Method for producing resins useful in semiconductor manufacturing

Abstract

A method for making an ion exchange resin, the method comprising the steps of: (a) providing a basic ion exchange resin in an acidic form, the basic ion exchange resin containing amino polyol groups and swelling by 15-30% by volume upon conversion from the basic form to the acidic form; and (b) washing the resin with water or an aqueous acid solution.

Description

Technical Field

[0001] The present invention generally relates to a method for producing an ion exchange resin useful for the purification of water used in semiconductor manufacturing.

Background Art

[0002] In recent years, the trend in designing ultrapure water (UPW) has been towards reverse osmosis (RO) and electro-deionization (EDI). In this design, it is important to reduce boron to a very low level. Boron-selective ion exchange resins, such as resins functionalized with aminopolyols, are attractive options for this. However, the resin needs to be very pure, i.e., it needs to produce water with low total organic carbon (TOC) and high resistivity. Also, the resin needs to be physically stable and have a high capacity for removing boron. For example, Japanese Patent No. 4518112 discloses a method for reducing TOC in aminopolyol resins. However, this document teaches a method using harsh conditions that may affect other resin properties.

Summary of the Invention

Means for Solving the Problems

[0003] The present invention relates to a method for producing an ion exchange resin. The method includes (a) providing a basic ion exchange resin in an acidic form (the aforementioned resin contains an aminopolyol group and swells by 15 - 30% in volume percentage when converted from the basic form to the acidic form), and (b) washing the resin with water or an aqueous acid solution. and includes.

[0004] Furthermore, the present invention relates to an ion exchange resin containing 2 - 4 wt% of polymerization units of a crosslinking agent, a macroreticular structure, and 2.0 - 3.2 equivalents / kg of active sites (the aforementioned active sites contain aminopolyol functional groups).

Mode for Carrying Out the Invention

[0005] Unless otherwise specified, all percentages are weight percentages (weight%), and all temperatures are in °C. Unless otherwise specified, averages are arithmetic mean. Unless otherwise specified, all operations are performed at room temperature (18-25°C).

[0006] The polymerization, chloromethylation, and amination steps are designed to yield a final product with 15-30% swelling during the conversion from free base to acid form. This swelling is determined by crosslinking and the number and type of functional groups. There are three types of crosslinking: (i) crosslinking by copolymerization of the crosslinking agent with a styrene monomer, (ii) methylene bridging occurring during chloromethylation, and (iii) reaction of two chloromethyl groups of the amino polyol with the strong base group during amination. The degree of chloromethylation and amination is influenced by the relative number of different functional groups.

[0007] "Styrene monomers" include monoethylene unsaturated aromatic compounds, such as styrene, vinyltoluene, ethylvinylbenzene, chlorostyrene, and vinylnaphthalene. "Styrene crosslinking agents" include polyvalent ethylenically unsaturated aromatic compounds such as divinylbenzene and trivinylbenzene. Other monoethylene unsaturated compounds, preferably less than 10% by weight (preferably less than 5% by weight), can be added to improve the product, such as strength, for example, methacrylic acid and its esters, vinylpyridine, acrylonitrile, vinyl ethers, esters, and ketones. In addition, polyvalent ethylenically unsaturated aromatic compounds can be used as crosslinking agents, preferably such as trivinylcyclohexane and di and trimethacrylate compounds such as trimethylolpropane trimethacrylate. The percentage of monomer units in the polymer is based on the total weight (dry weight) of the polymer. The term "gel" resin applies to resins synthesized from copolymers with very low porosity (0–0.1 cm³ / g), small average pore size (0–17 Å), and low BET surface area (0–10 m² / g). The term "macro-network" (or MR) resin applies to resins synthesized from highly mesoporous copolymers with a larger surface area than gel resins. MR resins have a total porosity of 0.1–0.7 cm³ / g, an average pore size of 17–500 Å, and a BET surface area of ​​10–200 m² / g. MR resins are typically produced by incorporating organic solvents ("pologens") into monomer mixtures. The term "adsorbent resin" applies to resins with very high surface area and porosity, regardless of whether they can be functionalized. These adsorbents have a surface area of ​​200–1300 m² / g, an average pore size of 17–1000 Å, and a total porosity of 0.7–200 cm³ / g.

[0008] The harmonic mean diameter (HMD) is given by the following formula:

number

[0009] The method of the present invention preferably uses a basic ion exchange resin containing 2 to 4% by weight of crosslinking agent polymerization units, a macro-network structure, and 2.0 to 3.2 equivalents / kg of active sites (the aforementioned active sites include amino polyol functional groups). The active sites are amino groups and quaternary ammonium groups.

[0010] Preferably, the crosslinking agent has two polymerizable carbon-carbon double bonds per molecule. Preferably, the crosslinking agent has a molecular weight of 100 to 400, preferably 100 to 250, and preferably 120 to 200. Preferably, the resin contains 2.5 to 3.5% by weight of crosslinking agent polymerization units. Preferably, the resin contains 96 to 98% by weight, preferably 96.5 to 97.5% by weight of styrene monomers. Preferably, the crosslinking agent is divinylbenzene. Preferably, the resin contains 96 to 98% by weight of styrene polymerization units and 2 to 4% by weight of divinylbenzene polymerization units, preferably 96.5 to 97.5% by weight of styrene polymerization units and 2.5 to 3.5% by weight of divinylbenzene polymerization units.

[0011] Preferably, the copolymer is chloromethylated under conditions that preferably give 90-100% substitution of the styrene monomer. Chloromethylation is carried out under conditions that minimize methylene bridging, which may reduce swelling. The crosslinked chloromethylated styrene polymer is then aminated with an aminopolyol, preferably N-methylglucamine. Preferably, after amination, the resin contains 2.0-3.2 equivalents / kg of active sites, preferably at least 2.3 equivalents / kg, preferably at least 2.5 equivalents / kg, preferably 3.1 equivalents / kg or less, preferably 3.0 equivalents / kg or less, and preferably 2.5-3.0 equivalents / kg of aminopolyol groups.

[0012] Preferably, the aminopolyol group contains 3 to 9 carbon atoms, preferably at least 4, preferably at least 5, preferably at least 6, preferably 8 or fewer, and preferably 7 or fewer. Preferably, the aminopolyol group contains 2 to 8 hydroxyl groups, preferably at least 3, preferably at least 4, preferably at least 5, preferably 7 or fewer, and preferably 6 or fewer. Preferably, the aminopolyol group has 7 carbon atoms and 5 hydroxyl groups. N-methylglucamine is particularly preferred. The aminopolyol group in the resin is produced by reacting a chloromethylated crosslinked polymer containing polymerization units of styrene monomers with an aminopolyol. The aminopolyol is bonded to one or two benzene rings by a nitrogen-carbon bond between an amino nitrogen and a methylene group bonded to a benzene ring, as exemplified below for N-methylglucamine and crosslinked polystyrene. [ka]

[0013] When the aminopolyol N-methylglucamine is bonded to two benzene rings, the nitrogen is part of the quaternary amine (strong base) group. This crosslinks the polymer and reduces swelling. Preferably, the resin after the amination process has 0-30% strong base, preferably 5-20% strong base, and preferably 5-10% strong base, based on the total basicity site.

[0014] Acidic basic ion exchange resins are prepared by adding an acidic aqueous solution to a resin in its basic form and immersing the resin. Preferably, the acid immersion is repeated at least once. The conditions for acid treatment of ion exchange resins are well known. Washing with water or an acidic aqueous solution after acid treatment is carried out according to a known process. Preferably, the resin is washed with deionized water of at least 20 BV, preferably at least 40 BV, and preferably at least 60 BV. Preferably, the temperature of the deionized water is 50°C to 100°C, preferably 50°C to 85°C (the disappearance of strong bases may exceed 85°C), preferably 75°C to 85°C. Preferably, water is used as the washing agent. When an acidic aqueous solution is used, the acid concentration is preferably less than 10% by weight, preferably less than 5% by weight, and preferably less than 1% by weight. Preferably, the resin is returned to its basic form for use by contacting it with a saline aqueous solution under known conditions.

[0015] Preferably, the ion exchange resin particles have a harmonic mean diameter of 100 to 1500 μm, preferably at least 300 μm, preferably at least 400 μm, preferably 1000 μm or less, preferably 700 μm or less, and preferably 600 μm or less. [Examples]

[0016] Abbreviations used: DI = deionization, BV = bed volume, TOC = total organic carbon, MHC = moisture content, WC = gravimetric volume (equivalent active sites / kg), VC = volumetric volume per liter, SB = strong base (equivalent of strong base / total equivalent (strong base and weak base)).

[0017] Best Practice - Example 1 (Washing at 80°C after acid treatment) Seven liters of Dowex® BSR-1 chelate resin were added to a 1.5-gallon container. The resin was measured to have a 22% swelling (from OH to Cl). 2.7 liters of 4% by weight hydrochloric acid were added. 3. After soaking for 30 minutes, the liquid was removed using a siphon. 4. Processes 2 and 3 were repeated twice (total 21 liters of hydrochloric acid). 5. 5.7 liters of DI water was added. 6. It was immersed for 20 minutes and the liquid was removed by siphon. 7. Processes 2 and 3 were repeated twice (total 21 liters of DI water). 8. Processes 1 - 7 were repeated to produce 14 liters of hydrochloric acid - treated BSR - 1 resin. 9. A 20 - liter glass column (diameter 5.5) was filled with 14 liters of hydrochloric acid - treated BSR - 1 resin. 10. DI water at 80 °C was passed through the column in a downward flow at 6.6 BV / hour (1540 ml / min) for 13 hours. 11. DI water at ambient temperature was passed through the column in a downward flow at 6.6 BV / hour (1540 ml / min) for 13 hours. 12. 21 liters of 4% sodium hydroxide was passed through the column at 350 ml / min for 60 minutes. 13. The flow was stopped and the resin was immersed in 4% sodium hydroxide for 30 minutes. 14. Processes 12 and 13 were repeated. 15. DI water at ambient temperature was passed through the column in a downward flow at 6.6 BV / hour (1540 ml / min) for 6.5 hours. 16. It was siphoned (packout) and dehydrated.

[0018] The final resin was analyzed for baseline delta - TOC and resistivity using Anatel A - 1000 at 50 BV / hour. The baseline delta - TOC was rinsed to 2.0 - 2.1 ppb and the resistivity was rinsed to 18.1 M ohm - cm. Before the above cleaning, the static boron capacity was measured to be 3.8 g - boron / kg resin. After cleaning, the static boron capacity was measured to be 3.5 g - boron / kg resin (92% of the original capacity).

[0019] The specified characteristics were not affected by the cleaning process.

Table 1

[0020] Comparison - Example 2 (PWA10 using cross-treatment) 1. 500 ml of Amberlite® PWA10 was added to a beaker. The resin was measured to have a 7% swelling (from OH to HCl). 2,500 ml of MilliQ water was added and the mixture was left to soak overnight. 3. The liquid was removed using a siphon. 4,500 ml of 1N hydrochloric acid was added. Contact was allowed for 30 seconds. 5. The liquid was removed using a siphon. 6. Repeat steps 3-4. 7. The resin was transferred to the glass column. 8.1N hydrochloric acid was passed through the resin at ambient temperature at a rate of 4 BV / hour (33 ml / min) for 1.4 hours. 9. MilliQ water was passed through the resin at ambient temperature at 4 BV / hour (33 ml / min) for 1.0 hour. 10.1N sodium hydroxide was passed through the resin at ambient temperature at a rate of 4 BV / hour (33 ml / min) for 1.3 hours. 11. MilliQ water was passed through the resin at ambient temperature at 4 BV / hour (33 ml / min) for 1.0 hour. 12. Repeat steps 10-11.

[0021] The final resin was analyzed for baseline delta-TOC and resistivity using an Anatel A-1000 at 25 BV / hour. Baseline delta-TOC was rinsed to 34.5 ppb, and resistivity was rinsed to 18.2 M ohms-cm.

[0022] Comparison - Example 3 (BSR-1 using cross-processing) 1. 500 ml of Dowex® BSR-1 chelate resin was added to a beaker. The resin was measured to have a 22% swelling (from OH to Cl). 2,500 ml of MilliQ water was added and the mixture was left to soak overnight. 3. The liquid was removed using a siphon. 4,500 ml of 1N hydrochloric acid was added. Contact was allowed for 30 seconds. 5. The liquid was removed using a siphon. 6. Repeat steps 3-4. 7. The resin was transferred to the glass column. 8.1N hydrochloric acid was passed through the resin at ambient temperature at a rate of 4 BV / hour (33 ml / min) for 1.4 hours. 9. MilliQ water was passed through the resin at ambient temperature at 4 BV / hour (33 ml / min) for 1.0 hour. 10.1N sodium hydroxide was passed through the resin at ambient temperature at a rate of 4 BV / hour (33 ml / min) for 1.3 hours. 11. MilliQ water was passed through the resin at ambient temperature at 4 BV / hour (33 ml / min) for 1.0 hour. 12. Repeat steps 10-11.

[0023] The final resin was analyzed for baseline delta-TOC and resistivity using an Anatel A-1000 at 25 BV / hour. Baseline delta-TOC was rinsed down to 9.8 ppb, and baseline resistivity was rinsed down to 18.2 M ohms-cm.

[0024] Comparison - Example 4 (PWA10 washed at 90°C) - PAC-BSR-11 1. A 2-inch diameter jacketed glass column was filled with 150 ml of Amberlite® PWA10. DI water at 2.90°C was passed through the column in a downward flow at 6.6 BV / hour (16 ml / min) for 6.5 hours. 3. DI water at ambient temperature was passed through the column in a downward flow at 13 BV / hr (33 ml / min) for 1.9 hours. 4. The meat was drained and dehydrated using a siphon.

[0025] The final resin was analyzed for baseline delta-TOC and resistivity using an Anatel A-1000 at 50 BV / hour. The baseline delta-TOC was rinsed to 2.5 ppb, and the baseline resistivity was rinsed to 17.7 M ohms-cm. Before the above washing, the static boron capacity was measured at 4.2 g-boron / L-resin. After washing, the static boron capacity was measured at 3.2 g-boron / L-resin (77% of the original capacity). This washing process changed the percentage of strong base from 34.5% to 13.9%.

[0026] [Table 2]

Claims

1. (a) A step of providing an acidic basic ion exchange resin prepared by adding an acidic aqueous solution to a basic resin and immersing the resin, wherein the resin contains amino polyol groups and swells by 15-30% by volume when converted from basic to acidic form, (b) A step of washing the resin with water, (c) A step of returning the resin to the basic form by contacting it with a saline solution, A method for producing an ion exchange resin, comprising: The aforementioned resin has a macro-network structure, The water used in process (b) is deionized water at a temperature of 50°C to 100°C. A method characterized by the following:

2. The method according to claim 1, wherein the resin contains 2.0 to 3.2 equivalents / kg of active sites.

3. The method according to claim 1, wherein the resin contains 2.5 to 3 equivalents / kg of aminopolyol groups.

4. The method according to claim 1, wherein the resin contains 2 to 4% by weight of a crosslinking agent polymerization unit.

5. The method according to claim 1, wherein the water in step (b) is deionized water at a temperature of 50°C to 85°C.

6. The method according to claim 1, wherein the resin comprises 96 to 98% by weight of a styrene monomer.

7. The method according to claim 1, wherein the amino polyol is N-methylglucamine.

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