JP2002226540A - Polyurethane composition for roll - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyurethane composition for rolls which scarcely cause slipping and the like and have high frictional coefficients. SOLUTION: This polyurethane composition for the rolls, comprising an isocyanate group-terminated prepolymer obtained by reacting an organic polyisocyanate with a polyethr polyol, and a polyol having a number-average mol.wt. of <=500, is characterized in that the polyether polyol comprises (A) polyoxytetramethylene glycol having a number-average mol.wt. of 1,000 to 4,000 and the functional group number of 2.0 to 3.0 and (B) a polyoxypropylene polyol having a number-average mol.wt. of 1,000 to 4,000 and the functional group number of 1.0 to 6.0 in a (A):(B) weight ratio of 5:95 to 95:5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyurethane composition used for a roll, which is an industrial equipment part requiring a high coefficient of friction.

[0002]

2. Description of the Related Art Generally, rolls, which are industrial equipment parts made of urethane elastomer, are used as a raw material for isocyanate in diphenylmethane diisocyanate (hereinafter referred to as MDI).
And the like, and as a polyol raw material, a polyester diol such as ethylene adipate, butylene adipate, or caprolactone, or a polyether diol such as polyoxytetramethylene glycol is used. Using 4-butanediol (hereinafter abbreviated as 1,4-BD), trimethylolpropane (hereinafter abbreviated as TMP), or a mixture thereof, by a one-shot method, a semi-one-shot method, a prepolymer method, or the like The method of using the obtained polyurethane elastomer for industrial equipment parts is used, and isocyanate (hereinafter referred to as NCO)
A prepolymer method of curing a group-terminated prepolymer with a polyol is widely used.

[0003] In the prior art, the coefficient of friction is low,
In the case where the paper is used in a roll or the like due to slippage or the like, there have been problems such as that paper feeding may not be performed smoothly.

Therefore, in order to improve the friction coefficient, Japanese Patent Application Laid-Open No. 50-58149 discloses that
There has been proposed a method of vulcanizing a rubber raw material containing a kind of liquid rubber as a main component with the same cross-linking agent, and JP-A-61-26613 proposes a roll made of polyurethane having a specific group in a molecule. I have.

[0005]

However, in Japanese Patent Application Laid-Open Nos. 50-58149 and 61-26613, there is a problem in that the friction coefficient is still low, slippage occurs, and the workability is poor. .

An object of the present invention is to provide a polyurethane composition for rolls having a high coefficient of friction that solves such problems.

[0007]

Means for Solving the Problems The present inventor has conducted various studies to achieve the above-mentioned object, and as a result, it has been found that the problem can be solved by using polyoxytetramethylene glycol and polyoxypropylene polyol at a specific mixing ratio. Headings,
The present invention has been completed. That is, the present invention is the following three.

Invention 1: In a polyurethane composition for a roll comprising a prepolymer having a terminal isocyanate group obtained by reacting an organic polyisocyanate and a polyether polyol, and a polyol having a number average molecular weight of 500 or less, the composition of the polyether polyol Has a number average molecular weight of 1,000 to 4,000 and a number of functional groups of 2.0 to
3.0 polyoxytetramethylene glycol (A), a number average molecular weight of 1,000 to 4,000, and a number of functional groups of 1.
A polyoxypropylene polyol (B) having a mass ratio of (A) :( B) = 5 to 6.0;
5:95 to 95: 5.

Invention 2: A prepolymer having terminal isocyanate groups obtained by reacting an organic polyisocyanate with a polyether polyol, and a polyurethane composition for a roll comprising a polyether polyol and a polyol having a number average molecular weight of 500 or less, The composition of the polyether polyol in the entire product is such that the number average molecular weight is 1,000 to 4,000 and the number of functional groups is 2.0 to 3.0.
With polyoxytetramethylene glycol (A) having a number average molecular weight of 1,000 to 4,000 and a functional group number of 1.5 to
6. A polyoxypropylene polyol (B) having a mass ratio of (A) :( B) = 5: 9.
The composition, wherein the composition is 5 to 95: 5.

Invention 3: A polyurethane composition for a roll comprising an organic polyisocyanate, a polyether polyol, and a polyol having a number average molecular weight of 500 or less,
The composition of the polyether polyol is a polyoxytetramethylene glycol (A) having a number average molecular weight of 1,000 to 4,000 and a functional group of 2.0 to 3.0 and a number average molecular weight of 1,000 to 4,000. The number of functional groups is 1.5 to 6.
A polyoxypropylene polyol (B) having a mass ratio of (A) :( B) = 5: 95 to
95: 5. The above composition, wherein the composition is 95: 5.

[0011]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in more detail. As the organic polyisocyanate used in the present invention, any of those generally used for polyurethane elastomers can be used. Specifically, m-phenylene diisocyanate, p-phenylene diisocyanate, 2,4′-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 4,4′-diphenylmethane diisocyanate (hereinafter abbreviated as MDI), 2,4-triene Aromatic diisocyanates such as diisocyanate (hereinafter abbreviated as TDI), 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4-4'-diphenyl ether diisocyanate, 1,3-xylene diisocyanate, 1,4- Xylene diisocyanate,
Aromatic diisocyanates such as tetramethylxylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2
-Propylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate,
Aliphatic diisocyanates such as 1,3-butylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, 2,6-diisocyanate methylcaproate, 1,3-cyclopentene diisocyanate,
1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, 4,4'-methylenebis (cyclohexyl isocyanate), methyl-2,4-cyclohexane diisocyanate, methyl Alicyclic diisocyanates such as -2,6-cyclohexanediisoanate and 1,4-bis (isocyanatomethyl) cyclohexane, and modified carbodiimide, biuret, allophanate, dimer and trimer of these diisocyanates Or polymethylene polyphenyl polyisocyanate (crude MDI, polymeric MDI) and the like. Of these, aromatic isocyanates are preferred, and MDI and TDI are more preferred. These can be used alone or in combination of two or more.

The polyether polyol used in the present invention is polyoxytetramethylene glycol (hereinafter referred to as P
TMG) (A) and polyoxypropylene glycol (hereinafter abbreviated as PPG) (B).

PTMG (A) has a number average molecular weight of 1,0.
00 to 4,000, and the number of functional groups (= the number of hydroxyl groups in one molecule) is 2.0 to 3.0. Also, PPG
(B) has a number average molecular weight of 1,000 to 4,000 and a functional group number (= the number of hydroxyl groups in one molecule) of 1.5 to 6.0.

The mass ratio between PTMG (A) and PPG (B) is (A) :( B) = 5: 95-95: 5,
(A) :( B) = 60: 40 to 90:10 is preferred.
In the case of PTMG alone, the coefficient of friction is low. In the case of PPG alone, the coefficient of friction is similarly low and other physical properties are also poor. In addition, it is preferable that PTMG is the majority from other physical properties. Note that PTMG (A) and P
The mass ratio of PG (B) may finally be within the above range.

The prepolymer having an NCO group at a molecular terminal used in the present invention is synthesized by the following method.
That is, the organic polyisocyanate and the polyether polyol may be reacted at such a ratio that the NCO groups of the organic polyisocyanate are excessive with respect to the hydroxyl groups (OH groups) of the polyether polyol. Specifically, the ratio of the equivalent ratio (NCO group / OH group) of the organic polyisocyanate to the polyether polyol is preferably 1.2 to 4.0, more preferably 1.5 to 3.0. To react. In this reaction, if necessary, a known urethanization catalyst such as an organometallic catalyst or an amine catalyst may be used. The NCO content of the obtained prepolymer having an NCO group at the molecular terminal is preferably from 0.3 to 35% by mass, more preferably from 0.5 to 15% by mass, particularly preferably from 1 to 10% by mass. .

As the polyol having a number average molecular weight of 500 or less used in the present invention, specifically, ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-BD, 1,3 -Butanediol, 1,
5-pentanediol, 1,6-hexanediol, 3
-Methyl-1,5-pentanediol, neopentyl glycol, 1,8-octanediol, 1,9-nonanediol, diethylene glycol, cyclohexane-
Examples include 1,4-diol, cyclohexane-1,4-dimethanol, dimer acid diol, TMP, glycerin, hexanetriol, quadrol or bisphenol A ethylene oxide or propylene oxide adduct. The preferred low molecular polyol is a blend of a polyfunctional polyol having three or more functionalities and a diol, and a blend of TMP and 1,4-BD is more preferred.

The roll is manufactured by a prepolymer method, a semi-one-shot method, or a one-shot method. The prepolymer method is a method of reacting a prepolymer having an NCO group at a molecular terminal with a low-molecular polyol. The semi-one-shot method is a method in which a prepolymer having an NCO group at a molecular terminal is reacted with a mixed polyol of a high molecular polyol and a low molecular polyol. The one-shot method is a method of reacting a mixed polyol of an organic polyisocyanate, a high molecular polyol and a low molecular polyol. Here, the term "low-molecular" refers to a number-average molecular weight of 500 or less, and the term "high-molecular" refers to a number-average molecular weight of 1,000 or more.

The prepolymer containing a terminal NCO group used in the prepolymer method includes an organic polyisocyanate and PT.
It is obtained by reacting a polyether polyol consisting of MG (A) and PPG (B).

Terminal NC used in semi-one-shot method
The O group-containing prepolymer comprises an organic polyisocyanate,
It is obtained by reacting a polyether polyol comprising at least one of PTMG (A) and PPG (B). The prepolymer containing a terminal NCO group used in the preferred semi-one-shot method is obtained by reacting an organic polyisocyanate and a polyether polyol having at least PPG (B). In addition,
The composition ratio of PTMG and PPG may be finally within the range of the composition ratio. For example, the polyether polyol used for the prepolymer is a blend of PTMG and PPG, and the polyether polyol used for the curing agent is PT
The blend of MG and PPG or the combination of PTMG alone may be used. The polyether polyol used for the prepolymer may be PPG alone, and the polyether polyol used for the curing agent may be the combination of PTMG alone.

A method for manufacturing a roll will be described. In the present invention, a method in which a two-pack type polyurethane on the isocyanate side and the polyol side is used is suitable. The isocyanate side in the prepolymer method is a terminal NCO group-containing prepolymer, and the polyol side is a low molecular polyol. In the semi-one-shot method, the isocyanate side is a prepolymer having a terminal NCO group, and the polyol side is a mixture of a low molecular polyol and a high molecular polyether polyol. In the one-shot method, the isocyanate side is an organic polyisocyanate, and the polyol side is a mixture of a low molecular weight polyol and a high molecular weight polyether polyol.

In the reaction between the isocyanate side and the polyol side, the equivalent ratio (NCO group / OH group) is preferably 0.1.
It is performed by adding and mixing at a ratio of 8 to 1.5. When both the isocyanate side and the polyol side are solids at room temperature or have high viscosity, they are heated in advance to be liquid and then mixed and stirred. After degassing the liquid mixture under reduced pressure as necessary, inject the liquid mixture into a mold,
For example, it is cured by heating to about 80C to 140C. In this reaction, a known urethanization catalyst or trimerization catalyst can be used in combination, if necessary. The mold is preferably preheated to, for example, about 80C to 140C. The reactant is usually heat-cured for about 20 minutes to several hours, and then can be released from the mold. However, it is preferable to heat the molded article after the release, and to heat the same at the above-mentioned temperature for 4 to 24 hours before and after the release. Preferably, it is cured. If necessary, aging is performed at room temperature for about 3 to 7 days. by this,
Rolls having a JISA hardness of 50 to 80 are manufactured.

The polyurethane composition for a roll of the present invention may contain, if necessary, a plasticizer, an antifoaming agent, a leveling agent, a matting agent, a flame retardant, a thixotropic agent, a tackifier, a thickener, a lubricant,
Known additives such as antistatic agents, surfactants, reaction retarders, dehydrating agents, antioxidants, ultraviolet absorbers, hydrolysis inhibitors, weather stabilizers, dyes, inorganic pigments, organic pigments, extender pigments, etc. are appropriately used. Can be blended.

[0023]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

[Synthesis of NCO Group-Containing Urethane Prepolymer] Synthesis Example 1 PTMG (PTG-2000S) was added to 226 g of MDI.
N, number average molecular weight = 2,000, Hodogaya Chemical Industry Co., Ltd.) (542 g) was added thereto, and the mixture was stirred and reacted at 80 ° C. for 2 hours under a nitrogen atmosphere. The NCO group content during the reaction was measured by titration, and when the decrease of the NCO group content stopped,
(PP-2000, number average molecular weight = 2,000, manufactured by Sanyo Chemical Industries) was added, and the mixture was stirred and reacted at 80 ° C. for 4 hours under a nitrogen atmosphere. The NCO group content during the reaction was measured by titration, and when the decrease in the NCO group content stopped, the reaction was terminated to produce a prepolymer (A) having an NCO content of 4.3% by mass. The results are summarized in Table 1.

Synthesis Examples 2 to 12 Using the raw materials shown in Table 1, NC
(L) was prepared from a prepolymer (B) containing an O group. The results are summarized in Table 1.

[0026]

[Table 1]

Synthesis 1 to 12, in Table 1 MDI: 4,4'-diphenylmethane diisocyanate PTG-2000SN manufactured by Nippon Polyurethane Industry: Polytetramethylene ether glycol manufactured by Hodogaya Chemical Industries, number average molecular weight = 2,000 PP-2000: Polyoxypropylene diol, manufactured by Sanyo Chemical Industries, number average molecular weight = 2,000 Exenol 2020: polyoxy (ethylene / propylene) diol, manufactured by Asahi Glass, number average molecular weight = 2,000 CM-211: polyoxy (ethylene / propylene) diol, Asahi Denka Kogyo Manufactured by Asahi Denka Kogyo Co., Ltd., number average molecular weight = 3,000 PBA-2000: polybutylene diol adipate manufactured by Nippon Polyurethane Industry, number average molecular weight = 2 000

Example 1 Prepolymer Method 200 g of the prepolymer (A) was preheated to 85 ° C., and 8.8 g of a mixed crosslinking agent composed of 1,4-BD and TMP was added thereto.
Was added and stirred and mixed so as to be uniform. This was quickly degassed under reduced pressure and then preheated to 130 ° C.
The mixture was poured into a roll mold and a sheet production mold each having a size of 5 mm, an inner diameter of 8 mm, and a length of 10 mm, and heated at the same temperature for 1 hour. Thereafter, the mold was released from the mold, and further heated and cured at 100 ° C. for 10 hours. This was further aged for 7 days to obtain a roll and a sheet for measuring physical properties. At this time, the molar ratio of NCO groups / OH groups was 1.05.

Examples 2 to 6 and Comparative Examples 1 to 3 Rolls and sheets for measuring physical properties were produced in the same manner as in Example 1 using the respective raw materials shown in Tables 2 and 3, and the various physical properties were measured. . The results are summarized in Tables 2 and 3.

Example 7 Semi-one-shot method 150 g of prepolymer (G) was preheated to 85 ° C., and 61.2 g of PTG-2000SN and PP-200 were added thereto.
0 and 20.7 g of a mixed cross-linking agent were added, and the mixture was stirred and mixed so as to be uniform. After quickly degassing and degassing under reduced pressure, the mixture was poured into a roll mold and a sheet-forming mold having an outer diameter of 15 mm, an inner diameter of 8 mm, and a length of 10 mm, which had been preheated to 130 ° C., and heated at the same temperature for 1 hour. Thereafter, the mold was released from the mold, and further heated and cured at 100 ° C. for 10 hours. This was further aged for 7 days to obtain a roll and a sheet for measuring physical properties. At this time, the molar ratio of NCO group / OH group was 1.
05. The results are summarized in Table 3.

Examples 8 and 9 Using the raw materials shown in Table 3, rolls and sheets for measuring physical properties were produced in the same manner as in Example 7, and the various physical properties were measured. The results are summarized in Table 3.

Example 10 One-shot method Of the raw materials shown in Table 3, PTG-2000SN, PP-
2000, after premixing the mixed cross-linking agent, degassing was performed under reduced pressure, and using the mixture of MDI and MDI, injection was performed in the same manner as in Example 1 to produce a roll and a sheet for measuring physical properties. It was measured. The results are summarized in Table 3.

Examples 1 to 10, Comparative Examples 1 to 3, Tables 2 and 3
In MDI: 4,4'-diphenylmethane diisocyanate Nippon Polyurethane Industry PTG-2000SN: polytetramethylene ether glycol Hodogaya Chemical Industry, number average molecular weight = 2,000 PP-2000: polyoxypropylene diol Sanyo Chemical Industry, number Average molecular weight = 2,000 Mixed crosslinking agent: 1,4-BD / TMP = 6/4 (mass ratio) Hardness: Measured according to JIS K7312 Friction Coefficient: Initial value and after sending 50,000 sheets of plain paper Value Abrasion resistance: Reduction in outer diameter after sending 50,000 sheets of plain paper

[0034]

[Table 2]

[0035]

[Table 3]

[0036]

In general, the softer the roll, the higher the friction coefficient. Therefore, in the prior art, the hardness was reduced by adding a plasticizer or the like to increase the friction coefficient. For this reason, there was a problem that a plasticizer bleeds and slippage occurs. The roll of the present invention has a higher coefficient of friction and a higher abrasion resistance than those reported by the methods described so far. With less workability.

Continued on the front page F term (reference) 4J034 BA03 BA07 CB03 CB04 CC03 CC26 CC61 CC65 DB04 DB05 DC50 DG04 DG06 DG08 HA01 HA02 HA06 HA07 HA09 HA11 HC03 HC12 HC13 HC22 HC71 HC73 QA05 QB13 RA14 RA16 RA19

Claims (3)

[Claims] 1. A polyurethane composition for rolls comprising a terminal isocyanate group-containing prepolymer obtained by reacting an organic polyisocyanate and a polyether polyol, and a polyol having a number average molecular weight of 500 or less, wherein the polyether polyol has a structure. Having a number average molecular weight of 1,000 to 4,000 and a number of functional groups of 2.0 to 3.0.
With polyoxytetramethylene glycol (A) having a number average molecular weight of 1,000 to 4,000 and a functional group number of 1.5 to
6. A polyoxypropylene polyol (B) having a mass ratio of (A) :( B) = 5: 9.
The composition, wherein the composition is 5 to 95: 5. 2. A polyurethane composition for a roll comprising a terminal isocyanate group-containing prepolymer obtained by reacting an organic polyisocyanate and a polyether polyol, and a polyether polyol and a polyol having a number average molecular weight of 500 or less. The configuration of the polyether polyol as a whole has a number average molecular weight of 1,
Polyoxytetramethylene glycol (A) having 2,000 to 4,000 and having 2.0 to 3.0 functional groups and polyoxytetramethylene glycol having a number average molecular weight of 1,000 to 4,000 and 1.5 to 6.0 functional groups It is composed of propylene polyol (B), and its mass ratio is (A) :( B) = 5: 95-9.
5: 5. The above composition, wherein the composition is 5: 5. 3. A polyurethane composition for rolls comprising an organic polyisocyanate, a polyether polyol and a polyol having a number average molecular weight of 500 or less, wherein the polyether polyol has a number average molecular weight of 1,000.
Polyoxytetramethylene glycol (A) having a number of functional groups of 2.0 to 3.0 and a number average molecular weight of 1,
It is composed of polyoxypropylene polyol (B) having 000 to 4,000 and having 1.5 to 6.0 functional groups, and its mass ratio is (A) :( B) = 5: 95 to 95: 5.
The composition, which is: