RU2505569C1 - Organosilicon composition - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: composition consists of 90-96 wt % of a base - mixture of polydimethylsiloxane (40-60 wt %) and polymethylphenylsiloxane (60-40 wt %) liquid with viscosity of 3000-40000 mm²/s at temperature of 20°C and 4-10 wt % thickener - silicon dioxide. The composition has a refraction index of 1.4100-1.4300, penetration value of 160-280 units, and operates in the temperature range from (-70°C) to (+300°C).

EFFECT: improved properties of the composition.

2 tbl, 12 ex

Description

The present invention relates to organosilicon compositions that find their application in optics, in particular for connecting, sealing and sealing glass optical elements of various optical devices.

The components of some nodes of optical systems (lenses, eyepieces, wrapping systems, achromatic wedges, complex prisms, mirror reflectors, light filters, polaroids, grids, etc.) are connected together in monoblocks. As a connecting substance, various organosilicon compounds are used, which can improve the manufacturability of structures and operational characteristics of optical systems. There are many connection methods, such as bonding, sintering, optical contact, welding and soldering. In this case, the connecting substance must satisfy the following requirements: do not change the optical properties of the connected parts, provide sufficient mechanical, chemical, thermal and light strength of the connection.

As an optical contact between the light source and the photomultiplier, organosilicon lubricant compositions are used that provide maximum light transmission in the contact, are stable in the temperature range of minus 70 ° C plus 200 ° C, are not toxic, have chemical inertness with respect to structural materials, and have a low viscosity dependence temperature and high adhesion to contact surfaces. However, the known organosilicon compositions incorporate functional groups that lead to polymer crosslinking and the formation of solid compounds.

In optical instrumentation, the use of organosilicon materials is known. So in an invention protected by A.S. USSR No. 713892, IPC S08K 5/098, 1.980 for bonding optical elements, a composition based on low molecular weight siloxane rubber (grade SKTN) with a viscosity range from 2000 to 10000 mm ² / s is proposed.

The disadvantages of the known compositions include limited viability, deterioration of optical properties associated with crosslinking of siloxane chains.

A polydimethylsiloxane fluid with a viscosity of 20,000 mm ² / s at 20 ° C is described, which is used as an instrument and damping fluid, the main disadvantage of which is its leakage when trying to use in optical contact (Sobolevsky M.V., Muzovskaya O.A., Popeleva G . C. Properties and applications of organosilicon products. M, Chemistry, 1975. P.44).

Known sealing composition for optical instruments having good adhesion (Patent KR 20040035573, IPC C08L 83/00, 2004).

However, the known composition does not provide the mobility of glued work surfaces, which is its main disadvantage.

In 2011, a silicone grease was patented (Patent JP 2011084698, IPC C10M 107/50), consisting of dimethylsiloxane fluid and thickeners.

Silicone grease does not provide the required optical performance.

The scientific literature describes VNIINP-299 grease, which is a dense, sticky, gray ointment. Such a lubricant is prepared from high viscosity polymethylsiloxane fluid and silica gel. The grease is intended for use in the mechanisms of panning devices for photo and film equipment. (Fuels, lubricants, technical fluids. Assortment and application: Handbook / I.G. Anisimov et al. Edited by V. M. Shkolnikov. M., Publishing Center “Tekhinform.” 1999. P 330-332).

The disadvantage of this lubricant is the low refractive index of less than 1.4100 and performance in a narrow temperature range.

Closest to the proposed composition and adopted as a prototype is sealing paste for the prevention and elimination of leaks in pipeline valves (RF Patent No. 2218384, IPC С10М 169/06, 12/10/2003), containing oligoorganosiloxanes (polymethylsiloxanes or polymethylphenylsiloxanes) with a viscosity of 10,000 to 300,000 cps, and the thickeners and fillers contain a mixture of bentonite, chemically precipitated chalk, white carbon black, fluoroplast, aerosil, mica, high molecular weight and low molecular weight rubbers.

A significant disadvantage of the known paste is that it is opaque, dark brown in color and stable in the temperature range from minus 60 ° C to plus 80 ° C.

The objective of the invention is to develop an organosilicon composition for connecting and sealing optical elements, with maximum light transmission, without changing the optical properties of the connected parts, with a refractive index of from 1.4100 to 1.4300, operable in a wide temperature range of minus 70 ° C plus 300 ° C , non-toxic, chemically inert to structural materials, as well as with a low temperature dependence of viscosity and high adhesion to contact surfaces.

As a result of the analysis of patent documentation, scientific literature and research as an organosilicon composition for connecting and sealing optical elements based on a plastic base and a thickener, a composition is proposed consisting of a base - a mixture of polydimethylsiloxane and polymethylphenylsiloxane liquid with a viscosity of 3000 to 40,000 mm ² / s at a temperature of 20 ° C and a thickener of silicon dioxide, the composition has a refractive index of 1.4100-1.4300 and a penetration value of 160-280 units, and it works is in the temperature range minus 70 ° C plus 300 ° C, the following composition, wt.%:

Base (mixture of polydimethylsiloxane and polymethylphenylsiloxane liquid) 90-96 Thickener - Silica 10-4

The base of the organosilicon composition is a mixture of polymethylsiloxane liquid (PMS), of the general formula: (CH ₃ ) ₃ SiO [(CH ₃ ) ₂ SiO] _n Si (CH ₃ ) ₃ , with a viscosity of 1000 to 50,000 mm ² / s and polymethylphenylsiloxane liquid (PFMS), of the general formula:

(CH ₃ ) ₃ SiO [(CH ₃ ) ₂ SiO] _k [CH ₃ (C ₆ H ₅ ) SiO] _m Si (CH ₃ ) ₃ ,

where k / m = 10/1, with a viscosity of 10,000 to 20,000 mm ² / s g in the ratio of PMS-60-40%, PFMS - 40-60%.

Examples illustrate the present invention.

Example 1

270 g of polydimethylsiloxane liquid (PMS) with a viscosity of 1000 mm ² / s and 180 g of polymethylphenylsiloxane liquid (PFMS) with a viscosity of 10,000 mm ² / s are loaded into a container equipped with a heater, a stirrer and a thermometer, the contents of the container are mixed and 450 g of the mixture are obtained with a viscosity of 3000 mm ² / s, which is the basis of the composition (table 1), then add 50 g of silicon dioxide powder, the mass is heated to a temperature of 40-60 ° C and stirred for 3-4 hours. After that, the resulting mass is cooled to room temperature, unloaded and analyzed according to quality indicators (table 2).

1. Appearance - colorless transparent ointment-like plastic mass

2. Penetration at 20 ° C - 160 units

) при 20°C - 1,41003. The refractive index (

) at 20 ° C - 1.4100

4. Frost resistance (pour point), ° C - minus 70

5. Thermal stability,% weight loss at 300 ° C for 2

hours - 0.5

Analogously to example 1 prepare the silicone composition in examples 2-9, the composition of which is given in table 2.

The proposed organosilicon composition obtained in examples 1-9 is non-toxic, has a chemical inertness with respect to structural materials, has a low viscosity dependence on temperature and high adhesion to contact surfaces.

The high viscosity of the base composition (3000-40000 mm ² / s) and a small change in its value with temperature ensures the normal operation of optical instruments, smooth running and clear fixation of moving parts in winter and summer. The penetration value at 20 ° C (characteristic of the lubricating composition) in the range from 160 to 280 units. The organosilicon composition is characterized by high stability in the temperature range of minus 70 plus 300 ° C, weight loss at a temperature of 300 ° C for 2 hours no more than 1%, while maintaining the plastic properties of the lubricant. When used as an optical contact in devices, it does not lose its optical properties (transparency) over time, the stability of refractive index values from 1.4100 to 1.4300 and elasticity.

Claims (1)

Organosilicon composition for connecting and sealing optical elements based on a plastic base and thickener, characterized in that the composition contains a mixture of polydimethylsiloxane (PMS) and polymethylphenylsiloxane (PFMS) liquid with a viscosity of 3000 to 40,000 mm ² / s at a temperature of 20 ° C as a plastic base in the ratio of PMS - 60-40%, PFMS - 40-60%, as a thickener - silicon dioxide, while the composition has a refractive index of 1.4100-1.4300, the penetration value of 160-280 units, and it works in the temperature range mine . 70 ° C plus 300 ° C, at the following component ratio, wt%:
Basis - a mixture of polydimethylsiloxane and polymethylphenylsiloxane fluid 90-96 Silica 10-4