JP3064386B2 - Laminated sheet - Google Patents

Description

The present invention relates to a heat-resistant laminated sheet,
More specifically, the present invention relates to a laminated sheet using a heat-resistant film in which a resin having low heat resistance and an aromatic polyamide are blended.

[Prior art] Conventionally, in order to obtain a heat-resistant laminated sheet, a method of laminating an aromatic polyamide or polyimide film using an adhesive or forming an intermediate layer as in Japanese Patent Publication No. 1-36785 is known. It has been disclosed.

[Problems to be Solved by the Invention] However, as a laminating method, since a film of an aromatic polyamide or polyimide having high heat resistance usually does not have a melting point, a solvent which dissolves the film through an adhesive layer such as an adhesive or the like is used. In addition, when forming an intermediate layer, a complicated method must be used, which increases costs.Also, the adhesive layer may adversely affect the characteristics. There are drawbacks such as the use of aggravating solvents.

An object of the present invention is to improve such a problem and to provide a laminated sheet excellent in heat resistance, mechanical properties, and economy (cost).

[Means for Solving the Problems] The present invention relates to an aromatic polyamide containing at least 50 mol% of one or more repeating units represented by the following general formula, and 1% by weight or more in a solvent in which the aromatic polyamide is dissolved. A laminated sheet formed by laminating two or more films made of a blended resin with a soluble resin that dissolves without interposing an adhesive layer, wherein the amount of the aromatic polyamide constituting the film is 5% by weight or more of the blended resin. A laminated sheet having a content of 90% by weight or less.

(Ar ₁ and Ar _{2 each} have at least one kind of structure containing at least one aromatic ring.) The aromatic polyamide of the present invention is one kind or more of the general formula It contains at least 50 mol% of the repeating unit represented by the formula, more preferably at least 70 mol%.

Here, Ar ₁ and Ar ₂ are composed of one or more structures containing at least one aromatic ring, and may have the same composition or different ones. Representative examples thereof include the following.

Also, part of the hydrogen on these aromatic rings are halogen (especially chlorine), a nitro group, an alkyl group of C ₁ -C ₃ (especially methyl), such as alkoxy groups C ₁ -C ₃ Also includes those substituted with a substituent. X represents —O—, —CH _{2
-, - SO 2 -, -} S -, - CO- , and the like. These are included in the form of homopolymer or copolymer.

From the viewpoint of improving the heat resistance which is the object of the present invention, Ar ₁ ,
Ar ₂ preferably has a rigid structure mainly in a para-orientation, and those having a substituent such as a halogen group or an alkyl group on the aromatic ring are more preferable because of high solubility in a solvent and compatibility with a soluble resin. Further, a halogen group is preferable because it improves the humidity characteristics of the obtained film.

Further, solubility in solvents, from the viewpoint of compatibility with the soluble resin is _{high, -O -, - CH 2 -} , - SO 2 -, - S -, - CO- is two aromatic rings via a It is also preferable that the bonded structure is copolymerized, but if it is too large, the thermal characteristics, mechanical characteristics, and humidity characteristics are adversely affected.

_{That, Ar 1: (Ar 3)} a (Ar 4) b (Ar 5) c Ar 2: (Ar 6) d (Ar 7) e , however, a + b + d + e > 0.5 b + e> 0.5 c <0.4 Ar ₄ , Ar ₇ : Ar ₃ , Ar ₆ nucleus-substituted (eg halogen) Is preferable. Ar ₁ , Ar ₂
The groups other than Ar ₃ , Ar ₄ , Ar ₅ , Ar ₆ , and Ar ₇ constituting the above are not particularly limited as long as the above formula is satisfied.

For example, A solution of one or more aromatic polyamides represented by, for example, a soluble resin, the pot life is extremely stable even when stored for a long time, and the resulting film is tough and has good heat resistance and good humidity characteristics. .

In addition, the soluble resin of the present invention means one or more resins that dissolve at 1% by weight or more in a solvent that dissolves the aromatic polyamide described above, and is not particularly limited. As a solvent for dissolving both the aromatic polyamide and the soluble resin, an organic solvent is preferable in consideration of ease of handling and the like, and N-methyl-2-pyrrolidone, dimethylacetamide, hexamethylenephosphoramide, dimethylformamide, dimethylformamide Examples include amide polar solvents such as imidazolidinone and dimethyl sulfone.
Mixtures of -methyl-2-pyrrolidone and N-methyl-2-pitridone with other amide polar solvents are preferred. Particularly when these solvents are used, polycarbonate, polyvinylidene fluoride, polymethyl methacrylate, polystyrene, polyvinyl alcohol, polyether sulfone, polysulfone, polyarylate, polysulfide sulfone polyetherimide, and the like are preferable, and mechanical properties at high temperatures are improved. Amorphous resins which are remarkable and have excellent humidity characteristics, such as polycarbonate, polyether sulfone, polysulfone, polyarylate, and polysulfide sulfone, are more preferable. In particular, And the basic skeleton A of Since the resin having both the structures of (1) and (2) has very good compatibility with the aromatic polyamide, a blend solution obtained by dissolving the aromatic polyamide and the soluble resin in the above solvent has excellent long-term storage stability, It is more preferable because a film having excellent properties and transparency can be obtained. For example, polycarbonate, polyarylate and the like can be mentioned, and polycarbonate is more preferred from the viewpoint of economy. The basic skeleton A may have a substituent, such as a halogen group. Further, in addition to the blend resin of the aromatic polyamide and the soluble resin, another resin as the third component is preferably 40% by weight or less, more preferably 30% by weight or less, further preferably 20% by weight or less of the soluble resin. For example, when polycarbonate is used as the soluble resin, the addition of polyethersulfone, polysulfone, or the like improves mechanical properties. Further, in addition to the above solvents, good solvents for soluble resins, for example, dioxane, tetrahydrofuran, methylene chloride, chloroform, 1,1,2-trichloroethane, tricrene,
Acetone, toluene, etc. may be contained within a range that does not prevent the soluble resin and the aromatic polyamide from being compatible with each other, preferably within 20% by weight of the total solvent amount, more preferably within 15% by weight. I don't support it.

A film made of the blended resin is first obtained by forming the above-mentioned blend solution into a solution.

It is necessary that the amount of the aromatic polyamide in the film of the present invention is in the range of 5% by weight to 90% by weight of the blend resin. When the amount of the aromatic polyamide is less than this range, the effect of improving the heat resistance is no longer observed, and the mechanical properties at high temperatures are extremely deteriorated. It is preferably at least 7% by weight, more preferably at least 10% by weight. On the other hand, if the amount of the aromatic polyamide is larger than this range, there is no economic merit, and not only the humidity characteristics are deteriorated, but also the adhesive strength between the films is reduced when the films are laminated, and the films may be separated. . Preferably not more than 70% by weight, more preferably 50%
% By weight or less.

Further, Ra (center line average roughness) of the surface of the film of the present invention
Is preferably 10 to 500 nm, more preferably 30 to 300 nm. If the thickness is smaller than this range, the handleability of the film will be deteriorated, the film will be damaged, insulation defects will increase, and the mechanical properties will also deteriorate. If it is too large, the surface of the film will be too uneven, resulting in poor adhesion.

In order to achieve the above surface roughness, inorganic and organic fine particles are added, and the added amount is preferably 0.05 to 10% by weight.
0.1 to 5% by weight is more preferable) and particle size (average particle size is 0.0
It is effective to adjust the stretching temperature and the stretching ratio, preferably from 05 to 1.0 μm, more preferably from 0.01 to 0.8 μm.

Under a load of at least one direction (0.5 k
The thermal dimensional change at 250 ° C. in g / mm ² ) is preferably 50% or less.
If it is larger than 50%, it cannot be used in applications in which tension is applied at a high temperature after forming a laminated sheet. It is more preferably at most 40%, further preferably at most 20%.

The heat shrinkage at 250 ° C. in at least one direction of the film obtained in the present invention is preferably 20% or less. It is more preferably at most 10%, further preferably at most 5%. 20%
If it is larger, the dimensional stability is poor and it cannot be put to practical use.
The heat shrinkage at 200 ° C. in at least one direction is preferably 10% or less, more preferably 5% or less. Further, the heat shrinkage at 300 ° C. in at least one direction is preferably 30% or less, more preferably 20% or less. Further, the coefficient of thermal expansion in at least one direction is preferably 5 × 10 ⁻⁵ / ° C. or less,
^-5 / ° C or less is more preferable. If it exceeds 5 × 10 ^-5 / ° C, it cannot be used for flexible circuit boards.

The moisture absorption of the film is preferably 5% or less, more preferably 3% or less, and still more preferably 1% or less. 5%
If it is larger, the dimensional change due to moisture absorption becomes large, and it is not practical. The coefficient of humidity expansion in at least one direction is 5
× 10 ⁻⁵ /% RH or less is preferable. It is more preferably 4 × 10 ⁻⁵ /% RH or less.

The film of the present invention has an elongation at break in at least one direction of 10
% Or more is preferable. It is more preferably at least 15%, further preferably at least 20%. If it is less than 10%, the film will be broken during handling and processing of the film, which is not practical. The strength in at least one direction is preferably 5 kg / mm ² or more, more preferably 7 kg / mm ² or more, and further preferably 9 kg / mm ² or more. The Young's modulus in at least one direction is preferably 150 kg / mm ² or more, more preferably 200 kg / m
m ² or more.

The thickness of the film of the present invention is preferably 0.2 to 200 μm,
1 to 50 μm is more preferred. The density of this film is
1.0 to 1.5 g / cm ³ is preferable, and 1.1 to 1.4 g / cm ³ is more preferable.

Further, the tear resistance in at least one direction of the film of the present invention is preferably 0.05 kg / μm or more. If it is less than this, the film will be broken during handling and processing of the film, which is not practical. More preferably, it is 0.1 kg / μm or more, further preferably 0.3 kg / μm or more.

Next, the film production method of the present invention will be described, but is not limited thereto.

The aromatic polyamide of the present invention is obtained by the reaction of diitonate and dicarboxylic acid, or diacid chloride and diamine. In the case of diacid chloride and diamine, N-
It is synthesized by solution polymerization in an amide-based polar solvent such as methyl-2-pyrrolidone or dimethylacetamide, or by interfacial polymerization using an aqueous medium. Diacid chloride and diamine are mixed at low temperature (usually 50 ° C)
(Preferably 30 ° C. or lower)) for 1 to 2 hours with stirring. The order of adding the monomers is not particularly limited. Hydrochloric acid generated after the polymerization is neutralized with an inorganic alkali or an organic neutralizing agent. The reaction between the diisocyanate and the dicarboxylic acid is carried out in an amide-based polar solvent in the presence of a catalyst, usually at a high temperature (50 to 200 ° C.). These polymer solutions may be directly used as stock solutions for blending,
Alternatively, the polymer may be isolated once and then redissolved in a solvent to prepare a stock solution for blending. In some cases, an inorganic salt such as calcium chloride or magnesium chloride is added to the stock solution for blending as a solubilizing agent.

In order to improve the mechanical properties of the film of the present invention, it is necessary to keep the molecular weight of the polymer at a certain level or more, and it is convenient to _{express the} intrinsic viscosity (η _inh ) as a measure for this. That is, when the intrinsic viscosity dissolves in N-methyl-2-pyrrolidone, it is preferably 1.0 to 10.0, more preferably 1.5 to 7.0.

As a method of blending the aromatic polyamide and the soluble resin, a method of separately preparing a stock solution of each aromatic polyamide-soluble resin and blending the stock solutions with each other, and adjusting an amide-based polar solvent solution in which the soluble resin is dissolved. Among them, there is a method in which the above-mentioned polymerization of the aromatic polyamide is carried out, and the polymerization and the blending are carried out simultaneously. In particular, when separately preparing the respective blend stock solutions of the aromatic polyamide and the soluble resin and blending the stock solutions, the temperature of the solution is 25 to 100 ° C., preferably 30 to 80 ° C.
It is preferable to stir at 30 ° C for 30 minutes or more. If the temperature is lower than this and the stirring time is not sufficient, the surface may become rough when formed into a film. Then, as described above, inorganic and organic fine particles are added in order to control the surface roughness of the film. The apparent intrinsic viscosity obtained from the membrane-forming stock solution thus obtained is preferably from 0.1 to 8.0, more preferably from 0.2 to 5.0. The solution viscosity can be freely selected, but from the viewpoint of castability is preferably 5 to 50,000 poise / 30 ° C., and 10 to
20000 poise is more desirable. The resin concentration is preferably 1 to 50%, more preferably 5 to 30%.

This film forming stock solution is formed into a film by the following method. First,
Although it is a dry-wet method, it is cast on a support in the form of a film by a doctor knife, a mouthpiece, or the like, and is usually dried at a temperature in the range of 50 to 250 ° C, more preferably 60 to 200 ° C for a certain time. If the temperature is lower than 50 ° C., the evaporation rate of the solvent is slow. The dried film is peeled from the support, and immersed in or sprayed with an aqueous medium to extract the inorganic salt and the solvent. The aqueous medium is a liquid containing water as a main component and is a poor solvent for polymers, but a liquid having an affinity for inorganic salts and amide polar solvents. For example, water alone, a mixture of water and an amide-based polar solvent constituting a stock solution, a mixture of water and ethylene glycol, acetone, and a lower alcohol may be mentioned. At least 50% or more of the water is desalinated. It is desirable in consideration of the rate of solvent removal and solvent recovery. The temperature of the wet bath is usually 5 to 90 ° C. In the wet process, an inorganic salt serving as a dissolution aid and an amide-based polar solvent are extracted. In the film immediately after the completion of the wet process, the residual amount of the inorganic salt is 3% or less per polymer, more preferably 1%. The following is good. The residual ratio of the amide polar solvent is not particularly limited, but it is advantageous to extract as much as possible in consideration of solvent recovery. The film in the wet process is easily stretched in a wet temperature range because it is swollen with an aqueous medium, and in order to improve the mechanical properties of the final film, it is generally stretched in the longitudinal direction by 1.01 to 5.0 times in the process. You. The film after the wet process is heated for evaporation of the aqueous medium and evaporation of the amide polar solvent. In this heating step, the final treatment is 100 ° C. or higher, preferably 200 ° C. or higher and 500 ° C. or lower. However, once the water is dried at 50 to 100 ° C. Up to this point), heating at the above-mentioned temperature is preferred because a film having the heat and mechanical properties of the present invention can be easily obtained. Also,
In the heating step, the film is stretched 1.0 to 5.0 times in the transverse direction.
If the film is stretched once at 1.0 to 1.2 times at 00 to 200 ° C. and then stretched at 200 to 500 ° C. in two steps, a film having the surface characteristics of the present invention can be easily obtained. . Also, there is no problem if relaxing is performed as needed.

Next, the wet method is a method in which a film is formed directly on a support or once on a support on a film, and introduced into an aqueous medium (which may contain alcohol such as methanol or ethanol or may contain only alcohol). is there. Because it contains a large amount of amide-based polar solvents, etc., the rapid replacement of inorganic salts and amide-based polar solvents in aqueous media is likely to cause the generation of voids or roughening of the film in the final film. Inorganic salts such as calcium chloride, lithium chloride, lithium bromide, etc. are included in the aqueous medium to control the substitution rate as necessary, or water is provided in multiple stages, and water and amide-based polar solvents / inorganic salts are used. Or a mixture having a concentration gradient. Like the dry-wet method, the film may be stretched 1.01 to 5 times in the machine direction in this step. The film after the wet process is heated (200 to 500 ° C.) and stretched in two stages in the horizontal direction (1.01 to 5.0 times) in the same manner as in the dry and wet process. Prior to this heating, it is preferable to dry the water once at 50 to 100 ° C., and the drying is performed by a hot roll or hot air.
A longitudinal stretching of up to 5 times is also performed.

Next, a dry method is used. This method is a process in which the extraction step is omitted, contrary to the wet method, and is a method that can be performed only by using an organic solvent and not containing an inorganic salt as a dissolution aid in a stock solution for film formation. The undiluted solution cast onto the support from a doctor knife or mouthpiece is dried and peeled off from the support in the same manner as in the wet-wet method, and the solution is moved 1.01 vertically between the support and the heating step.
Stretched up to 5.0 times. After the dry process, the film is heated and stretched in the same manner as in the dry-wet process. As described above, the film of the present invention can be obtained.

 Next, a method of laminating a film will be described.

The film obtained as described above can be laminated by wet lamination using a solvent in which a commonly used film is dissolved or dry lamination using an adhesive, but in the case of the film of the present invention, the film is simply a film. Is characterized in that the laminated sheet of the present invention can be produced only by laminating and thermocompression bonding. For example, it is performed by a roll press, a hot plate press or the like under the conditions of a temperature of 150 to 350 ° C. and a pressure of 1 to 20 kg / cm ² . When three or more layers are stacked, the layers may be stacked one by one or simultaneously.

The films to be laminated may have the same composition or different films.

When laminating long films, the laminating direction may be the same, orthogonal, or intermediate therebetween, and can be selected depending on the application.

The thickness of the laminated sheet obtained as described above varies depending on the thickness of the film to be used and the number of layers, but is 5 μm to
5 mm is preferable, and 10 μm to 1 mm is more preferable.

[Evaluation Method of Characteristics] The measurement methods of the characteristics in the examples are as follows.

(1) Intrinsic viscosity (ηinh) The intrinsic viscosity was measured using an Ubbelohde viscometer under the conditions of 0.5 g / 100 ml and 30 ° C. using N-methyl-2-pyrrolidone as a solvent according to the following equation.

(2) Solution Viscosity (Poise) Measured at a temperature of 30 ° C. using a rotary B-type viscometer (Tokyo Keiki).

(3) Elongation at break, strength, Young's degree, F-5 value 10mm width, 50mm length, tensile speed 3 using TRS type tensile tester
It was measured under the condition of 00 mm / min.

(4) Heat shrinkage (%) After heating for 10 minutes in an oven set at a predetermined temperature with no load, the temperature was returned to room temperature, the dimensions were measured, and calculated by the following formula.

(5) Moisture Absorption (%) The film weight was measured after absolute drying at 150 ° C. for 60 minutes and after being left in 75% RH for 48 hours, and calculated by the following formula.

Moisture absorption = (film weight after standing at 75% RH for 48 hours-film weight when absolutely dry) / (film weight when absolutely dry) x 10
0 (%) (6) Coefficient of thermal expansion (α) To eliminate the effects of heat shrinkage and moisture absorption and
It calculated from the dimensional change in the 80-150 degreeC area | region at the time of heating to ℃ and gradually cooling. The dimensional change was measured by a thermomechanical analyzer (TMA).

(7) Humidity expansion coefficient (β) Dehumidification (approx. 30% RH) and humidification (approx.
% RH), the film length at the time of equilibrium was read, and the difference (elongation) was obtained from the following equation.

(8) Rate of thermal dimensional change under load A 0.5 kg / mm ² load was applied to the oven at a temperature of 250 ° C. for 10 minutes, the temperature was returned to room temperature, and the dimensions were measured.

(9) Center line average roughness Ra was measured using a high-precision thin film step measuring device ET-10 manufactured by Kosaka Laboratory. The conditions are as follows, and the value was determined by averaging 20 times.

・ Stylus tip radius: 0.5 μm ・ Stylus load: 5 mg ・ Measurement length: 1 mm ・ Cutoff value: 0.08 mm The definition of the center line average roughness Ra is, for example, the following: Evaluation Method ”(General Technology Center, 19
83).

(10) Edge crack resistance (kg / μm) Measured in accordance with JIS-C-2318 and converted to a thickness of 1 μm.

(11) Solder resistance A 20 mm square sample was placed in a 260 ° C ± 2 ° C solder bath.
After floating for 0 second, the sample was taken out and no deformation was observed.

(12) Adhesion The sample after the solder resistance test, in which no peeling of the films was observed, was judged to be good.

[Examples] Next, embodiments of the present invention will be described based on examples, but the present invention is not limited to these. The parts used in the following examples all represent parts by weight, and the characteristic values different in the vertical and horizontal directions are average values.

Example 1 (1) Production of film 70 mol% of 2-chloroparaphenylenediamine (hereinafter C)
PA) and 30 mol% of 4,4'-diaminodiphenyl ether (hereinafter abbreviated as 4,4'-DAE), and 100 mol% of 2-chloroterephthalic acid chloride (hereinafter abbreviated as CTPC) and N-methyl-2- The reaction was performed at 20 ° C. or lower in pyrrolidone (hereinafter abbreviated as NMP) to obtain an NMP solution of an aromatic polyamide. This solution was poured into a large amount of water, reprecipitated and dried to obtain a powdery polymer. 20 parts of this polymer was dissolved in 200 parts of NMP, and NMP containing 30 parts of polycarbonate which had been separately adjusted
200 parts of the solution was added, the mixture was stirred at 40 ° C. for 4 hours, and 0.2% by weight (based on the total polymer amount) of Syloid 150 (Fuji Divison Chemical) was added to obtain a blend solution.
The intrinsic viscosity was 1.1 and the solution viscosity was 530 poise.

This stock solution for film formation was cast on an endless belt made of stainless steel, and dried with hot air at 160 ° C. until it had self-supporting property. The gel film having self-supporting properties was continuously peeled off from the belt, and then introduced into a water tank, and simultaneously with extraction of the solvent, stretched 1.1 times in the machine direction and guided to a stenter. Dry the water at 80 ° C under constant length with a stenter,
After stretching in the transverse direction by 1.3 times at 160 ° C., the film was further stretched in the transverse direction by 1.5 times (2 times in total) at 280 ° C. to obtain a film having a thickness of 10 μm. Elongation at break of the obtained film: 28%, tensile strength: 11 kg / mm ² , Young's modulus: 420 kg / mm ² , end crack resistance: 0.58
kg / μm, heat shrinkage at 250 ° C for 10 minutes: 0.5%, 250
Thermal dimensional change under a load of 0.5 ° C (0.5 kg / mm ² ): 17%, coefficient of thermal expansion (α): 2.3 × 10 ^-5 / ° C, moisture absorption: 0.8%, Ra: 120 nm,
The film was tough and excellent in humidity characteristics, heat resistance and workability.

(2) Production of Laminated Sheet The films obtained as described above were cut into 15 cm squares, 15 sheets were stacked, and hot-pressed at 280 ° C. and 10 kg / cm ² for 5 minutes. The solder resistance of the obtained laminated sheet was good, and the adhesion between the films was also excellent.

Example 2 Aromatic polyamide isolated after reaction of 70 mol% of CPA, 30 mol% of 4,4'-diaminodiphenyl sulfone (hereinafter abbreviated as DAS), 50 mol% of CTPC, and 50 mol% of terephthalic chloride (hereinafter abbreviated as TPC) A solution prepared by dissolving 35 parts in 300 parts of NMP and an NMP solution 100 containing 15 parts of polycarbonate
Part, 0.3% colloidal silker with 0.3μm particle size
(Vs. polymer). From this blend solution,
A film was produced in the same manner as in Example 1. The obtained film had a thickness of 32 μm, a tensile elongation of 22%, a tensile strength of 14 kg / mm ² , a Young's modulus of 430 kg / mm ² , and a crack resistance of 0.44 kg /.
μm, thermal shrinkage at 250 ° C. for 10 minutes: 0.5%, thermal dimensional change under load at 250 ° C. (0.5 kg / mm ² ): 11%, moisture absorption: 1.2
%, Ra: 105 nm, which was tough and excellent in humidity characteristics, heat resistance and workability. Further, using this film, a two-layer laminated sheet was produced using a press roll at 280 ° C. and 10 kg / cm ² , and both the solder resistance and the adhesiveness were good.

Example 3 In the same manner as in Example 1, CPA 85 mol%, 4,4'-DAE15
An NMP solution containing 10 parts of an aromatic polyamide obtained from a reaction of 100 mol% of CTPC and 100 mol% of CTPC, 40 parts of polyether sulfone, and 0.2% by weight of thyroid 150 (based on the polymer) was prepared. The solution viscosity was 80 poise at 30 ° C. This blend stock solution is continuously extruded into water from a die with a width of 100 mm and a slit of 0.1 mm, stretched 1.05 times in water in the longitudinal direction,
After drying the water at 95 ° C., the film was heated while stretching at 150 ° C. in the transverse direction by 1.2 times and further at 310 ° C. by 1.3 times in the transverse direction to obtain a long film. The resulting film has a thickness of 4 μm,
Tensile elongation: 20%, tensile strength: 12 kg / mm ^2, Young's modulus 450k
g / mm ² , end crack resistance: 0.06 kg / μm, thermal shrinkage at 250 ° C. for 10 minutes: 0.3%, thermal dimensional change under a load of 250 ° C. (0.5 kg / mm ² ): 7.1%, The film was tough and excellent in humidity characteristics, heat resistance and workability, with a moisture absorption rate of 0.7% and a Ra of 95 nm. Further, when a laminated sheet was prepared using this film in the same manner as in Example 1, both the solder resistance and the adhesiveness were good.

Comparative Example 1 A syloid was added to a chloroform solution of polycarbonate.
Example 1 with the addition of 0.2% by weight (based on the amount of polymer) of 150
When a 40 μm film was prepared and two layers were laminated in the same manner as in the above, workability was not a problem, but heat resistance was poor and solder resistance was extremely poor.

Comparative Example 2 An 8 μm film produced by adding 0.18% by weight of Aerosil R972 (Nippon Aerosil) to an NMP solution of aromatic polyamide obtained from 75 mol% of CPA, 25 mol% of DAE and 100 mol% of CTPC was prepared in the same manner as in Example 1. However, the films did not adhere to each other, and a laminated sheet could not be obtained.

[Effect of the Invention] The laminated sheet obtained by the present invention has excellent heat resistance, is easy to produce, and is inexpensive. Further, there are features such as improvement of mechanical properties as compared with the case of a single film, and obtaining a thick film which cannot be obtained with a single film.

Further, since no adhesive layer is interposed, deterioration of the adhesive layer does not lower the characteristics of the laminated sheet.

The laminated sheet of the present invention is most suitable for insulating materials such as motors and transformers that require heat resistance and the like. For example, a hermetic motor that is used while immersed in refrigerator oil,
Various motors such as servo motors and vehicle motors,
It can be used as an insulating material for various transformers such as gas transformers, oil transformers, and mold transformers, and generators.

Further, since it has excellent radiation resistance and low-temperature characteristics, it is most suitable as an electrical insulating material or a covering material for a superconducting material of a device requiring radiation resistance such as a nuclear power plant.

It is also suitable for covering materials of electric wires, printed boards, belts and interior materials, diaphragms, acoustic diaphragms, and the like.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B32B 1/00-35/00

Claims (1)

(57) [Claims] 1. A blend resin of an aromatic polyamide containing at least 50 mol% of one or more repeating units represented by the following general formula, and a soluble resin soluble at 1% by weight or more in a solvent dissolving the aromatic polyamide. A laminated sheet obtained by laminating two or more layers of a film comprising no adhesive layer, wherein the amount of the aromatic polyamide constituting the film is in the range of 5% by weight to 90% by weight of the blend resin. A laminated sheet characterized by the above-mentioned. (Ar ₁ and Ar _{2 each} have at least one structure containing at least one aromatic ring.)