KR100758316B1 - Self-extinguishing additive RTV-2 silicone rubber composition - Google Patents

Abstract

The present invention relates to a two-part addition type room temperature-curable silicone rubber composition having self-extinguishing properties, and more particularly, to a conventional silicone rubber composition by appropriately using the content of platinum compound, rare earth group metal compound and zinc carbonate while maintaining mechanical properties. It relates to an additive room temperature curing silicone rubber composition having improved self-extinguishing properties.

Self-extinguishing, platinum compound, rare earth metal compound, zinc carbonate

Description

Self-extinguishing additive RTV-2 silicone rubber composition

The present invention relates to an additive-type room temperature-curable silicone rubber composition having self-extinguishing property, and more particularly, by using a content of platinum compound, rare earth group metal compound and zinc carbonate in a conventional silicone rubber composition, while maintaining mechanical properties, self-extinguishing The present invention relates to an additive type room temperature cure silicone rubber composition having improved properties.

Silicone rubber has excellent properties in various aspects such as release property, water repellency, cold resistance, heat resistance, weather resistance, and chemical stability. It has been emerging. However, the composition of the self-extinguishing silicone rubber has been using a platinum compound to increase the price of the silicone rubber, and a low-cost flame retardant was used together to reduce the amount of the platinum compound, but did not exhibit satisfactory flame retardancy.                         

For example, when the platinum compound and carbon black are used together, if the curing agent contains an acyl group, it may cause incomplete curing and adversely affect the electrical properties. When the platinum compound and aerosol titanium oxide are used together, the electrical properties may be affected by humidity. Are affected a lot. In addition, when the platinum compound and the iron oxide system (FeO, Fe ₂ O ₃ , Fe ₃ O ₄ ) is used less, the self-extinguishing properties are unsatisfactory, and when used a lot, the problems that adversely affect the mechanical properties.

Accordingly, the present inventors have used a composition of a room temperature-curable silicone rubber having self-extinguishing property in an appropriate content to improve the self-extinguishing properties and to not lower the mechanical properties including strength, resulting in an environmentally friendly environment. The present invention has been completed by developing a composition of an addition-type room temperature-curable silicone rubber having self-extinguishing property by appropriately using platinum compound, zinc carbonate, and rare earth metal content as a raw material used as a flame retardant based on cotton.

Accordingly, an object of the present invention is to provide a composition of two-part addition type room temperature-curable silicone rubber having self-extinguishing property.

The present invention is represented by the following formula (1), organohydrogen 100 parts by weight of the organopolysiloxane containing a vinyl group 0.05 ~ 0.15 mmol / g, side chain and the end of the organohydrogen containing 4.0 to 8.0 mmol / g of the sock end 2 to 20 parts by weight of polysiloxane, 1 to 100 parts by weight of diatomaceous earth or quartz powder with a particle size of 100 microns or less, platinum compound (which is diluted to 5% or less in organic matter), 0.01 to 0.04 parts by weight, rare earth group metal compound (organic substance) Added to room temperature-curable silicone rubber composition comprising 0.001 to 3 parts by weight, 1 to 30 parts by weight of zinc carbonate, 0.01 to 0.1 parts by weight of platinum catalyst, and 0.01 to 3 parts by weight of curing retardant. It is characterized by.

Referring to the present invention in more detail as follows.

The present invention is a two-part addition type room temperature-curable silicone rubber composition having self-extinguishing property by appropriately using the content of platinum compound, rare earth group metal compound and zinc carbonate in order to improve the self-extinguishing properties while maintaining the mechanical properties in the conventional silicone rubber composition. It is about.

(1) organopolysiloxane

The main raw material of the room temperature-curable silicone rubber is an organopolysiloxane containing an alkenyl group, such as at least two or more vinyls, and the curing proceeds by a crosslinking reaction of the organohydrogenpolysiloxane containing a Si-H group. 100 parts by weight of the organopolysiloxane is used. The organopolysiloxane represented by the following formula (1) has a number average molecular weight of 23,000 to 11,000, and has a vinyl content of 0.05 to 0.15 mmol / g.

RO- (R ' ₂ SiO) nR

In Chemical Formula 1; R is a vinyl group, R 'is a methyl group, n is an integer of 110-250.

(2) organohydrogenpolysiloxane

The organohydrogenpolysiloxane is represented by the following Chemical Formula 2 as a curing agent, the number average molecular weight is 8,000 to 4,000, and has a hydrogen content of 4.0 to 8.0 mmol / g.

The usage-amount is 2-20 weight part with respect to 100 weight part of (1), Preferably it is 10-15 weight part. If the amount is less than 2 parts by weight, there is a problem that the hardening does not occur, and if it exceeds 20 parts by weight, the curing speed is too fast, the workability is lowered, and there is a problem that the product is broken after curing.

RO- (R ₂ SiO) x- (R˝ ₂ SiO) yR

In Formula 2, R is a methyl group, R 'is a hydrogen atom, and x = 50 to 60, y = 60 to 80 is an integer.

(3) extender

Diatomaceous earth or quartz powder is used as an extender, and the particle size is 100 microns or less, preferably 10 microns or less. If the particle size is more than 100 microns, there is a problem that precipitation of the extender occurs during storage after manufacture.                     

The usage-amount is 1-100 weight part with respect to 100 weight part of (1), Preferably it is 75-85 weight part. If the amount is less than 1 part by weight, there is a problem in that it does not act as an extender for the purpose of unit cost reduction, and if it exceeds 100 parts by weight, mechanical properties such as tensile and tear strength are deteriorated.

(4) additives to impart self-extinguishing

(a) platinum compounds

Chloroplatinic acid or chloroplatinic acid compounds mixed with alcohols, ethers, aldehydes and the like and phosphoric acid platinum (Pt {P (OC ₆ H ₅ ) ₃ } ₄ , Pt {P (C ₆ H ₅ ) ₃ } ₄ , Pt {P (CH ₃ ) ₃ } ₄ , Pt {P (C ₄ H ₉ ) ₃ } ₄ , Pt {P (OCH ₃ ) ₃ } ₄ , Pt {P (OC ₆ H ₅ ) ₃ } ₃ , Pt {P (C ₆ H ₅ ) ₃ } ₃ , Pt {P (C ₆ H ₅ ) (C ₂ H ₅ ) ₂ } ₄ , Pt {P (OC ₆ H ₅ ) (OC ₂ H ₅ ) ₂ } ₄ , Pt {P (C ₆ H ₅ ) ₂ (OC ₂ H ₅ )} ₄ , Pt {P (CH ₃ ) ₂ (OC ₄ H ₉ )} ₄ ) and the like. It is used by dispersing in organic solvents such as propyl alcohol, benzene and xylene. Preferably, the isopropyl alcohol is used to dilute the platinum content to 5% or less. The amount of use is 0.01 to 0.04 parts by weight for 100 parts by weight of (1), and preferably 0.03 to 0.04 parts by weight. In this case, if the amount is less than 0.01 parts by weight, the flame retardancy is not improved, and if it exceeds 0.04 parts by weight, the unit price increases.

(b) metal compounds

At least one metal or metal compound was used in combination with the organic compound to improve heat resistance and self-extinguishing and increase dispersibility.                     

(b-1) Rare Earth Metal Compounds

Cerium octoate, cerium acetate, cerium carbonate and the like are used, and cerium octoate is preferable. In particular, it is preferable to dilute cerium octoate using mineral spritz which is a petroleum solvent such that cerium content is 5% or less. The usage-amount is 0.001-3 weight part with respect to 100 weight part of (1), Preferably it is 0.05-1 weight part. In this case, if the amount is less than 0.001 part by weight, there is a problem in that it does not play a role of the heat resistance improver.

(b-2) zinc carbonate

The amount used was 1 to 30 parts by weight in 100 parts by weight (1), preferably 5 to 20 parts by weight. If it is used less than 1 part by weight, there is a problem that does not impart flame retardancy to the product, if it exceeds 30 parts by weight increases the specific gravity and raw material costs, causing mechanical properties deteriorate and in some cases the flame retardancy is rather reduced There is a problem.

(5) catalyst and curing retardant

In addition to the room temperature-curable silicone rubber, a platinum compound is used as a catalyst, and such a platinum catalyst crosslinks an organopolysiloxane including a vinyl group and a hydrogenated polysiloxane. Platinum included in the platinum catalyst also imparts self-extinguishing properties to the silicone rubber.

As a platinum complex used as a catalyst, it has an oxidation number of 0 and forms a complex with a low molecular weight vinylsiloxane in order to increase the reactivity and compatibility with a silicone polymer.

The low molecular weight vinyl siloxane is vinyl tetramethylsiloxane (di-Vinyltetramethylsiloxane) or tetramethyltetravinyl tetracyclosiloxane (Tetramethyltetravinyl tetracyclosiloxane). Platinum content in the platinum compound added with a catalyst is 0.1 to 0.2%, and it is preferable to use 0.01 to 0.1 weight part.

In general, the addition-type room temperature-curable silicone rubber has the advantage of freely controlling the curing rate by adding a curing retarder together with the platinum catalyst. The curing retardant interferes with the reaction of the organopolysiloxane and the hydropolypolysiloxane to slow down the curing rate. The additional room temperature-curable silicone rubber has the advantage of having an appropriate curing rate in terms of workability by controlling the amount of catalyst and the amount of retarder. The curing retardant was 0.01 to 3 parts by weight of tetramethyltetravinyltetracyclosiloxane and the purity was 98% or more.

Hereinafter, the present invention will be described in more detail based on the following examples, but the present invention is not limited thereto.

Production Example

All silicon compounds of Comparative Examples and Examples were prepared in the same manner as follows.

A two-part addition room temperature-curable silicone compound is prepared by dividing into parts A and B. In general, part A includes an organopolysiloxane including a vinyl group, a catalyst, and an additive, and part B includes an organopolysiloxane and a hydrogenated polysiloxane. It was included with the curing retardant to prevent the reaction.

When the two-part addition type room temperature-curable silicone compound was mixed with the A part and the B part, the catalyst contained in the A part caused the reaction between the organopolysiloxane including the vinyl group and the hydrogenated polysiloxane to proceed with curing. The mixing ratio of A part and B part at the time of hardening is 1: 1 by weight ratio.

Example 1

Next, a silicone compound was prepared using the composition components and contents shown in Table 1. Part A includes 50 parts by weight of vinyldimethylpolysiloxane, 45.2 parts by weight of an extender, 0.185 parts by weight of ceroctoate, 7.4 parts by weight of zinc carbonate, 0.037 parts by weight of a platinum compound, and 0.01 parts by weight of a catalyst.

Part B contained 12.6 parts by weight of organohydrogenpolysiloxane, 39.8 parts by weight of an extender, and 0.26 parts by weight of a curing retardant to 50 parts by weight of vinyl dimethylpolysiloxane.

Part A and part B were mixed in a mixing vessel in a weight ratio of 1: 1 with a spatula, and then degassed in a vacuum of 60 cmHg. Degassing | defoaming is for removing the air contained in mixing, and defoaming for 3-5 minutes.                     

The defoamed compound was poured into a mold of 10 cm × 25 cm × 2 mm, cured, and prepared into a specimen.

Example 2

In Example 1, the amount of organohydrogenpolysiloxane added was increased to 12.8, and zinc carbonate was increased to 11.1. The other manufacturing method was the same as in Example 1 above.

Example 3

In Example 1, the amount of organohydrogenpolysiloxane added was increased to 13.1, and zinc carbonate was increased to 14.8. The other manufacturing method was the same as in Example 1 above.

Comparative Example 1

The platinum compound, cerium octoate, and zinc carbonate, which are flame retardant additives, were not added.

Comparative Example 2

Among the additives of Example 1, the platinum compound as a flame retardant additive was not added. Part A and part B were tested to have a weight ratio of 1: 1 including only the added additives.

Comparative Example 3

Among the additives of Example 1, cerium octoate, which is a flame retardant additive, was not added, except that the manufacturing method was performed in the same manner as in Example 1.

Comparative Example 4

Among the additives of Example 1, zinc carbonate, which is a flame retardant additive, was not added, except that the manufacturing method was performed in the same manner as in Example 1.

In the mechanical property test, tensile and tear specimens were tested according to KS M 6518 to test specimens of 2 mm thickness. The flame retardancy test was tested with 3 mm specimens based on UL94V-0.

Classification (parts by weight) Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Example 1 Example 2 Example 3 Dimethyl Polysiloxane 100 100 100 100 100 100 100 Organohydrogenpolysiloxane 12.6 12.6 12.6 12.6 12.6 12.8 13.1 extender 85 85 85 85 85 85 85 Platinum compounds (diluted with 5% platinum content) - - 0.037 0.037 0.037 0.037 0.037 Cerium octoate (diluted with 5% cerium content) - 0.185 - 0.185 0.185 0.185 0.185 Zinc carbonate - 7.4 7.4 - 7.4 11.1 14.8 catalyst 0.01 0.01 0.01 0.01 0.01 0.01 0.01 Curing retardant 0.46 0.46 0.46 0.46 0.46 0.46 0.46

Self-extinguishing measurement result division Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Example 1 Example 2 Example 3 Total combustion time (seconds) 29 21 19 23 4.4 3.0 5.6 * Each sample was burned twice in succession for 10 seconds to measure the time to turn off and the summed time was expressed as the average of five specimens.

Mechanical property measurement result division Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Example 1 Example 2 Example 3 Tensile Strength (Kg / cm2) 32.9 30.1 28.5 31.0 29.5 32.0 32.9 Tear strength (Kg / cm) 5.29 5.50 5.03 5.12 5.50 7.00 6.25 % Elongation 110.6 105.1 98.2 100.9 98.3 105.9 89.6 importance 1.35 1.37 1.37 1.36 1.37 1.38 1.39 Shore A 49 53 53 53 53 53 54

As shown in Table 2 and Table 3, the mechanical properties were not significantly different between the Examples and Comparative Examples, the self-extinguishability of the Comparative Example in the measurement of self-extinguishing did not pass the UL94V-0 certification value, Example All of the self-extinguishing meeting the UL94V-0 certification.

As described above, the present invention improves the insufficient effect of the flame retardant by appropriately using the content of platinum compound, rare earth group metal compound and zinc carbonate in the conventional silicone rubber composition, and has self-extinguishing property that does not lower the mechanical properties. It relates to an additive room temperature curing silicone rubber composition.

The present invention relates to the composition of a two-component room temperature-curable silicone rubber is to impart flame retardancy without deteriorating the mechanical properties of the conventional two-component room temperature-curable silicone rubber. Such flame retardant properties can be applied to two-component additive-type room temperature curing products for electric and electronic potting, where demand is increasing among silicone application properties. Potting products for electric and electronics are used for the sealing of hybrid ICs for automobiles, air conditioners, power modules for NC machines, and sealing of various sensors.

Claims (1)

100 parts by weight of an organopolysiloxane comprising a vinyl group at 0.05 to 0.15 mg / mol at the sock end, and an organohydrogenpolysiloxane 2 to 4.0 to 8.0 mg / mol at the side chain and sock end. 20 parts by weight, 1 to 100 parts by weight of diatomaceous earth or quartz powder with a particle size of 100 microns or less, platinum compound (which is diluted to 5% or less in organic matter) 0.01 to 0.04 parts by weight, rare earth group metal compound (5% in organic matter) Dilute to 0.001 to 3 parts by weight, 1 to 30 parts by weight of zinc carbonate, 0.01 to 0.1 parts by weight of catalyst, and 0.01 to 3 parts by weight of curing retardant. . Formula 1 RO- (R ' ₂ SiO) nR In Chemical Formula 1; R is a vinyl group, R 'is a methyl group, n is an integer of 110-250.