JPH10259371A - Surface treatment method for water-absorbing substance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect the surface of a water-absorbing substance to improve its waterproofness, antifouling properties, weatherability, etc., by coating it with a polymer which is produced by using an alcohol-soluble ethylenically unsatd. fluoroalkylated monomer as a comonomer. SOLUTION: The surface of a water-absorbing substance is coated with a polymer which is produced by polymerizing a monomer mixture contg. an alcohol-soluble ethylenically unsatd. fluoroalkylated monomer (A), pref. having at least two fluoroalkyl groups, as the essential comonomer and pref. further contg. an ethylenically unsatd. monomer having a polysiloxane chain (B) as a comonomer. The amt. of monomer A introduced into the polymer, though dependent on the performance level required, is pref. 5-90 wt.% when the monomer has one fluoroalkyl group and is pref. 0.1-70 wt.% when the monomer has two or more fluoroalkyl groups.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention protects a water-absorbing substance by applying a fluorine-containing polymer soluble in alcohol to the water-absorbing substance, and improves water absorption, antifouling property, weather resistance and the like. To a surface treatment method.

[0002]

2. Description of the Related Art Wood, paper and textiles are used for building materials, household goods,
It is a material used in large quantities on a daily basis as clothing. However, since such materials have high water absorption, they have various adverse effects such as decay, decrease in mechanical strength, and decrease in dimensional stability due to changes in the use environment and absorption of water during long-term use. Occurs.

In order to solve such a problem, a number of methods are known, and a method using a fluorine-based material has been proposed. For example, JP-A-8-5364
The publication describes that a coating of fluorinated urethane containing perfluoropolyether can protect the surface more durably than before.
However, there is a concern that such a method as a paint or a coating agent may impair the feel of the substrate itself.

In Japanese Patent Application Laid-Open No. 5-318413, as a method of improving water / oil repellency and antifouling property while maintaining a woody feeling, there is a method of using fluorine-based fine particles together with a curable binder resin. It is proposed but does not describe durability.

On the other hand, fluorine-based polymers have been conventionally used for water-repellent / oil-repellent treatment of fibers or so-called waterproof spray. In such applications, generally,
In order to exhibit highly durable water repellency and oil repellency, it is preferable to use a solvent type.
In order to obtain a fluorine-based polymer having excellent oil repellency, it is necessary to have a high fluorine content. In this case, the solvent that can be dissolved is limited to CFC having a high ozone destruction coefficient. Due to such problems of chlorofluorocarbons, and further restrictions on the base material and processing equipment, water-based fluorinated emulsions or non-aqueous emulsions dispersed in a hydrocarbon-based solvent are currently used. The development of is ongoing.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to protect the surface of a water-absorbing substance such as wood, paper and fiber without impairing the feel of the substrate, and to provide waterproof, stain-proof and weather-resistant properties. Is to provide a processing method that improves the performance.

[0007]

Means for Solving the Problems In view of the above situation, the present inventors have made intensive studies and found that an ethylenically unsaturated monomer (A) having a fluorinated alkyl group and soluble in alcohols It has been found that these problems can be solved by using the polymer (I) containing as a polymerization component, and the present invention has been completed.

As described above, a solvent system is advantageous in achieving sufficient waterproofness, antifouling property, and weather resistance. For this purpose, a fluorocarbon solvent having a high ozone destruction coefficient or an expensive special solvent is used. Must be used. As a solution to this,
Attempts have been made to use aqueous or non-aqueous emulsions. However, problems such as insufficient permeability to the base material due to the high surface tension occur, and it is a reality that sufficient performance as a solvent system is not obtained.

Accordingly, the present inventors have focused on alcohol as a solvent which is inexpensive, can be used for general purposes, and is sufficiently environmentally friendly, and can be uniformly dissolved in alcohol and sufficiently waterproof by using the method described below. A polymer (I) having water resistance, antifouling property and weather resistance has been found.

That is, the present invention relates to an ethylenically unsaturated monomer having a fluorinated alkyl group in the molecule and soluble in alcohol, preferably an ethylenically unsaturated monomer having two or more fluorinated alkyl groups. A polymer (I) obtained by polymerizing an ethylenically unsaturated monomer (B) having (A) as an essential component and preferably having a polysiloxane chain is preferably applied to a water-absorbing substance, preferably wood. To provide a surface treatment method for a water-absorbing substance.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The alcohol used as a solvent in the present invention is not particularly limited. For example, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-
Butyl alcohol, isobutyl alcohol and the like can be mentioned. Among these, ethyl alcohol and isopropyl alcohol are preferred in view of the solubility, performance and drying properties of the polymer (I).

The method for solubilizing the polymer (I) in alcohol is not particularly limited. For example, in an alcohol solution, one or more kinds of monomers having the monomer (A) as an essential component may be polymerized, or the polymer may be polymerized in a solution other than alcohol and then solubilized in alcohol. After polymerization by a known polymerization method other than solution polymerization, for example, a method such as bulk polymerization, emulsion polymerization, or suspension polymerization, it may be solubilized in alcohol.

In the present invention, the ethylenically unsaturated monomer (A) having a fluorinated alkyl group, which is an essential polymerization component in the polymer (I), is applied to a water-absorbing substrate and then waterproofed. Properties, antifouling properties and weather resistance can be improved. The monomer (A) is not particularly limited, and examples thereof include the following compounds.

A-1-1 CH ₂ = CHCOOCH ₂ CF ₃ A-1-2 CH ₂ = CHCOOCH ₂ CF ₂ CF ₃ A-1-3 CH ₂ = CHCOOCH ₂ CFHCF ₃ A-1-4 CH ₂ = C (CH ₃ ) COOCH ₂ CFHCF ₃ A-1-5 CH ₂ = CHCOOCH ₂ CH ₂ CF ₃ A-1-6 CH ₂ = CHCOOCH ₂ CF ₂ CFHCF ₃ A-1-7 CH ₂ = CHCOOCH ₂ CF (CF ₃ ) CF ₃ A-1-8 CH ₂ = CHCOOCH (CF ₃ ) ₂ A-1-9 CH ₂ = C (F) COOCH (CF ₃ ) ₂ A-1-10 CH ₂ = C (CH ₃ ) COOCH ( CF ₃ ) ₂ A-1-11 CH ₂ = CHCOOCH ₂ (CF ₂ CF ₂ ) ₂ H A-1-12 CH ₂ = C (F) COOCH ₂ (CF ₂ CF ₂ ) ₂ H A-1-13 CH ₂ = C (CH ₃ ) COOCH ₂ (CF ₂ CF ₂ ) ₂ H A-1-14 CH ₂ = CHCOOCH ₂ CF ₂ CF ₂ CFHCF ₃ A-1-15 CH ₂ = CHCOOCH ₂ CF ₂ CF ₂ H A- 1-16 CH ₂ = C (CH ₃ ) C00CH ₂ CF ₂ CF ₂ H A-1-17 CH ₂ = C (F) C00CH ₂ CF ₂ CF ₂ H A-1-18 CH ₂ = CHCOOCH ₂ CH ₂ C ₈ F ₁₇ A-1-19 CH ₂ = C (CH ₃ ) COOCH ₂ CH ₂ C ₈ F ₁₇ A-1-20 CH ₂ = CHCOOCH ₂ CH ₂ C ₁₂ F ₂₅ A-1-21 CH ₂ = C ( CH ₃ ) COOCH ₂ CH ₂ C ₁₂ F ₂₅ A-1-22 CH ₂ = CHCOOCH ₂ CH ₂ C ₁₀ F ₂₁ A-1-23 CH ₂ = C (CH ₃ ) COOCH ₂ CH ₂ C ₁₀ F ₂₁ A- 1-24 CH ₂ = CHCOOCH ₂ CH ₂ C ₆ F ₁₃ A-1-25 CH ₂ = C (CH ₃ ) COOCH ₂ CH ₂ C ₆ F ₁₃ A-1-26 CH ₂ = CHCOOCH ₂ CH ₂ C ₄ F ₉ A-1-27 CH ₂ = C ( F) COOCH ₂ CH ₂ C ₆ F ₁₃ A-1-28 CH ₂ = CHCOOCH ₂ (CH ₂ ) ₆ CF (CF ₃ ) ₂ A-1-29 CH ₂ = CHCOOCH ₂ (CF ₂ ) ₆ H A-1 -30 CH ₂ = CHCOOCH ₂ (CF ₂ ) ₈ H A-1-30 CH ₂ = C (CH ₃ ) COOCH ₂ (CF ₂ ) ₈ H A-1-31 CH ₂ = CHCOOCH ₂ (CF ₂ ) ₁₀ H A-1-32 CH ₂ = CHCOOCH ₂ (CF ₂ ) ₁₂ H A-1-33 CH ₂ = CHCOOCH ₂ C (OH) HCH ₂ C ₈ F ₁₇ A-1-34 CH ₂ = CHCOOCH ₂ CH ₂ N ( C ₃ H ₇ ) SO ₂ C ₈ F ₁₇ A-1-35 CH ₂ = CHCOOCH ₂ CH ₂ N (C ₂ H ₅ ) COC ₇ F ₁₅ A-1-36 CH ₂ = CHCOO (CH ₂ ) ₂ (CF ₂ ) ₈ CF (CF ₃ ) ₂ Of course, the present invention is not limited by these exemplified compounds. As the monomer (A), only one type may be used, or two or more types may be used. The amount of the monomer (A) introduced into the polymer (I) varies depending on the required level of performance, but is preferably 5 to 90% by weight, and more preferably 30 to 80% by weight.

In order to produce a polymer (I) using such a monomer (A) and obtain sufficient performance such as waterproofness, the fluorine content in the polymer (I) is increased. There must be.

In order to solubilize the polymer (I) in alcohol while maintaining sufficient performance, three methods can be proposed. The first method is to use an ethylenically unsaturated monomer having two or more fluorinated alkyl groups in the molecule for at least one kind of the monomer (A). If such a type of monomer (A) is used, sufficient performance can be realized with a much smaller fluorine content than a monomer having only one fluorinated alkyl group in the molecule. That is, when using an ethylenically unsaturated monomer having two or more fluorinated alkyl groups in the molecule, 0.1%
It is preferably from 70 to 70% by weight, and more preferably from 1 to 50% by weight. Therefore, it can be easily solubilized in alcohol. Examples of such type of monomer (A) include the following compounds.

[0017]

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[0018]

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[0019]

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[0020]

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[0021]

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[0022]

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[0023]

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[0024]

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[0025]

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[0026]

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[0027]

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[0028]

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[0029]

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The present invention is, of course, not limited by these exemplified compounds. The second method of solubilizing in alcohol is a method of incorporating a functional group having an alcohol-philic property to be solubilized in alcohol into the polymer (I). Examples of such an alcohol-philic functional group include a hydroxyl group, a carboxyl group, a sulfonyl group, a phosphoric acid group, an amino group, an amide group, and an ethylene glycol chain. There is no particular limitation on the method of incorporating the alcohol-philic functional group into the polymer (I). The monomer (A) may be copolymerized with an ethylenically unsaturated monomer having an alcoholic functional group, or a functional group that reacts with the compound having an alcoholic functional group may be previously used. Introduced during coalescence (I), then
It may be allowed to react with a compound having an alcoholic functional group. Here, the functional group which reacts with the compound having the alcohol-philic functional group may be present in other parts of the monomer (A).

Taking into account the realistic reaction process and productivity,
The method using an ethylenically unsaturated monomer having an alcoholic functional group is the simplest. Examples of the ethylenically unsaturated monomer having an alcoholic functional group include the following compounds.

That is, α, β-ethylenically unsaturated carboxylic acid, that is, monovalent or divalent carboxylic acid such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, and carbon number of (meth) acrylic acid 1 to 18 hydroxyalkyl esters, i.e., 2-hydroxyethyl ester, 2-hydroxypropyl ester, 4-hydroxybutyl ester, etc .;
Examples include a monomer containing a repeating unit such as propylene oxide, that is, a poly (alkylene oxide). Commercially available products of this compound include NK esters M-20G, M-40G, M-90G, and M-N, manufactured by Shin-Nakamura Chemical Co., Ltd.
-230G, M-450G, AM-90G, 1G, 2
G, 3G, 4G, 9G, 14G, 23G, 9PG, A-
200, A-400, A-600, APG-400, A
PG-700, Blemmer PE-9 manufactured by NOF Corporation
0, PE-200, PE-350, PME-100, P
ME-200, PME-400, PME-4000, P
P-1000, PP-500, PP-800, 70FE
P-350B, 55PET-800, 50POEP-8
00B, NKH-5050, PDE-50, PDE-1
00, PDE-150, PDE-200, PDE-40
0, PDE-600, AP-400, AE-350, A
DE-200, ADE-400 and the like.

Other examples of the ethylenically unsaturated monomer having an alcohol-philic functional group include 2- (meth) acryloyloxyethylsuccinic acid and 2-acrylamide-
2-methylpropanesulfonic acid, partially sulfonated styrene, mono (acryloyloxyethyl) acid phosphate, mono (methacryloxyethyl) acid phosphate, dibutyl fumarate, dimethyl fumarate, N-isopropylacrylamide And the like.

It is needless to say that the present invention is not limited by the above specific examples. A third method for solubilizing in alcohol is a method for adjusting the optimum molecular weight of the polymer (I). This is because the solubilized molecular weight varies depending on the composition of the polymer (I) as described above. In general, low fluorine content, low molecular weight, easy to solubilize, but sufficient water resistance,
Antifouling property and weather resistance are not obtained, and even if initial performance is obtained, durability is often poor.

In the present invention, the optimum molecular weight varies depending on the first and second methods or the balance with other components in the polymer (I), but the number average molecular weight is 500 to 500.
Suitably it is between 100,000 and preferably between 1,000 and 30,000.

In the polymer (I), various compounds can be introduced according to the purpose. In particular, in order to improve the antifouling property, together with the monomer (A), a polysiloxane is used. It is effective to use an ethylenically unsaturated monomer (B) having a chain. As the ethylenically unsaturated group of the monomer (B), any of a vinyl group, an acryloyl group, and a methacryloyl group can be used, but an acryloyl group or a methacryloyl group is preferable from the viewpoint of polymerization reactivity. Examples of the monomer (B) include the following.

[0037]

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[0038]

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[0039]

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However, both Me and Ph represent a methyl group and a phenyl group, respectively. It should be noted that the present invention is of course not limited by the above specific examples. As the other components in the polymer (I), any known and publicly known components can be used, and the copolymerizability with the monomer (A), the properties of the target base material, Is selected according to the performance required. Specific examples of these are as follows.

That is, fatty acids such as styrene, nuclear-substituted styrene, acrylonitrile, vinyl chloride, vinylidene chloride, vinyl pyridine, N-vinyl pyrrolidone, vinyl sulfonic acid, and vinyl acetate; and α, β-ethylenically unsaturated carboxylic acids. As a derivative, a (meth) acrylic acid alkyl ester having an alkyl group having 1 to 18 carbon atoms (hereinafter, this expression is a general term for both acrylic acid alkyl ester and methacrylic acid alkyl ester), that is, (meth) Acrylic acid methyl, ethyl, propyl, butyl, octyl, 2-ethylhexyl, decyl, dodecyl, stearyl ester and the like, and (meth) acrylic acid having 1 to 18 carbon atoms, such as aminoalkyl ester, ie, dimethylaminoethyl ester, diethylaminoethyl ester , Diethylami Nopropyl ester and the like. The (meth) acrylic acid has 3 to 18 carbon atoms.
Ether oxygen-containing alkyl esters such as methoxyethyl ester, ethoxyethyl ester, methoxypropyl ester, methylcarbyl ester, ethylcarbyl ester, butylcarbyl ester and the like, and alkyl vinyl ethers having 1 to 18 alkyl carbon atoms such as methyl vinyl ether and propyl Examples thereof include vinyl ether, dodecyl vinyl ether, and the like, and macromonomers such as styrene macromonomer 4500 manufactured by Sartomer and MMA macromonomer manufactured by Toagosei Co., Ltd.

The present invention is, of course, not limited to the above specific examples. It is also possible to introduce an ethylenically unsaturated monomer having a bridging group having a high glass transition point. When such a monomer is introduced, the polymer (I) has a high glass transition point and contributes to the durability of the perfluoroalkyl group. Examples of the ethylenically unsaturated monomer having a bridging group include dicyclopentanyloxylethyl (meth) acrylate, isobornyloxylethyl (meth) acrylate, isobornyl (meth) acrylate, adamantyl (meth) acrylate, Dimethyl adamantyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate and the like can be mentioned.

In order to improve the weather resistance, it is also possible to use an ethylenically unsaturated monomer having a light or heat stable functional group. Commercially available products of such compounds include FA-711M, FA-712HM (manufactured by Hitachi Chemical), and UVA-93 (manufactured by Otsuka Chemical).

Further, a silane coupling agent having an ethylenically unsaturated group such as γ-methacryloxypropyltrimethoxysilane can be used as a monomer in order to improve the adhesion to the substrate.

It is needless to say that the present invention is not limited by the above specific examples. The method for producing the polymer (I) comprising the monomer (A) according to the present invention as an essential component is not particularly limited, and any known method, that is, polymerization such as radical polymerization, cationic polymerization, or anionic polymerization, may be used. On the basis of the mechanism, it can be produced by a solution polymerization method, a bulk polymerization method, an emulsion polymerization method, or the like. Among these methods, the radical polymerization method is particularly simple and industrially preferable. In this case, as the polymerization initiator, those known in the art can be used. As the polymerization initiator, for example, benzoyl peroxide, peroxides such as diacyl peroxide, azobisisobutyronitrile, azo compounds such as phenylazotriphenylmethane,
Metal chelate compounds such as Mn (acac) 3;

If necessary, lauryl mercaptan,
2-mercaptoethanol, ethylthioglycolic acid,
A chain transfer agent such as octylthioglycolic acid;
A thiol compound containing a coupling group such as mercaptopropyltrimethoxysilane can be used in combination with a chain transfer agent. According to the findings of the present inventors, the use of such a coupling group-containing chain transfer agent can improve the adhesion to a substrate and the durability as a coating agent. The fluorine-based random or block copolymer according to the present invention can also be obtained by photopolymerization in the presence of a photosensitizer or a photoinitiator, or polymerization using radiation or heat as an energy source.

The polymerization can be carried out in the presence or absence of a solvent, but is preferably carried out in the presence of a solvent from the viewpoint of workability. Examples of the solvent include alcohols such as ethyl alcohol and isopropyl alcohol; ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; esters such as methyl acetate, ethyl acetate and butyl acetate; polar solvents such as dimethyl formamide and dimethyl sulfoxide; Halogen solvents such as 1,1,1-trichloroethane and chloroform; ethers such as tetrahydrofuran and dioxane; aromatics such as benzene, toluene and xylene; and perfluorooctane and perfluorotri-n-.
Examples thereof include fluorinated inert liquids such as butylamine, and any of these can be used.

When the polymer (I) according to the present invention is coated on a substrate, a coupling agent such as a silane-based, titanium-based, or zirco-aluminate-based coupling agent is used for the purpose of improving the adhesion to the substrate. They can be used together. Among these, dimethyldimethoxysilane, dimethyldiethoxysilane, methyltrimethoxysilane, dimethylvinylmethoxysilane,
Phenyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, γ-
Silane-based coupling agents such as glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, and γ-mercaptopropyltrimethoxysilane are particularly preferred. Further, a fluorine atom-containing alkoxysilane compound and a fluorine atom-containing titanium acylate Compound,
A fluorine-based coupling agent such as a fluorine atom-containing alkoxyzirconium compound can also be used.

The present invention is, of course, not limited by the above-described specific examples. Further, if necessary, it can be used in combination with one or more publicly known and used polymers. Such polymers include acrylic resins,
Examples thereof include urethane resins, alkyd resins, phenol resins, epoxy resins, polyester resins, and fluororesins, but of course these do not limit the present invention.

Further, if necessary, pigments, dyes,
Colorants such as bon; inorganic powders such as silica, titanium oxide, zinc oxide, aluminum oxide, zirconium oxide, calcium oxide, and calcium carbonate; higher fatty acids; poly (vinylidene fluoride); poly (tetrafluoroethylene); Various fillers such as an organic fine powder and a light resistance improver and a weather resistance improver can be appropriately added.

The method of applying the polymer (I) according to the present invention to a substrate is not particularly limited, and any known method can be used. For example, impregnation, dipping, spray coating, brush coating, gravure coating and the like can be mentioned, but it goes without saying that the present invention is not limited by such specific examples.

It is also possible to carry out a pretreatment before applying the polymer (I) in consideration of the expected effects and the workability during coating. As a pretreatment method, a resin serving as a primer, for example, an acrylic resin, a urethane resin, an alkyd resin, a phenol resin, an epoxy resin,
A method of applying a polyester resin, a fluororesin, or the like, a method of irradiating the substrate with an energy beam such as plasma, or a method of polishing by sanding or the like may be used.

It should be noted that the present invention is not limited to the above-mentioned specific examples. The absorbent material according to the present invention is not particularly limited as long as it has a water-absorbing substrate, but various types of wood, paper, cotton, hemp, wool, nylon,
Polyester, polyvinyl alcohol epoxy resin and the like can be mentioned. The present invention is particularly excellent in surface treatment of wood.

The present invention is, of course, not limited to the above specific examples.

[0055]

EXAMPLES Next, reference examples, examples and comparative examples will be given in order to explain the present invention in more detail. However, it is needless to say that the present invention is not limited by these descriptions. “Parts” in the text are based on weight unless otherwise specified.

Reference Example 1 (Synthesis of Fluorine Copolymer) In a glass flask equipped with a stirrer, a condenser and a thermometer, 40 parts by weight of a fluorine monomer A-1-18, B-1
0, 5 parts by weight, NK ester M-230G (manufactured by Shin-Nakamura Chemical Co., Ltd.) 45 parts by weight, 2-hydroxylethyl methacrylate (hereinafter abbreviated as 2-HEMA) 5 parts by weight, methyl methacrylate (hereinafter, referred to as methyl methacrylate) , MMA) 5
Parts by weight, and methyl isobutyl ketone (hereinafter, MIB)
233 parts by weight) were charged, and 1.5 parts by weight of azoisobutyronitrile (hereinafter abbreviated as AIBN) as a polymerization initiator and 0.7 parts of lauryl mercaptan as a molecular weight regulator were added under a nitrogen gas stream and reflux. After adding parts by weight, 8
The reaction was continued at 5 ° C. for 11 hours to complete the polymerization.

Then, using an evaporator and a hot air drier, MIBK was scattered (solid content: 98% or more), and the obtained product was dissolved in IPA at a concentration of 20% by weight to obtain a pale yellow transparent uniform liquid. I got

The number average molecular weight in terms of polystyrene of the polymer measured by gel permeation chromatography (hereinafter abbreviated as GPC) was Mn = 5,100. (This copolymer is referred to as polymer 1.) Reference Examples 2 to 6 Various fluorine-containing monomers (A) as essential components in other monomers and solvents shown in Table 1 under the conditions shown in Reference Example 1. Copolymerization was performed under the same conditions to obtain polymers 2 to 6. Regarding those polymerized in a solvent other than alcohol, the same treatment as in Reference Example 1 was performed to finally obtain an alcohol solution.

[0059]

[Table 1]

The compound names of the commercial products in the table are as follows. M-230G: NK ester M-230G, methoxypolyethylene glycol methacrylate [manufactured by Shin-Nakamura Chemical Industry Co., Ltd.] M-90G: NK ester M-90G, methoxypolyethylene glycol methacrylate [manufactured by Shin-Nakamura Chemical Industry Co., Ltd.] PE-350: Blenmer PE-350, polyethylene glycol methacrylate [manufactured by NOF Corporation] FA-711M: Fancryl FA-711M, 1,
2,2,6,6-pentamethylpiperidinyl methacrylate [manufactured by Hitachi Chemical Co., Ltd.] RUVA: RUVA-93, 2 (2′-hydroxy 5 ′)
-Methacryloxyethylphenyl) 2H benzotriazole [manufactured by Otsuka Chemical Co., Ltd.] EtOH: ethyl alcohol Table 1 shows the alcohol and solution used in the final solvent together with the amount of monomer, solvent and lauryl mercaptan used in the polymerization. And the number average molecular weight in terms of polystyrene are shown together.

The surface protection of the hinoki material was carried out using each of the polymers shown in Examples 1 to 5 and Comparative Examples 1 and 2. In each alcohol solution having a solid content concentration of 20% by weight shown in the reference example, a solution polymerized in an alcohol solvent was diluted to 20% by weight with the same type of alcohol.
The sample was impregnated with a hinoki material of × 60 × 30 mm, pulled up, and dried at 110 ° C. for 10 minutes to obtain a sample.

Each sample was placed under the condition of a black panel temperature of 63 ° C. using a sunshine weather meter.
After 00 and 1000 hours, the following physical properties were measured. As an evaluation of the waterproofness of the sample, the weight change before and after the weathering test was measured, and the water absorption was calculated by the following equation. In addition, the presence / absence of cracks considered to be caused by repeated water absorption / drying was also visually confirmed. As an evaluation of discoloration, a color difference (ΔE) was measured.

For the evaluation of the antifouling property, the sample was exposed outdoors for 3 months, and the change in color difference (ΔE) was compared with the initial value. Table 2
Shows the results of Examples 1 to 5 and Comparative Examples 1 and 2.

[0064]

[Table 2]

In Examples 1 to 5, Polymers 1 to 5 were used. In Example 6, Polymer 4 was mixed with a weathering stabilizer as follows. [Blending] 20% ethanol solution of polymer 4 100 (parts by weight) Sanol LS-765 0.6 Chemisorb 74 0.6 Irganox 1010 0.06 Sanol LS-765: Hindered amine light stabilizer manufactured by Sankyo Co., Ltd. Chemisorb 74: a benzotriazole-based UV absorber manufactured by Chemipro Kasei Co., Ltd. Irganox 1010: an antioxidant and heat-resistant stabilizer manufactured by Ciba-Geigy Co., Ltd. Further, Comparative Example 1 is a polymer 6 and Comparative Example 2 is a general-purpose fluorine. Acrylic emulsion was used.

[0066]

By applying the alcohol-soluble polymer to the water-absorbing substance, it is possible to improve the waterproofness, antifouling property, weather resistance and the like of the absorbent substance.

Claims (5)

[Claims] 1. A method for applying a polymer (I) having a fluorinated alkyl group in the molecule and comprising an ethylenically unsaturated monomer (A) soluble in alcohol as a polymerization component to a water-absorbing substance. A method for treating a surface of a water-absorbing substance, comprising: 2. The monomer (A) has two fluorinated alkyl groups.
The method according to claim 1, which is an ethylenically unsaturated monomer having at least one unsaturated monomer. 3. An ethylenically unsaturated monomer (B) having a polysiloxane chain as a polymerization component of the polymer (I).
3. The method according to claim 1, wherein 4. The method according to claim 1, wherein an ethylenically unsaturated monomer having a bridging group is further used as a polymerization component of the polymer (I). 5. The method according to claim 1, wherein the water-absorbing substance is wood.