KR101267942B1 - Rubber components of O-ring for refrigerant compressor - Google Patents

Abstract

The present invention discloses a rubber composition of an O-ring for a refrigerant compressor having excellent gas shielding properties. The rubber composition of the O-ring for a refrigerant compressor according to a preferred embodiment of the present invention for achieving the above object is a polymer composed of HNBR rubber having an ACN content of 30% to 38%, and 120 to 180 parts by weight relative to 100 parts by weight of the polymer A filler made of MT carbon black and soda-lime-borosilicate glass which is 1 to 5 parts by weight based on 100 parts by weight of the polymer.

Description

Rubber components of O-ring for refrigerant compressor

The present invention relates to a rubber composition of the O-ring to prevent leakage of the refrigerant and the freezer oil in the compressor applied to the refrigeration air conditioning apparatus, including the refrigerator.

The compressor is one of the main engines of the refrigerator which converts the refrigerant of low temperature and low pressure into gas of high temperature and high pressure and delivers it to the condenser.

The O-ring used here is a rubber part that serves to prevent leakage of refrigerant and freezer oil in an environment of high temperature and high pressure. O-rings for compressors are required to be resistant not only to refrigerants, but also to refrigeration oil, to low and high temperature and high pressure environments. When abnormality of compressor O-ring occurs, it may cause the decrease of freezer performance due to leakage of refrigerant and freezer oil.

Until now, the refrigerant has been mainly made of freon gas, and the material of the O-ring included in the refrigerant compressor is mainly HNBR rubber.

Freon gas is known as an ozone depleting substance and the alternative refrigerant carbon dioxide (CO2) is attracting attention, but due to the high permeability of the carbon dioxide gas is not applicable to conventional HNBR rubber.

That is, since carbon dioxide becomes high pressure and has high permeability and solubility to a generally used polymer material, foaming is likely to occur, and on the contrary, even if foaming does not occur, the polymer material itself permeates carbon dioxide, making pressure holding and sealing difficult.

Therefore, in order to lower the permeability of carbon dioxide, O-ring is applied as a butyl rubber composition (Japanese Patent Laid-Open No. 2002-053718) instead of the conventional HNBR rubber, or chlorinated polyethylene or a mixture thereof with vinyl chloride resin (WO 01/09237) is applied. The room was devised. However, in this case, heat resistance and abrasion resistance deteriorate, and thus are not suitable as an O-ring for a refrigerant compressor.

In order to compensate for this, HNBR rubber having an acrylonitrile bond (ACN content) of 40% or more is used as a polymer, and a method of blending a filler consisting of carbon black of 80 phr or less and 40 phr of graphite (Japanese Patent Laid-Open No. 2002-0800639, Korea) Patent Registration 10-0709920 may be considered. In this case, the ACN content is limited to 40% or more in order to prevent a decrease in the value of 20% modulus and a decrease in gas permeability, thereby deteriorating low temperature flexibility.

In addition, the use of graphite in addition to carbon black as a filler increases the cost, there is a problem that the manufacturing time is longer by adding a process.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a rubber composition of an O-ring for a refrigerant compressor having excellent gas permeability and low temperature flexibility and excellent wear resistance and heat resistance.

The rubber composition of the O-ring for a refrigerant compressor according to a preferred embodiment of the present invention for achieving the above object is a polymer made of HNBR rubber having an ACN content of 30% to 38%, and 120 to 180 parts by weight relative to 100 parts by weight of the polymer A filler made of MT carbon black and soda-lime-borosilicate glass which is 1 to 5 parts by weight based on 100 parts by weight of the polymer.

In this case, the HNBR rubber may further include barium sulfate having a polymer Mooney viscosity ML _{1 + 4} (100 ° C.) of 80 to 95 and 1 to 5 parts by weight based on 100 parts by weight of the polymer.

On the other hand, in another aspect of the present invention, a polymer made of HNBR rubber having an ACN content of 30% to 38%, a filler made of N990 carbon black 120 to 180 parts by weight based on 100 parts by weight of the polymer and 1 to 1 part by weight of 100 parts by weight of the polymer Provided is a rubber composition of an O-ring for a refrigerant compressor, comprising 5 parts by weight of barium sulfate.

11 to 20 parts by weight relative to 100 parts by weight of the polymer may further include a plasticizer. In this case, the plasticizer may be Bis (2- (2-Butoxyethoxy) Ethyl) Adipate.

The O-ring made of the rubber composition according to the preferred embodiment of the present invention satisfies heat resistance and low temperature flexibility, and at the same time satisfies gas shielding properties, thereby being applicable to a refrigeration and air conditioning apparatus having a carbon dioxide refrigerant.

In addition, since only the carbon black is used as the filler, the cost is reduced and the process is simplified.

Hereinafter, the rubber composition of the O-ring for the refrigerant compressor according to the preferred embodiment of the present invention will be described in detail. In this case, the refrigerant that can be applied to the present invention may be a gas refrigerant such as freon gas and carbon dioxide. More preferably, the present invention can be used in a refrigeration and air conditioning apparatus having a carbon dioxide refrigerant that is more difficult to shield gas than Freon gas.

The rubber composition of the O-ring for a refrigerant compressor according to a preferred embodiment of the present invention includes a polymer, a filler, and soda-lime-borosilicate glass.

The polymer consists of hydrogenated acrylonitrile butadiene copolymer rubber (HNBR rubber). In this case, the nitrile content is 30% to 38%.

On the other hand, by setting the ACN content of the HNBR rubber to 38% or less, the low temperature flexibility is improved as compared to the HNBR rubber having a conventional ACN content of 40% or more.

If the ACN content is less than 30%, the gas permeability is significantly increased and there is no carbon dioxide shielding effect.

Fillers are intended to improve the adhesion of the polymer while improving processability and reinforcement. In this case, the filler is preferably made of MT carbon black of 120 to 180 parts by weight based on 100 parts by weight of the polymer.

MT carbon black is referred to as neutral thermal carbon black, and means that the particle diameter of the carbon black molecules is 201 to 500 nm. In this case, the carbon black is more preferably N990 (ASTM CODE).

In the present invention, carbon black is filled in excess of the usual filler amount. Usually, carbon black is blended at 100 parts by weight or less. As a result, the void space between the polymer molecules can be filled to increase the density, thereby providing excellent gas shielding properties.

In addition, by using carbon black having a large particle diameter, kneading is possible even if an excessive amount of carbon black is added. If the carbon diameter is smaller than the present invention is applied to the carbon black kneading is not good, even if the kneading is excessively high hardness loses elasticity, there is a problem in the application of the product.

According to the present invention, by using carbon black having large particles and applying the carbon black in excess, gas permeability is improved. In this case, only carbon black may be used as the filler. That is, for gas shielding, a separate material (for example, graphite) other than carbon black is unnecessary. This reduces the material cost and simplifies the process.

The excessive increase in hardness that may occur due to overfilling can be prevented by adding too much plasticizer. Plasticizers are substances that are added to improve the processability of rubber and at the same time give the product flexibility. Conventionally, the plasticizer was added at about 2 to 10 phr. However, in the present invention, by excessively kneading the plasticizer to 11 to 20 parts by weight, it is possible to solve the hardness problem due to overfilling of the carbon black. In this case, the plasticizer may be Bis (2- (2-Butoxyethoxy) Ethyl) Adipate.

In addition, deterioration of heat resistance and abrasion characteristics that can occur by applying only carbon black as a filler can be compensated by blending a certain amount of soda-lime-borosilicate glass and / or barium sulfate.

Soda Lime Borosilicate Glass is a free, spherical formulation. Empty inside, specific gravity is very low, 0.125 ~ 0.6 g / cc.

The soda lime boro silicate glass is a spherical product that improves the flowability of the polymer during processing. In addition, since the inside of the particle is hollow, heat can be prevented from being transferred to the inside, and heat insulation effect can be expected. In addition, since the particles made at a high temperature of 600 ℃ glass component is excellent thermal stability is complemented by heat resistance, wear resistance is also complemented. Therefore, heat and wear resistance are secured even when carbon black is used as a filler. In this case, the soda lime boro silicate glass may be GLASS BUBBLE of 3M Co., Ltd.

Meanwhile, the HNBR rubber may have a polymer Mooney viscosity ML _{1 + 4} (100 ° C.) of 80 to 95. By increasing the polymer Mooney viscosity of 80 or more, the mechanical properties are improved. Conventionally, the Mooney viscosity of less than 75 is used for the moldability and kneading property of the rubber. However, this problem is solved by incorporating barium sulfate as an additive.

Barium sulfate (BASO4) is produced by grinding natural barite or by chemical reaction. Barium sulfate is usually used as a white pigment. That is, when the rubber needed to give a white color, the barium sulfate was used in a mixture of 1 phr or less.

 However, in the present invention, the barium sulfate is stable to heat and solvent, and functions to complement the heat and oil resistance properties in the formulation using only carbon black. In addition, the barium sulfate particle diameter is very fine, 0.1 ~ 1 micrometer, there is also a reinforcing effect of tensile strength, tear strength. In addition, the kneading with the rubber is good, it is helpful to improve the processability in the blended polymer is applied. In this case, the barium sulfate may be a Blanc Fixe product of Solvay.

That is, in the present invention, the gas-blocking property is blocked by adding an excessive amount of carbon black only filler, and the heat resistance and abrasion resistance deteriorated by blending only carbon black as a filler can be compensated by blending barium sulfate and / or soda lime boro silicate glass. Can be. In addition, the hardness due to the excessive blending of the filler can be adjusted by the excessive blending of the plasticizer.

In addition, low-temperature flexibility was ensured by using HNBR rubber having a low ACN content in the polymer, and the Mooney viscosity was increased to improve mechanical properties.

On the other hand, the present invention may further comprise a crosslinking agent, a crosslinking aid, and an anti-aging agent.

The cross-linking agent functions to cross-link the monomers constituting the rubber composition. In this invention, a peroxide vulcanization system can be used as a crosslinking agent. In this case, the crosslinking agent preferably has 5 to 10 parts by weight based on 100 parts by weight of the polymer.

Antiaging agents serve to prevent aging of organic polymeric materials. Antioxidants act to stop the chain reaction of automatic aging by oxygen, a major factor in aging. In the present invention, 2,2,4-Trimethyl-1,2-dihydroquinoline and SUNNOC (Daerae Shinheung) can be applied as an anti-aging agent, and in this case, it may have a content of 1 to 5 parts by weight per 100 parts by weight of the polymer.

The crosslinking aid is for increasing the crosslinking density of the rubber composition while preventing side chain reaction. The crosslinking aid of the present invention may be applied with stearic acid and magnesium oxide, in this case may have 1 to 3 parts by weight relative to 100 parts by weight of the polymer.

Understand that the rubber composition of the thermostat O-ring of the vehicle according to the present invention as described above is excellent in low temperature flexibility and excellent heat resistance at the same time as the rubber composition of the thermostat O-ring of the conventional vehicle more clearly by Table 1 and Table 2 below. Can be.

 Table 1 shows the composition of the O-ring for the refrigerant compressor according to the present invention (hereinafter referred to as "Example") used in this experiment and the rubber composition of the O-ring for the conventional CO2 refrigerant compressor (hereinafter referred to as "Comparative Example"). It is shown by comparing the material constituting the.

In the examples, HNBR rubber having a lower ACN content than the comparative example was used as a polymer, and the filler was used in excess of MT carbon black. In addition, the plasticizer was also blended in excess compared to the comparative example, and barium sulfate was newly added.

Components (parts by weight) Comparative example Example Polymer ZETPOL 1020 ¹⁾ 100 0 ZETPOL 2010 ²⁾ 0 100 Filler N990 ^{3 )} 50 150 Cross-linking agent PERCUMYL D ^{4 )} 7 7 Crosslinking auxiliary MgO ^{5 )} 5 5 Steaic Acid ^{6 )} One One Antioxidant VULKANOX HS / LG ^{7 )} One One SUNNOC ^{8 )} One One Plasticizer RS-107 ⁹⁾ 0 20 additive Blanc Fixe ^{10 )} 0 3 1) Zetpol 1020: ACN content 44.2% HNBR POLYMER, ZEON
2) Zetpol 2010: ACN content 36.2% HNBR POLYMER, ZEON
3) N990: MT Carbon black, Cancarb
4) PERCUMYL D: Dicumyl Peroxide, NOF
5) MgO: Magnesium oxide, KYOWA Chemical
6) Stearic Acid: Stearic Acid, NATOLEO
7) VULKANOX HS / LG: 2,2,4-Trimethyl-1,2-dihydroquinoline, Lanxess
8) SUNNOC: Selected Special Wax, 大 來 新興
9) RS107: Bis (2- (2-Butoxyethoxy) Ethyl) Adipate, ADENKA
10) Blanc Fixe: BaSO4, Solvay

Table 2 is a table comparing the physical properties of the Example and Comparative Example results of the freezer oil deposition test, low temperature recovery test, and compression test. In this case, the freezer oil deposition test was observed for 70 hours in the ambient atmosphere of 150 ℃ after the hardness change was observed, satisfying the specifications of KS M 6518.

The low temperature recovery test was a test of deformation recovery in the low temperature region, and the TR-10 cold resistance test was performed. TR-10 refers to a test for measuring the temperature when 10% recovery of 50% of the strain applied in advance is carried out while methanol was deposited. Also in this case, the standard of KS M 6518 was satisfied.

The compression test was observed for 70 hours in the ambient atmosphere at 150 ℃ and observed the change in compression permanent strain, and satisfies the standard of KS M 6518.

In addition, the actual environmental test was carried out for 6 months by mounting on a compressor of a refrigerator using carbon dioxide.

As a result, in the low temperature recovery test, the Example can recover at a temperature much lower than -16.5 占 폚 of -29.6 占 폚 when 10% recovery. Through this, it can be seen that the embodiment is excellent in low temperature recovery.

In addition, as a result of the compression set (%) test through the compression test, it can be seen that the embodiment has the same compression set as the comparative example, the mechanical properties are not deteriorated and equivalent to the conventional ones.

In addition, it can be seen that the embodiment in the refrigeration oil deposition test is reduced in volume to reduce the volume expansion effect due to the penetration of carbon dioxide to improve durability.

On the other hand, the comparative example caused a problem that the performance of the refrigerator deteriorated through the actual environment evaluation, it was found that the embodiment is a material suitable for carbon dioxide by maintaining the performance.

As described above, the rubber composition of the O-ring for a refrigerant compressor according to the embodiment of the present invention is excellent in low temperature flexibility and improved in permeability as compared with the comparative example.

Item Comparative example Example Related Standard Freezer oil deposition
(150 ℃ × 70H) Volume change rate (%) +0.3 -5.1 KS M 6518 Low temperature recovery test
(Methanol deposition) TR-10 (℃) -16.5 -29.5 KS M 6676 Compression test
(150 ℃ × 70H) Compressed permanent reduction rate (%) 23 23 KS M 6518 Product Evaluation
(Mounted environment) Refrigerator Performance TEST FAIL PASS -

As described above, although described with reference to the preferred embodiment of the present invention, those skilled in the art various modifications and variations of the present invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

Claims (5)

Polymers consisting of HNBR rubber having an ACN content of 30% to 38%;
Filler consisting of MT carbon black of 120 to 180 parts by weight based on 100 parts by weight of the polymer;
1 to 5 parts by weight of soda lime boro silicate glass (soda-lime-borosilicate glass) relative to 100 parts by weight of the polymer; And
1 to 5 parts by weight of barium sulfate relative to 100 parts by weight of the polymer;
O-ring rubber composition for a refrigerant compressor comprising a. The method of claim 1,
The HNBR rubber is a rubber composition of the O-ring for refrigerant compressors, characterized in that the polymer Mooney viscosity ML _{1 + 4} (100 ℃) is 80 to 95. Polymers consisting of HNBR rubber having an ACN content of 30% to 38%;
Filler consisting of MT carbon black of 120 to 180 parts by weight based on 100 parts by weight of the polymer; And
1 to 5 parts by weight of barium sulfate relative to 100 parts by weight of the polymer;
O-ring rubber composition for a refrigerant compressor comprising a. 4. The method according to any one of claims 1 to 3,
Rubber composition of the O-ring for a refrigerant compressor further comprises a plasticizer of 10 to 20 parts by weight based on 100 parts by weight of the polymer. 5. The method of claim 4,
Said plasticizer is Bis (2- (2-Butoxyethoxy) Ethyl) Adipate rubber composition of the O-ring for the refrigerant compressor, characterized in that.