JPH11286601A - Production of self-lubricating polyurethane elastomer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a self-lubricating polyurethane elastomer which contains a high content of a lubricating oil and can give a slide seal having markedly reduced frictional resistance by reacting a polyol component with a diisocyanate component in the presence of a lubricating oil. SOLUTION: The polyol component used is exemplified by a polyester polyol, a polyether polyol, or a polycarbonate polyol each of which has a molecular weight of about 1,000-2,500. The diisocyanate used is exemplified by an alicyclic diisocyanate or an aromatic diisocyanate. The lubricating oil used is exemplified by a mineral oil (#30-400), a silicone oil (#400 or #200), a fluorine oil (#400), an ester oil (400 cSt), or a polyglycol oil (#400), has a viscosity (20 deg.C) of about 500-2,000 cSt, and is used in an amount of about 25 to 80 pts.wt. per 100 pts.wt. polyurethane elastomer to be formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a self-lubricating polyurethane elastomer. More specifically,
The present invention relates to a method for producing a self-lubricating polyurethane elastomer suitably used as a molding material for a slide seal or the like.

[0002]

2. Description of the Related Art Among various elastomers currently used, polyurethane elastomers are widely used as molding materials for sealing members such as packings and O-rings because of their excellent abrasion resistance and oil resistance.

When a polyurethane elastomer having such properties is used as a slide seal, not only the sealing properties but also the friction and wear properties of the elastomer on the slide are important factors.

Conventionally, a polyurethane elastomer molded by a compression molding method has been used as a slide seal. However, problems such as high frictional resistance and poor durability have been observed. In addition, various improvements such as adding a lubricant or a lubricating oil to a polyurethane elastomer have been attempted.

[0005] However, in such a conventional improvement method, the addition ratio of a lubricant or a lubricating oil is limited to about several percent by weight, and there are disadvantages such as complicating the manufacturing process.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a self-lubricating polyurethane elastomer which can be added with a high content of lubricating oil and therefore can form a slide seal with greatly reduced frictional resistance. An object of the present invention is to provide a method which can be manufactured by a simple process.

[0007]

SUMMARY OF THE INVENTION The object of the present invention is as follows.
This is achieved by reacting a polyol component and a diisocyanate component in the presence of a lubricant to produce a self-lubricating polyurethane elastomer.

[0008]

DETAILED DESCRIPTION OF THE INVENTION The polyurethane-forming reaction in the presence of a lubricant, preferably a polyurethane-forming reaction using a chain extender, and the subsequent molding can be carried out, for example, as follows. (1) After a catalyst and a chain extender are previously mixed with the polyol component, a diisocyanate and a lubricating oil are added and reacted. Inject it into the mold as it is, cure it for about 15-30 minutes at about 80-120 ° C, take it out of the mold, pulverize it as it is or harden it, and heat and melt it using an injection molding machine, then mold In the state of being re-formed in the mold, it is heated at a temperature of about 80 to 120 ° C. for about 15 to 48 hours. (2) After preliminarily mixing a catalyst with the polyol component, excess diisocyanate and lubricating oil are added and reacted. About 10
After reacting at 0 to 120 ° C. for about 30 to 45 minutes, a chain extender is added to the liquid prepolymer containing free diisocyanate and poured into a mold, and the product in its original shape or cured is pulverized, After being heated and melted using an injection molding machine, it is heated at a temperature of about 80 to 120 ° C. for about 15 to 48 hours in a state of being remolded in a mold. (3) The polyol component, catalyst, chain extender, lubricant and diisocyanate are mixed and reacted. In this case, the diisocyanate is reacted with an equivalent less than the number of functional groups possessed by the polyol component and the chain extender. The resulting reaction product can be stored and roll processed and can be crosslinked at a later stage by mixing with the same or another diisocyanate. As the diisocyanate, when 4,4′-diphenylmethane diisocyanate is used, or when an unsaturated chain extender such as 1,6-hexanediol diacrylate, pentaerythritol triacetate, glycerin monoallyl ether, or allyl methacrylate is used, It can be crosslinked by peroxide or sulfur.

As the polyol component, polyester polyols, polyether polyols, polycarbonate polyols and the like each having a molecular weight of about 1000 to 2500 are used. Polyester polyols include well-known condensation reaction products of dicarboxylic acids and polyols, polycaprolactone polyols, and the like.Polyether polyols include, for example, polytetramethylene glycol, and polycarbonate polyols include, for example, poly Hexamethylene carbonate ether,
Polytetramethylene carbonate ether or the like is used.

From the viewpoint of various mechanical properties, diisocyanate as another reaction component includes isophorone diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated 4,4'-
Alicyclic diisocyanate such as diphenylmethane diisocyanate or trizine diisocyanate, 4,4'-
Aromatic diisocyanates such as diphenylmethane diisocyanate, p-phenylene diisocyanate, and 1,5-naphthylene diisocyanate are used.

During the reaction between the two, a chain extender is preferably used as the third component. As chain extenders, 1,
Low-molecular-weight aliphatic diols such as 4-butanediol, 1,6-hexanediol, and 2,3-butanediol, p-phenylene (β-hydroxyethyl ether) and p-xylylene glycol used in combination therewith , Aromatic or alicyclic diols such as cyclohexanediol, aromatic diamines such as 3,3'-dichloro-4,4'-diaminodiphenylmethane, further glycerin, trimethylolpropane,
Low molecular weight aliphatic triols such as trimethylolethane are used.

As the catalyst, 1,4-diaza [2,2,2]
Bicyclooctane, dibutyltin diureate and the like are used in an amount of about 0.01 to 0.5 part by weight per 100 parts by weight of the total amount of the urethanizing reaction raw material.

Lubricants include mineral oil (# 30-400), silicone oil (# 400, # 200), fluorine oil (# 400), ester oil
(400 cst), polyglycol oil (# 400), etc., having a viscosity (20 ° C.) of about 500 to 2000 cst, preferably about 800 to 1200 cst.
Are used in a proportion of about 25 to 80 parts by weight, preferably about 50 to 70 parts by weight, per 100 parts by weight of the polyurethane elastomer formed. If a lubricating oil with a lower viscosity than this is used, the lubricating oil will easily come off from the oil-containing polyurethane material,
On the other hand, when a lubricating oil having a higher viscosity is used, it becomes difficult to uniformly disperse the lubricating oil. If the proportion is lower than this, the self-lubricating property aimed at by the present invention cannot be obtained. On the other hand, if the proportion is higher than this, molding of the polyurethane elastomer becomes difficult.

In the molding of a slide seal using such a self-lubricating polyurethane elastomer, a reaction mixture used for a urethanization reaction is molded in a molding die in which a slide seal reinforcement to which an adhesive has been applied is housed in advance. This is performed by injecting pressure into the inside and causing a heat curing reaction.

[0015]

The self-lubricating polyurethane elastomer according to the present invention contains a high content of lubricating oil in a finely dispersed state. Greatly improve the characteristics. However, although the physical properties of the rubber are slightly reduced by the addition of the lubricating oil, there is no problem in slide seal applications.

[0016]

Next, the present invention will be described by way of examples.

Example 2 Two-component mixed type polyurethane material A liquid (polyol component) 90 g
After degassing under reduced pressure, a 1,4-diaza [2,2,2] bicyclooctane-dipropylene glycol (1: 2 weight ratio) mixed catalyst
Add 0.27 g, and add two-component mixed polyurethane material B
90 g of the (diisocyanate component) and 120 g of lubricating oil (TONNA OIL S, Showa Shell Sekiyu KK) were added, stirred for 1.5 minutes, and defoamed under reduced pressure.

This mixed solution was poured into a molding die of about 50 ° C., formed into a sheet (150 × 150 × 2 mm), and then cured at about 80 ° C. at ambient temperature (temperature in a constant temperature bath) for about 20 minutes. . The obtained oil-containing polyurethane sheet (lubricating oil content: 40% by weight) was released from the mold, and then subjected to secondary vulcanization in an oven at 80 ° C. for 24 hours.

The following items were measured for the obtained secondary vulcanized sheet.

Comparative Example 1 In the example, no lubricating oil was used.

Comparative Example 2 Measurements on a compression molded polyurethane sheet were performed in the same manner as in the example.

The results obtained are shown in the following table. tableTest items Example Comparative Example 1 Comparative Example 2  [Physical property test] Hardness (JIS A) 72 90 72 100% stress (Kgf / cm²) 37 99 31 Tensile strength (Kgf / cm²) 70 140 181 Elongation (%) 220 168 374 Tear strength (Kgf / cm) 23 60 49 [Friction wear test] Static friction coefficient (-) 0.47 1.09 1.32 Dynamic friction coefficient (-) 0.40 2.70 2.67 Wear weight (mg) 6.7 5.6 6.4 Heating temperature of sliding (℃) 37.0 95.0 140.0

[Procedure amendment]

[Submission date] July 24, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction contents]

[0008]

DETAILED DESCRIPTION OF THE INVENTION The polyurethane-forming reaction in the presence of a lubricant, preferably a polyurethane-forming reaction using a chain extender, and the subsequent molding can be carried out, for example, as follows. (1) After a catalyst and a chain extender are previously mixed with the polyol component, a diisocyanate and a lubricating oil are added and reacted. Inject it into the mold as it is, cure it for about 15-30 minutes at about 80-120 ° C, take it out of the mold, pulverize it as it is or harden it, and heat and melt it using an injection molding machine, then mold In the state of being re-formed in the mold, it is heated at a temperature of about 80 to 120 ° C. for about 15 to 48 hours. (2) After preliminarily mixing a catalyst with the polyol component, excess diisocyanate and lubricating oil are added and reacted. About 10
After reacting at 0 to 120 ° C. for about 30 to 45 minutes, a chain extender is added to the liquid prepolymer containing free diisocyanate and poured into a mold, and the product in its original shape or cured is pulverized, After being heated and melted using an injection molding machine, it is heated at a temperature of about 80 to 120 ° C. for about 15 to 48 hours in a state of being remolded in a mold. (3) The polyol component, catalyst, chain extender, lubricant and diisocyanate are mixed and reacted. In this case, the diisocyanate is reacted with an equivalent less than the number of functional groups possessed by the polyol component and the chain extender. The resulting reaction product can be stored and roll processed and can be crosslinked at a later stage by mixing with the same or another diisocyanate. When 4,4′-diphenylmethane diisocyanate is used as the diisocyanate, or when an unsaturated chain extender such as 1,6-hexanediol diacrylate, pentaerythritol triacrylate , glycerin monoallyl ether, or allyl methacrylate is used. , And can be cross-linked by peroxide or sulfur.

Claims (2)

[Claims] 1. A method for producing a self-lubricating polyurethane elastomer, comprising reacting a polyol component and a diisocyanate component in the presence of a lubricating oil. 2. A slide seal formed from the self-lubricating polyurethane elastomer according to claim 1.