Thermal stabilizer material, method of obtaining and uses thereof

Abstract

The present disclosure relates to the use of eggshell particles as a polymer thermal stabilizer, preferably as a poly(vinyl chloride) (PVC) thermal stabilizer; also to a flexible material comprising a multi-layered PVC-based material, method of obtaining and uses thereof.

An aspect of the present disclosure relates to a material comprising a poly(vinyl chloride), PVC, layer comprising eggshell particles, wherein the eggshell particle size is up to 200 μm, an intermediate layer or a plurality of intermediate layers; a support layer selected from the following list: fabric, knitted fabric, nonwoven, foam, or mixtures thereof; wherein the layers are bounded. Preferably a material solution free of azodicarbonamide, for automotive Interiors—Eco-friendlier, preferably sustainable artificial leather for automotive upholsteries.

Claims

1. A material comprising; a poly(vinyl chloride), PVC, layer comprising eggshell particles, wherein the eggshell particle size ranges from 0.1-200 μm, an intermediate layer or a plurality of intermediate layers; a support layer selected from the group consisting of: fabric, knitted fabric, nonwoven, foam, and mixtures thereof; wherein the layers are bounded; wherein the amount of eggshell particles of the PVC layer is up to 20% (wt .sub.eggshell/wt.sub.PVC layer), wherein the reduction of VOC/FOG emission is from 5 to 25%; and wherein the flexible material is resistant to impact and flexing according to standard VDA 230-225:2014.

2. The material of claim 1, wherein the plurality of intermediate layers is a foam layer and/or an adhesive layer.

3. The material of claim 1, wherein the amount of eggshell particles of the PVC layer is up to 10% (wt .sub.eggshell/wt .sub.PVC layer).

4. The material of claim 1, wherein the amount of eggshell particles of the PVC layer is from 0.2-5% (wt .sub.eggshell/wt .sub.PVC layer).

5. The material of claim 1, wherein the eggshell particle size is 1 to 50 μm.

6. The material of claim 1, wherein the heat aging is graded as 4-5.

7. The material of claim 1, wherein the eggshell particles d50 is from 1.0 to 20 μm.

8. The material of claim 2, wherein the foam layer further comprises eggshell particles; and/or the adhesive layer further comprises eggshell particles.

9. The material of claim 8, wherein the amount of eggshell particles of the foam layer/adhesive layer is from 0.2-5 (wt .sub.eggshell/wt .sub.foam layer).

10. The material of claim 8, wherein the poly(vinyl chloride) layer, and/or the foam layer and/or adhesive layer comprises polymeric microspheres.

11. The material of claim 10, wherein the polymeric microspheres are an expandable material, preferably containing a hydrocarbon with a low boiling point and a thermoplastic shell.

12. The material of claim 11, wherein the microsphere particle diameter is from 1-50 μm.

13. The material of claim 1, wherein any layer comprises sublayers.

14. (canceled)

15. An article comprising the material of claim 1, wherein the article is upholstery or a seat or door panel or automotive interior trim.

16. A method for obtaining the material of claim 1, comprising the following steps: obtaining the eggshell particles comprising a size up to 200 μm; obtaining a metal soap of one or more calcium and zinc salts, wherein the salts are selected from the group consisting of: Zn(Ac).sub.2, ZnSO.sub.4, Ca(Ac).sub.2, Ca(NO.sub.3).sub.2, Ca(OH).sub.2, Ca(NO.sub.3).sub.2/Ca(OH).sub.2, a Ca(Ac).sub.2/Ca(OH).sub.2 mixture, and mixtures thereof; optionally mixing the eggshell particles and the metal soap, wherein the metal soup comprises epoxidized oils; adding the mixture or the eggshell particles to a PVC paste to obtain a stabilized PVC layer; and binding the obtained PVC layer to an intermediate layer or the plurality of intermediate layers and to the support layer.

17. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The following figures provide preferred embodiments for illustrating the description and should not be seen as limiting the scope of invention.

[0050] FIG. 1— Particle size distribution (PSD) of an eggshell sample.

[0051] FIG. 2— SEM Images.

[0052] FIG. 3— Effect of milling of the paste (eggshell+plasticizer) in the PVC layer.

[0053] FIG. 4— Illustrates an embodiment of the reference flexible material.

[0054] FIG. 5— Illustrates an embodiment of a version 1 of the flexible material of the present disclosure.

[0055] FIG. 6— Illustrates an embodiment of a version 2 of the flexible material of the present disclosure.

[0056] FIG. 7—Illustrates an embodiment of a version 3 of the flexible material of the present disclosure.

[0057] FIG. 8—Illustrates an embodiment of the material of the present disclosure.

[0058] FIG. 9— Illustrates an embodiment of the material of the present disclosure.

[0059] FIG. 10— Illustrates an embodiment of the material of the present disclosure.

DETAILED DESCRIPTION

[0060] The present disclosure relates to the use of eggshell particles as a polymer thermal stabilizer, preferably as a poly(vinyl chloride) (PVC) thermal stabilizer; also to a flexible material comprising a multi-layered PVC-based material, method of obtaining and uses thereof.

[0061] Stricter environmental, clean air and waste management legislation drives the automotive industry market towards “green” chemistry and lower-VOC emissions processes/materials. Automotive composite materials must fulfil rigorous technical specifications and high performance/quality standards, in terms of long-term functionality, human/environment safety, comfort, as well as low rates of volatile organic compounds (VOC) emitted from car interior components and using cost-competitive raw materials. This disclosure uses a by-product of egg industry as an additive to improve the thermal stability and the thermal aging behaviour of flexible PVC-based car interior components, as well as to reduce VOC emissions from these materials, when compared with currently available commercial equivalents.

[0062] The degradation of PVC can occur when it is exposed to radiation and/or high temperature due to dehydrochlorination, auto-oxidation, mechanical-chemical chain scission, crosslinking and condensation reactions that may cause the release of hydrogen chloride (HCl), accompanied by the formation of polyenic sequences and cross-links in PVC chains, resulting in a rapid degradation process, usually revealed by a change in PVC colour from white to yellow or dark brown. Thermal stabilizers are used to control PVC thermal degradation. An aspect of the present subject matter disclosed the use of natural-origin thermal stabilizers to produce a thermally stable multi-layered PVC-based material replacing commercial solvent-based stabilizers. Also, the combination with expanding microspheres allows a material which is ADCA free. In an embodiment, the PVC foamed layer is preferably ADCA free and can be produced by the incorporation of chemical or physical blowing agents, more specifically microspheres.

[0063] In an embodiment, the proposed thermal stabilizer was prepared as follows: Eggshell particles/powder.

[0064] In an embodiment, eggshells were treated using a process involving four stages: washing, drying, milling and purification. The raw material was first washed several times under warm water. The washed eggshells were milled into smaller pieces using a porcelain mortar and pestle, and then dried in a vacuum oven at 100° C. for 24 h. Dried eggshells were later milled to a fine powder and passed through a sieve (size from 0.1 and 150 μm) and kept in a desiccator at room temperature. The organic biological matter was removed from eggshells using different approaches, including an acidic treatment, a thermal treatment at different temperatures, and combinations of these approaches. For the acidic treatment, the eggshell powder was immersed in an aqueous solution of acetic acid (0.5 M) until all the organic matter was removed. For the thermal treatment, eggshell powders, previously treated or not with the acidic treatment, were heated from 200° C. to 350° C.

[0065] Surprisingly the properties of eggshell particles, namely a high porosity and high surface area, allows an efficient stabilization capacity as an HCl scavenger, and consequently, high efficiency as a thermal stabilizer.

[0066] In an embodiment, the eggshell powder described herein was isolated from chicken eggs. However, other types of eggshells can be used to yield a similar powder such as shells from turkey eggs, ostrich eggs, geese eggs, quail's eggs, duck eggs, and other bird eggs.

[0067] Other thermal stabilizers can be used combined with eggshell powder, namely calcium and zinc soaps of epoxidized vegetable oils.

[0068] In an embodiment, metal soaps of epoxidized oils were prepared by metathesis in alcoholic solution following two steps: hydrolysis and precipitation. A known amount (0.01 mol) of each EVO—epoxidized vegetable oils (ELO—epoxidized linseed oil and ESO—epoxidized soybean oil) was first dissolved in 50 ml of boiling ethanol and then mixed with 20 ml of sodium hydroxide solution (20% w/v). A solution (100 ml at 30% w/v) of different metal salts (˜0.1 mol) was slowly added to this mixture under continuous stirring (1500 rpm). The zinc metal salts used were zinc acetate (Zn(Ac).sub.2) and zinc sulfate (Zn(SO.sub.4), while the calcium metal salts used were calcium acetate (Ca(Ac).sub.2), calcium nitrate (Ca(NO.sub.3).sub.2), and a mixture of calcium nitrate and calcium hydroxide (Ca(NO.sub.3).sub.2/Ca(OH).sub.2) or mixture of calcium acetate and calcium hydroxide (Ca(Ac).sub.2/Ca(OH).sub.2) (ratio 1:0.05, at the maximum solubility of Ca(OH).sub.2 in the reaction media). The precipitated metal soaps were washed with hot deionized water followed by washing with diethyl ether and dried in a vacuum oven at 50° C. until constant weight is achieved.

[0069] In an embodiment, the heat aging is graded as 4-5, using grey scale according ISO 105-A02:1993/Cor 2:2005. In an embodiment, the heat aging of PVC films (3×2) cm was performed using a ventilated oven at 100° C. for 240 h and 500 h and evaluated through periodic colour measurements. Colour measurements were performed using a Colour Spectrophotometer: film specimens were placed on a white standard plate and the lightness/darkness (L) and chromaticity parameters “a” (red-green) and “b” (yellow-blue) were measured. Grey scale result is the evaluation of differences in colour shading of a material's appearance. Grey scale is used in the assessment of change in colour, occurring in both heat aging testing, as described in ISO 105-A02:1993/Cor 2:2005. A tool, known as a grey scale, is used to visually assess and compare the loss of colour of a specimen by identifying a half-step rating of 5 to 1. The half-step scale consists of pairings of grey colour, from 5 being good to 1 being poor. This grey scale includes also half-step scale values. Using the Spectrophotometer, three measurements were taken on different locations of each sample (3×2 cm) and the averages were used for data analysis. DL, Da, and db are the difference of initial and final values of “L”, “a”, and “b” during heat aging experiments.

[0070] In an embodiment, the eggshell was milled and passed through a sieve up to 200 μm, after drying in vacuum oven at 60° C. Subsequently, a thermal treatment was performed, and, during cooling, the eggshell was stored in a desiccator with silica. All eggshell powder characterization was performed afterwards. As revealed in the particle size distribution graphic, the particle size ranges from 0.1 to 200 μM, confirming the presence of granules/agglomerates/clusters. This fact is also confirmed by the SEM images on FIG. 2.

TABLE-US-00001 TABLE 1 Eggshell powder properties Property Treated Eggshell Appearance Light yellow Real density (g .Math. cm.sup.3) 2.74 ± 0.01 Bulk density (g .Math. cm .sup.3) 0.67 Total pore area (m.sup.2 .Math. g.sup.−1) 2.78 Pore volume (cm.sup.3 .Math. g.sup.−1) 1.03 × 10.sup.−2 BET surface area (m.sup.2 .Math. g.sup.−1) 2.80 ± 0.04 d.sub.10 (μm) 3.85 ± 0.08 d.sub.50 (μm) 15.6 ± 0.60 d.sub.90 (μm) 68.3 ± 3.41 % organic matter* 0.81 *Measured by TGA

[0071] In an embodiment, for a better incorporation in the PVC paste, the eggshell powder was previously dispersed into the plasticiser. However, to improve the dispersion, an extra milling was performed. This paste homogenization is crucial as it allows uniform and fluid distribution of the PVC paste in the paper substrate and it will avoid the appearance of mechanical defects on the final material (see FIG. 3).

[0072] In an embodiment, obtaining the PVC thermal stabilizer [0073] Prepare the dispersion of eggshell powder in the plasticizer (base paste); [0074] Milling the base paste to destroy the eggshell clusters; [0075] Add the base paste to the PVC paste (PVC resin+Plasticizer+Additives); [0076] Filter the prepared PVC paste; [0077] Milling the PVC paste (optional); [0078] For a maximum particle size/particle size of 200 μM eggshell powder (as tested) it is found that the milling of the paste (eggshell powder+plasticizer) allows removing the eggshell clusters from the final PVC film.

[0079] In an embodiment, in FIG. 3 the positive influence of the extra milling of the eggshell on the quality of the PVC film is visible, with the destruction of the formed clusters.

[0080] In an embodiment, the eggshell powders were characterized for their true density, pore size distribution, surface area, particle size distribution and morphological structure. The true density of the particles was measured by helium pycnometry (Accupyc 1330 Micromeritics, Micromeritics Instrument, USA). The pore size distribution, total pore area and bulk density of the particles were measured by mercury porosimetry (Autopore IV Micromeritics, Micromeritics Instrument, USA) after purging the samples for 5 minutes at 50 μm Hg to remove adsorbed water and other impurities. The surface area and the pore volume of the particles were determined by nitrogen adsorption (Micromeritics, model ASAP 2000, 20Q-34001-01) using the Brunauer-Emmett-Teller (BET) method and Barrett-Joyner-Halenda (BJH) method, respectively. The average particle size and size distribution of the particles were measured by Laser Diffraction Spectroscopy (LDS) (Mastersizer 2000, Malvern Instruments, UK) with the solid particles dispersed at 1% (wt/wt) in milli-Q water with 1% (v/v) of Tween® 20. The microstructure of the particles was analyzed by Scanning Electron Microscopy (SEM) (Jeol JSM-5310, Japan) on gold-coated samples with an operating voltage of 10 kV.

[0081] The results of the following tables are based on the following methods: [0082] Volatile Organic Compounds (VOC) and semi-volatile components (FOG): VDA 278:2011; [0083] Semi-volatile components: assessed by DIN 75201-B:2011 and VDA 278:2011; Colour fastness: ISO 105-B06:1998/Amd 1:2002, Cond.3; [0084] Heat aging and thermal stability: Evaluation according ISO 105-A02:1993/Cor 2:2005.

TABLE-US-00002 TABLE 2 Colour fastness of the evaluated composites/materials Colour Fastness 1 cycle 3 cycles 5 cycles ≥7 grade ≥4 grade ≥4 grade Ref. Db* Grade Db* Grade Db* Grade Version 0 −0.10 7 0.03 4-5 0.10 4-5 Version 1 −0.2 7 −0.21 4-5 −0.18 4-5 Version 2 −0.26 7 −0.25 4-5 −0.07 4-5 Version 3 −0.17 7 −0.09 4-5 0.02 4-5 Version 0 - Reference version: Composite structure that is formed by PVC layer, PVC foam layer, PVC adhesive layer and knitted fabric support layer. All the PVC-based layers comprising calcium/zinc stabilizers. Version 1 - Composite structure with eggshell in PVC layer. Version 2 - Composite structure with eggshell in all layers, namely PVC layer and intermediate layers. Version 3 - Composite structure with eggshell in all layers; and polymeric microspheres in the PVC foam and adhesive layer.

TABLE-US-00003 TABLE 3 Heat aging properties of the evaluated composites/materials Heat Aging 240 h @ 100° C. ≥4 grade 500 h @ 100° C. Ref. Db* Grade Db* Grade Version 0 0.96 4 1.26 4 Version 1 0.69 4-5 0.85 4-5 Version 2 0.73 4-5 0.32 4-5 Version 3 1.71 4 4.02 2-3 Version 0 - Reference version: Composite structure that is formed by PVC layer, PVC foam layer, PVC adhesive layer and knitted fabric support layer. All the PVC-based layers comprising calcium/zinc stabilizers. Version 1 - Composite structure with eggshell in PVC layer. Version 2 - Composite structure with eggshell in all layers, namely PVC layer and intermediate layers. Version 3 - Composite structure with eggshell in all layers; and polymeric microspheres in the PVC foam and adhesive layer.

TABLE-US-00004 TABLE 4 VOCs/FOGs emissions of the evaluated composites/materials Percentage of emissions compared to Version 0 VDA 278: 2011 (wt %) Ref. VOC FOG Version 0 0 0 Version 2 −8.5 −10.7 Version 0 - Reference version: Composite structure that is formed by PVC layer, PVC foam layer, PVC adhesive layer and knitted fabric support layer. All the PVC-based layers comprising calcium/zinc stabilizers. Version 1 - Composite structure with eggshell in PVC layer. Version 2 - Composite structure with eggshell in all layers, namely PVC layer and intermediate layers. Version 3 - Composite structure with eggshell in all layers; and polymeric microspheres in the PVC foam and adhesive layer.

[0085] In an embodiment, the incorporation of eggshell particles does not impair light fastness since materials incorporating eggshell particles have a similar result to the reference material.

[0086] In an embodiment, the incorporation of the eggshell substantially favors the thermal aging of the materials since it has lower db values than the reference material. The material of version 2 presents a 4-5 grade in thermal aging while the Version 0 presents a 4 grade. The visual evaluation of the test pieces after aging is carried out according to the grey scale (ISO 105-A02:1993/Cor 2:2005) comparing with non-aged specimen and placed side by side, on a metal plate with an angle of 45°, centred on the laboratory light chamber (on illuminant D65) and comparing with the grey scale.

[0087] In an embodiment, the eggshell incorporation induces a slight decrease in the Volatile Components Emission (VOC) according to VDA 278:2011 and induces a substantial decrease in the emission of semi-volatile components (FOG) assessed by DIN 75201-B:2011 and VDA 278:2011, compared to the standard material.

[0088] Furthermore, where the claims recite a composition, it is to be understood that methods of using the composition for any of the purposes disclosed herein are included, and methods of making the composition according to any of the methods of making disclosed herein or other methods known in the art are included, unless otherwise indicated or unless it would be evident to one of ordinary skill in the art that a contradiction or inconsistency would arise.

[0089] Where ranges are given, endpoints are included. Furthermore, it is to be understood that unless otherwise indicated or otherwise evident from the context and/or the understanding of one of ordinary skill in the art, values that are expressed as ranges can assume any specific value within the stated ranges in different embodiments of the invention, to the tenth of the unit of the lower limit of the range, unless the context clearly dictates otherwise. It is also to be understood that unless otherwise indicated or otherwise evident from the context and/or the understanding of one of ordinary skill in the art, values expressed as ranges can assume any subrange within the given range, wherein the endpoints of the subrange are expressed to the same degree of accuracy as the tenth of the unit of the lower limit of the range.

[0090] The disclosure should not be seen in any way restricted to the embodiments described and a person with ordinary skill in the art will foresee many possibilities to modifications thereof.

[0091] The above described embodiments are combinable.

[0092] The following claims further set out particular embodiments of the disclosure.