JPH02255690A - Alpha,omega-bis(alkylethynylaryloylamide)oligosiloxane and heat resistant hot melt adhesive - Google Patents

Abstract

NEW MATERIAL:A compound expressed by formula I [R1 and R2 are monovalent hydrocarbons containing (substituted) aromatic rings; R3 and R4 are bivalent hydrocarbons containing (substituted) aromatic rings; R5 is monovalent hydrocarbon containing H or (substituted) aromatic ring; n is 1-10]. EXAMPLE:A compound expressed by formula II. USE:A heat resistant hot melt adhesive useful for sealing agent for electric circuit being stable, having excellent adhesive strength and meltable in adhesive temperature without volatilizing. PREPARATION:Chlorosilane expressed by the formula YmSiX4-m (Y is R1 or R2; X is halogen; m is 2) is reacted with an organic base and then the resultant aminosilane is reacted with an amino alcohol expressed by the formula NH2R3 OH to afford an alkoxysilane having amino groups at both ends. Then the compound is reacted with an acid chloride expressed by the formula XR4COCl to give an intermediate expressed by formula III, which is reacted with a compound expressed by the formula R5CidenticalCH using a Pd catalyst.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a novel substance useful as a hermetic sealant for highly airtight bonding and electronic components, and a heat-resistant melt adhesive containing the same.

[Conventional technology]

Spot welding is often used to join aluminum and titanium used in the aerospace industry to ensure safety. However, it is difficult to perform a joint that requires airtightness only by welding, and it is disadvantageous in that it requires a lot of cost. In particular, when the shape is complex like a honeycomb structure, advanced technology is required to ensure airtightness only by welding. Therefore, there has been a need for materials and heat-resistant adhesives that can be used alone or in combination with welding to ensure airtightness. Heat-resistant adhesives melt at the desired bonding temperature and do not volatilize; cross-linking occurs at a temperature that is an appropriate temperature difference higher than the melting temperature; the molecular structure is stable and heat resistant; It is necessary to satisfy three conditions of having the necessary polarity. Furthermore, in the field of electronic equipment, there is a demand for adhesives having heat resistance that can sufficiently withstand hermetic sealing temperatures as non-conductive hermetic sealants used in electronic circuits. As a heat-resistant adhesive, for example, JP-A-58-74
Various polyimide-silicone precursors are disclosed in Japanese Patent Publication No. 73 and Japanese Patent Application Laid-Open No. 61-62525. These utilize the condensation of a polyamide structure into a polyimide structure upon heating for adhesion. This reaction is expressed as follows. (Left below) (Ar is a tetravalent organic group, R is a divalent hydrocarbon group, and Ro is a monovalent hydrocarbon group) However, in this reaction, a condensation reaction occurs with heating and water is eliminated. It has the disadvantage of weak adhesive strength. For this reason, methods are used to improve the adhesive strength using a primer or to add a primer to the polyamic acid precursor. These adhesives have a siloxane structure represented by the raw material diamine (R is a divalent hydrocarbon group, Ro is a monovalent hydrocarbon group), and the divalent hydrocarbon group R is an amino group and It is bonded to a silyl group. Generally Si
Since atoms have a stronger affinity with oxygen atoms than with carbon atoms, such structures have problems in heat resistance at high temperatures. In addition to the above, heat curing of maleimide-type compounds at both ends is used as a melt adhesive that does not produce volatile substances as by-products. Although it has been proposed, it is not always satisfactory. In addition, because the surface of highly heat-resistant resins made of polyamides such as Kevlar is inert, sufficient adhesive strength cannot be obtained even with known adhesives such as urethane-based adhesives, and they are easily peeled off. There was a drawback that

[Problem to be solved by the invention]

The present invention was made to solve the above-mentioned problems, and it only melts at a desired bonding temperature without volatilization, but hardens at a specific temperature higher than the melting temperature, has heat resistance, and has high bonding strength. Aims to provide high compound and heat resistant adhesives.

[Means to solve the problem]

As a result of extensive research aimed at developing adhesives suitable for the various uses mentioned above, the present inventors have found that compounds having siloxane units, amide units, and alkynyl units in the molecule are excellent as heat-resistant melt adhesives. They discovered this and completed the present invention. That is, the novel substance of the present invention, which has been made to achieve the above object, is an α,ω-bis(alkylethynylaryloylamide) oligosiloxane represented by the general formula. Further, the heat-resistant melt adhesive of the present invention is composed of a compound having α,ω-bis(alkylethynylaryloylamide)oligosiloxane represented by the above general formula in one molecule. In the formula, R1 and R2 are the same or different monovalent hydrocarbon groups containing a substituted or unsubstituted aromatic ring, such as a methyl group. R3 and R4 are the same or different divalent hydrocarbon groups and contain substituted or unsubstituted aromatic rings. For example, phenylene group. R5 is a hydrogen atom or a monovalent hydrocarbon group of the same type, and contains a substituted or unsubstituted aromatic ring. This monovalent hydrocarbon group is, for example, a phenyl group. The number n of siloxane units is an integer from 1 to 1O. For the production of the new material of the present invention, Y @ S I X a , which is produced in large quantities in the silicon industry, is used as a starting material.
-m (Y is a monovalent hydrocarbon group corresponding to R1, R2, contains a substituted or unsubstituted aromatic ring, X is a halogen atom, m=2 or 3) is used. - When m=2 for chlorosilane yastx4-@ Chlorsilane Y*5zXx is dissolved in a non-alcoholic solvent containing no water, and an organic salt such as triethylamine is reacted with the solution to produce aminosilane. Then amino alcohol NH,-
When the organic salt is removed from the reaction with R3-OH, an alkoxysilane having amino groups at both ends is obtained. Then, acid chloride X-R4-COCl is added to this amino group.
By reacting in a non-aqueous solvent, an amide bond is generated, and an intermediate [I] of the following formula is obtained. When intermediate [I] is reacted with R5CICH using a palladium catalyst and subjected to HX removal, an alkynyl group is introduced and the target compound Q2 having a siloxane unit, an amide unit, and an alkynyl unit is obtained. In the above reaction, dichlorosilane was used as the starting material, so the obtained oligomer contained only one siloxane unit. , multiple siloxane units can be introduced into its molecular structure.・Chlorsilane Y m S t X 4-s is m=3
In this case, the chlorosilane YsSiX used as a starting material is reacted with an organic salt to form an aminosilane as in the case of m=2, and then reacted with an aminoalcohol to remove the organic salt to obtain an aminophenoxysilane having an amine group at only one end. By reacting the amino group of the obtained aminophenoxysilane with acid chloride, X-R4-COCl in a non-aqueous solvent, an amide bond is generated, and an intermediate [III
is obtained. Former Lt After reacting this intermediate [III with R6CmCH (R6 is a trimethylsilyl group) using the palladium catalyst described above, when this reaction solution is treated with an alkaline alcohol solution, an intermediate containing no silyl group [■■ ] IC roof C
-R4C0NH-R3-OH is obtained. This intermediate'
When twice the mole of [III] is reacted with dichloropolysiloxane having C1 at both ends, the terminal R5 is hydrogen,
An oligomer having siloxane units, amide units and alkynyl units is obtained. In addition, even in the case of m=2.3, the maximum number of siloxane units is 1O, and if this value is exceeded, the proportion of amide bonds in the oligomer decreases, and the adhesive strength decreases.

[Effect]

The novel substance of the invention is used as a heat-resistant melt adhesive, for example, as follows. An adhesive solution dissolved in a solvent is applied to the surface of the cleaned member to be adhered, and heated to vaporize the solvent. Next, it is combined with the other member to be adhered, and the temperature is gradually raised to 100 to 500°C, preferably 200 to 400°C. Then, the oligomer contained in the adhesive melts at a temperature of 50°C or higher, and becomes 18°C.
Since the terminal acetylene group gradually undergoes a crosslinking reaction at 0° C. or higher, the alkynyl group becomes three-dimensional and the adhesion is completed. In this way, the oligomer in the adhesive melts at the desired bonding temperature without volatilizing, and is crosslinked at a temperature higher than the melting temperature by an appropriate temperature difference. It has excellent heat resistance because it has a heat-resistant polyamide and siloxane structure. Furthermore, since it has an amide bond as a polar group, high adhesive strength can be obtained. Therefore, it satisfies the requirements for a heat-resistant adhesive. Note that, depending on the purpose, an inorganic filler such as silica, metal oxide, carbon black, red iron oxide may be mixed with this adhesive. Metal powder can also be added to impart electrical conductivity to the coating. It is also possible to improve heat resistance by adding it to other silicone adhesives. Further, it is optional to use a solvent during use.

【Example】

The present invention will be explained in detail below. Example 1 - Reaction using dichlorodimethylsilane as the starting material - Diethylamine 85.511j (0,826 mol) was dissolved in dry methylene chloride 5111al, -1
Cool to 0°C. Add 2 dichlorodimethylsilane to this solution.
0 ml (0,165 mol) is added dropwise and reacted. The by-product amine salt produced by the reaction was filtered, unreacted amine and solvent were removed, and then distilled to obtain bis(N,N-diethyl)aminodimethylsilane (boiling point 81-82°C/17+n
mHg). The obtained aminomethylsilane 15aI (0,0612
mol) is added dropwise to a solution of 16.35 g (0.15 mol) of aminophenol dissolved in dry benzene 1001 at 80° C. and stirred at the same temperature for 3 hours. After removing unreacted aminophenol by filtration, the solvent was evaporated, and bis(P-aminophenoxy)dimethylsilane (melting point 6) was purified by column chromatography using methylene chloride as a solvent.
4°C) was isolated. The yield was 42%. 1.64 g (59 moles of 0.0O) of the isolated bisCP-aminophenoxy)dimethylsilane was added to 20 g of dimethyl acetic acid.
+nL A solution dissolved in a mixed solution of 5 ml of triethylamine and a solution of 2.7 g (0,0123 mol) of P-bromobenzoic acid chloride dissolved in dimethyl acetic acid of 51 were reacted at room temperature, and after stirring for 2 hours, the solvent is removed under reduced pressure. When 40 mj of alcohol-free methylene chloride is gradually added to the residual liquid, white crystals are obtained. After filtering this white crystal, it was washed with 50 mg of chloroform to obtain an intermediate compound shown in formula [11]. The melting point of this compound was 246-253°C. Next, put dry dimethyl acetic acid 50-1 into a 100 ml 40 flask, and add compound 6 of formula [1] under a stream of dry nitrogen gas.
．． Add 4 g (10 mmol). To this is added triethylamine lO so 1 and ethynylbenzene 2.1 g (20
, 5 mmol), triphenylphosphine 43.2 mg (0,165 mmol) as a palladium catalyst, and copper iodide 21.6 mg (0,114 mmol).
Bis(triphenylphosphine)palladium(II) chloride 21.5B (0,031 mmol) is added. After heating these mixed solutions to 95° C. and reacting for 5 hours, triethylamine salts are removed by filtration. Add 300 esj of alcohol-free chloroform to the filtrate. When kept overnight at room temperature, 4.6 g of pale yellow powder separated out. This was redissolved in dimethyl acetic acid and reprecipitated with chloroform to obtain 2.2 g of the oligo shown in formula [2]. When the melting point and curing temperature of the obtained compound were measured, the melting point was 262 to 265°C, the curing temperature was 382°C, and the optimum curing temperature was 320°C. Differential thermal analysis (DSC)
The measured values at 1 and 2 also showed the same values. Further, when IR analysis was performed, absorption due to acetylene bond was observed at 2214 cm-'. Prepare a 5% dimethyl acetic acid solution of the obtained oligomer,
Coat it on a titanium test piece (20X 20X O, 5 μm) and heat it at 150℃ for 30 minutes and at 300℃ for 30 minutes in 5 layers 40
When a coating film was prepared by heat treatment at 0° C. for 10 minutes, the coating film was firmly adhered to the titanium piece. Example 2 - Reaction using trichloromethylsilane as the starting material - Dichlorodimethylsilane used as the starting material in Example 1
(CHs) Replaced with 5fC1t (CHshSiC
An intermediate compound represented by formula [3] was obtained in the same manner as in Example 1, except that 1 was used. 11 g (0-03 moles) of the compound of formula [3], 3.5 g (0,036 moles) of ethynyltrimethylsilane and 150 ml of triethylamine are dissolved in 150 a+j of dry benzene. In this solution, as a palladium catalyst, triphenylphosphine 86 mg s copper iodide 43 ag,
43 g of bis(triphenylphosphine)palladium(II) chloride was added, and the mixture was allowed to react overnight at 50° C. in a nitrogen gas stream, followed by the same treatment as in Example 1 to obtain a disilyl derivative as a viscous liquid. When this disilylamide derivative was heated in a methanol solution of CO3 (metathurisis reaction), N(P-hydroxyphenyl)P-ethynylbenzoic acid amide represented by the formula % was obtained in a yield of 97%. This compound exhibited no melting point and cured exothermically at 247°C. This compound is then reacted with dichlorodimethylsilane in dry benzene in the presence of trimethylamine to give [
4] The oligomer point (endothermic peak) of a yellow-white solid was shown, and exothermic curing (exothermic peak 210° C.) occurred immediately. The NMR analysis results show that the protons of the methyl groups corresponding to R1 and R2 are o, 37 ppm (intensity 6
H), the protons of the phenyl group corresponding to R3 and R4 are 6.94 to 7.96 ppm (intensity 16H, multi-peak), the proton of the amide group is 4.39 (2 old, the terminal proton is 10.26 (2H)) A 5% dimethyl acetic acid solution of this oligomer was prepared, coated on a silicon substrate, and heat treated at 150°C for 30 minutes, 200°C for 30 minutes, and 300°C for 20 minutes. It adhered strongly to the substrate and did not peel off easily. Example 3 The same molar amount was obtained in place of the starting material in Example 2. The yield was 93%. Thermal analysis revealed that the reaction was carried out in the same manner as in Example 2, except that the temperature was 202°C and the solvent was changed to tetrahydrofuran. After the reaction, triethyl hydrochloride was filtered off, and the solvent tetrahydrofuran was removed under reduced pressure. A white solid was obtained with a yield of 98%. This solid was dissolved in benzene, insoluble materials were filtered out, hexane was added, and the mixture was allowed to stand for a long time to re-precipitate, resulting in a silk-like fine needle-like substance. A crystal was obtained. The melting point of this crystal by DSC was 75°C (endothermic peak)
Then, heat generation gradually started from about 185°C, and the curing reaction progressed (exothermic peak: 216°C). After a tetrafuran solution of this substance was applied to two steel plates and the solvent was evaporated, the coated surfaces were pressed and heated to 220°C, and good adhesion of the steel plates was observed. In addition, when this substance was melted and hardened on a glass plate and observed,
The cured material was red, transparent, and glassy.

【Effect of the invention】

As explained in detail above, the compound of the present invention has a heat-resistant polyamide and siloxane structure, so it has high heat resistance (stable). Also, since it has an amide bond as a polar group, it has adhesive strength. is high.When using,
At the desired bonding temperature, it only melts and does not volatilize, and can be crosslinked and cured at a temperature higher than the melting temperature by an appropriate temperature difference. Therefore, the compound of the present invention or an adhesive containing the compound can be used as a bonding adhesive that requires airtightness, for sealing a honeycomb structure that requires heat resistance, as an airtight sealant for electronic circuits, or as a surface protective film for electronic circuits. It is useful as an insulating film.

Claims (1)

[Claims] 1. General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (R1 and R2 are the same or different monovalent hydrocarbon groups,
It contains a substituted or unsubstituted aromatic ring, R3 and R4 are the same or different divalent hydrocarbon groups and contain a substituted or unsubstituted aromatic ring, and R5 is a hydrogen atom or the same kind of monovalent hydrocarbon group. an α,ω-bis(alkylethynylaryloylamide) oligosiloxane represented by a group containing a substituted or unsubstituted aromatic ring, n being an integer of 1 to 10. 2. The α,ω-bis(alkylethynylaryloylamide) oligo according to claim 1, wherein R1 and R2 are methyl groups, R3 and R4 are phenylene groups, and R5 is phenyl group. Siloxane. 3. The α,ω-bis(alkylethynylaryloylamide) oligo according to claim 1, wherein R1 and R2 are methyl groups, R3 and R4 are phenylene groups, and R5 is a hydrogen atom. Siloxane. 4. There are general formulas ▲ mathematical formulas, chemical formulas, tables, etc. in one molecule ▼ (R1 and R2 are the same or different monovalent hydrocarbon groups,
It contains a substituted or unsubstituted aromatic ring, R3 and R4 are the same or different divalent hydrocarbon groups and contain a substituted or unsubstituted aromatic ring, and R5 is a hydrogen atom or the same kind of monovalent hydrocarbon group. A heat-resistant compound comprising an α,ω-bis(alkylethynylaryloylamide)oligosiloxane represented by a group containing a substituted or unsubstituted aromatic ring, where n is an integer of 1 to 10. adhesive. 5. The heat-resistant melt adhesive according to claim 4, wherein R1 and R2 are methyl groups, R3 and R4 are phenylene groups, and R5 is phenyl group. 6. The heat-resistant melt adhesive according to claim 4, wherein R1 and R2 are methyl groups, R3 and R4 are phenylene groups, and R5 is a hydrogen atom.