JPS5850007B2 - Flyback transformer insulation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a flyback transformer.

Silicone rubber is used as a casting material for insulating flyback transformers in televisions because it has excellent heat resistance, electrical insulation, and flame retardancy.

The silicone rubber used for the above applications is of the type that crosslinks through a hydrosilation reaction, and is generally selected from organopolysiloxanes having lower alkenyl groups, silica fillers, colorants such as red iron oxide, and platinum and platinum compound catalysts. The composition consists of part A (base material) containing a catalyst, and part B (curing agent) consisting of an organopolysiloxane having a lower alkenyl group, a silica filler, a coloring material, and an organopolysiloxane having a hydrogen atom.

In manufacturing a flybank transformer, these A and B agents are mixed and stirred, and then cast and heated to harden.

However, in order to improve the efficiency of the casting operation, conventional silicone rubber compositions cannot be easily dispersed in a short period of time by stirring and mixing the above-mentioned A and B components at a relatively low speed. Even if the mixture is stirred for a long time in order to obtain good dispersibility, the viscosity increases as shown in the trend diagram shown by curve 1 in Figure 1, and the casting operation cannot be carried out smoothly.
Voids may occur in the flyback transformer,
Silicone rubber has the disadvantage of overflowing.

Such a phenomenon cannot be inferred from conventional knowledge, and the reality is that there is no method to prevent it.

Therefore, manufacturers of flyback transformers have no choice but to adopt inefficient methods such as slowing the casting speed as much as possible or gradually casting in 2 or 3 steps. Ta.

Incidentally, the increase in viscosity due to high-speed stirring and mixing and the fluidity basidia phenomenon occur due to the interaction between the silica powder blended as a filler and the organopolysiloxane.

Therefore, Special Public Interest Publication No. 52-36531. US Patent No. 29380
Although the above problems have been solved to some extent by using silica powder with a pre-surface treatment as seen in No. 09 and U.S. Pat. Since powder must be used, the silicone rubber composition has the disadvantage of being expensive.

The purpose of the present invention is that even when stirring and mixing at high speed for a long time,
It is an object of the present invention to provide a method for efficiently manufacturing a flyback transformer using silicone rubber for casting, which exhibits a small increase in viscosity and no decrease in fluidity.

The silicone rubber composition for flyback transformer insulation used in the present invention contains the following (a) to (feathers) as essential components.

((1) Diorganopolysiloxane represented by the general formula (R in the formula is a substituted or unsubstituted monovalent hydrocarbon group having no aliphatic unsaturated bond, n is a positive integer), 100 parts by weight (0) (CH2=CH)R2SiOo, 5 units and R
Organopolysiloxane copolymer consisting of 35100.5 units and SiO2 units (R in the formula represents a substituted or unsubstituted monovalent hydrocarbon group having no aliphatic unsaturated bond) 0.2 to 30 parts by weight (・) A sufficient amount of hydrogen in one molecule to provide 0.7 to 5.0 hydrogen atoms directly bonded to silicon atoms per vinyl group in components (a) and (b) above. 50 to 300 parts by weight of silica filler to organohydrodiene polysiloxane having 3 or more atoms) Catalytic amount of platinum or platinum compound Particularly (b) is a key component of the present invention and should be blended with it. Therefore, even when stirred or mixed for a long time, the fluidity does not decrease as shown in the trend chart shown by straight line 2 in FIG. 1, and a flyback transformer with excellent insulation can be efficiently produced.

Each component used in the present composition will be explained in detail below.

The diorganopolysiloxane as component (a) used in the present invention is represented by the general formula (i) above, where R is a substituted or unsubstituted monovalent compound having no aliphatic unsaturated bond. Represents a hydrocarbon group, including methyl group,
Alkyl groups such as ethyl and propyl groups, phenyl groups,
Aryl groups such as tolyl groups, cycloalkyl groups such as cyclohexyl groups and cycloheptyl groups, and groups in which the hydrogen atoms bonded to the carbon atoms of these hydrocarbon groups are partially substituted with halogen atoms, cyan groups, etc. Illustrated.

It is preferable that all of the groups represented by R be methyl groups or consist of methyl groups and phenyl groups (70 mol% or more of methyl groups).

In addition, n in the formula represents a positive integer, which means that the diorganopolysiloxane has a viscosity of 50 centistokes or more (n=50), particularly 100 to 500,000 centistokes (n=2000) at 25°C. It is preferable that the value is as follows.

As mentioned above, component (b) is the main component of the present invention,
By adding this ingredient, even by stirring and mixing at high speed,
There is no increase in viscosity or decrease in fluidity, and it maintains excellent fluidity and castability.

The component (b) itself is conventionally known, and for example, when the monovalent hydrocarbon group represented by R is a methyl group, (a) (CH2=CH)R2Si00.
(CH2-CH) (CH3) 2 as a 5 unit source
S iCl , (CH2=CH)(CH3)2-8iO
8i (Cf(3)2(Cf(=CH2), (b)R
(CI(3)3SiC1 as a unit source of 3Si00.5
, (CH3)3SiO8i(CH3)3, (c) S
By appropriately combining sodium silicate, alkyl silicate, polyalkyl silicate, silicon tetrachloride, etc. as a source of iO□ units, and cohydrolyzing and condensing them in the presence of an acid, a copolymer made of these three types of siloxane units can be obtained. Obtained as a polymer.

Copolymerized organopolysiloxanes with various properties can be obtained by changing the ratio of the above components a), (b) and (c), but in the present invention, R3S iOo
, 5 units and (CH2=CH) R2S ioo, the molar ratio of the sum of 5 units and the SiO2 unit is 0.5:1 to 2-0:
1, and the copolymerized organopolysiloxane preferably has a vinyl group content of 0.5 to 3.0% by weight and a hydroxyl group content of 0.1 to 3.0% by weight.

It is well known, as described in Japanese Patent Publication No. 46-11982 and Japanese Patent Publication No. 52-28463, that such components act as wetting agents for fillers when blending each component and have the effect of lowering the viscosity of the blend. However, stirring these at high speed,
Even in the mixing method of the present invention, it was unexpected that the effect of suppressing the phenomenon of viscosity increase and fluidity decrease would be exhibited.

Although the mechanism is not clear, the hydroxyl groups in the copolymerized organopolysiloxane form polar groups (OH groups) on the silica surface.
This is probably due to the action of reacting with the silica powder and preventing secondary agglomeration of the silica powder during high-speed stirring.

However, the blending amount of component (b) is not particularly limited, but is (0.2 to 3 parts by weight per 100 parts by weight of component (1)).
It is desirable that the amount is 0 parts by weight.

If it is less than 0.2 parts by weight, the desired effect will be small, and if it exceeds 30 parts by weight, the effect will not increase and the cost will increase.

(/→The organohydrodiene polysiloxane as the acid component undergoes an addition reaction with the vinyl groups in the components (a) and (b) described above in the presence of a platinum catalyst to be described later to cure this composition. It is considered to be an essential component for providing a cured silicone product with sufficient strength.

There is no particular restriction on the molecular structure of this product as long as it has a 5i-H bond in one molecule, and conventionally manufactured products such as linear structures, cyclic structures, and branched structures can be used. be done.

In these compounds, the organic group bonded to the silicon atom is generally a methyl group, but it may consist mainly of a methyl group, and may also partially be a phenyl group or an alkyl group other than the methyl group.

The amount of component ()) to be used is determined by the amount per vinyl group in component (a) and component (b), since it is required that it exhibits the effect of curing the composition by the above-mentioned addition reaction as a crosslinking agent. A sufficient amount is required to provide 0.7 to 5, preferably 1 to 2.5, hydrogen atoms directly bonded to the silicon atom.

The silica filler as a (-) component is an essential component for imparting mechanical strength, thermal conductivity, flame retardance, etc. to the cured product, and includes fumed silica, precipitated silica, geriatric earth, and quartz powder. , fused silica powder, etc.

Especially for casting, fine quartz powder and fine fused quartz powder are often used.

Note that the amount of these silica fillers to be blended is preferably 50 to 300 parts by weight per 100 parts by weight of component (a) in view of the above-mentioned various properties.

(Platinum or a platinum compound as a force component is used as a catalyst to proceed with the addition reaction between what) and (b) component and (・) component, and platinum black, chloroplatinic acid, , a complex of chloroplatinic acid and an olefin or aldehyde, or an alcohol modification product of chloroplatinic acid.

The amount of these components to be used may be increased or decreased as appropriate depending on the desired curing speed, but may be approximately 0.1 to 50 ppm in pt relative to the amount of component (4) used.

In addition to the above solid components, fillers other than silica such as alumina, clay, calcium carbonate, zinc oxide, titanium dioxide, iron oxide, glass fiber, glass peas, etc. are added for the purpose of lowering modulus and lowering viscosity. There is no problem in adding a relatively low-molecular-weight silicone oil, and further adding a heat resistance improver, a flame retardant, a reaction control agent, an adhesion imparting agent, etc. as necessary.

In addition, the silicone rubber composition of the present invention is generally a two-component type (former A, agent B) in consideration of storage stability.
It is preferable to mix the above-mentioned components (i) (x) H (=t) in the A agent, and the above-mentioned components (i) (b) (·→(-)) in the B agent.

If necessary, various organosilanes, epoxy group-containing organopolysiloxanes, etc. are blended for the purpose of improving adhesion, but this can also be used independently as a C agent, and it is added immediately before the flybank transformer casting operation. Mix it in Part A and use it.

When used, these A and B agents are mixed and a casting operation is performed.

Here, since the silicone rubber composition obtained in the present invention contains the above-mentioned compound, it has the feature that there is very little decrease in fluidity even when the composition is stirred and mixed at high speed for a long period of time.

Therefore, when insulating a flyback transformer with a complicated shape in a short period of time, silicone rubber flows into every corner and there is no internal void, so a transformer with excellent insulation properties can be efficiently obtained.

Next, the present invention will be explained in detail with reference to Examples.

Note that the present invention is not limited to the shape shown in FIG. 2, and can be applied to diodes, ferrite cores, capacitors,
It can also be applied to flyback transformers with built-in resistors and flyback transformers with interlayer insulation using plastic films.

Further, all viscosities shown in Examples and Comparative Examples are values measured at 25°C.

Example 1 100 parts by weight of dimethylpolysiloxane endblocked with vinyl groups at both ends with a viscosity of 500 centipoise, 120 parts by weight of quartz powder with an average particle size of 3 μm, 5 parts by weight of iron oxide powder, an inpropyl alcohol solution of chloroplatinic acid (2% as Pt) Contains) 0.1
Parts by weight, (CH2-CH)(CH3)2-8iOo, 5
units, (CH3)3S iOo, 5 units, and 5i
Consisting of 02 units, (CH2=CH)(CH3)2S
5 parts by weight of an organopolysiloxane copolymer in which the molar ratio of ioo, 5 units and (CH3)3SiOo, 5 units was 1:1 was kneaded using three rolls to produce a blend (4).

In addition, 100 parts by weight of dimethylpolysiloxane endblocked with vinyl groups at both ends with a viscosity of 500 centipoise, 1 part by weight of quartz powder with an average particle size of 3 μm, 10 parts by weight of methylhydrodiene polylinoxane represented by the molecular formula % formula %, the same as used in the formulation eJA). 5 parts by weight of organopolysiloxane copolymer were mixed with three rolls to form a compound (
B) was produced.

The viscosities of formulations (A) and (B) were 40 poise and 25 poise, respectively.

Further, when blends A and (B) were mixed slowly by hand with a spatula at a blending ratio of 1:1, the viscosity was 32 poise.

Further, the mixture (B) was added at a mixing ratio of 1:1 as shown in Figure 3 (10 in the figure is a motor, 11 is a shaft, 12 is a stirring blade, 13 is
14 is the mixed solution, 14 is the A agent, and 15 is the B agent.

1 using the mixer shown in ) at a stirring speed of 200 rpm.
Although the mixture was mixed for 0 minutes, almost no increase in viscosity was observed as shown by straight line 16 in FIG.

Next, using the above A and B agents, a flyback transformer having the shape shown in FIG. 2 (3 in the figure is a silicone rubber composition, 4 is a case, 5 is a secondary coil, 6 is a primary coil, 7 is a
8 is a secondary bobbin, 8 is a primary bobbin, and 9 is a high voltage lead wire.

) was described.

A 1:1 mixed solution of Part A and Part B was mixed for 5 minutes at a stirring speed of 20 Orpm using the mixer shown in Figure 3, and then immediately poured into a flyback transformer maintained at a vacuum level of 10 m7 fLHg. This was heated and cured at 80° C. for 3 hours.

The resulting flyback transformer operated normally.

Furthermore, when this was disassembled, there were no voids and the impregnation into the secondary coil was good.

Example 2 In order to confirm the effect of the added amount of the organopolysiloxane copolymer of the present invention, the organopolysiloxane copolymer t in the formulation of Example 1 was changed from 0.1 to 30.0 parts, and The effect was confirmed using the same method as in Example 1, and the results shown in Table 1 were obtained.

A silicone rubber composition containing 0.2 parts or more of an organopolysiloxane copolymer is mixed with a mixer shown in FIG.
Even after mixing for 0 minutes, no significant increase in viscosity occurred, and flyback transformers manufactured using these silicone rubbers did not generate corona discharge and had good impregnation properties.

Example 3 The mixture of Example 1 was mixed using the mixer shown in Figure 3 at a mixing ratio of 1=1 and the stirring speed was changed (however, the stirring time was 1.
The results shown in Table 2 were obtained by evaluating the viscosity change (for 0 minutes) and the performance using a flyback transformer.

No influence of stirring speed was observed.

Example 4 Part A and Part B were produced using the same method and composition as in Example 1.

However, this agent contains 3 parts of vinyltriethoxysilane to provide adhesive properties.

The viscosities of agent A and agent B were 35P and 25P, respectively.

When parts A and B were mixed by hand using a spatula at a blending ratio of 1, the viscosity was 30P.

A 1:1 mixture of this human drug and B agent was mixed for 10 minutes at a stirring speed of 200 rpm using the mixer shown in Figure 3, but almost no change in viscosity was observed, and the viscosity after 10 minutes was 32P. .

Next, a flyback transformer was manufactured using the above A and B agents under the same conditions and in the same manner as in Example 1.

The obtained flyback transformer operated normally, and when it was disassembled, no voids were observed, and the impregnation of the secondary coil was good.

Comparative Example 1 Agents A and B were manufactured using the same method and composition as in Example 1.

However, these A and B agents do not contain an organopolysiloxane copolymer.

The viscosities of Part A and Part B were 43 poise and 29 poise, respectively.

When Parts A and B were mixed slowly by hand using a spatula at a blending ratio of 1:1, the viscosity was 35 poise.

On the other hand, when this 1:1 mixture of Parts A and B was mixed for 10 minutes at a stirring speed of 20 Orpm using the mixer shown in Figure 3, an increase in viscosity was observed as shown in curve 17 in Figure 4. .

Next, the results of manufacturing a flyback transformer having the shape shown in FIG. 2 using the above-mentioned agents A and B will be described.

The above 1:1 mixed solution of Part A and Part B was mixed for 5 minutes at a stirring speed of 20 rpm using the mixer shown in Figure 3, and then immediately poured into a flyback transformer maintained at a vacuum degree of 110 mff1H. It was cured by heating at ℃/3h.

When the resulting flyback transformer was operated, corona discharge occurred, causing disturbances on the television screen.

Also, when this was dismantled, voids were found inside.
The impregnation of the secondary coil was incomplete.

Comparative Example 2 Part A and Part B were produced using the same method and composition as in Example 4.

However, this human agent and agent B do not contain an organopolysiloxane copolymer.

The viscosities of Part A and Part B were 3'5P and 25P, respectively.

The viscosity was 3'OP when Parts A and B were mixed slowly by hand using a spatula at a blending ratio of 1:1.

When this 1:1 mixed solution of Part A and Part B was mixed for 10 minutes at a stirring speed of 20 Orpm using the mixer shown in Figure 3, the viscosity increased to 80P.

Next, a flyback transformer was manufactured using the above A and B agents under the same conditions and in the same manner as in Example 1.

When the resulting flyback transformer was operated, corona discharge occurred and the television screen was disturbed.

When this was disassembled, there were voids inside, and the impregnation into the secondary coil was incomplete.

As described above, by manufacturing a flybank transformer according to the present invention, it is possible to efficiently insulate a television flyback transformer that has no internal voids and has good impregnability.

[Brief explanation of drawings]

Figures 1 and 4 show changes in viscosity when the silicone rubber composition is stirred, Figure 2 shows an example of a flyback transformer, and Figure 3 shows the stirring of the silicone rubber composition. This shows an example of a mixer. 1.2, 16, 17: Experimental data, 3: Silicone rubber composition, 4: Case, 5: Secondary coil, 6: Primary coil, 7: Secondary bobbin, 8: Primary bobbin, 9: High pressure Lead wire, 10: Motor, 11: Shaft, 12: Stirring blade, 13: Mixed liquid, 14: A agent, 15: B agent.

Claims (1)

[Scope of Claims] 1. A flyback transformer characterized in that a silicone rubber composition containing the following (a)-(a) as an essential component is stirred, and then vacuum injected into a flybank transformer and then cured. Insulation method. (a) - Diorganopolysiloxane represented by the formula (R in the formula is a substituted or unsubstituted monovalent hydrocarbon group having no aliphatic unsaturated bond, and n is an integer from 50 to 2000) 100 parts by weight, (o) (CH2=CH)00.5 units of R2Si, and R3
5iOo, 5 units and SiO2 unit, and R
35i00.5 units and (CH2=CH) R2S 10
o, the molar ratio of the sum of 5 units and the SiO2 unit is (0,
0.2 to 30 parts by weight of an organopolysiloxane copolymer having the following: (indicates a hydrogen group) (・→ Prepaid 1 molecule in an amount sufficient to provide 0.7 to 5.0 hydrogen atoms directly bonded to a silicon atom per vinyl group in components (1) and (b) an organohydrodiene polysiloxane having three or more hydrogen atoms therein; (b) 50 to 300 parts by weight of a silica filler; (a) a catalytic amount of platinum or a platinum compound.