JP3509967B2 - One-component heat-curable polyurethane elastomer composition and molding method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a one-component heat-hardening type polyurethane elastomer composition (hereinafter, one-component PU
E composition. ) And its forming method. More specifically, 1,5-diazabicyclo (4,5,3) is used as a ring-opening catalyst for a uretdione group in a polyurethane precursor having a predetermined ratio of uretdione groups and active hydrogen groups.
0) Nonene-5 and / or its salt (hereinafter, DBN and / or
Or called its salt. ), The composition has excellent storage stability under normal environment and high temperature (for example, about 50 ° C.), and the chain can be extended immediately by heating (for example, temperature of about 180 to 200 ° C.), A one-component PU which is a composition that crosslinks and cures and is capable of obtaining a polyurethane elastomer having good tensile properties and strain properties
The present invention relates to an E composition and a method for forming the same.

[0002]

2. Description of the Related Art Polyurethane elastomers have excellent properties such as rubber elasticity, chemical resistance, abrasion resistance, toughness, cold resistance, and durability, so that they are used as paints, floor materials, waterproof materials, adhesives, In recent years, it has been particularly used as a wall material and a sealing material. Polyurethane elastomers are roughly classified into thermoplastic elastomers and thermosetting elastomers.

The thermoplastic elastomer is a high molecular weight linear polyurethane and can be processed by a usual thermoplastic resin processing technique such as injection molding or extrusion molding. On the other hand, as the thermosetting elastomer, (1) a two-component type in which a polyisocyanate and / or an isocyanate-terminated prepolymer and a polyol are mixed and stirred immediately before use, and then poured into a mold and cured, and (2) an isocyanate-terminated There is a one-component moisture curing type that uses a prepolymer and reacts with moisture in the atmosphere to cure.

Each of these has advantages and disadvantages. The thermoplastic elastomer is a high molecular weight linear polyurethane,
Has semi-permanent storage stability and excellent workability. However, since it has no crosslinked structure, it has a low softening point and is inferior in heat resistance and compression set characteristics. Further, it generally has a high molecular weight, a high melt viscosity and a low fluidity, so that it has a drawback that it is difficult to mold a product having a complicated shape and a large size.

On the other hand, the two-component elastomer has a high fluidity immediately after mixing, and it is easy to mold a product having a complicated shape or a large product, and usually has a crosslinked structure, It has excellent heat resistance and compression set characteristics,
The two-component blended liquid thickens due to the reaction between isocyanate groups and hydroxyl groups in the system, and finally gels, so that the pot life is limited. Furthermore, in order to obtain a satisfactorily homogeneous reaction product, it is necessary to use the stoichiometric amounts of the two components, which must be precisely weighed and then mixed homogeneously.

On the other hand, the one-component moisture-curable elastomer is
Usually, it goes through a process of curing by reacting with moisture in the atmosphere,
Although the physical properties of the final elastomer are inferior to those of the two-component elastomer, they have excellent heat resistance and the like. However, since it is a reaction with moisture, the reaction is slow and it takes a long time to completely cure. In addition, the above-mentioned two types of thermosetting elastomers contain a small amount of free polyisocyanate monomer in the system, which adversely affects the working environment depending on the conditions during molding processing. Often needed.

Various proposals have been made for improving these polyurethane elastomers. For example, in the case of a two-component elastomer, a blocking agent dissociates and scatters when heated to 120 ° C. or higher, and a blocking agent that regenerates an isocyanate group is used. Is proposed. However, although storage stability is improved by this method, at the time of curing, problems such as pollution problems due to foaming of the elastomer by the blocking agent and scattering of the blocking agent or deterioration of the physical properties of the elastomer due to the residual blocking agent remain,
It is used in some applications as a one-component paint system in the paints field, but is rarely used in the elastomer field.

On the other hand, in the one-component moisture-curable elastomer, a formulation which is not so much influenced by external conditions such as introduction of a water-absorbing composition or addition of a catalyst, a curing agent such as ketimine or aldimine compound which generates an amino group by moisture, and an isocyanate. Apparent one-component compositions based on a terminal prepolymer system have been proposed. However, a complete one-component elastomer having excellent long-term storage stability, workability, and physical properties of elastomer has not yet been developed, and its development is now strongly desired. Further, from the viewpoint of environmental problems on a global scale, development of a polyurethane elastomer composition containing no free isocyanate monomer has been strongly desired.

Polyurethane resins containing a polyisocyanate having a uretdione group as one of the raw material components are known, but the uretdione group is opened to sufficiently react and cure to obtain an elastomer having excellent performance. Therefore, it is necessary to heat at a high temperature of 180 ° C. or higher for a long time. Therefore, trialkylphosphine-based catalysts such as triethylphosphine, amines such as triethylamine, triethylenediamine (hereinafter referred to as TEDA), and 1,8-diazabicyclo (5,4,0) undecene-7.
Amine-based catalysts such as diaza-bisiroc-alkenes (hereinafter referred to as DBU) and the like are often added as catalysts for promoting ring-opening of the uretdione group.

However, the above phosphine-based and amine-based catalysts cannot sufficiently accelerate the ring-opening of the uretdione group, and when DBU is used, the reaction and curing temperatures can be lowered. However, the reaction may proceed to some extent even at room temperature, the raw material may thicken with time, and eventually gel. Therefore, the raw material for elastomers containing DBU has a limited pot life,
There is a problem with storage stability.

[0011]

DISCLOSURE OF THE INVENTION The present invention provides (1) rubber elasticity, chemical resistance, abrasion resistance, toughness, cold resistance and durability due to the large cohesive energy that is characteristic of conventional polyurethane elastomers. Having, (2) having a semi-permanent storage stability equivalent to that of the thermoplastic polyurethane elastomer, (3) having excellent heat resistance due to a cross-linking structure, compression set characteristics, etc. formed by a curing reaction, (4) Can be molded by conventional thermoplastic resin processing technologies such as injection molding and extrusion molding, (5) In relation to environmental issues,
Free polyisocyanate monomer does not generate or scatter during operations such as compounding and heating, and (6) excellent storage stability even in the temperature range of about 50 ° C, and 180-
An object of the present invention is to provide a one-component PUE composition that satisfies various conditions such that curing is completed in a short time only by heating to a high temperature of 200 ° C. and a molding processing method thereof.

[0012]

[Means for Solving the Problems] One-component system P of the first invention
The UE composition comprises a polyurethane precursor composed of a polyisocyanate component and a compound having an active hydrogen group, DBN
And / or a composition for a polyurethane elastomer containing a salt thereof, wherein the polyisocyanate component contains a polyisocyanate having at least a uretdione group, and the compound having an active hydrogen group has at least two active hydrogen groups in the molecule. Having a molecular weight of 18 to 20,000
The polyurethane precursor is obtained by reacting under a condition that the equivalent ratio of the active hydrogen group of the compound having the active hydrogen group to the isocyanate group of the polyisocyanate component exceeds 1.0, and The equivalent ratio of uretdione groups to active hydrogen groups in the polyurethane precursor is 0.25 to 1.0.

Further, the molding and processing method of the one-component PUE composition of the fourth invention is such that the one-component PUE composition of the first invention is injected at a temperature not higher than the temperature at which the uretdione group is ring-opened, and after molding, the uretdione group is formed. Is heated to a temperature above the ring-opening temperature for reaction and curing, and a fifth aspect of the present invention comprises heating the one-component PUE composition of the first aspect above the temperature at which the uretdione group is ring-opened, followed by injection, It is characterized by being molded, reacted and cured.

The above-mentioned "polyisocyanate component" includes a polyisocyanate having at least a uretdione group. In general, the object of the present invention is achieved by having a uretdione group, but a polyisocyanate having other groups derived from an isocyanate group such as an isocyanurate group in addition to the uretdione group may be contained. As the groups other than the above-mentioned two types derived from an isocyanate group,
Examples thereof include urethane group, urea group, carbodiimide group, uretonimine group, oxazolidone group and hydantoin group.

These polyisocyanates may be used either individually or in combination of two or more. For example, it may be a mixture of a polyisocyanate having a uretdione group and a polyisocyanate having a uretdione group and an isocyanurate group. If desired, one or more polyisocyanate monomers having two or more isocyanate groups in the molecule may be used in combination as the polyisocyanate component. Incidentally, this polyisocyanate monomer not only remains unreacted in the dimerization reaction described below, but also lowers the average number of functional groups in the polyisocyanate component and gels during the production of a polyurethane precursor by reaction with a compound having an active hydrogen group. To further suppress the
It may be added appropriately.

The polyisocyanate constituting the above polyisocyanate component includes not only polyisocyanate monomer but also its polymer. As the polyisocyanate monomer, 2,4-tolylene diisocyanate,
2,6-Tolylene diisocyanate, xylene-1,4
-Diisocyanate, xylene-1,3-diisocyanate, 4,4'-diphenylmethane diisocyanate,
4,4'-diphenyl ether diisocyanate, 2-
Nitrodiphenyl-4,4'-diisocyanate, 2,
2'-diphenylpropane-4,4'-diisocyanate, 3,3'-dimethyldiphenylmethane-4,4'-
Diisocyanate, 4,4'-diphenylpropane diisocyanate, m-phenylene diisocyanate, p-
Aromatic diisocyanates such as phenylene diisocyanate, naphthylene-1,4-diisocyanate, naphthylene-1,5-diisocyanate, 3,3'-dimethoxydiphenyl-4,4'-diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, etc. And diisocyanates such as alicyclic diisocyanates such as hydrogenated tolylene diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate, hydrogenated diphenylmethane diisocyanate and tetramethyl xylene diisocyanate. Among these,
Aliphatic diisocyanates and alicyclic diisocyanates are particularly preferable. Further, it is also possible to use a polyisocyanate obtained by reacting a polymer of these diisocyanates or a polyol having two or more functional groups with the above diisocyanate or a polymer thereof.

The polyisocyanate compound having a uretdione group, which is an essential component in the present invention, and the polyisocyanate compound having another group such as an isocyanurate group which may be used in combination are generally the dimerization reaction (uretdione) of a polyisocyanate monomer. Chemical reaction), trimerization reaction (isocyanurate reaction), and the like, and specifically can be produced, for example, as follows.

In the presence of a uretdione-forming catalyst, for example, triethylphosphine, dibutylethylphosphine, tri-n-propylphosphine, triamylphosphine, tribenzylphosphine, or another trialkylphosphine, or pyridine, the reaction temperature is usually 0 to 90 ° C. In the absence of solvent or an inert solvent, for example, toluene, xylene and other aromatic solvents, methyl ethyl ketone, ketone solvents such as methyl isobutyl ketone, ethyl acetate, ester solvents such as butyl acetate, propylene glycol methyl ether acetate, It can be produced in the presence of a glycol ether ester solvent such as ethyl-3-ethoxypropionate and, in some cases, in the presence of a plasticizer such as a liquid polyol or dioctyl phthalate at the reaction temperature.

In this reaction, when 20 to 50 mol% of isocyanate groups are reacted, the reaction solution is treated with, for example, phosphoric acid,
A solution of methyl paratoluenesulfonate, sulfur or the like is added to inactivate the uretdione-forming catalyst to stop it. Depending on the type of polyisocyanate used, some may be crystallized and precipitated during this reaction process. Particularly, the aromatic polyisocyanate easily crystallizes and is separated from the reaction system. By such a method, a polyisocyanate having a uretdione group (that is, a dimer and a polyuretdione body),
And a mixture containing both a uretdione group and an isocyanurate group, and optionally a polyisocyanate having another group, and a raw material polyisocyanate monomer.

The above mixture may be used as an isocyanate component as it is, or may be obtained by removing unreacted monomers from this mixture by thin film distillation or the like.
In the above-mentioned dimerization reaction, the higher the reaction temperature at the time of production and the lower the content of the polyisocyanate monomer at the time of stopping the reaction, the higher the production ratio of isocyanurate groups becomes. In addition, the larger the amount of catalyst such as triethylphosphine, the higher the uretdione group formation rate. By controlling these reaction conditions, a polyisocyanate compound containing a specific ratio of uretdione groups and isocyanurate groups can be obtained.

In the present invention, when the polyisocyanate component contains a fixed proportion of isocyanurate groups in addition to the uretdione groups, the heat resistance and compression set characteristics are further improved as compared with conventional polyurethane elastomers. A high-quality elastomer with low bleeding property can be obtained even at low hardness.

That is, in the one-component PUE composition of the present invention, when the polyisocyanate component contains a fixed ratio of isocyanurate groups and / or other polymers in addition to the uretdione groups, It is possible to introduce branch points into the polyurethane precursor to the extent that gelation is not reached. Therefore, as compared with an elastomer obtained from a conventionally known polyisocyanate having a uretdione group, it is possible to obtain a substance having more excellent physical properties in a short time and at a low reaction rate.

The above-mentioned "compound having an active hydrogen group" is a compound having a molecular weight of 1 having at least two active hydrogen groups in the molecule.
8 to 20,000. As the compound having an active hydrogen group, in addition to water, one or two selected from a polyol, a polyamine having an amino group, a urea resin, a melamine resin, an epoxy resin, a polyester resin, an acrylic resin, polyvinyl alcohol and the like. More than one species can be used. When a compound other than the polyol is used, an elastomer having no urethane bond can be produced, but in the present application, such a composition is also included in the one-component PUE composition.

As the above-mentioned polyol, known polyols can be used, and since the isocyanate group of the polyisocyanate component is bifunctional or higher, a low-functionality such as bifunctional is used in order to prevent gelation during the production of the polyurethane precursor. Base number polyols are suitable. Examples of polyols include polyester polyols, polyester amide polyols, polyether polyols, polyether ester polyols and polycarbonate polyols.

Examples of polyester polyols include dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, azelaic acid, terephthalic acid, isophthalic acid, hexahydroterephthalic acid, and hexahydroisophthalic acid.
Examples thereof include polyester polyols and polyester amide polyols obtained by a dehydration condensation reaction of those acid esters and acid anhydrides and the like, polyhydric alcohols such as glycols and amines alone, or a mixture thereof.

The glycols include ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol (hereinafter referred to as 1,2-PG), 1,4.
-Butylene glycol (hereinafter referred to as 1,4-BG), 1,5-pentane glycol, 1,6-hexane glycol (hereinafter referred to as 1,6-HG), 3-methyl-1,5-pentane glycol , Neopentyl glycol, 1,8-octane glycol, 1,9-nonanediol, diethylene glycol, cyclohexane-
1,4-diol, cyclohexane-1,4-dimethanol, dimer acid diol, ethylene oxide or propylene oxide adduct of bisphenol A and the like can be mentioned. As the trihydric or higher polyhydric alcohol, trimethylolpropane (hereinafter referred to as TMP), glycerin, hexanetriol and N, N, N ', N'- are used.
Tetrakis (2-hydroxypropyl) ethylenediamine or the like can be used.

As the amines, diamines such as hexamethylenediamine, xylenediamine, isophoronediamine, diethanolamine, triethanolamine and isopropanoltriamine, triamines or aminoalcohols are used. Further, as the polyester polyol, ε-caprolactone, alkyl-substituted ε
A lactone-based polyester polyol obtained by ring-opening polymerization of a cyclic ester (that is, lactone) monomer such as -caprolactone, δ-valerolactone, or alkyl-substituted δ-valerolactone can also be used.

Examples of the polyether polyol include polyethylene glycol, polypropylene ether polyol, polytetramethylene ether polyol and the like. Further, as the polyether / ester polyol, a polyester polyol produced from the above polyether polyol and a dicarboxylic acid, an acid anhydride or the like can be used.

Polycarbonate polyols are, for example,
Obtained by the reaction of hexane glycol, 3-methyl-1,5-pentanediol, 1,4-cyclohexanedimethanol and the like with diethyl carbonate, diphenyl carbonate and the like, and specific products are those manufactured by Nippon Polyurethane Industry Co., Ltd. Name "N-980", "N-98"
1 ”and the like.

Further, polyhydric alcohols such as monomolecular glycols mentioned as the raw material of the polyester polyol,
That is, ethylene glycol, 1,3-propylene glycol, 1,2-PG, 1,4-BG, 1,5-pentane glycol, 1,6-HG, 3-methyl-1,5-pentane glycol, neopentyl Glycol, 1,8-octane glycol, 1,9-nonanediol, diethylene glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, dimer acid diol, TMP, glycerin, hexanetriol, N,
N, N ', N'-tetrakis (2-hydroxypropyl) ethylenediamine, ethylene oxide or propylene oxide adduct of bisphenol A, and the like can also be used in the present invention as polyether polyols.

Further, examples of the amino group-containing polyamines include monomolecular diamines, triamines, aromatic diamines, and polyether polyamines in which the end of the polyether is an amino group. Further, urea resin, melamine resin, epoxy resin, polyester resin, acrylic resin, polyvinyl alcohol, etc. may be used as all or part of the compound having an active hydrogen group of the present invention as long as they have at least two active hydrogen groups. Can be used.

The compound having an active hydrogen group exemplified above has a molecular weight of 18 to 20,000, and particularly preferably water (molecular weight 18) and a molecular weight of 400 to 10,000. When the molecular weight exceeds 20,000, the content of uretdione groups, isocyanurate groups, urethane groups and the like in the elastomer is relatively decreased, and the toughness and strong cohesive force of the resulting elastomer are reduced, which is not preferable. If the molecular weight is less than 400 excluding water, the elastomer becomes brittle, which is not preferable. This molecular weight must be appropriately selected depending on the application, and it is preferable to use a low molecular weight one in order to increase the heat resistance and cohesive energy of the elastomer. still,
When water, polyamine, or the like is used as the compound having an active hydrogen group, a compound having a urea bond is produced.

The above-mentioned "polyurethane precursor" is obtained by reacting the above polyisocyanate component and a compound having an active hydrogen group under an active hydrogen group excess condition in which the equivalent ratio of uretdione groups to isocyanate groups exceeds 1.0. And the equivalent ratio of uretdione groups to active hydrogen groups is 0.25 to 1.0, preferably 0.35 to 0.75. In this reaction system, since the active hydrogen groups are excessive, isocyanate groups do not substantially remain in the resulting polyurethane precursor, and a polyurethane precursor having only active hydrogen groups can be obtained.

The equivalent ratio of the uretdione group to the active hydrogen group is important, and if this ratio is less than 0.25, the amount of chain extension and crosslinking will decrease, and the physical properties of the polyurethane elastomer will deteriorate. If it exceeds 0.0, gelation tends to occur during the production of the polyurethane precursor, which is not preferable. In order to make the equivalent ratio of the uretdione group to the active hydrogen group in the above range, the average functional group number of the polyisocyanate component considering the content of the isocyanurate group and the like, and a compound having an active hydrogen group considering the triol introduction and the like. The compounding ratio may be determined in consideration of the average number of functional groups and the reactivity ratio of the functional groups, and the reaction may be performed at a temperature below the temperature at which the uretdione group opens. Thereby, the precursor can be obtained without gelation.

In addition to the uretdione group and the active hydrogen group, the above-mentioned precursor may be an isocyanurate group, a urethane group, a urea group, a carbodiimide group, a uretonimine group, an oxazolidone group, depending on the polyisocyanate component used.
A group derived from an isocyanate group such as a hydantoin group may be present.

Next, the production of the polyurethane precursor will be described in detail. The polyurethane precursor may be in a molten state, a bulk state, or an inert solvent as required, for example, an aromatic hydrocarbon solvent such as toluene or xylene, an ester solvent such as ethyl acetate or butyl acetate, methyl ethyl ketone, cyclohexanone or the like. Ketone-based solvent, glycol ether ester-based solvent such as ethylene glycol ethyl ether acetate, propylene glycol methyl ether acetate, ethyl-3-ethoxypropionate,
Ether solvents such as tetrahydrofuran and dioxane,
And one or more polar solvents such as dimethylformamide, dimethylacetone, N-methylpyrrolidone, and furfural are used, and the temperature at which the uretdione group does not open, preferably 100 ° C. or lower (for example, 25 to 90 ° C.)
Then, it can be manufactured by uniformly mixing and reacting each component within the above-mentioned blending range.

In the system using the above solvent, the polyurethane precursor can be obtained by separating and recovering the solvent and the like by thin film distillation after completion of the reaction. The reaction temperature is more preferably 60 to 90 ° C. In this case, ring-opening of the uretdione group does not occur and sufficient reaction can be carried out in a short time. Further, as the apparatus for the above reaction, any apparatus can be used as long as the above homogeneous reaction can be achieved, and examples thereof include a mixing and kneading apparatus such as a reaction kettle equipped with a stirrer or a kneader, a single-screw or multi-screw extruder. To be Further, in order to increase the reaction rate, a metal catalyst such as dibutyltin dilaurate or a tertiary amine catalyst such as triethylamine may be used.

The above-mentioned "DBN and / or salt thereof", which is one of the essential components of the one-component PUE composition of the present invention, is 0.
1 to 5.0 parts by weight, especially 0.3 to 3.0 parts by weight are blended. If the amount is less than 0.1 part by weight, the ring-opening of the uretdione group is not sufficiently promoted, and if it exceeds 5.0 parts by weight, the physical properties of the resulting elastomer are affected, which is not preferable. This DBN and / or its salt may be added as one component during the preparation of the precursor, or may be additionally added to the precursor after the preparation. In any case, it can be blended at a temperature below the ring-opening temperature of the uretdione group by adequately stirring and mixing with a kneading roll, a kneader, a Banbury mixer, or other appropriate kneader.

As the DBN salt, a fatty acid salt, a salt of a phenol or the like can be used. Fatty acids that form salts include formic acid, acetic acid, propionic acid, lactic acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, undecylic acid, lauric acid, tridecyl acid, myristic acid, pentadecyl acid. , Saturated fatty acids such as palmitic acid, heptadecyl acid, stearic acid, acrylic acid, crotonic acid, isocrotonic acid, undecylenic acid, oleic acid, elaidic acid, cetoleic acid, erucic acid, placidic acid, sorbic acid, linoleic acid, linolenic acid, In addition to unsaturated fatty acids such as arachidonic acid, propiolic acid, and stearolic acid, isoalkyl fatty acids such as 2-ethylhexanoic acid, or oxyfatty acids such as lactic acid, glycolic acid, ricinoleic acid, and oxystearic acid are particularly limited. Can be used without

As the phenols, phenol, cresols, xylenols, naphthols, trimethylphenols, tetramethylphenols, pentamethylphenol, ethylphenols, n- and iso-propylphenols, n- and iso-butylphenols, cyclohexylphenols, n- and iso-amylphenols, iso-octylphenols, iso-nonylphenols, iso-dodecylphenols, di- and polysubstituted phenols (eg thymol, carvacrol, diphenol). -Iso-alkylphenols), methoxyphenols (eg, eugenol, guaiacol), and other divalent phenols such as catechols, resorcins, hydroquinones, and bisphenols. Other such Nord compounds, pyrogallol, include polyhydric phenols such as phloroglucinol. Of these, phenol and para-lower alkylphenols (eg, paracresol, paraethylphenol) and the like are preferable.

The above-mentioned salt can be produced by simply mixing DBN and a fatty acid or a phenol, and the reaction proceeds easily at room temperature without requiring a special catalyst. Both react in an equivalent amount, but a salt in which DBN is present in excess and a salt in which fatty acids or phenols are present in excess can also be used. When the fatty acid or phenol is a solid, it is preferable to use an inert volatile solvent such as benzene, toluene, xylene or hexane for the reaction. Although the obtained salt does not need to be purified, if a high-purity salt is required, the purity may be increased by recrystallizing it from a solvent such as isooctane.

The one-component PUE composition of the present invention may be liquid, solid, powder or the like in the normal state. Further, after production, it can be aged in dry air at 60 to 90 ° C. for 24 to 48 hours, and then finished in a granular form again by a pelletizer, or the aged product can be finished by freezing and crushing using liquid nitrogen. Particularly in the case of fine pulverization, instead of the above solid operation, a solvent compatible with water, such as dimethylformamide, tetrahydrofuran, etc., is added to the raw material, and the one in a solution state is put into water to disperse the resin component. It is also possible to separate and precipitate to obtain fine powder. In the case of this solution operation, it is necessary to confirm that the isocyanate groups have completely disappeared.

Further, in order to improve the function of the obtained elastomer, the above-mentioned compound having an active hydrogen group is additionally added to the main component polyurethane precursor, and the uretdione group based on the total active hydrogen group of the active hydrogen group of the precursor is added. Equivalent ratio of 0.25 to 1.00, preferably 0.35 to 0.75
It can also be adjusted to be within the range. In addition, anti-gelling agents such as ester / urethane exchange reaction inhibitors that prevent gelation during storage, other antioxidants, ultraviolet absorbers, hydrolysis inhibitors, colorants, flame retardants, viscosity modifiers,
It can also be prepared by blending a flowability improver, a plasticizer, a thixotropic agent, a filler and the like.

Further, a physical foaming agent such as methylene chloride, freon compound, pentane, azobisisobutyronitrile, azodicarbonamide, N,
It is also possible to obtain a foamed elastomer by using an organic foaming agent such as N'-dinitrosopentamethylenetetramine and an inorganic foaming agent such as sodium bicarbonate, ammonium carbonate, sodium borohydride, alone or in combination, or by foaming by the floss method. it can. In addition, in order to obtain the foamed elastomer, a foam stabilizer, silicone, an organic surfactant and the like can be used if necessary.

The method for obtaining the polyurethane elastomer from the above composition may be selected according to the shape of the product and the curing conditions. For example, as in the fourth invention, the one-component PUE is used.
After injecting the composition into a mold by casting, extrusion molding, injection molding, blow molding, vacuum molding, compression molding or the like, or after coating the mold by spraying, coating, etc., heat energy is applied to react. Either curing or molding, or applying thermal energy as in the fifth invention, and then injecting it into a mold by the above-mentioned molding methods such as casting, and reacting and curing, whichever method. It may be.

It is necessary that the heating temperature and time for the above-mentioned molding be the conditions under which the uretdione group is opened.
It is suitable to be several minutes to several tens of minutes at 160 to 220 ° C., but it depends on the shape and design of the product. This temperature is 160 ℃
If it is less than 1, the ring opening and reaction do not proceed sufficiently. Also, 22
If it exceeds 0 ° C, the physical properties of the obtained elastomer may deteriorate. The obtained elastomer can be made into a product having higher strength by aging at 90 to 120 ° C. for several hours, if necessary, and finally chain extension and crosslinking are completed to obtain strength, strain characteristics, etc. It is possible to obtain an excellent elastomer.

When the equivalent ratio of the polyurethane precursor is in the range of more than 0.5 to 1.0, the uretdione group becomes excessive, and the one-component PUE composition of the present invention depends on the reaction with moisture in the environment. It is also possible to carry out chain extension and / or cross-linking by chain extension, cross-linking, reaction with allophanate or burette by reaction with urethane group, urea group, etc., and polymerization reaction with isocyanate group alone, for example, carbodiimidization, isocyanurate formation, etc. . If the obtained elastomer has good physical properties, it is not necessary to open all uretdione groups. The equivalence ratio is 0.25
If it is at least 0.5 and less than 0.5, the active hydrogen group becomes excessive and the precursor behaves thermoplastically.

[0048]

In the one-component PUE composition of the present invention, isocyanate groups including the free polyisocyanate monomer are substantially absent at room temperature, and when heated to a temperature higher than a predetermined temperature, a plurality of uretdione groups are opened to open the isocyanate group. The active isocyanate groups of are regenerated. Therefore, at a predetermined temperature or lower, the pot life is not limited as in the two-component polyurethane elastomer composition, and the composition has semipermanent storage stability. Further, since the regenerated isocyanate group is attached to the terminal of the molecule in the ring-opened polyurethane precursor, there is no generation or scattering of free polyisocyanate monomer, and the handling is safe in the working environment.

The composition of the present invention is a one-component system,
It is characterized in that it does not require strict weighing and uniform mixing of the two components unlike the two-component polyurethane elastomer composition. Furthermore, since DBN and / or a salt thereof which is a catalyst for promoting the ring-opening of the uretdione group is blended, the uretdione group is rapidly ring-opened at a temperature higher than the ring-opening temperature, as if it were a two-component polyurethane elastomer composition. As described above, due to the reaction between the regenerated isocyanate group and the terminal active hydrogen group, chain extension and / or cross-linking proceeds rapidly, and the reaction cures to obtain a uniform reaction product.

[0050]

EXAMPLES The present invention will be described in more detail with reference to the following examples. In the following examples and the like, all "parts" mean "parts by weight". (1) Preparation of One-Component PUE Composition and Production of Elastomers Examples 1 to 3 One-component PUE composition containing no uretdione group and active hydrogen group in a predetermined ratio without containing free polyisocyanate, PUE-1 , PUE-2, and PUE-3 (the details are shown in Table 1. The HDIs in Table 1 are 1, 6).
Abbreviation for hexamethylene diisocyanate. ) 1 each
0.5 parts of DBN, which is a ring-opening catalyst, in 00 parts, and an antioxidant (trade name "Irganox 10" manufactured by Ciba-Geigy).
10 ") 0.5 part was added, and the mixture was put into a flask set at a temperature of 80 ° C., stirred for 30 minutes and mixed to give one-component system P.
It was a UE composition.

[0051]

[Table 1]

Thereafter, each of the above compositions was subjected to compression molding using a lab press at a temperature of 200 ° C. and a pressure of 12 kg / c.
It was cured at m ² for 10 minutes to prepare an elastomer sheet having a thickness of about 2 mm. Further, as a sample for measuring the compression set, a molded product having a diameter of 29 mm and a thickness of 12.5 mm was produced by casting, and similarly cured at 200 ° C. for 10 minutes and used for the test.

Examples 4-5 PUE-1 was used as the one-component PUE composition and DB
In the same manner as in Examples 1 to 3, except that DBN / octylate (Example 4) and DBN / phenol salt (Example 5), which are salts of DBN instead of N, were added in an amount of 1.0 part each. An elastomer sheet having a thickness of about 2 mm and a sample for measuring compression set were prepared.

Comparative Examples 1 to 3 In the same manner as in each example, except that DBN was not mixed and curing was performed at 200 ° C. for 30 minutes (a sheet could not be prepared by curing for 10 minutes), the thickness was about 2 mm. An elastomer sheet and a sample for measurement of compression set were prepared. Comparative Examples 4 to 6 It was attempted to prepare an elastomer in the same manner as in each example except that DBU and 0.5 part were blended as the ring-opening catalyst instead of DBN, but thickening started immediately after stirring for 10 minutes. Gelation occurred within that time, and it was not possible to sufficiently defoam, and an elastomer could not be produced.

Comparative Example 7 PUE-1 was used as a one-component PUE composition and DB
Add 1.0 parts of TEDA instead of N, and add 30 at 200 ° C.
Except for curing for 1 minute (as in Comparative Examples 1 to 3, 1
A sheet could not be produced by curing for 0 minutes. ), And an elastomer sheet having a thickness of about 2 mm and a sample for measuring compression set were prepared in the same manner as in each example.

(2) Stability of one-component PUE composition The stability of the composition in the atmosphere of 25 ° C. and 50 ° C. was evaluated by visually observing the state of gelation. <Criteria> ×: Gelation within 1 day ○: Stable for 21 days or more

(3) Physical Properties of Elastomer Time and Hardness Required for Curing of Examples and Comparative Examples, Tensile Strength, Elongation at Break, Tear Strength, 25% Compression Set (70%)
(° C, 22 hours) was measured. Each physical property is JIS K630
It measured according to 1. The stability of the one-component PUE compositions of Examples 1-5 and Comparative Examples 1-7 are shown in Tables 2 and 3, respectively.
Table 4 shows the curing time of the compositions of the same Examples and Comparative Examples 1 to 3 and Comparative Example 7, and the physical properties of the obtained elastomers, respectively.

[0058]

[Table 2]

[0059]

[Table 3]

[0060]

[Table 4]

[0061]

[Table 5]

According to the results of Table 2, the one-component system P of the present invention
It can be seen that the UE composition is extremely excellent in storage stability, not to mention gelation not only at 25 ° C. but also at a considerably high temperature of 50 ° C. On the other hand, according to the results of Table 3, Comparative Examples 1 to 3 and Comparative Example 7 are similarly excellent in storage stability, but in Comparative Examples 4 to 6, thickening starts immediately after stirring as described above, It gels within 10 minutes and is extremely inferior in storage stability.

Furthermore, according to the results of Table 4, the curing time of the one-component PUE composition of the present invention is as short as 10 minutes, and the obtained elastomer has excellent physical properties, particularly compression set characteristics. It turns out that it is a thing. On the other hand, according to the results shown in Table 5, in Comparative Examples 1 to 3 in which DBN was not added, the curing time was 30 minutes, which was very long, and the tensile strength and the elongation at break were decreased. It can be seen that the distortion characteristics are greatly reduced. Further, in the case of Comparative Example 7 in which TEDA was used instead of DBN, it was found that the curing time and the physical properties were inferior as in Comparative Examples 1 to 3.

[0064]

The one-component PUE composition of the first invention is a one-component system, and like the composition for thermoplastic elastomers,
It has excellent workability during use and has semi-permanent storage stability in the temperature range from room temperature to about 50 ° C.
The temperature at which the uretdione group is opened, for example, 180 ° C
Only by heating to a high temperature, it is possible to obtain an elastomer having excellent heat resistance and durability by reacting with active hydrogen groups and curing.

Further, rubber elasticity, chemical resistance, abrasion resistance, toughness, cold resistance, durability, etc. can be controlled within a preferable range by appropriately selecting the skeleton structure and the active hydrogen compound used. it can. In addition, the composition of the present invention,
It does not contain free polyisocyanate monomer that causes environmental problems at room temperature, and does not generate free polyisocyanate monomer found in some blocked isocyanates even when cured at high temperatures, so it can be handled safely in a good working environment. You can

In the second invention, a more efficient reaction-promoting effect is obtained by using an appropriate amount of the ring-opening catalyst of the first invention, and as in the third invention, it has an isocyanurate group in addition to the uretdione group. By using an isocyanate component, an elastomer having more excellent physical properties can be obtained. Further, the composition of the first to third inventions, as in the fourth or fifth invention, is molded at a temperature below the ring-opening temperature of the uretdione group and then cured by heating, or after being heated to a temperature above the ring-opening temperature, It can be molded or can be molded by any simple method.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yukihiro Morikawa 3-5-37 Tsunashima-higashi, Kohoku-ku, Yokohama-shi, Kanagawa (56) Reference JP-A-6-172735 (JP, A) (58) Fields investigated ( Int.Cl. ⁷ , DB name) C08G 18/00-18/87

Claims (5)

(57) [Claims] 1. A polyurethane precursor comprising a polyisocyanate component and a compound having an active hydrogen group is added with 1,5
A polyurethane elastomer composition containing diazabicyclo (4,3,0) nonene-5 and / or a salt thereof, wherein the polyisocyanate component contains a polyisocyanate having at least a uretdione group and has the active hydrogen group. Has at least two active hydrogen groups in the molecule and has a molecular weight of 18 to 20,000, and the polyurethane precursor is the equivalent of the active hydrogen group of the compound having the active hydrogen group to the isocyanate group of the polyisocyanate component. The ratio of uretdione groups to the active hydrogen groups in the polyurethane precursor is 0.2.
A one-component heating fast-curing polyurethane elastomer composition, which is 5 to 1.0. 2. The 1,5-diazabicyclo (4,3,
0) The compounding amount of nonene-5 and / or its salt is 0.1 to 100 parts by weight of the polyurethane precursor.
It is 5.0 parts by weight, and the one-component rapid heating and curing type polyurethane elastomer composition according to claim 1. 3. The one-component rapid thermal curing type polyurethane elastomer composition according to claim 1, wherein the polyisocyanate component has a uretdione group and an isocyanurate group derived from an isocyanate group. 4. The one-component system heat-curing polyurethane elastomer composition according to claim 1, 2 or 3 is injected at a temperature not higher than the temperature at which the uretdione group opens, and after molding, a temperature not lower than the ring opening at the uretdione group. A method for molding and processing a one-component system rapid curing type polyurethane elastomer composition, which comprises heating to react and cure. 5. The one-component system heat-curable polyurethane elastomer composition according to claim 1, 2 or 3 is heated to a temperature at which the uretdione group is ring-opened or higher and then injected, molded, reacted and cured. A method for molding and processing a one-component heating fast-curing polyurethane elastomer composition, which is characterized.