JPH08100120A - Resin composition and electronic part produced therefrom - Google Patents

Abstract

PURPOSE: To obtain an electronic part composed of a nylon 46 resin composition, having reduced water absorbency and excellent in reflow solderability. CONSTITUTION: This resin composition is obtained by compounding 60-90 wt.% of a mixture of (A) a nylon 46 resin and (B) a polybutylene terephthalate resin and (C) 10-40wt.% of glass fibers, wherein the weight ratio of the component (B) in the total of the components (A) and (B) is 0.10-0.40. The composition is suitable for an electric part for surface use.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition, and more specifically, a resin composition for surface mount electronic parts made of glass fiber reinforced polytetramethylene adipamide (nylon 46), which exhibits excellent reflow solderability, And a surface-mountable electronic component made of the same.

[0002]

2. Description of the Related Art In the field of electronic parts, with the recent miniaturization and high performance of electric appliances, aiming at improving productivity, etc., various electronic parts are mounted on a board as parts. The surface mounting method (S
The MT method) is spreading. Therefore, for the resin material for electronic parts corresponding thereto, improvement in mechanical strength and fluidity at the time of molding is required for downsizing and thinning. Furthermore, since this surface mounting method is a soldering method by heating far infrared rays in a reflow furnace, it is heated from above the electronic component material such as the connector, and the temperature is more severe than the conventional mounting method. It becomes a condition.

That is, it is required to improve heat resistance of resin materials for electronic parts corresponding to them, and polyamide resins such as nylon 6 resin and nylon 66 resin, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, etc. Conventional materials lack heat resistance.

The application of polyphenylene sulfide resin, aromatic polyamide resin, or the like as a resin material for the surface mountable electronic parts has been examined. Although these resins have excellent heat resistance, they have the above-mentioned mechanical characteristics and fluidity. However, there is a drawback in that the industrial use is limited.

As described above, there is a strong demand in this field for a resin material for surface-mountable electronic parts having excellent mechanical properties, flow properties and heat resistance.

Nylon 46 resin has attracted attention as a material that can meet this demand. Nylon 46 resin is a resin obtained from tetramethylene diamine or its functional derivative and adipic acid or its functional derivative, and has excellent heat resistance, and also has good mechanical properties such as tensile strength and bending strength and flow characteristics. Because it is excellent, it is considered to have great utility value as a useful engineering plastic.

However, this nylon 46 resin has a drawback that it has a higher water absorption rate because it has a higher proportion of amide groups than ordinary polyamide resins such as nylon 6 resin and nylon 66 resin. This means that nylon 46 resin has better heat resistance and mechanical properties than general polyamide resin in the dry state immediately after molding, but nylon 46 resin loses its superiority in actual use. .

Furthermore, when mounting on a substrate by the surface mounting method using the above-mentioned reflow furnace, the electronic parts made of nylon 46 resin in a dry state exhibit heat resistance,
In the water-absorbed state, damage called so-called blistering may appear on the surface of the component in some cases, and the value of the component is significantly reduced, so that the condition range of the surface mounting method is narrowed. In other words, electronic components made of nylon 46 resin have poor reflow solderability due to the defects in the water absorption characteristics of nylon 46 resin, and it is important to utilize the excellent heat resistance of this resin as a material for surface mount compatible electronic components. It is an obstacle.

Attempts have been made to blend other non-water-absorbent resins in order to improve the water absorption of nylon 46 resin, for example, to improve the properties by combining nylon 46 resin with polyphenylene sulfide resin or aromatic polyester resin. (JP-A-3-263461, 4-292655, 5-
(See JP 239344).

However, improvement of reflow solderability by improving water absorption in a non-flame retardant system has not been sufficiently studied.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances. The object is to improve a nylon 46 resin composition as a surface mount electronic component material exhibiting excellent reflow solderability, and to provide a surface mount electronic component having an excellent function.

[0012]

The present inventors have conducted extensive studies to improve the reflow resistance of nylon 46 resin. As a result, a composition obtained by blending nylon 46 resin with a specific amount of a specific polymer and glass fiber meets the above-mentioned object. Then, they have found that they can provide surface mountable electronic components, and have reached the present invention.

That is, the resin composition of the present invention comprises (A) nylon 46 resin and (B) polybutylene terephthalate resin in a total amount of 60 to 90% by weight and (C) glass fiber of 10 to 40% by weight, Further, it is a resin composition in which the weight ratio of the component (B) in the total amount of the component (A) and the component (B) is in the range of 0.10 to 0.40, and an electronic component comprising the resin composition.

The present invention is described in detail below.

Component (A) nylon used in the present invention
46 A resin is mainly a polyamide obtained by a condensation reaction using adipic acid or a functional derivative thereof as an acid component and tetramethylenediamine or a functional derivative thereof as an amino component. A part of the diamine component may be replaced with another copolymerization component.

The nylon 46 resin used in the present invention has an intrinsic viscosity of 0.90 to 1.90 when measured at 35 ° C. with m-cresol in an electronic component, and further from 1.10 to
It is desirable to be in the range of 1.50.

When nylon 46 resin having an intrinsic viscosity of more than 1.90 is used, the fluidity during molding of electronic parts is poor, and the glossiness of the appearance of the obtained electronic parts is lost, as well as its mechanical properties, It is not preferable because the dispersion of thermal characteristics becomes large. On the other hand, when the intrinsic viscosity number is lower than 0.90, the mechanical strength of electronic parts is reduced.

The component (B) polybutylene terephthalate resin used in the present invention is an aromatic polyester obtained by a condensation reaction using terephthalic acid as its acid component and tetramethylene glycol as the diol component.

The blending amount of the component (B) polybutylene terephthalate is such that the weight ratio in the total amount of the component (A) and the nylon 46 resin is in the range of 0.10 to 0.40. This ratio is 0.10
When it is less than 0.40, the effect of improving the reflow solderability by improving the water absorption of the composition is not sufficient, and when it is more than 0.40, the mechanical properties of the composition are deteriorated, which is not preferable.

When polybutylene terephthalate is blended with nylon 46 resin, the water absorption of polybutylene terephthalate is extremely smaller than that of nylon 46 resin, and the water absorption of the composition is lowered. However, since the compatibility between nylon 46 resin and polybutylene terephthalate is poor, a composition obtained by simply kneading both is remarkably inferior in mechanical properties and is not suitable for practical use.

It is already known that when a phenoxy resin is added to this composition, the compatibility of nylon 46 resin and polybutylene terephthalate is improved and the mechanical properties are improved (see Japanese Patent Laid-Open No. 3-79664). In this improvement, the glass is blended in place of the phenoxy resin to further improve the mechanical properties without compatibilizing agents as compared with the conventional composition, and at the same time, to impart excellent reflow solderability.

The glass fiber of the component (C) used in the present invention is not particularly limited as long as it is generally used for reinforcing a resin. For example, long fiber type (glass roving)
And chopped strands in the form of short fibers, milled fibers and the like can be used.

The blending amount of glass fiber is 10 to 10 in the resin composition.
40% by weight. If the amount is less than 10% by weight, the effect of improving the mechanical strength and heat resistance of the molded product is not sufficient. Also
If it exceeds 40% by weight, the fluidity of the composition in the molten state becomes extremely poor, so that a molded article having a good appearance cannot be obtained, and strength is saturated, which is not preferable.

The resin composition of the present invention may be blended with a pigment or other compounding agent, if necessary. Examples of the compounding agent include fillers, for example, aramid fibers other than glass fibers, carbon fibers, steel fibers, glass flakes and the like powdery, granular or plate-like inorganic fillers.

Further, for the purpose of improving heat resistance, an antioxidant or a heat stabilizer such as a copper compound such as copper iodide, a hindered phenol compound, an aromatic amine compound, an organic phosphorus compound or a sulfur compound may be added. . Various epoxy compounds, oxazoline compounds and the like may be added for the purpose of improving melt viscosity stability and hydrolysis resistance.

Other stabilizers, colorants, lubricants, UV absorbers and antistatic agents can also be added.

To obtain the resin composition according to the present invention, known compounding methods can be used. Usually, it is preferable to uniformly disperse these blending components, and a method in which all or part of them are simultaneously or separately mixed with a mixer such as a blender, a kneader, a Panbury mixer, a roll, an extruder or the like to homogenize them. be able to. Furthermore, there is a method in which a composition that has been dry-blended in advance is melt-kneaded by a heated extruder to homogenize it, then extruded into a wire shape, and then cut into a desired length to granulate.

The resin composition obtained by the present invention can be molded very easily by a usual method using a general thermoplastic resin molding machine.

The electronic component of the present invention is intended to be a component which is manufactured by the surface mounting method (SMT method) when soldering on a substrate.

The surface mounting method is a method for mounting an electronic component on a wiring board, in contrast to a conventional insertion mounting method in which the through hole of the board is directly soldered to the surface opposite to the surface on which the electronic component is mounted. This is a method in which an electronic component is placed on a printed and printed solder on a substrate and the whole substrate is passed through a heating furnace called a reflow furnace to melt the solder and fix the electronic component. According to this surface mounting method, mounting density can be increased, both front and back surfaces can be mounted, and various advantages such as efficiency can be achieved and cost can be reduced. Therefore, the soldering method is becoming the mainstream in light of the recent trend toward lighter, thinner, shorter, smaller, higher-performance, and lower-priced electronic devices, and its application fields are camera-integrated VTRs, calculators,
Consumer electronic devices such as cameras, watches, LCD TVs, electronic games, handheld computers, computers, office computers,
Workstations, personal computers, peripherals, end devices,
Industrial electronic equipment such as measuring instruments, as well as aerospace equipment.

As a method of heating the substrate in the reflow furnace in the surface mounting, a heat conduction system in which the substrate is placed on a heat-resistant belt moving on a heater and heated, and a boiling point is about 220
VPS method that uses latent heat at the time of coagulation of fluorine liquid at ℃
Uses hot air convection heat transfer method in which hot air is forcedly circulated through the substrate, far infrared ray method in which far infrared rays heat the substrate from above or from both sides, and heating by hot air and far infrared rays are used in combination There are various methods, such as a method that uses far infrared rays and hot air in combination for the reason of running cost. In these heating methods, unlike the conventional insertion mounting method, the mounted component is also heated to the solder melting temperature, which is a very severe condition for the resin material used for the electronic component.

Specific examples of these surface-mountable electronic parts include connectors, switches, volumes, capacitor cases, ICs, relays, resistors, LEDs, and other parts, and body parts and cases made of resin. However, the present invention is not limited to these, and is intended for resin electronic components mounted on a substrate by a surface mounting method.

[0033]

EXAMPLES The present invention will be described in detail below with reference to examples. In addition,
Various properties in the examples were measured by the following methods.

(1) Mechanical strength: tensile test is ASTM D638
The impact test complies with ASTM D256 (with Izod and notch).

(2) Water absorption characteristics: Constant temperature and humidity device ("EC-10M
HHP "manufactured by Hitachi, Ltd.), when each molded product was carefully arranged in an atmosphere with a relative humidity of 85% at 85 ° C for 1 hour and left in water at 23 ° C for 15 hours. Calculated from the weight increase compared to when

[Examples 1-2 and Comparative Examples 1-2] 110
Nylon 46 resin ("STANYL" manufactured by DSM of the Netherlands) with an intrinsic viscosity of 1.34 and polybutylene terephthalate (PBT resin TRB-H Teijin Ltd.) dried for 12 hours under reduced pressure of 1.3 kPa at ℃
And a glass fiber chopped strand (made by Nippon Electric Glass Co., Ltd.) having a diameter of 10.5 μm and a length of 3 mm at a ratio shown in Table 1 in advance by a tumbler to uniformly mix them, and then a vent with a screw diameter of 44 mm each Using a twin-screw extruder to draw a vacuum, cylinder temperature 320 ℃, screw speed 160r
It was melted and kneaded at a discharge rate of 35 kg / h and a thread discharged from the die was cooled and cut to obtain pellets for molding.

Then, the pellets were used in an injection molding machine with an injection capacity of 5 ounces to obtain a cylinder temperature of 300 ° C. and a mold temperature.
A molded product for each characteristic measurement was molded under the conditions of 120 ° C., injection pressure 800 Kg / cm ² , cooling time 15 seconds, and total molding cycle 40 seconds.

For testing the solder resistance when used as an electronic component, pellets having the composition shown in Table 1 prepared by the above method were used to form a cylinder in an injection molding machine having an injection capacity of 1.5 ounces. Temperature 300 ℃, mold temperature 120 ℃, injection pressure 670Kg / cm ² , cooling time 6 seconds, and total molding cycle 15
A condenser case cover having a diameter of 4 mm was molded under the condition of seconds.

The molded articles were subjected to relative humidity at 85 ° C.
Leave in an atmosphere of 85% for 1 hour and in water at 23 ° C
By controlling the humidity for 15 hours, water absorption was promoted to obtain a water-absorbed molded article.

The reflow soldering resistance test of the molded articles composed of the various compositions obtained by the above method was carried out by a reflow furnace using hot air and far infrared rays (manufactured by Asahi Engineering Co., Ltd.). The heating temperature pattern was set so that it was preheated at 150 ° C. for 60 seconds and then heated at a desired temperature for 20 seconds, and the reflow soldering temperature was determined by measuring the surface temperature of the substrate with a thermocouple. The reflow soldering resistance was evaluated by the presence or absence of blisters on the surface of the molded product after heating in a reflow furnace.

The results are also shown in Table 1.

[0042]

[Table 1]

Molded articles made of glass fiber reinforced nylon 46 resin have excellent reflow solderability,
In the water absorption state, the soldering temperature is lower than that in the absolutely dry state and reaches about 262 ° C. (Comparative Example 1).

However, the molded product made of the composition containing the PBT resin suppresses the deterioration of the reflow soldering property in the water absorbing state, and becomes a composition having excellent soldering resistance (Example 1). Further, even if the humidity control conditions are strict, its superiority does not change (Example 2 and Comparative Example 2).

[Comparative Example 3] Nylon 46 resin and PBT resin each containing 50% by weight are not compatibilized.

Claims (2)

[Claims] 1. A total amount of 60 to 90% by weight of (A) nylon 46 resin and (B) polybutylene terephthalate resin,
(C) A resin composition comprising 10 to 40% by weight of glass fiber, and the weight ratio of the component (B) in the total amount of the components (A) and (B) is in the range of 0.10 to 0.40. 2. An electronic component comprising the resin composition according to claim 1.