JP2009096824A - Isocyanate prepolymer and polyurethane elastomer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To impart high biodegradability to an isocyanate prepolymer and a polyurethane elastomer without deteriorating physical properties such as mechanical strength and solvent resistance. <P>SOLUTION: Succinic acid is used as a carboxylic acid that is a raw material for a polyester polyol, and ethylene glycol and/or its oligomer are used as an alcohol component. Thereby, the polyester polyol having a low melting point, a low viscosity and high biodegradability is obtained, and the polyester polyol is used as a raw material for the polyurethane elastomer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to isocyanate prepolymers and polyurethane elastomers. In detail, it is related with the polyurethane elastomer excellent in biodegradability, mechanical strength, and solvent resistance by using specific polyester polyol and isocyanate prepolymer using the same.

  Polyurethane elastomers have excellent mechanical strength, wear resistance, low-temperature characteristics, etc., and because they offer a wide range of hardness and elasticity, various industrial equipment such as waterproofing materials, flooring materials, paving materials, adhesives, sealing materials, etc. It is used as a structural member.

  Examples of a general method for producing a polyurethane elastomer include a one-shot method and a prepolymer method. The one-shot method is a method of obtaining a polyurethane elastomer by reacting a polyisocyanate component (a), a polyol component (b), a cross-linking agent (d) and other auxiliary agents as required at a time. Since the one-shot method reacts these components at once, there is a drawback that a large amount of heat is generated during the polymerization reaction such as urethanization and stable physical properties cannot be obtained. In the prepolymer method, a polyisocyanate component (a), a polyol component (b) and other auxiliary agents as required are reacted to produce an isocyanate prepolymer (c), and then a crosslinking agent (d) and other components as required. In this method, a polyurethane elastomer is obtained by further reacting the auxiliary. On the other hand, the prepolymer method has the disadvantage that if the isocyanate prepolymer (c) has a high viscosity, defoaming is poor during molding and the molding operation becomes difficult, but it has stable physical properties compared to the one-shot method. There is a feature that a polyurethane elastomer can be obtained.

  The mechanical properties of the resulting polyurethane elastomer largely depend on the composition and structural characteristics of the polyol component (b). As the polyol component (b), polytetramethylene ether glycol (PTMG) is used for ethers, 1,4-butanediol adipate is used for esters, and polycaprolactone is used for lactones, which has a number average molecular weight of about 500 to 5,000. Used. (Japanese Patent Laid-Open No. 5-339335)

  However, these polyol components have a high melting point of about 20 to 60 ° C., and are difficult to handle because they become solid at room temperature or lower. On the other hand, when a polyol component having a relatively low viscosity is used, for example, the mechanical strength of polyurethane elastomers There is a limit to the polyol components that can be selected.

In recent years, plant-derived raw materials and biodegradable raw materials have been increasingly used due to environmental considerations and efforts, and polyurethane elastomers are also required to have improved biodegradability.
JP-A-5-339335

  An object of the present invention is to provide a polyurethane elastomer having physical properties such as mechanical strength and solvent resistance and having high biodegradability, and an isocyanate prepolymer therefor.

  As a result of intensive studies by the inventors to achieve these objects, the inventors have obtained knowledge that the above problems can be solved by using a polyester polyol having a specific structural characteristic as a raw material for a polyurethane elastomer. It came to be completed. That is, by using succinic acid as a carboxylic acid component that is a raw material of polyester polyol and using ethylene glycol and / or an oligomer thereof as an alcohol component, a polyester polyol having a low melting point, low viscosity, and high biodegradability can be obtained. By using it as a raw material for polyurethane elastomer, it was found that it has mechanical strength, solvent resistance, and high biodegradability, and the present invention was completed.

That is, this invention has the summary characterized by the following.
(1) Isocyanate prepolymer (c) obtained by reacting at least the polyisocyanate component (a) and the polyol component (b), and at least a part of the polyol component (b), the carboxylic acid component (b- In the isocyanate prepolymer (c) using the polyester polyol (b-3) obtained by reacting 1) and the alcohol component (b-2), succinic acid is used as the carboxylic acid component (b-1), and the alcohol component ( An isocyanate prepolymer (c) using ethylene glycol and / or an oligomer thereof as b-2).
(2) Isocyanate prepolymer (c) obtained by reacting at least the polyisocyanate component (a) and the polyol component (b), wherein at least part of the polyol component (b) is a carboxylic acid component (b- In the isocyanate prepolymer (c) using the polyester polyol (b-3) obtained by reacting 1) and the alcohol component (b-2), succinic acid is used as the carboxylic acid component (b-1), and the alcohol component ( Diisocyanate glycol and / or triethylene glycol is used as b-2) isocyanate prepolymer (c).
(3) Isocyanate prepolymer (c) obtained by reacting at least the polyisocyanate component (a) and the polyol component (b), and the carboxylic acid component (b-1) as the total amount of the polyol component (b) In the isocyanate prepolymer (c) using the polyester polyol (b-3) obtained by reacting the alcohol component (b-2) with succinic acid as the carboxylic acid component (b-1), the alcohol component (b- Isocyanate prepolymer (c), characterized in that diethylene glycol and / or triethylene glycol is used as 2).
(4) A polyurethane elastomer obtained by reacting at least the crosslinking agent (d) with the isocyanate prepolymer (c) according to any one of (1) to (3).
(5) A polyurethane elastomer obtained by reacting at least the polyisocyanate component (a) with the polyol component (b) and the crosslinking agent (d), wherein at least a part of the polyol component (b) is a carboxylic acid component ( In the polyurethane elastomer using the polyester polyol (b-3) obtained by reacting b-1) with the alcohol component (b-2), succinic acid is used as the carboxylic acid component (b-1), and the alcohol component (b- A polyurethane elastomer characterized by using ethylene glycol and / or an oligomer thereof as 2).
(6) A polyurethane elastomer obtained by reacting at least the polyisocyanate component (a) with the polyol component (b) and the crosslinking agent (d), wherein at least a part of the polyol component (b) is a carboxylic acid component ( In the polyurethane elastomer using the polyester polyol (b-3) obtained by reacting b-1) with the alcohol component (b-2), succinic acid is used as the carboxylic acid component (b-1), and the alcohol component (b- A polyurethane elastomer characterized by using diethylene glycol and / or triethylene glycol as 2).
(7) A polyurethane elastomer obtained by reacting at least the polyisocyanate component (a), the polyol component (b), and the crosslinking agent (d), wherein the carboxylic acid component (b- 1) In polyurethane elastomer using polyester polyol (b-3) obtained by reacting alcohol component (b-2), succinic acid is used as carboxylic acid component (b-1), and alcohol component (b-2) A polyurethane elastomer characterized in that diethylene glycol and / or triethylene glycol is used.

  According to the present invention, it has mechanical strength and solvent resistance, and can impart high biodegradability to the polyurethane elastomer.

  Hereinafter, the present invention will be described in detail. As the polyol component (b) in the present invention, a polyester polyol (b-3) obtained by reacting at least the carboxylic acid component (b-1) and the alcohol component (b-2) is used.

  In the present invention, succinic acid is used as the carboxylic acid component (b-1) which is a raw material of the polyester polyol (b-3). In addition to succinic acid, aliphatic carboxylic acids such as acetic acid, glutaric acid, adipic acid, sebacic acid, azelaic acid, malic acid, fumaric acid, maleic acid, benzoic acid, phthalic anhydride, terephthalic acid, isophthalic acid, hexa Hydrocarbonic acid, trimellitic acid, aromatic carboxylic acid such as pyromellitic acid, etc. can also be used in combination with normal carboxylic acid used in the synthesis of polyester polyol, but the desired biodegradability, mechanical strength, In order to obtain solvent resistance, it is desirable that the amount of carboxylic acid other than succinic acid is 30 mol% or less of the total carboxylic acid, and the carboxylic acid component (b-1) is entirely succinic acid. Most preferably.

  These carboxylic acid components (b-1) may be acid anhydrides such as phthalic anhydride or ester derivatives such as dimethyl succinate, and as described above, other than succinic acid. As long as the amount of carboxylic acid used is 30 mol% or less of the total carboxylic acid ratio, crude products such as those obtained in the production process of succinic acid or adipic acid, such as adipic acid, glutaric acid, succinic acid Mixtures may be used. Two or more of these acid anhydrides and ester derivatives can be used in combination.

  In this invention, ethylene glycol and / or its oligomer are used as an alcohol component (b-2) which is a raw material of polyester polyol (b-3). Specific examples of the oligomer of ethylene glycol include diethylene glycol, triethylene glycol, tetraethylene glycol and the like, including those having a molecular weight distribution such as polyethylene glycol. In particular, diethylene glycol and triethylene glycol are preferable, and each may be used alone or in combination.

  The alcohol component (b-2) is preferably diethylene glycol and / or triethylene glycol, but other alcohols that can be used in combination include ethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, and tripropylene glycol. 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, cyclohexanediol, cyclohexanedimethanol, 2-methyl -1,3-propanediol, 3-methyl-1,5-pentanediol, glycerin, trimethylolpropane, pentaerythritol, erythritol, sorbitol, and other aliphatic and alicyclic alcohols, For synthesizing ordinary polyester polyols such as long-chain polyether polyols such as diols, aromatic alcohols such as 2-phenoxyethanol, polyethylene glycol, polypropylene glycol, polyoxyethylene / oxypropylene copolymer glycol, and polytetramethylene ether glycol The alcohol used can be used in combination. In order to obtain the desired biodegradability, mechanical strength, and solvent resistance, the ratio of the amount of other alcohol used excluding diethylene glycol and / or triethylene glycol should be 30 mol% or less of the total alcohol used. Is desirable.

  The hydroxyl value of the polyester polyol (b-3) in the present invention is in the range of 30 to 300 mgKOH / g, preferably in the range of 35 to 250 mgKOH / g, and more preferably in the range of 40 to 200 mgKOH / g. When the hydroxyl value is less than 30 mgKOH / g, the viscosity may increase and handling may be difficult. On the other hand, when the hydroxyl value is greater than 300 mgKOH / g, the molecular weight distribution of unreacted alcohol is increased, and the polyurethane elastomer is brittle and other physical properties. May be reduced.

  The polyester polyol (b-3) in the present invention is preferably liquid at 25 ° C. The viscosity at 25 ° C. measured with a B-type viscometer is easy to handle if it is 200 mPa · s or more and 30000 mPa · s or less, preferably 500 mPa · s or more and 27000 mPa · s or less, more preferably 1000 mPa · s or more and 25000 mPa · s. -S or less. When it is lower than 200 mPa · s, there is no problem in handling, but when it is higher than 30000 mPa · s, it may be difficult to handle.

  The average number of functional groups of the polyester polyol (b-3) in the present invention is usually in the range of 1.5 to 3.0. Preferably it is the range of 1.8-2.5. When the average number of functional groups is less than 1.5, the mechanical strength of the resulting polyurethane elastomer may be lowered. On the other hand, when it is larger than 3.0, the viscosity of the polyester polyol (b-3) is increased, which may make it difficult to handle. The most preferred average number of functional groups is 2.0.

  In the synthesis of the polyester polyol (b-3) in the present invention, an esterification catalyst is usually used. In general, an acid catalyst is often used as the esterification catalyst. Examples of the Lewis acid include orthotitanate esters such as tetraisopropyl titanate and tetra-n-butyl titanate, tin compounds such as diethyl tin oxide and dibutyl tin oxide, and metal compounds such as zinc oxide. In addition to the Lewis acid, a Bronsted acid such as p-toluenesulfonic acid can also be used.

  It is desirable that the catalyst used for the synthesis of the polyester polyol (b-3) does not affect the reaction behavior of the urethanization reaction. Therefore, among the above esterification catalysts, orthotitanate is preferable, and the amount used is usually 0.1% by weight or less, preferably 0, based on the total of the carboxylic acid component and the alcohol component used as a raw material. 0.05% by weight or less, usually 0.001% by weight or more, preferably 0.003% by weight or more. In some cases, the reaction may be carried out without using these esterification catalysts, and a deactivation treatment may be performed after the reaction, or it may be removed by purification or the like.

  The reaction temperature of the esterification reaction is usually 150 to 250 ° C, preferably 180 to 230 ° C. For example, the reaction is easy to control if the reaction is started at 150 ° C. and the temperature is gradually raised to 230 ° C. as the reaction proceeds. On the other hand, the reaction pressure can be normal pressure, but in order to remove by-product water out of the system and complete the reaction quickly, the pressure may be gradually reduced as the reaction proceeds. Here, when the degree of pressure reduction during the reaction is insufficient, the degree of completion of the esterification reaction is lowered, and a polyester polyol having a high acid value is produced. On the other hand, when the pressure is excessively reduced during the reaction, not only the alcohol component is distilled out of the system and the yield is deteriorated, but also a high molecular weight polyester polyol is formed, and the viscosity of the obtained polyester polyol may be remarkably increased. Therefore, the optimum ultimate reaction pressure varies depending on the reaction temperature. For example, when the reaction temperature is 200 ° C., the pressure is usually 1 kPa or more, preferably 3 kPa or more, and usually 50 kPa or less, preferably 30 kPa. Although it is the following, depending on the viscosity and hydroxyl value of the target polyester polyol, the type of alcohol used, and the amount used, it is also possible to carry out the reaction under conditions other than the above reaction pressure range. Further, instead of reducing the pressure, it is also possible to use a method in which a small amount of an organic solvent such as toluene or xylene is used in combination to azeotropically remove the by-produced water outside the system.

  The end point of the reaction of the polyester polyol (b-3) is usually determined by the amount of unreacted carboxyl groups of the used carboxylic acid component (b-1). On the other hand, in the use of the polyurethane elastomer, the presence of an acid, that is, the unreacted carboxyl group of the polyester polyol (b-3) is reacted with the urethanization reaction between the polyisocyanate component (a) and the polyester polyol (b-3). If the amount is large, the reactivity of the urethanization reaction is lowered, which is not preferable, and may deteriorate the stability over time of the polyurethane elastomer. Therefore, the amount of unreacted carboxylic acid of the polyester polyol (b-3), that is, the acid value is preferably as low as possible. In the use of the polyurethane elastomer, the acid value is usually 5 mgKOH / g or less, preferably 3 mgKOH / g or less, more preferably 1 mgKOH / g or less. Further, under more severe urethanization reaction conditions, 0.5 mgKOH / g or less may be desired.

  In order to keep the average number of functional groups of the polyester polyol (b-3) at a constant target value and / or to keep the hydroxyl value at a constant target value, the polyester polyol (b-3) is in an equilibrium state with the transesterification reaction during the esterification reaction. It is important not to distill alcohol out of the reaction system as much as possible. If the alcohol is distilled too much, the average number of functional groups of the ester compound will be different from the original product design, or the hydroxyl value will be reduced. As a result, the viscosity of the resulting polyester polyol (b-3) Is undesirably high. Therefore, the amount of alcohol distilled out of the system during the esterification reaction is usually controlled to be 5 mol% or less, preferably 3 mol% or less, more preferably 1 mol% or less with respect to the total alcohol. It is preferable to do. However, depending on the target viscosity and hydroxyl value of the polyester polyol and the amount of alcohol used, the alcohol may be distilled out beyond the above range.

  At the start of the reaction, it is preferable to replace the space of the reaction vessel with nitrogen in order to prevent coloring of the produced polyester polyol (b-3), and to further remove dissolved oxygen in the reaction solution. Moreover, after completion | finish of reaction, you may adjust the physical property and performance of polyester polyol (b-3) by distilling an unreacted alcohol component out of the system on suitable pressure-reduced conditions.

  The reaction mode of the polyester polyol (b-3) in the present invention can be applied in ordinary batch equipment or continuous equipment, but the reaction time is long and the viscosity of the resulting polyester polyol (b-3) is a raw material. Batch reaction is preferred because it is considerably higher than the alcohol used in

  Examples of a general method for producing the polyurethane elastomer in the present invention include a one-shot method and a prepolymer method. The one-shot method is a method of obtaining a polyurethane elastomer by simultaneously reacting a polyisocyanate component (a), a polyol component (b), a crosslinking agent (d) and other auxiliary agents as required, and a prepolymer method is a polyisocyanate component. (A), the polyol component (b) and, if necessary, other auxiliary agents are reacted to produce an isocyanate prepolymer (c), and then the crosslinking agent (d) and other auxiliary agents are further reacted as required. This is a method for obtaining a high molecular weight polyurethane elastomer. For the purpose of producing a polyurethane elastomer having stable physical properties, the prepolymer method is preferred.

  The isocyanate prepolymer (c) in the present invention is an isocyanate prepolymer (c) obtained by reacting at least the polyisocyanate component (a) and the polyol component (b), and is at least a part of the polyol component (b). Uses a polyester polyol (b-3) obtained by reacting a carboxylic acid component (b-1) with an alcohol component (b-2). The prepolymer has an isocyanate group derived from the polyisocyanate component (a) as a terminal group, and the concentration of the terminal isocyanate group can be quantified by titration as “% NCO”.

  The polyisocyanate component (a) is not particularly limited as long as it is an organic compound having two or more isocyanate groups in one molecule. For example, aliphatic such as hexamethylene diisocyanate, alicyclic such as isophorone diisocyanate and xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated tolylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, phenylene diisocyanate, polyphenylene polymethylene polyisocyanate, etc. Aromatic polyisocyanates or modified products thereof can be mentioned. Furthermore, these carbodiimide modified products and urethane modified products are also included. Preferred polyisocyanates are diphenylmethane diisocyanate and hexamethylene diisocyanate.

  As the polyol component (b), at least the polyester polyol (b-3) is used. Other than these, ether polyols such as polypropylene glycol (PPG) and polytetramethylene ether glycol (PTMG), ester polyols such as adipic acid esters, lactone polyols such as polycaprolactone, carbonates Based polyols and the like. Those having a number average molecular weight of about 500 to 5,000 can be suitably used. When used in combination with the polyester polyol (b-3) of the present invention, the amount used is desirably 50% by weight or less of the ratio of the total polyol. Most preferably, the polyester polyol (b-3) is used as the total amount of the polyol component (b).

  In the prepolymer method, a polyisocyanate (a) and a polyol component (b) are reacted to obtain an isocyanate prepolymer (c), and then a crosslinking agent (d) and other auxiliary agents are reacted as necessary to produce a polyurethane elastomer. Is the way to get.

As the prepolymer method, for example, the following procedure is performed.
(1) Polyisocyanate component (a) and polyol component (b) are added 1.1 to 5 times (NCO group / OH group ratio) of polyisocyanate component (a) to 1 mol of polyol component (b). To react to synthesize an isocyanate prepolymer (c). The reaction temperature at this time is about 60 to 120 ° C., and the reaction time is about 1 to 8 hours.
(2) The isocyanate prepolymer (c) and the crosslinking agent (d) are mixed, stirred and degassed under reduced pressure. At this time, the stirring time is 20 to 60 seconds, and the temperature is about 60 to 120 ° C.
(3) A mixed liquid of the isocyanate prepolymer (c) and the cross-linking agent (d) is poured into a mold that has been heated in advance, and is cured by heating. The temperature at this time is about 60 to 200 ° C., and the time is about 2 to 48 hours.
(4) The polyurethane elastomer is removed from the mold, and if necessary, the polyurethane elastomer is heated or cured at a normal temperature.

  As the crosslinking agent (d), two or more active hydrogens in one molecule such as alcohols such as ethylene glycol, diethylene glycol, 1,4-butanediol, propylene glycol and glycerin, alkanolamines such as diethanolamine and triethanolamine, etc. The compound which has is used. Preferred examples of the crosslinking agent include ethylene glycol and 1,4-butanediol. In addition, the usage-amount of a crosslinking agent (d) is suitably selected so that it may become a desired NCO / OH ratio.

  Use other auxiliaries as necessary. Other uses of auxiliary agents are mainly catalysts for promoting or slowing urethanization reaction, reactivity modifiers, plasticizers, fillers, antioxidants, defoamers for adjusting the properties of polyurethane elastomers. , Surfactants and the like. These additives and auxiliaries are not particularly limited, and are used for the purpose of improving physical properties and operability in ordinary polyurethane elastomers, and are used within the range where the effects of the present invention can be obtained. May be.

  In the present invention, the target polyurethane elastomer may be obtained by a one-shot method using the polyol (b-3). In this case, the above-mentioned polyisocyanate component (a), polyol component (b), cross-linking agent (d) and other auxiliary agents as necessary can be reacted simultaneously to obtain a polyurethane elastomer. In addition, the usage-amount of each component is suitably selected within the range according to the said prepolymer method.

  Hereinafter, specific embodiments of the present invention will be described in more detail by way of examples. However, the present invention is not limited by these examples unless it exceeds the gist. Unless otherwise specified, “parts” and “%” in the examples mean “parts by weight” and “% by weight”, respectively.

The polyol component (b) used in the present invention is as follows. Table 1 shows the composition, acid value, hydroxyl value, viscosity, and number average molecular weight of the carboxylic acid component (b-1) and the alcohol component (b-2), respectively.
“Polyol-1 to 7, 10” were synthesized according to the following “Reference Example”, and “Polyol-8, 9” was as follows.
Polyol-8: Polytetramethylene ether glycol “PTMG1000” manufactured by Mitsubishi Chemical Corporation
Polyol-9: Polytetramethylene ether glycol “PTMG2000” manufactured by Mitsubishi Chemical Corporation

Reference example
[Synthesis of polyester polyol]
The polyester polyol (b-3) was synthesized and evaluated by the method shown below.
<Synthesis method>
A glass reactor equipped with a stirrer, reflux condenser, thermometer, pressure gauge, oil bath, etc. and having a volume of 2 liters was charged with carboxylic acid and alcohol according to the composition ratio shown in Table 1, and the reactor After replacing the space with nitrogen gas, heating of the reactor was started. When the reactor internal temperature reached about 150 ° C., the esterification reaction started and by-product water began to distill. Thereafter, the internal temperature was raised to 210 ° C. over about 2 hours while observing the amount of by-product water distilled off, and 0.01% of tetraisopropyl titanate (total charge) as a catalyst was added to the reactor. Thereafter, this temperature was maintained at 210 ° C. until the reaction was completed. The pressure in the reactor was maintained at about 88 kPa until the internal temperature reached 150 ° C. from 210 ° C. Thereafter, the pressure was gradually reduced from 13 to 3.0 kPa over about 4 hours, and this pressure was maintained until the reaction was completed. It was visually observed that the reaction mixture became a homogeneous solution as the reaction proceeded. During the progress of the reaction, a part of the reaction mixture was extracted from the reactor, and the acid value of the extracted sample was measured as an index for confirming the progress of the reaction. The reaction was terminated when the acid value reached about 0.5 and the reaction mixture became a homogeneous solution. After completion of the reaction, the heating was stopped and the mixture was cooled to about 100 ° C., and the reaction product was extracted. The polyester polyols obtained here are shown in Table 1 as “polyols 1 to 7, 10”.

<Evaluation method>
(1) Acid value It measured based on JISK1557 ₁₉₇₀ .
(2) Hydroxyl value Measured according to JIS K1557 ₁₉₇₀ .
(3) Viscosity Using a rotational viscometer (B-type viscometer) in accordance with JIS K1557 ₁₉₇₀ , the viscosity was measured at 25 ° C.

[Synthesis of isocyanate prepolymer]
Isocyanate prepolymers “Prepolymer-1 to 9” were synthesized with the raw materials and blends shown in Table 2. Moreover,% NCO (terminal isocyanate group concentration) of the isocyanate prepolymer was measured and shown in Table 2 (Examples 1 to 3 and Comparative Examples 1 to 6). The following materials were used.
Polyol-1 to 9: Polyol described above Polyisocyanate: Diphenylmethane diisocyanate “Millionate MT” manufactured by Nippon Polyurethane Industry Co., Ltd.
Reactivity modifier: Phosphate ester “JP-504” manufactured by Johoku Chemical Co., Ltd.
<Synthesis method>
A glass reactor equipped with a stirrer, thermometer, pressure gauge, oil bath, etc. and having a volume of 1 liter is charged with polyol, polyisocyanate, and reactivity modifier according to the mixing ratio shown in Table 2, Was degassed under reduced pressure. Thereafter, the space of the reactor was replaced with nitrogen gas, and then the reactor was started to be heated at normal pressure. The reaction was started when the internal temperature reached 80 ° C., and the reaction was performed for 2 hours while depressurizing the system and degassing every 30 minutes. The isocyanate prepolymer obtained here is shown in Table 2 as "Prepolymer-1 to 9".

<Evaluation method>
% NCO (concentration of terminal isocyanate group)
The measurement was performed according to JIS K1556 ₁₉₆₈ using dimethylformamide as a solvent.

The polyurethane elastomer sheet was molded and evaluated by the following method (Examples 4 to 7 and Comparative Examples 7 to 15). The following materials were used.
Prepolymers 1 to 9: The above-mentioned prepolymers Crosslinking agent: 1,4-butanediol Special grade reagent Wako Pure Chemical Industries, Ltd. [Polyurethane elastomer sheet molding]
<Molding method>
Measure the prepolymer preheated to 80 ° C into a SUS reactor, add a predetermined amount of cross-linking agent with a syringe, and immediately set it in a vacuum stirrer. Stir for 30 seconds while degassing under reduced pressure It was. Then, it was poured into a molding die of a 2 mm thick sheet preheated to 80 ° C., and was heated and cured for one day in a 120 ° C. oven. Thereafter, the polyurethane elastomer sheet was demolded and stored in the room for 2 days or more, and used for evaluation. The blending ratio of the prepolymer and the crosslinking agent was 1.05 in terms of isocyanate index (NCO group / OH group molar ratio).
<Mold>
Aluminum inner dimensions 200mm x 200mm x 2mm The following mold release agent is used Fluorine-based mold release spray: "Daifree GA-6010" manufactured by Daikin Industries, Ltd.

The obtained polyurethane elastomer was evaluated by the following method, and the results are shown in Tables 3 and 4.
<Evaluation method>
(1) Mechanical strength The mechanical strength measured in accordance with JIS A7311 ₁₉₉₅ is shown in Table 3, Table 4, and Table 5. The following tensile and tear specimens were used.
Tensile test piece: JIS K7113 No. 2 Tear test piece: JIS K7311 No. 3 Note that tensile test results (breaking strength, breaking elongation, 100% modulus, 200% modulus, 300% modulus and elastic modulus) and tearing test results (tear strength) ) Is shown in Tables 4 and 5 as intensity averages.
(2) Biodegradability After immersing a test piece for measuring mechanical strength in water (60 ° C) for 1 week, measuring the mechanical strength, evaluating how much the original mechanical strength was lost by hydrolysis, It was used as a standard for degradability. The result was shown by the value (%) after immersion with respect to the value before immersion.
(3) Solvent resistance After immersing a test piece for measuring mechanical strength in toluene, ethyl acetate or isopropyl alcohol for 1 week, the weight change and mechanical strength were measured. The degree of loss was evaluated and used as a measure of solvent resistance. The results were each expressed as a value (%) after immersion with respect to the value before immersion.

From Tables 1 to 5, the following is apparent.
(1) Comparison results of polyols 1 to 3, polyols 4, 5 and polyols 8, 9, and 10 From Table 1, polyol 4 synthesized using succinic acid or adipic acid and 1,4-butanediol, Polytetramethylene ether glycols such as 5, 10 and polyols-8 and 9 are solid at 25 ° C., whereas succinic acid is used as the carboxylic acid of the present invention, and diethylene glycol and / or triethylene glycol is used as the alcohol. Polyols 1 to 3 synthesized in this way remain liquid even at 25 ° C.

(2) Comparative results of Examples 4 to 6 and Comparative Examples 7 to 12 From Table 3, mechanical strength evaluation of polyurethane elastomers (breaking strength, breaking elongation, 100% modulus, 200% modulus, 300% modulus, elastic modulus and In the case of Examples 4 to 6 using succinic acid as the carboxylic acid of the present invention and polyols 1 to 3 synthesized using diethylene glycol and / or triethylene glycol as the alcohol in tear strength) Compared with Comparative Examples 7 to 12 using polyols 4 to 9, the properties are not inferior.

(3) Comparative results of Examples 7 and 8 and Comparative Examples 13 to 15 From Table 4, in the biodegradability evaluation of the polyurethane elastomer, succinic acid was used as the carboxylic acid of the present invention, and diethylene glycol and / or triethylene glycol as the alcohol. In the case of Examples 7 and 8 using polyols 1 and 2 synthesized using the above, the average strength after soaking in water (60 ° C.) is reduced to about 40 to 70% before soaking. In Comparative Examples 13 to 15 using polyols 4, 6, and 8, which are used in general, the strength average is 80 to 90%. This shows that when the polyol of the present invention is used, the hydrolyzability (biodegradability) of the polyurethane elastomer is improved.

(4) Comparative results of Examples 7 to 9 and Comparative Examples 13 to 18 From Tables 4 and 5, in the solvent resistance evaluation of the polyurethane elastomer, succinic acid was used as the carboxylic acid of the present invention, and diethylene glycol and / or trimethyl was used as the alcohol. In the case of Examples 7 to 9 using polyols 1 and 2 synthesized using ethylene glycol, the average strength after immersion in the solvent was compared with Comparative Examples 13 to 18 using polyols 4, 6, and 8 that were used for general purposes. On the other hand, the increase in weight due to swelling is small. This shows that the solvent resistance of the polyurethane elastomer is improved.

  According to the present invention, in an isocyanate prepolymer and a polyurethane elastomer, physical properties such as mechanical strength and solvent resistance can be maintained, and high biodegradability can be imparted.

Claims (7)

  Is an isocyanate prepolymer (c) obtained by reacting at least a polyisocyanate component (a) and a polyol component (b), and at least a part of the polyol component (b), In the isocyanate prepolymer (c) using the polyester polyol (b-3) obtained by reacting the alcohol component (b-2), succinic acid is used as the carboxylic acid component (b-1), and the alcohol component (b-2). ), An isocyanate prepolymer (c), characterized in that ethylene glycol and / or an oligomer thereof is used.   Is an isocyanate prepolymer (c) obtained by reacting at least a polyisocyanate component (a) and a polyol component (b), and at least a part of the polyol component (b), In the isocyanate prepolymer (c) using the polyester polyol (b-3) obtained by reacting the alcohol component (b-2), succinic acid is used as the carboxylic acid component (b-1), and the alcohol component (b-2). Diethylene glycol and / or triethylene glycol is used as the isocyanate prepolymer (c).   Is an isocyanate prepolymer (c) obtained by reacting at least the polyisocyanate component (a) and the polyol component (b), and the carboxylic acid component (b-1) and the alcohol component as the total amount of the polyol component (b). In the isocyanate prepolymer (c) using the polyester polyol (b-3) obtained by reacting (b-2), succinic acid is used as the carboxylic acid component (b-1), and as the alcohol component (b-2). Isocyanate prepolymer (c) using diethylene glycol and / or triethylene glycol.   A polyurethane elastomer obtained by reacting at least the crosslinking agent (d) and the isocyanate prepolymer (c) according to any one of claims 1 to 3.   A polyurethane elastomer obtained by reacting at least a polyisocyanate component (a) with a polyol component (b) and a crosslinking agent (d), wherein at least part of the polyol component (b) is a carboxylic acid component (b-1). ) And an alcohol component (b-2), the polyurethane elastomer using the polyester polyol (b-3) obtained by using succinic acid as the carboxylic acid component (b-1) and as the alcohol component (b-2) A polyurethane elastomer using ethylene glycol and / or an oligomer thereof.   A polyurethane elastomer obtained by reacting at least a polyisocyanate component (a) with a polyol component (b) and a crosslinking agent (d), wherein at least part of the polyol component (b) is a carboxylic acid component (b-1). ) And an alcohol component (b-2), the polyurethane elastomer using the polyester polyol (b-3) obtained by using succinic acid as the carboxylic acid component (b-1) and as the alcohol component (b-2) A polyurethane elastomer using diethylene glycol and / or triethylene glycol.   A polyurethane elastomer obtained by reacting at least a polyisocyanate component (a), a polyol component (b), and a crosslinking agent (d), wherein the total amount of the polyol component (b) is the carboxylic acid component (b-1) In the polyurethane elastomer using the polyester polyol (b-3) obtained by reacting the alcohol component (b-2), succinic acid is used as the carboxylic acid component (b-1), and diethylene glycol and the alcohol component (b-2) are used. A polyurethane elastomer characterized by using triethylene glycol.