JP2009067816A - Polyurethane resin electric insulation composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyurethane resin electric insulation composition which does not undergo deterioration in insulation properties even in a wet hot environment and has a high radiation effect and high flame retardancy. <P>SOLUTION: The polyurethane resin electric insulation composition contains (a) a polybutadiene having two or more hydroxy groups, (b) a polyisocyanate, (c) a plasticizer, (d) a zeolite and (e) a hydrated metal compound. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polyurethane resin electrical insulation composition that can be suitably used for insulation treatment of electrical / electronic components, and to electrical / electronic components insulated using the composition.

  Conventionally, an electrically insulating polyurethane resin has been widely used as an insulating sealing agent for protecting various electric and electronic components on an integrated circuit and a circuit board from moisture and dust in the air. (For example, Patent Document 1 and Patent Document 2).

  When electronic components are mounted on the circuit board described above, lead-containing solder has been conventionally used. However, in recent years, solder containing no lead (lead-free solder) has been popularized due to environmental problems. However, lead-free solder improves mechanical properties such as strength at the joint, reduces cracks that occur in the joint during soldering, and cracks that occur when the circuit board is subjected to a thermal shock test. For the purpose of reduction, rosin, a solvent, and a surfactant, a thixotropic agent, etc. are blended as a flux (flux) as necessary. In a board in which electronic parts and the like are soldered using such lead-free solder, there is a problem that the surface active component in the flux corrodes the wiring of the board and copper as a solder component in the presence of moisture in the atmosphere. . There is also a problem that the surface active components and the electrolyte in the flux residue are eluted in the adsorbed moisture, and these components reduce the insulation between the electrodes and wirings on the substrate. Furthermore, in recent fine pitch mounting, since the conductor spacing is small, the electric field voltage under the same operating voltage is high, and the electrochemical migration of the above components is likely to occur.

For this reason, even if it uses an electrically insulating polyurethane resin, there exists a problem that insulation will fall in a wet heat environment. In recent years, as seen in LSI and the like, electronic circuits have been integrated and highly functionalized, and heat generation has become localized as the amount of heat radiation increases. Therefore, how to dissipate the heat generated in the electronic circuit board has become an important issue.
JP 2006-316216 A Japanese Patent Laid-Open No. 9-324027

  In view of the above problems, the present invention, when used as a sealing agent for circuit boards using lead-free solder, insulating materials such as electrical and electronic parts, the insulation characteristics do not deteriorate even in a humid heat environment, And it aims at providing the polyurethane resin electrical insulation composition with a high heat dissipation effect and a flame retardance. Another object of the present invention is to provide an electrical / electronic component that is insulated using the polyurethane resin electrical insulation composition.

  The polyurethane resin electrical insulating composition of the present invention comprises (a) a polybutadiene having two or more hydroxyl groups, (b) a polyisocyanate, (c) a plasticizer, (d) a zeolite, and (e) a hydrated metal compound. And (e) 100 parts by weight of the hydrated metal compound mixed in a weight ratio of the hydrated metal compound / water = 8/80 and left at 80 ° C. for 13 hours. 10 to 100 parts by weight of the supernatant having an electrical conductivity of 40 μS / cm or less is obtained.

  In the above, it is preferable that 0.01 to 5 parts by weight of the (d) zeolite is contained in 100 parts by weight of the total amount of the polyurethane resin electrical insulating composition.

  In the above, it is preferable that 50 to 80 parts by weight of the (e) hydrated metal compound is contained in 100 parts by weight of the total amount of the polyurethane resin electrical insulating composition.

  In addition, the (e) hydrated metal compound is preferably a mixture of an average particle size of 1 to 10 μm and an average particle size of 15 to 50 μm.

  The (e) hydrated metal compound is preferably aluminum hydroxide.

  The electrical / electronic component of the present invention is characterized by being subjected to an insulation treatment using the polyurethane resin electrical insulation composition described above.

  Since the polyurethane resin electrical insulation composition of the present invention contains (d) zeolite and (e) a hydrated metal compound, the polyurethane resin inherently has excellent electrical insulation even in a humid heat environment. High heat dissipation effect can be maintained. As a result, highly reliable electric / electronic components can be provided.

  Therefore, it is used to protect coils and electronic / electric parts used in electric washing machines, toilet seats, water heaters, water purifiers, baths, dishwashers, electric tools, automobiles, motorcycles, etc. from moisture and moisture. It can be suitably used as a sealing agent, a sealing agent, a coating agent, and an insulating material for capacitors and converters.

  Embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments.

  In the present invention, (a) polybutadiene having two or more hydroxyl groups is used as the polyol component. When such polybutadiene is used, the obtained polyurethane becomes a good elastomer (rubber elastic body), and can be brought into close contact with a circuit board and electric / electronic parts to exhibit good insulation. (A) The molecular weight (number average) of polybutadiene having two or more hydroxyl groups is preferably in the range of 700 to 8,000, more preferably in the range of 1,000 to 4,000, and in the range of 1500 to 3000. Further preferred. Examples of the polybutadiene having two or more hydroxyl groups suitable for the molecular weight include 1,4-polybutadiene having a terminal hydroxyl group. Examples of commercially available products include trade names “poly bd R · 45HT, poly bd R · 45M, poly bd R · 15HT ”(manufactured by Idemitsu Petrochemical Co., Ltd.).

  As the (b) polyisocyanate in the present invention, conventionally known ones can be used, and examples thereof include aromatic polyisocyanates, aliphatic polyisocyanates, and alicyclic polyisocyanates. Examples of the aromatic polyisocyanate include diphenylmethane diisocyanate (MDI), polymethylene polyphenylene polyisocyanate (crude MDI), tolylene diisocyanate (TDI), polytolylene polyisocyanate (crude TDI), xylene diisocyanate (XDI), and naphthalene diisocyanate. (NDI). Examples of the aliphatic polyisocyanate include hexamethylene diisocyanate (HDI). Examples of the alicyclic polyisocyanate include isophorone diisocyanate (IPDI). In addition, polyisocyanate obtained by modifying the above polyisocyanate with carbodiimide (carbodiimide-modified polyisocyanate), isocyanurate-modified polyisocyanate, urethane prepolymer (for example, a reaction product of polyol and excess polyisocyanate, and isocyanate group The one having a terminal) can also be used. These may be used alone or as a mixture. Among these, diphenylmethane diisocyanate, polymethylene polyphenylene polyisocyanate, and carbodiimide-modified polyisocyanate are preferable. This is because they are inexpensive, liquid and easy to handle, low volatility and high safety.

  The blending amount of (b) polyisocyanate is 0.6 to 2.0 times equivalent, preferably the isocyanate group in (b) polyisocyanate is (b) the total amount of hydroxyl groups contained in the raw material other than polyisocyanate. Is preferably a ratio of 0.7 to 1.5 times equivalent. If it is less than 0.6 times equivalent, physical properties such as incomplete curing, resin strength, and durability are likely to deteriorate, and if it exceeds 2.0 times equivalent, a hard and brittle resin tends to be formed.

  The plasticizer (c) used in the present invention is preferably a plasticizer having no hydroxyl group from the viewpoint of imparting elasticity to the cured product and reducing the viscosity during preparation of the composition. Such plasticizers include phthalates such as dioctyl phthalate, diisononyl phthalate, diundecyl phthalate, trimellitate plasticizers such as triethylhexyl trimellitate, triisodecyl trimellitate, tricresyl phosphate, trisoxy Examples thereof include phosphate esters such as rhenyl phosphate, cresyl diphenyl phosphate, xylenyl phosphate, triphenyl phosphate.

  (C) The blending ratio of the plasticizer is 50 to 500 weights with respect to 100 parts by weight of the total amount of (a) polybutadiene having a hydroxyl group, (b) polyisocyanate, and polyol components other than polybutadiene having a hydroxyl group described later. Parts, preferably 100 to 300 parts by weight. If the plasticizer is less than the above range, the viscosity becomes high and the workability is lowered, and if it exceeds the above range, the mechanical properties of the cured product are lowered and the moisture resistance of the resin composition tends to be lowered.

  The zeolite (d) used in the present invention is added in order to maintain the insulating properties of polyurethane in a moist heat environment. (D) Examples of zeolite include sodium type, calcium type, magnesium type, potassium type and ammonium type zeolite, and commercially available products include mixtures thereof. For example, trade names such as Zeolum A-3 and Zeolum A-4 ( Tosoh Corporation).

  (D) The blending ratio of zeolite in the polyurethane resin electrical insulating composition in a total amount of 100 parts by weight is preferably 0.01 to 5 parts by weight, and more preferably 0.1 to 5 parts by weight. If the blending ratio is less than the above range, the effect of maintaining the insulation characteristics in a moist heat environment cannot be obtained.

  The (e) hydrated metal compound used in the present invention is added for imparting thermal conductivity in addition to flame retardancy, and examples thereof include aluminum hydroxide and magnesium hydroxide, and water Aluminum oxide is more preferred.

(E) The blending ratio of the hydrated metal compound in the total amount of 100 parts by weight of the polyurethane resin electrical insulating composition is preferably 50 to 80 parts by weight. If the blending ratio is less than the above range, the flame retardancy and thermal conductivity tend to decrease, and if it exceeds the above range, the viscosity becomes high and the workability tends to decrease.

  The (e) hydrated metal compound is preferably a mixture of one having an average particle diameter of 1 to 10 μm and 15 to 50 μm. When a compound having an average particle size of less than 1 μm is added, the viscosity tends to increase and the workability tends to be lowered. When a compound having an average particle size of more than 50 μm is added, it tends to settle during storage and the resulting polyurethane resin is brittle. Tend to be. By using two kinds of hydrated metal compounds having different average particle diameters in this way, a hard cake of the hydrated metal compound precipitated during storage can be prevented and redispersion can be facilitated.

  Further, (e) the hydrated metal compound is mixed at a weight ratio of hydrated metal compound / water = 8/80, and after standing at 80 ° C. for 13 hours, the electrical conductivity of the supernatant is 40 μS / cm or less. It is preferable to use 5 to 100 parts by weight of the product based on 100 parts by weight of the total amount of the hydrated metal compound. When the electrical conductivity is 40 μS / cm or less, the deterioration of the insulation characteristics in a humid heat environment is further reduced.

  Moreover, polyol compounds other than polybutadiene having a hydroxyl group can be added to the polyurethane resin composition to the extent that the effects of the present invention are not impaired. Examples of these polyol compounds include polyester polyols composed of ricinoleic acid and polyhydric alcohols, and commercially available products include castor oil (containing 87.0 to 91.0% ricinoleic acid as a fatty acid).

  Furthermore, an ultraviolet absorber, a catalyst, an antifoaming agent, an antioxidant, a pigment (colorant) and the like can be blended with the polyurethane resin composition according to the present invention as necessary.

  Next, the present invention will be described in more detail by way of examples, but the present invention is not limited thereby.

  A polyurethane resin electrical insulating composition was prepared as shown below with the blending composition and blending amount (parts by weight) shown in Table 1.

Here, the detail of the component shown in Table 1 is shown below.
(A) Polybutadiene having two or more hydroxyl groups Idemitsu Petrochemical Co., Ltd., trade name: poly bd R · 45HT
(B) Polyisocyanate: Carbodiimide-modified diphenylmethane diisocyanate-containing liquid MDI
(Nippon Polyurethane Co., Ltd., trade name: Millionate MTL)
(C) Plasticizer diisononyl phthalate (manufactured by Shin Nippon Rika Co., Ltd., trade name: SUNSOIZER DINP)
Trixylenyl phosphate (manufactured by Daihachi Chemical Co., Ltd., trade name: TXP)
(D) Zeolite manufactured by Tosoh Corporation, trade name: Zeolum A-4
Product name: Zeorum A-3, manufactured by Tosoh Corporation
(E) Hydrated metal oxide: Aluminum hydroxide, manufactured by Showa Denko KK, trade name: Hygielite H.31
(Average particle size 20 μm, electrical conductivity 61 μS / cm)
Showa Denko K.K., trade name: Heidilite H.32
(Average particle size 8μm, electric conductivity 65μS / cm)
Showa Denko K.K., trade name: Heidilite H.32.I
(Average particle size 8μm, electrical conductivity 19μS / cm)
Product name: B153E, manufactured by Nippon Light Metal Co., Ltd.
(Average particle size 15 μm, electrical conductivity 25 μS / cm)
(Other raw materials)
Castor oil, manufactured by Ito Oil Co., Ltd., trade name: Castor oil Martok A
(Hydroxyl value: 160 mgKOH / g, average molecular weight 947)
In the above (e) hydrated metal oxide, the electric conductivity is the electric conductivity of the supernatant after mixing at a weight ratio of aluminum hydroxide / water = 8/80 and leaving at 80 ° C. for 13 hours. Say.

<Preparation of polyurethane resin electrical insulation composition>
(B) A mixture of raw materials excluding polyisocyanate was mixed for 30 minutes using a disper (manufactured by Primics Co., Ltd., model name: TK homodisper 2.5 type). Next, polyisocyanate was added so that NCO / OH = 1.05, and mixing and defoaming were performed.

<Preparation of test specimens and test samples for electronic parts>
The polyurethane resin electrical insulating composition obtained above was poured into a metal mold and cured at 60 ° C. for 48 hours to obtain a urethane resin test piece.

  Moreover, the liquid mixture created on the same conditions is inject | poured into the aluminum case (depth 10mm) which installed the board | substrate in which the comb-shaped pattern using lead-free solder (Senju Metal Industries Co., Ltd. product: SPARKLE ESC21) was installed, and 60 A test sample for an electronic component cured at 48 ° C. for 48 hours and insulated.

  Various physical properties of the test piece obtained by the above method were measured by placing the initial test piece and the test piece in a furnace at 70 ° C. and a relative humidity of 90% for 1000 hours, and then leaving it in a thermostatic chamber at 25 ° C. for 1 hour. A test piece (hereinafter referred to as a test piece after wet heat treatment) was used.

  The insulation resistance of the test sample for electronic parts subjected to insulation was measured with the initial test sample for electronic parts obtained by the above method at a temperature of 70 ° C. and a relative humidity of 90% with a direct current of 27 V applied to the electronic board. The test was performed using an electronic component test sample (hereinafter referred to as an electronic component test sump after wet heat treatment) that was left in a thermostatic chamber at 25 ° C. for 24 hours after being put in a furnace for 1000 hours.

<Evaluation test>
The following evaluation tests were performed using the test pieces and the test samples for electronic parts, and the results are shown in Table 1.

(1) Stability and redispersibility of dispersion liquid A mixture of raw material components excluding polyisocyanate was mixed for 30 minutes using a disper, then poured into a glass bottle of φ58 mm × 181 mm up to the 8th minute and allowed to stand at 25 ° C. .

  One week later, a sample in which the precipitation of the hydrated metal compound was less than 10 mm from the bottom of the glass bottle was determined as “stability ○”.

  Further, one month later, a precipitated hydrated metal compound that can be easily redispersed with a metal spatula was determined as “redispersibility ○”.

(2) Hardness of urethane resin Using a test piece (50 mm × 50 mm, thickness: 6 mm), the hardness was measured according to JIS K 6253 using an Asker A type hardness meter, Kobunshi Keiki Co., Ltd.

  An initial specimen having a hardness of 90 or less and a specimen having a hardness of 20 or more after the wet heat treatment was judged as “◯”.

(3) Insulation resistance of urethane resin Using SE-10E manufactured by Toa Denpa Kogyo Co., Ltd., applying a measurement voltage of 500 V to the test piece (50 mm × 50 mm, thickness: 3 mm) at 25 ± 5 ° C. and 65 ± 5% RH Then, the value after 60 seconds was measured.

An initial test piece having a resistance value of 10 ¹⁰ Ω · m or more and a test piece having a resistance value after wet heat treatment of 10 ⁸ Ω · m or more was judged as “◯”.

(4) Flame retardance of urethane resin The test piece was measured according to UL94 standard (plastic material flammability test). The thickness of the test piece was 3.0 mm.

  Also, in the UL94 standard, the determination is made with two ignitions, but the ignition is performed once again (total three ignitions), the combustion after ignition and the glowing time are within 30 seconds, there is no combustion to the clamp part, and the fireball The case where there was no cotton ignition by dripping was determined as “third ignition ○”.

(5) Thermal conductivity of urethane resin The thermal conductivity was measured using a test piece in accordance with JIS R 2618 using a thermal conductivity meter (GTM-D3, manufactured by Kyoto Electronics Industry Co., Ltd.).

  A sample having a thermal conductivity of 0.5 W / m · K or more was judged as “◯”.

(6) Insulation resistance value of test sample for electronic parts According to JIS Z 3197, a numerical value after 60 seconds of DC 100V application of a test sample for electronic parts using a super insulation resistance meter (manufactured by Kawaguchi Electric Manufacturing Co., Ltd., VE-30) Was measured.

A sample having a resistance value of 10 ² MΩ or more in the initial electronic component test sample and the electronic component test sample after the wet heat treatment was determined as “◯”.

<Evaluation test results>
As is clear from Table 1, the polyurethane resin electrical insulation composition of each example is excellent in dispersion stability, and hardness, insulation resistance value, flame retardancy, heat conduction even when the cured urethane resin is subjected to wet heat treatment. It can be seen that the rate does not decrease. On the other hand, the polyurethane resin electrical insulation composition of each comparative example did not satisfy the criteria for any of the above evaluation items.

  The polyurethane resin electrical insulation composition of the present invention and electrical / electronic parts using the same have high flame retardancy, and can maintain thermal conductivity, insulation resistance value, etc. even after wet heat treatment. -It can be used in the field of electronic equipment.

Claims (6)

(A) a polybutadiene having two or more hydroxyl groups;
(B) a polyisocyanate;
(C) a plasticizer;
(D) zeolite,
(E) a polyurethane resin electrical insulating composition comprising a hydrated metal compound,
In (e) 100 parts by weight of the hydrated metal compound, the hydrated metal compound / water is mixed at a weight ratio of 8/80 and left at 80 ° C. for 13 hours. The supernatant has an electrical conductivity of 40 μS / cm. A polyurethane resin electrical insulation composition comprising 10 to 100 parts by weight of the following.   2. The polyurethane resin electrical insulation composition according to claim 1, wherein the polyurethane resin electrical insulation composition contains 0.01 to 5 parts by weight of the zeolite (d) in a total amount of 100 parts by weight of the polyurethane resin electrical insulation composition.   3. The polyurethane resin electrical insulation according to claim 1, wherein 50 to 80 parts by weight of the (e) hydrated metal compound is contained in 100 parts by weight of the total amount of the polyurethane resin electrical insulation composition. Composition.   The polyurethane resin electrical insulation according to any one of claims 1 to 3, wherein the (e) hydrated metal compound is a mixture of one having an average particle size of 1 to 10 µm and one having an average particle size of 15 to 50 µm. Composition.   The polyurethane resin electrical insulating composition according to claim 1, wherein the (e) hydrated metal compound is aluminum hydroxide.   An electrical / electronic component that is insulated using the polyurethane resin electrical insulation composition according to claim 1.