JPH0321577B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to a composition suitable as a sealant composition that can be cured at room temperature into a rubber-like elastic body when exposed to moisture, and in particular a rubber having excellent heat resistance and weather resistance and adhesive properties. The present invention relates to a room-temperature curable composition from which a shaped cured product is obtained. [Technical background of the invention and its problems] Polymers having hydrolyzable silicon functional groups and whose main chain is polyether are known (Japanese Patent Application Laid-Open No. 1983-1999).
156599, etc.). Room-temperature curable compositions based on this polymer have recently begun to be used as sealing materials for joints in buildings, joints in transportation machines, etc. (Japanese Unexamined Patent Publication No. 73998/1983, etc.). However, this type of polymer has poor heat resistance and weather resistance, so it can be used in joints of external walls of buildings where weather resistance is required.
There was a problem that it was not suitable for use in places where the temperature is relatively high, such as parts of the joints of transportation machines. Also,
This type of polymer does not inherently have adhesive properties, so for applications that require adhesive properties, it is necessary to prime the surface to be adhered before applying the sealant. There was a disadvantage. [Object of the Invention] The present invention is intended to solve these problems, and provides a room temperature curable composition from which a rubber-like cured product having excellent heat resistance and weather resistance and adhesiveness can be obtained. With the goal. [Structure of the Invention] That is, the present invention provides (A) (a) a polyether whose molecular chain terminals are blocked with an epoxy group, and (b) an aromatic ring or a heterocycle having two mercapto groups on the carbon atoms constituting the ring. A polyester whose molecular chain ends are blocked with a hydrolyzable silyl group obtained by reacting a bonded aromatic compound or heterocyclic compound and (c) an organosilicon compound having an epoxy group and a hydrolyzable group. The present invention relates to a room temperature curable composition characterized by comprising: 100 parts by weight of ether (B) 3 to 300 parts by weight of an inorganic filler (C) 0.001 to 20 parts by weight of a curing catalyst. (A) The polyether whose molecular chain terminal is blocked with an epoxy group has the general formula; (In the formula, R ¹ and R ² are divalent hydrocarbon groups, m is 10
Showing a number of ~500. ). In the above polyether, the oxyalkylene unit represented by R ¹ O is an oxyethylene unit,
Oxypropylene units or a combination system of oxyethylene units and oxypropylene units are preferred;
Oxypropylene units are particularly preferred because they are easy to obtain raw materials, easy to polymerize, and easily maintain a liquid state even at a high degree of polymerization. The degree of polymerization m of oxyalkylene units is 10~
Selected from a range of 500. When m is less than 10, it becomes difficult to obtain a rubber-like cured product with a viscosity that provides practical workability and a sufficient elongation rate. On the other hand, if m is larger than 500, the heat resistance and weather resistance, which are the characteristics of the present invention, will decrease. The divalent hydrocarbon group of R ² is a methylene group,
Uthylene group, trimethylene group, tetramethylene group, phenylene group, cyclohexylene group and

Examples include groups represented by [Formula]. Among these groups, a methylene group is preferred from the viewpoint of easy availability of raw materials. Typical examples of these components (a) include those obtained by condensing polyoxyethylene or polyoxypropylene, both ends of which are blocked with hydroxyl groups, with epichlorohydrin in the presence of a basic catalyst or the like. The compound (b) is a compound having two mercapto groups in the molecule that react with the epoxy groups of the components (a) and (c). For the purpose of obtaining heat resistance and weather resistance, which are the characteristics of the present invention, component (b) must be an aromatic compound or a heterocyclic compound, and the mercapto group must be an aromatic or heterocyclic compound. It is necessary that the compound be bonded to a carbon atom that constitutes the carbon atom.
These (b) components include 2,5-dimercapto, because of the ease of obtaining raw materials, ease of synthesis due to reactivity with epoxy groups and yield, and well-balanced physical properties of the obtained polymer. -1,
3,4-thiadiazole, dimercaptobenzene, dimercaptotoluene, dimercaptoxylene, dimercaptonaphthalene, etc. are recommended.
Among these, 2,5-dimercapto-1,3,
4-thiadiazole is particularly preferred for the above reasons. It goes without saying that in addition to these compounds having two mercapto groups, compounds having one or three or more mercapto groups can also be used in amounts that do not impede the object of the present invention. The organosilicon compound (c) has an epoxy group that reacts with the mercapto group (b), and further has a hydrolyzable group bonded to silicon. These (iii) components are preferably of the general formula;

[expression] or

〔Effect of the invention〕

The composition of the present invention has excellent heat resistance and weather resistance, has adhesive properties, and has no residual surface tackiness, so it exhibits excellent effects such as no staining due to adhesion of dust, and can be used for buildings. A room-temperature curable composition was obtained that is useful as a sealant for areas that require weather resistance, such as exterior wall joints, and areas that are exposed to relatively high temperatures, such as parts of transportation machine joints. [Example] The present invention will be explained below with reference to Examples. In addition, in the synthesis examples, examples, and comparative examples, all parts are parts by weight.
% refers to % by weight. Synthesis Example 1 For 5 moles [10 (epoxy) equivalents] of glycidyl group-end-blocked polyoxypropylene with an average degree of polymerization of 15, a molecular weight of approximately 1000, and a viscosity at 25°C of 270 cSt,

6 2,5-dimercapto-1,3,4-thiadiazole represented by [Formula]
Methanol in an amount equivalent to 10% of the mole and polyoxypropylene was added, and heating and stirring was started at 60° C. under a nitrogen atmosphere. A portion was taken out at 4 hour intervals from the start of heating and stirring, and the peak due to protons of epoxide methylene (2.67 ppm based on tetramethylsilane) was observed by NMR, and at 25°C.
The viscosity was measured. From the start of heating and stirring
After 12 hours, the peak due to protons of epoxide methylene disappeared, and before the start of heating and stirring,
The viscosity of the mixture, which was 100 cSt, reached 1800 cSt, so Methyl (γ-glycidoxypropyl) represented by
2.2 mol of dimethoxysilane was added, and heating and stirring was continued under the same conditions. Withdrawing a portion of the reaction mixture at 4 hour intervals after adding the silane,
When iodine was added to react with the mercapto group and the remaining iodine was back titrated with sodium thiosulfate to detect the mercapto group, it was no longer detected 12 hours after the addition of silane, so heating and stirring was stopped. , methanol was distilled off.
The resulting reaction product has a viscosity at 25℃.
It is a pale yellow viscous liquid with a specific gravity of 1.01 at the same temperature and a number average molecular weight of 6,500 as measured by GPC, and the molecular chain terminals are blocked with a hydrolyzable silyl group represented by the following formula. It was polyether (P-1). Synthesis Example 2 For 5 moles [10 (epoxy) equivalent] of glycidyl group-end-blocked polyoxypropylene having an average degree of polymerization of 32, a molecular weight of about 2000, and a viscosity of 550 cSt at 25°C,
6 moles of 2,5-dimercapto-1,3,4-thiadiazole and 10% of polyoxypropylene
An amount of ethanol corresponding to 1 was added, and heating stirring was started at 60°C under a nitrogen atmosphere. A portion was taken out at 4 hour intervals from the start of heating and stirring, and the peak due to protons of epoxide methylene was observed by NMR, and the viscosity at 25°C was measured. 12 hours after the start of heating and stirring, the peak due to protons of epoxide methylene disappeared, and the viscosity, which was 270 cSt before the start of heating and stirring, reached 4400 cSt. 2.2 mol of γ-glycidoxypropyltriethoxysilane represented by was added, and heating and stirring was continued under the same conditions. After adding the above silane, a portion was taken out at 4 hour intervals and the mercapto group was detected using the same method as in Synthesis Example 1. As the mercapto group was no longer detected 12 hours after the addition of the silane, heating and stirring was stopped. After distilling off the ethanol, the viscosity at 25℃ is 29000 cSt, and the specific gravity at the same temperature is
1.01, the number average molecular weight measured by GPC is
11,000 was obtained as a pale yellow viscous liquid (polyether whose molecular chain ends were blocked with a hydrolyzable silyl group represented by the following formula, P-2). Synthesis Example 3 For 3 moles [6 (epoxy) equivalents] of glycidyl group-end-blocked polyoxypropylene with an average degree of polymerization of 50, a molecular weight of approximately 3000, and a viscosity of 970 cSt at 25°C,
4 moles of 2,5-dimercapto-1,3,4-thiadiazole and 10% of polyoxypropylene
An amount of methanol corresponding to the above was added, and heating stirring was started at 60°C under a nitrogen atmosphere. A portion was taken out at 4 hour intervals from the start of heating and stirring, and the peak due to protons of epoxide methylene was observed by NMR, and the viscosity at 25°C was measured. 16 hours after the start of heating and stirring, the peak due to protons of epoxide methylene disappeared, and the viscosity, which was 420cSt before the start of heating and stirring, reached 5400cSt. 2.5 mol of phenyl(γ-glycidoxypropyl) dimemethoxysilane represented by was added, and heating and stirring was continued under the same conditions. After adding the above silane, a portion was taken out at 4 hour intervals and the mercapto group was detected using the same method as in Synthesis Example 1. As the mercapto group was no longer detected 16 hours after the addition of the silane, heating and stirring was stopped. After methanol was distilled off, a pale yellow viscous liquid with a viscosity of 26,000 cSt at 25°C, a specific gravity of 1.01 at the same temperature, and a number average molecular weight of 9,500 as measured by GPC (a hydrolyzable silyl compound represented by the following formula) was obtained. A polyether P-3) whose molecular chain ends were blocked with a group was obtained. Synthesis Example 4 Same as that used in Synthesis Example 3, average degree of polymerization 50,
For 3 moles [6 (epoxy) equivalents] of glycidyl group-end-blocked polyoxypropylene with a molecular weight of approximately 3000 and a viscosity of 970 cSt at 25°C,

4 moles of p-dimercaptobenzene represented by the formula and methanol in an amount equivalent to 10% of polyoxypropylene were added, and heating and stirring at 60°C under a nitrogen atmosphere was started. A portion was taken out at 4 hour intervals from the start of heating and stirring, and the peak due to protons of epoxide methylene was observed by NMR, and the viscosity at 25°C was measured.
12 hours after the start of heating and stirring, the peak due to protons of epoxide methylene disappeared and the viscosity, which was 400cSt before the start of heating and stirring, reached 5200cSt, so 2.2 mol of methyl (γ-glycidoxypropyl) dimethoxysilane was added. In addition, heating and stirring were continued under the same conditions. After adding the above silane, a portion was taken out at 4 hour intervals and the mercapto group was detected using the same method as in Synthesis Example 1. As the mercapto group was no longer detected 12 hours after the addition of the silane, heating and stirring was stopped. After methanol was distilled off, a pale yellow viscous liquid with a viscosity of 25,000 cSt at 25°C, a specific gravity of 1.01 at the same temperature, and a number average molecular weight of 9,500 as measured by GPC (a hydrolyzable silyl compound represented by the following formula) was obtained. A polyether P-4) whose molecular chain ends were blocked with a group was obtained. Synthesis Example 5 Same as that used in Synthesis Example 3, average degree of polymerization 50,
For 3 moles [6 (epoxy) equivalents] of glycidyl group-end-blocked polyoxypropylene with a molecular weight of approximately 3000 and a viscosity of 970 cSt at 25°C,

4 moles of 1,5-dimercaptonaphthalene represented by the formula and methanol in an amount equivalent to 10% of polyoxypropylene were added, and heating and stirring at 60°C under a nitrogen atmosphere was started. Partially removed at 4 hour intervals from the start of heating and stirring,
The proton peak of epoxide methylene was observed by NMR, and the viscosity at 25°C was measured. 12 hours after the start of heating and stirring, the peak due to protons of epoxide methylene disappeared, and the viscosity, which was 430 cSt before the start of heating and stirring, decreased.
Since the temperature reached 5500 cSt, 2.2 mol of methyl(γ-glycidoxypropyl)dimethoxysilane was added and heating and stirring was continued under the same conditions. After adding the above silane, a portion was taken out at 4 hour intervals and the mercapto group was detected using the same method as in Synthesis Example 1. As the mercapto group was no longer detected 12 hours after the addition of the silane, heating and stirring was stopped. After methanol was distilled off, a pale yellow viscous liquid with a viscosity of 27,000 cSt at 25°C, a specific gravity of 1.01 at the same temperature, and a number average molecular weight of 9,600 as measured by GPC (a hydrolyzable silyl compound represented by the following formula) was obtained. A polyether P-5) whose molecular chain ends were blocked with a group was obtained. Examples 1 to 5 Each polyether (P-1 to
5) To 100 parts, add the filler, inorganic pigment, and thixotropic agent shown in Table 1 and disperse them uniformly with a triple roll, and then add the organic tin compound shown in Table 1. Mix and sample-1
~5 were adjusted respectively. Using each of these samples,
Harden each sheet into a sheet approximately 2 mm thick at room temperature.
After curing for 14 days, punched JIS No. 2 dumbbells were subjected to a tensile test. Next, the dumbbell-shaped sample piece obtained in the same manner was placed in a 150°C dryer and a weather-o-meter, and subjected to the deterioration conditions (heating and ultraviolet irradiation) for the period shown in Table 1, and then the condition of the sample piece was evaluated. Observations and tensile tests were conducted. These results are also shown in Table 1. Comparative example 1 Molecular weight approximately 8000, as a terminal group

For 100 parts of polyoxypropylene having γ-methyldimethoxysilylpropoxy groups at both ends represented by the formula,
After adding the filler, inorganic pigment, and thixotropic agent shown in Table 1 and uniformly dispersing them with a triple roll, the organic tin compound also shown in Table 1 was added and mixed to obtain Sample-6. Ta. A test similar to that in Example was conducted using Sample-6. The results are also shown in Table 1. As shown in Table 1, the room temperature curable composition of the present invention has better heat resistance and UV resistance (weather resistance) than the conventional polymer composition of Comparative Example 1.
It is clear that there has been a marked improvement. Examples 6-10 Same samples-1-1 as those prepared in Examples 1-5
A shear adhesion test specimen shown in FIG. 1 was prepared using No. 5. After curing the prepared test specimens at room temperature for 28 days, a tensile test was conducted. The results are shown in Table 2. Comparative Example 2 Using the same sample 6 as prepared in Comparative Example 1, the same tests as in Examples 6 to 10 were conducted. The results are also shown in Table 2. As is clear from Table 2, the room temperature curable composition of the present invention was found to have extremely excellent adhesive properties.

【table】

【table】

【table】 [Brief explanation of the drawing]

FIG. 1 shows a perspective view of a specimen subjected to a shear adhesion test. The unit in the figure is mm. 1... Sample, 2... Adherent (glass, aluminum or PVC steel plate).

Claims (1)

[Claims] 1 (A) (A) General formula; (In the formula, R ¹ and R ² are divalent hydrocarbon groups, m is
Indicates a number from 10 to 500. ) Polyethers whose molecular chain ends are blocked with epoxy groups; (b) aromatic or heterocyclic compounds in which two mercapto groups are bonded to carbon atoms constituting an aromatic ring or heterocycle; c) A compound with a molecular weight of 1000 to 50000 obtained by reacting an organosilicon compound having an epoxy group and a hydrolyzable group.
100 parts by weight of a polyether whose molecular chain ends are blocked with a hydrolyzable silyl group (B) 3 to 300 parts by weight of an inorganic filler (C) 0.001 to 20 parts by weight of a curing catalyst. Curable composition. 2 (b) Component is 2,5-dimercapto-1,3,4
- a heterocyclic compound or an aromatic compound selected from thiadiazole, dimercaptobenzene, dimercaptotoluene, dimercaptoxylene, and dimercaptonaphthalene;
Compositions as described in Section. ³ Component (c) has ^the general formula; A non-hydrolyzable divalent hydrocarbon group consisting of a structure in which one or more methylene groups are substituted with oxygen, nitrogen and sulfur atoms or atomic groups, R ⁴ is a monovalent hydrocarbon group, Y is a hydrolyzable group bonded to a silicon atom, and a represents a number from 1 to 3.)
The composition according to claim 1, which is an organosilicon compound having an epoxy group represented by and a silicon-bonded hydrolyzable group. 4 (c) Component is a general formula; (In the formula, R ⁴ is the same as above, R ⁶ and R ⁷ are divalent hydrocarbon groups, R ⁸ is an alkyl group having 1 to 6 carbon atoms, and a is the same as above.)
The composition according to claim 1, which is an organosilicon compound represented by: 5 (b) Component is 2,5-dimercapto-1,3,4
- The composition according to claim 1, which is a thiadiazole. 6 (A) component is general formula (In the formula, X is a residue of the compound (b), a and m are the same as above, n is a number of 1 or more, R ¹ , R ² , R ⁴ ,
R ⁶ , R ⁷ and R ⁸ are the same as above)
The composition according to claim 1, which is a polyether represented by: