JPS6147799A - Grease for gas cock - Google Patents

Abstract

PURPOSE:Grease having improved durability, freeze resistance, and heat resistance even in screw cocks with a large stopper, obtained by blending a poly alpha- olefin base oil with a butylenic copolymer, an alkyklphneol-aldehyde resin, molybdenum disulfide, etc. CONSTITUTION:A polyalpha-olefin as a base oil is blended with (A) 2-30wt% copolymer comprising isobutylene as a main component and n-butylene, having 200-50,000cst kinetic viscosity at 40 deg.C, (B) 0.2-10wt% alkylphenol-aldehyde resin, (C) 2-20wt% molybdenum disulfide, and (D) 3-15wt% lithium soap, to give the aimed grease.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a grease for gas cocks that is applied to the sliding surface between the gas cock body and the stopper, and particularly for screw cocks with a nominal diameter of 3/4 inch or more. This invention relates to a gas cock IJ-gose with excellent cold resistance and heat resistance.

[Prior art]

Conventionally, typical gas cock greases include mineral oil-based or vegetable oil-based greases containing molybdenum disulfide, and silicone greases that have excellent cold resistance, heat resistance, and stability over time. These greases are made by adding molybdenum disulfide, oiliness improvers, antioxidants, etc. to high viscosity mineral oil, vegetable oil, or silicone oil, and then adding bentone (bentonite treated with quaternary ammonium salt) or lithium stone. Because of the thickened grease, the nominal diameter is 3/4
In the case of screw cocks larger than 1 inch, it is impossible to maintain an oil film thick enough on the sliding surface between the gas cock body and the plug to withstand the sliding distance, which increases as the plug becomes larger, and as a result, sufficient durability cannot be obtained. There was a problem.

Furthermore, mineral oil-based and vegetable oil-based greases have a problem in that they are insufficient in cold resistance and heat resistance due to the pour point and viscosity index of their base oils.

[Problem that the invention seeks to solve]

The present invention solves the problems of conventional gas cock greases and provides a gas cock grease that has excellent durability, cold resistance, and heat resistance even for screw hooks with a nominal diameter of 3/4 inch or more. purpose.

[Means for solving problems]

In order to achieve this objective, the gas cock grease of the present invention uses poly-α-olefin as a base oil, and a copolymer of isobutylene-based normand-butylene.
~30% by weight and 0 alkylphenol aldehyde resins
．． 2-10% by weight, and 2-20% by weight of molybdenum disulfide.
and 3 to 15% by weight of lithium soap.

The inventors have discovered that the grease for gas hooks has
Increases malleability, has excellent durability, and has cold resistance.
In order to obtain a product with excellent heat resistance, as a result of research into various types, polyα-
The present invention was achieved by discovering that a grease with excellent durability and other properties can be obtained by using olefin and adding an alkylphenol aldehyde resin with particularly excellent tackifying properties in addition to known solid lubricants and thickeners. did.

The structural formula of the polyα-olefin used as the base oil in the present invention is as shown below, and 1i is generally a C-C alkyl group. The viscosity of polyα-olefin varies depending on the value of y in the above structural formula, but it is particularly preferable to use 40C and 200 to 800 cst. The combination acts as a thickener and tackifier for grease, and the general formula of its structure is shown below.

0H30H30H3 The kinematic viscosity of this copolymer at 4・OC is 2000-5
Those in the range of 0000 cst are effective for the present invention,
Particularly preferred is one having a value of 5,000 to 40,000 cst.

If the kinematic viscosity is less than 2000 cst, the addition effect will not be sufficient, and if it is more than 5000, Qcst, the pour point will be high.
The heavy low-temperature torque has a negative effect on the cold resistance performance of gas cock grease. Addition ratio to grease is 2 to 3
0% by weight and particularly preferably 5 to 20% by weight.

If it is less than 2% by weight, the effect of addition is not sufficient, and if it is more than 30% by weight, it will have an adverse effect on cold resistance performance.

Alkylphenolaldehyde resin acts as a tackifier, and its structure is shown below.

R is an alkyl group of CN3. The general properties of the resin are as follows.

Softening point 110~1soc J engineering 5K2581.
(Ring and ball method) Molecular weight: approximately 1000 Benzene vapor pressure equilibrium method.

Specific gravity: approx. 1.03 Ash content: 0.3% by weight or less J.K. SK 2272 The proportion of this resin added to the grease is 0.2 to 10% by weight, particularly preferably 0.5 to 3.0% by weight. . Addition ratio is 0.2
If it is less than 10% by weight, the effect of addition is not sufficient;
Above this, the low-temperature torque and the rotational torque at room temperature will become heavier.
Molybdenum disulfide is a solid lubricant that significantly reduces wear and friction, and should be added to grease in an amount of 2 to 20% by weight.
is preferred.

Various aliphatic lithium soaps are used as the lithium soap grease that acts as a thickener, but in the present invention, unsaturated fatty acid lithium soaps, particularly lithium 12-hydroxystearate soaps are preferred, and the addition ratio to the grease is 3 to 3. 15% by weight is preferred.

The grease for gas cocks of the present invention may contain various additives as necessary in order to improve anti-oxidation properties, anti-corrosion properties, etc.

[Effect]

The gas cock grease of the present invention uses poly-α-olefin as a base oil, which has superior properties such as heat resistance stability, low-temperature fluidity, and viscosity index compared to mineral oil-based and vegetable oil-based base oils. , a copolymer of isobutylene and normal butylene, which has tackifying properties, is added, and an alkylphenol aldehyde resin with very good tackifying properties is added to supplement the tackifying properties.1 Also, a solid lubricant. Molybdenum disulfide, which is known for its excellent wear resistance and extreme pressure resistance, and lithium soap, which is known as a thickening agent, are added, so even in screw cocks with large nominal diameters, the sliding surface between the gas hook body and the stopper is strong. A thick oil film can be formed.

〔Example〕

Example 1 - 368 g of poly-α-olefin with a kinematic viscosity of +21 cst that satisfies 4 IOC, and 1 alkylphenol aldehyde resin
Add 0 g and heat, and after dissolving add 12 g as a thickener.
Lithium hydroxystearate24. ．． Add 5 g, disperse with stirring, and raise the temperature to 205-215c. Next, this was allowed to cool, and 15 g of molybdenum sulfide and 7.5 g of a benzo-triazole derivative were added as a corrosion inhibitor to 75 g of a copolymer with normal butylene mainly composed of isobutylene and having a kinematic viscosity of about 80,000 cst at 40 C at 60 to 70 C. Add, knead well and pass through a colloid mill to obtain a product.

Example 2.3 Following the same manufacturing procedure as in Example 1, each product was obtained using the following blending ratios.

Example 2 Example 3 292.5 g polyα-olefin with kinematic viscosity 4-21 cst at +OC 367, 5 g alkylphenol aldehyde tftj fat 15 12.512 Lithium hydroxystearate 35 3
2.5 Molybdenum disulfide
508O benzotriazoyl derivative
7.5 7.5 The general properties of the greases of Examples 1 to 8 above are shown in Table 1 together with the properties of a commercially available vegetable oil-based lithium soap grease containing molybdenum disulfide as a comparative example.

Table 1 Example Comparative Example Consistency (25C, 60W) 809 271 28
9250) J Engineering 5K2220 Dropping Point C195189187187 J Engineering SK2220 Copper Plate Corrosion (100C x 24H) Pass Pass Pass Pass Ae. 52120 again. The durability, cold resistance, and heat resistance of the grease of the present invention were tested in comparison with a comparative example by applying the durability test and cold/heat resistance test method of T-52120.

(a) A screw cock with a nominal diameter of 11/'2 inch was used for the durability test, and the test was continued for the grease of Example 1 until the rotational torque suddenly increased or leakage occurred.

(Up to 20,000 times) Test results can be compared to IJ-
This is shown in the figure along with the case where a The greases of Examples 2 and 3 were also tested and showed good durability almost the same as Example 1.

(b) A screw cock with a nominal diameter of 3 inches was used for the cold resistance test, and the gas cocks coated with grease of Examples 1 to 3 of the present invention and comparative examples were held at -20C for 24 hours, and then the rotational torque and leakage were measured. did. The test results are shown in Table 2.

Table 2 (c) For the heat resistance test, the screw cock with a nominal diameter of 3/4 inch used in the cold resistance test was used as is, and after holding the gas cock coated with grease at 1200°C for 24 hours, it was taken out and returned to room temperature. Post-tested. The test results are shown in No. 81.

Table 3 [Effects] As shown in the above examples, the grease for gas cocks of the present invention has extremely superior durability in terms of durability compared to conventional products in the durability test results, and also has excellent durability at low temperatures in the cold resistance test. The rotational torque of the grease is very light, and in a heat resistance test, gas leakage occurred with conventional products, but with the present invention, no gas leakage occurred, and even when applied to screw cocks with a nominal diameter of A/4 inch or more, It turns out to be excellent.

A brief explanation of the brunt The figure shows the durability test results of the example.

Claims (1)

[Claims] (1) A copolymer of polyα-olefin as a base oil and normal butylene mainly composed of isobutylene having a kinematic viscosity of 2,000 to 50,000 cst at 40°C 2 to 30
Weight % and alkylphenol aldehyde resin 0.2~
10% by weight of molybdenum disulfide, 2 to 20% by weight of molybdenum disulfide, and 3 to 15% by weight of lithium soap.