JPH07122020B2 - Room temperature curable organopolysiloxane composition and cured product thereof - Google Patents

Description

The present invention relates to a room temperature curable organopolysiloxane composition, particularly for electronic parts because it exhibits excellent flame retardancy and does not corrode metal. The present invention relates to a room temperature curable organopolysiloxane composition that is useful as a product and a cured product thereof.

(Prior Art) Room-temperature curable compositions containing diorganopolysiloxane as a main component have excellent heat resistance, electrical properties, and adhesive properties, and are therefore widely used for electrical / electronic parts, particularly for adhesive sealing thereof. Has been done.

For this composition, in order to improve safety and reliability, platinum is often added to the composition to impart flame retardancy to the composition.

(Problems to be solved by the invention) However, since platinum added to impart flame retardancy is usually an alcohol solution of chloroplatinic acid, it is used in electronic parts by the hydrochloric acid contained therein. There is a problem that metal wires and metal plates are corroded, and in order to solve this problem, chlorine-free olefin platinum complex etc. should be used, but this reduces flame retardancy. This has the drawback of not being practical.

(Means for Solving the Problem) The present invention relates to a room temperature curable organopolysiloxane composition and a cured product thereof, in which such disadvantages are solved. A) Both ends of a molecular chain are hydroxyl groups or alkoxysilyl groups. Alternatively, 100 parts by weight of diorganopolysiloxane blocked with vinyloxysilyl group, B) specific surface area of 30 m
1 to 20 parts by weight of reinforcing silica powder of ² / g or more, C) 10 to 200 parts by weight of zinc carbonate or basic zinc carbonate, D) 10 to 200 parts by weight of quartz powder, and E) substantially containing chlorine atom. Platinum or a platinum compound in an amount of 1 to 2,000 ppm as the platinum atom based on the component A), F) an amine or ammonia hydrochloride of 0.5 parts by weight or more in an equimolar amount or more to the platinum as the component E). G) A room temperature curable organopolysiloxane composition, which comprises 0.01 to 5 parts by weight of a curing catalyst, and a cured product obtained by curing the same.

That is, as a result of various investigations by the present inventors to develop a room temperature curable organopolysiloxane having excellent flame retardancy and exhibiting no corrosive property, the known room temperature curable organopolysiloxane composition was flame retarded. Zinc carbonate and quartz powder are added as an agent, and if it is combined with platinum or a platinum compound that does not substantially contain chlorine and lead chloride of amine or ammonia, it has excellent flame retardancy and does not show corrosiveness. The present invention was completed by finding out that products can be obtained, and conducting research on these types, compounding amounts, and the like.

These will be described in more detail below.

(Function) The present invention relates to a room temperature curable organopolysiloxane composition having excellent flame retardancy and exhibiting no corrosive property, and a cured product thereof.

The organopolysiloxane as the component A) constituting the composition of the present invention is the main ingredient of the composition of the present invention. R is a methyl group, an ethyl group, a propyl group, a butyl group, a 2-ethylbutyl group, an alkyl group such as an octyl group, a cycloalkyl group such as a cyclohexyl group, a cyclopentyl group, a vinyl group, an allyl group, a hexenyl group, and the like. Alkenyl group, phenyl group, aryl group such as tolyl group, naphthyl group, aralkyl group such as diphenyl group or some or all of hydrogen atoms bonded to carbon atoms of these groups are substituted with halogen atom, cyano group, etc. Identical or different unsubstituted or substituted carbon atoms of 1 to 1 selected from chloromethyl group, 3,3,3-trifluoropropyl group, 2-cyanoethyl group, 3-cyanopropyl group, etc.
0, preferably a monovalent hydrocarbon group having 1 to 8 carbon atoms, a is
It is said to be a number of 1.90 to 2.05, which is an essentially linear diorganopolysiloxane which may have a branched structure in a part thereof. Group, a lower alkoxy group such as an ethoxy group, or a vinyloxy group having 2 to 3 units, which is blocked with a methyldialkoxysilyl group, a trialkoxysilyl group, a methyldivinyloxysilyl group, a trivinyloxysilyl group, etc. It Further, this means that the cured product obtained from this has good elasticity and mechanical strength, so that the viscosity at 25 ° C. is 25 to 1,000,000 cS, particularly 500 to 100,
It is preferably 000 cS.

Further, the reinforcing silica powder as the component B) constituting the composition of the present invention is an essential component for making the silicone rubber obtained by curing the composition excellent in mechanical strength. However, this must have a specific surface area of 30 m ² / g or more in order to achieve its purpose,
This includes fumed silica, precipitated silica, or hexamethyldisilazane or dimethyldichlorosilane on its surface.
A representative one is one that has been hydrophobized with methyltrichlorosilane or the like. The amount of the reinforcing silica powder added is less than 1 part by weight based on 100 parts by weight of the organopolysiloxane as component A), and the reinforcing effect is not achieved. Since the viscosity of the product becomes too high and the workability deteriorates, it is necessary to set it in the range of 1 to 20 parts by weight, but this preferable range is 3 to 10 parts by weight.

Next, zinc carbonate or basic zinc carbonate as the component C) constituting the composition of the present invention has the chemical formula ZnCO ₃ or ZnCO ₃ ·.
It is represented by Zn (OH) ₂ , which is an essential component for imparting flame retardancy to the composition of the present invention. If it is less than 10 parts by weight with respect to 100 parts by weight of polysiloxane, the composition will be too small to exhibit good flame retardancy,
If the amount is more than 200 parts by weight, the silicone rubber obtained by curing this composition lacks elasticity.
It should be in the range of 0 parts by weight, but the preferred range is 50 to 100 parts by weight.

Further, the quartz powder as the component D) constituting the composition of the present invention is also an essential component for imparting flame retardancy to the composition of the present application, like the component C) described above. May have a particle size of 0.01 to 20 μm, preferably 0.1 to 10 μm. If the addition amount is less than 10 parts by weight with respect to 100 parts by weight of the organopolysiloxane as the component A), the composition is too small. The product does not exhibit good flame retardancy, and if it exceeds 200 parts by weight, the silicone rubber obtained by curing this composition will lack elasticity, so it is necessary to set it to 10 to 200 parts by weight. A preferred range is 50 to 100 parts by weight.

Further, platinum or a platinum compound as the component E) constituting the composition of the present invention is also an essential component for making the composition of the present invention flame-retardant, which is the composition of the present invention. It is necessary to substantially contain no chlorine element in order to show no corrosiveness. This substantially platinum-free platinum compound is produced, for example, by reacting chloroplatinic acid with ethylene, cyclooctadiene or vinyl group-containing siloxane, and then removing hydrogen chloride with amine, alkali metal carbonate or the like. It should be done. The addition amount is less than 1 ppm with respect to 100 parts by weight of the organopolysiloxane as the component A), and the composition of the present application does not show flame retardance, and the addition amount is 2,000 ppm.
Since the flame retardancy does not change even if the amount is larger and it is economically disadvantageous, it is necessary to set the range of 1 to 2,000 ppm, but the preferable range is 10 to 200 ppm.

Next, the hydrochloride of amine or ammonia as the component F) constituting the composition of the present invention is also an essential component for imparting flame retardancy to the composition of the present invention.
NH ₄ Cl, (CH ₃ ) ₃ N HCl, (C ₂ H ₅ ) ₃ N HCl, (C ₃ H ₇ ) ₃ N
・ HCl, (C ₄ H ₉ ) ₃ N ・ HCl, (C ₂ H ₅ O) ₃ SiC ₃ H ₆ NH ₂ · HCl, (CH ₃ O) ₃ -SiC ₃ H ₆ NHC ₂ H ₄
NH ₂ · HCl and the like are exemplified, but the hydrochlorides of these amines or ammonia are considered to improve flame retardancy by forming an equimolar complex with the above-mentioned platinum atom. Is required to be at least equimolar to the platinum atom as the above-mentioned component F),
Organopolysiloxane 100 as component A)
If the amount is more than 0.5 parts by weight, the electrical characteristics of this composition will be deteriorated. Therefore, it is necessary that the amount is at least equimolar to the platinum atom as the component E) and at most 0.5 parts by weight.

As the curing catalyst as the component G) constituting the composition of the present invention, various known catalysts conventionally used in this type of composition can be used, and for example, lead-containing catalyst can be used.
2-ethyloctoate, dibutyltin diacetate, dibutyltin dilaurate, butyltin-2-ethylhexoate, iron-2-ethylhexoate, cobalt-2-ethylhexoate, manganese-2-ethylhexo Ate, stannous caprylate, tin naphthenate, tin oleate,
Metal salts of organic carboxylic acids such as tin butyrate, titanium naphthenate, zinc naphthenate, cobalt naphthenate, zinc stearate; tetrabutyl titanate, tetra-2-ethylhexyl titanate, triethanolamine titanate, tetra (isopropenyloxy) Organic titanates such as titanates; organosilochitanes, β-
Organic titanium compounds such as carbonyl titanium; alkoxy aluminum compounds, aminoalkyl group-substituted alkoxysilanes such as 3-aminopropyltriethoxylane, N- (trimethoxysilylpropyl) ethylenediamine;
Amine compounds such as hexylamine and dodecylamine phosphate and salts thereof; quaternary ammonium salts such as benzyltriethylammonium acetate; lower fatty acid salts of alkali metals such as potassium acetate, sodium acetate, lithium oxalate; dimethylhydroxylamine, diethyl Dialkylhydroxylamine such as hydroxylamine; the following formula, The guanidine compound represented by and the guanidyl group-containing silane or siloxane; and the like can be used alone or in combination of two or more kinds.

If the amount of the curing catalyst added is less than 0.01 parts by weight with respect to 100 parts by weight of the organopolysiloxane as the component A), it will take a long time to cure the composition. In some cases, it tends to be difficult to uniformly cure even deeper, and if it exceeds 5 parts by weight, the time required for forming a film becomes extremely short, which causes inconvenience on the work surface. Since the cured product obtained tends to have inferior properties such as heat resistance and weather resistance, it is necessary to use 0.01 to 5 parts by weight, but the preferred range is 0.1 to 3 parts by weight.

The room-temperature-curable organopolysiloxane composition of the present invention can be obtained by uniformly mixing the above-mentioned components A) to G) in a predetermined amount. An organic silicon compound having at least three hydrolyzable groups in the molecule or a partial hydrolyzate thereof may be added as a cross-linking agent, which makes it possible to easily cure the composition at room temperature. . Examples of the hydrolyzable group include an acyloxy group, a ketoxime group, an alkoxy group, an alkenyloxy group, an amino group, an aminoxy group, and an amide group.As the organic silicon compound having such a hydrolyzable group, , For example, methyltrimethoxysilane, vinyltriethoxysilane, 3
-Alkoxysilanes such as chloropropyltrimethoxysilane and 3-aminopropyltriethoxysilane; ketoxime silanes such as methyltris (dimethyloxime) silane, methyltris (methylethylketoxime) silane, tetra (methylethylketoxime) silane; vinyltriacetoxysilane, Alkenyloxysilanes such as methyltriacetoxysilane and methyltriisoptenyloxysilane; amide silanes such as phenyltris (N-methylacetamido) silane and vinyltris (N-ethylacetamido) silane; vinyltris (N-butylamino) silane, phenyltris (N, N-
Aminosilanes such as diethylamino) silane; methyltris (N, N-dimethylaminooxy) silane, vinyltris (N, N-diethylaminooxy) silane and other aminosilanes;
These can be used alone or in combination of two or more, but if the amount is less than 0.5 parts by weight relative to 100 parts by weight of the organopolysiloxane as the component A), curing of the composition is effective. 0.5 to 50 parts by weight because the physical properties of the obtained cured elastic body may be deteriorated or it may be economically disadvantageous if it is blended in a larger amount than 50 parts by weight. It is good to say

In the organopolysiloxane composition of the present invention thus obtained, the organopolysiloxane as the component A) has a hydroxyl group, an alkoxysilyl group or a vinyloxysilyl group at the end of the molecular chain, and the component G) is added to this. As a curing catalyst is added as this, when left in the air, it cures at room temperature due to moisture in the air to become a silicone rubber cured product. As zinc carbonate, quartz powder, platinum or a platinum compound, which shows excellent flame retardancy because it contains an amine or ammonia hydrochloride, since the platinum or platinum compound added here does not contain a chlorine atom, It has the advantage that it is not corrosive.

(Examples) Next, examples of the present invention, comparative examples will be given. In the examples, parts are parts by weight, and viscosity is a measured value at 25 ° C. Flame retardancy and corrosion resistance are as follows. The results are shown in FIG.

[Flame retardancy] Tested by a test method in accordance with UL-94.

[Corrosion] Tested by a test method according to MIL-A-46146A.

Examples 1 to 3, Comparative Examples 1 to 2 Molecular chain ends are blocked with a trimethoxysilyl group,
100 parts of dimethylpolysiloxane with a viscosity of 10,000 cS, surface-treated with hexamethyldisilazane, reinforcing silica powder with a specific surface area of 130 m ² / g, zinc carbonate powder, quartz powder, crystallite VZS-2 [( Tatsumori Co., Ltd.], a platinum-ethylene complex obtained by reacting chloroplatinic acid with ethylene and dehydrochlorination, triethylamine hydrochloride and dibutyltin dioccate were added in the amounts shown in Table 1 to give organopoly. When Siloxane Compositions I to III were prepared and left at room temperature for 48 hours, they were cured into a silicone rubber, so the physical properties of this rubber were examined by the method according to JIS K-6301 and the flame retardancy of this rubber was examined. When corrosiveness was examined, the results as shown in Table 1 were obtained.

However, for comparison, reinforcing silica powder, zinc carbonate, quartz powder, triethylamine hydrochloride and cibutyltin dioctate were added in the amounts shown in Table 1 as above, but instead of the platinum-ethylene complex in the above. The isopropyl alcohol solution of chloroplatinic acid (platinum content: 2% by weight) was added in the amount shown in Table 1 to prepare organopolysiloxane compositions IV to V, and the rubber physical properties of the silicone rubber cured at room temperature. The flame retardancy and corrosion resistance were examined, and the results were as shown in Table 1.

Examples 4 to 7 and Comparative Examples 3 to 4 100 parts of dimethylpolysiloxane whose molecular chain end was blocked with a trimethoxysilyl group used in Example 1 was added to a reinforcing silica having a specific surface area of 130 m ² / g, and a base. Zinc carbonate, quartz powder / crystallite VXS-2 (supra), platinum-ethylene complex (supra), triethylamine hydrochloride, tetrabutoxytitanium or tetrapropoxytitanium and methyltrimethoxysilane or vinyltrimethoxysilane second The amounts shown in the table were added and mixed homogeneously to make organopolysiloxane compositions VI-IX, which were enclosed in a container.

Then, these compositions were taken out of the container and allowed to stand in the air for 24 hours.Since all of them were cured by moisture in the air to become silicone rubber, their flame retardancy and corrosiveness were examined. However, the result as shown in Table 2 was shown.

However, for comparison, in the above description, reinforcing silica, basic zinc carbonate, platinum-ethylene complex, triethylamine hydrochloride, tetrabutoxytitanium, and methyltrimethoxysilane were added, but the organopolysiloxane composition X was added without adding quartz powder. In addition to the above, reinforcing silica, quartz powder, platinum-ethylene complex, triethylamine hydrochloride, tetrabutoxytitanium, and methyltrimethoxysilane were added in the above, but the organopolysiloxane composition XI was added without adding basic zinc carbonate. When the silicone rubber obtained by curing these was prepared and examined for flame retardancy and corrosion resistance, the results as shown in Table 2 were obtained.

(Effects of the Invention) The present invention relates to a room temperature curable organopolysiloxane composition which is excellent in flame retardancy and gives a silicone rubber which does not show corrosive properties, and a cured product thereof. Diorganopolysiloxane blocked with hydroxyl groups or 2 to 3 alkoxy or vinyloxy groups, B) reinforcing silica powder, C) zinc carbonate or basic zinc carbonate, D) quartz powder, E) substantially chlorine atom An organopolysiloxane composition comprising platinum or a platinum compound which does not contain F, an amine or ammonia hydrochloride, and G) a curing catalyst, and a cured product obtained by curing the same are summarized. According to this, a hydroxyl group, an alkoxy group at the end of the molecular chain as the component A),
Since a curing catalyst as component G) is added to an organopolysiloxane having a vinyloxy group, when this is left in the air, it cures at room temperature due to moisture in the air to give a silicone rubber cured product. The silicone rubber thus obtained is zinc carbonate as component C), D)
Since it contains quartz powder, E) platinum or platinum compound containing no chlorine atom, and F) amine or ammonia hydrochloride, it has excellent flame retardancy and has no industrial corrosiveness. As such, it is particularly useful for electronic components where it is desired to be flame retardant and not corrosive.

Claims (3)

[Claims] 1. A) 100 parts by weight of a diorganopolysiloxane whose both molecular chain ends are blocked with a hydroxyl group, an alkoxysilyl group or a vinyloxysilyl group, and B) a reinforcing silica powder 1 having a specific surface area of 30 m ² / g or more.
20 parts by weight, C) 10 to 200 parts by weight of zinc carbonate or basic zinc carbonate, D) 10 to 200 parts by weight of quartz powder, E) Substantially no chlorine atom, A) as platinum atom
Platinum or platinum compound in an amount of 1 to 2,000 ppm with respect to the components, F) 0.5 or more parts by weight of an equimolar amount of platinum as the E) component and not more than 0.5 parts by weight of amine or ammonia G) Curing catalyst 0.01 to 5 parts by weight And a room temperature curable organopolysiloxane composition. 2. An organosilicon compound having at least three hydrolyzable groups in one molecule or a partial hydrolyzate thereof,
The room temperature curable organopolysiloxane composition according to claim 1, wherein 0.5 to 50 parts by weight is added to 100 parts by weight of the component A). 3. A cured product obtained by curing the composition according to claim 1 or 2.