JPS58157860A - Organosiloxane composition that becomes applicable after cold curing - Google Patents

Abstract

PURPOSE:The titled composition that contains a specific dialkoxysilane or its partially hydrolytic condensate, thus facilitating the paint coating on silicone rubber surfaces after cold curing. CONSTITUTION:The objective composition comprises (A) 100pts.wt. of organopolysiloxane having a viscosity of 20-1,000,000 centipoise at 25 deg.C, (B) 0.5- 30pts.wt. of organosilicon compounds having 2 or more amide groups and/or aminoxy groups in one molecule as functional groups, (C) 0.05-15pts.wt. of dialkoxysilane of the formula (X is monovalent group selected from mercapto, amino, acryloxy and epoxy; R<1> is divalent organic group; R<2> and R<3> is monovalent hydrocarbon) or its partially hydrolytic condensate.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a room-temperature-curable organopolysiloxane composition, and in particular, to a room-temperature-curable organopolysiloxane composition that can be easily coated with a paint on the silicone rubber surface after room-temperature curing. The present invention relates to siloxane compositions.

Conventionally, an organopolysiloxane whose 9 molecular terminals are blocked 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 converted into a rubber-like elastic body at room temperature. Methods for curing are known. This composition uses 2 as a curing agent.
By using a functional compound and a trifunctional or higher polyfunctional compound and changing the ratio, physical properties can be changed over a wide range from low modulus and high elongation to high modulus and low elongation. I can do it. Especially low modulus $5.
High elongation type compositions are widely used as architectural sealants due to the excellent weather resistance and fatigue resistance of organopolysiloxanes.

However, one major drawback of these silicone sealants is that they cannot be painted (applying or adhering paint, the same applies hereinafter) to the cured silicone rubber surface. Due to this drawback, despite its excellent properties.

The applications of silicone sealants have been limited.

We believe that this is a major drawback of silicone-based sealants. As a result of considering this improvement in paintability,
We have now invented a room-temperature-curable organopolysiloxane composition that can be well coated with a paint on the silicone rubber surface after room-temperature curing.

In other words, one aspect of the present invention is.

Viscosity at 25°C is 20~i, oo o, o o
100 parts by weight of organopolysiloxane which is centiboid and has 9 molecular chain ends blocked with hydroxyl groups
Two or more amide groups and /f as functional groups in the molecule
or having an aminoxy group C) General formula R2 X -R' -Si (OR3)2 (wherein, Monovalent group R1 is a divalent organic group, R2 and R
3 represents a substituted or unsubstituted monovalent hydrocarbon group. The present invention relates to an organopolysiloxane composition which can be coated after being cured at room temperature and is comprised of 0.05 to 15 parts by weight of a dialkoxysilane represented by the following formula or a partially hydrolyzed condensate thereof.

is an unsubstituted monovalent hydrocarbon group, and n is such that the viscosity of the organopolysiloxane is 20 to 1.000.0 at 25°C.
α, ω expressed as 00 centivoise)
-dihydroxy-organopolysiloxanes are preferably used. However, it is also possible to use a form in which a part of the linear chain is branched and the number of hydroxyl groups in one molecule is three or more. 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, an aryl group such as a phenyl group or a tolyl group, or a chloromethyl group.

Examples include halogenated hydrocarbon groups such as cyanoethyl group, 3.3.3-)lifluoropropyl group, etc.9 Ease of synthesis, required mechanical properties after curing, and appropriateness of uncured composition From the viewpoint of viscosity balance, etc., it is preferable that 70 or more of R's are methyl groups, and it is further preferable that all of R's are methyl groups. The viscosity of the organopolysiloxane is less than 1%, with excellent physical properties and a rubber-like elastic body after curing.

It cannot provide flexibility and high elongation. Also, 1
If it is larger than 1,000,000 centivoise, the viscosity of the 9 composition becomes high, and the workability during construction becomes extremely poor. Therefore, a range of 20 to 1,000,000 centiboise is selected, more preferably a range of 2'00 to 200,000 centiboise.

The organosilicon compound as component (B) used in the present invention is:
Cross-links by reacting with the hydroxyl groups of the organopolysiloxane as a binder component in the presence of moisture at room temperature.

It is a curing agent for curing, and therefore, it is necessary to contain two or more amide groups and/or aminoxy groups in one molecule. If 7. When using an organopolysiloxane having a straight chain partially branched and having three or more hydroxyl groups in one molecule as a captive component, the number of functional groups in one molecule of component (B) is only two, A combination of 2 pieces and 3 or more pieces can also be used to make the rack m or m.

°As such amide group-containing organosilicon compounds,
Dimethylbis(N-methylacetamide)silane, dimethylbis(N-ethylacetamide)silane, methylvinylbis(N-methyl, acetamido)silane, methylvinylbis(N-butylacetamide)silane, methyltris(N-phenylacetamide) Silane, vinyltris(N-ethylacetamido)silane.

Amidosilanes such as tetrakis(N-methylacetamido)silane.

l　　　　　II C) t30 Ql-IS　O amidosiloxanes such as.

Amidocyclosiloxanes are exemplified.

As an aminoxy group-containing organosilicon compound.

Diphenylbis(diethylaminoxy)silane.

Aminoxysiloxanes such as.

D1 Aminoxycyclosiloxanes such as fZ are exemplified.

Organosilicon compounds containing both an amide group and an aminoxy group in one molecule can also be used, but they are usually not used because of the difficulty in 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.

■The curing agent of component (A) reacts with the linear diorganopolysiloxane endblocked at both hydroxyl ends, which is usually preferably used as component (A), and the crosslinking is also cured. It is necessary to contain more amide groups or aminoxy groups. This is because if the average number of particles is less than 2, a sufficient cured film cannot be formed on the surface. Of course, the present invention also includes the case where a curing agent containing 3 or 4 or more amide groups or axonoxy groups in one molecule is used.

Usually, one containing two amide groups or aminoxy groups per molecule and one containing three or more amide groups or aminoxy groups per molecule are used in an appropriate mixture. There is no particular limitation on how the functional number of the amide group and the functional number of the aminoxy group are combined, but it is necessary to achieve low modulus and high elongation, or to improve storage stability when packaging. From the viewpoint of properties, etc., it is preferable to use the one with higher reaction activity among the two functional groups. in general.

Because amide group-containing organosilicon compounds have higher reactivity than aminoxy group-containing organosilicon compounds, for example, when using an amide group-containing organosilicon compound as a difunctional component, trifunctional or higher functional components are used. It is preferable to use an amide group-containing organosilicon compound or an aminochloro group-containing organosilicon compound as the difunctional component, and when using an aminoxy group-containing organosilicon compound as the difunctional component, an aminoxy group-containing component as the trifunctional or higher functional component. Preference is given to using organosilicon-containing compounds.

(8) If the amount of the component added is too small, the curing will be insufficient, and the storage stability when packaging it will be poor; if it is too large, the curing speed will be slow, which may be economically disadvantageous. Therefore, 0.5 to 30 parts by weight, preferably 1 to 20 parts by weight, per 100 parts by weight of organopolysiloxane as the prison component.
Parts by weight range.

1 The dialkoxysilane or its partially hydrolyzed condensate used in the present invention (O component) is an important component for imparting paintability to the silicone rubber surface of the composition after room temperature curing, which is the object of the present invention. If no component is added, paint is applied to the surface of the cured rubber-like elastic body.
Although it cannot be bonded, if 0 components are added, various paints can be applied and bonded extremely easily. Also.

(The reason why component 0 is limited to dialkoxysilane or its partially hydrolyzed condensate is 9. For example, when a trialkoxysilane compound is used, the coating properties of the paint are inferior to dialkoxysilane/.

Furthermore, the surface tackiness of the obtained cured composition was too high, and the fluidity of the uncured composition was too high, resulting in poor workability. This is because even if a certain composition is used, the strength of the silicone rubber changes greatly after curing, making it difficult to control.

(Component Q is a dialkoxysilane or a partially hydrolyzed condensate thereof represented by the general formula R2 It is a monovalent group selected from the group consisting of Organic groups, including methylene and ethylene groups.

Propylene group, butylene group, chlorethylene group.

Fluoroethylene group, 7-enylene group.

-CH2OCH2CH, 4H2- group, -CH2cH2
OcH2CH, group.

CH3 ■ -CH2OCHCH2- group, -cH20CHgCH2
0C Kushima-moto.

Examples include divalent organic groups consisting of a combination of two or more of these groups. R2 and R3 are substituted or unsubstituted monovalent hydrocarbon groups, and include methyl, ethyl, Propyl group, octyl group, phenyl group, vinyl group,
Examples include 13.3-17 fluoroprobyl group.

As R3, an alkyl group or an alkoxyalkyl group is particularly preferred.

Such dialkoxysilane compounds include Strain 1, for example, γ-mercaptopropyl methyldimethoxysilane,
δ-mercaptobutyl methyldimethoxysilane, γ-
Mercapto group-containing dialkoxysilane such as mercaptobutyl methyljethoxysilane, r-aminopropyl methyldimethoxysilane, r-aminopropyl methyljethoxysilane, r-(β-aminoethylamino)
Dialkoxysilanes containing amino groups such as propyl/methyldimethoxysilane.

r-acryloxyglopyl methyldimethoxysilane,
γ-acryloxyglobil methyldimethoxysilane,
Acryloxy group-containing dialkoxysilane such as r-methacryloxypropyl methyldimethoxysilane, γ-glycidyloxyglobil methyldimethoxysilane, β
-(3,4-epoxycyclohexyl)ethyl methyldimethoxysilane and other epoxy group-containing dialkoxysilanes and partially hydrolyzed condensates of these dialkoxysilanes are exemplified.

The amount of 0 component added is 0.0 per 100 parts by weight of the prisoner component.
It is in the range of 5 to 15 parts by weight, preferably in the range of 0.1 to 5 parts by weight. If the amount added is too small, the coating properties of the paint will be insufficient for practical use.

This is because if the amount added is too large, it will be economically disadvantageous.

In addition to the ingredients, the composition of the present invention further contains a finely powdered inorganic filler in order to improve the flow characteristics before curing and to impart the necessary mechanical properties as a sealant after curing. It is preferable to add. The amount added is 10
5 to 500 parts by weight, preferably 20 to 0 parts by weight
The range is 300 parts by weight. Examples of inorganic fillers include fumed silica, pyrogenic silica, precipitated silica, fine quartz powder,
Examples include calcium carbonate, titanium oxide, diatomaceous earth, aluminum hydroxide, alumina, and those surface-treated with silanes, silazane, low polymerization degree siloxanes, organic compounds, etc. When used as a building sealant, especially when low modulus and high elongation are required, calcium carbonate is preferably used. Furthermore, the composition of the present invention includes an organic solvent, a fungicide, a flame retardant, a plasticizer,
A thixotropic agent, an adhesion promoter, etc. can be added.

Unlike conventional silicone sealants, the composition of the present invention can be coated and bonded with various paints after it hardens into a rubber-like elastic body, and there is no need to apply paint after applying the sealant. It can be suitably used for sealing joints around the exterior walls of certain buildings, adhering specially colored members (no need to color the sealant), etc.

The present invention will be explained below with reference to nine examples. In the Examples, 1 part indicates a part by weight. In addition, the following abbreviations were used in the examples.

M2O: 50% tensile stress, T: maximum tensile stress.

E1□: Elongation at maximum load.

In addition, [Applicability Lath] J and "Adhesion Test" in Examples were conducted according to the following methods.

[Spreadability test]

The present composition and the composition of the comparative example were cured into a sheet-like elastic body with a thickness of 2.5 mm, and paint was applied (one coat with a brush) to 51 square areas of the surface, and the paint repellency was measured. Judging by the situation. If it can be applied evenly, it is ○, and if it can be applied to 50 to 90% of the entire area, it is Δ.

If it is less than 40%, mark it as ×.

[Adhesiveness Test] After conducting the applicability test, if the paint is repellent, apply 2 to 3 coats to cover the entire surface as much as possible. After confirming by smell that the paint was sufficiently cured, an 18-part wide strip of Seronone Tape was pasted onto the paint and peeled off to check for peeling of the paint film. Q when the coating and cured sheet adhere well, × when it peels off almost without resistance.
Anything in between is marked △.

Example 1 α with a viscosity of 6000 centipoise at 25°C.

100 parts of ω-dihydroxy-dimethylpolysiloxane, 30 parts of light calcium carbonate, 4 parts of light calcium carbonate
0 parts were added and mixed until uniform. to 100 parts of this pace mixture.

part, and 0 component TeH8(CH2)3-8t (O
1 part and 2 parts of CH3)21CH3 were added and mixed until uniform. A 2.5 part thick sheet was prepared using this composition and allowed to stand at room temperature for one week to cure into a rubber-like elastomer. A spreadability test and an adhesion test were conducted on this product. Also.

Using the same composition, an H-type seal indica defined in JIS-A7558 (adherent glass, Primer D manufactured by Toray Silicone Co., Ltd. was used) was prepared.

After being left at room temperature for two weeks, a tensile test was conducted.

On the other hand, as a comparative example, from the above composition, 0 components were used.
(CHz)a 5i(OCHa)z (Composition CH3 excluding D
Create a + sheet and HW Ji Invasion.

Spreadability test, adhesion test and tensile test The results are shown in Table 1.

Table 1 1) Synthetic resin emulsion paint (manufactured by Kansai Paint Co., Ltd., Vini Deluxe 300) 2) Synthetic resin formulation/paint (manufactured by Nippon Paint Co., Ltd., CR Paint) 3) Acrylic resin paint (manufactured by Kansai Paint Co., Ltd., AP Paint) Example 2 H8(CH2)3-S i (OCH3)2CH used in Example 1 or as a component.

A composition similar to Example 1 was prepared, except that the organosilicon compounds shown in Table 2 were used instead of.

A test similar to that in Example 1 was conducted. The results are shown in Table 1. For convenience, the comparative example used in Example 1 is also listed.

Example 3 α with a viscosity of 9000 centivoids at 25°C.

40 parts of light calcium carbonate and heavy calcium carbonate were uniformly mixed with 100 parts of ω-dihydroxy-dimethylpolysiloxane. to 100 parts of this base mixture.

A uniformly mixed composition was prepared using the organic silicon compounds shown in Table 3 as the and Ω components.

A test similar to that in Example 1 was conducted using this composition. In addition, as a comparative example, a composition in which only the Ω component was not added was also used.

The same procedure was carried out. The results of these tests are shown in Table 3.

Example 4 α with a viscosity of 12,000 centivoise at 25'0.

100 parts of ω-dihydroxy-dimethylpolysiloxane,
Parts of light calcium carbonate and 70 parts of heavy calcium carbonate were mixed until uniform. 4 parts dimethylbis(N-ethylacetamido)silane to 100 parts of this base mixture.

and 1 part of CH3 bone l5 (CH2) 381 (OCHs) 2 were added and mixed until homogeneous. An elastomer sheet of 2.5 parts thick made using this composition was subjected to a spreadability test and an adhesion test.

Paint A, paint B and paint C (same as above) could be applied and adhered well.

Claims (1)

[Claims] (A) Viscosity at 25°C is 20 to 1,000,0
100 parts by weight of organopolysiloxane with 00 centivoids and one molecular chain end blocked with a hydroxyl group)
Two or more amide groups and/or as functional groups in one molecule
or an organosilicon compound having an aminoxy group
05 to 30 parts by weight (wherein, or a dialkoxysilane represented by 0) representing an unsubstituted monovalent hydrocarbon group or a partially hydrolyzed condensate thereof o, o
An organopolysiloxane composition which can be coated after being cured at room temperature, comprising s to 15 parts by weight.