DAMAGE-RESISTANT GLOVES WITH BREACH-INDICATOR FUNCTION

Abstract

The present invention relates to a multi-layered latex cover, particularly a glove, comprising a main body and a rim. The main body comprises an outer latex layer, an inner latex layer and an intermediate layer comprising particles. The rim essentially consists of the agglutinated outer and inner latex layer. The particles in the intermediate layer are chemically functionalized with a compound comprising hydrophobic groups. Prior to functionalization, the particles are characterized by a mean diameter of 100 m and a surface comprising exposed OH groups. The invention further relates to a method of producing the multi-layered cover, comprising the steps of providing a former and sequentially immersing it in a first coagulator solution, a first latex dispersion, a particle suspension and a second latex dispersion.

Claims

1. A multi-layered cover, particularly a glove for a human hand, comprising a main body and a rim, wherein said main body comprises a. an outer latex layer b. an inner latex layer c. an intermediate layer comprising particles, wherein said particles are characterized by i. a mean diameter of 100 m and ii. a surface comprising exposed OH groups when in a non-functionalized state; and said rim essentially consists of the agglutinated outer and inner latex layer, characterized in that said particles are chemically functionalized with a compound comprising hydrophobic groups.

2. The multi-layered cover according to claim 1, wherein said particles comprise or essentially consist of inorganic particles, in particular particles made from silica, titanium dioxide or zirconium dioxide, more particularly particles made from silica.

3. The multi-layered cover according to any one of the preceding claims, wherein said particles are characterized by a. a mean diameter of 10 m, more particularly a mean diameter of 1 m, even more particularly a mean diameter of 0.1 m, or b. 90% of said particles having a diameter of 10 m, more particularly 90% of said particles having a diameter of 1 m, even more particularly 90% of said particles having a diameter of 0.1 m

4. The multi-layered cover according to any one of the preceding claims, wherein said particles are characterized by a surface comprising exposed OH groups having a density of 2-5 mnm.sup.2, in particular 2.2-2.5 /nm.sup.2.

5. The multi-layered cover according to any one of the preceding claims, wherein said compound comprising hydrophobic groups is a compound comprising a. an unsaturated group, particularly an unsaturated carbon-carbon double bond, more particularly a CHCH.sub.2 moiety, or b. sulfur, particularly wherein said compound comprising hydrophobic groups is selected from 7-octenyltrimethoxysilane, 5-hexenyltrimethoxysilane, 3-mercaptopropyltrimethoxy-silane, 3-(aminopropyl) triethoxysilane, tris(2-methoxyethoxy)(vinyl)silane, allyltrimethoxysilane, 3-(amino propyl)triethoxysilane, hexadecyltrimethoxysilane, vinyltrimethoxysilane, triethoxyvinyl silane, 3-trimethoxysilylpropane-1-thiol, bis[3-(triethoxysilyl)propyl]tetrasulfide, 3-(methacryloxypropyl)trimethoxysilane and 3-N-(3-triethoxysilylpropyl)gluconamide.

6. The multi-layered cover according to any one of the preceding claims, wherein said functionalized particles have an at least partially hydrophobic surface.

7. The multi-layered cover according to any one of the preceding claims, wherein said particles are additionally functionalized with a compound comprising hydrophilic groups, particularly selected from polyethylene glycol, polyglycerol, and N-(3-triethoxysilylpropyl)gluconamide or 3-[methoxy(polyethyleneoxy)propyl]trimethoxy-silane.

8. The multi-layered cover according to any one of the preceding claims, wherein said functionalized particle has an amphiphilic particle surface.

9. The multi-layered cover according to any one of the preceding claims, wherein said particles are functionalized with at least two different compounds.

10. The multi-layered cover according to claim 9, wherein a. a first compound is selected from compounds suitable for yielding a hydrophobic surface, in particular the first compound is a compound comprising an unsaturated group (more particularly a CHCH.sub.2 moiety) or sulfur, more particularly a compound selected from 7-octenyltrimethoxysilane, 5-hexenyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-amino propyl)triethoxysilane, tris(2-methoxyethoxy)(vinyl)silane, allyltrimethoxysilane, 3-(aminopropyl)triethoxysilane, hexadecyltrimethoxysilane, vinyltrimethoxy silane, triethoxyvinylsilane, 3-trimethoxysilylpropane-1-thiol, bis[3-(triethoxy silyl)propyl]tetrasulfide, 3-(methacryloxypropyl)trimethoxysilane and 3-N-(3-triethoxysilylpropyl)gluconamide, and b. a second compound is selected from compounds suitable for yielding a hydrophilic surface, in particular a substance selected from polyethylene glycol, polyglycerol, N-(3-triethoxysilylpropyl)gluconamide and 3-[methoxy(polyethylene oxy)propyl]trimethoxysilane.

11. The multi-layered cover according to any one of the preceding claims, wherein said particles are chemically linked to the inner and/or outer latex layer, particularly to the face of the latex layer facing the intermediate layer.

12. The multi-layered cover according to any one of the preceding claims, wherein said inner and/or outer latex layer is characterized by a contact angle with water of <90, particularly <45, on a face of the latex layer facing the intermediate layer.

13. The multi-layered cover according to any one of the preceding claims, wherein said multi-layered cover is characterized by a thickness of 100 m to 800 m uniformly extending across its entire dimensions.

14. The multi-layered cover according to any one of the preceding claims, wherein said outer layer and said inner latex layer are agglutinated at discrete regions, particularly at regions of 1 mm.sup.2 to 5 cm.sup.2, more particularly regions of 4 mm.sup.2 to 2.5 cm.sup.2, even more particularly regions of 9 mm.sup.2 to 1 cm.sup.2, more particularly approx. 25 mm.sup.2 at each fingertip.

15. The multi-layered cover according to claim 14, wherein said discrete regions form patterns, signs, characters or numbers.

16. The multi-layered latex cover according to any one of the preceding claims, wherein said intermediate layer comprises a plurality of double layers comprising a. particles having a mean diameter of 100 m and a surface comprising exposed OH groups, wherein said particles are chemically functionalized with a compound comprising hydrophobic groups, and b. a latex layer.

17. A multi-layered latex cover according to claim 16, wherein the inner latex layer, or the inner latex layer and adjacent latex layers of the intermediate layer are perforated.

18. A glove comprising or essentially consisting of a multi-layered cover according to any one of claims 1 to 17.

19. A method of producing a multi-layered cover, comprising the steps of: a. providing a former, particularly a former having the shape of a human hand; b. immersing said former in a first coagulator liquid, to an immersion depth d.sub.1, then retracting and drying said former; c. immersing said former in a first latex dispersion to an immersion depth d.sub.2, then retracting and drying said former, yielding a first latex covered former; d. applying chemically functionalized particles to said first latex covered former to an immersion depth d.sub.3; yielding a particle treated former; wherein said particles are in a non-functionalized state characterized by a mean diameter of 100 m and a surface comprising exposed OH groups, particularly at a density of 2-5 mnm.sup.2, more particularly 2.2-2.5 /nm.sup.2, and chemically functionalized with a compound comprising hydrophobic groups; e. immersing said particle treated former in a second latex dispersion to an immersion depth d.sub.4, then retracting and drying said particle treated former; yielding a second latex covered former, wherein d.sub.1d.sub.2>d.sub.3 and d.sub.1d.sub.4>d.sub.3; f. removing the applied layers from said coated former, yielding said multi-layered cover.

20. The method according to claim 19, wherein between step e and f, a step is performed whereby a coating is applied to said second latex covered former, yielding a coated former.

21. The method according to claim 19 or 20, wherein said step d is effected by immersing said first latex covered former in an aqueous suspension comprising chemically functionalized particles at a concentration of between 0.2 and 7 mol/L, particularly approx. 1 mol/L to an immersion depth d.sub.3.

22. The method according to any one of claims 19 to 21, wherein said chemically functionalized particles are applied in step d from an aqueous suspension with a concentration of 0.2 and 7 mol/L, particularly approx. 1 mol/L by adding a latex dispersion (40-80 wt %, particularly 60 wt % solid content) with a volume ratio of suspension to latex dispersion of less than 1:20.

23. The method according to any one of claims 19 to 22, wherein discrete regions are cleaned from said chemically functionalized particles subsequently to step d and previous to step e.

24. The method according to any one of claims 19 to 22, wherein an adhesive cover covering discrete regions is applied to the former subsequently to step c and prior to step d, and peeled off after step d.

25. The method according to claim 23 or 24, wherein said discrete regions are regions of 1 mm.sup.2 to 5 cm.sup.2 to, more particularly regions of 4 mm.sup.2 to 2.5 cm.sup.2, even more particularly regions of 9 mm.sup.2 to 1 cm.sup.2, more particularly approx. 25 mm.sup.2 at each fingertip.

26. The method according to claim 25, wherein said discrete regions form agglutinated patterns, signs, characters or numbers.

27. The method according to any one of claims 19 to 26, wherein said first and second latex dispersions and the chemically functionalized particles comprise a vulcanization system, and wherein following retraction of said particle treated former from said second latex dispersion in step e, a vulcanization step is carried out at a temperature between 100 C. and 200 C., in particular at approx. 140 C.

28. The method according to any one of claims 19 to 27, wherein steps d and e are repeated several times, yielding a multi-layered latex cover having more than two latex layers.

29. The method according to any one of claims 19 to 28, wherein said particles are silica particles.

30. The method according to any one of claims 19 to 29, wherein said particles are functionalized by covalent attachment to the surface of a compound selected from 7-octenyltrimethoxysilane, 5-hexenyltrimethoxysilane, 3-mercaptopropyltrimethoxy-silane, 3-amino propyl)triethoxysilane, tris(2-methoxyethoxy)(vinyl)silane, allyl-trimethoxysilane, 3-(aminopropyl)triethoxysilane, hexadecyltrimethoxysilane, vinyltrimethoxy silane, triethoxyvinylsilane, 3-trimethoxysilylpropane-1-thiol, bis[3-(triethoxy silyl)propyl]tetrasulfide, 3-(methacryloxypropyl)trimethoxysilane and 3-N-(3-triethoxysilylpropyl)gluconamide.

31. The method according to claim 30, wherein said particles are additionally functionalized by covalent attachment of a second compound selected from polyethylene glycol, polyglycerol, N-(3-triethoxysilylpropyl)gluconamide and 3-[methoxy(polyethylene oxy)propyl]trimethoxysilane

Description

BRIEF DESCRIPTION OF THE FIGURES

[0141] FIG. 1 illustrates the immersion depth during the dipping process. 1: former, 2: first coagulator liquid, 3: first latex dispersion/first latex layer, 4: particle suspension, 5: second latex dispersion/second latex layer, d.sub.1-d.sub.4: immersion depth.

[0142] FIG. 2 shows a double-layered latex glove on a former at the end of the dipping process. The different layers of the glove are indicated in the left-hand circles. 1: former, 2: coagulator layer, 3: first latex layer, 4: particle layer, 5: second latex layer. The upper circle shows a region of the glove in which first and second latex layers are agglutinated. The lower circle shows a region of the glove in which first and second latex layers are separated.

[0143] FIG. 3 shows silica particles that are positioned between inner and outer latex layer. The particles are anchored in the inner latex layer.

[0144] FIG. 4 shows a double layered finger cot. Arrows indicate the agglutinated and separated regions (a) and the cross-section (outer and inner layers, b).

[0145] FIG. 5 shows a latex layer, which was dip-coated with functionalized silica particles and washed with a water-ethanol mixture. The particles adhere to the latex layer. This status is an intermediate step for the production of a double-layered system with particles chemically linked to one of the layers. Afterwards, this molding blank is further processed by dipping into the second latex dispersion, drying and vulcanization.

[0146] FIG. 6 shows a double layered finger cot with an agglutinated fingertip.

[0147] FIG. 7 shows the diagrams referred to in Example 1

[0148] FIG. 8 shows infrared spectra measured using Diffuse Reflectance Infrared Fourier Transform Spectroscopy (in KBr pellets) of i) silica particles functionalized with triethoxyvinylsilane (VTES) and PEG2000 and ii) silica particles with VTES only. Bands of VTES (grey) and PEG2000 (white) are marked in the IR spectra.

[0149] FIG. 9 shows dip-coated multi-layered covers comprising two natural rubber layers and an intermediate layer of functionalized silica particles. [0150] a) Time-dependent influx of a water droplet (2 s, 10 s, 20 s, 30 s, 40 s, 50 s, 60 s, 120 s, 180 s after perforation) shown for covers containing silica particles functionalized with VTES +PEG2000. [0151] b) Perforation indicator effectiveness (PIE, effective area of changing color over time) in dependence of surface functionalization of silica particles (triethoxyvinylsilane (VTES) +PEG2000, VTES, 3-(aminopropyl)triethoxysilane (APTES)). [0152] c) Light-microscopy images of the cross-section of the covers showing the outer layer (1), the inner layer (2) and the intermediate layer of silica particles functionalized with VTES +PEG2000, VTES and APTES.

[0153] FIG. 10 exemplarily shows water droplets on natural rubber surfaces covered with functionalized silica particles and the resulting contact angle in dependence of surface functionalization of silica particles (triethoxyvinylsilane (VTES) +PEG2000, VTES, 3-(aminopropyl)triethoxysilane (APTES).

EXAMPLES

Example 1 A

Optimization of Calcium Nitrate Concentration (Diagram FIG. 7 A)

[0154] The effect of the calcium nitrate concentration [% (v/v), calculated on the basis of Ca(NO.sub.3).sub.2*4H.sub.2O] on the thickness of a single latex layer was analysed. Latex: 60% (v/v); calcium carbonate: 10% (v/v).

Example 1 B

Optimization of Calcium Carbonate Concentration (Diagram FIG. 7 B)

[0155] The effect of the calcium carbonate concentration [% (v/v)] on the thickness of a single latex layer was analysed. Latex: 60% (v/v); calcium nitrate: 2.3% (v/v).

Example 1 C

Optimization of Latex Dispersion (Diagram FIG. 7 C)

[0156] The effect of the latex concentration [% (v/v)] on the thickness of a single latex layer was analysed. Calcium carbonate: 10% (v/v); calcium nitrate: 2.3% (v/v).

Standard Protocol for Glove Production According to the Invention

[0157] 1) Coagulator with release agent solution, exemplarily: [0158] 1.5 I water [0159] 110 g calcium nitrate [0160] 600 g calcium carbonate (CaCO.sub.3) [0161] 2) Concentration Latex 1: 30% [0162] 3) Silica particle suspension [0163] 4) Concentration Latex 2: 60%

Particle Functionalization with Silanes

[0164] (exemplarily described for 1 g of particles and tris(2-methoxyethoxy)(vinyl)silane as silane) [0165] 1. Silica particles are suspended in 30 ml of Ethanol and 30 ml of NaOH solution (1 mol l.sup.1) and treated by ultrasound. [0166] 2. 10 ml of Ethanol, 10 ml of NaOH solution (1 mol l.sup.1) and 5 ml of silane are added. [0167] 3. The solution is stirred for 2 h at room temperature. [0168] 4. The particles were centrifuged and washed for two times with ethanol. [0169] 5. The suspension was dried at 30 C. for 12 hours. [0170] 6. The particles were mechanically threated to get a powder. [0171] 7. The particles are suspended in a mixture of 70% water and 30% alcohol.

Particle Functionalization with Either PEG or Silanes

[0172] SiO.sub.2 particles were suspended in water and mixed with the appropriate amount of silane or PEG. The pH was adjusted to 9-10 and the suspension was stirred at 75 C. for about 2-4 h. The dispersion was then dried at 75 C. for several hours to remove the solvent. The powder was then washed twice each with H.sub.2O and EtOH and centrifuged. The resulting particles were dried at 75 C. for several hours to obtain the final product.

Particle Functionalization with PEG and Silanes

[0173] As PEG, PEG200, PEG2000, PEG10000, PEG20000 and more were used. As silanes, one of the following were employed: tris(2-methoxyethoxy)(vinyl)silane, allyltrimethoxysilane, 3-(aminopropyl)triethoxysilane, hexadecyltrimethoxysilane, vinyltrimethoxysilane, triethoxyvinyl silane, 3-trimethoxysilylpropane-1-thiol, bis[3-(triethoxysilyl)propyl]tetrasulfide, 3-(methacryl oxypropyl)trimethoxysilane, 3-[methoxy(polyethyleneoxy)propyl]trimethoxysilane, N-(3-triethoxysilylpropyl)gluconamide.

[0174] The reaction was carried out as follows:

[0175] A corresponding amount of silane (10 mol % or above) was added to a suspension of silica particles in H.sub.2O/EtOH (1:1 v/v). After adjusting the pH to 9-10 (NaOH or NH.sub.4OH) the suspension was stirred for 5 min. Afterwards PEG (between 10 and 70 mol %) was added and the reaction mixture was stirred until PEG was dissolved. The mixture was then stirred at 75 C. for 8 h. After removing the solvent, the particles were washed with H.sub.2O and EtOH several times to remove unreacted compounds. The particles were then dried at 70 C. for 24 h to obtain the final product.

Measuring Instructions for Perforation Indicator Effectiveness (PIE)

[0176] 1. Place double-layered cover on an coloured former [0177] 2. Puncture with needle [0178] 3. Place water drop on top of perforation (excess water) [0179] 4. Trigger water inflow by application of slight mechanical stress parallel to the layers (strain the perforation) [0180] 5. Take pictures with a defined length scale for calibration and after a defined period of time (2 s, 10 s, 20 s, 30 s, 40 s, 50 s, 60 s, 120 s, 180 s after perforations). [0181] 6. Quantify the PIE by measuring the affected area with image-processing, e.g. by the help of the software ImageJ (Schneider, C. A.; Rasband, W. S.; Eliceiri, K. W. (2012), Nature methods 9(7):671-675). Make sure to only consider water in between the layers, not in between latex and former.

Contact Angle Measurements

[0182] Contact angles were determined using a Kyowa Dropmeter (DMs-401) equipped with a 32 G needle from stainless steel. Drops of 2.0 l of purified water were placed on horizontally aligned sample surfaces (sessile drop technique). A picture was taken and evaluated 10 s after surface deposition of the drop. Data acquisition and analysis was performed using the half-angle method in the interFAce Measurement and Analysis Software FAMAS.

Material

[0183] Neotex FA: natural latex, full ammonia, 60% Polyisopren with natural associated material [0184] ProChemie-Latex: 60%, FA, Polyisopren with natural associated material [0185] Vulcanizer: Suprotex L 4204-2, Weserland.eu [0186] Calcium carbonate (CaCO.sub.3), CAS-No. 471-34-1, S3-Chemicals [0187] Calcium nitrate tetrahydrate (Ca(NO.sub.3).sub.2*4H.sub.2O), CAS-No. 13477-34-4, S3-Chemicals, 98% [0188] Talcum powder: diacleanshop, CAS-No. 14807-96-6, EG-No. 238-877-9 [0189] Silica particles: Kremer Pigmente, spheric, <50 m [0190] Silica particles, fumed, CAS 112945-52-5, Sigma Aldrich 0.007 m [0191] Silica particles, fumed, CAS 112945-52-5, Sigma Aldrich 0.2-0.3 m [0192] Silica particles: Fumed silica OX50 (Aerosil), CAS 112 945-52-5, (ex 7631-86-9) [0193] Tris(2-methoxyethoxy)(vinyl)silane, CAS 1067-53-4, Sigma Aldrich [0194] Allyltrimethoxysilane, CAS 2551-83-9, ABCR [0195] 3-(Aminopropyl)triethoxysilane, CAS 919-30-2, Sigma Aldrich [0196] Hexadecyltrimethoxysilane, CAS 16415-12-06, Sigma Aldrich [0197] Vinyltrimethoxysilane, CAS 2768-02-7, Sigma Aldrich [0198] Triethoxyvinylsilane, CAS 78-08-0, Merck [0199] 3-Trimethoxysilylpropane-1-thiol, CAS 4420-74-0, Evonik [0200] Bis[3-(triethoxysilyl)propyl]tetrasulfide, CAS 40372-72-3, ABCR [0201] 3-(Methacryloxypropyl)trimethoxysilane, CAS 2530-85-0, ABCR [0202] 3-[Methoxy(polyethyleneoxy)propyl]trimethoxysilane, CAS 65994-07-2, ABCR [0203] N-(3-triethoxysilylpropyl)gluconamide, CAS 104275-58-3, ABCR [0204] Heliogen Blau: Kremer Pigmente, blue pigment [0205] Uranin: Kremer Pigmente, yellow pigment [0206] PEG 200, PEG 2000, PEG 10000, PEG 20000, CAS 25322-68-3, Carl Roth