WO2012074419A2

WO2012074419A2 - Process of manufacturing textile barrier materials

Info

Publication number: WO2012074419A2
Application number: PCT/PL2011/000120
Authority: WO
Inventors: Jadwiga SÓJKA-LEDAKOWICZ; Joanna Olczyk; Anetta Walawska; Teofil Jesionowski; Katarzyna SIWIŃSKA-STEFAŃSKA; Agnieszka Przbylska
Original assignee: Instytut Włókiennictwa; Politechnika Poznańska
Priority date: 2010-11-29
Filing date: 2011-11-28
Publication date: 2012-06-07
Also published as: BR112013012019B1; PL219301B1; GB201307313D0; GB2500125A; BR112013012019A2; WO2012074419A3; PL393076A1; GB2500125B; WO2012074419A4

Abstract

The subject of the invention is a process of manufacturing textile materials from polyester fibers by the sulfate and/or emulsion precipitation method, which constitutes barrier materials against UV radiation and microorganisms, using a textile medium modified with alkoxysilanes, titanium dioxide of the anatase type or the Ti0₂-Si0₂ oxide composite.

Description

Process of manufacturing textile barrier materials

The present invention relates to a process of manufacturing textile barrier materials from polyester fibers or their blends containing other fibers by sulfate and/or emulsion precipitation method as opposed to well-known hydrolysis and condensation of organic precursors (the so-called sol-gel method). These materials demonstrate an exceptional resistance to UV radiation and microorganisms as well as photocatalytic properties thanks to introducing into the structure of the textile material the anatase type of titanium dioxide or its oxygen composite Ti0₂-Si0₂ the size of nano- and micrometric particles.

The barrier properties of the textiles against UV radiation may result from the dense textile texture, as described in the patent EP644820B 1. They can also be effectively improved by, among other things, the use of UV absorbers, which are colorless substances that absorb radiation in the wavelength range of 290-400 nm. Depending on the mechanism of action, the UV absorbers can be divided into two groups:

1. Inorganic absorbers, or so-called physical blockers, which reflect and scatter UV radiation. The most commonly used blockers are zinc oxide (ZnO) and titanium dioxide (Ti0₂).

2. Organic so-called chemical blockers, which contain appropriately placed hydrogen bonds. In general, these are aromatic compounds. Thanks to the specific structure, having absorbed high energy radiation (in the wavelength of 250 - 400 nm), the absorber particles pass into the state of induction, and then quickly return to the ground state emitting a low- energy radiation - harmless heat. In terms of their application properties, chemical absorbers are similar to the dyes used in the individual fibers. Therefore, they can be used in one bath of dye or, after dyeing, in the additional application process.

Nowadays, physical blockers are used much more frequently than chemical UV absorbers. They are non-toxic, more stable in relation to chemical absorbers, they provide the protective effect for a significantly longer time, and are resistant to high temperatures. In contrast to the dyes, zinc oxide and titanium dioxide have no affinity to the fibers, and thus they cannot be applied on textiles by using typical dye exhaustion techniques. The ZnO and Ti0₂ microparticles can be added to the spinning bath in the process of producing chemical fibers or applied on fibers like pigments and bound with the protected fiber by means of binding agents.

Nano- Ti0₂ with highly developed surface of contact has the ability to block UV radiation and possesses self-cleaning (photocatalytic) properties. For this reason, it is readily applied to textiles. Due to its high capacity for UV absorption, as well as reflection and scattering of UV radiation, titanium dioxide is used as a physical blocker of UV radiation, increasing the barrier capacity of the textiles it modifies.

The use of Ti0₂, ZnO, A1₂0₃, inter alia, is described in the patent application WO9842909A1.

In the Japanese patent application No. JP 04-179402 (A), the required resistance of polyester fibers to UV radiation was obtained with 1% content of titanium dioxide particles with a diameter of 0.03 microns in the anatase and rutile forms, with a ratio of weight of both forms varieties ranging between 8/2 and 5/5.

A film with antibacterial properties is described in the patent application JP

2003301055 (A).

The patent application JP 2006321087 (A) describes the barrier material based on polyester containing metal oxides such as silicon, titanium, tin, zinc, aluminum, indium.

The anatase type titanium dioxide for modification of polyester textile material is also described in the following JP patent applications: 08-276397, 08-281715, 07-206059, 06- 142167, 01-115764, 01-014066.

There are numerous ways to utilize the photocatalytic properties of titanium dioxide. It meets all the necessary requirements for photocatalyzers due to being easily activated by the UV radiation present in sunlight and in the light emitted by fluorescent tubes, and also due to its photostability and nontoxicity.

One functional material with special useful properties is the Ti0₂-Si0₂ oxide composite. In this composite, the degree of dispersion of titanium dioxide is much greater, and its activity is higher. This also contributes to the transformation from anatase to rutile form, which prevents the growth of titanium dioxide particles during thermal treatment. Additionally, silica increases the specific surface area of titanium dioxide and contributes to the formation of≡ Ti-O-Si≡ bonds. All of this increases photocatalytic activity of the Ti0₂- Si0₂ composite [Ren S., Zhao X., Zhao L., Yuan M., Yu Y., Guo Y., Wang Z., Journal of Solid State Chemistry. 2009, 182, 312, Ennaoui A., Sankapal B.R., Skryshevsky V., Lux- Steiner M.Ch., Solar Energy Materials and Solar Cells 2006, 90, 1533, Xu G., Zheng Z., Wu Y., Feng N., Ceramics International 2009, 35, 1]. Silica-coated titanium dioxide shows a higher thermal and mechanical stability, at the same time a reduced tendency for agglomeration of the particles and an increase the surface activity of the final product are observed.

The U.S. patents (U.S.Patent 4,176,089/1979, 4,410,501/1983, 4,547,557/1985, 5, 162,283/1992 and US 7,790,138 B2/2010) describe various methods for preparing the Ti0₂- Si0₂ composite.

The Ti0₂-Si0₂ mixture obtained by the sol-gel method, applied on a cotton textile product, gives it very good photocatalytic properties [Yuranova T., Mosteo R., Bandara J., Laub D., Kiwi J.: Self-cleaning cotton textiles surfaces modified by photoactive Si0₂ Ti0₂ coating, Journal of Molecular Catalysis A: Chemical: 244 (2006) 160-167].

Polyester textile products modified with the Si0₂-Ti0₂ composite obtained by the sol- gel method from precursors of terra (i-propoxy) titanium (titanium tetraisopropoxide - TTIP) and tetraethoxysilane (tetraetyxysilane - TEOS), also show good photocatalytic properties, which is expressed by a high degree of degradation (up to 96% ) of gaseous formaldehyde [Rusconi F., Colonna GM Bergna L., Cernuto G., G. Zecchi, Masciocch N.: "Nanostructured Si0₂-Ti0₂ photoactive materials for the surface modification of a polyester fabric," Conference proceedings from 22nd IFATCC (International Federation of Textile Chemists and Colorists) International Congress - Stresa , Italy, 5-7 May 2010].

The nature of the invention is the method for obtaining textile barrier material against UV radiation and microbes, while using titanium dioxide particles of the anatase type which are micronized by means of alkoxysilanes or its Ti0₂-Si0₂ oxide composite introduced into the structure of textile material. The process is performed in two stages.

The first stage consists in proper preparation of the textile material in order to increase its adhesive properties. The surface of the polyester fibers is modified by low temperature plasma treatment (non-equilibrium) in the atmosphere of various gases, preferably carbon dioxide or argon. Another way to modify the surface is a controlled treatment of the textile product in a solution of sodium hydroxide at a temperature above 90° C.

In the second stage, micronized particles of titanium dioxide of the anatase type or its oxide composites are introduced into the structure of the textile material in the amount that is not less than 0.5 wt%. and not more than 10% by weight. Polyester fiber products are padded with aqueous dispersion containing micronized particles of functionalized Ti0_2, a wetting agent, and a thickening agent. The dispersion is subjected to intense homogenization by means of a homogenizer at the proper time and speed. Once the padding has been completed in a two-roller padding machine, the excess of dispersion is removed from the samples in order to obtain an adequate level of deposition. Then, the samples are dried and heated up in a heat coating machine. It is best to use aqueous dispersion with 1-5 wt.% of the modified Ti0₂ preparation, a wetting agent - polyethylene glycol (PEG) in the amount of 5-15 wt%. and hydroxyethyl cellulose thickener (HEC) - in the amount of 1-5 wt%.

Another way of incorporating Ti0₂ particles into the structure of the textile product is coating. A properly prepared paste on the basis of acrylic resin and containing the modified titanium dioxide of nano- and micrometric size, a thickening agent, and a wetting agent are applied to a textile carrier using a special kit for application of nanostructured film coatings. The film's thickness is controlled by adjusting the feeding slot/gap between the coating blade and the textile material being coated. In the final stage, the product with the applied coating is dried and heated up. It is best to use paste containing 1-3 wt.% of modified Ti0_2, a wetting agent - polyethylene glycol (PEG) in the amount of 5-15 wt.%, styrene-acrylic resin with no more than 20 wt.%, acrylic thickening agent of 3-10 wt.%.

The subject of the invention has been presented in a way which does not limit its scope, in the following examples of use.

Example I.

The process of padding polyester woven fabric.

An anatase sample was placed in a reactor with the capacity of 500 cm³ and sprayed with the 3-Methacryloxypropyltrimethoxysilane solution by means of a special spray system (atomizer). The solution contained a binding silane compound in the amount of 0.5 wt. parts of silane per 100 wt. parts of anatase. The binding silane compound was hydrolyzed in a mixture of methanol and water at the volume ratio of 4: 1. Then, the system was stirred for 1 hour in order to perfectly homogenize the anatase sample with the solution of the modifying compound and the solvent was distilled off. The modified sample was dried at the temperature of 105°C in a stationary dryer for 2 hours. From the sample prepared in this way an aqueous dispersion was made containing 3 wt%. of this sample, a wetting agent - polyethylene glycol in the amount of 10 wt%., and a thickening agent - hydroxyethyl cellulose in the amount of 1 wt%., with which the polyester fabric was padded after having been subjected to alkaline pre- treatment process. The dispersion was subjected to intense homogenization using a homogenizer for the duration of 60 s with the assumed speed of 20000 r / min. After the padding in a two-roller padding machine and removing the excess dispersion, the samples were dried for 3 minutes at the temperature of 100°C in a heating unit and heated up at the same temperature for 10 minutes. The alkaline pre-treatment of polyester fabric was conducted in a laboratory dyeing apparatus at bath ratio 10:1, in a bath composed of sodium hydroxide, 38° BE - 1.8 g/dm3, sodium carbonate - 4.1 g/dm3, sequestering and wetting agent - 1,0 g/dm3. The process was carried out at the temperature of 98°C for the duration of 60 minutes. After treatment, the fabric was rinsed for 10 minutes in a water bath at the temperature of 80 ° C, and then under running water.

Example II

The process of modifying titanium dioxide was carried out in the same way as in

Example I using 1 wt. part of silane per 100 wt. parts of anatase.

Example III

The process of modifying titanium dioxide was carried out in the same way as in Example I using 3 wt. parts of silane per 100 wt. parts of anatase.

Example IV

The process of padding polyester nonwoven fabric.

The modification process was carried out in the same way as in Example I. Vinyltrimethoxysilane was used as a silane. From the sample prepared in this way, an aqueous dispersion was made containing 3 wt% of the sample, a wetting agent - polyethylene glycol in the amount of 10 wt%. and a thickening agent - hydroxyethyl cellulose in the amount of 1 wt%. It was then padded onto the polyester nonwoven fabric which had previously been subjected to plasma pre-treatment. The dispersion was subjected to intense homogenization by means of a homogenizer for the duration of 60 s with the assumed speed of 20 000 r/min. After the padding in a two-roller padding machine and removing the excess dispersion, the samples were dried for 3 minutes at the temperature of 100°C in a heating unit and heated up at the same temperature for 10 minutes. The plasma treatment of the polyester nonwoven fabric was carried out at RF discharge (13.56 MHz frequency). Plasma was generated in argon. The duration of the treatment was 15 s.

Example V.

The process of coating polyester woven fabric.

The process of modifying anatase was carried out in the same way as in Example I. N-2-(aminoethyl)-3-aminopropyltrimethoxysilane was used as silane. From the sample prepared in this way, a coating paste was obtained on the basis of acrylic resin in the amount of 10 wt.% containing 3 wt.% of anatase preparation, a thickening agent of 4.5 wt.%, and a wetting agent (polyethylene glycol) of 10 wt.% with uniform dispersion and viscosity of 68 dPas which was applied to a polyester fabric previously subjected to alkaline pre-treatment process. The process of coating polyester fabric was performed using a special kit for application of nanostructured coatings. The film's thickness was controlled by adjusting the feeding slot/gap between the coating blade and the textile material being coated - 0.05 mm. In the final stage, the samples were dried (heated up) at the temperature of 120°C for the duration of 6 minutes. The alkaline pre-treatment of polyester fabric was conducted in a laboratory dyeing apparatus at 10: 1 bath ratio, in a bath composed of sodium hydroxide, 38° BE - 1.8 g/dm3, sodium carbonate - 4.1 g/dm3, sequestering and wetting agent - 1,0 g/dm3. The process was carried out at the temperature of 98°C for the duration of 60 minutes. After the treatment, the fabric was rinsed for 10 minutes in a water bath at the temperature of 80° C, and then under running water.

Example VI

The process of coating polyester nonwoven fabric.

Before the process of precipitation, a suspension of titanium sulfate was centrifuged for 30 minutes at the speed of 2500 rpm/min, until a clear solution was obtained. In the process of precipitation of oxide Ti0₂-Si0₂ composites two emulsions were prepared. First, the E2 emulsion was formed, which consisted of cyclohexane, titanium sulfate, and nonionic surfactants. The components of this emulsion were homogenized. In the next stage, the El emulsion was prepared consisting of cyclohexane, 20% solution of sodium silicate and hydrophobizing agents. The El emulsion was also homogenized. Then, using a peristaltic pump emulsion El was dosed into the E2 emulsion at the rate of 10 cnrVmin., all the while homogenizing the system. Then, the precipitation reaction system was destabilized at 80 ° C for 30 minutes. The resulting deposit was separated from the post-reaction mixture by means of filtration, and the solvent was distilled off. Drying was carried out in a stationary dryer at the temperature of 105° C for approximately 18 h. The dried Ti0₂-Si0₂ deposit was subjected to calcination in an oven at the temperature of 1000° C for 1 h. From the sample prepared in this way a coating paste was made on the basis of acrylic resin of 10 wt%. containing 3 wt%. Ti0₂-Si0 oxide composite, 4.5 wt.% thickener, and a wetting agent (polyethylene glycol) - 10 wt.% with uniform dispersion, and viscosity of 90 dPas, which was applied to a nonwoven polyester previously subjected to plasma treatment process. The process of coating polyester nonwoven fabric was performed using a special kit for application of nanostructured coatings. The film's thickness was controlled by adjusting the feeding slot/gap between the coating blade and the textile material being coated - 0.05 mm. In the final stage, the samples were dried (heated up) at the temperature of 120°C for the duration of 6 minutes. The plasma treatment of the polyester nonwoven fabric was carried out at RF discharge (13.56 MHz frequency). Plasma was generated in carbon dioxide. The duration of the treatment was 15 s.

The barrier properties of the modified textiles for UV radiation, as measured by the UPF (Ultraviolet Protection Factor) ratio, were determined based on the measurements of the transmittance of UV radiation of fabric by means of the spectrophotometric method.

The photooxidative activity was assessed based on the possibility of removing organic pollutant - formaldehyde, from the air in a closed system in which a sample of a textile product with titanium dioxide was placed - photocatalysing decomposition reactions of simple inorganic compounds.

By using the solution described in this invention, a product is obtained with barrier properties for UV radiation expressed by a reduced value of spectral transmittance in the whole UV range (increasing of absorption) and by the value of the coefficient UPF>50 determined in accordance to the standard EN 13758-1. It is characterized by a very good photooxidative activity (the decomposition efficiency of formaldehyde is 90-98%) and the inhibitory action of microorganisms like Bacillus subtilis, Micrococcus fla s, Pseudomonas aureginosa, Escherichia coli (Table 1).

Table 1. Barrier properties and photooxidative activity of nonwoven polyester containing in its structure anatase modified with alkoxysilanes or the Ti0₂ - Si0₂ oxide composite.

The antimicrobial properties of the modified textile product containing Ti0₂ of the anatase type in its structure were assessed by a screening method according to the standard EN ISO 20645 (agar plate diffusion test), based on the presence and size of the inhibition zone inhibiting the growth of the tested microorganisms around the examined sample and the growth, or lack thereof, in the contact zone of the sample with the culture medium.

The resulting protective effect against UV radiation and the development of microorganisms is stable and maintained even after 10 laundry cycles.

Using the solution described in this invention does not cause significant changes in mechanical parameters of the textile material to which the barrier properties for UV radiation and the development of microorganism, as well as photooxidative properties, were applied.

Claims

Patent claims

1. A process of manufacturing textile barrier materials from polyester fibers or their blends containing other fibers using the anatase form of alkoxysilane-modified titanium dioxide or the oxygen composite Ti0₂-Si0₂ by the sulfate and/or emulsion precipitation method, in which the modified anatase type of titanium dioxide or its Ti0₂-Si0₂ oxide composite is introduced into the structure of a plasma and/or alkaline pre-treated polyester fiber product through coating it with a paste on the basis of acrylic resin or padding it with a water dispersion, while to the textile product anatase particles or the Ti0₂-Si0₂ oxide composite of nano- and micrometric size in the amount not less than 0.5 wt.% and not more than 10 wt.% are introduced.

2. The process according to claim 1 in which the surface of polyester fibers is modified by low-temperature plasma treatment in a gas atmosphere, preferably in the atmosphere of carbon dioxide or argon.

3. The process according to claim 1 in which the surface of polyester fibers is modified by a treatment in a solution of sodium hydroxide at a temperature above 90° C.

4. The process according to claim 1 in which for the coating process a paste is used containing modified anatase or the Ti0₂-Si0₂ oxide composite in an amount of 1-5 wt.%, a wetting agent in an amount of 5-15 wt%., an acrylic thickening agent in an amount of 3-10 wt.% and up to 20 wt.% of styrene-acrylic resin.

5. The process according to claim 1 in which for the padding process a water dispersion is used containing 1-5 wt.% of modified anatase or the Ti0₂-Si0₂ oxide composite, 5-15% of a wetting agent, and 1-5% of a thickening agent.