JPH0781119B2 - Manufacturing method of polyimide molding - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a polyimide molded article, and more particularly to a method for producing a polyimide molded article that gives a laminate having excellent adhesive strength.

[Conventional technology]

Polyimide molded products, especially polyimide films, are widely used as electrical insulating materials. For example, a flexible wiring board is manufactured by adhering a polyimide film to a metal foil such as a copper foil, and an acrylic adhesive has been used as an adhesive as shown in JP-A-50-34640. It was However, the acrylic adhesive has a low heat resistance, and the original heat resistance of the polyimide film has not been fully utilized. Therefore, in order to take advantage of the heat resistance of the polyimide film,
A polyimide adhesive was developed (for example, Japanese Patent Laid-Open No. 61-6075).
(See Publication No. 5). However, the polyimide adhesive has drawbacks such that it requires complicated and long drying because it generates water when the ring is closed, and its peel strength is low due to its high elastic modulus. In order to improve the adhesive strength, it has been attempted to mechanically roughen the surface of the polyimide film by sandblasting, plasma treatment or the like (Japanese Patent Laid-Open No. 59-218789). However, mechanical roughening does not have sufficient adhesion, and plasma treatment has some effects, but requires an expensive device, and the treatment effect also decreases in a short time. On the other hand, as shown in JP-B-52-36778, there is also a method of treating a polyimide film with an alkali and then treating again with a metal salt having a smaller ionization tendency than an alkali metal. Although it is effective for use and for a specific polyimide adhesive, it has drawbacks such as insufficient effect for many other polyimide adhesives.

[Problems to be solved by the invention]

The present invention is intended to provide a method for producing a polyimide molded article which can solve the above-mentioned drawbacks of the prior art and obtain a sufficient adhesive force.

[Means for solving problems]

The method for producing a polyimide molded article of the present invention is such that after treating the surface with a solution containing a basic compound, it is treated with a silane coupling agent, and then a polyimide varnish or a polyamic acid varnish is applied to the treated surface of the heat-treated polyimide molded article. The method is characterized in that a heat-meltable adhesive layer is formed by drying, an arbitrary adherend is superposed thereon, and pressure and heat are applied at a temperature equal to or higher than the softening point of the adhesive.

The polyimide molded product used in the method of the present invention may be a film, a flexible printed wiring board, a laminated board or the like, as long as the polyimide resin is exposed on the surface. Further, the polyimide may be any one containing an imide structure such as polyamide-imide, polyether-imide, and polyester-imide.

Examples of the basic compound used in the method of the present invention include sodium hydroxide, potassium hydroxide, alkali metal hydroxides such as lithium hydroxide, and tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrabutylammonium hydroxide and the like. Quaternary ammonium hydroxide is preferable, and potassium hydroxide and sodium hydroxide are particularly preferable.

As the solvent for dissolving the basic compound, water, alcohols such as methanol, ethanol, propanol, and isopropanol, and a mixed solvent of water and alcohol are preferable.

The concentration of the basic compound in the solution containing the basic compound and the temperature for treating the polyimide molded article, the time is determined by the desired degree of treatment and is not particularly limited, but generally the concentration is 0.1 to 50% by weight, The temperature is room temperature to 80 ° C., and the time is 0.1 minutes to 1 hour. Surface treatment of a polyimide molded article with a solution containing this basic compound, for example, by dipping the polyimide molded article in the solution, an applicator,
A known method such as cast coating using a doctor knife or the like may be used. After the treatment with the solution containing the basic compound and before the treatment with the silane coupling agent, the treatment with an acid solution such as hydrochloric acid, sulfuric acid or acetic acid may be performed.

Examples of the silane coupling agent used in the method of the present invention include vinylsilane such as vinyltrimethoxysilane, epoxysilane such as γ-glycidoxypropyltrimethoxysilane, mercaptosilane such as γ-mercaptopropyltrimethoxysilane, and γ-amino. Propyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-ureido Propyltriethoxysilane, N-benzyl-γ-aminopropyltrimethoxysilane, aminoethylaminomethylphenethyltrimethoxysilane, p-aminophenyltrimethoxysilane, trimethoxysilylpropyldiethylenetriamine, 1-tri Tokishishiriru -2 Although aminosilanes such as (aminomethyl) phenyl ethane is used, inter alia mercaptosilane and aminosilanes are preferred, gamma chromatography mercaptopropyltrimethoxysilane,
γ-Aminopropyltriethoxysilane is particularly preferred.

The treatment with the silane coupling agent is performed after the treatment with the solution containing the basic compound, and the treatment method includes, for example, immersing the polyimide molded product in the silane coupling agent solution, or using an applicator or a doctor knife. A known method such as cast coating may be used.

The solvent that dissolves the silane coupling agent may be any solvent that dissolves the silane coupling agent, such as water, alcohol, acetone, ethyl acetate, or toluene.
Water, alcohol and acetone are preferred among others.

The concentration of the silane coupling agent in the silane coupling agent solution is not particularly limited, but is preferably 0.01 to 30% by weight, particularly preferably 0.1 to 5% by weight. If the concentration is less than 0.01% by weight, the effect of the treatment with the silane coupling agent is poor, and if it exceeds 30% by weight, the effect is weakened. The temperature and time of treatment are not particularly limited, but generally 0.5 at room temperature.
It is sufficient to soak for -10 minutes or leave it for 0.5-10 minutes at room temperature after coating.

After the treatment with the silane coupling agent, heat treatment is performed.
The heat treatment temperature and time must be at least above the condition that the solvent of the silane coupling agent solution can be dried.
It is preferable to carry out the treatment at a temperature of 0 ° C or higher for 1 to 60 minutes. Particularly preferably, it is carried out at a temperature of 150 to 250 ° C. for 5 to 20 minutes.

Next, a polyimide varnish or a polyamic acid varnish is applied to the treated surface of the polyimide molded article treated as described above and dried to form a heat-meltable adhesive layer.

The polyimide used in the polyimide varnish may be any one containing an imide structure, such as polyamideimide, polyesterimide, and polyetherimide, and among them, those having a softening point of 400 ° C. or lower are preferable.

The polyamic acid used in the polyamic acid varnish may be a polyimide precursor having an imide structure, such as polyamideimide, polyesterimide, or polyetherimide. Among them, a polyimide precursor having a softening point of 400 ° C. or lower is preferable.

The solvent of polyimide varnish or polyamic acid varnish is not particularly limited as long as it dissolves N-methylpyrrolidone, diglyme, polyimide or polyamic acid, for example, N, N-dimethylacetamide, N, N-dimethylformamide, N A high boiling non-broton polar solvent such as, N-diethylformamide, dimethylsulfoxide, sulfolane, methylsulfolane, tetramethylurea, hexamethylphosphoramide or butyrolactone is preferably used. These solvents may be used alone or as a mixture of two or more thereof, and further xylene, toluene, benzene, phenol, acetone, methyl ethyl ketone, diacetone alcohol, cellosolve, methyl isobutyl ketone, cresol, dioxane, cyclohexanone may be added thereto. A solvent such as the above may be added and used within a range in which the polyamic acid does not precipitate.

The concentration of the polyimide or polyamic acid in the varnish is not particularly limited, but is 5 to 40% by weight, preferably 10
From the viewpoint of forming an adhesive coating, it is preferable to set the content to -30% by weight.

As a method of applying the polyimide varnish or the polyamic acid varnish to the surface-treated polyimide molded article, dipping the molded article in the polyimide varnish or the polyamic acid varnish, or by casting using an applicator or a doctor knife. A known method may be used.

The conditions for forming the adhesive layer by drying the polyimide varnish or polyamic acid varnish applied to the surface-treated polyimide molded article are different depending on the type of solvent, whether the varnish is a polyimide varnish or a polyamic acid varnish, and the like.
Although not uniquely determined, it is generally dried at a temperature of 50 ° C to 400 ° C for 0.1 to 5 hours. That is, if the varnish is a polyimide varnish that has already been ring-closed, it may be dried at a temperature of 50 to 200 ° C. for 0.1 to 1 hour and the solvent is volatilized. On the other hand, when the varnish is a polyamic acid varnish, after drying, it is preferable to ring-close and polyimide at the time of forming the adhesive layer, in order to omit the drying step at the time of adhesion, and therefore to make it polyimide. , 100-400
It is particularly preferable to heat at a temperature of 0 ° C for 0.1 to 5 hours.

By laminating an arbitrary adherend on the adhesive layer side of the polyimide molded article having the adhesive layer thus formed, and applying pressure and heating, a laminated article having a strong adhesive force can be obtained.

The adherend may be any of a polyimide molded product, a metal foil such as a copper foil and an aluminum foil, a copper plate, an iron plate, an aluminum plate, a stainless plate, and a metal plate such as a 42 alloy plate.

Further, the conditions of pressurization and heating differ depending on the physical properties of the adhesive layer, but generally, the temperature is equal to or higher than the softening point of the adhesive, preferably equal to or higher than the softening point of the adhesive and lower than the thermal decomposition start temperature. ,
Pressure is ^{0.1kg / cm 2 ~100kg / cm 2} . This bonding method is not particularly limited, but it can be carried out, for example, by laminating an arbitrary adherend on the adhesive layer and heating and pressing in a roll laminate, a press or an autoclave.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples.
The scope of the present invention is not limited to these examples.

Example 1 Kapton 200H (manufactured by DuPont, 50 μm polyimide film) was immersed in a 30% aqueous potassium hydroxide solution at room temperature for 10 minutes and then washed with water. Next, after soaking in 1% γ-aminopropyltriethoxysilane 1% acetone solution at room temperature for 30 seconds, 20
It was dried at 0 ° C for 10 minutes.

On the other hand, 3,3 ′, 4,4′-benzophenone tetracarboxylic acid dianhydride 64.4 g, m-toluylenediamine 12.2 g, bis [4- (3-aminophenoxy) phenyl] sulfone
Dissolve 43.2g in 480g N-methylpyrrolidone and
After heating for an hour, 11.3 g of N, N'-diphenylmethane bismaleimide was dissolved to obtain a polyimide varnish. The concentration of polyimide in the varnish was 20% by weight. The obtained varnish was cast on the surface-treated Kapton using an applicator and dried at 80 ° C. for 10 minutes and then at 200 ° C. for 1.5 hours to form an adhesive layer. A 35 μm single-sided roughened copper foil was placed on this and pressed at 275 ° C. and 50 kg / cm ² for 30 minutes to obtain a copper-clad substrate. The 90 ° peel strength between Kapton and the polyimide adhesive of this copper-clad substrate was 0.83 kg / cm.

Comparative Example 1 A copper clad substrate was obtained in the same manner as in Example 1 except that γ-aminopropyltriethoxysilane was not used. The 90 ° peel strength between the Kapton and the polyimide adhesive of this copper clad substrate was 0.04 kg / cm, which was very weak.

Comparative Example 2 A copper clad substrate was obtained in the same manner as in Example 1 except that Kapton which was not treated was used. The 90 ° peel strength between the Kapton and the polyimide adhesive of this copper clad substrate was very weak at 0.05 kg / cm.

Comparative Example 3 A copper-clad substrate was obtained according to Example 1 using Kapton 200H except that the step of immersing Kapton 200H in a 30% aqueous potassium hydroxide solution at room temperature for 10 minutes was omitted. The 90 ° peel strength between the Kapton and the polyimide adhesive of this copper-clad substrate was 0.07 kg / cm.

Example 2 Kapton 200H was added to a 30% aqueous sodium hydroxide solution at room temperature for 30%.
After soaking for a minute, it was washed with water. Next, after dipping in 5% γ-mercaptopropyltrimethoxysilane 5% acetone solution for 30 seconds,
It was dried at 250 ° C for 10 minutes. An adhesive layer was formed on the surface-treated Kapton in the same manner as in Example 1, another surface-treated Kapton was overlaid and pressed at 275 ° C. and 50 kg / cm ² for 30 minutes to obtain a laminated product. . The 90 ° peel strength between the Kapton and the polyimide adhesive of this laminate was 0.92 kg / cm.

Example 3 An equimolar amount of ethylene bis trimellitate dianhydride and bis [4- (m-aminophenoxy) phenyl] sulfone were reacted in N-methylpyrrolidone at 180 ° C. for 6 hours to obtain a polyimide varnish. . The concentration of this varnish was 20% by weight. Using this varnish, a Kapton with an adhesive was prepared in the same manner as in Example 1, laminated with a 35 μm single-sided roughened copper foil, and pressed at 200 ° C. and 30 kg / cm ² for 30 minutes to prepare a copper-clad substrate. The 90 ° peel strength between the Kapton and the polyimide adhesive of this copper-clad substrate was 0.72 kg / cm.

Example 4 Equimolar amounts of 3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride and 3,3'-diaminodiphenyl ketone were stirred in diglyme for 24 hours at 15 DEG C. with appropriate addition of ethanol. A polyamic acid varnish was obtained. The concentration of this varnish was 15% by weight. This varnish was cast on a Kapton treated in the same manner as in Example 1 using an applicator,
The adhesive layer was formed by drying at 100 ° C. for 30 minutes and 220 ° C. for 60 minutes. 35μm single-sided roughened copper foil is laid on top of this, 330 ℃, 30k
It was pressed at g / cm ² for 30 minutes to obtain a copper clad substrate. The 90 ° peel strength between the Kapton and the polyimide adhesive of this copper-clad substrate was 0.65 kg / cm.

〔The invention's effect〕

As described in detail above, according to the production method of the present invention, a laminate of polyimide molded products having a strong adhesive force can be obtained, and its industrial value is great.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-57-63254 (JP, A) JP-A-48-98781 (JP, A) JP-A-54-68654 (JP, A) JP-A-54- 54058 (JP, A) JP-A-48-14401 (JP, A)

Claims (1)

[Claims] 1. A polyimide varnish or a polyamic acid varnish is applied to the treated surface of a polyimide molded product which has been treated with a solution containing a basic compound, treated with a silane coupling agent, and then heat treated, and dried to heat-melt. A method for producing a polyimide molded article, which comprises forming a possible adhesive layer, superposing an arbitrary adherend thereon, and applying pressure and heating at a temperature equal to or higher than the softening point of the adhesive.