JP2002194217A - Room temperature curable polyorganosiloxane composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a room-temperature-curable polyorganosiloxane composition having excellent adhesion to an acrylic resin. SOLUTION: (A) 100 parts by weight of a polyorganosiloxane substantially represented by the following general formula: and (B) organosilane represented by the following general formula: and / or partial hydrolysis thereof 1 to 30 parts by weight of condensate, (C) 12 to 50 parts by weight of finely divided silica, (D) 0.01 to 10 parts by weight of a curing catalyst, and (E) general formula: (X) ₃ Si (CH ₂ ) _n S
0.01 to 15 parts by weight of mercaptosilane represented by H,
At a predetermined ratio.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a one-component room-temperature-curable polyorganosiloxane composition which cures at room temperature with moisture in the air, and more particularly to an improved adhesiveness to an acrylic resin. The present invention relates to a room temperature-curable polyorganosiloxane composition.

[0002]

2. Description of the Related Art Conventionally, a so-called condensation reaction type liquid silicone rubber composition which is cured at room temperature by moisture in the air to become a rubber elastic body is well known, and is well known in various fields such as construction, machinery and electricity. Widely used as sealing materials, industrial adhesives, potting materials, molding agents, and the like.

[0003] However, such a room-temperature-curable polyorganosiloxane composition has a drawback that it has poor adhesion to various substrates such as glass, metal, and plastic. Therefore, various proposals have been made to overcome this disadvantage.

For example, Japanese Patent Application Laid-Open No. 1-306469 discloses a room-temperature curability in which an organopolysiloxane and an organosilane are mixed with a mercapto group-containing alkoxysilane and a curing catalyst to improve adhesion to metals and glass. An organopolysiloxane composition is disclosed.

[0005]

However, although the room-temperature-curable organopolysiloxane composition has improved adhesion to copper, glass and epoxy resins, it has insufficient adhesion to aluminum and polycarbonate resins. With respect to the adhesiveness to an acrylic resin, the adhesiveness was hardly improved, and there was a problem that a room-temperature-curable organopolysiloxane composition having sufficient adhesiveness to an acrylic resin had not yet been obtained.

[0006] The present invention has been made in view of the above-mentioned conventional problems. That is, an object of the present invention is to provide a room temperature-curable polyorganosiloxane composition having excellent adhesion to an acrylic resin.

[0007]

Means for Solving the Problems The present inventors have made intensive studies to achieve such an object, and as a result, when formulating a basic component of a specific room temperature-curable polyorganosiloxane composition, a specific The inventors have found that a composition having excellent adhesion to an acrylic resin can be obtained by blending mercaptosilane and, if necessary, specific aminosilane and epoxysilane, and have completed the present invention.

That is, the one-component room temperature-curable polyorganosiloxane composition for a sealing material of the present invention basically comprises (A) a compound represented by the general formula:

Embedded image (Wherein, R represents a substituted or unsubstituted monovalent hydrocarbon group, and n is a positive integer), and 100 parts by weight of a polyorganosiloxane having a viscosity at 25 ° C. of 100 to 500,000 cP. Part, (B) general formula:

Embedded image (Wherein R1 represents a substituted or unsubstituted monovalent hydrocarbon group,
R2 represents the same or different monovalent hydrocarbon groups, and m is 0, 1 or 2), and 1 to 30 parts by weight of an organosilane represented by the following formula:
(C) fine powder silica 12 to 50 parts by weight, (D) curing catalyst
0.01 to 10 parts by weight, and (E) a general formula: (X) ₃ Si (CH ₂ ) _n SH (wherein X represents R or RO, and R represents a methyl group, an ethyl group, a propyl group, a vinyl group, Or a phenyl group, and n represents an integer of 1 to 3.) 0.01 to 15 parts by weight of mercaptosilane.

The polyorganosiloxane of the component (A) in the present invention serves as a base polymer of the composition obtained according to the present invention, and has been conventionally used as a base of a condensation reaction type liquid polymer.

Therefore, it is necessary that at least two hydroxyl groups bonded to a silicon atom be contained in one molecule, and since the cured composition has good mechanical properties, the silicon atom bonded to the hydroxyl group must be contained. Is at the end of the polyorganosiloxane, that is, the general formula:

Embedded image (Wherein, R represents a substituted or unsubstituted monovalent hydrocarbon group, and n is a positive integer).

The organic group R bonded to the silicon atom of the polyorganosiloxane is a monovalent hydrocarbon group such as a methyl group, an ethyl group, a propyl group, a butyl group, a vinyl group, a phenyl group, a chloromethyl group, a cyanoethyl group. , 3,3,3-
A monovalent substituted hydrocarbon group such as a trifluoropropyl group is exemplified. It is preferable that 85% or more of R is a methyl group because it has an appropriate curing rate, the fluidity before curing is easy to handle for application, and the physical properties after curing, especially the modulus is low. It is best for all of R to be a methyl group from the viewpoint of easiness, but when heat resistance, cold resistance and the like are particularly required, it is better to use a phenyl group as a part of R.

The range of n also depends on the type of R and its molar ratio, but it is easy to handle, the fluidity of the composition,
Due to the physical properties after curing, the viscosity of component (A) is 100c at 25 ° C.
It is selected to be P to 500,000 cP, and when R is all methyl groups, it corresponds to n being in the range of approximately 20 to 3000.

If the viscosity of the component (A) is less than 100 cP, it is difficult to obtain good physical properties due to low viscosity,
Exceeding cP tends to deteriorate extrusion workability and curability.

The component (B) used in the present invention comprises (A)
A cross-linking agent for cross-linking the components to give a network structure,
For that purpose, an organosilane containing at least two ketoxime groups bonded to a silicon atom in one molecule or a partially hydrolyzed condensate thereof is used.

The organosilane having a ketoxime group is specifically represented by the following general formula:

Embedded image (Wherein R1 represents a substituted or unsubstituted monovalent hydrocarbon group,
R2 represents the same or different monovalent hydrocarbon groups, and m is 0, 1 or 2).

Examples of the organic group R1 other than the ketoxime group bonded to the silicon atom include monovalent hydrocarbon groups such as methyl group, ethyl group, propyl group, butyl group, vinyl group and phenyl group, chloromethyl group, Cyanoethyl group, 3,3,3
Examples thereof include a monovalent substituted hydrocarbon group such as a trifluoropropyl group, which is preferably a methyl group, a phenyl group or a vinyl group because it gives an appropriate curing rate.

Examples of such an organosilane include silane compounds such as methyltris (diethylketoxime) silane, methyltris (methylethylketoxime) silane, vinyltris (methylethylketoxime) silane and phenyltris (diethylketoxime) silane.
Alternatively, these partially hydrolyzed condensates are exemplified.

The component (B) is used in an amount of 1 to 30 parts by weight based on 100 parts by weight of the component (A). If the amount of the component (B) is less than 1 part by weight, a cured product having excellent elasticity and mechanical properties cannot be obtained, and if it exceeds 30 parts by weight, the obtained cured product becomes brittle.

The finely divided silica of the component (C) used in the present invention is a reinforcing filler that imparts mechanical strength to the cured rubber elastic body. As such a reinforcing filler,
Examples thereof include fumed silica, calcined silica, precipitated silica, and those obtained by hydrophobizing the surfaces thereof with organochlorosilanes, polyorganosiloxanes, hexamethyldisilazane, and the like.

The component (C) is used in an amount of 1 to 50 parts by weight, preferably 5 to 25 parts by weight, based on 100 parts by weight of the component (A). In particular, it is desirable to use it in the range of 12 to 50 parts by weight.

If the amount of the component (C) is less than 1 part by weight, sufficient mechanical strength cannot be obtained and dripping cannot be sufficiently prevented. On the other hand, if it exceeds 50 parts by weight, mixing becomes difficult, and the compound becomes too hard, so that, for example, proper viscosity as a sealing material cannot be obtained.

The curing catalyst of the component (D) used in the present invention promotes the condensation reaction between the components (A) and (B). Examples of such a curing catalyst include iron octoate, cobalt octoate, manganese octoate, zinc octoate, tin naphthenate, tin caprylate, and carboxylic acid metal salts such as tin oleate; dibutyltin diacetate, dibutyltin dioctoate, dibutyltin dilaurate, Dibutyltin oleate, diphenyltin diacetate, dibutyltin oxide,
Organotin compounds such as dibutyltin dimethoxide, dibutylbis (triethoxysiloxy) tin, dioctyltin dilaurate; tetrabutyl titanate, tetra-
Examples thereof include organic titanates such as 2-ethylhexyl titanate, triethanolamine titanate, and tetra (isopropenyloxy) titanate; organic titanium compounds such as organosiloxytitanium and β-carbonyltitanium; and alkoxyaluminum compounds.

The component (D) is used in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the component (A). If the compounding amount of the curing catalyst exceeds 10 parts by weight, not only the curability becomes fast, but also the mechanical properties of the sealing material after curing are adversely affected.

The mercaptosilane (E) used in the present invention is an important component for imparting adhesiveness to an acrylic resin. The mercaptosilane is specifically represented by the general formula: (X) ₃ Si (CH ₂ ) _n SH ( _where X represents R or RO, and R represents a methyl group, an ethyl group, a propyl group, a vinyl group, or Represents a phenyl group, and n represents an integer of 1 to 3).

Examples of such mercaptosilane include H
S (CH ₂ ) Si (OCH ₃ ) ₃ , that is, 3-mercaptopropyltrimethoxysilane or HS (CH ₂ ) Si
_{(OCH 3)} 3, i.e. 3-mercaptopropyl triethoxysilane are exemplified. Particularly, 3-mercaptopropyltrimethoxysilane is preferable.

The component (E) is preferably used in an amount of 0.01 to 15 parts by weight, more preferably 0.05 to 10 parts by weight, based on 100 parts by weight of the component (A). Is more preferred.

If the amount of the component (E) is too small, sufficient adhesiveness to the acrylic resin cannot be obtained. If the amount is too large, the effect of improving the adhesiveness to the acrylic resin is saturated, which is economically disadvantageous. It is because it becomes.

The composition of the present invention comprises the above (A) to
Each component of (E) is used as a basic component, and if necessary, other known fillers, plasticizers, coloring agents, heat resistance improvers, flame retardants, fungicides, adhesion promoters, etc. are used in the present invention. You may mix | blend in the range which does not impair the effect of.

If necessary, aminosilane and / or epoxysilane may be added.

These amino silanes and epoxy silanes are components that further improve the adhesiveness with the acrylic resin.

These aminosilanes and epoxysilanes are preferably added as a heated mixture.

Examples of the aminosilane include N- (2-aminoethyl) -3-aminopropyltrimethoxysilane and N- (2-aminoethyl) -3-aminopropyltriethoxysilane. Particularly, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane is preferable.

Examples of the epoxy silane include 3-glycidoxypropyltrimethoxysilane and 3-glycidoxypropyltriethoxysilane. Particularly, 3-glycidoxypropyltrimethoxysilane is preferred.

These aminosilanes, epoxysilanes,
Alternatively, as a heated mixture of aminosilane and epoxysilane, 0.01 parts by weight of the above component (A)
It is preferably used in the range of from 15 to 15 parts by weight,
More preferably, it is used in the range of 10 to 10 parts by weight.

If the amount of the aminosilane, the epoxysilane, or the heated mixture of the aminosilane and the epoxysilane is too small, sufficient adhesion to the acrylic resin cannot be obtained. If the amount is too large, the adhesion to the acrylic resin is improved. This is because the effect is saturated and economically disadvantageous.

In the present invention, when the essential components (A) to (E) and the optional components described above are blended and mixed, first, a polyorganosiloxane of component (A), which is a base polymer, and a crosslinking agent. The component (B), organosilane and / or its partially hydrolyzed condensate, is blended in advance with a mixer, kneader, or the like at the above-mentioned mixing ratio, and mixed so as to be uniform. This mixing is performed in a state where the moisture is turned off.

Next, the mixture is mixed with a fine filler silica (C) as a reinforcing filler and a curing catalyst (D),
(E) The component mercaptosilane and, if necessary, the above-mentioned optional components are blended in the same manner as described above,
Mix until uniform.

The mixture of the component (A) and the component (B) is blended again with the fine powder silica of the component (C) and then for the purpose of further adjusting the viscosity of the system. You may.

By mixing the components (A) and (B) in advance in this way, a room-temperature-curable polyorganosiloxane composition having an appropriate viscosity even before curing and having drastically improved dripping properties. Things are obtained.

Further, the addition of mercaptosilane significantly improves the adhesiveness to the acrylic resin.

According to the room-temperature-curable polyorganosiloxane composition of the present invention, a room-temperature-curable polyorganosiloxane composition having excellent adhesion to an acrylic resin can be obtained by blending mercaptosilane.

Therefore, the room-temperature-curable polyorganosiloxane composition obtained by the production method of the present invention has excellent adhesiveness to acrylic resins when used as various sealing materials such as sealing materials for buildings. As shown, the range of materials to be applied is widened and very effective.

[0043]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to embodiments. In addition, all the parts in the following Examples and Comparative Examples indicate parts by weight. Also,
Unless otherwise stated, characteristic values such as viscosity indicate values measured at 25 ° C.

(Examples 1 to 4) First, both ends of a molecular chain as a base polymer were blocked with hydroxyl groups and the viscosity was 100%.
100 mP · s of polydimethylsiloxane 100 parts, vinyl tris (methyl ethyl ketoxime) as a crosslinking agent
6.8 parts of silane, Aerosil 20 as finely divided silica
No. 0 (trade name, manufactured by Nippon Aerosil Co., Ltd.) was treated with a hexamethyldisilazane surface-treated powder (12 parts) and dibutyltin dilaurate (0.07 part) as a curing catalyst was used as a basic composition. For a typical formulation, 3-mercaptopropyltrimethoxysilane as mercaptosilane and N- (2-
Aminoethyl) -3-aminopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane as epoxysilane, the above-mentioned aminosilane (N- (2-aminoethyl) -3-aminopropyltrimethoxysilane) and epoxysilane ( A heated mixture with 3-glycidoxypropyltrimethoxysilane) was blended in the proportions shown in Table 1, and these were charged into a moisture-proof mixer, mixed in this state, and mixed with Samples 1 to 4 (Examples 1 to 4). 4) was produced.

Next, the adhesion of these room-temperature-curable polyorganosiloxane compositions to various substrates was measured.

The results of these measurements are as shown in Table 1. Here, the adhesion test method is the same as the tab adhesion test method, and the room-temperature-curable polyorganosiloxane composition is bead-shaped (15 mm wide × 40 mm long ×
Extruded to a thickness of 5 cm) at a temperature of 20 ° C and a humidity of 55
% For 7 days to cure. Next, the obtained bead-shaped cured product was pulled, peeled off from the substrate surface, the peeled surface was observed, and the rate of breakage in the cured product layer was expressed as the cohesive failure rate%.

For comparison, the results of measuring the adhesion of the room-temperature-curable polyorganosiloxane composition obtained in the same manner as described above except that no mercaptosilane was used are also shown in Table 1.

[0048]

[Table 1] As described above, from the results of Examples 1 to 4 and Comparative Examples 1 to 4 shown in Table 1, in mixing the components (A) to (D) of the present invention, 3-mercaptopropyl was used as the component (E). It was confirmed that when a mercaptosilane such as trimethoxysilane was used in combination, an excellent effect of significantly improving the adhesiveness to an acrylic resin was obtained.

Further, in addition to the mercaptosilane as the component (E), an aminosilane such as N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, or an epoxy such as 3-glycidoxypropyltrimethoxysilane It was confirmed that when silane or the above-mentioned heated mixture of aminosilane and epoxysilane was used in combination, the adhesion to the acrylic resin was further improved.

On the other hand, the components (A) to (D) of the present invention
In mixing the components, when the mercaptosilane of the component (E) is not added and only aminosilane, epoxysilane, or a heated mixture of these aminosilanes and epoxysilane is added, the adhesion to the acrylic resin is not improved. Was confirmed.

As is clear from the results of each of the above Examples and Comparative Examples, the room-temperature-curable polyorganosiloxane composition of the present invention has remarkably improved adhesiveness to an acrylic resin, and has various sealing materials and adhesives. It is very effective as an agent.

[0052]

According to the room-temperature-curable polyorganosiloxane composition of the present invention, a room-temperature-curable polyorganosiloxane composition having excellent adhesion to an acrylic resin can be obtained by blending mercaptosilane.

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Claims (6)

[Claims] 1. Basically (A) a general formula: (Wherein, R represents a substituted or unsubstituted monovalent hydrocarbon group, and n is a positive integer), and 100 parts by weight of a polyorganosiloxane having a viscosity at 25 ° C. of 100 to 500,000 cP. Part, (B) general formula: (Wherein R1 represents a substituted or unsubstituted monovalent hydrocarbon group,
R2 represents the same or different monovalent hydrocarbon groups, and m is 0, 1 or 2), and 1 to 30 parts by weight of an organosilane represented by the following formula:
(C) fine powder silica 12 to 50 parts by weight, (D) curing catalyst
0.01 to 10 parts by weight, and (E) a general formula: (X) ₃ Si (CH ₂ ) _n SH ( _where X represents R or RO, and R represents a methyl group, an ethyl group, a propyl group, or a vinyl group) Or a phenyl group, and n represents an integer of 1 to 3.) 0.01 to 15 parts by weight of a mercaptosilane represented by the following formula: 2. The room-temperature-curable polyorganosiloxane composition according to claim 1, further comprising 0.01 to 15 parts by weight of aminosilane and / or epoxysilane. Organosiloxane composition. 3. The room-temperature-curable polyorganosiloxane composition according to claim 1, wherein the finely divided silica as the component (C) is untreated silica. Polyorganosiloxane composition. 4. The room temperature-curable polyorganosiloxane composition according to claim 1, wherein the finely divided silica as the component (C) is a silica surface-treated with hexamethyldisilazane. Room temperature-curable polyorganosiloxane composition. 5. Basically (A) a general formula: (Wherein, R represents a substituted or unsubstituted monovalent hydrocarbon group, and n is a positive integer), and 100 parts by weight of a polyorganosiloxane having a viscosity at 25 ° C. of 100 to 500,000 cP. Part, (B) general formula: (Wherein R1 represents a substituted or unsubstituted monovalent hydrocarbon group,
R2 represents the same or different monovalent hydrocarbon groups, and m is 0, 1 or 2), and 1 to 30 parts by weight of an organosilane represented by the following formula:
(C) 1 to 50 parts by weight of finely divided silica whose surface has been hydrophobized, (D) 0.01 to 10 parts by weight of a curing catalyst, and (E)
General formula: (X) ₃ Si (CH ₂ ) _n SH ( _where X represents R or RO, R represents a methyl group, an ethyl group, a propyl group, a vinyl group, or a phenyl group; At room temperature curable polyorganosiloxane composition comprising 0.01 to 15 parts by weight of a mercaptosilane represented by an integer of 3). 6. The room temperature-curable polyorganosiloxane composition according to claim 5, wherein the finely divided silica as the component (C) is a silica surface-treated with hexamethyldisilazane. Room temperature curable polyorganosiloxane composition.