JPS6050363B2 - Production method of silicone-modified acrylic low molecular weight material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a low molecular weight silicone-modified acrylic material which can be converted into a comb-like elastic material at room temperature by the action of a catalyst and moisture.

As silicone-modified polymers that can be cured at room temperature by the action of moisture or catalysts, there are known silicone-modified polymers made by introducing silicon-bonded functional groups into the molecular chain ends of polymers such as polyether and polyurethane.

However, because the molecular skeleton of conventional polymers of this type consists of ether or urethane bonds, the cured product has poor weather resistance and other durability, and is not satisfactory in terms of mechanical strength, elongation, and other properties. I couldn't say it.
On the other hand, a mixed system of a low-molecular-weight acrylic copolymer and an isocyanate compound is known as a room-temperature-curable composition that does not require a solvent or dispersion medium and contributes to pollution prevention and durability. .

In this type of composition, the base polymer is made of acrylic, so the cured product has excellent weather resistance and other durability.
However, it has the disadvantage of being easily susceptible to thermal changes at temperatures above 10.0'C, and since it contains free isocyanate groups, it reacts with atmospheric moisture during curing to generate carbon dioxide gas. There was a tendency for the performance of the cured product to deteriorate due to the foaming phenomenon. Furthermore, with this type of composition, depending on the type of low molecular weight acrylic copolymer, sufficient mechanical strength and elongation properties may not be obtained in some cases. This invention was discovered as a result of intensive studies from the above viewpoint, and its gist is that a) an alkyl (meth)acrylate monomer whose alkyl group has 2 to 14 carbon atoms; ) glycidyl (meth)acrylate monomer and c) the following general formula; (wherein R1 is an alkyl group, R2 is a monovalent hydrocarbon group or triorganosiloxy group, R3 is a divalent hydrocarbon group, n is an integer consisting of 1, 2 or 3), the molar ratio of each of the above components is a:b:c=10-200:1-10: A low molecular weight copolymer is obtained by radical polymerization at a ratio of 0.01 to 1 part by weight of the polymerization initiator to a total of 10% by weight of the monomer component a (5b). Then, by subjecting the glycidyl group in the molecule of this copolymer to a polyaddition reaction with d) an aminosilane compound having a silicon-bonded functional group, an average of about 1 group based on the above component c is added to the molecular end of the copolymer. A method for producing a silicone-modified acrylic low-molecular weight product, which comprises introducing a silicon-bonded functional group and an average of about one silicon-bonded functional group based on component d at any position within the copolymer molecule. .

The low molecular weight product obtained by the method of this invention has an average of about one silicon-bonded functional group at each end of the molecule and at any position within the molecule, so it is a telechelic type low molecular weight product that has functional groups at both ends of the molecule. By adding catalysts such as metal organic acid salts and organic amines at room temperature and allowing moisture to act on it, the molecular weight is increased in linear and network forms, resulting in excellent physical properties. A cured product having give.

In other words, this cured product is a rubber-like elastic body that has improved mechanical strength and elongation properties, and has good heat resistance that does not undergo large thermal changes even when left at temperatures of 100°C or higher. becomes. Further, since this rubber-like elastic body is originally made of an acrylic polymer, it also has excellent weather resistance and other durability. Furthermore, since the low molecular weight substance obtained by the above-mentioned method of the present invention is normally liquid at room temperature, it does not require a solvent or dispersion medium to be used, and is easy to use in terms of pollution prevention, ease of administration, and ease of use. Good results can be obtained in terms of properties, etc., and since there is almost no foaming phenomenon as in conventional methods during curing, there is no deterioration in the properties of the cured product due to this phenomenon. The alkyl (meth)acrylate monomer used as component a in this invention is one in which the alkyl group has 2 to 14 carbon atoms, and the above carbon j prime number is 2.
If it is less than 14 or more than 14, the physical properties of the cured product, such as flexibility and adhesiveness, will be impaired and its utility value for various purposes will be reduced.

The above alkyl group may be branched or unbranched, and specifically includes ethyl, n-butyl, isobutyl,
1-ethylpropyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 1-ethylbutyl, 2
-Ethylbutyl, isoquotyl, 3,5,5-trimethylhexyl, decyl, dodecyl and the like. Two or more of these alkyl (meth)acrylate monomers can be used in combination if necessary. In this invention, up to about half of the above monomers for component a can be copolymerized with other monomers. can be substituted with an unsaturated monomer.
Examples of such monomers include vinyl esters, vinyl pyridine, vinyl ethers, acrylonitrile,
Methacrylonitrile, methylene glutaronitrile, methyl methacrylate, NleN-dimethylaminoethyl methacrylate, butadiene, styrene, chloroprene,
Examples include acrylamide. The types and proportions of these monomers may be appropriately determined depending on the purpose of use, but if the amount used is more than half, the characteristics of the acrylic type will be diminished. In this invention, component b used together with component a or its substituted component is glycidyl acrylate or glycidyl methacrylate,
The idea is to introduce a glycidyl group corresponding to an arbitrary position within the molecule of a low molecular weight copolymer, and then react it with an aminosilane compound to finally introduce a silicon-bonded functional group at the above position. The chain transfer agent used as component c in this invention usually has 1 to 6 carbon atoms, preferably 1 as a silicon-bonded functional group represented by the above general formula.
It has ~2 alkoxy groups (RlO groups) and is used to introduce the above-mentioned functional group to the end of the polymer chain by chain transfer by hydrogen abstraction of the SH group.

In the general formula, n is an integer of 1 to 3, but dialkoxysilanes with n=2, such as γ-mercaptopropylmethyldimethoxysilane, give particularly good results in the rubber elasticity of the cured product. Further, when a relatively hard elastic body which does not require much flexibility in the cured product is desired, a trialkoxysilane in which n=3, such as γ-mercaptopropyltrimethoxysilane, is effective. Monoalkoxysilanes with n = 1 have lower practical value than those with n = 2 and 3 because the reactivity of the low molecular weight products obtained from them is lower, but they can be used satisfactorily depending on the purpose of use. It is possible. In this invention, the monomer components A and b are radically polymerized in the presence of the chain transfer agent, and at this time, the ratio of each component used is set within a specific range to form a glycidyl group based on component b. Approximately 1 on average at any position within the polymer molecule
At the same time, on average, about one silicon-bonded functional group based on component c must be introduced at the end of the molecule.

In other words, the ratio of each component used is not necessarily constant depending on the type and reactivity of components A, b, and c, but even if all these factors are taken into account, A range in which the b component monomer is 1 to 10 mol and the a component monomer is 10 to 100 mol, that is, a:b:
The molar ratio should be in the range c=10-200:1-10:1, and if it deviates from this range, it will be difficult to introduce the above-mentioned functional groups in any case.

Radical polymerization using the above proportions is carried out using a suitable polymerization initiator, such as common polymerization initiators such as α・α″-azobisisobutyronitrile, benzoyl peroxide, and redox catalysts. Any of those used as a radical polymerization catalyst can be used.

The amount of this polymerization initiator used should be 0.01 to 1 part by weight per 10 parts by weight of the monomer component a < 5b, and even if this is too much, it is also not too small. Also, it is difficult to perform good radical polymerization. For radical polymerization,
The monomer components may be added in their entirety at once from the beginning of the polymerization, or only a portion may be added at first and the remaining portion may be added dropwise as the polymerization reaction progresses.

The latter case is advantageous for those in which polymerization heat generation tends to be a problem, and in this case, it is preferable to use a low molecular weight copolymer or plasticizer that has been polymerized on a small scale in place of the solvent. The chain transfer agent and polymerization initiator as component c may also be charged in the same manner as above, and when only a portion is initially charged, it is preferable to dissolve the remaining amount in the monomer component. As the polymerization method, it is preferable to adopt a bulk polymerization method and carry out the polymerization without using a solvent. The polymerization conditions are adjusted so that no gel-like copolymer is formed or the monomers of the final reaction remain as little as possible, but the polymerization temperature is particularly adjusted to 50 to
The temperature is preferably 120°C, preferably in the range of 60 to 100°C. Since the chain transfer agent as component c plays the role of a polymerization degree regulator, polymerization control is relatively easy. The end point of the polymerization reaction is usually the point at which no heat generation occurs. The low molecular weight copolymer obtained in this way is then subjected to a polyaddition reaction with an aminosilane compound having a silicon-bonded functional group as a component d to the glycidyl group introduced by the component b into the copolymer. It is subjected to a process of That is, a silicon-bonded functional group is introduced into an arbitrary position (the position of a glycidyl group) within the copolymer molecule by the above-mentioned polyaddition reaction. The aminosilane compound used here as the d component usually has an alkoxy group as a silicon-bonded functional group in addition to an amino group that reacts with a glycidyl group, and the silicon-bonded functional group may have other functional groups as the case may be. For example, it may be a halogen.

A specific example of such an aminosilane compound is N-β (aminoethyl) represented by the following chemical structural formula -A.
γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl)γ- represented by the following chemical structural formula -B
Examples include aminopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane represented by the following chemical structural formula 1C, and γ-aminopropylmethyldimethoxysilane represented by the following chemical structural formula -D. Theoretically, the proportion of aminosilane compounds to be used may be equivalent to that of the glycidyl group, but in consideration of reactivity, it is generally necessary to use a proportion of 1 to 2 equivalents of amino group per equivalent of glycidyl group. It is better to do so.

The polyaddition reaction of the aminosilane compound is about 120 to 2
This can be carried out by heating and mixing at 00°C for 1 to 3 hours, and at this time, it is sufficient to uniformly mix the entire amount at once from the beginning. The reaction can be accelerated using, for example,

The end point of the reaction can be confirmed by the disappearance of the absorption of glycidyl groups in the infrared absorption spectrum. The silicone-modified acrylic low-molecular weight product thus obtained has an average of about one silicon-bonded functional group based on the chain transfer agent as component c at the end of the molecule, and an average of about one silicon-bonded functional group based on the aminosilane compound as component d at any position within the molecule. About one silicon-bonded functional group is introduced, and the molecular weight is usually 1,000 to 30.
0(4) and is generally liquid at room temperature.

The above-mentioned low molecular weight acrylic material according to the present invention can be easily cured at room temperature by blending an appropriate catalyst and applying moisture due to the reactivity of the silicon-bonded functional group contained therein. This curing gives a rubber-like elastic body with the excellent characteristics mentioned above, so it can be widely applied to sealants, adhesives, paints, electrical insulation materials, etc.

The above catalysts include metal organic acid salts such as tin octylate, dibutyltin diurarate, lead octylate, dibutylamine, triethanolamine, dimethyl soyaamine,
Examples include organic amines such as tetramethylguanidine and diphenylguanidine, but other catalysts may also be used.

When applying the low-molecular-weight acrylic material of the present invention to the various uses mentioned above, it is possible to use a two-component form in which it and the catalyst are mixed at the time of use, or if necessary, both may be mixed in advance. It is also possible to mix the mixture in a moisture-free state, fill it in a sealed container, store it, and take it out at the time of use. Next, examples of this invention will be described. In the following, parts and % shall mean parts by weight and % by weight. Example 1 A mixture was prepared consisting of 9 parts of n-butyl acrylate, m parts of acrylonitrile, 4.3 parts of glycidyl acrylate, and 6 parts of γ-mer captopropylmethyldimethoxysilane. 30% of this mixture was added to 200 cc of The mixture was placed in a four-hole flask, and the inside of the flask was replaced with nitrogen while stirring, and the inner bath was heated to 70°C.

After replacing the powder with nitrogen, add α●α5 as a polymerization initiator.
-0.1 part of azobisisobutyronitrile was added. Polymerization started and generated heat, but after the heat generation slowed down a little, 0.1 part of α・α″-azobisisobutyronitrile was added to the remaining 70% of the above mixture and gradually poured into the flask by dropwise loading. In addition to that. The dropping time was 3 hours, and the polymerization was terminated when no heat generation was observed. The polymerization rate was 99%. Next, 6.8 parts of N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane was charged to 110.4 parts of the low-molecular-weight acrylic material obtained as above in the same flask, and 130 parts of
The polyaddition reaction was carried out for 3 hours while maintaining the temperature at °C.

The end point of this reaction was confirmed by tracking the glycidyl group of the low molecular weight product by infrared absorption analysis. The silicone-modified acrylic low molecular weight material thus obtained had a viscosity (Bruckfield viscosity) of 20 poise/30° C1 and an average molecular weight (by vapor pressure osmosis method) of 5,800.

Furthermore, when the number of alkoxy groups as silicon-bonded functional groups contained in one molecule was investigated by molecular weight and elemental analysis, the average number of alkoxy groups was about two. From this result and the mechanism of the polymerization reaction, it was found that an average of about one of the above functional groups was introduced at the end of the molecule and at any arbitrary position within the molecule. In order to investigate the properties of the cured product of this silicone-modified acrylic low molecular weight material, 100% of the above low molecular weight material
1 part tin octylate and 1 part tetramethylguanidine
After uniformly mixing the parts, 277177! A thick sheet was prepared and cured at 20°C and 60% RH for 7 days and then at 50'C for 7 days.

However, when I investigated the mechanical strength of the product according to JISK-6301, I found that it was a good thing! - As is clear from the above, it can be seen that the above-mentioned low molecular weight material is cured by the action of a catalyst and moisture to provide a rubber-like elastic material having good properties. Furthermore, no foaming phenomenon was observed during the curing process. Example 2 n-butyl acrylate part, w part acrylonitrile, 2.2 parts glycidyl acrylate, γ-mercaptopropylmethyldimethoxysilane 3. A mixture consisting of (2) was prepared.

Along with this mixture, α●α″-azobisisobutyronitrile was added as a polymerization initiator to 1 (1) part of the above monomers in an amount of 0.
．． A polymerization reaction was carried out in the same manner as in Example 1 using 1 part of the solution. The polymerization rate was 99%. Next, 3.5 parts of N-β(aminoethyl)γ-meaminopropyltyldimethoxysilane was added to 105.3 parts of the acrylic low molecular weight product obtained as above, and the same procedure as in Example 1 was added. A polyaddition reaction was carried out.

The silicone-modified acrylic low molecular weight product thus obtained had a viscosity of 32 poise/30'C and an average molecular weight of 12,000. The number of silicon-bonded functional groups per molecule was about 2 on average. When the properties of the cured product of this silicone-modified low-molecular-weight acrylic material were investigated in the same manner as in Example 1, it was found that a rubber-like elastic material having the same excellent properties as in Example 1 was obtained.

Example 3 A mixture consisting of 1 (1) part of n-butyl acrylate, 1.5 parts of glycidyl acrylate, and 2.1 parts of γ-mercaptopropylmethyldimethoxysilane was prepared.

Along with this mixture, α·α″-azobisisobutyronitrile was added as a polymerization initiator in an amount of 0.0% per 100 parts of the above monomers.
A polymerization reaction was carried out in the same manner as in Example 1 using 1 part of the solution. The polymerization rate was 99%. Next, 2.4 parts of N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane was added to 103.6 parts of the acrylic low molecular weight product obtained as above, and the same procedure as in Example 1 was carried out. A polyaddition reaction was performed.

The silicone-modified acrylic low molecular weight material thus obtained had a viscosity of 76 poise/300C1 average molecular weight of 19,000. Moreover, the number of silicon-bonded functional groups per molecule was about 2 on average. In order to investigate the properties of the cured product of this silicone-modified acrylic low molecular weight material, 100 parts of the above low molecular weight material was mixed with surface-treated calcium carbonate 15 (4
) Add 30 parts of starved titanium oxide, 1 part of carbon black, 2 parts of hydrogenated castor oil as an anti-sagging agent, and 0.5 part of benzotriazole as an anti-aging agent, and knead with a kneader.
After scouring by passing through a book roll, the mixture was suctioned under reduced pressure using a planetary mixer and heated and stirred.

To 1 (1) part of this mixture, 0.5 part of tin octylate and 0.5 part of diphenylguanidine were added and mixed uniformly to prepare an H-type test specimen according to JISA-5758. Next, this test specimen was subjected to standard curing at 20'C x 60% RH for 7 days and further at 50°C for 7 days. Afterwards,
Regarding this mechanical strength, etc., the initial value and 14 at 100°C
When I checked the value after heating for several days, I found that
Initial value Tensile strength after heating (Kg/d)
7.48.2 Elongation (%) 560
The hardness was 540 (Shoer A) and 1618.

As is clear from this, it can be seen that the above-mentioned low molecular weight material is B because it is cured by the action of a catalyst and moisture to give a rubber-like elastic material having good physical properties. especially,
The above test shows that a rubber-like elastic body with excellent heat resistance can be obtained. Example 4: 1 part of ethyl acrylate, 10 parts of acrylonitrile, 1 part of glycidyl methacrylate. A mixture consisting of 4 parts of γ-mercaptopropyltrimethoxysilane and 1.5 parts of γ-mercaptopropyltrimethoxysilane was prepared.

Along with this mixture, α・α″-azobisisobutyronitrile was added as a polymerization initiator to 1 (1) part of the above monomer.
．． A polymerization reaction was carried out in the same manner as in Example 1 using 1 part of the polymer. The polymerization rate was 100%. Next, 21 parts of N-β(aminoethyl)γ-aminopropylmethoxysilane was added to 103.0 parts of the acrylic low molecular weight product obtained as above, and polyaddition reaction was carried out in the same manner as in Example 1. I did this.

The silicone-modified acrylic low molecular weight material thus obtained had a viscosity of 92 poise/30° C. and an average molecular weight of 21,000. Further, the number of silicon-bonded functional groups per molecule was about 2.3 on average. In order to investigate the properties of the cured product of this silicone-modified acrylic low molecular weight product,
After uniformly mixing 1 part of dibutyltin dilaurate with 100 parts of the above low molecular weight substance, 2T! A $t-thick sheet was prepared and heated at 20°C and 60% RH for 7 days, then at 50°C.
It was cured for 7 days. After that, we examined its mechanical strength according to JISK-6301, and found that the tensile strength was 8.5 kg/Cfl elongation.
320% hardness (Shorr A) 38.

Claims (1)

[Scope of Claims] 1 a) an alkyl (meth)acrylate monomer whose alkyl group has 2 to 14 carbon atoms, b) a glycidyl (meth)acrylate monomer, and c) the following general formula; There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R_1 is an alkyl group, R^2 is a monovalent hydrocarbon group or triorganosiloxy group, R^3 is a divalent hydrocarbon group, and n is 1, 2, or 3. in the presence of a chain transfer agent having a silicon-bonded functional group represented by
The molar ratio of each of the above components is a:b:c=10~200:1~
A low molecular weight copolymer is obtained by radical polymerization at a ratio of 10:1 and a ratio of 0.01 to 10 parts by weight of the polymerization initiator to a total of 100 parts by weight of the monomer components a and b. Then, by subjecting the glycidyl group in the molecule of this copolymer to a polyaddition reaction with d) an aminosilane compound having a silicon-bonded functional group, an average of about 1 silicon based on the above component c is added to the molecular end of the copolymer. An average of 1 based on the bonding functional group and the above d component at any position within the copolymer molecule.
1. A method for producing a low molecular weight silicone-modified acrylic material, which comprises introducing silicon-bonded functional groups.