JPS6317084B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing water-curing elastomers. More specifically, when a composition whose main component is a prepolymer having an isocyanate group at the molecular end (hereinafter referred to as the main component) is cured with a curing composition containing water (hereinafter referred to as the curing agent), water separates during storage. The present invention relates to a method for producing a water-cured elastomer from a curing agent that does not contain a curing agent. The water-curing elastomer produced by the method of the present invention can be used as a general elastomer, waterproofing material, sealing material, flooring material,
Suitable for uses such as grounding material and coating material. Conventionally, methods of curing urethane prepolymers using water as an active hydrogen compound have been known. When a urethane prepolymer is cured with a curing agent containing water, carbon dioxide gas is generated and foaming occurs, which is not preferable as an elastomer. As a way to prevent this foaming, the curing agent contains the second element in the periodic table of elements.
Using hydroxides, oxides, basic salts, complex salts, double salts, etc. of metals belonging to Groups 3 and 4, fillers, organic liquids, catalysts, stabilizers, pigments, etc. are mixed and homogenized as necessary. It is possible to produce non-foamed urethane elastomers (for example, Japanese Patent Publication No. 43-14237).
Such). However, these curing agents had the disadvantage of water separation during storage. As a method for improving this, it has been shown in JP-A-53-111395 that the use of nonionic surfactants is effective. However, with this method, when construction is carried out in the summer,
The temperature of the curing agent can rise to around 40℃,
Long periods of time at such temperatures or high temperatures (approximately 50°C)
Separation of water is unavoidable during storage in
I can't say it's satisfactory. As a result of studying this point, it has been found that the above-mentioned drawbacks can be improved by using a nonionic surfactant and an ionic surfactant in combination. In addition, in order to produce a product that is stable for a relatively long period of time by adding each of these surfactants to the curing agent alone, 2 parts or more should be added to 100 parts by weight of the curing agent (the following parts indicate parts by weight). However, it was discovered that when nonionic and ionic surfactants are used in combination, satisfactory results can be obtained even with an addition amount of 1 part or less, and the durability of the resulting elastomer is also good. , arrived at the present invention. That is, when curing a composition mainly composed of a prepolymer having an isocyanate group at the molecular end with a curing composition containing water, the present invention provides a method for adding a nonionic surfactant and an ionic surfactant to the curing composition. is used in combination, and the total amount of the surfactant added is 0.5
1% by weight. In this case, the mixing ratio of the nonionic surfactant and the ionic surfactant can be appropriately selected depending on the purpose, and is usually 30:70 to 70:30 (weight ratio). Outside this range, storage stability for long periods of time or at high temperatures tends to deteriorate. Nonionic surfactants used in the present invention include polyoxyethylene alkyl ethers, polyoxyethylene fatty acid esters, polyoxyethylene alkyl phenyl ethers, sorbitan aliphatic esters also called span-type surfactants, and polyoxyethylene sorbitan fatty acid esters. and so on. The ionic surfactants used in the present invention can be broadly classified into anionic, cationic, and amphoteric surfactants. Examples of anionic salts include fatty acid salts such as rosin acid soap, sulfate esters such as castor oil, lauryl alcohol, sulfuric esters of higher alcohols, and sulfonates such as sodium sulfonates or amine salts such as alkylaryl and alkylnaphthalene. , phosphoric acid ester types such as alkylphenol, alkyl phosphoric acid esters, etc. are used. As the cation type, quaternary ammonium salts such as ammonium chloride or bromide such as lauryldimethylbenzyl and alkyltrimethyl are used, and amine salts include aliphatic amine salts, imidazoline derivatives, etc. As the zwitterion type, amino acid type such as dodecyl polyaminoethylglycine, polyoctyl polyaminoethylglycine, etc., betaine type such as alkyl dimethyl betaine, imidazoline type, etc. are used. The amount of surfactant (nonionic + ionic) used is 0.5 to 1 part per 100 parts of curing agent. If the amount is less than 0.5 parts, the intended purpose will not be achieved, and if it exceeds 2 parts, the surfactant will not only bleed onto the surface of the curing agent and reduce the commercial value, but also bleed onto the surface of the urethane elastomer after curing. This is undesirable because it causes harmful effects such as a significant decrease in water resistance. The main ingredient is an active hydrogen-containing compound and an organic polyisocyanate, usually with an NCO/OH (equivalent ratio) of 1.5 or more, and 40
It is obtained by reacting at ~150°C, preferably 50~100°C, and has terminal isocyanate groups of 1~20% by weight (hereinafter % indicates weight%), preferably 2~9%. Such active hydrogen-containing compounds include polyether polyols and polyester polyols. Examples of polyether polyols include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, dipropylene glycol, trimethylene glycol,
1,4 or 1,3-butylene glycol, tetramethylene glycol, neopentyl glycol,
Hexamethylene glycol, decamethylene glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, sucrose, aconitic acid, trimellitic acid, hemimellitic acid, ethylenediamine, propylene diamine, diethylenetriamine, triethanolamine, pyrogallol, dihydrobenzoic acid, hydroxyphthal Acid, resorcinol, hydroquinone, bisphenol A (2,2-bis(4'-hydroxyphenyl)
ethylene oxide, bisphenol F (4,4'-dihydroxydiphenylmethane), 1,2-propanedithiol, etc. An addition polymer obtained by adding one or more of propylene oxide, butylene oxide, tetrahydrofuran, styrene oxide, etc., and a polyether having a molecular weight of 100 to 10,000, preferably 300 to 5,000, is used. Examples of polyester polyols include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, dipropylene glycol, trimethylene glycol, 1,4 or 1,3-butylene glycol, tetramethylene glycol, neopentyl glycol, hexamethylene One or more compounds having at least two hydroxyl groups in the molecule, such as glycol, decamethylene glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, etc., and malonic acid, maleic acid, succinic acid, adipine. acids, compounds having at least two carboxyl groups in the molecule, such as tartaric acid, pimelic acid, sebacic acid, oxalic acid, phthalic acid, terephthalic acid, hexahydrophthalic acid, aconitic acid, trimellitic acid, hemimellitic acid, etc. A condensation polymer of one type or two or more types is used. In addition, active hydrogen-containing compounds include ring-opening polymers of cyclic esters such as polycaprolactone, and furthermore, ethylenically unsaturated monomers or polymers of the monomers in polyether polyols in the presence of a radical initiator. Polymer polyl obtained by graft polymerization, 1,2-polybutadiene glycol, 1,
Compounds such as 4-polybutadiene glycol may also be used. The above-mentioned polyether polyols, polyester polyols, and other active hydrogen compounds can be used alone or as a mixture of two or more. As the organic polyisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, a mixture of 2,4 and 2,6-tolylene diisocyanate (65/35, 80/20), 4,4'-
Diphenylmethane diisocyanate, m-phenylene diisocyanate, xylylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate ester, 1,4-cyclohexylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 3,3'-dimethyl -4,4'-biphenylene diisocyanate, 3,3'-dimethoxy-4,4'-biphenylene diisocyanate,
3,3'-dichloro-4,4'-biphenylene diisocyanate, 1,5-naphthalene diisocyanate, 1,5-tetrahydronaphthalene diisocyanate, etc. are used. Crude products of tolylene diisocyanate and 4,4'-diphenylmethane diisocyanate and modified products such as carbodiimide-modified 4,4'-diphenylmethane diisocyanate can also be used. The above organic polyisocyanates may be used alone or as a mixture of two or more. The main ingredient may be a prepolymer alone or may contain a solvent or plasticizer as a thinning agent. The amount of thinner used is 40% or less of the base agent. Water is used as a crosslinking agent in the curing agent, and the amount thereof is 3 to 50%, preferably 5 to 30% in the curing agent. Moreover, a polyamine and/or a polyol can also be used in combination. Examples of polyamines include ethylenediamine,
Hexamethylene diamine, piperazine, p-xylene diamine, p-phenylene diamine, 1,4
-Diaminocyclohexane, 4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-diethyl-
4,4'-diaminodiphenylmethane, 3,3'-dichloro-4,4'-diaminodiphenylmethane,
4,4'-diaminodiphenyl ether, 4,4'-
Ester of methylene dianthranilic acid (dimethyl form, diethyl form, diisopropyl form), etc. are used. As the polyol in the curing agent, the polyols exemplified in the section of the main ingredient are used. The base resin and the curing agent are reacted at an isocyanate group/active hydrogen (equivalence ratio) of 0.005 to 2.0, preferably 0.02 to 1.5. The carbon dioxide absorbent used in the curing agent in the present invention is a hydroxide or oxide of a metal belonging to Groups 2, 3, or 4 of the Periodic Table of Elements, or basic salts, complex salts, or double salts, etc. Basic metal hydroxides such as calcium hydroxide, barium hydroxide, and magnesium hydroxide, metal oxides such as quicklime and barium oxide, and cements such as Portland cement can be used. It is also possible to use these in combination. These carbon dioxide absorbers account for 5 to 50%, preferably 10 to 30%, of the curing agent. The fillers used in the present invention include conventionally known fillers such as calcium carbonate, talc, clay, silica, carbon black, and titanium oxide, and the amount of fillers used is 0 to 55% of the hardening agent. Organic liquids include coal tar, dioctyl phthalate, dibutyl phthalate, dioctyl adipate, chlorinated paraffin, tricresyl phosphate, trioctyl phosphate, and liquefied low polymers of terpene resins (Eurex, Tokyo Jushi Co., Ltd.) ) etc. The amount of organic liquid used is 20% to 60% of the curing agent.) The catalyst used in the present invention is a known catalyst that promotes the urethanization reaction or the urea production reaction, such as triethylenediamine. amines such as lead acetate, lead caproate, lead octylate, lead caprate, lead salts of organic acids such as lead naphthenate, and tin such as dibutyltin dilaurate, dibutyltin di-2-ethylhexoate, etc. A compound is used. These catalysts may be used alone or in combination. Other additives that may be used include antifoaming agents, ultraviolet absorbers, antioxidants, and pigments, if necessary. These curing agents are produced by kneading and dispersing them using a kneader, a sieve, a roll, a sand mill, etc., which are capable of sufficiently uniform mixing. Next, production examples and comparative examples are shown in Table 1, but the present invention is not limited only to these production examples. Comparative Examples 1 to 10, Production Examples 1 to 4 32 parts of coal tar, 15 parts of dioctyl phthalate
part, slaked lime 10 parts, calcium carbonate 28 parts, talc 5 parts
part, 10 parts of water and surfactant (A to F) shown in Table 1.
was added and thoroughly mixed and dispersed at room temperature using a stirrer. Place this mixture in an oven at 50℃ for 7
The state of water dispersion was observed after several days.

[Table] From Table 1, it is clear that by using a nonionic surfactant and an ionic surfactant together, water separation does not occur in a smaller amount than when these surfactants are used alone. be. Example 1 The curing agent of Production Example 1 was used as the main ingredient [Hyprene p302,
Manufactured by Mitsui Nisso Urethane Co., Ltd. NCO% = 3.2%, viscosity 9000
centipoise (25°C)] at a ratio of 1:1 (weight ratio), and after curing a sheet of approximately 2 mm thick at 20°C for 7 days, the physical properties of the coating film were: hardness (Shore A): 43, tensile strength: 42
Kg/cm ² , elongation 800% (dumbbell size 3), tear strength 16
Kg/cm (tear type B). Furthermore, 20 test pieces (dumbbell size 3, tear type B) punched out from the coating film after curing for 7 days were
The physical properties after being immersed in water for 10 days at ℃ were as follows: hardness (Shor A): 42, tensile strength: 40 Kg/cm ² , elongation: 850%, and tear strength: 16 Kg/cm. The physical properties of the coating film were measured in accordance with JISK6301. Comparative Example 11 A sheet with a thickness of about 2 mm was prepared in the same manner as in Example 1, except that the curing agent produced in Comparative Example 3 was used. The obtained sheet was tested in the same manner as in Example 1. Paint film hardness after curing for 7 days at 20℃ (Short A)
was 43, the tensile strength was 41 Kg/cm ² , the elongation was 820%, and the tear strength was 16 Kg/cm, which were almost the same as in Example 1. The above physical properties after immersion in water for 10 days at 20℃ are 39, 31Kg/cm ² , 930%, and 12Kg/cm 2 , respectively.
cm, and the strength decreased significantly. Comparative Example 12 A sheet with a thickness of about 2 mm was prepared in the same manner as in Example 1, except that the curing agent produced in Comparative Example 6 was used. The obtained sheet was tested in the same manner as in Example 1. Paint film hardness after curing for 7 days at 20℃ (Short A)
was 43, the tensile strength was 42 Kg/cm ² , the elongation was 790%, and the tear strength was 16 Kg/cm, which were almost the same as in Example 1. The above physical properties after immersion in water for 10 days at 20℃ are 38, 30Kg/ ^cm2 , 920%, and 12Kg/cm2, respectively.
cm, and the strength decreased significantly.

Claims (1)

[Claims] 1. When curing a composition whose main component is a prepolymer having an isocyanate group at the molecular end with a curing composition containing water, a nonionic surfactant and an ionic surfactant are used in combination in the curing composition. A method for producing a water-curing elastomer, characterized in that the total amount of the surfactant added is 0.5 to 1% by weight.