JP4254471B2 - Curable composition - Google Patents

Description

  The present invention relates to a curable composition that cures in the presence of moisture, and particularly to a curable composition with improved weather resistance.

  So far, polymers having hydrolyzable silicon groups have been used for applications such as sealing materials for buildings, adhesives, coating materials, etc., utilizing the characteristic that the cured product has rubber elasticity, Many compositions have also been reported (Patent Documents 1 to 4). Cured products obtained by curing these polymers are inexpensive and have excellent characteristics, but when exposed to the outdoors over a long period of time, cracks occur on the surface due to the action of ultraviolet rays, ozone, etc. Or had a weather resistance problem that the surface was whitened (discolored).

  In order to improve such weather resistance, conventionally, antioxidants, ultraviolet absorbers, light stabilizers and other anti-aging agents are added, and in addition, polyvinyl cinnamates, unsaturated acrylic compounds, It is known to add an azido resin or the like (Patent Documents 5 to 7). However, the effect of improving weather resistance is not always sufficient, and even when the weather resistance is improved, there are defects such as slowing of curability due to the addition of these substances, and it still has sufficiently satisfactory weather resistance. The means were unknown.

JP-A-3-72527 Japanese Patent Laid-Open No. 62-146959 JP-A-1-131271 Japanese Unexamined Patent Publication No. 1-170681 JP-A-6-65400 JP-A-5-70531 JP-A-8-269315

  In order to improve the above problems, a curable composition containing an organic polymer containing a hydrolyzable silicon group, without significantly impairing properties such as elastic modulus and curability of the cured product, Therefore, there has been a demand for a method for improving surface cracks and surface whitening at a portion (thin layer) where the thickness of the cured product is thin.

  The present invention is an invention that solves the above problems, that is, an organic polymer (A) having at least one hydrolyzable silicon group in the molecule, and 100 parts by mass of the organic polymer (A). On the other hand, it is a curable composition characterized by containing 0.01 to 30 parts by mass of a castor oil polymer and / or a castor oil derivative polymer (B).

  The cured product of the curable composition of the present invention has improved weather resistance without impairing its excellent properties. The obtained cured product can be used as a high-performance material for applications such as sealing materials and adhesives in various fields including construction and automobiles.

In the present invention, the hydrolyzable silicon group in the organic polymer having at least one hydrolyzable silicon group in the molecule is preferably represented by the formula —R ¹ —SiX _e R ² _3-e (where R ¹ represents the number of carbon atoms). 1 to 10 divalent organic groups, R ² is a monovalent organic group having 1 to 20 carbon atoms, X is a hydroxyl group or a hydrolyzable group, and e is an integer of 1 to 3).

Here, R ¹ is preferably an alkylene group having 1 to 10 carbon atoms, and more preferably an alkylene group having 1 to 5 carbon atoms. R ² is preferably a substituted or unsubstituted monovalent organic group having 1 to 20 carbon atoms, and more preferably an alkyl group, fluoroalkyl group or phenyl group having 8 or less carbon atoms. A methyl group and an ethyl group are particularly preferable. X is a hydroxyl group or a hydrolyzable group, and the hydrolyzable group is preferably an alkoxy group having 1 to 5 carbon atoms, a halogen atom, or the like. e is an integer of 1-3. When a plurality of R ² and X are present, they may be the same as or different from each other.

  The hydrolyzable silicon group is preferably at least one in the terminal position in the molecule of the organic polymer. If high elasticity, high weather resistance, etc. are required, there should be 2-8. Is preferred. Mixtures of organic polymers having different numbers of hydrolyzable silicon groups can also be used.

  Preferable examples of the organic polymer having a hydrolyzable silicon group in the present invention include the following. That is, an oxyalkylene polymer having a hydrolyzable silicon group (disclosed in Patent Document 1, etc.), an acrylate polymer having a hydrolyzable silicon group (disclosed in Patent Documents 2-3), a hydrolyzable silicon group A mixture of an oxyalkylene polymer having an alkyl group and a (meth) acrylic acid alkyl ester polymer, a graft polymer of an oxyalkylene polymer having a hydrolyzable silicon group and a (meth) acrylic acid alkyl ester polymer, hydrolyzable silicon And hydrocarbon polymers such as an isobutylene polymer having a group (disclosed in Patent Document 4).

  In the present invention, “(meth) acrylic acid alkyl ester polymer” refers to an acrylic acid alkyl ester polymer, a methacrylic acid alkyl ester polymer, and a copolymer thereof. Further, the graft polymer of oxyalkylene polymer having hydrolyzable silicon group- (meth) acrylic acid alkyl ester polymer is, for example, an alkyl acrylate ester in the presence of an oxyalkylene polymer having hydrolyzable silicon group. And / or by polymerization of alkyl methacrylates and optionally other copolymerizable monomers.

  As the oxyalkylene polymer having a hydrolyzable silicon group at the terminal used in the present invention, conventionally known oxyalkylene polymers can be widely used, and examples of preferred oxyalkylene chains possessed by such oxyalkylene polymers. Examples thereof include polyethylene oxide, polypropylene oxide, polytetramethylene oxide, block copolymers thereof, and random copolymers.

  In addition, these oxyalkylene chains may contain structures other than oxyalkylene for connecting molecular chains, such as urethane bonds, ester bonds, thioether bonds, and siloxane bonds. Such a chemical structure for connecting molecular chains is used when the molecular weight of an oxyalkylene polymer as a raw material is increased to a high molecular weight by a crosslinking reaction.

  As the oxyalkylene polymer having a hydrolyzable silicon group used in the present invention, a polymer having a high molecular weight is preferable because it is excellent in properties such as curability and elongation at break as compared with a polymer having a low molecular weight. However, since it is difficult to directly produce a high molecular weight oxyalkylene polymer having a hydrolyzable silicon group, in the production of such a high molecular weight polymer, a molecular weight of about 3000 to 4000 is relatively easy to obtain. The molecular weight of the oxyalkylene polyol is increased by reacting it with a polyvalent halogen compound. After that, an unsaturated group is introduced at the molecular end, and then the unsaturated group is present in the presence of a catalyst such as platinum. A method of obtaining a polymer having a hydrolyzable silicon group by reacting with a hydrolyzable group-containing silicon hydride compound can be employed.

  In addition, as a method of obtaining an oxyalkylene polymer having a high molecular weight hydrolyzable silicon group, a high molecular weight obtained by polymerizing alkylene oxide in the presence of a catalyst such as a double metal cyanide complex in the presence of an initiator. And having a narrow molecular weight distribution, a method for producing a high molecular weight oxyalkylene polymer having a hydrolyzable silicon group without causing a cross-linking reaction between the molecules. Can also be used.

  As the oxyalkylene polymer having a hydrolyzable silicon group used in the present invention, those having a number average molecular weight (Mn) of 5000 or more and 30000 or less are preferable, and those having a molecular weight of 10,000 to 25000 are more preferable. When the number average molecular weight is less than 5000, the curability of the polymer during the curing reaction is deteriorated, and when the number average molecular weight is more than 30000, the viscosity of the polymer is increased and workability is deteriorated. Furthermore, in the oxyalkylene polymer having a hydrolyzable silicon group of the present invention, when the ratio (Mw / Mn) of the mass average molecular weight (Mw) to the number average molecular weight (Mn) is 1.7 or less, It has a narrow molecular weight distribution, a polymer with relatively few low molecular weight polymers, and has the same viscosity as that of a broad molecular weight distribution. There is a point.

  An oxyalkylene polyol having a narrow molecular weight distribution, which is a raw material for the hydrolyzable silicon group-containing oxyalkylene polymer, is obtained by polymerizing an alkylene oxide to an initiator using a catalyst such as a double metal cyanide complex or cesium hydroxide. Can be easily obtained.

(Polymer oil polymer and / or castor oil derivative polymer (B))
In the present invention, a castor oil polymer and / or a castor oil derivative polymer (B) is used.

  As the castor oil, commercially available castor oils having various purification degrees can be used. Castor oil derivatives include castor oil-derived fatty acid alkyl ester, castor oil-derived fatty acid diol ester, castor oil dehydrated reaction product, castor oil acylated product, castor oil and natural oil and fat transesterification product, etc. Can be mentioned.

  Examples of the alkyl ester of castor oil-derived fatty acid include methyl ester and ethyl ester. Examples of the diol ester of castor oil-derived fatty acid include transesterification products of castor oil and diols such as ethylene glycol and propylene glycol. A dehydrated reaction product of castor oil can be produced by heating castor oil in the presence of an acidic catalyst such as sulfuric acid, phosphoric acid, p-toluenesulfonic acid, and the like. As an acylated product of castor oil, an acetylated product is particularly preferable, and an acetylated product with acetic anhydride is particularly preferable.

  The natural fat / oil in the transesterification product of castor oil and natural fat / fat is preferably a natural fat / fat not containing a hydroxyl group, such as linseed oil, tung oil, rapeseed oil, soybean oil, coconut oil, palm oil, ginger oil, walnut. Preferred are vegetable oils such as oil, rice bran oil, cottonseed oil, camellia oil, olive oil and peanut oil, and animal oils such as beef tallow, pork fat, fish oil and liver oil. The transesterification reaction can be performed by a known method.

  A castor oil polymer and / or a castor oil derivative polymer (B) is obtained by reacting a castor oil and / or a castor oil derivative with an organic peroxide at a temperature of 110 to 180 ° C. in an inert gas atmosphere. Can be obtained. As the organic peroxide, di-t-butyl peroxide is preferable. The degree of polymerization of the polymer (B) is more preferable as the degree of polymerization is higher from the viewpoint of weather resistance.

  As the polymer (B), a castor oil polymer, and a castor oil and a derivative of a castor oil such as a partially dehydrated reaction product of castor oil or a partially acylated castor oil / 3 to 30% by mass / 3 to 3% Examples thereof include a polymer of a 70% by mass mixture. Further, after obtaining a castor oil polymer, a dehydration reaction product obtained by further dehydrating the polymer, a compound obtained by acylating a hydroxyl group in the polymer, and the like can also be used. Further, from the viewpoint of storage stability, those having a hydroxyl group modified by acylation or dehydration reaction are preferred.

  As the polymer of castor oil and / or the polymer (B) of castor oil derivative, those described in Japanese Patent Publication No. 7-49564, Japanese Patent No. 2592622 or Japanese Patent No. 2608764 can be used. Commercial products may also be used, and trade names such as POLYCASTOR # 10 and POLYCASTOR # 30 manufactured by Ito Oil Co., Ltd. can be used. For example, in POLYCASTOR # 10 and POLYCASTOR # 30, since the latter has a higher degree of polymerization, it is more effective in the present invention.

  The usage-amount of a polymer (B) is 0.01-30 mass parts with respect to 100 mass parts of polymers (A), and 0.5-10 mass parts is preferable. 1 to 8 parts by mass is particularly preferable. If it is less than 0.1 parts by mass, the effect of weather resistance is small, and if it exceeds 30 parts by mass, the weather resistance is improved, but the curability is delayed.

  The above compounds may be used alone or in combination of two or more. Moreover, you may use together a compound (B), other fats and oils, and an unreacted castor oil.

  In the present invention, the mechanism in which the polymer (B) improves the weather resistance of the cured product of the curable composition containing an organic polymer having at least one hydrolyzable silicon group in the molecule is not necessarily limited. Although it is not clear, it is considered that the alkyl skeleton in the polymer (B) has some contribution to the weather resistance. In addition, since the molecular weight of the polymer (B) is relatively large, it can be easily taken into the cured body and hardly eluted out of the cured body, so that the effect is considered to be maintained over a long period of time.

(Air-curing compound / photo-curing compound)
The curable composition of the present invention may be used in combination with an air curable compound or a photocurable compound known as a surface modifier for a cured product for improving weather resistance and adhesion of dust over a long period of time.

  Examples of air curable compounds include drying oils typified by paulownia oil and linseed oil, various alkyd resins obtained by modifying the compounds, acrylic polymers modified with drying oils, silicone resins, polybutadiene, carbon number Diene polymers such as 5-8 diene polymers and copolymers, various modified products of the polymers and copolymers (maleinization modification, boil oil modification, etc.), air curable polyester compounds, etc. Can be mentioned.

  Examples of the photocurable compound include a (meth) acryloyl group-containing compound and polyvinyl cinnamate, and an acryloyl group-containing compound is particularly preferable. Specific examples include trimethylolpropane triacrylate, pentaerythritol triacrylate, urethane acrylate, and polyester polyol polyacrylate.

  When using an air curable compound or a photocurable compound, 0.1-50 mass parts is preferable with respect to 100 mass parts of organic polymers (A), respectively.

  When an air curable compound and a photocurable compound are used in combination, there is an effect of improving the weather resistance particularly in a thick portion of the cured product.

(Curing accelerator)
The curable composition of the present invention preferably uses a curing accelerator that accelerates the curing reaction of the hydrolyzable silicon group in the polymer (A). As the curing accelerator, a compound known as a silanol catalyst can be used. Specific examples include the following compounds.

  Divalent tin compounds such as tin 2-ethylhexanoate, tin naphthenate and tin stearate; Organotin carboxylates such as dialkyltin dicarboxylate and dialkoxytin monocarboxylate such as dibutyltin dilaurate, dibutyltin diacetate, dibutyltin monoacetate, dibutyltin maleate, dibutyltin bisacetylacetonate, dibutyltin bisethylacetoacetate, dibutyltin monoacetate Tin chelate compounds such as acetylacetonate monoalkoxide, reaction product of dialkyltin oxide and ester compound, reaction product obtained by further reacting the reaction product with alkoxysilane compound, reaction product of dialkyltin oxide and alkoxysilane compound, dialkyl Tetravalent tin compounds such as tin dialkyl sulfide.

  Examples of the ester compound include phthalic acid esters such as bis-2-ethylhexyl phthalate and diisononyl phthalate, esters of aliphatic and aromatic carboxylic acids, tetraethyl silicate, and partial hydrolysis condensates thereof.

  Bivalent bismuth compounds such as organic carboxylic acid bismuth salts. Aliphatic monoamines such as butylamine, hexylamine, octylamine, decylamine, laurylamine, N, N-dimethyloctylamine, and aliphatic polyamine compounds such as ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, and tetraethylenepentamine. Amine compounds such as aromatic amine compounds, alkanolamines, aminosilane coupling agents such as N- (2-aminoethyl) -3-aminopropyltrimethoxysilane and 3-aminopropyltrimethoxysilane, or carboxylic acids of these amine compounds Etc. and salt.

  Acids such as acetic acid, propionic acid, 2-ethylhexanoic acid, stearic acid, adipic acid, oxalic acid, citric acid, acrylic acid, methacrylic acid, and benzoic acid, and other organic carboxylic acids and phosphoric acid.

  A hardening accelerator can also be used 1 type or in combination of 2 or more types. For example, a divalent tin compound or a divalent bismuth compound is preferably used in combination because the curing acceleration effect is improved by the combined use with an amine and / or an acid. Of these, the combined use with a primary amine is preferred. Further, a divalent tin compound or a combined use of a divalent bismuth compound and a tetravalent tin compound is preferable from the viewpoint of obtaining a composition having a balanced stress relaxation property and low-temperature curability.

  0.01-10 mass parts is preferable with respect to 100 mass parts of polymers (A), and, as for the usage-amount of a hardening accelerator, 0.5-3 mass parts is especially preferable.

(Other additives)
The curable composition of the present invention can further contain and add various known additives. For example, the following known additives can be exemplified. Various calcium carbonates such as heavy calcium carbonate and colloidal calcium carbonate, fillers such as resin balloons and glass balloons. Plasticizers such as phthalates and polyethers. solvent. Dehydrating agents such as vinyltrimethoxysilane and tetraethoxysilane. Thixotropic agents such as hydrogenated castor oil and fatty acid amides. Antioxidants such as hindered phenol compounds, and UV absorbers such as benzotriazole compounds. Light stabilizers such as hindered amine compounds. Modulus modifiers such as phenoxytrimethylsilane and other compounds that generate trimethylsilanol by hydrolysis. Silane coupling agents such as (meth) acryloyl group-containing silanes, amino group-containing silanes, mercapto group-containing silanes, epoxy group-containing silanes, carboxyl group-containing silanes, and combinations of epoxy resins and epoxy resin curing agents Adhesiveness imparting agent. Inorganic pigments such as iron oxide, chromium oxide and titanium oxide. Organic pigments such as phthalocyanine blue and phthalocyanine green.

  Furthermore, for the purpose of giving the cured product a design property, particularly as a sealing material, the surface appearance like granite or granite can be added to the composition by adding micro-particles of a color different from that of the composition. It can also be made to have a cured product. It is also optional to add a known flame retardant or fungicide. It is also possible to add a matting agent used for paint applications.

  Although the curable composition of this invention is demonstrated concretely below, this invention is not limited only to these Examples. In addition, molecular weight distribution (Mw / Mn) in a present Example is a value based on the polystyrene conversion molecular weight measured using the gel permeation chromatography (GPC). The molecular weight of the hydroxyl group-containing oxyalkylene polymer used as a raw material is a molecular weight calculated by calculation based on the number of moles of hydroxyl groups contained and the number of functional groups of the initiator used when polymerizing each polymer.

(Synthesis Example 1)
Propylene oxide was reacted in the presence of a zinc hexacyanocobaltate-glyme complex catalyst using dipropylene glycol as an initiator to obtain a polyoxypropylene diol having Mn of 20000 and Mw / Mn of 1.4. Add 1.05 times mole of sodium methoxide as a methanol solution with respect to the number of moles of hydroxyl groups of this polyoxypropylene diol, distill off methanol under heating and reduced pressure to form sodium alkoxides, and then an excess amount. Allyl chloride was added and reacted. After removing unreacted allyl chloride, the by-product inorganic salt was removed and purified to obtain an oxyalkylene polymer having an allyl group terminal.

  500 g of this polymer was charged into a nitrogen-substituted reaction vessel, and 1,1,3,3-tetramethyldivinylsiloxane platinum complex (hereinafter referred to as VTS complex) was added so that platinum would be 2 ppm, and further 30 minutes. Stir. Next, 6.0 g of dimethoxymethylsilane was added and reacted at 70 ° C. for 5 hours. After completion of the reaction, when volatile substances are removed by reducing the pressure, the hydrolyzable silicon group-containing oxyalkylene polymer having a viscosity at 23 ° C. of 15000 mPa · s and a molecular weight distribution (Mw / Mn) = 1.5 is transparent. 500 g of union (P-1) was obtained.

(Synthesis Example 2)
Viscosity at 23 ° C. using polyoxypropylene triol having Mn of 22000 and Mw / Mn of 1.4 obtained by reacting propylene oxide in the presence of zinc hexacyanocobaltate-glyme complex catalyst with glycerol as an initiator Of 19000 mPa · s was obtained, which was 500 g of a hydrolyzable silicon group-containing oxyalkylene polymer (P-2) that was light yellow and transparent.

(Synthesis Example 3)
600 g of polyoxypropylene diol having Mn of 20000 and Mw / Mn of 1.4 obtained by reacting propylene oxide in the presence of a zinc hexacyanocobaltate-glyme complex catalyst using dipropylene glycol as an initiator, and glycerin Similar to Synthesis Example 1 using 400 g of polyoxypropylene triol having Mn of 22000 and Mw / Mn of 1.4 obtained by reacting propylene oxide in the presence of a zinc hexacyanocobaltate-glyme complex catalyst as an initiator. Then, a hydrolyzable silicon group-containing oxyalkylene polymer (P-3) 500 g having a viscosity at 23 ° C. of 17000 mPa · s and a molecular weight distribution (Mw / Mn) = 1.5 was obtained.

(Synthesis Example 4)
850 g of polyoxypropylene diol having Mn of 6000 and Mw / Mn of 1.2 obtained by reacting propylene oxide in the presence of a potassium hydroxide catalyst using dipropylene glycol as an initiator, and water using glycerol as an initiator. Using 150 g of polyoxypropylene triol having Mn of 6000 and Mw / Mn of 1.2 obtained by reacting propylene oxide in the presence of a potassium oxide catalyst, the viscosity at 23 ° C. was obtained in the same manner as in Synthesis Example 1. Of 15000 mPa · s and a molecular weight distribution (Mw / Mn) = 1.9, 500 g of a light yellow transparent hydrolyzable silicon group-containing oxyalkylene polymer (P-4) was obtained.

  The number average molecular weight (Mn) and molecular weight distribution (Mw / Mn) of the polymers obtained in Synthesis Examples 1, 2, 3 and 4 were analyzed by GPC. The results are shown in Table 1.

(Examples 1-8 and Comparative Examples 3-4)
As shown in Tables 2 to 4, the additives listed in the table were added to the polymers P-1 to P-4 obtained in Synthesis Examples 1 to 4, and kneaded to obtain a composition. The sheet was formed on an aluminum plate. The cured product sheet was obtained by curing at 20 ° C. for 1 week, followed by curing at 50 ° C. and humidity of 65% for 1 week. The shape of the cured product sheet is 100 mm long, 20 mm wide, and 0.2 mm thick. The sheet was irradiated with a sunshine weather meter (manufactured by Suga Test Instruments) for up to 500 hours, and the surface deterioration at that time was visually observed. The surface deterioration was evaluated by whitening (fading) and surface cracking according to the following criteria. The results are shown in Tables 2-4.

  (Whitening) ◯: No whitening, Δ: Some whitening occurred, X: Whitening greatly progressed, XX: The entire surface was whitened.

  (Surface cracks) ○: No cracks, Δ: Some cracks are generated, ×: Cracks progress greatly, XX: There are cracks on the entire surface.

Moreover, the following were used for (1)-(17) in Tables 2-4.
(1) Compound (B-1): A compound corresponding to the polymer (B) of the present invention. Product name POLYCASTOR # 10 (manufactured by Ito Oil Co., Ltd.).
(2) Compound (B-2) A compound corresponding to the polymer (B) of the present invention. Product Name: POLYCASTOR # 30 (Ito Oil Co., Ltd.)
(3) Product name Shirakaka CCR (manufactured by Shiraishi Kogyo Co., Ltd.)
(4) Product name: Whiteon SB (manufactured by Shiroishi Calcium Industry Co., Ltd.)
(5) Product name: R820 (Ishihara Sangyo)
(6) Product name: SUNSOSIZER E-PS (manufactured by Nippon Nippon Chemical Co., Ltd.)
(7) Product name: Disparon # 305 (manufactured by Enomoto Kasei)
(8) Product name: Chinupin 327 (manufactured by Ciba Specialty Chemicals)
(9) Product side: Irganox 1010 (manufactured by Ciba Specialty Chemicals)
(10) Product name: ADK STAB LA67 (Asahi Denka Kogyo Co., Ltd.)
(11) Color paste: 0.5 parts by mass of carbon black, 0.9 parts by mass of Bayferrox 920 (iron oxide pigment manufactured by Bayer), 1.3 parts by mass of Bayferrox 663 (iron oxide pigment manufactured by Bayer), And 3.0 parts by mass of dioctyl phthalate rolled and pasted.
(12) Polyoxypropylene diol having a molecular weight of 3000.
(13) Product name: Disparon # 6500 (manufactured by Enomoto Kasei)
(14) 3- (2-aminoethyl) aminopropyltrimethoxysilane (15) 3-glycidoxypropyltrimethoxysilane (16) vinyltrimethoxysilane (17) dibutyltin oxide / dioctyl phthalate reactant (three shares Manufactured by Machine Synthesis Co., Ltd.)

The curable composition of the present invention can be used for sealing materials, waterproofing materials, adhesives, coating agents and the like. Since it is particularly excellent in the surface weather resistance of the cured product, it is particularly suitable for a sealing material that requires high weather resistance.

Claims (3)

  Castor oil polymer and / or polymer of castor oil derivative (100 parts by weight of organic polymer (A) having at least one hydrolyzable silicon group in the molecule and the organic polymer (A)) A curable composition comprising 0.01 to 30 parts by mass of B). The hydrolyzable silicon group is —R ¹ —SiX _e R ² _3-e (R ¹ is a divalent organic group having 1 to 10 carbon atoms, R ² is a monovalent organic group having 1 to 20 carbon atoms, The curable composition according to claim 1, wherein X is a hydroxyl group or a hydrolyzable group, and e is an integer of 1 to 3. The curable composition according to claim 1 or 2, wherein the organic polymer (A) is an oxyalkylene polymer and has a number average molecular weight of 5,000 to 30,000.