JPH04149292A - Moisture-proof mixture for connector - Google Patents

Abstract

PURPOSE:To provide the subject mixture containing a base oil composed mainly of an alpha-olefin synthetic oil and a silica-based inorganic material, preventing the corrosion and rusting of contact material, durable to long-term use and useful for communication cable. CONSTITUTION:The objective mixture is composed of (A) 70-82wt.% of a base oil composed mainly of an alpha-olefin synthetic oil and (B) 18-30wt.% of a silica- based inorganic material consisting of amorphous silica having an average diameter of about 10mmu and a specific surface area of 50-380m<2>/g (depending upon the kind of the silica).

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a moisture-proof mixture for connectors.

[Conventional Technology] Conventionally, when a telephone was brought into a home, etc., the cable from the exchange and the drop-in line were connected inside a terminal box using a connector.

This connector is made of plastic and has very good insulation properties.

Although the area where the connector is used is covered, the connection parts are easily affected by the outside air, and in order to prevent the connector terminals and core wire connections from corrosion and rust due to moisture, etc. Silicone grease was injected.

However, these silicone-based greases that have been used conventionally have the following major drawbacks and have caused numerous problems in use.

1) Silicone oil has a strong corrosive effect on copper-based alloys, so silicone grease is applied to copper-based alloy contacts, which are widely used in connectors and other electrical contacts, for long periods of time. Over time, this corrodes that part, which increases the resistance value and reduces the current-carrying characteristics, creating conditions that make it easy to generate sparks, and ultimately causing serious consequences such as burning out the contacts. .

2) It is very difficult to form a grease-like composite using silicone oil as a base, which has a high oil separation property, and many patents have been filed so far, but It is humbling to know that there is currently no established method for forming a good grease structure.

Therefore, since silicone-based greases made using current technology are commercialized after forming a good grease structure, many drawbacks have been pointed out, and one of them is that there is a lot of oil separation. Things are mentioned.

After long-term use, oil oozes out from the grease, which not only contaminates other parts, but also when used for connectors, etc., oil separates from the grease itself that was applied to fill the gaps created by crimping. A new space is created there, which invites foreign matter to enter from the outside, causing troubles such as corrosion. In this way, the performance as a connector deteriorates, resulting in serious consequences. become. Therefore, low oil separation is an essential condition for a moisture-proof mixture for connectors.
Current silicone-based greases do not have a performance that fully satisfies such performance.

3) Outflow of grease due to oral changes As mentioned earlier, there are many technical challenges in making grease compositions using silicone oil as a base, and some have not yet been fully resolved. There are many left. One of them is
As mentioned above, the inability to form a stable grease structure results in products with a high degree of oil separation, and in addition to this, there is the problem of grease softening over time. When the grease softens, it eventually becomes almost oil-like, which causes a leakage phenomenon, causing problems similar to the oil separation described above. In the past, when silicone grease was used for connectors, about a month after the grease was injected, the grease began to soften over time, and the original purpose of filling spaces and exhibiting sealing performance was lost. There have been times when I have not been able to perform to my full potential and caused major problems.

4) Silicone oil is expensive compared to other synthetic oils, and it also has serious problems in grease production, so the price of silicone grease is high and it is a big deal from an economic standpoint. I have a problem.

[Problem to be solved by the invention 1 The following items are listed as the performance required of the moisture-proof mixture for connectors of communication cables.

1) Provide good lubricity when crimping connector terminals.

2) It fills the small gap that occurs after crimping, prevents foreign matter from entering from the outside, and also does not reduce sealing performance against changes in the external environment such as humidity and water.

3) The parts after crimping should maintain a high degree of insulation, and there should be no leakage of current to other parts than necessary.

4) It is a necessary and sufficient condition that the contact parts connected by crimping should not be corroded, thereby causing an increase in electrical resistance and causing a trigger for spark generation.

5) It is necessary that the moisture-proofing mixture itself has little oil separation, does not cause leakage phenomena due to aging, and maintains good sealing performance.

The above are the performances required of a moisture-proof mixture for communication cable connectors, and the grease composition of the present invention solves many of the problems of silicone-based greases that have been used for such applications, and The purpose is to provide an effective moisture-proof mixture that satisfies the performance required for connectors.

[Means for Solving the Problems] The present invention provides a base that can easily generate a grease-like composition without relatively affecting various plastic materials, and can form a stable grease structure. For connectors that use oil, or form a grease-like composition with various metal soaps, non-soaps, organic substances, etc., and that contain 2% or more of silica-based inorganic substances as an essential component. It is an effective composition as a moisture-proofing admixture.

Paraffin mineral oil, liquid paraffin α-olefin synthetic oil, and alkylene glycol are examples of base oils that do not affect various plastics.

When forming a grease composition using these base oils with thickeners such as various metal soaps, non-soaps, and organic substances, it is relatively easy to obtain a grease composition that maintains a stable grease structure. I can do it.

On the other hand, with silicone oil and fluorine oil, it is relatively difficult to obtain one that maintains a stable grease structure, so it is necessary to use something other than silicone oil and fluorine oil as the base oil.

A "stable grease structure" here refers to a structure in which the shape of the micelles is uniform and has little variation, and has a three-dimensional spread.By obtaining a grease composition with such a stable structure, It has become possible to create good products with less oil separation and less change over time.

Furthermore, a silica-based inorganic substance is added as an essential component to the moisture-proof mixture of the present invention, but the purpose of this is to further improve the insulation properties of the connector, or By using a larger amount than usual, it became possible to further improve the insulation properties of the connector.

One part of the connector has a copper-based alloy contact inside which connects the core wire, and the entire connector is made of plastic covering all of these contacts. Both ends of the communication cable to be connected are inserted from the end of this part to the contact point, and then the external plastic part is pressed with strong force to plastically deform it to make the connection. When crimping in this way, a moisture-proof mixture is applied to the terminal parts to be connected, and its role is to fill minute gaps and prevent foreign matter from entering from the outside, and to provide a high degree of insulation. It's about preserving.

Maintaining a high degree of insulation over a long period of time is one of the important properties of a moisture-proofing mixture for connectors, and for this purpose the silica-based inorganic material used in the present invention is particularly useful, with 2% It has been discovered that effective insulation can be obtained by adding the above.

In general, silicone-based grease has been widely used as an insulating material for electrical parts, and the reason why silicone-based grease has been used for a long time for connectors is that it maintains high insulation properties.

However, the moisture-proof mixture of the present invention has succeeded in obtaining a moisture-proof mixture with a stable grease structure by using a base oil other than silicone oil that is resistant to plasticity.
This creates a grease composition that does not cause gaps in the connector due to oil separation or grease leakage, which causes foreign matter or moisture to enter, and which does not cause problems such as poor insulation, corrosion, or rust, and maintains a higher level of insulation. In order to achieve this goal, we have discovered a composition with the addition of a silica-based inorganic substance, which is effective as a moisture-proof mixture for connectors and retains a high degree of insulation for a long period of time.

The present invention is characterized by the following configuration.

That is, the first aspect of the present invention is a moisture-proof mixture for connectors, characterized by comprising 70 to 82% by weight of a base oil mainly composed of α-olefin synthetic oil and 18 to 30% by weight of a silica-based inorganic substance. , the second aspect of the present invention is a grease that mainly uses α-olefin synthetic oil, paraffinic mineral oil, or alkylene glycol synthetic oil as the base oil and thickens it with a thickener to 80 to 88% by weight; A moisture-proof mixture for connectors characterized by comprising 2 to 20% by weight of a silica-based inorganic substance.

α-olefin synthetic oils, paraffin mineral oils, or alkylene glycol synthetic oils, which are mainly used as base oils, do not have much of an effect on plastics, such as swelling or cracking, and are compatible with various thickeners. It is a type of oil that can easily form a stable grease structure even when used.

The grease composition according to this example uses, in addition to the above-mentioned base oil, various thickeners necessary for forming the grease composition.

Examples of thickeners include conventionally known metal soaps, inorganic thickeners, organic thickeners, and the like. The metal parts of metal soap include sodium, potassium, calcium,
Examples include barium, strontium, aluminum, and lithium.

The fatty acid portion of the metal soap includes various higher fatty acids or mixtures of higher fatty acids, these higher fatty acids and other acids,
Examples include so-called complex type thickeners obtained in combination with acetic acid, benzoic acid, boric acid, dicarboxylic acids, salicylic acid, etc.

The above-mentioned higher fatty acids are generally esters contained in animal oils, vegetable oils, waxes, etc., or artificially synthesized chain fatty acids.

Representative examples of such fatty acids include myristic acid,
Examples include saturated fatty acids such as valmitic acid and stearic acid, unsaturated fatty acids such as oleic acid, and fatty acids having substituents such as 12-hydroxystearic acid.

Specifically, inorganic thickeners include clay, bentonite,
Colloidal silica, silica airgel, alumina, graphite,
Examples include mica, talc, clay, diatomaceous earth, etc.

The organic thickeners generally include urea-based thickeners. A representative example of this is Patent No. 1272824 (Special Publication No. 11920/1982), which the applicant has already obtained.
In addition to urea grease, diurea grease (USP
2710889, 2710840, 2710841) and tetraurea grease (Japanese Patent Publication No. 39-3114). Other polyurea series #! Examples of thickeners include reaction products obtained by reacting incyanate and amine in a solvent or base oil. It can be provided as a useful grease composition as a gentle polyurea grease even as it is.

In addition, other organic thickeners include industhrene,
Phthalocyanine, amerine, etc. have soothing effects and can be used.

Furthermore, various kinds of antioxidants, extreme pressure additives, rust preventives, metal deactivators, etc. which are normally added can be appropriately blended and added to the mixture of the present invention, if necessary.

A useful component related to the present invention is a silica-based inorganic substance, which is amorphous silica, made by hydrolyzing silicon tetrachloride in an oxyhydrogen flame, and made by agglomerating several spherical particles. It forms an aerosol of 5102.

Various grades can be produced by changing operating conditions, and these grades are classified by specific surface area.

The average diameter of these spherical particles is only about 10 millimicrons, and a very large specific surface area can be obtained, ranging from 50 tn''/g to 380 tn''/g depending on the type.

The surface of the 5i02 aerosol particles is quite smooth and consists of a three-dimensional network structure of siloxane groups (-Sr-0-5I-0-). The silicon atoms on the surface do not have 4411 siloxane bonds,
The other one has an OH group, forming a so-called silanol group (-SI-0H).

The presence of silanol groups and their appropriate number (silanol group density) on the surface are important when thickening a liquid system.

These silanol groups create a three-dimensional network structure in each 5i02 aerosol particle, which develops into a complete gel structure when a certain concentration is reached.

Aerosols of 5102 are generally phyllophilic because silanol groups are present on the 5 surface and absorb moisture. However, this sil/-yl group is reactive with an organosilicon compound (for example, dimethylcyclosilane), and the reactivity can be eliminated by substitution with this. This method makes it possible to make hydrophobic and lipophilic silica at the same time, and this product is called AEROSrL R-972 (trademark, manufactured by Degussa, West Germany). This R-1117
Since 2 is hydrophobic, has thickening properties, and has excellent insulation properties, it is particularly useful as an additive in the present invention.

In other words, because it is hydrophobic, it can prevent moisture from entering from the outside, and because it has thickening properties, it is effective in preventing oil separation and bleeding, and it maintains useful properties as a moisture-proof mixture for connectors. It's something you get.

A typical manufacturing method for producing the moisture-proof mixture for connectors according to the present invention is as follows.

First, a grease composition using various soap-type, non-soap-type, organic substances, etc. as a thickener is formed using a general method for producing lubricating grease. As the base oil in this case, when considering plastic resistance, it is desirable to use α-olefin oil, liquid paraffin, paraffin mineral oil, or the like.

A silica-based inorganic material, preferably AEROSIL R-1172, is added to the base grease prepared in this manner, and the mixture is thoroughly dispersed and mixed. When dispersing these, a crosstalk device is used to ensure that these silica-based inorganic substances are well dispersed in the grease.

However, such cross-wire operation alone is often insufficient due to the formation of grains, so after this, a three-stage roll mill,
It is desirable to proceed with the dispersion of the 5i02 aerosol particles using a colloid mill or the like to obtain a uniform and smooth appearance.

[Example] Hereinafter, the present invention will be specifically explained in detail using examples.

<Example 1> The viscosity at 40°C was 33. 80% α-olefin oil, which is OC5T, and 0.5% phenolic antioxidant.
and heat while stirring to dissolve and disperse.

After that, let it cool and when it reaches room temperature, the silica-based inorganic material < AE
ROSIL R-972> (m mark, manufactured by Degussa, West Germany) 19.5% was added, mixed thoroughly using a mixer, and then milled on a three-roll mill to adjust the speed. <AERO
The usage amount of SIL R-972> can be up to 30%. As the amount of <AEROSIL R-972> used increases, the insulation properties of the mixture improve. However, if it exceeds 30%, the mixture becomes too hard.

<Example 2> First, urea grease was prepared based on paraffinic mineral oil having a viscosity of 93.3 C3T at 40°C. Add the entire amount of 3,3'-dimethyl 4,4'-biphenylene diisocyanate to the total amount of the lubricating base oil, and heat and dissolve at 80° C. while stirring. In a separate device, add the entire amount of amine to the remaining lubricant base oil, heat it to 80℃ and dissolve it, then add it to the device in which diincyanate was dissolved and mix thoroughly.
The mixture was stirred for 20 minutes at 0.degree. C. The mixture was then heated to 190.degree. C. at an average rate of 2.degree. C. per minute while stirring, and then allowed to cool.

Thereafter, 0.5% of a phenolic antioxidant and 0.1% of a metal deactivator were added, and when the mixture became uniform, it was passed through a three-roll mill to make it uniform and the adjustment was completed. At this time, the consistency of the base grease is the grade specified by JIS, No. 0,
Adjust to 0 (400-430) as necessary.

90% by weight of this base grease contains silica-based inorganic substances <AE
Add ROSIL R-972>10% by weight, mix thoroughly with a mixer, and then adjust using a three-roll mill.

<Example 3> First, an alkylene glycol synthetic oil having a viscosity at 40°C of 84.5 CST was used.
A bentonite-based grease was prepared based on Bentonite-based grease (trade name, manufactured by Sanyo Chemical Industry Co., Ltd.). Add Balaguer (trademark, Nashi, manufactured by Nal Red Corporation) as a raw material for an organic bentonite thickener to 1/2 of the total amount of lubricant base oil and stir well to make it homogeneous. Add the lubricant base oil little by little, stirring well and adding the entire amount over time. In this step, special care must be taken to ensure that the mixture is uniformly mixed, and sufficient stirring must be performed.

After this, methanol as a polar solvent is added and stirred well at room temperature to mix them thoroughly. After uniformly mixing, start heating and raise the temperature to 100°C to completely remove methanol, hold for 15 minutes, extinguish, and then leave to cool. After that, additives such as 0.5% phenolic antioxidant are added, and when the mixture becomes uniform, it is adjusted by passing it through a three-stage coal mill.

Next, 10% of a silica-based inorganic substance (HRO9IL R-972) is added to 80% by weight of this base grease, mixed thoroughly using a kneader, and then adjusted using a three-roll mill.

<Example 4> First, the viscosity at 40°C was 33. α which is OCST
- Olefin synthetic oil Mobile 5) IF-81> (
A lithium-based grease was prepared based on the trademark (manufactured by Mobil Oil Co., Ltd.). Approximately 1 of the total amount of lubricant base oil
/3 amount and the entire amount of fatty acids such as droxystearic acid are put into the pot and heating stirring is started. When the temperature reaches 85 to 35° C. after the fatty acids are dissolved, an amount of lithium hydroxide aqueous solution necessary to completely neutralize the added fatty acids is added. This step requires sufficient time to accelerate the reaction between the fatty acids and lithium hydroxide to form a lithium soap. After the dehydration step, the mixture is further heated and stirred until the temperature reaches 180 to 200°C, after which the heating is stopped and the remaining lubricating base oil is added and the mixture is rapidly cooled. Thereafter, stirring is continued and 0.5% of a phenolic antioxidant is added at a temperature below 120° C. After uniformly mixing, the mixture is passed through a disper mill or three-roll mill to obtain a base grease with a smooth appearance.

Next, 10% of a silica-based inorganic substance (ERO9IL R-872) is added to 90% by weight of this base grease, mixed well using a mixer, and then adjusted using a three-roll mill.

Comparative Example> In Comparative Example 1, dimethyl silicone oil having a viscosity of 100OcP at 25°C was
Comparative Example 2 is a moisture-proof admixture for silicone-based connectors made by another company.

The following tests were conducted for the above Examples and Comparative Examples. The results are shown in the table.

[Outline of test method] 1 Consistency - JIS K 2220 2, Pressure oil separation... ASTM D 17423, Volume resistivity... JIS K 87234, High temperature/high humidity test... Temperature 80°C, humidity 95 %, test M51)O)I
Measure the contact resistance and insulation resistance after r.

5. Metal corrosion test... under the conditions of high temperature and high humidity test #4
Apply a sample to one part of the wire and connector and check the degree of corrosion after the test is complete.

6. Heat cycle test: 1 hour at -30"C + 1 hour at 70"C, 6 cycles a day, 200 cycles in total, and the contact resistance is measured.The test is conducted with one part set. Do it with

7. Salt spray test: parts are exposed to conditions specified in JIS K 2220, and insulation resistance is checked after 500 hours. Temperature 35℃, HaC1 concentration 5%8, hydrogen sulfide test...Temperature 20"C, humidity 85%, concentration 200
PPM, check contact resistance after 200 hours test.

9. Vibration test: Check the contact resistance after the test.

・Vibration direction - direction perpendicular to the core wire φ amplitude - ±2.5 ■ intestine ・Speed - 10) 1z (800 times/min) Placement time - 72 hours 10. Outflow test: 70℃ after setting the parts.

Check for oil and grease leakage after 24 hours.

[Judgment Criteria] ・Contact Resistance - m - A maximum of 6 Ω or less after the test is judged to be passed (0) ・ Insulation Resistance - m - 1000 MΩ or more before and after the test is judged to be passed (0) [Effect of the invention ] In order to explain the effects of the present invention, the test properties are shown in a separate sheet.

The moisture-proof mixture for connectors according to the present invention is configured as described above and has the performance as shown in Table 1. Therefore, when it is used mainly for a part of a connector cover that connects telephone wires, it can be used to remove dust from the outside. In addition to preventing water from entering,
It maintains good insulation properties, prevents corrosion and rust of the contact material compared to conventionally used silicone types and other types, shows no phenomena such as oil leakage, and can withstand long-term use. It exhibits extremely effective performance as a moisture-proofing compound for communication cable connectors.

Claims (2)

[Claims] (1) Base oil 7 mainly consisting of α-olefin synthetic oil
A moisture-proof mixture for connectors, comprising 0 to 82% by weight and 18 to 30% by weight of a silica-based inorganic substance. (2) Grease 80 to 98, which uses α-olefin synthetic oil, paraffin mineral oil, or alkylene glycol synthetic oil as the base oil and thickens it with a thickener.
% by weight and 2 to 20% by weight of a silica-based inorganic substance.