JPS6315954B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a surface-curing organopolysiloxane composition, and more particularly, it is storage stable under moisture exclusion, and when cured by atmospheric moisture, the surface is cured into a rubber-like elastic body and the interior is uncured. Alternatively, the present invention relates to a surface-curing organopolysiloxane composition that maintains a semi-cured state. An organopolysiloxane whose molecular chain ends are capped with hydroxyl groups is reacted with an amide group-containing organosilicon compound and/or an aminoxy group-containing organosilicon compound as a curing agent, and the entire composition is turned into a rubber-like elastic body at room temperature. Methods for curing are known.
This composition contains a difunctional compound and a trifunctional compound as a curing agent.
By using a polyfunctional compound with higher functionality and changing the ratio, it is possible to change the physical properties over a wide range from low modulus and high elongation to high modulus and low elongation. In particular, low modulus/high elongation mixtures are widely used as architectural sealants due to the excellent weather resistance and fatigue resistance of organopolysiloxanes. As a result of intensive studies on this curing system, the present inventors found that it has excellent storage stability under moisture-blocking conditions, and has a completely different curing state from conventionally known compositions, that is, the surface hardens into a rubber-like elastic body. However, they have discovered a composition that maintains the interior in an uncured or semi-cured state, and have arrived at the present invention. That is,
The present invention consists of (A) 100 parts by weight of an organopolysiloxane having a viscosity of 20 to 1,000,000 centipoise at 25°C and whose molecular chain ends are capped with hydroxyl groups; (B) two or more amides as functional groups in one molecule; 0.5 to 30 parts by weight of an organosilicon compound having a group and/or an aminoxy group, and (C) an organic compound having one functional group selected from an oxime group, a mercapto group, and an amino group.
The present invention relates to a surface-curable organopolysiloxane composition characterized in that the weight ratio of component (C) to component (B) is 0.001 to 5. Component (A) used in the present invention serves as a base material of the present composition, and has the general formula HO[ _-R2SiO ] _-oH (wherein R is the same or different substituted or unsubstituted is a monovalent hydrocarbon group, and n is a value such that the viscosity of the organopolysiloxane is 20 to 1,000,000 centipoise at 25°C.
Dihydroxy-organopolysiloxanes are preferably used. However, some of the linear chains are branched,
Those having three or more hydroxyl groups in one molecule can also be used. R is an alkyl group such as a methyl group, ethyl group, propyl group, or octyl group; an alkenyl group such as a vinyl group or an allyl group;
Aryl groups such as phenyl group, tolyl group, etc.
Examples include halogenated hydrocarbon groups such as chloromethyl group, cyanoethyl group, and 3.3.3-trifluoropropyl group. From the viewpoint of appropriate viscosity balance, it is preferable that 70% or more of R be methyl groups, and more preferably all of R be methyl groups. If the viscosity of the organopolysiloxane is less than 20 centipoise, it will not be possible to impart good physical properties to the rubber-like elastomer after curing, especially flexibility and high elongation. Also,
When it is larger than 1,000,000 centipoise, the viscosity of the composition becomes high, and workability during construction becomes extremely poor. Therefore, a range of 20 to 1,000,000 centipoise is selected, more preferably a range of 200 to 200,000 centipoise. The organosilicon compound of component (B) used in the present invention is a curing agent for crosslinking and curing by reacting with the hydroxyl group of the organopolysiloxane of component (A) in the presence of moisture at room temperature. , it is necessary that one molecule contains two or more amide groups and/or aminoxy groups. If component (A) is an organopolysiloxane with a linear part branched and three or more hydroxyl groups per molecule, the number of functional groups per molecule of component (B) must be 2
2 and 1, 3 or more and 1, 2 and 3 or more and 1, 2 and 3 or more, and 1 functional group that can be used as an additional component. It is also possible to crosslink and cure in combination with. As such an amide group-containing organosilicon compound, dimethylbis(N-methylacetamide)
Silane, dimethylbis(N-ethylacetamide)silane, methylvinylbis(N-methylacetamide)silane, methylvinylbis(N-butylacetamide)silane, methyltris(N-phenylacetamide)silane, vinyltris(N-phenylacetamide)silane,
-ethylacetamido)silane, tetrakis(N
-Amidosilanes such as methylacetamido)silane, amidopolysiloxanes such as

Amidocyclosiloxanes such as [Formula] are exemplified. As aminoxy group-containing organosilicon compounds,
diphenylbis(diethylaminoxy)silane,
Methyltris(diethylaminoxy)silane,

[Formula] Aminoxysilanes such as Si [ONC (C ₂ H ₅ ) ₂ ] ₄ , Aminoxysiloxanes such as

Aminoxycyclosiloxanes such as [Formula] are exemplified. An organosilicon compound containing both an amide group and an aminoxy group in one molecule can also be used, but is usually not used due to the difficulty of synthesis and cost. As the curing agent of component (B), one or more kinds of amide group-containing organosilicon compounds may be used, or one or more kinds of aminoxy group-containing organosilicon compounds may be used. Two types of organosilicon compounds having different functional groups may be used in combination. In order for the curing agent of component (B) to crosslink and harden by reacting with the linear diorganopolysiloxane usually preferably used as component (A) and endblocked with hydroxyl groups at both ends, it is necessary to have an average of 2 in the molecule. The number of amide groups or aminoxy groups must be contained. average 2
This is because a sufficient hardened film cannot be formed on the surface if the amount is less than 1. Of course, the present invention can contain 3 or 4 amide groups or aminoxy groups in one molecule.
Although this includes cases where a curing agent containing more than one amide group or aminoxy group is used as a curing agent, it usually includes one containing two amide groups or aminoxy groups in one molecule, and one containing three or more amide groups or aminoxy groups in one molecule. Mix and use as appropriate. There is no particular limitation on how the functional numbers of the amide group and the functional number of the aminoxy group are combined, but it is necessary to achieve low stress and high elongation, or to improve storage stability when packaged in one package. It is preferable to use the one with higher reaction activity as the bifunctional component in view of the properties and the like. In general, amide group-containing organosilicon compounds are more reactive than aminoxy group-containing organic compounds;
For example, when using an amide group-containing organosilicon compound as a bifunctional component, it is preferable to use an amide group-containing organosilicon compound or an aminoxy group-containing organosilicon compound as a trifunctional or more functional component; When using an aminoxy group-containing organosilicon compound as a component, it is preferable to use an aminoxy group-containing silicon compound as a trifunctional or higher functional component. In order to more effectively achieve the object of the present invention where the surface is cured into a rubber-like elastic body and the interior is uncured or semi-cured (hereinafter referred to as mastic properties), an amide group-containing organic silicone is used as a bifunctional component. It is most preferable to use an organic silicon compound containing an aminoxy group as the trifunctional or higher functional component. The reason for limiting the functional groups of component (B) to amide groups and aminoxy groups is to ensure that the cured composition exhibits sufficiently low stress and high elongation, and also to achieve mastic properties, which is the objective of the present invention. This is because these functional groups need to easily react with the compound of component (C) at room temperature. The appropriate amount of component (B) to be added is that if it is too small, the surface will not harden or the storage stability will be poor when it is packaged in one package, and if it is too large, the curing properties will be poor and it will be economically disadvantageous. 0.5 to 30 parts by weight per 100 parts by weight of organopolysiloxane as component (A).
parts by weight, preferably in the range from 1 to 20 parts by weight. Component (C) used in the present invention is an organic compound having one functional group selected from an oxime group, a hydroxy group, a mercapto group, and an amino group,
It is an important component for achieving the mastic properties that are the object of the present invention. If component (C) is not added,
After crosslinking and curing, the whole becomes a rubber-like elastic body, but (C)
Surprisingly, when the components are added, only the surface exposed to the atmosphere hardens into a rubber-like elastic body, while the interior remains uncured or semi-cured. This is because a part of the amide group or aminoxy group of the amide group-containing organosilicon compound or aminoxy group-containing organosilicon compound of component (B) reacts with component (C), changing into a compound with low curing activity. This is thought to be due to a mixture of these. This reaction is shown, for example, by the following reaction formula. Therefore, as component (C), a compound that reacts with the amide group or aminoxy group of component (B), that is, an organic compound having one functional group selected from an oxime group, a mercapto group, and an amino group, is suitable. . Among these, organic compounds having one oxime group are particularly preferred because they provide better mastic properties. As shown in the reaction formula above, the oxime compound has the general formula

[Formula] (wherein R ¹ is a substituted or unsubstituted monovalent hydrocarbon group, and R ² is a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group). R ¹ is a methyl group,
Alkyl groups such as ethyl, propyl and octyl groups; alkenyl groups such as vinyl and allyl; aryl groups such as phenyl and tolyl;
Examples include chloromethyl group, cyanoethyl group, 3.3.3-trifluoropropyl group, and arylated alkyl group. R ² is a hydrogen atom or R ¹ .
Preferably, both R ¹ and R ² are alkyl groups. Examples of the oxime compound include methyl ethyl ketoxime, dimethyl ketoxime, diethyl ketoxime, methylpropyl ketoxime, ethylpropyl ketoxime, ethyl butyl ketoxime, methyl vinyl ketoxime, cyclohexanone oxime, and benzaldoxime. Examples of the amino compound include butylamine, isobutylamine, pentylamine, octylamine, decylamine, dipropylamine, dibutylamine, methylisobutylamine, propylbutylamine, cyclohexylamine, aniline, piperidine, and toluidine. Examples of the mercapto compound include isopropyl mercaptan, butyl mercaptan, amyl mercaptan, and hexyl mercaptan. When using one of these compounds having a melting point above room temperature, it may be used after being dissolved in a small amount of an organic solvent. The amount of component (C) added varies depending on the molecular weight, activity of the functional group, and amount added of component (B), and the molecular weight, activity of the functional group, and addition method of component (C), but usually (C) The weight ratio of component (B) to component (B) is used in a range of 0.001 to 5. In particular, depending on the method of adding component (C),
The optimal range of the weight ratio of component (C) to component (B) varies. For example, if all ingredients are packaged in one package or
When components (C) and (B) are mixed in advance, as in the case of two packages of component (A), components (B) and (C), the range is preferably from 0.001 to 0.5; For example, if there are two packages containing components (A) and (C) and component (B), or
When components (C) and (B) are mixed at the time of use, as in the case of three packages of component (A), component (B), and component (C), a range of 0.01 to 5 is preferable. In the former case, the (B) and (C) components have sufficient time to react and can react quantitatively, whereas in the latter case, the (B) and (C) components are mixed at the time of use. Therefore, the reaction between component (B) and component (C) occurs simultaneously with the reaction between component (B) and component (C).
This is because a reaction of component (A) also occurs, so in order to effectively react component (B) and component (C), more component (C) is required than in the former case. In addition to components (A) to (C), the mixture of the present invention further contains a finely powdered inorganic material in order to improve the flow characteristics before curing and to impart the necessary mechanical properties as a sealant after curing. Preference is given to adding fillers. Examples of inorganic fillers include fumed silica, calcined silica, precipitated silica, fine quartz powder, calcium carbonate, titanium oxide, diatomaceous earth, aluminum hydroxide, alumina, and silanes,
There are products whose surface has been treated with silazane, low polymerization degree siloxane, organic compound, etc. When used as a building sealant, especially when low stress and high elongation are required, calcium carbonate is preferably used. Furthermore, the composition of the present invention may optionally contain an organosilicon compound having one amide group or aminoxy group in one molecule, an organic solvent, a pigment,
Antifungal agents, flame retardants, plasticizers, thixotropic agents, adhesion promoters, etc. can be added. In the composition of the present invention, components (A), (B), and (C) may be mixed in advance at the time of manufacture and packaged together, or components (A) and (C) may be mixed in advance at the time of manufacture. and (B) component separately (i.e. 2 packages)
However, the two may be mixed just before use, and
Component (A), component (B), and component (C) may be packaged separately (ie, three packages), and the three components may be mixed immediately before use. There are no particular restrictions on the combination of the components (A) to (C). The composition of the present invention can be particularly suitably used as a sealing material for construction, and by taking advantage of its characteristics that the surface hardens into a rubber-like elastic body and the inside becomes unhardened or semi-hardened, it is useful as a mastic-type sealing material. be. Hereinafter, the present invention will be explained with reference to Examples. In the examples, all parts indicate parts by weight. Also,
The following abbreviations were used in the examples. M ₁₅₀ : 150% tensile stress, T _nax : maximum tensile stress, E _nax : elongation at maximum load, CF: cohesive failure,
AF: Adhesive failure, Example 1 α with a viscosity of 12000 centipoise at 25°C,
100 parts of ω-dihydroxydimethylpolysiloxane,
25 parts of light calcium carbonate and 115 parts of heavy calcium carbonate were mixed until uniform. Add dimethylbis(N-methylacetamide) to this mixture.
8 parts of silane, 3 parts of an aminoxy group-containing organosilicon compound represented by the following formula and 0.25 part of methyl ethyl ketoxime were added and mixed until uniform. Using this composition, an H-type joint (adherent mortar, no primer) specified in JIS-A5758 was prepared.
When the product was left to cure at room temperature for two weeks, the surface was cured into a rubber-like elastic body and the inside was in a semi-cured state. This tensile test result is M ₁₅₀ 0.2Kg/cm ² ,
T _nax 0.3Kg/cm ² , E _nax 920%, breaking state CF100%
It was hot. This composition showed no increase in viscosity even after being stored for 6 months under moisture-blocking conditions, exhibiting excellent storage stability, and exhibited physical properties similar to those described above. Example 2 A similar composition to Example 1 was prepared using the compound shown in Table 1 as component (C) in place of methyl ethyl ketoxime, and an H-type joint was prepared. The physical properties after curing after being left at room temperature for two weeks are shown in Table 1. In each case, the cured surface was a rubber-like elastic body, and the inside was in a semi-cured state, but the comparative example was entirely a rubber-like elastic body.

[Table] Example 3 α with a viscosity of 15000 centipoise at 25°C,
ω-dihydroxy-dimethylpolysiloxane 100
30 parts of light calcium carbonate and 70 parts of heavy calcium carbonate were added to the mixture and mixed until uniform. To this mixture were added 10 parts of methylvinylbis(N-ethylacetamido)silane; 2 parts of the compound represented by, dimethyl ketoxime
0.1 part was added and mixed until uniform. A sample similar to Example 1 was prepared using this composition. When it was left to cure at room temperature for two weeks, the surface was cured into a rubber-like elastic body, and the inside was in a semi-cured state. This tensile test result is M ₁₅₀ 0.3Kg/cm ² ,
T _nax 0.4Kg/cm ² , E _nax 1430%, breaking state is CF100
It was %. This composition showed no increase in viscosity even after being stored for 6 months under moisture-blocking conditions, exhibiting excellent storage stability, and exhibited physical properties similar to those described above.

Claims (1)

[Claims] 1 (A) 100 parts by weight of an organopolysiloxane having a viscosity at 25°C of 20 to 1,000,000 centipoise and whose molecular chain ends are blocked with hydroxyl groups (B) Two functional groups in one molecule 0.5 to 30 parts by weight of an organosilicon compound having the above amide group and/or aminoxy group; and (C) an organic compound having one functional group selected from an oxime group, a mercapto group, and an amino group.
A surface-curing organopolysiloxane composition characterized in that the weight ratio of component (C) to component (B) is 0.001 to 5. 2 Component (A) has a viscosity of 200 to 200,000 at 25℃
The composition of claim 1 which is a centipoise α,ω-dihydroxy-dimethylpolysiloxane. 3. Component (B) is a mixture of organosilicon compounds having two and three or more amide groups in one molecule,
A composition according to claim 1. 4. The composition according to claim 1, wherein component (B) is a mixture of organosilicon compounds having two and three or more aminoxy groups in one molecule. 5 Claims in which component (B) is a mixture of an organosilicon compound having two amide groups in one molecule and an organosilicon compound having three or more aminoxy groups in one molecule The composition according to item 1. 6 Component (C) has the general formula [Formula] (wherein R ¹ is a substituted or unsubstituted monovalent hydrocarbon group, and R ² is a hydrogen atom or a substituted or unsubstituted monovalent hydrocarbon group ) The composition according to claim 1, which is an oxime compound represented by: