Vulcanization-activating composition, method for producing same and use thereof

Abstract

The present invention relates to a method for producing a vulcanization-activating composition, the method comprising at least one step of mixing at least 5% by weight and at most 75% by weight of particles of an oxygen-bearing zinc compound, and at least 1% by weight and at most 75% by weight of at least one plant oil or of at least one plant oil derivative, thereby forming the composition (A); wherein said plant oil or plant oil derivative comprises, relative to the total weight of said plant oil or plant oil derivative: at least 8% by weight of at least one fatty acid residue, said fatty acid residue comprising at least two unsaturations.

Description

[0001] “VULCANIZATION ACTIVATOR COMPOSITION, ITS PREPARATION PROCESS AND ITS USE”

[0002] FIELD OF THE INVENTION

[0003] The present invention lies in the field of processes for preparing a vulcanization activator composition based on vegetable oil or derivative(s) of a vegetable oil.

[0004] STATE OF THE ART

[0005] Vulcanization is a crosslinking reaction that occurs when a vulcanizable polymer is placed in the presence of a vulcanizing agent (usually sulfur) and thermal energy. The latter is necessary to establish chemical bonds between the vulcanizing agent and the reactive sites of the polymer's molecular chains, thus forming a three-dimensional network.

[0006] Once the polymer is vulcanized, it has specific mechanical and elastic properties suitable for use in various fields of application, for example in tires.

[0007] In order to activate the vulcanization reaction between the polymer and the vulcanizing agent, it is known to use a vulcanization activator such as a divalent metal oxygen compound, the most commonly used of which is zinc oxide, ZnO.

[0008] Vulcanization activator compositions are already known to those skilled in the art. EP 3896129 A1 may be cited, which discloses a composition comprising from 20 to 80% by weight of at least one vulcanization activator, from 10 to 40% by weight of at least one wax chosen from the group consisting of paraffin-based waxes, microcrystalline waxes, polyolefin waxes, Fischer-Tropsch waxes, oxidized Fischer-Tropsch waxes, their derivatives and their mixtures, from 10 to 40% by weight of at least one inorganic filler or carbon black.

[0009] When these compositions are used in a vulcanization process, such as in the vulcanization of rubber, the ZnO and the other compounds included in the activator composition will be found at least partly (or totally) inside the vulcanized rubber. Unfortunately, it is known that the ZnO can then migrate out of the rubber and contaminate the environment. This is the case, for example, if the vulcanized rubber comes into prolonged contact with water. It has been observed that at least part of the ZnO can migrate out of the rubber and contaminate the water directly in contact with it. However, it is known that ZnO is ecotoxic. It therefore becomes necessary to develop vulcanization activator compositions that can reduce the amount of ZnO released into the environment by the vulcanized rubber or at least release only a small amount of ZnO.

[0010] Additionally, commonly used waxes such as paraffin waxes, microcrystalline waxes, polyolefin waxes and Fischer-Tropsch waxes are synthetic waxes. However, the industry is generally seeking to reduce the environmental footprint of its production processes. Therefore, there is a need to reduce the use of synthetic materials in vulcanization activator compositions.

[0011] SUMMARY OF THE INVENTION

[0012] The inventors surprisingly found that the composition according to the invention made it possible, among other things, to solve the problems identified above.

[0013] The present invention relates to a process for preparing a vulcanization activator composition [hereinafter, composition (A)], said process comprising at least one mixing step:

[0014] • at least 5% by weight and at most 95% by weight, preferably at least 5% by weight and at most 75% by weight of particles of an oxygenated zinc compound [hereinafter, compound (OZ)], and • at least 1% by weight and at most 75% by weight of at least one vegetable oil or at least one derivative of a vegetable oil, thus forming composition (A), the % by weight being based on the total weight of said composition (A); wherein said vegetable oil or the derivative of a vegetable oil comprises based on the total weight of said vegetable oil or the derivative of a vegetable oil: at least 8% by weight of at least one fatty acid residue; said fatty acid residue comprising at least two unsaturations.

[0015] The present invention also relates to a vulcanization activator composition obtained by the above process.

[0016] The present invention also relates to the use of a vulcanization activator composition obtained by the above process in a vulcanization process.

[0017] DETAILED DESCRIPTION

[0018] According to the present invention, the term "comprising" is inclusive and open and does not exclude the addition of elements which are not listed, compositions or process steps.

[0019] In the context of the present invention, if it is stipulated that an element or component is selected from a list of recited elements or components, it is to be understood that the element or component may also be any of the individual elements or components recited in said list, or may also be selected from a group consisting of two or more of the elements or components explicitly listed.

[0020] Composition (A)

[0021] As explained above, the present invention relates to an activator composition [composition (A)] for use in a vulcanization process.

[0022] Vulcanization processes are known to those skilled in the art. In general, a vulcanization reaction is a chemical crosslinking reaction occurring when a vulcanizable polymer (such as natural rubber) is brought into contact with a vulcanizing agent (usually sulfur) and thermal energy.

[0023] Preferably, said composition (A) is suitable for use in a process for vulcanizing a vulcanizable composition [composition (C)] comprising a polymer (V) when less than 10 parts by weight, more preferably less than 8 parts by weight, even more preferably less than 6 parts by weight of said composition (A) are included in the composition (C) relative to 100 parts by weight of the polymer (V).

[0024] The said mixture

[0025] Said method according to the invention comprises at least one mixing step:

[0026] • at least 5% by weight and at most 95% by weight, preferably at least 5% by weight and more than 75% by weight of particles of an oxygenated zinc compound [hereinafter, compound (OZ)], and

[0027] • at least 1% by weight and at most 75% by weight of at least one vegetable oil or at least one derivative of a vegetable oil, thus forming composition (A), based on the total weight of said composition (A).

[0028] Said mixing may be carried out by any means known to those skilled in the art for producing vulcanization activator compositions. In particular, said mixing may for example be carried out in a mixer, kneader, or any other machine for mixing said compound (OZ) and the vegetable oil or the derivative of a vegetable oil.

[0029] Preferably, the mixing is carried out at a temperature and for a duration which make it possible to prevent a significant part of the compound (OZ) and the vegetable oil or the derivative of a vegetable oil from reacting or degrading while allowing a homogeneous mixture of said compound (OZ) and the vegetable oil or said derivative of a vegetable oil to be obtained. Said temperature and said duration of mixing prevent, for example, a significant part of the unsaturations of said vegetable oil or the derivative of a vegetable oil from reacting or degrading.

[0030] Preferably, the mixture is carried out at a temperature of at most 100°C, more preferably at most 80°C, even more preferably at most 70°C, even more preferably at most 60°C, even more preferably at most 50°C, even more preferably at most 40°C. This has the effect of reducing or avoiding reactions between the natural oil and said compound (OZ) such as the formation of complexes between zinc and fatty acids or of avoiding degradation reactions of said vegetable oil or said derivative of a vegetable oil.

[0031] The mixture can be carried out at a temperature preferably of at least 10°C, more preferably at least 15°C, more preferably at least 17°C, more preferably at least 20°C.

[0032] In a preferred embodiment, said mixture is carried out at a temperature of at least 10°C and at most 40°C, more preferably at least 15°C and at most 40°C, more preferably at least 17°C and at most 40°C, more preferably at least 20°C and at most 40°C.

[0033] Preferably, said mixing is carried out for at most 30 minutes, or at most 20 minutes, or at most 10 minutes, or at most 5 minutes, or at most 1 minute or at most 30 seconds.

[0034] Preferably, during said mixing, the temperature is controlled by at least one thermocouple.

[0035] Depending on the amount of said compound (OZ) and the vegetable oil or the derivative of a vegetable oil, said compound (A) may be a powdery composition of particles of compound (OZ) at least partially coated with vegetable oil or the derivative of a vegetable oil or said composition (A) may be a pasty or liquid composition. In a preferred embodiment, said composition (A) is a powdery composition of particles of compound OZ at least partially coated, said method comprising at least one mixing step:

[0036] • at least 20% by weight and at most 60% by weight of particles of a compound (OZ), and

[0037] • at least 1% by weight and at most 35% by weight of at least one vegetable oil or at least one derivative of a vegetable oil, thus forming composition (A), based on the total weight of said composition (A).

[0038] In this embodiment, said composition (A) has a D50 of at least 1 pm, preferably at least 2 pm, more preferably at least 3 pm. Preferably, said composition (A) has a D50 of at most 20 pm, more preferably at most 15 pm.

[0039] In this embodiment, said composition (A) preferably has a D50 of at least 1 pm and at most 20 pm, more preferably of at least 2 pm and at most 15 pm.

[0040] In a preferred version of this embodiment, at most 70% by weight, preferably at most 68% by weight of said particles of a compound (OZ), based on the total weight of said composition (A), are mixed in the mixing step.

[0041] Preferably, at least 25% by weight, more preferably at least 30% by weight, of said at least one vegetable oil or said at least one derivative of a vegetable oil, based on the total weight of said composition (A), is mixed in the mixing step.

[0042] In another preferred embodiment, said composition (A) is a pasty or liquid composition, said method comprising at least one mixing step:

[0043] • at least 20% by weight and at most 60% by weight of particles of a compound (OZ), and • at least 15% by weight and at most 75% by weight of at least one vegetable oil or at least one derivative of a vegetable oil, thus forming composition (A), based on the total weight of said composition (A).

[0044] In this embodiment, at most 50% by weight, preferably at most 40% by weight of particles of a compound (OZ), based on the total weight of said composition (A), are mixed in the mixing step.

[0045] In this same embodiment, preferably at most 65% by weight, more preferably at most 55% by weight, even more preferably at most 45% by weight, even more preferably at most 40% by weight of said at least one vegetable oil or said at least one derivative of a vegetable oil, based on the total weight of said composition (A), are mixed in the mixing step.

[0046] In this same embodiment, preferably at least 20% by weight, more preferably at least 25% by weight of said at least one vegetable oil or said at least one derivative of a vegetable oil, based on the total weight of said composition (A), are mixed in the mixing step.

[0047] The compound (OZ)

[0048] In the context of the present invention, "zinc oxygen compound" may be defined as a compound comprising a zinc atom and an oxygen atom. In particular, said compound (OZ) is a vulcanization activator. In particular, said zinc oxygen compound may be selected from the group consisting of zinc oxide, zinc hydroxide, zinc carbonate, zinc hydroxycarbonate and mixtures thereof or derivatives thereof, preferably the zinc oxygen compound is zinc oxide (ZnO).

[0049] Preferably, said method comprises mixing at least 10% by weight of said compound (OZ), more preferably at least 12% by weight, more preferably at least 15% by weight, more preferably at least 20% by weight, more preferably at least 25% by weight, more preferably at least 30% by weight, more preferably at least 40% by weight, more preferably at least 50% by weight, more preferably at least 60% by weight of said compound (OZ) based on the total weight of said composition (A).

[0050] Preferably, said method comprises mixing at most 70% by weight of said compound (OZ), more preferably at most 65% by weight, more preferably at most 55% by weight, more preferably at most 50% by weight, more preferably at most 45% by weight, more preferably at most 40% by weight, more preferably at most 35% by weight of said compound (OZ) based on the total weight of said composition (A).

[0051] In a preferred embodiment, the mixture of at least 10% by weight and at most 70% by weight, preferably at least 12% by weight and at most 65% by weight, more preferably at least 15% by weight and at most 60% by weight, more preferably at least 15% by weight and at most 55% by weight, more preferably at least 15% by weight and at most 50% by weight of said compound (OZ) based on the total weight of said composition (A).

[0052] Preferably, said compound (OZ) has a D50 of at least 100 nm, more preferably at least 200 nm, even more preferably at least 300 nm, even more preferably at least 400 nm, even more preferably at least 500 nm, even more preferably at least 600 nm, even more preferably at least 700 nm, even more preferably at least 800 nm, even more preferably at least 1 pm, even more preferably at least 2 pm.

[0053] If desired, said compound (OZ) may have a D50 of at most 500 pm, or at most 100 pm, or at most 20 pm or at most 15 pm. In a preferred embodiment, said compound (OZ) has a D50 of at least 100 nm and at most 500 pm, preferably at least 300 nm and at most 100 pm, more preferably at least 500 nm and at most 20 pm, even more preferably at least 1 pm and at most 20 pm.

[0054] In the context of the present invention, the notation Dx represents a diameter, expressed in pm, with respect to which X% by volume of the total volume of the measured particles is composed of smaller particles. In the context of the present invention, all D50 particle size measurements are laser particle size measurements carried out in water.

[0055] In the context of the present invention, all BET specific surface area values ​​of any products such as for example coated particles or any given compound are measured by adsorption manometry of a mixture of nitrogen and helium gas and calculated according to the BET method, after degassing under vacuum at 50°C for at least 1 hour.

[0056] If desired, said OZ compound may have a BET surface area of ​​at least 1 m 2 / g, preferably at least 2 m 2 / g.

[0057] If desired, said OZ compound may have a BET surface area of ​​at most 100 m2 / g, preferably not more than 60 m 2 / g.

[0058] In a preferred embodiment, said OZ compound has a BET surface area of ​​at least 1 m 2 / g and at most 100 m 2 / g, preferably at least 2 m 2 / g and at most 60 m 2 / g.

[0059] If desired, said OZ compound has a D50 measured by laser particle size analysis in methanol, after a 3-minute ultrasonic treatment of at least 0.25 pm, preferably at least 3 pm, more preferably at least 5 pm.

[0060] If desired, said OZ compound has a D50 measured by laser granulometry in water, after an ultrasonic treatment of 3 minutes of at most 5000 pm, preferably at most 4000 pm, more preferably at most 3000 pm; at most 100 pm, at most 50 pm, at most 10 pm; at most 7 pm.

[0061] In one embodiment, said OZ compound has a D50 measured by laser granulometry in methanol, after a 3-minute ultrasonic treatment of at least 0.25 pm and at most 4000 pm, at least 3 pm and at most 3000 pm, more preferably at least 5 pm and at most 100 pm, even more preferably at least 5 pm and at most 50 pm, even more preferably at least 5 pm and at most 10 pm, even more preferably at least 5 pm and at most 7 pm.

[0062] The said natural oil

[0063] In the context of the present invention, the term "vegetable oil" takes its usual meaning known to those skilled in the art. In general, a vegetable oil is an oil obtained or derived, preferably extracted from a plant or a part of a plant such as seeds. Vegetable oils that can be used in the context of the present invention include, for example (but are not limited to): linseed oil, walnut oil, sunflower oil, corn oil, avocado oil, hemp oil, grapeseed oil, olive oil, peanut oil, rice oil, sesame oil, soybean oil, rapeseed oil, safflower oil, wheat germ oil and mixtures thereof.

[0064] In the context of the present invention, the term "vegetable oil derivative" covers, for example, at least partially polymerized vegetable oils, partially polymerized oils, dehydrogenated vegetable oils, vegetable oils that have undergone an aging treatment, a thermal or chemical treatment and mixtures thereof. Therefore, a vegetable oil derivative may include oils of the type (in English) "stand oil", "raw oil" (crue) and "boiled oil" (cooked).

[0065] Examples of vegetable oil derivatives include (but are not limited to): aged linseed oil, partially polymerized linseed oil, cooked linseed oil, dehydrogenated palm oil, and mixtures thereof. Examples of a derivative of a vegetable oil include derivatives of linseed oil, walnut oil, sunflower oil, corn oil, avocado oil, hemp oil, grapeseed oil, olive oil, peanut oil, rice oil, sesame oil, soybean oil, rapeseed oil, safflower oil, wheat germ oil, palm oil, and mixtures thereof.

[0066] Using a vegetable oil or a derivative of a vegetable oil is advantageous because it is a bio-sourced material.

[0067] According to the invention, said vegetable oil or the derivative of a vegetable oil comprises, based on the total weight of said vegetable oil or the derivative of a vegetable oil: at least 8% by weight of at least one fatty acid residue.

[0068] In the context of the present invention, the term "fatty acid residue" takes its usual meaning known to those skilled in the art. For example, the fatty acid residue may be part of a fat and be at least partly in the form of a triglyceride, a diglyceride and / or a monoglyceride. The fatty acid residue may also be at least partly in the form of a free fatty acid, i.e. not in the form of a glyceride. The free fatty acid may be in protonated or at least partially deprotonated form.

[0069] The fatty acid residue can be linear or branched.

[0070] Fatty acid residues that may be used include (but are not limited to): linoleic acid, α-linolenic acid, γ-linolenic acid, dihomo-γ-linolenic acid, arachidonic acid, eicosapentaenoic acid and docosahexaenoic acid residues.

[0071] According to the invention, said fatty acid residue comprises at least 2 unsaturations, preferably at least 3 unsaturations.

[0072] The inventors have surprisingly noticed that the use of composition (A) according to the invention in a vulcanization process makes it possible to reduce or in certain cases to avoid the release of zinc from the compound (OZ) (or zinc) outside the vulcanized polymer.

[0073] Without wishing to be bound by a theory, the inventors believe that at least some of the unsaturations included in said vegetable oil or in said vegetable oil derivative would react during vulcanization. Consequently, at least some of the fatty acid residues having unsaturations would be incorporated by crosslinking into the vulcanized polymer. This incorporation is greater or more likely when the fatty acid residue carries at least two unsaturations. In addition, it would appear that after vulcanization, some of the fatty acid residues carrying unsaturations are no longer in the form of glycerides but in the form of fatty acid whose carboxylic acid functions (in the form of carboxylates) at least partially complex the zinc. The complexation of zinc by fatty acid residues trapped in the matrix of the vulcanized polymer would make it possible to retain at least some or all of the zinc of the compound (OZ).

[0074] Moreover, it surprisingly appeared that the properties of the vulcanized polymers were not significantly impacted by the presence of vegetable oil.

[0075] Furthermore, the inventors noticed that the compositions in which the vegetable oil was present in the composition according to the invention had an advantageously lower angle of slope than for compositions comprising only an OZ compound, which indicates that the composition flows smoothly.

[0076] The unsaturations of said fatty acid residue may be cis or trans.

[0077] Preferably, the unsaturations of said fatty acid residue are separated by at least one -CH2- function, more preferably by only one -CH2- function.

[0078] Preferably, said fatty acid residue is a C12-C30 residue, more preferably C14-C28, more preferably C14-C26, even more preferably C14-C24, more preferably C16-C24, more preferably C16-C22, more preferably C16-C20, even more preferably C18.

[0079] Preferably, said vegetable oil and / or said vegetable oil derivative comprises at least 15% by weight of said fatty acid residue, more preferably at least 20% by weight of said fatty acid residue, even more preferably at least 25% by weight of said fatty acid residue, more preferably at least 30% by weight of said fatty acid residue, more preferably at least 35% by weight of said fatty acid residue, even more preferably at least 40% by weight of said fatty acid residue, even more preferably at least 50% by weight of said fatty acid residue, based on the total weight of said vegetable oil or said vegetable oil derivative.

[0080] Preferably, said vegetable oil and / or said vegetable oil derivative comprises at most 80% by weight of said fatty acid residue, more preferably at most 75% by weight of said fatty acid residue, even more preferably at most 70% by weight of said fatty acid residue, based on the total weight of said vegetable oil or said vegetable oil derivative.

[0081] In a preferred embodiment, said vegetable oil and / or said vegetable oil derivative comprises at least 15% by weight and at most 80% by weight of said fatty acid residue, more preferably at least 20% by weight and at most 80% by weight of said fatty acid residue, even more preferably at least 25% by weight and at most 75% by weight of said fatty acid residue, more preferably at least 30% by weight and at most 70% by weight of said fatty acid residue, more preferably at least 35% by weight and at most 70% by weight of said fatty acid residue, even more preferably at least 40% by weight and at most 70% by weight of said fatty acid residue, even more preferably at least 50% by weight and at most 70% by weight of said fatty acid residue, based on the total weight of said vegetable oil or said vegetable oil derivative.In a preferred embodiment, said vegetable oil and / or said vegetable oil derivative comprises a fatty acid residue (A) comprising two unsaturations and a fatty acid residue (B) comprising at least three unsaturations. The fatty acid residue (A) may be a linoleic acid residue. The fatty acid residue (B) may be an α-linolenic acid, γ-linolenic acid, dihomo-γ-linolenic acid, arachidonic acid, eicosapentaenoic acid or docosahexaenoic acid residue.

[0082] Preferably, the unsaturations of said fatty acid residues (A) and (B) are separated by at least one -CH2- function, more preferably by only one -CH2- function.

[0083] Preferably, each fatty acid residue is a C12-C30 residue, more preferably C14-C28, more preferably C14-C26, even more preferably C14-C24, more preferably C16-C24, more preferably C16-C22, more preferably C16-C20, even more preferably C18.

[0084] Preferably, said vegetable oil and / or said vegetable oil derivative comprises at least 8% by weight, more preferably at least 10% by weight of said fatty acid residue (A), based on the total weight of said vegetable oil or said vegetable oil derivative.

[0085] Preferably, said vegetable oil and / or said vegetable oil derivative comprises at most 30% by weight, more preferably at most 25% by weight, even more preferably at most 20% by weight of said fatty acid residue (A), based on the total weight of said vegetable oil or said vegetable oil derivative.

[0086] In a preferred embodiment, said vegetable oil and / or said vegetable oil derivative comprises at least 8% by weight and at most 30% by weight, more preferably at least 10% by weight and at most 25% by weight, even more preferably at least 10% by weight and at most 20% by weight of said fatty acid residue (A), based on the total weight of said vegetable oil or said vegetable oil derivative.

[0087] Preferably, said vegetable oil and / or said vegetable oil derivative comprises at least 30% by weight, more preferably at least 35% by weight, even more preferably at least 40% by weight of said fatty acid residue (B), based on the total weight of said vegetable oil or said vegetable oil derivative.

[0088] Preferably, said vegetable oil and / or said vegetable oil derivative comprises at most 75% by weight, more preferably at most 70% by weight, even more preferably at most 65% by weight of said fatty acid residue (B), based on the total weight of said vegetable oil or said vegetable oil derivative.

[0089] In a preferred embodiment, said vegetable oil and / or said vegetable oil derivative comprises at least 30% by weight and at most 75% by weight, more preferably at least 35% by weight and at most 70% by weight, even more preferably at least 10% by weight and at most 65% by weight of said fatty acid residue (B), based on the total weight of said vegetable oil or said vegetable oil derivative.

[0090] In a preferred embodiment, said vegetable oil and / or said vegetable oil derivative comprises at least 10% by weight and at most 20% by weight of said fatty acid residue (A) and at least 10% by weight and at most 65% by weight of said fatty acid residue (B), based on the total weight of said vegetable oil or said vegetable oil derivative; said fatty acid residue (A) being a C16-C22 residue comprising at least two unsaturations separated by a -CH2- group; said fatty acid residue (B) being a C16-C22 residue comprising at least three unsaturations separated by a -CH2- group.

[0091] In an even more preferred embodiment, said vegetable oil is linseed oil, said linseed oil comprising at least 10% by weight and at most 20% by weight of said fatty acid residue (A) and at least 10% by weight and at most 65% by weight of said fatty acid residue (B); said fatty acid (A) being linoleic acid and said fatty acid (B) being α-linolenic acid.

[0092] Preferably, said vegetable oil and / or said derivative of a vegetable oil comprises at least one fatty acid residue comprising unsaturation.

[0093] Preferably, said vegetable oil and / or said derivative of a vegetable oil comprises at least 5% by weight, more preferably at least 10% by weight, even more preferably at least 12% by weight of said fatty acid residue comprising unsaturation, based on the total weight of said vegetable oil or said derivative of a vegetable oil.

[0094] Preferably, said vegetable oil and / or said derivative of a vegetable oil comprises at most 35% by weight, more preferably at most 30% by weight, even more preferably at most 20% by weight of said fatty acid residue comprising unsaturation, based on the total weight of said vegetable oil or said derivative of a vegetable oil.

[0095] Preferably, said vegetable oil and / or said derivative of a vegetable oil comprises at least 5% by weight and at most 35% by weight, more preferably at least 10% by weight and at most 30% by weight, even more preferably at least 12% by weight and at most 20% by weight of said fatty acid residue comprising unsaturation, based on the total weight of said vegetable oil or said derivative of a vegetable oil.

[0096] Preferably, said fatty acid residue comprising unsaturation is an oleic acid residue.

[0097] Preferably, said vegetable oil and / or said derivative of a vegetable oil also comprises other saturated fatty acid residues, such as for example palmitic acid and stearic acid residues.

[0098] Preferably, said vegetable oil and / or said derivative of a vegetable oil has an iodine value measured according to ISO 3961 of at least 160, preferably at least 170, more preferably at least 175 grams of h per gram of said vegetable oil or said derivative of a vegetable oil.

[0099] Preferably, said vegetable oil and / or said derivative of a vegetable oil has an acid value measured according to ISO 660 of at most 1, more preferably at most 2, more preferably at most 4 mg of KOH per g of said vegetable oil or said derivative of a vegetable oil.

[0100] Preferably, said vegetable oil and / or said derivative of a vegetable oil has a viscosity measured at 37.8°C according to the ASTM D445 standard of at least 35 mPa.s, more preferably at least 40 mPa.s. Preferably, said vegetable oil and / or said derivative of a vegetable oil has a viscosity measured at 37.8°C according to the ASTM D445 standard of at most 65 mPa.s, more preferably at most 60 mPa.s, more preferably at most 55 mPa.s. In a preferred embodiment, said vegetable oil and / or said derivative of a vegetable oil has a viscosity measured at 37.8°C according to the ASTM D445 standard of at least 35 and at most 65 mPa.s, more preferably of at least 40 and at most 60 mPa.s, more preferably of at least 40 and at most 55 mPa.s.

[0101] Preferably, said vegetable oil and / or said derivative of a vegetable oil has a saponification value measured according to ISO 3657 of at most 200, more preferably at most 195 mg of KOH per g of said vegetable oil or said derivative of a vegetable oil. Preferably, said vegetable oil and / or said derivative of a vegetable oil has a saponification value measured according to ISO 3657 of at least 175, more preferably at least 170 mg of KOH per g of said vegetable oil or said derivative of a vegetable oil. Preferably, said vegetable oil and / or said derivative of a vegetable oil has a saponification value measured according to ISO 3657 of at least 175 and at most 200, more preferably at least 170 mg and at most 195 mg of KOH per g of said vegetable oil or said derivative of a vegetable oil. Magnesium oxide

[0102] Preferably, said mixing step further comprises mixing at least 0.1% by weight and at most 75% by weight of magnesium oxide, thereby forming composition (A), based on the total weight of said composition (A).

[0103] Therefore, preferably, said method according to the invention comprises at least one mixing step:

[0104] • at least 5% by weight and at most 75% by weight of particles of an oxygenated zinc compound [hereinafter, compound (OZ)], and

[0105] • at least 1% by weight and at most 75% by weight of at least one vegetable oil or at least one derivative of a vegetable oil,

[0106] • at least 0.1% by weight and at most 75% by weight of magnesium oxide, thus forming composition (A), based on the total weight of said composition (A).

[0107] Preferably, at least 0.5% by weight, more preferably at least 0.8% by weight, even more preferably at least 1% by weight of magnesium oxide are mixed in said mixing step.

[0108] If desired, at least 5% by weight or at least 10% by weight or at least 20% by weight or at least 30% by weight or at least 40% by weight of magnesium oxide is mixed in said mixing step.

[0109] Preferably, at most 75% by weight, more preferably at most 70% by weight, even more preferably at most 60% by weight, even more preferably at most 50% by weight, even more preferably at most 40% by weight, even more preferably at most 30% by weight, even more preferably at most 20% by weight, even more preferably at most 10% by weight of magnesium oxide are mixed in said mixing step. Preferably, at least 0.5% by weight and at most 7% by weight, more preferably at least 0.5% by weight and at most 5% by weight, even more preferably at least 1% by weight and at most 3% by weight of magnesium oxide are mixed in said mixing step.

[0110] Calcium carbonate

[0111] Preferably, said mixing step further comprises mixing at least 10% by weight and at most 80% by weight of at least one inorganic base thus forming composition (A), based on the total weight of said composition (A).

[0112] The inventors noticed that the compositions in which the inorganic base was present in the composition according to the invention had an advantageously low angle of repose which indicates that the composition flows smoothly.

[0113] Preferably, the composition according to the present invention has a slope angle of at most 42°, more preferably at most 40°, even more preferably at most 39°, even more preferably at most 38°, even more preferably at most 37°.

[0114] Therefore, preferably, said method according to the invention comprises at least one mixing step:

[0115] • at least 5% by weight and at most 75% by weight of particles of an oxygenated zinc compound [hereinafter, compound (OZ)], and

[0116] • at least 1% by weight and at most 75% by weight of at least one vegetable oil or at least one derivative of a vegetable oil,

[0117] • at least 10% by weight and at most 80% by weight of at least one inorganic base, thus forming composition (A), based on the total weight of said composition (A).

[0118] In a preferred embodiment, said method according to the invention comprises at least one step of mixing: • at least 5% by weight and at most 75% by weight of particles of an oxygenated zinc compound [hereinafter, compound (OZ)], and

[0119] • at least 1% by weight and at most 75% by weight of at least one vegetable oil or at least one derivative of a vegetable oil,

[0120] • at least 10% by weight and at most 80% by weight of at least one inorganic base,

[0121] • at least 0.1% by weight and at most 75% by weight of magnesium oxide, thus forming composition (A), based on the total weight of said composition (A).

[0122] If desired, said at least one inorganic base comprises at least one alkali or alkaline-earth cation M, preferably chosen from the group consisting of Li + , N / A + , K + , That 2+ , Mg 2+ and their combinations and at least one anion A, preferably chosen from the group consisting of O 2- , OH-, COa 2 ', HCOa' and their combinations.

[0123] Preferably, said at least one inorganic base has the formula [M]x[A] y in which M is an alkali or alkaline earth cation, preferably selected from the group consisting of Li + , N / A + , K + , That 2+ , Mg 2+ and combinations thereof and A is an anion, preferably selected from the group consisting of O2- OH-, COa 2 ', HCOa' and their combinations. The coefficients x and y can take the values ​​1 or 2 or a value between 1 and 2. The value of the coefficients x and y depends on the cation and the anion.

[0124] More preferably, said at least one inorganic base is chosen from the group consisting of LiOH, NaOH, KOH, Ca(OH)2, Mg(OH)2, MgO Ü2CO3, Na2CO3, K2CO3, CaCO3, CaO, MgCO3, LiHCO3, NaHCOs, KHCO3, Ca(HCO3)2, Mg(HCO3)2, MgO.CaO and their mixtures and / or combinations.

[0125] Preferably, said inorganic base is a carbonate. In the context of the present invention, the term "carbonate" also includes compounds comprising the anion CO3 2 than the HCOa' anion, the term therefore also includes hydrogen carbonates and hydroxy carbonates.

[0126] Said carbonate can for example be CaCOa, NaaCOa, MgCOa, AI2(CO3)3, NaHCOs.

[0127] Preferably, said carbonate is CaCOa.

[0128] Preferably, at least 13% by weight, more preferably at least 15% by weight, even more preferably at least 17% by weight of inorganic base are mixed in said mixing step.

[0129] Preferably, at most 75% by weight, more preferably at most 70% by weight, even more preferably at most 65% by weight of inorganic base are mixed in said mixing step.

[0130] Preferably, at least 13% by weight and at most 75% by weight, more preferably at least 15% by weight and at most 70% by weight, even more preferably at least 17% by weight and at most 65% by weight of inorganic base are mixed in said mixing step.

[0131] Other additives / fillers

[0132] If desired, said mixing step may comprise further mixing at least 10% by weight and at most 80% by weight of at least one filler thereby forming composition (A), based on the total weight of said composition (A).

[0133] In the context of the present invention, said filler (I) may be any filler that can be used in a vulcanization process. The term "filler" does not mean that the filler (I) is inert, indeed, the filler (I) may be a base for example. It is also possible that the filler (I) may also play a role or not in the vulcanization process.

[0134] Said filler (I) includes, but is not limited to: alumina, silica, hydroxides, silicates, and mixtures thereof. Silica may include, but is not limited to, silica fume or precipitated silica.

[0135] Use in a vulcanization process

[0136] As indicated above, the present invention also relates to a method for vulcanizing a vulcanizable composition [composition (C)] comprising, relative to the total weight of the composition (C), the steps of: providing said composition (C) comprising: at least one vulcanizable polymer [polymer (V)] with between 2 and 10 parts by weight of said composition (A) according to the invention relative to 100 parts by weight of said polymer (V) and between 0.2 to 15 parts by weight of at least one vulcanizing agent [agent (V)] relative to 100 parts by weight of said polymer (V) to form said composition (C).

[0137] Preferably, said composition (C) is heated to a temperature and duration sufficient to obtain a vulcanized composition.

[0138] According to the present invention the terms "vulcanizable composition" refer to a composition suitable for undergoing a vulcanization reaction as described above.

[0139] The mixture of at least one polymer (V) and said composition (A) may comprise other compounds, consequently said composition (C) may also comprise other compounds.

[0140] The step of heating said composition (C) can be carried out by means known to those skilled in the art, such as for example a heating press.

[0141] Preferably said composition (C) can be heated to a temperature of at least 120°C, preferably at least 140°C, preferably at least 150°C, more preferably at least 165°C. If desired, said composition (C) is heated to a temperature of at most 220°C, preferably at most 200°C, more preferably at most 180°C.

[0142] In a preferred embodiment, said composition (C) is heated to a temperature between 120°C and 220°C, more preferably between 160°C and 200°C, even more preferably between 165°C and 180°C.

[0143] The heating time of said composition (C) must be sufficient to obtain a vulcanized composition. A person skilled in the art can apply the heating times usually used in the state of the art.

[0144] Polymer (V)

[0145] The terms “vulcanizable polymer” [hereinafter, polymer (V)] refer to any type of polymer capable of undergoing a vulcanization reaction, i.e. capable of being chemically crosslinked during this reaction.

[0146] The polymer (V) according to the present invention preferably comprises at least one monomeric unit having at least one unsaturation. The latter then serves as an active site during crosslinking. Preferably, the polymer (V) comprises several unsaturations.

[0147] The polymer (V) may be, for example, a homopolymer, a copolymer or a terpolymer and may be obtained by Ziegler-Natta or metallocene type polymerization processes, without however being limited to the aforementioned polymerization processes.

[0148] Preferably, the polymer (V) may be an elastomer. For example, the polymer (V) includes, but is not limited to, natural rubbers, polyisoprene, styrene butadiene (SBR), polybutadiene, isoprene butadiene (IBR), styrene-isoprene butadiene (SIBR), ethylene propylene / ethylene propylene diene (EPDM), nitrile elastomers, propylene oxide polymers, star-branched butyl elastomers, halogenated star-branched butyl elastomers, brominated butyl rubber, chlorinated butyl rubber, crosslinked star-branched polyisobutylene rubber, brominated star-branched butyl rubber (polyisobutylene / isoprene copolymer), poly(isobutylene-co-alkylstyrene), preferably isobutylene / methylstyrene copolymers such as isobutylene / meta-bromomethylstyrene, isobutylene / bromomethylstyrene, isobutylene / chloromethylstyrene, isobutylene cyclopentadiene and isobutylene / chloromethylene.

[0149] Preferably, the polymer (V) comprises an ethylene repeating unit. Said polymer (V) preferably comprises at least 20% by weight, preferably at least 30% by weight, more preferably at least 40% by weight, even more preferably at least 50% by weight of said ethylene repeating unit relative to the total weight of said polymer (V). Said polymer (V) may preferably comprise at most 95% by weight, more preferably at most 90% by weight, even more preferably at most 85% by weight, even more preferably at most 80% by weight of said ethylene repeating unit relative to the total weight of said polymer (V).

[0150] In a preferred embodiment, said polymer (V) comprises between 20% and 95%, preferably between 30% and 90%, more preferably between 40% and 85%, even more preferably between 50% and 80% by weight of said ethylene repeating unit relative to the total weight of said polymer (V).

[0151] More preferably, said polymer (V) further comprises a diene repeating unit. Said diene repeating unit includes, for example, but is not limited to, isoprene, butadiene, ethylidene norbornene, dicyclopentadiene, vinyl norbornene and mixtures thereof.

[0152] Preferably, the polymer (V) comprises a diene repeating unit. Said polymer (V) preferably comprises at least 0.1% by weight, preferably at least 0.2% by weight, more preferably at least 0.3% by weight, even more preferably at least 0.4%, even more preferably at least 0.5% by weight of said diene repeating unit relative to the total weight of said polymer (V). Said polymer (V) may preferably comprise at most 25% by weight, more preferably at most 20% by weight, even more preferably at most 15% by weight, even more preferably at most 12% by weight of said diene repeating unit relative to the total weight of said polymer (V).

[0153] In a preferred embodiment, said polymer (V) comprises between 0.1% and 25%, preferably between 0.2% and 20%, more preferably between 0.3% and 15%, even more preferably between 0.5% and 12% by weight of said diene repeating unit relative to the total weight of said polymer (V).

[0154] In another particular embodiment, the polymer (V) is a terpolymer and comprises between 50% and 80% by weight of said ethylene repeating unit and between 0.1% and 25%, preferably between 0.2% and 20%, more preferably between 0.3% and 15%, even more preferably between 0.5% and 12% of said diene repeating unit relative to the total weight of said polymer (V), said diene repeating unit being chosen from the group consisting of ethylidene norbornene, dicyclopentadiene, vinyl norbornene and mixtures thereof.

[0155] In another alternative embodiment, it may be necessary for the polymer (V) to have a lower weight percentage of diene, in which case the polymer (V) comprises between 0.1% and 10%, preferably between 0.2% and 9%, more preferably between 0.3% and 8%, even more preferably between 0.5% and 7.5% by weight of said diene repeating unit relative to the total weight of said polymer (V). In this case, the polymer (V) further preferably comprises between 20% and 95%, more preferably between 30% and 90%, more preferably between 40% and 85%, even more preferably between 50% and 80% by weight of said ethylene repeating unit relative to the total weight of said polymer (V), said diene repeating unit being selected from the group consisting of ethylidene norbornene, dicyclopentadiene, vinyl norbornene and mixtures thereof.

[0156] In yet another alternative embodiment, it may be necessary for the polymer (V) to have a higher weight percentage of diene, in which case the polymer (V) comprises between 1% and 20%, preferably between 2.5% and 17%, more preferably between 5% and 15%, even more preferably between 7% and 12% by weight of said diene repeating unit relative to the total weight of said polymer (V).In this case, the polymer (V) further preferably comprises between 20% and 95%, more preferably between 30% and 90%, more preferably between 40% and 85%, even more preferably between 50% and 80%, even more preferably between 50% and 70%, even more preferably between 50% and 75%, even more preferably between 50% and 70%, even more preferably between 50% and 65% by weight of said ethylene repeating unit relative to the total weight of said polymer (V), said diene repeating unit being chosen from the group consisting of ethylidene norbornene, dicyclopentadiene, vinyl norbornene and mixtures thereof.

[0157] The polymer (V) may further comprise a propylene repeating unit.

[0158] The provision of said composition (C) comprising the mixture of at least one vulcanizable polymer [polymer (V)] with between 2 and 10 parts by weight of said composition (A) relative to 100 parts by weight of said polymer (V). Preferably, the provision of said composition (C) may comprise the mixture of at least one polymer (V) with preferably between 2 and 8 parts by weight, more preferably between 3 and 7 parts by weight, even more preferably between 4 and 6 parts by weight of said composition (A) relative to 100 parts by weight of said polymer (V). Additional component

[0159] Preferably, the step of providing said composition (C) may comprise a step of adding at least one additional component to said polymer (V). Said at least one additional component being chosen from the group consisting of diatomaceous earth, quartz, talc, glass filaments, graphite, carbon black, carbon nanotubes and mixtures thereof.

[0160] In a preferred embodiment, said at least one additional component is carbon black.

[0161] Oily phase

[0162] Preferably, the step of providing said composition (C) may comprise a step of adding an oily phase to said polymer (V).

[0163] The oily phase is liquid at room temperature. Preferably, the oily phase is liquid at a temperature of -20°C, preferably -10°C, preferably -5°C, more preferably 0°C, even more preferably 5°C, even more preferably 10°C, even more preferably at a temperature of 15°C.

[0164] If desired, the step of adding an oily phase to said polymer may be carried out before or after said step of adding at least one additional component. Alternatively, the step of adding an oily phase to said polymer may be carried out simultaneously or at least partly simultaneously with said step of adding at least one additional component.

[0165] Vulcanization accelerator

[0166] Preferably, the step of providing said composition (C) may further comprise adding a vulcanization accelerator [accelerator (V)].

[0167] Any accelerator (V) commonly used in vulcanization processes may be used. In general, the accelerator (V) is selected from compounds capable of interacting with the activator (V) so as to reduce the vulcanization time and / or temperature. Preferably, said accelerator is selected from the group consisting of amino aldehydes, guanidines, thiazoles, thiophosphates, sulfenamides, thioureas, thiurams, dithiocarbamates, xanthates and mixtures thereof.

[0168] Examples of amino aldehydes include, but are not limited to: hexamethylenetetramine, heptaldehyde-aniline condensation products, and mixtures thereof. Examples of guanidines include, but are not limited to: diphenyl guanidine, N,N'-diorthitolyl guanidine, and mixtures thereof.

[0169] Examples of thiazoles include, but are not limited to: 2-mercaptobenzothiazole, 2-2'-dithiobis(benzothiazole), zinc-2-mercaptobenzothiazole, and mixtures thereof. A thiophosphate may, for example, be zinc-O,O-di-N-phosphorodithioate. Sulfenamides include, but are not limited to: N-cyclohexyl-2-benzothiazole sulfenamide, N-tert-butyl-2-benzothiazole sulfenamide, 2-(4-morpholinothio)-benzothiazole, N,N'-dicyclohexyl-2-benzothiazole sulfenamide, and mixtures thereof. Thiourea compounds include, but are not limited to: ethylene thiourea, di-pentamethylene thiourea, dibutyl thiourea, and mixtures thereof. Thiurams include but are not limited to: tetramethylthiuram monosulfide, tetramethylthiuram disulfide, dipentamethylenethiuram tetrasulfide, tetrabenzylthiuram disulfide, and mixtures thereof.Dithiocarbamates include, but are not limited to: zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, zinc dibenzyldithiocarbamate, and mixtures thereof. Examples of xanthate include zinc isopropyl xanthate.

[0170] In a preferred embodiment, said accelerator (V) is selected from the group consisting of mercaptobenzothiazole, tetramethylthiuram disulfide, N-cyclohexyl-2-benzothiazole sulfenamide, zinc dibutyldithiocarbamate and mixtures thereof.

[0171] In a more preferred embodiment, said accelerator (V) is a mixture of mercaptobenzothiazole, tetramethylthiuram disulfide, N-cyclohexyl-2-benzothiazole sulfenamide, zinc dibutyldithiocarbamate.

[0172] Preferably, at least 0.2 parts by weight, more preferably at least 0.5 parts by weight, even more preferably at least 1 part by weight, even more preferably at least 1.5 parts by weight of said accelerator (V) may be added relative to 100 parts by weight of said polymer (V). If desired, at most 15 parts by weight, more preferably at most 12 parts by weight, even more preferably at most 10 parts by weight of said accelerator (V) may be added relative to 100 parts by weight of said polymer (V).

[0173] In one embodiment, between 0.2 and 15 parts by weight, preferably between 0.5 and 12 parts by weight, more preferably between 1 and 10 parts by weight, even more preferably between 1.5 and 10 parts by weight of said accelerator (V) may be added relative to 100 parts by weight of said polymer (V).

[0174] Agent (V)

[0175] According to the present invention, the agent (V) is an agent allowing the vulcanization of the polymer (V). Preferably, the agent (V) is adapted to react with at least one unsaturation of the polymer (V) so as to induce the crosslinking of the latter.

[0176] Examples of agent (V) include, but are not limited to: sulfur, polysulfides, sulfur monochloride, sulfur dichloride, tellurium, selenium, thiurams, disulfides such as quinonedioximes, organic peroxides, diisocyanates. Preferably, agent (V) is a sulfur compound, and more preferably comprising at least one disulfide bond (SS). More preferably, agent (V) is a sulfur compound selected from the group of sulfur, sulfur chlorides, polysulfides and mixtures thereof.

[0177] The inventors have demonstrated that to obtain a vulcanizable composition, the composition (C) must contain at least 0.2 parts by weight of an agent (V) relative to 100 parts by weight of said polymer (V). Preferably, said composition (C) contains at least 0.3 parts by weight, more preferably at least 0.5 parts by weight of said agent (V) relative to 100 parts by weight of said polymer (V).

[0178] The method according to the invention comprises a step of adding 0.2 to 15 parts by weight of at least one vulcanizing agent [agent (V)] relative to 100 parts by weight of said polymer (V) to form said composition (C).

[0179] In a preferred embodiment, the method according to the invention comprises a step of adding 0.2 parts by weight to 4 parts by weight, preferably 0.3 parts by weight to 3 parts by weight, more preferably 0.5 parts by weight to 3 parts by weight of said agent (V) relative to 100 parts by weight of said polymer (V).

[0180] Agent (V) is advantageously added in the form of a powder to composition (C).

[0181] A final aspect of the present invention relates to a vulcanized composition obtained by the vulcanization process according to the invention.

[0182] Example - preparation of a vulcanization activator composition

[0183] ZnO, CaCOa, linseed oil, and MgO were mixed in a mixer. The mixer was equipped with a thermocouple to measure the temperature. All ingredients were added at the same time in the proportions specified in Table 1. The maximum temperature during mixing and the mixing time are also specified in Table 1.

[0184] The unsaturated fatty acid residue composition of the used linseed oil is summarized in Table 2. In addition, the used linseed oil 5 comprising between 5 and 18% by weight of saturated fatty acids relative to the total weight of said linseed oil. The percentages of the different fatty acid residues can be measured by ISO 12966 or any other equivalent standard. ZnO had a D50 between 1 pm and 100 pm.

[0185] Table 1

[0186] 10

[0187] The BET specific surface area was measured on the final composition (A). The specific surface area is close to 0, which tends to demonstrate that the ZnO (and CaCOa and MgO) core is totally or almost totally covered with linseed oil.

[0188] 15 Table 2 The composition obtained in Example 4 was not dusty, unlike the other compositions obtained in Examples 1, 2, 3 and 5.

[0189] The compositions of Examples 1 to 5 and 7 were powder compositions in which ZnO, CaCOa and MgO were the major constituents of a core at least partially covered with a layer of linseed oil. The composition of Example 6 was a pasty composition.

[0190] The composition according to Example 8 was a powdery composition in which ZnO and MgO were the major constituents of a core at least partially covered with a layer of linseed oil.

[0191] The angle of repose is smaller for example 7 than for example 8. The angle of repose is smaller for example 8 than for comparative example 1.

[0192] The skilled person knows how to measure an angle of repose. For example, a defined volume (e.g. 150 ml) of a composition whose angle of repose is to be measured is taken and placed in a funnel placed above and in the center of a flat-bottomed cylinder. For example, the outlet of the funnel may be located 7.5 cm from the top of the cylinder. The entire defined volume is allowed to flow out. Once all the product has flowed out, the height in mm of the pyramid formed is measured. Using a trigonometric formula, the angle at the base of the pyramid is measured and constitutes the angle of repose.

[0193] Example - use of compositions of compositions (A) in a vulcanization process

[0194] Each of the compositions (A) obtained in examples 2, 3, 4, and 6 was mixed in a mixer with ingredients whose nature and proportions are shown in table 3. Table 3

[0195] The mechanical properties of the vulcanized rubbers are listed in Table 4. The same process was repeated with ZnO instead of composition (A) of Examples 2, 3, 4, and 6, this being the “ZnO” example (comparative example).

[0196] Table 4

[0197] The oscillating disc rheometer allows the duration of vulcanization to be determined by measuring the start time of vulcanization.

[0198] (Ts2) and the time related to the end of vulcanization (t90). The maximum torque

[0199] (Cmax) measured during the rheological test allows the values ​​of ts2 and t90 to be determined. The variation of the torques gives an indication of the crosslinking rate of the product obtained after vulcanization. All rheometry measurements were taken at a temperature of 170°C.

[0200] The maximum torque corresponds to the measurement of the vulcanized (cured) product. In fact, to maintain a stable oscillation of the rheometer disc in both frequency and amplitude, the device's motor provides what is called a variable torque. The latter depends on the elasticity / viscosity of the product being tested. Therefore, the more viscous or elastic the product, the higher the torque.

[0201] The measurements Cmin, Cmax, TR, Ts2, T50, T90 were carried out with an oscillating disk rheometer according to ASTM D5289 standard at a temperature of 170°C.

[0202] The R / R (breaking strength) was measured according to standard NF T 46-002.

[0203] Hardness measurements (SH-A hardness) were carried out according to ISO7619-1 2010.

[0204] The tear measurements were carried out according to standard NF T 46-007.

[0205] As can be observed, the mechanical properties of the different examples are comparable, which tends to show that the presence of vegetable oil has no influence or has a negligible influence on the mechanical properties of the vulcanized polymers.

[0206] Zinc release tests

[0207] Zinc release tests were carried out on the rubbers obtained after vulcanization using composition (a) of example 6 and ZnO (comparative example).

[0208] For each rubber sample, a 10 cm by 8 cm piece was cut. Each piece of rubber was divided and cut into about twenty small 2 cm by 2 cm squares. Each small square was weighed. Each small square was cleaned successively 3 times in 3 aluminum cups with Milli-Q water.

[0209] The small squares were placed directly into 250 ml glass bottles after rinsing and topped with 200 ml of Milli-Q water. The bottles were capped. One bottle was filled with Milli-Q water as a reference.

[0210] Each bottle was placed in an oven at 35°C and shaken daily for 4 weeks. A sample from each bottle was taken at regular intervals and analyzed by atomic absorption according to FD T 90-112. The results of the bottle water analysis are reported in Table 5.

[0211] Table 5

[0212] As can be seen, the amount of ZnO released by the rubber resulting from vulcanization using composition (A) of example 6 releases very little ZnO, moreover the amount of ZnO released does not seem to change over time. The opposite is observed when standard ZnO is used for vulcanization.

Claims

CLAIMS 1. Process for preparing a vulcanization activator composition [hereinafter, composition (A)], said process comprising at least one mixing step: • at least 5% by weight and at most 95% by weight, preferably at least 5% by weight and at most 75% by weight of particles of an oxygenated zinc compound [hereinafter, compound (OZ)], and • at least 1% by weight and at most 75% by weight of at least one vegetable oil or at least one derivative of a vegetable oil, thus forming composition (A), the % by weight being based on the total weight of said composition (A); wherein said vegetable oil or the derivative of a vegetable oil comprises, based on the total weight of said vegetable oil or the derivative of a vegetable oil: at least 8% by weight of at least one fatty acid residue; said fatty acid residue comprising at least two unsaturations.

2. The method of claim 1, wherein said mixing step further comprises mixing at least 0.1% by weight and at most 75% by weight of magnesium oxide, based on the total weight of said composition (A).

3. A method according to any one of the preceding claims, wherein said mixing step further comprises mixing at least 10% by weight and at most 80% by weight of at least one inorganic base, based on the total weight of said composition (A).

4. A method according to any one of the preceding claims, wherein said vegetable oil is selected from the group consisting of linseed oil, walnut oil, sunflower oil, corn oil, avocado oil, hemp oil, grapeseed oil, olive oil, peanut oil, rice oil, sesame oil, soybean oil, rapeseed oil, safflower oil, wheat germ oil and mixtures thereof.

5. A method according to any one of the preceding claims, wherein said derivative of a vegetable oil is a derivative of an oil selected from the group consisting of linseed oil, walnut oil, sunflower oil, corn oil, avocado oil, hemp oil, grapeseed oil, olive oil, peanut oil, rice oil, sesame oil, soybean oil, rapeseed oil, safflower oil, wheat germ oil, palm oil and mixtures thereof.

6. Process according to any one of the preceding claims, wherein said fatty acid residue is a C12-C30 residue, more preferably C14-C28, more preferably C14-C26, even more preferably C14-C24, more preferably C16-C24, more preferably C16-C22, more preferably C16-C20, even more preferably C18.

7. A method according to any one of the preceding claims, wherein said vegetable oil and / or said vegetable oil derivative comprises at least 15% by weight of said fatty acid residue, more preferably at least 20% by weight of said fatty acid residue, even more preferably at least 25% by weight of said fatty acid residue, more preferably at least 30% by weight of said fatty acid residue, more preferably at least 35% by weight of said fatty acid residue, even more preferably at least 40% by weight of said fatty acid residue, even more preferably at least 50% by weight of said fatty acid residue, based on the total weight of said vegetable oil or said vegetable oil derivative.

8. A method according to any one of the preceding claims, wherein said vegetable oil and / or said vegetable oil derivative comprises at most 80% by weight of said fatty acid residue, more preferably at most 75% by weight of said fatty acid residue, even more preferably at most 70% by weight of said fatty acid residue, based on the total weight of said vegetable oil or said vegetable oil derivative.

9. A method according to any one of the preceding claims, wherein said fatty acid residue is a residue selected from the group consisting of residues of α-linolenic acid, γ-linolenic acid, dihomo-γ-linolenic acid, arachidonic acid, eicosapentaenoic acid, docosahexaenoic acid and linoleic acid.

10. A method according to any one of the preceding claims, wherein said fatty acid residue is a fatty acid residue (A) comprising two unsaturations and said vegetable oil and / or said vegetable oil derivative further comprises a fatty acid residue (B) comprising at least three unsaturations.

11. A method according to any one of the preceding claims, wherein said fatty acid residue (A) is a residue of linoleic acid and said fatty acid residue (B) is a residue selected from the group consisting of residues of α-linolenic acid, γ-linolenic acid, dihomo-γ-linolenic acid, arachidonic acid, eicosapentaenoic acid and docosahexaenoic acid and linoleic acid.

12. A method according to any one of the preceding claims, wherein at least 10% by weight of said compound (OZ), more preferably at least 12% by weight, more preferably at least 15% by weight, more preferably at least 20% by weight, more preferably at least 25% by weight, more preferably at least 30% by weight, more preferably at least 40% by weight, more preferably at least 50% by weight, more preferably at least 60% by weight of said compound (OZ) based on the total weight of said composition (A) are mixed in said mixing step.

13. Method according to any one of the preceding claims, in which at most 70% by weight of said compound (OZ), more preferably at most 65% by weight, more preferably at most 55% by weight, more preferably at most 50% by weight, more preferably at most 45% by weight, more preferably at most 40% by weight, more preferably at most 35% by weight of said compound (OZ) based on the total weight of said composition (A), are mixed in said mixing step.

14. A method according to any one of the preceding claims, wherein said compound (OZ) has a D50 of at least 100 nm, more preferably at least 200 nm, even more preferably at least 300 nm, even more preferably at least 400 nm, even more preferably at least 500 nm, even more preferably at least 600 nm, even more preferably at least 700 nm, even more preferably at least 800 nm, even more preferably at least 1 pm, even more preferably at least 2 pm, measured by laser particle size analysis in water.

15. A method according to any preceding claim, wherein said compound (OZ) may have a D50 of at most 500 pm, or at most 100 pm, or at most 20 pm or at most 15 pm, measured by laser particle size analysis in water.

16. A method according to any one of the preceding claims, wherein said compound (OZ) is selected from the group consisting of zinc oxide, zinc hydroxide, zinc carbonate, zinc hydroxycarbonate and mixtures thereof.

17. Method according to any one of the preceding claims, wherein said composition (A) is a pasty or liquid composition, said method comprising at least one mixing step: • at least 20% by weight and at most 60% by weight of particles of a compound (OZ), and • at least 15% by weight and at most 75% by weight of at least one vegetable oil or at least one derivative of a vegetable oil, thus forming composition (A), based on the total weight of said composition (A).

18. Method according to any one of claims 1 to 16, wherein said composition (A) is a powdery composition of at least partially coated particles of compound OZ, said method comprising at least one mixing step: • at least 20% by weight and at most 60% by weight of particles of a compound (OZ), and • at least 1% by weight and at most 35% by weight of at least one vegetable oil or at least one derivative of a vegetable oil, thus forming composition (A), based on the total weight of said composition (A).

19. A method according to any one of claims 2 to 18, wherein at least 0.5% by weight, more preferably at least 0.8% by weight, even more preferably at least 1% by weight of magnesium oxide is mixed in said mixing step.

20. A method according to any one of claims 2 to 19, wherein at most 75% by weight, more preferably at most 70% by weight, even more preferably at most 60% by weight, even more preferably at most 50% by weight, even more preferably at most 40% by weight, even more preferably at most 30% by weight, even more preferably at most 20% by weight, even more preferably at most 10% by weight of magnesium oxide is mixed in said mixing step.

21. A method according to any one of claims 3 to 20, wherein said at least one inorganic base is selected from the group consisting of at least one inorganic base is selected from the group consisting of LiOH, NaOH, KOH, Ca(OH)2, Mg(OH)2, MgO Ü2CO3, Na2CO3, K2CO3, CaCO3, CaO, MgCO3, LiHCOs, NaHCOs, KHCO3, Ca(HCO3)2, Mg(HCO3)2, MgO.CaO and mixtures and / or combinations thereof.

22. Method according to any one of claims 3 to 21, in which at least 13% by weight, more preferably at least 15 % by weight, even more preferably at least 17% by weight of inorganic base are mixed in said mixing step.

23. A method according to any one of claims 3 to 22, wherein at most 75% by weight, more preferably at most 70% by weight, even more preferably at most 65% by weight of inorganic base is mixed in said mixing step.

24. Method according to any one of the preceding claims, wherein said mixing step is carried out at a temperature of at most 100°C, preferably at most 80°C, more preferably at most 70°C, even more preferably at most 60°C, even more preferably at most 50°C, even more preferably at most 40°C.

25. A method according to any one of the preceding claims, wherein said mixing step is carried out at a temperature of at least 10°C, more preferably at least 15°C, more preferably at least 17°C, more preferably at least 20°C.

26. A method according to any preceding claim, wherein said mixing is carried out for at most 30 minutes, or at most 20 minutes, or at most 10 minutes, or at most 5 minutes, or at most 1 minute or at most 30 seconds.

27. A method according to any preceding claim, wherein said mixing is carried out for at least 10 seconds.

28. Vulcanization activator composition obtained by the process according to any one of the preceding claims.

29. Use of the composition according to claim 28 or of a composition obtained by the process according to any one of claims 1 to 27 in a vulcanization process.

30. A process for vulcanizing a vulcanizable composition [composition (C)] comprising, relative to the total weight of the composition (C), the steps of: providing said composition (C) comprising: at least one vulcanizable polymer [polymer (V)] with between 2 and 10 parts by weight of said composition (A) according to claim 28 or obtained by the process according to any one of claims 1 to 27 relative to 100 parts by weight of said polymer (V) and between 0.2 to 15 parts by weight of at least one vulcanizing agent [agent (V)] relative to 100 parts by weight of said polymer (V) to form said composition (C).

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