JPS63297416A - Thermosetting urethane elastomer composition - Google Patents

Abstract

PURPOSE:To provide the titled composition composed of a urethane prepolymer, an organic polyamine and a specific urethane compound, capable of lowering the hardness of a urethane elastomer without lowering other physical properties and suitable for tire, roll, belt and various other industrial goods. CONSTITUTION:The objective composition is composed of (A) a urethane prepolymer (preferably having an NCO equivalent of 500-2,000), (B) an organic polyamine (most preferably 3,3-dichloro-4,4-diaminodiphenylmethane, etc.) and (C) a urethane compound free from isocyanate group, having 1-3 urethane bonds in the molecule and produced by reacting an organic isocyanate with a monool having an average molecular weight of 200-10,000 (preferably having a viscosity of 1,000-7,000cps at 25 deg.C).

Description

Detailed Description of the Invention <Industrial Application Field> The present invention is directed to urethane prepolymers (I), organic polyamines (II), and urethane compounds (I[ ) Concerning the thermosetting urethane elastomer composition, it specifically contains a urethane compound without reactive groups obtained by reacting a monool with an average molecular weight of N200 to to, ooo without deteriorating the physical properties. (Relating to a thermosetting urethane elastomer composition that reduces the hardness of the urethane elastomer.)

<Prior art and its problems> Thermosetting urethane elastomers have high strength, wear resistance,
Because it has excellent properties such as chemical resistance and ozone resistance, it is widely used to fill the gap between rubber and steel. Examples include solid tires, various industrial rolls, hammers, machine pads, drive belts, pump housings, packings, etc.

Methods for preparing thermosetting urethane elastomers include the well-known pulcolan treatment method developed by Bayer, and the method using prepolymer and 3,3'-dichloro-4, developed by DuPont. A method using 4'diaminodiphenylmethane (abbreviated as MOCA) in combination with a chain extender is known.

These two treatments have their own characteristics, but
The latter DuPont treatment, which is a combination of telepolymer and MOCA, is generally widely used because urethane elastomers can be prepared more easily.

In the latter MOCA curing method, a curing method using an organic polyamine, the hardness of the urethane elastomer to be prepared can be adjusted by adjusting the molecular weight of the urethane prepolymer used each time, or by using a chain extender. The hardness is reduced by combining the organic polyamine with a short chain polyol, or by mixing a small amount of plasticizer into the elastomer.

The method of adjusting the hardness of the resulting urethane elastomer by adjusting the molecular weight of the urethane prepolymer uses a stoichiometric amount of organic polyamine according to the molecular weight, so it is possible to reliably obtain an elastomer with the desired hardness. It is possible. However, it is necessary to prepare a separate urethane prepolymer to slightly lower the hardness, which means that a very wide variety of products is required, which complicates the process and also has the disadvantage that workers avoid using it. .

Organic polyamine and triisopropanolamine, 1.4
- In combination with a urethane prepolymer using short chain polyols such as butanediol, bisphenol A with alkylene oxide added, and other similar low molecular weight polyols as a chain extender. When used, it is extremely effective in reducing hardness, but it also has the drawback of significantly reducing physical properties and sometimes losing its characteristics as a urethane elastomer.

In the process of curing urethane prepolymer with organic polyamine, common plasticizers such as dioctyl phthalate, dibutyl phthalate, tricresyl phosphate, etc., or dibenzoates obtained from diol and benzoic acid that are compatible with urethane prepolymer are used. The method of lowering the hardness by adding plasticizers is the easiest to use compared to the above two methods, but when adding a large amount of ordinary plasticizers, they bleed from the elastomer violently, and on the other hand, it is difficult to reduce the hardness by adding a large amount of plasticizers. The effect is poor at the added amount. Dibenzoate plasticizers have less bleeding than the former plasticizers and have a greater effect on reducing hardness, but since they have a small amount of hydroxyl groups in their composition, they can be used in combination with the above-mentioned organic polyamines and short-chain diols. Similar to the disadvantages, there is also the problem of deterioration of physical properties.

<Means for solving the problem> In order to obtain a desired hardness of urethane elastomer, it is necessary to prepare a wide variety of urethane prepolymers, or to use a short chain polyol as a chain extender at the expense of performance. etc. have been adopted.

The inventors used a small variety of urethane prepolymers to
As a result of intensive research to easily obtain thermosetting urethane elastomers without impairing the performance of urethane,
When a urethane compound (I[) having no isocyanate group and having 1 to 3 urethane bonds in the molecule obtained by reacting a monool with an average molecular weight of 1t200 to 10.000 with an organic isocyanate is used as a hardness modifier. Good compatibility with urethane prepolymer (1),
A urethane elastomer composition containing this urethane compound (I[) and obtained using a urethane prepolymer (I) and an organic polyamine (II) as a chain extender can be easily prepared as desired by preparing several types of urethane prepolymers. The present invention was completed based on the discovery that a urethane elastomer with a hardness of reached.

That is, the present invention is obtained by reacting an organic isocyanate with a urethane prepolymer (I), an organic polyamine (II), and a monool having an average molecular weight of 200 to 10,000, and has 1 to 3 urethane bonds in the molecule. The object of the present invention is to provide a thermosetting urethane elastomer composition comprising a urethane compound (III) having no isocyanate groups.

Structure> The urethane prepolymer (1) of the present invention has an isocyanate group at the molecular end, and the polyol and excess organic polyisocyanate are mixed in an equivalent ratio of NGOloH of 1.
3 to 2.2, preferably 1.5 to 2.05, obtained by a conventional reaction, and has an NGO equivalent of 400 to 2,600.
, preferably from 500 to 2000. N.G.O.l.
If the oH equivalent ratio is less than 1.3, the viscosity of the prepolymer will become too high, and if it is greater than 2.2, the organic diisocyanate remaining as unreacted will accelerate the reaction with the chain extender and shorten the pot life. Therefore, it is not desirable. Polyols used in the urethane prepolymer (1) include polyester polyols and polyester polyols.

As the polyether polyol mentioned here, any polyether polyol conventionally used in the production of polyurethane can be used, such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, .4
- Polyol monomers such as butanediol, 1,6-hexanediol, neopentyl glycol, bisphenol A, 1-limethylolethane, trimethylolpropane, glycerin, and alkylene oxides, such as ethylene oxide, propylene oxide, butylene oxide. , styrene oxide, etc. alone, copolymers such as polytetramethylene ether glycol obtained by ring-opening polymerization of tetrahydrofuran, or polyether polyols made of mixtures of these polymers. can.

Further, the polyester polyol can be obtained by a condensation reaction between a polyol monomer and a dibasic acid, and a ring-opening polymerization reaction between a short chain polyol and a lactone.

As a polyol monomer, as an aliphatic polyol,
For example, ethylene glycol, diethylene glycol,
Propylene glycol, butylene glycol, benzyl glycol, hexane glycol, trimethylolpropane, pentaerythritol, aromatic polyols such as bisphenol A, N,N'-dihydroxypropylaniline, N,N'-dihydroxyethylaniline, bis Hydroxyethoxybenzene, 1.4
-Hydroxybenzene, alicyclic polyol:
For example, 1,4-hydroxycyclohexane, 2.2
'Bis(hydroxycyclohexyl)propane, spiroglycol, etc. In addition, polybutadiene polyol and the like are also used.

Dibasic acids include aliphatic dibasic acids such as succinic acid,
Geltar acid, adipic acid, pimelic acid, speric acid,
Examples of the alicyclic dibasic acids include azelaic acid, sepatic acid, dodecanedicarboxylic acid, and cyclohexyldicarboxylic acid.

Lactone compounds include ε-caprolactone, γ-
Examples include butyl lactone and valerolactone.

These polyester polyols can be obtained by a condensation reaction by mixing two or more types of short chain polyols and/or dibasic acids, or can be obtained by a cocondensation polymerization reaction of a dibasic acid and a lactone. , two or more types of polyester polyols or other polyester polyols with different molecular weights may be mixed. Furthermore, polyether polyols and polyester polyols may be mixed as long as they have good compatibility. The polyol used preferably has an average number of functional groups of 2. If the average number of functional groups is less than 2, it will be difficult to increase the molecular weight, and if it is more than 2, the crosslinking density will increase, and the elastomers obtained from these will have insufficient elongation and will be given brittle properties.

As the organic polyisocyanate, any polyisocyanate having 2 to 3 NCO groups used in the production of polyurethane can be used, such as 1,5-naphthylene diisocyanate, 4,4' diphenylmethane diisocyanate, tridene diisocyanate, hexane diisocyanate, etc. Methylene diisocyanate, isophorodiisocyanate, xylylene diisocyanate, dimeryl diisocyanate, 2.4
/ 2.6 (isomer ratio 80/20.65/35 and 1
0010)-tolylene diisocyanate, etc.
Preferable examples include tolylene diisocyanate and xylylene diisocyanate.

These can be used alone or as a mixture. Further, prepolymers containing terminal isocyanate groups obtained by reacting the polyether polyol or polyester polyol with an organic polyisocyanate may be used alone or in mixtures thereof.

Organic polyamine (n) used as a curing agent in the present invention
Examples include 3,3-dichloro-4,4-diaminodiphenylmethane (MOC^), 4,4-diaminodiphenylmethane (referred to as DAM'), 1,5-diaminonaphthylene, trimethylene-bis(4-aminobenzoate)
Ihara Chemical Industry Co., Ltd., product name CUA-4),
3.5-diamino-4-chlorophenyl isobutyl ester (Bayer Co Ltd1 trade name no-1604)
Diamines such as MOC are particularly preferred.
＾ is mentioned. In addition, alcohol amines such as triethanolamine and triisopropane may be used together in an amount of 0 to 20% by weight based on the polyamine, as these polyamines (II) are superior to other ethylene glycols and trimethylolpropanes. This is thought to be due to the formation of urea bonds and billet bonds.

Urethane metal (I) obtained by reacting a monool with an average molecular weight of 200 to 10,000 and an organic isocyanate
[[) has substantially no hydroxyl group or isocyanate group, and has a viscosity of 700 to 10.000 c at 25°C
ps, preferably 1000 to 7000 cps. The monol is a polyether monol or polyester monol having one hydroxyl group obtained by polymerizing a monomer having active hydrogen, and has a number average molecular weight of 200 to 10.000.

Polyether monools are monohydric alcohols with oxides added to monomers having one active hydrogen atom, such as aliphatic saturated alcohols such as methyl alcohol, ethyl alcohol, and butyl alcohol; cyclopentanol. , alicyclic alcohols such as dimethylcyclohexanol; aromatic alcohols such as benzyl alcohol; carbocyclic alcohols such as furfuryl alcohol; phenolic alcohols such as phenol and cresol; aliphatic monocarbons such as formic acid and acetic acid. For example, oxides such as ethylene oxide, propylene oxide, butylene oxide, and styrene oxide are polymerized alone to monomers having one active hydrogen atom in the molecule, such as acids; aromatic monocarboxylic acids such as benzoic acid; or a mixture thereof.

Polyester monools include -hydric alcohols, -
Basic acids, condensates of polybasic acids and polyhydric alcohols are used; for example, polybasic acids such as maleic acid, fumaric acid, adipic acid, phthalic acid alone or in mixtures with ethylene glycol, diethylene glycol, propylene glycol,
Dipropylene glycol, 1,3-butanediol, 1
．． Polyhydric alcohols such as 4-butanediol and 1,6-hexanediol alone or in mixtures, monohydric alcohols such as methyl alcohol, ethyl alcohol, ethyl alcohol, cyclopentanol, formic acid, acetic acid, etc., or -basic acids. The resulting polyester monool has one OH group at its terminal. This will result in various mixtures during manufacturing, so care must be taken.

Furthermore, the terminals obtained by ring-opening and addition polymerizing lactones such as ε-caprolactone to the monohydric alcohols, -valent carboxylic acids, and monomers having one active hydrogen atom in their low molecules. Examples include polyester monools having one OH group.

The organic isocyanate has 1 to 1 isocyanate group.
Any of the three isocyanates can be used, for example, methyl isocyanate, ethyl isocyanate, phenyl isocyanate, parachlorophenylisocyanate, 2,4-tolylene diisocyanate, 2.6-tolylene diisocyanate, 2.4/2.6 = 65
/35 (wt)) lylene diisocyanate, 2.
4 /2.6-80 /20 (wt)) lylene diisocyanate, 4.4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, phenylene diisocyanate), 1.5-naphthalene diisocyanate, metaxylylene diisocyanate, hydrogenated tri- diisocyanate, hydrogenated 4゜4'-diphenylmethane diisocyanate, crude tolylene diisocyanate,
Examples include polymethylene polyphenylisocyanate. These can be used alone or as a mixture.

Furthermore, organic isocyanates consisting of prepolymers containing terminal isocyanate groups obtained by reacting polyether polyols or polyester polyols used in polyurethane production with organic polyisocyanates, alone or in mixtures thereof, can also be used, but the viscosity Many of them are expensive, so choose one that is suitable for your purpose.

The urethane compound (I [I) obtained by reacting the monool of the present invention with an organic isocyanate has an active hydrogen atom (for example, a hydroxyl group, etc.) or an isocyanate group at the end of the molecule, and one urethane bond in the molecular chain. It is a urethane compound having ~3. This reaction is carried out in an equivalent ratio of NGOlof (preferably 1.1/1.0 to 1.0/1.1), for example, using a slight excess of organic isocyanate, which remains after the urethanization reaction is completed. Free isocyanate groups can be obtained by capping inocyanate groups with -hydric alcohols such as methanol, ethanol, butanol, propatool, pentanol, hexanol, heptatool, etc., or with a slight excess of monool. and an organic isocyanate.In particular, the compound produced by the above-mentioned method of reacting with a slight excess of the organic isocyanate and blocking the remaining isocyanate groups with a monohydric alcohol has fewer impurities.
This is preferable because it results in less bleeding.

The urethane compound (I) of the present invention is used by being added in advance to the urethane prepolymer (1) or the organic polyamine (II), or both. If the urethane prepolymer (1) used at this time is based on polyether polyol, the urethane compound (1) used from the viewpoint of compatibility (
I[[) is also preferably a polyether-based prepolymer.On the other hand, if it is a polyester polyol-based prepolymer, it is preferable to select a polyester-based urethane compound (III).The content of the urethane compound (III) in the urethane elastomer is 5 to 50% by weight, preferably 10 to 40% by weight. If the content increases, a bleeding phenomenon occurs in the elastomer, which is undesirable.

When mixing the components (I), (n), and (I[[), if the urethane compound (I[[) is added to the urethane prepolymer (I) in advance, the viscosity of the urethane compound If it is lower than the urethane prepolymer, it is also effective as a viscosity reducing agent and is useful for improving workability, so it is preferable.

When adding the urethane compound (I[[) to the organic polyamine (n), add the organic polyamine (II) to the urethane compound (I[[) and prepare 1! When the polyamine (n) is solid at room temperature, it is heated to the melting point of the organic polyamine itself to dissolve it.

In this case, the urethane compound <m> acts as a solvent,
In particular, it is preferable to use the organic polyamine (n) in a liquid form, which has a great effect on improving safety and workability.

Urethane compound (III) is a urethane prepolymer
(1) or in addition to organic polyamine (II). The blending ratio of urethane prepolymer (1) and organic polyamine (n) is NH! /NGO~0.85~
0.95 (equivalent ratio) (When using a short chain polyol together with an organic polyamine, NH, +OH/NGO = 0.95 (equivalent ratio).
85 to 0.95 (equivalent ratio)), and a thermosetting polyurethane elastomer composition is prepared, for example, in the following manner. The temperature of the urethane prepolymer is adjusted to 60-9 (l) and degassed under vacuum (3 mHg) for about 15-30 minutes.

On the other hand, the organic polyamine (II), or the organic polyamine (II) containing a short chain polyol if necessary, or the urethane compound (I[I) added in advance to these, is heated to the liquid state (in the case of solid, it is heated to the melting point). and liquefy). As mentioned above, the temperature of the vacuum degassed urethane prepolymer (1) is adjusted to 60 to 90°C, and the organic polyamine (II) or short chain polyol-containing organic polyamine is mixed to prevent entrained bubbles during mixing. After completely defoaming, pour into a mold, preferably at 5-130°C, especially at 90-125°C.
A urethane elastomer is obtained by aging for 1 to 24 hours.

In order to facilitate these operations, the pot life of the thermosetting polyurethane elastomer composition is determined by the mixing temperature, the curing reaction retarder, or, if tolylene diisocyanate (abbreviated as TDI) is used, the 2.4-TDI content. The higher the ratio, the longer the pot life, and these operations can be used to adjust the pot life to 1 to 30 minutes, preferably 3 to 20 minutes.

Effects> The thermosetting urethane elastomer composition of the present invention uses a small variety of urethane prepolymer (I) to provide thermosetting properties of any hardness without impairing performance and with little bleeding. Since molded urethane elastomers can be obtained, they are useful for industrial products such as tires, rolls, hammers, pads, belts, and packing.

<Examples> Next, the present invention will be explained in detail using Examples, but the present invention is not limited to the Examples. "Parts" and "%" in the text are based on weight unless otherwise specified.

Example 1 NGO10H equivalent ratio of 2.0 was added to 500 g of polypropylene ether glycol with an average molecular weight of 1000 and 500 g of polypropylene ether glycol with an average molecular weight of 2000.
The isomer ratio is 2.4/2.6 = 80/20)
261g of lylene diisocyanate was added and reacted for 5 hours in a flask at 80°C in a nitrogen stream, and the viscosity at 75°C was 4.
A urethane prepolymer (I-1) having a free isocyanate equivalent of 50 cps % of 850 was obtained.

As a urethane compound (III) to be mixed with this prepolymer (1-1), propylene oxide was added to n-butanol in a conventional manner to prepare a polypropylene ether monool having a molecular weight of 1000. 200g (0.2 mol) of this polyalkylene ether monool
17.57 g (0,101 mol) of tolylene diisocyanate with an isomer ratio of 2.4/2.6 = 80720 was added to the mixture, and after reacting for 5 hours in a flask at 80°C in a nitrogen stream, the remaining free Add enough methyl alcohol to block inocyanate groups, and have a urethane bond in the molecule that has neither free isocyanate groups nor hydroxyl groups 25
Urethane compound (I[[-
1) was obtained.

The method for producing and evaluating the urethane elastomer includes adding the urethane compound (I[[-1) to the urethane prepolymer (1-1) or the urethane prepolymer (1-1).
The mixture was heated to 80°C in a flask, MOCA pre-melted at 110°C in a separate container was added, and the mixture was quickly stirred and mixed while degassing under vacuum.
It is cast into a mold capable of producing a sheet with a thickness of 2 to 3 nm. After casting, the sheet was heat cured at 110° C. for about 15 hours, and then released from the mold, and the physical properties of the prepared sheet were evaluated using the vulcanized rubber physical testing method (JIS K 6301).

The following Table 1 shows the compounding conditions during the production of the urethane elastomer, the presence or absence of bleed of the elastomer, and the physical properties of the obtained urethane elastomer.

Example 2 1000 g of polycaprolactone polyol with a molecular weight of 1300 obtained by addition polymerizing ε-caprolactone using ethylene glycol as an initiator was added with an isomer ratio of 2.4/2.6 = 80/20 so that the NGO10H equivalent ratio was 2.0. Add 267 g of tolylene diisocyanate and
Reacted for 5 hours in a 0°C flask, viscosity L at 75°C.
A urethane prepolymer (1-2) of 100 cps and a free isocyanate equivalent of 830 was obtained. As a urethane compound to be mixed with this prepolymer (I-2),
Molecular weight 80 obtained by addition polymerization of ε-caprolactone using 2-ethylhexyl alcohol as an initiator by a conventional method.
Isomer ratio 2.4/2.6 = 80/ to 800 g of polycaprolactone monol, which is solid at room temperature of 0 and has a melting point of 37 °C.
After adding 88 g of tolylene diisocyanate of No. 20 and reacting for 5 hours in a flask at 80°C in a nitrogen stream, enough methyl alcohol was added to block the remaining free isocyanate groups, and both free isocyanate groups and hydroxyl groups were removed. 8 at 75°C with no urethane bonds in the molecule
00 cps of urethane compound (III-2) was obtained.

Table 2 shows the compounding conditions during the production of the urethane elastomer, the presence or absence of bleed of the elastomer, and the physical properties of the obtained urethane elastomer.

Table 3 shows, as a comparative example, the physical properties of urethane elastomers obtained by a hardness reduction method using prepolymers (I-1) and (1-2) in combination with MOCA and a short chain polyol. The tensile strength and tear strength were inferior.

As described above, it has been confirmed that the present invention reduces hardness without impairing the physical properties of thermosetting urethane elastomers and has excellent bleed resistance.

Claims (1)

[Claims] Urethane prepolymer (I), organic polyamine (II)
, which is obtained by reacting a monool with an average molecular weight of 200 to 10,000 with an organic isocyanate, and is characterized by consisting of a urethane compound (III) having 1 to 3 urethane bonds in the molecule and having no isocyanate group. A thermosetting urethane elastomer composition.