JP2001192639A - Adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive composition having high adhesive strength to an adherend and also excellent in preservation stability and resistance of adhesive strength to moist heat. SOLUTION: This adhesive composition comprises both of polycarbodiimide and an amide compound containing siloxane bond.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an adhesive composition containing a polycarbodiimide and a specific amide compound, and an adhesive sheet using the same. This adhesive composition exhibits high adhesive strength to various adherends and exhibits excellent heat and moisture resistance.

[0002]

2. Description of the Related Art Conventionally, various adhesives containing polycarbodiimide as a main component have been known. For example, JP-A-10-6
No. 7978, JP-A-10-326952 and the like describe a polycarbodiimide adhesive having high heat resistance and excellent solder heat resistance. In addition, Japanese Patent Application Laid-Open No. H08-1488
No. 38 discloses an adhesive for electronic materials mainly containing an aromatic polycarbodiimide obtained by using diphenylmethane diisocyanate or tolylene diisocyanate as a monomer.

[0003] However, these adhesives have poor heat resistance, and have the disadvantage that they become brittle when heated at a temperature of 300 ° C or higher and lose their self-holding properties. In order to improve such heat resistance, JP-A-8-245941 discloses an adhesive having improved heat resistance and wettability by using a copolymer with polyurethane or polyamide instead of polycarbodiimide alone.

[0004] Further, there is a method using an additive (adhesion aid) for improving the adhesion. Such an adhesive generally has insufficient compatibility with a polymer, causes turbidity and deteriorates appearance, polar groups are segregated on the surface, and a desired adhesive force cannot be obtained, or has a functional group. In the case of an additive, there is a problem that a reaction with a polymer occurs to form a gel.

[0005]

SUMMARY OF THE INVENTION The present inventors have conducted intensive studies to obtain an adhesive composition having high wettability, exhibiting high adhesive strength to various adherends, and having excellent wet heat resistance. went. As a result, it has been found that by blending a siloxane-modified amide compound with a polycarbodiimide resin having high heat resistance as an adhesion aid, excellent adhesion can be obtained even under high temperature and high humidity, and the present invention has been completed. Reached.

That is, the present invention is an adhesive composition containing a polycarbodiimide and an amide compound containing a siloxane bond. Here, the amide compound is preferably an amide compound represented by the following formula (1a), particularly preferably an amide compound represented by the following formula (1b).

[0007]

Embedded image Wherein R ¹ is an alkyl group or a phenyl group, R ² is a lower alkyl, a lower alkoxy or a phenyl;
Represents an integer of 1 to 6. )

Embedded image (In the formula, R ¹ is the same as above, and Me is a methyl group.)

[0008]

Next, the present invention will be described in more detail.

(Polycarbodiimide) The polycarbodiimide constituting the adhesive composition of the present invention is preferably an aromatic polycarbodiimide having high heat resistance. Further, the polycarbodiimide preferably has two or more benzene rings in the repeating unit. Degree of polymerization n of aromatic polycarbodiimide
Is 2 to 200, preferably 8 to 100. When n is smaller than 2, the reliability of the film is poor, which is not preferable. On the other hand, if the degree of polymerization n exceeds 200, the varnish is easily gelled in a short time, which is not preferable.

The glass transition temperature (Tg) of the aromatic polycarbodiimide is 30 to 250 ° C., preferably 90 to 200 ° C.
It is. If Tg is lower than this, it is difficult to handle,
On the other hand, if it is too high, a high temperature is required for adhesion, which is not preferable.

Accordingly, specific examples of preferred polycarbodiimides include those represented by the following formulas (2) to (8).

[0012]

Embedded image (In the formula, R ⁴ represents a linear or branched alkylene group having 3 to 10 carbon atoms, and n represents an integer of 2 to 200.)

Such a polycarbodiimide can be obtained by subjecting a corresponding aromatic diisocyanate to decarboxylation by a known method in the presence of a known phosphoric acid catalyst, for example, a phosphorene oxide.

As another method for producing polycarbodiimide, an aromatic diamine is used as a raw material, a biscarbamate is synthesized by reacting with chloroformate, and then a carbodiimidation catalyst, an organic silicon halide compound and a basic compound are used. May be used to obtain a polycarbodiimide by carrying out a reaction in the presence of a compound (see JP-A-10-158394).
issue).

The obtained polycarbodiimide may be used as it is, or may be purified by an appropriate method before use.

(Amide Compound) The amide compound used in the adhesive composition of the present invention has a siloxane bond in the molecular structure. As such an amide compound, an amide compound represented by the following formula (1a) is preferable,

Embedded image Wherein R ¹ is an alkyl group or a phenyl group, R ² is a lower alkyl, a lower alkoxy or a phenyl;
Represents an integer of 1 to 6. In particular, an amide compound represented by the following formula (1b) is preferable.

[0017]

Embedded image (In the formula, R ¹ is an alkyl group or a phenyl group.) Examples of the alkyl group of R ¹ include a linear or branched alkyl group having 1 to 20 carbon atoms, such as methyl,
Ethyl, isopropyl, n-propyl, n-butyl, t
-Butyl, dodecyl, heptadecyl and the like.
R ² is a lower alkyl group such as methyl, a lower alkoxy group such as methoxy or ethoxy, or a phenyl group. n is an integer of 1 to 6, preferably n is 3.

To produce the amide compound of the formula (1a), the following formula (9)

Embedded image (Wherein R ² and n are the same as described above) by the following formula (10)

Embedded image (Wherein R ¹ is the same as described above), and an amide compound is obtained by reacting with an acid chloride represented by a method known per se. Such a reaction is typically performed in an aromatic solvent such as toluene using triethylamine or the like at room temperature for 10 minutes to 1 hour.

(Preparation of composition) In the composition of the present invention, the compounding ratio of the amide compound is preferably 0.01 to 30 parts by weight, more preferably 0.1 to 10 parts by weight, per 100 parts by weight of polycarbodiimide. . If the compounding amount exceeds this range, compatibility may become difficult, and the moisture resistance and strength of the film may be reduced. On the other hand, if the amount is less than this range,
The excellent properties of the amide compound cannot be exhibited, and sufficient adhesive strength cannot be obtained.

The adhesive composition of the present invention can achieve good adhesiveness and heat resistance simultaneously only by mixing an amide compound with the polycarbodiimide, and is extremely valuable in industry.

The adhesive composition of the present invention may further contain a polycarbodiimide having a structure different from that described above in order to adjust the elastic modulus and reduce the cost. Also, silica fine powder, if necessary for the purpose of adhesion, thermal deformation control or coloring,
A filler such as titanium white, a thickener, a leveling agent, and the like may be added.

(Sheet) In order to produce the adhesive sheet of the present invention, any conventionally known method (casting, spin coating, roll coating, etc.) may be used. For example, a method in which the adhesive composition is applied to a stainless steel plate or a glass plate, dried, and then peeled off from the plate to produce an adhesive film can be adopted.

A molded product obtained by molding the composition of the present invention into a film can be used as a heat-resistant adhesive sheet.
The thickness of a sheet that can be formed into a film or an adhesive sheet is generally 1 to 200 μm, but is not limited to this and can be appropriately selected depending on the purpose.

Further, an adhesive layer comprising the adhesive composition of the present invention may be formed on a support to produce an adhesive sheet having a two-layer structure. In order to produce an adhesive sheet having such a structure, a varnish containing the adhesive composition of the present invention may be applied on a support and dried, and the adhesive film produced by the above method may be pressed by a press or the like. It may be manufactured by laminating on a support.

Examples of the support used for these include metal foils and insulating films. As the metal foil, any of aluminum, copper, silver, gold, nickel, indium, chromium, lead, tin, zinc, palladium and the like may be used, and these may be used alone or as an alloy. As the insulating film, any film having heat resistance or chemical resistance, such as polyimide, polyester, or polyethylene terephthalate, can be used.

The metal foil and the insulating film may be used singly, or a two-layer base material obtained by laminating two or more layers, such as a metal foil / insulating film, may be used. Examples of such a two-layer substrate include a copper / polyimide two-layer substrate.

The adhesive sheet produced in this way is hardened by heat treatment and exhibits a strong adhesive force. In order to perform the heat treatment, an appropriate method such as a heater, ultrasonic waves, or ultraviolet light can be used.

The adhesive composition of the present invention can be used not only on a plastic surface but also on an adherend containing silicon, which is generally difficult to adhere, such as glass, ceramic, or silicon wafer, to a -Si-O-Si-bond or -bond. It is highly effective in improving the adhesive strength to a substrate having a Si-N- bond, and is useful as an adhesive for electronic materials.

[0029]

Next, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples. The synthesis was performed under a nitrogen stream. 1,3
-Bis (3-aminopropyl) tetramethyldisiloxane was obtained from Shin-Etsu Chemical Co., Ltd., and acetyl chloride, benzoyl chloride and heptadecanoyl chloride were obtained from Wako Pure Chemical Industries, Ltd. The evaluation method is as follows.

[0030]IR  It measured using FT / IR-230 (made by JEOL).Number average molecular weight  HLC8120 (manufactured by Tosoh Corporation) as an apparatus, and G
MH_HR-H+ GMH _HR-H+ G2000H
_HR(Tosoh Corporation) to develop tetrahydrofuran
Measured in terms of polystyrene standard as solvent
Was.

[0031]Adhesive strength  The adhesive composition was applied to a 36 μm copper foil, and 90
At 30 ° C x 30min, then at 250 ° C x 30min
Thus, an adhesive sheet having a two-layer structure of copper foil / resin was prepared. this
Is cut into 1.5 × 3 cm, and 10 mm × 10 mm × 52
Silicon chip diced to 0 μm (passive
: Flip chip bonder (Shibuya Kogyo)
260-320 ° C x 0.33 kg
f / mm²Bonding was performed for 60 seconds. Shimadzu Autograph A
180 degree peel strength was measured using GS-50D.Pressure cooker test (PCT)  Adhesive sheet and adherend are adhered, 121 ° C x 100% RH
× 2atm pressure cooker tester (TABAI Pres
Adhesion after 96 hours in sure cooker TPC-411)
Was measured.

[Preparation Example 1] (Synthesis of amide compound A)
2.49 g (10 mmol) of 1,3-bis (3-aminopropyl) tetramethyldisiloxane, 1.57 of acetyl chloride
g (20 mmol) and 2.02 g (20 mmol) of triethylamine were added, and the mixture was stirred at room temperature for 30 minutes. The generated triethylamine hydrochloride was removed by filtration. The filtrate was stirred with water, reprecipitated with n-heptane, dried under reduced pressure, and dried.
The formation of an amide compound was confirmed by R (FIG. 1). The yield is 9
2%.

[Production Example 2] (Synthesis of amide compound B)
g, 1.49 g (10 mmol) of 1,3-bis (3-aminopropyl) tetramethyldisiloxane, 2.81 g (20 mmol) of benzoyl chloride, and 2.02 g (20 mmo) of triethylamine
l) was added and stirred at room temperature for 30 minutes. The generated triethylamine hydrochloride was removed by filtration. The filtrate was stirred with water, reprecipitated with n-heptane, dried under reduced pressure, and the formation of an amide compound was confirmed by IR (FIG. 2).
The yield was 90%.

[Production Example 3] (Synthesis of amide compound C) Toluene 20.0 was placed in a flask.
g, 1,3-bis (3-aminopropyl) tetramethyldisiloxane 2.49 g (10 mmol), stearoyl chloride 6.06 g (20 mmol), triethylamine 2.02 g (20 m
mol) and stirred at room temperature for 30 minutes. The generated triethylamine hydrochloride was removed by filtration. The filtrate was stirred with water, reprecipitated with n-heptane, dried under reduced pressure, and the formation of an amide compound was confirmed by IR (FIG. 3). The yield was 93%.

[Production Example 4] (Synthesis of polycarbodiimide (P1))

[0036]

Embedded image Polycarbodiimide P1 According to the phosgene method, 2,2-dimethyl-1,3-bis (4-
Aminophenoxy) propane (obtained from Wakayama Seika Kogyo)
Of 2,2-dimethyl-1,3-
Bis (4-isocyanatophenoxy) propane was obtained.

The above diisocyanate (37.6) was added to the flask.
g, 111.1 mmol), 52.3 g of an aromatic hydrocarbon mixed solvent,
Carbodiimidization catalyst (3-methyl-1-phenyl-2
-Phosphoren-1-oxide) (1.07 g, 5.6 mmol), 1
-Naphthyl isocyanate (8.65 g, 53.7 mmol) was charged, and the mixture was stirred at 80 ° C for 2 hours to perform polymerization. Carbodiimidization was confirmed by IR spectrum (FIG. 4). The number average molecular weight of the varnish was Mn = 1860 (n = 6).

Example 1 The polycarbodiimide (P1) varnish synthesized in Production Example 4 and the compounds A, B and C synthesized in Production Examples 1, 2 and 3 were combined with polycarbodiimide solids:
The amide compound (adhesion aid) was blended at a weight ratio of 100: 1. All showed good compatibility without phase separation. An adhesive sheet was produced using these compositions.

Table 1 summarizes the results of measuring the adhesive strength between the adhesive sheet and the chip.

[0040]

[Table 1] Comparative Example 1 The varnish of P1 obtained in Production Example 4 and γ-aminopropyltriethoxysilane were mixed at a solid content of 100: 1 parts by weight, and gelled within 30 minutes.

[0041]

The adhesive sheet using the resin composition of the present invention as an adhesive layer has high adhesive strength to an adherend, excellent storage stability, and excellent wet heat resistance of adhesive strength. The adhesive material containing the adhesive composition of the present invention as a main component is preferable for fixing electronic parts and the like.

[Brief description of the drawings]

FIG. 1 is an infrared absorption spectrum of an amide compound A.

FIG. 2 is an infrared absorption spectrum of an amide compound B.

FIG. 3 is an infrared absorption spectrum of an amide compound C.

FIG. 4 is an infrared absorption spectrum of P1 of polycarbodiimide.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Michio Satsuma, Inventor 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Inventor Shu Mochizuki 1-2-1, Shimohozumi, Ibaraki-shi, Osaka F-term in Nitto Denko Corporation (reference) 4J004 AA11 AA17 AB05 BA02 CA06 CA08 CC02 CC03 FA05 4J040 EH001 GA03 GA08 GA25 HD36 JA09 JB02 KA31 LA01 LA02 LA06 LA07 LA08 MA01 MB05 NA20

Claims (7)

[Claims] 1. An adhesive composition comprising a polycarbodiimide and an amide compound containing a siloxane bond. 2. The adhesive composition according to claim 1, wherein the amide compound is represented by the following formula (1a). Embedded image Wherein R ¹ is an alkyl group or a phenyl group, R ² is a lower alkyl, a lower alkoxy or a phenyl;
Represents an integer of 1 to 6. ) 3. The adhesive composition according to claim 2, wherein R ² is methyl and n is 3. 4. The adhesive composition according to claim 1, wherein the polycarbodiimide is an aromatic polycarbodiimide. 5. The adhesive composition according to claim 1, wherein the polycarbodiimide is a polycarbodiimide having two or more benzene rings in a repeating unit. 6. A sheet-like adhesive composition comprising the composition according to claim 1. 7. An adhesive composition for a semiconductor wafer, comprising the composition according to claim 1.