JP6350963B2 - Sealing method - Google Patents

Description

The present invention relates to an organic polymer having a silicon-containing group having a hydroxyl group or a hydrolyzable group bonded to a silicon atom and capable of crosslinking by forming a siloxane bond, and a compound having two or more epoxy groups in the molecule. The present invention relates to a method for sealing a siding board using the curable composition as a sealing material.
Hereinafter, a silicon-containing group having a hydroxyl group or a hydrolyzable group bonded to a silicon atom and capable of crosslinking by forming a siloxane bond is also referred to as a crosslinkable silicon group. A compound having two or more epoxy groups in the molecule is also referred to as an epoxy resin.

  A siding board is a board made of various materials used for an outer wall of a low-rise building such as a detached house. When the siding board is attached to the building, a gap (joint) is generated between the siding board and other members of the building or between the siding board and the other siding board. If the gap is left as it is, water and wind will enter when exposed to wind and rain, so the gap is filled with a sealing material to provide water tightness (waterproof) and air tightness (blocking from outside air). Is done.

  As described in Patent Documents 1 and 2, as a sealing material, it is liquid before curing and can be easily filled into joints. After filling, it can be left alone or cured at room temperature with moisture in the air. Thus, a curable composition containing an organic polymer having a crosslinkable silicon group that forms a rubber-like product is often used.

  In general, since the width of joints varies depending on temperature changes, building movements, etc., the sealing material is required not to crack or peel even if the joint width varies. This often requires a sealant having excellent adhesion to the substrate, high elongation at break, and low tensile modulus.

Such a characteristic is particularly necessary for a sealing material for ceramic siding boards that undergoes significant shrinkage over time. Ceramic siding boards are building materials used for wall materials that are hardened by blending organic fibers with main raw materials such as cement, fly ash, and pearlite, and are inexpensive and fire-resistant materials. According to Non-Patent Document 1, the sealing material for ceramic siding boards has a low 50% tensile modulus of 0.05 to 0.4 N / mm ² not only after curing of the sealing material but also after water resistance test and heat resistance test. , A breaking strength of 0.2 N / mm ² or more and a breaking elongation of 250% or more are desirable.

  Regarding the adhesiveness to the base material, the state at the time of breaking is preferably cohesive failure of the sealing material itself, and peeling at the interface with the base material and destruction of the siding board itself are not preferable. Not limited to ceramic siding boards, sealing materials generally require excellent adhesion to substrates, high elongation at break and low modulus.

  A cured product of the curable composition containing an organic polymer having a crosslinkable silicon group is excellent in tensile modulus, breaking strength, breaking elongation or adhesion to a substrate. Moreover, in order to improve adhesiveness, it is also common to add an adhesive imparting agent. However, as described in Patent Document 3 (paragraph 0002), the cured product of such a curable composition is known to have a problem that the adhesiveness is lowered after the water resistance test, which improves the water resistant adhesiveness. Therefore, a curable composition using an epoxy resin has been proposed. In fact, in Examples of Patent Documents 3 to 5, the curable composition containing an organic polymer having a crosslinkable silicon group and an epoxy resin is improved in water-resistant adhesion as compared with the curable composition not containing an epoxy resin. Has been shown to be.

  However, although the curable composition containing an organic polymer having a crosslinkable silicon group and an epoxy resin improves the water-resistant adhesion of the cured product, the elongation at break may be insufficient after the water resistance test. It has been found that the composition may not be desirable for use as a sealing material for siding boards. It has also been found that the curable composition containing an organic polymer having a crosslinkable silicon group and an epoxy resin may have insufficient elongation at break even after the heat resistance test of the cured product.

JP 2001-271055 A JP 2004-107608 A JP 2007-269988 A JP-A-11-349663 JP 2000-017051 A

“NPO Corporation Housing Exterior Technical Center Standard JTC S-0001 Sealing Material for Ceramic Siding” 2004 (http://www.jtc.or.jp/seinou/kikaku_data/S-0001(seal).pdf)

  The problem to be solved by the present invention is a method for sealing a siding board using a curable composition containing an organic polymer having a crosslinkable silicon group, an epoxy resin and an adhesion-imparting agent as a sealing material, It is to provide a sealing method in which the elongation at break of the material is improved. In particular, it is to provide a sealing method in which the elongation at break of a sealing material is improved after a water resistance test or a heat resistance test.

  The above problem is solved by the following sealing method.

(1) A sealing method for ceramic siding boards, which has (A) a hydroxyl group or hydrolyzable group bonded to a silicon atom as a sealing material, and a silicon-containing group that can be crosslinked by forming a siloxane bond. 100 parts by mass of an organic polymer, (B) 1 to 100 parts by mass of a compound having two or more epoxy groups in the molecule, (C) a hydroxyl group having one epoxy group in the molecule and bonded to a silicon atom or 1 to 100 parts by mass of a compound having a hydrolyzable group and not having a silicon-containing group that can be crosslinked by forming a siloxane bond, and (D) an adhesion-imparting agent ( having two or more epoxy groups in the molecule) A method for sealing a ceramic siding board characterized by using a curable composition containing 0.1 to 20 parts by mass.

(2) Sealing method ceramic siding boards according to characterized by applying a sealing material (1) without applying a primer to the sealing portion of the ceramic siding board.

  According to the sealing method of the present invention, the cured product of the sealing material has a large elongation property at break, and this elongation property is excellent even after water immersion or heat exposure, so that the watertightness and airtightness of the siding board are improved. It will be certain.

  In the sealing material used in the method of the present invention, the crosslinkable silicon group in the organic polymer of the component (A) has a hydroxyl group or a hydrolyzable group bonded to a silicon atom and can be crosslinked by forming a siloxane bond. It is. As a representative example, the formula (1):

(In the formula, R ¹ represents an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, or R ¹ ₃ SiO— (R ¹ is the same as above), and when two or more R ¹ are present, they may be the same or different, and X is a hydroxyl group or a hydrolyzable group. Represents a group, and when two or more X are present, they may be the same or different, a represents 0, 1, 2 or 3, b represents 0, 1 or 2; And n formulas (2):

B in need not be the same. n shows the integer of 0-19. However, a + (sum of b) ≧ 1 is satisfied. ).
The hydrolyzable group or hydroxyl group can be bonded to one silicon atom in the range of 1 to 3, and a + (sum of b) is preferably in the range of 1 to 5. When two or more hydrolyzable groups or hydroxyl groups are bonded to the crosslinkable silicon group, they may be the same or different.

The number of silicon atoms forming the crosslinkable silicon group may be one or two or more, but in the case of silicon atoms linked by a siloxane bond or the like, there may be about 20 silicon atoms.
Formula (3):

A crosslinkable silicon group represented by the formula (wherein R ¹ , X and a are the same as described above) is preferable from the viewpoint of easy availability. In the crosslinkable silicon group of the formula (3), a is preferably 2 or 3. When a is 3, the curing rate is higher than when a is 2.

Specific examples of R ¹ include an alkyl group such as a methyl group and an ethyl group, a cycloalkyl group such as a cyclohexyl group, an aryl group such as a phenyl group, an aralkyl group such as a benzyl group, and R ¹ ₃ SiO—. And triorganosiloxy group. Of these, a methyl group is preferred.

  It does not specifically limit as a hydrolysable group shown by said X, What is necessary is just a conventionally well-known hydrolysable group. Specific examples include a hydrogen atom, a halogen atom, an alkoxy group, an acyloxy group, a ketoximate group, an amino group, an amide group, an acid amide group, an aminooxy group, a mercapto group, and an alkenyloxy group. Among these, a hydrogen atom, an alkoxy group, an acyloxy group, a ketoximate group, an amino group, an amide group, an aminooxy group, a mercapto group, and an alkenyloxy group are preferable, and an alkoxy group, an amide group, and an aminooxy group are more preferable. An alkoxy group is particularly preferred from the viewpoint of mild hydrolysis and easy handling. Among the alkoxy groups, those having a smaller number of carbon atoms have higher reactivity, and the reactivity increases as the number of carbon atoms increases in the order of methoxy group> ethoxy group> propoxy group. Although it can be selected according to the purpose and application, a methoxy group or an ethoxy group is usually used. In the case of the crosslinkable silicon group represented by the formula (3), a is preferably 2 or more in consideration of curability.

Specific examples of the crosslinkable silicon group include trialkoxysilyl groups such as a trimethoxysilyl group and a triethoxysilyl group, dialkoxysilyl groups such as —Si (OR) ₃ , a methyldimethoxysilyl group, and a methyldiethoxysilyl group. Group, —SiR ¹ (OR) ₂ . Here, R ¹ is the same as described above, and R is an alkyl group such as a methyl group or an ethyl group.

  Further, the crosslinkable silicon group may be used alone or in combination of two or more. The crosslinkable silicon group can be present in the main chain, the side chain, or both. It is preferable that a crosslinkable silicon group is present at the end of the molecular chain from the viewpoint of excellent cured product properties such as tensile properties of the cured product.

  It is preferable that at least one, preferably 1.1 to 5, crosslinkable silicon groups are present in one molecule of the polymer. When the number of crosslinkable silicon groups contained in the molecule is less than one, the curability is insufficient, and when the number is too large, the network structure becomes too dense, and good mechanical properties are not exhibited. In particular, in the case of producing a so-called non-plastic compounding curable composition that does not contain a low molecular weight plasticizer having a molecular weight of 800 or less, such as a phthalate ester plasticizer, and a molecular weight of 1000 or less, a crosslinkable silicon group is used. Are present in an average of 1.1 to 1.5, more preferably 1.1 to 1.3 per molecule of polymer. In the case of a curable composition containing no plastic, it is preferable to use a linear polymer.

  The main chain skeleton of the organic polymer having a crosslinkable silicon group is not particularly limited, and those having various main chain skeletons can be used. Specifically, polyoxyalkylene heavy polymers such as polyoxyethylene, polyoxypropylene, polyoxybutylene, polyoxytetramethylene, polyoxyethylene-polyoxypropylene copolymer, polyoxypropylene-polyoxybutylene copolymer, etc. Copolymer; ethylene-propylene copolymer, polyisobutylene, copolymer of isobutylene and isoprene, polychloroprene, polyisoprene, isoprene or copolymer of butadiene and acrylonitrile and / or styrene, polybutadiene, isoprene or butadiene Copolymers of acrylonitrile and / or styrene, etc., and hydrocarbon polymers such as hydrogenated polyolefin polymers obtained by hydrogenating these polyolefin polymers; adipic acid, terephthalic acid Polyester polymers such as condensation polymers of polybasic acids such as succinic acid and polyhydric alcohols such as bisphenol A, ethylene glycol and neopentyl glycol, and ring-opening polymers of lactones; by ring-opening polymerization of ε-caprolactam Nylon 6, Nylon 6 · 6 by condensation polymerization of hexamethylenediamine and adipic acid, Nylon 6 · 10 by condensation polymerization of hexamethylenediamine and sebacic acid, Nylon 11 by condensation polymerization of ε-aminoundecanoic acid, ε-aminolaurolactam Nylon 12 by ring-opening polymerization of the above, polyamide-based polymer such as copolymer nylon having two or more components among the above nylons; polyacrylic obtained by ion polymerization or radical polymerization of monomers such as ethyl acrylate and butyl acrylate Acid ester, ethyl acrylate, butyl acetate An acrylic acid ester-based polymer such as an acrylic acid ester copolymer of an acrylic acid ester such as a rate and vinyl acetate, acrylonitrile, methyl methacrylate, styrene, etc .; obtained by polymerizing a vinyl monomer in the organic polymer Examples include graft polymers; polysulfide polymers; polycarbonate polymers produced by condensation polymerization from bisphenol A and carbonyl chloride, diallyl phthalate polymers, and the like.

  Of the polymers having the main chain skeleton, polyester polymers, acrylate polymers, polyoxyalkylene polymers, hydrocarbon polymers, polycarbonate polymers and the like are preferable. In particular, it is easy to introduce a crosslinkable silicon group into the molecular chain end, is relatively low in viscosity and inexpensive, has a low glass transition temperature, and the resulting cured product has excellent cold resistance, heat resistance and weather resistance. Acrylic acid alkyl ester polymers that are excellent in properties and adhesiveness are preferred.

  Furthermore, since the mixture of the polyoxyalkylene polymer and the (meth) acrylic acid alkyl ester polymer is excellent in the mechanical strength of the cured product, and has excellent properties in heat resistance and adhesion to the substrate, It is particularly suitable for the present invention. When a mixture of an oxyalkylene polymer having a crosslinkable silicon group and a (meth) acrylic acid ester polymer having a crosslinkable silicon group is used, (meth) acrylic acid is used with respect to 100 parts by weight of the oxyalkylene polymer. The ester polymer is preferably used in an amount of 5 to 200 parts by weight, more preferably 5 to 50 parts by weight.

  The organic polymer having a crosslinkable silicon group may be linear or branched, and preferably has a number average molecular weight of about 500 to 50,000, more preferably 1,000 to 30,000. As the molecular weight increases, the hardness tends to decrease.

  Among the above polymers, the polyoxyalkylene polymer is essentially a polymer having a repeating unit represented by the formula (4).

(Wherein R ² is a divalent organic group)
R ² in Formula (4) is preferably a linear or branched alkylene group having 1 to 14 carbon atoms, and more preferably 2 to 4 carbon atoms. Specific examples of the repeating unit represented by the formula (4) include, for example,

Etc. The main chain skeleton of the polyoxyalkylene polymer may be composed of only one type of repeating unit, or may be composed of two or more types of repeating units. In particular, it is preferably made of a polymer mainly composed of oxypropylene.

  When a polyoxyalkylene polymer is used, its molecular weight is preferably larger because the tensile modulus, which is the tensile property of the cured product, is reduced and the elongation at break is increased. In the present invention, the lower limit of the number average molecular weight is preferably 15,000, more preferably 20,000, and particularly preferably 25,000. Further, the upper limit of the number average molecular weight is preferably 50,000, and more preferably 40,000. In addition, the number average molecular weight as used in the field of this invention means the polystyrene conversion molecular weight by gel permeation chromatography. When the number average molecular weight is less than 20,000, the tensile modulus or elongation at break may not be sufficient. When the number average molecular weight exceeds 50,000, the viscosity of the composition may increase and workability may decrease.

  The polyoxyalkylene polymer may be linear or branched, but is preferably a linear polymer because the tensile modulus can be reduced and the elongation at break can be increased. The molecular weight distribution of the polyoxyalkylene polymer having a crosslinkable silicon group is preferably 2 or less, particularly 1.6 or less.

  As a method for synthesizing a polyoxyalkylene polymer, for example, a polymerization method using an alkali catalyst such as KOH, for example, JP-A Nos. 61-197631, 61-215622, 61-215623, and 61-215623 can be used. Polymerization methods using an organoaluminum-porphyrin complex catalyst obtained by reacting an organoaluminum compound with porphyrin as shown, for example, double metal cyanide complexes shown in JP-B-46-27250 and JP-B-59-15336 Examples of the polymerization method using a catalyst include, but are not limited to, a polymerization method. According to the polymerization method using an organoaluminum-porphyrin complex catalyst or the polymerization method using a double metal cyanide complex catalyst, the number average molecular weight is 6,000 or more, and the Mw / Mn is 1.6 or less. Coalescence can be obtained.

  The main chain skeleton of the polyoxyalkylenes may contain other components such as a urethane bond component. Examples of the urethane bond component include aromatic polyisocyanates such as toluene (tolylene) diisocyanate, diphenylmethane diisocyanate and xylylene diisocyanate; aliphatic polyisocyanates such as isophorone diisocyanate and hexamethylene diisocyanate and polyoxyalkylenes having a hydroxyl group; What can be obtained from this reaction can be mentioned.

  The introduction of a crosslinkable silicon group into a polyoxyalkylene polymer can be performed on a polyoxyalkylene polymer having a functional group such as an unsaturated group, a hydroxyl group, an epoxy group or an isocyanate group in the molecule. The reaction can be carried out by reacting a compound having a reactive functional group and a crosslinkable silicon group. This method (hereinafter referred to as polymer reaction method) is also suitably used for polyester polymers, polyamide polymers, and polymers of unsaturated monomers obtained by living polymerization. This is because these polymers have a functional group such as a hydroxyl group at the molecular chain terminal, so that a crosslinkable silicon group can be easily introduced into the terminal.

  As a specific example of the polymer reaction method, a hydrosilane or mercapto compound is produced by reacting an unsaturated group-containing oxyalkylene polymer with a hydrosilane having a crosslinkable silicon group or a mercapto compound having a crosslinkable silicon group to form a crosslinkable silicon group. The method of obtaining the oxyalkylene type polymer which has can be mention | raise | lifted. An unsaturated group-containing oxyalkylene polymer is an organic compound having an active group and an unsaturated group that are reactive with an organic polymer having a functional group such as a hydroxyl group, such as an unsaturated halogen compound. To give an oxyalkylene polymer containing an unsaturated group.

  Other specific examples of the polymer reaction method include a method of reacting an oxyalkylene polymer having a hydroxyl group at a terminal with a compound having an isocyanate group and a crosslinkable silicon group, or an oxyalkylene polymer having an isocyanate group at a terminal. And a method of reacting a compound having an active hydrogen group such as a hydroxyl group or an amino group and a crosslinkable silicon group. When an isocyanate compound is used, an oxyalkylene polymer having a crosslinkable silicon group can be easily obtained. The polymer reaction method can be applied to polymers other than oxyalkylene polymers.

  Specific examples of the oxyalkylene polymer having a crosslinkable silicon group include JP-B Nos. 45-36319 and 46-12154, JP-A Nos. 50-156599, 54-6096, and 55-13767. No. 57-164123, Japanese Patent Publication No. 3-2450, Japanese Patent Application Laid-Open No. 2005-213446, No. 2005-306891, International Publication No. WO 2007-040143, US Pat. Nos. 3,632,557, 4,345,053, The ones proposed in the publications such as 4,960,844 can be mentioned.

  The (meth) acrylic acid alkyl ester polymer having a crosslinkable silicon group is essentially a polymer having a repeating unit represented by the formula (5).

(Wherein R ³ represents a hydrogen atom or a methyl group, and R ⁴ represents an alkyl group)
R ⁴ in Formula (5) is an alkyl group, and an alkyl group having 1 to 30 carbon atoms is preferable. R ⁴ may be linear or branched. Moreover, the substituted alkyl group which has a halogen atom, a phenyl group, etc. may be sufficient. Examples of R ⁴ include methyl group, ethyl group, propyl group, n-butyl group, t-butyl group, 2-ethylhexyl group, lauryl group, tridecyl group, cetyl group, stearyl group, and behenyl group. it can.

  The molecular chain of the (meth) acrylic acid alkyl ester polymer consists essentially of the monomer unit of the formula (5), and the term “essentially” as used herein means that of the formula (5) present in the polymer. It means that the total of monomer units exceeds 50% by weight. The total of the monomer units of the formula (5) is preferably 70% by weight or more.

  Examples of monomer units other than formula (5) include (meth) acrylic acid such as acrylic acid and methacrylic acid; amide groups such as acrylamide, methacrylamide, N-methylolacrylamide, and N-methylolmethacrylamide, glycidyl acrylate Monomers containing amino groups such as epoxy groups such as glycidyl methacrylate, diethylaminoethyl acrylate, diethylaminoethyl methacrylate, aminoethyl vinyl ether; other acrylonitrile, styrene, α-methylstyrene, alkyl vinyl ether, vinyl chloride, vinyl acetate, propionic acid Examples thereof include monomer units derived from vinyl, ethylene and the like.

  As described above, the (meth) acrylic acid alkyl ester polymer having a crosslinkable silicon group may be used in combination with an oxyalkylene polymer. In this case, in terms of high compatibility with the oxyalkylene polymer having a crosslinkable silicon group, the molecular chain having a crosslinkable silicon group has the following formula (6):

(Wherein R ³ is the same as above, R ⁵ represents an alkyl group having 1 to ⁵ carbon atoms) and a (meth) acrylate monomer unit represented by the following formula (7):

(Wherein R ³ is the same as described above, and R ⁶ represents an alkyl group having 6 or more carbon atoms). A copolymer comprising a (meth) acrylic acid ester monomer unit is preferred.
As R < ⁵ > of said Formula (6), C1-C5, such as a methyl group, an ethyl group, a propyl group, n-butyl group, t-butyl group, etc., Preferably it is 1-4, More preferably, it is 1-2. Of the alkyl group. Incidentally, R ⁵ may be a kind, or may be a mixture of two or more.
R ^{6 in the} formula (7) is, for example, 2-ethylhexyl group, lauryl group, tridecyl group, cetyl group, stearyl group, behenyl group and the like having 6 or more carbon atoms, usually 7-30, preferably 8-20. Long chain alkyl groups. R ⁶ may be a single type or a mixture of two or more types. Moreover, the weight ratio of the monomer unit of the formula (6) and the monomer unit of the formula (7) is preferably 95: 5 to 40:60, and more preferably 90:10 to 60:40.

  The (meth) acrylic acid alkyl ester polymer having a crosslinkable silicon group can usually be obtained by radical copolymerization of a (meth) acrylic acid alkyl ester and a (meth) acrylic acid alkyl ester having a crosslinkable silicon group. . Further, when an initiator having a crosslinkable silicon group or a chain transfer agent having a crosslinkable silicon group is used, the crosslinkable silicon group can be introduced into the molecular chain terminal.

  JP 2001-040037 A, JP 2003-048923 A and JP 2003-048924 A have a crosslinkable silicon group (meth) obtained by using a mercaptan having a crosslinkable silicon group and a metallocene compound. Acrylic acid alkyl ester polymers are described. Moreover, the synthesis example of Unexamined-Japanese-Patent No. 2005-026881 describes the (meth) acrylic-acid alkylester type polymer which has a crosslinkable silicon group by high temperature continuous polymerization.

  As disclosed in JP-A-2000-086999, a (meth) acrylic acid alkyl ester-based polymer having a crosslinkable silicon group, in which a crosslinkable silicon group is introduced at a high ratio at the molecular chain terminal, Are known. Since such a polymer is produced by living radical polymerization, a crosslinkable silicon group can be introduced into the molecular chain terminal at a high rate. In the present invention, a (meth) acrylic acid alkyl ester polymer as described above can be used.

  Specific examples of a (meth) acrylic acid ester-based polymer having a crosslinkable silicon group and a mixture of this polymer and an oxyalkylene polymer having a crosslinkable silicon group are disclosed in JP-A Nos. 59-122541 and 63-112642. And in each publication such as JP-A-6-172631. JP-A-59-78223, JP-A-59-168014, JP-A-60-228516, JP-A-60-228517, etc. disclose oxyalkylene polymers having a crosslinkable silicon group. (Meth) acrylic acid ester-based monomer is polymerized in the presence of a mixture of an oxyalkylene polymer having a crosslinkable silicon group and a (meth) acrylic acid alkyl ester polymer having a crosslinkable silicon group. The method of obtaining is described.

Examples of the compound having two or more epoxy groups in the molecule as the component (B) used in the present invention include epichlorohydrin-bisphenol A type epoxy resin, epichlorohydrin-bisphenol F type epoxy resin, glycidyl ether of tetrabromobisphenol A, etc. Flame retardant type epoxy resin, novolak type epoxy resin, hydrogenated bisphenol A type epoxy resin, glycidyl ether type epoxy resin of bisphenol A propylene oxide adduct, p-oxybenzoic acid glycidyl ether ester type epoxy resin, m-aminophenol type epoxy resin Resin, diaminodiphenylmethane epoxy resin, urethane-modified epoxy resin, various alicyclic epoxy resins, N, N-diglycidylaniline, N, N-diglycidyl-o-toluidine, triglycidyl Examples include, but are not limited to, glycidyl ethers of polyhydric alcohols such as sosocyanurates, polyalkylene glycol diglycidyl ethers, glycerins, and the like, epoxidized products of unsaturated polymers such as hydantoin type epoxy resins, petroleum resins, etc. Rather, commonly used epoxy resins can be used.
Of these epoxy resins, the following formula (8)

A compound containing at least two epoxy groups represented by the formula is preferable from the viewpoints of high reactivity during curing and that the cured product easily forms a three-dimensional network. More preferred are bisphenol A type epoxy resins or bisphenol F type epoxy resins, bisphenol AD type epoxy resins, novolac type epoxy resins and the like. Most preferred are bisphenol A type epoxy resins. A compound having two or more epoxy groups in the molecule has a function of improving the adhesiveness of the oxyalkylene polymer having a crosslinkable silicon group. The epoxy resin is preferably liquid at normal temperature. Moreover, it is preferable that the molecular weight of an epoxy resin is 500 or less.

  (B) The usage-amount of an epoxy resin is the range of 1-100 mass parts with respect to 100 mass parts of (A) organic polymer which has a crosslinkable silicon group. If it is less than 1 part by mass, the adhesiveness of the cured product of the composition will be insufficient, and if it exceeds 100 parts by mass, the flexibility of the cured product of the composition will be insufficient. A preferable range is 2 to 50 parts by mass, further 5 to 30 parts by mass, particularly 5 to 20 parts by mass.

  As the compound (C) used in the present invention, a compound having one epoxy group in the molecule and not having a crosslinkable silicon group (hereinafter also referred to as monofunctional epoxy compound) includes butyl glycidyl ether, 2-ethylhexyl. Glycidyl ether, alkyl monoglycidyl ether, phenyl glycidyl ether, cresyl glycidyl ether, allyl glycidyl ether, pt-butylphenyl glycidyl ether, nonylphenyl glycidyl ether, p-sec-butylphenyl glycidyl ether, alkylphenol monoglycidyl ether, versa Glycidides such as tick acid monoglycidyl ester, linear alcohol monoglycidyl ether, glycerol monoglycidyl ether, polyglycol glycidyl ether, glycidyl methacrylate Ether, glycidyl ester or a mixture thereof, 1,2-epoxydodecane, 1,2-epoxydosane, epoxy hydrocarbon such as styrene oxide or a mixture thereof, epoxidized soybean oil, epoxidized linseed oil, epoxy benzyl stearate, etc. Epoxy plasticizers or mixtures thereof, cyclohexane oxide, 4-vinyl epoxycyclohexane, 3,4-epoxycyclohexyl methanol, 3,4-epoxycyclohexylmethyl methacrylate, di-2-ethylhexyl epoxyhexahydrophthalate,

Examples thereof include, but are not limited to, alicyclic epoxy compounds.
Of these, alicyclic epoxy compounds are preferred, and cyclohexane epoxide derivatives are more preferred.

  (C) The usage-amount of a monofunctional epoxy compound is the range of 1-100 mass parts with respect to 100 mass parts of (A) organic polymer which has a crosslinkable silicon group. Preferably, it is the said range, and is a range of 10-500 mass parts with respect to 100 mass parts of epoxy resins, and also the range of 50-200 mass parts for a monofunctional epoxy compound.

  When a compound having two or more epoxy groups in the molecule of the component (B) is added to the organic polymer having a crosslinkable silicon group of the component (A), the adhesion of the cured product of the component (A) to the substrate Although the strength is improved, the flexibility is lowered, and the elongation property is inferior particularly after being immersed in water or exposed to heat. Therefore, such a curable composition may be difficult to use for a sealing material that is flexible and requires elongation characteristics.

Here, the addition of a compound having one epoxy group in the molecule of component (C) together with component (B) and not having a crosslinkable silicon group can improve the flexibility of the cured product and is immersed in water. It is possible to prevent the elongation characteristics from being lowered later or after heat exposure. The cured product of the curable composition used in the present invention conforms to “NPO Corporation Housing Exterior Technical Center Standard JTC S-0001 Ceramic Sealing Material for Siding” 2004 (hereinafter also referred to as “Siding Sealing Material Standard”). Thus, the initial 50% tensile stress at a test temperature of 23 ° C. measured can be less than 0.4 N / mm ² . The component (C) must have no crosslinkable silicon group. In the case of having a crosslinkable silicon group, the crosslinkable silicon group causes a crosslinking reaction with the polymer of the component (A), so that the flexibility cannot be improved, and it is also possible to prevent the elongation characteristics from being deteriorated after being immersed in water or exposed to heat. Can not.

  The adhesiveness imparting agent which is the component (D) used in the present invention is for improving the adhesion to the substrate. Examples of the adhesion-imparting agent include a silane coupling agent, a titanium coupling agent, and an aluminum coupling agent, and a silane coupling agent is preferable. A silane coupling agent is a compound having a crosslinkable silicon group and another functional group.

  Examples of such silane compounds include vinylalkyl (1 to 4 carbon atoms) alkoxy (1 to 4 carbon atoms) silane (for example, vinyltrimethoxysilane, vinyltriethoxysilane, etc.), (meth) acryloyloxyalkyl (carbon number). 1-4) alkoxy (C1-C4) silane (e.g., [gamma] -methacryloxypropyltrimethoxysilane), alkyl (C1-C4) alkoxy (C1-C4) silane (e.g., methyltrimethoxysilane), Methyltriethoxysilane and the like), amino (1 to 4 in the molecule) alkyl (2 to 15 carbon atoms) alkoxy (1 to 4 carbon atoms) silane (for example, γ- (2-aminoethyl) aminopropyltrimethoxysilane, Aminopropyltrimethoxysilane, N-phenylaminopropylmethyldimethoxysilane, etc.), epoxy (molecule 1 to 4) alkyl (1 to 4 carbon atoms) alkoxy (1 to 4 carbon atoms) silane (for example, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane), mercapto ( Examples thereof include 1 to 4 in the molecule, alkyl (1 to 4 carbon atoms), alkoxy (1 to 4 carbon atoms) silane (for example, γ-mercaptopropyltrimethoxysilane) and the like.

  Among these, a silane coupling agent having an amino group and a crosslinkable silicon group (hereinafter also referred to as aminosilane) is preferable because it has a large effect of improving adhesiveness. Aminosilane also acts as an epoxy resin curing accelerator. Further, when an alkoxysilane compound that reacts with water to produce an amine compound having at least one alkoxysilyl group in one molecule is used, such as a ketiminosilane having an amino group ketiminated, an epoxy is used during storage of the composition. Since it does not react with the resin, a one-component composition can be obtained. Alkoxysilane compounds which react with water to produce amine compounds having at least one alkoxysilyl group in one molecule are KBE-9103 (manufactured by Shin-Etsu Chemical Co., Ltd.), Silaace S340 (manufactured by Chisso Corporation), Z -6860 (manufactured by Toray Dow Corning Co., Ltd.) and the like.

  The amount of the component (D) adhesion-imparting agent used is 0.1 to 20 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the organic polymer having a crosslinkable silicon group (A). is there. These adhesiveness-imparting agents can be used in combination of two or more.

  An epoxy resin curing agent, plasticizer, filler, anti-aging agent, silanol condensation catalyst, ultraviolet absorber, lubricant, pigment, foaming agent and the like are further added to the curable composition used in the present invention as necessary. be able to.

  As the epoxy resin curing agent, one or a plurality of commercially available epoxy resin curing agents can be selected and used. Examples of such a curing agent include amines, acid anhydrides, imidazoles, and other curing agents.

  As amines, primary to tertiary amines can be used. Primary amines include aliphatic amines (diethylenetriamine, triethylenetetramine, tetraethylenepentamine, dipropylenetriamine, polymethylenediamine (trimethylhexamethylenediamine, polyetherdiamine, diethylaminopropylamine)), alicyclic amines (men Sendiamine), aliphatic amines containing aromatic rings (metaxylenediamine), aromatic amines (metaphenylenediamine, diaminodiphenylmethane, diaminodiphenylsulfone, aromatic diamine eutectic mixture), 3,9-bis (3-aminopropyl) ) -2,4,8,10-tetraspiro [5,5] undecane) and modified amines (amine adducts, cyanoethylated polyamines). Examples of secondary and tertiary amines include linear secondary amines, linear tertiary amines, tetramethylguanidine, piperidine, pyridine, picoline, benzyldimethylamine, and 2- (dimethylaminomethyl) phenol.

  Acid anhydrides include aromatic anhydrides (phthalic anhydride, trimellitic anhydride, ethylene glycol bis (anhydrotrimellitate), glycerol tris (anhydrotrimellitate), pyromellitic anhydride, 3, 3 ', 4,4'-benzophenonetetracarboxylic anhydride), cycloaliphatic anhydride (maleic anhydride, succinic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, alkenyl anhydride Acid, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylcyclohexene tetracarboxylic acid anhydride), aliphatic acid anhydride, polycarboxylic acid anhydride, halogenated acid anhydride, and chloresidic acid anhydride.

  Examples of imidazoles include 2-methylimidazole, 2-ethyl-4methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-phenylimidazole, 1-benzyl-2-methylimidazole, 1-cyanoethyl-2- Methylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 2,4-diamino-6- [2-methylimidazolyl- (1)]-ethyl-S-triazine, quaternary salt (1-dodecyl-2 -Methyl-3-benzylimidazolium chloride), isocyanurate (2-phenylimidazolium isocyanurate), hydroxymethyl (2-phenyl-4-methyl-5-hydroxymethylimidazole), boron trifluoride-amine A complex can be exemplified.

  Other curing agents include polyamide resin (condensate of dimer acid and polyamine), dicyandiamide and its derivatives, (o-tolylbiguanide, α-2,5-dimethylbiguanide), organic acid hydrazide (succinic acid hydrazide, adipic acid) Hydrazide), derivatives with diaminomaleonitrile, melamine and its derivatives, amine imides, polyamine salts, oligomers: synthetic resin initial condensate (novolac phenol resin, novolac cresol resin), polyvinylphenol (poly-p-vinylphenol) Can be mentioned.

  In particular, it is preferable to use amines, and a resin composition having excellent curability can be obtained. In addition, a compound in which an amino group is ketiminated can be used. In this case, a one-component curable composition that does not cure during storage can be easily produced.

  When using an epoxy resin hardening | curing agent, 5-200 mass parts is used with respect to 100 mass parts of epoxy resins. If the curing agent is less than 5 parts by mass, curing is insufficient, and if it is more than 200 parts by mass, the curing agent becomes excessive and the performance after curing is poor.

  Specific examples of the plasticizer include phthalic acid esters such as dioctyl phthalate, dibutyl phthalate and butyl benzyl phthalate; aliphatic dibasic acid esters such as dioctyl adipate, isodecyl succinate and dibutyl sebacate; diethylene glycol dibenzoate, penta Glycol esters such as erythritol ester; aliphatic esters such as butyl oleate and methyl acetylricinoleate; phosphate esters such as tricresyl phosphate, trioctyl phosphate and octyl diphenyl phosphate; dibasic acid and dihydric alcohol Polyester plasticizers such as polyesters; Polyethers such as polypropylene glycol and its derivatives; Hydrocarbon plastics such as paraffinic hydrocarbons, naphthenic hydrocarbons, and paraffin-naphthene mixed hydrocarbons S; chlorinated paraffins; low molecular weight acrylic ester polymer and the like. These plasticizers may be used alone or in combination of two or more. In particular, when an acrylic ester polymer is used, the weather resistance of the cured product can be improved.

  When using a plasticizer, it is good to use in the range of 10-300 mass parts normally with respect to 100 mass parts of (A) component, Preferably it is the range of 20-250 mass parts. When the amount of the plasticizer used is less than 10 parts by mass, the viscosity of the composition may be too high, and when it exceeds 300 parts by mass, the plasticizer may exude from the cured product. It is not preferable.

  Examples of fillers include reinforcing fillers such as fumed silica, precipitated silica, silicic anhydride and carbon black; calcium carbonate, magnesium carbonate, diatomaceous earth, calcined clay, clay, talc, hardened titanium, bentonite, organic bentonite , Fillers such as ferric oxide, zinc oxide, activated zinc white and shirasu balloon; and fibrous fillers such as asbestos, glass fibers and filaments can be used.

  When it is desired to obtain a cured product having high strength by using these fillers, mainly fumed silica, precipitated silica, anhydrous silicic acid, hydrous silicic acid and carbon black, surface-treated fine calcium carbonate, calcined clay, clay, Preferred results are obtained by using fillers selected from activated zinc white and the like. In addition, when it is desired to obtain a cured product having low strength and large elongation, a filler selected from titanium oxide, calcium carbonate, magnesium carbonate, talc, ferric oxide, zinc oxide, shirasu balloon, etc. is mainly used. Preferred results are obtained when used. Of course, these fillers may be used alone or in combination of two or more.

  When using a filler, it is good to use in the range of 1-300 mass parts normally with respect to 100 mass parts of (A) component, Preferably it is the range of 5-300 mass parts, More preferably, it is 5-250 mass parts. .

  Examples of silanol condensation catalysts include alkyl titanates, organosilicon titanates, bismuth tris 2-ethylhexoate, dibutyltin dilaurate, dibutyltin maleate, dibutyltin diacetate, dioctyltin dilaurate, dioctyltin maleate, dioctyl Mention may be made of metal salts of carboxylic acids such as tin diacetate, tin octylate, tin naphthenate and the like: amine salts such as dibutylamine-2-ethylhexoate, and other acidic and basic catalysts. Of these, organotin compounds are preferred. The silanol condensation catalyst acts as a curing catalyst for the polymer (A) having a crosslinkable silicon group.

When a silanol condensation catalyst is used, it is usually 0.1 to 2 with respect to 100 parts by mass of component (A).
It is good to use in the range of 0 parts by mass, preferably in the range of 0.2 to 10 parts by mass.

  The curable composition used in the present invention may be a one-component curable composition or a multi-component curable composition. In the case of a one-component curable composition, it is easy to use because there is no need for mixing work at the time of use, but components that react with each other like an epoxy resin and an epoxy resin curing agent cannot be used. In addition, the organic polymer having a crosslinkable silicon group as component (A) undergoes a curing reaction in the presence of moisture, so it is necessary to remove the moisture, add a dehydrating agent, and store in a sealed container. In the case of a multi-component curable composition, components that react with each other can be used, but a mixing operation is required at the time of use. The curable composition of the present invention can be suitably used particularly as a one-component type.

  When using the sealing material used in the present invention, a primer can be applied to a substrate, or it can be used without applying a primer. The curable composition of the present invention is excellent in adhesion to a substrate, and has a characteristic of having sufficient adhesion to a substrate without using a primer.

  The sealing material used in the present invention can be suitably used as a sealing material for a siding board that is used outdoors and requires water resistance such as rain water because the modulus of the cured product is small and the elongation is large. In particular, it can be suitably used as a sealing material for ceramic siding boards that has a high moisture content, is porous, and has a small mechanical strength.

  Examples of the siding board include metal siding and ceramic siding in which a metal plate such as an iron plate or an aluminum plate is combined with a heat insulating material.

  Examples of the ceramic siding board include a magnesium carbonate plate, a fiber mixed cement pearlite plate, a fiber mixed slag gypsum plate, an etigrite cement plate, and a pulp mixed calcium silicate plate. These ceramic siding boards generally use as a main raw material a hydraulic inorganic binder such as cement, gypsum, slag and the like, as well as fibers such as asbestos, pulp, glass fiber, and other additives and water. Using this raw material, through raw material mixing, paper making on paper machine (or integral extrusion molding), compression molding, curing (normal pressure wet curing or autoclave curing), drying, finishing, and further, as necessary The product is made by painting a top coat such as acrylic emulsion paint. Ceramic siding boards are subject to greater shrinkage due to moisture evaporation over time.

  The following steps can be exemplified as the steps of the sealing method of the present invention. First, prepare for placing (filling) the sealing material such as cleaning the joints of the siding board attached to the building and joints around the sash, inserting bond breakers and backers, and applying masking tape along the joints. Next, attach the sealant to a gun that is pushed out manually, electrically or pneumatically, fill the prepared joints, scrape off the excess sealant with a spatula, etc. Remove the masking tape. It is left as it is and cured with moisture in the air to make it into a rubber-like material and prevent external water and air from entering. A primer may be applied before filling the joint with the sealing material, but the sealing material of the present invention can also be applied without a primer.

  The present invention will be described more specifically with reference to the following examples. However, it is needless to say that these examples are shown by way of illustration and should not be construed in a limited manner.

(Synthesis Example 1)
Propylene glycol was used as an initiator, and propylene oxide was reacted in the presence of a zinc hexacyanocobaltate-glyme complex catalyst to obtain a hydroxyl-terminated polyoxypropylene having a number average molecular weight of 29,000. To this hydroxyl group-terminated polyoxypropylene polymer, a methanol solution of NaOCH3 was added to distill off the methanol, and allyl chloride was further added to convert the terminal hydroxyl group into an allyl group. After desalting and purification treatment, methyldimethoxysilane, which is a hydrosilyl compound, is reacted in the presence of a platinum catalyst to have a methyldimethoxysilyl group at the end and an average of 1.3 crosslinkable silicon groups in one molecule. A polymer (1) having an average molecular weight of 29,000 was obtained. The number average molecular weight is a polystyrene-equivalent molecular weight measured using Tosoh's HLC-8120GPC as the liquid delivery system, the column using Tosoh's TSK-GELH type, and the solvent using THF.

(Synthesis Example 2)
Propylene glycol was used as an initiator, and propylene oxide was reacted in the presence of a zinc hexacyanocobaltate-glyme complex catalyst to obtain a hydroxyl-terminated polyoxypropylene having a number average molecular weight of 16,000. A methanol solution of NaOCH ₃ was added to the hydroxyl group-terminated polyoxypropylene polymer to distill off the methanol, and allyl chloride was further added to convert the terminal hydroxyl group into an allyl group. After desalting and purification treatment, methyldimethoxysilane, which is a hydrosilyl compound, is reacted in the presence of a platinum catalyst to have a methyldimethoxysilyl group at the terminal and an average of 1.6 crosslinkable silicon groups in one molecule. A polymer (2) having an average molecular weight of 16,000 was obtained.

(Examples 1-3)
As the organic polymer having a crosslinkable silicon group (A) shown in Table 1, the polymer (1) obtained in Synthesis Example 1, the polymer (2) obtained in Synthesis Example 2, and Synthesis Example 3 The obtained polymer (3) and the polymer (4) obtained in Synthesis Example 4 were charged with the three types of polymers, fillers, plasticizers and diluents in the proportions shown in Table 1, and mixed under heating and reduced pressure. Stirring was performed at 110 ° C. for 2 hours to dehydrate the blended material. Furthermore, a predetermined amount of a compound having two or more epoxy groups in the molecule of the component (B), a monofunctional epoxy compound of the component (C), an adhesiveness imparting agent of the component (D) and a curing catalyst is added, and the mixture is stirred. Thus, a sealing material was prepared.
Ceramic siding board (Nichiha wood fiber reinforced cement board, Moen Siding M. Thickness 14mm) is cut into 50mm length and 50mm width so that the two cut siding boards are 10mm apart and the vertical direction is opposite. Fixed to. A foamed polyethylene backup material having a length of 50 mm, a width of 10 mm, and a thickness of 6 mm was placed on the lower surface of the gap, and the surface of the siding board was covered with a masking tape. After filling the sealant with a thickness of 8 mm in the gap (joint) with a space of 10 mm without applying the primer, curing the sealant for 7 days at a temperature of 23 ° C., then removing the masking tape and testing A sample was created.

(Comparative Examples 1-3)
Test samples were prepared in the same manner as in Examples 1 to 3 except that the blending components shown in Table 2 were used.

(Evaluation)
Tensile properties were measured for the samples obtained in Examples 1 to 3 and Comparative Examples 1 to 3, the test sample after immersion in water, and the test sample after heat exposure. The results are shown in Table 1. The conditions for immersion in water and heat exposure, and methods for measuring tensile properties are as follows.

(Water immersion test)
After immersing the test sample in pure water at 23 ° C. for 7 days, the moisture on the surface was wiped off and the tensile properties were measured.

(Thermal exposure test)
The test sample was heated in an oven at 80 ° C. for 14 days, cooled to room temperature, and then measured for tensile properties.

(Tensile property measurement method)
In accordance with the description of the siding sealant standard, the test was conducted in accordance with “5.20 Tensile Adhesion Test” of JIS A1439: 2010 “Testing Method of Architectural Sealant” (test temperature 23 ° C.). After each curing, a tensile adhesion test is performed at a tensile speed of 50 mm / min in an environment of 23 ° C. The load when the elongation is 50%, the maximum load, and the amount of elongation at the maximum load are measured. After the sealing material breaks, visually check the broken state.
The evaluation criteria for the destruction state are as follows.
AF: Interfacial fracture between the base material and the sealing material, TCF: Breaking leaving a thin layer of the sealing material on the base material, CF: Cohesive failure of the sealing material.

In Table 1, the compounding quantity of each compounding substance is shown in parts by mass. Details of each compounding substance are as follows.
* 1 JER 828, manufactured by Mitsubishi Chemical Corporation.
* 2 Sunsizer EPS, manufactured by Shin Nippon Rika Co., Ltd.
* 3 X-12-812H, manufactured by Shin-Etsu Chemical Co., Ltd.
* 4 Maruo Calcium Co., Ltd., MC coat S-1
* 5 Made by Maruo Calcium Co., Ltd., Calfine 500
* 6 Toagosei Co., Ltd., ARUFON UP1110, weight average molecular weight 2500
* 7 Shin-Etsu Chemical Co., Ltd., KBM1003
* 8 Made by Nitto Kasei Co., Ltd., Neostan U-220H
* 9 Cactus normal paraffin N-11 manufactured by Japan Energy Co., Ltd.

  In Table 2, the compounding amount of each compounding substance is shown in parts by mass. Details of each compounding substance are the same as in Table 1.

  As is clear from the comparison between Comparative Example 1 and Comparative Example 2, the curable composition obtained by adding the epoxy resin to the organic polymer having a crosslinkable silicon group is compared with the composition not containing the epoxy resin, and is immersed in water. The fracture state from AF changes to TCF, and the elongation at break is slightly improved. However, although the fracture state is improved after exposure to heat, the elongation at break is greatly reduced.

  On the other hand, as apparent from Examples 1 to 4 and Comparative Examples 2 to 3, a curable composition obtained by adding a monofunctional epoxy compound to an oxyalkylene polymer having a crosslinkable silicon group in addition to an epoxy resin. It can be seen that the product has further improved elongation at break after immersion in water and improved elongation at break after heat exposure. This is clear from the retention of elongation at break. Thus, in the curable composition of the present invention, the cured product has excellent water resistance and heat resistance.

  According to the sealing method of the siding board of the present invention, since the sealing material has excellent water resistance and heat resistance, it can be used even in severe conditions, and also used for ceramic siding boards that shrink significantly over time. Can do.

Claims (2)

A sealing method for ceramic siding boards, wherein (A) an organic polymer having a hydroxyl group or a hydrolyzable group bonded to a silicon atom as a sealing material and having a silicon-containing group capable of crosslinking by forming a siloxane bond 100 parts by mass, (B) 1 to 100 parts by mass of a compound having two or more epoxy groups in the molecule, (C) a hydroxyl group or hydrolyzable having one epoxy group in the molecule and bonded to a silicon atom 1 to 100 parts by mass of a compound having a group and not having a silicon-containing group that can be crosslinked by forming a siloxane bond, and (D) an adhesion-imparting agent (excluding compounds having two or more epoxy groups in the molecule ) ) A method for sealing a ceramic siding board, wherein a curable composition containing 0.1 to 20 parts by mass is used. 2. The method for sealing a ceramic siding board according to claim 1, wherein the sealing material is applied to the sealing portion of the ceramic siding board without applying a primer.