FLUOROPOLYMER COMPOSITION COMPRISING A COLOURING COMPOUND

Abstract

The present invention pertains to a fluoropolymer composition comprising an organic colouring compound, to a process for the manufacture of said composition and to uses of said composition in various applications.

Claims

1. A composition (C) comprising: at least one fluorinated thermoplastic elastomer, and at least one organic colouring compound, wherein said fluorinated thermoplastic elastomer comprises: at least one block (A) consisting of at least one elastomeric fluoropolymer, and at least one block (B) consisting of at least one thermoplastic fluoropolymer.

2. The composition (C) according to claim 1, wherein the fluorinated thermoplastic elastomer comprises one or more repeating structures of type B-A-B.

3. The composition (C) according to claim 1, wherein the elastomeric fluoropolymer of the block (A) of the fluorinated thermoplastic elastomer has a heat of fusion of less than 5 J/g, as measured according to ASTM D3418-08.

4. The composition (C) according to claim 1, wherein the elastomeric fluoropolymer of the block (A) of the fluorinated thermoplastic elastomer is selected from the group consisting of: (1) vinylidene fluoride (VDF) copolymers, wherein VDF is copolymerized with at least one fluorinated monomer; and (2) tetrafluoroethylene (TFE) copolymers, wherein TFE 15 copolymerized with at least one fluorinated monomer.

5. The composition (C) according to claim 1, wherein the elastomeric fluoropolymer of the block (A) of the fluorinated thermoplastic elastomer comprises: from 45% to 90% by moles of recurring units derived from vinylidene fluoride (VDF), from 5% to 50% by moles of recurring units derived from at least one fluorinated monomer different from VDF, and optionally, up to 30% by moles of recurring units derived from at least one hydrogenated monomer.

6. The composition (C) according to claim 1, wherein the thermoplastic fluoropolymer of the block (B) of the fluorinated thermoplastic elastomer has a heat of fusion of from 10 J/g to 90 J/g, as measured according to ASTM D3418-08.

7. The composition (C) according to claim 1, wherein the thermoplastic fluoropolymer of the block (B) of the fluorinated thermoplastic elastomer comprises: recurring units derived from vinylidene fluoride (VDF), optionally, from 0.1% to 10% by moles of recurring units derived from at least one fluorinated monomer different from VDF, and optionally, recurring units derived from at least one hydrogenated monomer.

8. The composition (C) according to claim 1, wherein the weight ratio between blocks (A) and blocks (B) in the fluorinated thermoplastic elastomer is typically comprised between 5:95 and 95:5.

9. The composition (C) according to claim 1, wherein the fluorinated thermoplastic elastomer is obtained by a process comprising the following sequential steps: (a) polymerizing at least one fluorinated monomer, and optionally at least one hydrogenated monomer, in the presence of a radical initiator and of an iodinated chain transfer agent, thereby providing a pre-polymer consisting of at least one block (A) containing one or more iodinated end groups; and (b) polymerizing at least one fluorinated monomer, and optionally at least one hydrogenated monomer, in the presence of a radical initiator and of the pre-polymer provided in step (a), thereby providing at least one block (B) grafted on said pre-polymer by means of the iodinated end groups.

10. The composition (C) according to claim 1, wherein the organic colouring compound is a luminescent colouring compound or a non-luminescent colouring compound.

11. A process for the manufacture of the composition (C) according to claim 1, said process comprising compounding at least one fluorinated thermoplastic elastomer and at least one organic colouring compound.

12. An article comprising the composition (C) according to claim 1.

13. (canceled)

14. A method for manufacturing an article, the method comprising using the composition (C) according to claim 1 as processing aid.

15. A process for the manufacture of the article according to claim 12, said process comprising processing a composition comprising at least one polymer, in the presence of a composition (C), using a melt-processing technique selected from compression moulding, injection moulding and extrusion moulding, wherein composition (C) comprises: at least one fluorinated thermoplastic elastomer, and at least one organic colouring compound, wherein said fluorinated thermoplastic elastomer comprises: at least one block (A) consisting of at least one elastomeric fluoropolymer, and at least one block (B) consisting of at least one thermoplastic fluoropolymer.

16. The composition (C) according to claim 3, wherein the elastomeric fluoropolymer of the block (A) of the fluorinated thermoplastic elastomer has a heat of fusion of less than 3 J/g, as measured according to ASTM D3418-08.

17. The composition (C) according to claim 6, wherein the thermoplastic fluoropolymer of the block (B) of the fluorinated thermoplastic elastomer has a heat of fusion of from 30 J/g to 60 J/g, as measured according to ASTM D3418-08.

18. The composition (C) according to claim 8, wherein the weight ratio between blocks (A) and blocks (B) in the fluorinated thermoplastic elastomer is typically comprised between 20:80 and 80:20.

19. The composition (C) according to claim 1, wherein the elastomeric fluoropolymer of the block (A) of the fluorinated thermoplastic elastomer is selected from the group consisting of: (1) vinylidene fluoride (VDF) copolymers, wherein VDF is copolymerized with at least one fluorinated monomer; and (2) tetrafluoroethylene (TFE) copolymers, wherein TFE is copolymerized with at least one fluorinated monomer; and the thermoplastic fluoropolymer of the block (B) of the fluorinated thermoplastic elastomer comprises: recurring units derived from vinylidene fluoride (VDF), optionally, from 0.1% to 10% by moles of recurring units derived from at least one fluorinated monomer different from VDF, and optionally, recurring units derived from at least one hydrogenated monomer.

20. The composition (C) according to claim 19, wherein the elastomeric fluoropolymer of the block (A) of the fluorinated thermoplastic elastomer comprises: from 45% to 90% by moles of recurring units derived from vinylidene fluoride (VDF), from 5% to 50% by moles of recurring units derived from at least one fluorinated monomer different from VDF, and optionally, up to 30% by moles of recurring units derived from at least one hydrogenated monomer.

Description

PREPARATIVE EXAMPLE 1: BLOCK COPOLYMER HAVING STRUCTURE PVDF-P(VDF-HFP)-PVDF (P(VDF-HFP) VDF: 78.5% BY MOLES, HFP: 21.5% BY MOLES)

[0187] In a 7.5 liters reactor equipped with a mechanical stirrer operating at 72 rpm, 4.5 l of demineralized water and 22 ml of a microemulsion, previously obtained by mixing 4.8 ml of a perfluoropolyoxyalkylene having acidic end groups of formula CF.sub.2ClO(CF.sub.2CF(CF.sub.3)O).sub.n(CF.sub.2O).sub.mCF.sub.2COOH, wherein n/m=10, having an average molecular weight of 600, 3.1 ml of a 30% v/v NH.sub.4OH aqueous solution, 11.0 ml of demineralized water and 3.0 ml of GALDEN D02 perfluoropolyether of formula CF.sub.3O(CF.sub.2CF(CF.sub.3)O).sub.n(CF.sub.2O).sub.mCF.sub.3, wherein n/m=20, having an average molecular weight of 450, were introduced.

[0188] The reactor was heated and maintained at a set-point temperature of 85 C.; a mixture of vinylidene fluoride (VDF) (78.5% by moles) and hexafluoropropylene (HFP) (21.5% by moles) was then added to reach a final pressure of 20 bar. Then, 8 g of 1,4-diiodoperfluorobutane (C.sub.4F.sub.8I.sub.2) as chain transfer agent were introduced, and 1.25 g of ammonium persulfate (APS) as initiator were introduced. Pressure was maintained at a set-point of 20 bar by continuous feeding of a gaseous mixture of vinylidene fluoride (VDF) (78.5% by moles) and hexafluoropropylene (HFP) (21.5% by moles) up to a total of 2000 g. Moreover, 0.86 g of CH.sub.2CH(CF.sub.2).sub.6CHCH.sub.2, fed in 20 equivalent portions each 5% increase in conversion, were introduced.

[0189] Once 2000 g of monomer mixture were fed to the reactor, the reaction was discontinued by cooling the reactor to room temperature. The residual pressure was then discharged and the temperature brought to 80 C. VDF was then fed into the autoclave up to a pressure of 20 bar, and 0.14 g of ammonium persulfate (APS) as initiator were introduced. Pressure was maintained at a set-point of 20 bar by continuous feeding of VDF up to a total of 500 g. Then, the reactor was cooled, vented and the latex recovered. The latex was treated with aluminum sulphate, separated from the aqueous phase, washed with demineralized water and dried in a convection oven at 90 C. for 16 hours.

[0190] Characterization data of the polymer so obtained are reported in Table 1.

PREPARATIVE EXAMPLE 2:P(VDF-HFP) FLUOROELASTOMER (VDF: 78.5% BY MOLES, HFP: 21.5% BY MOLES)

[0191] In a 7.5 liters reactor equipped with a mechanical stirrer operating at 72 rpm, 4.5 l of demineralized water and 22 ml of a microemulsion, previously obtained by mixing 4.8 ml of a perfluoropolyoxyalkylene having acidic end groups of formula CF.sub.2ClO(CF.sub.2CF(CF.sub.3)O).sub.n(CF.sub.2O).sub.mCF.sub.2COOH, wherein n/m=10, having an average molecular weight of 600, 3.1 ml of a 30% v/v NH.sub.4OH aqueous solution, 11.0 ml of demineralized water and 3.0 ml of GALDEN D02 perfluoropolyether of formula CF.sub.3O(CF.sub.2CF(CF.sub.3)O).sub.n(CF.sub.2O).sub.mCF.sub.3, wherein n/m=20, having an average molecular weight of 450, were introduced.

[0192] The reactor was heated and maintained at a set-point temperature of 85 C.; a mixture of vinylidene fluoride (VDF) (78.5% moles) and hexafluoropropylene (HFP) (21.5% moles) was then added to reach a final pressure of 20 bar. Then, 8 g of 1,4-diiodoperfluorobutane (C.sub.4F.sub.8I.sub.2) as chain transfer agent were introduced, and 1.25 g of ammonium persulfate (APS) as initiator were introduced. Pressure was maintained at a set-point of 20 bar by continuous feeding of a gaseous mixture of vinylidene fluoride (VDF) (78.5% moles) and hexafluoropropylene (HFP) (21.5% moles) up to a total of 2000 g. Moreover, 0.86 g of CH.sub.2CH(CF.sub.2).sub.6CHCH.sub.2, fed in 20 equivalent portions each 5% increase in conversion, were introduced. Then, the reactor was cooled, vented and the latex recovered. The latex was treated with aluminum sulphate, separated from the aqueous phase, washed with demineralized water and dried in a convection oven at 90 C. for 16 hours.

[0193] Characterization data of the polymer so obtained are reported in Table 1.

[0194] As shown in Table 1 here below, the fluorinated thermoplastic elastomer of the present invention as notably embodied by the block copolymer of Preparative Example 1 according to the invention surprisingly has a glass transition temperature lower than the glass transition temperature of the corresponding fluoroelastomer as notably embodied by the fluoroelastomer of Preparative Example 2.

TABLE-US-00001 TABLE 1 DSC Prep. Ex. 1 Prep. Ex. 2 T.sub.g [ C.] 21.5 18.0 T.sub.m [ C.] 162.5 Composition - NMR soft (A) hard (B) VDF [% mol] 78.5 100 78.5 HFP [% mol] 21.5 21.5

EXAMPLE 1

[0195] A composition was prepared by mixing using an open mill mixer the following components: [0196] 100 phc of the block copolymer obtained according to Preparative Example 1 of the invention, said polymer being extruded in pellets, [0197] 0.24 phc of TiO.sub.2, and [0198] 0.007 phc of a colouring compound based on diketopyrrolopyrrole commercially available as Pigment Red 254.

[0199] Plaques were subsequently obtained by compression moulding for 5 min at 190 C.

[0200] The resulting colour was evaluated by calculating the E94 value on the final plaque by reference to the colour of the initial mixture by means of a X-Rite Ci7800 spectrophotometer using a D65-10 light, according to ASTM D2244 standard.

[0201] Colour measurement on the initial mixture was carried out on a plaque with a shape similar to that of the final plaque and obtained by moulding said mixture at temperatures slightly above the room temperature in order to avoid any chemical or thermal transformation.

[0202] E94 is a measure of change in visual perception of two given colours and is thus a measure of the ability of a material containing a colouring compound to retain its colour as close as possible to the original colour of the colouring compound.

[0203] On a typical scale, the E94 value ranges from 0 to 100.

[0204] The lowest the E94 value, the highest the colour retention properties of the material.

[0205] The results are reported in Table 2.

EXAMPLE 2

[0206] The same procedure as detailed under Example 1 was followed but replacing the colouring compound with 0.05 phc of a fluorescent colouring compound based on thioxanthene commercially available as Solvent Orange 63.

[0207] The results are reported in Table 2.

COMPARATIVE EXAMPLE 1

[0208] A compound was prepared by mixing the fluoroelastomer obtained according to Preparative Example 2 with curing agents in the following composition: [0209] 100 phr of the fluoroelastomer obtained according to Preparative Example 2, [0210] 1.5 phr of LUPEROX 101 XL 45 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane, and [0211] 4 phr of DRIMIX triallyl isocyanurate (75%).

[0212] A composition was then prepared by mixing using an open mill mixer the following components: [0213] 100 phc of the compound so obtained, [0214] 0.24 phc of TiO.sub.2, and [0215] 0.007 phc of a colouring compound based on diketopyrrolopyrrole commercially available as Pigment Red 254.

[0216] The composition so obtained was moulded into a plaque and post-cured according to the following procedure: [0217] curing for 5 minutes at 160 C., [0218] post-cure for 2 hours at 175 C.

[0219] The resulting colour was evaluated by calculating the E94 value on the final plaque by reference to the colour of the initial mixture by means of a X-Rite Ci7800 spectrophotometer using a D65-10 light, according to ASTM D2244 standard.

[0220] Colour measurement on the initial mixture was carried out on a plaque with a shape similar to that of the final plaque and obtained by moulding said mixture at temperatures slightly above the room temperature in order to avoid any chemical or thermal transformation.

[0221] The results are reported in Table 2.

COMPARATIVE EXAMPLE 2

[0222] The same procedure as detailed under Comparative Example 1 was followed but replacing the colouring compound with 0.05 phc of a colouring compound based on thioxanthene commercially available as Solvent Orange 63.

[0223] The results are reported in Table 2.

TABLE-US-00002 TABLE 2 Run E94 Ex. 1 0.32 C. Ex. 1 2.23 Ex. 2 2.57 C. Ex. 2 10.33

[0224] In view of the above, it has been surprisingly found that the composition of the present invention, said composition comprising a fluorinated thermoplastic elastomer and a colouring compound, as notably embodied by the compositions of Examples 1-2 according to the invention, is advantageously capable of retaining its original colour as compared to a composition based on a fluoroelastomer as notably embodied by the compositions of Comparative Examples 1-2, respectively, as shown by the values of E94 as set forth in Table 2.