RU2034890C1 - High-temperature adhesive material for joining of structural materials - Google Patents

Abstract

FIELD: glue compositions. SUBSTANCE: adhesive material has polycarbosilane of the general formula

(I) or

(II) where y = 10-60; R, R,R′-H, Alk, Ar, Vin - H, Alk, Ar, Vin; n = 1-20; m = 0; x = 2-50, with molecular mass 400 (not less), and polysilasane of the general formula

(III) where R, R, R′, R″ - H, Alk, Ph, Vin, Cl; a, b, c = 0-3; z = 3-10, with molecular mass 900 (not less), or

Description

 The invention relates to adhesive compositions based on organosilicon polymers and can be used to connect any heterogeneous structural materials, in particular ceramic materials based on nitrides, carbides or oxides, composite materials (carbon plastics, fiberglass, etc.) with metals and alloys, and can find application in mechanical engineering, aerospace and cryogenic engineering, electrical engineering and other industries for the manufacture of integral parts and structures working in high and low temperatures in oxidizing environments and at increased mechanical loads.

Known high-temperature adhesive based on polycarboransiloxanes, cured at 315 ^about C and a pressure of 0.15 MPa [1]
The disadvantage of the adhesive is relatively low thermostability (500-600 ° ^C) and under high bonding strength in shear (22.5 MPa).

где R Н или углеводородный радикал;
0,5 ≅a≅ 1,9;
0 ≅b≅ 0,7;
a + b ≅ 1,9, 10-80 ч невулканизированного акрилового каучука, 1-60 ч алкоксисилана формулы
R'cSi(OR'')_4-c где R' H или AlK;
R'' углеводородный радикал;
с 0-3 [2]
Недостатком адгезива является недостаточная прочность соединения материалов при повышенных температурах, низкая термостойкость (не выше 500^оС), что сужает область его применения.Known high temperature adhesive for connecting structural materials containing 100 hours of polyorganosiloxane of the General formula
Ph _a R _b SiO

where R H or a hydrocarbon radical;
0.5 ≅a≅ 1.9;
0 ≅b≅ 0.7;
a + b ≅ 1.9, 10-80 hours of unvulcanized acrylic rubber, 1-60 hours of alkoxysilane of the formula
R'cSi (OR '') _4-c wherein R'H or AlK;
R "is a hydrocarbon radical;
from 0-3 [2]
A drawback of adhesive bond strength is insufficient material at elevated temperatures, low heat resistance (not higher than 500 ° ^C), which narrows the field of its application.

The closest technical solution to the proposed is a high-temperature adhesive containing triorganosiloxane, polydiorganosiloxane, an organosilicon compound and a curing initiator [3]
The disadvantage of the adhesive is relatively low heat resistance ^(about 700-800 C) and is not sufficiently high strength of the adhesive joint.

The aim of the invention is the creation of a high-temperature adhesive for bonding dissimilar structural materials (ceramic and composite materials with metals and alloys) with high strength and the ability to withstand temperature changes in a wide range (from -196 to 1500 ^about C).

The goal is achieved in that the high-temperature adhesive contains a mixture of organosilicon polymers from the class of polycarbosilanes (PCS) and polysilazanes (PSZ), organic peroxide (dicumyl peroxide, lauryl peroxide, tert-butyl) and a powder filler selected from a number of joined materials and high-temperature carbides, , oxides, in the following ratio of components, wt. Polycarbosilane 5-20 Polysilazane 5-20 Organic peroxide 0.5-3 Powder filler Remaining As a powder filler, the adhesive contains powder from a number of structural materials to be joined, as well as at least one compound from a series of nitrides Si ₃ N ₄ , BN, AlN, FiN, carbides SiC, B ₄ C, TiC; oxides SiO ₂ , Al ₂ O ₃ , TiO ₂ , ZrO ₂ , Y ₂ O ₃ .

 As an initiator of curing, the adhesive contains dicumyl, tertiary butyl or lauryl peroxide.

As polycarboxylans, compounds of the general formulas [(Me ₂ SiCH ₂ ) _n (RR ^' Si) _m ] _x (I) can be used
or [MeHSiCH ₂ ] _y (II)
PKS-1 PKS-2 where R, R ^' H, AlK, Ar, Vin; n 1-20; m 0.1; x 2-50; y 10-60; with a mol.m. not less than 400.

PRI me R 1 (receiving the product PKS-1). 29.1 g (1.2 moles) of magnesium, 250 ml of absolute THF, 5.5 g (0.03 moles) of dibromatane are charged into a 1-necked 1-liter flask equipped with a stirrer, a dropping funnel with a bypass, a reflux condenser and a thermometer. 0.5 g (0.004 mol) of cobalt chloride. The mixture was heated with stirring at a temperature of the reaction mass of 65 ^{° C} from a dropping funnel, a solution of 94.4 g (0.66 mol) hlormetildimetilhlorsilana in 50 ml THF. Then thereto was added 46.5 (0.38 mole) metilvinildihlorsilana stirred for 10 hours at 80 ^° C from the reaction mixture 69.2 g product was isolated PKC-1 having a molecular weight 700.

PRI me R 2 (obtaining the product PKS-2). Four-necked flask of 0.5 liter capacity equipped with a stirrer, a reflux condenser, an argon inlet tube and a thermometer was charged with 100 g of polydimethylsilane (PDMS), heated to 360 ^C and kept at this temperature for 10 hours. The reaction mixture was subjected to vacuum distillation (280 ^about C / 1-2 mm Hg) and get 70 g of the product PKS-2 with the number average mol.m. 400.

PRI me R 3 (obtaining the product PKS-2). In a 2-liter autoclave was charged with 250 g of PDMS was heated to 470 ° ^C under pressure of 70 atm for 14 hours under a nitrogen atmosphere. The reaction mass is cooled to room temperature and 100 ml of n-hexane are added. The reaction mixture was filtered, the filtrate was evaporated at atmospheric pressure and then at 280 ^{° C} / 1-2 mmHg Get 70 g of the target product PKS-2 with mol.m. 1500.

[RSi(NH)_1,5]_a[R′R″SiNH]_b[Me₃SiNH]

(III)
ПСЗ-1 где R,R^',R^'' H, AlK, Ph, Vin, Cl; (a,b,c 0-3; z 3-10 с мол.м. не менее 900. Полисилазаны ПСЗ-1 могут быть использованы в виде растворов в органическом растворителе (толуол, ксилол, бензин и т.п.) с содержанием сухого остатка не менее 80%
П р и м е р 4 (получение продукта ПСЗ-1). Смесь 38,7 г (0,3 моля) диметилдихлорсилана, 145,4 г (0,9 моля) винилтрихлорсилана, 266,3 г (1,65 моля) гексаметилдисилазана и 250 мл толуола загружают в куб ректификационной колонки, нагревают до кипения и за 6 ч при температуре в кубе 80-125^оС отгоняют выделявшийся триметилхлорсилан. Реакционную смесь упаривают на роторном испарителе в вакууме 1˙10 мм рт.ст. и получают 73,8 г продукта ПСЗ-1 с мол.м. 1345 и содержанием сухого остатка 81,5%
В качестве полисилазанов могут быть использованы соединения общей формулы

[Me₂SiCH₂]_d[MeSiCH₂CH₂]_g[Si(NH)_1,5]_h[MeR′′′SiNH]

(IV)
ПСЗ-2 где R^''' AlK, Ph;
d 1-20;
g 0-5;
h,q 0-3;
w 2-20, с мол.м. не менее 1500
П р и м е р 5 (получение продукта ПСЗ-3). В четырехгорлую колбу емкостью 0,25 л, снабженную мешалкой, термометром, головкой от ректификационной колонки и трубкой для подачи инертного газа, загружают 50,0 г поликарбосилана ПКС-1 (мол.м. 700) и 78,8 г полисилазана ПСЗ-1 мол.м. 1040. К смеси при перемешивании добавляют 0,53 г (0,5 мас.) бис-(диметилсилил) амида натрия, подают инертный газ и нагревают до 110-120^оС. Реакционную смесь перемешивают при этой температуре в течение 3 ч, отгоняя легколетучие. После отгонки легколетучих температуру реакционной массы повышают до 140^оС, перемешивают 2 ч, охлаждают до 70-80^оС. Получают 108,0 г полисилазана ПСЗ-2 с мол.м. 2640.As polysilazanes, compounds of the general formula can be used

[RSi (NH) _1.5 ] _a [R′R ″ SiNH] _b [Me ₃ SiNH]

(III)
PSZ-1 where R, R ^' , R ^'' H, AlK, Ph, Vin, Cl; (a, b, c 0-3; z 3-10 with mol.m. not less than 900. Polysilazanes PSZ-1 can be used as solutions in an organic solvent (toluene, xylene, gasoline, etc.) with the content dry residue not less than 80%
PRI me R 4 (obtaining the product PSZ-1). A mixture of 38.7 g (0.3 mol) of dimethyldichlorosilane, 145.4 g (0.9 mol) of vinyl trichlorosilane, 266.3 g (1.65 mol) of hexamethyldisilazane and 250 ml of toluene is loaded into a distillation column cube, heated to boiling and for 6 hours at a temperature of 80-125 in a cube ^about trimethylchlorosilane distilled off was isolated. The reaction mixture is evaporated on a rotary evaporator in a vacuum of 1˙10 mm Hg. and get 73.8 g of product PSZ-1 with mol.m. 1345 and a solids content of 81.5%
As polysilazanes, compounds of the general formula can be used

[Me ₂ SiCH ₂ ] _d [MeSiCH ₂ CH ₂ ] _g [Si (NH) _1.5 ] _h [MeR ′ ′ ′ SiNH]

(Iv)
PSZ-2 where R ^''' AlK, Ph;
d 1-20;
g 0-5;
h, q 0-3;
w 2-20, with a mol.m. not less than 1500
PRI me R 5 (obtaining the product PSZ-3). In a four-necked 0.25-liter flask equipped with a stirrer, a thermometer, a distillation column head and an inert gas supply tube, 50.0 g of PKS-1 polycarbosilane (mol. 700) and 78.8 g of PSZ-1 polysilazane are charged mol.m. 1040. To the mixture under stirring was added 0.53 g (0.5 wt.) Of bis (dimethylsilyl) amide, the inert gas and heated to 110-120 ^C. The reaction mixture was stirred at this temperature for 3 hours while distilling off volatile. After distilling off the volatile reaction mass temperature increased to 140 ^{° C,} stirred for 2 hours, cooled to 70-80 ° ^C to give 108.0 g of polysilazane COR-2 having a molecular weight 2640.

 Preparation of high temperature adhesive is as follows.

 In a metal glass with a capacity of 0.5 l, equipped with a jacket with coolant and a paddle mixer, 5-20 wt. polycarbosilane PSK-1 (or PKS-2) mol.m. not less than 400, 5-20 wt. polysilazane PSZ-1 mol.m. not less than 900 (or PSZ-2 mol.m. not less than 1500) and 0.4-3.0 wt. dicumyl peroxide (or tert.-butyl, lauryl), stirred for 15-20 minutes. After that, up to 100 wt.% Are added portionwise to the organosilicon component of the adhesive for 1 h with constant stirring powder filler with particle sizes up to 50 microns. Homogenization of the adhesive composition is carried out using a ball mill (stirring speed 1000 rpm, time 4 hours).

 The resulting adhesive is subsequently used to connect structural materials.

 PRI me R 6. Connection plates SiC / steel 15X28.

The surface of the plates (100x10x10 mm) of silicon carbide is treated with detergent, alcohol and dried. The surface of the plates made of steel grade 15X28 (100x10x2.5 mm) is subjected to sandblasting, treated with detergent and dried. Apply on the connected surfaces with a brush an adhesive containing, by weight. Polycarbosilane PKS-1 (mol.m. 700) 10.0 Polysilazane PSZ-1 (mol.m. 1260) 15.0 Dicumyl peroxide 1.0
The particulate filler: Applies a steel plate 37.0 15H28 overlap (10 mm), secured by mechanical clamps and then placed in an oven and maintained at 200 ^{° C} for 1.5 hours in air. The temperature was then raised to ¹¹⁰⁰ C and kept at this temperature under argon for 0.5 hours. After cooling plates conducted strength test compound (glue line) by standard methods. Shear Strength compound was 350 MPa (at ²⁰ ° C).

The results of Example 6 and other examples of the use of adhesive for connecting different types of ceramic and composite materials are shown in Table indicating composition and the adhesive strength in shear of the obtained compounds (at ²⁰ ° C) after exposure joined materials at different temperatures.

 High results were obtained when connecting various plates: oxide ceramic / alloys, oxide-free ceramic / alloys, fiberglass / alloy / carbon fiber, etc.

As follows from the data presented, the invention provides a ceramic adhesive bonds and composite materials with metals and alloys are characterized by high mehanoprochnostnymi characteristics (shear strength at 20 C ^of 85-470 MPa), at temperatures ranging from -195 ^{° C} (liquid nitrogen ) to 1500 ^about C.

 Moreover, as can be seen from the table, the strength characteristics of the adhesive joint increase after heat treatment of the cured adhesive and subsequently change slightly after exposure to the obtained heat treatment temperatures and the exposure time is determined by the fracture temperature of composite materials, the softening temperature of metals and alloys, and also the temperature at which crystallization processes begin in ceramic materials. The latter is due to the fact that as a result of the process of thermal decomposition of polycarbosilanes and polysilazanes, a heterogeneous mixture of silicon carbide and silicon nitride with an admixture of free carbon and silicon is formed.

 The high mechanical strength characteristics of adhesive joints of structural materials are also explained by the fact that during the thermal destruction of the adhesive composition diffusion penetration of the elements of the intercontact layer through the surface of the substrates occurs, and in the case of porous materials this phenomenon is enhanced due to the physical penetration of the adhesive into the pores.

 The proposed high-temperature adhesive for joining structural materials can be used in almost any field of science and technology.

Claims (1)

HIGH TEMPERATURE ADHESIVE FOR CONNECTING CONSTRUCTION MATERIALS, comprising an organosilicon polymer and a curing initiator, characterized in that the adhesive further comprises a powder filler selected from the group consisting of aluminum, silicon, boron, titanium, titanium carbides, silicon, boron, titanium carbides, titanium carbides, titanium carbides aluminum, yttrium, zirconium or carbon, as an organosilicon polymer, the adhesive contains a polymer of the general formula

where R, R ₁ H, Alk, Ar, Vin;
n 1 20;
m 0.1;
x 2 50

where y 10 60,
with a mol.m. no less than 400
and polysilazane of the general formula

where R, R ', R''H, Alk, Ph, Vin, Cl;
a, b, c 0 3;
z 3 10,
with a mol.m. not less than 900 or

where R '''Alk,Ph;
d 1 20;
g 0 5;
h, q 0 3;
w 2 20,
with a pier. m. not less than 1500, and as the initiator of curing, peroxide of dicumyl, or benzene, or tert-butyl, or lauryl in the following ratio of components, wt. Polycarboxylan 5.0 20.0
Polysilazane 5.0 20.0
Hardener 0.5 3.0
Powder filler Else

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