JPS58118825A - Production of polyimide precursor - Google Patents

Abstract

PURPOSE:To obtain a polyimide precursor excellent in adhesion to glass, etc., moisture resistance, etc., by prereacting part of a tetracarboxylic acid component with an aminosilane and then polymerizing the prereaction product together with the remaining acid component with a diamine. CONSTITUTION:A silane-modified polycarboxylic acid component of formula II (wherein Rc1 and Tc2 are monovalent and bivalent residues of an organic tetracarboxylic acid component, respectively, Z is an acidic group and n is 2-3) is prepared by prereacting part of an organic tetracarboxylic acid component (e.g., pyromellitic dianhydride) with an aminosilane compound of formulaI(wherein R1 is an aromatic monovalent organic group, R2 is a bivalent organic group, m is 1-2, X is an alkoxy or the like and Y is an alkyl or the like) through the sec. amino and X groups in formulaI. Then, the purpose polyimide precursor is obtained by polymerizing this component together with the remaining organic tetracarboxylic acid component with a diamine.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a polyimide precursor by a polymerization reaction between an organic tetracarboxylic acid component and a diamine. More specifically, the present invention relates to a method for producing a polyimide polymer precursor that has good adhesion to adherends such as glass, ceramics, and silicon wafers, and has improved moisture resistance.

Conventionally, surface protection coatings have been used, as typified by applications such as element surface protection paints for semiconductor devices, bonding adhesives (binders), cloth impregnation materials, organic films for liquid crystal alignment, and soft error prevention shield films for integrated circuits. Si or S
When a polyimide film is provided on the bonded interface of i-0-5i, the adhesion with the polyimide polymer is poor.
Adhesion was improved by treating the interface with -5i with a coupling agent, or by introducing alkoxy groups or siloxane groups into the polyimide polymer [7].

In addition, the inventors previously proposed the general formula (3); (however,
In the formula, R2 is a divalent organic group containing a carbon atom directly bonded to a silicon atom, X is a hydrolyzable group selected from an alkoxy group, an acetoxy group, a phenoxy group, and a halogen;
is a group selected from an alkyl group, an alkoxy group, an acetoxy group, a phenoxy group, a silyl group, a siloxy group, a disilanyl group, an organosilyl group, an organosiloxy group, an organohalosilyl group, and an organohalosiloxy group) A part of the organic tetracarboxylic acid component is added to the aminosilane compound by adding an amine group (NH
2) via at least one hydrolyzable group (5) to form an acid group of the following general formula (4), where Z may contain an X group bonded to a carbonyl carbon; ~X and Y are the same as in the general system (3) above, and n is an integer of 2 or 3 when Y is an alkoxy group, acetoxy group, or phenoxy group, and from 2 to 3 when Y is a group other than the above. We proposed a method for producing a polyimide precursor in which a silane-modified polycarboxylic acid component represented by the following integer is used, and this carboxylic acid component is polymerized with a diamine together with the remaining organic tetracarboxylic acid component.

However, the polyimide polymer produced by this method has poor initial adhesion and pressure Kutzker test (12
Although it showed excellent adhesion at 1°C and 2 atm (hereinafter abbreviated as PCT), a problem arose in that the initial adhesive strength retention properties gradually deteriorated under high temperature conditions. . This was found to be a lack of equipment reliability in the current situation where moisture resistance is increasingly required year by year.As a result, the inventors conducted further studies to overcome this problem, and found that This invention has been achieved.

That is, the following general formula (1) has a structure in which H of the amine group is substituted with a monovalent organic group containing a hydrophobic aromatic ring instead of the aminosilanized metal represented by the general formula (3); (However, R1 is a monovalent organic group containing an aromatic ring, m is 1
or an integer of 2, R1, X and Y are the same as in the case of general formula (3)). Through one hydrolyzable group (X), a part of the organic tetracarboxylic acid component is reacted to form the following general formula (2) (however, each symbol in the formula is -, general formula (1)). , (same as in the case of 31, (4)), and this carboxylic acid component is polymerized with a diamine together with the remaining organic tetracarboxylic acid component to form a polyimide precursor. It is something to do.

In such a polyimide precursor, a monovalent organic group ('t) containing an aromatic ring in the general formula (1) is bonded pendantly to the polymer chain in the aminosilane-modified portion of the general formula (1). However, this substituent effect and the above organic group (R1
) is bulky, which makes it hydrophobic to water, and the polyimide polymer formed by ring-closing condensation of this precursor polymer also becomes hydrophobic, significantly improving its adhesion to adherends. It is something to do.

As described above, according to the present invention, since the aminosilane compound can be directly introduced into the polymer chain as in the above-mentioned proposal, the polyimide film can be applied after previously treating the adherend with a coupling agent or the like, as in the conventional method. It is possible to improve adhesion by performing surface treatments such as formation and maintaining adhesive strength. As a result of this bonding, the adhesion between the adherend and the polymer film is improved, thereby significantly improving the initial adhesion retention characteristics under high temperature and high humidity conditions.

In addition, in this invention, the above-mentioned improvement in adhesion can be designed with the necessary minimum modification amount of the aminosilane compound used for modification, and therefore, the moisture resistance of the polyimide polymer itself is reduced due to the introduction of the aminosilane compound. No worries at all.

Moreover, when it is finally converted into polyimide through high-temperature heat treatment, it exhibits excellent adhesion and adhesive strength, as well as the excellent heat resistance, chemical resistance, electrical insulation, and mechanical properties inherent to polyimide. There is no particular need to further blend an unmodified ordinary polyimide precursor into the above-mentioned modified precursor. In other words, a polyimide precursor that exhibits the above-mentioned excellent properties by a simple operation of simultaneously polymerizing various silane-modified polycarboxylic acid components represented by the general formula (2) and a normal organic tetracarboxylic acid component with a diamine. It is extremely advantageous in the manufacturing process because it can produce
Further, homogenization of polyimide is also achieved.

The organic tetracarboxylic acid component used in this invention has two pairs of one-to-two acid groups bonded to adjacent carbon atoms, that is, two pairs of acid groups on the planned side, and is aromatic. A wide range of aromatic, aliphatic or alicyclic tetracarboxylic acids or derivatives thereof such as esters, amides, halides, -anhydrides and dianhydrides are included. The most preferred organic tetracarboxylic acid component is aromatic tetracarboxylic dianhydride. These acid components may be used alone or in combination of two or more.

Although there is no need to list specific examples of such organic tetracarboxylic acid components, representative examples of aromatic organic tetracarboxylic dianhydrides that are considered suitable include, for example, pyromellitic dianhydride. , 3・3′・4
・4'-benzophenone tetracarboxylic dianhydride, 3
・3',4,4'-biphenyltetracarboxylic dianhydride, 2,3,3,4-biphenyltetracarboxylic dianhydride, 2,3,6,7-7talentetracarboxylic dianhydride , 1,2,5,6-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 2,2-bis(3,4-dicarboxyphenyl)furopanihydride , bis(3,4-dicarboxyphenyl)sulfone dianhydride, 3,4,9,lO-perylenetetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)ether dianhydride, 2,2-hyperylenetetracarboxylic dianhydride, *
(2,3-dicarboxyphenyl)propanihydride,
1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride, 1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride, benzene-1,2,3,4-tetracarboxylic acid dianhydride Examples include anhydride, 2,3,6,7-anthracenetetracarboxylic dianhydride, 1,2,7,8-7 enanthrenetetracarboxylic dianhydride, and the like.

The silane-modified polycarboxylic acid component represented by the general formula (2) used in this invention is obtained by adding a part of the above-mentioned organic tetracarboxylic acid component to the following general formula (1): R, -NH ball. Panic Si→x)2 ・・River・・Mountain・・
...(1)■ (However, in the formula, 1 is a monovalent organic group containing an aromatic ring, R
2 is a divalent organic group containing a carbon atom directly bonded to a silicon atom; m is an integer of 1 or 2; Aminosilane represented by a group selected from alkyl group, alkoxy group, acetoxy group, phenoxy group, silyl group, siloxy group, disilanyl group, organosilyl group, organosiloxy group, organohalosilyl group and organohalosiloxy group) It is modified with a compound.

Typical examples of the above aminosilane compounds include those represented by the following molecular formula; Of course, it can be widely used as long as it satisfies general formula (1) other than the above. However, particularly preferred is one in which m in the general formula (1) is 2, that is, one having a divalent organic group (R2) containing a carbon atom directly bonded to a silicon atom. Note that R2 may include not only the upper alkylene group but also an aromatic ring.

The modification reaction is a reaction between an imino group, that is, a secondary amine 7 group (NH) and at least one hydrolyzable group (X) in general formula (1), and an organic tetracarboxylic acid component,
In order to accomplish this reaction, approximately 2 to 3 moles of the organic tetracarboxylic acid component are used per mole of the aminosilane compound.

The reaction usually proceeds exothermically, but it is usually controlled to below 30°C while cooling the reaction vessel using a water bath in the presence of a polar solvent such as N-methyl-2-pyrrolidone or N-N'-dimethylacetamide. The reaction may be continued until the reaction system becomes uniform and transparent.

As a specific example of the silane-modified polycarboxylic acid component obtained by this method, the structural formula of an example using an organic tetracarboxylic acid component is as follows. In the following Structural Formula (1), () "white" means each structural part represented by General Formula (2).

/---Regarding the above structural formula (1), in order to set n to 3, approximately 3 moles of pyromellitic dianhydride should be used per 1 mole of the aminosilane compound (and n = 2, it is sufficient to use approximately 2 moles of pyromellitic dianhydride per 1 mole of the aminosilane compound.And depending on the number of moles of pyromellitic dianhydride used, nζ2 and n
In some cases, the composition may be a mixture of 3 and 3, but in the present invention, such a mixed state may be used.

On the other hand, the above example uses an aminosilane compound in which Y in the general formula (1) is an alkoxy group, but aminosilanes in which Y is an alkoxy group or other group other than an acetoxy group or a phenoxy group are used. When using the compound, the number of moles of the organic tetracarboxylic acid component used per 1 mole of the aminosilane compound is approximately 2 moles, and a silane-modified polycarboxylic acid component such that n in general formula (2) is 2 is produced. Must. This has the effect of significantly improving the adhesion to glass etc. when made into a polyimide polymer by leaving at least one alkoxy group, acetoxy group, halogen or phenoxy group directly bonded to a silicon atom in the modified carboxylic acid component. Because you can get it.

Furthermore, when a dianhydride is used as the organic tetracarboxylic acid component as in the above example, the X group (CH30 group in this example) that bonds to the carbonyl carbon to the Z structural part in general formula (2) by an exchange reaction. will be included. On the other hand, when an organic tetracarboxylic acid component other than dianhydride is used, for example, one containing four free carboxyl groups, or one in which some or all of them are esterified, amidated or halogenated, etc. The Z structural part in general formula (2) is usually composed of the above-mentioned acid group itself, and in some cases, the structure is similar to that of the dianhydride, in which this acid group and the X group that has undergone an elimination reaction are reactively bonded. Sometimes it is said that Furthermore, in each of these embodiments, when the two structural moieties become acid groups other than free carboxyl groups, if some moisture is present in the system, they may be finally converted to carboxyl groups.

In the present invention, a polyimide precursor is produced by polymerizing the silane-modified polycarboxylic acid component thus produced and the remaining unmodified organic tetracarboxylic acid component simultaneously with diamine. Here, the ratio of the acid component to the diamine is preferably such that the diamine is equivalent to the total amount of the silane-modified polycarboxylic acid component and the unmodified organic tetracarboxylic acid component. However, in the case of an enemy attack, it is also possible to set the proportion so that the acid component represented by the above-mentioned total amount is excessive.

In addition, the usage ratio of the silane-modified polycarboxylic acid component, which is one of the acid components, is the aminosilane compound used in the synthesis of this acid component, the organic tetracarboxylic acid component used in the above synthesis, and the unmodified organic tetracarboxylic acid component. The amount of the aminosilane compound is 0.05 to 10 mol, particularly preferably 0.3 mol, relative to the total number of moles of the raw materials used consisting of and diamine.
What is necessary is just to set it to 2.0 mol%. According to the present invention, even if the amount of the aminosilane compound is reduced as mentioned above, a sufficiently satisfactory effect of improving adhesion to glass etc. can be obtained. On the other hand, if the amount exceeds the above, it is undesirable because the polyimide film finally formed may have poor film properties (tensile strength and toughness when formed into a film) and electrical properties such as dielectric strength voltage. In other words, on the film of unmodified polyimide skeleton,
This is because a silane-modified polycarboxylic acid component represented by formula (2), which has poor mechanical properties, is introduced.

As the diamine used in the polymerization reaction, aromatic diamine, aliphatic diamine, and alicyclic diamine can all be used. In order to exhibit better heat resistance, it is preferable to use aromatic diamines. These diamines may be used alone or in combination of two or more.

Although there is no need to list specific examples of such diamines, typical examples of aromatic diamines that are considered suitable include meta-phenylene diamine, para-phenylene diamine, 4,4'-diaminodiphenylmethane, and 4,4'-diaminodiphenylmethane. 4'-diaminodiphenyl ether, 2.
2'-bis(4-aminophenyl)propane, 3.3'
- Diaminodiphenylsulfone, 4,4-diaminodiphenylsulfone, 4,4-diaminodiphenylsulfide, benzidine, benzidine-3,3'-dicarboxylic acid, benzidine-3,3-disulfonic acid, benzidine-3
-monocarboxylic acid, benzidine-3-monosulfonic acid,
3,3'-dimethoxy-benzidine, para-bis(4-
Examples include aminophenoxy)benzene, meta-bis(4-aminophenoxy)benzene, metaxylylenediamine, and paraxylylenediamine.

The polymerization reaction may be carried out according to a conventionally known method, and is generally carried out in the presence of an organic solvent while controlling the temperature at 60°C or lower, preferably 30°C or lower, until a high degree of polymerization is obtained. Just let it happen. This degree of polymerization can be easily detected by examining the intrinsic viscosity [η] of the reactant.

Examples of organic solvents include highly polar basics such as N-methyl-2-pyrrolidone, N,N'-dimethylacetamide, N,r1/-dimethylformamide, N-N'-dimethylsulfoxide, and hexamethylphosphoramide. A solvent is used. All of these types of solvents are highly hygroscopic, and absorbed moisture causes a decrease in molecular weight during polymerization and storage stability, so it is recommended to thoroughly dehydrate with a dehydrating agent before use. . In addition, general-purpose solvents such as toluene, xylene, penzonitrinopebenzene, and phenol can also be used together with these solvents. However, the amount used should be within a range that does not reduce the solubility of the polyimide precursor produced.

The polyimide precursor of the present invention obtained in this manner is mainly composed of a polymer structural part consisting of a F-terminated organic tetracarboxylic acid component and a silane-modified polycarboxylic acid component as shown in the following structural formula (2). It has a structure in which a predetermined proportion of polymer structural parts are combined, or it has a polymer structure in which an unmodified organic tetracarboxylic acid component and a silane-modified polycarboxylic acid component are polymerized randomly with a diamine, All of them are characterized by having a silane bond in the molecular core of the polyimide precursor. Further, these modified polyimide precursors may further include a polyimide precursor partially composed of an unmodified organic tetracarboxylic acid or a silane-modified polycarboxylic acid alone.

The structural formula (2) below uses pyromellitic dianhydride as the organic tetracarboxylic acid component and 4.
While using 4-diaminodiphenyl ether,
An example of a polyimide precursor when the above-mentioned structural formula (1) (however, %n=2) is used as the silane-modified polycarboxylic acid component obtained by modifying the above-mentioned tetracarboxylic acid component with an aminosilane compound is shown below. This is what is shown.

According to such a polyimide precursor, by applying it to an adherend and then subjecting it to high-temperature heat treatment, it exhibits excellent adhesion or adhesion even if the adherend is various types of glass, ceramics, silicon wafers, etc. It can be converted into polyimide, and since the aromatic ring is bonded pendantly to the polymer chain in the silane-modified portion, good hydrophobicity is imparted to the polyimide polymer, which increases the initial adhesion strength. Can improve sustainability under environmental conditions. Furthermore, this polyimide also has inherently good heat resistance, chemical resistance, mechanical properties, and excellent electrical insulation properties.

Therefore, the polyimide precursor obtained by the method of this invention has the advantage that it can be applied not only to various conventionally known uses, but also as a coating material for various glasses, ceramics, silicon wafers, and the like.

Examples of this invention will be described below. In the following, the intrinsic viscosity [η] is used as a parameter indicating the degree of polymerization (molecular weight) of the polyimide precursor. It was determined according to the following formula at °C (constant temperature bath).

[η]=1n(t/lo)/C [; Falling time of a polymer solution measured with an Ubbelohde viscometer.

09 Fall time of solvent measured in the same manner as above.

C: Polyimide precursor (polymer) concentration (0.5% by weight).

Example 1 50 with a stirring device, cooling pipe, thermometer, and nitrogen purge device
0-The flask was fixed on a water bath. N-Methyl-2-pyrrolidone, which was dried over phosphorus pentoxide overnight and then distilled under reduced pressure, was 289. : l of the above flask mol), then 3
・3,4,4-biphenyltetracarboxylic dianhydride 1
．． 764F (0,006 mol) was added gradually. The temperature was controlled to below 30°C using a water bath. A silane-modified polycarboxylic acid component was synthesized by reacting until the reaction system became transparent.

Next, 20% of 4,4'-diaminodiphenyl ether was added to the above reaction system. Add OF (0.1 mol) to completely dissolve, and then add 3,3',4,4'-biphenyltetracarboxylic dianhydride 28.5185' (0,097 mol).
was added and stirred until the reaction system became a clear viscous solution. The temperature rose during this operation, but was maintained below 30°C with a water bath.

The polyimide precursor thus obtained had an intrinsic viscosity of 1.75. This precursor solution was cast onto a glass plate and dried for 1 hour at 150°C in a hot air dryer for 2 hours.
It was converted into polyimide by heating at 00"C for 1 hour and at 250"C for 6 hours. The formed polyimide film was strong and did not peel off even in tests at room temperature and PCT, and had good adhesion.

In addition, in the above Example 1, silane-modified polyol, 3.
The number of moles of 3,4,4-biphenyltetracarboxylic dianhydride is changed to 0.06 moles, and unmodified 3,4-4-biphenyltetracarboxylic dianhydride is reacted with the diamine together with the modified polyhydric carboxylic acid component in parentheses.
A polyimide precursor solution was prepared in the same manner as above except that the number of moles of '.4.4'-biphenyltetracarboxylic dianhydride was 0.07 moles. The intrinsic viscosity of the polyimide precursor in this case was 0.39. When a polyimide film was formed using this precursor solution in the same manner as above,
Both normal adhesion and PCT adhesion were good. However, because the degree of polymerization of the polyimide precursor was too low, the film-forming ability and film toughness were poor, microcracks occurred in the film, and the dielectric strength voltage was lowered to about 115 compared to Example 1.

Example 2 244.91y of purified N-methyl-2-pyrrolidone was added to the same reaction vessel as in Example 1, and Example 1 was added under a nitrogen stream.
The aminosilane compound used in 0.766'1 (0,0
03 mol) and then pyromellitic dianhydride 1
．． 308 fl (0,006 mol) were added slowly.

While controlling the temperature of the reaction system to be 30° C. or lower, the mixture was stirred until a transparent solution was obtained, thereby synthesizing a silane-modified polycarboxylic acid component.

Next, 20% of 4,4-diaminodiphenyl ether was added to this reaction system. Of (0.1 mol) was added, and pyromellitic dianhydride 21.146F (0.097 mol) was further added, and the mixture was stirred while keeping the temperature below 30°C until a transparent viscous solution was obtained.

The polyimide precursor thus obtained had an intrinsic viscosity of 1.51. This precursor solution was cast on a glass plate and heated at 150°C for 1 hour in a hot air dryer for 2 hours.
The mixture was heated at 00°C for 1 hour and then at 300°C for 1 hour to convert it into polyimide. The polyimide film formed is strong and
Adhesion was good both under normal conditions and by PCT, and no peeling from the glass plate was observed.

A polyimide precursor was produced in the same manner as in Example 2, except that 0.003 mol) was used. The intrinsic viscosity of this precursor was 1.63. Example 2 using this precursor solution
When a polyimide film was formed in the same manner as in Example 2, both the toughness and adhesion of the film were the same as in Example 2.

Comparative Example 1 Purified N-methyl-2-pyrrolidone 279.93P was added to the same reaction vessel as in Example 1, and 4.4'
20.0y- (0.1 mol) of -diaminodiphenyl ether and 29.49 (0.1 mol) of 3,3',4,4'-biphenyltetracarboxylic dianhydride were gradually added to form a transparent viscous solution. Stir until a solution is obtained. The reaction system was cooled in a water bath and controlled to be below 30°C. The intrinsic viscosity of the polyimide precursor after the reaction was 2.00.

When a polyimide film was formed on a glass plate using this solution under the same conditions as in Example 1, the film was strong and had good flexibility, but it only weakly adhered to the glass plate under normal conditions. It was easy to peel off with PCT, and it was completely peeled off with PCT.

Comparative Example 2 Instead of NH, (CH26S i (OCH3)3
A polyimide precursor was prepared using the same number of moles (0,663F, 0.003 mole). The intrinsic viscosity of this precursor was 1.58. When a polyimide film was formed using this precursor solution in the same manner as in Example 1, the adhesion and toughness of the film were both excellent as in Example 1.

However, as shown in curve 4 in the drawing, good results were not obtained regarding the adhesive strength over time under high temperature and high humidity (85° C., 85% RH).

On the other hand, according to Examples 1 to 3, as shown in curve-1 (Example 1), curve-2 (Example 2), and curve-3 (Example 3) in the drawings, Because a bulky and hydrophobic aromatic ring is pendantly bonded to the polymer chain due to the aminosilane compound, very good results were obtained in terms of adhesive strength retention properties.

Note that the drawings represent changes over time, with the initial adhesive strength of each Example and Comparative Example set at 100.

[Brief explanation of drawings]

The drawing is a characteristic diagram showing changes in adhesive strength of a polyimide film over time. Patent applicant Nitto Electric Industry Co., Ltd.0
10 20 30 40
50 Idle period (days) Procedural amendment April 5, 1982 Commissioner of the Japan Patent Office 1, Indication of the case Japanese Patent Application No. 57-2142 2, Name of the invention Process for manufacturing polyimide precursor 3, Person making the amendment Case Relationship with Patent Applicant Address 567 Postal Code q 530 6. “Detailed Description of the Invention” of the specification to be amended 7. Contents of the amendment A. Specification: (1) Page 5, line 2; “ We have corrected the text "general formula" to "general formula."

Claims (1)

[Claims] (1) In producing a polyimide precursor from the polymerization reaction ζ of an organic tetracarboxylic acid component and a diamine, a part of the above tetracarboxylic acid component is preliminarily converted to the following general formula (1).
;%Formula%(11 (However, in the formula, 1 is a monovalent organic group containing an aromatic ring, R
2 is a divalent organic group containing a carbon atom directly bonded to a silicon atom, m is an integer of 1 or 2, X is a hydrolyzable group selected from an alkoxy group, an acetoxy group, a phenoxy group, and a halogen, and Y is a Aminosilane represented by a group selected from alkyl group, alkoxy group, acetoxy group, phenoxy group, silyl group, siloxy group, disilanyl group, organosilyl group, organosiloxy group, organohalosilyl group and organohalosiloxy group) The compound is reacted with the secondary amino group (>NH) in the above general formula and at least one hydrolyzable group (X) to form the following general formula (2): %Formula% ( However, in the formula, Tcl is a monovalent residue of the organic tetracarboxylic acid component, Tc2 is a divalent residue of the organic tetracarboxylic acid component, Z is an acid group that may contain an X group bonded to a carbonyl carbon, R, , R2, m, X and Y are represented by the general formula (1
Same as in case 1, n is an integer of 2 or 3 when Y is an alkoxy group, an acetoxy group, or a phenoxy group,
(If Y is an integer consisting of 2 in cases other than the above), the silane-modified polycarboxylic acid component is characterized by polymerizing the conocarboxylic acid component with the remaining organic tetracarboxylic acid component and the diamine. Method for producing polyimide precursor.