FILM BASED ON A COMPOSITION OF POLYMERS AND PLASTICIZERS HAVING A TG RANGING FROM -35°C TO 40°C, ELEMENT INCORPORATING SAID FILM, METHOD FOR MANUFACTURING THEREOF AND USES THEREOF

Abstract

Disclosed is a film based on a composition including at least one polymer and at least one plasticizer, the composition having a calculated Tg ranging from 35 C. to 40 C., preferably from 20 C. to 10 C., the film presenting a rebound resilience according to Test A less than 15%, preferably less than 10%; to a process for its manufacturing and to its uses; it also relates to an element incorporating the film and uses thereof.

Claims

1. A film based on a composition comprising at least one polymer (k) and at least one plasticizer (i), said composition having a calculated Tg ranging from 35 C. to 40 C., said film presenting a rebound resilience according to Test A less than 15%, the calculated Tg being the Tg value estimated for miscible polymers by Fox theory, according to the following equation: $\frac{1}{\mathrm{Tg}}=\underset{i=1}{\overset{j=10}{.Math.}}.Math..Math.\frac{x_i}{{\mathrm{Tg}}_i}+\underset{k=1}{\overset{l=20}{.Math.}}.Math..Math.\frac{x_k}{{\mathrm{Tg}}_k}$ $\mathrm{with}$ $\underset{i=1}{\overset{j=10}{.Math.}}.Math..Math.x_i+\underset{k=1}{\overset{l=20}{.Math.}}.Math..Math.x_k=100$ Tg.sub.i being the measured Tg of each plasticizer i; x.sub.i being the relative weight amount of each plasticizer i; x.sub.k being the relative weight amount of each polymer k; Tg.sub.k being the measured Tg of each polymer k, Tg being measured from a dynamic mechanical analysis test (DMA) and being the maximum of tangent delta peak at 2 Hz.

2. The film according to claim 1, wherein it is based on a composition comprising at least one polymer which is selected from polymers or co-polymers with a Tg ranging from 70 C. to 100 C. and a tan delta of at least 0.9, and at least one plasticizer, a cross-linking system, an additive and/or mixtures thereof.

3. The film according to claim 1, wherein the polymer is selected from polynorbornene, polybutadiene polyacrylonitrile, polychloropropene, poly(ethylene vinylacetate), poly(vinyl acetate), poly(vinyl acetate-vinyl chloride), polyvinylchloride, butyl rubber, chlorinated isobutylene-isoprene copolymer and mixtures thereof.

4. The film according to claim 1, wherein the plasticizer is selected from oils such as paraffinic oil, naphthenic oil, aromatic oil, petroleum resins, terephthalate, silicon oil; classical plasticizers for plasts such as phthalates, epoxides, aliphatic acid diesters, polyesters (adipates, citrates, etc.), phosphates; or liquid polymers such as liquid polymers from butadiene or Silicone; and mixtures thereof.

5. The film according to claim 1, wherein the composition comprises: 15 to 98% of at least one polymer with a Tg ranging from 70 C. to 100 C. and a tan delta of at least 0.9, preferably at least 1.5 preferably at least 2; 1 to 85%, preferably 20 to 70% of at least one plasticizer; 0 to 20%, preferably 1 to 5%, of a filler; 0 to 5%, preferably 0.5 to 2%, of a vulcanization system; 0 to 5%, preferably 0.5 to 4%, of an additive selected from colorant, protective agent, flame retardant, tackiness regulator, and mixtures thereof.

6. The film according to claim 1, wherein the thickness of the film ranges from 0.1 to 10 mm, preferably from 0.2 to 4 mm, and still more preferably may be 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, 1.2 mm, 1.6 mm, 2.0 mm or 2.4 mm.

7. The film according to claim 1, which presents an elongation at break measured according to DIN 53504 of at least 10%, preferably at least 100% and even more preferably at least 300%.

8. A process for manufacturing a film according to claim 1, comprising: providing a composition comprising at least one polymer and at least one plasticizer, said composition having a calculated Tg ranging between 35 C. and 40 C., preferably from 20 C. to 10 C.; optionally adding to said composition a filler, a cross-linking system, an additive and/or mixtures thereof; stretching said composition into a film in a calender at 20 to 120 C., preferably at 30 to 100 C. preferably 40 to 90 C.; optionally heating the film at a temperature ranging from 100 C. to 250 C., preferably from 110 C. to 200 C., and even more preferably from 150 C. to 170 C. if vulcanization is needed.

9. The process of claim 8, wherein it further comprises a surface treatment step, in which at least one of the film's surface is treated to modify its tackiness.

10. An element incorporating at least one film as defined in claim 1.

11. The element according to claim 10 which is a multilayer film.

12. A material for protecting products which are very sensitive to impacts and/or vibrations, such as dishes, decorative objects, electronic devices, printed circuit boards, etc, comprising the film of claim 1.

13. A coating applied on a device or part of a device which is submitted to vibrations, comprising the film of claim 1.

14. A material for wrapping around the grip part of sport devices or machines, in order to limit the vibrations transmitted to a person who holds this grip part, comprising the film of claim 1.

15. The film of claim 1, wherein the film has a calculated Tg ranging from 20 C. to 10 C.

16. The film of claim 15, wherein the film presents a rebound resilience according to Test A less than 10%.

17. The film of claim 2, wherein the tan delta is at least 1.5.

18. The film of claim 2, wherein the tan delta is at least 2.

19. The film of claim 2, wherein the composition further comprises a filler.

20. The film of claim 5, wherein the composition comprises 30 to 80% of the at least one polymer with a Tg ranging from 70 C. to 100 C. and a tan delta of at least 0.9.

Description

DETAILED DESCRIPTION

[0028] The invention thus relates to a film based on a composition comprising at least one polymer (k) and at least one plasticizer (i), the composition having a calculated glass transition temperature (Tg) ranging between 35 C. and 40 C., preferably from 20 C. and 10 C., said film presenting a maximum rebound according to Test A less than 15%, preferably less than 10%,

[0029] Tg being measured from a dynamic mechanical analysis test (DMA) and being the maximum of tangent delta peak at 2 Hz,

[0030] the calculated Tg being the Tg value estimated for miscible polymers by Fox theory, according to the following equation:

[00001]$\frac{1}{\mathrm{Tg}}=\underset{i=1}{\overset{j=10}{.Math.}}.Math..Math.\frac{x_i}{{\mathrm{Tg}}_i}+\underset{k=1}{\overset{l=20}{.Math.}}.Math..Math.\frac{x_k}{{\mathrm{Tg}}_k}$$\mathrm{with}$$\underset{i=1}{\overset{j=10}{.Math.}}.Math..Math.x_i+\underset{k=1}{\overset{l=20}{.Math.}}.Math..Math.x_k=100$

Tg.sub.i being the measured Tg of each plasticizer i;
x.sub.i being the relative weight amount of each plasticizer i;
x.sub.k being the relative weight amount of each polymer k;
Tg.sub.k being the measured Tg of each polymer k.

[0031] In the composition on which the film is based, the polymer is selected from polymers or co-polymers with a Tg ranging from 70 C. to 100 C. and a loss factor (tan delta) of at least 0.9, preferably at least 1.5, even more preferably at least 2. Examples of such polymers or co-polymers are polynorbornene, polybutadiene polyacrylonitrile, polychloropropene, poly(ethylene vinylacetate), poly(vinyl acetate), poly(vinyl acetate-vinyl chloride), polyvinylchloride, butyl rubber, chlorinated isobutylene-isoprene copolymer. In the present application, the term polymer includes polymers and co-polymers, unless otherwise specified.

[0032] Only one of said polymer may be used or mixtures of said polymers may be used. Said mixtures may include from 2 to 20 different polymers, in particular 3, 4, 5, 6, 7, 8, 9, or 10 different polymers.

[0033] In the composition on which the film is based, the plasticizer is selected among plasticizers which are compatible with the polymers mentioned above.

[0034] In the meaning of the present invention, by plasticizer it is meant any plasticizer conventionally used with polymers but also oils and liquid polymers which function as plasticizers in the composition of the invention. In a specific embodiment, the plasticizer can be selected from oils such as paraffinic oil, naphthenic oil, aromatic oil, petroleum resins, terephthalate, silicon oil; classical plasticizers for plasts such as phthalates, epoxides, aliphatic acid diesters, polyesters (adipates, citrates, etc.), phosphates; or liquid polymers such as liquid polymers from butadiene or silicone; and mixtures thereof.

[0035] As an example of classical non-phthalate plasticizers, bis(2-ethylhexyl) ester marketed for example under the trademark Eastman 168 can be cited.

[0036] As examples of classical phthalate plasticizers, bis-(2-ethylhexyl) phthalat (DEHP), bis-(methoxyethyl) phthalate (DMEP), butylbenzyl phthalate (BBP), dibutyl phthalate (DBP), diethyl phthalate (DEP); di-isodecyl phthalate (DIDP); diisononyl phthalate (DINP), diisopentyl phthalate (DiPP), di-n-octyl phthalate (DNOP), di-n-pentyl phthalate (DnPP), can be cited.

[0037] Only one of said plasticizers may be used or mixtures of said plasticizers may be used. Said mixtures may include 2, 3, 4, 5, 6, 7, 8, 9 or 10 different plasticizers, preferably 2, 3, 4 or 5. More plasticizers could be used, however, it would increase the cost without further enhancing the final properties of the film.

[0038] In addition to the at least one polymer with a Tg ranging from 70 C. to 100 C. and a tan delta of at least 0.9, preferably a least 1.5, even more preferably at least 2, and to the at least one plasticizer, the composition on which the film according to the invention is based, may further comprise at least a filler, a cross-linking system, an additive and/or mixtures thereof.

[0039] The fillers are compounds which improve some physical properties of the film (for example which enhances the strength of the film) and/or lower its cost. Examples of fillers include aluminum oxide, silica, silica minerals such as mica, diatomaceous earth, clay, talc, calcium carbonate, sodium carbonate, wollastonite, vermiculite, pyrophyllite, sauconite, saponite, nontronite, montmorillonite, kaolin diamond, chalk, or mixtures thereof. Clays usable for the adhesive material may be calcined or uncalcined. Clays that may be used as fillers may include clays from the kaolinite, illite, chloritem, smecitite or sepiolite groups, which may be calcinated. The clays may also include minor amounts of other ingredients such as carbonates, feldspaths, micas and quartz. Aramid fibers such as Kevlar can also be used as filler.

[0040] Generally, when a filler is used, the amount thereof ranges from 0 to 20 wt %, preferably from 1 to 15 wt %, more preferably from 2 to 10 wt %.

[0041] In the present application, the amounts are given in wt % with respect to the total weight of the composition.

[0042] The cross-linking system is used to induce and/or regulate the cross-linking, in particular the temperature at which the cross-linking will start and the degree of cross-linking. The amount and nature of cross-linking system will be adapted depending on the desired uses, degree of cross-linking, cross-linking temperature and duration of the cross-linking.

[0043] In the present invention, the cross-linking includes vulcanization, i.e. cases where the cross-linking is induced by the formation of sulphur bridges. Thus the cross-linking system includes the vulcanization systems.

[0044] The cross-linking system includes the cross-linking agent alone or in combination with a cross-linking system regulator, i.e. a system composed of one or several agents which accelerates or reduces the cross-linking. Examples of cross-linking agents are peroxides, aromatic amines, vulcanization agents such as sulphur or compounds able to form sulphur linkage such as, for example, tetramethylthiuramdisulfid (TMTD), 2-morpholinodithiobenzothiazol (MBDL), dipentamethylenthiuramtetrasulfid (DPTT), tetraethylthiuramdisulfid (TETD), caprolactamdisulfid (CLD), 4,4-dithiodimorpholin (DTDM).

[0045] Generally the amount of cross-linking agent ranges from 0 to 5 wt %, preferably from 0.5 to 4 wt %, more preferably 1 to 3 wt %.

[0046] Examples of cross-linking agent regulators are N-cyclohexyl-2-benzothiazol (CBS), bis(N,N-dimethyl-thiocarbamyl), 2,2-dibenzothiazyldisulfide (MBTS), tetramethylthiuramdisulfide (TMTD), stearic acid, MgO, metal oxides such as TiO.sub.2, ZnO, etc., or mixtures thereof. One particular example of a vulcanization agent regulator which accelerates the vulcanization is sold under trademark Deovulk EG 3, commercially available from King Industries or DOG deutch Oelfabrik. Other examples of cross-linking agent regulators are compounds able to form sulphur linkage cited previously. tetramethylthiuramdisulfid (TMTD), 2-morpholinodithiobenzothiazol (MBDL), dipentamethylenthiuramtetrasulfid (DPTT), tetraethylthiuramdisulfid (TETD) accelerates vulcanization compared to sulphur whereas caprolactamdisulfid (CLD), 4,4-dithiodimorpholin (DTDM) slow down vulcanization compared to sulphur.

[0047] Generally, when a cross-linking agent regulator is used, its amount ranges from 0.01 to 3 wt %, preferably from 0.1 to 1.5 wt %, more preferably 0.2 to 1 wt %.

[0048] Additives which are used in the composition on which the film according to the invention is based are well known in the polymer field and are used when specific uses and/or properties are desired.

[0049] These additives include but are not limited to an antioxidant, a UV resistant agent, an antiozonant, a flame retardant, a heat stabilizer, a hydrophobic agent, a water absorbent, a colorant, tackiness regulator, a processing aid, a lubricant, a reinforcement (e.g., chopped or continuous glass, ceramic, aramid, or carbon fiber, particulates or the like).

[0050] According to a specific embodiment, the film according to the invention is based on a composition comprising: [0051] 15 to 98%, preferably 30 to 80% of at least one polymer with a Tg ranging from 70 C. to 100 C. and a loss factor (tan ) of at least 0.9, preferably of at least 1.5 and even more preferably of at least 2 to 85%, preferably 20 to 70% of at least one plasticizer; [0052] 0 to 20%, preferably 1 to 5%, of a filler; [0053] 0 to 5%, preferably 0.5 to 2%, of a vulcanization system; [0054] 0 to 5%, preferably 0.5 to 4%, of an additive selected from colorant, protective agent, flame retardant, tackiness regulator, and mixtures thereof.

[0055] The specific amounts within said ranges usually depend on the final use of the film and on its composition. Using amounts above the higher limits will increase the price of the film without improving its properties any further.

[0056] The thickness of the film according to the invention can vary in a quite wide range. Thickness of the film may range from 0.1 to 10 mm, preferably from 0.2 to 4 mm, and still more preferably may be 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, 1.2 mm, 1.6 mm, 2.0 mm or 2.4 mm.

[0057] The film according to the invention presents high protective performance. Said performance is represented by the rebound resilience according to Test A which is less than 15%, preferably less than 10%.

[0058] Test A being as follows:

[0059] Rebound resilience is measured using a Schob pendulum according to standard DIN 53512 (April 2000), at 20 C. on a film having a thickness of 0.4 mm, said film being placed on the surface of a plastic test piece having a thickness of 12.5 mm and a rebound resilience of 24% (as measured using a Schob pendulum DIN 53512 (April 2000). The film according to the invention has a rebound resilience of less than 15%, preferably less than 10%.

[0060] Such a rebound resilience means that about 35%, preferentially about 55% of mechanical energy is absorbed by a film according to the invention having a thickness of 0.4 mm.

[0061] According to an advantageous embodiment, the film according to the invention is stretchable. In particular, the film according to the invention, presents an elongation at break of at least 10%, preferably at least 100% and even more preferably at least 300%, and can be as high as 1100%. Said elongation at break being measured according to DIN 53504, i.e. on a test piece having the size mentioned in DIN53504 and not directly on the film but presenting the same composition as the film.

[0062] The fact that the film is stretchable renders its use easier and allows an easy wrapping of the products to be protected and/or packaged and it allows a good fitting to the product without increasing its volume.

[0063] The film according to the invention may further present at least one of the following properties:

TABLE-US-00001 Tensile Strength 0.5 to 20 MPa, preferably 0.6 to 15 MPa (DIN 53504) Density (DIN 1306) 0.8/1.2 kg/dm.sup.3 Hardness (DIN 53505) 20-95 shore A 100% Young's modulus 0.3 to 10 MPa (DIN 53504) 300% Young's 0.8 to 13 MPa modulus (DIN 53504) Tan measured by DMA >0.5 on a range of 30 C., preferably on a range of 40 C. in case of efficiency against vibration

[0064] Said properties are not measured directly on the film but on test pieces having the dimensions mentioned in the respective standards.

[0065] Furthermore, the film can be self-extinguishing when set to fire, it can be transparent.

[0066] The film also presents a controlled tackiness.

[0067] In fact, according to the end use, it is possible to obtain a film with one or both surfaces presenting a tackiness which allows the application of a paper film which can be withdrawn, or presenting no tackiness.

[0068] Tan measured by DMA is representative of the protection against vibrations and impacts.

[0069] According to another aspect, the invention relates to a process for manufacturing a film as described above, comprising: [0070] providing a composition comprising at least one polymer and at least one plasticizer, said composition having a calculated Tg ranging between 35 C. and 40 C., preferably from 20 C. to 10 C.; [0071] optionally adding to said composition a filler, a cross-linking system, an additive and/or mixtures thereof; [0072] stretching said composition into a film in a calender at 20 to 120 C., preferably at 30 to 100 C., preferably 40 to 90 C.; [0073] optionally heating the film at a temperature ranging from 100 C. to 250 C., preferably from 110 C. to 200 C., and even more preferably from 150 C. to 170 C. if vulcanization is needed.

[0074] The step of stretching the film can be made on a two, three or four roll calender.

[0075] For vulcanised products the following step of heating and pressing of the film allows the vulcanization of the material, the duration of said step will depend on the composition of the film, on the type of vulcanization agents, on the vulcanization temperature and of the thickness of the film. It can be carried out on a Auma Machine. Typically, the duration of said step ranges from 1 min to 10 min, preferably from 2 min to 6 min, and even more preferably from 3 min to 4 min.

[0076] Providing the composition comprising at least one polymer and at least one plasticizer, said composition having a calculated Tg ranging between 35 C. and 40 C.; and optionally adding to said composition a filler, a vulcanization agent, an additive and/or mixtures thereof, may be carried out in one step or may be carried out in several steps of mixing and heating depending of the nature of the components, their compatibility. The mixture obtained at the end of these steps is called a compound.

[0077] Said compound is then stretched to obtain a film. A small amount of said compound can be reserved in order to carry some mechanical tests on it.

[0078] According to another embodiment, the process according to the invention can comprise a surface treatment on one or both surfaces of the film, in order to modify its surface properties, in particular to control its tackiness, its aspect and/or its odor. Halogenation, mechanical surface treatment, application of chemicals onto the surface (for example with waxes).

[0079] According to still another aspect, the invention relates to an element incorporating at least one film as defined above or as prepared according to the method described above.

[0080] Such an element can be a multilayer film, at least one of its layer being a film according to the invention. Said multilayer film can be obtained by co-extruding or by laminating different films on each other. The element can be a packaging element (cardboard, moulded polymer, etc.) which is coated by a film according to the invention.

[0081] Due to its high protection performance, the film according to the invention and/or the element incorporating said film can be used as wrapping film, protection packaging for transportation companies, removal companies, etc. It is specifically adapted for products which are very sensitive to impacts and/or vibrations, such as dishes, decorative objects, electronic devices, printed circuit boards, etc.

[0082] Thanks to the film or element incorporating the film according to the invention, packaging is easy and simple, is not voluminous and confers a high protection.

[0083] The film according to the invention and/or the element incorporating said film can also be used as a coating film applied on a device or part of a device which is submitted to vibrations. It can also be wrapped around the grip part of sport devices (for example rackets) or machines (for example air hammer), in order to limit the vibrations transmitted to the person who holds this grip part.

[0084] The present invention is described in further details in the below examples, which are only illustrative and are not intended to limit the scope of the invention.

EXAMPLES

[0085] The following materials are used in the examples:

Norsorex: polynorbornene
HNA oil: naphthenic oil
Silica MFIL-200: marketed by Konimpex
Resin C9: Aromatic resin marketed by KonimpeX Kaolin Diamond RHO marketed under the trademark Polwhite
Naftonox: antioxidant marketed by Rubber Dispersion chemical
DeovulkEG3: vulcanization accelerator agent marketed by King Industrie
Chlorbutyl 1240: chlorinated isobutylene-isoprene copolymer marketed by Lanxess
Rubatch 00EE55AJ: Mixture of 45.45% carbon black and 34.55% Styrene Butyl Rubber (Flavex 595)
MTBS Vulkacit DM-MG: di(benzothiazol-2-yl)disulphide
TMTD: Tetramethyl Thiuram Disulfide marketed by Konimpex
NBR: butadiene acrylonitrile marketed under the trademark Kumbo KNB 40M by Ulsan Synthetic Rubber Plant
PVC: polyvinylchloride marketed under the trademark Solvic by Solvay
EVA: Ethylene vinyl acetate marketed under the trademark LEVAPRENE 900 from LanxessA-C by Allied Signal
Eastman 168: Di-Ethylhexyl Ester marketed by Eastman with reference Eastman 168

[0086] In the examples, room temperature was about 20 C.+/2 C.

Example 1

Composition

[0087]

TABLE-US-00002 Weight Coumpound percentage Norsorex 22.7% HNA oil 45.5% Silica MFIL-200 8.9% Kaolin Diamond RHO 6.8% Resine C9 11.4% ZnO 1.0% Acide starique 0.2% Naftonox 0.4% (antioxidant) Sulfur 0.9% Deovulk EG3 2.3% (accelerator)

[0088] With said composition, a compound is prepared by mixing the different components, a part of it is vulcanized at a temperature of 150 C. during 10-12 minutes in a mold for forming sheets in which the test pieces are cutted according to various test standards. Properties are measured on said test pieces. The results of the measured properties are summarized in the following table:

TABLE-US-00003 Property Value Density (DIN 1306) 1.10 kg/dm.sup.3 Hardness (DIN 53505) 25 shoreA 100% Young's Modulus 0.68 MPa (DIN53504) 300% Young's Modulus 2.73 MPa (DIN53504) Tensile Strength 8.09 MPa (DIN53504) Rebound resilience 3% (DIN 53512) Elongation at Break 603% (DIN 53504)

[0089] The rest of the compound becomes plastified in a mill and then calendered to the desired thickness, using a 3 roll-calender. This pre-heated and pre-formed film becomes vulcanized at 160 C. during 4 minutes in order to obtain films presenting the following thicknesses: 0.4 mm, 0.8 mm, 1.2 mm, 1.6 mm, 2.0 mm, 2.4 mm, 2.8 mm and 3.2 mm.

[0090] Properties of the obtained films are given in the following table:

TABLE-US-00004 Rebound resilience according to Test A Room Thickness 20 C. 0 temp. 40 C. Tg 0 mm 24 Tg = 5 C. at 0.4 mm 12 6 10 8 2 Hz 0.8 mm 4.66 Tan > 0.5 1.2 mm 2.33 between 20 C. 1.6 mm 2 to 20 C. at 2 Hz 2.0 .4 mm 1.8 2 mm 2 2.8 mm 3 3.2 mm 2.6
Tan is measured from 60 C. to 90 C. The results are presented in FIG. 1. It results from said figure that tan is more than 0.5 on a wide range of temperatures from 20 C. to 20 C. at 2 Hz.

Example 2

Composition

[0091]

TABLE-US-00005 Compound percentage Chlorobutylrubber 72% (chlorbutyl 1240) Rubatch 00EE55AJ 2.2% Silica 15.6% Stearic acid 3.6% ZnO 3.6% MBTS/vulkacit DM-MG 2.1% TMTD 0.7%

[0092] With said composition, a compound is prepared by mixing the different components, a part of it is vulcanized at a temperature of 150 C. during 10-12 minutes in a mold for test pieces. From said vulcanized test sheet test pieces are cutted, following various test standards. The results of the measured properties are summarized in the following table:

TABLE-US-00006 Properties Value Density (DIN 1306) 0.90 kg/dm.sup.3 Hardness (DIN 53505) 25 shoreA 100% Young's Modulus 0.39 MPa (DIN53504) 300% Young's Modulus 0.81 MPa (DIN53504) Tensile Strength 3.28 MPa (DIN53504) Rebound resilience 3% (DIN 53512) Elongation at Break 1015% (DIN 53504)

[0093] The rest of the compound becomes plastified in a mill and then calendered to the desired thickness, using a 3 roll-calender. This pre-heated and pre-formed film becomes vulcanized at 160 C. during 4 minutes in order to obtain films presenting the following thicknesses: 0.4 mm, 0.8 mm, 1.2 mm, 1.6 mm, 2.0 mm, 2.4 mm, 2.8 mm and 3.2 mm.

[0094] Properties of the obtained films are given in the following table:

TABLE-US-00007 Rebound resilience according to Test A Tg/tan max Room range with Thickness 20 C. 0 C. temp. 40 C. tan > 0.5 0 mm 24 Tg = 30 C. at 0.4 mm 4 2 3 4 2 Hz 0.8 mm 1 Tan > 0.5 1.2 mm 1 between 40 C. 1.6 mm <1 to 0 C. at 2 Hz 2.0 mm <1
Tan is measured from 60 C. to 90 C. The results are presented in FIG. 2. It results from said figure that tan is more than 0.5 on a wide range of temperatures from 40 C. to 0 C. at 2 Hz.

Example 3

Composition

[0095]

TABLE-US-00008 Compound percentage NBR 12.7% PVC 21.9% EVA 1.7% Eastman 168 plasticizer 1.7% Norsorex 13.0% HNA oil 25.9% Silica MIFL 200 5.1% Kaolin diamond RHO 3.9% Resin C9 6.5% ZnO 0.6% Stearic acid 0.1% Naftonox (antioxidant) 0.2% Woskop 4.8% Sulfur 0.5% Deovulk (accelerator) 1.3%

[0096] With said composition, a compound is prepared by mixing the different components, a part of it is vulcanized at a temperature of 150 C. during 10-12 minutes in a mold for test pieces. From said vulcanized test sheet test pieces are cutted, following various test standards. The results of the measured properties are summarized in the following table:

TABLE-US-00009 Property Value Density (DIN 1306) 1.08 kg/dm.sup.3 Hardness (DIN 53505) 67 shoreA 100% Young's Modulus 2.38 MPa (DIN53504) 300% Young's Modulus 3.87 MPa (DIN53504) Tensile Strength 4.11 MPa (DIN53504) Color Brawn Rebound resilience 3% (DIN 53512) Elongation at Break 335% (DIN 53504)

[0097] The rest of the compound becomes plastified in a mill and then calendered to the desired thickness using a 3 roll-calender. This pre-heated and pre-formed film becomes vulcanized at 160 C. during 4 minutes in order to obtain films presenting the following thicknesses: 0.4 mm, 0.8 mm, 1.2 mm, 1.6 mm, 2.0 mm, 2.4 mm, 2.8 mm and 3.2 mm.

[0098] Properties of films presenting said different thicknesses are given in the following table:

TABLE-US-00010 Rebound resilience according to Test A Tg/tan max Room range with Thickness 20 C. 0 C. temp. 40 C. tan > 0.5 0 mm 24 Tg = 7 C. and 0.4 mm 7 8 2 8 42 C. C. at 0.8 mm <1 2 Hz 1.2 mm <1 1.6 mm <1 2.0 mm <1
Tan is measured from 60 C. to 90 C. The results are presented in FIG. 3. It results from said figure that tan is more than 0.5 on a wide range of temperatures from 20 C. to 15 C. at 2 Hz.

Example 4

Composition:

[0099]

TABLE-US-00011 Compound percentage NBR (Kumho KNB 40M) 78.0% PVC 19.0% EVA 1.5% Eastman 168 plasticizer 1.5%

[0100] The components of said composition are mixed on a 2 screw intermixer to obtain a plast compound which is extruded and feeded in a heating calender system between 90 to 100 C. to obtain a sheet which is cooled and de-stretched, and then cutted in test pieces in accordance to various test standards. The properties are measured on the cutted test pieces. The results of the measured properties are summarized in the following table:

TABLE-US-00012 Property Value Density (DIN 1306) 1.00 kg/dm.sup.3 Hardness (DIN 53505) 45 shoreA 100% Young's Modulus (DIN53504) 300% Young's Modulus (DIN53504) Tensile Strength 0.73 MPa (DIN53504) Rebound resilience 5% (DIN 53512) Elongation at Break 93% (DIN 53504)

[0101] The rest of the master batch is stretched on 3-roll Calender in order to obtain films presenting the following thicknesses: 0.4 mm, 0.8 mm, 1.2 mm, 1.6 mm, 2.0 mm, 2.4 mm, 2.8 mm and 3.2 mm. Properties of films presenting said different thicknesses are given in the following table:

TABLE-US-00013 Rebound resilience according to Test A Tg/tan max Room range with Thickness 20 C. 0 C. temperature 40 C. tan > 0.5 0 mm 24 Tg = 4 C. at 0.4 mm 4 4 2 6 2 Hz 0.8 mm <1 Tan > 0.5 1.2 mm <1 between 15 C. 1.6 mm <1 and 15 C. 2.0 mm <1

[0102] Tan is measured from 60 C. to 90 C. The results are presented in FIG. 4. It results from said figure that tan is more than 0.5 on a wide range of temperatures from 15 C. to 15 C. at 2 Hz.