Method of imparting durable water repellency to a woven or nonwoven fabric and water repellent composition

Abstract

The present invention relates to a method and to a water repellency composition for imparting durable water repellency to a woven or nonwoven fabric. The composition comprises - an aqueous solvent comprising at least 80 w / w% of water and 20 w / w% or less of a water-soluble or water-miscible organic molecule comprising at least two functional OH groups, - 0.1 to 40 w / w% of an acrylate having formula 1: wherein A 1 is H or CH3, and A 2 is a C1-C 30 linear or branched, saturated or unsaturated hydrocarbon optionally having a cycloaliphatic or aromatic ring, the acrylate being dissolved, emulsified or dispersed in the aqueous solvent, and - a polyisocyanate having at least 3 cross-linkable isocyanate groups.

Description

[0001] This application is a divisional application of the application filed on April 8, 2022, with application number 202280028780.3 and entitled "Method and Waterproof Composition for Imparting Durable Waterproof Properties to Woven or Nonwoven Fabrics". Invention Field

[0002] The present invention relates to a method for imparting durable water resistance to woven or nonwoven fabrics, a composition for imparting durable water resistance to woven or nonwoven fabrics, and woven or nonwoven fabrics treated with said composition. Background Technology

[0003] Methods for imparting durable water resistance to woven or nonwoven fabrics are known in the art. To date, providing durable water resistance to fabrics has relied on highly efficient and very durable fluorocarbon-based treatments. However, byproducts such as fluorosurfactants and derivatives based on C8 and C6 fluorosurfactants are toxic and persistent in the environment, and their combination makes them unacceptable despite their superior performance. Many fluorine-free coatings available today have short lifespans. Waterproof rain covers functionally degrade into windproof covers long before the clothing itself wears out.

[0004] JP2020153057 describes the vinyl-based polymerization of a specific divinyl compound with a molecular weight of 600 or higher, involving the chemical bonding of the vinyl polymer to a polyester fabric. An additional film is applied, comprising a fluorinated copolymer polymerized with a perfluoroalkyl group having six or fewer carbon atoms, or an acrylic monomer. The additional film is crosslinked with a melamine resin.

[0005] EP3919673 describes a special fabric surface that resembles the surface of a lotus leaf to simulate its water-repellent properties. This artificial lotus-shaped surface can be treated with commonly known water-repellent agents.

[0006] WO2016 / 000831 describes a composition for application to textiles to impart water resistance, wherein three different acrylate monomers (one of which contains fluorine) are polymerized into a polyacrylate by means of an azo initiator. In addition to the resulting polyacrylate, the composition also includes a wax. Summary of the Invention

[0007] This invention provides a method and fiber treatment compositions for imparting durable water resistance to woven or nonwoven fabrics. These compositions impart excellent wash-resistant water resistance to fiber products without the need for fluorine incorporation or the use of siloxanes, isocyanates, or melamine synergists. This method for imparting durable water resistance to woven or nonwoven fabrics produces a highly durable and sustainable water-resistant coating on the fabric, which remains unaffected even after 100 or more machine washes.

[0008] Therefore, the method includes the following steps:

[0009] i) Treating the fabric with an aqueous composition, the composition comprising:

[0010] a. An aqueous solvent comprising at least 80 w / w% water and 20 w / w% or less of a water-miscible organic solvent comprising at least two functional OH groups, and

[0011] b.0.1-40 w / w% has Equation 1: acrylates, wherein A 1 It is H or CH3, and A 2 C1-C can have alicyclic or aromatic rings. 30 The acrylate is a straight-chain or branched, saturated or unsaturated hydrocarbon, dissolved, emulsified or dispersed in an aqueous solvent.

[0012] ii) Heat the treated fabric to 120-200°C.

[0013] According to the method of the present invention, the water-miscible solvent participates in the chemical reaction with the acrylate through its functional OH groups.

[0014] A (trans) esterification reaction is initiated between the water-miscible solvent molecule and the acrylate via heat treatment step ii). A covalent COC bond is formed between one of at least two OH groups of the water-miscible solvent molecule and the oxygen atom of the C=O group of the acrylate of Formula 1. Since the water-miscible solvent molecule has at least two functional OH groups, the acrylate acquires a functional OH group, enabling the ester to bond to the fabric fibers via a hydrogen bridge through this OH group. Therefore, a "functional OH group" refers to a group capable of forming the COC bond. Conditions are chosen such that the above reaction can be carried out, for example, at an acidic pH.

[0015] Unbound by any scientific explanation, transesterification can also occur, in which aqueous solvent molecules are converted into acrylate molecules via the CH2=C(A) group. 1 COO is partially esterified, and A 2 Partially covalently attached to the terminal OH group. In the latter case, A 2 Partially attached to the fabric fiber via hydrogen bridges of its newly acquired terminal OH groups. Esterification reactions can also lead to both incomplete and complete esterification processes, both resulting in the fiber acquiring hydrophobic A atoms bonded to it via hydrogen bridges. 2 Partial. Since the result of heat treatment is that part A2 bonds with the fabric, this step is also considered a curing step.

[0016] However, it is clear that the compositions of the present invention do not include acrylate polymers, i.e., polymers comprising, for example, a plurality of acrylate monomers polymerized together using an azo initiator, particularly three or more acrylate monomers. Furthermore, it is clear from the above definition that the acrylates are free of fluorine groups.

[0017] The suitable acrylates defined above for step i)b are known in the art, such as the Unidyne XF series (Daikin, Japan).

[0018] Heat treatment produces a fabric whose fibers include hydrophobic A molecules stably bonded thereto via hydrogen bridging. 2 This results in very strong and sustainable waterproofing.

[0019] Water-miscible solvents may include more than two functional OH groups, but preferably two functional OH groups. Therefore, water-soluble aqueous solvents are preferably organic water-miscible solvents, more preferably selected from the group consisting of: ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol dimethyl ether, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol, tripropylene glycol monomethyl ether, polypropylene glycol, and hexanediol. Tripropylene glycol is the most preferred.

[0020] The aqueous solvent preferably includes at least 0.1 w / w%, more preferably at least 0.2 w / w%, of a water-miscible solvent.

[0021] The aqueous solvent preferably includes 90-99.9 w / w% water and 0.1-10 w / w% water miscible solvent, more preferably 95-99.8 w / w% water and 0.2-5 w / w% water miscible solvent, or 95-99 w / w% water and 1-5 w / w% water miscible organic solvent.

[0022] The composition preferably includes 0.2-20 w / w%, more preferably 0.5-10 w / w%, and even more preferably 1-6 w / w% acrylate.

[0023] To achieve optimal waterproofing, the surface tension of the coating should be approximately 25 mN / m. 2 Therefore, A 2 Partially preferably alkyl. Acrylate A 2 The portion preferably has 12 to 24 carbon atoms, more preferably 12 to 21 carbon atoms, and even more preferably 18 carbon atoms. The A-CH2- portion imparts approximately 31 mN / m 2 The terminal -CH3 imparts 22 mN / m2 This means that a higher -CH3 content will result in a coating with lower surface tension and therefore stronger water resistance. A higher -CH3 content can be achieved by increasing the number of branches in the hydrocarbon chain. Therefore, although A 2 The part can be a straight chain, but the part is preferably branched.

[0024] It has been found that the coating applied to the fabric according to the method described above remains very stably adhered to the fabric. The fabric was observed to remain completely intact during 100 wash cycles, followed by drying in a rotary dryer operating with a conventional drying procedure (i.e., involving heating). However, it was observed that when drying was performed without the addition of heating (so-called "line drying"), the coating began to wear off after approximately 10 wash cycles.

[0025] The coating can be further improved by including a polyisocyanate having at least three crosslinked isocyanate groups in the aqueous composition. Surprisingly, the presence of the polyisocyanate resulted in a significant increase in coating stability, with no significant wear observed after 30 wash cycles followed by line drying. As a result of the aforementioned transesterification reaction, water-miscible solvent molecules and the functional OH groups of the acrylate, including functional OH groups, and the A2 moiety with functional OH groups obtained in this manner are covalently bonded to the polyisocyanate, creating a crosslinked network of hydrophobic carbohydrate moieties. This network is formed by the interlinking of polyisocyanate molecules covalently linked to each other with the functional OH groups of the water-miscible solvent molecules. Because these molecules include two or more functional OH groups, these functional groups link the polyisocyanate molecules together, form hydrogen bridges with the fabric fibers, and provide functional groups to the acrylate of the A2 moiety.

[0026] Polyisocyanates can be, for example, aromatic or aliphatic, and suitable polyisocyanates are known in the art. Since polyisocyanates are in aqueous compositions, such as water-based compositions, they are preferably blocked, for example by blocking groups known in the art, such as phenol, nonylphenol, methyl ethyl ketone oxime (MEKO), alcohols, α-caprolactam, amides, imidazoles, or pyrazoles. JP2020007657 describes a fiber treatment composition comprising a waterproofing agent and such a blocked polyisocyanate. To make the blocked polyisocyanate active, i.e., unblocked, water is first removed, for example by drying, followed by a subsequent heating step. Very attractive isocyanates are trimers based on aliphatic hexamethylene-1,6-diisocyanates, particularly HDI trimers (Kowa, NY, US).

[0027] The weight ratio of acrylate to isocyanate is 100:5-100, preferably 100:30-80, more preferably 100:50-70, and most preferably 100:60. A relatively high acrylate:isocyanate ratio was found to produce the most stable coating.

[0028] In step ii), heating is preferably carried out at 130-200°C, more preferably 140-200°C, even more preferably 145-200°C, 180°C, even more preferably 145-180°C, and even more preferably 150-170°C, most preferably at about 160°C. It has been found that such a heating step results in excellent reactions between the components (water-miscible solvent, acrylate, and, if present, polyisocyanate) and their binding to the fabric. In the presence of capped polyisocyanates in the composition, the polyisocyanates also become uncapped at this temperature.

[0029] The optimal heating temperature may also depend on the fabric being treated. In the case of, for example, ultra-high molecular weight polyethylene, the heating temperature is preferably kept below 140°C, particularly around 130°C, because above this temperature, the material may deform. For other fabrics that are more heat-resistant, as mentioned above, the drying temperature is preferably higher, most preferably around 160°C. The heating step can be performed by exposing the treated fabric to a stream of hot air, by residing in a heated chamber, or, for example, by ironing. A skilled technician will know the appropriate temperature selection. The heating step is preferably performed for 30 seconds to 10 minutes, preferably 1-3 minutes.

[0030] Preferably, the fabric treated in step i) is dried before proceeding to the heating step ii). This pre-drying step becomes particularly important in the presence of polyisocyanates, as the crosslinking reaction is preferably carried out in an anhydrous environment. In the absence of isocyanates in the composition, heating and drying can also be combined. However, drying can generally be carried out at a lower temperature than heating. Heating is preferably as described above, for example, between 120°C and 200°C, or at 145-200°C, while drying is preferably carried out between 100°C and 140°C, preferably below 140°C. Therefore, this pre-drying step can be more energy-efficient. Drying is preferably carried out for about 1-10 minutes, preferably about 1-3 minutes.

[0031] In a particularly attractive embodiment, the composition is free of silicone and / or melamine compounds, and preferably also free of fluorine for its sole function of waterproofing. This means that no compounds having fluorine groups in their molecular backbone are present in the composition.

[0032] However, in order to provide a stable and abrasion-resistant coating that is not only waterproof but also oil-resistant, the compositions of the present invention, in attractive embodiments, comprise fluorinated C2-C containing terminal acryloyl groups. 20Alkyl compounds, such as those described in JP2020153057, and those known in the art, such as the Unidyne TG series (Daikin, Japan). By including such a fluorinated acrylate in the composition, the fluorinated acrylate will readily undergo transesterification with a water-miscible solvent as a non-fluorinated acrylate of Formula 1 as described above, and thus will generate a fluorinated hydrocarbon moiety bonded to the fabric fibers by hydrogen bridging and be able to participate in crosslinking with polyisocyanates (if present).

[0033] By providing this fluorinated acrylate, not only water resistance but also oil resistance is achieved. What is particularly attractive is that the fluorinated alkyl compound is defined as a non-fluorinated acrylate of formula 1, wherein for the fluorinated compound, A... 2 Some are C6-C 20 Alkyl groups, from 1 to 6 carbon atoms, are completely substituted with fluorine. The term "completely substituted with fluorine" means that all the H atoms of the corresponding carbon atom have been replaced by fluorine atoms. When completely substituted, the saturated terminal carbon atom will have three fluorine atoms, and the saturated inner carbon (i.e., side-bonded to two adjacent carbon atoms via single bonds) will have two fluorine atoms. This means that fluorine groups can be dispersed throughout the entire alkyl backbone. Such compounds are known, for example, by WO2016 / 096128. Intriguingly, the A2 of fluorinated compounds is a C6 alkyl group, where all 6 carbon atoms are completely substituted with fluorine.

[0034] Because the surface tension of the -CF2- group is 18 mN / m 2 The terminal -CF2 and -CF3 groups are 15 mN / m 2 and 6mN / m 2 Preferably, branched fluorinated alkyl compounds have terminal -CF2 and -CF3 groups, especially -CF3 groups.

[0035] The composition preferably comprises equal amounts of non-fluorinated and fluorinated acrylates, expressed as w / w%. The composition preferably comprises 0.2-20 w / w% acrylates, more preferably 0.5-10 w / w%, and even more preferably 1-6 w / w% fluorinated C2-C. 20 Alkyl compounds. In the presence of fluorinated acrylates, the weight ratio of isocyanate (if present) to acrylic acid is determined by the sum of the fluorinated acrylates and the non-fluorinated acrylates present in the composition.

[0036] The method of the present invention can also be applied to fabric fibers before assembling them into fabrics or textiles, rather than treating the fabrics or textiles. When fabrics or textiles are produced from such treated fibers, similar water resistance is obtained.

[0037] The fibers and / or fabrics are preferably selected from polyester, polyamide, acrylate, ultra-high molecular weight polyethylene (e.g., Dyneema, DSM, Netherlands), cotton, or aramid, or mixtures of two or more thereof. The protective coating has been found to adhere stably and firmly to these types of fabrics. Therefore, the fabrics preferably comprise polyester and / or polyamide, more preferably polyester.

[0038] The treatment in step i) is preferably selected from immersing the fabric in the composition or spraying the composition onto the fabric. Immersion refers to immersing the fabric in the composition. Immersion is preferred, but spraying is a very attractive household appliance where the fabric can be sprayed with an aerosol comprising the composition and then heat-treated by ironing. In industrial settings, the treated fabric is preferably subsequently immersed and rolled to remove excess liquid composition.

[0039] In another aspect, the present invention relates to compositions for imparting durable water resistance to woven or nonwoven fabrics as described above.

[0040] In another respect, the present invention relates to fibers, woven or nonwoven fabrics treated with the aforementioned compositions, particularly the compositions described herein. Attached Figure Description

[0041] Now we will use examples and Figure 1 To further illustrate the invention, a possible industrial setup of the method of the invention is shown.

[0042] The arrows indicate the conveying direction of the fabric 1 guided by the guide roller 2. The process is continuous, for example, without interruption. The fabric 1 is immersed in a bath 3 comprising the composition 4 of the present invention. After exiting the bath 3, the fabric 4 passes through two dip rollers 5, squeezing out excess liquid composition from the fabric. It is dried with hot air in a drying chamber 6, for example, at 130°C, and finally enters a heating chamber 7 at a temperature of, for example, 160°C. Detailed Implementation

[0043] Waterproof

[0044] PES 1 fabric 135 gr / m 2 PES 2 fabric 190 gr / m 2 The sample from (MB Sportswear, Eindhoven Netherlands) was washed 100 times according to the method of Iso 6330 3G or 4H.

[0045] After washing, the water resistance was measured using the spray method according to ISO 4920 (version 2012-12).

[0046] Commercial washing cycle:

[0047] Water resistance was measured using the Iso 4920 spray method after 120 washes with the Express 2.0 program, based on the method used with the Miele Twindos (Germany) commercial washing machine. The detergent color, Reus Super Stain Repellent, is also specified (Henkel, Germany). Detergent program specifications and concentrations are given in Tables 1 and 2, respectively.

[0048] Table 1: Washing Procedure

[0049]

[0050] Table 2: Detergent Composition

[0051]

[0052] Oil resistance

[0053] Oil resistance was determined according to AATCC Method 118-1997 after washing the sample 100 times as described above.

[0054] Sample preparation

[0055] Cut a 15×15 cm sample of fabric from the roll and immerse the fabric in the coating emulsion for 1 minute. Weigh the uncoated fabric in pairs. After immersion, place the coated sample on the rubber sleeve of the manual coating unit (RK Print) for the padding process. Using a smooth roller weighing 10 kg, extrude excess emulsion by rolling the roller twice over the fabric.

[0056] The samples were dried in a forced-ventilation oven at 130°C for 3 minutes; then cured at 160°C for 1 minute. After curing, the samples were weighed again to make a pair.

[0057] Table 3 lists possible compositions for Examples 1-8. Experiments were conducted using the compositions given in Table 4.

[0058] In Examples 1, 3, and 5-10, polyester woven fabrics with PES 135 gr / m were used. 2 ('pique') (MBSportswear, Eindhoven Netherlands), while in Examples 2 and 4, 195 gr / m 2 'smooth' (MB Sportswear, Eindhoven Netherlands).

[0059] It was observed that all samples retained their water resistance after washing cycles and drying in a rotary dryer (AEG Lavatherm Protex plus, AEG, Germany, program set to 'super dry cotton'). The ISO 5 rating of all samples was measured before the first wash and after 100 or 120 washes. A rating of 5 indicates that no adhesion or wetting of the upper surface was observed.

[0060] The same applies to Examples 1 and 3 when spraying is used instead of impregnation and tumbling is used instead of padding in a rotary dryer as described above. Heating was performed by ironing Example 1 at 150°C (level **) and Example 2 at 200°C (level ***) according to the fabric manufacturer's ironing prescription. Similarly, for these samples, the ISO 5 grade of all samples was measured before the first wash and after 100 or 120 washes.

[0061] According to AATCC118 measurements, the oil resistance of Examples 3, 4, 8-10 after 100-120 washes followed by the above-mentioned drum drying was grade 5-6.

[0062] Table 3

[0063]

[0064] Table 4

[0065]

[0066] However, it was observed that, under dry conditions on the production line (i.e., fabrics dried without heating), coatings already cross-linked with polyisocyanates maintained stable bonding compared to those after drum drying, while coatings without isocyanate (NCO) cross-linking tended to detach from the fabric after 10–12 wash cycles (see Table 5). A weight ratio of acrylate to polyisocyanate of 30 or higher was observed to provide the best adhesion.

[0067] Table 5

[0068]

Claims

1. A composition for imparting durable water resistance to woven or nonwoven fabrics, said composition comprising - An aqueous solvent comprising at least 80 w / w% water and 20 w / w% or less water-soluble or water-miscible organic molecules comprising at least two functional OH groups. - 0.1-40 w / w% of acrylates having Formula 1: ， Where A 1 It is H or CH3, and A 2 C1-C, optionally having an alicyclic or aromatic ring. 30 Straight-chain or branched, saturated or unsaturated hydrocarbons, wherein the acrylate is dissolved, emulsified or dispersed in an aqueous solvent, and - A polyisocyanate having at least 3 crosslinkable isocyanate groups.

2. The composition according to claim 1, wherein the water-soluble or water-miscible organic molecule is selected from the group comprising: ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol dimethyl ether, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol, tripropylene glycol monomethyl ether, polypropylene glycol, and hexanediol.

3. The composition according to claim 1 or 2, wherein the water-soluble or water-miscible organic molecule comprises tripropylene glycol.

4. The composition according to claim 1 or 2, wherein the polyisocyanate is a water-based closed polyisocyanate.

5. The composition according to claim 1 or 2, wherein the acrylate A 2 It has 12-24 carbon atoms.

6. The composition according to claim 1 or 2, wherein the acrylate A 2 It is an alkyl group.

7. The composition according to claim 1 or 2, wherein the aqueous solvent comprises 90-99.9 w / w% water and 0.1-10 w / w% water-soluble or water-miscible organic molecules.

8. The composition according to claim 1 or 2, wherein the composition comprises 0.2-20 w / w% acrylate.

9. The composition according to claim 1 or 2, wherein the weight ratio of acrylate to isocyanate is 100:5-100.

10. The composition according to claim 1 or 2, wherein the composition is free of melamine compounds.

11. The composition according to claim 1 or 2, wherein the composition further comprises fluorinated C2-C 20 Alkyl compounds, the fluorinated C2-C 20 Alkyl compounds include terminal acryloyl groups.

12. A method for imparting durable water resistance to woven or nonwoven fabrics, comprising the following steps: i) Treat the fabric with the composition according to any one of the preceding claims. ii) Heat the treated fabric to 120-200°C.

13. The method of claim 12, wherein the fabric treated in step i) is dried before step ii).

14. The method according to claim 13, wherein the fabric is dried at 100-140°C.

15. The method according to any one of claims 12-14, wherein in step ii), the heating is performed for 30 seconds to 10 minutes.

16. The method according to any one of claims 12-14, wherein the treatment in step i) is selected from immersing the fabric in the composition or spraying the composition onto the fabric.

17. A woven or nonwoven fabric treated with the composition of any one of claims 1-11.

18. The woven or nonwoven fabric of claim 17, wherein the fabric is selected from polyester, polyamide, acrylate, ultra-high molecular weight polyethylene, cotton, or a mixture of two or more thereof.

19. The woven or nonwoven fabric according to claim 17, wherein the fabric is an aromatic polyamide.

20. The woven or nonwoven fabric of claim 18, wherein the fabric comprises polyester and / or polyamide.

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