JPS5898361A - Electrically insulating, thermosetting resin composition - Google Patents

Abstract

PURPOSE:To provide the titled compsn. having excellent thermal shock strength and workability, consisting of a liquid polyol, a polyisocyanate and a specified powdered crystalline alumino-silicate salt. CONSTITUTION:2-50pts.wt. powdered crystalline aluminosilicate salt of the formula MeO.Al2O3.mSiO2.nH2O (wherein Me is two atoms of an alkali metal or one atom of an alkaline earth metal; m, n are each a numerical value) and having a particle size of 500mu or below and pores having an average diameter of 15Angstrom or below after releasing water of crystallization, and not more than 70vol% inorg. powder such as TiO2, are blended with 100pts.wt. compsn. obtd. by blending a liquid polyol having an MW of 1,500 or below, such as a triol obtd. by adding propylene oxide to glycerol as an initiator, and a polyisocyanate having an MW of 200-1,000 in such a proportion as to give a ratio of the hydroxyl group to the isocyanate group of 0.7-1.0.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermosetting resin composition used as an insulating member of electrical equipment, and is an electrical insulator that has extremely excellent mechanical stability against thermal cycles, that is, thermal shock strength, and excellent workability. The object of the present invention is to provide a thermosetting resin composition for use.

It has long been recognized that casting or impregnating electrical devices with thermosetting resins provides superior insulating or mechanical properties.

This is particularly well known in electrical devices such as semiconductor devices, transformers, and electrically insulating coils.

By the way, epoxy resins, unsaturated polyester resins, silicone resins, phenolic resins, etc. are widely used as thermosetting resins, but the final cured resin' has a resistance to various mechanical stresses of λ1, and is a cured resin. It must not exert mechanical stress on element members such as conductive metal materials, semiconductors, ceramics, etc. that come into contact with the device. What is particularly important is that no abnormalities occur during high and low temperature cooling/heating cycles. Conventional general thermosetting resins Vt may peel off from element materials or crack under thermal cycles, and in extreme cases may even destroy electrical devices. Although these drawbacks can be improved to some extent and eliminated by incorporating nidistomer materials, these nidistomer materials generally do not exhibit good electrical properties, have low thermal strength, have poor thermal stability, and are difficult to expand. The disadvantage is that the coefficients are significantly large. Therefore, among the conventional resin materials, there is no one that is fully satisfactory in all aspects such as electrical, mechanical properties, and thermal properties.

The present invention was made with the aim of significantly improving these drawbacks, and its gist is as follows:
In the thermosetting resin composition for electrical insulation, the composition is
(1) Liquid polyol with a molecular weight of 1500 or less, (n
) polyisocyanate with a molecular weight of 200 to 1000, (2
) Powdered crystalline aluminosilicate with a particle size of 500μ or less, which has pores with an average diameter of 15A0 or less after the water of crystallization is desorbed;
Furthermore, if necessary, it is made of inorganic powder, and the blending ratio of each component is (r) + ([1) = 2 to 50 parts by weight per 100 parts by weight, and (5) is A thermosetting resin composition for electrical insulation is characterized in that the proportion of the entire curable resin composition is 70% by volume or less.

However, the features of the present invention are (1) molecular weight 1
When a polyol having a molecular weight of 500 or less, preferably 400 to 1000, is reacted with (n) polyin7anate having a molecular weight of 200 to 1000 to produce a semi-hard or hard cured resin, a powdered crystalline aluminosilicate is used as an essential component. It is a thermosetting resin composition in which inorganic powders such as silica and alumina are further blended as necessary. Urethane elastomers are highly elastic rubber products obtained by reacting polyols, diamines, and polyisocyanates, and are available in cast, cross-wire, and thermoplastic types, and are used in sheets, films, adhesives, rolls, solid tires, couplings, and waterproofing. Although it is widely used in vibration materials, bunonyu, shoe soles, artificial leather, etc., it generally has poor electrical properties and is not sufficient as an insulating member for electrical devices. The present invention was completed after discovering that a semi-rigid or hard urethane resin provides relatively good electrical properties and has excellent mechanical stability against cooling and heating cycles, and conducted various research into its application to electrical devices. .

The thermosetting resin composition of the present invention preferably has a molecular weight of 11 isoo or less, preferably 400 to 1000, as component (1).
liquid polyol is used. Molecular weight 400. Propylene oxide added using glycerin as an initiator.
700.1000.1500 triol, diglycerin with propylene oxide added, molecular weight 500~
Thermosetting resins used in the present invention include tetraol with a molecular weight of 600 to 700, hexaol with a molecular weight of 600 to 700, which is obtained by adding propylene oxide to sorbitol, and diol with a molecular weight of 400 to 700, which is obtained by adding propylene oxide to propylene glycol. Suitable as the polyol component of the composition. In addition, natural castor oil containing ricinoleic acid ester of glycerin as a main component, 7-nolic acid, propylene glycol, and trimethylol propane ester can also be used. Liquid polyols with a molecular weight of 1500 or less, which are obtained by co-adding propylene oxide and ethylene oxide to propylene glycol or glycerin, can also be used. Furthermore, polyether diol in which propylene oxide is added to bisphenol A can also be used. The purpose of the present invention is to provide a thermosetting resin composition for electrical insulation with excellent workability, and from the viewpoint of workability, it is desirable that the polyol be liquid at room temperature. If a polyol with a molecular weight of 1,500 or more is used, the cured resin will soften and become an elastomer, resulting in a significant drop in electrical and mechanical properties, so it is not desirable to use a polyol with a molecular weight of 1,500 or more in the present invention, but it may be used in combination in a small amount. It does not prevent this. For example, molecular weight 400
The above triol is used in combination with hydroxyl-terminated liquid polyptadiene, which is a polyol that provides a cured product with exceptionally good electrical properties even though the molecular weight is large.

Suitable polyisocyanates as component (II) of the composition of the present invention have molecular weights in the range of 200 to 1000, including diphenylmethane diisocyanate (MDI,
molecular weight 250), partially carbodiimidized and liquefied diphenylmethane diisocyanate, crude MD
A purified pretreated condensate polyinocyanate of MDI, designated I, is suitable.

A trimeric polyisocyanate (molecular weight 504) of hexamethylene diisocyanate can also be used.

In addition, polyisocyanates having an average molecular weight of 1000 or less, which are modified by partially reacting the above polyisocyanates with polyols, are also suitable.

Polyiso7anate partially reacted with a polyol has improved compatibility with the polyol of component (1), giving the advantage that the reaction during curing proceeds slowly, but the average molecular weight is 10r! Polyisocyanates modified to 0 or more have high viscosity and poor workability, and are not suitable for the present invention because they tend to gel during storage due to the influence of humidity and temperature. Molecule [polyisocyanate below 200 is
As represented by tolylene diisocyanate (molecular weight 174), it generally has a high vapor pressure even at room temperature, and may cause health problems if it is not handled with strict safety precautions such as ventilation in the work area and wearing a gas mask. It has high properties and is therefore unsuitable for use in the present invention.

The essential component (2) of the composition of the present invention is a powdery crystalline aluminosilicate having a particle size of 500μ or less and having pores with an average diameter of 15A' or less after the removal of crystal water, and having the general formula % Me is 2 atoms of alkali metal or 1 atom of alkaline earth metal
It represents an atom, and m%n is a numerical value. Those in which Me is a sodium atom are called zeolites, and various natural and synthetic products are commercially available. A crystalline aluminosilicate suitable for the present invention is one obtained by partially or fully removing crystallization water from the crystalline hydrated aluminosilicate of the above formula by heating. The crystalline aluminosilicate from which the water of crystallization has been removed has uniform pores with a diameter af, and selectively and strongly adsorbs low-molecular polar substances, and when the 1fc of the present invention is used, it strongly adsorbs trace amounts of water in the composition.

It prevents foaming during curing due to water absorption, making it possible to manufacture electrical devices with excellent electrical and mechanical properties.

If a material having pores with an average diameter of 15β or more is used, the polyol of component (1) will also be adsorbed into the pores, resulting in insufficient adsorption of trace amounts of water and the desired purpose will not be achieved. The present invention cannot be applied to the pore size of . The composition of the present invention is applied to electrical devices by processes such as casting, impregnation, painting, and putty filling, and in order to provide uniform and sufficient characteristics, the above aluminosilicate is powdered and granular. A diameter of 500μ or less is suitable. In the present invention, it is desirable to use an ordinary inorganic powder together with the crystalline aluminosilicate. Examples of inorganic powders include alumina,
Powders include silica, zirconium silicate, hydrated alumina, calcium carbonate, titanium dioxide, tribasic lead sulfate, and lead oxide. Further, if necessary, short glass fibers, asbestos powder, mica powder, chicken tropic agents such as Erosil, etc. can be added. In general, the amount of inorganic powder blended is as large as possible within the range that satisfies the manufacturing workability of electrical devices, and the amount of blended is determined by the particle size of the inorganic powder,
Although it varies depending on the shape etc., up to about 70 volumes can be added to the entire composition. Note that depending on the type of electrical device, it is also possible to use a composition that does not contain any ordinary inorganic powder. The ratio of component (1) to component (II) in the composition used in the present invention is appropriately such that the ratio of hydroxyl groups to incyanate groups is in the range of 0.7 to 1.0. The minimum amount of component (g) that can effectively adsorb moisture in the entire composition is required. Although it is related to the degree of desorption of crystal water before use, (1) + (II) = 2 for 100 parts by weight.
Approximately parts by weight are necessary. Further, the amount of crystalline aluminosilicate as the component (or so) may be within a range that satisfies the purpose of use in the present invention, and does not need to be in an amount of 50 parts by weight or more.

The thermosetting resin composition of the present invention may optionally contain a flame retardant,
Coloring agents, anti-deterioration agents, reaction accelerators, etc. can also be blended.

When applying the composition of the present invention, the surface of the element material constituting the electrical device can be treated in advance with a known coupling agent, or the affinity with the resin can be further improved by adding a small amount to the composition. I can do it.

Next, the present invention will be explained with reference to the drawings. 1 to 5 show various examples of application of the present invention. FIG. 1 is a cross-sectional view of an impedance element molded with resin, where 1 is a case, 2 is an impedance element housed in the case, and a primary coil 4 and a secondary coil 5 are wound around a magnetic core 3. 6 is a thermosetting resin composition of the present invention.

FIG. 2 is a cross section of a resin support insulator, where 7 is the thermosetting resin composition of the present invention and 8 is a metal fitting embedded in the resin. FIG. 3 shows the cross section of the cable head, 9 is the cable head tube, 10 is the thermosetting resin composition of the present invention, 1
1 is a cable. FIG. 4 is a cross section of a linear connection part of the cable, where 12 is a connection box, 16 is an injection port, 14 is a cable core, and 15 is a thermosetting resin composition of the present invention.

FIG. 5 is a cross-sectional view of a copper busbar covered with a glass cloth sleeve and then molded to be impregnated with resin, in which 16 is the copper busbar and 17 is the thermosetting resin composition of the present invention.

As described above, the composition of the present invention has an electric potential of y, :u=,
,.

The present invention can be applied to molding, impregnation molding, botting, coating, and other processes for constituent element materials, and can provide an electrical device with high reliability in terms of various properties. The scope of application of the composition of the present invention is wide-ranging, including rotating electric machines, transformers, current transformers, circuit breakers, heating appliances, lighting appliances, electrical equipment, electric wires and cables, and electronic circuits.

Next, the composition of the present invention will be explained in more detail by showing Examples and Comparative Examples.

Example 1 (a) Trio-rue with a molecular weight of 700 to which propylene oxide was added using glycerin as an initiator --- 63 parts by weight (b) Crude MDI --- 37 overlapping parts (C) Powdered crystallinity Aluminosilicate (synthetic zeolite type, pore size 4A)
', particle size 5μ or less 98%)------10 parts by weight - (d) Silica powder------50 volume Chi (b) above
The three components (a) to (d) excluding (a) to (d) are uniformly mixed to form a main ingredient, and the mixture is stored in a sealed container. Immediately before use, add (b) as a curing agent to the main ingredient and mix uniformly. This composition was used to mold an impedance device for automobile electrical equipment shown in FIG. This impedance device was subjected to an energization test cycle in which the coil temperature reached a maximum of 150C. A cycle of 10 minutes of current application and 10 minutes of cooling time was repeated 500 times, but no abnormalities such as cracks in the mold resin occurred.

Next, a heat cycle of 12 hours at 130C and 12 hours at 90C was repeated 30 times in a heat cycle constant temperature oven, but no abnormality occurred.

Comparative Example 1゜(a) Bisphenol A epoxy (epoxy equivalent: 18
5) ----100 parts by weight (b) Methyltetrahydrophthalic anhydride---80 parts by weight (c) Tinnous octylate---1 part by weight ((1) Silica powder---- ---4rl capacity chi (a) to (d) above
An epoxy resin composition was prepared by uniformly mixing the following components, and an impedance device for an electrical component shown in FIG. 1 was cast and heat-cured. When this epoxy molded product was subjected to a heat cycle test at 90C for 2 hours using a heat cycle constant temperature bath, cracks occurred in the resin at the low temperature side of the first cycle.

Example 2 (a) Trio-ru--50 with a molecular weight of 400 to which propylene oxide was added using glycerin as an initiator.
Part by weight (b) Crude MDI---50 1 part by weight (C) Powdered crystalline aluminosilicate (synthetic zeolite type, pore size 6A
0, particle size 74μ or less)------7 parts by weight (d) Silica powder------40 volume Ch A composition was prepared from the above four components in the same manner as in Example 1, The support insulator shown in FIG. 2 was manufactured by vacuum casting into a mold.

About this support insulator - 5 DC (in air) 2 hours = 90
C (in air), a 2-hour heat cycle was repeated 30 times, but no abnormality such as cracking occurred. Next 900.
A thermal shock test of 30 minutes in J-ROC water and 60 minutes in dry ice-ethanol was repeated 10 times, but no abnormality occurred.

Comparative Example 2 The same composition as in Example 2 was used except that the component (c) powdered crystalline aluminosilicate of Example 2 was removed.
The support insulator shown in the figure was vacuum cast.

This molded insulator produced a large number of bubbles during curing, and the molded product was not satisfactory in appearance, electrically, and mechanically.

Example 5 (a) Trio-rue with a molecular weight of 70 Cl to which propylene oxide was added using glycerin as an initiator
63 parts by weight (1)) Crude MDI---67 superimposed part (C) Powdered crystalline aluminosilicate (based on synthetic zeolite, pore size 4
7e1 Particle size 5 μ or less 98%) - 10 parts by weight (d) Fused quartz powder 20 parts by volume After uniformly mixing the above four components, defoaming under reduced pressure, and then The cable head shown in FIG. 3 was poured and cured. This is DC75KV
It is a 3-core cable head, with A C2KV/
It passed the withstand voltage test of 1 minute and high voltage part DC 120KV/10 minutes. 1. Submerge this cable head in 5C water for 10 minutes.
A heat shock test of 1° minute in 50C hot water was conducted three times, and the corona characteristics before and after were examined. At the 50PC level, the corona start voltage was 18KV and the extinction voltage was 17KV, and no change occurred in the corona characteristics before and after the heat shock.

Example 4 (a) Trio-ru-6 with a molecular weight of 700 to which propylene oxide was added using glycerin as an initiator
0 parts by weight (b) Hydroxyl group-terminated liquid polybutadiene (molecular weight 2800
)---7 parts by weight (C) Liquefaction modified MDI---33 parts by weight (→Powdered crystalline aluminosilicate (synthetic zeolite type, pore size 4R,
Particle size: 74μ or less) -------10 parts by weight (θ) Fused quartz powder ----40 volume A composition consisting of the above five components was prepared, and the cable shown in Figure 4 was prepared. It was injected into the connection box of the connection part and cured at room temperature. After confirming the initial characteristics through a withstand voltage test and a corona property test, the cable conductor temperature was increased to 90t? The energization heat cycle test (3 hours of energization, 3 hours of energization, cooling time with interruption of current) was repeated 10 times. After the electrical heat cycle, both the withstand voltage and corona properties met the test standards, showing sufficient performance.

Example 5 (a) Trio-ru-2 with a molecular weight of 400 to which propylene oxide was added using glycerin as an initiator
8 parts by weight (b) Trio-ru-2 with a molecular weight of 700 to which propylene oxide was added using glycerin as an initiator.
8 parts by weight (C) Crude MDI---44 parts by weight (d) Powdered crystalline aluminosilicate (synthetic zeolite type, pore size 4
Ao, particle size of 5 μm or less, 98% or more) - 8 parts by weight A composition consisting of the above four components was prepared and impregnated into a copper busbar covered with a glass cloth sleeve as shown in FIG. 5. A heat cycle of 9 DC in air for 2 hours and 0 C in air for 12 hours was repeated 10 times for this copper bus bar, but no abnormalities such as cracks occurred in the impregnated mold resin.

[Brief explanation of drawings]

FIGS. 1 to 5 are explanatory drawings showing five examples of application of electrical devices to which the composition of the present invention is applied. 1... Case, 2... Impedance element, 6...
・Thermosetting resin composition 71f1? 2 Country 1- Mukov''I' T 4 Mouth

Claims (1)

[Claims] 1. A thermosetting resin composition used as an insulating member of electrical devices, the composition of which is (1) molecules l1150
0 or less liquid polyol, (II) molecular weight 200~
Polyisocyanate of 1000, (up to) Particle size 500 with pores of average diameter 15X or less after the water of crystallization is desorbed
It is composed of powdered crystalline aluminosilicate with a size of less than μ, and the blending ratio of each component is such that (+10 is 2 to 50 parts by weight relative to (1) +(It) -10 parts by weight) A thermosetting resin composition for electrical insulation, characterized by: 2. A thermosetting resin composition used as an insulating member of an electrical device, the composition of which is (I) a molecular weight of 1500;
The following liquid polyol, (It) molecular weight 200-1
000 polyisocyanate, (■0 particle size 500 having pores with an average diameter of 15A' or less after desorption of water of crystallization)
Consists of a powdered crystalline aluminosilicate with a particle size of less than μ and (5) an inorganic powder, and the blending ratio of each component is as described above in (1) +
(II) The ratio of (2) to -100 parts by weight is 2 to 50 parts by weight, and the ratio of 0) to the entire thermosetting resin composition is 70 to -i: q or less. 1. A thermosetting resin composition for electrical insulation.