Process for preparing sorptive substrates

Patent metadata

Field	Value
Publication number	US-9884351-B2
Application number	US-201514599740-A
Country	US
Kind code	B2
Filing date	Jan 19, 2015
Priority date	Aug 1, 2011
Publication date	Feb 6, 2018
Grant date	Feb 6, 2018

Abstract

A process for treating a substrate comprised of sorptive material is provided herein. The sorptive material may be an absorbent synthetic material such as polyester. The material is designed to be used for cleaning surfaces in an ultraclean environment. The process first comprises unwinding a roll of sorptive material as a substrate into a cleaning system. The cleaning system utilizes several sections. These include a pre-washing section, an acoustic energy washing section, and a drying section. Preferably, the process of moving the substrate through the cleaning system is continuous. The acoustic energy washing section employs one or more acoustic energy generators. In one aspect, the process also includes cutting the substrate into sections to form wipers after moving the substrate through the drying section. Thereafter, the wipers are placed into a bag and the bag is sealed.

First claim

We claim:

1. A process for treating a sorptive material, comprising:
unwinding a roll of sorptive material as a substrate into a cleaning system, the roll being between about 4 inches (10.16 cm) and 18 inches (45.72 cm) in width;
moving the substrate through an acoustic energy washing section in the cleaning system, wherein each of a front side and a back side of the substrate are directly exposed to energy pulses from acoustic energy generators within a tank of a washing solution, with at least one of the acoustic energy generators in the acoustic energy washing section being a tubular resonator that operates at a frequency of between about 20 and 80 kHz, thereby producing a cleaned sorptive material for use in wiping surfaces in a cleanroom environment; and
further moving the substrate through a drying section in the cleaning system, wherein HEPA-filtered and heated air is applied to product a cleaned and dried sorptive material; and
wherein the cleaned and dried sorptive material uniformly has less than 150 contaminant fibers per square meter that are greater than 100 μm in length.

2. The process of claim 1 , wherein the sorptive material comprises a synthetic material.

3. The process of claim 2 , wherein the sorptive material comprises primarily polyester.

4. The process of claim 1 , wherein the sorptive material is an absorbent material.

5. The process of claim 4 , wherein the absorbent material has an absorbency of between about 300 mL/m 2 to 650 mL/m 2 .

6. The process of claim 2 , further comprising:
moving the substrate through a pre-washing section in the cleaning system, wherein a prepping fluid is sprayed onto the sorptive material before moving the substrate through the acoustic energy washing section.

7. The process of claim 6 , wherein:
the prepping fluid in the pre-washing section (i) is a liquid that comprises primarily deionized water, (ii) is a gaseous fluid comprising carbon dioxide, steam, ozone, or mixtures thereof, or (iii) combinations thereof;
the substrate moves through a series of rollers above a fluid container in the pre-washing section; and
the prepping fluid is sprayed onto both the front and back sides of the substrate.

8. The process of claim 7 , wherein moving the substrate through the pre-washing section, the acoustic energy washing section, and the drying section is continuous.

9. The process of claim 8 , further comprising:
after moving the substrate through the drying section, cutting the substrate into sections to form individual wipers;
placing the wipers into a bag; and
sealing the bag.

10. The process of claim 9 , wherein cutting of the substrate into sections and placing wipers into the bag are substantially performed without a human hand touching the sorptive material.

11. The process of claim 10 , wherein the cutting the substrate into sections is performed by using a laser cutter, a sonic knife, or a sonic horn.

12. The process of claim 9 , wherein each wiper only has between about (i) 30,000 and 70,000 contaminant fibers per square meter that are between about 5.0 and 100 μm in length, (ii) 0.5×10 6 and 5.0×10 6 contaminant fibers per square meter that are between about 0.5 and 5.0 μm in length, or (iii) both.

13. The process of claim 9 , wherein each wiper has less than about 0.06 ppm potassium, less than about 0.05 ppm chloride, less than about 0.05 ppm magnesium, less than about 0.20 ppm calcium, and less than about 0.30 ppm sodium.

14. The process of claim 6 , wherein:
the acoustic energy washing section comprises a first acoustic energy washer having the tank as a first tank through which the substrate is moved during cleaning, with the first tank holding a volume of deionized water and surfactant;
the first acoustic energy washer has a first set of rollers for guiding the substrate around a first transducer such that the front side of the substrate is directly exposed to ultrasonic energy from the first transducer;
the first acoustic energy washer also has a second set of rollers for guiding the substrate around a second transducer such that the back side of the substrate is also directly exposed to ultrasonic energy from the second transducer; and
the first tank further holds the tubular resonator as either the first or the second transducer.

15. The process of claim 14 , wherein:
the acoustic energy washing section further comprises a second acoustic energy washer, the second acoustic energy washer comprising a second tank holding a volume of deionized water and surfactant, through which the substrate is also moved during cleaning;
the substrate passes across two or more rollers submerged within the second tank; and
at least one of the acoustic energy generators in the washing section also comprises a megasonic transducer within the second tank that operates at a frequency of between about 900 kHz and 2.0 MHz.

16. The process of claim 6 , wherein the acoustic energy washing section comprises:
an ultrasonic energy washing station having the tubular resonator, operating at a frequency of between about 20 kHz and 50 kHz;
a tank in the ultrasonic energy washing station for holding a volume of deionized water and surfactant while the substrate is moved through the ultrasonic energy washing station, wherein the substrate moves into the tank while passing through the ultrasonic energy washing station;
a megasonic energy washing station having at least one acoustic transducer operating at a frequency of between about 900 kHz and 2.0 MHz; and
a separate tank in the megasonic energy washing station for holding a volume of deionized water and surfactant while the substrate is moved through the ultrasonic energy washing station, wherein the substrate moves into the separate tank while passing through the ultrasonic energy washing station.

17. The process of claim 3 , further comprising:
before moving the substrate through the drying section, moving the substrate through a rinsing section, wherein the substrate is rinsed with an aqueous solution comprising primarily deionized water.

18. The process of claim 6 , further comprising:
placing the roll of sorptive material onto a shaft; and
wherein unwinding the roll of sorptive material comprises unwinding the roll from the shaft in order to introduce the substrate to the pre-washing section.

19. The process of claim 18 , wherein:
the roll of sorptive material is wound around a core before being placed onto the shaft;
the roll of sorptive material has a length of at least 25 feet (3.31 meters) before being placed onto the shaft; and
unwinding the roll of sorptive material comprises rotating the shaft.

20. A method of cleaning a surface, comprising:
receiving a package of wipers, with each wiper uniformly having less than 150 contaminant fibers per square meter that are greater than 100 μm in length, and the wipers having been packaged in a processing system comprising:
an acoustic energy washing section configured to expose a front side and a back side of a substrate to energy pulses from one or more acoustic energy generators within a tank of a washing solution,
a rinsing section after the acoustic energy washing section, wherein the substrate is rinsed with an aqueous solution comprising primarily deionized water to produce a cleaned substrate;
a drying section configured to apply warmed and HEPA-filtered air to the cleaned substrate,
a cutting section configured to continuously cut the substrate into individual wipers after the substrate has passed through the drying section, an

Assignees

• Illinois Tool Works

Inventors

• Blaiss H Dennis
• Sene Laurent H
• Hall Gregory T
• Whittington Randy H

Classifications

• B08B7/028 Primary

  Using ultrasounds · CPC title

• A47L13/17 Primary

  containing cleaning agents (A47L13/19 takes precedence {; chemical compositions C11D17/049}) · CPC title

• B08B1/02

  Operations & Transport · mapped topic

• B08B1/006

  Operations & Transport · mapped topic

• D06B21/00

  Successive treatments of textile materials by liquids, gases or vapours · CPC title