KR102117366B1 - Method for modifying a rubber packing surface for an o-ring - Google Patents

Abstract

The present invention relates to a method of modifying a rubber packing surface for O-rings, and more particularly, to a method of coating a thin film of parlinine on a rubber packing surface for O-rings by improving adhesion between rubber and parlin. Through the surface modification method of the present invention, an O-ring excellent in chemical resistance, abrasion resistance, corrosion resistance, heat resistance and water resistance can be obtained.

Description

Method for modifying a rubber packing surface for an o-ring}

The present invention relates to a method of modifying a rubber packing surface for O-rings, and more particularly, to a method of coating a thin film of parlinine on a rubber packing surface for O-rings by improving adhesion between rubber and parlin.

O-ring is an annular material used to prevent leakage of various fluids such as liquid or gas between two separated contact surfaces, and is mainly made of rubber, silicone, or soft synthetic resin material. These O-rings are inserted into installation grooves formed in various mechanical parts or door operation parts that require airtight, that is, grooves, and are fixed and dynamic according to the operation of the installation parts. Can be distinguished.

Recently, with the rapid development of high-tech industries, O-rings are frequently used in semiconductor manufacturing facilities to prevent various contamination by micro devices. However, synthetic or natural rubbers are vulnerable to fire resistance, and when used for a long period of time in a state exposed to certain chemicals, there is a problem of cracking, corrosion, and curing. In addition, since the O-ring has a high surface frictional resistance, it is easy to be scratched or twisted when tightening. That is, since it has an abnormal stress in a fastened state, resistance is weak.

Accordingly, recently, a technique for coating a polymer on a rubber surface has been developed to impart low friction, non-adhesiveness, and abrasion resistance to O-rings, and such polymers are disclosed in Korean Patent Publication Nos. 10-2012-0088243 and 10-2009-0015009. As suggested, parylene excellent in water resistance, heat resistance, corrosion resistance, and chemical resistance is attracting attention. Paralin (poly (p-xylylene) polymer) is a polymer developed in the United States in the 1970s, and has low moisture permeability compared to other polymer membranes. In addition, paralin is widely used in the field of MEMS (Micro electromechanical system) because it can form a uniform and pinhole-free coating film along the uneven surface, and research and development is progressing as an insulator in the semiconductor process due to its low dielectric property. have. In addition, since paralin is harmless to the human body, recent research on coating of bio-related products has been actively conducted, and biochips, biosensors, medical equipment and parts have been actively applied.

However, since paralin has poor adhesion to a rubber material, there is a problem in that deformation occurs, such as when the thin film of the paraline is easily peeled off or worn out of the rubber when subjected to a strong impact. Accordingly, the present inventors have developed a method of stably coating the paralin thin film by increasing the adhesion between the paralin thin film and the rubber packing for O-ring.

Republic of Korea Patent Publication No. 10-2012-0088243 (Invention name: PDMS-based flexible electrode using a perylene coating layer and its manufacturing method, Applicant: Gwangju Institute of Science and Technology, Publication date: August 08, 2012) Republic of Korea Patent Publication No. 10-2009-0015009 (Name of invention: Method for manufacturing orthodontic wire, Applicant: Injae Kim, Publisher: February 11, 2009)

An object of the present invention is to provide a method for modifying the surface of a rubber packing for O-rings to increase the adhesion between a rubber packing for ducks and a thin film of parylene.

Another object of the present invention is to provide a coating method capable of preventing the peeling phenomenon of the paraffin thin film through the modification method.

In addition, another object of the present invention is to provide a rubber packing for O-ring excellent in abrasion resistance and chemical resistance through the coating method.

In order to achieve the above object, the present invention (step 1) washing and drying the rubber packing surface for O-ring with a solvent, followed by plasma treatment to perform a primary surface treatment;

(Step 2) Secondary surface treatment by immersing the primary surface-treated rubber packing for O-ring in an alkyltrialkoxysilane solution; And

(Step 3) After washing and drying the second surface-treated rubber packing for O-ring with a solvent, a method of modifying the rubber packing surface for O-ring is provided.

At this time, the rubber material applied to the rubber packing for ducks is acrylonitrile-butadiene rubber (NBR), acrylic rubber (ACM), silicone rubber (VMQ), fluoro rubber; FKM) and urethane rubber (AU), but is not limited thereto.

In the first step, the plasma treatment is preferably performed in the presence of one or more gases selected from the group consisting of air, hydrogen, nitrogen, oxygen, argon and ammonia.

The concentration of the alkyltrialkoxysilane in the solution of the alkyltrialkoxysilane in the second step is preferably 0.05 to 10% by volume.

In this case, the alkyltrialkoxysilane is methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltriisopropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane , Propyltriethoxysilane, butyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ- It may be at least one member selected from the group consisting of acryloyloxypropyl trimethoxysilane, γ-methacryloxypropyl trimethoxysilane, dimethyldimethoxysilane and methylphenyldimethoxysilane.

In addition, the immersion time of the rubber packing for O-ring in the alkyltrialkoxysilane solution in the second step is more preferably 10 to 60 minutes.

In the first or third step, the solvent is preferably one selected from the group consisting of methanol, ethanol, propanol, isopropanol, butanol, isobutanol or an aqueous solution thereof.

In the above step 3, it is preferable that the composition pressure during deposition of the paraline thin film is 5 to 20 mTorr.

Hereinafter, the present invention will be described in detail.

The present invention relates to a method of modifying a rubber packing surface for an O-ring capable of stably coating a thin film of a paralin by increasing the adhesion between the thin film and the rubber packing surface by performing a pre-treatment process of the rubber packing surface for the O-ring. The method includes: (Step 1) washing the rubber packing surface for O-ring with a solvent to remove foreign substances on the metal surface, drying, and plasma treatment, followed by primary surface treatment;

(Step 2) Secondary surface treatment by immersing the primary surface-treated rubber packing for O-ring in an alkyltrialkoxysilane solution; And

(Step 3) After the second surface treatment, the unreacted material is washed with a solvent, dried, and then formed on the surface of the rubber packing for O-ring to form a thin film of parylene.

The ones that can be used as a solvent in the first or third step are not particularly limited, but are preferably C ₁ to C ₄ alcohol or an aqueous solution thereof, and the C ₁ to C ₄ alcohol is, for example, methanol, ethanol, propanol, It may be one selected from the group consisting of isopropanol, butanol and isobutanol. In addition, the first and third stage solvents may be the same or different types.

The present invention is characterized in that surface treatment by immersing the rubber packing for O-ring in the alkyltrialkoxysilane solution in order to improve the adhesion between the rubber packing for O-ring and the thin film of paralin. The alkyltrialkoxysilane contains both a hydrophilic group and a hydrophobic group, and since the paralin thin film has hydrophobic properties, the paralin thin film shows a very good bonding with the hydrophobic group of the alkyltrialkoxysilane. That is, if the surface of the rubber packing for O-ring is treated with an alkyltrialkoxysilane solution, adhesion between the surface of the rubber packing for O-ring and the thin film of paralin can be improved. However, due to the hydrophilic group contained in the alkyltrialkoxysilane, there is a problem in that a sufficient surface modification effect cannot be obtained due to poor reactivity between the alkyltrialkoxysilane and the rubber packing for O-ring. Accordingly, the present invention is characterized in that it further comprises a step of plasma treatment to convert the surface of the rubber packing for O-ring to hydrophilicity before the surface treatment step using an alkyltrialkoxysilane.

In the first step, the plasma surface treatment may be performed in the presence of one or more gases selected from the group consisting of air, hydrogen, nitrogen, oxygen, argon and ammonia.

At this time, it is preferable that the gas is injected into the plasma device at a flow rate of 0.1 to 20 L / min. When the flow rate of gas injection is less than 0.1 L / min, the surface treatment is not sufficiently performed, and when it exceeds 20 L / min, it is not economical and is not preferable.

In addition, the applied voltage at the time of plasma generation is preferably 5 to 400 W. The higher the applied voltage, the higher the plasma discharge density, and the adhesion can be improved as the development of active functional groups on the rubber packing surface for O-rings increases.

In addition, a radio frequency of 12 to 14 MHz is applied to the plasma device, and the distance between the reaction gas, which is a plasma source, and the rubber packing surface for O-ring is 1 to 20 mm, and plasma treatment is performed at a speed of 1 to 60 mm / min. It is more preferably performed once at room temperature.

The primary surface treatment step through the plasma treatment configured as described above is to uniformly bond the alkyltrialkoxysilane to the rubber packing surface for O-ring, and ultimately, it is useful to significantly improve the adhesion and abrasion resistance, etc. of the thin film in the future. It works.

In the above step 2, the alkyltrialkoxysilane solution may be prepared by adding an alkyltrialkoxysilane to a solvent, and the concentration of the alkyltrialkoxysilane in the solution is preferably 0.05 to 10% by volume. When the concentration of the alkyltrialkoxysilane is less than 0.05% by volume, the surface treatment of the rubber packing for O-ring does not sufficiently occur, and when the parlin thin film is coated on the rubber packing surface for O-ring, peeling of the paralin thin film may occur. If it exceeds%, it is not preferable because a phenomenon in which a thin film of parylene is agglomerated occurs on the surface of the rubber packing.

In this case, the alkyltrialkoxysilane is a derivative having one carbon-silicon bond and three oxygen-silicon bonds, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltriisopropoxysilane , Ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, butyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, vinyltrimethoxysilane, vinyl Consisting of triethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-acryloyloxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, dimethyldimethoxysilane and methylphenyldimethoxysilane It may be one or more selected from the group.

In addition, those that can be used as the solvent is not particularly limited, but is preferably a C ₁ to C ₄ alcohol or an aqueous solution thereof, and the C ₁ to C ₄ alcohol is, for example, methanol, ethanol, propanol, isopropanol, butanol and It may be one selected from the group consisting of isobutanol.

In addition, the surface treatment method for improving the adhesion of the paralin thin film is not only the concentration of the alkyltrialkoxysilane solution, but also the process control of mixing the alkyltrialkoxysilane is more important. In order to improve adhesion, alkyltrialkoxysilane is added to a solvent, stirred for 10-60 seconds, and rested for 5-30 minutes to prepare an alkyltrialkoxysilane solution. When the pause time is less than 5 minutes, the effect of improving the adhesiveness of the thin film of the paraline is not sufficient, and when the pause time exceeds 30 minutes, an addition reaction of the alkyltrialkoxysilane occurs, which is not preferable.

In the above step 2, the immersion time of the rubber packing for O-ring in the alkyltrialkoxysilane solution is preferably 10 to 60 minutes. When the immersion time is less than 10 minutes, the surface treatment of the rubber packing does not occur sufficiently, so that when the parlin thin film is coated on the rubber packing surface, peeling phenomenon of the paralin thin film may occur, and when it exceeds 60 minutes, alkyl in solution The addition reaction of trialkoxysilane may cause a phenomenon in which a thin film of paralin is agglomerated on the surface of the rubber packing, which is undesirable.

In the above step 3, the paraline thin film may be coated through a chemical vapor deposition method (CVD), for example, a paraline dimer is inserted into the evaporator in powder form and evaporated in a gas phase at 120 to 180 ° C. The evaporated dimer is converted into monomers through a pyrolysis furnace heated to 650 to 700 ° C. The thermally decomposed monomers undergo a polymer polymerization reaction while colliding with the o-ring's rubber packing surface in the deposition chamber to form a thin film of paralin on the o-ring's rubber packing surface. The paralin dimer used at this time may be one selected from the group consisting of paralin-C, paralin-N, and paralin-D, and preferably, paralin-C is used. Further, when depositing a thin film of paralin, the composition pressure is 5 to 20 mTorr, and the deposition rate is more preferably 1.0 to 2.0 µm / hr. When the composition pressure and the deposition rate are less than the above range, the parline thin film is not sufficiently coated, and when it exceeds, the parlin thin film may be agglomerated, which is preferable. However, the method of coating the thin film of paralin on the rubber packing surface for O-ring is not limited thereto.

Through the method of modifying the rubber packing surface for O-ring provided by the present invention, adhesion between the rubber and the paraline can be maximized without affecting the water resistance and fire resistance of the paraline polymer.

In addition, by improving the adhesion, it is possible to prevent the peeling phenomenon of the paralin thin film coated on the rubber packing surface for O-rings, thereby obtaining an O-ring having excellent life, chemical resistance, abrasion resistance, corrosion resistance, heat resistance and water resistance.

1 is a photograph showing the molecular structure of various paralines.
2 is a scanning electron microscope (SEM) photograph showing a state in which a thin film of paralin is deposited on a rubber packing surface for O-rings according to an embodiment of the present invention.
3 is a scanning electron microscope photograph showing a state after acid treatment of the rubber packing surfaces for O-rings of Example 1, Comparative Example 1 and Comparative Example 2.
4 is a scanning electron microscope photograph showing a state after base treatment of the rubber packing surfaces for O-rings of Example 1, Comparative Example 1 and Comparative Example 2.
5 is a scanning electron microscope photograph showing a state after annealing and deforming the rubber packing for O-rings of Example 1, Comparative Example 1 and Comparative Example 2.

Hereinafter, a preferred embodiment of the present invention will be described in detail. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, it is provided to sufficiently convey the spirit of the present invention to those skilled in the art so that the contents introduced herein are thorough and complete.

Example 1 and Comparative Examples 1 to 7. Parallel film deposition on rubber packing for O-ring

Example 1.Parline thin film deposition according to the present invention

The rubber packing for O-rings washed with ethanol was subjected to primary surface treatment using RF 13.6 MHz capacitively coupled plasma (CCP) type equipment (Plasmart Inc. Korea). At this time, the vacuum chamber with a diameter of 325 mm and a height of 175 mm maintained a vacuum of up to 10 ^-3 Torr with a rotary pump, and the sample stand was located 15 mm away from the upper electrode. In addition, the gas used for the plasma surface treatment was a high-purity oxygen (99.99%) gas, and the gas was flowed at a flow rate of 10 L / min to maintain the chamber pressure at 50 mTorr, and then applied 100 W of input power for 180 seconds. Next, γ-methacryloxypropyl trimethoxysilane (MAPS) was added with a solvent prepared by mixing isopropanol and distilled water in a volume ratio of 1: 1, and γ-methacryloxypropyl trimethoxysilane was diluted to 0.5% by volume. Then, the mixture was stirred for 30 seconds, and then rested for 15 minutes to prepare an alkyltrialkoxysilane solution. Subsequently, the rubber packing for O-ring, which was primarily surface-treated in the prepared alkyltrialkoxysilane solution, was completely immersed for 20 minutes, then taken out and dried in the air for 20 minutes. Subsequently, the dried rubber packing for O-ring was washed with isopropanol and then dried with nitrogen to complete the second surface treatment. Subsequently, using a parylene deposition system (PDS-2060PC, SCS, USA), paralin was deposited to a thickness of about 5 μm on a rubber packing for O-ring, which had been surface-treated. At this time, the composition pressure was 10 mTorr and the deposition rate was 1.5 µm / hr.

Comparative Example 1. The first surface treatment step was not carried out

In the same manner as in Example 1, paralin was deposited on the rubber packing for O-rings, but proceeded without going through the first surface treatment step.

Comparative Example 2. Second surface treatment step not carried out

In the same manner as in Example 1, paralin was deposited on the rubber packing for O-rings, but proceeded without going through a second surface treatment step.

Comparative Examples 3 to 7. Alkyl trialkoxysilane solution preparation conditions or immersion time change

In the same manner as in Example 1, paralin was deposited on the rubber packing for O-ring, and the conditions for preparing the alkyltrialkoxysilane solution were shown in Table 1 below.

Condition Plasma treatment Silane concentration (% by volume) Stirring time (sec) Downtime (minutes) Immersion time (minutes) Example 1 practice 0.5 30 15 20 Comparative Example 1 Not implemented 0.5 30 15 20 Comparative Example 2 practice - - - - Comparative Example 3 practice 15 30 15 20 Comparative Example 4 practice 0.5 30 15 5 Comparative Example 5 practice 0.5 30 15 120 Comparative Example 6 practice 0.5 30 One 20 Comparative Example 7 practice 0.5 30 45 20

Evaluation Example 1. Confirmation of adhesion between the O-ring's rubber packing and the Paralin thin film

Evaluation Example 1-1. Comparison of adhesion through chemical treatment

The rubber packing for o-rings with paralin deposited through Examples 1 and 1 to 7 was acid treated with 95% (w / v) H ₂ SO ₄ aqueous solution and 90% (w / v) KOH aqueous solution for 24 hours, respectively. Alternatively, the conditions were compared after base treatment, and the results are shown in Table 2 below.

Adhesion comparison Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Acid treatment ○ Ｘ Ｘ ○ Ｘ ○ △ Ｘ base
process ○ Ｘ Ｘ ○ △ ○ △ Ｘ Remark - - - Clustering occurs - Clustering occurs - Clustering Adhesion evaluation criteria; ○: almost no fall of the thin film
△: The thin film falls partially.
Ｘ: Thin film is almost inferior

Referring to FIGS. 3, 4 and Table 2, in the case of Example 1, it was confirmed that the degree of damage of the paralin thin film was substantially less than that of Comparative Examples 1, 2 and 4, through which the adhesive force of the paralin thin film was It was excellent and it was found that the chemical resistance was improved. Therefore, it is necessary to include both the surface treatment steps of the present invention in order to improve the adhesion between the rubber packing for O-ring and the thin film of paralin.

On the other hand, in the case of Comparative Examples 3 and 5, the concentration of the alkyltrialkoxysilane was increased or the adhesive strength was increased as the immersion time of the rubber packing was increased.

In addition, when the alkyltrialkoxysilane solution is prepared through Comparative Examples 6 and 7, it can be seen that when the manufacturing conditions are outside the range of the present invention, sufficient adhesive strength improving effect cannot be obtained. When the time exceeded 30 minutes, there was a problem such as an addition reaction between the alkyltrialkoxysilanes and the aggregation phenomenon. Accordingly, it was confirmed that the production conditions of the alkyltrialkoxysilane solution capable of maximizing the adhesion of the paralin thin film on the O-ring's rubber packing surface were limited.

Evaluation Example 1-2. Comparison of adhesion through physical treatment

The rubber packing for o-rings with paralin deposited through Example 1, Comparative Example 1 and Comparative Example 2 was heated to 150 ° C. while applying a pressure of 800 kPa for 3 hours, and then slowly annealed by cooling to room temperature. After that, it was deformed 20% without heat and pressure, and the results are shown in Table 3 and FIG. 5.

Adhesion comparison Example 1 Comparative Example 1 Comparative Example 2 Deformation after annealing ○ Ｘ Ｘ Adhesion evaluation criteria; ○: almost no fall of the thin film
△: The thin film falls partially.
Ｘ: Thin film is almost inferior

With reference to Table 3 and FIG. 5, it was confirmed that in Example 1, the degree of damage of the parline thin film was little compared to Comparative Examples 1 and 2, and through this, the adhesive strength of the parline thin film was excellent, and the wear resistance was improved. It was found that it was improved.

Claims (7)

(Step 1) Washing and drying the rubber packing surface for O-ring with a solvent, followed by plasma treatment to perform a primary surface treatment;
(Step 2) secondary surface treatment by immersing the primary surface-treated rubber packing for O-ring in an alkyltrialkoxysilane solution having a concentration of 0.05 to 10% by volume for 10 to 60 minutes; And
(Step 3) washing and drying the rubber packing for the second surface-treated O-ring with a solvent to form a thin film of paralin;
The alkyltrialkoxysilane solution is a method of modifying the rubber packing surface for O-rings, characterized in that the alkyltrialkoxysilane solution is prepared by adding to the solvent and stirring for 10 to 60 seconds, and then rest for 5 to 30 minutes. According to claim 1,
Plasma treatment in the first step is a method of coating a thin film of paralin on a medical metal surface, characterized in that in the presence of at least one gas selected from the group consisting of air, hydrogen, nitrogen, oxygen, argon and ammonia. delete According to claim 1,
The alkyltrialkoxysilane is methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltriisopropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, propyl Triethoxysilane, butyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-acrylo Method for modifying a rubber packing surface for O-rings, characterized in that at least one member selected from the group consisting of monooxypropyl trimethoxysilane, γ-methacryloxypropyl trimethoxysilane, dimethyldimethoxysilane and methylphenyldimethoxysilane. . delete According to claim 1,
Method of modifying the rubber packing surface for O-ring, characterized in that the solvent in step 1 or 3 is one selected from the group consisting of methanol, ethanol, propanol, isopropanol, butanol, isobutanol or an aqueous solution thereof. According to claim 1,
The method of modifying the rubber packing surface for O-ring, characterized in that the composition pressure during deposition of the parline thin film in step 3 is 5 to 20 mTorr.

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