JP2008285556A - Curable composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a curable composition excellent in elasticity and flexibility of a cured product and further, excellent in hydrophilic property and thus scarcely causing contamination with the lapse of time. <P>SOLUTION: The curable composition comprises 100 pts.wt. acrylic polymer, in which the main chain is an acrylic polymer, having at least one kind of polar functional group selected from a group consisting of a hydroxy group, a carboxyl group, an amino group and a sulfonic group and a hydrolyzable reactive silicon group, and 1-5 pts.wt. curing catalyst for carrying out moisture curing of the acrylic polymer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a curable composition that provides a cured product having a hydrophilic surface, and more specifically, a curable composition that can provide a cured product that requires flexibility such as a sealing material and an elastic adhesive. About.

  In a building, it is required that the building exterior material and the coating on the outer wall of the building are not contaminated and are beautiful. Dust and dust in the atmosphere adhere to the roof and outer wall of the building in fine weather and run down the outer wall by rainwater. When dust or dust completely flows down due to rain water, the outer wall is hard to get dirty, but some dust or dust remains attached to the outer wall. Moreover, dust and dirt are also contained in rainwater, and dust and dirt in rainwater may adhere to the outer wall and cause dirt. Therefore, the outer wall of the building must be gradually soiled over time.

  The dirt on the outer wall of the building and the paint film on the surface of the building material are composed of combustion products such as carbon black, or inorganic pollutants such as urban dust and viscous particles. Conventionally, in order to prevent such contamination, it has been considered preferable to coat the outer wall surface with a water-repellent paint.

  However, in recent years, since urban dust contains a lot of hydrophobic components, it has been considered preferable that the coating surface be as hydrophilic as possible. When the hydrophilicity is increased, the contact angle of the coating film surface with water becomes small. The contact angle with respect to water in a general coating film was 50 ° or more, and it did not have sufficient hydrophilicity.

  On the other hand, in the recent superhydrophilic technology using the photocatalytic technology, the hydrophilicity is greatly enhanced by arranging a large number of hydroxyl groups on the surface of the coating film. However, since the photocatalyst decomposes organic substances, the photocatalyst must be held by the inorganic compound layer.

On the other hand, Patent Document 1 below discloses a coating composition with improved hydrophilicity. Here, it is a coating composition containing an organosilicate and / or a condensate thereof, and the contact angle with water is 70 ° or less. By adding organosilicate to the organic coating composition, a large number of hydroxyl groups can be present on the surface of the coating film, thereby improving the hydrophilicity. In this method, the hydrophilicity cannot be increased as much as when the superhydrophilic technology is used, but the hydrophilicity can be increased without decomposing the organic layer.
Patent No. 2869443

  As described above, in order to prevent contamination of the coating film surface on the outer wall of a building, a superhydrophilic treatment method using a photocatalytic technique and a method using origanosilicate as described in Patent Document 1 have been proposed. And by these methods, the outer wall is prevented from being soiled.

  However, the application of photocatalyst technology and technology using organic silicate has not progressed for sealing materials used for joints on the outer walls of buildings. In other words, contamination prevention technology by hydrophilization treatment using a photocatalyst or organic silicate is effective for paints that do not require flexibility such as elongation, but for sealing materials and elastic adhesives that require elongation and flexibility. Was difficult to use.

  Therefore, in the conventional sealing material, the contact angle with respect to water was about 90 °. Therefore, the coating material is further applied to the surface of the sealing material to cover the surface of the sealing material, thereby preventing contamination. However, when the surface of a sealing material excellent in elongation and flexibility is coated with a paint, the coating film is not sufficiently flexible and does not have sufficient adhesive strength, so the surface may crack or the coating film may peel off. there were.

  The object of the present invention is to provide a cured product that is excellent in elongation and flexibility, and has improved hydrophilicity on the surface of the cured product, and is used as a sealing material for the outer wall of a building. It is an object of the present invention to provide a curable composition that is hardly contaminated by dust or the like.

  According to the present invention, it has at least one polar functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and a sulfone group, and a hydrolyzable reactive silicon group, and the main chain is an acrylate-based heavy group. There is provided a curable composition comprising 100 parts by weight of an acrylic polymer as a coalescence and 1 to 5 parts by weight of a curing catalyst for moisture curing the acrylic polymer.

  In the curable composition concerning this invention, a hydroxyl group is preferable as said polar functional group. In the acrylic polymer having a hydroxyl group, the hydrophilicity is effectively enhanced by the presence of the hydroxyl group, and contamination due to dust containing a large amount of hydrophobic components is less likely to occur.

  In the curable composition according to the present invention, preferably, the contact angle of the cured product with water is 70 ° or less, and the elongation at break in the tensile test according to JIS K 6301 is 10% or more. Has sufficient hydrophilicity, is hardly contaminated by dust containing a hydrophobic component, and the cured product has sufficient elongation characteristics, and therefore has excellent flexibility. Therefore, for example, the curable composition according to the present invention is suitably used as a sealing material or an elastic adhesive.

  Details of the present invention will be described below.

(Acrylic polymer)
The acrylic polymer in the present invention has a hydrolyzable reactive silicon group in the molecule, thereby being cured by moisture to give a cured product. The acrylic polymer has at least one polar functional group among a hydroxyl group, a carboxyl group, an amino group, and a sulfone group. The presence of this polar functional group increases the hydrophilicity of the cured product.

  As the acrylic monomer used to obtain the acrylic polymer, one or more (meth) acrylic acid or (meth) acrylic acid ester is used. Although it does not specifically limit as said (meth) acrylic acid ester, (meth) acrylic acid methyl, (meth) acrylic acid methyl, (meth) acrylic acid ethyl, (meth) acrylic acid n-propyl, (meth) acrylic acid Isopropyl, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, n-hexyl (meth) acrylate, (meth) acrylic acid Cyclohexyl, n-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, isobornyl (meth) acrylate, (meth ) Benzyl acrylate, phenyl (meth) acrylate, stear (meth) acrylate Le, and the like (meth) acrylic acid dimethylaminoethyl, and the like.

  The acrylic polymer is obtained by copolymerizing the (meth) acrylic acid or (meth) acrylic ester and an appropriate monomer copolymerizable with the (meth) acrylic acid or (meth) acrylic ester. The main chain is an acrylic copolymer.

  Such a copolymerizable monomer is not particularly limited, and examples thereof include a vinyl ester monomer and / or a styrene monomer. Examples of vinyl ester monomers include vinyl acetate, vinyl formate, vinyl propionate, vinyl butyrate, vinyl n-caproate, vinyl isocaproate, vinyl octoate, vinyl laurate, vinyl palmitate, vinyl stearate, vinyl trimethyl acetate, and pival. Examples include vinyl acid vinyl, vinyl chloroacetate, vinyl trichloroacetate, vinyl trifluoroacetate, and vinyl benzoate.

  Styrene monomers include styrene, α-methyl styrene, p-methyl styrene, m-methyl styrene, o-methyl styrene, 2,4-dimethyl styrene, 2,5-dimethyl styrene, p-ethyl styrene, p-isopropyl. Styrene, p-chloromethyl styrene, p- (2-chloroethyl) styrene, etc. are mentioned.

  As for the said vinyl-type monomer and / or a styrene-type monomer, only 1 type may be used and 2 or more types may be used together.

  In addition, although the curable composition concerning this invention is used for an elastic adhesive agent, a sealing material, or a coating material, it is desirable that the glass transition temperature Tg of the said acrylic polymer is sufficiently lower than environmental temperature. Therefore, the acrylic polymer desirably has a copolymer composition in which Tg is in the range of −80 to −20 ° C.

  In obtaining the acrylic polymer, a monomer having a polar functional group is preferably used in order to introduce the polar functional group described above. That is, at least one monomer having at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and a sulfone group is copolymerized. Examples of such monomers include (meth) acrylic acid and salts thereof, 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl acrylate, acrylamide, and the like.

  More preferably, a monomer having a hydroxyl group is preferably used as the monomer because the hydrophilicity can be effectively increased, and a hydroxyl group-containing monomer such as 4-hydroxybutyl acrylate is used as such a monomer. .

  Further, in order to introduce the hydrolyzable reactive silicon group, in obtaining the acrylic polymer, the reactive silicon group-containing compound is copolymerized or reacted with an acrylic monomer such as the (meth) acrylic acid ester. . Examples of such reactive silicon group-containing compounds include 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3 -An appropriate carboxysilane such as mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane or the like can be used. As for the said reactive silicon group containing compound, only 1 type may be used and 2 or more types may be used together.

  The polymerization initiator for the polymerization for obtaining the acrylic polymer is not particularly limited, but a peroxide polymerization initiator or an azo polymerization initiator can be appropriately used, and has an appropriate 10-hour half-life temperature. A polymerization initiator may be selected.

  Specific examples of such a polymerization initiator include organic peroxide polymerization initiators such as benzoyl peroxide, di-t-butyl peroxide, cumene hydroperoxide, and t-butyl peroxybenzoate; Examples include radical polymerization initiators such as azo polymerization initiators such as 2,2′-azobis (2-methylbutyronitrile) and 2,2′-azobiscyclohexanecarbonitrile, but are not particularly limited. .

(Curing catalyst)
The curing catalyst used in the present invention is blended to accelerate the moisture curing reaction of the acrylic polymer having the reactive silicon group. As the curing catalyst, a silanol condensation catalyst that has been conventionally used as a curing catalyst for curing a reactive silicon group-containing acrylic polymer can be suitably used. Examples of such curing catalysts include, for example, dibutyltin dilaurate, bis (dibutyltin lauric acid) oxide (for example, trade name SB-65, manufactured by Sansha Kikai Co., Ltd.), dibutyltin oxide, dibutyltin diacetate, Tin compounds such as dibutyltin phthalate, dibutyltin bisacetylacetonate, dibutyltin bis (monoester malate), tin octylate, dibutyltin octoate, dioctyltin oxide; tetra-n-butoxy titanate, tetraisopropoxy titanate, etc. Examples thereof include titanate compounds; amine salts such as dibutylamine-2-ethylhexoate; and other acidic catalysts and basic catalysts. Only one type of curing catalyst may be used, or two or more types may be used in combination.

  Further, as a co-catalyst for further enhancing the curability, silane compounds and amine compounds, such as ketoxime silane; alkoxy silane; amino group-substituted alkoxy silane such as aminoxy silane and amido silane; lauryl amine or derivatives thereof May be further blended.

  The blending ratio of the curing catalyst is in the range of 1 to 5 parts by weight with respect to 100 parts by weight of the acrylic polymer. If it is less than 1 part by weight, the moisture curing reaction does not proceed sufficiently, and dirt may be easily attached. If the amount exceeds 5 parts by weight, the effect of accelerating the curing reaction cannot be further increased even if the amount of the curing catalyst is increased further, or the reaction proceeds at the time of product storage due to premature reaction, resulting in an extremely short product life. , Curing during product use may be too early and difficult to use.

(Other ingredients)
In the curable composition according to the present invention, in addition to the acrylic polymer and the curing catalyst, an adhesion-imparting agent, a dehydrating agent, a plasticizer, a sagging inhibitor, a filler, an expansion inhibitor, an antioxidant, an ultraviolet absorber, An appropriate additive such as a pigment, a fragrance or a solvent can be added as necessary.

  Examples of the adhesion-imparting agent include compounds having an amino group and an alkoxysilyl group in one molecule, such as 3-aminopropyltrimethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- (2-aminoethyl) -3-aminopropyltriethoxysilane N, N′-bis- [3- (trimethoxysilyl) propyl] ethylenediamine, N, N′-bis- [3- (triethoxysilyl) propyl] ethylenediamine, N, N′-bis- [3- ( Methyldimethoxysilyl) propyl] ethylenediamine, N, N′-bis- [3- (trimethoxy Ryl) propyl] hexamethylenediamine, N, N′-bis- [3- (triethoxysilyl) propyl] hexamethylenediamine, N, N′-bis- [3- (methyldimethoxysilyl) propyl] hexamethylenediamine, N, N-bis- [3- (trimethoxysilyl) propyl] ethylenediamine, N, N-bis- [3- (methyldimethoxysilyl) propyl] ethylenediamine, N, N-bis- [3- (triethoxysilyl) Propyl] ethylenediamine, N, N-bis- [3- (trimethoxysilyl) propyl] hexamethylenediamine, N, N-bis- [3- (methyldimethoxysilyl) propyl] hexamethylenediamine, N, N-bis- [3- (Triethoxysilyl) propyl] hexamethylenediamine, N, N-bis- [3 (Trimethoxysilyl) propyl] amine, N, N-bis - [3- (triethoxysilyl) propyl] amine, N, N-bis - [3- (methyldimethoxysilyl) propyl] amine. Only 1 type may be used for an adhesive imparting agent, and 2 or more types may be used together.

  The dehydrating agent is used to remove intruded moisture during storage of the reactive silicon group-containing acrylic polymer. Examples of the dehydrating agent include silane compounds such as vinyltrimethoxysilane, dimethyldimethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, and tetramethoxysilane; methyl orthoformate, ethyl orthoformate, and methyl orthoacetate. And hydrolyzable ester compounds such as ethyl orthoacetate. These may be used alone or in combination of two or more.

  The plasticizer is used for increasing the elongation of the cured product of the reactive silicon group-containing acrylic polymer and reducing the modulus. Examples of the plasticizer include phosphate esters such as tributyl phosphate and tricresyl phosphate; phthalate esters such as dioctyl phthalate; fatty acid monobasic esters such as glycerin monooleate; dibutyl adipate, dioctyl adipate, etc. And fatty acid dibasic acid esters; and polypropylene glycol. These may be used alone or in combination of two or more.

  The sagging inhibitor is used for sagging prevention of reactive silicon group-containing acrylic polymers, and examples thereof include hydrogenated castor oil, fatty acid bisamide, fumed silica, and the like.

  The filler is used for the purpose of reinforcing a reactive silicon group-containing acrylic polymer. Examples of the filler include calcium carbonate, magnesium carbonate, calcium oxide, hydrous silicic acid, anhydrous silicic acid, fine powder silica, calcium silicate, titanium dioxide, clay, talc, carbon black, glass balloon and the like. These may be used alone or in combination of two or more.

  Although it does not specifically limit as said solvent, Toluene, xylene, methanol, ethanol etc. are mentioned.

  The curable composition according to the present invention has at least one polar functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group, and a sulfone group, a hydrolyzable reactive silicon group, and a main chain. Since 100 parts by weight of the acrylic polymer composed of an acrylic polymer is blended in a proportion of 1 to 5 parts by weight of the curing catalyst, a cured product is obtained by the moisture curing reaction of the hydrolyzable reactive silicon group. . And since the said acrylic polymer has the said polar functional group, the hydrophilicity of hardened | cured material is improved, for example, the contact angle with respect to water can be 70 degrees or less. The cured product of the acrylic polymer is excellent in flexibility and elasticity. For example, the elongation at the time of cutting in a tensile test based on JIS K 6301 is 10% or more. It is possible to provide a curable composition suitable for a sealing material, an elastic adhesive, or a coating agent that requires elasticity, which is used as a joint material for the outer wall of a required building.

  Conventional sealing materials of this type have elasticity but are not sufficiently patrolable, so they have to be coated with a paint having excellent hydrophilicity, and the coating surface tends to crack or peel off. . On the other hand, when the curable composition of the present invention is used for such applications, the cured product itself of the curable composition is excellent in hydrophilicity, and thus it is not necessary to coat with a hydrophilic paint or the like. In addition, neither cracking nor peeling of the coating film occurs. Therefore, joints and the like on the outer wall of the building can be easily formed, and contamination of joints and the like can be reliably prevented.

  Hereinafter, the present invention will be clarified by giving specific examples and comparative examples of the present invention. In addition, this invention is not limited to a following example.

(Manufacture of polymers)
Polymers A to G were produced in the following manner.

  Production of Polymer A: As shown in Table 1 below, 63 parts by weight of acrylic acid, 25 parts by weight of 2-ethylhexyl acrylate (2EHA), KBM-502 (manufactured by Shin-Etsu Chemical Co., Ltd.) as a hydrolyzable reactive silicon group-containing monomer , 5 parts by weight of trade name, 3-methacryloxypropylmethyldimethoxysilane), 7 parts by weight of n-DDM (manufactured by Wako Pure Chemical Industries, Ltd.) and 1 part by weight of Solmic AP-7 (manufactured by Nippon Alcohol), and heated to boiling point Then, after refluxing for 30 minutes, Perhexa TMH (Nippon Yushi Co., Ltd. polymerization initiator) and Parroyl 355 (Nippon Yushi Co., Ltd. polymerization initiator) were respectively used as polymerization initiators in Table 3 after the time shown in Table 3 below. The indicated amount (unit: parts by weight) was added to carry out polymerization. After 7 hours from the start of the reaction, the flask was cooled to complete the polymerization reaction. In this way, Polymer A was obtained. As shown in Table 1 below, polymers B to G were obtained in the same manner as described above except that the raw materials used and the mixing ratio thereof were changed.

  In the production of polymer A, sodium hydroxide equivalent to acrylic acid was added to neutralize the carboxylic acid.

  Table 1 shows the number average molecular weight Mn and the molecular weight distribution Mw / Mn of the polymers A to G.

Example 1
As shown in Table 4 below, 1 part by weight of Neostan U-200 (manufactured by Nitto Kasei Co., Ltd., trade name: dibutyltin dilaurate) as a curing catalyst and 200 parts by weight of the polymer D obtained as described above, and light stability 1 part by weight of an agent (Ciba Geigy, trade name: Tinuvin 328), 1 part by weight of an ultraviolet absorber, Ciba Geigy, trade name: Tinuvin 765, and an antioxidant (Ciba Geigy, trade name: Irganox 1010) ) 1 part by weight and 100 parts by weight of calcium carbonate (manufactured by Shiraishi Calcium Co., Ltd., product number: White P-50) as a filler, and thoroughly mixed in a stirring defoaming device, the curability of Example 1 A composition was obtained.

(Examples 2-5 and Comparative Examples 1-3)
As shown in Table 4 below, a curable composition was obtained in the same manner as in Example 1 except that the type of polymer used and / or the blending amount of the curing catalyst was changed. In addition, Kaneka MS polymer 203 used in Comparative Example 1 is an acrylic-modified silicon polymer manufactured by Kaneka Corporation, an acrylic polymer having an acrylic polymer in the main chain and a hydrolyzable reactive silicon group. .

(Evaluation of Examples and Comparative Examples)
(A) Preparation of sample for elongation test The curable composition obtained by sufficiently stirring and mixing with the above stirring and defoaming apparatus and defoaming was placed in a 2 mm thick mold and decompressed with a vacuum dryer. While the polymerization solvent was volatilized. Thereafter, it was maintained in a room at 23 ° C. and 50% relative humidity for 2 weeks to obtain a sample for curability and elongation test.

(B) Preparation of Sample for Contaminating Water Contact Angle Test The curable composition obtained by sufficiently stirring and mixing with the stirring and defoaming apparatus and defoaming is made into a glass plate with a doctor blade to a thickness of 50 μm. And then dried in a gear oven at a temperature of 110 ° C. for 3 minutes, volatilizes the polymerization solvent, and then cured in a room at 23 ° C. and a relative humidity of 50% for 2 weeks, for contamination and water contact angle tests. A sample was obtained. In Comparative Example 1, the polymerization solvent was not included, but it was dried in a gear oven at a temperature of 110 ° C. for 3 minutes as in Examples 1 to 5 and Comparative Examples 2 and 3.

(Measurement of elongation at break)
The sample for elongation test was punched with a No. 3 dumbbell. The punched sample was stored for 24 hours in a room adjusted to 23 ° C. and 50% relative humidity. After storage, using a tensile tester, a tensile test according to JIS K6301 was performed, the sample was pulled at 300 mm / min, and the elongation at break was recorded. The results are shown in Table 4 below.

(Measurement of water contact angle)
About the sample for a contamination | contamination property and a water contact angle test, the water contact angle was measured with the contact angle meter by KRUS. The results are shown in Table 4 below.

(Contamination evaluation)
On the rooftop of a building in Osaka Prefecture, make a glass plate on which the sample for contamination and water contact angle test is formed on the glass plate so that the surface forms an angle of 60 ° with respect to the ground horizontal to gravity. Placed southward and exposed outdoors for 12 months. The brightness before and after exposure was measured with a color difference meter (manufactured by Nippon Denshoku Industries Co., Ltd.). When the average brightness before exposure was X and the average brightness Y after exposure was (XY), the average brightness difference was taken as an index of contamination. A smaller average brightness difference means lower contamination. The results are shown in Table 4 below.

(Evaluation of visual appearance (dirt))
The dirt after the contamination test was observed and evaluated visually. The results are indicated by the following evaluation symbols.

  A: Rain lines and dirt are not seen from 1 m in front of the glass plate, but rain lines and dirt are seen from 0.5 m in front of the glass plate.

  ○: Rain stripes and dirt are not seen from 5 m ahead of the glass plate, but rain stripes and dirt are seen from 1 m ahead of the glass plate.

  Δ: Rain stripes and dirt are not seen from 10 m ahead of the glass plate, but rain stripes and dirt are seen from 5 m ahead of the glass plate.

  X: Rain lines and dirt can be seen from the front 10 m of the glass plate.

(Visual (appearance crack) evaluation)
Moreover, in the said contamination | contamination evaluation, it observed from 0.2 m ahead of the glass plate by visual observation, and observed whether the sample had a crack. When a crack is not recognized, a circle mark is given. When a crack is recognized, a cross mark is given, and the results are shown in Table 4 below.

  The contents of the names of compounds in Tables 1, 3 and 4 are as shown in Table 2 below.

As is clear from Table 4, in Comparative Example 1, the elongation at break was sufficient, but the water contact angle was as large as 92 °, and therefore, considerable contamination was observed in the contamination evaluation. In the visual appearance evaluation, a considerable amount of dirt was recognized. On the other hand, in Comparative Example 2, since the water contact angle was as small as 52 °, the contamination evaluation was excellent. However, the elongation at break was as small as 2%, and cracks were observed in the visual appearance (cracking) evaluation. It was. In Comparative Example 3, although the elongation at break was relatively high at 450% and the flexibility was excellent, the water contact angle stayed at 89 °. Therefore, the stain was considerably recognized in the stain evaluation, and the visual appearance (dirt) was evaluated. In, considerable contamination was observed. On the other hand, in Examples 1 to 5, the elongation at break is sufficient as 15% or more, excellent in flexibility, no crack is observed in the visual appearance (crack) evaluation, and the water contact angle is 72 °. Therefore, good results were obtained in the evaluation of contamination and visual appearance (dirt).

Claims (5)

  An acrylic polymer having at least one polar functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an amino group and a sulfone group, and a hydrolyzable reactive silicon group, and the main chain being an acrylate polymer A curable composition comprising 100 parts by weight and 1 to 5 parts by weight of a curing catalyst for moisture-curing the acrylic polymer.   The curable composition according to claim 1, wherein the polar functional group is a hydroxyl group.   The hardening of Claim 1 or 2 whose contact angle with the water of the hardened | cured material of the said curable composition is 70 degrees or less, and the elongation at the time of the cutting | disconnection in the tension test based on JISK6301 is 10% or more. Sex composition.   The curable composition of any one of Claims 1-3 which is a sealing material. The curable composition according to any one of claims 1 to 3, which is an elastic adhesive.