FILM HAVING A WOOD-LIKE APPEARANCE

Abstract

The invention relates to a film having a wood-like appearance and having a width from 0.1 to 6 m, a length of 2 to 10,000 m, a thickness from 180 to 1,000 m and formed from, a material which contains, relative the total weight thereof 40 to 85 wt % of vinylchloride polymerizate, 10 to 60 wt % of a powder made from vegetable components, 0 to 30 wt % of one or more inorganic filler substances, and 5 to 30 wt % of one or more additives.

Claims

1. Film made of a material composed of, based on its total weight, from 40 to 85% by weight of vinyl chloride polymer, from 10 to 60% by weight of rice-husk powder, peanut-shell powder or a mixture of rice-husk and peanut-shell powder, from 0 to 30% by weight of one or more inorganic fillers and from 5 to 30% by weight of one or more additives, wherein the width of the film is from 0.1 to 6 m, its length is from 2 to 10 000 m and its thickness is from 180 to 1000 m.

2. Film according to claim 1, wherein the length of the film is from 10 to 10 000 m or from 100 to 10 000 m.

3. Film according to claim 1, wherein the arithmetic average roughness value Ra of a first surface of the film is from 3 to 20 m.

4. Film according to claim 1, wherein the arithmetic average roughness value Ra of a second surface of the film is from 3 to 50 m.

5. Film according to claim 1, wherein at least one surface of the film has been embossed.

6. Film according to claim 1, wherein the inorganic fillers are selected from chalk, talc, mica, alumina, kaolin, silicates and titanium oxide.

7. Film according to claim 1, wherein the additives are selected from processing aids, heat stabilizers, lubricants, polymeric modifiers, dyes, pigments, fungicides, UV stabilizers, fire-protection agents and fragrances.

8. Film according to claim 1, wherein the material comprises, based on its total weight, from 1 to 6% by weight of one or more lubricants selected from waxes, fats, paraffins, epoxidized soya oil and acrylate-based polymers.

9. Film according to claim 1, wherein the material comprises, based on its total weight from 3 to 12% by weight of one or more polymeric modifiers selected from acrylate-, butyl-methacrylate-, methacrylate-butyl-styrene-, methyl-methacrylate-butadiene-styrene- and chlorinated-polyethylene-based polymers.

10. Film according to claim 1, wherein the flow exponent n of the material at a temperature of 190 C. is from 0.05 to 0.36.

11. Film according to claim 1, wherein the particle size of the powder made of rice husks and/or of peanut shells is from 10 to 250 m.

12. Film according to claim 1, wherein the powder made of rice husks and/or of peanut shells comprises silane groups with the structural formula I and/or II ##STR00002## where R is a group selected from NH.sub.2(CH.sub.2).sub.3 and (CH.sub.3CH.sub.2).sub.2.

13. Film according to claim 1, wherein the powder made of rice husks and/or of peanut shells has been acetylated with a weight increase of from 9 to 25%, based on the weight of the powder before acetylation.

14. Film according to claim 1, wherein a lamination film has been laminated onto at least one surface of the film, where the lamination film is composed of a material comprising, based on its total weight, from 70 to 98% by weight of a polymer selected from polyethylene and polyester.

15. Process for the production of a film comprising the steps of (a) providing a material composed of based on its total weight, from 40 to 85% by weight of vinyl chloride polymer, from 10 to 60% by weight of rice-husk powder, peanut-shell powder or a mixture of rice-husk and peanut-shell powder, from 0 to 30% by weight of one or more inorganic fillers and from 5 to 30% by weight of one or more additives; (b) plasticizing the material in a gelling assembly where the material is heated to a temperature of from 160 to 190 C.; (c) moulding the material plastified in step (b) to give a Him of width from 0.1 to 6 m, length from 2 to 10 000 m and thickness from 180 to 1000 m; wherein the material provided in step (a) at a temperature of from 190 C. has a flow exponent, n from 0.05 to 0.36; and step (c) further comprises calendering the plastified material on a roll calender, where the material passes through a shaping nip and forms an accumulation of material of height from 5 to 30 mm in advance of the nip the surface temperature of the two rolls forming the shaping nip, mutually independently, is from 150 to 220 C. the rolls rotate with a peripheral velocity of from 20 to 80 m/min and the ratio of the peripheral velocities of the two rolls is from 1.0 to 1.2.

16. Process for the production of a film according to claim 15, wherein the plastified material is calendered in step (c) on a roll calender where the material passes through a shaping nip and forms a bank of height from 5 to 20 mm.

17. Process for the production of a film according to claim 15, wherein the surface temperatures Ta and Tb of the two rolls forming the shaping nip comply with the relationship 10 C.TaTb40 C., where Ta is the surface temperature of the first roll in the direction of running of the film and Th is the surface temperature of the second roll in the direction of running of the film.

18. Process for the production of a film according to claim 15, wherein the process further comprises drawing off the film moulded in step (c) from the roll calender by means of one, two or more take-off rolls, where the peripheral velocity of a take-off roll that is first in the direction of running of the film is from 1.005 times to 1.1 times the peripheral velocity of the shaping-nip roll that is second in the direction of running of the film.

19. Process for the production of a film according to claim 15, wherein the process further comprises drawing off the film moulded in step (c) from the roll calender by means of two or more take-off rolls, where the peripheral velocity of a take-off roll that is first in the direction of running of the film is from 1.005 times to 1.1 times the peripheral velocity of a take-off roll that is downstream in the direction of running of the film.

20. Process for the production of a film according to claim 15, wherein the roll calender comprises one or more embossing rolls and at least one surface of the film moulded in step (c) is embossed by means of the embossing roll.

21. Process for the production of a film according to claim 15, wherein said process further comprises laminating a lamination film onto a surface of the firm moulded in step (c), where the lamination film is composed of a material comprising, based on its total weight, from 70 to 98% by weight of a polymer selected from polyethylene and polyester.

Description

[0072] The invention is explained in more detail below with reference to Figures and Examples.

[0073] FIGS. 1 and 2 are sectional views of a single- and two-layer film of the invention;

[0074] FIG. 3 is a block diagram of a calender device for the production of a single-layer film;

[0075] FIGS. 4 and 5 are diagrams of parts of calender devices; and

[0076] FIG. 6 is a sectional view of a shaping nip of a calender device.

[0077] FIGS. 1 and 2 are diagrammatic sectional views of a single-layer film 1 of the invention made of FPC material and respectively, a film 1 made of FPC material coated with a lamination film 2. The lamination film 2 is composed of a material that comprises, based on its total weight, from 70to 98% by weight of a polymer selected from polyethylene and polyester.

[0078] FIG. 3 is a diagram of a calender device conventionally used in industry with a gelling assembly, a roll calender, conditioning and optionally embossing rolls, and also a winding unit. An FPC material in the form of powder or of granules is introduced by way of an associated mixer into the gelling assembly. According to the invention, the composition of the FPC material introduced into the gelling assembly is precisely controlled in order to ensure that the rheological properties of the plastified material are substantially constant, and that any variations are within a narrow tolerance range. Production of the film of the invention can use any desired calender devices with configuration differing from FIG. 3, as explained, below in connection with FIGS. 4 and 5. In particular, calender devices comprising one or two lamination units are envisaged.

[0079] FIG. 4 is a simplified view of part of a calender device with a gelling assembly 11 for the plastification of the FPC material of the invention, conveying equipment 12 and a roll calender 13. An extruder or kneader is envisaged as gelling assembly 11. Suitable extruders and kneaders known to the person skilled in the art can be purchased from various manufacturers. The FPC material 6 plastified in the gelling assembly 11 is transferred by means of the conveying equipment 12 onto the roll calender 13 and moulded to give a film 8. The FPC material located in the roll calender 13 is indicated, by the numeral 7 in FIG. 4. The roll calender 13 comprises from two to eight, preferably four, calender rolls (14, 15, 16, 17), and also one or more embossing and cooling rolls not shown in FIG. 4. The calender device has optionally been equipped with one or more lamination units not shown in FIG. 4. The calender device moreover comprises a winding unit not shown in FIG. 4. The arrangement of the four calender rolls (14, 15, 16, 17) of the roil calender 13 shown in FIG. 4 is termed inverted L configuration. The axes of the calender rolls (14, 15, 16, 17) are in essence parallel to one another. The calender rolls (14, 15, 16, 17) are driven and rotate around their longitudinal axes, the direction of rotation of each of two adjacent rolls 14 and 15, 14 and 16 and 16 and 17 being mutually opposed.

[0080] Each of the calender rolls 14, 15, 16 and 17 has an associated temperature-control device, and can be cooled or heated independently of the other calender rolls. The temperature of the calender rolls (14, 15, 16, 17) is controlled by means of a fluid, in particular by means of water or oil. The temperature-controlled fluid is introduced to, and removed from, each of the calender rolls 14, 15, 16 and 17 by way of passages within the bearing axis.

[0081] In the roll calender 13, the plastified FPC material 7 passes through one or more nips delimited by the curved surface of adjacent rolls 14 and 15, 14 and 16 and 16 and 17. The thickness of the film 8 moulded from the FPC material is determined via the narrowest nip 10, known as the shaping nip. The shaping nip 10 is preferably formed by the two final calender rolls (16, 17) of the roll calender 13. The diameters of the calender rolls 16 and 17 which form the shaping nip 10 are from 400 to 900 mm.

[0082] The position of the rotary bearings of one or more of the calender rolls (14, 15, 16, 17), in particular of the calender rolls 17 and/or 16 forming the shaping nip 10, can be adjusted with the aid of hydraulic or electrical actuators with an accuracy of a few micrometres. The size of the shaping nip 10 can therefore be adjusted precisely to the technical requirements of the process. The expression shaping nip height is conventional in the art and is used hereinafter for the size of the shaping nip.

[0083] FIG. 5 is a view of part of a calender device which differs from the device shown in FIG. 4 only in the configuration of the roll calender 13. The meaning of the other reference signs in FIG. 5 is the same as described above in connection with FIG. 4. The configuration of the roll calender 13 shown in FIG. 5 is termed Z configuration by persons skilled in the art.

[0084] For the purposes of the invention, alternative configurations with from two to eight, preferably four, calender roils by way of example in I configuration. S configuration or L configuration are envisaged alongside the roll calenders 13 (inverted L configuration) and 13 (Z configuration) shown in FIGS. 4 and 5.

[0085] The properties of the film of the invention made of FPC material are determined practically exclusively via the operating parameters of the two calender roils that form the shaping nip.

[0086] FIG. 6 is a diagrammatic sectional view of a shaping nip 10 formed by two calender rolls 16 and 17. The curved surfaces of the calender rolls 16 and 17, rotating in opposite directions, delimit the nip 10, and the reference sign h here indicates the minimal distance between the curved surfaces of the calender rolls 16 and 17 or the shaping nip height. The rotary bearings, not shown in FIG. 6, of the calender rolls 16 and/or 17 can be moved in one or two spatial directions, for example vertically and/or horizontally, over a positioning range of a few millimetres with an accuracy of a few micrometres. It is accordingly possible to achieve precise adjustment of the shaping nip height h. The reference signs v.sub.1 and, respectively, v.sub.2 indicate the peripheral velocities of the calender rolls 16 and 17, where the peripheral velocity of the calender roll 17 is greater than or equal to the peripheral velocity of the calender roll 16, i.e. v.sub.1v.sub.2.

[0087] FIG. 6 moreover depicts the plastified FPC material 7 introduced into the shaping nip 10 and the film 8 moulded therefrom with thickness d. The thickness d and the width b of the film 8 depend on the quantity or mass of plastified FPC material 7 introduced per unit of time into the nip 10, and on the peripheral velocities v.sub.1 and v.sub.2 of the calender rolls 16 and, respectively, 17. By virtue of conservation of mass, the mass of film 8 produced per unit of time is the same as the mass of plastified FPC material 7 introduced per unit of time. It is preferable that the plastified FPC material 7 is introduced into the shaping nip 10 in the form of a web with thickness d.sub.1 and width b.sub.1. By virtue of conservation of mass, the relationship v.sub.1d.sub.1b.sub.1=v.sub.2db then holds. The ratio of the width b of the film 8 to the width b.sub.1 of the web made of plastified FPC material 7 introduced into the nip is preferably in the range 1.0.Math.b.sub.1b<1.2.Math.b.sub.1 and is particularly preferably in the range 1.0.Math.b.sub.1b1.1.Math.b.sub.1, i.e. the extent to which the web made of plastified FPC material 7 introduced into the shaping nip 10 is widened is up to 20% and, respectively, up to 10%. The length of the film 8 produced per unit of time corresponds to the peripheral velocity v.sub.2, and is also termed production velocity. The height h of the shaping nip 10 is adjusted as a function of the selected thickness d of the film 8 in such a way as to comply with the relationship hd.

[0088] The diagram in FIG. 6 moreover shows the accumulation of material 7 which forms in advance of the shaping nip 10 in relation to the direction of conveying of the plastified FPC material 7. The term bank is also used by persons skilled in the art for the accumulation 7 of material in advance of the nip. The accumulation 7 of material in advance of the nip arises because some of the FPC material 7 introduced is deflected before the shaping nip 10 and passes through one or more zones of turbulence before being transported by the curved surface of the calender roll 17 through the shaping nip 10. The volume of the accumulation 7 of material in advance of the nip is determined to a decisive extent by the height h of the shaping nip 10. The volume of the accumulation of material 7 increases with decreasing height h of the shaping nip 10 and vice versa. The shaping nip 10 can be regarded as retarding the plastified FPC material 7, the extent of the said retardation increasing with decreasing height h. The volume of the accumulation 7 of material in advance of the nip is minimal for h=d. The height of the accumulation 7 of material in advance of the nip, or of the bank 7, is indicated in FIG. 6 by the reference sign h.sub.1.

[0089] The peripheral velocities v.sub.1 and v.sub.2 and the temperatures of the shaping calender rolls 16 and 17, and also the height h of the nip 10, are of decisive importance for the properties of a film 8 with thickness d produced from FPC material of the invention. It is necessary here to balance the above calender parameters with the rheological properties of the respective FPC material used, in particular the flow exponent n thereof. In principle, the diameter of the shaping calender rolls 16 and 17 also influences the properties of the resultant film 8. However, for the calender rolls envisaged for the purposes of the present invention with diameter conventional in industry in the range from 400 to 900 mm, the influence of the roll diameters is negligible.

[0090] For the purposes of the present invention, the expressions first roll or upstream roll and, respectively, second roll or downstream roll indicate the arrangement of the relevant roll relative to another roll in relation to the direction of running of the film in the calender device. By way of example, with reference to FIGS. 4, 5 and 5 the two rolls 16 and 17 forming the shaping nip 10 are termed first roll 16 and, respectively, second roll 17. Analogous considerations apply to a take-off device envisaged according to the invention with two or more take-off rolls, where the expressions first take-off roll or upstream take-off roll and, respectively, second take-off roll or downstream take-off roll indicate the arrangement of the relevant take-off roll relative to another take-off roil in relation to the direction of running of the film in the calender device.

[0091] The test methods used to characterize the FPC material of the invention and the films produced therefrom are described below.

[0092] The tensile strength and tensile strain at break of the films are determined in accordance with DIN EN ISO 527:2012, tensile impact resistance is determined in accordance with DIN EN ISO 8256:2005, density is determined in accordance with DIN EN ISO 1183:2005 and thickness is determined in accordance with DIN 53370:2006.

[0093] The flow exponent n of the FPC material is determined in accordance with DIN EN ISO 1133 at a temperature of 190 C. with use of a standard nozzle with diameter 2.035 mm and length 8 mm. Five tests are carried out with applied weights of 2.16 kg, 5.0 kg, 10.0 kg, 15.0 kg and 21.6 kg, corresponding to shear stresses of 1.96510.sup.4 Pa, 4.54810.sup.4 Pa, 9.09610.sup.4 Pa, 1.36410.sup.5 Pa and 1.96510.sup.5 Pa, and the respective melt volume flow rate Q is determined. The associated (apparent) shear velocity is calculated on the basis of the melt volume flow rate Q in accordance with the relationship

[00001]${}_a=\begin{array}{c}4.Math.Q\\ .Math..Math.R^3\end{array}$

where R=1.0475 mm. Accordingly, {dot over ()} .sub.a=1.108 .Math.Qmm.sup.3.

[0094] The viscosity =/{dot over ()} .sub.a is calculated from the shear velocity {dot over ()} .sub.a and the associated shear stress . In accordance with the Ostwald-de Waele power law, the following relationship links viscosity to shear velocity {dot over ()} .sub.a:

=K.Math.{dot over ()} .sub.a.sup.n1

where K is the flow consistency index and n is the flow exponent. When both sides of this equation are presented as logarithms, a linear relationship is obtained:

log()=log(K)+(n1).Math.log({dot over ()} .sub.a)

and this permits determination, via linear regression, of the flow consistency index K and the flow exponent n on the basis of the test results for the melt volume flow rates with the abovementioned five applied weights and, respectively, shear stresses.

[0095] The arithmetic average roughness value Ra of the surfaces of the film of the invention is determined by means of a tactile profilometer, for example with a Hommel-Etamic W20 instrument from Jenoptik. The test is carried out in accordance with the standards DIN EN ISO 4287:2010and DIN EN ISO 16010:2013. The radius of the sensor tip used here is less than 5 m. The total traversed distance Lt=5lr for each roughness test, inclusive of pre- and post-traverse distance, is greater than 15 mm. The value used as limiting wavelength .sub.c for the low-pass filter used to separate roughness and corrugation in accordance with DIN EN ISO 16610:2013 is .sub.c=2.5 mm; the length of the five individual traverses lr is accordingly lr=2.5 mm (lr=.sub.c).

[0096] According to the invention, the dimensions of microscale particles or agglomerates are determined by using a scanning electron microscope or transmission electron microscope and image analysis software, for example ImageJ (http://imagej.nih.gov/ij). Digitalized electron micrographs are used here for digital measurement, of at least 100, preferably at least 1000, particles or agglomerates with the aid of the image analysis software. Owing to the high lateral resolution of electron microscopes of the prior art, which is in the range from a few angstroms up to 10 nm, depending on the setting of the electron optics and of the parameters of the beam, it is possible to determine the equivalent diameter of the particles or agglomerates with high reliability. Alternatively or in addition, the dimensions of microscope particles or agglomerates are measured by means of light scattering. Test, equipment, suitable for this purpose for particle sizes from 0.01 to 5000 m is available for purchase inter alia from Horiba Ltd, (Kyoto, Japan) as product LA-300.