JP2000256476A - Resin composition, molding, and electronic component made by using same and suited for surface mounting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin composition which has improved flow properties and can give a molding improved in mechanical properties and heat resistance by making the composition include a polyimide based on a semi-aliphatic pyromellitimide structure with a fibrous filler. SOLUTION: A polyamic acid obtained by reacting a tetracarboxylic dianhydride with a diamine in a solvent is chemically cyclized with acetic anhydride and pyridine to obtain a polyimide based on a semialiphatic pyromellitimide structure of the formula and having a melt viscosity of 0.3-15 (as measured in a solution prepared by dissolving 50 mg of the resin in 10 ml of a mixed solvent comprising tetrachloroethane and phenol in a volume ratio of 6:4 at 35 deg.C). This polyimide is compounded with 1-70 wt.%, desirably, 25-60 wt.% fibrous filler, and, optionally, additives such as a filler, a heat stabilizer, an antioxidant, a light stabilizer, an ultraviolet absorber, a lubricant, a pigment, a flame retardant, flame retardant aid, a plasticizer, and a nucleator to obtain a resin composition which can give a molding having a heat distortion temperature of 250 deg.C or above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a resin composition comprising a specific polyimide. More specifically, the present invention relates to a heat-resistant polyimide composition which can be used for a surface-mountable electronic component, a molded product thereof, and an electronic component using the same.

[0002]

2. Description of the Related Art In the field of electronic components, with the recent trend toward miniaturization and high performance of electric appliances and to improve productivity, as a method of mounting various electronic components on a substrate, the mounting density of components is high and the efficiency is high. Good surface mount technology (SMT) is spreading. In response to the surface mounting method using this surface mounting technology, as electronic components have become smaller and thinner, resin materials must also be improved in mechanical strength and fluidity during molding. became.

Further, in the surface mounting method, electronic components such as connectors are heated from the upper and lower parts by a soldering method by heating in a reflow furnace, so that the temperature is more severe than in the conventional mounting method. You will be exposed to the conditions.

As a result, resin materials for electronic components are required to be further improved in heat resistance. For example, polyamide resins such as nylon-6 resin and nylon-6,6 resin, and polyethylene terephthalate and polybutylene terephthalate. Conventional materials such as polyester resin have insufficient heat resistance.

Therefore, application of polyphenylene sulfide resin, aromatic polyamide resin and the like as a resin material for the electronic component for surface mounting has been studied. These resins are excellent in heat resistance, but have the above-mentioned mechanical properties and fluidity. Due to such disadvantages, there are great restrictions on industrial use.

[0006] The resin composition having such excellent mechanical properties, flow properties, and heat resistance is used for various trays, food heating trays, towels, containers for heating and transporting towels, baskets, various tableware, Even in heat-resistant container applications such as ashtrays, there is a strong need as a molding material because it is desirable from the viewpoint of expanding applications and improving productivity.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a resin composition having excellent mechanical properties, flow properties and heat resistance, which is obtained by mixing a crystalline semi-aromatic polyimide and a fibrous filler. That is. A further object of the present invention is to provide a surface-mountable electronic component using the resin composition. An additional object of the present invention is to provide a molded article obtained by molding the resin composition.

[0008]

The polyimide used in the present invention has the following formula (1)

[0009]

Embedded image

This is a crystalline semi-aliphatic polyimide containing a pyromellitic imide structure as a main component. Specifically, the present invention is as follows. 1. A resin composition obtained by mixing a polyimide containing a semi-aliphatic pyromellitic imide structure represented by the following formula (1) as a main component and a fibrous filler.

[0011]

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2. 2. The resin composition according to the above item 1, wherein the fibrous filler is contained in a range from 70% by weight to 1% by weight based on the whole resin composition. 3. 3. The resin composition according to the above 1 or 2, wherein the fibrous filler is a glass fiber. 4. 4. The resin composition according to any one of the above 1 to 3, wherein the heat deformation temperature is 250 ° C or higher. 5. A molded article obtained by molding the resin composition according to any one of the above 1 to 4. 6. An electronic component for surface mounting, comprising the resin composition according to any one of 1 to 4 above. Here, "semi-aliphatic" means that all or a part of the diamine component and / or a part of the tetracarboxylic acid component are aliphatic.

In the polyimide, the copolymerization component may be contained as a diamine component, a tetracarboxylic acid component, or a mixture of both, but is not limited thereto. .

As the substance used to obtain the diamine component structure of the above formula (1), dodecanediamine can be used, and as the substance used to obtain the tetracarboxylic acid component structure, pyromellitic dianhydride can be used.

As diamine components to be copolymerized, ethylene diamine, propylene diamine, butane diamine, pentane diamine, hexane diamine, octane diamine,
Nonanediamine, decanediamine, undecanediamine, alkylenediamines such as tetramethylhexanediamine, 1,12- (4,9-dioxa) dodecanediamine, 1,8- (3,6-dioxa) octanediamine, Jeffamine and the like Aliphatic diamino ethers,
Diamines containing alicyclic hydrocarbons such as cyclohexanediamine and isophoronediamine are exemplified.

As the tetracarboxylic acid component to be copolymerized, an acid component derived from an aromatic tetracarboxylic dianhydride or an aliphatic tetracarboxylic dianhydride can be used. For example, benzophenonetetracarboxylic dianhydride, biphenyltetracarboxylic dianhydride, bis (dicarboxyphenyl) propane dianhydride, 4,4 ′
-[2,2,2- (trifluoromethyl) ethylidene]
Bis (1,2-benzenedicarboxylic acid) dianhydride, bis (dicarboxyphenyl) sulfonic dianhydride, bis (dicarboxyphenyl) ether dianhydride, thiophenetetracarboxylic dianhydride, naphthalenetetracarboxylic dianhydride Anhydride, 1,2,3,4-butanetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, 5 (2,5-dioxotetrahydrofuryl) 3-methyl-3-cyclohexene-1,2 And tetracarboxylic acid components derived from dicarboxylic dianhydrides.

The copolymerization ratio is not particularly specified, but any copolymerization ratio lower than 50 mol% can be used.
Even more desirable is a ratio lower than 30 mol%. However, if the melting point of the obtained polyimide is lower than 250 ° C., it cannot be used for surface mounting, so it is preferable to carry out copolymerization with a component having a larger amount of dodecanepyromellitimide component. Here, the dodecanepyromellitimide component is a component having the structure of the formula (1).

As the polyimide resin used in the present invention, any resin produced by any method such as melt polymerization, solution polymerization, solid phase polymerization, and interfacial polymerization can be used. 1) a method in which a polyamic acid produced by reacting tetracarboxylic dianhydride and a diamine in a solvent is chemically closed using acetic anhydride and pyridine, or (2) a thermal dehydration cyclization of the polyamic acid. Method,
(3) A method of heating and dehydrating and polymerizing tetracarboxylic dianhydride and diisocyanate, and (4) a method of reacting a dicarboxylic or diester of tetracarboxylic acid with a diamine to effect dealcoholization and cyclization.

The molecular weight of the polyimide used in the present invention is not particularly limited, but from the viewpoint of moldability, ηsp / C is 0.1.
Preferably, the solution viscosity ranges from 3 to 15. The solution viscosity is a value measured at 35 ° C. by dissolving 50 mg of the resin in 10 ml of a mixed solvent of tetrachloroethane and phenol mixed at a volume ratio of 6: 4.

The polyimide of the present invention may have its terminal blocked, and examples of the terminal blocking agent include phthalimide derivatives, monoamine derivatives, alcohols, and the like. it can.

The fibrous filler used in the composition of the present invention is mixed for the purpose of improving mechanical strength and imparting heat resistance.

As such a fibrous filler, organic,
Various solid materials can be used regardless of the inorganic material. By using the fibrous material, the heat distortion temperature of the resin composition can be significantly improved, and high heat distortion heat resistance can be imparted.

Examples of such a fibrous filler include glass fiber, metal fiber, aramid fiber, ceramic fiber,
Examples thereof include potassium titanate whiskers, carbon fibers, and asbestos. Particularly, it is preferable to use glass fiber because it is economically excellent and has excellent heat resistance.

These fibrous fillers can be used in an appropriate amount for imparting heat resistance and strength. However, if the amount is too small, sufficient strength cannot be obtained, and if the amount is too large, moldability decreases. Therefore, it can be used in an amount of 1% by weight to 70% by weight based on the whole resin composition. More preferably between 25% and 60% by weight.

The mixing of the polyimide and the fibrous filler according to the present invention can be carried out by any method as long as it is via a molten state. For example, a method of mixing using a ruder or a method of melt-kneading in a melting pot can be adopted.

The heat distortion temperature of the resin composition obtained in the present invention is preferably higher than 250 ° C., and if it is lower than this, it is difficult to use it suitably for heat-resistant applications. For example, an electronic component considering solder reflow or the like can be suitably used as long as it has a heat deformation temperature exceeding 250 ° C.

The resin composition of the present invention may contain various non-fibrous additives as necessary. Examples of the additives that can be preferably used include various fillers such as talc, calcium carbonate, mica, clay, titanium oxide, aluminum oxide, glass flakes, metal flakes, metal powders, and phosphate esters and phosphite esters. Heat stabilizers or oxidation stabilizers, light stabilizers, ultraviolet absorbers, lubricants, pigments, flame retardants,
Examples include flame retardant aids, plasticizers, and crystal nucleating agents.

The resin composition of the present invention can be suitably used by molding it into, for example, electronic components for surface mounting, heat-resistant containers, filaments and the like. Here, the electronic component for surface mounting refers to an electronic component that is soldered on a substrate by a surface mounting method.

Here, the surface mounting method refers to a method for mounting an electronic component on a wiring board by passing leads of the electronic component from a through hole of the board and directly soldering to a surface opposite to a surface on which the electronic component is mounted ( In contrast to the conventional insertion mounting that performs flow soldering or wave soldering, electronic components are placed on solder printed on the wiring board,
This is a method of fixing the electronic component by melting the solder by passing the substrate together with a heating furnace called a reflow furnace.

Various advantages can be produced by this surface mounting method, such as an increase in mounting density, mounting on both front and back surfaces, and a reduction in cost by improving efficiency. With the trend of shorter size, higher function, lower price, etc., soldering methods are becoming the mainstream, and the application field is camera integrated VT
R, calculators, cameras, clocks, LCD televisions, electronic games, personal computers, PC cards and other consumer electronic devices, minicomputers,
Office computers, workstations, peripherals, terminal devices,
It has spread to industrial electronic equipment such as measurement equipment, and further to aerospace equipment.

As a method of heating a substrate in a reflow furnace in surface mounting, a heat conduction system in which the substrate is placed on a heat-resistant belt moving on a heater and heated, and the boiling point is about 220 ° C.
VPS system utilizing latent heat during coagulation of fluorine-based liquid,
Hot air convection heat transfer method that passes the substrate through the place where hot air is forcibly circulated, far infrared method that heats the substrate from above or from both upper and lower surfaces with far infrared, and heating with hot air and heating with far infrared Although there are methods to be used, a far-infrared ray method and a hot air convection heat transfer method are often adopted for reasons such as running costs. In these heating methods, unlike the conventional insertion mounting method, the components to be mounted are also heated to a temperature not lower than the solder melting temperature, which is a very severe condition for the resin material used for the electronic components.

Specific examples of these surface-mountable electronic components include various connectors, switches, relays, coil bobbins, volumes, sockets, plug boards, terminal blocks,
Sensors, resistors, transformers, main bodies such as ICs (integrated circuits), or mainly housings (cases, bodies, covers), frames, electrical insulators, slides (sliders), bases, wafers, lens cams, spools, cards, and yokes And the like are typical examples.

The present invention is directed to a resin electronic component mounted on a substrate by such a surface mounting method. Among them, the connector may be any of a wire-to-wire (relay) connector, a wire-to-board connector, a board-to-board connector, and the like, and may be an FFC (Fle).
xixable Flat Cable) / FPC (Fle
xiprinted Circuit), SIMM socket, ROM socket, interface connector, board-in connector, jumper wire connector, and other types of connectors, including straight type, right angle type, multi-harness type, and injector type. Any of a trever type, a clip mounting type, a bottom entry type, a strain relief and the like may be used, and the connection form may be any of a stack connection, a horizontal connection, and a vertical connection.

Further, the heat-resistant container which is one of the molded articles of the present invention includes various trays, food heating trays, towels,
Heat-resistant containers represented by containers for heating and transporting towels, baskets, various dishes, ashtrays, and the like. However, the molded article is not limited to this, and can be used for applications requiring heat resistance to hot water washing, steam sterilization, and the like.

The above-mentioned surface-mountable parts and containers can be obtained very easily by employing the molding method used for general thermoplastic resins, for example, injection molding, of the resin composition of the present invention. Examples will be described below.

[0036]

[Example 1] NMP 3L and toluene 500m
Then, 2 mol of dodecanediamine was dissolved in a mixed solvent with 1 and 2 mol of pyromellitic anhydride was added thereto under a nitrogen stream, and the mixture was gradually heated from room temperature. At a temperature of 140 ° C. to 165 ° C., azeotropy between toluene and water generated by the reaction starts, and the reaction is completed in about 3 hours to obtain powdered polydodecanepyromellitimide (ηsp / C = 1.3). . 60 parts by weight of a crushed chip obtained by melting this and glass fiber (Glass chopped strand made by Asahi Fiberglass) 4
0 parts by weight, and molded by an injection molding machine at a cylinder temperature of 280 to 320 ° C. and a mold temperature of 40 ° C.
A plate-shaped molded body of 0 mm × 12 mm × 3 mm was obtained. The molding was easy and the molded product had a good shape. The heat distortion temperature (18.5 kgf load) of this molded product measured according to JIS C2241 was over 300 ° C. Also, it had excellent mechanical properties.

Example 2 3 L of NMP and 500 of toluene
21.8 mol of dodecanediamine and 0.2 mol of decanediamine were dissolved in a mixed solvent with 2 ml of the mixture, and 2 mol of pyromellitic anhydride was added thereto under a nitrogen stream, and the mixture was gradually heated from room temperature. At a temperature of 140 ° C. to 165 ° C., azeotropy between toluene and water generated by the reaction started, and the reaction was completed in about 3 hours to obtain a powdery polyimide (ηsp / C = 1.33). 60 parts by weight of a crushed chip obtained by dissolving this and 40 parts by weight of glass fiber (Glass Ron chopped strand made by Asahi Fiber Glass) are mixed, and the cylinder temperature is changed from 320 ° C. to 280 ° C. and the mold temperature is 40 ° C. by an injection molding machine. To obtain a plate-shaped molded body of 120 mm × 12 mm × 3 mm. The molding was easy and the molded product had a good shape. The heat distortion temperature (18.5 Kgf) of this molded body measured by the measurement method according to JIS C2241.
Load) was 280 ° C. Also, it had excellent mechanical properties.

[0038]

According to the present invention, it is possible to obtain a resin composition having excellent heat resistance and a surface-mounted electronic component made of the resin composition.

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Claims (6)

[Claims] 1. A resin composition obtained by mixing a polyimide having a semi-aliphatic pyromellitic imide structure represented by the following formula (1) as a main component and a fibrous filler. Embedded image 2. The resin composition according to claim 1, wherein the fibrous filler is contained in a range from 70% by weight to 1% by weight based on the whole resin composition. 3. The resin composition according to claim 1, wherein the fibrous filler is glass fiber. 4. The resin composition according to claim 1, wherein the heat deformation temperature is 250 ° C. or higher. 5. A molded article obtained by molding the resin composition according to claim 1. 6. A surface-mountable electronic component using the resin composition according to claim 1.