JP2008291099A - Polyimide film and molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyimide film the moldability, processability and flame retardancy of which are improved and which is suitable as a base material of a reflector for lighting fixtures and a base material of a three-dimensional wiring board and to provide a molding using the polyimide film. <P>SOLUTION: The polyimide film has ≥33% limiting oxygen index (LOI) and 250-300°C glass transition temperature (Tg). The polyimide film is used in the molding 1. The molding is preferably used as the reflector for lighting fixtures which has a main body part 2 for forming a reflective surface, an outer flange part 4 and an inner flange part 6. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polyimide film excellent in flame retardancy and a molded body using the same, and more specifically, the moldability, workability, and flame retardancy are improved, and a reflector base for lighting equipment and a three-dimensional wiring board base The present invention relates to a polyimide film suitable as a material and a molded body using the same, particularly a reflector substrate for lighting equipment and a three-dimensional wiring board.

  It is known that bulbs such as halogen bulbs and xenon bulbs are used as light sources for automobile headlamps and fog lamps, and the temperature near the base is over 200 ° C. As the reflecting base material of the reflector (lamp reflector), plastic whose heat resistance is improved by mixing glass, metal, or an inorganic reinforcing material such as glass fiber or calcium carbonate is used.

  However, when glass is used as a reflective substrate, there are problems such as high weight and easy breakage. On the other hand, when a metal and a reinforced resin molded body are used for the reflective base material, secondary processing such as a resin coat is required before the reflective material is deposited in order to improve the reflective mirror surface performance (smoothness). There were problems such as many manufacturing steps. For those using a reinforced resin molded body as a base material, the overall thickness of the base material itself is low because of the strength of the base material and restrictions on molding technology. In a lamp having a structure that is easy to do, there is a fear of heat resistance in maintaining the shape, and there is a problem that the temperature in the housing is increased and the life of the bulb is shortened. In addition, a gas such as a chlorine compound is generated when the lamp is lit and heated, and adheres to and solidifies on an entire surface lens such as a headlamp to cause the lens to become cloudy, thereby deteriorating lamp performance.

  On the other hand, a sheet-made reflector made of a film sheet that has been mirror-finished by depositing aluminum (for example, see Patent Document 1) is known, and this sheet-made reflector does not require pretreatment such as degreasing to obtain mirror surface However, since the film sheet used here is made of polyethylene which is inferior in heat resistance, the reflector made of this sheet is a reflector such as a headlamp using a high heat-generating lamp such as a halogen bulb. It was impossible to apply as the heat resistant shape retaining force.

  Further, a reflecting mirror (see, for example, Patent Document 2) in which a visible light reflecting infrared transmission multilayer film is formed on a reflector substrate made of a polyimide resin and a polyether ketone resin film is known, and this reflecting mirror is damaged. Although it is disclosed that it can withstand the heat generation of halogen spheres by using polyimide resin etc. in addition to the difficulty, etc., this reflecting mirror has a visible light reflecting infrared transmission multilayer film on the substrate. And cannot be used as a reflector for automobile headlamps and fog lamps.

  Furthermore, a reflector substrate for lighting equipment made of a molded body of an aromatic polyimide film or an aromatic polyamide film (for example, see Patent Document 3) is known. This reflector base material can withstand the heat generated by halogen spheres by using polyimide film in addition to its resistance to breakage, but non-thermoplastic film as a reflector base material for lighting equipment. Alternatively, when a thermoplastic film having a high glass transition point is used, the heating temperature required for the film during the molding process is high and it is difficult to control the temperature conditions. In molding by the pressure method, it takes a long time to mold heating and cooling, so the molding time becomes long, and it is not suitable for practical use in terms of cost and mass production. Conversely, a thermoplastic film with a low glass transition point was used. In that case, there was a problem that the heat resistance of the obtained reflector base for lighting equipment was poor.

  In view of this situation, as a result of continuous studies, the present inventors have previously proposed a reflector substrate for lighting equipment (see, for example, Patent Document 4) made of a molded body of a specific thermoplastic aromatic polyimide film. This reflector base material for lighting equipment is lightweight and has excellent surface smoothness, safety, moldability, heat resistance and handleability, and is suitable for mass production without the need for pretreatment when forming a reflective layer. In addition to being excellent in heat resistance, heat dissipation, safety and handleability, it has the characteristics of low cost and high quality. However, since this reflector base material for lighting equipment has failed in the flame retardancy test of UL94, it is required to realize a reflector base material for lighting equipment that has further imparted flame retardancy in addition to the above characteristics. It was done.

In addition to the reflector base for lighting equipment, the molded body has been used for electronic board applications and has been sought to develop a three-dimensional wiring board. However, in the flame retardancy test of UL94, the flame retardancy is insufficient. Yes, it was not possible to develop in these fields due to insufficient flame retardancy.
Japanese Utility Model Publication No. 62-1087 Japanese Patent Publication No. 5-88481 JP-A-10-96765 JP 2001-083310 A

  The present invention has been achieved as a result of studying the solution of the problems in the prior art described above as an issue.

  The first object of the present invention is light weight, excellent in surface smoothness, safety, moldability, heat resistance, flame retardancy, and handleability, and is a reflector base for lighting equipment such as a lamp reflector and a base for a three-dimensional wiring board. The object is to provide a polyimide film suitable for use as a material.

  In addition, the second object of the present invention is that it is suitable for mass production without the need for pretreatment when forming the reflective layer, is lightweight and has high specularity, excellent heat resistance, heat dissipation, safety and handling, and low An object of the present invention is to provide a cost-effective and high-quality molded article, particularly a reflector base for lighting equipment and a three-dimensional wiring board.

  In order to achieve the above-mentioned object, according to the present invention, the limit measured by using Suga Test Instruments' oxygen index method flammability tester ON-2M and measuring according to JIS K7201 "Plastics-Test method for flammability by oxygen index" Oxygen index (LOI) is 33% or more, and using EXSTAR6000 DMS manufactured by SII NanoTechnology Co., Ltd., JIS-K7244-4 Plastic-Test method for dynamic mechanical properties-Part 4: Tensile vibration-Non-resonant method A polyimide film having a glass transition temperature (Tg) measured in conformity with 250 ° C. to 300 ° C. is provided.

In the polyimide film of the present invention,
Consisting of a polyimide obtained by ring-closing a polyamic acid having an average molecular weight of 450 or more in one unit;
The polyimide has a structural unit represented by the general formula (I) and / or (II),

前記一般式（Ｉ）で示される構造単位が全構成単位の５０％以上であるポリイミドからなること、および
前記一般式（ＩＩ）で示される構造単位が全構成単位の５０％以上であるポリイミドからなること
が、いずれも好ましい条件として挙げられる。

From the polyimide whose structural unit shown by the said general formula (I) is 50% or more of all the structural units, and from the polyimide whose structural unit shown by the said general formula (II) is 50% or more of all the structural units These are all preferable conditions.

  Moreover, the molded body of the present invention is characterized by using the polyimide film described above, and in particular, a reflector base for lighting equipment and a molded body having a main body portion, an outer flange portion, and an inner flange portion that form a reflective surface. A three-dimensional wiring board having a circuit pattern formed thereon is preferable.

  According to the present invention, as will be described below, it is possible to obtain a polyimide film which is excellent in flame retardancy compared to conventional ones and which can be mass-produced and is easy to perform heat extrusion molding or vacuum forming.

  Therefore, the molded article of the present invention comprising this polyimide film is particularly useful as a reflector for lighting equipment and a three-dimensional wiring board.

  The present invention is described in detail below.

  First, the polyimide film of the present invention will be described.

  The polyimide film of the present invention has a critical oxygen index of 30% or more, more preferably 35% or more, and a glass transition temperature of 250 ° C. or more and 300 ° C. or less, more preferably 260 ° C. or more and 290 ° C. or less. Features.

  If the critical oxygen index is less than 30%, the flame retardancy of the film is lowered, and if the glass transition temperature is out of the above range, the film formability is deteriorated.

  The polyimide film of the present invention is preferably made of polyimide obtained by ring-closing a polyamic acid having a unit weight average molecular weight of 490 or more. When paying attention to the chemical structure of the polyimide film, it is preferable that the structural unit represented by the above formula (I) is included, and it is more preferable that this structural unit is 50% or more of all the structural units. Other structural units are not particularly limited.

  The aromatic polyimide film of the present invention can be produced by a generally known method. For example, a polyamic acid is cast on a support in a solution state to obtain a self-supporting polyamic acid film. Then, it can manufacture by heating imidating the said polyamic acid.

  Said polyamic acid solution is obtained by polymerizing one or more diamine components and one or more tetracarboxylic dianhydrides.

  As a polymerization method of the polyamic acid solution, after the diamine compound is put in a solvent, the time required for the reaction is mixed at a ratio of 95 to 105 mol% of one or more kinds of tetracarboxylic dianhydrides with respect to the reaction components. After that, a diamine compound is further added, and then one or more kinds of tetracarboxylic dianhydrides are added and polymerized so that the total diamine component and the total tetracarboxylic dianhydride component are approximately equal. And one or more types of tetracarboxylic dianhydrides in a solvent, and after mixing for a time required for the reaction at a ratio of 95 to 105 mol% of the diamine compound with respect to the reaction components, Method of polymerizing by adding carboxylic dianhydride and then adding a diamine compound so that the total diamine component and one or more types of tetracarboxylic dianhydride components are approximately equal. Etc., and the like.

  Specific examples of the polyamic acid include diaminodiphenyl ether, 1,3 bis- (4 aminophenoxy) benzene, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 4,4′-bis (4 -Aminophenoxy) biphenyl, 1,4-bis (4-aminophenoxy) benzene, aromatic diamine components such as phenylenediamine, pyromellitic acid typified by pyromellitic dianhydride, and 3,3'- Aromatic tetracarboxylic acid compounds having two or more benzene rings such as 4,4′-biphenyltetracarboxylic acid or its dianhydride, 3,3′-4,4′-benzophenone tetracarboxylic acid or its dianhydride Can be obtained by polymerizing in a solvent to produce a thermoplastic polyimide.

  Solvents used in the above polymerization include dimethyl sulfoxide, N, N-dimethylacetamide, N, N-diethylacetamide, N, N-dimethylformamide, N, N-diethylformamide, N-methyl-2-pyrrolidone and dimethyl Examples thereof include sulfone, and these are preferably used alone or in combination.

  In general, the polyamic acid obtained by the above polymerization is adjusted so as to have a ratio of 10 to 30% by weight in the solvent.

  Next, an example of a method for obtaining a thermoplastic aromatic polyimide film from the obtained polyamic acid solution will be described.

  First, the polyamic acid solution is cast on a support using an extrusion die to obtain a self-supporting polyamic acid film. Subsequently, the end part of the obtained polyamic acid film is fixed, and a polyimide gel film is obtained by performing heat treatment at a temperature of 200 ° C. to 400 ° C.

  In this heat treatment step, biaxial stretching is preferable for improving the mechanical properties and isotropy of the polyimide film. Although it does not specifically limit about a draw ratio, It is common to draw by the magnification of 1.5 to 2.0 to the direction orthogonal to a film running direction and 1.05-1.5 in a film running direction. It is.

  Moreover, in the above, a cast means developing a polyamic acid on a support body. As an example of the cast, there is a method of extruding a polyamic acid from a bar coat, a spin coat, or a pipe-shaped substance having an arbitrary cavity shape and spreading it on a support.

  When the resulting polyamic acid was cyclized into a thermoplastic aromatic polyimide film, a chemical ring closure method using a dehydrating agent and a catalyst, a thermal ring closure method using thermal dehydration, or a combination of both were used. Any of the ring closure methods may be used.

  Examples of the dehydrating agent used in the chemical ring closure method include aliphatic acid anhydrides such as acetic anhydride and acid anhydrides such as phthalic anhydride, and these are preferably used alone or in combination. Examples of the catalyst include heterocyclic tertiary amines such as pyridine, picoline and quinoline, aliphatic tertiary amines such as triethylamine, and tertiary amines such as N, N-dimethylaniline. These are preferably used alone or in combination.

  The thickness of the polyimide film thus obtained is not particularly limited, but is preferably 25 μm to 250 μm, more preferably 75 μm to 125 μm.

  Below, according to drawing, the reflector base material for flame-retardant lighting equipment which is a molded object of this invention and the reflector for flame-retardant lighting equipment are further explained in full detail.

  FIG. 1 is a partially broken perspective view showing an example of a reflector base for lighting equipment of the present invention, and FIG. 2 is a partially broken side view showing an example of a reflector for lighting equipment of the present invention.

  In addition, the molded object in this invention means the object shape | molded by the three-dimensional shape. When this molded body is used as a base material for a reflector, it is expressed as a reflector base material, but there is no difference between them except for the limited use.

  As shown in FIG. 1, the reflector base material (flame retardant molded article) 1 for lighting equipment of the present invention has a glass transition temperature of 250 ° C. or higher and 300 ° C. or lower, and flame retardant performance of V0 in the UL94 test. The thermoplastic polyimide film having the above structure is made of a molded body obtained by hot stamping or vacuum forming, and has a main body portion 2, an outer flange portion 4 and an inner flange portion 6 that form a reflective portion. Thus, this example is configured as a lamp reflector base for an automotive headlamp.

  In the reflector base material 1 for lighting equipment, the surface smoothness of the main body 2 maintains the smoothness of the film as it is, and the projector can be used without any pretreatment before the reflective layer deposition. It has sufficient performance to obtain a reflective surface.

  When the strength of the main body 2 is a problem, it can be easily reinforced by attaching a plastic injection molding resin, a metal press part, a frame made of FRP, etc. to the outside of the main body 2. .

  In the embodiment shown in FIG. 1, the main body 2 has a simple reflecting surface shape, but any shape can be selected as long as it can be molded, for example, the main body 2 is a polyhedron. Is possible.

  2 is formed on the inner peripheral surface of the molded body 1 shown in FIG. 1 by depositing a reflective material such as aluminum by a known means. ing. In the formation process of this reflective layer 10, since the reflector base material 1 is maintaining the smoothness at the time of a film as it is, it is not necessary to perform any pretreatments, such as resin coating and degreasing.

  In addition, in the reflector 2 for lighting equipment shown in FIG. 2, the insertion port 12 of a light bulb (not shown) is opened at the center of the inner flange portion 6, and the inner flange 6 a is formed around the insertion port 12. By forming, a lamp reflector is configured.

  In the reflector base material (flame retardant molded product) 1 shown in FIG. 1, the outer flange portion 4 is molded into the final shape of the reflector 8 for lighting equipment shown in FIG. A plurality of reflector base materials 1 may be formed side by side on a film, and after vapor deposition, the outer flange portion 4 may be cut while being trimmed.

  The molded body 1 of the present invention can be obtained by molding the thermoplastic polyimide film into a desired shape by means such as hot stamping, vacuum molding, and high pressure gas spray molding. It is economically advantageous because it is simple and inexpensive, and can simultaneously mold many pieces. The vacuum forming method includes a straight method, a drape method, an air slip method, a snapback method, and a plug assist method, and any known method can be applied.

  As the metal to be deposited as a reflector on the reflector substrate (molded body) 1 for lighting equipment, aluminum or silver is most suitable from the viewpoint of reflectance, but a chemically stable metal compound should be used as appropriate. Can do. Further, chromium, nickel-chromium alloy, or the like can be used as a base for improving the adhesion strength with the reflector or film.

  As a vapor deposition means for forming the reflective layer 10, a vacuum vapor deposition method, a sputtering method, an electron beam method, an ion plating method, or the like can be used, but the present invention is not particularly limited thereto. Further, a protective film may be further formed on the obtained reflective layer 10 by coating or vapor deposition.

  The shape of the reflector 8 for lighting equipment according to the present invention may be any shape used as a headlamp or a fog lamp, and the reflective layer 10 is formed only on the reflection necessary portion of the reflector substrate 1. There may be.

  Moreover, the reflective layer 10 can be formed on the side opposite to the light bulb with respect to the reflector substrate 1, and in this case, by providing the reflective layer 10 outside the light bulb, the primary color of the thermoplastic aromatic polyimide film can be obtained. A certain yellow color can be obtained as reflected light.

  Since the molded article of the present invention is made of a specific thermoplastic aromatic polyimide film excellent in its own flame retardancy and heat resistance, its surface smoothness is good and pretreatment at the time of forming the reflective layer is not required. In addition, it can be obtained at a low cost by a simple molding method such as vacuum molding, and is extremely light and difficult to break. Therefore, it is excellent in safety and handling.

  The reflector for a molded product lighting device of the present invention has a reflective layer formed by vapor deposition on a reflector substrate made of a specific thermoplastic polyimide film molded product having excellent flame retardancy, heat resistance and surface smoothness. Because it is formed, it is not necessary to perform pretreatment such as resin coating before vapor deposition of the reflective layer, it can be obtained at low cost by mass production, and it is extremely light and difficult to break. In addition to being excellent in heat dissipation, safety and handling, it has high flame retardancy, heat resistance and specularity, and exhibits high quality performance as a lamp reflector.

  Further, the molded article of the present invention can be applied to electrical and electronic applications such as a three-dimensional wiring board by utilizing heat dissipation, safety, flame retardancy, and heat resistance.

  Next, the present invention will be specifically described by way of examples. Each characteristic of the polyimide film in an Example was evaluated with the following method.

(1) Oxygen index (LOI)
The oxygen index (LOI) indicates that the substance is burned in a mixed gas of oxygen and nitrogen, the minimum oxygen concentration is measured, and the flammability is displayed. In this example, the measurement was carried out using an oxygen index method flammability tester ON-2M manufactured by Suga Test Instruments in accordance with JIS K7201 “Plastics—Test Method for Flammability by Oxygen Index”.

(2) Glass transition temperature (Tg)
The glass transition temperature was measured according to JIS-K7244-4 plastics—Test method for dynamic mechanical properties—Part 4: Tensile vibration—Non-resonance method, using EXSTAR6000 DMS manufactured by SII Nanotechnology.

(3) Average molecular weight of 1 unit of polyamic acid Calculated from the amount of monomer added.

(4) Flame retardancy Measured according to UL94 (polymer flame retardancy test).

(5) Formability evaluation Each film was formed by using a vacuum plus pressure assist using four types of molds having different ratios of the length of a square pyramid with a constant height and h / d as shown in FIG. Comparison was made by molding. The moldability judgment criteria were: molded product height (L) / mold height (L0) = 90% or more transfer was evaluated as ◎, 80% or more transfer as ◯, and less than that as ×. However, for molding conditions,
Film preheating: Tg + 40 ° C
Molding temperature: Tg (E ") temperature Extraction temperature: Tg (E")-50 ° C
It was.

[Example 1]
In a 500 ml separable flask equipped with a DC stirrer, 17.962 of 4,4′-diaminodiphenyl ether and 159.4 g of N, N′-dimethylacetamide were placed and stirred at room temperature under a nitrogen atmosphere. 26.39 g of 3,3′-4,4′-biphenyltetracarboxylic dianhydride was added in several portions, and then 3,3′-4,4′- over 30 minutes to 1 hour. A solution in which 6% of biphenyltetracarboxylic dianhydride was uniformly dispersed in N, N′-dimethylacetamide was added in several portions, and the viscosity of the polyamic acid was adjusted to 2500 poise.

  A part of the obtained polyamic acid was cast on a glass plate, and a uniform film was formed using a bar coater. This was treated at 100 ° C. for 20 minutes, peeled off from the glass plate, fixed to a metal frame, and heat treated at 200 ° C. for 30 minutes and 300 ° C. for 20 minutes to obtain a thermoplastic aromatic polyimide film. Table 1 shows the results of evaluating the oxygen index, glass transition temperature, flame retardancy and moldability of this molded product.

[Example 2]
In a 500 ml separable flask equipped with a DC stirrer, 17.66 of 4,4′-diaminodiphenyl ether and 159.4 g of N, N′-dimethylacetamide were placed and stirred at room temperature under a nitrogen atmosphere. Next, 14.28 g of 3,3′-4,4′-biphenyltetracarboxylic dianhydride was added in several portions, and then pyromellitic dianhydride 12.30 g after 30 minutes to 1 hour. 12 g was added in several batches, and then 30 minutes to 1 hour later, 3,3′-4,4′-biphenyltetracarboxylic dianhydride was added to 6% of N, N′-dimethylacetamide. The solution in which pyromellitic dianhydride was dissolved was added in several times, and the viscosity of the polyamic acid was adjusted to 2500 poise.

  A part of the obtained polyamic acid was cast on a glass plate, and a uniform film was formed using a bar coater. This was treated at 100 ° C. for 20 minutes, peeled off from the glass plate, fixed to a metal frame, and heat treated at 200 ° C. for 30 minutes and 300 ° C. for 20 minutes to obtain a thermoplastic aromatic polyimide film. Table 1 shows the results of evaluating the oxygen index, glass transition temperature, flame retardancy and moldability of this molded product.

[Example 3]
In a 500 ml separable flask equipped with a DC stirrer, 15.56 g of 3,4'-diaminodiphenyl ether and 159.4 g of N, N'-dimethylacetamide were placed and stirred at room temperature under a nitrogen atmosphere. 24.29 g of 3,4,3,4'-benzophenonetetracarboxylic acid was charged in several portions, and then 3,4,3,4'-benzophenonetetracarboxylic acid dicarboxylate was added from 30 minutes to 1 hour later. A solution of 6% 3,4,3,4′-benzophenonetetracarboxylic acid dissolved in N, N′-dimethylacetamide was added in several portions to adjust the viscosity of polyamic acid to 2500 poise. .

  A part of the obtained polyamic acid was cast on a glass plate, and a uniform film was formed using a bar coater. This was treated at 100 ° C. for 20 minutes, peeled off from the glass plate, fixed to a metal frame, and heat treated at 200 ° C. for 30 minutes and 300 ° C. for 20 minutes to obtain a thermoplastic aromatic polyimide film. Table 1 shows the results of evaluating the oxygen index, glass transition temperature, flame retardancy and moldability of this molded product.

[Example 4]
In a 500 ml separable flask equipped with a DC stirrer, 15.56 g of 4,4′-diaminodiphenyl ether and 159.4 g of N, N′-dimethylacetamide were placed and stirred at room temperature under a nitrogen atmosphere. 24.29 g of 3,4,3,4'-benzophenonetetracarboxylic dianhydride was added in several portions, and then 3,4,3,4'-benzophenonetetrahydrate was added from 30 minutes to 1 hour later. A solution in which 6% of 3,4,3,4'-benzophenonetetracarboxylic dianhydride was dissolved in N, N′-dimethylacetamide was added in several portions, and the polyamic acid The viscosity was adjusted to 2500 poise.

  A part of the obtained polyamic acid was cast on a glass plate, and a uniform film was formed using a bar coater. This was treated at 100 ° C. for 20 minutes, peeled off from the glass plate, fixed to a metal frame, and heat treated at 200 ° C. for 30 minutes and 300 ° C. for 20 minutes to obtain a thermoplastic aromatic polyimide film. Table 1 shows the results of evaluating the oxygen index, glass transition temperature, flame retardancy and moldability of this molded product.

[Comparative Example 1]
In a 500 ml separable flask equipped with a DC stirrer, 24.87 g of 2,2′-bis [4- (4-aminophenoxy) phenyl] propane and 159.4 g of N, N′-dimethylacetamide were placed under a nitrogen atmosphere. And stirred at room temperature. 7.81 g of 3,4,3,4'-benzophenonetetracarboxylic acid was added in several portions, then 7.53 g of pyromellitic dianhydride was added several times over 30 minutes to 1 hour later. Then, 3,4,3,4'-benzophenone tetracarboxylic dianhydride was added to 6% 3,4,3,4'-benzophenone tetracarboxylic acid in N, N'-dimethylacetamide. The dissolved solution was added in several times, and the viscosity of the polyamic acid was adjusted to 2500 poise.

  A part of the obtained polyamic acid was cast on a glass plate, and a uniform film was formed using a bar coater. This was treated at 100 ° C. for 20 minutes, peeled off from the glass plate, fixed to a metal frame, and heat treated at 200 ° C. for 30 minutes and 300 ° C. for 20 minutes to obtain a thermoplastic aromatic polyimide film. Table 1 shows the results of evaluating the oxygen index, glass transition temperature, flame retardancy and moldability of this molded product.

[Comparative Example 2]
In a 500 ml separable flask equipped with a DC stirrer, 19.43 g of 4,4′-diaminophenyl ether and 159.4 g of N, N′-dimethylacetamide were placed and stirred at room temperature under a nitrogen atmosphere. 9.24 g of pyromellitic dianhydride was added in several batches, and then a solution of 6% pyromellitic dianhydride in N, N'-dimethylacetamide was added in several batches. The viscosity of the polyamic acid was adjusted to 2500 poise.

  A part of the obtained polyamic acid was cast on a glass plate, and a uniform film was formed using a bar coater. This was treated at 100 ° C. for 20 minutes, peeled off from the glass plate, fixed to a metal frame, and heat treated at 200 ° C. for 30 minutes and 300 ° C. for 20 minutes to obtain a thermoplastic aromatic polyimide film. Table 1 shows the results of evaluating the oxygen index, glass transition temperature, flame retardancy and moldability of this molded product.

  The molded body of the present invention, particularly the reflector for flame retardant lighting equipment, is a reflector base material comprising a molded body of a specific thermoplastic aromatic polyimide film excellent in its own flame retardancy, heat resistance and surface smoothness. Since a reflective layer is formed on the top by vapor deposition, there is no need to perform pre-treatment such as resin coating before vapor deposition of the reflective layer, and it can be obtained at low cost by mass production. Because it does not cause degassing that impedes practical use when the lamp is lit, it not only has excellent heat dissipation, safety and handling, but also has high flame retardancy, heat resistance and specularity, and exhibits high quality performance Therefore, it can be advantageously used as a lamp reflector for an automobile headlamp, fog lamp, large projector or the like.

FIG. 1 is a partially broken perspective view showing an example of a molded body (reflector base material for lighting equipment) of the present invention. FIG. 2 is a partially broken side view showing an example of the molded body (reflector for lighting equipment) of the present invention. FIG. 3 is a mold model diagram for formability evaluation.

Explanation of symbols

1 Molded body (reflector base material for lighting equipment)
2 Body part 4 Outer flange part 6 Inner flange part 6a Inner flange 8 Reflector 10 for lighting equipment Reflective layer 12 Bulb insertion port

Claims (8)

The limit oxygen index (LOI) measured according to JIS K7201 “Plastic-Test method for flammability by oxygen index” using Suga Test Instruments' oxygen index method flammability tester ON-2M is 33% or more, In addition, using EXSTAR6000 DMS manufactured by SII NanoTechnology Co., Ltd., JIS-K7244-4 Plastics-Test method for dynamic mechanical properties-Part 4: Tensile vibration-Glass transition temperature (Tg) measured according to non-resonance method is 250 A polyimide film having a temperature of from ℃ to 300 ℃. The polyimide film according to claim 1, comprising a polyimide obtained by ring-closing a polyamic acid having an average molecular weight of 450 or more per unit. The polyimide film according to claim 1, wherein the polyimide has a structural unit represented by general formula (I) and / or (II).

The polyimide film according to any one of claims 1 to 3, wherein the structural unit represented by the general formula (I) is made of polyimide having 50% or more of all structural units. The polyimide film according to any one of claims 1 to 3, wherein the structural unit represented by the general formula (II) is made of polyimide having 50% or more of all structural units. The molded object using the polyimide film of any one of Claims 1-5. The molded body according to claim 6, which is a reflector base for lighting equipment having a main body portion, an outer flange portion, and an inner flange portion that form a reflecting surface. The molded body according to claim 6, which is a three-dimensional wiring board formed by forming a circuit pattern on the molded body.

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