JP3376780B2 - Two-component polyurethane elastomer composition for casting and method for producing polyurethane elastomer - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a two-component casting polyurethane elastomer composition and a method for producing a polyurethane elastomer. More specifically, the present invention relates to a two-component casting polyurethane elastomer composition comprising a polyester-based isocyanate group-terminated prepolymer and a specific polyol mixture as a curing agent, which has excellent physical strength and weather resistance.

[0002]

2. Description of the Related Art Generally, a polyurethane elastomer for casting is prepared, for example, by reacting tolylene diisocyanate with a polyol to obtain an NCO group-terminated prepolymer, and then 4,4'-methylenebis (2-chloroaniline), 4 , 4'-diaminodiphenylmethane, 4,4 '
-Diaminodiphenyl ether or the like is used. Polyurethane elastomers obtained using such a composition have discoloration due to light due to aromatic polyisocyanate, while amine as a curing agent is caused by contact with air due to insufficient storage and handling. Oxidation and decomposition by heating and melting proceeded to increase the degree of coloring, which greatly affected the color tone and the degree of coloring of the molded product, limiting its use. JP 6-3
In JP 06141, dicyclohexylmethane diisocyanate (hereinafter, abbreviated as hydrogenated MDI) is used as a part of polyisocyanate and reacted with a polyether polyol to give an NCO group-terminated prepolymer. The present invention aims to improve workability and obtain excellent physical properties, but has not yet improved weather resistance.

[0003]

DISCLOSURE OF THE INVENTION The inventors of the present invention have made extensive studies in the conventional casting technique to improve weather resistance, and as a result, as a polyisocyanate for a polyester NCO group-terminated prepolymer, , Hexamethylene diiso
Cyanate isocyanurate ring-containing modified product (hereinafter referred to as H
Abbreviated as DI) and hydrogenated MDI , or
Arrangement of uretdione rings of hexamethylene diisocyanate
Isocyanurate ring-containing modified product (hereinafter referred to as HDI
Abbreviated todion ring-nurate ring-containing modified product) and hydrogenated MD
The present invention has been found to be improved by using a polyester-based NCO group-terminated prepolymer component composed of I and a polyester polyol, and a specific polyol mixture as a curing agent, and has arrived at the present invention.

[0004]

That is, the present invention relates to a polyurethane elastomer composition which comprises (A) a modification of HDI.
Polyester-based NCO group-terminated prepolymer component composed of a polymer , hydrogenated MDI, and polyester polyol, and (B) 1,4-bis (2-hydroxyethoxy) benzene (hereinafter, abbreviated as BHEB) as a curing agent and tri A two-component casting polyurethane elastomer composition comprising methylolpropane (hereinafter abbreviated as TMP). The present invention provides a polyurethane elastomer composition containing (A) HDI uretdione ring and nurate ring.
A two-component polyurethane elastomer composition for casting, characterized by comprising a modified product and hydrogenated MDI, a polyester-based isocyanate group-terminated prepolymer component comprising a polyester polyol, and (B) a curing agent BHEB and TMP. Is. The present invention uses a two-component casting polyurethane elastomer composition and mixes and agitates the component (A) and the component (B) at an NCO group / active hydrogen group molar ratio of 0.8 to 1.2 to form a mold. A method for producing a polyurethane elastomer, which comprises injecting and molding.

As the polyisocyanate constituting the polyester type NCO group-terminated prepolymer which is the component (A) of the present invention , modified HDI and hydrogenated MDI or HD are used.
Modified product containing uretdione ring and nurate ring of I and hydrogenated MD
I is used together. Other polyisocyanates that can be used with hydrogenated MDI include isophorone diisocyanate, xylylene diisocyanate, lysine diisocyanate,
Examples thereof include tetramethylxylylene diisocyanate and the like and modified products thereof. These may be used alone or as a mixture of two or more. Also UDI of HDI
The ring-containing compound and hydrogenated MDI can also be used in combination. The use ratio of such polyisocyanate is such that the modified product of HDI or HD is based on 100 parts by weight of hydrogenated MDI.
The uretdione ring-nurate ring-containing modified product of I
0 parts by weight. Preferably, 35 to 360 parts by weight of the HDI modified product or the HDI uretdione ring-nurate ring-containing modified product is used with respect to 100 parts by weight of hydrogenated MDI.

The modified HDI constituting the component (A) of the present invention is hexamethylene diisocyanate (hereinafter referred to as HDI).
Abbreviated as ") or an HDI polyol adduct obtained by adding a part of the NCO group of HDI to a polyol, and adding an isocyanurate-forming catalyst and, if necessary, a cocatalyst to about 50-10
It can be obtained by carrying out an isocyanurate-forming reaction at 0 ° C. In this case, 20% by weight of the NCO group of HDI
The following is reacted with a polyol to obtain a polyol adduct of HDI. The polyol for obtaining the polyol adduct of HDI has a molecular weight of 3000 or less and a functionality of 2 to 3, such as 1,3-butanediol, dipropylene glycol, 1,6-hexane glycol,
3-methyl-1,5-pentanediol, neopentyl glycol (hereinafter abbreviated as NPG), 2,2-diethyl-1,3-propanediol, 2-ethyl-1,3-hexanediol, 2-n- Butyl-2-ethyl-1,3
-Propane diol (hereinafter abbreviated as 2-BEPG), polyester polyol, polyether polyol, and the like. These can be used alone or as a mixture of two or more kinds.

As a catalyst for obtaining a modified product of HDI, propionic acid, butyric acid, valeric acid, caproic acid, heptanoic acid, caprylic acid, pelargonic acid, capric acid, undecylic acid and potassium or sodium salts of these branched fatty acids are used. Is mentioned. As a cocatalyst that can be used in combination with the catalyst, a phenolic hydroxy compound (phenol, cresol, etc.), an alcoholic hydroxy compound (ethanol, cyclohexanol, etc.), or a tertiary amine (triethylamine, methylpiperidine, etc.) is used. be able to. The reaction easily proceeds with this promoter. The amount of the catalyst used is 0.001 to 0.25% by weight based on the polyisocyanate, and the cocatalyst is 0.01 to 0.25% by weight.
It is 0.2% by weight. A reaction terminator can also be used. As the terminating agent, for example, phosphoric acid, sulfuric acid or the like can be used, and the amount used is 0.5 to 5.0 times the catalyst equivalent.

The uretdione ring-nurate ring-containing modified product of HDI used in the present invention is HDI or NC of HDI.
It is obtained by converting a part of the O groups into a polyol adduct, if necessary, and then converting it to an isocyanurate. This polyol adduct of HDI is obtained by converting a part (20% by weight or less) of all NCO groups into a polyol adduct and then converting it into uretdione and isocyanurate. As the polyol that can be used here, the polyol used when obtaining the HDI modified product can be used. As an effective catalyst for obtaining a modified product of HDI containing uretdione ring and nurate ring, triethylphosphine, dibutylethylphosphine, tri-
Examples thereof include phosphines such as n-propylphosphine, trioctylphosphine, and triamylphosphine. The reaction can be carried out in the same manner as the isocyanurate formation. The reaction mixture thus obtained is obtained by removing unreacted HDI, for example by thin film distillation.
The uretdione ring-nurate ring-containing modified form of HDI has a ratio of the isouanurate cyclic trimer content of 11 to 40% by weight to the uretdione dimer content of 20 to 60% by weight. The NCO group content is 17 to 25% by weight. The uretdione dimer content and the isouanurate cyclic trimer content were determined from a calibration curve based on the area percentage of each peak obtained by gel permeation chromatography with a differential refractometer detection.

As described above, the modified product of HDI and the modified product of uretdione ring-nurate ring of HDI are allowed to easily undergo isocyanurate formation, uretdione formation and isocyanurate formation reaction by adding a polyol to HDI. Become. Further, by using such a polyisocyanate as a part of the component, the compatibility of the entire component for obtaining the elastomer is improved, and a molded product exhibiting more excellent performance can be obtained.

The preferred polyisocyanate used to obtain the component (A) of the present invention is HDI
And compounds containing isocyanurate ring
And hydrogenated MDI together, or by adding polyol to HDI
Uretdione ring and isocyanurate ring
And a hydrogenated MDI in combination.

As the polyester polyol constituting the polyester type isocyanate group-terminated prepolymer which is the component (A) of the present invention, ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol and 3-methyl are used. -1,5-pentanediol, 1,6-hexanediol, neopentyl glycol (hereinafter abbreviated as NPG), diethylene glycol,
One or more of 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, decamethylene glycol, etc., and malonic acid, maleic acid, succinic acid, adipic acid, glutaric acid, pimelic acid, sebacic acid, shu Examples thereof include polyester polyols containing one or more of acids, phthalic acid, isophthalic acid, terephthalic acid, and hexahydrophthalic acid, and polycaprolactone polyols obtained by ring-opening polymerization of lactones. A preferred polyester polyol is a poly (ethylene adipate) diol having a hydroxy end group having a molecular weight of 800 to 3500, preferably 1000 to 3000.

The polyester-based NCO group-terminated prepolymer, which is the component (A) of the present invention, is produced at an NCO group / hydroxyl group molar ratio of 1.3 to 10.0. Preferably, it is 1.6 to 6.0. The reaction between the polyisocyanate and the polyester polyol has a reaction temperature of 50 to 1
Polyester NC at 00 ℃, reaction time 2.5 ~ 6 hours
An O group terminated prepolymer can be obtained. The NCO group content of the prepolymer is 3.0 to 8.0% by weight.

The curing agent for the component (B) of the present invention is B
Use HEB and TMP. The use ratio of BHEB and TMP is 95: 5 to 10:90 (molar ratio), preferably 90:10 to 20:80 (molar ratio). This ratio affects various properties of the elastomer such as hardness, tensile strength and compression strain. Therefore, by freely changing the ratio, an elastomer that meets the required characteristics can be obtained.

If necessary, a catalyst may be added to BHEB and TMP constituting the component (B) of the present invention. Examples of the catalyst include tertiary amines such as triethylenediamine and dimethylethanolamine, and metal compounds such as dibutyltin dilaurate.

In the component (A) and the component (B) of the present invention, the NCO group of the urethane prepolymer and the active hydrogen group concentration of the component (B) have a molar ratio of NCO group / active hydrogen group of 0.8.
~ 1.2. If necessary, reaction catalysts, additives, etc. may be used. As the casting mold, the (A) / (B) mixture is poured into a preheated mold, and primary crosslinking is performed at a temperature of 20 to 160 ° C. Next, if necessary, secondary crosslinking is carried out at 100 to 170 ° C., and after aging, a urethane elastomer is obtained. The obtained urethane elastomer can be used in various fields,
For example, it is particularly useful for rolls and tires.

[0016]

EFFECTS OF THE INVENTION The polyurethane elastomer obtained according to the present invention does not deteriorate general physical properties such as hardness, tensile strength, elongation and compression strain, and has good casting workability and heat resistance, Shows excellent performance such as weather resistance. Especially H
By containing the isocyanurate ring of DI, excellent heat resistance, weather resistance and the like can be obtained.

[0017]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. "Parts" and "%" in the examples mean "parts by weight" and "% by weight", respectively.

Reference Example 1 (Synthesis of HDI modified product) As a catalyst to 100 parts of HDI,
Using 0.1 part of potassium caprate and 0.1 part of phenol as a cocatalyst, an isocyanurate-forming reaction is carried out at 50 ° C. for 5 hours, and 0.07 part of phosphoric acid is added as a terminating agent,
The reaction was completed. Then, unreacted HDI is distilled off to remove HDI.
A modified product of NCO group content 22.0%, viscosity 195
It was 0 cPs / 25 ° C.

Reference Example 2 (Synthesis of modified HDI) 2-BEPG was added to 100 parts of HDI.
1.0 part was added and the reaction was carried out at 90 ° C. for 3 hours to obtain a polyol adduct of HDI. Next, using 0.1 part of potassium caprate and 0.1 part of phenol as a cocatalyst, the mixture was heated at 50 ° C. for 5 hours.
The isocyanurate-forming reaction was carried out for a period of time, and 0.07 part of phosphoric acid was added as a terminating agent to terminate the reaction. Next, unreacted HDI was distilled off to obtain a modified HDI. The NCO group content was 21.1% and the viscosity was 2850 cPs / 25 ° C.

Reference Example 3 (Synthesis of uretdione ring-nurate ring-containing modified product of HDI) To 300 parts of HDI, 0.3 part of triblephosphine was added and reacted at 90 ° C. for 3 hours, and 0.33 part of methyl paratoluenesulfonate as a terminating agent. Was added to terminate the reaction. Then, unreacted HDI was distilled off to obtain a modified product of HDI containing uretdione ring and nurate ring. NCO group content 22.
The viscosity was 0% and the viscosity was 100 cPs / 25 ° C. The HDI dimer content was 43% and the HDI trimer content was 31%.

Reference Example 4 (Synthesis of uretdione ring-nurate ring-containing modified product of HDI) A reaction was carried out in the same manner as in Reference Example 2 using 300 parts of HDI, 6.4 parts of NPG and 0.4 part of tributylphosphine. Methyl paratoluenesulfonate as a terminating agent
The reaction was terminated by adding 33 parts. Next unreacted HD
I was distilled off to obtain a modified product of HDI containing uretdione ring and nurate ring. NCO content 21.1%, viscosity 150 cPs / 2
It was 5 ° C. HDI dimer is 32%, HDI
Was 28%.

Examples 1 to 3 Production of Polyurethane Elastomer Composition and Elastomer As polyisocyanate, hydrogenated MDI (trade name Hiren W, manufactured by DuPont, NCO group content 31.8%, the same applies hereinafter) and HDI of Reference Example 1 were used. Modified poly (ethylene adipate) diol (average molecular weight 1500, hydroxyl value 7
4.8) to obtain an elastomer composition comprising a polyester-based NCO group-terminated prepolymer component and BHEB and TMP as a curing agent.

Production of Elastomer As polyisocyanate, hydrogenated MDI and H of Reference Example 1 were used.
The DI modified product was charged into a four-necked flask under the conditions shown in Table 1, and 5
Hold at 0 ° C. Then, poly (ethylene adipate) diol was reacted under a nitrogen stream while stirring under the conditions shown in Table 1 to obtain a transparent and viscous prepolymer (A). To the prepolymer (A) thus obtained, BHEB and TMP were added as the component (B), and the mixture was sufficiently stirred until it became completely uniform, and then defoaming was performed at a vacuum pressure of 10 Torr or less until the foaming stopped. It was 1 of this mixture
Pour into a centrifugal molding machine preheated to 30 ° C, and set the primary cure to 1
The plate-like polyurethane obtained is treated at 30 ° C. for 1 hour to give 12
After secondary cross-linking at 0 ° C. for 2 hours, it was further aged at room temperature for 1 week to obtain an elastomer. The formulations are shown in Table 1 and the results are shown in Table 1.

Examples 4 to 6 Production of Polyurethane Elastomer Composition and Elastomer As a polyisocyanate, hydrogenated MDI and H of Reference Example 2 were used.
An elastomer composition comprising a polyester NCO group-terminated prepolymer component composed of a modified DI and poly (ethylene adipate) diol (average molecular weight 3000, hydroxyl value 37.4) and BHEB and TMP as a curing agent was obtained. Production of Elastomer Hydrogenated MDI and H of Reference Example 2 as polyisocyanate
The DI modified product was charged into a four-necked flask under the conditions shown in Table 1,
Hold at 50 ° C. Then poly (ethylene adipate)
The diol was reacted under a nitrogen stream with stirring under the conditions shown in Table 1 to obtain a transparent and viscous prepolymer (A). To the prepolymer (A) thus obtained, BHEB and TMP were added as the component (B), and the mixture was sufficiently stirred until it became completely uniform, and then defoaming was performed at a vacuum pressure of 10 Torr or less until the foaming stopped. It was 1 of this mixture
Pour into a centrifugal molding machine preheated to 30 ° C, and set the primary cure to 1
The plate-like polyurethane obtained by carrying out at 30 ° C. for 1 hour
After secondary crosslinking at 20 ° C. for 2 hours, it was further aged at room temperature for 1 week to obtain an elastomer. The formulations are shown in Table 1 and the results are shown in Table 1.

Examples 7 to 8 Production of Polyurethane Elastomer Composition and Elastomer As polyisocyanate, hydrogenated MDI and H of Reference Example 3 were used.
Elastomer composition consisting of polyester-based NCO group-terminated prepolymer component consisting of DI uretdione ring-nurate ring-containing modified product and poly (ethylene adipate) diol (average molecular weight 1500, hydroxyl value 74.8) and BHEB and TMP as curing agent I got a thing.

Production of Elastomer As polyisocyanate, hydrogenated MDI and H of Reference Example 3 were used.
The uretdione ring-nurate ring-containing modified form of DI was charged into a four-necked flask under the conditions shown in Table 2 and kept at 50 ° C. Next, poly (ethylene adipate) diol was added under a nitrogen stream,
The reaction was carried out under the conditions shown in Table 2 with stirring to obtain a transparent and viscous prepolymer (A). The prepolymer (A) thus obtained contains BHEB and TM as the component (B).
After P was added and the mixture was sufficiently stirred until it became completely uniform, defoaming was performed at a reduced pressure degree of a vacuum pump of 10 Torr or less until foaming stopped. This mixed solution was poured into a centrifugal molding machine preheated to 130 ° C., primary curing was performed at 130 ° C. for 1 hour, and the obtained plate-like polyurethane was secondarily crosslinked at 120 ° C. for 2 hours, and then further cured at room temperature for 1 hour. Aged for a week to obtain an elastomer. The formulations are shown in Table 2 and the results are shown in Table 2.

Examples 9 to 10 Production of Polyurethane Elastomer Composition and Elastomer As polyisocyanate, hydrogenated MDI and H of Reference Example 4 were used.
Polyester NCO group-terminated prepolymer component consisting of DI uretdione ring-nurate ring-containing modified product and poly (ethylene adipate) diol (average molecular weight 3000, hydroxyl value 37.4), and elastomer composition comprising BHEB and TMP as a curing agent I got a thing. Production of Elastomer As polyisocyanate, hydrogenated MDI and H of Reference Example 4
The uretdione ring-nurate ring-containing modified form of DI was charged into a four-necked flask under the conditions shown in Table 2 and kept at 50 ° C. Next, poly (ethylene adipate) diol was added under a nitrogen stream,
The reaction was carried out under the conditions shown in Table 2 with stirring to obtain a transparent and viscous prepolymer (A). The prepolymer (A) thus obtained contains BHEB and TM as the component (B).
After P was added and the mixture was sufficiently stirred until it became completely uniform, defoaming was performed at a reduced pressure degree of a vacuum pump of 10 Torr or less until foaming stopped. This mixed solution was poured into a centrifugal molding machine preheated to 130 ° C., primary curing was carried out at 130 ° C. for 1 hour, and the obtained plate-like polyurethane was secondarily crosslinked at 120 ° C. for 2 hours, and then at room temperature for 1 week. Aged to obtain an elastomer. The formulations are shown in Table 2 and the results are shown in Table 2.

Comparative Example 1 Production of Elastomer Tolylene diisocyanate (hereinafter abbreviated as TDI) was used as a polyisocyanate and charged into a four-necked flask and kept at 50 ° C. Next, poly (ethylene adipate) diol (average molecular weight 1500, hydroxyl value 74.
8) was reacted under a nitrogen stream with stirring under the conditions shown in Table 3 to obtain a transparent and viscous prepolymer (A). To the prepolymer (A) thus obtained, (B)
After adding 4,4'-methylenebis (2-chloroaniline) (hereinafter, abbreviated as MOCA) as a component and stirring sufficiently until it became transparent, defoaming was performed at a vacuum pump 10 Torr or less until the foaming subsided. It was 1 of this mixture
Pour into a centrifugal molding machine preheated to 30 ° C, and set the primary cure to 1
The plate-like polyurethane obtained is treated at 30 ° C. for 1 hour to give 12
After secondary cross-linking at 0 ° C. for 2 hours, it was further aged at room temperature for 1 week to obtain an elastomer. The formulations are shown in Table 3 and the results are shown in Table 3.

Comparative Example 2 Production of Elastomer In Comparative Example 1, diphenylmethane diisocyanate (hereinafter abbreviated as MDI) was used in place of TDI, and poly (ethylene adipate) diol (average molecular weight 150) was used.
0, hydroxyl value 74.8) instead of poly (ethylene adipate) diol (average molecular weight 3000, hydroxyl value 3
7.4), an elastomer was obtained in the same manner as in Comparative Example 1 except that 1,4-butanediol was used instead of MOCA. The formulation and the results are shown in Table 3.

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

[Table 3]

[Explanation of Tables] (1) The heat-resistant sample was heated in a Gar oven at 120 ° C. for 400 hours, and then the state change was observed and evaluated in five levels. Grade 5: No change on the surface Grade 4: Little change but not noticeable Grade 3: Little change but noticeable Grade 2: Somewhat remarkable change Grade 1: Significant change (2 ) Using a weather resistant sunshine weatherometer, the temperature of the black panel was kept at 80 to 83 ° C., and after 400 hours (no rainfall condition), the discolored state of the surface was observed and evaluated in 5 grades. Grade 5: No change on the surface Grade 4: Slight change is not noticeable Grade 3: Slight change but is noticeable Grade 2: Slight change is noticeable Grade 1: Change is noticeable

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-6-316618 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08G 18/10 C08G 18 / 65-18 / 66 C08G 18/77-17/79

Claims (3)

(57) [Claims] 1. A polyurethane elastomer composition comprising: (A) isocyanurate of hexamethylene diisocyanate
Modified ring-containing ring and dicyclohexylmethane diisocyanate
Polyester NC consisting of anate and polyester polyol
A two-component casting polyurethane elastomer composition comprising an O group-terminated prepolymer component and (B) 1,4-bis (2-hydroxyethoxy) benzene and trimethylolpropane as a curing agent. 2. A polyurethane elastomer composition comprising: (A) uretdione of hexamethylene diisocyanate
Ring and isocyanurate ring-containing modified products and dicyclohexyl
Polyester NC composed of xylmethane diisocyanate and polyester polyol
A two-component casting polyurethane elastomer composition comprising an O group-terminated prepolymer component and (B) 1,4-bis (2-hydroxyethoxy) benzene and trimethylolpropane as a curing agent. 3. The two-component polyurethane elastomer composition for casting according to claim 1 or 2, wherein the component (A) and the component (B) have an NCO group / active hydrogen group molar ratio of 0.8 to.
1. A method for producing a polyurethane elastomer, which comprises mixing and stirring in 1.2, pouring the mixture into a mold, and molding.