WO2013107033A1

WO2013107033A1 - Solvent-borne polyurethane-coated garments and preparation methods thereof

Info

Publication number: WO2013107033A1
Application number: PCT/CN2012/070643
Authority: WO
Inventors: Linan Zhao; Yvonne Abel; Claudia Hansen
Original assignee: Honeywell International Inc
Current assignee: Honeywell International Inc
Priority date: 2012-01-20
Filing date: 2012-01-20
Publication date: 2013-07-25
Anticipated expiration: 2014-07-20

Description

SOLVENT-BORNE POLYURETHANE-COATED GARMENTS AND PREPARATION

METHODS THEREOF

TECHNICAL FIELD

[0001] The present invention relates generally to coated garments and methods for forming coated garments, and more particularly relates to solvent-borne polyurethane- coated garments, such as solvent-borne polyurethane-coated textile glove liners and the like, that are substantially free of DMF and methods for forming such coated garments.

BACKGROUND

[0002] Polyurethane-coated garments, such as polyurethane-coated textile glove liners and the like, are commonly worn as protective garments and/or to provide a light gripping surface for use in working environments. In one conventional manufacturing process, a textile glove liner is dipped into a solvent-borne polyurethane coating solution that contains polyurethane resin dissolved in dimethyl formamide (DMF) to selectively coat the glove liner with the solution. The selectively solution-coated glove liner then undergoes a series of immersions in water to facilitate leaching of the DMF and gelling of the polyurethane resin. Although much of the DMF is removed during the water immersion stage, the finished glove still contains some residual DMF. DMF is believed to be potentially detrimental to people's health, the ecosystem, and the environments surrounding the manufacturing plants.

[0003] In efforts to reduce the use of DMF in the production of polyurethane-coated garments, another conventional manufacturing process uses a water-borne polyurethane coating solution to selectively coat a glove liner. The water-borne polyurethane coating solution uses water instead of DMF to dissolve a polyurethane resin that is specifically formulated on the basis of water serving as a vehicle to dissolve and carry the

polyurethane. Unfortunately, the performance of water-borne polyurethane-coated glove liners is not as good as DMF solvent-borne polyurethane-coated glove liners. For example, the abrasion resistance is much lower for water-borne polyurethane-coated glove liners than for DMF solvent-borne polyurethane-coated glove liners. Additionally, the comfort and feel for a wearer or user is not as good with water-borne polyurethane-coated glove liners, e.g., reduced softness and warmth, as it is for DMF solvent-borne polyurethane- coated glove liners.

[0004] Accordingly, it is desirable to provide polyurethane-coated garments and methods for making polyurethane-coated garments that are substantially free of DMF without compromising the performance of the coated garments. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background.

BRIEF SUMMARY

[0005] Solvent-borne polyurethane-coated garments and methods for forming solvent- borne polyurethane-coated garments are provided herein. In accordance with an exemplary embodiment, a method for forming a solvent-borne polyurethane-coated garment comprises the steps of combining a polyurethane resin and an organic solvent to form a polyurethane resin-solvent solution. The organic solvent is substantially free of DMF and comprises 2-methoxy ethyl acetate, diethylene glycol monomethyl ether, butyrolatone, 2-methoxy- 1,3-dioxolane, dipropylene glycol methyl ether, propylene glycol n-propyl ether, dipropylene glycol dimethyl ether, tripropylene glycol methyl ether, propyl cello solve including ethylene glycol propyl ether, butyl triglycol including ethylene glycol n-butyl ether, dimethylacetamide, or combinations thereof. A garment is contacted with the polyurethane resin-solvent solution.

[0006] In accordance with another exemplary embodiment, a method for forming a solvent-borne polyurethane-coated garment is provided. The method comprises the steps of combining a polyurethane resin and an organic solvent to form a polyurethane resin- solvent solution. The organic solvent is substantially free of DMF and has a NFPA Health Rating of 1 or 0, a Hansen Solubility Parameter of from about 7.5 to about 13.5, and is miscible in water at a temperature of about 20°C or greater. A garment is contacted with the polyurethane resin-solvent solution.

[0007] In accordance with another exemplary embodiment, a solvent-borne

polyurethane-coated garment is provided. The solvent-borne polyurethane-coated garment comprises a garment and a solvent-borne polyurethane coating that is disposed on the garment. The solvent-borne polyurethane coating is substantially free of DMF. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and wherein:

[0009] FIG. 1 is a flowchart of a method for forming a solvent-borne polyurethane - coated garment in accordance with an exemplary embodiment;

[0010] FIG. 2 is a palm side elevation view of a solvent-borne polyurethane-coated glove liner in accordance with an exemplary embodiment; and

[0011] FIG. 3 is a dorsal side elevation view of the solvent-borne polyurethane-coated glove liner depicted in FIG. 1.

DETAILED DESCRIPTION

[0012] The following Detailed Description is merely exemplary in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description.

[0013] Various embodiments contemplated herein relate to solvent-borne polyurethane- coated garments and methods for forming solvent-borne polyurethane-coated garments. Unlike the prior art, the exemplary embodiments taught herein combine a polyurethane resin and an organic solvent that is substantially free of DMF and that is not considered to be toxic or harmful. The term "substantially free of DMF" as used herein means that

DMF, if present, is in an amount that does not exceed about 10 ppm, such as about 7 ppm or less, such as about 4 ppm or less, such as about 1 ppm or less, for example about 0 ppm. In an exemplary embodiment, the polyurethane resin is soluble in the organic solvent and is mixed with the organic solvent to form a polyurethane resin-solvent solution. Some examples of suitable organic solvents for mixing with the polyurethane resin to form the polyurethane resin-solvent solution include 2-methoxyethyl acetate, diethylene glycol monomethyl ether, butyrolatone, 2-methoxy-l,3-dioxolane, dipropylene glycol methyl ether, propylene glycol n-propyl ether, dipropylene glycol dimethyl ether, tripropylene glycol methyl ether, propyl cellosolve including ethylene glycol propyl ether, butyl triglycol including ethylene glycol n-butyl ether, and/or dimethylacetamide. [0014] A garment, such as a textile glove liner or other handwear, footwear, or other small garment or the like, is contacted with the polyurethane resin-solvent solution to coat at least a portion of the garment with the polyurethane resin-solvent solution. In an exemplary embodiment, the organic solvent is miscible with water and the solution-coated garment is immersed in water to remove or leach at least a portion of the organic solvent and to gel the polyurethane resin to form a solvent-borne polyurethane-coated garment. The term "solvent-borne polyurethane" as used herein refers to polyurethane that is formulated on the basis of hydrocarbon solvents serving as a vehicle to dissolve and carry the polyurethane. The inventors have found that by forming the solvent-borne

polyurethane-coated garment using an organic solvent that is substantially free of DMF, the solvent-borne polyurethane-coated garment is substantially free of DMF and the performance of the coated garment is not compromised relative to a DMF solvent-borne polyurethane-coated garment.

[0015] Referring to FIG. 1, a method 100 for forming a solvent-borne polyurethane - coated garment in accordance with an exemplary embodiment is provided. A

polyurethane resin and an organic solvent are combined (step 102) to form a polyurethane resin-solvent solution. The polyurethane resin can be an aliphatic or aromatic solvent- borne polyurethane resin that is a one component system (e.g. IK system) or a two component system (e.g. 2K system). One such suitable polyurethane resin is Hisin HW- 1630 one component polyurethane resin manufactured by Heung II Polychem Co., Ltd, which is headquartered in Busan, Korea.

[0016] In an exemplary embodiment, the organic solvent is substantially free of DMF and is not considered to be toxic or harmful. Additionally, the polyurethane resin is soluble in the organic solvent. In an exemplary embodiment, the organic solvent comprises 2-methoxyethyl acetate, diethylene glycol monomethyl ether, butyrolatone, 2- methoxy-l,3-dioxolane, dipropylene glycol methyl ether, propylene glycol n-propyl ether, dipropylene glycol dimethyl ether, tripropylene glycol methyl ether, propyl cellosolve including ethylene glycol propyl ether, butyl triglycol including ethylene glycol n-butyl ether, and/or dimethylacetamide; such as 2-methoxyethyl acetate, butyrolatone, 2- methoxy-l,3-dioxolane, dipropylene glycol methyl ether, propylene glycol n-propyl ether, dipropylene glycol dimethyl ether, and/or tripropylene glycol methyl ether; such as 2- methoxy-l,3-dioxolane, dipropylene glycol methyl ether, and/or propylene glycol n-propyl ether; for example dipropylene glycol methyl ether and/or propylene glycol n-propyl ether.

[0017] In an exemplary embodiment, the organic solvent has a National Fire Protection Association (NFPA) Health Rating of 1 or 0. The NFPA has developed a rating system for indicating the health, flammability, reactivity, and special hazards for many chemicals. A NFPA Health rating of 4 corresponds to a chemical that may be fatal on short exposure and for which specialized detection equipment is required. A NFPA Health rating of 3 corresponds to a chemical that is corrosive or toxic and of which skin contact or inhalation should be avoided. A NFPA Health rating of 2 corresponds to a chemical that may be harmful if inhaled or absorbed. A NFPA Health rating of 1 corresponds to a chemical that may be irritating. A NFPA Health rating of 0 corresponds to a chemical that has no unusual hazard.

[0018] In an exemplary embodiment, the organic solvent has a Hansen Solubility Parameter (HSP) of from about 7.5 to about 13.5, such as from about 8 to about 12, for example from about 9 to about 11, and the polyurethane resin has a HSP of about 10. The HSP is a three component measuring system that includes a dispersion force component, a hydrogen bonding component, and a polar component. HSPs are calculated at 25 °C with ChemSW's Molecular Modeling Pro v.6.1.9 software package, which uses an unpublished proprietary algorithm that is based on values published in the Handbook of Solubility Parameters and Other Parameters by Allan F. M. Barton (CRC Press, 1983) for solvents obtained experimentally by Charles Hansen. All values of the HSP reported herein (see also Table 1 below) are in units of (megaPascals) 1/2. The HSP was developed as a way of predicting if one material will dissolve in another material to form a solution. The HSP is based on the theory that "like materials" dissolve "like materials." In particular, if two materials have similar HSP values, then the two materials are miscible with each other to form a solution. That is, the organic solvent having a HSP value, e.g., from about 7.5 to about 13.5, that is similar to the HSP value for the polyurethane resin, e.g., about 10, means that the organic solvent is capability of dissolving the polyurethane resin to form the polyurethane resin-solvent solution. Referring to Table 1, the HSP values of the non- limiting examples of suitable hydrocarbons for the organic solvent from above and of

DMF as a baseline are provided. As indicated, the listed hydrocarbons have HSP values that are similar to the HSP value of about 10 for the polyurethane resin and therefore, are capable of dissolving the polyurethane resin to form the polyurethane resin-solvent solution.

[0019] In an exemplary embodiment, the organic solvent is miscible in water at a temperature of about 20°C or greater, such as from about 25 to about 95°C, for example from about 60 to about 90°C. Table 1 also provides the solubility or miscibility of the non-limiting examples of suitable hydrocarbons for the organic solvent from above with water. Additionally, Table 1 also provides the solubility or miscibility of DMF with water as a baseline. As indicated, with the exceptions of dipropylene glycol dimethyl ether and dimethylacetamide, the listed hydrocarbons are completely miscible with water.

Dipropylene glycol dimethyl ether was found to be partially miscible in water up to a ratio of about 53 mL of hydrocarbon to about 100 mL of water at about 25°C.

Dimethylacetamide was found to be miscible only in cold water, e.g., at a temperature below about 20°C.

[0020] In an exemplary embodiment, the organic solvent has a flash point of about 30°C or higher and a boiling point of about 200°C or less. As illustrated in Table 1, with the exception of tripropylene glycol methyl ether, the listed hydrocarbons have flash points of greater than about 30°C and boiling points of about 200°C or less.

[0021] TABLE 1

[0022] Referring back to FIG. 1, in an exemplary embodiment, the polyurethane resin and the organic solvent are combined at a weight ratio of the polyurethane resin to the organic solvent of from about 1:1.4 to about 1:1.8 and are mixed together, such as in a first dipping tank, to form the polyurethane resin-solvent solution. In one example, the polyurethane resin and the organic solvent are mixed at a mixing temperature of from about 15 to about 30°C for a mixing time of from about 4 to about 24 hours. In an exemplary embodiment, the polyurethane resin-solvent solution has a viscosity of from about 800 to about 1000 centipoises (cps).

[0023] Various additives may also be incorporated into the polyurethane resin-solvent solution. Some non-limiting examples of suitable additives include pigment(s)/colorant(s), deforming reagent(s), and titanium dioxide. In an exemplary embodiment, the

polyurethane resin-solvent solution also comprises pigment(s) in an amount of from about 0.4 to about 1 weight percent (wt. %) and/or deforming reagent(s) in an amount of from about 0.1 to about 0.3 wt. %. Other suitable additives known to those skilled in the art may also be incorporated into the polyurethane resin-solvent solution.

[0024] In an exemplary embodiment, the polyurethane resin-solvent solution is heated (step 104) to a solution temperature of from about 40 to about 50°C. A garment, which may be preheated (step 106) to a garment temperature of from about 50 to about 60°C, is contacted with the polyurethane resin- solution (step 108) to coat the garment and form a PU resin-solvent coated garment. In one example, the garment is dipped into the first dipping tank that contains the polyurethane resin- solution to selectively coat the garment. In an exemplary embodiment, the garment comprises polyamide fibers, polyester fibers, cotton, rayon fibers, ultra-high molecular weight polyethylene fibers, aramid fibers, elastane fibers, acrylic fibers, yarn, blended yarns, and/or synthetic leather.

[0025] Next, at least a portion of the organic solvent is removed from the PU resin- solvent coated garment (step 110) to form a solvent-borne polyurethane-coated garment. In an exemplary embodiment, at least a portion of the organic solvent is removed from the PU resin-solvent coated garment by contacting the PU resin-solvent coated garment with a solvent-water solution that comprises water and the organic solvent as discussed above where the organic solvent is present in an amount of from about 5 to about 20 wt. , such as from about 15 to about 20 wt. , of the solvent- water solution, which also promotes gelling or solidification of the polyurethane resin. In one example, the PU resin-solvent coated garment is removed from the first dipping tank and is immersed sequentially in a series of dipping tanks including a second dipping tank that contains the solvent-water solution and a third dipping tank that contains primarily water. In an exemplary

embodiment, the solvent- water solution comprises water and the organic solvent as discussed above where the organic solvent is present in an amount of from about 5 to about 15 wt. % of the solvent- water solution. In an exemplary embodiment, the water and solvent-water solution contained in the series of dipping tanks are at a temperature(s) of from about 60 to about 90°C to promote leaching of the organic solvent from the PU resin- solvent coated garment.

[0026] After using water to remove at least a portion of the organic solvent, the solvent- borne polyurethane-coated garment may also be introduced to an oven (step 112) to promote drying and/or to help remove any residual organic solvent from the coated garment. In an exemplary embodiment, the oven is operating at a temperature of from about 100 to about 130°C.

[0027] Referring to FIGS. 2 and 3, a palm side elevation view and a dorsal side elevation view, respectively, of a solvent-borne polyurethane-coated glove liner 10 in accordance with an exemplary embodiment is provided. As illustrated, the solvent-borne polyurethane-coated glove liner 10 comprises a glove liner 12 that is selectively coated, e.g., on an outer surface of the glove liner 12, with a solvent-borne polyurethane coating

14. Non-limiting examples of materials used to form the glove liner 12 include polyamide fibers, polyester fibers, cotton, rayon fibers, ultra-high molecular weight polyethylene fibers, aramid fibers, elastane fibers, acrylic fibers, yarn, blended yarns, and/or synthetic leather. Other suitable materials known to those skilled in the art of polyurethane-coated garments may also be used to form the glove liner 12. In an exemplary embodiment, the solvent-borne polyurethane coating 14 is formed of a polyurethane resin, e.g., solvent- borne polyurethane resin, that was dissolved in an organic solvent as discussed above without using DMF and therefore, is substantially free of DMF.

[0028] Accordingly, solvent-borne polyurethane-coated garments and methods for forming solvent-borne polyurethane-coated garments have been described. Unlike the prior art, the exemplary embodiments taught herein combine a polyurethane resin and an organic solvent that is substantially free of DMF and that is not considered to be toxic or harmful. The polyurethane resin is soluble in the organic solvent and is mixed with the organic solvent to form a polyurethane resin-solvent solution. A garment is contacted with the polyurethane resin-solvent solution to coat at least a portion of the garment with the polyurethane resin-solvent solution. In an exemplary embodiment, the organic solvent is miscible with water and the solution-coated garment is immersed in water to remove or leach at least a portion of the organic solvent and to gel the polyurethane resin to form a solvent-borne polyurethane-coated garment. By forming the solvent-borne polyurethane- coated garment using an organic solvent that is substantially free of DMF, the solvent- borne polyurethane-coated garment is substantially free of DMF and the performance of the coated garment is not compromised relative to a DMF solvent-borne polyurethane- coated garment.

[0029] While at least one exemplary embodiment has been presented in the foregoing detailed description of the invention, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment of the invention. It being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the invention as set forth in the appended claims.

Claims

CLAIMS What is claimed is:

1. A method for forming a solvent-borne polyurethane-coated garment, the method comprising the steps of:

combining a polyurethane resin and an organic solvent to form a polyurethane resin-solvent solution, wherein the organic solvent is substantially free of DMF and comprises 2-methoxyethyl acetate, diethylene glycol monomethyl ether, butyrolatone, 2-methoxy-l,3-dioxolane, dipropylene glycol methyl ether, propylene glycol n-propyl ether, dipropylene glycol dimethyl ether, tripropylene glycol methyl ether, propyl cellosolve including ethylene glycol propyl ether, butyl triglycol including ethylene glycol n-butyl ether, dimethylacetamide, or

combinations thereof; and

contacting a garment with the polyurethane resin-solvent solution.

2. The method of claim 1, wherein the step of combining comprises combining the polyurethane resin and the organic solvent at a weight ratio of the polyurethane resin to the organic solvent of from about 1:1.4 to about 1:1.8.

3. The method of claim 1, wherein the step of combining comprises mixing the polyurethane resin and the organic solvent together to form the polyurethane resin-solvent solution having a viscosity of from about 800 to about 1,000 cps.

4. The method of claim 1, wherein the step of contacting comprises contacting the garment with the polyurethane resin-solvent solution to form a PU resin- solvent coated garment, and wherein the method further comprises the step of: removing at least a portion of the organic solvent from the PU resin-solvent coated garment with water to form a PU coated garment comprising a solvent- borne polyurethane coating that is substantially free of DMF.

5. The method of claim 4, wherein the step of removing comprises contacting the PU resin-solvent coated garment with water at conditions effective to leach the organic solvent from the PU resin-solvent coated garment.

6. The method of claim 5, wherein the step of removing comprises contacting the PU resin-solvent coated garment with a solvent-water solution prior to the step of contacting the PU resin-solvent coated garment with water.

7. The method of claim 6, wherein the step of contacting comprises contacting the PU resin-solvent coated garment with the solvent-water solution that comprises water and the organic solvent that is present in an amount of about 5 to about 15 wt. % of the solvent-water solution.

8. A method for forming a solvent-borne polyurethane-coated garment, the method comprising the steps of:

combining a polyurethane resin and an organic solvent to form a

polyurethane resin-solvent solution, wherein the organic solvent is substantially free of DMF and has a NFPA Health Rating of 1 or 0, a Hansen Solubility

Parameter of from about 7.5 to about 13.5, and is miscible in water at a

temperature of about 20°C or greater; and

contacting a garment with the polyurethane resin-solvent solution.

9. The method of claim 8, wherein the step of combining comprises combining the polyurethane resin and the organic solvent that has a flash point of about 30°C or higher, and a boiling point of about 200°C or less.

10. A solvent-borne polyurethane-coated garment comprising:

a garment; and

a solvent-borne polyurethane coating that is disposed on the garment and that is substantially free of DMF.