JP7193814B1 - One-component water-curing adhesive - Google Patents

Abstract

[Problem] To provide a silicone adhesive that can be easily applied in water, exhibits excellent curability even in water, exhibits excellent adhesiveness to adherends such as rocks and structures in water, and has excellent workability. provide. (A) 100 parts by mass of a silicone polymer having a plurality of alkoxy groups having 1 to 6 carbon atoms directly bonded to silicon atoms; (B) 200 to 800 parts by mass of a hydrophilic inorganic filler; and (C) A one-component water-curable adhesive containing 0.1-10 parts by mass of a curing catalyst, wherein the silicone polymer has an alkoxy group content of 20-40% by mass. [Selection figure] None

Description

The present disclosure relates to a one-part water-curable adhesive.

Reaction-curing adhesives are used in a wide range of applications because they do not contain solvents and have strong adhesive strength. However, when the adherend to be adhered is placed in water and its surface is wet, a water layer intervenes between the adhesive and the adherend and acts as a release agent, so the adherend adhesion is often not established between the adhesive and the adhesive.

Patent Document 1 (International Publication No. 2015/029615) describes an organic polymer composed of a water-soluble polymer unit forming a main chain, and a hydrophilic organic group and a self-assembling group bonded to the water-soluble polymer unit. An adhesive that cures in water or in a moist environment and exhibits adhesive properties is described, characterized by comprising a coalescing agent and a curing agent.

WO2015/029615

As for the adhesive described in Patent Document 1, it is difficult to obtain raw materials thereof, and the hydrophilic organic polymer may swell with water, which may reduce the strength of the adhesive.

Some two-part epoxy adhesives, which are widely used as reaction-curing adhesives, can be used in water, but they take a long time to cure and generally require heating for complete curing. In order to cure an epoxy adhesive at room temperature, it is necessary to add and mix a curing agent to a main agent containing an epoxy resin immediately before use, and then apply the mixture within the pot life. Therefore, when an epoxy-based adhesive is used for construction in water, work restrictions may occur.

One-part room temperature curing silicone adhesives exhibit good adhesion in air. However, since the adhesive has high water repellency, when it is used to bond an adherend in water, such as a rock or a concrete structure, a thin film of water tends to remain between the adhesive and the adherend. Adhesion is difficult to establish because the thin film acts as a mold release agent.

As described above, there is a need for an adhesive that cures in water, has sufficient strength and adhesion, is easy to work with, and can be prepared using readily available raw materials.

The present disclosure is a silicone adhesive that can be easily applied in water, exhibits excellent curability even in water, exhibits excellent adhesiveness to adherends such as underwater rocks and structures, and has excellent workability. intended to provide

As a result of intensive research by the present inventors to solve the above problems, a composition obtained by blending a silicone polymer having a plurality of lower alkoxy groups directly bonded to a silicon atom with a hydrophilic inorganic filler and a curing catalyst, It has been found that it cures well in water and adheres well to adherends such as rocks and structures in water.

The present invention includes the following aspects.
[Aspect 1]
(A) 100 parts by mass of a silicone polymer having a plurality of alkoxy groups having 1 to 6 carbon atoms directly bonded to silicon atoms;
(B) 200 to 800 parts by mass of a hydrophilic inorganic filler;
(C) A one-component water-curable adhesive containing 0.1 to 10 parts by mass of a curing catalyst, wherein the silicone polymer has an alkoxy group content of 20% to 40% by mass. mold glue.
[Aspect 2]
(A) 100 parts by mass of a silicone polymer having a plurality of alkoxy groups having 1 to 6 carbon atoms directly bonded to silicon atoms;
(B) 200 to 800 parts by mass of a hydrophilic inorganic filler;
(C) 0.1 to 10 parts by mass of a curing catalyst;
(D) A one-component water-curable adhesive containing 40 to 1000 parts by mass of a nonpolar organic polymer compound, wherein the silicone polymer has an alkoxy group content of 20% to 50% by mass. Underwater curing adhesive.
[Aspect 3]
The one-component water-curable adhesive according to aspect 2, wherein the non-polar organic polymer compound comprises a linear organopolysiloxane.
[Aspect 4]
The silicone polymer has the formula (1)
(SiO _4/2 ) _a (R ¹ SiO _3/2 ) _b (R ¹ ₂ SiO _2/2 ) _c (R ² O _1/2 ) _d (1)
(In formula (1), R ¹ each independently represents a methyl group or a phenyl group, R ² each independently represents a hydrogen atom, a methyl group, or an ethyl group, a, b, and c are 0 ≦a≦1, 0≦b≦1, 0≦c<0.5 and a+b+c=1, and d is a number satisfying 0<d<4).
4. The one-component water-curable adhesive according to any one of aspects 1 to 3, comprising a partially hydrolyzed condensate of a polyfunctional alkoxysilane represented by:
[Aspect 5]
Any one of aspects 1 to 4, wherein the hydrophilic inorganic filler contains at least one selected from the group consisting of fused spherical silica, deflagration spherical silica, and calcium carbonate particles, which are not surface-hydrophobicized. 1. The one-liquid water-curable adhesive described in .
[Aspect 6]
The one-component water-curable adhesive according to any one of aspects 1 to 5, wherein the hydrophilic inorganic filler has an average particle size of 0.1 μm to 50 μm.
[Aspect 7]
The one-component water-curable adhesive according to any one of aspects 1 to 6, wherein the curing catalyst is at least one selected from the group consisting of titanium alkoxide compounds and titanium chelate compounds.
[Aspect 8]
(E) The one-component water-curable adhesive according to any one of aspects 1 to 7, further comprising a polyfunctional alkoxysilane.
[Aspect 9]
The one-component water-curable adhesive according to aspect 8, wherein the polyfunctional alkoxysilane is at least one selected from the group consisting of tetraethoxysilane and vinyltrimethoxysilane.
[Aspect 10]
The one-component water-curable adhesive according to aspect 8 or 9, containing 1 to 20 parts by mass of the polyfunctional alkoxysilane.

Since the silicone-based adhesive of the present disclosure is a one-component water curing type, unlike a two-component curing type adhesive, it can be easily applied in water without the need to measure and mix the main agent and the curing agent at the time of use. be able to. In addition, the silicone-based adhesive of the present disclosure exhibits excellent curability even in water and excellent adhesiveness to adherends with wet surfaces such as rocks and structures in water. Therefore, it is possible to easily adhere inorganic materials such as metals and ceramics to adherends such as rocks and structures on the bottom of a river or in the sea by diving.

The above description should not be considered to disclose all embodiments of the invention or all advantages associated with the invention.

The present invention is described in more detail below for the purpose of illustrating representative embodiments of the invention, but the invention is not limited to these embodiments.

[One-liquid water-curable adhesive of the first embodiment]
The one-component water-curable adhesive of the first embodiment comprises (A) 100 parts by mass of a silicone polymer having a plurality of alkoxy groups having 1 to 6 carbon atoms directly bonded to silicon atoms, and (B) a hydrophilic inorganic filler. 200 to 800 parts by weight, (C) 0.1 to 10 parts by weight of a curing catalyst, and the alkoxy group content of the silicone polymer is 20% to 40% by weight.

The one-component water-curable adhesive of the first embodiment may further contain (D) a nonpolar organic polymer compound and (E) a polyfunctional alkoxysilane as optional components.

[One-liquid water-curable adhesive of the second embodiment]
The one-component water-curable adhesive of the second embodiment comprises (A) 100 parts by mass of a silicone polymer having a plurality of alkoxy groups having 1 to 6 carbon atoms directly bonded to silicon atoms, and (B) a hydrophilic inorganic filler. 200 to 800 parts by mass, (C) 0.1 to 10 parts by mass of a curing catalyst, and (D) 40 to 1000 parts by mass of a nonpolar organic polymer compound, and the alkoxy group content of the silicone polymer is 20% by mass. ~50% by mass.

The one-component water-curable adhesive of the second embodiment may further contain (E) a polyfunctional alkoxysilane as an optional component.

In general, inorganic fillers used in combination with silicone polymers are those whose surface has been hydrophobized using hexamethyldisilazane, dimethyldichlorosilane, higher alkyltrialkoxysilane, or higher fatty acid as a hydrophobizing agent. It has been known. The surface hydrophobizing treatment may also be carried out in-situ by mixing the silicone polymer with the hydrophobizing agent and adding the untreated inorganic filler to the mixture. It is well known that the addition of inorganic fillers to common silicone polymers without surface hydrophobizing treatment can lead to excessively high viscosity of the composition. On the other hand, a composition obtained by mixing a surface-hydrophobicized inorganic filler with a silicone polymer generally has water repellency. When such a composition having water repellency is used as an adhesive for an adherend in water, such as a rock or concrete structure, a thin film of water tends to remain between the adhesive and the adherend, and the water Adhesion is difficult to establish because the thin film acts as a mold release agent.

According to the present disclosure, by combining a hydrophilic inorganic filler with a relatively highly polar silicone polymer having a plurality of alkoxy groups, unexpectedly, while suppressing thickening of the composition, excellent Curability and excellent adhesion to adherends such as underwater rocks and structures can be obtained.

<(A) Silicone polymer having a plurality of alkoxy groups having 1 to 6 carbon atoms directly bonded to a silicon atom>
(A) A silicone polymer having a plurality of alkoxy groups having 1 to 6 carbon atoms directly bonded to a silicon atom (hereinafter simply referred to as "silicone polymer") is, for example, commonly used as a component of room-temperature-curable silicone rubber compositions. A linear dimethylpolysiloxane having multiple alkoxy groups with 1 to 6 carbon atoms at both ends, and an alkoxy group with 1 to 6 carbon atoms, which is widely used as a component of moisture-curable hard coating agents. Partially hydrolyzed condensates of silane compounds having a plurality of Examples of alkoxy groups having 1 to 6 carbon atoms include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, and n-hexanoxy groups. From the viewpoint of curability and adhesiveness, the alkoxy group having 1 to 6 carbon atoms is preferably a methoxy group or an ethoxy group. A silicone polymer can be used individually or in combination of 2 or more types from which a composition differs.

The silicone polymer preferably contains a partial hydrolysis condensate of a silane compound having a plurality of alkoxy groups having 1 to 6 carbon atoms, represented by formula (1)
(SiO _4/2 ) _a (R ¹ SiO _3/2 ) _b (R ¹ ₂ SiO _2/2 ) _c (R ² O _1/2 ) _d (1)
(In formula (1), R ¹ each independently represents a methyl group or a phenyl group, R ² each independently represents a hydrogen atom, a methyl group, or an ethyl group, a, b, and c are 0 ≤ a ≤ 1, 0 ≤ b ≤ 1, 0 ≤ c < 0.5, a number satisfying a + b + c = 1, and d satisfying 0 < d < 4)
It is more preferable to contain a partially hydrolyzed condensate of a polyfunctional alkoxysilane represented by (hereinafter also referred to as "alkoxy oligomer").

From the viewpoint of alkoxy group content, that is, reaction activity, the ratio of phenyl groups to the total number of R ¹ in formula (1) is preferably 0% to 10%.

From the viewpoint of reactivity, the total ratio of methyl groups and ethyl groups to the total number of R ² in formula (1) is preferably 80% to 100%.

From the viewpoint of availability of the alkoxy oligomer, it is preferable that a=0 or a=1.

When a=1, then b=0 and c=0, and such alkoxy oligomers are also referred to as "Q oligomers" in this disclosure.

When a = 0, from the viewpoint of alkoxy group content, that is, reaction activity, it is preferable that 0.5 ≤ b ≤ 1, 0 ≤ c ≤ 0.5, and 0.7 < d ≤ 3. .0 is preferred.

The weight average molecular weight (Mw) of the alkoxy oligomer is preferably 200 to 3,000 in terms of standard polystyrene in gel permeation chromatography (GPC).

The properties of the alkoxy oligomer are determined by the factors of formula (1), ie, the values of a, b, c, and d, the ratio of methyl and phenyl groups in ^R1 , and the like. The structure of an alkoxy oligomer is generally estimated from viscosity, specific gravity, refractive index, and alkoxy group content. For example, viscosity correlates with the molecular weight of the alkoxy oligomer. The ratio of methyl and phenyl groups in ^R1 can be estimated from the refractive index, and the higher the refractive index, the higher the ratio of phenyl groups. The alkoxy group content is related to the ratio of b to c, viscosity and phenyl group content.

The kinematic viscosity of the alkoxy oligomer is preferably 2-200 mm ² /s. Kinematic viscosity is a value measured at 25° C. using a Canon-Fenske viscometer in accordance with JIS Z 8803:2011.

The specific gravity of the alkoxy oligomer is preferably 1.04-1.20 at 25°C.

The refractive index of the alkoxy oligomer is preferably between 1.392 and 1.512 at 25°C.

In the first embodiment, the alkoxy group content of the alkoxy oligomer is preferably 22% by mass to 36% by mass, more preferably 24% by mass to 34% by mass.

In the second embodiment, the alkoxy group content of the alkoxy oligomer is preferably 30% to 55% by mass, more preferably 35% to 50% by mass.

The alkoxy oligomer can be produced according to a known method for producing organopolysiloxane, and can be obtained, for example, by hydrolytically condensing a silane compound having a hydrolyzable group. The silane compound having a hydrolyzable group is a silane compound that has 1 to 4 chlorine atoms or alkoxy groups that are hydrolyzable groups on the silicon atom and constitutes the alkoxy oligomer represented by formula (1). is not particularly limited.

Examples of silane compounds include tetrachlorosilane, tetramethoxysilane, tetraethoxysilane; methyltrichlorosilane, methyltrimethoxysilane, methyltriethoxysilane; dimethyldimethoxysilane, dimethyldiethoxysilane; phenyltrichlorosilane, phenyltrimethoxysilane, phenyltriethoxysilane; phenylmethyldichlorosilane, phenylmethyldimethoxysilane, phenylmethyldiethoxysilane; diphenyldichlorosilane, diphenyldimethoxysilane, diphenyldiethoxysilane; and partial hydrolysates thereof. Methoxysilane and ethoxysilane are preferably used from the viewpoints of reactivity, operability, ease of distilling off by-products, and availability of raw materials. A silane compound can be used individually or in combination of 2 or more types.

Hydrolytic condensation can be carried out using a hydrolysis catalyst. Examples of hydrolysis catalysts include inorganic acids such as hydrogen fluoride, hydrochloric acid, nitric acid, sulfuric acid and phosphoric acid; organic acids such as methanesulfonic acid, p-toluenesulfonic acid, formic acid, acetic acid, maleic acid, benzoic acid and lactic acid. and cation exchange resins having sulfo or carboxy groups on the surface. The amount of the hydrolysis catalyst used is not particularly limited, but is preferably 0.0002 mol to 0.5 mol based on 1 mol of the silane compound. By setting the amount of the hydrolysis catalyst to be used within the above range, the hydrolytic condensation reaction can be effectively promoted and the catalyst after the reaction can be easily removed.

The amount of water used for hydrolytic condensation is not particularly limited, but it is preferably 0.1 to 10 mol based on 1 mol of the silane compound. By setting the amount of water to be used within the above range, deactivation of the catalyst can be prevented, the hydrolytic condensation reaction can be promoted, and water can be easily removed after the reaction.

The hydrolytic condensation reaction temperature is not particularly limited, but is preferably -10 to 150°C. By setting the reaction temperature within the above range, decomposition of the alkoxy group of the alkoxy oligomer to be produced can be suppressed while improving the reaction rate.

An organic solvent may be used in the hydrolytic condensation. Organic solvents include, for example, methanol, ethanol, propanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, toluene, and xylene.

<(B) Hydrophilic inorganic filler>
(B) The hydrophilic inorganic filler is not particularly limited, but examples thereof include calcium carbonate, silica, alumina, and titanium oxide. A hydrophilic inorganic filler can be used individually or in combination of 2 or more types.

The hydrophilic inorganic filler is preferably spherical. The average particle size of the hydrophilic inorganic filler is preferably 0.1 μm to 50 μm, more preferably 0.2 μm to 10 μm. By setting the average particle size of the hydrophilic inorganic filler to 0.1 μm or more, excessive thickening of the one-component water-curable adhesive can be suppressed. By setting the average particle diameter of the hydrophilic inorganic filler to 10 μm or less, the adhesiveness to the adherend can be enhanced. In the present disclosure, the average particle size of the hydrophilic inorganic filler is the volume cumulative particle size _D50 measured by laser diffraction scattering method.

The specific surface area of the hydrophilic inorganic filler is preferably 0.5 m ² /g to 15 m ² /g, more preferably 0.7 m ² /g to 10 m ² /g. In the present disclosure, the specific surface area of the hydrophilic inorganic filler is a value obtained by the BET method.

The hydrophilic inorganic filler is preferably not subjected to surface hydrophobizing treatment. Examples of the surface hydrophobization treatment include, in the case of silica, surface hydrophobization treatment using hexamethyldisilazane, dimethyldichlorosilane, higher alkyltrialkoxysilane, higher fatty acid, or the like.

The hydrophilic inorganic filler preferably contains at least one selected from the group consisting of fused spherical silica, deflagration spherical silica, and calcium carbonate particles, which are not surface-hydrophobicized.

Examples of fused spherical silica include FB-5D (average particle size: 4.7 μm, specific surface area: 2.4 m ² /g) (Denka Co., Ltd.). As deflagration method spherical silica, for example, ADMAFINE SILICA SO-C2 (average particle size 0.4-0.6 μm, specific surface area 4-7 m ² /g), SO-C4 (average particle size 0.9-1. 2 μm, specific surface area 3 to 6 m ² /g), and SO-C6 (average particle diameter 1.8 to 2.3 μm, specific surface area 1.5 to 2.5 m ² /g) (both from Admatechs Co., Ltd.) mentioned. Examples of calcium carbonate particles include super S (average particle diameter 6.3 μm, specific surface area 0.8 m ² /g), super #1500 (average particle diameter 2.2 μm, specific surface area 1.5 m ² /g) and Nanox #25 (average particle diameter 1.3 μm, specific surface area 2.5 m ² /g) (both from Maruo Calcium Co., Ltd.).

The content of the hydrophilic inorganic filler is preferably 250 to 700 parts by mass, more preferably 300 to 600 parts by mass, based on 100 parts by mass of the silicone polymer.

<(C) Curing catalyst>
(C) The curing catalyst is not particularly limited as long as it promotes hydrolysis of alkoxy groups and curing of alkoxy oligomers. Examples include metal alkoxide compounds including metals such as Al, Ti, Zr, and Sn, metal Chelate compounds and metal ester compounds are included. A curing catalyst can be used individually or in combination of 2 or more types.

Examples of metal alkoxide compounds include aluminum trimethoxide, aluminum triethoxide, aluminum tri-n-propoxide, aluminum triisopropoxide, aluminum tri-n-butoxide, aluminum triisobutoxide and aluminum tri-s-butoxide. , aluminum alkoxides such as aluminum tri-t-butoxide; Titanium alkoxides such as n-hexyl titanate, tetraisooctyl titanate, tetra-n-lauryl titanate; tetraethyl zirconate, tetra-n-propyl zirconate, tetraisopropyl zirconate, tetra-n-butyl zirconate, tetra-s- Butyl zirconate, tetra-t-butyl zirconate, tetra-n-pentyl zirconate, tetra-t-pentyl zirconate, tetra-t-hexyl zirconate, tetra-n-heptyl zirconate, tetra-n-octyl zirconate zirconium alkoxides such as tetra-n-stearyl zirconate; and tin alkoxides such as dibutyltin dibutoxide.

Examples of metal chelate compounds and metal ester compounds include tris(ethylacetoacetate)aluminum, tris(n-propylacetoacetate)aluminum, tris(isopropylacetoacetate)aluminum, tris(n-butylacetoacetate)aluminum, isopropoxy bis(ethylacetoacetate)aluminum, tris(acetylacetonato)aluminum, tris(propionylacetonato)aluminum, diisopropoxypropionylacetonatoaluminum, acetylacetonato-bis(propionylacetonato)aluminum, monoethylacetoacetate-bis (Acetylacetonato) Aluminum, Acetylacetonato Aluminum Di-s-Butyrate, Methylacetoacetate Aluminum Di-s-Butyrate, Di(Methylacetoacetate) Aluminum Mono-t-Butyrate, Diisopropoxyethylacetoacetate Aluminum , aluminum chelate compounds such as monoacetylacetonato bis (ethylacetoacetate) aluminum; diisopropoxy bis (ethylacetoacetate) titanate, diisopropoxy bis (acetylacetonato) titanate, di-n-butoxy bis Titanium chelate compounds such as (acetylacetonato) titanate; Zirconium chelate compounds such as tetrakis(acetylacetonato)zirconium, tetrakis(n-propylacetoacetate)zirconium, tetrakis(ethylacetoacetate)zirconium; and dibutyltin diacetate, dibutyltin diacetate (2-ethylhexylate), dibenzyltin di(2-ethylhexylate), dibutyltin dilaurate, dibutyltin diisooctyl maleate, dibutyltin bis(acetylacetonate) and other tin ester compounds.

From the viewpoint of curability in water, the curing catalyst is preferably at least one selected from the group consisting of titanium alkoxide compounds and titanium chelate compounds.

Curing catalysts include, for example, ORGATIX TC-750 (diisopropoxy bis(ethylacetoacetate) titanate, Matsumoto Fine Chemicals Co., Ltd.) and D-25 (titanium type, Shin-Etsu Chemical Co., Ltd.).

An amine-based silane coupling agent can also be used as a curing catalyst. Examples of amine-based silane coupling agents include KBE-903 (Shin-Etsu Chemical Co., Ltd.).

The content of the curing catalyst is preferably 0.2 to 8 parts by mass, more preferably 0.5 to 5 parts by mass, based on 100 parts by mass of the silicone polymer.

<(D) Nonpolar Organic Polymer Compound>
(D) The non-polar organic polymer compound is an optional component in the one-component water-curable adhesive of the first embodiment, and an essential component in the one-component water-curable adhesive of the second embodiment. The non-polar organic polymer compound does not dissolve in the above silicone polymer, which has a relatively high polarity, so it can impart thixotropic properties to the adhesive. This can suppress the dissolution of the adhesive in water and the separation of liquid components or low-molecular-weight components in the adhesive during low-temperature storage. Also, the non-polar organic polymer compound can be advantageously used to make the adhesive putty-like. Since the putty-like adhesive is difficult to deform or flow in a static state, it is possible to improve the adhesive stability immediately after application. In the second embodiment, the alkoxy group content of the silicone polymer tends to be relatively high, ie, the silicone polymer has a low molecular weight. Therefore, by including a non-polar organic polymer compound as an essential component, the viscosity of the adhesive can be increased, and the working stability in water and low-temperature storage stability of the adhesive can be ensured.

Non-polar organic polymer compounds include, for example, high-viscosity silicone oils, linear organopolysiloxanes such as raw silicone rubber, and polybutenes. The high-viscosity silicone oil and silicone raw rubber are preferably high-viscosity dimethylsilicone oil and dimethylsilicone raw rubber, respectively. The kinematic viscosity of the high-viscosity silicone oil is preferably 100,000 mm ² /s to 1,000,000 mm ² /s. A non-polar organic polymer compound can be used individually or in combination of 2 or more types.

In the first embodiment, the content of the optional non-polar organic polymer compound is preferably 1000 parts by mass or less, more preferably 10 to 500 parts by mass, based on 100 parts by mass of the silicone polymer. preferable. By setting the content of the non-polar organic polymer compound to 100 parts by mass or less, it is possible to suppress deterioration in adhesiveness.

In the second embodiment, the content of the nonpolar organic polymer compound is preferably 50 to 800 parts by mass, more preferably 60 to 500 parts by mass, based on 100 parts by mass of the silicone polymer.

<(E) Polyfunctional Alkoxysilane>
(E) The polyfunctional alkoxysilane reacts with the moisture contained in the inorganic filler during the production or storage of the adhesive, and reacts with the silicone polymer to cause the adhesive to deteriorate during storage. By suppressing or preventing crosslinking and curing, the storage stability of the adhesive can be enhanced.

Polyfunctional alkoxysilanes include, for example, tetraalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetrabutoxysilane; and methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, methyltriethoxysilane. and trialkoxysilanes such as butoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, butyltrimethoxysilane, butyltriethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane. . A polyfunctional alkoxysilane can be used individually or in combination of 2 or more types.

The polyfunctional alkoxysilane is preferably at least one selected from the group consisting of tetraethoxysilane and vinyltrimethoxysilane.

The content of the polyfunctional alkoxysilane is preferably 1 to 20 parts by mass, more preferably 5 to 15 parts by mass, based on 100 parts by mass of the silicone polymer.

<Optional component>
The adhesive may contain additives as optional components within a range that does not impair the effects of the present invention. Additives include, for example, solvents, silane coupling agents, rheology modifiers, dispersants, anti-aging agents, antioxidants, dyes, and pigments. Additives can be used alone or in combination of two or more.

<Manufacturing of one-component water curing adhesive>
A one-component water-curable adhesive can be produced by mixing the above components. As a mixing device, for example, a planetary mixer, a kneader, or the like can be used. The order of mixing the above components is not particularly limited, but it is preferable to first mix the components that are compatible with the silicone polymer, and then add and mix the hydrophilic inorganic filler to the resulting mixture.

<Form of one-component water curing adhesive>
In one embodiment, the one-component water-curable adhesive is provided in the form of a putty-type adhesive. Putty-type adhesives are especially excellent in workability in water.

<Uses of one-component water curing adhesive>
The one-component water-curable adhesive of the present disclosure can be suitably used for bonding inorganic materials such as metals and ceramics to adherends such as rocks and structures on the bottom of a river or in the sea.

EXAMPLES The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

<material>
Table 1 shows the alkoxy oligomers used in the one-component water-curable adhesives in the examples.

The methyl-based oligomer is an alkoxy oligomer represented by formula (1) in which ^R1 is a methyl group. A methylphenyl-based oligomer is an alkoxy oligomer represented by formula (1) in which R ¹ is a methyl group or a phenyl group. The Q oligomer is an alkoxy oligomer represented by formula (1) where a=1, b=0, and c=0.

As hydrophilic inorganic fillers, FB-5D (average particle size 4.7 μm, specific surface area 2.4 m ² /g) (Denka Co., Ltd.), which is fused spherical silica, and Super S, which is heavy untreated calcium carbonate particles (average particle size 6.3 μm, specific surface area 0.8 m ² /g) (Maruo Calcium Co., Ltd.) was used.

As curing catalysts, ORGATIX TC-750 (diisopropoxy bis(ethylacetoacetate) titanate, Matsumoto Fine Chemicals Co., Ltd.) and D-25 (titanium type, Shin-Etsu Chemical Co., Ltd.) were used.

Silicone raw rubber (linear dimethylpolysiloxane having a degree of polymerization of 8000) was used as the non-polar organic polymer compound.

Tetraethoxysilane (TEOS) and vinyltrimethoxysilane (VTMOS) were used as polyfunctional alkoxysilanes.

<Preparation of one-component water curing adhesive>
A one-part water-curable adhesive was prepared by the following procedure. Alkoxy oligomer, silicone raw rubber (if used), tetraethoxysilane (if used), curing catalyst, and hydrophilic inorganic filler are weighed in order into a 90 mL PET lidded circular container, and these are placed with wooden chopsticks. was stirred. The hydrophilic inorganic filler was added until all the hydrophilic inorganic filler was incorporated into the liquid phase, forming a uniform putty and making it difficult to stir.

<Adhesiveness>
Adhesiveness was evaluated by the following procedure. A test pebble was placed in artificial seawater prepared by dissolving commercially available mineral salt for artificial seawater in tap water. After lightly pressing a one-component water-curing adhesive balled into a sphere with a diameter of several centimeters by hand onto a pebble in artificial seawater, place the same type of stone on top of it, press it lightly, and leave it at room temperature. did. After a predetermined period of time, the pebbles were taken out, and the two pebbles were pulled by hand, and the force required for peeling was evaluated by the feel of the hand. The evaluation of adhesiveness is expressed in five stages of A +, A, B, C, and C-, where A + and A are practical adhesive strengths in various applications, and B is adhesive strength that can be used depending on the application, C and C- indicate that the bond strength was unusably low.

<Underwater work stability>
The state of the one-part water-curable adhesive during operation in water was observed and recorded.

<Stability in frozen storage>
Place the one-part water-curable adhesive in the circular container with a lid used for preparation, cover it, put the circular container with a lid in a PE bag with a zipper, and place it in the freezer compartment (-15°C) of a household refrigerator. saved with The state of the adhesive was observed periodically and recorded as cryopreservation stability.

<Room temperature storage stability>
The one-liquid water-curable adhesive was kept in the lidded circular container used for the preparation, and the lid was closed. The time or days for the adhesive to cure in the container was recorded.

<Examples 1-1 to 1-4, Comparative Examples 1-1 to 1-5>
Using various alkoxy oligomers, one-component underwater adhesives were prepared with the compositions shown in Table 2. Table 2 shows the composition and evaluation results. In Examples 1-1 to 1-4 and Comparative Examples 1-1 to 1-5, the one-component water-curable adhesive was rolled into a ball by hand in the air and then placed on a pebble.

<Examples 2-1 to 2-4, Comparative Examples 2-1 to 2-2>
For the purpose of improving the storage stability by adding a polyfunctional alkoxysilane, a one-component underwater adhesive was prepared with the composition shown in Table 3. Table 3 shows the composition and evaluation results. In Examples 2-1 to 2-4 and Comparative Examples 2-1 to 2-2, the one-component water-curable adhesive was rolled into a ball by hand in the air, and then placed on a pebble.

<Examples 3-1 to 3-6, Comparative Examples 3-1 to 3-2>
For the purpose of improving the stability of working in water by adding a non-polar organic polymer compound, a one-component underwater adhesive with the composition shown in Table 4 was prepared. Table 4 shows the composition and evaluation results. In Examples 3-1 to 3-6 and Comparative Examples 3-1 to 3-2, the one-component water-curable adhesive was manually rolled into a spherical shape in water and placed on a pebble.

The one-component water-curable adhesive of the present disclosure can be suitably used for bonding inorganic materials such as metals and ceramics to adherends such as rocks and structures on the bottom of a river or in the sea.

Claims (10)

(A) 100 parts by mass of a silicone polymer having a plurality of alkoxy groups having 1 to 6 carbon atoms directly bonded to silicon atoms;
(B) 200 to 800 parts by mass of a hydrophilic inorganic filler;
(C) A one-component water-curable adhesive containing 0.1 to 10 parts by mass of a curing catalyst, wherein the silicone polymer has an alkoxy group content of 20% to 40% by mass. mold glue. (A) 100 parts by mass of a silicone polymer having a plurality of alkoxy groups having 1 to 6 carbon atoms directly bonded to silicon atoms;
(B) 200 to 800 parts by mass of a hydrophilic inorganic filler;
(C) 0.1 to 10 parts by mass of a curing catalyst;
(D) A one-component water-curable adhesive containing 40 to 1000 parts by mass of a nonpolar organic polymer compound, wherein the silicone polymer has an alkoxy group content of 20% to 50% by mass. Underwater curing adhesive. 3. The one-part water-curable adhesive according to claim 2, wherein said non-polar organic polymer compound comprises a linear organopolysiloxane. The silicone polymer has the formula (1)
(SiO _4/2 ) _a (R ¹ SiO _3/2 ) _b (R ¹ ₂ SiO _2/2 ) _c (R ² O _1/2 ) _d (1)
(In formula (1), R ¹ each independently represents a methyl group or a phenyl group, R ² each independently represents a hydrogen atom, a methyl group, or an ethyl group, a, b, and c are 0 ≦a≦1, 0≦b≦1, 0≦c<0.5 and a+b+c=1, and d is a number satisfying 0<d<4).
4. The one-component water-curable adhesive according to any one of claims 1 to 3, comprising a partially hydrolyzed condensate of a polyfunctional alkoxysilane represented by. Any one of claims 1 to 4, wherein the hydrophilic inorganic filler contains at least one selected from the group consisting of fused spherical silica, deflagration spherical silica, and calcium carbonate particles, which are not surface-hydrophobicized. The one-liquid water-curable adhesive according to any one of items 1 to 1. The one-component water-curable adhesive according to any one of claims 1 to 5, wherein the hydrophilic inorganic filler has an average particle size of 0.1 µm to 50 µm. The one-component water-curable adhesive according to any one of claims 1 to 6, wherein the curing catalyst is at least one selected from the group consisting of titanium alkoxide compounds and titanium chelate compounds. 8. The one-component water-curable adhesive according to any one of claims 1 to 7, further comprising (E) a polyfunctional alkoxysilane. 9. The one-component water-curable adhesive according to claim 8, wherein said polyfunctional alkoxysilane is at least one selected from the group consisting of tetraethoxysilane and vinyltrimethoxysilane. The one-component water-curable adhesive according to claim 8 or 9, containing 1 to 20 parts by mass of the polyfunctional alkoxysilane.