EP1991615A2

EP1991615A2 - Thermoplastic resin-based composition for making single-layer skins or composites with speckled appearance for parts of motor vehicle passenger compartment and method for obtaining same

Info

Publication number: EP1991615A2
Application number: EP07731706A
Authority: EP
Inventors: Ludovic Hardouin-Duparc; Jean-François VAUTRIN
Original assignee: Arkema France SA
Current assignee: Kem One SAS
Priority date: 2006-03-08
Filing date: 2007-03-07
Publication date: 2008-11-19
Also published as: WO2007101968A2; CN101443408A; US20110241254A1; JP2009529083A; WO2007101968A3

Abstract

The invention concerns a thermoplastic resin-based composition, for making single-layer or multilayer skins (or composite structures), having a speckled appearance, and a method for obtaining same. Said composition comprises: 10 to 99 wt. % of a compound or ''matrix'' of a polyvinyl chloride thermoplastic (PVC) resin; 0.5 to 90 wt. % of at least a compound or ''inclusion'' of a thermoplastic resin containing at least one colouring pigment: 0.5 to 20 wt. % of speckling agents selected among colouring pigments, metal particles or decorative flakes, glass beads, polymeric particles.

Description

COMPOSITION BASED ON THERMOPLASTIC RESINS

METHOD FOR THE PRODUCTION OF MONOLAYER SKIN OR COMPOSITES HAVING MOUCHETE APPEARANCE FOR PARTS OF VEHICLE HABITACLE AND METHOD FOR OBTAINING SAME.

The present invention relates to compositions based on thermoplastic resins, allowing the production of "skins" monolayer or multilayer (so-called composite structures), having a speckled appearance, matrix / inclusions type.

Multilayer skins or composite structures comprise an outer layer which can be produced according to the invention and at least one inner layer which can also be produced according to the invention or according to a conventional method; these skins include a matrix and inclusions; these monolayer or multilayer skins are used for passenger compartment parts of motor vehicles, such as in particular dashboards equipped with visible airbags (with separate flaps) or integrated airbags (also known as airbags invisible to the driver and passengers) , central consoles and cladding or door panels.

The invention also relates to the process for producing these compositions, in particular in the form of powders obtained by mixing. PRIOR ART: It is known in the technical field of manufacture of motor vehicle dashboards, to use the skins thereof conventionally made in particular by hot-powder powder flow molding technique, either by rotomolding or by "slush-molding" (abbreviated slush) or slugging.

These dashboards generally include an external "skin" imitation leather that gives the appearance (especially the color, the pattern, the appearance to the touch); Classically, the main materials used are thermoplastic resins such as polyvinyl chloride (PVC), thermoplastic polyurethanes (TPU), and thermoplastic polyolefins (TPO). A foam-based material, usually made of polyurethane or expanded PVC, is used as a sub-layer to provide flexibility properties and sound and thermal insulation.

The outer skin is subjected to external aggressions: scratches, UV radiation, temperature, solvents, etc. In some cases, the "skin" can be made to provide particular properties of appearance, in particular: decoration, color, touch or resistance to aging or abrasion. In addition, monolayer or multilayer skins must comply with the specifications of motor vehicle manufacturers, in particular the requirements for integrated air bag opening or no, that is to say the opening in a very short time without projection of particles for temperatures conventionally between -40 ⁰ C and + 80 ⁰ C.

There are several technologies for producing composite skins having a modified surface, obtained by the application of at least one coating layer on the surface of a mold, in a pre-step of manufacturing a skin.

In particular, the process called "in-mold painting" (IMP), as described in patent EP 0 912 312 of the applicant, comprises the following steps:

1) deposition on the surface of a mold of a composition A comprising at least one plasticizer and optionally one or more modifying agents, chosen in particular from coloring pigments or decorative flakes,

2) depositing on the mold completely or partially coated in 1), a composition B comprising a thermoplastic resin,

3) progressive heating of the mold to allow the absorption of the composition A by the layer of the composition B, then rapid heating until the gelling of the thermoplastic resin.

However, such a method does not allow to obtain a satisfactory heterogeneity of coloration, so-called speckled appearance (or mottled or sandblasted) on the surface of the skin obtained. The Applicant has developed a new composition based on thermoplastic resins for the realization, in particular by "slush molding", of a monolayer or multilayer colored skin with controlled speckled appearance, as well as its method of obtaining.

According to a first object, the invention relates to a composition based on thermoplastic resins with a speckled appearance comprising:

from 10 to 99% by weight of a compound called ("matrix" of a thermoplastic resin of polyvinyl chloride resin (PVC), from 0.5 to 90% by weight of at least one compound called "inclusion" a thermoplastic resin containing at least one coloring pigment,

from 0.5 to 20% by weight of flecking agents chosen from coloring pigments, metal particles or decorative flakes, glass beads, polymeric particles.

According to a second subject, the invention relates to a process for obtaining a composition with a mottled appearance comprising the following steps: a first step of producing a compound based on PVC resin called "matrix", a second step of producing one or more compounds based on PVC resin called "inclusion", by mixing at least one coloring pigment with the PVC resin, a so-called "mouchetage" (or "sanding") step, which consists of mixing the "matrix" compound (s) with the compound (s) at the appropriate rate (s)

"Inclusion" and with one or more flecking agents selected from pigments, metal particles, glass beads, or polymeric particles.

According to a third subject, the invention relates to a composition obtained by the preceding method.

According to a fourth object, the invention also relates to the use of the composition described above for the manufacture of a layer of a monolayer or multilayer skin with speckled appearance for the passenger compartment parts of motor vehicles. According to a fifth subject, the invention relates to a method for producing a skin of a skin layer of a dashboard comprising: depositing the composition defined above on the surface of a mold of shape and ,

- The melting of this composition placed in the mold so that it is converted into a flexible object which is removed from the mold.

The composition according to the invention:

The invention relates to a composition based on thermoplastic resins, for producing a layer of a monolayer or multilayer skin, with a speckled effect, in particular by "slush molding", characterized in that it comprises:

from 10 to 99% by weight of a compound called "matrix" of a thermoplastic resin of polyvinyl chloride resin (PVC),

from 0.5 to 90% by weight of at least one compound called "inclusion" of a thermoplastic resin containing at least one coloring pigment, from 0.5 to 20% by weight of speckling agents chosen from coloring pigments, metallic particles or decorative flakes, glass beads or polymeric particles.

The percentage of inclusion compounds and fluffing agents may, for example, be in the range of 1 to 50% by weight of the composition. The comoound "matrix":

According to the invention, the compound called "matrix" essentially comprises a thermoplastic resin chosen from polyvinyl chloride (PVC) or a mixture of PVC and a compatible polymer selected from copolymers or terpolymers vinyl chloride and vinyl acetate (VC / VA) or vinyl chloride and acrylic derivative (VC / DA), thermoplastic polyurethanes (TPU), thermoplastic polyetheresters, ethylene / vinyl monomer (EVA) copolymers, ethylene / vinyl monomer / carbonyl terpolymers, melt-processable acrylic elastomers, polyamide block and polyether block copolymers or polyether block copolymers, chlorinated or chlorosulfonated polyethylenes, ethylene polymers alkyl (meth) acrylate or functionalized or non-functionalized (meth) acrylic acid, MBS core-shell polymers, SBM block terpolymers, PVDF and polyamide powder resins. According to a preferred embodiment of the invention, the thermoplastic resin used is a Kwert polyvinyl chloride (PVC) of between 50 and 80.

According to one embodiment, the thermoplastic resin is polyvinyl chloride (PVC) obtained by a suspension or micro-suspension process, but emulsion or bulk PVC can also be used. An example of VC / VA copolymer is Lacovyl® from Arkema, an example of VC / DA copolymer is Vinnolit® from Vinnolit, an example of TPU is Goodrich's Estane®, an example of thermoplastic polyetherester is DuPont's Hytrel®, an example of polyetherblockamide is Pebax® from Arkema, an example of EVA is Evatane® from Arkema, an example of ethylene / vinyl monomer / carbonyl terpolymer is Elvaloy® from DuPont, examples of ethylene / alkyl (meth) acrylate or acidic polymers (Meth) acrylic functionalized or otherwise are Lotryl®, Lotader® and Orevac® from Arkema, an example of chlorinated or chlorosulfonated polyethylenes is DuPont's Tyrin®, an example of a processable acrylic elastomer in the molten state is Alcryn® from Apa, an example of polyamide powder resins is Orgasol® from Arkema. These polymers compatible with PVC, called "allies", have good cold properties, and are likely to confer a suitable brittleness to the layers containing them.

According to the invention, suitable mixtures of thermoplastic resins include PVC resins and copolymers or terpolymers vinyl chloride and vinyl acetate (VC / VA) or vinyl chloride and acrylic derivative (VC / DA), as well as PVC resins and thermoplastic polyurethanes (TPU). These different resins can be mixed together in large proportions.

The "matrix" compound may also comprise at least one additive chosen from plasticizers, heat stabilizers or UV stabilizers, antioxidants, processing additives, lubricants, fillers and color pigments called hereinafter matrix pigments. According to one embodiment, the plasticizer (s) used is (are) of monomeric and / or polymeric nature, and is (are) chosen (s) in particular from azelates, trimellitates, sebacates, adipates, polyadipates, phthalates, polyphthalates, citrates, benzoates, tallates, glutarates, fumarates, maleates, oleates, palmitates and acetates. The compound "Matrix" according to the invention also relates to mixtures of polymeric plasticizer (s) and monomeric plasticizer (s), as described above, in very large proportions.

According to one embodiment, the weight ratio of the plasticizers and the resin is at least 60/100. As thermal stabilizing agent, mention may be made, by way of example, of metal salts, in particular those of calcium, zinc and tin; complexes based on aluminum, potassium or sodium.

The anti-UV agents may be chosen from benzotriazoles and cyanoacrylates. The coloring pigments used can be both organic and mineral. By way of example, mention may be made of titanium dioxide, CIBA cromo BRN red pigment, GLSM blue pigment, BRM yellow lime and GL thiosol orange.

According to a preferred embodiment, the coloring pigments, the fillers, the lubricants, the UV stabilizers, the thermal stabilizers, the processing additives and the antioxidants, at levels preferably comprised between 3 and 10% by weight. weight relative to the thermoplastic resin. The compound "inclusion":

According to the invention, the compound "inclusion" comprises at least:

a thermoplastic resin chosen from polyvinyl chloride (PVC) or a mixture of PVC and a compatible polymer chosen from copolymers or terpolymers vinyl chloride and vinyl acetate (VC / VA) or vinyl chloride and acrylic derivative ( VC / DA), thermoplastic polyurethanes (TPU), thermoplastic polyetheresters, ethylene / vinyl monomer copolymers

(EVA), ethylene / vinyl monomer / carbonyl terpolymers, melt-processable acrylic elastomers, polyamide and polyether block copolymers or polyetherblockamides, chlorinated or chlorosulfonated polyethylenes, ethylene / (meth) acrylate polymers or functionalized or non-functionalized alkyl or acid, MBS core-shell polymers, SBM block terpolymers, PVDF and polyamide powder resins, and at least one coloring pigment, said inclusion pigment, different color matrix pigments possibly present in the compound "matrix". The thermoplastic resin of the "inclusion" compound may be identical in nature or different from the "matrix" compound.

The compound "inclusion" may further comprise at least one additive selected from plasticizers, thermal stabilizers or UV stabilizers, antioxidants, processing additives, lubricants or fillers. The agents of moυchetaae:

The speckling (or middling) agents according to the invention are chosen to obtain special effects on the finished product, such as pearlescent, metallized, phosphorescent, fluorescent, thermochromic, interferential, granular or special touch effects, such as soft touch. They have a size in the range of 40 to 200 microns, and more preferably in the range of 50 to 120 microns. They are chosen from coloring pigments, metallic particles or decorative flakes, glass beads or polymeric particles.

The subject of the invention is also the process for preparing the composition according to the invention for obtaining a composition in the form of a powder (in particular a plasticized PVC compound) convertible in particular by conventional slush-molding techniques. ", For the production of" skins "intended for parts of the passenger compartment of motor vehicles. The process according to the invention for the preparation of the above composition:

The process according to the invention for obtaining a composition with a mottled appearance comprises the following steps:

a first step of producing a compound based on PVC resin, called a "matrix" as defined above, a second step of producing at least one compound based on PVC resin called "inclusion", as defined previously, by mixing at least one coloring pigment with the PVC resin,

- A so-called "mouchetage" (or "pinching" or "sanding") step, which consists of mixing the "matrix" compound (s) at the appropriate rate with the "inclusion" compound (s), and with one or more flecking agents, chosen from coloring pigments, metal particles, glass beads, polymeric particles, preferably of density equivalent to that of the material constituting the matrix.

The different steps are carried out using the appropriate tooling, according to a specific and usual mixing method, and with the appropriate implementation parameters. The production of "matrix" and "inclusion" compounds is well known to those skilled in the art. These "matrix" and "inclusion" compounds are presented under the powder form with a well-defined density (on average the density of a PVC resin compound is 1.20 g / cm ³ ), with an average particle size of between 100 and 200 μm and having a flowability adapted to the "slush-molding" process , implemented for obtaining skins. The flecking agents and the inclusion compound (s) are preferably of density equivalent to the "matrix" compound.

The percentage of inclusion compounds and fluffing agents may, for example, be in the range of 1 to 50% by weight of the composition, depending on the desired effect. The present invention also relates to the use of the composition according to the invention, for obtaining a layer of skin or composite structure, for the parts of the passenger compartment of motor vehicles, such as the dashboards, central consoles and cladding or door panels.

The subject of the present invention is a process for producing a monolayer or multi-layered skin layer (composite structure), in particular for a dashboard, comprising depositing the composition defined above on the surface of a mold of a shape. and melting said composition placed in the mold so that it is transformed into a flexible object which is removed from the mold. This composition can be deposited on the mold according to the usual molding techniques such as rotomolding and "slush molding" or sludging. According to a preferred embodiment of the invention, the method used is the fogging.

The skin layers or composite structure obtained according to the invention have a beautiful speckled appearance. They have a controlled heterogeneity of hue, and effect. The following examples illustrate the invention without, however, limiting its scope.

EXAMPLES

1) Example 1 embodiment of a color speckled composition with glass beads according to the invention: An industrial sample of the order of 200 kg of powder for "slush molding" in a defined color and named "Bordeaux Sablé" is prepared. This color consists of a PVC Bordeaux color, mottled (or mottled or sandblasted) by a beige PVC powder.

Step 1: Production of the matrix PVC powder ("matrix" compound) for "slush molding" of Bordeaux color according to the conventional compounding method.

Percentage of the various components expressed by weight: - PVC resin: 50, plasticizers (including especially trioctyl trimellitates (TOTM)): 40,

additives including coloring pigments: 10. (6 different pigments used).

The control of the major properties of the powder gives the following results: apparent density of the order of ό50g / L, color: characterization on one of the existing scales, such as the scale

CIELab, flowability: of the order of 40 s according to the ISO 6186 standard, Method A, 10 mm opening, thermal stability: Congo red at 220 ^° C. in the order of 50 minutes, granulometry: Gaussian distribution of average particle size approaching 170 μm . Step 2: Production of the PVC inclusion powder for "slush molding",

beige inclusion compound according to the conventional compounding method.

The percentage by weight of the various components is identical to that of step 1, only the nature and the amount of the coloring pigments changes. The control of the major properties of the powder gives substantially the same values as for step 1 except for the color.

Step 3: spotting of the Bordeaux powder by an amount of between 5 and 7 phr (parts per cent of resin), ie 7% of the composition, of beige powder, and 2.5 phr of glass beads with a diameter of between 90 and 100 microns sold by the company Sovitec under the reference AG 215 in order to achieve the effect defined by the customer.

The control of the flowability of the powder gives a value of 40 seconds and the visual evaluation of the effect obtained is carried out.

The illustrations of the powders and skins obtained are shown in the following figures: FIG. 1 shows the appearance of the powder obtained after mixing and before the treatment

"Slush molding".

Figure 2 shows the speckled appearance of the skin obtained after the "slush molding" treatment of the powder in a mold.

The differences in color are due in particular to the grain on the surface of the mold and to the "slush molding" process, in particular the heating of the mold.

2) Example 2 of production of speckled composition with coloring pigment according to the invention:

New samples are prepared following the same procedure as in Example 1, with the following differences in the mixing steps:

- A: 100 phr of PVC white matrix powder (pigment used: ΗO2)

B: 66.7 phr beige inclusion PVC powder (4 different pigments used), - C: 28.6 phr of PVC powder inclusion light gray (4 different pigments used), and

D: 3.7 phr of black pigments.

Each of the powders A, B and C has a composition similar to that of the powders of Example 1. Successive blending is carried out with the white powder ("Matrix" compound) forming the matrix, the various inclusion beige, gray (inclusion compound) powders and the black staining pigment (speckling agent).

The results of staining and speckling of the skin obtained by slush molding of the final powder above, are visible in the photo of Figure 3; there are two distinct zones of different appearance (smoother on the right), separated by a vertical central line, which correspond to a surface condition (graining) different from the surface of the mold used to obtain the skin.

3) EXAMPLE 3 OF MAKING A "METALLIZED" FLUID COMPOSITION ACCORDING TO THE INVENTION

A: 33 phr of indigo blue PVC matrix powder (5 different pigments used), B: 33 pcr of burgundy inclusion PVC powder, - C: 33 pcr of clear gray inclusion PVC powder, and

D: 2.5 phr of a metal pigment (metal particles) sold under the reference Magna Pearl 5000.

Each of the powders A, B and C has a composition similar to that of the powders of Example 1. The successive blends are carried out with the blue powder (compound "matrix") forming the matrix, the various powders inclusion burgundy, gray (compound "Inclusion") and metal particles (fluffing agents).

The staining results and the mottled appearance of the skin obtained from the powder, by slush molding, are visible in the picture of FIG.

Claims

R EVE N DI CATI ONS

1. Process for obtaining a composition with a speckled appearance, characterized in that it comprises the following steps: a first step of producing a compound based on PVC resin called "matrix",

a second step of producing one or more compounds based on PVC resin called "inclusion", by mixing at least one coloring pigment with the PVC resin, a so-called "mouchetage" (or "sandblasting") step; ), which comprises mixing at a suitable rate the compound (s) "matrix" with the compound (s) "inclusion" and with one or more speckling agents selected from pigments, metal particles, beads glasses, or polymeric particles.

2. Method according to claim 1, characterized in that it makes it possible to obtain a composition comprising:

from 10 to 99% by weight of a compound called "matrix" of a thermoplastic resin of polyvinyl chloride resin (PVC), from 0.5 to 90% by weight of at least one compound called "inclusion" a thermoplastic resin containing at least one coloring pigment,

3. Method according to one of the preceding claims, characterized in that the percentage of inclusion compounds and speckling agents ranges from 1 to 50% by weight of the composition.

4. Method according to any one of the preceding claims, characterized in that the thermoplastic resin of the compound called "matrix" and / or compound called "inclusion" is polyvinyl chloride Kwert between 50 and 80.

5. Method according to any one of the preceding claims, characterized in that the thermoplastic resin of the compound called "matrix" and / or compound called "inclusion" comprises a polyvinyl chloride mixture (PVC) and a compatible polymer selected from copolymers or terpolymers vinyl chloride and vinyl acetate (VC / VA) or vinyl chloride and acrylic derivative (VC / DA), thermoplastic polyurethanes (TPU), thermoplastic polyetheresters ^', the ethylene / vinyl monomer (EVA), ethylene / vinyl monomer / carbonyl, acrylic elastomers melt processable copolymers having polyamide blocks and polyether blocks or polyétherblockamides, chlorinated or chlorosulphonated polyethylenes, the ethylene / alkyl (meth) acrylate polymers or functionalized or non-functionalized (meth) acrylic acid, MBS core-shell polymers, SBM block terpolymers, PVDF and polyamide powder resins.

6. Method according to any one of the preceding claims, characterized in that the flecking agents have a size in the range of 50 to 120 microns.

7. Composition obtained by the process according to any one of the preceding claims.

8. Composition based on thermoplastic resins, for producing a layer of a monolayer or multilayer skin, with a speckled appearance, characterized in that it comprises:

from 0.5 to 90% by weight of at least one compound called "inclusion" of a thermoplastic resin containing at least one coloring pigment,

9. Composition according to claim 8 characterized in that the thermoplastic resin of the compound called "matrix" and / or the compound named "inclusion" is polyvinyl chloride Kwert between 50 and 80.

10. Composition according to one of claims 8 or 9, characterized in that the thermoplastic resin of the compound "matrix" and / or compound "inclusion" comprises a mixture of polyvinyl chloride (PVC) and a selected compatible polymer among vinyl chloride copolymers or terpolymers and vinyl acetate (VC / VA) or vinyl chloride and acrylic derivative (VC / DA), thermoplastic polyurethanes (TPU), thermoplastic polyetheresters, ethylene / vinyl monomer (EVA) copolymers, ethylene / vinyl monomer / carbonyl terpolymers melt-processable acrylic elastomers, polyamide block and polyether block copolymers or polyetherblockamides, chlorinated or chlorosulfonated polyethylenes, ethylene / alkyl (meth) acrylate polymers or functionalized or non-functionalized (meth) acrylic acids, MBS core-shell polymers, SBM block terpolymers, PVDF and polyamide powder resins.

11. Composition according to one of claims 8 to 10, characterized in that the flecking agents have a size in the range of 50 to 120 microns.

12. Use of the composition according to any one of claims 7 6 1 1, for obtaining a layer of monolayer or multilayer skin, for the parts of passenger compartment of motor vehicles, such as dashboards, the central consoles and cladding or door panels.

13. A method of producing a skin layer of a dashboard, characterized in that it comprises: the deposition of the composition according to any one of claims 7 to 11 on the surface of a mold of form and melting of this composition placed in the mold so that it is transformed into a flexible object which is removed from the mold.

14. The method of claim 13, characterized in that it uses the technique of sludging.