JPH0242368B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a one-component urethane resin, and more specifically, by selecting a specific polymer to which ethylene oxide is added, the present invention provides good storage stability and easy production, and also improves the physical properties of the resulting cured product. The present invention relates to a method for producing a one-component urethane resin with excellent properties. Conventionally, two-component polyurethane elastomers, which are obtained by reacting active hydrogen group-containing liquid diene polymers with polyisocyanate compounds as raw materials for urethane resins, have been used in many fields due to their excellent low-temperature properties and water resistance. used in However, this two-component reactive urethane resin has a very fast curing reaction, and can be used to form sheets using various kneading machines and molding machines, or as a modifier for asphalt for road paving, coating agents, and adhesives. In fields such as pharmaceuticals, it is not possible to take sufficient time for molding and working, which is a major drawback. To overcome these drawbacks, moisture-curable one-component urethane resins, which are isocyanate group-containing liquid diene polymers obtained by reacting active hydrogen group-containing liquid diene polymers with organic polyisocyanate compounds, are known. ing. However, one-component urethane resin prepolymers have low storage stability, and the cured products obtained by moisture curing do not have sufficient physical properties, especially elongation properties, and when used as adhesives, for example, they do not have sufficient peel strength. However, there were some drawbacks such as lack of reliability. Therefore, the present inventors have conducted extensive research into improving the physical properties of cured products of one-component urethane resins that have good storage stability and are useful as adhesives, coating agents, modifiers for asphalt, resins, etc. Among these, various studies were conducted on the effects of adding other polyols to liquid diene polymers containing active hydrogen groups. As a result, it was discovered that when using a polymer obtained by adding ethylene oxide to a polyol to which propylene oxide is added, a one-component urethane resin that eliminates the conventional drawbacks can be efficiently obtained. The present invention has been completed based on these findings. That is, the present invention comprises (A) a liquid diene polymer containing active hydrogen groups (hereinafter referred to as component (A)), (B) a polymer in which propylene oxide is added to a polyol, and 3 to 60% by weight of ethylene oxide. Addition polymer (hereinafter referred to as component (B)) and (C) organic polyisocyanate compound (hereinafter referred to as component (C))
The present invention provides a method for producing a one-component urethane resin, which is characterized by reacting the following. The active hydrogen group-containing liquid diene polymer used in the present invention as component (A) has an active hydrogen group such as a hydroxyl group, an amino group, an imino group, a carboxyl group, or a mercapto group at the molecular end and has a number average molecular weight of 300. ~
25,000, preferably 500 to 10,000. These liquid diene polymers include diene polymers having 4 to 12 carbon atoms, diene copolymers,
Furthermore, there are copolymers of these diene monomers and α-olefinic addition polymerizable monomers having 2 to 22 carbon atoms. Specific examples include butadiene homopolymer, isoprene homopolymer, butadiene-styrene copolymer, butadiene-isoprene copolymer, butadiene-acrylonitrile copolymer, butadiene-2-ethylhexyl acrylate copolymer, butadiene-n-octadecyl acrylate copolymer, and the like. These liquid diene polymers can be produced, for example, by subjecting a conjugated diene monomer to a heating reaction in the presence of hydrogen peroxide in a liquid reaction medium. The liquid diene polymer thus obtained contains an average of 1.7 to 3.0 hydroxyl groups as functional groups. The fine structure of these liquid diene polymers is not particularly limited, but when flexibility is desired, those having 50% or more of 1,4 bonds are used. Next, component (B) is a polymer obtained by adding 3 to 60% by weight of ethylene oxide to a polymer obtained by adding propylene oxide to a polyol. Here, polyol is a diol, triol, or a compound having four or more hydroxyl groups, such as ethylene glycol, 1,2-propylene glycol,
Examples include 1,3-propylene glycol, glycerin, diglycerin, and Cordroll (trade name). Propylene oxide is added to this polyol to form a polymer. The amount of propylene oxide used is preferably such that the proportion of propylene oxide units in the polymer is 90 to 99% by weight. Therefore, this polymer is obtained by addition polymerizing a large amount of propylene oxide to a polyol such as ethylene glycol or propylene glycol, and basically belongs to polypropylene glycol. Component (B) is obtained by further adding 3 to 60% by weight, preferably 5 to 45% by weight of the polymer from which ethylene oxide can be obtained. The reason why ethylene oxide is used as component (B) is that by adding an appropriate amount of ethylene oxide, the primaryization rate of hydroxyl groups in the polymer obtained by adding propylene oxide to polyol is improved, and the component (A) This is to make the reactivity comparable to that of active hydrogen groups such as hydroxyl groups therein. By setting the reactivity to the same level, the reactivity of component (A) and component (B) with respect to isocyanate can be made uniform, and storage stability and moisture curability can be improved. Here, if the amount of ethylene oxide added is less than 3% by weight, the effect of the addition is not sufficient, and if it exceeds 60% by weight, it becomes waxy and difficult to handle, which is not preferable. The number average molecular weight of component (B) is usually 300 to 15,000, preferably 500 to 8,000. The amount of component (B) to be used is not particularly limited and is determined appropriately taking into account the purpose of use of the one-component urethane resin, the target physical properties, the molecular weight of component (A), etc., but usually the amount of component (A) / (B) Component = 98-2/2-98 (weight ratio),
It is preferably used in a range of 95-5/5-95 (weight ratio). If the value of component (A)/component (B) exceeds 98/2, the storage stability and cured physical properties will be poor, and if it is less than 2/98, the rubber elasticity, adhesive strength to rubber, water resistance, etc. will be poor, which is not preferable. Furthermore, as the organic polyisocyanate compound which is the component (C) which reacts with the active hydrogen groups of the components (A) and (B) to form a urethane resin, examples include diphenylmethane diisocyanate (MDI), crude
MDI, tolylene diisocyanate, liquid modified product of diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, cyclohexane phenylene diisocyanate, chlorophenylene diisocyanate, naphthalene-1,5-diisocyanate, xylylene-2,2'-diisocyanate, Isopropylbenzene-2,4-diisocyanate, polymethylene polyphenyl isocyanate, triphenylmethane triisocyanate, isophorone diisocyanate, polypropylene glycol or triol and tolylene diisocyanate addition reaction product, addition of 1 mole of trimethylolpropane and 3 moles of tolylene diisocyanate Examples include reactants. MDI is particularly suitable. The reaction to obtain the one-component urethane resin of the present invention is usually
The reaction is carried out at an NCO/active hydrogen group (equivalence ratio) of 1.6 or more, preferably 2.0 or more, under an inert atmosphere such as dry nitrogen, at a reaction temperature of 10 to 150°C, and a reaction time of 0.5 to 10 hours. If the equivalent ratio of the organic polyisocyanate compound is small, chain extension occurs due to the urethane reaction, which increases the molecular weight and increases the viscosity, which is undesirable.On the other hand, if it is too large, the organic polyisocyanate compound monomer remains, making it safe to use. Undesirable in terms of sex. In the present invention, a one-component urethane resin can be produced by reacting the above components (A), (B), and (C), but if necessary, various additives such as plasticizers may be used. can. The plasticizer used here is not particularly limited and various types can be used, including phthalic acid esters such as dibutyl phthalate, di-2-ethylhexyl phthalate, and di-n-octyl phthalate, dioctyl adipate, and dioctyl azelate. , linear dibasic acid esters such as dioctyl sebacate, phosphoric acid esters such as tri-2-ethylhexyl phosphate, cresyl phosphate, tricylenyl phosphate, naphthenic oils, aromatic oils, alkyl aromatic oils Examples include oils such as oil. The plasticizer used here may be selected appropriately depending on the use of the one-component urethane resin, taking into consideration heat resistance, cold resistance, chemical resistance, electrical properties, compatibility with other raw materials, etc. . The amount of plasticizer used here is not particularly limited, and is 0 to 70% by weight, preferably 20 to 70% by weight based on the one-component urethane resin.
It may be determined as appropriate within the range of 50% by weight, taking into consideration workability, usage, etc. In addition, tertiary amines, metal salts, and organometallic compounds may be used as catalysts. Furthermore, a solvent containing no active hydrogen group can also be used as the solvent. The one-component urethane resin obtained as described above has extremely good prepolymer storage stability and can maintain the physical properties at the time of manufacture for a long period of time. In particular, the viscosity of the prepolymer can be suppressed to be lower than that of conventional prepolymers, and large amounts of various fillers can be blended, making it possible to obtain inexpensive cured products.
In addition, they have excellent workability and can be easily applied alone or mixed with various solvents using spray guns, brushes, roll coaters, flow coaters, etc. A cured film is then obtained. Therefore,
It can be suitably used for coating waterproofing materials, paints, anticorrosive coatings, and breakage and shatterproof coatings for glass bottles, glass windows, and the like. The resulting coating has excellent physical properties, especially mechanical properties such as tensile strength, tensile elongation, and impact strength. In addition, one-component urethane resin is not limited to use as a coating material.
It can be used in a wide variety of applications, including as a modifier for asphalt and water-soluble resins, as a molding agent for sheets, and as an impregnating agent for porous materials such as textile products. Next, the present invention will be explained in more detail with reference to Examples. Examples 1 and 2 and Comparative Examples 1 and 2 A liquid diene polymer, polypropylene glycol added with ethylene oxide, and dioctyl phthalate were introduced in the amounts shown in Table 1 into a 2-volume separable flask, and the mixture was heated at 80°C and 1 mmHg for 1 hour. The mixture was heated and stirred for hours. Then cool to room temperature and 80°C at room temperature.
The amount of 4,4'-diphenylmethane diisocyanate (MDI) melted at 0.degree. C. as shown in Table 1 was added with vigorous stirring, and the mixture was kept at room temperature for about 1 hour. Next, the mixture was heated and stirred at 80° C. for 3 hours to cause a sufficient reaction and obtain a prepolymer. The prepolymer was stored in one can, and the viscosity immediately after synthesis and one month later was measured. Moisture-cured physical properties were determined by applying the prepolymer to a thickness of 2 mm on a glass plate to obtain a cured product.

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Claims (1)

[Scope of Claims] 1 (A) a liquid diene polymer containing active hydrogen groups, (B) a polymer obtained by adding 3 to 60% by weight of ethylene oxide to a polymer obtained by adding propylene oxide to a polyol, and ( C) A method for producing a one-component urethane resin, which is characterized by reacting an organic polyisocyanate compound. 2 The polyol is ethylene glycol, 1,2-
The manufacturing method according to claim 1, which is any one of propylene glycol, 1,3-propylene glycol, glycerin, and diglycerin.