JPS6367806B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a liquid diene copolymer, and more particularly to a method for producing a curable grafted liquid diene copolymer having excellent strength, weather resistance, and the like. BACKGROUND ART Conventionally, a polymer is known in which a polymerizable unsaturated group-containing compound is reacted with active hydrogen of a liquid diene-based polymer containing an active hydrogen group. These compositions are prepared by adding photopolymerization initiators or free radical initiators, and are widely used in paints, coating agents, adhesives, and the like. However, cured coatings obtained from conventionally commonly used curable liquid diene polymers have the drawback of insufficient mechanical strength such as tensile strength and tear strength. In addition, the permeability of oxygen gas and moisture permeability are high, making it difficult to use the cured coating for purposes such as blocking oxygen gas and preventing moisture. Therefore, in these respects, the field of application of liquid diene polymers is greatly limited. Therefore, the present inventors conducted intensive studies on liquid diene-based polymers that can solve the above-mentioned drawbacks and can be used in a wider range of fields, and as a result, they have completed the present invention. That is, the present invention comprises adding at least one ethylenically unsaturated monomer selected from the group consisting of methyl methacrylate, ethyl methacrylate, butyl methacrylate, acrylonitrile, and methacrylonitrile to a liquid diene polymer containing a terminal hydroxyl group. Production of a curable grafted liquid diene copolymer characterized by graft copolymerization and then reacting the obtained graft copolymer with a reaction product of 2,4-tolylene diisocyanate and 2-hydroxyethyl acrylate. It's a method. Here, the liquid diene polymer containing a terminal hydroxyl group is
This is the base of the resulting liquid diene copolymer. This liquid diene polymer containing terminal hydroxyl groups has an average of 1.7 to 1.7 hydroxyl groups per molecule at the terminal end of the molecule.
Examples include liquid diene polymers containing 3.0 molecules and a molecular weight of about 300 to 25,000, particularly preferably 500 to 10,000. These polymers include diene polymers having 4 to 12 carbon atoms, copolymers thereof, and copolymers of these diene monomers and α-olefinic addition polymerizable monomers having 2 to 22 carbon atoms. Specifically, butadiene homopolymer, isoprene homopolymer, chloroprene homopolymer,
Butadiene-styrene copolymer, butadiene-
Isoprene copolymer, butadiene-acrylonitrile copolymer, butadiene-2-ethylhexyl acrylate copolymer, butadiene-n-
Examples include octadecyl acrylate copolymer. On the other hand, the ethylenically unsaturated monomer may be any monomer that has an ethylenically unsaturated bond and can be graft copolymerized with an active hydrogen-containing liquid diene polymer. may include methyl methacrylate, ethyl methacrylate, butyl methacrylate, acrylonitrile and methacrylonitrile. Methods for graft copolymerizing the ethylenically unsaturated monomer to the above-mentioned liquid diene polymer containing terminal hydroxyl groups include polymerization in an aqueous medium, that is, conventional polymerization such as emulsion polymerization, suspension polymerization, bulk polymerization, and solution polymerization. Any method may be used without any particular restrictions. Generally, when the liquid diene polymer containing a terminal hydroxyl group can be mixed with or dissolved in the ethylenically unsaturated monomer, bulk polymerization is preferred. An organic solvent can be used as necessary or desired, and suitable examples include benzene, ethylbenzene, toluene, xylenes, methyl ethyl ketone, acetone, cellosolve acetate, methylene chloride, dimethylformamide and the like. The reaction in graft copolymerization is usually a terminal hydroxyl group-containing liquid diene polymer/ethylenic unsaturated monomer = 95/5 to 30/70 (weight ratio), preferably 90/10.
The process is carried out by blending in a ratio of ~60/40 (weight ratio) and setting the mixture at a temperature of 60 to 170°C under atmospheric pressure. In addition, a catalyst is usually used at this time.
Suitable catalysts are free radical generating catalysts such as peroxy or perazo catalysts. Specific examples include ditertiary butyl peroxide, benzoyl peroxide, lauroyl peroxide, t-butyl perbenzoate, isopropyl carbonate, cumene hydroxy peroxide, 2,2'-azobisisobutyronitrile, etc. Particularly preferred is benzoyl peroxide. It is possible to use various catalysts other than the above-mentioned free radical generating catalysts. When a catalyst is not used, the amount thereof is generally 0.001 to 5.0% by weight, preferably 0.05 to 2.5% by weight, based on the total weight of the terminal hydroxyl group-containing liquid diene polymer and the ethylenically unsaturated monomer to be grafted. %. Furthermore, in the graft copolymerization, it is preferable to degas oxygen, which has a copolymerization inhibiting effect, and to carry out the graft copolymerization under a nitrogen atmosphere. The obtained graft copolymer has, for example, a viscosity of 50 to 1000 poise/30° C. and an average of 1.7 to 3.0 hydroxyl groups per molecule, although this varies depending on the conditions. It is preferable to remove the solvent, dry it, and use it for the next reaction. The present invention is characterized in that the graft copolymer obtained as described above is reacted with a reaction product of 2,4-tolylene diisocyanate and 2-hydroxyethyl acrylate. Note that the reaction conditions at this time vary depending on the type of graft copolymer and the reaction product of 2,4-tolylene diisocyanate and 2-hydroxyethyl acrylate, and cannot be unambiguously determined, but usually the temperature is 0 to 200°C, Preferably, the reaction may be carried out at 10 to 120°C with stirring for 30 minutes to 12 hours, preferably 1 to 6 hours. The blending ratio of the graft copolymer and the reaction product varies depending on the type of these compounds and the desired physical properties of the intended grafted liquid diene polymer, but generally the number of moles of substituents in the reaction product is /Number of moles of hydroxyl groups in the graft copolymer=0.2 to 5.0, preferably 0.5 to 2.0. In addition,
Here, the substituent of the reaction product means a substituent that reacts with the hydroxyl group of the graft copolymer or a modified substituent thereof, such as an isocyanate group. Furthermore, in this reaction, catalysts, solvents, additives, etc. can be added as necessary or desired. As the catalyst, in the case of (1) above, commonly used esterification catalysts such as hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, and benzenesulfonic acid are used. In the case of (2), tertiary amine compounds such as trimethylamine, triethylamine, and triethylenediamine; (Lewis) acid catalysts such as boron trifluoride, zinc borofluoride, and stannic chloride are used. In the cases of (3) and (4), ordinary catalysts for urethane reactions can be used. Examples include stannides such as dibutyltin dilaurate and stannath octoate; and tertiary amine compounds such as triethylenediamine, triethylamine, N-methylmorpholine, and N,N'-diethyl-2-methylpiperazine. As a solvent, aromatic hydrocarbons such as benzene, toluene, and xylene,
Examples include (halogenated) hydrocarbons such as methylene chloride, chloroform, hexane, and heptane, tetrahydrofuran, dimethylformamide, and dimethyl sulfoxide. Additives include polymerization inhibitors such as p-benzoquinone, hydroquinone, hydroquinone monomethyl ether, nitrosophenol, dinitrophenol,
Examples include α-naphthoquinone and aminophenol. Since the grafted liquid diene copolymer obtained in this way contains a polymerizable unsaturated group internally, various polymerization initiators such as benzoin, benzoin methyl ether, benzoin butyl ether, benzophenone, etc. An appropriate amount of a photopolymerization initiator or a thermal polymerization initiator such as benzoyl peroxide, lauryl peroxide, methyl ethyl ketone peroxide, azobisisobutyronitrile, etc., specifically, 100 parts by weight of the above-mentioned grafted liquid diene copolymer. 0.5-10 for
If the composition is made by adding within the range of parts by weight and further adding auxiliary ingredients as appropriate, it may be irradiated with ultraviolet rays, etc.
A cured product can be obtained by heat treatment. The strength of the final cured product obtained here. In particular, the tensile strength and tear strength are significantly improved compared to conventional ones. Moreover, the cured film made of this cured product has low oxygen permeability and moisture permeability, and is excellent in weather resistance. Furthermore, since it has a graft chain, the reactivity of the secondary modified end and the unsaturated group of the graft chain can be adjusted by reacting it with something in which an unsaturated group has been introduced into the graft chain, such as divinylbenzene. became possible. Therefore, the liquid diene copolymer produced according to the present invention can be effectively used in a wide range of fields including paints, coatings, adhesives, and the like. Next, the present invention will be explained in detail with reference to examples. Examples 1 to 4 A predetermined amount of hydroxyl group-containing liquid polybutadiene or hydroxyl group-containing styrene-butadiene copolymer was charged into a reactor, and the reactor was purged with nitrogen while stirring.
Next, predetermined amounts of vinyl monomer, benzoyl peroxide, and toluene were added, the temperature was raised to 60°C, and the reaction was carried out under a nitrogen atmosphere with vigorous stirring for 24 hours. After cooling, the reactant was taken out and toluene and unreacted vinyl monomer were distilled off under reduced pressure to obtain a hydroxyl group-containing liquid polybutadiene-based graft copolymer.
Table 1 shows the measurement results of the viscosity and hydroxyl group content of the obtained graft copolymer. Next, a predetermined amount of the graft copolymer was charged into a reactor, dried under reduced pressure at 70°C for 30 minutes, and returned to normal pressure with dry nitrogen. To this, predetermined amounts of isocyanate group-containing prepolymer, p-benzoquinone, toluene, and dibutyltin dilaurate were added, and the reaction was carried out with stirring at 70° C. for 4 hours to obtain an acryloylated liquid polybutadiene-based graft copolymer.
The viscosity measurement results are shown in Table 1. Comparative Example 1 Acryloylated liquid polybutadiene was obtained according to Example 1 except that graft copolymerization with a vinyl monomer was not performed. The viscosity measurement results are shown in Table 1. Use Examples 1 to 4 and Comparative Use Example 1 100 parts by weight of the acryloylated liquid polybutadiene polymer obtained in Examples 1 to 4 and Comparative Example 1 (corresponding to Use Examples 1 to 4 and Comparative Use Example 1, respectively), 30 parts by weight of toluene Parts by weight and 2 parts by weight of benzoin butyl ether were mixed uniformly, poured onto a glass plate to a film thickness of approximately 0.2 mm, degassed, and then cured using an ultraviolet curing device at an intensity of 160 W/cm and a lamp distance of 10.
A cured sheet was obtained by irradiation for 10 seconds under conditions of cm. Table 2 shows the results of measuring the physical properties and transmittance of the obtained sheet. Also, the thickness of the composition treated with zinc phosphate
It was spray coated on both sides of a 50μ, 500×300mm iron foil, and cured under the same curing conditions as above to obtain an iron foil with a coating film of about 45μ. The obtained coated iron foil was plastered on the surface of the ground exposed to sunlight and an exposure test was conducted for 4 years. Table 2 shows the results of visual evaluation of the condition of the coating film and the occurrence of rust.

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Claims (1)

[Claims] 1 Graft copolymerization of at least one ethylenically unsaturated monomer selected from the group consisting of methyl methacrylate, ethyl methacrylate, butyl methacrylate, acrylonitrile, and methacrylonitrile to a liquid diene polymer containing a terminal hydroxyl group. and then reacting the obtained graft copolymer with a reaction product of 2,4-tolylene diisocyanate and 2-hydroxyethyl acrylate.