Multilayer assembly

Abstract

The present invention pertains to a multilayer assembly, to a process for the manufacture of said multilayer assembly, to a pipe comprising said multilayer assembly and to uses of said pipe in various applications.

Claims

1. A multilayer assembly comprising: a metal substrate, said metal substrate having an inner surface and an outer surface, a layer (L1) consisting of a composition (C1) comprising at least one polymer (F), wherein polymer (F) is a fluoropolymer, at least one benzoxazine compound (B) and at least one aromatic polymer (P), said layer (L1) having a first surface and a second surface, wherein the first surface of layer (L1) is at least partially adhered to at least one of the inner surfaces and the outer surface of said metal substrate, a layer (L2) consisting of a composition (C2) comprising at least one functional polymer (F), wherein functional polymer (F) is a functional fluoropolymer comprising: predominantly recurring units of tetrafluoroethylene (TFE) 0.5 to 30% by weight of at least one per(halo) fluoromonomer (PFM) different from TFE; and one or more polar functional groups selected from the group consisting of carboxylic groups in acid, acid halide or salt form, sulfonic groups in acid, acid halide or salt form, epoxide groups, silyl groups, alkoxysilane groups, hydroxyl groups and isocyanate groups, said layer (L2) having a first surface and a second surface, wherein the first surface of layer (L2) is at least partially adhered to the second surface of said layer (L1), and a layer (L3) consisting of a composition (C3) comprising at least one polymer (F), wherein polymer (F) is a fluoropolymer, onto layer (L2).

2. The multilayer assembly according to claim 1, wherein the PFM is at least one per(halo)fluoroalkylvinylether.

3. The multilayer assembly according to claim 1, wherein the compound (B) of composition (C1) is of formula (I): ##STR00033## wherein each of R.sub.a, equal or different at each occurrence, is H or a C.sub.1-C.sub.12 alkyl group; R, is a C.sub.1-C.sub.36 hydrocarbon group, optionally comprising one or more heteroatoms, optionally comprising at least one benzoxazine group; j is zero or an integer of 1 to 4; and each of RC, equal or different at each occurrence, is a halogen atom or a C.sub.1-C.sub.36 hydrocarbon group, optionally comprising one or more heteroatoms, optionally comprising at least one benzoxazine group.

4. The multilayer assembly according to claim 1, wherein functional polymer (F) of composition (C2) is manufactured by irradiation of at least one polymer (F) using either a photon source or an electron source.

5. The multilayer assembly according to claim 1, wherein functional polymer (F) of composition (C2) is manufactured by polymerization of at least one fluorinated monomer with at least one functional fluoro-alkylvinylether of formula CF.sub.2═CFOY.sub.0, wherein Y.sub.0 is a C.sub.1-C.sub.12 alkyl or (per)fluoro-alkyl group, or a C.sub.1-C.sub.12 oxyalkyl or a C.sub.1-C.sub.12 (per)fluorooxyalkyl group, said Y.sub.0 group comprising a carboxylic group in its acid, acid halide or salt form or a sulfonic group in its acid, acid halide or salt form.

6. The multilayer assembly according to claim 1, wherein functional polymer (F) of composition (C2) comprises one or more polar functional groups selected from the group consisting of carboxylic groups in acid, acid halide or salt form and sulfonic groups in acid, acid halide or salt form.

7. The multilayer assembly according to claim 3, wherein polymer (F) of composition (C1) is a TFE copolymer comprising at least 4% by weight of recurring units derived from at least one per(halo)fluoromonomer (PFM).

8. The multilayer assembly according to claim 4, wherein polymer (F) of composition (C1) is a TFE copolymer comprising at most 20% by weight of recurring units derived from at least one per (halo)fluoromonomer (PFM).

9. The multilayer assembly according to claim 1, wherein polymer (P) of composition (C1) is selected from the group consisting of aromatic polyimide polymers (PI).

10. The multilayer assembly according to claim 9, wherein the polymer (PI) is an aromatic polyamide-imide polymer (PAI).

11. The multilayer assembly according to claim 1, wherein in said layer (L3), said polymer (F) of the composition (C3) is selected from the group consisting of copolymers of tetrafluoroethylene (TFE) with at least one per(halo) fluoromonomer (PFM) different from TFE, said layer (L3) having a first surface and a second surface, wherein the first surface of layer (L3) is at least partially adhered to the second surface of layer (L2).

12. The multilayer assembly according to claim 11, wherein composition (C3) further comprises at least one filler.

13. The multilayer assembly according to claim 12, wherein the filler is selected from the group consisting of inorganic and organic fillers.

Description

EXAMPLE 1: GENERAL PROCEDURE FOR THE MANUFACTURE OF A MULTILAYER ASSEMBLY

(1) Carbon steel substrates (15×4×0.5 cm panels) were treated by grit blasting using aluminium oxide (10 mesh).

(2) A primer composition (C1) was prepared according to the general procedure as detailed above, said primer composition (C1) comprising: 16% by weight of the polymer (F-1), 17% by weight of a composition comprising the compound (B-1) and the polymer (P-1) in a weight ratio of 12:1, 50% by weight of a liquid medium comprising the solvent (S-1) and DMSO in a weight ratio of 1:1, and complement to 100% by weight of one or more fillers.

(3) Fillers suitable for use in the primer composition (C1) include DYNAMIX™ BLACK 30C.sub.965 black pigment commercially available from Shepherd Color Company, BYK® 9076 liquid rheology control additive consisting of a solution of a high molecular urea modified medium polar polyamide commercially available from BYK, TECO® Airex 931 deaerator/defoaming agent for solvent-based coating systems based on a fluorinated silicone commercially available from Evonik Tego Chemie GmbH, TERGITOL™ 15-S-3 secondary alcohol ethoxylate surfactant commercially available from Dow, and NUBIROX® 106 pigment commercially available from Nubiola.

(4) The primer composition (C1) so obtained was applied on the so treated carbon steel substrates by spray coating using a gun with a die of 1.2 mm and air pressure of 2.5 bar.

(5) A mid-coat composition (C2) was prepared by irradiation of the polymer (F-2) according to the general procedure as detailed above thereby providing a functional fluoropolymer comprising 21 mmol/Kg of —COOH end groups and 2.3 mmol/Kg of —COF end groups, said functional fluoropolymer having a melt flow index of 59 g/10 min, as measured according to ASTM D 1238 standard method at 372° C. under a load of 5 Kg.

(6) The mid-coat composition (C2) so obtained was then applied onto the wet primer layer by electrostatic powder coating (45 kV, 15 μA).

(7) A top-coat composition (C3) was then prepared, said composition comprising 90% by weight of polymer (F-1), 5% by weight of mica and 5% by weight of poly(sulfonyl-p-phenylene).

(8) A first layer of the top-coat composition (C3) so obtained was applied onto the mid-coat layer by electrostatic powder coating (45 kV, 15 μA). The multilayer assembly so obtained was heated in an oven at 345° C. for 15 minutes. The thickness of the overall multilayer assembly so obtained was comprised between 50 μm and 100 μm.

(9) A second layer of the top-coat composition (C3) so obtained was applied onto the mid-coat layer by electrostatic powder coating (45 kV, 15 μA). The multilayer assembly so obtained was heated in an oven at 330° C. for 15 minutes. A third layer of the top-coat composition (C3) so obtained was applied onto the mid-coat layer by electrostatic powder coating (45 kV, 15 μA). The multilayer assembly so obtained was heated in an oven at 330° C. for 15 minutes.

(10) The thickness of the overall multilayer assembly so obtained was comprised between 100 μm and 200 μm.

EXAMPLE 2: GENERAL PROCEDURE FOR THE MANUFACTURE OF A MULTILAYER ASSEMBLY

(11) Carbon steel substrates (15×4×0.5 cm panels) were treated by grit blasting using aluminium oxide (10 mesh).

(12) A primer composition (C1) was prepared according to the general procedure as detailed above, said primer composition (C1) comprising: 7.97% by weight of the polymer (F-1), 17.34% by weight of the compound (B-1), 1.49% by weight of the polymer (P-1), 60.24% by weight of a liquid medium comprising the solvent (S-1) and DMSO in a weight ratio of 1:1, and complement to 100% by weight of one or more fillers.

(13) Fillers suitable for use in the primer composition (C1) include DYNAMIX™ BLACK 30C.sub.965 black pigment commercially available from Shepherd Color Company, BYK® 9076 liquid rheology control additive consisting of a solution of a high molecular urea modified medium polar polyamide commercially available from BYK, TECO® Airex 931 deaerator/defoaming agent for solvent-based coating systems based on a fluorinated silicone commercially available from Evonik Tego Chemie GmbH, TERGITOL™ 15-S-3 secondary alcohol ethoxylate surfactant commercially available from Dow, and NUBIROX® 106 pigment commercially available from Nubiola.

(14) The primer composition (C1) so obtained was applied on the so treated carbon steel substrates by spray coating using a gun with a die of 1.2 mm and air pressure of 2.5 bar.

(15) A mid-coat composition (C2) was prepared, said composition comprising 30% by weight of the TFE/PMVE/VEFS functional polymer (F) prepared according to the general procedure as detailed above and 70% by weight of polymer (F-1).

(16) The mid-coat composition (C2) so obtained was then applied onto the wet primer layer by electrostatic powder coating (45 kV, 15 μA).

(17) A top-coat composition (C3) was then prepared, said composition comprising 90% by weight of polymer (F-1), 8% by weight of mica and 2% by weight of talc.

(18) A first layer of the top-coat composition (C3) so obtained was applied onto the mid-coat layer by electrostatic powder coating (45 kV, 15 μA). The multilayer assembly so obtained was heated in an oven at 345° C. for 15 minutes. The thickness of the overall multilayer assembly so obtained was comprised between 50 μm and 100 μm.

(19) A second layer of the top-coat composition (C3) so obtained was applied onto the mid-coat layer by electrostatic powder coating (45 kV, 15 μA). The multilayer assembly so obtained was heated in an oven at 330° C. for 15 minutes. A third layer of the top-coat composition (C3) so obtained was applied onto the mid-coat layer by electrostatic powder coating (45 kV, 15 μA). The multilayer assembly so obtained was heated in an oven at 330° C. for 15 minutes.

(20) The thickness of the overall multilayer assembly so obtained was comprised between 100 μm and 200 μm.

COMPARATIVE EXAMPLE 1: MANUFACTURE OF A MULTILAYER ASSEMBLY

(21) The same procedure as detailed under Example 1 was followed but without applying the mid-coat composition (C2) onto the primer composition (C1).

COMPARATIVE EXAMPLE 2: MANUFACTURE OF A MULTILAYER ASSEMBLY

(22) The same procedure as detailed under Example 1 was followed but replacing the mid-coat composition (C2) with a composition consisting of polymer (F-1) and the primer composition (C1) with a composition comprising: 7.97% by weight of the polymer (F-1), 17.34% by weight of the compound (B-1), 1.49% by weight of the polymer (P-1), 60.24% by weight of a liquid medium comprising the solvent (S-1) and DMSO in a weight ratio of 1:1, and complement to 100% by weight of one or more fillers.
Rapid Gas Decompression Test

(23) Adhesion of the top-coat layer to the inner layer of panels of multilayer assemblies was tested according to the Autoclave Test following NACE™ 0185 standard procedure. Samples of test panels were prepared and suspended in a beaker where test fluids were added and then the beaker was placed into an autoclave unit. The unit was secured and gases were metered into the unit using partial pressures. The heat was turned on and the pressure was monitored until full temperature was reached. The panels were in this way suspended in an autoclave containing either of the following three phases:

(24) Test A

(25) (1-A) 75% CH.sub.4— 25% CO.sub.2,

(26) (2-A) hydrocarbon—toluene/kerosene (50/50), and

(27) (3-A) water containing 5% by weight of NaCl,

(28) according to the following test conditions:

(29) temperature: 180° C.,

(30) pressure: 4000 psi,

(31) duration: 48 hours (timed from achievement of stable conditions),

(32) decompression rate: 180° C., 5000 psi/min, or

(33) Test B

(34) (1-B) 79% CH.sub.4— 5% CO.sub.2— 16% H.sub.2S,

(35) (2-B) hydrocarbon—toluene/kerosene (50/50), and

(36) (3-B) water containing 5% by weight of NaCl,

(37) according to the following test conditions:

(38) temperature: 163° C.,

(39) pressure: 7000 psi,

(40) duration: 24 hours (timed from achievement of stable conditions),

(41) decompression rate: 163° C., 6500 psi/min.

(42) After depressurization, the test panel was removed and examined within one hour for blistering change and adhesion in accordance with NACE™ 0185 standard procedure.

(43) Blister size was rated by comparison with photographic standards in FIGS. 1-4 (in the standard) according to ASTM D 714-02 using the following scale: blister size from 10 to 0 (10 being no blisters). Blister size #8 represents blisters whose diameters are so small that they are barely visible with the unaided eye. Blister sizes #6, #4, and #2 represent increasingly larger blister sizes. Blister size #2, e.g. has blisters measuring 4 to 5 mm in diameter. Blister sizes #1 and #0 have increasingly larger blister sizes. These details on blister sizes are given to enable the visualization of these sizes without resorting to the photographic standards, but are not intended as a substitute for reliance on the photographic standards for the actual rating of blister size. Blister frequency is D (dense), Medium Dense (MD), Medium (M) and Few (F). A blister frequency of None means that no blisters (blister size of #10) are visible when viewed with the unaided eye.

(44) Adhesion was evaluated by the Knife Adhesion Test wherein the top-coat layer was scribed using a knife thereby providing 30° “V”-cut scribes. This scribing was done on the panels after being subjected to the Autoclave Test conditions at each of the three phases levels according to Test A or Test B. A knife blade was then inserted into one of the scribes in an attempt to lift the top-coat layer from the surface of the panel.

(45) The adhesion of the top-coat layer in the multilayer assembly is rated as follows:

(46) A—no change,

(47) B—slight loss of adhesion—some resistance to lifting; coating not peeled back to full extent of “V”-cut scribes,

(48) C—moderate loss of adhesion—coating lifted with slight resistance but peeled back to end of “V”-cut scribes,

(49) D—severe loss of adhesion—coating readily lifted with little resistance,

(50) E—disbondment—delamination; coating lifted when cut.

(51) The results are summarized in Table 1 here below.

(52) TABLE-US-00001 TABLE 1 Adhesion Adhesion Adhesion Run Blisters [phase (1)] [phase 2)] [phase (3)] Ex. 1 #10 A A A (Test A) (Test A) (Test A) (Test A) Ex. 2 #10 A A A (Test B) (Test B) (Test B) (Test B) C. Ex. 1  #0 E E E (Test A) (Test A) (Test A) (Test A) C. Ex. 2 #10 C E E (Test A) (Test A) (Test A) (Test A)

(53) It has been thus found that multilayer assembly of the invention as notably represented by the multilayer assembly of any of Examples 1 and 2 according to the invention successfully exhibits outstanding interlayer adhesion properties as compared with the multilayer assembly of any of Comparative Examples 1 and 2 while maintaining good anti-corrosion and good thermal insulation properties to be suitably used in oil and gas applications without undergoing decompression under the effect of pressure impacts.