JPS601892B2 - Semi-cured silicone rubber molded products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semi-cured silicone rubber molded article, particularly a semi-cured insulating tape or sealing tape.

Conventionally, for insulating and sealing electrical equipment, B stage is used to impregnate glass cloth, glass mat, non-woven fabric, laminated mica, polyester cloth, etc. with varnish such as silicone resin, epoxy resin, phenol resin, alkyd resin, etc. Insulating tape or sealing tape was used.

However, these have the drawbacks of insufficient flexibility and short service life.

The present invention solves the drawbacks of these conventional insulating tapes, and consists of 10 parts by weight of diorganopolysiloxane having a viscosity of at least 1,000,000 centistokes at 25 qo. has at least two vinyl groups directly bonded to the atom, and 2
Vinyl group-containing olga/polysiloxane 5-5 having a viscosity of 100-500,000 centistokes at 5o0
Weight of 8 In one molecule, for one vinyl group directly bonded to an elementary atom in the {o} component, there is a hydrogen atom bonded to an elementary atom in this poppy. liquid organohydrogenpolysiloxane Q inorganic filler in an amount sufficient to provide 0.5 to 1.2 pieces of
10-20 parts by weight Catalytic amount of platinum or platinum compound N Organic peroxide 0.
1 to 5 parts by weight and blowing agent
After shaping a mixture consisting of 0 to 15 parts by weight, 80 parts by weight
This invention relates to a silicone rubber molded product that is cured to a semi-cured state at a temperature of 0.degree. C. or lower.

The semi-cured silicone rubber molded products of the present invention, such as insulating tapes and sealing tapes (hereinafter referred to as insulating tapes, etc.), are composed of an addition-type liquid silicone rubber that cures at relatively low temperatures, a peroxide-curing silicone rubber that cures at high temperatures, and It is mainly composed of fillers and other ingredients, and after uniformly mixing the above-mentioned components {A) to
By flooding the tape to a temperature not exceeding 100 ℃, it is made into a semi-cured state, that is, a tape-like product that has no surface adhesion and has sufficient strength for handling.

The semi-cured product thus obtained is easy to handle and can be stored stably for a long period of time. After the above semi-cured tape is wound or attached to the object to be insulated or sealed, it is heated above the decomposition temperature of the N component to completely cure it and at the same time bond the tapes together. It is also used to insulate or seal by adhering it to an adherend.

To explain the present invention in detail below, the diorganopolysiloxane used in the present invention as a component has an average compositional formula of RaSi04-a (where R represents an alkyl group, a halogenated alkyl group, a vinyl group, or an allyl group). represents, a is 1.9~
2.01), which is required to have a viscosity of at least 1,000,000 centistokes (25 ○) in order to obtain insulating tapes etc. with excellent mechanical strength.

In addition, poppy, the content of vinyl groups bonded to elementary atoms is 0.0
It is preferable that the content be in the range of 25 to 3 mol % in order to impart good properties such as curability, heat resistance, and elasticity to this polysiloxane. Also {mouth) poppy in one molecule as an ingredient,
Organopolysiloxane having at least two vinyl groups directly bonded to elementary atoms is an essential component in order to obtain the desired semi-cured molded product. For example, it has the general formula (where R and RI are It is a polysiloxane represented by an alkyl group, a halogenated alkyl group, an aryl group, a vinyl group, n is an integer of 10 or more.

This material has a density of 100 to 500,000 centistokes (
25qC) is required. The blending amount of this [low component] is 5 to 8 parts by weight, preferably 15 to 4 parts by weight, per 100 parts by weight of the 'A' component. A semi-cured molded product obtained by curing only component 8, such as an insulating tape, will remain sticky on the surface and will not have sufficient strength, making it difficult to handle. [When blending with component A, it sticks to rolls for moat kneading, etc., reducing workability, and after final curing [curing of component component A], the adhesion between insulating tapes, etc., and its machine This is because the strength is reduced. One component of fluid organohydrogenpolysiloxane having at least three Si-day bonds in one molecule has an average composition formula of RaHbSi04-ab (where R is an alkyl group or a halogenated alkyl group). , pinyl group, allyl group, ISa mi2, 0<b≦2, 1<a0bS2.
7), and more specifically diorganopolysiloxanes, dimethylsiloxane units (or methylphenyl siloxane units) whose molecular chain ends are dimethylhydrogensilyl groups and at least one methylhydrogensiloxane unit in the main chain. siloxane units), copolymers of methylhydrogensiloxane units and trimethylsiloxane units, and low-viscosity fluids composed of dimethylhydrogensiloxane units and Si02 units.

These should be blended in an amount sufficient to provide 0.5 to 1.2 moles of hydrogen atoms bonded to the poppy atoms in the raw ingredient per 1 mole of vinyl groups directly bonded to the poppy atoms in the raw component. is required.

The inorganic filler of component 0 may be a known one used in silicone rubber, such as fumed silica, fine silica powder such as silica air gel, quartz powder, titanium white, alumina, iron oxide, carbon black, etc. One or more of these may be used in combination.

The blending amount of this inorganic filler is the same as the above component 10.
The proportion is 10 to 20 parts by weight. It is also optional to add pigments for the purpose of coloring the pond. The platinum or platinum-based compound as the component is required to promote the addition reaction of the thorn component in component [o},
Examples of these include elemental platinum, chloroplatinic acid, platinum olefin complex, platinum aldehyde complex, platinum ketone complex, platinum alcohol compound, etc., and these are used in an amount of 5 to 100 pm, depending on the amount.

The organic peroxide as the N component is used to harden the organopolysiloxane (i.e., to achieve complete hardening). Examples include mil peroxide, bis-2,4-dichlorobenzoyl peroxide, and tert-butyl perbenzoate, which are used in an amount of approximately 0.1 to 5 parts by weight based on component (i). ) The foaming agent as a component does not foam at temperatures below 80○, foams only when the decomposition temperature of the N component is reached, and does not interfere with the curing reaction caused by addition with the thorn component. nitroso compounds such as N.N'
Examples include -dinitrosobentamethylenebentamine, N.N'-dimethyl-N.N'-dinitrosoterephthalamide, and azo compounds such as azobisformamide and azobisisobutyronitrile.

Therefore, the semi-cured silicone rubber molded article of the present invention can be obtained by first uniformly mixing the (I--day components or further W component),
It can be obtained by incompletely curing at a temperature of 8,000 ℃ or less, but the order of this blending is to thoroughly mix the components [A' to desirable.

This mixture is then shaped into a desired shape, but this is an addition reaction catalyst between the low component and one component. Alternatively, it is necessary to form the product into a tape or the like immediately after mixing the 'a)~N component or 'g} component, and make it into a semi-cured molded product at room temperature or by overflowing as appropriate. This shaping method (for example, when forming into a sheet) involves, for example, extrusion or dispensing the topping with a calender roll to form a sheet of the desired thickness, which is then heated to room temperature or a temperature not exceeding 80°C. By the treatment, an addition reaction between the first component and the [o' component is carried out, and the curing of the [A component] is not caused, and if the [T' component is mixed, foaming is not caused. This is a semi-hard IA sheet.In this way, a sheet with no surface tackiness and sufficient strength for handling can be obtained, but if necessary, slits can be made in the middle of this sheet to form the desired shape. Next, to explain how to use the semi-cured tape obtained as described above, first, this semi-cured tape is wound around the object to be insulated so that a part of it overlaps, or The adhesive adheres to the object to be sealed, but at this time, it is desirable to treat the surface of the object and the object with a primer, if necessary.

This primer effect can be imparted by adding an alkyl titanate such as Ti (OCH2C) in advance when mixing the composition.
It is also possible to use a method of mixing H2CQC 3)4 and silicone peroxide, for example, and by doing so, it can be easily adhered to an object to be insulated.

This semi-cured tape wound or adhered to the object to be insulated, etc. is then heated to a temperature of 100 mm or more for an appropriate time to cause curing of the [A] component by the N component, and at the same time, the tape is cured. Adhesion is performed to the overlapping portion of the insulator and to the object to be insulated.

In addition, when this semi-cured tape contains component (T'), foaming occurs simultaneously with the crosslinking and curing reaction of component (A') due to the decomposition of N component, making it more preferable as a sealing material.

The heat curing method includes leaving the tape in a heating furnace, curing it continuously in a heating furnace, or, if the tape is large, by directly blowing hot air onto the semi-cured tape.

As explained above, the semi-cured tape of the present invention is flexible, and since what remains in it is peroxide that reacts at high temperatures, it can be used for a relatively long period of time. If it is wrapped around an insulator under tension during use, it will remain in close contact with the insulator as if it were glued even after it is completely cured, so it is not necessarily necessary to treat the surface of the insulator with a primer. When used as a material, it is extremely easy to insulate and seal, as it can be completely cured and bonded by applying hot air after adhesion, so its industrial value is extremely high.

EXAMPLES Next, the present invention will be described in more detail with reference to Examples.

Example 1 Viscosity 40000, consisting of 99.85 mol% dimethylsiloxane units and 0.15 mol% methylvinisiloxane units.
10 parts by weight of methylvinylpolysiloxane raw rubber with a specific surface area of 200 centistokes (250C), 40 parts by weight of fumed silica with a specific surface area of 200, dimethylpolysiloxane whose molecular chain terminal is a dimethylvinylsilyl group, and trimethylsiloxane units. It consists of methylvinylsiloxane units and Si02 units (0.8 trimethylsiloxane units and methylvinylsiloxane units per Si02 units.

The xane unit is 7 mol% of Si atoms) and the copolymer is 4:1.
30 parts by weight of a mixture of 30 parts by weight of chloroplatinic acid (in terms of Pt), consisting of Si02 units and dimethylhydrogensiloxane units (contains an average of 2 units of dimethylhydrogensiloxane for 1 unit of Si02), viscosity 2.5 parts by weight of a 10 centistoke (25oo) copolymer and 1.5 parts by weight of 2,4-dichlorobenzoyl peroxide were uniformly mixed. Using a calender roll, apply the above composition to a polyester sheet with a thickness of 0.125 mm and a medium thickness of 20 mm, topping it on one side, and place it in a heating oven maintained at 60 mm for 30 minutes. A semi-cured sheet was obtained.

Further, this sheet was slit into two pieces, and then peeled off from the polyester sheet. The physical property shield of this material was as shown in Table 1 (the physical property shield was measured using JISK
6301). Next, a portion of this semi-cured tape was placed under tension on two aluminum tubes, one with a primer treatment and the other untreated, with a diameter of 2 mm and a length of 300 mm. After wrapping it so that it overlapped and fixing the ends, it was left in a 20,000° heating oven for 10 minutes to be completely cured. The physical properties of this product were as shown in Table 1. The baby portion of this fully cured tape adhered completely, and the tape completely adhered to the primer-treated aluminum tube. Also, even though the tape is not attached to the unprimed aluminum tube, the tape is wrapped under tension, so the tube will not come off and will remain in the same state as if the tape were attached. there were. For comparison, the withstand voltage was compared with that of the above-mentioned aluminum coated in a tube shape with one side thickness using the same raw material as the tape of the present invention, and no difference was observed. Table 1 Example 2 A composition obtained by adding 2 parts by weight of azobisisobutyronitrile powder as a blowing agent to the blended composition obtained in the same manner as in Example 1 was spread on a polyester sheet in the same manner as in Example 1. The topping was distributed according to the thickness and cured under the same conditions as in Example 1,
A semi-cured sheet was obtained.

This was then slit into two ends to form a semi-cured tape. Note that the polyester sheet was not peeled off from this tape. The physical properties of this tape were as shown in Table 2. Primer-treated semi-cured tape with this polyester sheet has a thickness of 1 side, 2 sides, and a length of 300 mm.
Semi-hardened tape on skin stainless steel plate.

The surfaces were laminated and crimped at a pressure of 5k9', then held at a pressure of 1 kg/flow, foamed and cured in a heating oven at 20,000 ℃ for 10 minutes, bonded, taken out from the heating oven, peeled off the polyester sheet, and foamed. A sponge tape adhered to a stainless steel plate with a magnification of 2.5 times was obtained. The physical properties of this sponge tape were as shown in Table 2. Table 2 ′

Claims (1)

[Claims] 1 (a) Viscosity at 25°C is at least 10,000
100 parts by weight of diorganopolysiloxane (b) having a viscosity of 100 to 500,000 centistokes at 25°C and having at least two vinyl groups directly bonded to silicon atoms in one molecule; 5 to 80 parts by weight of a group-containing organopolysiloxane (c) having at least three Si-H bonds in one molecule; (b) per vinyl group directly bonded to a silicon atom in the component; The hydrogen atom bonded to the atom is 0.5 to 1.
Liquid organohydrodiene polysiloxane in an amount sufficient to provide 2 pieces (d) 10 to 200 parts by weight of an inorganic filler (e) A catalytic amount of platinum or a platinum compound (f) 0.1 to 5 parts by weight of an organic peroxide A silicone rubber molded product obtained by shaping a mixture consisting of 0 to 15 parts by weight of a blowing agent and (g) a blowing agent, and then curing the mixture to a semi-cured state at a temperature of 80° C. or lower.