwise (OK).

The evaluation results of the characteristics described in the above items (A) to (G) are summarized in Table 1 below. Further, the properties of the obtained adhesive film were evaluated for the following items. H. When the flame-retardant adhesive film alone was evaluated for flame retardancy in accordance with a method conforming to the UL94 standard, the adhesive film of this example satisfied level V0 and showed good flame retardancy.

I. Microphase-separated structure Each of the adhesive precursor composition and the adhesive film of this example was observed with an optical microscope at a magnification of 500 times, and in each case, the microstructure had a microphase-separated structure. It was found that the fine "island-like phase" having dimensions had a structure uniformly dispersed in the "sea-like phase (matrix)". Such a micro phase separation structure,
It is considered that the resulting adhesive film effectively contributes to the improvement of dimensional stability, impact resistance (punching property), and flow resistance during thermocompression bonding. Reference Example 1 and Reference Example 2 This example is a reference example implemented for comparison with Example 1.

The adhesive of this example was prepared in the same manner as in Example 1 except that the ethyl acetate / toluene mixed solvent of the second resin solution was changed to methyl ethyl ketone alone (Reference Example 1) and toluene alone (Reference Example 2). A composition precursor was prepared. The adhesive composition precursor of this example, when used immediately after preparation,
Although an adhesive film having the same performance as in Example 1 was provided, the storage stability was not good, and the same microphase separation structure as in Example 1 could be maintained for only several hours. Example 2 An adhesive composition precursor and an adhesive film of this example were prepared in the same manner as in Example 1 except that the type and content of the adhesive polymer were changed as shown in Table 1 below. . The adhesive polymer used in this example was obtained by reaction in an ethyl acetate solution by a solution polymerization method (prototype number EX01).
It was a copolymer of 2-methylbutyl acrylate and acrylic acid (weight ratio = 90: 10). In this example, the density is 3
A 0% by weight ethyl acetate solution was used as the second resin solution.

The adhesive composition precursor of this example had good dispersion stability, as in Example 1. In addition, the adhesive composition precursor and the adhesive film of this example had the same microphase separation structure as in Example 1. Further, the results of evaluation of the adhesive film of this example in the same manner as in Example 1 are shown in Table 1 below. Examples 3 to 14 In the same manner as in Example 1 except that the types and contents of the respective resin components were changed as shown in Table 1 below, the adhesive composition precursors and the adhesives of the respective examples were used. A film (adhesive composition) was prepared.

The adhesive composition precursor of each example had good dispersion stability, as in Example 1. In addition, the adhesive composition precursor and the adhesive film of each example had the same microphase separation structure as in Example 1. Further, the results of evaluation of the adhesive film of each example in the same manner as in Example 1 are shown in Table 1 below. The details of the resin component newly used in each example are as listed below. Polyester polyol-containing phenoxy resin PKHM30: Polyester polyol-containing phenoxy resin manufactured by Union Carbide Co., Ltd. “Product name: PKH
M-30 (containing about 30% by weight of polyester polyol) ". Adhesive polymer (second resin liquid) Example 3 and Example 4: Solution polymerized product (prototype number EX0
2), a copolymer of phenoxyethyl acrylate and acrylic acid (weight ratio = 99: 1).

Example 5 and Example 6: The same one as in Example 1 was used. Example 7: Solution polymerized product (prototype number EX03), copolymer of ethyl acrylate and acrylic acid (weight ratio = 90: 1)
0). Example 8: A copolymer containing a hydroxyl group in the molecule, (product number) SK1435 manufactured by Soken Chemical Co., Ltd. Ethyl acetate:
Available as a solution containing a mixed solvent of toluene (59:41).

Example 9: The same one as in Example 1 was used. Example 10: A solution polymerized product (prototype number EX04), a copolymer of butyl acrylate and 4-methacryloyloxyethyl trimellitic anhydride (weight ratio = 90: 10). Example 11: Solution-polymerized product (prototype number EX05), copolymer of butyl acrylate and acetoacetoxyethyl methacrylate (weight ratio = 80: 20).

Example 12: Solution-polymerized product (prototype number EX0
6), a copolymer of 2-ethylhexyl acrylate and phenoxyethyl acrylate (weight ratio = 80: 20). Example 13: A solution polymerized product (prototype number EX07), a copolymer of butyl acrylate and phenoxyethyl acrylate (weight ratio = 50: 50). Example 14: Solution-polymerized product (prototype number EX08), copolymer of butyl acrylate macromer and phenoxyethyl acrylate (weight ratio = 50: 50).

The solution-polymerized products of the trial production numbers EX02 to EX08 were obtained by reacting in an ethyl acetate solution by a solution polymerization method, and 30% by weight solutions thereof were used. Comparative Example 1 and Comparative Example 2 Except that the types and contents of the respective resin components were changed as shown in Table 1 below, the adhesive composition precursor and the adhesive were prepared in the same manner as in Example 1 described above. A film (adhesive composition) was prepared.

The results of evaluation of the adhesive film of each example in the same manner as in Example 1 are shown in Table 1 below. In addition, in these comparative examples, since the adhesive polymer was not used, the punching property was particularly inferior to Examples 1 to 14.

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[Table 1]

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As described above, according to the present invention, in the adhesive composition, dimensional stability particularly after heat treatment further performed after thermocompression bonding, especially impact resistance before completion of curing, flow resistance during thermocompression bonding. (E.g., prevention of large flow that may cause protrusion to the soldered portion), adhesiveness, and flame retardancy can be effectively enhanced, and thus the adhesive composition can be used for an FPC protective film. It can be used advantageously as an adhesive.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Akihito Muramatsu 3-8-8 Minamihashimoto, Sagamihara City, Kanagawa Prefecture F-term in Sumitomo 3M Limited (Reference) 4J004 AA02 AA10 AA11 AA13 AA17 AA18 AB05 CA06 CA08 CC02 FA04 FA05 4J040 DB062 DF042 EC001 EC061 EC062 EC071 EC072 EC151 EC152 EC341 EC342 EE061 EE062 HA136 HA306 HC18 JA09 JB09 KA03 KA16 KA26 LA02 LA06 LA08 MA02 MA10 MB03 NA20

Claims (3)

[Claims] 1. An adhesive composition containing a resin component containing a thermoplastic resin, an epoxy resin, and a curing agent, wherein the thermoplastic resin contains a tacky polymer, and the resin component further comprises: An adhesive composition comprising an inorganic colloid dispersed in the resin component. 2. The epoxy resin contains a brominated epoxy resin, the inorganic colloid is an antimony pentoxide colloid, and the total ratio of the brominated epoxy resin and the antimony pentoxide colloid is determined by the adhesive composition. The adhesive composition according to claim 1, wherein the amount is in the range of 13 to 60% by weight based on the total weight of the product. 3. An adhesive composition precursor that provides the adhesive composition according to claim 1 after drying, wherein the adhesive composition precursor comprises: (i) the resin component; and (ii) a dispersion medium. And an inorganic particle sol containing the inorganic colloid dispersed in a dispersion medium thereof, and an adhesive composition precursor.