JP2001348555A - Adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive having a high adhesive power, and excellent in preserving stability and moist heat resistance of the adhesive power. SOLUTION: This adhesive composition contains a polycarbodimide and a compound of general formula 1 (wherein, R1 to R3 are the same or different and >=1 of them are each an alkoxy and others are each an alkyl; R4, R7 are each the same or different alkylene; one of R5, R6 is H and another is an alkyl or an aromatic group; R8 to R10 are the same or different and >=1 of them are each an alkoxy and others are each an alkyl).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive composition comprising a polycarbodiimide compounded with a silane compound as an adhesion aid, and an adhesive sheet using the same. This adhesive composition has high adhesive strength to various adherends and shows excellent wet heat 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.

However, these adhesives have poor heat resistance, and become brittle when heated at a temperature of 300 ° C. or more, and lose their self-holding properties. In order to improve such heat resistance, JP-A-8-245941 discloses that polycarbodiimide is not a simple substance, but a copolymer of polyurethane and polyamide.
An adhesive having improved heat resistance and wettability is disclosed.

[0004] Further, there is a method using an additive (adhesion aid) for improving the adhesion. Such additives generally have insufficient compatibility with the polymer, cause turbidity and deteriorate in appearance, polar groups segregate on the surface, fail to obtain a desired adhesive strength, or have 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 was found that by blending a silane compound having a specific chemical structure with a polycarbodiimide resin having high heat resistance as an adhesion aid, an adhesive exhibiting excellent adhesion even under high temperature and high humidity can be obtained. As a result, the present invention has been completed. That is, the present invention relates to polycarbodiimide and the following formula (1):

[0006]

Embedded image (In the formula, at least one of R ₁ , R ₂ and R ₃ is an alkoxy group and the other is an alkyl group, which may be the same or different. R ₄ and R ₇ may be the same or different alkylene groups. .R ₅ and _{R 6} is is on the other hand at least one of hydrogen an alkyl group or an aromatic group _.R 8, R
_At least one of ₉ and R ₁₀ is an alkoxy group and the other is an alkyl group, which may be the same or different. The present invention relates to an adhesive composition containing the silane compound represented by the formula (1). Further, the present invention is an adhesive sheet comprising such a composition.

[0007]

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

(Polycarbodiimide) The polycarbodiimide used in the adhesive composition of the present invention is preferably an aromatic polycarbodiimide having high heat resistance. The polymerization degree n of the aromatic polycarbodiimide is 2 to 200, preferably 8 to 1.
00. 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 from 20 ° C. to 250 ° C., preferably from 30 ° C. to 20 ° C.
0 ° C. If the Tg is lower than this, handling is difficult. On the other hand, if the Tg is too high, a high temperature is required for adhesion, which is not preferable.

Accordingly, as preferred polycarbodiimides, specifically, aromatic polycarbodiimides represented by the following formulas (2) to (9) are preferable.

[0011]

Embedded image (In the formula, R ₁₁ is 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 conventional 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, and a chloroformate is allowed to act on the raw material to obtain a biscarbamate. May be used to obtain a polycarbodiimide by carrying out a reaction in the presence of a compound (JP-A-10-158394).
The obtained polycarbodiimide may be used as it is,
It may be used after being purified by an appropriate method.

(Silane compound) The silane compound is represented by the following formula (1)
It has a structure shown by.

[0015]

Embedded image In the above formula, at least one of R ₁ , R ₂ and R ₃ is an alkoxy group, and the other is an alkyl group. Examples of the alkoxy group include a methoxy group and an ethoxy group. Examples of the alkyl group include a linear alkyl group such as a methyl group, an ethyl group and a propyl group, and a branched alkyl group such as an isopropyl group. In addition, these R ₁ , R ₂ and R ₃ may be the same or different.

R ₄ and R ₇ are the same or different alkylene groups. Examples of the alkylene group include a methylene group, an ethylene group and a propylene group.

At least one of R ₅ and R ₆ is hydrogen and the other is an alkyl group or an aromatic group. Examples of such an alkyl group include a linear alkyl group such as a methyl group, an ethyl group and a propyl group, and a branched alkyl group such as an isopropyl group. Examples of the aromatic group include a phenyl group and a toluyl group. And the like.

At least one of R ₈ , R ₉ and R ₁₀ is an alkoxy group and the other is an alkyl group, which may be the same or different. The alkoxy group and the alkyl group may be the same as those described above for R ₁ , R ₂ and R ₃ .

As described above, the silane compound used in the present invention is a functional group having an active hydrogen having a high reaction with polycarbodiimide, such as a hydroxyl group, a carboxyl group,
It is necessary not to have an amino group or the like. Further, those having a functional group which is unstable with respect to moisture, such as an isocyanate group, are not preferred because they reduce the storage stability of the composition.

When producing the silane compound of the formula (1),
Conventionally known various methods may be used (for example, New Experimental Chemistry, Vol. 14, “Synthesis and Reaction of Organic Compounds III”, P1631).
32, edited by The Chemical Society of Japan, published by Maruzen Co., Ltd.), and can be produced by an addition reaction of the corresponding aminosilane and isocyanatesilane.

(Preparation of Composition) In the composition of the present invention, the silane compound is used in an amount of 0.01 to 30 parts by weight, more preferably 0.1 to 30 parts by weight, per 100 parts by weight of polycarbodiimide.
10 parts by weight. If the amount of the silane compound is larger than this, it may be difficult to achieve compatibility with the polycarbodiimide, or the moisture resistance and strength may be reduced. On the other hand, if the amount of the silane compound is less than this, the excellent effects of the present invention cannot be obtained, 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 a silane compound with polycarbodiimide.

Further, a polycarbodiimide having a structure different from that described above may be added to adjust the elastic modulus or reduce the cost. Also, if necessary for the purpose of adhesion, adjustment of thermal deformation or coloring, fillers such as silica fine powder, titanium white,
You may add a thickener, a leveling agent, etc.

(Sheet) To produce the adhesive sheet of the present invention, any of conventionally known methods (casting, spin coating, roll coating, etc.) may be used. For example, the adhesive composition can be applied to a stainless plate or a glass plate, dried, and then peeled off from the plate to produce an adhesive sheet.

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.

An adhesive layer comprising the adhesive composition of the present invention may be formed on a support to produce an adhesive sheet with a support having two or more layers. 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.

[0027] The support used for these may be a metal foil or an insulating film. 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, such as a metal foil / insulating film, obtained by laminating two or more layers may be used. Examples of such a two-layer substrate include a copper / polyimide two-layer substrate.

[0029] The adhesive sheet thus produced is thermally cured by a heat treatment to exhibit 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.

[0031]

Next, the present invention will be described more specifically with reference to examples and comparative examples. The synthesis was performed by nitrogen gas flow. N
-Phenyl-γ-aminopropyltrimethoxysilane,
γ-aminopropyltrimethoxysilane and γ-isocyanatopropyltriethoxysilane were obtained from Shin-Etsu Chemical Co., Ltd. The evaluation method is as follows.

[0032]IR  It measured using FT / IR-230 (made by JEOL).

[0033]Number average molecular weight  HLC8120 (manufactured by Tosoh Corporation) as an apparatus, and GMH
_HR-H+ GMH_{HR- H}+ G2000H_HR(East Corporation
Using tetrahydrofuran as a developing solvent
It was measured by polystyrene standard conversion.

[0034]Adhesive strength  A 1 mm thick glass cloth epoxy plate (F
R-4), 90 ° C x 30 min, then 150
It dried at 30 degreeC x30min. This is 2mm x 2mm x
Silicon chips diced to 750 μmt (passive
(Silicon nitride), and flip chip
Using a bonder (DB100 made by Shibuya Kogyo), 300 ° C x
The test pieces were obtained by bonding at 3 MPas × 40 sec. More
Coated on fluorine sheet instead of lath cloth epoxy plate
After drying under the same conditions, peel off from the fluorine sheet
To obtain an adhesive sheet. This adhesive sheet is
Place it on a oxy board and attach a silicon chip in the same way as above.
A test piece was obtained by bonding. Adhesion of chips to these specimens
Measures the adhesive strength of the adhesive with a commercially available push-pull gauge
did.

[0035]Pressure cooker (PCT) test  The test piece was tested at 121 ° C. × 100% RH × 2.1 atm.
Pressure cooker tester (TABAI Pressure cooker T
PC-411) was measured for adhesive strength after 72 hours.

[Preparation Example 1] (Preparation of silane compound) 25.5 g (0.1 mol) of N-phenyl-γ-aminopropyltrimethoxysilane was charged into a flask and γ-isocyanate was added at 65 ° C. while stirring with a magnetic stirrer. 27.7 g (0.1 mol) of propyltriethoxysilane
Was introduced. The mixture was stirred for 3 hours. IR of the product,
The following compound A was found to be 95 by NMR and GPC analysis.
It was confirmed that the product was produced in a% yield.

[0037]

Embedded image

[Production Examples 2 and 3] (Production of silane compound) In Production Example 1, 17.9 g of γ-aminopropyltrimethoxysilane was used instead of N-phenyl-γ-aminopropyltrimethoxysilane, (0.1 mmol ) Or γ-
22.1 g of aminopropyltriethoxysilane, (0.1
The following compound B and compound C were obtained in a yield of 96 and 98%, respectively, in the same manner as in Production Example 1 except that (mmol) was used.

[0039]

Embedded image

[Production Example 4] (Production of polycarbodiimide) 2,2-dimethyl-1,3-bis (4-
Aminophenoxy) propane (manufactured by Wakayama Seika Kogyo Co., Ltd.) was subjected to isocyanation to obtain 2,2-dimethyl-1,3-bis (4-isocyanatophenoxy) propane.

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. That is, the following formula:

[0042]

Embedded image It was confirmed to be a carbodiimide represented by. The number average molecular weight of the varnish was Mn = 1860 (n = 6).

Example 1 The polycarbodiimide (P1) varnish obtained in Production Example 4 and the silane compound A synthesized in Production Example 1 were mixed with a polycarbodiimide solid content: silane compound = 10
0: 1 (weight ratio). Good compatibility was shown without phase separation. A glass cloth epoxy plate with an adhesive was prepared using this composition. A chip was bonded on this glass cloth epoxy plate under the preceding conditions, and the shear adhesive strength between the initial stage and 72 hours after PCT was measured.

[Examples 2 and 3] Test pieces were obtained in the same manner as in Example 1 except that silane compound B or silane compound C was used instead of silane compound A.

[Examples 4 and 5] In Example 1, instead of using a glass cloth epoxy plate with an adhesive, it was coated on a fluorine sheet, dried under the same conditions as in Example 1, and peeled from the fluorine sheet. A test piece was obtained in the same manner as in Example 1 except that the chip was bonded to a glass cloth epoxy plate using the obtained adhesive sheet.

[Comparative Example 1] A test piece was obtained in the same manner as in Example 1 except that a glass epoxy plate with an adhesive was prepared using only polycarbodiimide varnish without using an adhesion aid.

Comparative Example 2 The polycarbodiimide varnish (P1) of Production Example 4 and γ-aminopropyltriethoxysilane were mixed at a solid content of 100: 1 parts by weight, and gelled within 30 minutes. Table 1 shows the measurement results of the shear adhesive strength using the test pieces obtained in Examples 1 to 5 and Comparative Example 1.

[0048]

[Table 1]

[0049]

The adhesive comprising the resin composition of the present invention is
It has high adhesive strength to the adherend, and is excellent in storage stability and 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.

Claims (4)

[Claims] 1. Polycarbodiimide and the following formula (1): (In the formula, at least one of R ₁ , R ₂ and R ₃ is an alkoxy group and the other is an alkyl group, which may be the same or different. R ₄ and R ₇ may be the same or different alkylene groups. .R ₅ and _{R 6} is is on the other hand at least one of hydrogen an alkyl group or an aromatic group _.R 8, R
_At least one of ₉ and R ₁₀ is an alkoxy group and the other is an alkyl group, which may be the same or different. An adhesive composition comprising a silane compound represented by the formula: 2. The adhesive composition according to claim 1, wherein the polycarbodiimide is an aromatic polycarbodiimide. 3. An adhesive sheet comprising the resin composition according to claim 1. 4. An adhesive sheet with a support, wherein the adhesive composition according to claim 1 is used for an adhesive layer.