JPH0359090B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field] The present invention relates to a method for producing an addition-type imide resin prepolymer used as a resin for impregnating a base material of a printed wiring board. [Background Art] As printed wiring boards become more densely packaged and multilayered, high adhesion between a matrix resin and a base material and low thermal expansion of the resin in printed wiring board laminates are required. This is similarly required for polyimide, which has been developed as a highly heat-resistant resin and is put into practical use as a matrix resin for printed wiring boards. When polyimide is used as a matrix resin for printed wiring boards, it is common to impregnate the base material with an addition-type imide resin prepolymer. The present inventors investigated the causes of insufficient adhesion and high coefficient of thermal expansion, and found that a major cause was the high molecular weight content of general addition-type imide resin prepolymers. Knowledge was obtained. [Object of the Invention] The present invention has been made in view of the above points, and is an additive that can provide a polyimide that does not contain a large amount of high molecular weight components, has excellent adhesion to a base material, and has a low coefficient of thermal expansion. The object of the present invention is to provide a method for producing a type imide resin prepolymer. [Disclosure of the invention] The addition type imide resin prepolymer according to the present invention has a general formula of (In the formula, D represents a divalent organic group having a carbon-carbon double bond, and R ₁ represents a divalent group containing at least two carbon atoms.) If the general formula is H ₂ N−R ₂ −NH ₂ (where R ₂ is 2 containing at least 2 carbon atoms)
Represents a valence group. ) is reacted with a diamine of By performing a low-temperature reaction between bis-imide and diamine in an aprotic polar solvent and further controlling the amount of unreacted raw materials remaining in the reacted prepolymer, we can create an addition-type imide resin that does not contain a large amount of high molecular weight components. The present invention was completed by discovering that a prepolymer can be obtained, and the present invention will be described in detail below. The unsaturated bis-imide, which is one of the starting materials of the present invention, has the general formula () It is expressed as Moreover, the general formula of diamine, which is another one of the starting materials, is represented by () H ₂ NR ₂ −NH ₂ (). Here, D in the formula () represents a divalent organic group having a carbon-carbon double bond, such as -CH=CH-,

【formula】

[Formula] and derivatives in which these hydrogen atoms are substituted with an alkyl group or a halogen group. Moreover, R ₁ represents a divalent group containing at least 2 carbon atoms. Furthermore, R ₂ in the formula () is 30 or less and at least 2
represents a divalent group containing carbon atoms. In addition, R ₁ and R ₂ in () and () may be the same or different, and may be a straight chain or branched alkylene group having fewer than 13 carbon atoms, or a a cyclic alkylene group having 1 or 6 carbon atoms,
It can also be a heterocyclic group containing at least one of O, N and S atoms, or a phenylene or polycyclic aromatic group. These various groups may have substituents that do not give rise to unnecessary side reactions under the reaction conditions. Moreover, the above R ₁ and R ₂ can also be a large number of phenylene groups or an alicyclic group. In this case, adjacent phenylene groups or alicyclic groups may be bonded directly, or may be bonded via a divalent atom such as oxygen or sulfur, or may be an alkylene group with 1 to 3 carbon atoms or less. may be coupled through one of the groups. When a plurality of these atoms or groups exist, they may be the same or different. -NR ₄ -, -P(O)R ₃ -, -N=N-,

[Formula] -CO-O-, -SO ₂ -, -SiR ₃ R ₄ -, -CONH-, -NY-CO-X-CO-NY-, -O-CO-X-CO-O-,

【formula】 【formula】 【formula】

In the above formula, R ₃ , R ₄ and Y each represent an alkyl group having 1 to 4 carbon atoms, a cyclic alkyl group having 5 or 6 carbon atoms in the ring, or phenyl or a polycyclic aromatic group. , X is a straight-chain or branched alkylene group having fewer than 13 carbon atoms, a cyclic alkylene group having 5 or 6 carbon atoms in the ring, or a monocyclic or polycyclic arylene group. represent. The group D is derived from an ethylene anhydride of the formula (), such as maleic anhydride, citraconic anhydride, tetrahydrophthalic anhydride, itaconic anhydride, and cyclodiene and one of these anhydrides. Mention may be made of the products of the Diels-Alder reaction that occur between the two. Preferred unsaturated bis-imides of formula () that can be used include the following. Maleic acid N・N'-ethylene-bis-
Imide, maleic acid N・N'-hexamethylene-
Bis-imide, N.N'-maleic acid-metaphenylene-bis-imide, N.N'-maleic acid-paraphenylene-bis-imide, N.maleic acid.
N′-4・4′-diphenylmethane-bis-imide,
[Also called N・N′-methinelene bis(N-phenylmaleimide)], maleic acid N・N′-4・4′-
Diphenyl ether-bis-imide, maleic acid N・N′-4・4′-diphenylsulfone-bis-imide, maleic acid N・N′-4・4′-dicyclohexylmethane-bis-imide, maleic acid N・
N′-α・α′-4・4′-dimethylenecyclohexane-bis-imide, maleic acid N・N′-methaxylylene-bis-imide, maleic acid N・N′-diphenylcyclohexane-bis-imide, etc. be. Preferred diamines of formula () that can be used include the following. 4,4'-diaminodicyclohexylmethane,
1,4'-diaminocyclohexane, 2,6-diaminopyridine, metaphenylenediamine, paraphenylenediamine, 4,4'-diamino-diphenylmethane, 2,2-bis-(4-aminophenyl)
Propane, penzidine, 4,4'-diaminodiphenyl oxide, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, bis-(4-aminophenyl)diphenylsilane, bis-(4- Aminophenyl) methylphosphine oxide, bis-(3-aminophenyl)methylphosphine oxide, bis-
(4-aminophenyl) phenylphosphine oxide, bis-(4-aminophenyl) phenylamine, 1,5-diaminonaphthalene, metaxylylene diamine, paraxylylene diamine, 1.
1-bis-(para-aminophenyl)phthalane, hexamethylene diamine, and the like. The above-mentioned unsaturated bis-imide and diamine are reacted in an aprotic polar solvent to prepare an addition type imide resin prepolymer. As the aprotic polar solvent, N-methyl-2-pyrrolidone, N・N-dimethylformamide, N・N-
Dimethylacetamide, 1,3-dimethyl-2-
Imidazolidinone, dimethyl sulfoxide, etc. can be used. These can be used alone or in combination of two or more. Here, the addition type imide resin prepolymer is dissolved in the solvent used for this reaction and used as a varnish to impregnate the base material. At this time, the varnish is applied to the base material using a coating machine etc. During impregnation, the varnish concentration is adjusted to 55-65% so that the resin content of the substrate is 47-50% in one impregnation step.
The concentration is set to a high level. When trying to obtain such a highly concentrated varnish, if a protic polar solvent is used instead of an aprotic polar solvent, the addition type imide resin prepolymer has good solubility in the protic polar solvent. This results in the inconvenience that solid matter may precipitate in the varnish or precipitate as cloudiness.
Therefore, in the present invention, an addition type imide resin prepolymer is prepared by reacting an unsaturated bis-imide and a diamine in an aprotic polar solvent. Further, in this reaction, the reaction temperature is set at 50°C or higher and lower than 100°C. If the reaction temperature is less than 50℃, the reaction will hardly proceed, and if the reaction temperature is 100℃ or higher, a large amount of high molecular weight substances with poor reaction activity with the base material will be formed in the addition type imide resin prepolymer. This causes the inconvenience of being exposed. Furthermore, this reaction is adjusted so that it is terminated when the remaining unreacted raw material in the addition type imide resin prepolymer reaches 35 to 50% by weight. If the residual unreacted raw material in the addition-type imide resin prepolymer is less than 35% by weight, a large amount of high molecular weight substances with poor reaction activity with the base material will be produced, and if it exceeds 50% by weight, the prepolymer will This results in the inconvenience that unreacted raw materials precipitate in the solution (varnish). Here, in order to adjust this reaction, it is necessary to measure the molecular weight distribution of the addition type imide resin prepolymer.
(HLC manufactured by Toyo Soda Co., Ltd.) equipped with two gel permeation chromatographs (8.0 x 250 mm, number of theoretical plates: 6000)
−803D). To calculate the molecular weight, a cubic regression curve is obtained from the retention times of five types of monodisperse polyethylene glycol and ethylene glycol monomers and the common logarithm of the molecular weight, this is applied to the sample, and the regression curve is calculated from the retention time of the sample. This can be done by determining the molecular weight. In addition, the proportion (%) of each component was determined using a differential refractometer ( ¹²⁸
The chromatograph obtained with a refractometer output of 0 to 1 V and a chart speed of 5 mm/min was divided into the necessary molecular weight categories, and by the cutout weight method,
It can be calculated by finding the respective ratios. Furthermore, when reacting unsaturated bis-imide and diamine, the molar ratio of unsaturated bis-imide and diamine is 1.0/1.0 to 10/1.
Generally, the ratio is preferably 1.0/1.0 to 3/1.
If the amount of unsaturated bis-imide is too large, unreacted raw materials tend to remain and precipitates are likely to occur in the prepolymer solution (varnish).On the other hand, if the amount of diamine is too large, addition-type imide This increases the amount of high molecular weight substances produced in the resin prepolymer. The prepolymer solution (varnish) of the addition-type imide resin prepolymer obtained as described above is impregnated into a base material when manufacturing a laminate for a printed wiring board, but the type of base material is not particularly limited. . Glass cloth is usually used, but other inorganic fiber cloths such as quartz fiber cloth, highly heat-resistant fiber cloths such as Kevlar fiber cloth, etc. can also be used. Then, apply prepolymer to the base material according to the conventional method.
After impregnating with the solution, prepregs are created by heating and drying, and the thus obtained prepregs are laminated together with metal foil such as copper or nickel or an inner layer material with a circuit formed thereon, and then processed according to a conventional method. A printed wiring board is obtained by lamination molding under heating and pressure. Next, the present invention will be explained with reference to examples. The raw materials shown in Table 1 were weighed into a four-necked flask (No. 3) according to the formulation shown in Table 1, and a stirring rod, a thermometer, and a condenser were attached to the flask, and then nitrogen gas was introduced into the flask from the side port. After the air in the flask was replaced with nitrogen in this manner, heating was performed using an oil bath. Stirring was started as the contents were dissolved, and the reaction was carried out by setting the heating temperature shown in Table 1. After continuing stirring for the time shown in Table 1, the reactants were quickly cooled to room temperature to obtain prepolymer solutions (Examples 1 to 4, Comparative Examples 1 to 4). Table 2 shows the analytical values and characteristic values of the addition type imide resin prepolymer solutions of Examples 1 to 4 and Comparative Examples 1 to 4 thus obtained. In Table 1, *1 indicates the structural formula *2 indicates that the structural formula is This is shown in . In Table 2, "resin composition" (wt%) is calculated from the peak area in the gel permeation chromatography (GPC) measurement. Furthermore, in Table 2, "stability" indicates the stability when each prepolymer solution is left at the set temperature (20℃, -5℃), and it indicates the stability of the solid content from the prepolymer solution. Judgment was made based on the presence or absence. In the "stability" column, ◯ indicates stability for 7 days or more, △ indicates solid analysis was detected in less than 7 days, and × indicates solid analysis was detected within 1 day.

【table】

[Table] Next, using the addition-type imide resin prepolymer solutions of Examples 1 to 4 and Comparative Examples 1 to 4, a 105 g/m ² surface-treated glass cloth was impregnated under the conditions shown in Table 3. I did it. By heating in a dryer to perform a secondary reaction, prepregs having a resin content of 47 to 50% were produced (Examples 5 to 8, Comparative Examples 5 to 8). Table 3 shows the properties of the obtained prepreg. Next, the prepreg obtained in this way was
x 30 cm in size, stack 4 of these, perform surface treatment on both outermost surfaces, place 0.5 oz/ft ² copper foil of the same size, and sandwich this between 1.6 mm thick molds. While applying a pressure of 5 kg/cm ² using a steam press, the mixture was immediately heated to 130° C. and held for 20 minutes. Furthermore, set the pressure to 10Kg/cm ² and 170
℃, and after 90 minutes, cooled to room temperature while applying pressure to obtain double-sided copper-clad laminates (Examples 9 to 12, Comparative Examples 9 to 12). Table 4 shows the performance of the obtained laminate. In Table 3, "resin composition" is calculated from the peak area in GPC measurement, and the criteria for "prepreg appearance" are: ○: no resin unevenness, ×: resin unevenness. Furthermore, the criteria for the "plate appearance after etching" in Table 4 are: ○: no scratches or voids, ×: scratches or voids, and the "coefficient of thermal expansion" is 40 to 250℃.
This is the average value of the dimensional changes measured up to.

【table】

[Table] As shown in Tables 1 and 2, an aprotic polar solvent is used as the solvent, the reaction temperature is set at 50 to 100°C, and the reaction is carried out so that the remaining unreacted raw material is 35 to 50%. The prepared addition-type imide resin prepolymers of Examples 1 to 4 had excellent stability as shown in Table 2, excellent prepreg appearance as shown in Table 3, and excellent prepreg appearance as shown in Table 4. It is confirmed that printed wiring boards have high interlayer adhesion and low coefficient of thermal expansion. Therefore, it is confirmed that the addition type imide resin prepolymer produced in the present invention provides a polyimide exhibiting high adhesiveness and low coefficient of thermal expansion. [Effect of the invention] As mentioned above, the present invention has the general formula (In the formula, D represents a divalent organic group having a carbon-carbon double bond, and R ₁ represents a divalent group containing at least 2 carbon atoms) as an unsaturated bis-imide, If the general formula is H ₂ N−R ₂ −NH ₂ (where R ₂ is 2 containing at least 2 carbon atoms)
Represents a valence group. ) is reacted with a diamine in an aprotic polar solvent at a temperature of 50°C or more and less than 100°C until the remaining unreacted raw material becomes 35 to 50%. By using a polar solvent, setting the reaction temperature at 50-100℃, and adjusting the reaction so that the remaining unreacted raw material is 35-50%, it exhibits high adhesion to the substrate and low coefficient of thermal expansion. It is possible to obtain an addition type imide resin prepolymer.

Claims (1)

[Claims] 1. The general formula is (In the formula, D represents a divalent organic group having a carbon-carbon double bond, and R ₁ represents a divalent group containing at least 2 carbon atoms) as an unsaturated bis-imide, If the general formula is H ₂ N−R ₂ −NH ₂ (where R ₂ is 2 containing at least 2 carbon atoms)
Represents a valence group. ) with a diamine in an aprotic polar solvent at a temperature of 50°C or more and less than 100°C until the remaining unreacted raw material becomes 35 to 50%. Manufacturing method.