JP5168721B2 - Urethane elastomer forming composition and method for producing thermosetting urethane elastomer - Google Patents

Description

  The present invention relates to a method for producing a thermosetting polyurethane elastomer having a small hardness creep and capable of being quickly removed, which is used for industrial equipment parts.

  A castable thermoset polyurethane elastomer molded article is suitably used as a part for industrial equipment that requires high physical properties.

  As a component forming a composition for molding a thermosetting polyurethane elastomer, an isocyanate group-containing urethane prepolymer obtained by reacting diphenylmethane diisocyanate and a hydroxyl group-containing polyol is preferably used. As the hydroxyl group-containing curing agent component, A mixture of 1,4-butanediol and trimethylolpropane is preferably used.

  In general, when molding parts for industrial equipment, an isocyanate group-containing urethane prepolymer and a hydroxyl group-containing curing agent are uniformly mixed with a mixing head of a casting machine, immediately before molding a forming composition (mixed liquid). Then, the composition can be immediately poured into a preheated mold, and the composition can be produced by heat curing (urethanization) in the mold.

  However, in order to efficiently produce a thermosetting polyurethane elastomer molded product having desired performances, the composition must be instantaneously heat-cured (urethane) in a mold. By adding a catalyst in advance to the hydroxyl group-containing curing agent side to promote heat curing (urethanization) and shortening the occupation time of the mold, it can be efficiently produced (rapid demolding property).

  In general, amine catalysts such as triethylenediamine and dimethylethanolamine or metal catalysts such as dibutyltin dilaurate and dioctyltin dilaurate are often used as the catalyst. However, since the urethanization reaction is promoted simultaneously with the start of mixing of the isocyanate group-containing urethane prepolymer and the hydroxyl group-containing curing agent, and an increase in viscosity is observed, the liquid mixture (in particular, in the mold of industrial equipment used for fine parts) (Urethane resin) may not flow sufficiently.

  As a means for solving such a series of problems, a molding method using a metal acetate-based trimerization catalyst as a main catalyst has been proposed.

  In this case, the introduction of these can reduce the initial mixing viscosity and shorten the mold occupation time (hereinafter referred to as demoldable time), but the isocyanurate bond occupying in the composition is caused by the trimerization catalytic effect. The proportion occupied becomes large, and a hardness creep phenomenon is observed in the molded product, and it becomes impossible to have various performances such as desired shape maintenance and recovery, tensile strength, elongation rate and the like. For this reason, it is necessary to generate isocyanurate bonds and urethane bonds in a well-balanced manner, and it is necessary to accelerate the urethanization reaction in parallel.

  In general, amine-based catalysts such as triethylenediamine and dimethylethanolamine, which are used as catalysts for urethanization, have a low urethanation activity, so it is necessary to increase the number of parts added, but they are incorporated into equipment as industrial equipment parts. After that, the catalyst is contaminated with bloom, so that the method of increasing the catalyst is not preferable. In addition, tin-based catalysts such as dibutyltin dilaurate and dioctyltin dilaurate having high urethanization activity are not preferable because the initial mixed viscosity of the isocyanate group-containing urethane prepolymer and the hydroxyl group-containing curing agent becomes very high.

JP2004-64603 JP 2008-8957

The present invention has been made based on the above situation.
The first object of the present invention is to provide a thermosetting polyurethane elastomer-forming composition having various properties such as desired tensile strength and elongation of a conventionally known thermosetting polyurethane elastomer and further having reduced hardness creep. There is.

  A second object of the present invention is to provide a thermosetting polyurethane elastomer-forming composition that has various properties such as desired tensile strength and elongation of a conventionally known thermosetting polyurethane elastomer and that can shorten the demoldable time. There is to do.

  The third object of the present invention is to provide a thermosetting polyurethane elastomer-forming composition that has various properties such as desired tensile strength and elongation of a conventionally known thermosetting polyurethane elastomer and is less contaminated by catalyst bloom. There is.

  The fourth object of the present invention is to form a thermosetting polyurethane elastomer having various properties such as desired tensile strength and elongation of a conventionally known thermosetting polyurethane elastomer and having a short curing time after demolding and high hardness development. It is to provide a sex composition.

  The fifth object of the present invention is excellent in productivity with performance as a part of industrial equipment, using the thermosetting polyurethane elastomer-forming composition that has solved the first to fourth objects. It is providing the manufacturing method of a thermosetting polyurethane elastomer.

  As a result of intensive studies to achieve these objects, the inventors of the present invention have a catalyst represented by the general formula (1) when an isocyanate group-containing urethane prepolymer is mixed with a hydroxyl group-containing curing agent. By using three types of catalysts (C1), an acetic acid metal salt catalyst (C2) and an amino alcohol catalyst (C3), it was found that the above-mentioned series of problems could be solved, and the present invention was completed.

That is, this invention is shown by the following (1)-(7).
(1) The mixing ratio α (hydroxyl group (mol) / NCO group (mol)) of the isocyanate group-containing urethane prepolymer (A) and the hydroxyl group-containing curing agent (B) has a mixing ratio of 0.5 to 0.8, The catalyst (C) is a titanium trialcohol aminate catalyst (C1) obtained by reacting at least a trialcoholamine and titanium tetraalkoxide, an acetic acid metal salt catalyst (C2), and an amino alcohol catalyst (C3). Using different types of catalysts, the content of each catalyst with respect to the entire forming composition is (C1): 50 to 500 ppm, (C2): 20 to 100 ppm, and (C3): 50 to 600 ppm. , A quick-release cast urethane elastomer-forming composition.

［一般式（１）中のＲ１〜Ｒ４のうち少なくとも１つが一般式（２）で示される官能基であり、残りが炭素数１〜８のアルキル基であり、一般式（２）中のＲ５が炭素数１〜４のアルキレン基である。］
(2) A rapid demolding cast urethane elastomer-forming composition , characterized in that the catalyst (C1) according to (1) is represented by the general formula (1).

[At least one of R1 to R4 in the general formula (1) is a functional group represented by the general formula (2), the rest is an alkyl group having 1 to 8 carbon atoms, and R5 in the general formula (2) Is an alkylene group having 1 to 4 carbon atoms. ]

(3) (1) or (2) the catalyst (C1) according to, characterized by being represented by the following general formula (3), fast demold casting urethane elastomer forming compositions.

Ti (OC3H7) 2 (C6H14O3N) 2 (3)

(4) The isocyanate group-containing prepolymer (A) is obtained by reaction of at least diphenylmethane diisocyanate (A1) and a bifunctional polyol (A2) having a number average molecular weight of 500 to 3,000. according to claims 1 to 3, fast demolded casting urethane elastomer forming compositions.

(5) The hydroxyl group-containing curing agent (B) uses two types of hydroxyl group-containing compounds: a short chain diol (B1) having a number average molecular weight of 300 or less and a short chain triol (B2) having a number average molecular weight of 500 or less. lying, according to any one of claims 1 to 4, wherein, wherein, fast demolded casting urethane elastomer forming compositions.

(6) The bifunctional of the hydroxyl group-containing curing agent (B) is a short chain diol (B1) having a number average molecular weight of 300 or less, a short chain triol (B2) having a number average molecular weight of 500 or less, and a number average molecular weight of 500 to 3,000. three things are those with hydroxyl group-containing compound, according to any one of claims 1 5, characterized in, quick demoulding casting urethane elastomer forming composition of the polyol (B3).

(7) The quick-release cast urethane elastomer-forming composition with small hardness creep according to any one of (1) to (6), an isocyanate group-containing urethane prepolymer (A), and a hydroxyl group-containing curing agent A method for producing a thermosetting urethane elastomer , which is obtained by injecting a liquid material in which (B) and the catalyst (C) are mixed into a mold and heat-curing, and then demolding the cured product.

The molded product obtained from the quick-release cast urethane elastomer-forming composition of the present invention can further shorten the molding cycle and shorten the curing time as compared with the conventionally known thermosetting polyurethane elastomer, While having various performances desired as parts for industrial equipment, hardness creep is remarkably improved as compared with conventionally known thermosetting polyurethane elastomer moldings.
The molded product according to the present invention can further shorten the molding cycle and shorten the curing time as compared with conventionally known thermosetting polyurethane elastomers, and also has various performances desired as parts of conventionally known industrial equipment. However, the contamination due to blooms has been improved.

  The thermosetting polyurethane elastomer-forming composition of the present invention comprises an isocyanate group-containing (hereinafter abbreviated as “NCO group”) urethane prepolymer (A), a hydroxyl group-containing curing agent (B), and a catalyst (C). In the elastomer production method in which the liquid material is poured into a mold and cured by heating, and then the cured product is demolded, the mixing ratio (functional group) of the isocyanate group-terminated urethane prepolymer (A) and the hydroxyl group-terminated curing agent (B) Ratio), hydroxyl group (mol) / NCO group (mol) = 0.5 to 0.8, and at least the catalyst (C) is titanium triethanolamate (C1) and metal acetate catalyst (C2). And an amino alcohol catalyst (C3).

  The NCO group-containing urethane prepolymer (A) used in the present invention comprises at least an aromatic diisocyanate (A1), a polyol (A2) and, if necessary, a chain extender, a reaction temperature: 50 to 100 ° C., a reaction time. : Obtained by a production method under reaction conditions of 1 to 5 hours. The NCO content of the NCO group-containing urethane prepolymer (A) is preferably 5.0 to 25.0 mass%. When the NCO content is lower than 5.0%, the viscosity of the prepolymer is mainly increased, and the flowability of the urethane resin is remarkably deteriorated during casting. If it is higher than 25.0%, the stability of properties during storage and use will be significantly deteriorated, resulting in problems such as difficulty in obtaining stable industrial equipment parts and molding defects. This is not suitable as a urethane prepolymer for molds.

  Examples of the aromatic diisocyanate (A1) include tolylene diisocyanate (TDI), phenylene diisocyanate (MDI), tolidine diisocyanate (TODI), naphthalene diisocyanate (NDI), xylene isocyanate (XDI), various isomers, Carbodiimidized, uretoniminated MDI and the like can also be used. Among these, TDI is preferable and MDI is particularly preferable.

  Examples of the polyol (A2) include polyether-based polyols, polyester-based polyols, and polycarbonate-based polyols. The number average molecular weight of the polyol (A2) is preferably 500 to 3,000, particularly preferably 750 to 2,000. The number of functional groups is preferably 2 to 4, and particularly preferably 2 to 2.5.

  Polyether-based polyols include poly (ethylene ether) glycol, poly (propylene ether) glycol and poly (tetramethylene ether) glycol (hereinafter abbreviated as PTMG), ethylene glycol, 1,3-butanediol, 1, 4-BD, diethylene glycol, dipropylene glycol, 1,2-propylene glycol, short-chain diols such as 1,3-propylene glycol, etc., or chain-triols such as glycerin and trimethylolpropane as initiators, ethylene oxide, propylene oxide , Polyether produced by ring-opening polymerization of cyclic ethers such as trimethylene oxide and tetrahydrofuran. A mixture of the above-mentioned polyethers can also be used.

  Although it does not restrict | limit especially as a polyester polyol, The adipate type polyester manufactured by polycondensing short-chain diols, such as ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, diethylene glycol, and adipic acid Examples of the polyol include polyethylene adipate, polypropylene adipate, polybutylene adipate, polypentane adipate, polyhexamethylene adipate, and diethylene adipate. If necessary, a polyfunctional product obtained by introducing a triol such as glycene or trimethylolpropane can also be used. In addition, copolyester polyols produced by polycondensation of two or more kinds of probe diols and adipic acid, such as polyethylene butylene adipate, polyethylene hexalene adipate, polydiethylene butylene adipate, polydiethylene xalene adipate, and polybutylene hexa Examples include len adipate and polyethylene butylene hexane adipate, but the combination of short chain diols is not limited. Examples of other polyester polyols are produced by polycondensation of caprolactone and / or dicarboxylic acid, such as succinic acid, malonic acid, pimelic acid, sebacic acid and suberic acid, with the above-mentioned short chain glycol, short chain triol, etc. Including those that are made. A mixture of the above polyesters can also be used.

  Examples of the polycarbonate polyol include those obtained by polycondensation from the short chain diol described above and a low molecular carbonate such as diphenyl carbonate, diethyl carbonate, or ethylene carbonate. A mixture of the above polycarbonates can also be used.

  If necessary, a short chain diol can be used as it is as a chain extender.

  The hydroxyl group-containing curing agent used in the present invention is preferably a diol (B1) having a number average molecular weight of 300 or less and a triol (B2) having a number average molecular weight of 500 or less. Moreover, what added the bifunctional polyol (B3) of number average molecular weight 500-3,000 is also preferable.

  As the short-chain diol (B1) having a number average molecular weight of 300 or less, ethylene glycol, diethylene glycol, propylene glycol, 1,4-BD, 1,3-butanediol, 1,6-hexanediol, neopentyl glycol, hydrogenated bisphenol A Etc. In the present invention, 1,4-BD is particularly preferable.

  Examples of the short chain triol (B2) having a number average molecular weight of 500 or less include glycerin, TMP, and hexanetriol. In the present invention, TMP is particularly preferred.

  As the bifunctional polyol (B3) having a number average molecular weight of 500 to 3,000, those mentioned in the above (A2) can be used.

The mass ratio of the short chain diol and the short chain triol preferred in the present invention is in the range of 50/50 to 90/10. When the ratio of the short-chain diol is less than 50, there is a problem that the tensile strength and the elongation rate are extremely lowered, and when it exceeds 90, a problem occurs that the compression set and the tensile set are deteriorated.
The mass ratio of the short-chain polyol (total amount of short-chain diol and short-chain triol) and the bifunctional polyol is in the range of 100/0 to 5/95.

  The catalyst (C) used in the present invention includes at least a titanium trialcoholaminate catalyst (C1) obtained by reacting a trialcoholamine and titanium tetraalkoxide, an acetic acid metal salt catalyst (C2), and an amino alcohol system. Three types of catalysts (C3) are used.

［一般式（１）中のＲ１〜Ｒ４のうち少なくとも１つが一般式（２）で示される官能基であり、残りが炭素数１〜８のアルキル基であり、一般式（２）中のＲ５が炭素数１〜４のアルキレン基である。］

Ｔｉ（ＯＣ３Ｈ７）２（Ｃ６Ｈ１４Ｏ３Ｎ）２ （３）
(C1) is preferably a titanium trialcohol aminate catalyst obtained by reacting a trialcoholamine using an alcohol having 1 to 4 carbon atoms with a titanium tetraalkoxide having an alkoxy group having 1 to 8 carbon atoms. Moreover, what is represented by the following general formula (1) is more preferable, and what is represented by the following general formula (3) is most preferable. Examples of the catalyst include a commercially available titanium triethanolamate / 2-propanol solution, trade name ORGATICS TC-400 (manufactured by Matsumoto Fine Chemical), and the like.

[At least one of R1 to R4 in the general formula (1) is a functional group represented by the general formula (2), the rest is an alkyl group having 1 to 8 carbon atoms, and R5 in the general formula (2) Is an alkylene group having 1 to 4 carbon atoms. ]

Ti (OC3H7) 2 (C6H14O3N) 2 (3)

  Examples of the metal acetate salt catalyst (C2) include potassium acetate and sodium acetate commercially available as reagents, potassium acetate / ethylene glycol solution as a catalyst, trade name DABCO P-15 (manufactured by Sankyo Air Products), and the like. .

  As the amino alcohol catalyst (C3), commercially available N, N, N′-trimethyl-2-hydroxylpropylenediamine, N, N-dimethylaminoethoxyethoxyethanol, N, N-dimethylaminohexanol, N, N -Dimethylaminoethoxyethanol, N-methyl-N'-hydroxylpiperazine, N, N, N'-trimethylaminoethylethanolamine and the like.

  In this invention, the usage-amount of catalyst component (C1)-(C3) is (C1); 50-500 ppm, (C2); 20-100 ppm, (C3); 50-600 ppm with respect to the whole forming composition. In particular, (C1); 60 to 400 ppm, (C2); 30 to 80 ppm, (C3); 60 to 500 ppm are preferable. The addition ratio of (C1), (C2), and (C3) is preferably 1: 1: 5 to 3: 1: 10.

  When the addition amount of (C1) is less than the lower limit, the isocyanurate-forming (NCO group trimerization) reaction formed by the catalytic effect of (C2) is prioritized, and the isocyanurate / urethane bond formation ratio is lost. Increasing the isocyanurate bond generation ratio increases the hardness creep, making it unsuitable as a thermosetting polyurethane elastomer for industrial equipment parts. On the other hand, when the upper limit is exceeded, the curing reaction becomes excessive, an abrupt increase in viscosity is observed, the flowability to the mold becomes poor, and molding defects tend to occur.

  When the amount of addition of (C2) is less than the lower limit, the progress of the isocyanurate reaction becomes insufficient, and the demolding time becomes longer, leading to a decrease in production efficiency, as well as desired physical properties, particularly high initial The modulus cannot be obtained. Conversely, when the upper limit is exceeded, the balance of isocyanurate / urethane bond formation ratio is lost and the isocyanurate bond formation ratio increases, so that the hardness creep increases, so it is not suitable as a thermosetting polyurethane elastomer for industrial equipment parts. End up. In addition, the curing reaction becomes excessive, a sudden increase in viscosity is observed, the flowability to the mold becomes poor, and molding defects tend to occur.

  When the amount of (C3) added is less than the lower limit, the rate of hardness increase after demolding becomes slow, and the curing time until the reaction is completed becomes long. On the other hand, when the upper limit is exceeded, the catalyst (C3) from the molded product blooms and contamination of industrial equipment is likely to occur.

In the present invention, the mixing ratio α (hydroxyl group (mol) / NCO group (mol)) of the NCO group-containing urethane prepolymer (A) and the hydroxyl group-containing curing agent (B) is preferably 0.5 to 0.8, particularly 0. .55 to 0.75 is preferred.
When the hydroxyl group (mol) / NCO group (mol) is less than the lower limit, the amount of isocyanurate bonds formed is excessive, resulting in a decrease in physical properties, particularly a decrease in tear strength, and is not suitable as a thermosetting polyurethane elastomer for industrial equipment parts. End up. On the other hand, when the upper limit is exceeded, sufficient mechanical strength, in particular, the initial modulus is lowered, and it becomes unsuitable as a thermosetting polyurethane elastomer for industrial equipment parts.

  In addition, the thermosetting polyurethane elastomer forming composition of this invention can use antioxidant, a defoaming agent, a ultraviolet absorber, a reaction regulator etc. as an additive collectively as needed.

  Next, the manufacturing method of the thermosetting polyurethane elastomer molding of this invention is described.

The thermosetting polyurethane elastomer formed product obtainable by the present invention is produced by mechanical molding using a casting machine or the like, molding by hand stirring, or the like. For example, it manufactures like the following 1st processes-4th processes.
First step:
The NCO group-containing prepolymer (A) is charged into the A-series tank of a two-component urethane casting machine, and the temperature is kept at 20 to 90 ° C. A hydroxyl group-containing curing agent (B) and a catalyst (C) are charged into a B-series tank of a two-component urethane casting machine at a predetermined ratio and mixed uniformly to keep the temperature at 20 to 90 ° C. Thereafter, the content liquid is vacuum degassed to prepare the discharge amounts of the A and B systems and prepare for casting.
Second step;
The liquid mixture that is mixed and discharged from the casting machine at a predetermined ratio is poured into a mold that is temperature-controlled at 60 to 150 ° C.
Third step;
When the green strength has been obtained so that the injected product can be removed from the mold, the cured product is removed from the mold. In the present invention, the time from injection to demolding can be about 0.5 to 5 minutes.
The fourth step;
The demolded molding is cured for about a week at room temperature, further processed as industrial equipment parts, and incorporated into industrial equipment as parts. In the present invention, it is possible to move to the next step after curing for about one day.

  Subsequently, according to the prescription (blending ratio) shown in Table 1 below, the mixture of the main agent (A), the curing agent (B) and the catalyst is mixed with a two-component mixed urethane casting machine, thereby forming the polyurethane elastomer of the present invention. The present invention is prepared by preparing a composition, pouring the composition into a mold for forming a 2 mm thick flat sheet preheated to 130 ° C., and heat-curing at 130 ° C. for 0.5 to 5 minutes. A polyurethane elastomer molded product was produced, and the molded product was taken out of the mold.

  The present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited thereto. In Examples and Comparative Examples, “part” means “part by mass”, and “%” means “% by mass”.

(Examples 1-4)
MDI and various polyols were mixed at the blending ratio shown in Table 1, and reacted at 75 ° C. for 3 hours to obtain various NCO group-containing urethane prepolymers (A). The results are shown in Table 1.

  With the blending ratio shown in Table 1, 1.4-BD, TMP, and various polyols were mixed at 75 ° C. for 1 hour to prepare a hydroxyl group-containing curing agent (B). Thereafter, various catalysts (C) were added so that the contents in the system shown in Table 1 were added, mixed at 75 ° C. for 1 hour, and a catalyst-containing hydroxyl group-containing curing agent ((B) + (C) added with the catalyst. )

  Then, according to the prescription (blending ratio) shown in Table 1 below, the NCO group-containing urethane prepolymer (A) and the catalyst-containing hydroxyl group-containing curing agent ((B) + (C)) are mixed with a two-component mixed urethane casting machine. By mixing, the polyurethane elastomer-forming composition of the present invention is prepared, and this composition is poured into a mold for forming a flat sheet having a thickness of 2 mm preheated to 130 ° C., and a predetermined demolding time is obtained. In the meantime, it was cured by heating in a mold, and this molded product was quickly taken out from the mold (demolded) to obtain a sheet-like polyurethane elastomer molded product.

(Comparative Example 1)
Various NCO group-containing urethane prepolymers (A) and catalyst-containing hydroxyl group-containing curing agents ((B) + (C)) were obtained in the same mixing ratio as shown in Table 1. Next, polyurethane elastomer molding was attempted in the same manner as in the examples, but in this example, the amount of catalyst (C2) added was below the lower limit, and a curing reaction until demolding was obtained even at 130 ° C. for 20 minutes. In addition, a sheet capable of measuring physical properties could not be obtained.

Comparative Example 2
Various NCO group-containing urethane prepolymers (A) and catalyst-containing hydroxyl group-containing curing agents ((B) + (C)) were obtained in the same mixing ratio as shown in Table 1. Next, polyurethane elastomer molding was attempted in the same manner as in the example, but this was an example in which the amount of the catalyst (C2) added exceeded the upper limit. The mixed liquid did not flow over the entire mold, and the urethane resin was present on the upper part of the mold. As a result, it was impossible to obtain a sheet capable of measuring physical properties of tensile properties.

Comparative Example 3
Various NCO group-containing urethane prepolymers (A) and catalyst-containing hydroxyl group-containing curing agents ((B) + (C)) were obtained in the same mixing ratio as shown in Table 1. Next, polyurethane elastomer molding was attempted in the same manner as in the examples, but in this example, the amount of catalyst (C1) added was below the lower limit, and the amount of isocyanurate produced increased and hardness creep was observed.

Comparative Example 4
Various NCO group-containing urethane prepolymers (A) and catalyst-containing hydroxyl group-containing curing agents ((B) + (C)) were obtained in the same mixing ratio as shown in Table 1. Next, polyurethane elastomer molding was attempted in the same manner as in the examples, but this was an example in which the amount of catalyst (C1) added exceeded the upper limit, and the mixed liquid did not flow throughout the mold, and the urethane resin was placed in the middle of the mold. As a result, the flowability was slightly inferior.

Comparative Example 5
Various NCO group-containing urethane prepolymers (A) and catalyst-containing hydroxyl group-containing curing agents ((B) + (C)) were obtained in the same mixing ratio as shown in Table 1. Next, polyurethane elastomer molding was attempted in the same manner as in the examples, but this was an example in which the amount of catalyst (C3) added was below the lower limit, resulting in a slow hardness development after demolding.

Comparative Example 6
Various NCO group-containing urethane prepolymers (A) and catalyst-containing hydroxyl group-containing curing agents ((B) + (C)) were obtained in the same mixing ratio as shown in Table 1. Next, polyurethane elastomer molding was attempted in the same manner as in the example, but this was an example where the amount of the catalyst (C3) added exceeded the upper limit, and the contamination was somewhat poor.

Comparative Example 7
Various NCO group-containing urethane prepolymers (A) and catalyst-containing hydroxyl group-containing curing agents ((B) + (C)) were obtained in the same mixing ratio as shown in Table 1. Next, polyurethane elastomer molding was attempted in the same manner as in the example, but this was an example in which TEDA was used without using the catalyst (C3), resulting in poor contamination.

Comparative Example 8
Various NCO group-containing urethane prepolymers (A) and catalyst-containing hydroxyl group-containing curing agents ((B) + (C)) were obtained in the same mixing ratio as shown in Table 1. Next, polyurethane elastomer molding was attempted in the same manner as in the example, but this was an example in which DOTDL was used without using the catalysts (C1) and (C3), resulting in poor flowability. Urethane resin remains on the upper part of the mold, and it was not possible to obtain a sheet capable of measuring physical properties of tensile properties.

Comparative Example 9
Various NCO group-containing urethane prepolymers (A) and catalyst-containing hydroxyl group-containing curing agents ((B) + (C)) were obtained in the same mixing ratio as shown in Table 1. Next, polyurethane elastomer molding was attempted in the same manner as in the examples, but this was an example in which the blending ratio [hydroxyl group (mol) / NCO group (mol)] was below the lower limit, and the amount of isocyanurate produced increased, The results were poor in strength, elongation and hardness creep.

Comparative Example 10
Various NCO group-containing urethane prepolymers (A) and catalyst-containing hydroxyl group-containing curing agents ((B) + (C)) were obtained in the same mixing ratio as shown in Table 1. Next, polyurethane elastomer molding was attempted in the same manner as in the examples, but this was an example in which the blending ratio [hydroxyl group (mol) / NCO group (mol)] exceeded the upper limit, and the amount of isocyanurate produced was reduced, and the initial modulus was reduced. Was inferior.

  Various measurements were carried out in the following manner using the polyurethane elastomer moldings (2 mm thick sheets) obtained from Examples 1 to 4 and Comparative Examples 1 to 10 obtained by blending and molding shown in Table 1. The results are shown in Table 1.

[Castability]
When the polyurethane elastomer-forming composition mixed and discharged by the two-component mixed urethane casting machine is poured into a mold for forming a 2 mm thick flat sheet preheated to 130 ° C., it sufficiently flows into the mold. Judgment was made according to the following criteria from the shape of the molded product obtained. The standard of evaluation is that it flows into the whole area according to the shape of the mold; ○, there is a part that does not flow more than half; △, half does not flow; ×

[Demolding time]
After injecting the polyurethane elastomer-forming composition mixed and discharged by a two-component mixed urethane casting machine into a mold for forming a 2 mm thick flat sheet preheated to 130 ° C., 1.0, 2.0, Demolding is attempted at intervals of 3.0, 5.0, 10, and 20 minutes, and the time during which demolding can be performed without deformation of the molded product is shown. The following items were tested on the polyurethane elastomer moldings obtained at this time.

[Hardness during mold removal]
After demolding the polyurethane elastomer molded product that has been heat-cured for a specified time, the molded product is quickly transferred (about 3 minutes) to a room at 23 ° C, 60% humidity and constant temperature and humidity. (MICRO HARDNESS TESTER; manufactured by Wallace) was used to measure the demolding hardness.

[Time hardness (next day, two days later, three days later, seven days later (final hardness))]
Subsequently, the obtained molded product was measured for IRHD hardness manufactured by Wallace at a predetermined time with a sheet cured in a room at a constant temperature and high humidity of room temperature 23 degrees and humidity 60%. . A material with a rapid increase in hardness has a high speed to the final reaction and is excellent in mass productivity, and was used as an index.

[Initial modulus, tensile strength, elongation ratio]
Using a sheet that had been cured for 7 days in a room at a constant temperature and high humidity of 23 ° C. and 60% humidity, the initial modulus, tensile strength, and elongation rate were measured according to JIS K7312.

[Hardness creep]
Hardness creep was measured on a sheet that had been cured for 7 days in a room at a constant temperature and high humidity of room temperature 23 degrees and humidity 60%. For the measurement, an IRHD hardness tester (Digitest; manufactured by H. Burreis, Germany) was used, and the initial hardness value and the rate of change in hardness after 99 seconds were obtained from the following equation.
Hardness creep (%) = (initial value hardness−99 second value hardness) / initial hardness × 100

[Contamination]
A contamination test was conducted on a sheet that had been cured for 7 days in a room at a constant temperature and high humidity of room temperature 23 degrees and humidity 60%. In the test, a molded sheet was cut into a square of 50 × 50 × 2 mm, sandwiched between two clean glass plates, prepared with a weight so as to be a load of 0.1 kg / cm 2, under conditions of a temperature of 60 ° C. and a humidity of 80%. The molded sheet was peeled off for 1 week and then peeled off. The glass was soiled and visually judged according to the following criteria. Evaluation criteria are as follows: No dirt; ○, Slightly dirty; △, Dirt; ×

[Isocyanurate bond / urethane bond IR absorbance ratio]
Tests were conducted for the isocyanurate-bonded / urethane-bonded IR absorbance ratio on a sheet that had been cured for 7 days in a room at a constant temperature and humidity of 23 ° C. and 60% humidity. Tests, FT-IR; was measured in the sheet cross section by ATR method (Avatar 360 manufactured by Nicolet), the absorbance ratio of isocyanurate linkages 1415cm ^-1 / urethane bond 1530 cm ^-1, a comparison of generation ratio of isocyanurate bond went. When this value is large, the hardness coup tends to be large.

In Table 1, MDI; 4,4′-diphenylmethane diisocyanate TDI; 2,4-toluene diisocyanate PBA-750; polyester diol obtained from 1,4-butanediol and adipic acid, number average molecular weight = 750
PEA-2000; polyester diol obtained from ethylene glycol and adipic acid, number average molecular weight = 2,000
PBA-2500; polyester diol obtained from 1,4-butanediol and adipic acid, number average molecular weight = 2,500
PTMG-1000; poly (oxytetramethylene) glycol, number average molecular weight = 1,000
ORGATICS TC-400; 2-propanol solution of titanium triethanolamate (solid content: about 80%) (Matsumoto Fine Chemical)
DABCO P-15; Ethylene glycol diluted solution of potassium acetate (solid content: about 38.4%) (manufactured by Sankyo Air Products)
POLYCAT 17; N, N, N′-trimethyl-2-hydroxyethylpropylenediamine (manufactured by Air Products Japan)
TEDA: Triethylenediamine (Tosoh)
DOTDL: Dioctyltin dilaurate (manufactured by Kyodo Yakuhin)

According to the catalyst composition of the present invention, the thermosetting polyurethane elastomer constituting the molded product having the above-mentioned mechanical properties can be reliably molded by mixing and reaction of the NCO group-containing prepolymer and the hydroxyl group-containing curing agent. it can.

Claims (7)

The mixing ratio α (hydroxyl group (mol) / NCO group (mol)) of the isocyanate group-containing urethane prepolymer (A) and the hydroxyl group-containing curing agent (B) has a mixing ratio of 0.5 to 0.8. ) At least three types of catalysts: a titanium trialcohol aminate catalyst (C1) obtained by reacting a trialcoholamine and titanium tetraalkoxide, a metal acetate catalyst (C2), and an amino alcohol catalyst (C3). is the content for the reference, the entire forming composition of each catalyst (C1): 50~500ppm, (C2 ): 20~100ppm, (C3): and it is 50～600Ppm, wherein, Hayada' Mold cast urethane elastomer forming composition. The catalyst (C1) of Claim 1 is represented by General formula (1) , The quick demolding cast urethane elastomer formation composition characterized by the above -mentioned.

[At least one of R1 to R4 in the general formula (1) is a functional group represented by the general formula (2), the rest is an alkyl group having 1 to 8 carbon atoms, and R5 in the general formula (2) Is an alkylene group having 1 to 4 carbon atoms. ] The catalyst (C1) according to claim 1 or 2 is represented by the following general formula (3), a rapid demolding cast urethane elastomer-forming composition.

Ti (OC3H7) 2 (C6H14O3N) 2 (3) The isocyanate group-containing prepolymer (A) is obtained by a reaction of at least diphenylmethane diisocyanate (A1) and a bifunctional polyol (A2) having a number average molecular weight of 500 to 3,000. according to 1 to 3, fast demold casting urethane elastomer forming compositions. The hydroxyl group-containing curing agent (B) is one using at least two types of hydroxyl group-containing compounds: a short chain diol (B1) having a number average molecular weight of 300 or less and a short chain triol (B2) having a number average molecular weight of 500 or less, according to any one of claims 1 to 4, wherein, wherein, fast demolded casting urethane elastomer forming compositions. The hydroxyl group-containing curing agent (B) is at least a short chain diol (B1) having a number average molecular weight of 300 or less, a short chain triol (B2) having a number average molecular weight of 500 or less, a bifunctional polyol (B3) having a number average molecular weight of 500 to 3,000. 6) The three-hydroxyl group-containing compound is used , and the rapidly demolding cast urethane elastomer-forming composition according to any one of claims 1 to 5. A quick-release cast urethane elastomer-forming composition with small hardness creep according to any one of claims 1 to 6, an isocyanate group-containing urethane prepolymer (A), a hydroxyl group-containing curing agent (B), catalyst (C) and the combined liquid was cured by heating is injected into the mold, after which the resulting cured product was demolded, method for producing a thermoset urethane elastomer.