JP2001064505A - Plasticizer for sealing material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasticizer for a urethane sealing material having an isocyanate group at a molecular chain terminal, good in plasticity, and giving little heat loss and migration, by using a urethane polyether. SOLUTION: This urethane polyether is represented by the formula (wherein R1 is a residual group of an m-valent isocyanate whose isocyanate group is removed; R2 and R3 are each a hydrocarbon group; and (m) and (n) are each a positive integer) and its mol.wt. is pref. 300-30,000, and residual amount of isocyanate group is pref. 0.5-5 wt.%. Manufacturing method is not specifically restricted, but an alkylene oxide is attached in the presence of a catalyst such as sodium hydroxide to alcohol or phenol to be a base of polyalkylene glycol monoether, as a precursor. An m-valent isocyanate is reacted with the obtd. polyalkylene glycol monoether without a catalyst or in the presence of a urethanization catalyst. Compounding amount of a plasticizer is 1-100 wt.% to a sealing substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasticizer for a urethane sealant having a terminal isocyanate group.

[0002]

2. Description of the Related Art Various sealing materials are used for filling and sealing joints and cracks for the purpose of watertightness and airtightness. These sealants are used in a daily place such as a home kitchen or a bath. It is used in a wide range of fields such as industrial products such as automobiles and ships, and large-scale buildings such as bridges and tunnels. As these sealants, silicone-based sealants, water-swellable urethane-based sealants, oxygen-curable polysulfide-based sealants, and the like have been developed. Among these, as the urethane-based sealing material, there are a one-component type that cures with moisture in the atmosphere, a two-component type that cures by mixing with a curing agent, and a thermosetting type that cures by heating. In these sealing materials, a plasticizer or a diluent is used for the purpose of improving workability at the time of application and adjusting the elasticity of the obtained cured product. Conventionally widely used plasticizers for sealing materials are ester plasticizers such as dioctyl phthalate and dioctyl adipate, and chlorinated paraffins. However, these conventional plasticizers are disadvantageous in that heating loss is large and migration is large, so that they easily migrate to the surface, causing sticking to the surface, and dust being easily adhered to the adhesion and easily causing contamination. was there. In recent years, it has been pointed out that phthalic acid esters have a problem in safety for the human body.

[0003] In Japanese Patent Application Laid-Open No. 2-142850, a polyoxyalkylene monoether is used as a plasticizer for a sealing material instead of a phthalic acid ester to solve such a problem. Others,
No. 56590 uses polyetheresters as plasticizers or diluents for polyurethane elastomeric polymers for sealant applications. In JP-A-55-31874, a polymer compound such as polyester is used as a plasticizer for a silicone-based sealing material. JP-A-7-2
In Japanese Patent No. 28861, polyoxyalkylene monoether is used as a plasticizer for a modified polysulfide polymer that is an oxygen-curable sealing agent.

[0004]

However, it has been found that each of these newly proposed plasticizers to replace phthalates has its own drawbacks. That is,
Although high-molecular compounds such as polyesters have small heat loss, they have poor plasticity due to too small migration properties, and are difficult to handle due to their high viscosity. Esters such as polyetheresters have insufficient plasticity and may be hydrolyzed, and may generate rust when used in places where the sealing material may come into contact with metal. is there. Polyether monols have large heat loss and poor plasticity. Accordingly, an object of the present invention is to provide a plasticizer for a sealing material which is excellent in plasticity, of course, has a small heat loss and a small migration property, particularly for a urethane-based sealing material having an isocyanate group at a terminal. It is in. As a result of intensive studies, the present inventors have found that a polyether having a specific structure has better plasticity and less heat loss than a conventional polyether-based plasticizer, and has completed the present invention.

[0005]

That is, the present invention provides the following general formula (1):

[0006]

Embedded image

(Wherein, R ¹ represents a residue obtained by removing an isocyanate group from an m-valent isocyanate, R ² and R ³ represent a hydrocarbon group, m represents a number of 1 or more, and n represents 1 or more.
Represents the above numbers. ) Is a plasticizer for a urethane-based sealing material having an isocyanate group at the terminal, comprising a urethane polyether represented by the formula (1).

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is a plasticizer for a sealing material suitable for use in a urethane-based sealing material having an isocyanate group at the terminal, among the various sealing materials, and has the general formula (1) Is a plasticizer for a urethane-based sealing material comprising a urethane-based polyether obtained by reacting a mono- or polyisocyanate represented by the following formula with a polyalkylene glycol monoether. Incidentally, the plasticizer for the sealing material may be called a diluent, but these are naturally included in the present invention.

In the general formula (1), R ¹ represents a residue obtained by removing an isocyanate group from an m-valent monoisocyanate or polyisocyanate. Examples of the polyisocyanate include aliphatic diisocyanate, aromatic diisocyanate, alicyclic diisocyanate, biphenyl diisocyanate, and diisocyanate of phenylmethane derivative. Here, m represents the number of isocyanate groups, and is 1 or more. Examples of the monoisocyanate include methyl isocyanate, ethyl isocyanate, propyl isocyanate, butyl isocyanate, hexyl isocyanate, octyl isocyanate, lauryl isocyanate, octadecyl isocyanate, cyclohexyl isocyanate, phenyl isocyanate, and tolylene isocyanate.

As the aliphatic diisocyanate, for example,
Methylene diisocyanate, dimethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, dipropyl ether diisocyanate, 2,2-dimethylpentane diisocyanate, 3-methoxyhexane diisocyanate, octamethylene diisocyanate, 2,2 4-trimethylpentane diisocyanate, nonamethylene diisocyanate, decamethylene diisocyanate, 3-butoxyhexane diisocyanate, 1,4-butylene glycol dipropyl ether diisocyanate, thiodihexyl diisocyanate, meta-xylylene diisocyanate,
Paraxylylene diisocyanate, tetramethyl xylylene diisocyanate and the like can be mentioned.

As the aromatic diisocyanate, for example,
Metaphenylene diisocyanate, paraphenylene diisocyanate, 2,4-tolylene diisocyanate,
2,6-tolylene diisocyanate, dimethylbenzene diisocyanate, ethylbenzene diisocyanate,
Isopropylbenzene diisocyanate, tolidine diisocyanate, 1,4-naphthalenediisocyanate,
Examples thereof include 1,5-naphthalene diisocyanate, 1,5-tetrahydronaphthalene diisocyanate, 2,6-naphthalene diisocyanate, and 2,7-naphthalene diisocyanate.

As the alicyclic diisocyanate, for example,
Examples thereof include 1,4-cyclohexylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, cyclohexylmethane diisocyanate, methylcyclohexane diisocyanate, and dimer acid diisocyanate. As biphenyl diisocyanate, for example, biphenyl diisocyanate, 3,3 ′
-Dimethylbiphenyl diisocyanate, 3,3'-dimethoxy-4,4-biphenylenediisocyanate, and the like.

Examples of the diisocyanate of the phenylmethane derivative include diphenylmethane-4,4'-diisocyanate and 2,2'-dimethyldiphenylmethane-
4,4'-diisocyanate, diphenyldimethylmethane-4,4'-diisocyanate, 2,5,2 ', 5'
-Tetramethyldiphenylmethane-4,4'-diisocyanate, cyclohexylbis (4-isocyantophenyl) methane, 3,3'-dimethoxydiphenylmethane-4,4'-diisocyanate, 4,4'-dimethoxydiphenylmethane-3,3 ' -Diisocyanate, 4,
4′-diethoxydiphenylmethane-3,3′-diisocyanate, 2,2′-dimethyl-5,5′-dimethoxydiphenylmethane-4,4′-diisocyanate,
3,3'-dichlorodiphenyldimethylmethane-4,
4'-diisocyanate, benzophenone-3,3'-
Diisocyanate, dicyclohexylmethane-4,4 '
-Diisocyanate and the like.

As the triisocyanate, for example, 1
-Methylbenzene-2,4,6-triisocyanate,
1,3,5-trimethylbenzene-2,4,6-triisocyanate, 1,3,7-naphthalene triisocyanate, biphenyl-2,4,4'-triisocyanate, diphenylmethane-2,4,4'-triisocyanate Isocyanate, 3-methyldiphenylmethane 4,6,4'-triisocyanate, triphenylmethane-4,4 ', 4 "
-Triisocyanate, 1,6,11-undecane triisocyanate, 1,8-diisocyanate-4-isocyanatomethyloctane, 1,3,6-hexamethylene triisocyanate, bicycloheptane triisocyanate, tris (isocyanate phenyl) thiophosphate and the like Is mentioned.

Among them, monoisocyanate, hexamethylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene diisocyanate, diphenylmethane-isocyanate
Preferred are diisocyanates such as 4,4'-diisocyanate, 2,2'-dimethyldiphenylmethane-4,4'-diisocyanate, dicyclohexylmethane-4,4'-diisocyanate. These polyisocyanate compounds may be used as a dimer or a trimer (isocyanurate bond), or may be reacted with an amine and used as a biuret. Further, urethane polyisocyanate obtained by reacting a polyisocyanate with a polyol such as (poly) alkylene glycol or (poly) glycerin can also be used. Examples of such a urethane polyisocyanate include a glycerin-tolylene diisocyanate reactant and a glycerin-hexamethylene diisocyanate reactant.

In the general formula (1), R ² represents a hydrocarbon group, preferably an alkylene group having 2 to 4 carbon atoms, and more preferably a propylene group. The part of (R ² —O) _{n in} the general formula (1) is an alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran (1,4-butylene oxide), long-chain α-olefin oxide, and styrene oxide. Can be obtained by addition polymerization. When the (R ² —O) _n portion is formed by adding an alkylene oxide or the like, R ² is determined by the type of the alkylene oxide or the like to be added.

Polymerization of alkylene oxide and the like to be added
The form is not particularly limited, and one kind of alkylene oxide
Such as homopolymerization, two or more kinds of alkylene oxide
Random copolymer, block copolymer or random / block
Copolymerization or the like. R ^TwoIs a propylene group
Most preferably, R^TwoIf is more than one group
Preferably at least one of them is a propylene group
No. (R^Two-O)_nIs preferably an oxypropyl
50-100 mol%, more preferably 60-10 mol%
When the polyoxyalkylene chain contains 0 mol%,
The viscosity of the urethane polyether itself represented by the general formula (1)
Degree decreases, handling improves, and plasticity
Is also excellent. The polymerization degree n is a number of 1 or more, preferably 1
~ 200, more preferably 2-100, even more preferably
2 to 50.

In the general formula (1), R ³ represents a hydrocarbon group. Examples of the hydrocarbon group include an alkyl group, an alkenyl group, an aryl group, a cycloalkyl group, a cycloalkenyl group, and the like. Examples of the alkyl group include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, secondary butyl, tertiary butyl, pentyl, isopentyl, secondary pentyl, neopentyl, tertiary pentyl, hexyl, secondary hexyl, heptyl, and secondary Heptyl, octyl, 2-ethylhexyl, 2
Primary octyl, nonyl, secondary nonyl, decyl, secondary decyl, undecyl, secondary undecyl, dodecyl, secondary dodecyl, tridecyl, isotridecyl, secondary tridecyl,
Tetradecyl, secondary tetradecyl, hexadecyl, secondary hexadecyl, stearyl, icosyl, docosyl, tetracosyl, triacontyl, 2-butyloctyl, 2-
Butyldecyl, 2-hexyloctyl, 2-hexyldecyl, 2-octyldecyl, 2-hexyldecyl, 2
-Octyldodecyl, 2-decyltetradecyl, 2-dodecylhexadecyl, 2-hexadecyloctadecyl,
2-tetradecyloctadecyl; monomethyl-branched-isostearyl and the like.

Examples of the alkenyl group include vinyl, allyl, propenyl, butenyl, isobutenyl, pentenyl, isopentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tetradecenyl, oleyl and the like. Examples of the aryl group include phenyl, toluyl, xylyl,
Cumenyl, mesityl, benzyl, phenethyl, styryl, cinnamyl, benzhydryl, trityl, ethylphenyl, propylphenyl, butylphenyl, pentylphenyl, hexylphenyl, heptylphenyl, octylphenyl, nonylphenyl, decylphenyl, undecylphenyl, dodecylphenyl, Examples include phenylphenyl, benzylphenyl, styrenated phenyl, p-cumylphenyl, α-naphthyl, and β-naphthyl groups.

Examples of the cycloalkyl group and cycloalkenyl group include, for example, cyclopentyl, cyclohexyl, cycloheptyl, methylcyclopentyl, methylcyclohexyl, methylcycloheptyl, cyclopentenyl, cyclohexenyl, cycloheptenyl, methylcyclopentenyl, methylcyclohexenyl, methylcyclohepenyl And a thenyl group. Among these, an alkenyl group such as an allyl group is preferably an alkyl group because it may have poor thermal stability or oxidative stability.

The molecular weight of the urethane polyether represented by the general formula (1) is not particularly limited. However, if the molecular weight is too small, the migration property is too large and bleed out from the base material of the sealing material is easy. On the other hand, if the molecular weight is too large. Due to poor miscibility with the sealing material substrate, 300-
30,000 is preferable, and 500 to 10,000 is more preferable.

The method for producing the urethane polyether represented by the general formula (1) is not particularly limited. Usually, first,
In the presence of a catalyst such as sodium hydroxide, potassium hydroxide, cesium hydroxide, sodium methoxide, trimethylamine, sulfuric acid, trifluoroborate etherate, to the alcohol or phenol serving as the base of the precursor polyalkylene glycol monoether, Addition of alkylene oxide gives polyalkylene glycol monoether. At this time, when the polyalkylene glycol is by-produced, not only does the plasticity of the final product, urethane polyether, decrease, but also the viscosity of the urethane polyether itself increases. Alcohol or phenol,
It is preferable to remove moisture in the catalyst. Then
The urethane-forming reaction between the polyalkylene glycol monoether and the m-valent isocyanate is preferably performed at 50 to 120 ° C. in the absence of a catalyst or in the presence of a urethanizing catalyst such as dibutyltin oxide. The reaction ratio between the two is preferably about 0.9 to 1.0 equivalent of isocyanate group based on the hydroxyl equivalent of polyalkylene glycol monoether.

The amount of the plasticizer for the sealing material of the present invention represented by the general formula (1) is not particularly limited, but is preferably 1 to 100% by weight based on the sealing material base material.
It is more preferably from 80 to 80% by weight, most preferably from 10 to 70% by weight. The plasticizer for a sealing material of the present invention represented by the general formula (1) is thermally stable because the hydroxyl group at the terminal of the structure is etherified, and thus has a small heat loss.
Unlike an ester plasticizer, it does not deteriorate due to hydrolysis. Also, compared to the conventional polyether-based plasticizer, the hydroxyl group at the structural end is etherified, so that the plasticity is excellent. In particular, since the plasticizer of the present invention has a urethane group, it is excellent in miscibility with a urethane-based sealing material having an isocyanate group at a terminal. Therefore,
For a urethane-based sealing material having an isocyanate group at the terminal, if a sealing material is prepared using the plasticizer for the sealing material of the present invention, the above-described excellent properties are obtained as compared with the case where a conventional plasticizer is used. The effect can be obtained.

The plasticizer for a sealing material of the present invention is used by being compounded with a urethane-based sealing material having an isocyanate group at a terminal. The urethane-based sealing material having an isocyanate group at the terminal is composed of a urethane prepolymer produced in excess of polyisocyanate so that the isocyanate group remains. Usually, the residual amount of the isocyanate group is preferably about 0.5 to 5% by weight. The urethane prepolymer is obtained by reacting a polyisocyanate with a polyol such as a polyol, a polyether polyol, or a polyester polyol. Examples of the polyisocyanate include the above-mentioned polyisocyanates.

Examples of the polyol include ethylene glycol, propylene glycol, 1,4-butanediol, 1,2-butanediol, neopentyl glycol, 1,6-hexanediol, 1,2-octanediol, and 1,8-octanediol. Octanediol, isoprene glycol, 3-methyl-1,5-pentanediol, 1,4-
Diols such as cyclohexanedimethanol, thiodiglycol, sorbite, catechol, resorcinol, hydroquinone, bisphenol A, bisphenol F, hydrogenated bisphenol A, hydrogenated bisphenol F, and dimer diol; glycerin, trioxyisobutane, 1,2,3
-Butanetriol, 1,2,3-pentanetriol, 2-methyl-1,2,3-propanetriol, 2
-Methyl-2,3,4-butanetriol, 2-ethyl-1,2,3-butanetriol, 2,3,4-pentanetriol, 2,3,4-hexanetriol, 4-
Propyl-3,4,5-heptanetriol, 2,4-
Trihydric alcohols such as dimethyl-2,3,4-pentanetriol, pentamethylglycerin, pentaglycerin, 1,2,4-butanetriol, 1,2,4-pentanetriol, trimethylolethane, and trimethylolpropane; Erythritol, erythritol,
1,2,3,4-pentane tetrol, 2,3,4,5
Tetrahydric alcohols such as hexane tetrol, 1,2,4,5-pentane tetrol, 1,3,4,5-hexane tetrol, diglycerin and sorbitan; 5 such as adonitol, arabitol, xylitol and triglycerin And polyhydric alcohols; hexahydric alcohols such as dipentaerythritol, sorbitol, mannitol, iditol, inositol, daritol, talose, and allose; octahydric alcohols such as sucrose, and polyglycerin.

Examples of the polyether polyol include those obtained by adding an alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide, or tetrahydrofuran to the above polyol. When the urethane prepolymer thus obtained is used as a one-component curable sealing material, the urethane prepolymer is cured by moisture in the air and the like, and thus does not require a curing agent. When used as a two-component curing type sealing material, a curing agent is used. Examples of the curing agent include polyester polyol, polyamine, polyether polyamine, polythiol and the like in addition to the above-mentioned polyol or polyether polyol.

[0027] The sealing material may contain other components in addition to the plasticizer of the present invention and the above-mentioned curing agent. Other components include, for example, fumed silica, precipitated silica, anhydrous silicic acid, hydrous silicic acid, carbon black, calcium carbonate, magnesium carbonate, diatomaceous earth, calcined clay,
Fillers such as clay, talc, titanium oxide, bentonite, organic bentonite, ferric oxide, zinc oxide, activated zinc white, shirasu balloon, asbestos, glass fiber, filaments, etc .; thixotropic agents such as fatty acid amide wax, hydrogenated castor oil, etc. Antioxidants such as hindered phenols and aromatic amines; light stabilizers such as benzotriazole and hindered amine; adhesives such as aminoalkoxysilanes and phenolic resins; ultraviolet absorbers, antioxidants, coloring agents, pigments, Examples include an antistatic agent, a lubricant, a flame retardant, a fungicide, a bactericide, and a thickener.

The sealing material containing the plasticizer for a sealing material of the present invention can be applied to any use requiring watertightness and airtightness. For example, household appliances that use water from refrigerators, washing machines, dryers, dishwashers, etc. from familiar places such as kitchens, washrooms, toilets, baths, window frames, shutters, roofs, gutters, etc. It can be used for watertight and airtight parts such as large industrial products such as automobiles, airplanes, ships, submarines, and spaceships, tunnels, bridges, and large viaducts.

[0029]

The present invention will be described more specifically with reference to the following examples. In the following examples, parts and percentages are by weight unless otherwise specified.

Production Example 1 Polypropylene glycol monobutyl ether (molecular weight: 400) and tolylene diisocyanate were reacted at a molar ratio of 2: 0.95 at 80 ° C. for 10 hours to obtain a plasticizer 1 of the present invention (Product 1 of the present invention). I got

(Production Example 2) Polypropylene glycol monomethyl ether (molecular weight: 1,000) and hexamethylene diisocyanate at a molar ratio of 2: 0.95 at 80 ° C.
The reaction was carried out for 10 hours to obtain a plasticizer 2 of the present invention (product 2 of the present invention).

(Production Example 3) Polypropylene glycol monophenyl ether (molecular weight: 2,000) and dodecyl isocyanate were reacted at a molar ratio of 1: 0.95 at 80 ° C. for 10 hours to obtain a plasticizer 3 of the present invention (product of the present invention). 3) was obtained.

(Production Example 4) Polypropylene glycol monomethyl ether (molecular weight: 400) and 1-methylbenzene-2,4,6-triisocyanate in a molar ratio of 3:
The mixture was reacted at 80 ° C. for 10 hours at 0.95 to obtain Plasticizer 4 of the present invention (Product 4 of the present invention).

(Production Example 5) Polyoxypropylene polyoxyethylene mono 2-ethylhexyl ether (PO:
EO = 80: 20 random adduct, molecular weight 1,00
0. ) And tolylene diisocyanate in a molar ratio of 2: 0.9
5 at 80 ° C. for 10 hours.
(Product 5 of the present invention) was obtained.

Comparative product 1: di-2-ethylhexyl phthalate Comparative product 2: polypropylene glycol dimethyl ether (molecular weight: 2,000) Comparative product 3: polypropylene glycol (molecular weight: 2,000)
0) and phenyl isocyanate in a molar ratio of 0.5: 0.9
Reaction product reacted at 5 for 10 hours.

<Example 1> A heat loss test was carried out using the plasticizers of the products 1 to 5 of the present invention obtained in Production Examples 1 to 5 and the plasticizers of the comparative products 1 to 3. That is, in a 100 mL beaker, about 10 g of each of the plasticizer samples of the present invention products 1 to 5 and comparative products 1 to 3 were sampled, left in a thermostat at 150 ° C. for 3 hours, and cooled to room temperature in a desiccator. The weight loss of each sample after heating was measured, and the weight loss rate (%) of the sample before heating was determined. At the same time, the viscosity at 25 ° C. of each sample was measured with a Brookfield rotational viscometer. Table 1 shows the results.

[0037]

[Table 1]

Example 2 Polyurethane glycol (molecular weight 2,000), glycerin propylene oxide adduct (molecular weight 3,000), and tolylene diisocyanate were reacted to obtain a urethane prepolymer (isocyanate content 1.6%). Was. 100 parts of this urethane prepolymer, 40 parts of talc, 20 parts of calcium carbonate and 0.5 part of dibutylhydroxytoluene were mixed with the product of the present invention 1
To 5 or 40 parts of each of the plasticizers of Comparative products 1 to 3 were mixed to prepare a one-part curing type sealing material composition. These compositions were evaluated in the following manner.

(Viscosity) The viscosity of the sealing material composition obtained by mixing the above components with the urethane prepolymer immediately after polymerization at 20 ° C. was measured with a Brookfield rotational viscometer. (Extrusion characteristics) Measured in accordance with JIS-A-5758. A polyethylene cartridge filled with each sealing material composition was mounted on an air gun, and almost all of the sample in the cartridge was extruded from the tip without a nozzle. The required time was determined. (Contamination) Each sealant composition was placed on a slate plate for about 5 minutes.
mm thick and cured at 20 ° C for 3 days, then apply a water-based paint (water-based acrylic lysine-based paint or water-based acrylic enamel-based paint) to a thickness of about 0.5 mm each, and use an outdoor exposure table with a 45 ° tilt angle. Exposure. It was exposed for 3 months as it was, the degree of adhesion of dirt and dust was visually observed, and the contamination was evaluated according to the following criteria. ：: No contamination. Δ: There is some contamination. ×: Contaminated. Table 2 shows the evaluation results.

[0040]

[Table 2]

Example 3 Polyurethane glycol (molecular weight: 2,000), glycerin propylene oxide adduct (molecular weight: 3,000), and tolylene diisocyanate were reacted to obtain a urethane prepolymer (isocyanate content: 2.9%). Was. 100 parts of this urethane prepolymer, 140 parts of calcium carbonate, 5 parts of a curing acceleration catalyst (lead octoate, lead content: 20%), 60 curing agents (polypropylene glycol, molecular weight: 2,000)
Parts and 0.5 part of dibutylhydroxytoluene were added with 40 parts of each of the plasticizers of the products 1 to 5 of the present invention or the comparative products 1 to 3
The two-part curing type sealing material composition was prepared by partially mixing. This sealing material composition was evaluated in the same manner as in Example 2. Table 3 shows the results.

[0042]

[Table 3]

From the above results, when the conventional phthalate plasticizer (Comparative product 1) or polyether plasticizer (Comparative product 2) was used, the viscosity was relatively low and the workability was good, but the migration property was good. And the plasticizer bleeds out to the surface to increase the contamination. In addition, a urethane polyether-based plasticizer whose terminal is not etherified (Comparative Product 3) has low contamination but high viscosity and extremely poor workability. On the other hand, the plasticizers of the present invention all have low viscosity, good plasticity and good workability, and at the same time, have an excellent effect that migration is small and thus bleed out to the surface is small and contamination is small. Is shown.

[0044]

The effect of the present invention is to provide a plasticizer for a sealing material which is excellent in plasticity, of course, has a small heating loss and a small migration property.

Continued on the front page (72) Inventor Yoshio Minowa 7-35 Higashiogu, Arakawa-ku, Tokyo Asahi Denka Kogyo Co., Ltd. F-term (reference) 4H017 AA04 AA31 AB03 AD05 AE03 4J002 CK03X CK04W CK04X FD14X GJ02 4J034 BA03 DA01 DG03 DG04 DG05 DG06 DG14 HA04 HA07 HA08 HC03 HC07 HC12 HC13 HC17 HC18 HC22 HC45 HC46 HC63 HC67 HC71 HC73 JA42 RA08

Claims (4)

[Claims] 1. The following general formula (1): (Wherein, R ¹ represents a residue obtained by removing an isocyanate group from m-valent isocyanate, R ² and R ³ represent a hydrocarbon group, m represents a number of 1 or more, and n represents a number of 1 or more. Consisting of a urethane polyether represented by the following formula:
A plasticizer for a urethane-based sealing material having an isocyanate group at a terminal. 2. m is a number of 1 to 2, and R ² is a group having 2 carbon atoms.
The plasticizer for a sealing material according to claim 1, which is an alkylene group of (1) to (4). 3. The plasticizer according to claim 1, wherein the urethane polyether represented by the general formula (1) has a molecular weight of 300 to 30,000. 4. The urethane-based sealing material having an isocyanate group at a terminal thereof has an isocyanate content of 0.5 to 5%.
The plasticizer for a sealing material according to any one of claims 1 to 3, wherein the plasticizer comprises a urethane prepolymer in an amount of 1% by weight.