JP2009242558A - Siloxane prepolymer, silicone resin, and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a siloxane prepolymer reducing steps in production of the siloxane prepolymer with high introduction efficiency of dialkoxydialkylsilanes having a polymerizable ethylenically unsaturated double bond; a siloxane prepolymer obtained by the production method; and a silicone resin for an optical material excellent in optical properties utilizing it. <P>SOLUTION: Condensation reaction using a prepolymerized catalyst as an amine-type catalyst eliminates a neutralization step and produces a siloxane prepolymer with high quality without impairing optical properties such as transparency and refractive index, and further enhances introduction of a dialkylsiloxane group having a polymerizable ethylenically unsaturated double bond. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a siloxane prepolymer having a polymerizable ethylenically unsaturated bond in the molecule, a method for producing the same, and a silicone resin having a polymerizable ethylenically unsaturated bond in the molecule. More specifically, a siloxane prepolymer having a polymerizable ethylenically unsaturated bond in the molecule, in which the introduction efficiency of the polymerizable ethylenically unsaturated bond group is enhanced and the separation and purification process of the prepolymer is simplified, and a method for producing the same And a silicone resin having in its molecule a polymerizable ethylenically unsaturated bond having optical properties as a light modulating material when the prepolymer is subjected to a condensation reaction.

  Silicone resin is not only flexible and rich in electrical insulation, but also has excellent light transmittance and characteristics as an optical material. Such a silicone resin can be produced by directly polymerizing a silane monomer, or once the silane monomer is made into dialkyl (diaryl) siloxanes or prepolymers at both terminal silanol groups.

  Siloxane prepolymers are particularly advantageous in processing into optical elements and filters because they can control the mixing and dispersibility of the components when producing silicone resins.

  Examples of the siloxane prepolymer include a low molecular weight organopolysiloxane having a linear or branched structure, and such a siloxane prepolymer includes a monomer (monomer) to be used, a large amount having a relatively small molecular weight. For example, when the repeating unit of SiO is the main chain and the substituent bonded to Si is the side chain by selecting the body, catalyst, and synthesis conditions, a variety of structures and functions are available depending on the type of repeating unit and substituent and the number of substitutions. It is possible to obtain a siloxane prepolymer having a variety of silicone resins and polymer compounds having a siloxane group.

  However, on the other hand, depending on the choice of the monomer, catalyst, or synthesis conditions to be used, the introduction rate of the functional group may decrease as the reaction rate decreases, or impurities may be mixed in. Alternatively, even if further purification is performed, it may not be used in the light control material application.

  In this technical field, among siloxane prepolymers, siloxane prepolymers having reactive functional groups that react with organic groups are crosslinked, three-dimensional networks using compounds that generate radicals and cations by heat, light, etc. A siloxane prepolymer having a reactive functional group that reacts with an organic group can be led to a structure, and a silicone resin having a reactive functional group that reacts with an organic group is produced by a condensation reaction. It is suitable at the point which can do.

  The silicone resin having a reactive functional group that reacts with the organic group can obtain a modified silicone resin by reacting not only with silicone resins but also with various resin-forming materials other than silicone resins. Excellent convenience. This modified silicone resin takes various shapes, but when processed into an optical element or filter, a cured cured silicone resin can be obtained by reacting with a reactive functional group. Excellent features such as control of optical properties and ease of processing.

  Examples of such reactive functional groups include amino groups, vinyl groups, epoxy groups, mercapto groups, chloro groups, etc., but vinyl groups are preferred for the purpose of obtaining a silicone resin having excellent optical properties in the present invention. A polymerizable ethylenically unsaturated double bond is preferred.

  As a conventional method for producing a silicone resin having a polymerizable ethylenically unsaturated bond in the molecule having optical characteristics, the following methods are known.

  One or more kinds of linear both-end silanol group dialkyl (diaryl) siloxanes and dialkoxydialkylsilanes (A) having a polymerizable ethylenically unsaturated double bond are prepared from tin (II) 2-ethylhexanoate. Using such a polymerization catalyst (polymerization catalyst), a dehydration condensation reaction is carried out by azeotropy in a hydrocarbon solvent to condense to a predetermined degree of polymerization. A method for obtaining a resin is disclosed (Patent Document 1).

  It is described that the silicone resin obtained by the method of Patent Document 1 can be made into an optical material by adjusting the refractive index according to the relative introduction ratio of the side chain alkyl group and aryl group to the siloxane main chain.

  However, in the method of Patent Document 1, since the introduction efficiency is low due to low reactivity of dialkoxydialkylsilanes having a polymerizable ethylenically unsaturated double bond, the dialkoxy having an unsaturated ethylenic double bond is not suitable. It was difficult to freely adjust the introduction ratio of alkoxydialkylsilanes. In addition, regarding the ratio of the alkyl group and the aryl group, it is necessary to separate and purify the ratio of the alkyl group and the aryl group in the raw material silanol group dialkyl (diaryl) siloxane itself within a suitable range in advance. It was difficult to adjust freely during resin production. Similarly, dialkyl (diaryl) siloxanes at both ends of the raw material are usually mixed with cyclic impurities that do not undergo a condensation reaction at a ratio of about 30%. It had to be purified. Furthermore, the method of Patent Document 1 has a drawback in that it is difficult to control the reaction during the condensation reaction, and the polymerizable ethylenically unsaturated double bond suddenly starts to polymerize and may cause gelation.

  On the other hand, the present applicant did not use dialkyl (diaryl) siloxanes at both terminals in advance, but dialkoxydialkylsilanes having a polymerizable ethylenically unsaturated double bond, dialkoxydialkylsilanes, and diarylsilanediols. Starting materials, and using an inorganic base such as potassium hydroxide as a prepolymerization catalyst to accelerate the reaction, produce a siloxane prepolymer at one time, neutralize with an acidic neutralizing agent, and then separate the liquid. After purifying the siloxane prepolymer, a dehydration condensation reaction is carried out by azeotropic distillation in a hydrocarbon solvent using a condensation catalyst (polymerization catalyst) such as tin (II) 2-ethylhexanoate. A method is disclosed in which a silicone resin is obtained by condensing to a degree of polymerization and adding an end-capping agent to seal the ends (Patent Document 2). .

  According to the method of Patent Document 2, dialkoxydialkylsilanes having a polymerizable ethylenically unsaturated double bond and other silanes can be prepolymerized by condensation reaction. The process of separating and purifying cyclic impurities is not required during the pre-preparation of terminal silanol group dialkyl (diaryl) siloxanes, can be produced in a short time, and the ratio of alkyl groups to aryl groups can be freely adjusted during the synthesis of the siloxane prepolymer. On the other hand, in order to use an inorganic base as a prepolymerization catalyst, the synthesis | combination of a siloxane prepolymer requires the process of neutralization and separation / purification for removing this inorganic base. Furthermore, during separation and purification, the water layer containing the neutralized product of the inorganic base to be removed is mixed with a water-soluble low molecular weight silane compound, not only reducing the yield of the product, but also during the waste liquid treatment of the aqueous layer, There was a problem that noncombustible silicon dioxide was produced during combustion. Moreover, the introduction efficiency of dialkoxydialkylsilanes having a polymerizable ethylenically unsaturated double bond was not sufficient.

US Pat. No. 6,416,827 (Example. 7) JP2004-162060 (4th page, 9th to 10th page)

  INDUSTRIAL APPLICABILITY The present invention can simplify the process for producing a siloxane prepolymer, and provides a method for producing a siloxane prepolymer with high introduction efficiency of dialkoxydialkylsilanes having a polymerizable ethylenically unsaturated double bond, and the production method. An object of the present invention is to provide a siloxane prepolymer and a silicone resin for an optical material having an excellent optical property using the siloxane prepolymer.

  As a result of intensive studies in view of the above circumstances, the inventors have found that when the prepolymerization catalyst is an amine-based catalyst, a neutralization step is unnecessary, and high quality siloxane is obtained without impairing optical properties of transparency and refractive index. A prepolymer was obtained, and it was found that introduction of a dialkylsiloxane group having a polymerizable ethylenically unsaturated double bond could be enhanced, and the present invention was completed.

  That is, the present invention is synthesized using dialkoxydialkylsilanes (A) having a polymerizable ethylenically unsaturated double bond, dialkoxydialkylsilanes (B), and dialkylsilanediols (C) as starting materials. The present invention relates to a prepolymer, a production method thereof, and a silicone resin having a polymerizable ethylenically unsaturated double bond using the same.

  According to the method for producing a siloxane prepolymer of the present invention, the step of separating the catalyst and the prepolymer in the siloxane prepolymer production step can be simplified and the dialkoxy having a polymerizable ethylenically unsaturated double bond in the molecule. Silicone which can introduce dialkylsilanes with high efficiency and has a polymerizable ethylenically unsaturated double bond in the molecule having a cured product forming ability excellent in curability and smoothness using the siloxane prepolymer. There is an exceptional effect that a resin can be obtained.

Hereinafter, the present invention will be described in detail.
The siloxane prepolymer of the present invention forms a silicone resin having a polymerizable ethylenically unsaturated double bond in the molecule by a condensation reaction while retaining the polymerizable ethylenically unsaturated double bond. A silicone resin can be cured with ultraviolet rays or an electron beam using a polymerizable ethylenically unsaturated double bond possessed by, to obtain a cured product.

  The siloxane prepolymer of the present invention is a siloxane obtained by condensation reaction using one or more silanes selected from silanes having a dialkoxy group and one or more silanes selected from silanes having a disilanol group as starting materials. The siloxane prepolymer of the present invention can be obtained by a condensation reaction between these silanes.

  In the siloxane prepolymer of the present invention, among silanes having a dialkoxy group, silanes having a dialkoxy group having at least one reactive group in the molecule are used. By using silanes having a functional group that reacts with at least one organic group, the silicone resin having a functional group that reacts with at least one organic group obtained by the condensation reaction of the siloxane prepolymer is cured by ultraviolet rays or electron beams. In this case, a three-dimensional cross-link can be formed by the side chain reactive group, and a silicone resin with adjusted optical characteristics can be produced with good reproducibility.

  Examples of such reactive functional groups include amino groups, vinyl groups, epoxy groups, mercapto groups, and chloro groups. Among them, polymerizable ethylene-based polymers are used for the purpose of obtaining silicone resins having excellent optical properties in the present invention. A reactive functional group having a vinyl group that is an unsaturated double bond is preferred. Examples of the alkyl group having a polymerizable ethylenically unsaturated double bond of dialkoxydialkylsilanes having a polymerizable ethylenically unsaturated double bond include vinyl, styryl, acryloxy and methacryloxy groups.

  Such an alkyl group having a polymerizable ethylenically unsaturated double bond was obtained from a dialkoxydialkylsilane (A), and the alkyl group having a polymerizable ethylenically unsaturated double bond was obtained from a siloxane prepolymer. Necessary when a silicone resin having a polymerizable ethylenically unsaturated double bond is cured by a three-dimensional crosslinking reaction, and the alkyl group includes an acryloxy group having 1 to 4 carbon atoms and a carbon number. An acryloxyalkyl dialkoxysilane having a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms which may be the same or different, and having a dialkoxysilane group as a structural unit It is selected from at least one kind.

  Depending on the number of carbon atoms of the alkyl group formed by bonding the acryloxy group, the cross-linking distance in the cured product can be controlled. The number of carbon atoms of the alkyl group formed by bonding an acryloxy group in the present invention is from the point of view of optical properties such as the reactivity and the hardness and refractive index of the obtained silicone resin, and the silicone resin. 4 linear or branched alkyl groups are preferable, and examples of such an alkyl group having a polymerizable ethylene double bond include an acryloxymethyl group, an acryloxypropyl group, and a (meth) acryloxypropyl group. It is done.

  Of these, dialkoxydialkylsilanes having a polymerizable ethylenically unsaturated double bond are particularly preferred from the viewpoints of reactivity and ultraviolet curing when the compound is represented by compound (I).

  Formula (I)

In the formula (I), R ¹ is a lower alkyl group, R ² is hydrogen or a methyl group, and the R ³ group is a lower alkyl group, and a methyl group having particularly little steric hindrance is used.

In the formula, R ¹ is particularly preferably a methyl or ethyl group because of high reactivity. Further, when R ^{2 in the} formula is particularly hydrogen, the ultraviolet curing ability is high and preferable. Further, when the R ³ group is a methyl group, the steric hindrance is small and particularly preferable.

  In the present invention, the dialkoxydialkylsilane (B) is a compound represented by the following formula (II).

Formula (II)

In the formula (II), R ⁴ is a lower alkyl group, a dialkyl group which is an allyl group or an aryl group, and R ⁵ is a lower alkyl group.

If R ^{4 in the} formula (II) is a methyl or ethyl group, it is preferably used because of its high reactivity. R ⁵ is a lower alkyl group, and R ⁵ is a methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl group, and these are the alkoxy group hydrolysis reactions. Good and preferred. Among them, it is particularly preferable that R ⁵ is a methyl group because hydrolyzability is particularly high.

  In the present invention, the silanes (C) having a disilanol group are compounds represented by the following formula (III).

  General formula (III)

In the formula (III), R ⁶ is a lower alkyl group or an aryl group.

In the formula (III), R ⁶ is an aromatic ring such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl group, lower alkyl group, phenyl group, tolyl group, xylyl group, etc. The group is applicable. If R ⁶ is an aromatic ring, it can be suitably used from the viewpoint of reaction control.

In the present invention, diarylsilanediols in which R ⁶ is an aromatic ring are represented by the general formula (IV).

  Formula (IV)

In formula (IV), R ⁷ may have a lower alkyl group.

  When the siloxane prepolymer of the present invention is selected from, for example, silanes having one side chain for each of (A), (B), and (C), the disiloxane having a polymerizable ethylenically unsaturated double bond is selected. Produced using acryloxypropylmethyldimethoxysilane as the alkoxydialkylsilane (A), dimethyldimethoxysilane as the dialkoxydialkylsilane (B), and diphenylsilanediol as the silane (C) having a disilanol group. (A) acryloxypropylmethyldimethoxysilane, (B) diphenyldimethoxysilane, and (C) dimethylsilanediol may be used, but the former is more effective than (B) and (C). The reactivity is comparable, and the yield of the reaction product is also high, which is preferable.

  In the siloxane prepolymer of the present invention, the ratio of dialkyl group (Branch (1)), dimethyl group (Branch (2)) and diphenyl group (Branch (3)) having a polymerizable ethylenically unsaturated double bond is the amount charged. Can be changed freely. Prepolymers polymerized so that (1) :( 2) :( 3) = 0 to 50:50 to 100: 0 to 40 in terms of moles are preferable because they can be colorless and transparent. Furthermore, the prepolymer produced so that (1) :( 2) :( 3) = 1 to 35:75 to 90:10 to 25 has a refractive index suitable when it is made into a silicone resin by a condensation reaction, Particularly preferred. In other words, the silanes (A) having a polymerizable ethylenically unsaturated double bond can be introduced up to 0.1 to 30 mol% of the entire starting material, and 0.5 to 30 mol% is introduced. The hardness and smoothness of the cured product cured by ultraviolet rays or electron beams are more preferable. In particular, the introduction of up to 10 mol% to 30 mol% to obtain a cured product having excellent optical properties is a remarkable effect that has not been achieved in the past.

  Moreover, since the siloxane prepolymer obtained by this invention introduces acryloxyalkyl dialkoxysilane (A) at random into the siloxane prepolymer, the silicone resin using the siloxane prepolymer is further cured. At this time, the cross-linking points are dispersed to increase the curability of the cured product, and it is easy to perform optical control.

  When a trifunctional silane compound is used as the silanes (B) having a dialkoxy group and the silanes (C) having a disianol group used in the siloxane prepolymer of the present invention, a three-dimensional crosslinking reaction occurs during prepolymerization. Therefore, it is easy to gel and is not preferred, but it is preferable to use a silane which is a bifunctional silane compound because a transparent and good siloxane prepolymer can be obtained without causing this gelation.

  The siloxane prepolymer of the present invention is a siloxane prepolymer having a polystyrene-equivalent weight average molecular weight (Mw) of 1,000 or less, resulting in a high yield of the reaction product. This is preferable because a suitable siloxane prepolymer capable of suppressing size variation can be obtained.

  In addition, the siloxane prepolymer of the present invention preferably has a silanol group at the end in order that the polystyrene-reduced weight average molecular weight (Mw) is in the range of 1,000 or less and further undergoes a condensation reaction to form a silicone resin.

  In this invention, a weight average molecular weight can be calculated | required by the measured value of size exclusion chromatography (SEC) using standard polystyrene (MW104-3,840,000).

  In the present invention, the introduction rate of dialkoxydialkylsilanes having a polymerizable ethylenically unsaturated double bond in the siloxane prepolymer can be defined by proton nuclear magnetic resonance spectrum (1H-NMR).

  In the siloxane prepolymer of the present invention, a prepolymerization step for polymerizing silanes with an organic amine catalyst, and a catalyst removal step for removing low-boiling dialkoxydialkylsilanes, reaction byproducts, and organic amine catalysts are sequentially performed. Can be obtained by: Furthermore, a silicone resin can be obtained by a condensation reaction step in which the obtained siloxane prepolymer is polymerized in the presence of a catalyst.

  More specifically, the prepolymerization step in the present invention is carried out by dialkoxydialkylsilanes (A) having a polymerizable ethylenically unsaturated double bond, dialkoxydialkylsilanes (B), and diarylsilanediols (C ), An organic amine catalyst and water are added, and the mixture is heated and stirred to obtain a prepolymer.

  Since the organic amine of the catalyst in the present invention can be heated and distilled together with the solvent in the system after the production of the prepolymer, neutralization or separation of the inorganic base required when the inorganic base of the catalyst is used. A separation / removal step such as removal is not necessary, and thus the step can be simplified, and the amount of solvent used for washing can be reduced. Furthermore, since the prepolymer has no volatility, it is possible to suppress the generation of non-combustible silicon dioxide during combustion even when the aqueous layer obtained by distillation is treated with waste liquid.

  As the catalyst used for the polymerization reaction of siloxane, an acidic catalyst is also known. However, the use of an acidic catalyst is not preferable because the reactivity of diarylsilane diols is lowered. In particular, in the case of silanol having a diphenyl group, the decrease in reactivity becomes remarkable.

  If the boiling point is 60 ° C. or higher, the organic amine of the catalyst in the present invention can suppress volatilization during the production of the prepolymer and exhibits excellent catalytic ability even when the addition amount is small. Since it can reduce more, it is more preferable. A boiling point of 60 to 120 ° C. at normal pressure is particularly preferable because the organic amine can be completely removed by a general distillation method of an aqueous solution. That is, a particularly preferred catalyst is an aliphatic or aromatic amine having a boiling point of 60 to 120 ° C. at normal pressure.

  Examples of the organic amine having a boiling point of 60 to 120 ° C. include triethylamine, N, N-diethylmethylamine, N-methylpyrrolidine, butylamine, N, N-dimethylisopropylamine, diisopropylamine, N, N-dimethylbutylamine, and isopentyl. Examples include amine, pentylamine, dipropylamine, N-methylpiperidine, N-methylpyrrole, and pyridine. These organic amines may be used alone or in combination of two or more.

  The concentration of the organic amine is 0.03 to 0.5% by mass (0.1 to 0.1%) when the state in which the organic amine and water are added to (A), (B) and (C) is 100% by mass. 0.4% by mass is preferable, and it is preferable to use a 0.1 to 1% by mass aqueous solution for use). Within this concentration range, the catalyst can be sufficiently removed, and a transparent silicone resin can be obtained as a light control material after the condensation reaction, which can be sufficiently used in terms of optical properties. If it is higher than the concentration range, even an organic amine having a boiling point in the range of 60 to 120 ° C. cannot be completely removed in the catalyst removal step, and the silicone resin as the light modulating material after the condensation reaction becomes cloudy and is used for optical properties. I can't do that. Further, this concentration range is preferable because the reaction proceeds smoothly and the time required for production can be shortened.

  In this step, it is preferable that the reaction temperature is higher than 40 ° C. because the reaction can be accelerated and the time required for production can be shortened. If the reaction temperature is lower than 120 ° C., the ester bond contained in the dialkoxydialkylsilane (A) having a polymerizable ethylenically unsaturated double bond is less susceptible to hydrolysis, and the polymerizable group is a reactive group. This is preferable because the reaction yield of the silicone resin having an ethylenically unsaturated double bond can be increased. A reaction temperature of 60 to 90 ° C. is particularly preferable because it is easy to control the temperature during the production time, and the reaction can proceed rapidly without undergoing hydrolysis of the ester bond.

  The catalyst removal step in the present invention is carried out for the purpose of removing alcohol generated by hydrolysis of the organic amine catalyst, water and alkoxysilanes following the prepolymerization. As a specific method, the mixture after prepolymerization may be carried out at a reduced pressure of 5 hPa or less using an apparatus such as an evaporator, or carbonization of heptane, 2,2,4-trimethylpentane or the like. A hydrogen-based solvent may be added and removed azeotropically at normal pressure. It is possible to select appropriately according to the scale of the reaction. When the reaction is sufficiently advanced in the prepolymerization step, the residual amount of dialkoxydialkylsilanes having a low boiling point can be reduced, and the silicon content in the waste liquid can be reduced. It has an excellent feature that it can be reduced.

  In this way, conventionally, since an inorganic base was used as a catalyst, it was necessary to separate a layer containing a siloxane prepolymer and an aqueous layer in advance and then remove water and alcohol. It becomes unnecessary, and the manufacturing process of a siloxane prepolymer is simplified.

  In the condensation reaction step of the present invention, a hydrocarbon solvent such as heptane or 2,2,4-trimethylpentane is added to the prepolymer that has undergone the catalyst removal step, so that tin (II) 2-ethylhexanoate is used. In this step, a silicone resin is obtained by azeotropic dehydration in the presence of a suitable condensation catalyst (polymerization catalyst).

  The dehydration in the condensation reaction step of the present invention may be carried out by attaching a device typified by a Dean-Stark trap, or by a packed column packed with a dehydrating agent such as molecular sieve, and is appropriately selected according to the scale of the reaction. It is possible.

  When the obtained silicone resin has a molecular weight of 10,000 to 100,000, a hardness suitable for an optical material can be obtained when this is used as a cured product. Furthermore, when it is 50,000-100,000, the hardened | cured material excellent as an optical material is obtained from points, such as workability, the moldability, and dimensional stability, and it is especially preferable.

  The degree of polymerization can be determined from the amount of water produced by dehydration during the condensation reaction or the decrease in the peak area of the overtone vibration of silanol groups in the reaction solution using a near-infrared spectrophotometer. Is possible.

  The silicone resin of the present invention is a polymerizable ethylenically unsaturated polymer obtained by a condensation reaction while retaining the polymerizable ethylenically unsaturated double bond of a siloxane prepolymer having a polymerizable ethylenically unsaturated double bond in the molecule. It is a silicone resin having a double bond in the molecule.

  The silicone resin obtained by the present invention changes in properties depending on the molar ratio between the intramolecular organic residue and silicon, and the larger the molar ratio, the more flexible and rich in elasticity. Further, in contrast between those having the same molar ratio, the more the number of carbon atoms in the intramolecular organic residue, the more flexible the silicone resin. Among them, those in which an intramolecular organic residue is substituted with a methyl group or an alkyl group other than a methyl group and / or an aryl group have good heat resistance and moisture resistance, and are excellent in electrical performance and optical performance.

  The silicone resin of the present invention can control the optical performance by the characteristics of the functional group of the siloxane prepolymer, and is a polymer that supports suspended particles in a suspended particle device such as a light valve (light valve). The medium can be suitably used in the form of a film or the like. As described in Japanese Patent Application Laid-Open No. 2005-300962 filed by the present applicant, the refractive index difference between the refractive index of the silicone resin and the medium in the suspended particles is in the range of +0.0021 to +0.0080. By controlling the refractive index of the silicone resin, a silicone resin suitable as an optical material can be obtained.

  The silicone resin obtained by the condensation reaction step of the present invention can be further cross-linked by a reaction of a polymerizable ethylenically unsaturated double bond with ultraviolet rays or an electron beam to obtain a cured product.

  The terminal silanol group of the silicone resin obtained by the condensation reaction step of the present invention may be further sealed with an alkyl group or a monofunctional silane compound, but if the molecular weight is within the range of 50,000 to 100,000. Since the reaction frequency between terminal silanol groups is low and the phenomenon that the molecular weight increases during storage is not observed, it is not always necessary to seal.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not restrict | limited at all by these examples.

  In this example, the refractive index is measured by an Abbe refractometer, the viscosity is measured by an R-type viscometer, and the silicon content is measured by ICP analysis.

  In a 500 mL four-necked flask equipped with a reflux condenser and a temperature sensor, 3.8 g of 3-acryloxypropyldimethoxymethylsilane (KBM-5102 manufactured by Shin-Etsu Chemical Co., Ltd.), 44 dimethoxydimethylsilane (LS-520 manufactured by Shin-Etsu Chemical Co., Ltd.) 44 .9 g, 21.1 g of diphenylsilanediol (LS-4320 manufactured by Shin-Etsu Chemical Co., Ltd.), 0.2 g of triethylamine (first grade reagent manufactured by Wako Pure Chemical Industries, boiling point 88.8 ° C.) as an organic amine catalyst, and 49.8 g of distilled water were added. The mixture was heated and stirred at 81 to 83 ° C. for 6 hours. After the Dean Stark trap was attached to the flask, 200 mL of heptane (first grade reagent manufactured by Kokusan Kagaku) was added and heated to reflux for 2 hours. At this time, the internal temperature rose from 75 ° C. to 102 ° C. As a result, 62.3 g of an aqueous layer containing methanol was distilled out. When the silicon content in the distillate layer was analyzed by ICP analysis, it was 0.4%.

(Comparative Example 1)
96 g of 3-acryloxypropyldimethoxymethylsilane (KBM-5102 manufactured by Shin-Etsu Chemical Co., Ltd.), 1228 g of dimethoxydimethylsilane, 352 g of diphenylsilanediol, 0.1 mass in a 5 L four-necked flask with a stirring device and an extraction cock at the bottom A 480 g% potassium hydroxide aqueous solution was added, and the mixture was stirred at room temperature for 5 hours. After adding 10 mL of 10 mass% acetic acid aqueous solution and 1500 mL of heptane, it stirred for 5 minutes and left still. At this point, the liquid separated into two layers. After removing the lower layer from the lower cock, the heptane layer remaining in the flask was washed with 500 mL of water three times. When all the obtained water layers were analyzed for silicon by ICP analysis, it was 3.0%.

In a 300 mL flask equipped with a stirrer and a condenser tube, 3.8 g of 3-acryloxypropyldimethoxymethylsilane (silanes (A) KBM-5102 manufactured by Shin-Etsu Chemical Co., Ltd.), dimethoxydimethylsilane (silanes (B) Shin-Etsu Chemical Co., Ltd.) Company LS-520) 44.9g, Diphenylsilanediol (Silanes (C) Shin-Etsu Chemical Co., Ltd. LS-4320) 21.1g, Triethylamine (boiling point 88.8 ° C, Wako Pure Chemical Reagent grade) as organic amine catalyst ) And 49.8 g of water were heated and stirred at 81 to 83 ° C. for 6 hours. When the obtained reaction product was evaporated at 60 ° C. and 2 hPa, 49.8 g of a colorless and transparent prepolymer was obtained.
To a 500 mL four-necked flask equipped with a stirrer, a temperature sensor, and a Dean-Stark trap, 44.0 g of the obtained prepolymer and 190 mL of heptane (first grade reagent manufactured by Kokusan Chemical) were added and heated to reflux for 1 hour. At this time, a small amount of water flowed out. Then, a solution prepared by dissolving about 40 mg of tin (II) 2-ethylhexanoate in about 1 mL of heptane was added to start the condensation reaction. When reacted at the reflux temperature for 110 minutes, about 1.9 to 2.4 mL of condensation reaction water was distilled. After 200 mL of ethanol and 200 mL of methanol were added to the reaction solution for liquid separation operation, it was left overnight. When the lower layer of the liquid separated into two layers was evaporated at 60 ° C. and 2 hPa, 35.3 g of a silicone resin having a colorless transparent oily polymerizable ethylenically unsaturated double bond in the molecule was obtained. When the upper layer was evaporated at 60 ° C. and 2 hPa, 8.1 g of a colorless liquid containing low molecular weight impurities was obtained.

  Except that N-methylpyrrolidine (boiling point 80-81 ° C., Wako Pure Chemical Reagent grade) was used as the organic amine catalyst, the same procedure as in Example 2 was carried out to obtain 50.0 g of a colorless transparent prepolymer. When 44.0 g was subjected to a condensation reaction in the same manner as in Example 1, 33.4 g of a silicone resin was obtained. The colorless liquid having low molecular weight impurities was 8.8 g.

  Except for using diisopropylamine (boiling point 84 ° C., Wako Pure Chemical Reagent grade 1) as the organic amine catalyst, the same procedure as in Example 2 was carried out to obtain 49.7 g of a colorless and transparent prepolymer. When a condensation reaction was carried out in the same manner as in Example 1, 35.2 g of a silicone resin was obtained. The colorless liquid having low molecular weight impurities was 7.8 g.

  Except that 2-dimethylaminoethanol (boiling point 134-136 ° C., Wako Pure Chemical Reagent grade) was used as the organic amine catalyst, the same procedure as in Example 2 was carried out to obtain 49.4 g of a colorless and transparent prepolymer. When 44.0 g of this was subjected to a condensation reaction in the same manner as in Example 1, 28.4 g of a silicone resin was obtained. The colorless liquid having low molecular weight impurities was 14.3 g.

  Except that triethanolamine (boiling point at 7 hPa of 190 to 193 ° C., Wako Pure Chemical Reagent grade) was used as the organic amine catalyst, the same procedure as in Example 2 was carried out to obtain 49.1 g of a colorless and transparent prepolymer. When 44.0 g of this was subjected to a condensation reaction in the same manner as in Example 1, 24.7 g of a silicone resin was obtained. The colorless liquid having low molecular weight impurities was 17.3 g.

About the fluidity | liquidity evaluation of each silicone resin, it evaluated in the following way.
0.02g was dripped on glass, it stood still at 90 degree | times, and it evaluated by the length of the liquid dripping after 1 minute.
◎ Liquid sag is less than 1cm ○ Liquid sag is 1cm to 3cm
△ Liquid dripping is 3cm ~ 5cm
X Liquid dripping is over 5 cm.

  The following table shows the molar ratio of the charge during the production of the siloxane prepolymer, and the analysis results of the weight-average molecular weight, refractive index, and viscosity of the obtained silicone resin in terms of polystyrene.

Table 1 Charge molar ratio of each silane and measurement result of the obtained silicone resin

  In a 300 mL flask equipped with a stirrer and a condenser tube, 44.9 g of dimethoxydimethylsilane (silanes (B)), 21.1 g of diphenylsilanediol (silanes (C)), 3-acryloxypropyldimethoxymethylsilane (silanes) (A)) 3.8 g, 0.2 g of triethylamine as an organic amine catalyst, and 49.8 g of water were heated and stirred at 81 to 83 ° C. for 6 hours. When the obtained reaction product was evaporated at 60 ° C. and 2 hPa, 49.8 g of a colorless and transparent prepolymer was obtained. Next, 44.0 g of the obtained prepolymer and 190 mL of heptane were added to a 500 mL four-necked flask equipped with a stirrer, a temperature sensor, and a Dean-Stark trap, and heated under reflux for 1 hour. At this time, a small amount of water flowed out. Then, a solution prepared by dissolving about 40 mg of tin (II) 2-ethylhexanoate in about 1 mL of heptane was added to start the condensation reaction. When reacted at the reflux temperature for 110 minutes, about 1.9 to 2.4 mL of condensation reaction water was distilled. After 200 mL of ethanol and 200 mL of methanol were added to the reaction solution for liquid separation operation, it was left overnight. When the lower layer of the liquid separated into two layers was evaporated at 60 ° C. and 2 hPa, 35.3 g of a silicone resin having a colorless transparent oily polymerizable ethylenically unsaturated double bond in the molecule was obtained. When the upper layer was evaporated at 60 ° C. and 2 hPa, 8.1 g of a colorless liquid containing low molecular weight impurities was obtained. In addition, the following table shows the results of analysis of the charged amount, weight average molecular weight, refractive index, and viscosity.

(Comparative Example 2)
Silanol (82 to 86 mol%) dimethyl (14 to 18 mol%) diphenylsiloxane copolymer (both ends silanol (82 to 86 mol%) removed in advance by a thin-film distillation apparatus in a 1000 mL four-necked flask equipped with a reflux condenser, temperature sensor, Dean-Stark trap, and stirrer ( UCT PS-084) refined product 90.0 g, 3-acryloxypropyldimethoxymethylsilane (silanes (A) KBM-5102 manufactured by Shin-Etsu Chemical Co., Ltd.) 10.0 g and heptane 400 mL were charged to 101 ° C. with stirring. And refluxed for 30 minutes. A trace amount of water distills. A solution prepared by dissolving 33 mg of tin (II) 2-ethylhexanoate in about 1 mL of heptane was added to start the condensation reaction. When heated to reflux at 101 ° C. for 75 minutes, 0.7 g of water was distilled. Subsequently, 60 mL of trimethylmethoxysilane was slowly added from the upper part of the cooling pipe, and heating and refluxing were continued at 91 to 92 ° C. for 150 minutes. An additional 0.2 mL of water flowed into the Dean Stark trap. After cooling, 50 mL of heptane, 450 mL of ethanol, and 450 mL of methanol were added to carry out a liquid separation operation, and then left overnight. When the lower layer separated into two layers was evaporated at 60 ° C. and 2 hPa, 77.5 g of a colorless transparent oily silicone resin having a polymerizable ethylenically unsaturated double bond in the molecule was obtained. The weight average molecular weight Mw was 66600. Further, when the upper layer was evaporated at 60 ° C. and 2 hPa, 24.6 g of a colorless liquid was obtained.

Table 2

The molar ratio of the silanes (A) having an acrylic group represents the moles of the silanes (A) having an acrylic group when “silanes (B) + silanes (C) = 100 mol”.
In addition, the polymerizable ethylenically unsaturated double bond introduction ratio (%) is defined as the acrylic group in the silicone resin obtained with respect to the molar ratio of the silanes (A) having a charged acrylic group defined in Formula I. This represents the molar ratio of the siloxane units derived from the silanes (A).

Formula I

  On the other hand, the raw material PS-084 and the obtained silicone resin were subjected to 1H-NMR measurement to calculate the molar ratio of the charge and the molar ratio of the silicone resin. It is shown in the following table.

Table 3 Molar ratio of preparation and molar ratio of silicone resin by 1H-NMR

  In a 300 mL flask equipped with a stirrer and a condenser tube, 44.9 g of dimethoxydimethylsilane (silanes (B)), 21.1 g of diphenylsilanediol (silanes (C)), 3-acryloxypropyldimethoxymethylsilane (silanes) (A)) 3.8 g, 0.2 g of triethylamine as an organic amine catalyst, and 49.8 g of water were heated and stirred at 81 to 83 ° C. for 6 hours. When the obtained reaction product was evaporated at 60 ° C. and 2 hPa, 49.8 g of a colorless and transparent prepolymer was obtained. Next, 44.0 g of the obtained prepolymer and 190 mL of heptane were added to a 500 mL four-necked flask equipped with a stirrer, a temperature sensor, and a Dean-Stark trap, and heated under reflux for 1 hour. At this time, a small amount of water flowed out. Then, a solution prepared by dissolving about 40 mg of tin (II) 2-ethylhexanoate in about 1 mL of heptane was added to start the condensation reaction. When reacted at the reflux temperature for 110 minutes, about 1.9 to 2.4 mL of condensation reaction water was distilled. After 200 mL of ethanol and 200 mL of methanol were added to the reaction solution for liquid separation operation, it was left overnight. When the lower layer of the liquid separated into two layers was evaporated at 60 ° C. and 2 hPa, 35.3 g of a silicone resin having a colorless transparent oily polymerizable ethylenically unsaturated double bond in the molecule was obtained. When the upper layer was evaporated at 60 ° C. and 2 hPa, 8.1 g of a colorless liquid containing low molecular weight impurities was obtained. In addition, the following table shows the results of analysis of the charged amount, weight average molecular weight, refractive index, and viscosity.

The flask was made 44.9 g of dimethoxydimethylsilane (silanes (B)), 21.1 g of diphenylsilanediol (silanes (C)), and 11.4 g of 3-acryloxypropyldimethoxymethylsilane (silanes (A)). Except for the above, in the same manner as in Example 8, 56.3 g of a colorless and transparent prepolymer was obtained.
In the same manner as in Example 8 using 44.0 g of the obtained prepolymer, 25.0 g of a silicone resin having a colorless transparent oily polymerizable ethylenically unsaturated double bond in the molecule was obtained.

The flask was 44.9 g of dimethoxydimethylsilane (silanes (B)), 21.1 g of diphenylsilanediol (silanes (C)), and 34.3 g of 3-acryloxypropyldimethoxymethylsilane (silanes (A)). Except for the above, in the same manner as in Example 8, 74.9 g of a colorless and transparent prepolymer was obtained.
A condensation reaction was carried out using 44.0 g of the obtained prepolymer, and in the same manner as in Example 8, 22.9 g of a silicone resin having a colorless transparent oily polymerizable ethylenically unsaturated double bond in the molecule was obtained.

  In the flask, 41.6 g of dimethoxydimethylsilane (silanes (B)), 23.9 g of diphenylsilanediol (silanes (C)), and 3.6 g of 3-acryloxypropyldimethoxymethylsilane (silanes (A)) were used. Except for the above, in the same manner as in Example 8, 50.1 g of a colorless and transparent prepolymer was obtained. A condensation reaction was performed using 44.0 g of the obtained prepolymer, and in the same manner as in Example 8, 33.4 g of a silicone resin having a colorless transparent oily polymerizable ethylenically unsaturated double bond in the molecule was obtained.

  Dimethoxydimethylsilane (silanes (B)) 51.3 g, diphenylsilanediol (silanes (C)) 14.7 g, 3-acryloxypropyldimethoxymethylsilane (silanes (A)) 4.0 g were added to the flask. Except for the above, in the same manner as in Example 8, 48.2 g of a colorless and transparent prepolymer was obtained. A condensation reaction was performed using 44.0 g of the obtained prepolymer, and 35.8 g of a silicone resin having a colorless transparent oily polymerizable ethylenically unsaturated double bond in the molecule was obtained in the same manner as in Example 38.

  In the flask, 51.3 g of dimethoxydimethylsilane (silanes (B)), 14.7 g of diphenylsilanediol (silanes (C)), and 12.0 g of 3-acryloxypropyldimethoxymethylsilane (silanes (A)) were used. Except for the above, in the same manner as in Example 8, 54.7 g of a colorless and transparent prepolymer was obtained. A condensation reaction was carried out using 44.0 g of the obtained prepolymer, and in the same manner as in Example 8, 26.7 g of a colorless transparent oily silicone resin having a polymerizable ethylenically unsaturated double bond in the molecule was obtained.

Each silicone resin was applied onto a glass of 5 cm × 5 cm by a bar coater, and cured by irradiation with UV of F300S-12 (H plus bulb) as an ultraviolet light source using an apparatus manufactured by Fusion UV Systems Japan. The hardness of the cured product formed by this method was evaluated from the following viewpoints.
◎ The cured product has both elasticity and strength.
○ Hardened product has elasticity but poor strength.
X The cured product has poor elasticity and strength.

Table 4

Table 5

    From the comparison between Example 1 and Comparative Example 1, the amount of the water-soluble low molecular weight silane compound in the aqueous layer to be removed in the prepolymer synthesis obtained in the present invention can be reduced, and the product yield can be increased. This can also suppress the formation of nonflammable silicon dioxide during the treatment of the aqueous layer waste liquid.

  In Comparative Example 2, which is a conventional method, dialkoxydialkylsilanes (A) having a polymerizable ethylenically unsaturated double bond are introduced only about 50% with respect to the charged amount, whereas 65 to 90%. And the introduction rate has improved. In particular, in Examples 5 to 7, it is introduced with a high probability of exceeding 80% to 83 to 87%, which is remarkably excellent in that it can be efficiently manufactured. This is because the alkoxy group of the dialkoxydialkylsilane (A) having a polymerizable ethylenically unsaturated double bond is hydrolyzed and efficiently incorporated into the prepolymer in the prepolymerization step. I guess.

That is, in the method for producing a siloxane prepolymer of the present invention using a prepolymerization catalyst as an amine catalyst, a high-quality siloxane prepolymer can be obtained without impairing the optical properties of transparency and refractive index. The introduction of dialkylsiloxane groups having unsaturated double bonds can be increased. Silicone resin using this is excellent in optical characteristics.
Furthermore, in the production method, the neutralization step is not required, and water used for hydrolysis and alcohols generated by hydrolysis of the dialkoxydialkylsilanes (A) to (B) are used as well as amines. Since the catalyst can also be distilled off at a time, the process can be simplified, and it is excellent in that the discharge of silicon into wastewater can be reduced.

  Siloxane prepolymers having polymerizable ethylenically unsaturated double bonds in the molecule, when this is crosslinked and polymerized into a silicone resin, window glass, various flat display elements, alternatives to various liquid crystal display elements, optical shutters It can be suitably used for light control materials such as optical switches, advertisement and guidance display boards, glasses, and sunglasses.

Claims (8)

  Dialkoxydialkylsilanes (A) having a polymerizable ethylenically unsaturated double bond in the molecule, dialkoxydialkylsilanes (B), and diarylsilanediols (C) as starting materials, and organic amines A method for producing a siloxane prepolymer having a polymerizable ethylenically unsaturated double bond as a substituent in a molecule, wherein a condensation reaction is carried out as a catalyst, and the catalyst and / or by-product water is distilled off.   The method for producing a siloxane prepolymer having a polymerizable ethylenically unsaturated double bond in a molecule according to claim 1, wherein the organic amine is an aliphatic amine or an aromatic amine having a boiling point of 60 to 120 ° C.   A ratio of 0.5 to 30% of siloxane units introduced using dialkoxydialkylsilanes (A) having a polymerizable ethylenically unsaturated double bond as a starting material with respect to all units in one molecule of the siloxane prepolymer. A siloxane prepolymer having a polymerizable ethylenically unsaturated double bond in the molecule.   10-30% of siloxane units introduced starting from dialkoxydialkylsilanes (A) having a polymerizable ethylenically unsaturated double bond in the molecule are based on the total units in one molecule of the siloxane prepolymer. A siloxane prepolymer having a polymerizable ethylenically unsaturated double bond in the molecule, which is contained in a proportion.   5. The siloxane prepolymer having a polymerizable ethylenically unsaturated double bond in a molecule according to claim 3, wherein the polystyrene-reduced weight average molecular weight (Mw) is 1,000 or less.   The silicone resin which has a polymerizable ethylenically unsaturated double bond in a molecule | numerator obtained using the siloxane prepolymer which has the polymerizable ethylenically unsaturated double bond in any one of Claims 3-5 in a molecule | numerator.   The weight-average molecular weight (Mw) in terms of polystyrene is 10,000 to 100,000. The silicone resin having a polymerizable ethylenically unsaturated double bond in the molecule according to claim 6.   The weight average molecular weight (Mw) in terms of polystyrene is 50,000 to 100,000, The silicone resin having a polymerizable ethylenically unsaturated double bond in the molecule according to claim 6.