JP7748639B2 - Primer film, precursor solution for producing the primer film, substrate for forming silicone gel layer, silicone gel composite, and method for producing the same - Google Patents

Description

The present invention relates to a primer film capable of adhering a silicone gel layer containing a silicone resin and a silicone oil to a substrate surface with good adhesion, and a precursor solution for producing the primer film. It also relates to a substrate for forming a silicone gel layer having a primer film on the substrate, a silicone gel composite in which a silicone gel layer is formed on the substrate via a primer film, and a method for producing the silicone gel composite.

Organogel has been attracting attention as a surface treatment agent that can prevent droplets from adhering to the surface of a substrate.
An organogel is a gel in which an organic solvent is contained in a network structure formed by crosslinking polymers, and a typical example is a silicone gel produced by preparing a precursor solution using modified silicone with vinyl terminal groups, modified silicone with hydrosilyl groups, a catalyst, and an organic solvent compatible with these liquids as raw materials, dropping the solution onto the surface of any substrate, and then heating and curing the solution. In the above production method, the crosslinking reaction is carried out by a catalytic reaction between the vinyl terminal group of the modified silicone and the hydrosilyl group.

Non-Patent Document 1 describes that silicone gels produced by crosslinking polydimethylsiloxane in the presence of commercially available silicone oil have better ice adhesion resistance than silicone resins crosslinked without oil.

Patent Document 1 discloses a silicone gel that has excellent resistance to adhesion to water and oil and can spontaneously synerase due to temperature or chemical reaction (paragraphs [0006] and [0007]). The wet gel includes a crosslinked silicone resin formed by curing a silicone resin composition, a first liquid which may be a silicone oil capable of dissolving the silicone resin composition, and a second liquid which is miscible with the first liquid, and the first liquid may also serve as the second liquid (claims 1, 2, and 4).

Incidentally, when forming a silicone resin layer on a substrate, it is known that fixing a functional group that is chemically reactive with the hydrosilyl group in the modified silicone to the surface of the substrate is effective in improving adhesion to the substrate.
For example, Patent Document 2 attempts to improve the adhesion between a silicone resin and a substrate by using a vinyl siloxane oligomer as a primer, which is obtained by hydrolyzing and condensing a silane compound having a vinyl group alone.

Meanwhile, the inventors have already discovered that one type of coating with excellent adhesion to substrates is a transparent organic-inorganic hybrid coating obtained by applying a precursor liquid obtained by co-hydrolyzing and condensing an organosilane and a metal alkoxide in a solution containing an organic solvent, water, and a catalyst to the surface of a substrate and then leaving the precursor liquid to stand for a predetermined period of time at room temperature and atmospheric pressure. The organic-inorganic hybrid coating exhibits excellent adhesion to various substrates, including metals, metal oxide films, alloys, semiconductors, polymers, ceramics, glass, and resins (see Patent Document 3, Claim 1, paragraph [0001]; Patent Document 4, Claim 1, paragraph [0001]).

International Publication No. 2015/198985 JP 2010-261014 A JP 2013-213181 A JP 2013-249389 A

ACS Appl. Mater. Interfaces 2021, 13, 24, 28925-28937

Generally, in order for a surface treatment agent to fully exert its function, it needs to have good adhesion to the substrate.
The silicone gels disclosed in Non-Patent Document 1 and Patent Document 1 have difficulty in achieving high adhesion because they do not form chemical bonds with the substrate surface.
The technique disclosed in Patent Document 2 improves the adhesion between silicone resin and substrate. However, because the ratio of organic matter to Si, which is the crosslinking point of the primer itself, is inevitably high, there are drawbacks such as the primer not being hard enough and the primer being prone to swelling in organic solvents, making this primer unsuitable for bonding silicone gels whose surface treatment agents contain organic solvent components.
Patent Documents 3 and 4 disclose organic-inorganic hybrid coatings that have excellent adhesion to substrates, but do not suggest adhesion between silicone gel and substrates.

The inventors therefore undertook further research to provide a primer film that improves adhesion between the silicone gel layer and the substrate, and to provide a silicone gel composite with excellent adhesion.

The present invention proposes the following as a means for solving the above problems.
[1] A primer coating for forming a silicone gel layer on the surface of a substrate, the primer coating containing a crosslinked silicone resin having a hydrosilyl group as a backbone component and a silicone oil, the primer coating containing a co-hydrolysis/condensation polymerization product of an organosilane and a metal alkoxide , the organosilane being an organosilane having an unsaturated group represented by the following formula (1), and the metal alkoxide being a tetraalkoxysilane represented by the following formula (2):
CH ₂ =CH-R ¹ -Si-(OR ² ) ₃ ...(1)
(In the formula, ^R1 represents an alkylene group having 1 to 10 carbon atoms, and ^R2 represents alkyl groups having 1 to 4 carbon atoms, which may be the same or different.)
Si( ^OR3 ) ₄・・・・・・・・・・(2)
(In the formula, ^R3 represents an alkyl group having 1 to 4 carbon atoms, which may be the same or different.)
[2] A precursor solution for producing the primer coating of (1) above, comprising an organic solvent, water, a sol-gel catalyst, an organosilane, and a metal alkoxide, wherein the organosilane is an organosilane containing an unsaturated group represented by the above formula (1),
The precursor solution wherein the metal alkoxide is a tetraalkoxysilane represented by the above formula (2).
[3] A substrate for forming a silicone gel layer containing a crosslinked silicone resin having a hydrosilyl group as a backbone component and a silicone oil, the substrate comprising a base material and a primer coating formed on the surface of the base material, the primer coating containing a co-hydrolysis/condensation polymerization product of an organosilane and a metal alkoxide , the organosilane being an organosilane having an unsaturated group represented by the above formula (1), and the metal alkoxide being a tetraalkoxysilane represented by the above formula (2).
[4] A silicone gel composite comprising a substrate, a primer coating formed on the surface of the substrate, and a silicone gel layer formed via the primer coating, the silicone gel layer containing a crosslinked silicone resin containing hydrosilyl groups as a skeleton component and a silicone oil, wherein the primer coating contains a co-hydrolysis/condensation polymerization product of an organosilane and a metal alkoxide , the organosilane being an organosilane containing an unsaturated group represented by the above formula (1), and the metal alkoxide being a tetraalkoxysilane represented by the above formula (2).
[5] A method for producing the silicone gel composite of [4] above, comprising the steps of: applying a precursor solution containing an organic solvent, water, a sol-gel catalyst, an organosilane having an unsaturated group represented by formula (1) above, and a metal alkoxide represented by formula (2) above onto a substrate, and forming a primer film by a sol-gel method; and dropping a silicone gel raw material, which is a mixture of a silicone resin raw material containing a compound having a vinyl group and a compound having a hydrosilyl group , with silicone oil onto the primer film, and curing the mixture to form a silicone gel layer in which a crosslinked silicone resin having a hydrosilyl group, which is a skeleton component, is impregnated with silicone oil.

The present invention provides a primer coating that improves adhesion between the silicone gel layer and the substrate, making it possible to provide a silicone gel composite with excellent adhesion.

1 is a diagram schematically illustrating a method for producing a primer film according to the present embodiment and its action and mechanism. FIG. 1 is a diagram schematically illustrating the low adhesion property of the silicone gel according to the present embodiment. Photographs illustrating the steps of an embodiment of the present invention

A first aspect of the present invention is a primer coating for forming a silicone gel layer on a substrate surface, the primer coating comprising a crosslinked silicone resin having hydrosilyl groups as a backbone component and a silicone oil, the primer coating comprising a co-hydrolysis/condensation polymerization product of an organosilane and a metal alkoxide , the organosilane being an organosilane having an unsaturated group represented by the following formula (1), and the metal alkoxide being a tetraalkoxysilane represented by the following formula (2):
CH ₂ =CH-R ¹ -Si-(OR ² ) ₃ ...(1)
(In the formula, ^R1 represents an alkylene group having 1 to 10 carbon atoms, and ^R2 represents alkyl groups having 1 to 4 carbon atoms, which may be the same or different.)
Si( ^OR3 ) ₄・・・・・・・・・・(2)
(In the formula, ^R3 represents an alkyl group having 1 to 4 carbon atoms, which may be the same or different.)

A second aspect of the present invention is a precursor solution for producing the primer coating, comprising an organic solvent, water, a sol-gel catalyst, an organosilane, and a metal alkoxide, wherein the organosilane is an organosilane containing an unsaturated group represented by formula (1) above, and the metal alkoxide is a tetraalkoxysilane represented by formula (2) above.

A third aspect of the present invention is a substrate for forming a silicone gel layer containing a crosslinked silicone resin containing hydrosilyl groups as a backbone component and a silicone oil, the substrate comprising a base material and a primer coating formed on the surface of the base material, the primer coating containing a co-hydrolysis/condensation polymerization product of an organosilane and a metal alkoxide , the organosilane being an organosilane containing an unsaturated group represented by formula (1) above, and the metal alkoxide being a tetraalkoxysilane represented by formula (2) above.

A fourth aspect of the present invention is a silicone gel composite comprising a substrate, a primer coating formed on the surface of the substrate, and a silicone gel layer formed via the primer coating, the silicone gel layer containing a crosslinked silicone resin containing hydrosilyl groups as a skeleton component and a silicone oil, wherein the primer coating contains a co-hydrolysis/condensation polymerization product of an organosilane and a metal alkoxide , the organosilane being an organosilane containing an unsaturated group represented by formula (I) above, and the metal alkoxide being a tetraalkoxysilane represented by formula (2) above.

A fifth aspect of the present invention is a method for producing a composite comprising a substrate, a primer layer formed on the surface of the substrate, and a silicone gel layer formed via the primer layer, the silicone gel layer being composed of a silicone resin and a silicone oil, the method comprising the steps of: applying a precursor solution containing an organic solvent, water, a sol-gel catalyst, an organosilane having an unsaturated group represented by formula (1) above, and a metal alkoxide represented by formula (2) above onto the substrate, and curing the solution by a sol-gel method to form a primer layer; and dropping a silicone gel raw material, which is a mixture of a crosslinked silicone resin raw material containing a compound having a vinyl group and a compound having a hydrosilyl group , and silicone oil onto the primer layer and curing the mixture, to form a silicone gel layer in which the silicone oil is impregnated into a crosslinked silicone resin, which is a skeleton component and contains hydrosilyl groups .
The sol-gel method is a reaction in which the alkoxy groups of a metal alkoxide are hydrolyzed in a solution, and the resulting intermediate undergoes a spontaneous condensation polymerization reaction to form a solid, and the sol-gel catalyst is a catalyst for accelerating the above reaction.

In light of the above aspects, the present invention provides a primer film that has excellent adhesion to a substrate, a precursor solution for producing the primer film, a substrate for forming a silicone gel layer having a primer film on the substrate, a silicone gel composite having a primer film and a silicone gel layer on the substrate, and a method for producing the silicone gel composite.

In this specification, when a numerical range is expressed using "~", it includes both ends of the range.

Below, we will explain each aspect of the present invention in more specific embodiments (hereinafter referred to as "present embodiments"), including the best mode thereof.

[Primer coating]
The primer coating according to this embodiment contains, as a raw material composition, an organosilane represented by the following formula (1) and a tetraalkoxysilane represented by the following formula (2).
CH ₂ =CH-R ¹ -Si-(OR ² ) ₃ ...(1)
(In the formula, ^R1 represents an alkylene group having 1 to 10 carbon atoms, and ^R2 represents alkyl groups having 1 to 4 carbon atoms, which may be the same or different.)
Si( ^OR3 ) ₄・・・・・・・・・・(2)
(In the formula, ^R3 represents an alkyl group having 1 to 4 carbon atoms, which may be the same or different.)
The above-mentioned raw material composition undergoes the co-hydrolysis and condensation polymerization reactions described below to produce a primer coating having a polysiloxane skeleton with unsaturated groups bonded to some of the silicon atoms, as described in further detail below.

(organosilane)
The reason why R ¹ of the organosilane in formula (1) is an alkylene group having 1 to 10 carbon atoms is that the larger the number of carbon atoms in the alkylene chain between Si and the terminal vinyl group (unsaturated group), the more likely it is that a primer coating with excellent adhesion to the silicone gel will be obtained.
Explaining this with reference to FIG. 1, in FIG. 1, a vinyl group is shown schematically as a partially cut-out circle, and a hydrosilyl group is shown as a circle formed by complementary bonding with the vinyl group.
It is presumed that when the alkylene chain of ^R1 has one or more carbon atoms, the probability of the vinyl group being exposed from the polysiloxane skeleton of the primer coating increases, and therefore the proportion of the vinyl group bonding with the hydrosilyl group contained in the skeleton component of the silicone gel increases. Note that, from the viewpoint of the production cost of the organosilane, the number of carbon atoms in ^R1 is set to 10 or less.

Furthermore, the reason why R ² of the organic silane in formula (1) is an alkyl group having 1 to 4 carbon atoms, which may be the same or different, is that the alkoxy group (OR ² ) is a group that contributes to the cohydrolysis and condensation polymerization reaction when forming the polysiloxane skeleton, and the shorter the group, the faster the hydrolysis rate and the easier it is for the leaving group to volatilize during film formation and therefore is less likely to remain in the film.

Specific examples of organic silanes that can be used include allyltrimethoxysilane, allyltriethoxysilane, allyldiethoxymethoxysilane, 7-octenyltrimethoxysilane, 7-octenyltriethoxysilane, and 7-octenyldiethoxymethoxysilane.

(Tetraalkoxysilane)
^OR3 , which is the alkoxy group of the tetraalkoxysilane represented by formula (2), is also a group that contributes to the cohydrolysis and condensation polymerization reaction when forming the polysiloxane skeleton. The reason why ^R3 is an alkyl group having 1 to 4 carbon atoms, which may be the same or different, is that the shorter the alkyl group, the faster the hydrolysis rate, and the easier it is for the leaving group to volatilize during film formation, making it less likely for the leaving group to remain in the film.
Specific examples of the tetraalkoxysilane include tetramethoxysilane, tetraethoxysilane, ethoxytrimethoxysilane, tetra-n-propoxysilane, tetra-i-propoxysilane, tetra-n-butoxysilane, and tetra-t-butoxysilane.

[Method of manufacturing primer film]
The primer coating according to this embodiment can be formed as an organic-inorganic hybrid coating having a polysiloxane skeleton and in which unsaturated groups derived from the organosilane are exposed on the surface of the substrate, by applying a precursor solution containing an organosilane and a tetraalkoxysilane (described below) to a substrate and then co-hydrolyzing and condensing the solution.
Because this primer coating is an organic-inorganic hybrid film, it can improve adhesion to the substrate regardless of whether the substrate is made of an organic or inorganic material, and by strengthening the bond between the unsaturated groups and the silicone resin skeleton of the silicone gel formed in the upper layer, it can also improve adhesion between the substrate and the silicone gel.

[Precursor solution]
As shown in the left part of FIG. 1, the precursor solution according to this embodiment is prepared by adding an organic solvent, water, and a sol-gel catalyst to organosilane and tetraalkoxysilane, which are raw materials for the primer film.
The organic solvent is preferably one that is miscible with a small amount of water to form a transparent and uniform coating, can dissolve the polycondensed product of organosilane and metal alkoxide, and quickly volatilizes when the precursor solution is applied to the substrate, i.e., one with a vapor pressure higher than that of water, such as methanol, ethanol, isopropanol, or tetrahydrofuran.

The amount of water added is preferably equal to or greater than the number of moles of functional groups mentioned above, so that all reactive functional groups contained in the precursor solution are hydrolyzed to generate Si-OH groups. A film can still be formed even if the amount of water is less than the above number of moles. However, in order to improve yield by performing sufficient hydrolysis without volatilizing the organosilane and metal alkoxide during processing, it is preferable to include an amount of water equal to or greater than the number of moles of functional groups mentioned above.

In the precursor solution according to this embodiment, a sol-gel catalyst having the effect of promoting hydrolysis of the alkoxy group is used in order to promote hydrolysis of the reactive functional groups (alkoxy groups) of the organosilane and metal alkoxide (to generate Si—OH groups).
For example, when a condensation polymer of an organic silane and a metal alkoxide is stabilized at a pH of 1 to 3, it is preferable to use an organic acid such as hydrochloric acid or p-toluenesulfonic acid.

The sol-gel reaction of the precursor solution can be carried out by heating. Heating conditions are, for example, 25 to 80°C and 1 to 24 hours. The reaction can also be induced by applying energy other than heat.

[Silicone gel]
FIG. 2 shows a schematic diagram of the structure of the silicone gel according to this embodiment.
An organogel that exhibits anti-adhesion properties contains a crosslinked resin framework component that is immiscible with the substance to be liquid-repellent, and a liquid component that is immiscible with the substance but miscible with the framework component and is difficult to volatilize. This structure controls the movement of the liquid component inside and outside the gel, enabling the liquid component to synerase.
In the case of the silicone gel according to this embodiment, the backbone component is a cross-linked silicone resin, and the liquid component is silicone oil, making it difficult for water-based and oil-based substances to adhere to it.
The silicone gel can be produced by mixing a silicone resin raw material containing a compound having a vinyl group and a compound having a hydrosilyl group with silicone oil, and inducing a hydrosilylation reaction of the silicone resin raw material, resulting in a structure in which the crosslinked silicone resin, which is the skeleton component, is impregnated with silicone oil, as shown in Figure 2. This will be described in detail below.

(Silicone resin raw material)

Compounds having a vinyl group include, but are not limited to, silicone resins having a vinyl group, metal alkoxides having a vinyl group, etc.

Examples of silicone resins containing vinyl groups include modified polydimethylsiloxane and polymethylvinylsiloxane, which have vinyl groups introduced at both ends.

Examples of metal alkoxides having a vinyl group include vinyltriethoxysilane and allyltriethoxysilane.

Compounds having a hydrosilyl group include, but are not limited to, silicone resins having a hydrosilyl group, metal alkoxides having a hydrosilyl group, etc.

Examples of silicone resins containing hydrosilyl groups include dimethylmethylhydrogenpolysiloxane.

Examples of metal alkoxides having a hydrosilyl group include triethoxysilane and trimethoxysilane.
An example of a commercially available silicone resin raw material is Sylgard 184 manufactured by Dow Corning.

(silicone oil)
The silicone oil is not particularly limited as long as it can be mixed with the silicone resin, and examples thereof include polymethylphenylsiloxane and phenylmethylsiloxane-dimethylsiloxane copolymer.

(Hydrosilylation Reaction)
When the silicone resin raw material is cured by a hydrosilylation reaction, a platinum-based catalyst may be used.

The platinum catalyst is not particularly limited, but examples thereof include Karsted's catalyst (Pt ₂ [(Me ₂ SiCH═CH 2 ) ₂ O] ₃ ), H ₂ PtCl _6, and the like.

The silicone resin raw material may be heated to harden.

The temperature at which the silicone resin raw material is cured can be adjusted as needed depending on the amount of catalyst added, but is typically between 20 and 150°C.

[Base material]
The substrate usable in this embodiment may be any suitable material, such as a metal, a metal oxide film, an alloy, a semiconductor, a polymer, a ceramic, glass, a resin, wood, paper, fiber, etc. Specific examples of suitable substrates include copper, brass, silicon, polyethylene terephthalate resin, polycarbonate resin, acrylic resin, silicone resin, ABS resin, glass, and wood, and resins such as polyethylene terephthalate resin, polycarbonate resin, acrylic resin, silicone resin, and ABS resin can be particularly used.
The substrate may have any shape, such as a plate, a concave-convex shape, a powder shape, a tube shape, a porous shape, or a fiber shape.
In the present invention, no particular pretreatment of the substrate is required, but it is also possible to use the substrate after cleaning/activating the surface with plasma, UV, or the like.
Furthermore, after an optional easy-adhesion layer is formed on the substrate, a primer coating may be formed.

Next, the present invention will be described in detail based on examples. Figure 3 shows an overview of the process. Note that the following examples are preferred examples of the present invention, and the present invention is not limited to these examples in any way.

Example 1
40.0 mL of ethanol, 14.0 mL of tetraethoxysilane, and 1.4 mL of allyltriethoxysilane were mixed, and 10.0 mL of 0.01 M hydrochloric acid was added. The mixture was stirred for 24 hours to prepare a primer precursor solution. The primer precursor solution was dripped onto a glass plate and heated at 80°C for 3 hours to form a primer film. The resulting primer film had a thickness of 500 nm. A silicone gel material, prepared by mixing a silicone resin material (Sylgard 184 manufactured by Dow Corning) with silicone oil (TSF431 manufactured by Momentive Performance Materials), was then dripped onto the surface of the primer film and cured at 80°C for 3 hours to produce a composite in which the glass plate and silicone gel layer were adhered via the primer film. The composite was immersed in hexane for 24 hours to evaluate adhesion, and no peeling occurred, and the adhesion was maintained.

(Examples 2 to 4)
A primer film was prepared in the same manner as in Example 1, except that 2.8 mL (Example 2), 5.6 mL (Example 3), or 11.2 mL (Example 4) of allyltriethoxysilane was mixed. Thereafter, a composite in which a glass plate and a silicone gel layer were adhered to each other via the primer film was prepared in the same manner as in Example 1.
The adhesion of the composite was evaluated, and all of Examples 2 to 4 were found to be as good as Example 1.

(Reference example)
A composite in which the primer film and silicone resin were adhered was prepared in the same manner as in Example 1, except that a silicone resin raw material (Sylgard 184 manufactured by Dow Corning) was dropped onto the surface of the primer film, and the adhesion and anti-adhesion properties of the composite were evaluated. The adhesion between the silicone resin and the primer film was as good as in Example 1, but as described in Non-Patent Document 1, when mayonnaise or ketchup was dropped onto the silicone resin surface as contaminants and the silicone resin was tilted, these contaminants remained on the silicone resin surface, and the anti-adhesion properties of the silicone resin were not as good as those of the silicone gel of Example 1.

(Comparative Example 1)
A composite consisting of a glass plate and a silicone gel layer was prepared in the same manner as in Example 1, except that no primer coating was formed.
When the composite was immersed in hexane for 24 hours, the silicone gel layer peeled off.

The present invention allows a silicone gel layer with excellent adhesion resistance to be applied in close contact with a substrate, making it possible to provide articles with surfaces that are excellent in water repellency, oil repellency, and stain resistance, such as food packaging and architectural structures.

Claims (7)

A primer coating for forming a silicone gel layer on a substrate surface, the silicone gel layer containing a crosslinked silicone resin having a hydrosilyl group as a backbone component and a silicone oil,
Contains a co-hydrolysis/condensation polymer of organic silane and metal alkoxide ,
The organosilane is an organosilane containing an unsaturated group represented by the following formula (1):
The primer coating, wherein the metal alkoxide is a tetraalkoxysilane represented by the following formula (2):
CH ₂ =CH-R ¹ -Si-(OR ² ) ₃ ...(1)
(In the formula, ^R1 represents an alkylene group having 1 to 10 carbon atoms, and ^R2 represents alkyl groups having 1 to 4 carbon atoms, which may be the same or different.)
Si( ^OR3 ) ₄・・・・・・・・・・(2)
(In the formula, ^R3 represents an alkyl group having 1 to 4 carbon atoms, which may be the same or different.) A precursor solution for producing the primer coating of claim 1, comprising:
comprising an organic solvent, water, a sol-gel catalyst, an organosilane, and a metal alkoxide;
The organosilane is an organosilane containing an unsaturated group represented by the following formula (1):
The precursor solution, wherein the metal alkoxide is a tetraalkoxysilane represented by the following formula (2):
CH ₂ =CH-R ¹ -Si-(OR ² ) ₃ ...(1)
(In the formula, ^R1 represents an alkylene group having 1 to 10 carbon atoms, and ^R2 represents alkyl groups having 1 to 4 carbon atoms, which may be the same or different.)
Si( ^OR3 ) ₄・・・・・・・・・・(2)
(In the formula, ^R3 represents an alkyl group having 1 to 4 carbon atoms, which may be the same or different.) A substrate for forming a silicone gel layer , which contains a crosslinked silicone resin having a hydrosilyl group as a skeleton component and a silicone oil,
A substrate and a primer coating formed on a surface of the substrate,
the primer coating contains a co-hydrolysis/condensation polymer of an organic silane and a metal alkoxide ;
The organosilane is an organosilane containing an unsaturated group represented by the following formula (1):
The substrate for forming a silicone gel layer, wherein the metal alkoxide is a tetraalkoxysilane represented by the following formula (2):
CH ₂ =CH-R ¹ -Si-(OR ² ) ₃ ...(1)
(In the formula, ^R1 represents an alkylene group having 1 to 10 carbon atoms, and ^R2 represents alkyl groups having 1 to 4 carbon atoms, which may be the same or different.)
Si( ^OR3 ) ₄・・・・・・・・・・(2)
(In the formula, ^R3 represents an alkyl group having 1 to 4 carbon atoms, which may be the same or different.) The substrate for forming a silicone gel layer according to claim 3, characterized in that the thickness of the primer coating is 10 to 10,000 nm. The substrate for forming a silicone gel layer according to claim 3 or 4, wherein the substrate is selected from the group consisting of glass, metal, and resin. A silicone gel composite comprising a substrate, a primer coating formed on the surface of the substrate, and a silicone gel layer formed via the primer coating, the silicone gel layer containing a crosslinked silicone resin having a hydrosilyl group as a skeleton component and a silicone oil,
the primer coating contains a co-hydrolysis/condensation polymer of an organic silane and a metal alkoxide ;
The organosilane is an organosilane containing an unsaturated group represented by the following formula (1):
The silicone gel composite, wherein the metal alkoxide is a tetraalkoxysilane represented by the following formula (2):
CH ₂ =CH-R ¹ -Si-(OR ² ) ₃ ...(1)
(In the formula, ^R1 represents an alkylene group having 1 to 10 carbon atoms, and ^R2 represents alkyl groups having 1 to 4 carbon atoms, which may be the same or different.)
Si( ^OR3 ) ₄・・・・・・・・・・(2)
(In the formula, ^R3 represents an alkyl group having 1 to 4 carbon atoms, which may be the same or different.) 7. The method for producing a silicone gel composite according to claim 6,
a step of applying a precursor solution containing an organic solvent, water, a sol-gel catalyst, an organosilane having an unsaturated group represented by the following formula (1), and a metal alkoxide represented by the following formula (2) onto a substrate, and forming a primer coating by a sol-gel method;
A method for producing a silicone gel composite includes a step of dropping a silicone gel raw material, which is a mixture of a silicone resin raw material containing a compound having a vinyl group and a compound having a hydrosilyl group and a silicone oil, onto the primer coating, and curing the mixture to form a silicone gel layer in which a crosslinked silicone resin, which is a skeleton component and contains a hydrosilyl group , is impregnated with the silicone oil.
CH ₂ =CH-R ¹ -Si-(OR ² ) ₃ ...(1)
(In the formula, ^R1 represents an alkylene group having 1 to 10 carbon atoms, and ^R2 represents alkyl groups having 1 to 4 carbon atoms, which may be the same or different.)
Si( ^OR3 ) ₄・・・・・・・・・・(2)
(In the formula, ^R3 represents an alkyl group having 1 to 4 carbon atoms, which may be the same or different.)