KR20110000043A - Cryogenic binder and adsorption panel using the binder for cryo-pump - Google Patents

Abstract

PURPOSE: A cryogenic binder is provided to maintain adhesive strength and properties and to ensure excellent adhesion maintained at an ultralow temperature for a long time. CONSTITUTION: A cryogenic binder comprises an epoxy-based resin and an organic/inorganic hybrid type nanomaterial. The organic/inorganic hybrid type nanomaterial is polyhedral oligomeric silsesquioxanes. The epoxy-based resin is at least one selected from a group consisting of a bifunctional epoxy resin and a tetrafunctional epoxy resin.

Description

Cryogenic binder and adsorption panel using the binder for cryo-pump}

The present invention relates to a cryogenic pump including a cryogenic binder having excellent adhesion at cryogenic temperatures and excellent thermal stability even in repeated thermal cycling, and an adsorption panel bonded to the adsorbent.

In order to meet the demand for high integration, high yield, and low defect of semiconductors, displays, portable terminals, etc., development of process equipment for product production must precede. One of the most important technologies in these process equipment is vacuum technology. In addition to the electronics industry mentioned above, vacuum technology plays a key role in the research and production of aerospace, physics and materials engineering.

In particular, in order to form an electronic circuit in a semiconductor device or the like, sputtering equipment capable of depositing a metal or the like in a thin film form is essential, and this process is always performed in an ultra-high vacuum state.

Currently, there are many techniques for achieving ultra-high vacuum, but cryogenic vacuum pumps capable of removing all gases including hydrogen and helium have recently been widely used in ultra-high vacuum. In such cryogenic vacuum pumps, activated carbon is used as an adsorbent to remove hydrogen and helium gas.

An example of the cryogenic vacuum pump is a “Cryo Pump”, which is provided with a cryogenic (-260 ° C.) surface in a vacuum vessel to condense or adsorb gas molecules in the vessel to provide ultra-high vacuum (10 ^-8 torr). ), The actual picture of the cryo pump and the working principle and structure are shown in FIGS.

The freezer used in the cryopump consists of two stages, in which it is cooled to -193 ° C or lower in one step, and then to -260 ° C in two steps. The reason why such cryogenic temperature is required is to remove the residual high vapor pressure hydrogen (H ₂ ), helium (He), neon (Ne), etc. in order to make ultra-vacuum. It must be condensed before it can be removed.

Next, the 15K-Cryopanel of FIG. 2 plays a key role of removing hydrogen (H ₂ ), helium (He), and neon (Ne) gases, and the condensed gas is removed in the form of being adsorbed to the panel. It is called an adsorption panel.

3 shows the adsorption panel in the cryopump. (a) is a copper (Cu) substrate plated with chromium (Cr), and active carbon for adsorbing hydrogen (H ₂ ), helium (He), and neon (Ne) on the substrate (b), It was attached as shown in (c). The activated carbon is in a state of being attached by a binder as illustrated in (d).

The cryogenic binder used to attach activated carbon to the surface of the chromium plated copper substrate repeats cycling between -260 ° C and room temperature while the cryo pump is in use. Due to the thermal shock generated in this process, the adhesive strength between the cryogenic binder and the activated carbon decreases, causing the cryogenic binder to fall off from the adsorption panel together with the activated carbon.

Next, Figure 4 is a photograph showing a state in which the adsorbent is desorbed from the adsorption panel of the cryo pump. As such, the existing cryogenic binder lacks adhesive force and thus peels off during use, and thus a phenomenon in which the ultra-low vacuum degree falls is causing problems in the process.

As such, when activated carbon adsorbent is desorbed from the adsorption panel, it cannot be used repeatedly and should be replaced regularly. In this case, although the adsorption metal substrate (Fig. 3 (a)) itself can still be used, the entire set of 15K-Cryo panels with activated carbon must be purchased from the cryopump manufacturer, resulting in significant economic losses and burdens. Big. The key technology in the 15K-Cryopanel set is the cryogenic binder, which can be freed from such economic burdens if only this material is obtained.

Currently, no relevant research is being conducted in Korea, and the business relies on imports for the entire 15K-Cryo panel set.

The cryogenic binder currently being developed is a material exhibiting rubbery elasticity even at low temperatures such as polyurethane, epoxy, silicone resin, fluororesin, and phosphazene. Cryogenic binders are widely used in LNG carriers.

Research and development up to now is to make the binder for cryogenic performance mainly during long-term storage at cryogenic temperatures. However, in the case of the cryogenic binder for the adsorption panel used in the cryogenic vacuum pump such as the cryo pump, since the thermal cycling is repeated, it must have physical properties as shown in Table 1 below so that it can be used in such a special environment.

division Qualitative Goal Quantitative goals fair
characteristic Housework time Sufficient pot life for easy replacement 4 hours or more at 25 ℃
(Viscosity change) Initial viscosity Appropriate initial viscosity for the attachment of active stages and smooth panel production 15,000-30,000 cPs Hardening
characteristic durability
(Thermal shock resistance) Long-term reliability for repeating thermal cycling between -197 ℃ and room temperature 50 CYCLE or more
(After attaching activated carbon) Adhesive strength Increased durability through improved adhesive strength between metal panels and binders 10-15 MPa
(Lap shear test) Glass transition temperature (T _g ) Control of T _g Value by Control of Formulation T _g 40-50 ℃
(DSC method) Reaction rate
(Cure condition) Minimize reaction rate affecting binder properties More than 95%
(DSC method) Application field Adsorption Panel Activated Carbon for Cryopump

However, since the cryogenic binder that satisfies the above properties has not been developed yet, and the conventional binder is entirely dependent on foreign imports, it is urgent to develop a binder that can replace the binder.

In the present invention, to solve the problems of various technologies appearing in the conventional cryogenic vacuum pump, the object of the present invention can exhibit the adhesive performance during a long time at low temperature, as well as the adhesive performance in a special environment in which thermal cycling is repeated It is to provide this excellent cryogenic binder.

Another object of the present invention is to provide a cryogenic vacuum pump including an adsorption panel in which the cryogenic binder is adhered to an adsorption material.

In the present invention, by using an epoxy resin as a base resin, in order to impart cryogenic properties to the base resin, by including the organic / inorganic hybrid nanomaterial POSS (Polyhedral oligomeric silsesquioxanes) can not only maintain the long-term adhesion performance at low temperature Even if the thermal cycling is repeated, the cryogenic adhesion performance is excellent and thus the above problems can be solved.

The cryogenic binder according to the present invention is used in a special environment among various functional adhesive materials, and requires a high level of compounding technology, which is likely to be applied to various fields and greatly reduces costs in the electronic industry using ultra-high vacuum equipment. It can work. In addition, it can be widely applied to petroleum, shipbuilding (ultra low temperature insulation panel for LNG carriers), aerospace (rocket in cryogenic environment), chemical industry (various cryogenic liquid gas bottles), and thus has high economic and industrial expectations.

Cryogenic binder for achieving the object of the present invention is characterized in that it comprises an epoxy-based resin and organic / inorganic hybrid nanomaterials.

In addition, the cryogenic vacuum pump for achieving another object of the present invention is characterized in that it comprises an adsorption panel formed by adhering the cryogenic binder with the adsorbent.

Hereinafter, the present invention will be described in more detail.

The binder according to the present invention comprises an epoxy resin as a base resin, and includes organic / inorganic hybrid nanomaterials, and further includes a curing agent, a catalyst, and other additives.

The term "cryogenic" as used throughout the specification of the present invention means a temperature below the liquid nitrogen temperature (-197 ° C).

The base resin used in the cryogenic binder of the present invention uses an epoxy resin, specifically, selected from the group consisting of bifunctional and tetrafunctional epoxy resins.

The bifunctional epoxy resin is equivalent to 175g to 300g, and specific examples thereof include, for example, diglycidyl ether of bisphenol-A and diglycidyl ether of bisphenol-F. ether of bisphenol F), and diglycidyl ether of biphenyl.

In addition, the tetrafunctional epoxy resin is equivalent to 90g to 150g, specific examples are di- (4-diglycidylaminophenyl) methane (di (4-diglycidylaminophenyl) methane), and tetraglycidyl meta-styrene At least one selected from the group consisting of diamines (tetraglycidyl meta-xylene diamine) is preferred.

In the present invention, in particular, by adding the cryogenic properties of the cryogenic binder to improve the thermal properties and at the same time to enhance the mechanical properties, an organic / inorganic hybrid nanomaterial is added. Specifically, the polyhedral oligomeric silsesquioxane ( polyhedral oligomeric silsesquioxanes (POSS).

The POSS has a polyhedral structure having a molecular arrangement as shown in the following Structural Formula 1, and has a unique property as a compound closely related to silicon, and is a hybrid type of silica (SiO ₂ ) and silicon (R ₂ SiO) in terms of chemical composition. Has an intermediate component (RSiO _1.5 ).

Structural Formula 1

In addition, the POSS is known to exhibit various intermediate properties of the polymer material and the ceramic as shown in FIG. Accordingly, the POSS can be innovatively improved in performance (thermal and physical properties, etc.) required by mixing with a polymer material without significantly or substantially changing the existing mass production process through copolymerization or blending due to chemical properties.

In the present invention, the use of the POSS is expected to have an effect of increasing glass transition temperature, improving mechanical properties, decreasing viscosity, increasing thermal resistance, and improving the compatibility of the blend. In addition, by using POSS, the processability is excellent due to the high compatibility and reduction of the mixing viscosity when mixing with the epoxy base resin, and it is possible to obtain a mixture in which POSS is uniformly mixed. It possesses an appropriate coefficient of thermal expansion and maintains the adhesive strength for a long time during thermal cycling to satisfy the required characteristics of the cryogenic binder to be obtained in the present development.

6 shows a molecular arrangement of POSS, an organic / inorganic hybrid type nanomaterial according to the present invention, the size of the portion composed of covalent bonds of silicon and oxygen corresponding to the inorganic material is about 1.5 nm, and various kinds of these inorganic materials. The organic group of is covalently bonded. The inorganic part mainly serves to improve the thermal / mechanical properties, and the organic group contributes to the improvement of processability through compatibility with the base resin, uniform mixing, and lowering the mixing viscosity.

In the present invention, it is preferable to add the organic / inorganic hybrid nanomaterial in an amount of 0.1 to 15 parts by weight based on 100 parts by weight of the epoxy base, but when the content is out of the content, the toughness decreases, thereby maintaining the adhesive strength during cryogenic and thermal cycles. It is not desirable to have.

In addition, the cryogenic binder of the present invention may comprise a curing agent, a catalyst and other additives.

The curing agent is selected from the group consisting of poly (propylene oxide) diamine, diethylenetriamine, and hexamethylenediamine in the case of aliphatic amines; Aromatic amines are selected from the group consisting of diethyltoluene diamine, m-xylylene diamine, and meta-phenylene diamine; Acid anhydride is one or more selected from the group consisting of methylnadic anhydride and hexahydro-4-methylphthalic anhydride. It serves as a crosslinking agent to cure the epoxy resin which is a binder resin.

The content of the curing agent is 10 to 80 parts by weight in the case of aliphatic amine curing agent, 10 to 30 parts by weight in the case of aromatic amine, and 70 to 140 parts by weight in the case of acid anhydride curing agent based on 100 parts by weight of the epoxy resin. desirable.

In addition, the crosslinking reaction of the epoxy binder resin and the curing agent may include a catalyst that can accelerate the curing rate or promote the curing conditions, specifically, tertiary amine, imidazole, latent catalyst (latent accelerator) and the like have. The content of the catalyst is preferably 0.5 to 3 parts by weight based on 100 parts by weight of the epoxy base resin.

In addition, the binder of the present invention may include various other additives in addition to the above constituents in a range that does not impair the physical properties of the cryogenic binder of the present invention.

The binder according to the present invention may be prepared by adding a curing agent, POSS, a catalyst, and other additives of an organic / inorganic hybrid nanomaterial to the epoxy base resin and reacting at room temperature for 12-24 hours.

In the case of producing the epoxy-based cryogenic binder according to the present invention under the above conditions, the reaction rate is 95% or more for imparting toughness for maintaining adhesiveness at cryogenic temperatures and maintaining adhesiveness during thermal cycling, which are important in cryogenic binders. It is preferable at the point of view.

The binder of the present invention prepared as described above has excellent adhesion performance even at cryogenic conditions, preferably -197 ° C to room temperature, and is used in an adsorption panel bonded to an adsorbent in a cryogenic pump as a final purpose, and thermal cycling in the above temperature range. Even after the thermal shock generated in the process can maintain a strong adhesive force. Specifically, even when the thermal cycling is repeated at least 50 cycles at the above temperature, the adhesive strength with the metal panel can be maintained at 10 MPa or more, and the activated carbon has a property of maintaining strong adhesive strength even at the thermal shock of 50 cycles or more.

In addition, the glass transition temperature of the cryogenic binder of the present invention is preferably 40 to 50 ° C in view of imparting toughness for maintaining adhesion at cryogenic temperatures and maintaining adhesion during thermal cycling, which are important in cryogenic binders.

On the other hand, the present invention also has a feature to provide a cryogenic pump comprising an adsorption panel bonded to the binder prepared as described above with an adsorbent.

The manufacturing process of the adsorption panel according to the present invention is shown in FIG. 7. First, a substrate such as copper (Cu) plated with chromium (Cr) is manufactured using a method such as a press mold in a desired form. Next, the cryogenic binder according to the present invention prepared herein is spray coated. The thickness of the coated binder is preferably 0.2 to 0.7 mm, but is not particularly limited. In order to prevent the coated cryogenic binder resin from penetrating into the substrate, the cryogenic binder is first hardened to slightly increase the viscosity.

Next, active carbon for adsorbing hydrogen (H ₂ ), helium (He), and neon (Ne) is attached thereto. The activated carbon used at this time can be used, as shown in Figure 8, the particle size of 3 ~ 4mm / Φ, 2 ~ 3mm / Φ, 1 ~ 2mm / Φ, epoxy of the curing agent used It can be used depending on the type and degree of vacuum of the cryogenic vacuum pump. Second curing in an oven of appropriate temperature then results in a final adsorption panel. Secondary curing conditions are preferably run at 80-110 ° C. for 1-3 hours and at 140-160 ° C. for 30-60 minutes. Then, if each adsorption panel is mechanically assembled in several pieces as necessary, a set of adsorption panels can be obtained.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

Example 1

7 g of polyhedral oligomeric silsesquioxane (POSS) to 100 g of bisphenol-A diglycidyl ether having an equivalent weight of 175 g to 300 g, which is a bifunctional epoxy resin as the base resin, and a poly (propylene oxide) diamine as a curing agent. A binder was prepared by adding 60 g of (poly (propylene oxide) diamine). The copper substrate plated with chromium was manufactured in a desired form by using a press mold, and then the coated binder was spray-coated to a thickness of 0.3 mm, and then primarily cured at room temperature for 24 hours, and the particle size was 3 Adsorption panels were prepared by adhering activated carbon of ˜4 mm / Φ. This was cured for 2 hours at 100 ° C. for 1 hour and at 160 ° C. for 30 minutes, and then the adsorption panel set mechanically assembled was mounted on a cryogenic pump, a cryogenic vacuum pump. The reaction rate of the said binder resin was 95%.

Example 2

The cryogenic binder resin and the adsorption panel were manufactured in the same manner as in Example 1, except that the content of POSS was 10 parts by weight.

Example 3

Cryogenic binder in the same manner as in Example 1, except that di- (4-diglycidylaminophenyl) methane, which is a tetrafunctional epoxy resin, is used as the epoxy base resin. The resin and the adsorption panel were prepared.

Comparative Example 1

The cryogenic binder resin and the adsorption panel were prepared in the same manner as in Example 1, except that fumed silica was used instead of the used POSS.

Physical properties of the prepared binder resin were measured as follows, and the results are shown in Table 2 below.

1) Viscosity: 10 ml of a sample prepared using a Brookfield viscometer (LVDVII +, BROOKFIELD, USA) was placed in a small sample adapter and the viscosity was measured at 30 ° C.

2) Adhesion: The binder resin was measured according to a single lap shear test (ASTM D1002, Instron 4467, USA) before and after performing thermal cycling for 20 times at a temperature of −197 ° C. to room temperature.

3) Glass transition temperature (T _g ): Measured while raising the temperature at a rate of 10 ℃ / min using DSC.

Binder properties Initial viscosity
(30 ° C, cPs) Adhesive force (MPa) T _g (℃) Before thermal cycling After thermal cycling Before thermal cycling After thermal cycling Example 1 21,000 14 12 45 45 Example 2 23,000 14 11 48 48 Example 3 18,000 12 11 60 60 Comparative Example 1 30,000 12 8 45 45

As can be seen from the results of Table 2, in the case of adding the organic / inorganic hybrid nanomaterial in the preparation of the cryogenic binder as in the present invention before and after thermal cycling in comparison with Comparative Example 1 using the fumed silica as in the prior art It can be seen that the adhesion is better. In addition, as the organic / inorganic hybrid nanomaterials are added, compatibility with the base resin is improved, and thus an increase in initial viscosity is smaller than that of Comparative Example 1, thereby improving processability.

In addition, the adsorption panel to which the activated carbon was attached to the binder resin was thermally cycled 50 times at a temperature of −197 ° C. to room temperature, and then the degree of peeling between the activated carbon and the metal substrate and the metal substrate and the binder resin was visually observed.

In the case of using the binder prepared according to the embodiment of the present invention, no peeling occurred, but in the case of using the binder prepared according to Comparative Example 1, the peeling was already performed in 20 to 30 times of thermal cycling. From this, in the case of the binder according to the invention it was confirmed that even if the thermal cycling proceeds in a special situation of cryogenic temperature, the adhesive force is maintained as it is.

1 is a real picture of the cryo pump,

2 shows the principle / structure of the cryo pump,

Figure 3 shows the adsorption panel (15K-Cryopanel) of the cryo pump,

Figure 4 is a photograph of the adsorption material is desorbed from the adsorption panel of the cryo pump,

5 is a view showing the intermediate properties of the polymer of the POSS and the ceramic,

6 is a molecular arrangement of POSS,

7 is a manufacturing process of the adsorption panel and 15K-Cryopanel set assembly,

8 shows activated carbon for adsorption panel fabrication.

Claims (9)

Cryogenic binders containing epoxy resins and organic / inorganic hybrid nanomaterials. The cryogenic binder of claim 1, wherein the organic / inorganic hybrid nanomaterial is polyhedral oligomeric silsesquioxanes. The cryogenic binder according to claim 1, wherein the epoxy resin is at least one member selected from the group consisting of a bifunctional epoxy resin and a tetrafunctional epoxy resin. According to claim 3, wherein the bifunctional epoxy resin is equivalent to 175g to 300g, bisphenol-A diglycidyl ether (diglycidyl ether of bisphenol-A), bisphenol-F diglycidyl ether (diglycidyl ether of bisphenol F), and diglycidyl ether of biphenyl. The tetrafunctional epoxy resin is equivalent to 180g to 300g, di- (4-diglycidylaminophenyl) methane (di (4-diglycidylaminophenyl) methane), and tetraglycidyl meta-xylene diamine (tetraglycidyl meta cryogenic binder, characterized in that at least one member selected from the group consisting of -xylene diamine). The cryogenic binder according to claim 1, wherein the organic / inorganic hybrid nanomaterial is included in an amount of 0.1 to 15 parts by weight based on 100 parts by weight of the epoxy resin. The cryogenic binder of claim 1, wherein the cryogenic binder further comprises at least one member selected from the group consisting of a curing agent, a catalyst and other additives. The cryogenic binder according to claim 1, wherein the binder maintains an adhesive strength of 10 to 15 MPa even after thermal shock generated during a thermal cycling process at a temperature of −197 ° C. to room temperature. The cryogenic binder of claim 1, wherein the binder has an initial viscosity of 20,000-40,000 cPs and a glass transition temperature of 40 to 50 ° C. A cryogenic pump comprising an adsorption panel formed by adhering the cryogenic binder according to claim 1 with an adsorbent.

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