JP7777975B2 - Polysiloxane resin and method for producing polysiloxane resin solution - Google Patents

Description

The present invention relates to a method for producing a polysiloxane-based resin and a polysiloxane-based resin solution.

Polysiloxane resins (polysiloxane-based resins) grafted with acrylic or other organic materials, compared to resins with inorganic properties such as polysiloxane-based resins, are attracting industrial attention due to their interesting properties as inorganic-organic hybrid resins.

Polysiloxane resins are known to produce highly durable cured products (coating films) and are used in a wide range of applications, including coatings, construction sealants, adhesives, and paints. In particular, in the paint industry, water-based paints containing polysiloxane resins are becoming increasingly popular in the market due to their minimal adverse effects on the human body and the environment, and demand for them in a variety of applications is growing.

As an example of such a polysiloxane-based resin, Patent Document 1 discloses a polysiloxane-based resin containing polysiloxane and acrylic silicone.

International Publication No. 2017/169459

While the above-mentioned technology is excellent, there is room for further improvement in terms of the flexibility and weather resistance of the cured product (cured film) obtained by curing the polysiloxane resin.

Therefore, one aspect of the present invention aims to provide a method for producing a polysiloxane-based resin that can produce a cured product with excellent flexibility and weather resistance.

As a result of extensive research aimed at solving the above-mentioned problems, the inventors discovered for the first time that a polysiloxane-based resin can be provided that can produce a cured product with excellent flexibility and weather resistance by radically polymerizing a condensate obtained by condensing a specific silane compound with a monomer having a radically polymerizable unsaturated group and an oligomer having a radically polymerizable unsaturated group, leading to the completion of the present invention.

Therefore, one aspect of the present invention is a compound represented by the following general formula (I):
R ¹ _n -Si-(OR ² ) _4-n ...(I)
(wherein each R ¹ is independently an alkyl group having 1 to 10 carbon atoms or an unsubstituted or substituted aryl group; each R ² is independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms; and n is an integer of 0 to 3), and a silane compound (B) having a radically polymerizable unsaturated group and a hydrolyzable silyl group; a monomer (C) having a radically polymerizable unsaturated group but not a hydrolyzable silyl group; and an oligomer (D) having a radically polymerizable unsaturated group, a main chain containing carbon atoms, no Si—O—Si bond, and a number average molecular weight of 1,000 to 100,000.

One aspect of the present invention provides a method for producing a polysiloxane-based resin that can produce a cured product with excellent flexibility and weather resistance.

One embodiment of the present invention is described in detail below. Note that unless otherwise specified in this specification, "A to B" representing a numerical range means "greater than or equal to A and less than or equal to B." Furthermore, all documents cited in this specification are incorporated herein by reference.

1. Overview of the present invention
The cured product (cured film) obtained by curing a polysiloxane resin exhibits high durability due to the high bond energy derived from the siloxane bond. However, the cured product tends to have low flexibility, which can lead to problems such as cracking of the cured product.

A method for improving the flexibility and suppressing cracking of cured products obtained by curing polysiloxane resins has been proposed, which involves grafting a monomer having a radically polymerizable unsaturated group, such as a (meth)acrylic monomer, onto the polysiloxane resin. In this method, suppressing cracking requires grafting a large amount of the monomer having a radically polymerizable unsaturated group onto the polysiloxane resin. However, the inventors have newly discovered that when a large amount of the monomer having a radically polymerizable unsaturated group is used, some of the monomer having the radically polymerizable unsaturated group does not polymerize into the polysiloxane resin, but instead polymerizes with itself. Furthermore, they have newly discovered that the polymer formed by the polymerization of the monomer having the radically polymerizable unsaturated group remains in the resulting polysiloxane resin as a free polymer (FP), and that cured products obtained by curing polysiloxane resins containing such free acrylic groups exhibit poor weather resistance. Furthermore, simply reducing the amount of monomer containing a radically polymerizable unsaturated group used makes it difficult to improve the flexibility of the cured product obtained by curing the polysiloxane resin.

In light of this situation, the present inventors conducted extensive research with the aim of providing a polysiloxane-based resin capable of providing a cured product with excellent flexibility and weather resistance. As a result, they discovered that by graft polymerizing a monomer having a radically polymerizable unsaturated group and an oligomer having a radically polymerizable unsaturated group onto a condensate (polysiloxane-based resin) obtained by condensing a specific silane compound, they could provide a polysiloxane-based resin capable of providing a cured product with excellent flexibility and weather resistance, leading to the completion of the present invention. Specifically, when only monomers having a radically polymerizable unsaturated group are graft polymerized onto a polysiloxane-based resin, there is a problem of a large amount of free monomer remaining. However, the present inventors discovered that by replacing a portion of the monomer having a radically polymerizable unsaturated group with one that has been slightly polymerized (oligomerized) in advance, it is possible to reduce the amount of free monomer, and as a result, the physical properties of the resulting cured product can be improved, imparting both resistance to weathering and flexibility.

As mentioned above, conventional polysiloxane resins have been unable to achieve both flexibility and weather resistance in the resulting cured product. Given these circumstances, it was a surprising discovery to have found a method for producing a polysiloxane resin that can provide a cured product that is both highly flexible and weather-resistant (a method for producing a polysiloxane resin according to one embodiment of the present invention). Furthermore, such polysiloxane resins are extremely useful, particularly in the field of paints.

Furthermore, a polysiloxane-based resin solution can be provided by dispersing or emulsifying the polysiloxane-based resin provided by the method for producing a polysiloxane-based resin according to one embodiment of the present invention in an aqueous medium (e.g., water). Even when the polysiloxane-based resin provided by the method for producing a polysiloxane-based resin according to one embodiment of the present invention is in the form of a polysiloxane-based resin solution, it can provide a cured product (cured film) that is excellent in both flexibility and weather resistance. For this reason, the method for producing a polysiloxane-based resin solution according to one embodiment of the present invention is extremely useful as a method for producing an aqueous paint.

2. Method for producing polysiloxane resin
A method for producing a polysiloxane resin according to one embodiment of the present invention (hereinafter, sometimes referred to as "the present production method") comprises reacting a compound represented by the following general formula (I):
R ¹ _n -Si-(OR ² ) _4-n ...(I)
(wherein R ¹ is independently an alkyl group having 1 to 10 carbon atoms or an unsubstituted or substituted aryl group, R and a polymerization step of radically polymerizing a condensate ( ^hereinafter sometimes simply referred to as the condensate) of a silane compound (A) represented by the formula (I) (hereinafter sometimes simply referred to as the silane compound (A)) and a silane compound (B) having a radically polymerizable unsaturated group and a hydrolyzable silyl group (hereinafter sometimes simply referred to as the silane compound (B)), a monomer (C) having a radically polymerizable unsaturated group but not a hydrolyzable silyl group (hereinafter sometimes simply referred to as the monomer (C)), and an oligomer (D) having a radically polymerizable unsaturated group, having a main chain containing carbon atoms, not containing a Si—O—Si bond, and having a number average molecular weight of 1,000 to 100,000 (hereinafter sometimes simply referred to as the oligomer (D)).

Because this manufacturing method has the above-mentioned configuration, it is possible to provide a polysiloxane-based resin that can produce a cured product with excellent flexibility and weather resistance.

<Condensation product>
A condensate according to one embodiment of the present invention (hereinafter sometimes referred to as the present condensate) is a condensate obtained by condensing a silane compound (A) with a silane compound (B). The present condensate can be said to be a condensate obtained by polymerizing a structural unit derived from the silane compound (A) with a structural unit derived from the silane compound (B) via an Si—O—Si bond, or can be said to be a condensate containing a structural unit derived from the silane compound (A) and a structural unit derived from the silane compound (B).

There are no particular restrictions on the number average molecular weight of this condensate, but it is preferably in the range of 500 to 100,000, and more preferably 1,000 to 10,000.

The number average molecular weight of this condensate is determined by gel permeation chromatography (GPC). Typically, chloroform is used as the mobile phase, and measurements are performed in a polystyrene gel column, and the number average molecular weight can be determined in polystyrene equivalent terms.

(Silane Compound (A))
The silane compound (A) according to one embodiment of the present invention is a compound having a hydrolyzable silyl group and represented by the following general formula (I):
R ¹ _n -Si-(OR ² ) _4-n ...(I)
(In the formula, each R ¹ is independently a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms or an unsubstituted or substituted aryl group, each R ² is independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and n is an integer of 0 to 3.)
The silane compound (A), together with the silane compound (B) described below, is a main component constituting the polysiloxane chain, which is the main chain of the present condensation product. The silane compound (A) can also be said to be a silane compound represented by the general formula (I) that has a hydrolyzable silyl group but does not have a radically polymerizable group.

Specific examples of the alkyl group for R ¹ in general formula (I) include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, an amyl group, an isoamyl group, a hexyl group, a cyclohexyl group, a cyclohexylmethyl group, a cyclohexylethyl group, a heptyl group, an isoheptyl group, an n-octyl group, an isooctyl group, and a 2-ethylhexyl group.

Specific examples of the aryl group in R ¹ of general formula (I) include a phenyl group, a naphthyl group, and a benzyl group.

^R2 in general formula (I) is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, an octyl group, a nonyl group, and a decyl group.

Specific compounds represented by general formula (I) include tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltriisopropoxysilane, propyltrimethoxysilane, propyltriethoxysilane, propyltriisopropoxysilane, butyltrimethoxysilane, butyltriethoxysilane, butyltriisopropoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, hexyltriisopropoxysilane, octyltrimethoxysilane, and octyltriethoxysilane. , octyltriisopropoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriisopropoxysilane, dimethyldimethoxysilane, diphenyldimethoxysilane, trimethylmonomethoxysilane, triphenylmonomethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, etc.

In general formula (I), n may be an integer between 0 and 3, but it is particularly preferable that n be 1. That is, the silane compound (A) is preferably a trialkoxysilane compound. When n is 1, there are three crosslinkable hydrolyzable silyl groups, making it possible to form a polymer with a stronger network structure. Specific examples of compounds in which n is 1 are methyltrimethoxysilane and phenyltrimethoxysilane, which are preferred from the standpoint of availability.

From the viewpoint of facilitating condensation of the silane compound (A) and the silane compound (B), the alkyl group of ^R2 in the general formula (I) preferably has 1 to 3 carbon atoms, and most preferably 1 carbon atom.

(Silane Compound (B))
The silane compound (B) according to one embodiment of the present invention is a silane compound having a radical polymerizable group and a hydrolyzable silyl group. In one embodiment of the present invention, the silane compound (B) is preferably a compound having a hydrolyzable silyl group represented by the following general formula (III):
R ³ _c R ⁴ _d -Si-(OR ⁵ ) _4-c-d ...(III)
(In the formula, ^R3 is a substituted alkyl group having 1 to 10 carbon atoms and having a polymerizable unsaturated group, an alkenyl group, or an aryl group having a polymerizable unsaturated group and optionally having other substituents; ^{each R4} is independently an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, or an unsubstituted or substituted aryl group; ^{each R5} is independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms; c is an integer of 1 to 3; d is an integer of 0 to 2; and c+d is an integer of 1 to 3.) In the above general formula (III), ^R3 and ^R4 are groups directly bonded to Si (silicon).

In general formula (III), c is an integer from 1 to 3, d is an integer from 0 to 2, and c+d may be an integer from 1 to 3. However, it is preferable that c is 1 and d is 0 or 1, and it is particularly preferable that c is 1 and d is 0. In other words, the silane compound (B) is preferably a trialkoxysilane compound.

^R3 in general formula (III) is a substituted alkyl group having 1 to 10 carbon atoms and having a radically polymerizable unsaturated group, an alkenyl group, or an unsubstituted or substituted aryl group having a radically polymerizable unsaturated group. The radically polymerizable unsaturated group is not particularly limited, but examples thereof include a (meth)acryloyl group and a (meth)acrylamide group. From the viewpoints of high reactivity and versatility, a (meth)acryloyl group is preferred.

Examples of the silane compound (B) in which R ³ is an alkyl group having a radical polymerizable unsaturated group include (meth)acryloxymethyltrimethoxysilane, (meth)acryloxymethylmethyldimethoxysilane, (meth)acryloxymethyldimethylmethoxysilane, (meth)acryloxymethyltriethoxysilane, (meth)acryloxymethylmethyldiethoxysilane, (meth)acryloxymethyldimethylethoxysilane, 2-(meth)acryloxyethyltrimethoxysilane, 2-(meth)acryloxyethylmethyldimethoxysilane, 2-(meth)acryloxyethylmethyldimethoxysilane, hydroxyethyldimethylmethoxysilane, 2-(meth)acryloxyethyltriethoxysilane, 2-(meth)acryloxyethylmethyldiethoxysilane, 2-(meth)acryloxyethyldimethylethoxysilane, γ-(meth)acryloxypropyltrimethoxysilane, γ-(meth)acryloxypropylmethyldimethoxysilane, γ-(meth)acryloxypropyldimethylmethoxysilane, γ-(meth)acryloxypropyltriethoxysilane, γ-(meth)acryloxypropylmethyldiethoxysilane, γ-(meth)acryloxypropyldimethyl ethoxysilane, 4-(meth)acryloxybutyltrimethoxysilane, 4-(meth)acryloxybutylmethyldimethoxysilane, 4-(meth)acryloxybutyldimethylmethoxysilane, 4-(meth)acryloxybutyltriethoxysilane, 4-(meth)acryloxybutylmethyldiethoxysilane, 4-(meth)acryloxybutyldimethylethoxysilane, 5-(meth)acryloxypentyltrimethoxysilane, 5-(meth)acryloxypentylmethyldimethoxysilane, 5-(meth)acryloxypentyldimethylmethoxysilane, 5- Examples thereof include (meth)acryloxypentyltriethoxysilane, 5-(meth)acryloxypentylmethyldiethoxysilane, 5-(meth)acryloxypentyldimethylethoxysilane, 6-(meth)acryloxyhexyltrimethoxysilane, 6-(meth)acryloxyhexylmethyldimethoxysilane, 6-(meth)acryloxyhexyldimethylmethoxysilane, 6-(meth)acryloxyhexyltriethoxysilane, 6-(meth)acryloxyhexylmethyldiethoxysilane, and 6-(meth)acryloxyhexyldimethylethoxysilane.

Examples of the silane compound (B) in which ^R3 is an alkenyl group include vinyltrimethoxysilane, vinylmethyldimethoxysilane, vinyldimethylmethoxysilane, vinyltriethoxysilane, vinylmethyldiethoxysilane, and vinyldimethylethoxysilane.

Examples of the silane compound (B) in which ^R3 is an aryl group having a polymerizable unsaturated group and optionally having other substituents include p-styryltrimethoxysilane, p-styrylmethyldimethoxysilane, p-styryldimethylmethoxysilane, p-styryltriethoxysilane, p-styrylmethyldiethoxysilane, and p-styryldimethylethoxysilane.

Among these, from the viewpoint of high reactivity and versatility, ^R3 is preferably a (meth)acryloyl group-substituted alkyl group or a vinyl group-substituted alkyl group.

In general formula (III), each R ⁴ is independently an unsubstituted or substituted alkyl group having 1 to 10 carbon atoms, or an unsubstituted or substituted aryl group.

Specific examples of the alkyl group in ^R4 in general formula (III) include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, an amyl group, an isoamyl group, a hexyl group, a cyclohexyl group, a cyclohexylmethyl group, a cyclohexylethyl group, a heptyl group, an isoheptyl group, an n-octyl group, an isooctyl group, and a 2-ethylhexyl group.

Specific examples of the aryl group in ^R4 of the general formula (III) include a phenyl group, a naphthyl group, and a benzyl group.

When c is 1 and d is 1, R ⁴ in general formula (III) is preferably a methyl group.

^R5 in the general formula (III) is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, an octyl group, a nonyl group, and a decyl group.

From the viewpoint of facilitating condensation of the silane compound (B) with the silane compound (A), the alkyl group of ^R5 in the general formula (III) preferably has 1 to 3 carbon atoms, and most preferably 1 carbon atom.

<Method for producing condensation product>
The method for producing the present condensate is not particularly limited, but for example, the present condensate can be provided by a condensation step of condensing a silane compound (A) with a silane compound (B). The present production method preferably includes a condensation step of condensing a silane compound (A) with a silane compound (B) before the polymerization step.

(Condensation step)
The condensation step is a step in which the silane compound (A) and the silane compound (B) are mixed in the presence of water (pure water) and a dehydration condensation catalyst to cause condensation (dehydration condensation).

The ratio of the amounts of silane compound (A) and silane compound (B) used in the condensation step is preferably 80 to 99 mol % of silane compound (A) and 1 to 20 mol % of silane compound (B), more preferably 85 to 97 mol % of silane compound (A) and 3 to 15 mol % of silane compound (B), and even more preferably 90 to 95 mol % of silane compound (A) and 5 to 10 mol % of silane compound (B), from the viewpoint of introducing an appropriate number of radically polymerizable unsaturated groups into the condensate and reducing excessive radical polymerization between the condensates in the polymerization step.

In one embodiment of the present invention, the number of moles (equivalents) of water (condensation water) added to dehydration-condense silane compound (A) and silane compound (B) is, for example, 0.25 times or more, preferably 0.5 times or more, relative to the total number of moles of each component. When the number of moles of water is 0.25 times or more relative to the total number of moles of each component, condensation can be carried out appropriately, and sufficient water resistance, weather resistance, and low tackiness can be expected. There is no particular limit to the number of moles of water, but from the perspective of storage stability, it is preferable to keep it to 4.0 times or less relative to the total number of moles of each component. Taking these points into consideration, the number of moles of water added in the condensation step is preferably 0.25 to 4.0 times, more preferably 0.5 to 3.0 times, and particularly preferably 1.0 to 2.5 times, relative to the total number of moles of each component.

The dehydration condensation catalyst used in the condensation step is not particularly limited as long as it is a substance capable of promoting the dehydration condensation reaction of the mixture containing silane compound (A) and silane compound (B). Examples include neutral salt catalysts, acidic catalysts, and basic catalysts. Of these, neutral salt catalysts are preferred from the standpoints of ease of synthesis and the storage stability of the resulting polysiloxane resin.

In this specification, the term "neutral salt catalyst" refers to a salt (neutral salt) formed from a strong acid and a strong base. Specifically, this refers to a salt formed by combining a cation selected from the group consisting of Group 1 element ions, Group 2 element ions, tetraalkylammonium ions, and guanidinium ions with an anion selected from the group consisting of Group 17 element ions (excluding fluoride ions), sulfate ions, nitrate ions, and perchlorate ions. Examples of neutral salts used as the neutral salt catalyst include lithium chloride, sodium chloride, potassium chloride, rubidium chloride, cesium chloride, francium chloride, beryllium chloride, magnesium chloride, calcium chloride, strontium chloride, barium chloride, radium chloride, tetramethylammonium chloride, tetraethylammonium chloride, tetrapropylammonium chloride, tetrabutylammonium chloride, tetrapentylammonium chloride, tetrahexylammonium chloride, and guanidium chloride; lithium bromide, sodium bromide, potassium bromide, rubidium bromide, cesium bromide, francium bromide, beryllium bromide, magnesium bromide, calcium bromide, strontium bromide, barium bromide, and radium bromide. Tetramethylammonium bromide, tetraethylammonium bromide, tetrapropylammonium bromide, tetrabutylammonium bromide, tetrapentylammonium bromide, tetrahexylammonium bromide, guanidium bromide; lithium iodide, sodium iodide, potassium iodide, rubidium iodide, cesium iodide, francium iodide, beryllium iodide, magnesium iodide, calcium iodide, strontium iodide, barium iodide, radium iodide, tetramethylammonium iodide, tetraethylammonium iodide, tetrapropylammonium iodide, tetrabutylammonium iodide, tetrapentylammonium iodide, tetrahexylammonium iodide, guanidium iodide; Lithium sulfate, sodium sulfate, potassium sulfate, rubidium sulfate, cesium sulfate, francium sulfate, beryllium sulfate, magnesium sulfate, calcium sulfate, strontium sulfate, barium sulfate, radium sulfate, tetramethylammonium sulfate, tetraethylammonium sulfate, tetrapropylammonium sulfate, tetrabutylammonium sulfate, tetrapentylammonium sulfate, tetrahexylammonium sulfate, guanidium sulfate; lithium nitrate, sodium nitrate, potassium nitrate, rubidium nitrate, cesium nitrate, francium nitrate, beryllium nitrate, magnesium nitrate, calcium nitrate, strontium nitrate, barium nitrate, radium nitrate, tetramethylammonium nitrate, tetraethylammonium nitrate Examples of neutral salts include ammonium nitrate, tetrapropylammonium nitrate, tetrabutylammonium nitrate, tetrapentylammonium nitrate, tetrahexylammonium nitrate, and guanidium nitrate; lithium perchlorate, sodium perchlorate, potassium perchlorate, rubidium perchlorate, cesium perchlorate, francium perchlorate, beryllium perchlorate, magnesium perchlorate, calcium perchlorate, strontium perchlorate, barium perchlorate, radium perchlorate, tetramethylammonium perchlorate, tetraethylammonium perchlorate, tetrapropylammonium perchlorate, tetrabutylammonium perchlorate, tetrapentylammonium perchlorate, tetrahexylammonium perchlorate, and guanidium perchlorate. These neutral salts may be used alone or in combination of two or more.

As the acidic catalyst, from the viewpoint of compatibility with the silane compound (A) and silane compound (B) or the dilution solvent, an organic acid catalyst is preferred, and phosphate esters and carboxylic acids can be suitably used. Specific examples of organic acids include ethyl acid phosphate, butyl acid phosphate, dibutyl pyrophosphate, butoxyethyl acid phosphate, 2-ethylhexyl acid phosphate, isotridecyl acid phosphate, dibutyl phosphate, bis(2-ethylhexyl) phosphate, formic acid, acetic acid, butyric acid, and isobutyric acid. These acidic catalysts may be used alone or in combination of two or more.

From the standpoint of compatibility with the silane compound (A) and silane compound (B) or the dilution solvent, the basic catalyst is preferably an organic base catalyst, and an amine compound can be suitably used. Specific examples of organic bases include triethylamine, diazabicycloundecene, and 1,4-diazabicyclo[2.2.2]octane. These basic catalysts may be used alone or in combination of two or more.

The amount of dehydration condensation catalyst is preferably 0.1 ppm to 50,000 ppm, more preferably 1 ppm to 10,000 ppm, particularly preferably 5 ppm to 1,000 ppm, and most preferably 10 ppm to 500 ppm, relative to the total amount of silane compound (A) and silane compound (B). When the amount of dehydration condensation catalyst is 0.1 ppm or more, it functions appropriately as a catalyst. While a larger amount of dehydration condensation catalyst can shorten the reaction time, it is often difficult to separate and remove it from the polysiloxane after the reaction is complete. Residual catalyst can reduce the storage stability of the polysiloxane resin obtained by this production method, so from a practical standpoint, the less catalyst used, the better, although this also takes into account the production time.

In the condensation step, a diluent solvent may be used in addition to silane compound (A), silane compound (B), water, and the dehydration condensation catalyst. Because silane compound (A) and silane compound (B) are hydrophobic and water is used during the reaction, it is preferable that the diluent solvent be water-soluble. There is no limit to the amount of diluent solvent, but using too much will result in a lower concentration of the resulting polysiloxane, which is undesirable from the perspective of production costs. Specific examples of dilution solvents include methanol, ethanol, 2-propanol, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, polyethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, diethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, ethylene glycol monoisobutyl ether, diethylene glycol monoisobutyl ether, propylene glycol monomethyl ether, propylene glycol dimethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, and ethylene glycol diethyl ether. Among these, methanol, ethanol, and 2-propanol are particularly preferred, considering the possibility of volatilization after production of the polysiloxane resin or during coating film formation.

<Polymerization process>
The polymerization step is a step of radically polymerizing the present condensate with the monomer (C) and the oligomer (D). It can also be said that the polymerization step is a step of radically polymerizing the present condensate with the monomer (C) and the oligomer (D) using a radical polymerization initiator.

(Monomer (C))
The monomer (C) is a monomer having a radically polymerizable unsaturated group but not a hydrolyzable silyl group. The radically polymerizable unsaturated group in the monomer (C) undergoes radical polymerization with the radically polymerizable unsaturated group derived from the silane compound (B), thereby forming a graft chain derived from the monomer (C) on the condensate.

Monomer (C) is not particularly limited as long as it is a monomer that has a radically polymerizable unsaturated group and does not have a hydrolyzable silyl group. Examples include monomers having a salt structure consisting of an acid and a base, (meth)acrylic acid alkyl esters, and other monomers, as shown below. One of these monomers may be used alone, or two or more may be used in combination. Among these, it is preferable that monomer (C) contains a monomer having a salt structure consisting of an acid and a base, as this has the advantage that the resulting polysiloxane-based resin is a polysiloxane-based resin that is uniformly dispersible or soluble in water and can be suitably used as an aqueous polysiloxane-based resin solution.

(Monomer having a salt structure consisting of an acid and a base)
In the monomer having a salt structure consisting of an acid and a base according to one embodiment of the present invention, the salt structure may be, for example, a neutral salt structure between a strong acid and a strong base, a neutral salt structure between a strong acid and a weak base, a neutral salt structure between a weak acid and a strong base, or a neutral salt structure between a weak acid and a weak base. More specific salt structures include, for example, sodium sulfonate, potassium sulfonate, calcium sulfonate, sodium nitrate, potassium nitrate, calcium nitrate, etc. (neutral salt structures between a strong acid and a strong base), ammonium sulfonate, ammonium nitrate, etc. (neutral salt structures between a strong acid and a weak base), sodium acetate, potassium acetate, calcium acetate, sodium phosphate, potassium phosphate, calcium phosphate, etc. (neutral salt structures between a weak acid and a strong base), ammonium acetate, ammonium phosphate, etc. (neutral salt structures between a weak acid and a weak base). In one embodiment of the present invention, the salt structure is preferably sodium sulfonate or ammonium sulfonate. In this specification, the term "monomer having a salt structure consisting of an acid and a base" can also be said to be "a monomer having a radically polymerizable unsaturated group, not having a hydrolyzable silyl group, and having a salt structure consisting of an acid and a base."

More specifically, examples of monomers having a salt structure consisting of an acid and a base include ADEKA REASOAP SR-05, SR-10, SR-20, SR-1025, SR-2025, SR-3025, SR-10S, NE-10, NE-20, NE-30, NE-40, SE-10, SE-20, ER-10, ER-20, ER-30, and ER-40 manufactured by ADEKA Corporation; and Antox-MS-60, RMA-1120, RMA-564, RMA-568, RMA-506, and MA-30 manufactured by Nippon Nyukazai Co., Ltd. MA-50, MA-100, MA-150, RMA-1120, MPG130-MA, MPG-130MA, RMA-150M, RMA-300M, RMA-450M, RA-1020, RA-1820, Aqualon KH-05, KH-10, RN-20, RN-30, RN-50, RN-2025, HS-10, HS-20, HS-1025, BC05, BC10, BC0515, BC1025 manufactured by Daiichi Kogyo Seiyaku Co., Ltd., and Eleminol JS-2, JS-20, RS manufactured by Sanyo Chemical Industries, Ltd. -30, Kao Corporation's Latemul S-180, S-180A, PD-104, PD-420, PD-430, sodium sulfoethyl methacrylate, sodium acrylamide-t-butylsulfonate, sodium 2-(methacryloyloxy)ethanesulfonate, sodium acrylamide-t-butylsulfonate, potassium 2-(methacryloyloxy)ethanesulfonate, potassium acrylamide-t-butylsulfonate, calcium 2-(methacryloyloxy)ethanesulfonate, calcium acrylamide-t-butylsulfonate, ammonium sulfoethyl methacrylate, ammonium acrylamide-t-butylsulfonate, ammonium 2-(methacryloyloxy)ethanesulfonate, ammonium acrylamide-t-butylsulfonate, sodium acrylate, potassium acrylate, calcium acrylate, ammonium acrylate, sodium methacrylate, potassium methacrylate, calcium methacrylate, ammonium methacrylate, etc.

((Meth)acrylic acid alkyl ester)
In one embodiment of the present invention, the (meth)acrylic acid alkyl ester is a (meth)acrylic acid ester having an alkyl group having 1 to 18 carbon atoms, and may be a (meth)alkyl monomer that does not contain functional groups such as a hydroxyl group or an epoxy group. In one embodiment of the present invention, the alkyl group in the (meth)acrylic acid alkyl ester may be linear or branched, or may be a cyclic cycloalkyl group. Specific examples thereof include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, iso-butyl (meth)acrylate, tert-butyl (meth)acrylate, benzyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isodecyl (meth)methacrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, and isobornyl (meth)acrylate.

(Monomers other than (meth)acrylic acid alkyl esters)
Examples of monomers other than (meth)acrylic acid alkyl esters include nitrile group-containing radically polymerizable monomers such as (meth)acrylonitrile; epoxy group-containing radically polymerizable monomers such as glycidyl (meth)acrylate; hydrophilic radically polymerizable monomers such as 2-hydroxypropyl (meth)acrylate; 2-hydroxypropyl (meth)acrylate; 2-sulfoethyl methacrylate sodium, 2-sulfoethyl methacrylate ammonium, and radically polymerizable monomers having a polyoxyalkylene chain; monomers having two or more polymerizable unsaturated bonds such as polyethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, and allyl (meth)acrylate; and fluorine-containing radically polymerizable monomers such as trifluoro(meth)acrylate, pentafluoro(meth)acrylate, perfluorocyclohexyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl methacrylate, and β-(perfluorooctyl)ethyl (meth)acrylate.

Furthermore, the radical polymerizable monomer having the above-mentioned polyoxyalkylene chain is not particularly limited, but an acrylic acid ester or a methacrylic acid ester having a polyoxyalkylene chain is preferred. Specific examples thereof include Blenmar PE-90, PE-200, PE-350, AE-90, AE-200, AE-350, PP-500, PP-800, PP-1000, AP-400, AP-550, AP-800, 700PEP-350B, 10PEP-550B, 55PET-400, 30PET-800, 55PET-800, 30PPT-800, 50PPT-800, 70PPT-800, PME-100, PME-200, PME-400, PME-1000, PME-4000, AME-400, and 50POEP-8, all manufactured by Nippon Oil & Fats Co., Ltd. 00B, 50AOEP-800B, AEP, AET, APT, PLE, ALE, PSE, ASE, PKE, AKE, PNE, ANE, PNP, ANP, PNEP-600, Light Ester 130MA, 041MA, MTG, Light Acrylate EC-A, MTG-A, 130A, DPM-A, P-200A, NP-4EA, NP-8EA, EHDG-A manufactured by Kyoeisha Chemical Co., Ltd., MA-30, MA-50, MA-100, MA-150, RMA-1120, RMA-564, RMA-568, RMA-506, MPG130-MA, Antox manufactured by Nippon Nyukazai Co., Ltd. Examples include MS-60, MPG-130MA, RMA-150M, RMA-300M, RMA-450M, RA-1020, RA-1120, RA-1820, and Shin-Nakamura Chemical Co., Ltd.'s NK-ESTER M-20G, M-40G, M-90G, M-230G, AMP-10G, AMP-20G, AMP-60G, AM-90G, and LA.

The amount of monomer (C) used in the polymerization step is not particularly limited. However, from the perspective of reducing the generation of excess free polymers, the ratio of the total number (moles) of radically polymerizable unsaturated groups in the condensate to the total number (moles) of radically polymerizable unsaturated groups in monomer (C) is preferably 1:1 to 1:100, more preferably 1:2 to 1:50, and even more preferably 1:5 to 1:25. The radically polymerizable unsaturated groups in the condensate are derived from silane compound (B). Therefore, the total number (moles) of radically polymerizable unsaturated groups in the condensate is calculated by multiplying the total number (moles) of silane compounds (B) contained in the condensate by the number of radically polymerizable unsaturated groups in the silane compounds (B).

(Oligomer (D))
The oligomer (D) has a radically polymerizable unsaturated group, its main chain contains carbon atoms, it does not contain Si—O—Si bonds, and its number average molecular weight is 1,000 to 100,000. The radically polymerizable unsaturated group in the oligomer (D) undergoes radical polymerization with the radically polymerizable unsaturated group derived from the silane compound (B) and/or the radically polymerizable unsaturated group derived from the monomer (C), thereby forming a graft chain with the condensate. The structure of the oligomer (D) may be linear or branched.

In this specification, the phrase "the main chain of oligomer (D) contains carbon atoms" means that the structural units constituting the main chain of the oligomer are bonded via a -C-O- bond or a -C-C- bond. In one embodiment of the present invention, the main chain of oligomer (D) may have at least two structural units bonded together via a -C-O- bond or a -C-C- bond, and all structural units may be bonded via a -C-O- bond or a -C-C- bond.

As used herein, "the main chain of oligomer (D) does not contain Si-O-Si bonds" means that the structural units constituting the main chain of the oligomer are not bonded to each other via Si-O-Si bonds (sometimes referred to as siloxane bonds). In other words, oligomer (D) is a condensate obtained by dehydration condensation of a compound having a hydrolyzable silyl group (in other words, a polymer obtained by polymerizing structural units derived from a compound having a hydrolyzable silyl group via Si-O-Si bonds), but it is a different substance from this condensate.

The main chain of the oligomer (D) according to one embodiment of the present invention is preferably at least one selected from the group consisting of polyalkylene oxide polymers, poly(meth)acrylic polymers, and polyisobutylene polymers, as this has the advantage of being easy to synthesize. In particular, poly(meth)acrylic polymers are more preferred, as they can provide a cured product with superior weather resistance.

(Polyalkylene oxide polymer)
In one embodiment of the present invention, the main chain of the oligomer (D) may be a polyalkylene oxide polymer. Examples of the main structural unit (alkylene oxide monomer unit) of the polyalkylene oxide polymer include ethylene oxide and propylene oxide. The oligomer (D) whose main chain is a polyalkylene oxide polymer can be obtained, for example, by polymerizing an alkylene oxide monomer by a known method.

In one embodiment of the present invention, the main chain of oligomer (D), whose main chain is a polyalkylene oxide polymer, may be a polymer obtained by copolymerizing, or even block copolymerizing, an alkylene oxide monomer with other conventionally known monomers. Furthermore, when the main chain of oligomer (D), whose main chain is a polyalkylene oxide polymer, contains other conventionally known monomers in addition to an alkylene oxide monomer, it is preferable that the main chain of oligomer (D) contains 40% by weight or more of structural units derived from alkylene oxide monomers, based on 100% by weight of the total amount of the main chain.

(Poly(meth)acrylic polymer)
In one embodiment of the present invention, the main chain of the oligomer (D) is preferably a poly(meth)acrylic polymer. Various types of units can be used as the main structural unit ((meth)acrylic monomer unit) of the poly(meth)acrylic polymer. Examples include (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, and decyl (meth)acrylate. and (meth)acrylic acid-based monomers such as dodecyl (meth)acrylate, phenyl (meth)acrylate, toluyl (meth)acrylate, benzyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, stearyl (meth)acrylate, glycidyl (meth)acrylate, 2-aminoethyl (meth)acrylate, γ-(methacryloyloxypropyl)trimethoxysilane, and ethylene oxide adducts of (meth)acrylic acid. The oligomer (D) whose main chain is a poly(meth)acrylic polymer can be obtained, for example, by polymerizing these (meth)acrylic monomers by a known method.

These (meth)acrylic acid monomers may be used alone or in combination. From the viewpoint of the physical properties of the resulting oligomer (D) having a poly(meth)acrylic polymer as its main chain, (meth)acrylic acid ester monomers are preferred, with acrylic acid ester monomers being more preferred, and (meth)acrylic acid alkyl ester monomers having an alkyl group ester-bonded to (meth)acrylic acid being particularly preferred. More specifically, the (meth)acrylic acid alkyl ester monomers include (meth)acrylic acid alkyl ester monomers having an alkyl group, such as 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-butoxyethyl (meth)acrylate, and isopropoxyethyl (meth)acrylate, wherein the alkyl group has an alkoxy group having 1 to 5 carbon atoms; (meth)acrylic acid alkyl ester monomers having an alkyl group having 1 to 5 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, and tert-butyl (meth)acrylate; (Meth)acrylic acid alkyl ester monomers having an alkyl group containing 6 to 15 carbon atoms, such as n-hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, and tetradecyl (meth)acrylate; and (meth)acrylic acid alkyl ester monomers having an alkyl group containing 16 to 25 carbon atoms, such as pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, eicosyl (meth)acrylate, and docosyl (meth)acrylate.

In one embodiment of the present invention, the main chain of oligomer (D), whose main chain is a poly(meth)acrylic polymer, may be a polymer obtained by copolymerizing, or even block copolymerizing, a (meth)acrylic monomer with another conventionally known monomer. When the main chain of oligomer (D), whose main chain is a poly(meth)acrylic polymer, contains another conventionally known monomer in addition to a (meth)acrylic monomer, it is preferable that the main chain of oligomer (D) contains 40% by weight or more of structural units derived from a (meth)acrylic monomer, based on 100% by weight of the total amount of the main chain.

(Polyisobutylene polymer)
In one embodiment of the present invention, the main chain of the oligomer (D) may be a polyisobutylene polymer. A polyisobutylene polymer is a polymer having an isobutylene unit as a main structural unit. The oligomer (D) having a polyisobutylene polymer main chain can be obtained, for example, by polymerizing an isobutylene monomer by a known method.

In one embodiment of the present invention, oligomer (D) whose main chain is a polyisobutylene-based polymer may be a polymer obtained by copolymerizing or even block copolymerizing isobutylene with other conventionally known monomers. When the main chain of oligomer (D) whose main chain is a polyisobutylene-based polymer contains other conventionally known monomers in addition to isobutylene, it is preferable that the main chain of oligomer (D) contains 40% by weight or more of structural units derived from isobutylene, based on 100% by weight of the total amount of the main chain.

The number average molecular weight of oligomer (D) may be 1,000 to 100,000, preferably 5,000 to 50,000, and more preferably 10,000 to 25,000. Having the number average molecular weight of oligomer (D) within the above range allows for the provision of a cured product with excellent flexibility and weather resistance.

Here, the number average molecular weight of oligomer (D) is determined by gel permeation chromatography (GPC). Typically, chloroform is used as the mobile phase, and measurement is performed in a polystyrene gel column, and the number average molecular weight can be determined in polystyrene equivalent terms.

The number of radically polymerizable unsaturated groups possessed by oligomer (D) is not particularly limited as long as it is one or more. However, if oligomer (D) contains three or more radically polymerizable unsaturated groups, gelation may occur during synthesis. Therefore, it is preferable that oligomer (D) contain one or two radically polymerizable unsaturated groups.

Oligomer (D) may (1) have a radically polymerizable unsaturated group in the main chain, (2) have a radically polymerizable unsaturated group at the end of the main chain, or (3) have a radically polymerizable unsaturated group both in the main chain and at the end of the main chain. Among these, oligomer (D) having (2) a radically polymerizable unsaturated group at the end of the main chain is preferred due to ease of synthesis.

The amount of oligomer (D) used in the polymerization step is not particularly limited, but from the perspective of reducing the generation of excess free polymers, the ratio of the total number (moles) of radically polymerizable unsaturated groups derived from silane compound (B) in the condensate to the total number (moles) of radically polymerizable unsaturated groups in oligomer (D) is preferably 200:1 to 5:1, more preferably 100:1 to 10:1, and even more preferably 80:1 to 20:1.

(Radical polymerization initiator)
The radical polymerization initiator is not particularly limited as long as it is a substance capable of initiating a radical polymerization reaction between the radical polymerizable group derived from the silane compound (B) and the radical polymerizable groups derived from the monomer (C) and the oligomer (D) in the present condensate.

In one embodiment of the present invention, examples of radical polymerization initiators include 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylbutyronitrile), tert-butyl peroxypivalate, tert-butyl peroxybenzoate, tert-butylperoxy-2-ethylhexanoate, di-tert-butyl peroxide, cumene hydroperoxide, and diisopropyl peroxycarbonate.

In one embodiment of the present invention, the amount of radical polymerization initiator is, for example, 0.01 to 10% by weight, preferably 0.05 to 7% by weight, and more preferably 0.1 to 5% by weight, relative to the total amount (100% by weight) of the condensate to be subjected to the polymerization step. When the amount of radical polymerization initiator is 0.01% by weight or more, radical polymerization proceeds appropriately. Furthermore, when the amount of radical polymerization initiator is 10% by weight or less, a polymer with an appropriate molecular weight can be obtained.

In the polymerization step, in addition to the condensate, monomer (C), oligomer (D), and radical polymerization initiator, any additives may be added as long as the effects of the present invention are achieved. Such additives can be appropriately selected by those skilled in the art.

3. Method for producing polysiloxane resin solution
A polysiloxane-based resin solution can be provided by dispersing, emulsifying, or dissolving the polysiloxane-based resin obtained by this production method in water. That is, a method for producing a polysiloxane-based resin solution according to one embodiment of the present invention (hereinafter sometimes referred to as the present resin solution production method) includes a step of dispersing, emulsifying, or dissolving the polysiloxane-based resin obtained by this production method in water. The step of dispersing, emulsifying, or dissolving the polysiloxane-based resin in water can also be considered a step of mixing the polysiloxane-based resin with water.

The polysiloxane resin solution obtained by this resin solution manufacturing method contains this polysiloxane resin, and therefore can provide a cured product with excellent flexibility and weather resistance. Therefore, it can be suitably used in water-based paint applications.

In the resin solution manufacturing method, when the polysiloxane resin obtained by this manufacturing method is mixed with water, additives commonly used in the relevant technical field (particularly the field of paints) may be further mixed in, as long as the effects of the present invention are achieved. Examples of such additives include curing catalysts, pigments, fillers, plasticizers, film-forming aids, wetting agents, dispersants, thickeners, antifoaming agents, preservatives, antioxidants, anti-settling agents, leveling agents, UV absorbers, antistatic agents, antifreeze agents, antibacterial agents, anti-mold and anti-algae agents, tackifiers, and rust inhibitors. Only one type of additive may be used, or two or more types may be used. Those skilled in the art can appropriately determine the amounts of these additives depending on the intended use.

The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

That is, one aspect of the present invention includes the following.
<1> The following general formula (I): R ¹ _n —Si—(OR ² ) _4-n (I)
(wherein, each R ¹ is independently an alkyl group having 1 to 10 carbon atoms or an unsubstituted or substituted aryl group, each R ² is independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and n is an integer of 0 to 3), and (B) a silane compound having a radical polymerizable unsaturated group and a hydrolyzable silyl group;
a monomer (C) having a radically polymerizable unsaturated group but not having a hydrolyzable silyl group; and an oligomer (D) having a radically polymerizable unsaturated group, a main chain containing carbon atoms, not containing a Si—O—Si bond, and a number average molecular weight of 1,000 to 100,000.
<2> The method for producing a polysiloxane-based resin according to <1>, wherein the main chain of the oligomer (D) is at least one selected from the group consisting of a polyalkylene oxide polymer, a poly(meth)acrylic polymer, and a polyisobutylene polymer.
<3> The method for producing a polysiloxane resin according to <1> or <2>, wherein the oligomer (D) has one or two radically polymerizable unsaturated groups.
<4> The method for producing a polysiloxane resin according to any one of <1> to <3>, wherein the oligomer (D) has a radically polymerizable unsaturated group at its terminal.
<5> the total number of radically polymerizable unsaturated groups derived from the silane compound (B) contained in the condensate, and the total number of radically polymerizable unsaturated groups contained in the oligomer (D),
<4> The method for producing a polysiloxane resin according to any one of <1> to <4>, wherein the ratio of
<6> The method for producing a polysiloxane resin according to any one of <1> to <5>, wherein the monomer (C) includes a monomer having a salt structure formed from an acid and a base.
<7> A method for producing a polysiloxane-based resin solution, comprising a step of dispersing, emulsifying, or dissolving in water the polysiloxane-based resin obtained by the production method according to any one of <1> to <6>.

The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

〔material〕
The following materials were used in the examples and comparative examples.

<Silane Compound (A)>
Methyltrimethoxysilane (abbreviated as "M-TMS"): "Z-6033" manufactured by Dow Toray Industries, Inc.
Phenyltrimethoxysilane (abbreviated as "Ph-TMS"): "Z-6124" manufactured by Dow Toray Industries, Inc.
<Silane Compound (B)>
Vinyltrimethoxysilane (abbreviated as "Vi-TMS"): "A-171" manufactured by Momentive
<Monomer (C)>
Methyl methacrylate (abbreviated as "MMA"): manufactured by Mitsubishi Gas Chemical Company, Inc. Butyl acrylate (abbreviated as "BA"): manufactured by Nippon Shokubai Co., Ltd. Ether sulfate type ammonium salt (abbreviated as "SR-10"): "ADEKA REASOAP SR-10" manufactured by ADEKA Corporation
Sodium acrylamide-t-butylsulfonate: "ATS" manufactured by Toagosei Co., Ltd.
<Materials for Oligomer (D)>
Ethyl 2-bromoadipate (Tokyo Chemical Industry Co., Ltd.)
Cuprous bromide: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Acetonitrile: Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Pentamethyldiethylenetriamine (abbreviated as "triamine"): Manufactured by Tokyo Chemical Industry Co., Ltd. Toluene: Manufactured by Mitsubishi Chemical Corporation Potassium acrylate: Manufactured by Nippon Shokubai 4-Hydroxy-TEMPO: Manufactured by Sigma-Aldrich Dimethylacetamide: Manufactured by Mitsubishi Gas Chemical Company, Inc. <Other ingredients>
(Dehydration condensation catalyst)
Lithium chloride (abbreviated as "LiCl"): neutral salt manufactured by Kanto Chemical Co., Ltd. (radical polymerization initiator)
2,2'-Azobis(2,4-dimethylvaleronitrile): "V-65" manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.
(others)
Condensed water (pure water)
[Measurement and evaluation methods]
Measurements and evaluations in the examples and comparative examples were carried out by the following methods.

(synthesis)
When polysiloxane-based resins were produced by the methods described in the Examples and Comparative Examples, the cases in which gelation did not occur during the synthesis (polymerization) of the polysiloxane-based resin were evaluated as "○ (good)," and the cases in which gelation occurred were evaluated as "× (bad)."

(Weather resistance (gloss retention))
The weather resistance of the cured product obtained by curing the obtained polysiloxane-based resin was evaluated with reference to WO 2016/052636 and Japanese Patent No. 5555449.

Briefly, an accelerated weathering test was conducted on the cured film (cured product) on the test piece prepared using the method described below using a metal halide lamp testing machine (Model KU-R5CI-A, manufactured by Daipla Wintes Co., Ltd.). The 60° gloss value of the cured film was measured before and after 400 hours of accelerated weathering test, and the gloss retention rate was calculated. A higher gloss retention rate indicates better weathering resistance.

The test conditions for the accelerated weathering test are as follows:

Illuminance: 85mW/ ^cm2
Irradiation: 63°C, 50%, 6 hours. Condensation: 30°C, 98%, 2 hours. Shower: 30 seconds before and after condensation.

(flexibility)
The flexibility of the cured product obtained by curing the obtained polysiloxane-based resin was measured with reference to JIS A6909. Briefly, the polysiloxane-based resin was applied to a 0.3 mm thick galvanized steel plate to a film thickness of 50 μm, and then cured for 2 weeks at 23°C and 50% RH to form a coating film (cured product). After curing, the galvanized steel plate was bent 90 degrees with a curvature diameter of 10 mm to measure the flexibility of the coating film (cured product). When the coating film did not crack upon bending, it was rated as "good," and when cracks occurred in the coating film, it was rated as "poor."

Synthesis Example 1
(Preparation of Oligomer (D))
0.42 parts by weight of cuprous bromide and 20.0 parts by weight of butyl acrylate were added to a deoxygenated reactor and heated with stirring at 80°C. Furthermore, 8.8 parts by weight of acetonitrile as a polymerization solvent and 1.90 parts by weight of ethyl 2-bromoadipate as an initiator were added to the reactor and mixed at 80°C. The temperature of the mixed solution was adjusted to approximately 80°C, and 0.02 parts by weight of triamine was added to initiate the polymerization reaction. After the polymerization reaction began, 80.0 parts by weight of butyl acrylate was gradually added to the reactor to advance the polymerization reaction. During the polymerization reaction, the rate of the polymerization reaction was adjusted by adding additional triamine as needed. The total amount of triamine used in the polymerization reaction was 0.15 parts by weight. The polymerization reaction was terminated when the monomer conversion rate (polymerization reaction rate) reached approximately 95% or higher, and the volatile components were removed by devolatilization under reduced pressure to obtain a polymer concentrate.

The resulting concentrate was diluted with toluene, and a filter aid, adsorbent (Kyoward 700SEN, manufactured by Kyowa Chemical Industry Co., Ltd.), and hydrotalcite (Kyoward 500SH, manufactured by Kyowa Chemical Industry Co., Ltd.) were added. The mixture was heated and stirred at approximately 80-100°C, and the solid components were then filtered off. The filtrate was then concentrated under reduced pressure to obtain a crude polymer.

To the resulting crude polymer, 1.98 parts by weight of potassium acrylate, 100 ppm of 4-hydroxy-TEMPO, and 100 parts by weight of dimethylacetamide (manufactured by Mitsubishi Gas Chemical Company, Inc.) as a solvent were added, and the mixture was allowed to react at 70°C for 3 hours. After the reaction, the solvent was distilled off under reduced pressure to obtain a polymer concentrate. The resulting concentrate was diluted with toluene, and the solid components were removed by filtration. The filtrate was concentrated under reduced pressure to obtain oligomer (D) having one radically polymerizable unsaturated group, an acryloyl group, at one end and a number-average molecular weight of 14,000.

Example 1
(Preparation of condensation product)
A reactor equipped with a stirrer, a thermometer, and a reflux condenser was charged with the silane compound (A) and the silane compound (B) in the amounts and types shown in Table 1, LiCl as a dehydration condensation catalyst, and pure water as condensation water, and the mixture was refluxed and stirred at a reaction temperature of 65°C for 3 hours to produce a condensation product (condensation step). Note that gelation did not occur during the condensation reaction.

(Polymerization process)
The condensate obtained in the condensation step was placed in a reactor equipped with a stirrer, a thermometer, a reflux condenser, a nitrogen gas inlet tube, and a dropping funnel, and the temperature was raised to 65°C while introducing nitrogen gas, and then a mixed solution of the monomer (C) in the amount and type shown in Table 1, the oligomer (D) prepared in Production Example 1 above, and 0.1 part by weight of V-65 as a polymerization initiator was added dropwise from the dropping funnel over 5 hours at a constant rate. The mixture was then stirred at 65°C for 2 hours and then cooled to room temperature, yielding a polysiloxane resin.

(Preparation of polysiloxane resin solution)
The prepared polysiloxane resin was subjected to devolatilization using a rotary evaporator until the nonvolatile content reached 90% or more. The resulting devolatilized polysiloxane resin was then dissolved in water to a nonvolatile content of 40%, and the solution was cooled to room temperature to obtain an aqueous solution containing the polysiloxane resin.

(Preparation of water-based paint)
The resulting polysiloxane resin solution was mixed with the components according to the formulation shown in Table 2 to prepare a water-based paint containing a polysiloxane resin (white base paint).

(Preparation of test specimens)
Test pieces for measuring and evaluating "weather resistance" were prepared with reference to WO 2016/052636. Briefly, the water-based paint prepared in the above (Preparation of Water-Based Paint) was applied to an aluminum plate (50 mm x 150 mm) coated with Hi-Pon Fine Primer II (manufactured by Nippon Paint Co., Ltd.) as a primer using an air spray to a dry film thickness of approximately 40 μm, and the resulting plate was dried at 23°C and 50% RH for one week to obtain a coated plate (aluminum plate coated with a cured product). This coated plate was used as a test piece. The obtained test piece was used to measure and evaluate the weather resistance and flexibility of the cured product obtained by curing the obtained polysiloxane-based resin. The results are shown in Table 1.

[Examples 2 to 3, Comparative Examples 1 to 3]
A polysiloxane resin, a polysiloxane resin solution, and an aqueous paint were prepared in the same manner as in Example 1, except that the type and amount of each component (synthesis recipe) were changed as shown in Tables 1 and 2. The resulting polysiloxane resin and the cured product obtained by curing the polysiloxane resin were measured and evaluated for the presence or absence of gelation during synthesis, as well as weather resistance and flexibility. The results are shown in Table 1.

In Table 1, all values are in parts by weight unless otherwise specified.

In Table 2, all values are in parts by weight unless otherwise specified.

〔result〕
Table 1 shows that the polysiloxane resins of Examples 1 to 3 obtained by this production method can provide cured products with excellent flexibility and weather resistance. It also shows that the polysiloxane resins of Examples 1 to 3 can be stably produced without gelation occurring during synthesis. In other words, this production method can provide polysiloxane resins that can provide cured products with excellent flexibility and weather resistance, and it was demonstrated that the polysiloxane resins can be stably produced without gelation.

On the other hand, a comparison of Examples 1 to 3 with Comparative Example 1 shows that when oligomer (D) is not used, the cured product obtained by curing the resulting polysiloxane-based resin has poor weather resistance. Furthermore, a comparison of Example 3 with Comparative Examples 2 and 3 shows that when oligomer (D) is not used and the amount of condensate (amount of silane compound (A) and silane compound (B) used) is increased, the cured product obtained by curing the resulting polysiloxane-based resin has poor flexibility. These results demonstrate that when oligomer (D) is not used, the cured product obtained by curing the resulting polysiloxane-based resin cannot achieve both flexibility and weather resistance.

The present invention provides a method for producing polysiloxane resins that can produce cured products with excellent flexibility and weather resistance. Cured products with excellent flexibility and weather resistance can be used effectively in coating agents, water-based paints, and the like.

Claims (5)

The following general formula (I):
R ¹ _n -Si-(OR ² ) _4-n ...(I)
(wherein ^R1 's each independently represent an alkyl group having 1 to 10 carbon atoms or an aryl group, ^R2 's each independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and n is 1 ),
a silane compound (B) having a radical polymerizable unsaturated group and a hydrolyzable silyl group;
and a condensation product of
a monomer (C) having a radical polymerizable unsaturated group and not having a hydrolyzable silyl group;
an oligomer (D) having a radically polymerizable unsaturated group, a main chain containing carbon atoms and no Si—O—Si bond, and a number average molecular weight of 1,000 to 100,000;
a polymerization step of radically polymerizing the
the ratio of the total number of radically polymerizable unsaturated groups derived from the silane compound (B) contained in the condensate to the total number of radically polymerizable unsaturated groups contained in the oligomer (D) is 200:1 to 5:1;
The method for producing a polysiloxane resin includes, as the monomer (C), a monomer having a salt structure formed from an acid and a base . The method for producing a polysiloxane-based resin according to claim 1, wherein the main chain of the oligomer (D) is at least one selected from the group consisting of polyalkylene oxide polymers, poly(meth)acrylic polymers, and polyisobutylene polymers. The method for producing a polysiloxane resin according to claim 1 or 2, wherein the oligomer (D) has one or two radically polymerizable unsaturated groups. The method for producing a polysiloxane resin according to any one of claims 1 to 3, wherein the oligomer (D) has a radically polymerizable unsaturated group at its terminal. A method for producing a polysiloxane resin solution, comprising a step of dispersing, emulsifying, or dissolving the polysiloxane resin obtained by the production method according to any one of claims 1 to 4 in water.