JPH0616967A - Primer composition - Google Patents

Abstract

PURPOSE:To provide a primer composition containing a poly(silalkylenesiloxane) having a specific structure, useful for bonding various sealing materials, etc., to an adherend and capable of keeping high adhesiveness over a long period under alkaline or acidic condition. CONSTITUTION:The composition contains a poly(silalkylenesiloxane containing a silicon functional group and having a molecular skeleton alternately containing silalkylene bonds and disiloxane bonds. The poly(silalkylenesiloxane) can be produced by hydrolyzing a disilalkylene containing hydrolyzable group such a dichlorotetramethylenedisilmethylene. The disilalkylene containing hydrolyzable group is obtained as a by-product of a direct synthesis process of methylchlorosilanes. The above composition is preferably compounded with 0.1-20wt.% of a catalyst such as tin octylate to attain high adhesiveness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a primer composition, and more particularly to a primer composition for improving the adhesiveness and durability between a condensation type room temperature curable silicone elastomer and various adherends under acidic or alkaline conditions. Regarding things.

[0002]

2. Description of the Related Art Condensation type room temperature curable silicone elastomer compositions, silicon alkoxide type coating compositions, silylated polyether type and polysulfide type materials are used as sealing materials for joints of buildings or coating materials for building outer walls. Sealing materials such as polyurethane are widely used. In order to strongly adhere these compositions to a substrate, it is widely practiced to apply various kinds of primers on the surface of the substrate. Such a primer is mainly composed of various silanes or their co-hydrolysates.

However, these primers form a thin layer composed of a siloxane skeleton having a high ionic bond property in order to impart adhesiveness between the sealing material and the base material, and therefore they have acid resistance and alkali resistance. Not enough. Therefore, after the construction, while curing and functioning as an adhesive layer, due to the acid rain that has recently occurred, or in the area around the factory, especially in areas with high acidity or alkalinity in the atmosphere, due to its influence, as a primer There is a problem that the adhesiveness cannot be maintained and the durability is low. In particular, in the case of silicone elastomer, although the durability of the elastomer itself is excellent, there is a problem that the primer layer is destroyed because the durability of only the primer layer at the interface where liquid or vapor easily penetrates is low. .

On the other hand, conventional alkaline primers such as mortar, concrete, lightweight foamed concrete, etc. have the problems that they are deteriorated quickly and the durability of adhesion is low.

[0005]

The present invention improves the adhesiveness and durability of various sealing materials such as condensation type room temperature curable silicone elastomers and coating materials to various adherends under acidic or alkaline conditions. An object of the present invention is to provide a primer composition for achieving the above.

[0006]

Means for Solving the Problems As a result of earnest studies to achieve these objects, the present inventor has found that a primer composition containing a poly (silalkylene siloxane) having a specific molecular structure The inventors have found that the adhesiveness can be remarkably maintained even under acidic or alkaline conditions, and have completed the present invention.

That is, the present invention relates to a primer composition containing a poly (silalkylene siloxane). Here, the poly (silalkylene siloxane) is a polymer basically having a silalkylene bond and a disiloxane bond (Si-O-Si) alternately in the molecular skeleton, and a part of the trisiloxane chain (Si-O). −
Si-O-Si) may be formed. Those having a longer siloxane chain cannot obtain sufficient acid resistance and alkali resistance suitable for the acid / alkali resistance primer which is the object of the present invention. The molecular skeleton may be linear, branched, cyclic or network. The average molecular weight is not particularly limited, but 700 to 30,000
Is preferred.

Examples of the alkylene group forming a silalkylene bond include methylene, ethylene, trimethylene, tetramethylene, pentamethylene, hexamethylene and a longer alkylene group. However, methylene and ethylene are preferred because of easy synthesis. preferable.

The poly (silalkylene siloxane) used in the present invention is particularly reactive with a sealing material or a base material in order to obtain adhesiveness and strength as a primer,
It has a silicon functional group attached to a silicon atom. The silicon functional group is preferably a silanol group; an alkoxy group such as methoxy, ethoxy, propoxy, isopropoxy, butoxy; an alkoxyalkoxy group such as a 2-methoxyethoxy group; an alkenyloxy group such as a propenoxy group; and an aminosilyl group, A silanol group, a methoxy group, and an ethoxy group are particularly preferable because of easy synthesis and reactivity.

Other substituents bonded to silicon include a substituted or unsubstituted monovalent hydrocarbon group and a hydrogen atom. For example, methyl, ethyl, propyl, butyl,
An alkyl group such as pentyl; a cycloalkyl group such as cyclohexyl; an aryl group such as phenyl and tolyl; an aralkyl group such as benzyl, 2-phenylethyl, 2-phenylpropyl; and one or more of these groups. In some cases, all hydrogen atoms may be replaced with halogen atoms such as fluorine, chlorine and bromine, and cyano groups.

Further, the poly (silalkylene siloxane) used in the present invention includes plastic, organic rubber,
Carbon functional groups may be included in the molecule to impart strong adhesion to special substrates such as surface treated aluminum. Examples of the organic group containing a carbon functional group and bonded to a silicon atom include glycidoxypropyl group, aminopropyl group, mercaptopropyl group, hydroxypropyl group, methacryloxypropyl group, ureidopropyl group and isocyanato group. Examples include propyl group and the like.

The poly (silalkylene siloxane) in the primer composition of the present invention can be represented, for example, by the following formula (blocks in parentheses do not mean blocks). The following abbreviations are used below. Me: methyl group Ph: phenyl group a, b, c: integer

[0013]

[Chemical 1]

[0014]

[Chemical 2]

[0015]

[Chemical 3]

In the poly (silalkylene siloxane) used in the present invention, the above poly (silalkylene siloxane) forms a siloxane bond by condensation of silicon functional groups present in the molecule, and the chain length is further extended. Alternatively, a polymer having a high molecular weight may be used. However, the shorter the siloxane chain introduced for chain length extension, the higher the acid resistance and alkali resistance of the resulting poly (silalkylene siloxane), and the easier availability of the silicon compound used for introducing the siloxane chain. Considering together, it is most preferable that the siloxane chain is a simple Si—O—Si bond.

The poly (silalkylene siloxane) as described above can be produced by any method. For example, poly (silalkylene siloxane) can be obtained by hydrolyzing disilalkylene having a hydrolyzable group by a known method. Diyl alkylene having a hydrolyzable group as a raw material can be produced by any method, one example of which is J. Organometal. Chem, 23, 6
3 (1970). It can also be obtained as a by-product of the direct synthesis method of methylchlorosilanes in the organosilicon industry. Examples of such organosilicon compounds include dichlorotetramethyldisylmethylene, trichlorotrimethyldisylmethylene, tetrachlorodimethyldisylmethylene, and their corresponding methoxy compounds and ethoxy compounds; dichlorotetramethyldisylethylene, trichlorotrimethyldimethyl Examples thereof include silethylene, tetrachlorodimethyldisylethylene, and their corresponding methoxy compounds and ethoxy compounds.

The silethylene bond is a silane having a hydrogen atom bonded to a silicon atom, such as methyldichlorosilane, dimethylchlorosilane, or a corresponding alkoxysilane, and a silane having a vinyl group bonded to a silicon atom, such as vinyltril. Chlorosilane, methylvinyldichlorosilane, dimethylvinylchlorosilane,
Alternatively, it can also be obtained by reacting with a corresponding alkoxysilane in the presence of a known hydrosilylation catalyst.

The method of hydrolytic condensation is to hydrolyze the organosilicon compound having each hydrolyzable group separately,
Subsequently, they may be condensed, or the respective organosilicon compounds may be mixed and hydrolyzed and condensed. Further, these organosilicon compounds may be dropped into water or water may be dropped into the organosilicon compound. If necessary, it is also possible to use an organic solvent such as toluene, xylene, cyclohexane, n-hexane or acetone.

Further, in order to obtain a polymer having a desired molecular weight, the silanol group may be further condensed by a known method. In such a case, a poly (silalkylene siloxane) containing a silanol group obtained by the above-mentioned method or the like, a metal soap such as iron, manganese, cobalt, or zinc; an alkoxy compound such as titanium or aluminum; a chelate compound; or water It is achieved by adding an alkaline substance such as sodium oxide, potassium hydroxide or cesium hydroxide as a catalyst.

It is also possible to increase the molecular weight by introducing a siloxane bond by a reaction with another silicon-functional compound. For example dimethyldichlorosilane,
Ethylmethyldichlorosilane, pentylmethyldichlorosilane, phenylmethyldichlorosilane, dimethyldibromosilane, methyltrichlorosilane, ethyltrichlorosilane, pentyltrichlorosilane, phenyltrichlorosilane, tetrachlorosilane and their corresponding methoxy compounds, ethoxy compounds and the like, The latter can be made to have a high molecular weight by reacting with the poly (silalkylene siloxane) having a silanol group obtained above. Although any synthetic method may be used, for example, in the case of chlorosilane, the reaction is fast when the reaction is performed in the presence of a tertiary amine. In the case of alkoxysilane, the quaternary ammonium salt accelerates the reaction.

The poly (silalkylene siloxane) having an alkoxy group may be produced by the same method as a general method for introducing an alkoxysilyl group into polydimethylsiloxane having a silanol group. For example, poly (silmethylene siloxane) having the above silanol groups
And a silicon compound having a plurality of alkoxy groups by dealcoholization condensation. Examples of such silicon compounds include tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, and dimethyldimethoxysilane.

The composition of the present invention accelerates the reaction of silanol groups and other hydrolyzable groups present in the composition,
In order to quickly develop film strength and strong adhesion to the base material, sealing material or coating material,
It is desirable to use a catalyst. Such curing catalysts include tin carboxylates such as tin octylate; organotin carboxylic acids such as dibutyltin diacetate, dibutyltin dioctoate, dibutyltin dilaurate and dibutyltin diphthalate; organotin oxides such as dibutyltin oxide or esters thereof. Reaction products with: titanic acid esters such as tetrabutyl titanate; titanium chelate compounds such as diisopropoxybis (acetylacetonato) titanium and isopropoxy (2-ethylhexanediolato) titanium. If the addition amount of these catalysts is less than 0.01% by weight of the primer composition, the effect may be insufficient, and 50% by weight
Not only is it economically disadvantageous if it becomes the above, but the curing rate becomes too slow and the workability decreases, or precipitation or bleeding occurs and the curing decreases, so the range of 0.01 to 50% by weight is preferable. More preferable range is 0.1 to 2
It is 0% by weight.

The primer of the present invention is characterized in that it contains poly (silalkylene siloxane) as a main component as described above. In addition, however, it also contains a primer component of this type of sealing material or coating material. It doesn't matter. Such components include tetramethoxysilane,
Alkyl silicates such as tetraethoxysilane and tetrapropoxysilane and / or partial condensates thereof, 3-glycidoxypropyltrimethoxysilane,
Carbon functional silanes such as 3,4-epoxycyclohexylethyltrimethoxysilane and 3-aminopropyltriethoxysilane can be mentioned. The content of such components is preferably 20% by weight or less, and more preferably 10% by weight or less, based on the total amount of poly (silalkylene siloxane) and these components.

The composition of the present invention may contain an organic solvent for facilitating the coating operation. Examples of these organic solvents include ester-based solvents such as ethyl acetate and butyl acetate; ketone-based solvents such as acetone and methyl ethyl ketone; aromatic hydrocarbon-based solvents such as toluene, xylene and benzene;
Examples thereof include aliphatic hydrocarbons such as hexane and ligroin; alcohols such as methanol, ethanol and isopropyl alcohol; ethers such as diethyl ether, tetrahydrofuran and dioxane.

In addition, to the composition of the present invention, coloring pigments such as titanium oxide, carbon black and iron oxide; additives such as antioxidants, ultraviolet absorbers and anti-sagging agents can be added.

When the primer composition of the present invention is used, the primer may be thinly applied to the cleaned surface of the adherend by an appropriate method such as brush coating. This coating amount may be an amount sufficient to form a thin film of this primer on the surface of the adherend. A large amount of application may rather hinder the adhesion of the silicone elastomer.

[0028]

The primer composition of the present invention has acid resistance
It has excellent alkali resistance and can strongly bond various sealing materials such as condensation type room temperature curable silicone elastomers and coating materials to various adherends.
Form an adhesive layer with excellent acid and alkali resistance. Therefore, the adhesive strength can be maintained for a long period of time even under acidic or alkaline conditions such as an acidic or alkaline atmosphere, a state of being exposed to acidic rain, or the surface of an alkaline substrate. Therefore, the primer composition of the present invention is extremely useful as a primer for building sealing materials and coating materials that are expected to be exposed to such conditions.

[0029]

EXAMPLES The present invention will be described below with reference to synthesis examples and examples. The scope of the invention is not limited by these examples. In addition, in an Example and a comparative example, a part shows a weight part.

Synthesis Example 1 A 200-liter flask equipped with a dropping funnel, a thermometer, and a condenser was charged with 1,200 ml of water and 300 ml of acetone.
From the dropping funnel, ClM dissolved in 900 ml of toluene
e ₂ SiCH ₂ SiMe ₂ Cl with 600g and _{(3.0mol) ClMe 2 SiCH 2 SiMeCl} 2 to 332 g (1.5
mol) was added dropwise over 1 hour. After completion of dropping, stirring was continued for 1 hour as it was, and liquid separation was carried out, followed by heating and washing twice with saturated aqueous sodium hydrogen carbonate and once with water, and drying with anhydrous sodium sulfate. Then, under reduced pressure (heating to 100 ° C at 2 Torr)
The low-boiling point component was removed with to obtain 650 g of a colorless transparent liquid.
The obtained liquid had a HCl content of 0.1 ppm, which indicated that the raw material chlorosylmethylene was completely hydrolyzed. The distillate was mostly toluene,
Distilled below ℃ / 2 Torr, after that, 100 ℃
Even if it was heated up to almost no distillation was seen,
Since the yield is 97%, the raw material silmethylene is
It was found to be almost completely incorporated as product.

The obtained liquid had a viscosity of 130 cP (25
° C.), the refractive index (n _D 25): 1.45, specific gravity (25 ° C.):
It was 0.989 and silanol equivalent: 0.0037 mol / g. ^{When 1} H-NMR (CCl ₄ ) was measured, δ
= The signal attributable to Si-CH ₂ -Si in -0.12~-0.06ppm, δ = intensity ratio between the signal attributable to the Si-Me of -0.05~0.04ppm 1: 5. 5
Met. As a result of infrared spectroscopic analysis, the following absorptions were characteristic. ^{3100~3750cm -1 (SiOH) 1260cm -1 (} Si-Me) 1000~1100cm -1 (Si-O-Si, Si-CH 2 -
Si) GPC (chloroform) was measured to obtain a single peak, and the polystyrene-equivalent weight average molecular weight was 1,350.
Met. The exact structure of the molecular chain in the polymer molecule and the position of the silanol group cannot be specified, but from the above,
For example, the following poly (silalkylene siloxane)
Was determined to have been obtained.

[0032]

[Chemical 4]

Synthesis Example 2 In a 300 ml flask equipped with a cooling tube, 135 g of poly (silmethylenesiloxane) synthesized in Synthesis Example 1, 18.5 g (0.10 mol) of pentylmethyldichlorosilane and 15.8 g (0.10 mol) of pyridine were prepared. 20 mol) and charged at 80 ℃
The mixture was heated and stirred for 5 hours. The salt formed is filtered off and the temperature is 50 ° C.
When the low boiling point was distilled off under the condition of / 2 Torr, 146 g of a pale yellow transparent liquid was obtained. ^{When 1} H-NMR (CCl ₄ ) was measured, a signal was newly observed between 0 and 1 ppm as compared with the product of Synthesis Example 1, and introduction of a pentyl group could be confirmed. The viscosity was 123 cP, and the polystyrene-equivalent weight average molecular weight by GPC (chloroform) increased to 2,300.

Synthesis Example 3 68 g of poly (silmethylene siloxane) synthesized in Synthesis Example 1 was placed in a 200 ml flask equipped with a condenser and a thermometer.
76 g (0.50 mol) of tetramethoxysilane, 0.073 g (1.0 mmol) of diethylamine and 0.
A mixture of 060 g (1.0 mmol) was charged, and the mixture was heated and stirred at 80 ° C. for 8 hours. Remove the generated salt by filtration,
When the low boiling point was distilled off under the condition of 50 ° C / 2 Torr, 89 g
A pale yellow transparent liquid was obtained. ¹ H-NMR (CCl
₄ ), a new methoxy group signal is about 3.5.
Observed at ppm (signal ratio is as follows:-
0.12--0.06ppm: -0.05-0.04ppm
: 3.5 ppm = 1: 5.5: 2). The viscosity was 95 cP, and the polystyrene-equivalent weight average molecular weight by GPC (chloroform) was increased to 1,900.

Synthesis Example 4 In a 300 ml flask equipped with a water diverter, 100 g of poly (silmethylenesiloxane) synthesized in Example 1, 30 g of anhydrous xylene, Nikka Octix Zinc (metal content 8) manufactured by Nippon Kagaku Sangyo Co., Ltd. % Content) (1.0 g), and the mixture was heated with stirring at 140 ° C. for 3 hours. Along with the distilling of xylene into the water divider, some distilling of water was also observed. After removing xylene under reduced pressure, 98 g of a yellow liquid was obtained. The NMR and infrared spectroscopic charts of this product were exactly the same as those obtained in Example 1. Viscosity is 750cP (25 ℃), GP
The polystyrene-equivalent weight average molecular weight of C (chloroform) increased to 13,500.

Synthesis Example 5 70 ml of water was placed in a 200 ml eggplant-shaped flask, and 21.5 g (0.10 mol) of 1,1,4,4-tetramethyldichlorodisylethylene was added dropwise over 1 hour with vigorous stirring. Stirred at room temperature for 2 hours until the mixture separated cleanly. Hexane was added for liquid separation, followed by washing with water and drying with anhydrous sodium sulfate. When the solvent and the low boiling point compound were removed under reduced pressure (120 ° C./1 Torr), 6.2 g of a colorless transparent oily substance was obtained. 0 in ¹ H-NMR
One signal was observed around ppm. As a result of infrared spectroscopic analysis, absorption by Si-Me at 1,255 cm ^-1
1,050Cm ^-1 vicinity of Si-O-Si, Si- CH 2
-Si absorption was observed. The weight average molecular weight of polystyrene converted by GPC (chloroform) is 3,
It was 000.

The poly (silethylene siloxane) thus obtained was reacted with tetraethoxysilane in the same manner as in Synthesis Example 3. That is, in a 50 ml flask equipped with a cooling tube and a thermometer, 6.2 g (about 2.1 mmol) of the above poly (silethylenesiloxane), 6.0 g (40 mmol) of tetramethoxysilane, and diethylamine.
073 g (1.0 mmol) and acetic acid 0.060 g
(1.0 mmol) was charged and the mixture was heated at 80 ° C for 8 hours.
Heated and stirred. Generated salt is removed by filtration, 50 ℃ / 2
When the low boiling point was distilled off under the Torr condition, 6.4 g of a pale yellow transparent liquid was obtained. ^{In 1} H-NMR (CCl ₄ ), a new methoxy signal was observed at about 3.5 ppm (the signal ratio was about −0.1 to 0.1 ppm:
3.5 ppm = 15: 1). The polystyrene-equivalent weight average molecular weight by GPC (chloroform) was increased to 3,200.

Synthesis Example 6 (Synthesis of Comparative Example Sample) In a 300 ml flask, 100 g of poly (silmethylene siloxane) synthesized in Synthesis Example 1, 30 g (0.1 mol) of octamethylcyclotetrasiloxane and 0.
5 g was added and the mixture was heated with stirring at 90 ° C. for 4 hours. Then, the activated clay was removed by filtration, and unreacted octamethylcyclotetrasiloxane was distilled off under reduced pressure. As a result, 11
9 g of a pale yellow transparent liquid was obtained. ¹ H-NMR (C
In Cl ₄ ), the signal of the Si-Me group increased and the signal of the methylene proton of silmethylene was no longer observed separately. Viscosity is 125 cP, GPC
The polystyrene-equivalent weight average molecular weight of (chloroform) increased to 2,100.

Synthesis Example 7 (Synthesis of Comparative Sample) The silane was hydrolyzed in exactly the same manner as in Synthesis Example 1 except that 900 g of methyltrichlorosilane was used as the silicon compound. As a result, 420 g of a silicon compound was obtained. The polystyrene equivalent weight average molecular weight by GPC (chloroform) was 3,900.

Examples 1 to 5 and Comparative Examples 1 to 3 The polymers prepared in Synthetic Examples 1 to 7 were used to prepare 30 parts of polymer, 3 parts of tetraethoxysilane, 0.3 part of tetrabutyl titanate, 40 parts of toluene, and acetone. 30 parts were mixed to prepare primer compositions 1 to 7, respectively. Also, a primer composition 8 was prepared in which no polymer was added. These primer compositions were applied to a glass plate with a brush, left at 25 ° C. and 60% RH (hereinafter, these conditions are referred to as standard conditions) for 1 hour and dried, and then oxime type silicone sealant Tosseal 381
(Toshiba Silicone) was used to create an H-type test body. That is, in Examples 1 to 5, primer compositions 1 to 5 of the present invention, and in Comparative Examples 1 to 3, primer compositions 6 to 8
Was used.

This test body was aged under standard conditions for 14 days,
After further immersing in a 2% hydrochloric acid aqueous solution at 60 ° C. for 10 days, a tensile test was conducted to measure the fracture state, tensile stress and elongation. The results are summarized in Table 1.

[0042]

[Table 1]

Examples 6 to 10 and Comparative Examples 4 to 6 The primer compositions 1 to 8 used in Examples 1 to 5 and Comparative Examples 1 to 3 were applied to a mortar board with a brush,
After being left for one hour under standard conditions and dried, an H-type test body was prepared using Toxseal 381 (manufactured by Toshiba Silicone), an oxime-type silicone sealing material. That is, the primer compositions 1 to 5 of the present invention were used in Examples 6 to 10 and the primer compositions 6 to 8 were used in Comparative Examples 4 to 6.

This test body was aged under standard conditions for 14 days,
After further immersing in a 2% aqueous sodium hydroxide solution at 60 ° C. for 10 days, a tensile test was conducted to measure the fracture state, tensile stress and elongation. The results are summarized in Table 2.

[0045]

[Table 2]

As is clear from Tables 1 and 2, the primer according to the present invention maintained sufficient adhesiveness even after being dipped in a 2% aqueous solution of hydrochloric acid and sodium hydroxide.

Claims (2)

[Claims] 1. A poly (silalkylene siloxane) having a silicon functional group in the molecule, wherein the molecular skeleton has alternating silalkylene bonds and disiloxane bonds, although some may have trisiloxane bonds. A primer composition comprising: 2. The composition according to claim 1, wherein the silicon functional group is a silanol group, an alkoxy group or a silylamino group.