JPH09176277A - Silane-modified polymer and method for producing the same - Google Patents

Abstract

(57) Abstract: [PROBLEMS] To provide a silane-modified polymer having low tackiness and capable of obtaining a highly stretchable rubber-like elastic body, and a method for producing the same. SOLUTION: General formula (1): [Wherein R is an alkylene group (provided that all R groups are 30
Mol% or more is an alkylene group composed of a main chain having 4 to 7 carbon atoms), R ¹ is a divalent organic group, R ² is a monovalent hydrocarbon group, and R ³ is Is a divalent organic group, a plurality of X are independently a monovalent group or atom selected from the group consisting of an alkoxy group, a ketoxime group and a halogen atom, and a plurality of n are independently an integer of 5 to 1000. And m is 1
Is an integer of 4 and a is 0 or 1.].

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel silane-modified polymer, a method for producing the same, and a room temperature curable composition using the silane-modified polymer, and more particularly to a silane-modified polymer useful as a sealing material for buildings and the like. .

[0002]

A rubber-like elastic material obtained by curing a composition comprising a silane-modified polymer, a curing catalyst, a filler and the like is used as a sealing material, caulking material, etc. in the fields of buildings, ships, automobiles and roads. Widely used. Among the above compositions, the room temperature curable polyether composition comprising a polyether having an ethylenic double bond such as an allyl group at the molecular end, hydrogen silane and a platinum catalyst has a high elongation in the cured product obtained. In addition, it has the advantage of being inexpensive. However, in this composition, platinum used as a catalyst is susceptible to a catalyst poison. Also, polyethers are usually
It is obtained in the form of having a hydroxyl group at both ends, but the hydroxyl group at both ends must be replaced with a group having an ethylenic double bond such as an allyl group so that it can be reacted with hydrogensilane. As a solution to the above drawbacks, JP-A-3-43449 discloses a silane-modified polymer obtained by reacting a silane coupling agent having an isocyanato group with a polyether diol having hydroxyl groups at both ends. Has been done.

[0003]

However, after adding a silica-based filler, a curing agent such as methyltrimethoxysilane, and a catalyst such as dibutyltin dioctate to the silane-modified polymer to obtain a composition, The cured product obtained by curing has a high tackiness and becomes a rubber-like elastic body with low elongation. The reason why a highly stretchable rubber-like elastic body cannot be obtained is considered to be due to the small molecular weight of the polyether. Therefore, an object of the present invention is to provide a silane-modified polymer having a low stickiness and a highly stretchable rubber-like elastic body, and a room temperature curable composition using the same.

[0004]

In order to solve the above-mentioned problems, the present invention has the general formula (1):

[0005]

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[In the formula, R is an alkylene group (provided that 30 mol% or more of all R are alkylene groups composed of a main chain having 4 to 7 carbon atoms), and R ¹ is a divalent group. An organic group, R ² is a monovalent hydrocarbon group, R ³ is a divalent organic group, a plurality of X is independently selected from the group consisting of an alkoxy group, a ketoxime group and a halogen atom. A valent group or atom, a plurality of n are independently an integer of 5 to 1000, m is an integer of 1 to 4, and a is 0 or 1]. .

Furthermore, as a method for producing the silane-modified polymer, (A) formula (2): HO - at (RO-) _n H (2) [wherein, R and n are as defined above] The polyether diol compound shown is reacted with a diisocyanate compound represented by OCN-R ³ -NCO (3) [wherein R ³ has the same meaning as described above], and a compound represented by the formula (4):

[0008]

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A step of producing a compound represented by the formula: wherein R, R ³ , m and n have the same meanings as defined above, and
(B) The compound represented by the above formula (4) can be prepared by converting the compound of the formula (5): OCN-R ¹ -Si (R ² ) _a X _3-a (5) [wherein R ¹ , R ² , X and a are Has the same meaning as above].

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION (Silane-modified polymer) The silane-modified polymer has a polyether group and a hydrocarbon group (the carbon atom may be substituted with silicon or nitrogen, as shown in the general formula (1). ) Or a group having a siloxane bond is repeated via a urethane bond, and both ends of the molecular chain are required to have a structure sealed with a trisubstituted silyl group.

R in the general formula (1) is an alkylene group, preferably an alkylene group having 1 to 7 carbon atoms, which may be linear or branched. However, 30 mol% or more, preferably 50 mol% or more, and more preferably 10 mol% or more of all Rs in the general formula (1).
0 mol% is an alkylene group having 4 to 7 carbon atoms in the main chain (hereinafter referred to as R '), preferably 4 carbon atoms in the main chain.
5 to 5, more preferably an alkylene group having 4 carbon atoms in the main chain (that is, 1,4 butylene type). That is, the polyether group in the silane-modified polymer represented by the general formula (1) may contain less than 70 mol% of those having a main chain of less than 4 carbon atoms, such as polyethylene glycol, preferably all main groups. Chain has 4 to 4 carbon atoms
7 When the number of carbon atoms in the main chain of R ′ is less than 4, the rubber-like elastic body (hereinafter, referred to as a cured product) obtained by curing the composition of the present invention after preparation is considered to have large tackiness. Become. On the other hand, if it is larger than 7, the melting point of the silane-modified polymer itself becomes high, and it becomes difficult to manufacture.

As a specific example of R ',

[0013]

Embedded image Are shown.

The polymerization degree of n in the general formula (1), that is, the degree of polymerization of the polyether group is independently an integer of 5 to 1000, preferably an integer of 10 to 100. If the degree of polymerization is less than 5,
The resulting cured product has poor elasticity. On the other hand, when it is more than 1000, the viscosity becomes high and the production becomes difficult.

The polyether group represented by-(RO-) _n may independently be a homopolymer or a copolymer, and further, one having less than 4 carbon atoms in the main chain (eg polyethylene glycol), Number of carbon atoms in the chain is 4-7
It may also be a copolymer with that of poly (1,4-butylene glycol).

R ¹ in the general formula (1) represents a divalent organic group, for example, an alkylene group having 1 to 7 carbon atoms such as a methylene group, an ethylene group and a butylene group; an arylene group such as a phenylene group; A divalent hydrocarbon group such as a combination of an alkylene group and an arylene group (in which case, a part of carbon atoms in the divalent hydrocarbon group may be substituted with a nitrogen atom, a silicon atom or the like); Valent organosiloxane groups.
An alkylene group and a phenylene group-containing group are preferable, and an alkylene group is particularly preferable.

Specific examples of R ¹ include-(CH ₂ ) ₃ -,-(CH ₂ )
_{4 -, -CH (CH 3)} CH 2 CH 2 -, - CH (CH 3) CH (CH 3) CH 2 -,

[0018]

[Chemical 6]

[0019]

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A group represented by the formula: [wherein R ⁴ is a monovalent hydrocarbon group] can be mentioned. The R ⁴ usually has 1 carbon atom
-7, preferably 1-3 alkyl groups, preferably methyl groups.

Examples of the divalent organic group represented by R ³ in the general formula (1) include the same groups as R ^1, and an alkylene group and a phenylene group-containing group are preferable, and particularly preferably the following formula:

[0022]

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Is a group represented by

M in the general formula (1) is an integer of 1 to 4, preferably an integer of 1 to 2. When m is less than 1, tackiness of the obtained cured product is increased and rubber elasticity is poor. On the other hand, if it is larger than 4, the number of urethane bonds increases and the weather resistance may deteriorate.

R ² in the general formula (1) includes, for example, an alkyl group having 1 to 7 carbon atoms such as a methyl group and an ethyl group; an aryl group such as a phenyl group, and preferably a methyl group.

X in the general formula (1) is a group or atom selected from the group consisting of an alkoxy group, a ketoxime group and a halogen atom, and specifically, the following formulas: -OCH ₃ , -OCH ₂ CH _3,

[0027]

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The groups or atoms represented by the formula ( ₁₎ and the like are mentioned, and preferably -OCH ₃ and -OCH ₂ CH ₃ . When a plurality of Xs are present, they may be used alone or in combination of two or more.

The silane-modified polymer of the general formula (1) may have an average molecular weight of usually 2,000 to 50,000, preferably 3,000.
It is 0 to 8,000. Therefore, the viscosity of the silane-modified polymer is usually 50 to 1,500 P (poise), preferably 150 to 1,000 P at 25 ° C.

(Method for producing silane-modified polymer) As a method for producing the above-mentioned silane-modified polymer, for example, the following (A)
And a method comprising the steps (B).

Step (A) First, a polyether diol compound represented by the formula (2): HO 2 — (RO—) _n H (2) [wherein R and n have the same meanings as described above], and OCN -R ³ -NCO (3) [wherein R ³ has the same meaning as described above] is reacted with a diisocyanate compound to give a compound of formula (4):

[0032]

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A compound represented by the formula: wherein R, R ³ , m and n have the same meanings as described above is produced. The polyether diol compound represented by the formula (2) and the diisocyanate compound represented by the formula (3) may be used either individually or in combination of two or more.

In the above reaction, the reaction molar ratio between the polyether diol compound represented by (2) and the diisocyanate compound is usually 1 / 0.3 to 1 / 0.7, preferably 1 / 0.4 to 1 / It is 0.6.

The above reaction may be carried out at a temperature of 50 to 150 ° C. for usually 3 to 8 hours.

In the step (B) , the compound represented by the formula (4) obtained in the step (A) is converted into the compound represented by the formula (5): OCN-R ¹ -Si (R ² ) _a X _3-a (5) By reacting with a silane compound represented by the formula [wherein R ¹ , R ² , X and a have the same meanings as described above], a compound represented by the general formula (1) is obtained.

The silane compound represented by the formula (5) and the formula (4)
The reaction molar ratio with the compound represented by is usually 1 / 0.3 to
It may be 1 / 0.7, preferably 1 / 0.4 to 1 / 0.6.

The above reaction may be carried out at a temperature of 50 to 150 ° C. for 3 to 8 hours.

In order to improve the reaction efficiency and workability in the steps (A) and (B), a catalyst such as an organic tin compound or an alkaline compound, and an organic solvent may be used in each step. Examples of the organic solvent include hexane, toluene, benzene, xylene, tetrahydrofuran, diethyl ether and the like, and examples of the alkaline compound include triethylamine, aniline, dimethylaniline, tetramethylguanidine and the like. These may be used alone or in combination of two or more. Further, the blending amount of these may be appropriately determined according to the reaction.

(Room-Temperature-Curable Composition) The silane-modified polymer of the present invention is useful as a raw material for a room-temperature-curable composition, and a curing catalyst and, if necessary, an additive are added to the silane-modified polymer. When added, a room temperature curable composition can be obtained.

Therefore, the present invention further provides a room temperature curable composition comprising (a) a silane-modified polymer represented by the general formula (1) and (b) a curing catalyst.

Examples of the curing catalyst (b) include organic tin compounds such as dibutyltin dilaurate, dibutyltin dioctate, dibutyltin dipropionate, dibutyltin diethoxide and dibutyltin dinonate, and dibutyltin dilaurate is preferable.

The compounding amount of the curing catalyst may be a so-called catalytic amount, and is usually 0.01 per 100 parts by weight of the silane-modified polymer.
-20 parts by weight, preferably 0.1-10 parts by weight.

Other additives may be added to the above composition, if desired. Examples thereof include titanium oxide, calcium carbonate, silicon dioxide, talc, zinc carbonate, carbon black, aluminum oxide, and boron nitride. The amount of the additive compounded may be appropriately determined within a range that does not impair the desired physical properties.

The composition thus obtained is left to stand at room temperature to cure to a rubber-like elastic body.

The obtained rubber-like elastic body has no tackiness,
Since it has high extensibility, it is useful as a sealing material, a caulking material and the like used in buildings, ships, automobiles, roads and the like.

[0047]

The present invention will be described in detail below with reference to specific examples. In the formula below, Me represents a methyl group.

(Synthesis of Silane-Modified Polymer) [Example 1] A reaction vessel equipped with a stirrer having an inner volume of 500 mL was
Replaced by nitrogen, OH value (hydroxyl value) is 52 (KOH mg / g)
(In other words, 300 g of poly-1,6-hexylene glycol having a polymerization degree of 10) and 8.9 g of 1,3-diisocyanatopropane were added. Then, the temperature was raised to 60 ° C. and the temperature was maintained for 3 hours. Then, it cooled to room temperature and obtained the oily compound.

When the IR spectrum of this compound was measured, no peak appeared at around 2180 cm ^-1 (the characteristic absorption of the isocyanato group).

28.4 g of γ-isocyanatopropyltrimethoxysilane was added to the above oily compound, the temperature was raised to 60 ° C., and the temperature was maintained for 3 hours. Then, it cooled to room temperature and obtained 310 g of compounds. When the IR spectrum of this compound was measured in the same manner as above, the characteristic absorption of the isocyanato group did not appear. Thus the formula:

[0051]

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A silane-modified polymer represented by This compound is called a silane-modified polymer. The viscosity of this polymer was 300 P (40 ° C.).

[Example 2] The amount of 1,3-diisocyanatopropane of Example 1 was changed from 8.9 g to 4.5 g, and the amount of γ-isocyanatopropyltrimethoxysilane was changed from 28.4 g to 3 g.
By the same operation as in Example 1 except that the amount was changed to 4.4 g,
formula:

[0054]

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300 g of a silane-modified polymer represented by
Obtained. The viscosity of this polymer was 280 P (40 ° C.).

[Example 3] 300 g of poly (1,6-hexylene glycol) of Example 1 was replaced with 300 g of poly (1,4-butylene glycol) having an OH value of 55 (that is, a degree of polymerization of 15) to prepare 1,3-diethylene glycol. The amount of isocyanatopropane was changed from 8.9 g to 9.3 g and γ-
Change the amount of isocyanatopropyltrimethoxysilane to 28.4
By the same operation as in Example 1 except that g was changed to 30.1 g, the formula:

[0057]

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310 g of a silane-modified polymer represented by The viscosity of this polymer was 250 P (40 ° C.).

Example 4 A reaction vessel equipped with a stirrer having an internal volume of 500 mL was replaced with nitrogen, and 150 g of poly-1,4-butylene glycol having an OH value of 55 (that is, a degree of polymerization of 15) and an OH value of 55 were used.
Polypropylene glycol with a degree of polymerization of 18
150g and diphenylmethane-4,4 'diisocyanate
61.3g was added. Then, the temperature was raised to 60 ° C. and the temperature was maintained for 3 hours. Then, it cooled to room temperature and obtained the oily compound. To the above oily compound, 30.1 g of γ-isocyanatopropyltrimethoxysilane was added, and 60
The temperature was raised to ℃ and kept at the same temperature for 3 hours. Then cool to room temperature and formula:

[0060]

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340 g of a silane-modified polymer represented by The viscosity of this polymer was 340 P (25 ° C.).

Example 5 A reaction vessel equipped with a stirrer and having an internal volume of 1000 mL was replaced with nitrogen, and 500 g of poly-1,4-butylene glycol having an OH value of 29.5 (that is, a degree of polymerization of 30) and diphenylmethane-4, 16.9 g of 4'diisocyanate was added. Then, the temperature was raised to 60 ° C. and the temperature was maintained for 3 hours. Then, it cooled to room temperature and obtained the oily compound. 24.7 g of γ-isocyanatopropylmethyldimethoxysilane was added to the above oily compound, the temperature was raised to 60 ° C., and the temperature was maintained for 3 hours. Then cool to room temperature and formula:

[0063]

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340 g of a silane-modified polymer represented by The viscosity of this polymer was 310 P (25 ° C.). When the IR spectra of the oily intermediate products produced in Examples 2 to 5 and the silane-modified polymers were measured, characteristic absorption of the isocyanato group did not appear.

(Preparation of room temperature curable composition) [Examples 6 to 10] To 100 g of the silane-modified polymers obtained in Examples 1 to 5, 0.3 g of dibutyltin dilaurate as a curing catalyst was added, respectively. A room temperature curable composition was prepared. Next, this composition was molded into a sheet having a thickness of 2 mm, cured at a temperature of 20 ° C. for 7 days, and cured to prepare a rubber-like elastic body. The rubber physical properties of the obtained rubber-like elastic body were measured according to JIS-K-6301. Table 1 shows the results. Further, the stickiness of the rubber-like elastic body was measured by using an inclined type adhesive force measuring device by ball duck (J. Daw method). Table 1 shows the results. It should be noted that the smaller the numerical value of the adhesiveness, the lower the adhesiveness.

[Comparative Example 1] Methyldimethoxysilane was added to a polypropylene glycol (polymerization degree: 20) having hydroxyl groups at both terminals replaced with allyl groups to prepare a methyldimethoxysilane-modified polymer at both terminals. A room temperature curable composition was prepared and then cured in the same manner as in Example 6 except that the silane modified polymer was used instead of the silane modified polymer to prepare a rubber-like elastic body. Next, the rubber physical properties and tackiness of the obtained rubber-like elastic body were measured in the same manner as in Example 6. Table 1 shows the results.

Comparative Example 2 γ-isocyanatopropyltrimethoxysilane was subjected to an addition reaction with polypropylene glycol having hydroxyl groups terminated at both ends and having an OH value of 55 mg / g (that is, a degree of polymerization of 15) to give a polymer modified with trimethoxysilane at both ends. Prepared. A composition was prepared and cured in the same manner as in Example 6 except that the silane-modified polymer was used instead of the silane-modified polymer to prepare a rubber-like elastic body.
Next, the rubber physical properties and tackiness of the obtained rubber-like elastic body were measured in the same manner as in Example 6. Table 1 shows the results.

[0068]

[Table 1]

[0069]

According to the present invention, a novel silane-modified polymer and a room temperature curable composition using the same are provided. The rubber-like elastic material obtained by curing this composition has low tackiness and excellent rubber physical properties, and is therefore useful as a sealing material for construction, caulking material and the like.

Claims (3)

[Claims] [Claim 1] General formula (1): [Wherein R is an alkylene group (provided that all R groups are 30
Mol% or more is an alkylene group composed of a main chain having 4 to 7 carbon atoms), R ¹ is a divalent organic group, R ² is a monovalent hydrocarbon group, and R ³ is Is a divalent organic group, a plurality of X are independently a monovalent group or atom selected from the group consisting of an alkoxy group, a ketoxime group and a halogen atom, and a plurality of n are independently an integer of 5 to 1000. And m is 1
Is an integer of 4 and a is 0 or 1.]. 2. A polyether diol compound represented by the formula (A): HO-(RO-) _n H (2) [wherein R and n have the same meanings as described above], and OCN- R ³ -NCO (3) [wherein R ³ has the same meaning as described above] is reacted with a diisocyanate compound to give a compound represented by the formula (4): [Wherein R 1, R ³ , m and n have the same meanings as described above], and (B) the above formula (4)
A compound represented by the formula (5): OCN-R ¹ -Si (R ² ) _a X _3-a (5) [wherein R ¹ , R ² , X and a have the same meanings as described above] The method for producing a silane-modified polymer according to claim 1, comprising a step of reacting with a silane compound represented by. 3. A room temperature curable composition comprising (a) the silane-modified polymer according to claim 1 and (b) a curing catalyst.