ANTI-STATIC AGENT FOR GLASS FIBER INSULATION

Abstract

A composition includes glass fibers and a polyether antistatic agent. The polyether antistatic agent has a molecular weight of less than about 2000, or less than about 1000. Exemplary polyether antistatic agents include polyethylene glycol, polypropylene glycol, a glycerol polyether, and combinations thereof. The polyether antistatic agent has a viscosity of less than about 600 cSt at 75 F., or less than about 200 cSt at 75 F. The composition may further include a solvent for the polyether antistatic agent; the solvent may include one or more organic soluble electrolytes, water or a combination thereof. Exemplary organic soluble electrolytes include calcium acetate, lithium acetate, an amine acetate, sodium benzoate, and combinations thereof. The composition may be used in various insulation applications, including in an insulation batt, insulation roll, insulation board, insulation pipe or unbonded glass fiber insulation. Methods for making glass fibers for use in insulation and methods for installing unbonded glass fiber insulation are also described.

Claims

1. A fiber composition comprising: bound or unbound glass fibers; a polyether antistatic agent; and a dedusting agent.

2. The fiber composition of claim 1, wherein the polyether antistatic agent includes at least one compound selected from the group consisting of polyethylene glycol, polypropylene glycol, and glycerol polyethers.

3. The fiber composition of claim 1, wherein the polyether antistatic agent has a molecular weight of less than 2000 g/mol.

4. The fiber composition of claim 1, wherein the polyether antistatic agent has a molecular weight of less than 1000 g/mol.

5. The fiber composition of claim 1, wherein the polyether antistatic agent has a viscosity of less than 600 cSt at 75 F.

6. The fiber composition of claim 1, wherein the polyether antistatic agent has a viscosity of less than 200 cSt at 75 F.

7. The fiber composition of claim 1, wherein the dedusting agent comprises a mineral oil.

8. The fiber composition of claim 1, wherein the dedusting agent comprises less than 0.5 wt. % of the weight of the fiber composition.

9. The fiber composition of claim 1, wherein the dedusting agent comprises less than 0.3 wt. % of the weight of the fiber composition.

10. The fiber composition of claim 1, wherein the fiber composition comprises bound glass fibers finished into a fiberglass batt or fiberglass roll.

11. The fiber composition of claim 1, wherein the fiber composition comprises unbound glass fibers used as blown insulation.

12. A method of making a fiber composition, the method comprising: forming glass filaments; cutting the glass filaments into glass fibers; and finishing the glass fibers into the fiber composition, wherein a polyether antistatic agent and a dedusting agent are applied to the glass filaments or the glass fibers during the making of the fiber composition.

13. The method of claim 12, wherein the polyether antistatic agent comprises a neat liquid of a polyether compound selected from the group consisting of polyethylene glycol, polypropylene glycol, and glycerol polyethers.

14. The method of claim 12, wherein the polyether antistatic agent comprises a solution comprising a polyether compound in a solvent.

15. The method of claim 14, wherein the solvent is water.

16. The method of claim 14, wherein the polyether antistatic agent solution further comprises at least one compound selected from the group consisting sodium benzoate, calcium acetate, lithium acetate, and an amine acetate.

17. The method of claim 12, wherein the polyether antistatic agent is applied to the glass filaments before they are cut into the glass fibers.

18. The method of claim 12, wherein the polyether antistatic agent is applied to the glass fibers before they are finished into the fiber composition.

19. The method of claim 12, wherein the dedusting agent comprises a mineral oil.

20. The method of claim 12, wherein the dedusting agent comprises less than 0.5 wt. % of the weight of the fiber composition.

21. The method of claim 12, wherein the dedusting agent comprises less than 0.3 wt. % of the weight of the fiber composition.

22. The method of claim 12, wherein the fiber composition is a fiberglass insulation batt or fiberglass insulation roll.

23. The method of claim 12, wherein the fiber composition is blown fiberglass

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] A further understanding of the nature and advantages of the present invention may be realized by reference to the remaining portions of the specification and the drawings wherein like reference numerals are used throughout the several drawings to refer to similar components. In some instances, a sublabel is associated with a reference numeral and follows a hyphen to denote one of multiple similar components. When reference is made to a reference numeral without specification to an existing sublabel, it is intended to refer to all such multiple similar components.

[0026] FIG. 1 is a flowchart showing selected steps in a method of making bonded glass fiber insulation according to embodiments of the invention.

[0027] FIG. 2 is a flowchart showing selected steps in a method of making a unbonded glass fiber insulation according to embodiments of the invention.

[0028] FIG. 3 is a flowchart showing selected steps in a method of applying unbonded glass fiber insulation to a surface to be treated according to embodiments of the invention.

DETAILED DESCRIPTION

[0029] The subject matter of embodiments of the present invention is described here with specificity to meet statutory requirements, but this description is not necessarily intended to limit the scope of the claims. The claimed subject matter may be embodied in other ways, may include different elements or steps, and may be used in conjunction with other existing or future technologies. This description should not be interpreted as implying any particular order or arrangement among or between various steps or elements except when the order of individual steps or arrangement of elements is explicitly described.

[0030] In embodiments of the present invention, polyethers are provided as antistatic agents for use in the manufacture and/or use of glass fiber insulation. The polyether antistatic agents provide several unexpected benefits over previously known glass fiber antistatic agents. As further explained below, the polyethers are effective at much lower relative humidity levels, and they may have one or more of the properties of lower viscosity, a neutral pH, low toxicity, low volatility, low flammability and minimal odor.

[0031] Exemplary polyether antistatic agents according to embodiments of the invention include organic polyether liquids, such as but not limited to polyethylene glycol (PEG), polypropylene glycol (PPG), glycerol polyethers such as the Jeffox products available from Huntsman, and similar compounds. In some embodiments, the polyether antistatic agents have low volatility, i.e., they have relatively high boiling points and flash points as compared to previously known antistatic agents for use in glass fiber insulation.

[0032] In one embodiment, a polyether antistatic agent according to the present invention has a molecular weight of less than about 2000 (less than about 2000 MW). In other embodiments, the polyether antistatic agent has a molecular weight of less than about 1000 (less than about 1000 MW). Polyether antistatic agents having molecular weights in this range may have a relatively low viscosity as compared to previously known antistatic agents, such that they can be applied to the glass fibers during their manufacture or use without the use of a solvent. Generally, as molecular weight increases, so does viscosity. Thus, while polyethers having higher molecular weights can be used as an antistatic agent, it may be desirable to dilute or dissolve these polyethers in a solvent to make them easier to apply.

[0033] In some embodiments polyethers according to the present invention may have a viscosity of less than about 600 cSt at 75 F., or less than about 200 cSt at 75 F. Even if a polyether liquid having less than about 2000 MW or less than about 1000 MW and/or a viscosity of less than about 600 cSt or less than about 200 cSt is used, however, it may be desirable to utilize a solvent to further reduce the viscosity of the antistatic agent.

[0034] Exemplary solvents suitable for use with the polyether antistatic agents described herein include, but are not limited to, organic soluble electrolytes such as calcium acetate, lithium acetate, amine acetates (e.g., triethanolamine acetate (TEA)), sodium benzoate, and combinations thereof. Another possible solvent for use with the polyether antistatic agents described herein includes water, which may be used on its own or with one or more of the organic soluble electrolytes described herein or with other suitable solvents. As the polyether antistatic agents described herein have a lower viscosity than previously known antistatic agents, however, less solvent can be used than in previously known antistat formulations. It will be recognized that a person skilled in the art could select a suitable solvent or combination of solvents and adjust the amount(s) added to the polyether antistatic agent to achieve desired performance characteristics.

[0035] With reference to the data set forth below, polyether antistatic agents according to the present invention have surprisingly been found to neutralize the static charge in glass fiber insulation at a much lower relative humidity than previously known antistatic agents used in such insulation. In addition, it has surprisingly been found that by using the polyether antistatic agents according to the present invention, less antistatic agent and/or less (or no) solvent is required, reducing the amount of antistatic agent (or antistatic agent solution) that must be applied to the glass fibers (the use rate).

[0036] In addition, because these polyether antistatic agents are lower in viscosity, they are easier to apply to the glass fibers and they can be applied neat (without a solvent). The agents thus do not buildup excessively on glass fiber manufacturing equipment and unbonded insulation application equipment. This reduced buildup reduces the need for equipment maintenance as well as minimizes the amount of organic residue that might become fuel during a process fire. This reduces the potential for fires to start as well as reduces the severity and duration of any fires that do occur. Many of these agents may also have one or more of the properties of a neutral pH, low toxicity, low volatility, low flammability, and minimal odor, resulting in a reduction in skin irritation issues, metal corrosion, process fires, and odor complaints.

[0037] Further, because the polyether antistatic agents can be applied to the glass fibers without solvents such as water, or with substantially reduced amounts of solvent, no drying equipment is needed in the manufacturing process and minimal residual moisture is left on the product, which might otherwise degrade the quality of the glass fibers.

[0038] The lubricity of the polyether antistatic agents according to the present invention has also been found to reduce airborne dust levels during manufacture and product installation, which may enable a reduction in the use of other dedusting agents. For example, typical glass fiber constructions currently in use may include up to about 0.8% by weight of a dedusting agent such as mineral oil. It has been surprisingly discovered, however, that glass fiber formulations including the polyether antistatic agents described herein can be formed using substantially lower amounts of dedusting agents, for example less than 0.5% by weight dedusting agent or even less than 0.3% by weight dedusting agent.

[0039] In addition, the reduction in antistatic agent use rate, combined with the reduction in dedusting agent use rate, results in a lower installed density of loose-fill insulation, which improves the thermal performance (R-value) of the insulation per unit of mass.

[0040] The polyether antistatic agents according to the present invention may be applied to bonded glass fiber insulation during the manufacture of the batt or roll. In particular, they may be sprayed or otherwise applied to the re-feed fibers in the re-feed process. An exemplary method for forming bonded glass fiber insulation including the polyether antistatic agents according to the present invention is described below and illustrated in FIG. 1. In the method 100, glass fibers 105 are laid onto a batt or roll 110 according to known methods. The edges of the roll or batt are trimmed 120, and the batt or roll is finished 130 according to known methods. The trimmings, including glass fibers, are ground 140 in a mill, and the polyether antistatic agents according to the present invention are applied 150 to the trimmings, which can then be recycled 155 and re-used in the manufacturing process.

[0041] The polyether antistatic agents according to the present invention may also be applied to unbonded glass fibers during their manufacture or during the installation of the fibers. For example, they could be sprayed onto or otherwise applied to the unbonded fibers during the manufacture of the fibers. Glass fibers may be formed by a rotary fiberization process, a purely exemplary description of which is described in International application no. PCT/US2007/011116, published as WO/2007/133549 on Nov. 22, 2007, the disclosure of which is incorporated by reference in its entirety. An exemplary method for forming unbonded glass fiber insulation including the polyether antistatic agents according to the present invention is described below and illustrated in FIG. 2. In the method 200, glass filaments are formed by, for example, a rotary fiberization process 210. The filaments are cut 220 into glass fibers, and the polyether antistatic agent according to the present invention is applied to the cut fibers 230. Although not illustrated in the figures, it will be understood that the polyether antistatic agent may be applied to the glass filaments during the filament formation process 210, prior to cutting the glass fibers 220, or after formation of the glass filaments but prior to packaging them 220.

[0042] Alternatively, the polyether antistatic agents could be applied to the fibers during installation of the insulation, for example by spraying or otherwise applying them to the glass fibers as they are being sprayed onto the surface to be treated/insulated. An exemplary method for applying the polyether antistatic agents to unbonded glass fibers during installation of the insulation is described below and illustrated in FIG. 3. In the method 300, glass fibers are formed, packaged and transported to a work site 310 according to known methods (such as the rotary fiberization process described above). At the work site (such as a building where the insulation is to be installed), the fibers are transported 320 through a pipe and blown onto the surface to be treated 330. The polyether antistatic agents according to the present invention are applied to the fibers as the fibers are blown out of the pipe 325 or, alternatively, the polyether antistatic agent may be applied to the fibers while they are being transported through the pipe 315 or directly to the fibers as they pass through the blowing machine (not shown).

[0043] The polyether antistatic agents could also be applied to the glass fibers after being sprayed onto the surface to be treated/insulated, although it will be recognized that static charges could build up during the application process, resulting in undesirable effects such as those discussed herein.

[0044] The polyether antistatic agents according to the present invention are more effective in reducing static charge in the insulation than previously known agents, whether the polyether is mixed with a solvent (e.g., one of the organic soluble electrolytes described above and/or water) or applied to the glass fibers neat.

[0045] When the polyether is pre-mixed with electrolyte, the mixture becomes more electrically conductive, thus reducing any static charge that is generated by rubbing of the glass fibers. Accordingly, the more conductive the antistatic agent, the better performance in controlling static.

[0046] In formulations in which the polyether antistatic agent is applied to glass fibers without a solvent, i.e., neat, the polyether agent functions as a lubricant to reduce friction between fibers or fiber/substrates, thus reducing the static generated. In addition, small amounts of residual conductive materials, such as mineral components from process water on the surface of the glass fibers, results in some electrical conductivity when they dissolve in the polyether agent applied to the fibers. Further, as mentioned above, the hydroscopic attraction of water from the atmosphere may also provide electrical conductivity. These properties result in less static charge generated in the glass fibers and some residual conductivity on the glass fiber surface, the combined effects of which result in the polyether agent functioning as a suitable antistatic agent when applied neat to the glass fibers.

[0047] The invention is further illustrated by the following examples, which are not to be construed in any way as imposing limitations upon the scope thereof.

Example 1

[0048] Table 1 provides static ratings of insulation treated with previously known antistatic agents as compared to the polyether antistatic agents according to the present invention:

TABLE-US-00001 TABLE 1 Static Rating Static Rating 20% RH 10% RH Control (standard antistat) 0.5 2.5 Sample (PEG antistat) 0.5 1 Static rating scale: 0 - no sign of static charge; 1 - minimal static, normal product behavior; 2 - excessive static, buildup on walls and hose; 3 - extreme static, unable to blow material

[0049] The Control formulation was applied to glass fibers as a 79/21 mixture of solvents and a quaternary amine. The control (standard antistat) was Larostat 264, available from BASF. An equivalent weight percent of the Sample formulation was applied to glass fibers in neat form. The PEG was Pogol 200, available from Huntsman.

[0050] For both the Control and the Sample, the treated glass fibers were blown into a test boat in 20% relative humidity (RH) and 10% RH conditions and a semi-quantitative assessment of the static charge of the glass fibers was made.

[0051] From the data in Table 1, it is shown that at 20% RH the Sample (PEG antistatic agent) functioned similarly to the Control agent at the same application rate of active antistatic component. This is primarily due to the ability of both antistatic agents to absorb water vapor from the air, which reduces the static charge due to the polar nature of the water.

[0052] At 10% RH, however, it can be seen that the Sample provided a substantial improvement (reduction in static charge) over the Control agent. At such low humidity levels, the Control agent cannot absorb sufficient water vapor from the air to dissipate the static charge. In contrast, although the Sample is also limited in its ability to absorb water vapor from the air, the polyether antistatic agent acts as a lubricant to reduce friction and thus the static generated.

Example 2

[0053] Table 2 provides coverage performance for insulation treated with previously known antistatic agents as compared to the polyether antistatic agents according to the present invention:

TABLE-US-00002 TABLE 2 Coverage Performance Coverage (ft.sup.2) Bag 1 Bag 2 Control (standard antistat) 58.8 60.8 Control (standard antistat; humidity aged) 59.8 60.1 Sample (PEG antistat) 61.4 63.9 Sample (PEG antistat; humidity aged) 65.1 62.1

[0054] The Control formulation was applied to glass fibers as a 79/21 mixture of solvents and a quaternary amine. The control (standard antistat) was Larostat 264, available from BASF. An equivalent weight percent of the Sample formulation was applied to glass fibers in neat form. The PEG was Pogol 200, available from Huntsman.

[0055] Control and Sample bags were humidity aged in 90 degree Fahrenheit, 90% RH conditions for seven days. Each of the Controls and Samples were blown into a standard test boat and their R-30 coverage was calculated in square feet. As shown in Table 2, for each bag the Sample exhibited improved coverage as compared to its respective Control, and showed no evidence of reduced coverage due to the hot/humid aging conditions. This improvement in coverage is due to the elimination of solvent, especially water, from the antistat, which is known to degrade glass fibers during storage resulting in fiber breakage and increased installed density. This higher installed density reduces coverage for a given bag weight.

Example 3

[0056] Table 3 provides considers dust generated by insulation treated with previously known antistatic agents as compared to the polyether antistatic agents according to the present invention:

TABLE-US-00003 TABLE 3 Dust Generation Dust (in water) Control (standard antistat/standard oil) 1.6 Control (standard antistat/reduced oil) 2.7 Sample (PEG antistat/standard oil) 1.3 Sample (PEG antistat/reduced oil) 1.6 Dust rating scale: 0.0-1.0 Extremely low dust 1.0-2.0 Typical dust level 2.0-3.0 High dust but still within specification >3.0 Excessive dust; outside specification

[0057] The Control formulation was applied to glass fibers as a 79/21 mixture of solvents and a quaternary amine. The control (standard antistat) was Larostat 264, available from BASF. An equivalent weight percent of the Sample formulation was applied to glass fibers in neat form. The PEG was Pogol 200, available from Huntsman. The dedusting oil was a light mineral oil with the standard application rate equal to 0.8% by weight of the product. The reduced oil application rate was only 0.24% by weight of the product (i.e. a 70% reduction from the standard rate).

[0058] Dust is measured during the coverage blow check process. A device draws ambient air from the blowing area through a filter screen until a steady-state pressure drop is measured. The dust measurements reflect the pressure drop across the filter screen as measured in inches of water.

[0059] From the data in Table 3, it is shown that each Sample exhibited improved (lower) dust levels as compared to its respective Control. Further, while the dust results for the Control with reduced oil were almost out of specification, the Sample with reduced oil, while having more dust than the Sample with standard oil, was well within the specification. This confirms that use of the lubricious polyether antistatic agents of the present invention allows less dedusting agent to be used in the glass fiber formulation, while still providing satisfactory dust generation results.

[0060] As used herein and in the appended claims, the singular forms a, an, and the include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a process includes a plurality of such processes and reference to the device includes reference to one or more devices and equivalents thereof known to those skilled in the art, and so forth.

[0061] Also, the words comprise, comprising, include, including, and includes when used in this specification and in the following claims are intended to specify the presence of stated features, integers, components, or steps, but they do not preclude the presence or addition of one or more other features, integers, components, steps, acts, or groups.

[0062] Different arrangements of the components depicted in the drawings or described above, as well as components and steps not shown or described are possible. Similarly, some features and subcombinations are useful and may be employed without reference to other features and subcombinations. Embodiments of the invention have been described for illustrative and not restrictive purposes, and alternative embodiments will become apparent to readers of this patent. Accordingly, the present invention is not limited to the embodiments described above or depicted in the drawings, and various embodiments and modifications can be made without departing from the scope of the claims below.