JPH0543645A - Oil-resistant belt - Google Patents

Abstract

PURPOSE:To provide a belt excellent in resistance to heat and oil by producing it from a polyurethane elastomer compsn. mainly comprising p-phenylene diisocyanate, 4,4'-methylenebis(o-chloroaniline), and a specific polyol. CONSTITUTION:An oil-resistant belt is produced from a polyurethane elastomer compsn. mainly comprising p-phenylene diisocyanate, 4,4'-methylenebis(o- chloroaniline), and a hydroxyl-terminated polyester polyol having groups of formula I and/or formula II and a number-average mol.wt. of 1,600-3,500.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt having excellent oil resistance, and more particularly to an oil resistant belt formed of a polyurethane elastomer composition.

[0002]

2. Description of the Related Art Belts of various types such as flat belts, round belts and toothed belts are used as constituent members of machine tools and the like. Conventionally, polyurethane elastomer compositions have been used as materials for the various belts. This polyurethane elastomer composition is classified into an ether type and an ester type.

The former ether type is currently most commonly used as adiprene (Uniroy).
2,4-typically represented by al Chemical Co., Ltd.
Tolylene diisocyanate or a mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate [= TDI, hereinafter simply abbreviated as TDI]
And polytetramethylene ether glycol [= PTM
G, hereinafter abbreviated as PTMG as appropriate], 4,4'-methylenebis (O-
Chloroaniline) [= MBOCA, hereinafter simply MBO
Abbreviated as CA], a belt formed by curing with a curing agent of an aromatic diamine such as 2,6-dichloro-P-phenylenediamine and 1,2-bis (2-aminophenylthio) ethane (so-called adiprene. What is called a type]. This belt is excellent in various characteristics such as mechanical characteristics.

By the way, due to recent rapid technological innovation, the required characteristics of various belts have been further enhanced. For example, the timing belt for driving the back spindle used in a machine tool such as an NC lathe is subjected to heat of 60 ° C to 80 ° C in a mist-like oil atmosphere, which causes high temperature / oil environment in such a machine tool. There is a need for something applicable to use in.

However, the so-called adiprene type belt cannot satisfy the required characteristics in heat resistance, and further,
A belt molded from an ether-based polyurethane elastomer composition is essentially swelled and thermally deteriorated in an oil environment. Therefore, as a means for improving the heat resistance of this belt, it is possible to manufacture it by using para-phenylene diisocyanate [= PPDI, which will be simply abbreviated as PPDI hereinafter], which can be considered to obtain higher heat resistance due to the molecular structure of polyisocyanate. In consideration of the possibility that PPDI has a fast reaction, 1,4-butanediol [= 1,4-BG] and 1,4 bis (2-hydroxyethoxy) benzene [= BHEB] are used as curing agents. It is known that diol compounds are effective [(Urethane
chemistry and Application ACSSymposium Series
), 172, 419-431, 1981, University of Detroit].

However, when the above diol-based curing agent is used for PPDI, the mold releasing time is long and there is a problem in productivity, and further heat resistance, oil resistance and other mechanical properties are not satisfactory. It was Furthermore, PPD
As a curing agent for I, it was sought to apply a diamine-based compound instead of the diol-based compound, and among these diamine-based compounds, 4,4′-methylenebis (dichloroaniline) [= TCDMA, hereinafter simply referred to as TCDA
The production method using M] is proposed (JP-A-63-270723). However, the above curing agent TC was added to PPDI.
When DAM is used, it is possible to obtain heat resistance that is to some extent satisfactory, but there is a problem in productivity due to the high melting point of TCCAM.

In order to eliminate the above-mentioned problems, it has been proposed to obtain a polyurethane elastomer composition by using a curing agent MBOCA in a urethane prepolymer composed of PPDI and a specific ether-based polyol (Japanese Patent Application No. 2000-242242). Flat 3-21107). The proposed polyurethane elastomer composition has excellent heat resistance and can be precisely molded, and has a very excellent reaction property with a proper reaction time.

On the other hand, in spite of such excellent characteristics, the belt molded from the ether-based polyurethane elastomer composition has a drawback that it is easily swelled in an oil environment due to its essential property, and therefore, it is not used for certain applications. It may be difficult. That is, the belt molded from the ether-based polyurethane elastomer composition may have some problems in oil resistance.

On the other hand, it can be generally said that ester polyurethane elastomers have excellent oil resistance. This ester-based polyurethane elastomer composition has hitherto been used as polyisocyanate as TDI.
There was a belt molded using MBOCA as a curing agent. However, while this one has excellent oil resistance,
In terms of heat resistance, there has been a problem that the recently required performance cannot be satisfied.

Therefore, an attempt was made to use PPDI instead of TDI as the polyisocyanate.
Since this PPDI has a fast reaction as described above, it is very difficult to mold it, and it cannot be cast and cannot be molded into a belt.

[0011]

Therefore, according to the present invention,
An object of the present invention is to propose a belt having heat resistance equivalent to that of a conventional belt and excellent in oil resistance.

[0012]

Means for Solving the Problems As a result of intensive studies conducted by the present inventors in view of the above situation, the inventors have found that the above technical problems can be solved by adopting the following technical means to complete the present invention. Came to. That is, the oil resistant belt of the present invention contains para-phenylene diisocyanate, a hydroxyl group-terminated polyester polyol, and 4,4′-methylenebis (O-chloroaniline) as main components, and the hydroxyl group-terminated polyester polyol is Of at least one of the polyol having a group represented by the formula [1] and the polyol having a group represented by the formula [2], and the number average molecular weight of the polyol is 1 , 600 or more and 3,500 or less.

PPDI was selected as the isocyanate because the TDI represented by the conventional so-called adiprene type was used.
This is because it is considered that a belt having higher heat resistance than that of the polyurethane elastomer using is obtained. It was TCD that decided to use MBOCA as a curing agent.
It is relatively cheaper than AM, and its melting point is slightly lower (TCMAM melting point is 155 to 170 ° C, MBOCA melting point is 98 ° C or higher), and it has the advantage of being easy to handle, suitable for manufacturing, and having good workability. Because there is.

The hydroxyl group-terminated polyester polyol contains at least one of a polyol having a group represented by the formula [Chemical formula 1] and a polyol having a group represented by the formula [Chemical formula 2]. It was decided that these polyols had a low reactivity with the terminal diol, and the pot life (from adding the curing agent to the urethane prepolymer with fluidity until the viscosity increased and casting work became impossible) This is because the time can be set longer than when using a general-purpose polyester polyol.

The pot life is very important in the production process of polyurethane, and if the reaction in the curing step of the urethane prepolymer is too fast or too slow, there is a problem in terms of workability and productivity. That is, a pot life of about 2 to 20 minutes is suitable, and it is preferable that the pot life is as short as possible within an appropriate range. However, if it is too short, work such as mixing and casting becomes difficult and workability deteriorates,
On the other hand, if it becomes too long, productivity will deteriorate.

A hydroxyl group-terminated polyester polyol containing at least one of a polyol having a group represented by the formula [1] and a polyol having a group represented by the formula [2]. The reason why the number average molecular weight is 1,600 or more and 3,500 or less is that when it is less than 1,600, the pot life is very short and molding is practically impossible, Three
When it is more than 500, the viscosity of the obtained prepolymer is high, so that the mixing is not sufficiently performed during the addition and stirring of the curing agent, and the physical properties are likely to vary, and the molecular weight of the polyol is large. This is because the content of the soft segment, which is a component, increases, but the content of the hard segment decreases, and therefore the crosslink density decreases, so that the mechanical properties cannot satisfy the required properties.

The polyol having a group represented by the formula [Chemical formula 1] and the polyol having a group represented by the formula [Chemical formula 2] may contain either one, of course. You may contain both. The oil resistant belt of the present invention has the above composition as a main component, and even if other components are contained within a range not impairing the object of the present invention, they are included in the gist of the present invention. That is, the hydroxyl group-terminated polyester polyol is one or more selected from the group consisting of ethylene glycol, diethylene glycol, propylene glycol, 1,4 butanediol, neopentyl glycol and 1,6 hexane glycol. A polyester polyol or a carboxylic acid or a caprolactone polyol may be contained. Other polyester polyols such as those mentioned above may be included.

Further, the oil resistant belt of the present invention may contain additives and the like. Additives that can be used in the present invention are plasticizers, flame retardants, fillers, stabilizers, colorants and the like. Examples of the plasticizer include dioctyl phthalate (D
OP), dibutyl phthalate (DBP), dioctyl adipate (DOA), tricresyl phosphate (TCP), chlorinated paraffin, etc. can be used.

Examples of the flame retardant include phosphoric acid esters such as tris- (β-chloropropyl phosphate, tris-dichloropropyl phosphate and trischloroethyl phosphate, and bromine compounds such as dibromoneopentyl glycol and tribromoneopentyl alcohol. Fillers such as glass fiber, carbon black,
Calcium carbonate, talc, kaolin, zeolite, diatomaceous earth, perlite, permiculite, titanium dioxide, etc. can be used.

As the stabilizer, conventionally used antioxidants, ultraviolet absorbers, light stabilizers, hydrolysis inhibitors and the like can be used. Antioxidants are radical chain inhibitors
The former includes phenols and aromatic amines that act as peroxide decomposers and have steric hindrance. As a radical chain inhibitor, butylated hydroxytoluene, tetrakis [methylene ・ 3 ・ (3 '・ 5'-di ・ t-butyl-
4-hydroxyphenyl) propionate] methane, n.
Octadecyl-β- (4 '・ hydroxy-3'-5' ・
Di ・ t-butylphenyl) propionate, 1,3,5 tris (4 ・ t-butyl ・ 3hydroxy ・ 2,6-dimethylbenzyl) isocyanuric acid, triethylene glycol bis 3 (2-t-butyl ・ 4hydroxy-5 ・ methylphenyl)
Propionate or the like can be used.

As the peroxide decomposing agent, 4,4'thiobis (6-t-butyl.m.cresol, dilauryl.thiodipropionate, distearylthio.dipropionate, thiophenylphosphite and the like can be used. As a UV absorber, salicylic acid-based phenyl salicylate, Pt-butylphenyl salicylate, benzophenone-based 2,4-di-hydroxybenzophenone, 2-
Hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, benzotriazole-based 2 (2'-hydroxy-5'-methylphenyl) benzotriazole, 2 (2'-hydroxy-
3'-t-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2 (2'-hydroxy-3 ',
5'-di-t-aminophenyl) benzotriazole,
Siare acrylate type ethyl-2-cyano-3,5-
Diphenyl acrylate, 2 (2'-hydroxy-5 '
-T-octylphenyl) benzotriazole and the like can be used.

As the UV screen, pigments such as carbon black and zinc white can be used. As a light stabilizer, there is a hindered amine. Hindered amines include bis (1,2,2,2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butylmalonate
6,6-pentamethyl-4-piperidyl, dimethyl-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate of succinate,
Poly [[6- (1,1,3,3-tetramethylbutyl)
Imino-1,3,5-triazine-2,4-diyl]
[(2,2,6,6-tetramethyl-4-piperidyl)
Imino] hexamethylene [[2,2,6,6-tetramethyl-4-piperidyl) imino]], 2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butylmalon Acid bis (1,2,2,6,6-pentamethyl-4-piperidyl) or the like can be used.

As a hydrolysis inhibitor, carbodiimide type stavaxol-1, PCD (Bayer Co.), hexamethylenetetraamine, azodicarbonamide, 4-t
-Butylcatechol and the like can be used. The method for producing the urethane prepolymer by reacting the hydroxyl group-terminated polyester polyol and paraphenylene diisocyanate is not particularly limited, for example, a known method including reaction temperature, reaction time, presence or absence of a solvent, etc. You can also do it in.

It is necessary to react the organic polyisocyanate and the active hydrogen-containing compound so that the prepolymer thus obtained has an isocyanate group content of 1 to 20% by weight. When the isocyanate group content of the obtained prepolymer exceeds 20% by weight and becomes large, the amount of free paraphenylene diisocyanate increases and the storage stability of the urethane prepolymer becomes poor.

On the other hand, if it is less than 1% by weight, the urethane prepolymer has a low isocyanate group content and the pot life becomes too long, resulting in poor productivity.

[0026]

EXAMPLES The oil resistant belt of the present invention will be described in more detail with reference to examples. The following examples and the like were performed by the following procedure. 100 parts by weight of the polyol component (hereinafter, shown in (1)) is added to the polyisocyanate component (hereinafter,
(Shown in (2)) is added and reacted at 85 ° C. for 1 hour under a nitrogen stream to obtain a urethane prepolymer having a terminal isocyanate group.

The viscosity of the obtained urethane prepolymer at 80 ° C. was measured by Haake rotational viscosity / Rotovisco RV-12.
Was used (the results are shown in Table 1). 100 parts by weight of the urethane prepolymer obtained as described above was kept at 80 ° C., a curing agent (hereinafter referred to as (3)) was melted at 120 ° C., mixed and kept at 110 ° C. in advance. After being poured into a belt mold and heated for 2 hours, it was taken out of the mold and then secondarily cured with heated air at 110 ° C. for 10 hours to obtain a toothed belt 1 whose cross section is shown in FIG. At this time, the pot life was measured (the results are shown in Table 1). According to the procedure described above, examples and comparative examples were carried out using the components specifically shown below. (Example 1) (1) Polyol component 70 parts by weight of a polyester polyol (Kuraray Co., Ltd., trade name CLAPOL L-2010) having an average molecular weight (which refers to the number average molecular weight Mn. The same applies hereinafter) and an average molecular weight Of 2,015 polyester polyol (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name Nipporan 407
0) 30 parts by weight were blended and used.

In this specification, trade name CLAPOL L-***
What is shown as * and P-*** (in this example, Clapol L-2010) is shown by the following chemical formulas 3 and 4, respectively, and is 3-methyl-1,5-
It is a copolymer of pentanediol and β-methyl-δ-valerolactone.

[0029]

[Chemical 3]

[0030]

[Chemical 4]

(2) Polyisocyanate Component Paraphenylene diisocyanate [= PPDI, manufactured by DuPont, the same applies hereinafter] was used in an amount of 15.5 parts by weight. (3) Hardener 4,4'-methylenebis (O-chloroaniline) [= M
10.3 parts by weight of BOCA, manufactured by Ihara Chemical Industry Co., Ltd., Ihara Cumian MT, the same shall apply hereinafter].

The pot life was 2 minutes and 30 seconds. A toothed belt 1 was obtained with the above composition. The polyester polyols shown under the trade names of Clapol L-*** and P-**** in this specification are liquid at room temperature, so compared to general-purpose polyester polyols that are solid at room temperature, It has the advantage of very good workability. (Example 2) (1) Polyol component Polyester polyol having an average molecular weight of 2,059 (Kuraray Co., Ltd., trade name CLAPOL L-2010) 90
Part by weight and 10 parts by weight of a polyester polyol having an average molecular weight of 2,011 (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name Nipporan 4040) were blended and used. (2) Polyisocyanate component PPDI was used in an amount of 15.9 parts by weight. (3) Hardener MBOCA was used in an amount of 9.9 parts by weight.

The pot life was 2 minutes and 25 seconds. A toothed belt 1 was obtained with the above composition. (Example 3) (1) Polyol component Polyester polyol having an average molecular weight of 2,022 (Kuraray Co., Ltd., trade name CLAPOL L-2010) 90
Parts by weight and 10 parts by weight of a polyester polyol having an average molecular weight of 1,986 (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name Nipporan 4042) were blended and used. (2) Polyisocyanate component PPDI was used in an amount of 15.9 parts by weight. (3) 10.1 parts by weight of the curing agent MBOCA was used.

The pot life was 2 minutes and 25 seconds. A toothed belt 1 was obtained with the above composition. (Example 4) (1) Polyol component Polyester polyol having an average molecular weight of 2,022 (Kuraray Co., Ltd., trade name CLAPOL L-2010) 90
Part by weight and 10 parts by weight of a polyester polyol having an average molecular weight of 2,055 (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name Nipporan 4010) were blended and used. (2) Polyisocyanate component PPDI was used in an amount of 15.8 parts by weight. (3) Hardener MBOCA was used in an amount of 9.9 parts by weight.

The pot life was 2 minutes and 05 seconds. A toothed belt 1 was obtained with the above composition. (Example 5) (1) Polyol component Polyester polyol having an average molecular weight of 2,022 (Kuraray Co., Ltd., trade name CLAPOL L-2010) 10
0 parts by weight was used. (2) Polyisocyanate component PPDI was used in an amount of 15.8 parts by weight. (3) 10.8 parts by weight of the curing agent MBOCA was used.

The pot life was 4 minutes and 05 seconds. A toothed belt 1 was obtained with the above composition. (Example 6) (1) Polyol component Polyester polyol having an average molecular weight of 1,929 (Kuraray Co., Ltd., trade name CLAPOL L-2010) was used.
100 parts by weight was used. (2) Polyisocyanate component PPDI was used in an amount of 16.6 parts by weight. (3) 10.7 parts by weight of the curing agent MBOCA was used.

The pot life was 5 minutes 05 seconds. A toothed belt 1 was obtained with the above composition. Next, a comparative example to the above embodiment will be described. (Comparative Example 1) (1) Polyol Component Polyester polyol having an average molecular weight of 1,042 (Kuraray Co., Ltd., trade name CLAPOL L-1010) was used.
100 parts by weight was used. (2) Polyisocyanate component PPDI was used in an amount of 30.7 parts by weight. (3) 17.4 parts by weight of the curing agent MBOCA was used.

The pot life was 1 minute and 10 seconds. As mentioned above, the pot life was too short as 1 minute and 10 seconds to cast, and a toothed belt could not be obtained. (Comparative Example 2) (1) Polyol component Polyester polyol having an average molecular weight of 1,509 (Kuraray Co., Ltd., trade name CLAPOL P-1510) was used.
100 parts by weight was used. (2) Polyisocyanate component PPDI was used in an amount of 21.2 parts by weight. (3) 13.6 parts by weight of curing agent MBOCA was used.

The pot life was 1 minute and 30 seconds. As mentioned above, the pot life was too short as 1 minute and 30 seconds to cast, and a toothed belt could not be obtained. (Comparative Example 3) (1) Polyol component Polyester polyol having an average molecular weight of 3,728 (Kuraray Co., Ltd., trade name CLAPOL L-3010) was used.
100 parts by weight was used. (2) Polyisocyanate component PPDI was used in an amount of 8.6 parts by weight. (3) 5.5 parts by weight of the curing agent MBOCA was used.

The pot life was 10 minutes and 25 seconds. Although the toothed belt 1 was obtained with the above composition, there was a problem in moldability as described later in the evaluation test. (Comparative Example 5) (1) Polyol component Polyester polyol having an average molecular weight of 2,055 (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name Nipporan 40
10) was used in 100 parts by weight. (2) Polyisocyanate component PPDI was used in an amount of 15.6 parts by weight. (3) Curing agent MBOCA was used in an amount of 10.5 parts by weight.

The pot life was 0 minutes and 40 seconds. As mentioned above, the pot life was too short as 0 minutes and 40 seconds to cast, and a toothed belt could not be obtained. (Comparative Example 6) (1) Polyol component Polyester polyol having an average molecular weight of 1,986 (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name Nipporan 40
42) was used in 100 parts by weight. (2) Polyisocyanate component 16.1 parts by weight of PPDI was used. (3) 9.8 parts by weight of curing agent MBOCA was used.

The pot life was 0 minutes and 50 seconds. As mentioned above, the pot life was too short as 0 minutes and 50 seconds to cast, and a toothed belt could not be obtained. (Comparative Example 7) (1) Polyol component Polyester polyol having an average molecular weight of 2,051 (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name Nipporan 40
73) was used in 100 parts by weight. (2) Polyisocyanate component PPDI was used in an amount of 15.6 parts by weight. (3) 10.1 parts by weight of the curing agent MBOCA was used.

The pot life was 1 minute and 25 seconds. As mentioned above, the pot life was too short as 1 minute and 25 seconds to cast, and a toothed belt could not be obtained. (Comparative Example 8) (1) Polyol component Polyester polyol having an average molecular weight of 2,015 (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name Nipporan 40
70) was used in 100 parts by weight. (2) Polyisocyanate component PPDI was used in an amount of 15.9 parts by weight. (3) Curing agent MBOCA was used in an amount of 10.6 parts by weight.

The pot life was 1 minute and 15 seconds. As mentioned above, the pot life was too short as 1 minute and 15 seconds to cast, and a toothed belt could not be obtained. (Comparative Example 9) (1) Polyol component Polycaprolactone polyol having an average molecular weight of 1,996 (trade name: Praxel 2 manufactured by Daicel Chemical Industries, Ltd.)
20 N) was used in 100 parts by weight. (2) Polyisocyanate component 16.0 parts by weight of PPDI was used. (3) Hardener MBOCA was used in an amount of 9.9 parts by weight.

The pot life was 0 minutes and 50 seconds. As mentioned above, the pot life was too short as 0 minutes and 50 seconds to cast, and a toothed belt could not be obtained. (Comparative Example 10) (1) Polyol component Polytetramethylene glycol having an average molecular weight of 1,986 (trade name PTG200, manufactured by Hodogaya Chemical Co., Ltd.)
0) was used in 100 parts by weight. (2) Polyisocyanate component 16.1 parts by weight of PPDI was used. (3) Hardener 4,4'-methylenebis (dichloroaniline) [TCD
AM, manufactured by Ihara Chemical Industry Co., Ltd., trade name TCDA
M] was used in an amount of 9.8 parts by weight.

The pot life was 14 minutes and 30 seconds. A toothed belt 1 was obtained with the above composition. The polyol component used in this comparative example is an ether type which is currently widely used. (Comparative Example 11) (1) Prepolymer Trade name Hyprene L-80 (manufactured by Mitsui Toatsu Co., Ltd.) was used. The polyisocyanate component is TDI and the polyol component is ether type. (2) 7.8 parts by weight of the curing agent MBOCA was used.

The pot life was 15 minutes and 36 seconds. A toothed belt 1 was obtained with the above composition. The polyisocyanate component used in this comparative example is TDI which is currently widely used. Examples 1 to 6 and Comparative Examples 3 and 1
The toothed belt 1 obtained in Nos. 0 and 11 was used as a sample for various tests described below. [Evaluation test] For each of the samples, the oil resistance is as follows,
Also, an evaluation test of running property under a constant load was performed. Oil Resistance Evaluation The obtained toothed belt 1 was evaluated by the swelling ratio of the tooth portion after being immersed in oil for a certain period of time.

Each sample was treated with a metalworking oil, Yukawa Cut N-
100 (made by Yukawa Processing Oil Co., Ltd.) at room temperature 1
Soaked for a week. Then, the swelling ratio with oil was determined by measuring and calculating the rate of change of the height H of the tooth portion 2 of each toothed belt 1 of the sample. The results are shown in the table below.

[0049]

[Table 1]

The samples of Comparative Examples 10 and 11 (toothed belts molded with an ether type polyurethane elastomer composition) have a swelling ratio of about 3%, while those of the Examples are 1.5% or less, respectively. There was only swelling rate. That is, the belt according to this example has an excellent property that it is extremely difficult to swell even in an oil atmosphere. Travelability Evaluation A travel test was conducted using a sample that had been subjected to the oil resistance test.

This running test was carried out by using each toothed belt 1 of the sample.
(Tooth profile dimension as shown in FIG. 1: tooth pitch (P) 5 mm,
The number of teeth was 163, the length was 815 mm, and the width was 15 mm. The driving pulley and the driven pulley (each having 30 teeth) were stretched and run at room temperature at 2,200 rpm. At this time, the blades were fixed to the driven pulley to apply a load of 0.42 Kgfm.

By the way, Comparative Examples 10 and 11 which are samples molded from an ether type polyurethane elastomer composition.
When it was attempted to run by stretching it between both pulleys, the running test could not be performed because the swelling of the sample was severe and the meshing failure occurred, as is clear from the results of the oil resistance evaluation. It was (When the swelling ratio of the tooth portion is 2% or more, poor meshing occurs, and it is practically impossible to run). Therefore, a running test was performed only on the samples of the examples.

Samples of the Examples that have undergone this oil resistance test
Are completely abnormal after running for 1,000 hours each
Was not observed, and the running test could be continued.
Next, when the toothed belt 1 of each Example and Comparative Example is molded
The moldability of is explained. Belt formability evaluation The pot lives of Examples 1 to 6 are as shown in Table 1.
2 minutes and 30 seconds, 2 minutes and 25 seconds, 2 minutes and 25 seconds, and 2 minutes and 05 seconds
Seconds, 4 minutes 05 seconds, 5 minutes 05 seconds, generally 2 to 6 minutes
Since it is within the range where molding is possible enough, its melt viscosity
Is an appropriate range of 2,710 to 5,070.

On the other hand, the melt viscosity of Comparative Examples 1 and 2 having a number average molecular weight of less than 1,600 is 1,610,
It's a little lower at 2,210, and the pot life is 10 for 1 minute.
The casting time is very short, 1 minute 30 seconds, and casting is practically impossible.
Similarly, the pot life of Comparative Example 3 having a number average molecular weight of more than 3,500 is 10 minutes 25 seconds, which is within a moldable range, but the melt viscosity is as high as 11,290, so molding into a belt is extremely difficult. difficult.

As the polyol component, the above [Chemical formula 1]
Comparative Examples 4 to 9 containing neither the polyol having a group represented by the formula (1) nor the polyol having a group represented by the formula (Formula 2) had a generally high melt viscosity and The pot life is 1 minute 32 seconds, 0 minutes 50
Seconds, 0 minutes 40 seconds, 0 minutes 50 seconds, 1 minute 25 seconds, 1 minute 15
Since it was as short as 0 seconds and 0 minutes and 50 seconds, it was impossible to cast.

The pot lives of Comparative Example 10 using a general-purpose polyether polyol and those of Comparative Example 11 using TDI as the polyisocyanate were 14 minutes 30 seconds and 15 minutes 36 seconds, respectively, and their melt viscosities were Is about 2,500, which is a possible range for molding. Further, the toothed belt 1 as shown in FIG. 2 (a canvas (not shown) may be provided on the back surface) can be molded by replacing the mold in the same manner as described above. A method for manufacturing the toothed belt 1 will be described in detail.

A nylon cloth laminated on one side with a polyethylene resin is wound so that the polyethylene resin layer is in contact with the toothed cylindrical mold, and a tensile member 3 of "Kevlar" (aramid fiber manufactured by DuPont) is wound on the mold. Is spirally wound and put in a mold, a urethane prepolymer and a curing agent are added to the space between the mold member and the cylindrical mold, and the mixture is press-filled by a known press-fitting molding method and heated at 110 ° C for 120 minutes. Then, the tooth mold product is removed from the cylindrical mold, after which it is secondarily cured with heated air at 110 ° C. for 10 hours and cut into a belt of a predetermined width to mold the toothed belt 1.

As the canvas, for example, one made of nylon, aramid, or the like, preferably one laminated with polyethylene resin on one side is used, and the core wire is made of, for example, glass fiber, aramid fiber, steel fiber or the like. However, other ones can of course be used. Furthermore, the flat belt 1 as shown in FIG.
It is also possible to mold 0. Since the oil-resistant belt of the present invention has a small swelling ratio in an oil environment as described above, when applied to a flat belt, the degree to which the belt is stretched by the influence of oil and the tension is lowered is extremely small, and accurate friction is reduced. Conduction can maintain long-term running.

Since the oil-resistant belt of the present invention has the above-mentioned excellent properties, various belts such as toothed belts, flat belts, V-belts, round belts, etc. as constituent members of automobiles, machine tools, etc. In addition, it can be suitably applied to the above-mentioned case and can be more suitably applied when there are many situations where it is exposed to an oil environment.

[0060]

The present invention takes the above technical means, and by adopting the above-mentioned respective constituents, a belt having oil resistance equivalent to that of the conventional one and excellent heat resistance is obtained. Can be provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a toothed belt during a running test.

FIG. 2 is a perspective view of a toothed belt showing an embodiment of the oil resistant belt of the present invention.

FIG. 3 is a perspective view of a flat belt showing another embodiment of the oil resistant belt of the present invention.

Claims (2)

[Claims] 1. Paraphenylene diisocyanate, a hydroxyl-terminated polyester polyol, and 4,4 ′.
-Methylenebis (O-chloroaniline) as a main component, and the hydroxyl group-terminated polyester polyol is a group represented by the following formula: And a group represented by the following formula: And at least one of the polyols having a number average molecular weight of 1,60
An oil-resistant belt formed of a polyurethane elastomer composition having a value of 0 or more and 3,500 or less. 2. The hydroxyl group-terminated polyester polyol is one selected from the group consisting of ethylene glycol, diethylene glycol, propylene glycol, 1,4 butanediol, neopentyl glycol and 1,6 hexane glycol, or The oil-resistant belt according to claim 1, which contains a polyester polyol composed of two or more kinds and a carboxylic acid, or a caprolactone polyol.