JP2009292970A - Hybrid composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hybrid composition capable of smoothly carrying out a curing reaction, and evaporating no unreacted or low-molecular siloxane or affording an extremely trace amount of evaporation. <P>SOLUTION: The hybrid composition without containing the low-molecular siloxane is provided from a hybrid composition obtained by carrying out a hydrolytic reaction and a condensation reaction of a mixture having a silicate compound, and a polydimethylsiloxane having the silicate-modified terminal. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a hybrid composition that can be used as a heat-resistant elastic material or the like.

  2. Description of the Related Art Conventionally, heat-resistant adhesive materials and heat-conductive materials have been used for films, tapes, and the like for insulating or fixing electronic parts and electric parts that require heat resistance. A typical example is silicone rubber.

  This silicone rubber has heat resistance, is inexpensive and has high safety, and is generally well known as an elastic material. In recent years, hybrid compositions of silicone rubber with improved properties of this silicone rubber have been developed.

  Here, a hybrid composition is obtained by chemically reacting an inorganic component and an organic component at the molecular level, and has attracted attention as a new composition that combines the characteristics of an inorganic component and an organic component. (For example, refer nonpatent literature 1). This hybrid composition is considered to have both heat resistance due to inorganic components and flexibility due to organic components, for example, and is also promising as an elastomer having heat resistance.

  In the hybrid composition, a metal alkoxide, which is an inorganic component, and a silicic acid polymer, which is a polymer component that imparts elastic properties of an organic component, are subjected to a hydrolysis reaction (also referred to as “hydrolysis”) and a condensation reaction (also referred to as “hydrolysis”). This product is chemically bonded by "dehydration condensation reaction" or "dehydration polycondensation reaction.) High heat resistance and flexibility at 200 ° C or higher, high electrical insulation and low dielectric constant at high frequency (See Patent Documents 1 to 3).

Japanese Patent Laid-Open No. 1-113429 JP-A-2-182728 JP-A-4-227731 G. Philipp and Schmidt, J.A. Non-Cryst. Solids 63, 283 (1984)

  However, a small amount of low molecular siloxane remains in the silicone rubber described in Patent Documents 1 to 3 and the hybrid material described in Non-Patent Document 1, but the low molecular siloxane volatilizes and becomes cyclic. Since siloxane is generated, the following problems occur. In other words, in the electrical and electronic fields that use silicone rubber, this cyclic siloxane adheres to the surface of electrical contacts such as terminals, and becomes an insulating film, resulting in contact failure, causing problems such as poor conduction and malfunction. is doing.

  In order to solve such a problem, for the purpose of preventing the low molecular siloxane from remaining (residual) in the silicone rubber, the low molecular siloxane is volatilized in advance by heating at a high temperature during the production of the silicone rubber.

  However, when silicone rubber is heated at a high temperature and low molecular siloxane is volatilized during the production of silicone rubber, there are new problems that the odor of cyclic siloxane deteriorates the working environment and the flexibility of silicone rubber is impaired. appear.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a hybrid composition in which the amount of low-molecular siloxane remaining is extremely small or not contained at all. Such a hybrid composition can be used, for example, as a heat-resistant adhesive material or a heat conductive material.

[First invention]
The present invention relates to a hybrid composition obtained by subjecting a silicate compound and polydimethylsiloxane having a terminal silicate-modified to a hydrolysis reaction and a condensation reaction.
Hereinafter, polydimethylsiloxane is abbreviated as “PDMS”, and polydimethylsiloxane whose terminal is silicate-modified is abbreviated as “modified PDMS”.

(Silicate compound)
The silicate compound of the present invention is an oligomer of a metal alkoxide made of silicon (Si), having a siloxane (-Si-O-Si-) skeleton in the main chain and introducing an alkoxy group (RO) in the outer chain. It is a compound. Here, (R) which is the alkyl part of the alkoxy group (RO) is exemplified by a methyl group, an ethyl group, a propyl group, and the like. This silicate compound has the property of easily reacting with water.

  Since the silicate compound is an oligomer of a metal alkoxide, it has a higher molecular weight than the metal alkoxide, and is therefore less likely to volatilize. For this reason, when the silicate compound is hydrolyzed, volatilization of the low-molecular siloxane having high volatility contained in the modified PDMS can be further suppressed. Moreover, the silicate compound has high chemical reactivity, and can smoothly advance the condensation reaction.

  Examples of the silicate compound used in the present invention include methyl silicate, ethyl silicate, propyl silicate and the like. Ethyl silicate is preferred from the standpoints of quality stability and safety. In the case of using methyl silicate for the purpose of increasing the reactivity, it is necessary to reliably carry out the treatment of volatile methanol.

(Modified PDMS)
The modified PDMS of the present invention is obtained by modifying the end of PDMS with a silicate compound, PDMS having silanol groups at both ends, and an alkoxy group that is a hydrolyzable functional group on one or both sides of the main chain. What is obtained by making it react with the alkoxysilane partial condensate which has this.

  This modified PDMS has a much higher functional group concentration than ordinary PDMS. Further, since the modified PDMS has high condensation reactivity with the silicate compound, the alkoxysilane partial condensate contained in the modified PDMS can be smoothly polymerized by being subjected to a condensation reaction smoothly.

  As the modified PDMS used in the present invention, those having a mass average molecular weight in the range of 5000 to 100,000 are used.

(Hydrolysis reaction and condensation reaction)
In the present invention, a mixture having the above-described silicate compound and the above-described modified PDMS is subjected to hydrolysis and condensation reaction.

Since the silicate compound is easily hydrolyzed in the presence of water, the alkoxy group in the molecule of the silicate compound becomes a highly reactive silanol group (—OH group).
On the other hand, the modified PDMS is also hydrolyzed to form a silanol group (also referred to as “silanol modification”) due to the presence of water.

  Since both of these silanol groups have high reactivity and at the same time have similar reactivity, aggregation of silanol is caused by hydrolyzing the mixture containing the silicate compound and the modified PDMS. The condensation reaction with the modified PDMS proceeds smoothly without being accelerated. Thereby, the low molecular siloxane contained in the modified PDMS is also taken into the reaction product (hybrid composition).

  That is, the low molecular weight siloxane becomes a part of the material constituting the hybrid composition by the hydrolysis reaction and the condensation reaction, and does not exist as a simple substance, or the amount existing as a simple substance becomes very small. For this reason, the low molecular weight siloxane does not volatilize from the hybrid composition or the volatilization amount becomes extremely small.

  As described above, the hybrid composition according to the present invention can be used as a heat-resistant adhesive material and a heat-conductive material having higher quality than those of conventional ones.

[Second invention]
The silicate compound is represented by [Chemical Formula 1] SinO (n-1) (RO) 2 (n + 1) (R = alkyl group, n = 4 to 16). [Chemical Formula 2] SinO (n-1) (RO) 2 (n + 1) (OSi (CH3) 2) m (RO) 2 (n + 1) SinO (n-1) (R = alkyl group, n = 4 to 16, It may be represented by m> 50).

[Third invention]
Moreover, it is preferable that the mixing | blending ratio of the said silicate compound (A) and the said modified | denatured PDMS (B) is the range of 0.1-10, in the molar ratio of A / B. The optimum blending ratio is around 1 in terms of A / B molar ratio.

  The hybrid composition of the present invention increases the modified PDMS (B) when flexibility is required, and increases the silicate compound (A) when high hardness is required. It is good to let them.

  However, when the silicate compound (A) is increased in the hybrid composition of the present invention, when the molar ratio exceeds 10, the volatile component of the low molecular siloxane increases, that is, the amount of the low molecular siloxane present alone is increased. For this reason, problems such as shrinkage and thinning during curing and occurrence of cracks in some cases occur, and the effects of the present invention are not achieved.

  On the other hand, when the molar ratio is less than 0.1, the hydrolysis reaction and condensation reaction between the silicate compound (A) and the modified PDMS (B) are not performed smoothly, resulting in an uncured state, and low molecular siloxane remains. Therefore, the effect of the present invention is not achieved.

  The silicate compound is preferably a trimer to a 12-mer (a trimer to a 12-mer). This is because, if it is less than a trimer, the effect of the characteristics of the silicate is small, and if it is higher than the 12-mer, the viscosity of the silicate compound is high, and it is difficult to handle at the time of synthesis.

  The present invention can provide a hybrid composition with very little or no residual low molecular weight siloxane.

Hereinafter, examples for more specifically explaining the present invention will be described.
In the examples, “part” and “%” are based on mass (mass part, mass%) unless otherwise specified.

[Production of hybrid composition]
In a reaction vessel equipped with a stirrer, a thermometer, and a dropping line, 1.0 g of ethyl silicate (manufactured by Tama Chemical Co., Ltd., silicate 40 n = 4 to 6 or silicate 45 n = 6 to 8) is added, and ethyl silicate is added. Polydimethylsiloxane modified with alkoxy at both ends (mass average molecular weight; equivalent to 32,000) (HBSIL039 manufactured by Arakawa Chemical Co., Ltd.) is stirred and mixed in the atmosphere (room temperature) for about 30 minutes. A certain raw material liquid A was obtained.
Here, silicates having the same type and the same characteristics were used as silicates used in ethyl silicate and polydimethylsiloxane obtained by alkoxy-modifying ethyl silicate at both ends.

Then, in the hydrolysis step and the condensation step, the raw material liquid A was added dropwise with a required amount of 0.93 g of water over about 1 hour and stirred and mixed.
Then, it naturally cooled to room temperature over about 30 minutes, stirring, and obtained the hybrid composition.

[Evaluation]
(Measurement specimen sheet)
The hybrid composition described above was poured into a Teflon petri dish (diameter 103 mm) to a final thickness of 1 mm, dried and baked at 200 ° C. for 2 hours, then demolded from the Teflon petri dish, and a measurement test piece. A sheet (diameter: 103 mm, thickness: 1 mm) was used.

(silicone rubber)
In addition, as a conventional silicone rubber to be compared, a commercially available SR-50 manufactured by Tigers Polymer Co., Ltd. was adopted to prepare a sheet having a diameter of 103 mm and a thickness of 1 mm.

(Evaluation equipment)
In order to measure the remaining amount of cyclic siloxane which is a volatile component of low-molecular-weight siloxane, the evaluation apparatus is a cooled injection system (hereinafter referred to as “TDU”) (Gertel) of a heated desorption unit (hereinafter referred to as “TDU”). , Abbreviated as “CIS”.) A gas chromatograph mass spectrometer (Gas Chromatography Mass Spectrometry (hereinafter abbreviated as “GC-MS”)) was used. The GC-MS apparatus is a 5975B system manufactured by Agilent Technologies.

(Evaluation methods)
In order to vaporize the volatile components in the sample, heating was performed while flowing helium gas through the sample in the sample holder by TDU. And after making the outgas vaporized in helium adsorb | suck to the adsorption tube in a CIS unit, the outgas collected by the adsorption tube was flowed to GC-MS apparatus, and the kind and quantity of the volatile component were measured. The column of the GC-MS apparatus is a capillary column (liquid layer: phenylmethylsiloxane).

(Details of measurement conditions)
The heating unit was heated by TDU at 160 ° C./min from 40 ° C. to 200 ° C. (hold time 5 minutes), and mass spectrometry was performed through an inert capillary tube (temperature: 350 ° C.).

The GC-MS apparatus has an inlet temperature: −150 ° C. to 12 ° C./second to 325 ° C., a column: Agilent 19091S-433 (column length 60 m, column inner diameter 0.25 mm, column film thickness 0.25 μm), oven: 40 ° C. -25 ° C / min to 300 ° C (hold time 10 minutes), helium flow rate: 1.2 mL / min, MS ion source temperature 230 ° C: MS quadrupole temperature: 150 ° C, MS ionization voltage: 69.9 eV), Scan range: m / z 100-1000
It is. Here, MS is an abbreviation for Mass Spectrometry.

(Evaluation results)
The evaluation results are shown in Table 1. According to Table 1, when a measurement test piece sheet made of the hybrid composition according to the present invention is compared with a conventional silicone rubber, the conventional silicone rubber has a valence of 3 to 15 and volatilization of cyclic siloxane is observed. The test specimen sheet shows no volatilization of cyclic siloxane. That is, it can be seen that the low-molecular siloxane does not remain in the hybrid composition according to the present invention.

In Table 1, the vertical axis represents the volatilization amount, “0.00E + 00” means 0.00 × 10 ^0, that is, 0, and “3.50E + 08” means 3.50 × 10 ⁸ .
The volatilization amount is expressed as a peak area, and the unit is Counts (abbreviated as “ct”). The horizontal axis is the valence of cyclic siloxane.

  The above-described embodiments have been illustrated for the purpose of explanation, and the present invention is not limited thereto. The present invention can be recognized by those skilled in the art from the scope of the claims and the description. Modifications, deletions, and additions are possible as long as they do not violate the technical idea.

  In the above-mentioned examples, silicates having the same type and the same characteristics were used as ethyl silicate and silicate used in polydimethylsiloxane obtained by alkoxy-modifying ethyl silicate at both ends. In this case, since they have similar reactivity, the reaction rate is about the same, which is preferable.

  However, the present invention is not limited to this, and silicates of different types and characteristics (for example, when using ethyl silicate and methyl silicate, when using ethyl silicates having different purity) may be used. . In this case, since a difference occurs between the reaction rates, it is necessary to adjust the synthesis time to make the reaction rates the same and to change the manufacturing conditions.

  The hybrid composition according to the present invention can be used as a heat-resistant adhesive material or a heat conductive material in which the amount of low molecular siloxane remaining is extremely small or not contained at all.

However, in trace amounts in high- Brides materials are listed in silicone rubber, and non-patent document 1 disclosed in Patent Documents 1 to 3 but has residual low molecular weight siloxanes, low-molecular-weight siloxane is volatilized The generation of cyclic siloxane causes the following problems. In other words, in the electrical and electronic fields that use silicone rubber, this cyclic siloxane adheres to the surface of electrical contacts such as terminals, and becomes an insulating film, resulting in contact failure, causing problems such as poor conduction and malfunction. is doing.

Claims (3)

A silicate compound;
A mixture having a terminal silicate-modified polydimethylsiloxane,
A hybrid composition obtained by a hydrolysis reaction and a condensation reaction. The silicate compound is
[Chemical Formula 1] SinO (n-1) (RO) 2 (n + 1) (R = alkyl group, n = 4 to 16)
And
The terminal silicate-modified polydimethylsiloxane is
[Chemical Formula 2] SinO (n-1) (RO) 2 (n + 1) (OSi (CH3) 2) m (RO) 2 (n + 1) SinO (n-1)
(R = alkyl group, n = 4 to 16, m> 50)
The hybrid composition of Claim 1 represented by these. The silicate compound (A);
The blending ratio of the terminal silicate-modified polydimethylsiloxane (B) is:
3. The hybrid composition according to claim 1, wherein the A / B molar ratio is in the range of 0.1 to 10 inclusive.