JP2010234530A - Urethane elastomer composition for printing roll, and printing roll - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a urethane elastomer composition for a printing roll which is excellent both in solvent resistance and water resistance, and a printing roll formed of the composition. <P>SOLUTION: The urethane elastomer composition for a printing roll is obtained by using polyisocyanate (A), polyester polyol (B). The urethane elastomer composition is characterized in that the polyester polyol (B) contains inevitably 1,3-propanediol as a hydroxy ingredient, and a succinic acid as a carboxyl group ingredient. The printing roll is obtained by molding the urethane elastomer composition for a printing roll. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a urethane elastomer composition for printing rolls, and a printing roll using the composition. More specifically, the present invention relates to a composition for forming a urethane elastomer suitable for an elastic member of a printing roll, and a printing roll formed by using the urethane elastomer composition.

  Conventionally, a printing roll has been required to have high solvent resistance because the printing ink used is a solvent-based ink. However, in recent years, there have been concerns about adverse effects on the environment and living organisms, and there has been a gradual shift from solvent-based ink to water-based ink, and the amount of water-based ink used has increased.

  Therefore, in addition to the solvent resistance that has been required for solvent-based inks, water-based inks are also required to have excellent water resistance as an essential performance.

  In addition, since water-based inks contain a small amount of an organic solvent or a cleaning solvent is used, excellent solvent resistance is required as in the case of conventional solvent-based inks.

  Up to now, the polyester for polyurethane elastomer is heated, the plasticizer is injected and stirred, the curing agent is injected and stirred, dehydrated under reduced pressure, injected into the mold, and heated and released after sulfiding. A method of manufacturing a polyurethane roller, which is a polyurethane roller for a printing press, in which a plasticizer is diethyl phthalate and a curing agent includes tolylene diisocyanate is known (for example, see Patent Document 1). ).

  The manufacturing method described in Patent Document 1 can provide a polyurethane roller that has a lower hardness than conventional urethane rollers to improve printing performance and is not easily affected by the solvent of the ink.

  However, the polyurethane roller for a printing press obtained by the production method described in Patent Document 1 has a high ester group-containing concentration of the polyester polyol used as a raw material because it places importance on solvent resistance. Inferior in nature and problematic in practical use.

  Moreover, it is a composition for forming the urethane elastomer of JIS-A hardness 20-90 which comprises the elastic member of a printing roll, Comprising: Polyisocyanate and the polyol which uses a polycarbonate-type polyol as an essential component are contained. A printing roll comprising a urethane elastomer-forming composition and an elastic member formed by curing the urethane elastomer-forming composition in a mold is known (for example, see Patent Document 2). .

  The composition described in Patent Document 2 has good water resistance, solvent resistance, and alkali resistance, and can form a urethane elastomer suitable as an elastic member of a printing roll in contact with aqueous ink. Since the printing roll includes an elastic member having good water resistance, solvent resistance and alkali resistance, it is possible to print a beautiful image with water-based ink over a long period of time.

  However, the urethane elastomer-forming composition using the polycarbonate polyol described in Patent Document 2 has good water resistance (that is, hydrolysis resistance), but is used for a solvent contained in water-based ink or for washing. There is a problem that the solvent resistance is still inferior to the solvent.

  As described above, the conventional technology is still insufficient in terms of performance, and the development of a urethane elastomer composition for printing rolls that is excellent in both solvent resistance and water resistance, and printing rolls using the same is desired. It was.

JP-A-5-301335

JP 2004-217844 A

  The problem to be solved by the present invention is to provide a urethane elastomer composition for printing rolls having both excellent solvent resistance and water resistance, and a printing roll using the same.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor, in a urethane elastomer composition obtained using a polyisocyanate and a polyester polyol, the polyester polyol is a 1,3-3-functional component containing a hydroxyl group. It has been found that a urethane elastomer composition for printing rolls and printing rolls having both excellent solvent resistance and water resistance can be obtained by making propanediol essential and succinic acid essential as a carboxyl group-containing component. The present invention has been completed.

  That is, the present invention is a urethane elastomer composition obtained by using a polyisocyanate (A) and a polyester polyol (B), wherein the polyester polyol (B) is 1,3-propane as a hydroxyl group-containing difunctional component. The present invention relates to a urethane elastomer composition for printing rolls characterized in that a diol is essential and succinic acid is essential as a carboxyl group-containing component.

  Moreover, this invention relates to the printing roll characterized by shape | molding the said urethane elastomer composition for printing rolls.

  The urethane elastomer composition for printing rolls of the present invention has both excellent solvent resistance and water resistance. Moreover, since the printing roll formed by molding the urethane elastomer composition for printing rolls of the present invention has both excellent solvent resistance and water resistance, not only conventional solvent-based inks but also water-based inks are used. For example, printing rolls used for various types of printing such as gravure printing, flexographic printing, and offset printing can be used.

  The urethane elastomer composition for printing rolls of the present invention is a urethane elastomer composition obtained using a polyisocyanate (A) and a polyester polyol (B), and the polyester polyol (B) is a hydroxyl group-containing difunctional component. 1,3-propanediol is essential, and succinic acid is essential as a carboxyl group-containing component.

  It does not specifically limit as said polyisocyanate (A), A conventionally well-known thing can be used. Specifically, diphenylmethane diisocyanate (abbreviation MDI; 4,4′-form, 2,4′-form, 2,2′-form, or a mixture thereof), polymethylene polyphenyl polyisocyanate, carbodiimidized diphenylmethane Polyisocyanate, tolylene diisocyanate (TDI; 2,4, 2,6, or a mixture thereof), xylylene diisocyanate (XDI), 1,5-naphthalene diisocyanate (NDI), tetramethylxylene Aromatic diisocyanates such as diisocyanates, or alicyclic diisocyanates such as isophorone diisocyanate (IPDI), hydrogenated diphenylmethane diisocyanate (hydrogenated MDI), hydrogenated xylylene diisocyanate (hydrogenated XDI), hexamethylene diisocyanate ( DI), dimer acid diisocyanate, aliphatic diisocyanates such as norbornene diisocyanate and the like, may be used in combination of two or more kinds of these alone. Among these, polymethylene polyphenyl polyisocyanate is preferable for reasons such as moderate reactivity, excellent mechanical strength, and solvent resistance.

  The polyester polyol (B) used in the urethane elastomer composition for printing rolls of the present invention comprises 1,3-propanediol as an essential component as a hydroxyl group-containing difunctional component.

  In the present invention, all of the hydroxyl group-containing difunctional component may be 1,3-propanediol, but together with 1,3-propanediol as a part of the hydroxyl group-containing bifunctional component, other than 1,3-propanediol A hydroxyl group-containing difunctional component may be used.

  The hydroxyl group-containing bifunctional component other than the 1,3-propanediol is not particularly limited, and examples thereof include ethylene glycol, 1,2-propanediol, 2,2-dimethyl-1,3-propanediol, 1, 3-butanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 3,3′-dimethylol heptane, 1,4- Examples include cyclohexanedimethanol, 3,3-bis (hydroxymethyl) heptane, diethylene glycol, dipropylene glycol, and triethylene glycol. Among these, ethylene glycol, 1,4 in terms of solvent resistance and handling properties. -Butanediol and diethylene glycol are preferred, and ethylene glycol is more preferred . These may be used alone or in combination of two or more.

  Further, ring-opening polymerization type polyester polyols can be used. For example, polycaprolactone polyols, polybutyrolactone polyols and the like obtained by ring-opening polymerization of cyclic ester compounds (ie, lactones) such as ε-caprolactone and γ-butyrolactone. Examples thereof include ring-opening polymerization type polyester polyols.

  A hydroxyl group-containing polyfunctional component may be used for the polyester polyol (B) as long as the object of the present invention is not impaired. The hydroxyl group-containing polyfunctional component refers to a trifunctional or higher functional polyol having a hydroxyl group in the molecule.

  Examples of the hydroxyl group-containing polyfunctional component include trifunctional components such as trimethylolpropane, glycerin, pentaerythritol, and hexanetriol, or difunctional compounds such as trimethylolpropane and pentaerythritol, and trifunctional components such as saccharides such as sorbitol. Among these, trimethylolpropane and glycerin are preferred, and trimethylolpropane is more preferred from the viewpoint of handleability. These may be used alone or in combination of two or more.

  By using an appropriate amount of such a hydroxyl group-containing polyfunctional component, the solvent resistance can be improved, specifically, the urethane elastomer can be prevented from swelling due to the solvent.

  The composition ratio of the hydroxyl group-containing difunctional component is ethylene glycol (EG) / 1,3-propanediol (1,3PG) = 10/90 to 90/10 molar ratio, and the hydroxyl group-containing difunctional component / hydroxyl group. Containing polyfunctional component = 90/10 to 99/1 molar ratio is preferable, EG / 1,3PG = 30/70 to 70/30 molar ratio, and hydroxyl group-containing difunctional component / hydroxyl group-containing polyfunctional The component = 93/7 to 97/3 molar ratio is more preferable.

  In the composition ratio of the hydroxyl group-containing difunctional component, when the EG / 1,3PG molar ratio is smaller than the 10/90 molar ratio, the EG is insufficient with respect to 1,3PG, so that the durability against low polar solvents is poor. It is not preferable. Moreover, when EG / 1,3PG molar ratio is larger than 90/10 molar ratio, since EG is excessive, the viscosity of a polyester polyol becomes high too much, and handling property is inferior, and is not preferable.

  In addition, when the hydroxyl group-containing difunctional component / hydroxyl group-containing polyfunctional component molar ratio is larger than 99/1 molar ratio, the hydroxyl group-containing polyfunctional component is insufficient with respect to the hydroxyl group-containing difunctional component, so the crosslinking density is low. Thus, the solvent resistance is lowered, which is not preferable. Further, when the hydroxyl group-containing difunctional component / hydroxyl group-containing polyfunctional component molar ratio is smaller than 90/10 molar ratio, the hydroxyl group-containing polyfunctional component is excessive with respect to the hydroxyl group-containing difunctional component, so that the crosslinking density is high. Therefore, the viscosity of the polyester polyol becomes too high, the handling property is inferior, and there is a risk of gelation.

  Moreover, the polyester polyol (B) used by this invention has a succinic acid as an essential component as a carboxyl group-containing component.

  In the present invention, all of the carboxyl group-containing components may be succinic acid, but a carboxyl group-containing component other than succinic acid may be used together with succinic acid as part of the carboxyl group-containing component.

  The carboxyl group-containing component other than the succinic acid is not particularly limited, but examples thereof include aliphatic polybasic acids such as adipic acid, azelaic acid, sebacic acid, and dodecanedicarboxylic acid, cyclopentanedicarboxylic acid, cyclohexanedicarboxylic acid, and the like. Examples thereof include aromatic polybasic acids such as alicyclic polybasic acid, orthophthalic acid, isophthalic acid, terephthalic acid and naphthalenedicarboxylic acid. These may be used alone or in combination of two or more.

  The urethane elastomer composition for printing rolls of the present invention comprises the polyester polyol (B) as an essential component. For example, polyols other than polyester polyols such as polyether polyols and polycarbonate polyols may be used in a range that does not impair the object of the present invention. Can be used.

  The number average molecular weight (hereinafter also referred to as “Mn”) of the polyester polyol (B) is preferably in the range of 1000 to 3000, and more preferably in the range of 1500 to 2500. When the Mn of the polyester polyol (B) is less than 1000, there is a tendency for elasticity to be insufficient, which is preferable. Moreover, when Mn of said (B) exceeds 3000, there exists a tendency for handling property to fall and it is unpreferable.

  In the urethane elastomer composition for printing rolls of the present invention, when the number of moles of isocyanate group of the polyisocyanate (A) is represented as [NCO] and the number of moles of hydroxyl group of the polyester polyol (B) is represented as [OH]. The equivalent ratio ([NCO] / [OH]) of the polyisocyanate (A) and the polyester polyol (B) is preferably in the range of 0.90 to 1.10, more preferably 1.00 to 1. .05 range. When the equivalent ratio ([NCO] / [OH]) of (A) and (B) is within such a range, surface hardness and elasticity suitable for a printing roll can be obtained.

  The urethane elastomer composition for printing rolls of the present invention contains, as an optional component, various known additives used in ordinary elastomer compositions (polyurethane raw materials) as long as the object of the present invention is not impaired. Can do.

  Examples of such optional components include, but are not limited to, catalysts, plasticizers, antioxidants, defoaming agents, antifoaming agents, ultraviolet absorbers, reaction modifiers, reinforcing agents, fillers, colorants (dyes or pigments). ), Release agents, stabilizers, light stabilizers, electrical insulation improvers, fungicides, organic acid metal salts, waxes (amides, etc.), metal oxides, metal hydroxides and other extenders Can be mentioned.

The method for adjusting the urethane elastomer composition for printing rolls of the present invention is not particularly limited, but if an example is given, a polyol containing polyisocyanate (A) and polyester polyol (B) as essential components, various additives, and the like. Can be prepared by stirring and mixing, and if necessary, vacuum defoaming treatment.

  The printing roll of the present invention is a urethane elastomer molded product formed by curing the urethane elastomer composition for a printing roll of the present invention in a mold.

  Examples of the “printing roll” in the present invention include various rolls (ink calling, ink kneading, ink application, etc.) that can be used for various printing such as gravure printing, flexographic printing, and offset printing.

Although the urethane elastomer which comprises the printing roll of this invention can be shape | molded by a conventionally well-known shaping | molding method, it shape | molds by the process (1)-(3) shown below, for example.

Step (1): Polyisocyanate (A), polyester polyol (B), other optional additives, etc. are mixed by stirring manually or with a mixer, and then vacuum degassed to produce the urethane elastomer composition of the present invention. obtain.
Step (2): The urethane elastomer composition is poured into a preheated mold and cured under specific temperature conditions to react the polyisocyanate (A) with the polyester polyol (B).
Step (3): The molded product after the curing treatment can be taken out from the mold and the desired printing roll can be obtained.

  The mixing method is not particularly limited, such as manual mixing and mechanical mixing, and various known methods can be employed.

  Curing conditions (temperature, time, etc.) for the curing treatment are not particularly limited, but are preferably 1 to 24 hours at 60 to 150 ° C, and more preferably 2 to 16 hours at 80 to 120 ° C.

  The mold used is preferably preheated, and the preheating temperature is not particularly limited, but is preferably 60 to 150 ° C.

  In addition, when this urethane elastomer is an elastomer layer which coat | covers a metal core, the target printing roll is obtained by operation similar to the above-mentioned shaping | molding method except incorporating the said metal core into a shaping | molding die. The effect of the present invention is not impaired even when a printed roll is configured by mounting a molded urethane elastomer on a cored bar.

  Since the urethane elastomer constituting the printing roll of the present invention has a balanced performance with excellent solvent resistance and water resistance, it can be used for both solvent-based inks and water-based inks. Very little change and excellent stability.

  Therefore, according to the printing roll of the present invention, it is possible to stably print a beautiful image over a long period of time using either a solvent-based ink or a water-based ink.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the scope of the present invention is not limited only to these examples. The measurement method and evaluation method used in the present invention are as follows.

[Measuring method of melt viscosity of polyester polyol (B)]
The melt viscosity (mPa · s) of each polyester polyol (B) in a heated and melted state at 75 ° C. was measured under the following conditions.
Measuring instrument: Digital cone viscometer (MST Engineering Co., Ltd.)
Cone diameter: 24.0 mm
Angle: 0.5 °

[Measuring method of melting point of polyester polyol (B)]
About 10 mg of each polyester polyol (B) is weighed in a measurement container, and nitrogen gas is measured using a differential scanning calorimeter (model: DSC 220C, manufactured by Seiko Electronics Co., Ltd.) (hereinafter abbreviated as “DSC”). The temperature was raised from 20 ° C. to 210 ° C. at a flow rate of 50 ml / min and a heating rate of 10 ° C./min, then held at 210 ° C. for 3 minutes, then cooled to −100 ° C. at a cooling rate of 50 ° C./min, By performing the secondary temperature increase to 200 ° C., the melting point (° C.) was determined from the DSC curve drawn on the chart.

[Molding method]
Hyprox 1225 (trademark, manufactured by DIC Corporation, Crude MDI), which is a polyisocyanate (A), and each polyester polyol (B) are blended at a blending ratio of [NCO] / [OH] = 1.00 equivalent ratio and stirred and mixed. And poured into a sheet-shaped mold having a thickness of 2 mm and a cylindrical mold having a diameter of 4.0 cm and a thickness of 1.2 cm, and primarily cured with a 120 ° C. dryer for 2 hours, and further with a 110 ° C. dryer for 16 hours, Secondary curing is performed to form a molded product of the desired urethane elastomer.

[Measurement method of JIS-A hardness]
JIS-A hardness is measured according to the durometer hardness test prescribed | regulated to Japanese Industrial Standard JIS-K-6253, using the cylinder created as mentioned above as a test body.

[Water resistance test]
(1) Water resistance test method The sheet of 2 mm thickness prepared as described above is punched out to 5.0 cm × 2.5 cm, and the mass change rate after the test body is immersed in ion-exchanged water at 40 ° C. for 3 days is expressed by the following equation: taking measurement.
(2) Calculation method of mass change rate Mass change rate (%) = W ₁ / W ₀ × 100
In the formula, W ₀ and W ₁ mean the following.
W ₀ : Mass of sheet before immersion W ₁ : Mass of sheet after immersion for 3 days at 40 ° C. in ion-exchanged water (3) Evaluation of water resistance test results Evaluation of the water resistance test results was performed according to the following criteria.
Evaluation of water resistance test A: Less than 102.5% and excellent in water resistance.
○: 102.5% or more and less than 103.0%, and water resistance is good.
Δ: 103.0% or more and less than 103.5%, slightly inferior in water resistance.
X: 103.5% or more, extremely inferior in water resistance.

[Moisture and heat resistance test]
(1) Moisture and heat resistance test method The specimen used for the above hardness measurement is left in a constant temperature and humidity chamber set at 75 ° C. in an atmosphere with a relative humidity of 95%, and the hardness change rate is measured by measuring the hardness after 3 days. (%) Is calculated by the following formula and the heat and moisture resistance is evaluated.
(2) Calculation method of rate of change in hardness Rate of change in hardness (%) after 3 days = H ₁ / H ₀ × 100
In the formula, H ₀ and H ₁ mean the following.
H ₀ : JIS-A hardness of the cylinder before the test H ₁ : JIS-A hardness of the cylinder after curing for 3 days in an atmosphere at 75 ° C. and 95% (3) Evaluation of the moisture and heat resistance test results Evaluation of the moisture and heat resistance test results The following criteria were followed.
Evaluation of moisture and heat resistance test A: 90% or more, excellent in heat and moisture resistance.
○: 85% or more and less than 90%, and good heat and humidity resistance.
Δ: 80% or more and less than 85%, slightly inferior in heat and moisture resistance.
X: Less than 80% and extremely inferior in heat and humidity resistance.

[Solvent resistance test]
(1) Solvent resistance test method The specimens used for the above hardness measurement were immersed in toluene, methyl ethyl ketone (MEK) and butyl cellosolve at 25 ° C for 3 days, respectively, and the rate of change in hardness (%) was calculated according to the following formula. Evaluate solvent resistance.
(2) Calculation method of hardness change rate Hardness change rate after 3 days (%) = h ₁ / h ₀ × 100
In the formula, h ₀ and h ₁ mean the following.
h ₀ : JIS-A hardness of the cylinder before the test h ₁ : JIS-A hardness of the cylinder after being immersed in each solvent at 25 ° C for 3 days (3) Evaluation of the solvent resistance test result The evaluation of the solvent resistance test result is The following criteria were followed.
Evaluation of solvent resistance test A: 95% or more, excellent in solvent resistance.
A: 90% or more and less than 95%, solvent resistance is good.
Δ: 85% or more and less than 90%, slightly inferior in solvent resistance
X: Less than ~ 85% and extremely poor in solvent resistance.

[Synthesis of Polyester Polyols (B1) to (B9) (Synthesis Examples 1 to 9)]

[Synthesis Example 1]
In a 2-liter four-necked flask, 713 parts of 1,3-propanediol (hereinafter abbreviated as “1,3PD”), 65 parts of ethylene glycol (hereinafter abbreviated as “EG”), trimethylolpropane (hereinafter referred to as “TMP”). (Abbreviated) 58 parts, succinic acid (hereinafter abbreviated as “SucA”) 1175 parts, tetrabutyl titanate 0.06 parts were charged, and reacted at 220 ° C. for 24 hours under a nitrogen stream from a nitrogen introduction tube. After the reaction, the obtained polyester polyol (B1) was a white solid at room temperature, and had an acid value of 0.45 and a hydroxyl value of 59.6.

[Synthesis Example 2]
A 2-liter four-necked flask was charged with 565 parts of 1,3PD, 197 parts of EG, 58 parts of TMP, 1197 parts of SucA, 0.06 part of tetrabutyl titanate, and reacted at 220 ° C. for 24 hours under a nitrogen stream from a nitrogen introduction tube. It was. After the reaction, the obtained polyester polyol (B2) was a white solid at room temperature, and had an acid value of 0.37 and a hydroxyl value of 59.5.

[Synthesis Example 3]
A 2-liter four-necked flask was charged with 411 parts of 1,3PD, 335 parts of EG, 59 parts of TMP, 1219 parts of SucA, 0.06 part of tetrabutyl titanate, and allowed to react at 220 ° C. for 24 hours in a nitrogen stream from a nitrogen introduction tube. It was. After the reaction, the obtained polyester polyol (B3) was a white solid at room temperature, and had an acid value of 0.40 and a hydroxyl value of 59.9.

[Synthesis Example 4]
A 2-liter four-necked flask was charged with 251 parts of 1,3PD, 477 parts of EG, 59 parts of TMP, 1243 parts of SucA, 0.06 part of tetrabutyl titanate, and reacted at 220 ° C. for 24 hours in a nitrogen stream from a nitrogen inlet tube. It was. After the reaction, the obtained polyester polyol (B4) was a white solid at room temperature, and had an acid value of 0.35 and a hydroxyl value of 60.3.

[Synthesis Example 5]
A 2-liter four-necked flask is charged with 85 parts of 1,3PD, 625 parts of EG, 61 parts of TMP, 1266 parts of SucA, 0.06 parts of tetrabutyl titanate, and reacted at 220 ° C. for 24 hours in a nitrogen stream from a nitrogen introduction tube. It was. After the reaction, the obtained polyester polyol (B5) was a white solid at room temperature, and had an acid value of 0.32 and a hydroxyl value of 59.1.

[Synthesis Example 6]
A 2-liter four-necked flask was charged with 613 parts of diethylene glycol (hereinafter abbreviated as “DEG”), 239 parts of EG, 52 parts of TMP, 1079 parts of SucA, and 0.06 part of tetrabutyl titanate. The reaction was carried out at 220 ° C. for 24 hours. After the reaction, the obtained polyester polyol (B6) was a pale yellow viscous liquid having an acid value of 0.41 and a hydroxyl value of 60.2.

[Synthesis Example 7]
In a 2 liter four-necked flask, 577 parts of DEG, 1,4-butylene glycol (hereinafter abbreviated as “1,4BG”) 327 parts, 49 parts of TMP, SucA 1011, 0.06 part of tetrabutyl titanate, nitrogen introduction The reaction was carried out at 220 ° C. for 24 hours under a nitrogen stream from the tube. After the reaction, the obtained polyester polyol (B7) was a pale yellow viscous liquid having an acid value of 0.41 and a hydroxyl value of 60.7.

[Synthesis Example 8]
In a 2-liter four-necked flask, 560 parts of DEG, 1,5 pentanediol (hereinafter abbreviated as “1,5PD”) 366 parts, 49 parts of TMP, 979 parts of SucA, 0.06 part of tetrabutyl titanate, nitrogen introduction The reaction was carried out at 220 ° C. for 24 hours under a nitrogen stream from the tube. After the reaction, the obtained polyester polyol (B8) was a pale yellow viscous liquid having an acid value of 0.41 and a hydroxyl value of 60.2.

[Synthesis Example 9]
A 2-liter four-necked flask is charged with 369 parts of 1,3PD, 301 parts of EG, 53 parts of TMP, 1339 parts of adipic acid (hereinafter abbreviated as “AA”), 0.06 part of tetrabutyl titanate, and nitrogen from a nitrogen introduction tube. The reaction was carried out at 220 ° C. for 24 hours under an air stream. After the reaction, the obtained polyester polyol (B9) was a white solid at room temperature, and had an acid value of 0.30 and a hydroxyl value of 59.0.

[Examples 1 to 5] and [Comparative Examples 1 to 4]
<Molding by one-shot method>
As Examples 1 to 5 and Comparative Examples 1 to 4, respectively, Hyprox 1225 (Crude MDI, manufactured by DIC Corporation) as a polyisocyanate (A), and polyester polyols (B1) obtained in Synthesis Examples 1 to 9 were used. (B9) was mixed and stirred at a blending ratio of [NCO] / [OH] = 1.00 equivalent ratio to prepare a urethane elastomer composition for printing rolls as a mixed solution. The urethane elastomer composition for a printing roll was poured into a sheet-shaped mold having a thickness of 2 mm and a cylindrical mold having a diameter of 4.0 cm and a thickness of 1.2 cm.
The molds were heated in a hot air dryer at 120 ° C. for 2 hours to be primarily cured, and further cured at 110 ° C. for 16 hours to produce a thermosetting polyurethane molded product for a printing roll. This molded product is subjected to the following test.

Abbreviations in Table 1 and Table 2 mean the following.
EG; ethylene glycol SucA; succinic acid 1,3PD; 1,3-propanediol 1,4BG; 1,4-butanediol DEG; diethylene glycol 1,5PD; 1,5-pentanediol TMP; trimethylolpropane MEK; methyl ethyl ketone AA Adipic acid

  Since the urethane elastomer composition for printing rolls of the present invention is excellent in both solvent resistance and water resistance, the printing roll of the present invention formed by using the urethane elastomer composition for printing rolls is a solvent-based ink. In addition, it is suitable for printing using water-based ink, and is extremely useful for printing rolls used for various printing such as gravure printing, flexographic printing, and offset printing.

Claims (5)

A urethane elastomer composition obtained by using a polyisocyanate (A) and a polyester polyol (B), wherein the polyester polyol (B) essentially comprises 1,3-propanediol as a hydroxyl group-containing difunctional component, A urethane elastomer composition for printing rolls characterized in that succinic acid is essential as a group-containing component. The urethane elastomer composition for printing rolls according to claim 1, wherein the hydroxyl group-containing difunctional component is 1,3-propanediol and ethylene glycol. In the polyester polyol (B), the composition of the hydroxyl group-containing difunctional component is ethylene glycol / 1,3-propanediol = 10/90 to 90/10 molar ratio, and the hydroxyl group-containing bifunctional component / hydroxyl group-containing polyfunctional component. The urethane elastomer composition for printing rolls according to claim 1, wherein the functional component is 90/10 to 99/1 molar ratio. The urethane elastomer composition for printing rolls according to claim 3, wherein trimethylolpropane is used as the hydroxyl group-containing polyfunctional component in the polyester polyol (B). A printing roll formed by molding the urethane elastomer composition for a printing roll according to claim 1.