Method for producing resin useful in semiconductor manufacturing

Abstract

To provide a method for producing an ion exchange resin.SOLUTION: The method comprises steps of: (a) providing a basic ion exchange resin in the acidic form which comprises amino polyol groups and has a volume percentage swelling by 15-30% upon conversion from the basic form to the acidic form; and (b) washing the resin with water or an acid aqueous solution.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates generally to a method for making ion exchange resins useful in purifying water used in semiconductor manufacturing. [Background technology]

[0002] In recent years, the trend in designing ultrapure water (UPW) has been towards reverse osmosis (RO) and electrodeionization (EDI). In this design, it is important to reduce boron to very low levels. Boron-selective ion exchange resins, such as those functionalized with aminopolyols, are an attractive option for this. However, the resins need to be very pure, i.e., produce water with low total organic carbon (TOC) and high resistivity. They also need to be physically stable and have a high capacity to remove boron. For example, Japanese Patent Publication 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 problem]

[0003] The present invention relates to a method for making an ion exchange resin, the method comprising: (a) providing a basic ion exchange resin in an acidic form, said resin containing amino polyol groups and swelling by 15-30% by volume upon conversion from the basic form to the acidic form; (b) washing the resin with water or an aqueous acid solution; Includes.

[0004] Further, the present invention relates to an ion exchange resin comprising 2-4 wt. % of polymerized units of a crosslinker, a macroreticular structure and 2.0-3.2 equivalents / kg of active sites, said active sites comprising aminopolyol functional groups. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0006] The polymerization, chloromethylation, and amination steps are designed to give a final product that has 15-30% swelling upon conversion from the free base to the acid form. This swelling is determined by crosslinking and by the number and type of functional groups. There are three types of crosslinking: (i) crosslinking by copolymerization of the crosslinker with styrenic monomers, (ii) methylene bridging, which occurs in chloromethylation, and (iii) reaction of the aminopolyol with two chloromethyl groups (groups of a strong base) in amination. The degree of chloromethylation and amination affects the relative number of different functional groups.

[0007] "Styrenic monomers" include monoethylenically unsaturated aromatic compounds, such as styrene, vinyl toluene, ethyl vinyl benzene, chlorostyrene, and vinyl naphthalene. "Styrenic crosslinkers" include polyethylenically unsaturated aromatic compounds, such as divinyl benzene and trivinyl benzene. Other monoethylenically unsaturated compounds can be added, preferably in amounts less than 10% by weight (preferably less than 5% by weight), for product improvement, such as strength, such as, for example, methacrylic acid and its esters, vinyl pyridine, acrylonitrile, vinyl ethers, esters, and ketones. Polyethylenically unsaturated aromatic compounds can also be used as crosslinkers, preferably, for example, trivinyl cyclohexane, and di- and trimethacrylate compounds, such as trimethylolpropane trimethacrylate. The percentage of monomer units in the polymer is based on the total polymer weight (dry weight). The term "gel" resins is applied 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 "macrotreticular" (or MR) resins is applied to resins synthesized from highly mesoporous copolymers with higher surface area than gel resins. MR resins have total porosity of 0.1-0.7 cm3 / g, average pore size of 17-500 Å, and BET surface area of ​​10-200 m2 / g. MR resins are typically made by incorporating an organic solvent ("porogen") into the monomer mixture. The term adsorbent resins is applied to resins with very high surface area and porosity, whether or not they can be functionalized. These adsorbents have surface areas of 200-1300 m2 / g, average pore size of 17-1000 Å, and total porosity of 0.7-200 cm3 / g.

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

number

[0009] The method of the present invention preferably uses a basic ion exchange resin containing 2-4% by weight of polymerized units of a crosslinker, a macroreticular structure, and 2.0-3.2 equivalents / kg of active sites, said active sites including aminopolyol 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 100-400, preferably 100-250, preferably 120-200. Preferably, the resin comprises 2.5-3.5% by weight of polymerized units of the crosslinking agent. Preferably, the resin comprises 96-98% by weight, preferably 96.5-97.5% by weight of a styrene-based monomer. Preferably, the crosslinking agent is divinylbenzene. Preferably, the resin comprises 96-98% by weight of polymerized units of styrene and 2-4% by weight of polymerized units of divinylbenzene, preferably 96.5-97.5% by weight of polymerized units of styrene and 2.5-3.5% by weight of polymerized units of divinylbenzene.

[0011] Preferably, the copolymer is chloromethylated, preferably under conditions that give 90-100% substitution of the styrenic monomer. The chloromethylation is carried out under conditions that minimize methylene bridging that may reduce swelling. The crosslinked chloromethylated styrenic 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 of active sites, preferably at least 2.5 equivalents / kg of active sites, preferably 3.1 equivalents / kg or less of active sites, preferably 3.0 equivalents / kg or less of active sites, 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 not more than 8, preferably not more than 7 carbon atoms. Preferably, the aminopolyol group contains 2 to 8 hydroxyl groups, preferably at least 3, preferably at least 4, preferably at least 5, preferably not more than 7, preferably not more than 6 hydroxyl groups. 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 polymerized units of a styrene-based monomer with an aminopolyol. The aminopolyol is attached to one or two benzene rings by a nitrogen-carbon bond between the amino nitrogen and a methylene group attached to the benzene ring, as exemplified below for N-methylglucamine and crosslinked polystyrene. [ka]

[0013] When the aminopolyol N-methylglucamine is attached to two benzene rings, the nitrogen is part of a 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, preferably 5-10% strong base, based on total basic sites.

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

[0015] Preferably, the ion exchange resin particles have a harmonic mean diameter of from 100 to 1500 μm, preferably at least 300 μm, preferably at least 400 μm, preferably not more than 1000 μm, preferably not more than 700 μm, preferably not more than 600 μm. EXAMPLES

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

[0017] Best Practice - Example 1 (wash at 80°C after acid treatment) To a 1.5 gallon container was added 7 liters of Dowex™ BSR-1 chelating resin. The resin was determined to have a 22% swell (OH to Cl). 2.7 liters of 4% by weight hydrochloric acid was added. 3.Steep for 30 minutes and then siphon off the liquid. 4. Steps 2 and 3 were repeated twice (total of 21 liters of hydrochloric acid). 5.7 liters of DI water was added. 6.Steep for 20 minutes and then siphon off the liquid. 7. Steps 2 and 3 were repeated twice (total of 21 liters of DI water). 8. Steps 1-7 were repeated to produce a total of 14 liters of hydrochloric acid treated BSR-1 resin. A 9.20 L glass column (diameter 5.5) was packed with 14 L 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 / hr (1540 ml / min) for 13 hours. 11. Ambient temperature DI water was passed through the column in a downward flow at 6.6 BV / hr (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 soaked in 4% sodium hydroxide for 30 minutes. 14. Steps 12 and 13 were repeated. 15. Ambient temperature DI water was passed through the column in a downward flow at 6.6 BV / hr (1540 ml / min) for 6.5 hours. 16. Siphon and pack out the water.

[0018] The final resin was analyzed for baseline delta-TOC and resistivity using an Anatel A-1000 at 50 BV / hr. The baseline delta-TOC was rinsed to 2.0-2.1 ppb and the resistivity was rinsed to 18.1 Mohm-cm. Prior to 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 given properties were not affected by the cleaning process. [Table 1]

[0020] Comparison - Example 2 (PWA10 with cross treatment) 1. 500ml of Amberlite™ PWA 10 was added to a beaker. The resin was measured to have 7% swell (OH to HCl). Add 2.500ml of MilliQ water and soak overnight. 3. The liquid was removed using a siphon. 4. 500 ml of 1N hydrochloric acid was added. The mixture was left in contact for 30 seconds. 5. The liquid was removed using a siphon. 6. Repeat steps 3 and 4. 7. The resin was transferred to a glass column. 8.1N hydrochloric acid was passed through the resin at ambient temperature at 4 BV / hr (33 ml / min) for 1.4 hours. 9. MilliQ water was passed through the resin at 4 BV / hr (33 ml / min) for 1.0 hour at ambient temperature. 10.1N sodium hydroxide was passed through the resin at ambient temperature at 4 BV / hr (33 ml / min) for 1.3 hours. 11. MilliQ water was passed through the resin at ambient temperature at 4 BV / hr (33 ml / min) for 1.0 hour. 12. Repeat steps 10 to 11.

[0021] The final resin was analyzed for baseline delta-TOC and resistivity using an Anatel A-1000 at 25 BV / hr. Baseline delta-TOC was run to 34.5 ppb and resistivity was run to 18.2 Mohm-cm.

[0022] Comparison - Example 3 (BSR-1 with crossover treatment) 1. 500 ml of Dowex™ BSR-1 chelating resin was added to a beaker. The resin was determined to have a 22% swell (OH to Cl). Add 2.500ml of MilliQ water and soak overnight. 3. The liquid was removed using a siphon. 4. 500 ml of 1N hydrochloric acid was added. The mixture was left in contact for 30 seconds. 5. The liquid was removed using a siphon. 6. Repeat steps 3 and 4. 7. The resin was transferred to a glass column. 8.1N hydrochloric acid was passed through the resin at ambient temperature at 4 BV / hr (33 ml / min) for 1.4 hours. 9. MilliQ water was passed through the resin at 4 BV / hr (33 ml / min) for 1.0 hour at ambient temperature. 10.1N sodium hydroxide was passed through the resin at ambient temperature at 4 BV / hr (33 ml / min) for 1.3 hours. 11. MilliQ water was passed through the resin at ambient temperature at 4 BV / hr (33 ml / min) for 1.0 hour. 12. Repeat steps 10 to 11.

[0023] The final resin was analyzed for baseline delta-TOC and resistivity using an Anatel A-1000 at 25 BV / hr. Baseline delta-TOC was run to 9.8 ppb and baseline resistivity was run to 18.2 Mohm-cm.

[0024] Comparison - Example 4 (PWA10 washed at 90°C) - PAC-BSR-11 1. A 2 inch diameter jacketed glass column was packed with 150 ml of Amberlite™ PWA10. 2. DI water at 90° C. was passed through the column in a downward flow at 6.6 BV / hr (16 ml / min) for 6.5 hours. 3. Ambient temperature DI water was passed through the column in a downward flow at 13 BV / hr (33 ml / min) for 1.9 hours. 4. Siphon and dehydrate.

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

[0026] [Table 2]

Claims

1. (a) providing a basic ion exchange resin in an acidic form, the resin containing amino polyol groups and swelling 15-30% by volume upon conversion from the basic form to the acidic form; (b) washing the resin with water or an aqueous acid solution; 1. A method for making an ion exchange resin comprising:

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

3. The method of claim 2 , wherein the resin has a macro-reticular structure.

4. The method of claim 3, wherein the resin comprises 2.5 to 3 equivalents / kg of amino polyol groups.

5. The method of claim 4, wherein the resin comprises 2-4 weight percent polymerized units of a crosslinker.

6. (a) providing a basic ion exchange resin in acidic form, said resin comprising 2-4 wt. % polymerized units of a crosslinker, a macroreticular structure, and 2.0-3.2 equivalents / kg of active sites, said active sites comprising amino polyol functional groups; (b) washing the resin with water or an aqueous acid solution; 1. A method for making an ion exchange resin comprising:

7. The method of claim 6, wherein the resin comprises 2.5 to 3 equivalents / kg of amino polyol groups.

8. The method of claim 7, wherein the resin comprises 96 to 98 weight percent styrenic monomers.

9. An ion exchange resin comprising 2-4 weight percent polymerized units of divinylbenzene, a macroreticular structure, and 2.0-3.2 equivalents / kg of active sites, the active sites comprising aminopolyol functional groups.

10. The ion exchange resin of claim 9 comprising 96 to 98 weight percent styrene monomer.

11. The ion exchange resin of claim 10, wherein the amino polyol is N-methylglucamine.

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