CA1279754C - Temperature adaptable textile fibers and methods of preparing same - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

Temperature adaptable textile fibers are provided in which phase-change or plastic crystalline materials are filled within hollow fibers or impregnated upon non-hollow fibers. The fibers are produced by applying solutions or melts of the phase-change or plastic crystalline materials to the fibers. Cross-linked polyethylene glycol is especially effective as the phase change material, and, in addition to providing temperature adaptability, it imparts improved properties as to soil release, durable press, resistance to static charge, abrasion resistance, pilling resistance and water absorbency.

Description

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1 TEMPERATU~E ADaPTABLE TE~TILE FIBERS AND MET~OD

3 BACKGROUND OF T~E INVENTION

4 Field of the Invention ~his invention relates to modified textile 6 fibers.
7 Description of the Prior Art 8 The concept o~ preparing a temperature-adaptable 9 hollow fiber has been previously demonstrated and described in U.S. Patent 3,607,591. This invention ll incorporates a gas into liquid inside the fiber that 12 increases the diameter o~ the fiber and thus increases 13 its thermal insulation value when the liquid solidifies 14 and the solubility of the gas decreases. However, this invention exhibits serious limitations. It is limited 16 to use with only hollow textile fibers and is only 17 applicable in cold weather situations, i.e~, when -the 18 environmental temperature drops below the freezing 19 point of the liquid in the fiber. Furthermore, this modified hollow fiber system was not evaluated ~or its 21 ability to reproduce lts thermal effect after various 22 heating and cooling cycles.
23 The aerospace industry has reported some 24 phase-change materials (inorganic salt hydrates such as calcium chloride hexahydrate, lithium nitrate 26 trihydrate, zinc nitrate hexahydrate and polyethylene 27 glycol with an average molecular wei~ht of 60 ~ for :

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1 uses in spacecraft (Hale, et al., "Phase Change Materials 2 Handbook", NASA Contractor Report CR-61363, Sept. 1971).
3 These ma-terials have also been used in solar collectors 4 and heat pumps in residences (Carlsson, et al., Document D12:1978, Swedish Council for Building Research).

6 However, in these and similar publications, the 7 suitability of phase-change materials for effective and 8 prolonged heat storage and release is inflllenced by the 9 substrate in which they are stored, its geometry and thickness, the effect of impurities and the tendency of 11 the phase-change materials to supercool and exhibit 12 reversible melting and crystallization. Moreover, and 13 perhap~s the most significant deficiency and limitation of 14 the above recommendations,~ is the fact tha-t the phase-change materials were recommended as incorporated 16 into metal containers, plastic pipes and other nonporous 17 substrates or very thick insulation such as wall board.
18 No process or suitable conditions for the incorporation of 19 these types of materials into hollow or non hollow textile fibers has been described. Therefore, the problem of 21 choosing a textile fiber and combining it with a 22 phase-change material in order to produce thermal storage 23 and release properties that could be retained for a 24 minimum of 5 heating and cooling cycles is an extremely difficult one.
26 In addition to substances that store or release 27 thermal energy due to melting and/or crystallization 28 (phase-change materials) there is another class of 29 substances that are characterized by their high enthalpies or thermal storage and release properties. These 31 substances are commonly called plastic crystals, and have 32 extremely high -thermal storage or release values that 33 occur prior to and without melting, i.e., they have 34 thermal energy available without undergoing a change of stage such~as solid to liquid (melting) or liquid to solid S L~

1 (crystallization). Although the precise reasons why 2 plastic crystals exhibit such unique thermal behavior 3 prior to a change of state have not been verified, this 4 thermal effect is believed to be due to a conformational and/or rotational disorder in these substances. Plastic 6 crystal ma-terials such as pentaerythritol and other 7 polyhydric alcohols have been recommended fcr use in 8 passive architectural solar designs and active solar 9 dehumidifier or solar cooling systems (D. K. ~enson, et al., Proc. Eleventh No. Am. Thermal Analysis Conf. 1981) 11 because of their high thermal storage and release values 12 that occur much below their melting point. However, as 13 with the phase-change materials, no process or suitable 14 condi-tions for the incorporation of these plastic crystals into hollow or non-hollow textile fibers has been 16 described.

18 Temperature-adaptable textile fibers are provided 19 which store heat when the temperature rises and release heat when the temperature decreases, in which phase-change 21 br plastic crystalline materials are filled within hollow 22 fibers, or impregnated upon non-hollow fibers.
23 The fibers are produced by dissolving the 24 phase-change or plastic crystalline materials in a solvent such as water, thereafter fillirlg the hollow fibers, or 26 impregnating the non-hollow fibers, with the solution 27 followed by removal of the solvent. Alternatively, in the 28 case of phase-change materials, the material may be 29 applied to the fibers from a melt rather than solution.
The resultant product is a modified fiber which is 31 temperature adaptable in both hot and cold environments 32 for as many as 150 heating and cooling cycles, by 33 releasing heat when the temperature drops, and storing 34 heat when the temperature rises. As such, fabrics made , ' : ' ' ~ ' ' ' ' .

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1 from such fibers may be used to protect plants and 2 animals, may be incorporated in protective clothing, and 3 generally speaking may be employed in environments where 4 temperature fluctuations need to be minimized.
When polyethylene glycol is used as the impregnating 6 material, it is insolubilized on the fiber by 7 cross-linking, and the resultant product imparts valuable 8 properties to the fabric, in addition to thermal 9 properties, including the properties of soil release, durable press, resistance to static charge, abrasion 11 resistance, pilling resistance and water absorbency.
12 Furthermore, polyethylene glycol may be impregnated on 13 cellulosic fibers other' than textile fabrics, such as 14 papar and wood pulp fibers, for the purpose of imparting the above properties thereto.

16 DESCRIPTION OF T~E PREFERRED EMBODIMENTS
17 In the practice of the present invention the 18 pnase-change or plastic crystalline materials which are to 19 be filled into such hollow fibers as rayon or polypropylene, or impregnated into non-hollow fibers such 21 as cotton or rayon, first are dissolved in a solvent to 22 form a solution. Water is a suitable solvent in most 23 instances, althou~h some materials are more readily 24 dissolved in alcohol such as ethyl alcohol or chlorinated hydrocarbons such as carbon tetrachloride.
26 Wide ranges of solution concentrations are 27 suitable. The solution should not be too viscous that it 28 interferes with the ability of the solution to fill the 29 hollow fibers or to evenly impregnate the non-hollow fibers, and it should not be too dilute that only minimal 31 amounts of material are deposited wi-thin or on the fibers.
32 Previously known techniques for filling hollow 33 fibers are suitable, such as taught in "Hollow Fibers 34 Manufacture and Application", editor Jeanette Scott, 1 published by Noyes Data Corp., 1981, and includes metering 2 the desired aqueous solution into the hollow fibers as 3 they are formed by extrusion during wet spinning.
4 As to impregnating non-hollow fibers, previously known immersion and coating techniques for textile fibers 6 are suitable, such as techniques for finishing or dyeing, 7 or imparting fire-retardancy or wash-and-wear.
8 As a laboratory procedure for filling small numbers 9 of fibers, the following method may be employed: A
plurality of fibers are formed into a bundle. One end of 11 the bundle is immersed in solution, while the other end is 12 snugly inserted into an open end of a plastic or rubber 13 tube or hose which is connected to an aspirator, thereby 14 drawing solution into the fibers.
After the solution has filled the hollow fibers, or 16 has coated the non-hollow fibers, solvent is removed from 17 the solution to deposi-t the material within or upon the 18 fibers. Prior art solvent removal techniques in the 19 textile art are suitable, such as air drying or oven drying. These techniques are well known in connection 21 with fabric finishing or dyeing, or imparting 22 flame-retardancy or wash-and-wear to -textiles. In some 23 instances, -the solven~ can be removed by reduced pressure 24 or solvent extraction.
In the case of non-hollow fibers, a preliminary 26 solvent removal step may be included such as the use of 27 squeeze rollers to remove excess solvent prior to drying.
28 Such a preliminary step is well known in the textile 29 treatment art.
During the primary drying step, the t~mperature 31 preferably i5 maintained below the melting point of the 32 phase-change material or below the solid-to-solid 33 transition temperature of the plastic crystalline 34 material.

~7~ ;4 1 After removal of solvent, in the casa of hollow 2 fibers, the fiber ends may be sealed as taught in the 3 previously mentioned book on hollow fibers, and thereafter 4 the fibers may be formed into woven or nonwoven fabric.
With regard to impregnating non~hollow fibers, the step of 6 treating the fibers with solution of the phase-change or 7 plastic crystalline material preferably is carried out 8 after the fibers have already been formed into fabric.
9 As an alternative to dissolving the phase-change material in a solvent prior to application to the fibers, 11 such materials may first be melted. Thereafter, the melt 12 itself is filled into or impregnated upon the fibers and 13 subseqùently cooled for the purpose of resolidification.
14 Any phase-change or plastic crystalline material which is chemically or physically compatible with the 16 fibers is suitable, which can be determined through 17 routine experimentation. The expression "chemically and 18 physically compatible", as used in the specification and 19 claims, means that the material does not react with the fibers so as to lose its phase-change or transition 21 properties, is capable of being filled within the hollow 22 fiber, or impregnated upon the non-hollow fiber, and, 23 specifically with regard to phase-change materials, the 24 material must be able, in its liquid phase, to be retained within the hollow fiber, or remain impregnated upon the 26 non-hollow fiber. The expression "phase-change ma-terial", 27 as used herein, refers to materials which trans~orm from 28 solid to liquid and back, at a particular temperature; and 29 "plastic crystalline material" refers to material which changes from one solid composition to another, and back, 31 at a particular temperature. It will be obvious that only 32 those materials whose temperature of phase change or 33 transition falls within a temperature of practical use for 34 the resultant fabric ordinarily should be employed in the practice of the present invention, although, under special - .

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~ t7 1 circumstances, it may be useful to employ a material whose 2 phase change or transition temperature falls outside this 3 normal range.
4 Preferably the phase-change materials are selected from the group consisting of congruent inorganic salt 6 hydrates and polyethylene glycols, while the plastic 7 crystalline ~aterials are polyhydric alcohols. More 8 particularly, the phase-change materials are selected from 9 the group consisting of calcium chloride hexahydrate in admixture with strontium chloride hexahydrate, lithiun 11 nitrate trihydrate and zinc nitrate hexahydrate, 12 polyethylene glycols having 5 to 5~ monomer units with an 13 average molecular weight ranging from 300 to 3350.
14 The polyhydric alcohols preferably are selecte~ from the group consisting of pentaerythritol, 2,2-dime-thyl-1, 16 3-propanediol, 2-hydroxymethyl-2-methyl-1,3-propanediol, 17 or amino alcohols such as 2-amino-2-methyl-l, 18 3-propanediol.
19 With regard to specific phase-change and plastic crystalline materials, preferred concentrations (weight 21 percent of solution) in aqueous solutions for application 22 to fibers are as follows (in some cases the amount of 23 material which is deposited in or on specific types of 24 fibers, after solvent removal, also is given):
(a) 10--40~ sodium sulfate decahydrate in 26 combination with 3-10~ sodium borate decahydrate added to 27 prevent supercooling.
28 (b) 45-80~ calcium chloride hexahydrate in 29 combination with 1-2.5~ strontium chloride hexahydrate added to prevent supercooling, 0.5-10.0 grams of material 31 deposited per gram of rayon or cotton fiber, and 0.4-1.6 32 grams per gram of polypropylene fiber.
33 (c) 80-95~ zinc nitrate hexahydrate, 0.5-17.0 grams 34 deposited per gram of rayon or cotton, and 1.0 to 1.6 gxams per gram of polypropylene.

1 (d) 80-100% lithium nitrate trihydrate, 3-10 grams 2 deposited per gram of rayon or cotton, and 0.2-1.4 grams 3 per gram of polypropylene.
(e) 15-65~ polyethylene glycol (300-3350 m.w.), 0.25-12.0 grams deposited per gram of rayon, cotton, wool, 6 polyester, polypropylene and so forth.
7 (f) 20-40% pentaerythritol, 1.0-2.0 grams deposited 8 per gram of rayon or cottom, and 0.4-0.8 grams per gram of 9 polypropylene.
(g) ~0-60% 2-amino-2-me-thyl-1,3-propanediol, 11 0.4-2.8 grams deposited per gram of rayon or cotton, and 12 0.8-1.2 grams per gram of polypropylene.
13 rh) 40-60% 2,2-dimethyl 1-1,3-propanediol, 0.4-2.8 14 grams deposited per gram of rayon or cotton, and 0;7-1.1 grams per gram of polypropylene.
16 (i) 40-60% 2-hydroxymethyl-2-methyl-1,3-pro-17 panediol, 0~5-5.0 grams per gram of rayon or cotton, and 18 0.6-1.0 grams per gram of polypropylene.
19 In the case of using polyethylene glycol as the phase change material, especially on non-hollow fibers, 21 the material preferably is cross-linked on the fiber to 22 make it water insoluble, and thereby resistant to 23 laundering. While there are several cross-linking agents 24 known in the prior art for polyethylene glycol, those having threa or more reactive sites, e.g., 1,3-bis 26 (hydroxymethyl)-4,5-dihydroxyimidazolidinone-2, more 27 commonly known as dihydroxydimethylol ethylene urea 28 (DMDHEU), have been able to achieve the appropriate degree 29 of cross-linking at the necessary amount of add-on. For instance, far more polyethylene glycol is placed on the 31 fiber in the practice of the present invention than was 32 previously done in the prior art of using polyethylene 33 glycol to impart durable press to fabrics; and, to date, 34 only the type of cross-linking agent as described abo~e has been able to achieve appropriate cross-linking at such - . .

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t~54 g 1 a degree of add-on. Thus, only trifunctional or greater 2 functionality cross-linking agents are suitable. In 3 addition, such cross-linking is carried out by removal of 4 solvant and occurs by an ionic mechanism rather than by free radical reactions promoted or caused by exposure of 6 the polyol to high energy radiation.
7 In the case of impregnating a non-hollow fiber, 8 such as cellulose, polyester, wool or other fiber, with 9 cross-linked polyethylene glycol, the preferred weight percent of the solution is about 30-60~ polyethylene 11 glycol (300-20,000 mw), and the add-on generally is from 12 0.15 to 1 grams per gram of fiber, preferably about 13 0.25-0`.50 grams/gram. Below 0.25 grams/gram, add-on 14 usually is not sufficient to impart thermal storage and release properties to the modified fibers, although other 16 above-enumerated properties still can be achieved.
17 Whatever the add-on, the degree of cross-linking is 18 important. Undercross-linking will not make the polymer 19 water insoluble. Overcross-linking destroys or negates thermal activity, and also can adversely affect other 21 properties such as tensile and abrasion properties, 22 particularly of cellulosic fibers and/or cellulosic-23 synthetic blends~
24 As to non-hollow cellulosic substrates, the polyethylene glycol may be cross-linked in the above 26 amounts to non-textile materials such as paper and wood 27 pulp fibers for the purpose of enhancing the properties 28 thereof.
29 When cross-linking the polyethylene glycol, it is important to impart a sufficient degree of cross-linking 31 so that the material is water insoluble. It is also 32 important to avoid too much cross-linking, which will 33 inhibit the material's ability to change phases. It has 34 been determined that the solution of the polyethylene glycol preferably should contain, by weight, about 8-16~

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1 DMD~EU as the cross-linking agent, and 0.5-5.0~ acid 2 catalyst, preferably mild catalysts such as magnesium 3 chloride/citric acid catalyst, sodium bisulfate, 4 p-toluenesulfonic acid or combinations of p-toluenesulfonic acid with other acid catalysts, in 6 order to make the polyethylene glycol water insoluble, 7 and yet able to retain its ability to change phases upon 8 heating and cooling. With high molecular weigh-t 9 polyethylene glycols, e.g., greater than 1500, specific acid catalysts such as p-toluenesulfonic acid by itself 11 or in admixture with other acid catalysts such as MgC12 12 and citric acid, are necessary to insolubilize the polyol 13 onto the fiber and impart the desired properties.
14 Typical small scale operating conditions ~or pad dry-cure and for applying cross-linked polyethylene 16 glycol to fibers include: a wet pick up of about 17 80-200%, drying at about 50-80C for about 3-9 minutes, 18 and curing at about 100-170C for about 0.5-5 minutes.
19 The ability to cure at lower temperatures, e.g.~ about 100-130C, and yet still be able to fix the polymer so 21 that it doesn't wash off is advantageous.
22 It should be understood that the polyethylene 23 glycol is impregnated on the fibers and is not part of a 24 copolymer fiber structure. Nor is it present as an additive for other materials impregnated on such fiber.
26 Still further, preferably it is unsubstituted, i.e., it 27 only has hydroxyl end groups.
28 Laundering studies show that the polyethylene 29 glycol-impregnated non-hollow fibers are durable for 50 launderings, that the beneficia; thermal properties are 31 retained, and that pilling resistance is much better than 32 that of an untreated surface laundered the same nunber of 33 times.
34 The capabilities of phase-change materials in the practice of the present invention varies from one 36 material to another. For example, many congruent ~'.,'",.' - '. . :

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1 inorganic salt hydrates exhibit a loss in thermal 2 effectiveness and a tendency to supercool after 50 3 heating and cooling cycles, whereas polyethylene glycol 4 does not do so up to 150 cycles. As another example, sodium sulfate decahydrate in combination with sodium 6 borate decahydrate loses its effectiveness after 5 7 heating and cooling cycles. Likewise, there is a 8 variation among the plastic crystalline materials. For 9 example, pentaerythritol is only moderately effective because it has a tendency to sublime from the fibers on 11 prolonged thermal cycling.
12 As a general rule, the plastic crystalline 13 materials are more advantageous than the phase-change 14 materials since the thermal storage and release effects of the former are not dependent on melting and 16 crystallization, and often occur at temperatures much 17 below such melting or crystallization temperatures.
18 Modified fibers containing suitable plastic crystal l9 materials have little tendency to supercool or lose thermal effectiveness on prolonged thermal cycling.
21 The hollow fibers preferably are rayon and 22 polypropylene of the single cavity type, but any hollow 23 fiber type such as polyester or polyamide, and hollow 24 fiber geometry such as multiple cavity are suitable. The non-hollow fibers preferably are cotton, mercerized 26 cotton, rayon fibers, yarns and/or fabrics, but other 27 non-hollow fibers are suitable such as wool and 28 polyamides. With specific regard to polyethylene gl~col 29 as the impregnating material for non-hollow fibers, the substrate may be wood pulp, paper, a diverse group of 31 natural and/or synthetic fiber types, e.g., cellulosics, 32 proteinaceous, polyester, polypropylene, polyamide, 33 glass, acrylic, blends of the preceding, and so forth.
34 Fibers with high moisture regain, i.e., 4~ or greater, such as rayon or cot-ton are preferred to fibers 36 such as polypropylene for incorporation of congruent 37 inorganic salt hydrates because rayon and cotton prolongs 38 the number of thermal cycles for which the modified 7S~

1 fibers are thermally effective. That is, these 2 phase-change materials lose some water of hydration or 3 lose waters of hydration at a rate much faster than 4 rehydration after prolonged thermal cycling. Rayon and cotton are superior to polypropylene in such situations 6 because (a) rayon and cotton have a greater affinity and 7 capacity for congruent inorganic salt hydrates and 8 provide initially higher thermal storage and release 9 values; and (b) they retain these desirable thermal characteristics for a longer number of cycles because of 11 their ability to provide water from the fiber and thus 12 minimize or retard dehydration of the hydrates.
13 Hydrophilic fibers are superior to hydrophobic 14 fibers in many instances because the former have much greater affinity for polyethylene glycol than the 16 latter. Presumably this is due to their hydrophilic 17 nature and ability to form hydrogen bonds with these 18 phase-change materials; and -thus, fibers such as rayon or 19 cotton retain greater amounts of the polyethylene glycol.
The minimum length of the hollow fibers that are to 21 be filled generally should be about 10 mm, because 22 smaller fibers are difficult to handle. The preferred 23 length is at least 30 mm. There is no maximum length, 24 and thus continuous filaments can be filled with the materials herein. Any non-hollow fiber length and 26 geometry may be modified by the present invention. The 27 process is suitable for trea-tment of woven and non-woven 28 yarns and fabrics or any other textile structure derived 29 from non-hollow fibers.
The thermal transfer properties of the product of 31 the present invention are illustrated in the following 32 examples.

34 Incorporation of Polyethylene Glycol (av. molecular wt. of 600) into 36 Hollow Rayon Fibers 37 Hollow rayon fibers (38 mm in length) were tied 9~S4 1 into a parallel fiber bundle, tightly aligned inside an 2 0-ring in a ver-tical posi-tion, and a 57% aq. solution of 3 polyethylelle glycol wi-th an average molecular weight of 4 600 (Carbowax 600) aspirated -t}-rough the fibers under reduced pressure for 30 minutes or until the solu-tion was G visually observed to be a-t the top of thc fiber. The 7 modified fibers were then cooled at -15C for 1 hour and 8 ~ried at 18C for 2~ hours -to remove excess water and 9 cause tl-e pllase-cll~rlge material to soll dif~. Excess solld on the ex-terior of the fiber was removed, then the 11 fiber was condi-tloned at 25C/~5~ ~l in a dessicator 12 containing KN02 to produce a modified fiber containing on 13 a weight/weigll-t basis, 7.0 grams of Carbowax 600*per gram 14 of rayon fiber. The modified fibers were thell evaluated for up to 150 heating and cooll!lg cycles a-t -40 to ~60C
lG for thelr ablli-ty to store and release thermal energy by 17 differential scanning calorimetry. ~t 1 heatirlg and 18 cooling cycle, the thermal energy available for storage 19 on increasing temperature was 39.1 calories/ gram ln the temperature interval of -3 to ~37C and -the thermal 21 energy available for release on decreasing -tempera-ture 22 42.6 calories/gram in the temperature interval of -23 to Z3 17C.
24 After 150 thermal cycles, the thermal energy Z5 available for storage was 41.9 calories/gram and for 26 releast 41.0 calories/gram for the same -temperature 27 intervals.
28 In contrast, unmodified hollow ra~on ibers af-ter 1 29 hea-ting and cooling cycle exhibited falrl~ linear behavior and had in tlle same temperature ranges, thermal 31 storage values o 16.2 calories/gram and release values 32 of 14.9 calories/gram due only to the specific hea-t of 33 the unmodified fiber.
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2 Incorporation of Polyethylene Glycol 3 (av. molecular wt. of 600) in-to Hollow 4 Polypropylene Fibers Hollow polypropylene fibers (135 mm ln length) were 6 prepared and treated as in Example 1 with a 57~ aqueous 7 solution of polyethylene glycol (Carbowax 600~, cooled, 8 dried and conditioned, as in Example 1, to produce a 9 modified fiber containing 1.2 grams of Carbowax 600* per gram of polypropylene iber. When the modified hollow 11 fibers were evaluated by thermal analysis for up to 50 12 heating~and cooling cycles at -40 to ~60C, their thermal 13 energy available for storage after 1 heating and cooling i4 cycle was 32.3 calories/gram in the temperature interval of -3 to +37C (increasing temperature) and for release 16 31.5 calories/gram in the temperatu~e interval of -23 to 17 ~17C ~decreasing temperature). After 50 thermal cycles, 18 thermal energy for storage in the modified fibers was 19 35.2 calories/gram and for release 26.9 calories/gram at the same temperature intervals for heating and cooling.
21 In contrast~ unmodified hollow polypropylene fibers 22 after 1 heating and cooling cycle exhibited fairly linear 23 behavior and had in the same temperature intervals, 24 thermal storage values of 16.9 calories/gram and release values of 15.4 calories/gram, due to only -the speclfic 26 heat of the unmodified fibers.

28 Incorporation of Polyethylene Glycol 29 (av. molecular w-t. of 3350) into Hollow Polypropylene Fibers 31 Hollow polypropylene fibers were treated as in 32 Example 2 with a 57.2~ aqueous solution of polyethylene ~ TR~

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glycol ( Carbowax 3350 ), cooled, dried, and condi tioned, 2 as in Example l, -to produce a modlfied fiber contalning 3 1. 0 gram of Carbowax 335(~ per gram of polypropylene 4 fil7er. When the modiEied hollow fibers were evaluated by tl~ermal analysis for up to 50 hea ting and cooling cycles 6 at -40 to ~80C, their thermal energy available or 7 storage af ter 1 heating and cooling cycle ~as 35. 6 a calor.ies/gram in the temperature interval 42 to 77C
9 ~increasil-ly -temperature) and for release 33.5 calories/gram in the tempera ture in-terval of 17 -to 52C
11 (decreasing temperature). ~Eter 50 -thermal cycles, 12 thermal energy for storage ir- the modified ibers was 13 32 . 8 calories/gram and for release 34 . 3 calories/gram a-t 14 -tMe same tempera-ture in-tervals for lleating and cooling.

lG Incorporation of Polyethylene Glycol ~ .
17 ( av. molecular ~t . o 3350 ) 18 into l-lollow Rayon Fibers 19 Hollow rayon fibers were treated with -the same 20 concentratioll of Carbowax 3350*as in Example 3, cooled, 21 dried, and condl tioned, as in Example 1, to produce a 22 modified fiber containing 11.3 grams of Carbowax 3350* per 23 gram of rayon iber. Evaluation of the modified hollow 24 :fibers by calorimetry for up -to 50 hea-ting and cooling 25 cycles at -40 to -~80C, lndicated that their thermal 26 energy available for s torage a-f-ter 1 hea-ting and cooling 27 cycle was 43. 5 calories/gram in -tlle temperature interval 28 of 42 to 77C and for release 49. 6 calories/gram in the 29 temperature interval of 17 to 52C. 7~f ter 50 tllermal 30 cycles a-t tlle same temperature intervals, thermal energy 31 for storage in tl-e modified flbers was 43.3 calories/gram 32 and for release ~7.1 calories/grani.
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1 EX~MPLE 5 2 Incorporation of Polyethylene Glycol 3 (av. molecular wt. 1000) into ~lollow 4 Rayon Fibers A 57 . ~ aquæous solu-tion of poly~thylene glycol 6 (Carbowax 1~00~ was aspirated tllrougl- hollow rayon fibers 7 under reduced pressure, cooled, dried, and conditioned, 8 as in Example 1, to produce a modifled hollow fiber 9 containing 10.8 grams of Carbo~ax lOOO*per g~am of rayon fiber. Wl-en the modified fibers were evaluated by 11 calorimetry for up to 50 thermal cycles at -40 to +60C
12 their ~thermal energy avallable for storage after 13 heating cycle was 43.2 calories/gram in the tempera-ture 1~ interval of 17 to 52C and for release after 1 cooling cycle 41.8 calories/gram in the temperature interval of 16 -3 to ~2C. ~fter 50 thermal cycles, thermal energy for 17 storage in the modified ibers was 43.5 calories/gram and 1~ for release ~1.6 calories/gram at -the same temperature 19 intervals for heating and cooling.

21 Incorporation of Polyethylene Glycol 22 (av. nlolecular w-t. 400) into l-lollow 23 Poly~ x~ene Fibers Z~l A 57.1% solution of polyethylene glycol (Carbo~lax ~00) was aspirated through hollow polypxopylene fibers 26 under reduced pressure, cooled, dried, and condi-tioned, 27 as in Example 1, to produce a modified hollow fiber 28 containing 1.2 grams oE Carbowax 400* per gram of 29 polypropylene fiber. Evaluation oE ~he modified fibers by calorimetry for up to 10 heating and cooling cycles at 31 -~0 to -~60C indica-ted ttlermal storage values of 28. 5 32 calories/gram (tempera-ture interval: -28 to -~12C) *Trade Mark , "

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1 and release values of 24.9 calories/gram (temperature 2 interval: -A8 to -8C) after 1 heating and cooling cycle, 3 respectively. After 10 -thermal cycles, the thermal 4 storage and release values at the same temperature intervals were respec-tively 28.1 calories/gram and 2~.7 6 calories/gram.

8 Incorporation of Polyethylene Glycol 9 (av. molecular wt. of 600) into _ Cotton ~abric 11 100~ desized, scoured, and bleached cotton 12 printcloth (3.15 oz/yd2; thread count 84 warp x 76 flll;
13 1 ft. wide x 9 ft. long) was immersed in a 50% aqueous 14 solution of polyethylene glycol (Carbowax 600*) at 25C, then excess solution removed by running the treated 16 fabric through a squeeze roller to a wet pickup of 100%.
17 Two one ft.2 samples were removed from the treated 18 fabric, one of which was placed on a flat surface and 19 allowed to air-dry overnight for 24 hours at 15C, and the other dried for 85 seconds at ~5C in a Mathis 21 Laboratory Dryer (one that stimulates commercial drying 22 without liquid migration). The drying p~ocedure is to 23 effect solidification of the phase-change material on the 24 fabric. After drying, each treated fabric was conditioned, as described as in Example 1, to give a 26 modified fabric containing 0.6 grams of Carbowax 600*per 27 gram of cotton fabric. When the modified cotton fabrics 28 were evaluated by thermal analysis at -23 to ~37C, their 29 thermal energy available for storage was 18-20 calorles per gram for 1 or 10 heating cycles, with lit-tle 31 difference in these values for fabrics dried by each 32 method. Similar results were obtained for thermal energy 33 available for release (16-18 calories per gram for 1 or 34 10 cooling cycles). In contras-t, the unmodified cotton 35 fabric had thermal storage values of 11-12 ~ T~3~

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, ~ t7 1 calories per gram and release values of 10.5-11.8 2 calories per gram in the same temperature intervals, due 3 only to the specific heat of the unmodified fibers.

Incorporation of LiN03.3H20 into 6 Hollow Rayon Fibers 7 Pure LiN03.3H20 was melted at 30C, ~hen aspirated 8 under reduced pressure into hollow rayon fibers that were 9 subsequently cooled, dried, and conditioned, as in E~ample 1, to produce a modified hollow fiber containing 11 9.5 grams of lithium nitrate trihydrate per gram of rayon 12 fiber. The modified fibers were then evaluated up tQ 50 13 thermal cycles at -40 to ~60C. Their thermal energy 14 available for storage after l, 10, and 50 heating cycles was respectively 72.4, 74.7 and 37.4 calories/gram, and 16 for thermal release after 1, 10, and 50 cooling cycles, 17 53.1, 42.2, and 9.8 calories/gram, with progressive 18 supercooling occurring by 50 cycles. Temperature l9 intervals for all heating cycles for maasuring thermal storage were 17 to 42C, while the temperature interval 21 chosen for cooling cycles varied, and was -1 to 9C, -7 22 to ~2C, and ~22 to 17C for 1, lO and 50 cooling cycles, 23 respectively.
24 Although the rayon/lithium nitrate trihydrate system lost its thermal effectiveness on prolonged 26 cycling, it was superior to either the pure LiN03.3H20 27 alone or to this phase change material incorporated into 28 the polypropylene hollow fiber. After 1 and 10 cycles 29 thermal storage values ~or the pure LiN03.3H20 were 65.8 and 23.0 calories/gram (1 and 10 cycles) thermal storage 31 values for the pure LiN03.3H20 were 65.8 and 23.0 32 calories/gram (1 and 10 cycles) and 30.5 and 22.1 33 calories/gram (1 and 10 cycles) for the lithium 4~9t;i~59L

l nitrate trihydrate incorporated into the polypropylene 2 fiber at a ratio of 1.9 grams/gram of fiber after 3 cooling, drying and conditioning. On cooling, similar 4 trends were observed. After 1 and 10 cooling cycles, the 5 pure LiNO3.3H2O had thermal storage values of 50.0 and 6 2.3 calories/gram and the LiNO3.3~2O treated fibers 7 corresponding values of 4.7 and ~.2 calories/gram, ths 8 latter due only to the specific heat of the polypropylene 9 fiber. Temperature values varied, particularly with cooling cycles, and generally were measured at intervals 11 reflecting the peak temperature midpoint of 12 crystalization on cooling.

14 Incorporation of Zn~NO3)2.6H2O
into Hollow Rayon Fibers 16 An 89.7~ aqueous solution of Zn(NO3)2.6H2O was 17 incorporated into hollow rayon fibers (38 mm in length) 18 that were cooled, dried, and conditioned, as in Example 19 1, to produce a modified fiber with 15.0 grams of zinc nitrate hexahydrate per gram of rayon fiber. When the 21 modified fibex was evaluated between -40 to ~60C by 22 differential scanning calorimetry, it produced 28.6 23 calories per gram for thermal storage (temperature 24 interval: 22 to 46.6C), and 16.9 calories/gram for thermal release (temperature interval: -3 to 9C) after 1 26 cycle. After 5 thermal cycles, the corresponding thermal 27 storage and release values were 36.6 calories/gram on 28 heating (same temperature interval as 1 heating cycle) 29 and 12.9 calories/gram on cooling (temperature interval:
-3 to ~9C).
31 When the same concentration of the above 32 phase-change material was incorporated into hollow 33 polypropylene fibers, the modified fibers contained 1.4 34 grams of zinc nitrate hexahydrate per gram of polypropylene. On their evaluation by calorimetry, their 7~
~ 20 -1thermal storage values for the 1 and 5 heating cycles 2were respectiv01y, 23.3 and 24.9 calories/gram 3(temperature interval: 22 to 48C) and for thermal 4release after 1 and 5 cycles, 8.2 and 5.7 calories/gram 5(temperature interval: 12 to 20C), with the latter value 6due only to the specific heat of the polypropylene fiber.

8Incorporation of CaC12.6H20/SrC12.6H20 9into Hollow Rayon Fibers 10A 49.4% CaCl2.6H20/1.0~ SrCl2.6H20 aqueous 11soluti~on was aspirated through hollow rayon fibers that 12were dried, cooled, and conditioned, as in Example 1, to 13produce a modified fiber containing 3.2 grams o~ calcium 14chloride hexahydrate/ strontium chloride hexahydrate per 15gram of rayon fiber. When the modified fiber was 16evaluated by calorimetry at -40 to ~60C, it had thermal 17storage values of 11 calories/gram (temperature interval:
1822 to 37C) and release values of 14 calories/gram 19(temperature interval: -8 to +17C) after 1 thermal 20cycle. After 10 heating and cooling cycles, its thermal 21storage value was 17 calories/gram and release value 16 22calories/gram (same temperature interval as 1 cycle).

24Incorporation of 25Na2so4~loH2o/Na2B4o7-loH2o 26into Hollow Rayon F bers 27 A 40~ Na2S04.10H20/10~ Na2B407-10H20 aqueous 28 solution was aspirated through hollow rayon fibers that 29 were dried, cooled and conditioned, as in Example l, to produce a modified fiber containing 9'7~

l 0.1 gram of sodium sulfate hexahydrate/borax per gram of 2 rayon fiber. When the modi~ied fiber was evaluated by 3 calorimetry at -40 to ~60C, it was practically 4 indistinguishable from unmodified hollow rayon fibers in its thermal storage and release properties after 5 6 heating and coolin~ cycles, and axhibited no pronounced 7 endotherms or exotherms (associated with storage and 8 release effects) even after only 1 heating and cooling 9 cycle. Consequently, all phase-~hange materials do not work.

12 Incorporation of 2,2-Dimethyl-1,3-propanediol 13 into Hollow Rayon Fibers 14 Hollow rayon fibers cut from tow (135 mm in length) 1~ were prepared and treated, as in Example 1, with a 50 16 aqueous solution of 2,2-dimethyl-1,3-propanediol (DMP), 17 cooled, dried and conditioned as in Example 1 to produce 18 a modified fiber containing 2.8 grams of DMP per gram of 19 rayon fiber. When the modified hollow fibers were evaluated by thermal analysis for up -to 50 heating and 21 cooling cycles at 7 to 62C, their thermal energy 22 available for storage after 1 heating and cooling cycle 23 was 30.5 calories/gram in the temperature interval of 32 24 to 62C (increasing temperature) and for release 27.2 calories/gram in the temperature interval of 37 to 7~
26 (decreasing temperature). After 50 thermal cycles, 27 thermal energy for storage in the modified rayon fibers 28 was 29.5 calories/gram and for release 26.~ calories/gram 29 at the same temperature intervals for heating and cooling. In contrast, unmodified hollow rayon fibers 31 after 1 heating and cooling cycle exhibited fairly linear 32 behavior and had in the same temperature intervals, 33 thermal storage values of 9.3 calories/gram and release 34 values of 8.7 calories/gram, due to only the specific heat of the unmodified fibers.

7~

2 Incorporation of 2,2-Dimethyl-1,3-propanediol 3 into Cotton Fabric -4 100% desized, scoured, and bleached cotton printcloth (3.15 oz/yd2; thread count 84 warp x 76 fill;
6 1 ft. wide ~ 9 ft. long) was immersed in a 50% aqueous 7 solution of DMP, then excess solution removed from the 8 fabric by running the treated fabric through a squeeze 9 rolled to a wet pickup of 100~. Two 1 ft2 samples were removed from the treated fabric, one of which was placed ll on a flat surface and allowed to air-dry overnight for 24 12 hours at 15C, and the other dried for 85 seconds at 75C
13 in a Mathis Laboratory Dryer ~one that simulates 14 commercial drying without liquid migration). The drying procedure is to effect solidification of the phase-change 16 material on the fabric. After drying, each treated 17 fabric was conditioned as described in Example 1 to give 18 a modified fabric containing 0.6 grams of DMP per gram of 19 cotton fabric. When these modified fabrics were evaluated by thermal analysis at 7 to 62C, their thermal 21 energy available for storage was 18-21 calories/gram for 22 1 or 10 heating cycles, with little difference in these 23 values for fabrics dried by each method. Similar results 24 were obtained for thermal energy available ~or release (16-18 calories/gram for 1 or 10 cooling cycles). In 26 contrast, the unmodified cotton fabric had thermal 27 storage values of 8.6-9.1 calories/gram and release 28 values of 7.9-8.1 calories/gram in the same temperature 29 intervals, due only to the specific heat of the unmodified fibers.

31 EXAMPLE 1~

32 Treatment of Non-hollow Rayon Fibers with 33 2,2-Dimethyl-1,3-propanediol__ 3~ Staple rayon fibers (as two-plied yarn, 32-50 mm : :
. .

- :

.
~' ' - ~ .

, 1 staple length; 30.7 mg/m denier) were immersed in excess 2 50~ a~ueous DMP solution, centrifuged for 5 minutes at 3 2080 rpm ~o remove excess DMP, coole~, dried and 4 conditioned, as in Example 12, to produce a modified fiber containing 0.4 grams of DMP per gram of rayon 6 fiber. When the treated rayon fibers were evaluated by 7 thermal analysis for up to 50 heating and cooling cycles 8 at 7 to 62C, their thermal energy for storage after 9 heating and cooling cycle was 15.3 calories/gram in the temperature interval 32 to 62C (increasing temperature) 11 and for release 12.4 calories/gram in the temperature 12 interval of 37 to 7C (decreasing temperature). After 50 13 thermal cycles, thermal energy for storage of the treated 14 rayon fibers was 12.5 calories/gram and for release 11.2 calories/gram at the same temperature intervals for 16 heating and cooling.

18 Incorporation of 19 2-Hydroxymethyl~2-methyl-1,3-propanediol into Hollow Polyprop~lene Fibers 21 Hollow polypropylene fibers were treated, as in 22 Example 12, with a 50% aqueous solution of 23 2-hydroxymethyl-2-methyl-1,3-propanediol (HMP), cooled, 24 dried and conditioned as above to produce a modified fiber containing 0.8 grams of HMP per gram of 26 polypropylena fiber. When the modified hollow fibers 27 were evaluated by thermal analysis for up to 50 heating 28 and cooling cycles at 47 to 102C, their thermal energy 29 available for storage after 1 heating and cooling cycle was 32.7 calories/gram in the temperature interval of 72 31 to 102C (increasing temperature) and for release 28.8 32 calories/gram in -the temperature interval of 77 to 47C
33 (decreasing temperature). After 50 thermal cycles, 34 thermal energy for storage in the modified fibers was 31.7 calories/gram and for release 28.4 calories/gram at 36 the same temperature intervals for heating and cooling.

~4~ 5 2 Treatment of Cotton Fibers with 3 2-Hydroxymethyl-2-methyl-1,3-propanediol 4 - Cotton fibers (as mercerized sewing thread-three plied, 23-32 mm staple length and a denier of 31.8 mg/m) 6 were immersed in excess 50% aqueous HMP solution, 7 centrifuged for 5 minutes at 2080 rpm to remove excess 8 HMP, cooled, dried and conditioned as in Example 12 to 9 produce a modified fiber containing 0.7 grams of HMP per gram of cotton fiber. When the treated cotton fibers 11 were evaluated by thermal analysis for up to 50 heating 12 and cooling cycles at 47 to 102C, their thermal energy 13 for storage after 1 heating and cooling cycle was 27.5 14 calories/gram in the temperature interval 72 to 102C
(increasing temperature) and for release 23.4 16 calories/gram in the temperature interval of 77 to 47C
17 (decreasing temperature). After 50 thermal cycles, 18 thermal energy for storage of the treated cotton fibers 19 was 25.3 calories/gram and for release 23.2 calories/gram at the same temperature intervals for heating and 21 cooling. In contrast, untreated cotton fibers after 22 heating and cooling cycle exhibited fairly linear 23 behavior and had in the same temperature intervals, 24 thermal storage values of 10.0 calories/gram and release values of 8.9 calories/gram due to the specific hea-t of 26 the unmodified fibers.

28 Treatment of Cotton Fibers with 29 2 Amino-2-meth~l-1,3-propanediol Cotton fibers (as mercerized sewing thread-three 31 plied 25-32 mm staple length and a denier of 31.8 mg/m) 32 were immersed in excess 50~ aqueous 33 2-amino-2-methyl-1,3-propanediol (AMP), excess AMP

.
- : , . -.

s'~

1 removed and the fibers cooled, dried and conditioned as 2 in Example 16 to produce modified cotton fibers 3 containing l.l grams of AMP per gram of cotton fiber.
4 ~hen the treated cotton fibers were evaluated by thermal analysis for up to 50 heating and cooling cycles at -3 to 6 102C, their thermal energy for storage after 1 heating 7 and cooling cycle was 37.8 calories/gram in the 8 temperature interval 72 to 102C (increasing temperature) 9 and for release 20.0 calories/gram in the temperature interval of 92 to 52C (decreasing temperature). After 11 50 thermal cycles, -thermal energy for storage of the 12 treated cotton fibers was 30.2 calories/gram and for 13 release 18.6 calories/gram at the same temperature 14 intervals for heating and cooling.

16 Incorporation of Pentaerythritol into 17 ~ollow Rayon Fibers 18 ~ollow rayon fibers cut from tow (135 mm in length) 19 were prepared and treated, as in Example 12, with a 30%
aqueous solution of pentaerythritol (PET), cooled, dried 21 and conditioned, as in Example 12, to produce a modified 22 fiber containing 1.2 grams of ~ET per gram of hollow 23 rayon fiber. When the modified hollow fibers were 24 evaluated by thermal analysis for up to 10 heating and cooling cycles at 152 to 207C, their thermal energy 26 available for storage after 1 heating and cooling cycle 27 was 39.5 calories/gram in -the temperature interval of 177 28 to 207C (increasing temperature) and for release 34.0 29 calories/gram in the temperature interval of 182 to 152C
(decreasing temperature). Af-ter 50 thermal cycles, 31 thermal energy for storage and release in the modified 32 hollow rayon fibers was indistinguishable from the 33 untreated hollow rayon fibers.

~ ~9~7 -- ~6 --2 Incorporation of Polyethylene Glycol 3 (av. molecular wt. 600) into Cot-ton Fabrlc by its 4 Reaction with Crosslinking Agent 100-~ desized, scoured and bleached cotton 6 printcloth (3.7 oz/yd2; thread count 80 warp ~ 80 fill;
7 10 in. wide x 24 in. long) was immersed in an aqueous 8 solution containing by weight 50~ polyethylene glycol 9 (Carbowax 600~, 10% dihydro~ydimethylol-ethylene urea (DMDHEU) 3~ mixed catalyst (MgCl2/citric acid) at 25C, 11 then excess solution removed by running the treated 12 fabric through a squeeze roller at S0 lb. pressure to a 13 wet pickup of 100%. The fabric was then mounted on a pin 14 frame, dried 7 min. at 60C in a force-draft oven, then cured an additlonal 3 min. at 160C. The traated fabric 16 was subsequently given a conventional machine laundering 17 and tumble drying (warm/cold cycle ~or 10 min. wi-th 18 commercial phosphate detergent and dried for 15 mins. on 19 normal drying cycle) or alternatively washed for 20 mins.
at 50C with running tap water and liquid detergent prior 21 to tllmble drying. The resultant fabric had a weight gain 22 or add-on of 40~0% (0.4 gms. per gram of fiber~. If the 23 crosslinking agent were not employed, the polyethylene 24 glycol would readily wash off on exposure to excess water. The modified fabric was conditioned at standard 26 atmospheric conditions (65~ RH/70F), and evaluated by 27 thermal analysis at -3 to ~37C. It had thermal energy 28 available for storage of 16.4 calories per gram for 1 or 29 10 heating cycles, with little difference in these values aftsr the ini-tial cycle. Simllar results were obtained 31 for thermal energy available for release at -17 -to ~23C
32 (14.9 calories per gram for 1 or 10 cooling cycles). In 33 contrast, the unmodified cotton had thermal storage 34 values of 9.6 calories per gram and ~t~

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1~ 79 75L~L

1 releas~ values of 9.7 calories per gram in the same 2 temperature intervals, due only to the specific heat of 3 the unmodified fabric.

Attempts to Incorporate Polye-thylene Glycol into 6 Cotton Fabric Using Other Crosslinking A~__ts 7 Cotton printcloth (as in Example 19) was padded 8 with 50~ aqueous polyethylene glycol (Carbowax 1,000~
9 containing 3% magnesium chloride/citric acid as the 10 catalyst with the following crosslinking agen-ts: with 11 (a) 10~ formaldehyde; (b) 10% diisopropyl carbamate; and 12 ~c) 10~ dimethylolethylene urea (DMEU). In aach instance 13 the fabrics were treated (dried and cured) as in Example 14 lA, bu-t little reaction took place between the 15 polyethylene glycol and these crosslinking agents as 16 evidenced by the very low add-ons (3-5~ or 0.03-0.05 gm 17 per gram of fiber). Thermal analyses of these fabrics 18 showed them to essentially be no different than the 19 untreated cot-ton fabrics with regard -to their thermal storage and release fabric properties, with their heat 21 content due only to the specific heat of the fiber.

23 Attempts to Incorporata Higher Molecular 24 Weight Polyethylene Glycols into Cotton Fabrics Cotton prin-tcloth (as in Example 19) was padded 26 with various concentrations of aqueous polyethylene 27 glycols (M.W. 3,350 and M.W. 8,000), DMDHEU and a 28 magnesium chloride/citric acid catalyst (30% by wt. of 29 the crosslinking agent). The ~ollowing combinations were used: 30-50~ aqueous polyethylane glycol (av. mol. w-t.
31 8,000), 10% DMDHEU, 3~ magneslum chloride/citric acid 32 catalyst, 50% aqueous polye-thylene glycol (av. mol. wt.

~ .

, ~, . . ~ . . .. . . . . . . . ..
,: :
- , ~ '; ' ' 9~75~

1 3,350), 10 to 15-~ DMDTIEU, 3.0 to 4.5-~ magnesium 2 chloride/citric acid catalyst. In each instance, -the 3 fabric was treated (dried and cured) as in EY~ample 19, ~ but only moderate weight gains were achieved (B-17~ or 0.08-0.17 gm per gram of fiber) after laundering, 6 indicating that not enough reaction had taken place to 7 insolubilize the polymers. In all instances, the 8 modified fabrics were essentially unchanged in their 9 thermal storage and release characteristics, i.e., the same as the unmodified cotton fabrics from which they 11 were derived.

13 Incorporation of Polyethylene Glycol (Average 14 Molecular Weight 1,000) into Wool and into Polyester Fabrics by its Reaction with Crosslinking Agents 16 Worsted wool fabric (5.4 oz/yd2; thread count 55 17 warp x 45 fill; 10 in. wide x 10 in. long) was immersed 18 in an aqueous solution containing by weight 50%
19 polyethylene glycol (Carbowax 1000~, 12~
dihydroxydimethylolethylene urea (DMDHEU), 3.6% mixed 21 catalyst (MgC12/citric acid) at 25C, then excess 22 solu-tion removing by running the treated fabric through a 23 squeeze roller at 50 lb. pressure to a wet pickup of 24 94%. The fabric was dried, cured and given 1 laundering as in Example 19, and had an add-on or weight gain of 26 48.0% (0.48 gm per gram of fiber) after drying and 27 conditioning. As previously indicated, the polye-thylene 28 glycol will wash off readily in water if it is not 29 crosslinked. The resultant fabric was evaluated by thermal analysis at -3 to +37C, and had thermal energy 31 available for storage of 19.5 calories per gram for 1 or 32 10 heating cycles, with little difference in -these values 33 after the initial cycle. Similar results were obtained 34 for thermal energy available for release at -~17 to -23C
(16.3 calories per gram for 1 or 10 i~ r . ~ ` ' ~, "", i, Jf;

. .

~.~'7~7~

1 cooling cycles). In contrast, the unmodified wool had 2 thermal storage values of 12.5 calories per gram and 3 release values of 12.8 calo~ies per gram ln the same 4 temperature intervals, due only to the specific heat of the unmodified fabric.
6 Treatment of heat set polyester fabric (3.6 oz/yd2;
7 thread count 67 warp x 57 fill; 10 in. wide x 10 in.
8 long) under identical conditions as that for the wool 9 above (only difference was a 776 we-t pickup), produced a modified fabric with a weigh-t gain of 42.9% (0.429 gm per 11 gram of fiber) that had thermal storage values of 12.7 12 calories/gram ~or 1 or 10 heating cycles and thermal 13 release values of 13.1 calories/gram for 1 or 10 cooling 14 cycles (same ranges as the wool fabrics~. In contrast, the unmodified polyester had thermal storage values of 16 9.3 calories/gram and thermal release values o~ 9.7 17 calories/gram for 1 or 10 cycles due only -to the specific 18 heat of the unmodified fabric.

Incorporation of Polyethylene Glycol (av. mol. wt. ~00 21 into Cotton Fabrics by i-ts Reaction wi-th Crosslinking 22 Agents to Produce Modified Fabrics Having Improved 23 (Except Thermal Storage and Release) Properties 24 Cotton printcloth (as in Examplo 19) was immersed separately into two different aqueous solutions (by wt.) 26 of Carbowax 600~ (a) 35% polyethylene glycol, 7~
27 dihydroxydimethylolethylene urea (DMDHEU), 2.1~ mixed 28 catalyst (MgC12/citric acid); and (b) 50% polyethylene 29 glycol, 15-~ DMDHEU, and 4.5% mixed catalyst (MgC12/citric acid) at 25C, then excess solu-tion removed by running 31 each of the trea-ted fabrics through a squeeze roller at 32 40 lb. pressure to a wet pickup o~ 100-~. Fabrics were 33 then mounted on pin frames, dried 7 min. at 60C in a 34 force-draft oven, then cured an additional 2 min. at 170C. Bo~h fabrics were washed ~ r~

~ - - . ............... .

-.

75~

1 for 20 mins. at 50C with running ~ap water and liquid 2 detergent prior to tumble drying. After conditioning, 3 the first fabric had a weight of 16.5% while the second 4 fabric had a weight gain of 59~. Neither of the fabrics exhibited any endotherms or exotherms on heating or 6 cooling cycles when evaluated by differential scanning 7 calorimetry and were essentially the same as the 8 untreated cotton fabrics in their thermal storage and 9 release properties; i.e., their heat content was due only to their specific heat. ~owevsr, other textile 11 properties in both treated fabrics were improved relative 12 to untreated cotton printcloth: (a) conditioned wrinkle 13 recovery (warp + fill) angle in the first treated fabric 14 was 292 and 278 in the second treated fabric compared to only 170 for untreated cotton fabric; (b) oily soil 16 release (using a modified Milliken Test Method 17 DMRC-TT-100 in which the fabrics were soiled then washed 18 and their re~lectances values measured) was improved for 19 both treated fabrics (retention of 90 and 86~ of their reflectance for the first and second treated fabrics) 21 relative to the control (only 54~ retention of 22 reflectance); (c) static charge remaining on the treated 23 fabrics at 65% relative humidity (AATCC Test 76-1982) was 24ll,000 and 2,000 (ohms x 108 compared to 91,000 for the 25untreated cotton printcloth).

27Incorporation of Polyethylene Glycol 28(av. mol. wt. 1,450) into Acrylic Fabric by its 29Reaction with Crosslinkin~ Agents Acrylic fleece fabric (5.2 oz/yd2; 18 in x 24 in) 31 was immersed in an aqueous solution containing 50~ aq.
32 polyethylene glycol 1,450, 13~ DMDHEU, 3.9~ mi~ed 33 catalyst (MgCl2/citric acid) at 25C, then excess 34 solution removed as in Example 23 (40 lb. pressure) to give a fabric with a wet pickup of 166-~. The fabric was ~7~3'7~;~

1 subsequently dried on a pin frame for 6 min. at 80C, 2 then cured for 2 min. at 140C. The modified ~abric was 3 then washed and tumble dried (as in Example 19) -to give 4 an add-on or weight gain of 87%. The resultant fabric had thermal storage values of 19.8 cal/g in the range of 6 +2 to +42C on heating and thermal release values of 20.2 7 cal/g in the range of +27 to -13C on cooling, 8 characterized by an endotherm on hea-ting and an exotherm 9 on cooling. In contrast the untreated acrylic fabric has thermal storage values o~ only 11.0 cal/g and thermal 11 release values of 9.6 cal/g in the same temperature 12 ranges.
13 The modified acrylic fabric also possessed superior 14 flex abrasion compared to the untreated acrylic fabric.
When the Stoll flex abrasion of the back sides of both 16 fabrics were measured, the treated fabric lasted 4,650 17 cycles to failure while -the untreated fabric lasted only 18 792 cycles. Residual static charge (tested as in Example 19 23) was also substantially less for the treated fabric (10,070 x 108 ohms) than for untreated fabric (57,000 x 21 îO8 ohms).

23 Incorporation of Polyethylene Glycol 24 (av. molecular wt. 1,000) into Single Knit Jersey T-Shirts 26 (50/50 Cotton/Polyester) 27 by Reaction with Crosslinking Agents and Evaluation 28 of Durability of Finish to Prolonged Laundering 29 50/50 cotton/polyester (ligh-t blue color) single knit jersey T-shirts (4.4 oz/yd2 were immersed in 50% aq.
31 PEG-l,000*/11-~ DMDHEU/3.3% mixed ca-talyst (MgC12/ citric 32 acid) at 25C, excess solutlon removed at 40 lb. pressure 33 (as in Example 23) to a wet pickup o~ 100%. The shirts 34 were draped over pin frames and dried and cured as in 35 previous examples (dried 7 min. at 75C
*Trade Mark ' ' -- . , .
, , ~?4~ t7~

1 and cured 2 min. at 150C). The shirts were machine 2 washed and tumble dried to give modified garments with 3 weight gains of 55% after conditioning. The thermal 4 storage and release values of the treated shirt were on 5 heating (in the range of -3 to +37C) 15.6 cal/g and on 6 cooling (in the range of -17 to +23C) 14.7 cal/g, 7 compared to only 9.8 cal/g and 9.7 cal/g on heating and 8 cooling for untreated shirts laundered and dried once.
9 After 50 machine washings and tumble dryings, the treated shirts still had a weight gain of 37%, and had 11 little if any pilling or surface entanglement of fibers 12 compared to extensive and visually noticeable pilling in 13 untreated shirts that were also laundered and dried 50 14 times. Moreover, the thermal storage and release proper~ties of the treated shirts after 50 launderings 16 were respectively 13.7 cal/g and 13.5 cal/g on heating 17 and cooling in the same temperatures ranges described 18 above. These values were significantly higher than those 19 of untreated shirts laundered 50 times (9.5 cal/g on heating and 9.5 cal/g on cooling) in the same temperature 21 intervals.

23 Incorporation o~ Polyethylene Glycol 24 (av. molecular wt. 1,000) into Glass Fabric by its 26 Reaction with Crosslinking Agents 27 Fiberglas fabric (3.2 oz/yd2) was treated 28 identically as the T-shirts in Example 25 to a wet pickup 29 of 50%, dried 7 min. at 60C and cured 3 min. at 160C, washed in warm water and detergent for 30 min. and 31 air-dried. After conditioning, the treated glass fabric 32 had a weight gain of 21%. Its moisture regain after 12 33 hours was appreciably higher (8.2%) than the untreated 34 glass fabric (0.4~) using standard tes-t methods for this evaluation. Its thermal storage in the ra~ge of g ~ SL~L

1 -3 to +37C was`14.3 cal/g on heating and charac-terized 2 by an endotherm in this range in contrast to the 3 untreated glass fabric whose thermal storage value was 4 only 5.5 caltg in the same range and du~ only to the specific heat of the glass fiber or fabric.

7 Incorporation of Polyethylene Glycol 8 (av. molecular wt. 1,000) 9 into Cotton/Polyester Fabric by its Reaction with Crosslinking Agents at Low Cure Temperatures 11 ~50/50 cotton/polyester printcloth (4.1 oz/yd2) was 12 treated identically as were the T-shirts in Example 25 at 13 40 lb. pressure to a wet pickup of 100~. The fabric was 14 subsequently dried 7 min. at 75C and dried at a low cure temperature of only 110C for 2 min., then machine washed 16 and tumble dried to a wt. gain of 45~ af-ter 17 conditioning. The resultant fabric had a thermal storage 18 value (on heating) of 18.7 cal/g in the range of ~7 to l9 +47C and a thermal release value (on cooling) of 16.8 cal/g in -the range of +17 to -23C. For untreated 21 cotton/polyester printcloth in the same temperature 22 intervals, the thermal storage and release values (due to 23 specific heat o the fiber alone) were respectively on 24 heating 10.1 cal/g and on cooling 9.7 cal/g. Moreover, the treated fabric had improvement in several properties 26 relative to the untreated fabric: (a) flex 27 abrasion-cycles to failure (>5,000 for treated vs. 3,500 28 for untreated); (b) pilling resistance ra-ting with brush 29 pilling apparatus (5.0 for treated vs. 3.3 for untreated, with 5.0 being the best rating); (c) conditioned wrinkle 31 recovery angle-warp + fill directions (279 for treated 32 vs. 247 for untreated); (d) residual static charge in 33 ohms x 108 at 65~ relative humidity (1,800 for treated 34 vs. 39,000 for untreatsd; (e) ~ moisture regain after 12 hrs. ~24.8 for treated vs. 3.5 for untrsated).

' - :~

~.~'7~S~

2 Incorporation o~ Polyethylene Glycol 3 (av. mol. wt. 1,000) into Paper Products by its 4 - Reaction with Crosslinking Agents Commercial paper -towels (reinforced with polyamide 6 fibers in both directions) (2.1 oz/yd2) were treated with 7 the PEG-l,000 with iden-tical compositions as that 8 described in Example 25 to a we-t pickup of 137~, 9 utilizing 30 lb. pressure to remove excess liquid rom the paper. Subsequent drying for 7 min. at 70C and 11 curing~ for 2 min. at 150C producing after washing in 12 warm water and liquid detergent and air~drying to 13 constant weight, a trea-ted paper towel with a wt. gain of 14 39%.
The treated paper towel had a thermal storage value 16 of la.4 cal/g in the range of -3 to +37C (on heating) 17 and a thermal release value of 20.7 cal/g in the range of 18 *22 to -18C (on cooling). In contrast, the untreated 19 paper towel had thermal storage and release values of 11.6 cal/g and 11.0 cal/g, respectively, in the same 21 temperature ranges due only to the specific heat of the 22 cellulosic and polyamide fibers in the towel. After 12 23 hrs. the moisture regain for the treated paper towel was 24 26.5% and only 8.5~ for the untreated paper towel.

26 Incorporation of Polyethylene Clycol 27 (av. mol. wt. 8,000) into Cotton/Polyester 28 Fabric by Reaction with Crosslin~ing Agents 29 Two pieces of 50/50 cotton/polyester printcloth (4.1 oz/yd2) were immersed in (a) 45% aq. polyethylene 31 glycol 8,000/10~ DMDHEU/0.78% mixed catalyst (0.5%
32 ~-toluenesulfonic acid-0.25~ MgC12-0.03% citric acid) and 33 (b) 45~ aq. PEG~8,000/10% DMDHEU at 30C, *Trade Mark r;., 5 ' ' ' ' ' ' ' ' ~, , .
' ~ .' .' '' , ~,5Y~ 3~;i''S~L

1 put through squeeze rollers at 40 lb. pressure to a wet 2 pickup of 90%, then dried 5 min. at 85C and cured 2 min.
3 at 140C. A~ter washing in hot water (60C) and liquid 4 detergent and tumble drying, the first fabric had a weight gain of 43% and the second fabric did not retain 6 the polyol and had no weight gain.
7 The thermal storay0 value of the first fabric (on 8 heatingj in the temperature range of 32-77C was 20.0 9 cal/g and its thermal release value (on cooling) in the temperature range of 47 to 7C was 18.5 cal/g, and 11 characterized by sharp endoth0rms on heating and sharp 12 exotherms on cooling. In contrast, the second fabric 13 (one not treated in the presence of an acid catalyst) in 14 the same temperature intervals exhibited thermal storage values~ of 12.3 cal/g and thermal release values of 11.3 16 cal/g due only to the specific heat of the untreated 17 fabric.

19 Incorporation of Polyethylene Glycol (av. mol. wt. 20,000) into Acrylic Fleece 21 Fabric by Reaction with Crosslinking Agents 22 Acr~lic fleece fabric (5.2 oz/yd2) was immersed in 23 (a) 40~ aq. polyethylen0 glycol 20,000/10~ DMDHEU/0.76 24 mixed catalyst (0.5% ~-toluenesulfonic acid-0.25-~
MgC12-0.01% citric acid), put through squeeze rollers a-t 26 40 lb. pressure to a wet pickup of 206%, then dried 5 27 min. at 85C and cured 2 min. at 140C. After washing in 28 hot water (60C) and liquid detergent and drying in a 29 force draft oven to constan-t weight, the modified acrylic fabric had a weight gain after conditioning of 89~.
31 Its thermal storage value (on heating) in the 32 temperature range of 32~77C was 25.6 cal/g and its 33 -thermal release value (on cooling) in the temperature 34 range of 57 to 17C was 23.2 cal/g, and charact0rized '' ~, . .
' 1 by sharp endotherms on heating and sharp exotherms on 2 cooling. In contrast, untreated acrylic fabric in tha 3 same temperature intervals exhibited thermal storage 4 values of 11.6 cal/g and thermal release values of 11.5 cal/g due only to the specific heat of the untreated 6 fabric. Percent reflectance values of the treated fabric 7 (as in Example 23) were 96~ after soiling and one 8 laundering comparad to only 65~ for the untraated fabric 9 under comparable conditions.

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Claims (39)

1. A process for producing temperature adaptable non-hollow fibers which store heat when the temperature rises and release when the temperature decreases, wherein said fibers are selected from the group consisting of wood pulp, paper, cotton, rayon, wool, polyamide, polyester, polypropylene, acrylic, glass, and blends thereof, comprising:
applying polyethylene glycol to said fiber in an amount of at least 0.15 grams polyethylene glycol per gram of fiber; and thereafter heating said fibers at a temperature of about 100°-170°C for a sufficient time to cross-link said polyethylene glycol on said fibers to such a degree that said polyethylene glycol becomes water insoluble but wherein said cross-linkage is not so great as to inhibit the ability of said polyethylene glycol to change phases during subsequent raising and lowering of temperatures.

2. The process of claim 1 wherein said polyethylene glycol is applied in an amount of at least 0.25 grams polyethylene glycol per gram of fiber.

3. The process of claim 1 wherein said fibers are textile fibers, and said polyethylene glycol is applied to said fibers in an amount of 0.15-1.0 grams polyethylene glycol per gram of fiber.

4. The process of claim 1 wherein said fibers are textile fibers, and said polyethylene glycol is applied to said fibers in an amount of about 0.25-0.50 grams polyethylene glycol per gram of fiber.

5. The process of claim 2 wherein said temperature is about 100°-130°C.

6. The process of claim 4 wherein said temperature is about 100°-130°C.

7. The process of Claim 5 wherein said polyethylene glycol is applied to said fibers from an aqueous solution containing a trifunctional or greater functionality cross-linking agent.

8. The process of claim 6 wherein said polyethylene glycol is applied to said fibers from an aqueous solution containing a trifunctional or greater functionality cross-linking agent.

9. The process of claim 7 wherein said cross-linking agent is dihydroxydimethylol ethylene urea.

10. The process of claim 8 wherein said cross-linking agent is dihydroxydimethylol ethylene urea.

11. The process of claim 9 wherein said polyethylene glycol has a molecular weight of greater than 1500, and wherein said solution contains p-toluenesulfonic acid.

12. The process of claim 10 wherein said polyethylene glycol has a molecular weight of greater than 1500, and wherein said solution contains p-toluenesulfonic acid.

13. The process of claim 11 wherein said polyethylene glycol-impregnated fibers have improved properties as to soil release, durable press, resistance to static charge, abrasion resistance, pilling resistance and water absorbency.

14. Temperature-adaptable non-hollow textile fibers which store heat when the temperature rises and release heat when the temperature decreases, said fibers impregnated with a phase-change or plastic crystalline material which is chemically and physically compatible with said fibers, said material being present in an amount effective to cause said fibers to store heat when the temperature rises and release heat when the temperature decreases.

15. The fibers of claim 14 wherein said fibers are selected from the group consisting of cotton, rayon, wool, polyamide, polyester, polypropylene, acrylic, glass, and blends thereof.

16. The fibers of claim 14 wherein said phase-change material is selected from the group consisting of congruent inorganic salt hydrates and cross-linked polyethylene glycols, and wherein said plastic crystalline material is polyhydric alcohol.

17. The fibers of claim 15 wherein said phase-change material is selected from the group consisting of congruent inorganic salt hydrates and cross-linked polyethylene glycols, and wherein said plastic crystalline material is polyhydric alcohol.

18. The fibers of claim 16 wherein said phase-change material is selected from the group consisting of calcium chloride hexahydrate in admixture with strontium chloride hexahydrate, lithium nitrate trihydrate, and zinc nitrate hexahydrate, and wherein said plastic crystalline material is selected from the group consisting of pentaerythritol, 2,2-dimethyl-1,3-propanediol,2-hydroxymethyl-2-methyl-1, 3-propanediol, and amino alcohols.

19. The fibers of claim 17 wherein said phase-change material is selected from the group consisting of calcium chloride hexahydrate in admixture with strontium chloride hexahydrate, lithium nitrate trihydrate, and zinc nitrate hexahydrate, and wherein said plastic crystalline material is selected from the group consisting of pentaerythritol, 2,2-dimethyl-1,3-propanediol,2-hydroxymethyl-2-methyl-1, 3-propanediol, and amino alcohols.

20. The fibers of claim 16 wherein said phase-change material is cross-linked polyethylene glycol, wherein the degree of cross-linking is sufficient to make said material water insoluble and to maintain the ability of said material to change phases upon heating and cooling, and further wherein said impregnated fibers have improved properties as to soil release, durable press, resistance to static charge, abrasion resistance, pilling resistance, and water absorbency.

21. The fibers of claim 17 wherein said phase-change material is cross linked polyethylene glycol, wherein the degree of cross-linking is sufficient to make said material water insoluble and to maintain the ability of said material to change phases upon heating and cooling, and further wherein said impregnated fibers have improved properties as to soil release, durable press, resistance to static charge, abrasion resistance, pilling resistance, and water absorbency.

22. The fibers of claim 14 wherein said material is present in an amount of about 0.25-0.50 grams per gram of fiber.

23. Non-hollow textile fibers impregnated with at least 0.15 grams of cross-linked polyethylene glycol per gram of fiber, wherein the degree of cross-linking makes said polyethylene glycol water insoluble, said cross-linked polyethylene glycol being present in an amount effective to cause said fibers to store heat when the temperature rises and release heat when the temperature decreases.

24. The fibers of claim 23 wherein said polyethylene glycol is present in an amount of at least 0.25 grams per gram of fiber, and where the degree of cross-linking is sufficient to permit said polyethylene glycol to change phases upon heating and cooling.

25. The fibers of claim 23 wherein said fibers are selected from the group consisting of cotton, rayon, wool, polyamide, polyester, polypropylene, acrylic, glass, and blends thereof.

26. The fibers of claim 24 wherein said fibers are selected from the group consisting of cotton, rayon, wool, polyamide, polyester, polypropylene, acrylic, glass, and blends thereof.

27. The fibers of claim 23 wherein said impregnated fibers have improved properties as to soil release, durable press, resistance to static charge, abrasion resistance, pilling resistance and water absorbency.

28. The fibers of claim 24 wherein said impregnated fibers have improved properties as to soil release, durable press, resistance to static charge, abrasion resistance, pilling resistance and water absorbency.

29. The fibers of claim 23 wherein said polyethylene glycol has a molecular weight o greater than 1500.

30. The fibers of claim 24 wherein said polyethylene glycol has a molecular weight of greater than 1500.

31. The fibers of claim 28 wherein said fibers are selected from the group consisting of cotton, rayon, wool, polyamide, polyester, polypropylene, acrylic, glass, and blends thereof.

32. Non-hollow cellulosic fibers impregnated with at least 0.15 grams of cross-linked polyethylene glycol per gram of fiber, wherein the degree of cross-linking makes the polyethylene glycol water insoluble, said cross-linked polyethylene glycol being present in an amount effective to cause said fibers to store heat when the temperature rises and release heat when the temperature decreases,

33. The fibers of claim 32 wherein said polyethylene glycol is present in an amount of at least 0.25 grams per gram of fiber, and wherein the degree of cross-linking permits the polyethylene glycol to change phases upon heating and cooling.

34. The fibers of claim 32 wherein said fibers are paper or wood pulp fibers.

35. The fibers of claim 33 wherein said fibers are paper or wood pulp fibers.

36. The fibers of claim 32 wherein said impregnated fibers have improved properties as to soil release, durable press, resistance to static charge, abrasion resistance, pilling resistance and water absorbency.

37. The fibers of claim 33 wherein said impregnated fibers have improved properties as to soil release, durable press, resistance to static charge, abrasion resistance, pilling resistance and water absorbency.

38. The fibers of claim 32 wherein the molecular weight of said polyethylene glycol is greater than 1500.

39. The fibers of claim 33 wherein the molecular weight of said polyethylene glycol is greater than 1500.