JP2001302929A - Curable composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid the discoloration of a curable composition which contains a chelate titanium compound and a polymer having condensable hydrolyzable groups. SOLUTION: This composition contains (1) 100 pts.wt. polymer having hydrolyzable groups, (2) 0.1-25 pts.wt. cross-linker, and (3) 0.1-10 pts.wt. chelate titanium compound of which the ligand has at least two carbonyl carbon atoms of which at least one has a tertiary alkyl group (including a cycloalkyl group) as a substituent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a curable composition containing a chelate titanate compound which is important as a curing catalyst component such as a room-temperature-curable sealant, and more particularly to a curable composition having excellent catalytic activity and color stability. The present invention relates to a curable composition containing a chelate titanate compound.

[0002]

2. Description of the Related Art Conventionally, there have been known many compositions which cure at room temperature while releasing an alcohol by reacting an alkoxysilyl group upon contact with moisture in the air. Among these, there have been many proposals for curable compositions containing polysiloxanes, especially diorganopolysiloxanes, such as Japanese Patent Publication No. 32-3742. There have been many proposals for compositions containing polyoxyalkylene, such as in JP-A-5-287261. Further, many proposals have been made in JP-A-8-165389.

[0003] Among these room-temperature curable compositions, those using organotitanate as a curable catalyst can be easily converted into a one-pack type composition in which there is no need to mix a main agent and a curing agent immediately before curing. Known in the art, for example, Japanese Patent Publication No. 39-27643 (a siloxane rubber raw material composition comprising hydroxyl-terminated polysiloxane, R _n Si (OR) _4-n type silane and an organotitanium compound), and No. 43-18625 (room temperature curable sealing material composed of hydroxyl-terminated polysiloxane, R _n Si (OR) _4-n type silane and organotitanium compound) and the like. Each of them,
The curable composition was composed of a diorganopolysiloxane having a silanol group at a terminal as a base, an organotrialkoxysilane as a crosslinking agent, and a tetraalkyl titanate as a curing catalyst.

However, this composition has two major problems. First, there was a problem with the cure speed. Specifically, there has been a problem that the curing speed is low, the curing speed is reduced during storage, the mechanical properties after curing are reduced, and finally the curability is lost. Second, there was a problem with the composition manufacturing process. Specifically, when a diorganopolysiloxane having a silanol group at a terminal is brought into contact with a titanate catalyst, an extremely large increase in viscosity occurs temporarily, so that there has been a problem that the production method is very limited. JP-B-39-27643).

In US Pat. No. 3,334,067 or Japanese Patent Publication No. 56-14701, a composition using a chelated alkyl titanate instead of a tetraalkyl titanate (a hydroxyl-terminated polysiloxane, R _n Si (OR A cold-curable composition comprising a _4-n type silane and a chelated alkyl titanate) is disclosed. These compositions solve the problem of extreme viscosity increase when the base polymer and the titanate catalyst come into contact. However, even with these compositions, the problem of the curing speed of the composition as disclosed in the above-mentioned JP-B-39-27643 (the problem that the curing speed is low and the curing speed further decreases during storage). ) Were still left unresolved.

As another method for simultaneously solving the two problems in the means described in JP-B-39-27643, JP-A-55-43119 discloses a method.
A curable composition comprising a diorganopolysiloxane having a dialkoxysilyl group or a trialkoxysilyl group as a base polymer, an organotrialkoxysilane as a crosslinking agent, and a tetraalkyl titanate as a curing catalyst as a basic component is disclosed. ing.

[0007] This composition improves the low cure rate and also allows the tetraalkyl titanate catalyst to be brought into contact with the base polymer without excessive viscosity increase.
The composition can now be prepared and some of the problems of a gradual decrease in cure rate during storage have been alleviated. However, the improvement in the reduction of the curing rate during storage is not sufficient, and when stored at a temperature of about 50 ° C., a clear reduction in the curing rate is observed in the order of several weeks, and especially when the composition is stored in summer. Is often a problem.

[0008] The means described in Japanese Patent Publication No. 5-88866 is to restrict the particulate silica necessary for exhibiting the reinforcing property of the elastomer to hydrophobic silica.
By further improving the storage stability, further, by limiting the terminal to a trialkoxysilyl group, the crosslinking agent to trialkoxysilane, tetraalkoxysilane, or a hydrolyzate thereof, and using a titanium chelate catalyst as a catalyst In order to obtain a higher curing speed.

As another means for solving the problem of storage stability, Japanese Patent Application Laid-Open No. 2-133490 discloses that an organotitanium catalyst is prepared by forming an ethylene bond instead of a siloxane bond to a terminal alkoxysilyl group. Preferred catalysts are described as tetrabutyl titanate, tetraisopropyl titanate, bis (acetylacetonyl) diisopropyl titanate, and 2,5-diisopropoxy-bis (acetylacetonyl) diisopropyl titanium.貯 蔵 -containing storage-stable sealant composition (alkoxy-terminated polyorganosiloxane, R _n Si (O
R) a curable composition comprising a _4-n type silane and an organotitanium catalyst).

[0010] Among these, chelate titanium compounds are particularly excellent in storage stability of the sealant, catalytic activity, curing reaction behavior, etc., but the stability of the titanium compound itself,
In particular, there was a problem in terms of colorability.

That is, this kind of titanium compound having acetylacetonate or ethylacetoacetate as a chelating ligand is originally considered to be almost colorless, but easily discolors under normal storage conditions, Turns yellow to dark brown. This change can occur rapidly in pure compounds alone, or in compositions containing other components as needed, so that sealants containing this type of chelated titanium compound may be yellow or orange in color or have aging effects. There was a problem of yellowing.

In order to address this problem, a method of adding an antioxidant such as an ester of thiocarboxylic acid, di-t-butylphenol, or organic phosphite (Japanese Patent Laid-Open No. 58-719)
No. 51), a method of adding a mercapto compound such as an organic mercaptan or a mercapto-functional silane compound (US Pat. No. 4,962,076), or post-addition of ethyl acetoacetate to a tetraalkoxytitanium-containing composition. To form a chelated titanium compound in situ to reduce the change with time (EP 0 361 803 A2, or JP-A-2-133)
No. 491) has been proposed.

[0013]

However, although various methods for preventing such discoloration have an effect of suppressing yellowing to some extent, they cannot completely suppress the yellowing and have other problems. Including the possibility of causing That is, in the method of adding an antioxidant such as an ester of thiocarboxylic acid or an organic phosphite, there is a problem of odor or corrosive characteristic of a sulfur compound or a phosphite compound. A similar problem occurs in a method of adding a mercapto compound such as an organic mercaptan or a mercapto-functional silane compound. The method of reducing color by forming a chelate titanate compound on the spot, although the time of coloring is delayed,
It does not fundamentally solve the problem of coloring. in this way,
No better solution to the problem of coloring of the chelate titanate compounds or compositions containing them has yet to be given and is essentially non-colored, i.e. a chelate titanate compound with good color stability, as a catalyst. Creation of something that meets the requirements was desired.

US Pat. No. 3,331,067 discloses that in a curable composition containing a hydroxy group-containing polyorganosiloxane and a tetraalkyl titanate, when a chelating titanium compound is used in place of the tetraalkyl titanate, rapid curing of the composition starts. Is disclosed. Numerous examples of this chelated titanium compound have been given, in which the ligand has two carbonyl carbon atoms, at least one of which has a branched alkyl group as a substituent. Wherein the Ti in the chelated titanium compound is
Those which are bidentately arranged on an atom are mentioned. However, this patent only discloses general titanium chelate catalysts, but does not disclose the problem of discoloration when using them and how to solve this problem.

An object of the present invention is to avoid discoloration of a curable composition containing a polymer having a hydrolyzable group and a chelate titanium compound.

[0016]

The present invention comprises the following components:
It is a curable composition containing components. Component: 100 parts by mass of a polymer having a hydrolyzable group; Component: 0.1 to 25 parts by mass of a crosslinking agent having a hydrolyzable group; and Component: a chelate titanium compound, provided that its ligand is two or more. 0.1 to 10 parts by mass having a carbonyl carbon atom, of which at least one carbonyl carbon atom has a tertiary alkyl group (including a cyclic alkyl group) as a substituent.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The above-mentioned components serve as a base polymer of the curable composition of the present invention. This component forms a cured product or a cured film by a condensation reaction with the crosslinking agent of the component. Therefore, a polymer having a hydrolyzable group is used as this component. As long as it satisfies this condition and does not adversely affect the prevention of discoloration of the curable composition over time, which is an effect of the present invention, the chemical type of the polymer of the component, the basic structure of the polymer, The size of the molecule is not particularly limited. Rather, for specific applications, those requirements are selected from the physical properties required of the cured product or cured film.

Accordingly, the chemical types are polysiloxane having a siloxane bond as a basic structure of a main chain, hydrocarbon polymer having a carbon-carbon bond as a basic skeleton of the main chain, and co-polymer of polysiloxane and a hydrocarbon polymer. Any of polymers may be used. The structure of the polymer may be a linear polymer (arbitrarily having a branched structure) or a resin. Since the size of the polymer differs depending on the type of the polymer, the size of the side chain substituent, and the like, which will be described later, for example, in the case of a polydiorganosiloxane, the polymer is applied to the subject of the curable composition of the present invention. In consideration of the workability at the time of curing and the physical properties after curing, a viscosity at room temperature of 20 to 1,000,000 mPa · s is recommended. Beyond this range, the workability will fall below the practical level,
Below this range, the physical properties of the cured product or cured film become insufficient.

The curable composition of the present invention is usually used as a sealant, a coating agent, or the like. In this case, a linear polymer is selected as the basic structure of the component polymer. Of course, this linear polymer may have an arbitrary branched structure. As the type of the basic structure of the polymer, a polysiloxane-based polymer or a hydrocarbon polymer is used. Examples of the hydrocarbon polymer include a polyisobutylene-based polymer, a polypropylene-based polymer, a polyethylene-based polymer, a polyoxyalkylene-based polymer, and a poly (meth) acryl-based polymer.

[Polysiloxane-based polymer] As the polysiloxane-based polymer, polydiorganosiloxane such as polydimethylsiloxane, dimethyl-methylphenylsiloxane copolymer and polymethyltrichloropropylsiloxane, or RSiO _3/2 siloxane unit, R
₂ SiO siloxane unit, R ₃ SiO _1/2 siloxane unit or SiO ₂ siloxane unit (where R is a group selected from unsubstituted or substituted monovalent hydrocarbon group, alkoxy group, or hydroxyl group) Examples thereof include polyorganosiloxane.

Among them, polydiorganosiloxane-based polymers are the most common, and among them, when polydimethylsiloxane is used, preferable characteristics can be obtained as a room-temperature-curable silicone elastomer. RSiO
_3/2 siloxane unit, R ₂ SiO siloxane unit, R ₃
When a polyorganosiloxane containing SiO _1/2 siloxane units and SiO ₂ siloxane units as main components is used, a composition that cures to give a resinous silicone can be obtained. See also the organopolysiloxanes defined in claims 1 et seq. Of JP-A-55-43119.

When the component is a polydiorganosiloxane, a silicone oil represented by the following general formula (I) is typically used. _{^{(R 12 O) 3-k}} R 16 k Si-Y- [R ¹³ ₂ SiO] ^{_{r -R 13 2 Si-Y-}} Si (OR 12) 3-k R 16 k (I) ( herein, R ¹² independently an alkyl group having 1 to 6 carbon atoms, an alkoxy group-substituted alkyl group or a hydrogen atom having 2 to 8 carbon atoms, R ¹³ is an organic group having 1 to 10 carbon atoms independently, R ¹⁶ Is independently a hydrocarbon group having 1 to 8 carbon atoms or a halogenated hydrocarbon group, k is 0.1 or 2, Y is an oxygen atom or a divalent hydrocarbon group having 2 to 5 carbon atoms, r is a positive number such that the viscosity of the silicone oil at 25 ° C. becomes 20 to 1,000,000 mPa · s.) Here, considering the curability, the value of k is desirably 0 or 1. More preferably, k = 0 is recommended.

In the above formula, examples of R ¹³ include:
Alkyl groups such as methyl, ethyl, propyl, butyl, hexyl, octyl, and decyl; cycloalkyl groups such as cyclopentyl and cyclohexyl; alkenyl groups such as vinyl and allyl; aryl groups such as phenyl, tolyl, and naphthyl; Aralkyl groups such as phenylpropyl, and the like; and halogenated hydrocarbon groups such as chloromethyl, trifluoromethyl, chloropropyl, 3,3,3-trifluoropropyl, chlorophenyl, dibromophenyl, tetrachlorophenyl, and difluorophenyl groups And examples of the cyanoalkyl group include β-cyanoethyl, γ-cyanopropyl, and β-cyanopropyl. Also, R
Examples of ¹² include an alkyl group such as methyl, ethyl, propyl, butyl, and hexyl; and an alkoxy-substituted alkyl group such as methoxyethyl, ethoxyethyl, methoxypropyl, and methoxybutyl. R ¹² and R ¹³ each preferably have 1 to 3 carbon atoms, more preferably a methyl group or an ethyl group. Y is an oxygen atom or a divalent hydrocarbon group. Examples of the divalent hydrocarbon group include —CH ₂ CH ₂ —, —CH ₂ CH ₂ CH ₂ —, —C
H ₂ C (CH ₃₎ H- alkylene group such as and the like.

When the component is a polydiorganosiloxane, the viscosity at 25 ° C. is 20 to 1,000,000 mPa · s.
Is preferably within the range. This is because if it is less than 20 mPa · s, it becomes difficult to give the cured elastomer excellent physical properties, particularly flexibility and high elongation, and if it is more than 1,000,000 mPa · s, This is because the viscosity of the composition increases, and the workability during construction is significantly deteriorated. Therefore, more preferably 100 to 500,
000 mPa · s.

The following are specific examples of the polysiloxane. _{^{(R 12 O) 3 Si- (}} CH 2) 2 -Si (CH 3) 2 -
(OSi (CH ₃ ) ₂ ) _y- (CH ₂ ) ₂ -Si (OR
¹² ) ₃ wherein R ¹² is a methyl group or an ethyl group, and y is a polysiloxane having a viscosity at 25 ° C. of 100 to 500,000.
The number is 0 mPa · s.

[Polyoxyalkylene-based polymer] Any polyoxyalkylene-based polymer having an average of more than one hydrolyzable and decomposable group in one molecule can be used as a component in the present invention. The main chain skeleton of the polyoxyalkylene polymer is -R'-O- (where R 'is 2
Represents a valent organic group. ).

The repeating unit is not particularly limited, but may be, for example, —CH ₂ O—, —CH ₂ CH ₂ O
_{-, - CH 2 CH (CH} 3) O -, - CH 2 CH (C 2
_{H 5) O -, - CH} 2 C (CH 3) 2 O -, - CH 2 C
H ₂ CH ₂ CH ₂ O— and the like can be mentioned. Further, the main chain skeleton may be a combination of two or more of them. Specifically, examples of the polyoxyalkylene polymer include polyoxyethylene and polyoxypropylene. In particular, when polyoxypropylene is used, it is possible to obtain a composition which cures at room temperature used for a sealant or the like and becomes an elastomer.

The main chain skeleton of the polyoxyalkylene-based polymer may contain other components such as a urethane-binding component as long as the properties of the polyoxyalkylene-based polymer are not significantly impaired. The urethane binding component is not particularly limited, and examples thereof include aromatic polyisocyanates such as toluene (tolylene) diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate; aliphatic polyisocyanates such as isophorone diisodianate and hexamethylene diisocyanate; Examples thereof include those obtained from a reaction with a polyol having a repeating unit represented by the general formula.

The hydrolyzable group of the polyoxyalkylene-based polymer may be at the terminal of the polyoxyalkylene or at a part of (bonded to) the main chain structure of the polyoxyalkylene. It may include both of them. The polyoxyalkylene may be linear or have a branched structure, and has a molecular weight of 50.
It is preferably about 0 to 50,000 (number average molecular weight). Further, refer to the oxyalkylene copolymer containing at least one reactive silicon in one molecule as defined in claim 1 of Japanese Patent Application Laid-Open No. H11-80533.

[Polyacrylic Polymer] As the component in the present invention, an acrylic polymer having more than one hydrolyzable group on average in one molecule can be used. The hydrolyzable group may be located at the terminal of the acrylic polymer, or may be introduced as a side chain.

Specific examples of the polymethacrylate-based polymer include acrylic polymers such as a polymer mainly composed of polymethyl methacrylate, and a copolymer mainly composed of polymethyl methacrylate, polyethyl methacrylate, polybutyl methacrylate and the like. Examples are based polymers.

The method for producing an acrylic polymer according to the present invention includes, for example, when the hydrolyzable group is an alkoxysilyl group, copolymerization of acrylic acid, methacrylic acid, or a derivative thereof with an alkoxysilyl group-containing vinyl monomer. Can be mentioned.

Further, the acrylic polymer in the present invention may contain a segment formed by a siloxane bond in the main chain as long as the effects of the present invention are not reduced. Further, the acrylic polymer may be a copolymer of the above monomer and other components. Examples of this include:

Aromatic vinyl compounds such as styrene, α-methylstyrene, chlorostyrene, styrenesulfonic acid, 4-hydroxystyrene and vinyltoluene; unsaturated carboxylic acids such as maleic acid, fumaric acid and itaconic acid; Salts thereof (alkali metal salts, ammonium salts, amine salts, etc.), their acid anhydrides (maleic anhydride, etc.), or diesters or halfesters thereof with linear or branched alcohols having 1 to 20 carbon atoms Esters of unsaturated carboxylic acids such as;

Vinyl esters and allyl compounds such as vinyl acetate, vinyl propionate and diallyl phthalate; vinyl compounds containing amino groups such as vinyl pyridine and aminoethyl vinyl ether; itaconic diamide, crotonamide, maleic diamide, fumaric diamide; N
Amide group-containing vinyl compounds such as vinylpyrrolidone; 2-hydroxyethyl vinyl ether, methyl vinyl ether, cyclohexyl vinyl ether, vinyl chloride, vinylidene chloride, chloroprene, propylene, butadiene, isoprene, fluoroolefin maleimide, N
-Other vinyl compounds such as vinylimidazole and vinylsulfonic acid. The molecular weight of the acrylic polymer is 100 from the viewpoint of the physical properties of the cured product.
0 to 30000 (number average amount) is preferable. Further, refer to the acrylic copolymer containing an alkoxysilyl group defined in Claim 1 or the like of JP-A-5-230318.

[Polyisobutylene-based Polymer] As a component of the present invention, polyisobutylene having an average of more than one hydrolyzable group in one molecule can be used. This hydrolyzable group may be located at the terminal of polyisobutylene or may be introduced as a side chain. Molecular weight of polyisobutylene (number average molecular weight)
In consideration of the physical properties of the cured product, the range of 1,000 to 40,000 is preferable. The polyisobutylene may be a copolymer containing the following units in the main chain.

Specifically, 1-butene, 2-butene, 2
-Methyl-1-butene, 3-methyl-1-butene, pentene, 4-methyl-1-pentene, hexene, cyclohexene, vinylcyclohexene, styrene, α-methylstyrene, p-chlorostyrene, dimethylstyrene, monochlorostyrene, Dichlorostyrene, β-pinene, 5
-Aliphatic, alicyclic or aromatic olefins such as ethylidene norbornene and indene; dienes such as butadiene, isoprene and cyclopentadiene; alkenyl ethers such as methyl vinyl ether, ethyl vinyl ether and isobutyl vinyl ether; divinyl dimethyl silane and vinyl trimethyl Silane, 1,3-divinyl-
Alkenylsilanes such as 1,1,3,3-tetramethyldisiloxane, trivinylsilane, tetravinylsilane, allyltrimethylsilane and diallylmethylsilane can be exemplified. Further, JP-A-9-286895
Reference is made to the isobutylene-based copolymers specified in claims 2 et seq. Of the publication and the isobutylene copolymers described in claim 1 et seq. Of JP-A-8-165389.

[Polyethylene Polymer] As the component of the present invention, polyethylene having more than one hydrolyzable group on average in one molecule can be used. The hydrolyzable group may be located at the terminal of the polyethylene or may be introduced as a side chain. The molecular weight (number average molecular weight) of polyethylene is preferably in the range of 1,000 to 40,000 in consideration of the physical properties of the cured product. Further, an alkoxysilyl group is preferable as the hydrolyzable group for this polyethylene. Polyethylene may be a copolymer with another ethylene-based monomer. Further, embodiments of the invention disclosed in Japanese Patent Application Laid-Open No. 9-286895 are described below.

Regarding the polypropylene-based polymer, refer to the following embodiments of the invention in JP-A-9-286895.

When high strength is desired for the cured product obtained from the curable composition of the present invention, a resin is selected as the polymer of the component. The resin may be either a silicone resin or a hydrocarbon resin, and the type of the hydrolyzable group of the resin is not limited as long as the resin satisfies the above-described conditions. As an example of such a resin, a DT type silicone resin having a methoxy group directly bonded to a silicon atom (eg, (CH ₃ SiO
_3/2 ) / ((CH ₃ ) ₂ SiO) / (CH
₃ O _1/2 )), an MQ type silicone resin having a methoxy group directly bonded to a silicon atom (eg, ((CH ₃ ) ₃ S)
_{iO 1/2) / (SiO 4/2)} / (CH 3 O 1/2))) , and the like.

The hydrolyzable group in the polymer of the component contains a silicon atom and has hydrolyzability.
There is no particular limitation as long as by-products that adversely affect the properties of the cured product are generated by a series of curing reactions. Examples of such hydrolyzable groups include, but are not limited to, the following.

(1) Representative examples of the above hydrolyzable group in the present invention include the following (A) or (B). _{(A) X a R 3-} a Si- or _{(B) X b R 2-} b
Si = (where a is 1, 2 or 3, b is 1 or 2, X is independently an alkoxy group having 1 to 6 carbon atoms or an alkoxy group substituted with 2 to 8 carbon atoms. , R independently represent a hydrocarbon group having 1 to 8 carbon atoms or 1
To 8 halogenated hydrocarbon groups, where “=” represents two bonds and “≡” represents three bonds. same as below. ). In addition, XSi≡ (X has the same meaning as described above) can also be used. (2) In addition to the above, the following (C) to (E) are exemplified. (C) W _a R _3-a Si- (a is 1, 2 or 3
), (D) W _b R _2-b Si = (b is 1 or 2) or (E) WSi≡ (where R represents the same meaning as described above, W represents a hydroxyl group, an acyloxy group [ R'C (=
O) -O-, R 'is an alkyl group] (Representative examples are acetoxy group), alkenyloxy group (Representative examples are propenoxy group _{[CH 2 = C (CH 3)} -O- ]), amino group, amido group, An aminooxy group, a mercapto group, an aryloxy group (R ″ O—, R ″ is an aryl group) (a typical example is a phenoxy group), or R ′ ″ ₂ C = N—O— [R ′ ″ Aliphatic hydrocarbon group]. )

The hydrolyzable group of the polymer of the component has the above-mentioned structure, and the silicon atom of the hydrolyzable group may be bonded to the terminal of the main chain of the polymer. The silicon atom of the functional group may be part of the main chain of the polymer. Further, the terminal atom on the main body side of the polymer and the silicon atom of the hydrolyzable group may be directly bonded, or an alkylene group or the like may be interposed therebetween.

The number of these hydrolyzable groups of the polymer of the component refers to the functionality of the cross-linking agent of the component used in combination (here, the number of hydrolyzable groups per silicon atom). Although it depends on), it is desirable to have more than one polymer on average in one polymer molecule in order to obtain a cured product.

These hydrolyzable groups may be bonded to any polymer as long as the curability and the properties of the cured product or cured film can be maintained at the required levels. It is preferable to bond to at least both ends from the viewpoint of curability. When the hydrolyzable group is an alkoxysilyl group, specifically, there may be a trialkoxysilyl group, a dialkoxy (alkyl) silyl group or an alkoxy (dialkyl) silyl group. Alkoxy (alkyl)
A silyl group is desirable, and a trialkoxysilyl group is particularly recommended when rapid curability is required.

The above components act as a crosslinking agent in the curable composition of the present invention. As the crosslinking agent, a silane compound having an average of two or more hydrolyzable groups in one molecule or a partially hydrolyzed condensate thereof is preferable. Usually, a compound represented by the following general formula (II) is used, but is not limited thereto.

General formula (II): R ¹⁴ _c SiR ¹⁵ _4-c (where R ¹⁴ is a hydrocarbon group having 1 to 8 carbon atoms, R ¹⁵ is an alkoxy group having 1 to 6 carbon atoms, 2 to 2 carbon atoms) 8 substituted alkoxy, hydroxyl, acyloxy, alkenyloxy, aryloxy or oxime groups (R
[The R is an aliphatic hydrocarbon group] ₂ C = N-O- is a), c is 0 or 1. Or a partially hydrolyzed condensate thereof.

The component used in the present invention is preferably a compound represented by the general formula R ¹⁹ _d Si (OR ²⁰ ) _4-d (where R ¹⁹ is defined as R ¹⁴ and R ²⁰ has 1 to 6 carbon atoms). Or an alkyl group substituted with an alkoxy group having 2 to 8 carbon atoms,
Is 0 or 1. )) Or a partially hydrolyzed condensate thereof.

Specific examples of components include tetrafunctional alkoxysilanes such as tetramethoxysilane, tetraethoxysilane, and methylcellosolve orthosilicate; methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, vinyltrimethoxysilane, Trifunctional alkoxysilanes such as phenyltrimethoxysilane and methyltrimethoxyethoxysilane; and partially hydrolyzed condensates thereof. These may be used alone or in combination of two or more. Further, bifunctional alkoxysilanes such as diphenyldimethoxysilane and dimethylmethoxysilane may be added in order to impart low modulus to the rubber elastic body after curing.

As described above, the amount of the component is 10
0.1 to 25 parts by mass relative to 0 parts by mass, preferably in the range of 1 to 20 parts by mass, more preferably 1 to 20 parts by mass.
The range is 10 parts by mass. If the added amount of the component is too small, the composition will not cure sufficiently, or it will be easily packaged and thickened or gelled during storage, and if it is too large, the curing will be slow or economically disadvantageous. Because it becomes.

The component is a curing catalyst for the curable composition of the present invention. This is composed of a chelated titanium compound and does not cause discoloration of the curable composition over time while being practically curable. A chelate titanium compound exhibiting such performance has a ligand having two or more carbonyl carbon atoms, of which at least one carbonyl carbon atom has a tertiary alkyl group (such as a cyclic alkyl group as a substituent). ), And typically a structure having the following formula (a) or formula (b) can be used.

[0052]

Embedded image

Here, R ¹ is -CR ⁵ R ⁶ R ⁷ (R ⁵ ,
R ⁶ and R ⁷ are each independently an alkyl group having 1 to 6 carbon atoms)
Or

Embedded image Be a cyclic alkyl group having the structure; A is selected from -R ³ or -OR ⁴ (wherein R ³ is a halogenated hydrocarbon group or a hydrocarbon group having 1 to 8 carbon atoms of 1 to 8 carbon atoms (A part of the hydrogen atoms of the hydrocarbon group is replaced by halogen atoms), and R ⁴ is a hydrocarbon group having 1 to 8 carbon atoms, a halogenated hydrocarbon group having 1 to 8 carbon atoms (carbon Selected from hydrogen atoms having a part of hydrogen atoms substituted with halogen atoms) or perfluoroalkyl groups having 1 to 8 carbon atoms (all hydrogen atoms of the alkyl groups are substituted with fluorine atoms); R ⁸ is a hydrogen atom, a hydrocarbon group having 1 to 8 carbon atoms, or a halogenated hydrocarbon group having 1 to 8 carbon atoms (a part of the hydrogen atoms of the hydrocarbon group is substituted with a halogen atom) R ¹⁰ is a hydrocarbon group having 1 to 8 carbon atoms; R ¹⁷ is a hydrocarbon group having 1 to 3 carbon atoms or a hydrogen atom;
Is an integer of 1 to 6.

The above structure

Embedded image Is bonded to the carbonyl carbon, and 3
At least two of the two —CH ₂ — contribute to ring configuration.

The chelated titanium catalyst is used in the range of 0.1 to 10 parts by mass based on the components. If the amount is less than this range, it is difficult to ensure practical curability. The upper limit of the amount of addition is not critical, as long as the desired curability is met, but the above range is considered in consideration of the storage stability during storage until the curable composition of the present invention is cured in air. It becomes a practical range. When emphasis is placed on ensuring general curability and storage stability, a range of 0.3 to 6 parts by mass, more preferably 1 to 5 parts by mass, is recommended.

Specific examples of the components are shown below. First, an example of the one represented by the following equation (a) will be described.

[0057]

Embedded image

In the above formula, examples of R ¹⁰ include ethyl, n-propyl, i-propyl, t-butyl, n-butyl, s-pentyl, t-pentyl,
An allyl group _{(CH 2 = CH-CH 2} -) can be mentioned, R ¹
Is an example of a t-pentyl group (CH ₃ CH ₂ C (CH
₃ ) _2- ), t-butyl group (CH ₃ -C (CH ₃ )
_2- ), and examples of A include a methyl group, a methoxy group, an ethyl group, an ethoxy group, i-propyl (oxy)
Group, t-butyl (oxy) group, n-butyl (oxy)
Group, s-pentyl (oxy) group, t-pentyl (oxy) group, allyl (oxy) group (CH ₂ ＣＨCH—CH ₂ —
(O-)), and examples of R ⁸ include a hydrogen atom and a methyl group.

Examples of compounds include: diisopropoxytitanium bis (methyl-3-oxo-4,4-dimethylhexanoate)

Embedded image

Di-tert-butoxytitanium bis (ethyl-3-oxo-4,4-dimethylhexanoate)

Embedded image

Next, as specific examples of the components, those represented by the following formula (b) will be described.

[0062]

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In the above formula, examples of R ¹⁷ include a hydrogen atom and a methyl group. A, R ¹ , R ⁸
Can be the same as those described above for formula (a).

Examples of the compound include 2,3-dimethyl-
2,3-dioxybutane titanium bis (methyl pivaloyloacetate)

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2-methyl-2,4-dioxypentanetitanium bis (methylpiberoyloacetate)

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1,3-dioxypropanetantanium bis (methylpivaloyl acetate)

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1,2-dioxyethane titanium bis (methyl-3-oxo-4,4-dimethylhexanoate)

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2,3-dimethyl-2,3-dioxybutanetitanium bis (methyl-3-oxo-4,4-dimethylhexanoate)

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2-methyl-2,4-dioxypentane titanium bis (methyl-3-oxo-4,4-dimethylhexanoate)

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The chelate titanium compound used in the present invention can be synthesized, for example, by mixing a tetraalkoxy titanium and a ketone compound at room temperature. As an example of the ketone compound, ethyl 3- (1-adamantyl) -3-oxopropionate can also be mentioned.

In the present invention, hydrophobic silica can be added according to the application. As a result, the composition of the present invention can be provided with improved storage stability and a good surface film formation rate, and can have appropriate viscosity and rubber properties. This silica is preferably surface-treated. Examples of the silica surface treatment agent include organosilazanes, organocyclosiloxanes, organochlorosilanes, organoalkoxysilanes, and low-molecular-weight linear siloxanes, such as organosilicon compounds conventionally known as hydrophobic treatment agents for silica. Is preferred. In addition, two or more surface treatment agents may be used in combination for the purpose of adjusting the surface film formation rate and the flow characteristics. As silica, dry silica is preferred from the viewpoints of storage stability of the composition of the present invention, imparting appropriate viscosity, imparting rubber properties, and water content.

The addition amount of the silica is 1 to 200 parts by mass based on 100 parts by mass of the component, but preferably 3 to 200 parts by mass.
３０30 parts by mass. If the amount is too large, the viscosity of the composition becomes too high, resulting in poor workability during mixing and application. If the amount is too small, the physical properties of the cured rubber are not improved.

The composition of the present invention, in addition to the above components and silica, further improves the flow characteristics before curing and imparts necessary mechanical properties to the rubber-like elastic body after curing, if necessary. For this purpose, a finely powdered inorganic filler can be added. Inorganic fillers include fine quartz powder, calcium carbonate, fumed titanium dioxide, diatomaceous earth, aluminum hydroxide, particulate alumina, magnesia, zinc oxide, zinc carbonate, and silanes, silazanes, and low-polymerization siloxanes. And surface-treated with an organic compound. Further, an organic solvent, a fungicide, a flame retardant, a heat-resistant agent, a plasticizer, a thixotropy-imparting agent, an adhesion promoter, a curing accelerator, a pigment, and the like can be added to the composition of the present invention.

The composition of the present invention can be obtained by mixing the component (1) or the component (2) and silica and, if necessary, various additives in a state where moisture is blocked. The obtained composition is stored as it is in a closed container, and cures to a rubbery elastic body by exposing it to moisture in the air at the time of use.
It can be used as a so-called one-package room temperature curable organopolysiloxane composition.

Hereinafter, embodiments of the present invention will be described. (Aspect 1) A curable composition containing the following components. Component: 100 parts by mass of a polymer having a hydrolyzable group Component: 0.1 to 25 parts by mass of a crosslinking agent having a hydrolyzable group; and Component: a chelate titanium compound, provided that its ligand is two or more carbonyls 0.1 to 10 parts by mass having carbon atoms, of which at least one carbonyl carbon atom has a tertiary alkyl group (including a cyclic alkyl group) as a substituent.

(Embodiment 2) The curable composition according to embodiment 1, wherein the component is a polydiorganosiloxane or a hydrocarbon polymer.

(Embodiment 3) The above component is (A) X _a R _3-a
Si- or _{(B) X b R 2-} b Si = ( here, a is 1, 2 or 3, b is 1 or 2, X independently having 1 to 6 carbon atoms an alkoxy group or a carbon R 2 is a hydrocarbon group having 1 to 8 carbon atoms or a halogenated hydrocarbon group having 1 to 8 carbon atoms, and “=” represents two bonds The curable composition according to embodiment 1, which is a polydiorganosiloxane or a hydrocarbon polymer having an average of more than one hydrolyzable group represented by the following formula:

(Embodiment 4) The above-mentioned component has the general formula (I):
_{^{(R 12 O) 3-k}} R 16 k Si-Y- [R ¹³ ₂ SiO] _r -
_{^{R 13 2 Si-Y-Si}} (OR 12) 3-k R 16 k ( here,
R ¹² is independently an alkyl group having 1 to 6 carbon atoms, 2 to 8 carbon atoms.
An alkoxy-substituted alkyl group or a hydrogen atom,
R ¹³ is independently an organic group having 1 to 10 carbon atoms, R ¹⁶ is independently a hydrocarbon group having 1 to 8 carbon atoms or a halogenated hydrocarbon group having 1 to 8 carbon atoms, and k is 0, 1 or 2; Y is an oxygen atom or a divalent hydrocarbon group having 2 to 5 carbon atoms; and r is a compound having a viscosity of 20 to 1 at 25 ° C. , 000,000,0
00 mPa · s), and the component is represented by the general formula (II): R ¹⁴ _c SiR
¹⁵ _4-c (where R ¹⁴ is a hydrocarbon group having 1 to 8 carbon atoms; R ¹⁵ is an alkoxy group having 1 to 6 carbon atoms;
Is an alkoxy group, an alkoxy group, a hydroxyl group, an acyloxy group, an alkenyloxy group, an aryloxy group or an oxime group (R ₂ C = NO— [R is an aliphatic hydrocarbon group]), and c is 0 or It is one. The curable composition according to embodiment 1, which is the silane represented by the formula (1) or a partially hydrolyzed condensate thereof.

(Embodiment 5) The curable composition according to any one of Embodiments 1 to 4, wherein the chelate titanium compound as the component is one represented by the structure of the following formula (a).

Embedded image [Where R ¹ is -CR ⁵ R ⁶ R ⁷ (R ⁵ , R ⁶ , R ⁷
Is independently an alkyl group having 1 to 6 carbon atoms) or

Embedded image Be a cyclic alkyl group having the structure; A is selected from -R ³ or -OR ⁴ (wherein R ³ is a halogenated hydrocarbon group or a hydrocarbon group having 1 to 8 carbon atoms of 1 to 8 carbon atoms (A part of the hydrogen atoms of the hydrocarbon group is replaced by halogen atoms), and R ⁴ is a hydrocarbon group having 1 to 8 carbon atoms, a halogenated hydrocarbon group having 1 to 8 carbon atoms (carbon Selected from hydrogen atoms having a part of hydrogen atoms substituted with halogen atoms) or perfluoroalkyl groups having 1 to 8 carbon atoms (all hydrogen atoms of the alkyl groups are substituted with fluorine atoms); R ⁸ is a hydrogen atom, a hydrocarbon group having 1 to 8 carbon atoms, or a halogenated hydrocarbon group having 1 to 8 carbon atoms (a part of the hydrogen atoms of the hydrocarbon group is substituted with a halogen atom) R ¹⁰ is a hydrocarbon group having 1 to 8 carbon atoms; R ¹⁷ is a hydrocarbon group having 1 to 3 carbon atoms or a hydrogen atom;
Is an integer of 1 to 6. ]

(Embodiment 6) The curable composition according to any one of Embodiments 1 to 5, further comprising 1 to 200 parts by mass of hydrophobic silica based on 100 parts by mass of the component.

(Embodiment 7) Curing according to any one of Embodiments 1 to 6, wherein the tertiary alkyl group which the carbonyl carbon atom of the chelate titanium compound as the component has as a substituent is a t-butyl group or a t-pentyl group. Composition.

(Embodiment 8) A curable composition containing the following components and hydrophobic silica: Component: General formula (I): (R ¹² O) ₃ Si—Y— [R ¹³
₂ SiO] _r -R ¹³ ₂ Si-Y-Si (OR ¹² ) ₃ (where R ¹² is a methyl group or an ethyl group, R ¹³ is a methyl group, and Y is 2 to 5 carbon atoms. Is a monovalent hydrocarbon group, and r is such that the viscosity of this polymer at 25 ° C is 20 to
100 parts by mass of a polymer represented by a positive number such as 1,000,000 mPa · s); component: general formula: R ¹⁹ _d Si (OR ²⁰ ) _4-d (here, R ¹⁹ Is a hydrocarbon group having 1 to 8 carbon atoms;
²⁰ is an alkyl group having 1 to 6 carbon atoms or an alkyl group substituted with an alkoxy group having 2 to 8 carbon atoms, and d is 0 or 1. )) Or 0.1 to 25 parts by mass of a partially hydrolyzed condensate thereof; component: 0.1 to 10 parts represented by the following structure (a) or (b):
Parts by mass,

Embedded image (Where R ¹⁰ is an alkyl group having 1 to 3 carbon atoms;
Is 1, 2 or 3, R ¹ is a tertiary butyl group or a tertiary pentyl group, and A has 1 to 1 carbon atoms.
A hydrocarbon group having 6 or a perfluoroalkyl group having 1 to 4 carbon atoms, and R ⁸ is a hydrocarbon group having 1 to 6 carbon atoms. 1) to 200 parts by mass of hydrophobic silica.

[0083]

According to the curable composition of the present invention, discoloration of the composition during storage under sealed conditions, which is observed in a conventional one-pack dealcoholizable curable composition at room temperature, is greatly suppressed. It also has excellent curability and storage stability, and physical properties after curing are equivalent to or better than conventional ones.
Therefore, it is particularly useful for applications such as, for example, building sealing materials, coating agents for furniture, decorative articles and the like.

[0084]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited by these. The polydiorganosiloxane A used in the following Examples and Comparative Examples was
Formula (C ₂ H ₅ O) ₃ Si—CH ₂ CH ₂ —SiMe ₂ —
_{O- (SiMe 2 O) x -SiMe} 2 -CH 2 CH 2 -
It is a polydimethylsiloxane represented by Si (OC ₂ H ₅ ) ₃ and having a viscosity at 25 ° C. of 20,000 mPa · s.

[Measurement of TFT (Tack Free Time)]
In the following Examples and Comparative Examples, the TFT was prepared by applying the curable composition of the present invention to a substrate (PET film) to a thickness of about 3 mm, and applying the composition at 20 ° C. and a relative humidity of 55%. A polyethylene film was placed thereon, and a 30 g weight was further placed on the polyethylene film for 30 seconds. Then, the polyethylene film was peeled off, and the time until the curable composition did not adhere (elapsed time after application) was measured. The measurement is performed every 1 minute from the initial period (elapsed time 0 minutes) to 10 minutes (peeling off the polyethylene film every 1 minute elapsed time; the same applies hereinafter), and 2 times during the elapsed time 10 minutes to 20 minutes. The test was performed every minute, every 5 minutes from 20 minutes to 160 minutes elapsed.

(Examples 1 to 12, Comparative Examples 1 to 3) Sample Preparation The tetraorganotitanate and ketone compound shown in Table 1 were mixed at room temperature for 3 hours, and each of the resulting chelate titanium compound catalysts (components) was mixed with the following polydiorganosiloxane A (component) and alkoxy-functional crosslinking agent (component). ) To obtain a sample. The mixing ratio was as follows. Chelate titanium compound catalyst Tetraorganotitanate 1 mol Ketone compound Molar ratio shown in Table 1 Sample (curable silicone composition) Polydiorganosiloxane A 93% by mass (100 parts by mass) Methyltrimethoxysilane 5% by mass (5.37% by mass) Parts) Chelate titanium compound catalyst 2% by mass (2.15 parts by mass)

2. Test contents The samples were stored under the following conditions, and the discoloration and transparency over time were visually confirmed. In addition, tack free time (TFT) was measured to confirm curability. Storage conditions Temperature: 50 ° C. Duration: 28 days Atmosphere: Stored in a glass bottle tightly closed.

3. Test results The test results are shown in Table 1 below.

[0089]

[Table 1]

[0090]

[Table 2]

As is clear from Table 1, all of the samples of Examples 1 to 9 to which the chelate titanium catalyst using methyl pivaloyl acetate was applied were colorless and transparent from the beginning, and the discoloration over time and the deterioration of the transparency were low. I couldn't see it. On the other hand, in Comparative Example 1 in which a chelate titanium catalyst using ethyl acetoacetate was applied, discoloration occurred from the beginning, and deterioration in transparency was recognized. The curability was maintained at a practical level. In Examples 10 and 11 using dipivaloylmethane instead of methylpivaloyl acetate, the same results as in the above example were obtained. Example 12 using ethyl 3- (1-adamantyl) -3-oxopropionate instead of methyl pivaloyl acetate also gave similar results. On the other hand, in Comparative Examples 2 and 3, in which ethyl benzoyl acetate or ethyl isobutyryl acetate was used instead of methyl pivaloyl acetate, discoloration occurred from the beginning, and deterioration in transparency was observed.

Claims (4)

[Claims] 1. A curable composition comprising the following components. Component: 100 parts by mass of a polymer having a hydrolyzable group Component: 0.1 to 25 parts by mass of a crosslinking agent having a hydrolyzable group; and Component: a chelate titanium compound, provided that its ligand is two or more carbonyls 0.1 to 10 parts by mass having carbon atoms, of which at least one carbonyl carbon atom has a tertiary alkyl group (including a cyclic alkyl group) as a substituent. 2. The curable composition according to claim 1, wherein the component is a polydiorganosiloxane or a hydrocarbon polymer. 3. The curable composition according to claim 1, wherein the chelate titanium compound as the component is represented by the following formula (a) or (b). Embedded image [Where R ¹ is -CR ⁵ R ⁶ R ⁷ (R ⁵ , R ⁶ , R ⁷
Is independently an alkyl group having 1 to 6 carbon atoms) or Be a cyclic alkyl group having the structure; A is selected from -R ³ or -OR ⁴ (wherein R ³ is a halogenated hydrocarbon group or a hydrocarbon group having 1 to 8 carbon atoms of 1 to 8 carbon atoms (A part of the hydrogen atoms of the hydrocarbon group is replaced by halogen atoms), and R ⁴ is a hydrocarbon group having 1 to 8 carbon atoms, a halogenated hydrocarbon group having 1 to 8 carbon atoms (carbon Selected from hydrogen atoms having a part of hydrogen atoms substituted with halogen atoms) or perfluoroalkyl groups having 1 to 8 carbon atoms (all hydrogen atoms of the alkyl groups are substituted with fluorine atoms); R ⁸ is a hydrogen atom, a hydrocarbon group having 1 to 8 carbon atoms, or a halogenated hydrocarbon group having 1 to 8 carbon atoms (a part of the hydrogen atoms of the hydrocarbon group is substituted with a halogen atom) R ¹⁰ is a hydrocarbon group having 1 to 8 carbon atoms; R ¹⁷ is a hydrocarbon group having 1 to 3 carbon atoms or a hydrogen atom;
Is an integer of 1 to 6. ] 4. The tertiary alkyl group on the carbonyl carbon atom of the chelate titanium compound of the above component is t-
The curable composition according to any one of claims 1 to 3, which is a butyl group or a t-pentyl group.