POLYMERIC MATERIALS

Abstract

A method of producing a product, for example a stretch blow moulded container having a metallic or pearlescent appearance, comprises selecting a mass, for example a container preform, comprising a thermoplastic polymer which incorporates a carrier polymer and stretching the thermoplastic polymer during production of said product, for example from said mass. Said carrier polymer is suitably polydimethylsiloxane and the mass may be made in a process which comprises contacting a thermoplastic polymer with a liquid formulation comprising carrier polymer and colourant.

Claims

1-37. (canceled)

38. A method of producing a product, the method comprising: (i) selecting a mass comprising a thermoplastic polymer which incorporates a carrier polymer, wherein said carrier polymer includes oxygen atoms and silicon atoms in its backbone; and (ii) stretching the thermoplastic polymer during production of said product from said mass.

39. A method according to claim 38, wherein said carrier polymer is a polydialkylsiloxane.

40. A method according to claim 38, wherein said carrier polymer includes a repeat unit of formula ##STR00003## wherein R.sup.1 and R.sup.2 both represent C.sub.1-2 un-substituted alkyl moieties.

41. A method according to claim 38, wherein said carrier polymer is polydimethylsiloxane.

42. A method according to claim 38, wherein said method includes a step (i)* which precedes step (i) and comprises contacting said carrier polymer with said thermoplastic polymer.

43. A method according to claim 42, wherein step (i)* of the method takes place in a melt-processing apparatus and said carrier polymer is dosed into said thermoplastic polymer when said thermoplastic polymer is in a molten state.

44. A method according to claim 43, wherein said thermoplastic polymer is contacted with a formulation which comprises said carrier polymer, wherein said formulation comprises: (i) said carrier polymer; and (ii) a colourant; wherein said formulation is a liquid.

45. A method according to claim 44, wherein said formulation includes 0 wt % of laminar or plate-like pigments; includes 0 wt % of metallic colourant; and includes 0 wt % of pearlescent colourant.

46. A method according to claim 44, wherein at least 95 wt % of the total amount of colourant(s) in said formulation have a maximum dimension which is less than 200μm.

47. A method according to claim 44, wherein said formulation comprises 80 to 99 wt % of polydimethylsiloxane and 1 to 20 wt % in total of one or more colourants.

48. A method according to claim 44, wherein, in said formulation, the sum of the wt % of all carrier polymers which include a repeat unit of formula ##STR00004## wherein R.sup.1 and R.sup.2 both represent C.sub.1-2 un-substituted alkyl moieties and all colourants is at least 95 wt %.

49. A method according to claim 44, wherein, in said formulation, the sum of the wt % of polydimethylsiloxane and all colourants is at least 98 wt %.

50. A method according to claim 42, wherein in step (i)* a mixture is formed comprising carrier polymer and thermoplastic polymer and the mass selected in step (i) includes said mixture, wherein said mass includes at least 0.5 wt % of carrier polymer and at least 95 wt % of thermoplastic polymer and said mass includes 0-2 wt % of colourant(s).

51. A method according to claim 38, wherein, in said mass, the ratio of the wt % of carrier polymer divided by the vvt% of thermoplastic polymers is in the range 0.05 to 0.005.

52. A method according to claim 51, wherein said thermoplastic polymer is a polyester.

53. A method according to claim 38, wherein a precursor of the product is made and isolated prior to step (ii) of the method, wherein said precursor is a preform for a bottle.

54. A method according to claim 38, wherein step (ii) comprises stretching the thermoplastic polymer in at least two directions.

55. A method according to claim 38, which comprises production of a bottle from a preform by contacting thermoplastic polymer with a carrier polymer; injection moulding a mixture comprising the thermoplastic polymer and carrier polymer to produce a preform; and subsequently stretch blow-moulding the preform to produce a product in the form of a bottle.

56. A method of producing a product, the method comprising: (i)* contacting a formulation with a thermoplastic polymer which is a polyester to produce a mass comprising said thermoplastic polymer which incorporates said formulation, wherein step (i)* takes place in a melt-processing apparatus and said formulation is dosed into said thermoplastic polymer when said thermoplastic polymer is in a molten state, wherein said formulation is a liquid and comprises a carrier polymer and a colourant, wherein said formulation includes 0 wt % of laminar or plate-like pigments includes 0 wt % of metallic colourant and includes 0 wt % of pearlescent colourant, wherein, in said formulation, the sum of the wt % of all carrier polymers which include a repeat unit of formula ##STR00005## wherein R.sup.1 and R.sup.2 both represent C.sub.1-2 un-substituted alkyl moieties and all colourants is at least 95 wt %, wherein said carrier polymer is polydimethylsiloxane, wherein said formulation comprises 80 to 99 wt % of polydimethylsiloxane and 1 to 20 wt % in total of one or more colourants; (i) selecting said mass comprising said thermoplastic polymer which incorporates said formulation, wherein said mass includes at least 0.5 wt % of carrier polymer and at least 95 wt % of thermoplastic polymer and said mass includes 0-2 wt % of colourant(s) and wherein, in said mass, the ratio of the wt % of carrier polymer divided by the wt % of thermoplastic polymers is in the range 0.05 to 0.005; (ii) stretching the thermoplastic polymer in at least two directions during production of said product from said mass; wherein a precursor of the product is made and isolated prior to step (ii) of the method, wherein said precursor is a preform for a bottle.

57. A product which comprises a stretched thermoplastic polymer in the form of a bottle produced in a method of claim 38, wherein in said product said thermoplastic polymer is a polyester and said carrier polymer is polydimethylsiloxane.

Description

[0087] Specific embodiments of the invention will now be described by way of example, with reference to the accompanying figures, wherein:

[0088] FIG. 1 provides results of a Turbiscan assessment of the Example 20 formulation;

[0089] FIG. 2 provides results of a Turbiscan assessment of the Example 21 formulation.

[0090] The following materials are referred to hereinafter:

[0091] PDMS-1—refers to polydimethylsiloxane having a viscosity at 25° C. of 12,500 centistokes a viscosity temperature coefficient of 0.60, a specific gravity at 25° C. of 0.975, a refractive index at 25° C. of 1.4035, a pour point of −46° C., a flash point of 321° C. and a surface tension of 21.3 dynes/cm at 25° C.

[0092] PDMS-2—refers to polydimethylsiloxane having a viscosity at 25° C. of 1,000 centistokes a viscosity temperature coefficient of 0.60, a specific gravity at 25° C. of 0.974, a refractive index at 25° C. of 1.4035, a pour point of −50° C., a flash point of 321° C. and a surface tension of 21.3 dynes/cm at 25° C.

[0093] The following examples 1 to 14 describe the preparation of liquid dispersions (which do not include metallic pigments) for addition to thermoplastics to produce a metallic effect; Example 15 describes a general method for colour concentrate preparation; Example 16 describes a general method for making preforms; Example 17 provides a general method for producing bottles from preforms; and Example 18 includes the results of assessments on the bottles.

EXAMPLES 1 TO 14

Preparation of Liquid Dispersions

[0094] Liquid dispersion colour concentrates were prepared by dispersing dyes or pigments into PDMS-1 or PDMS-2 using a high speed mixer. Details of the formulations are provided in Tables 1 and 2. Note that all amounts in the tables are weight % (wt %).

TABLE-US-00001 TABLE 1 Ingredient Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 PDMS-1 100 98.59 98.65 97.61 97.80 90.12 82.01 Solvent Red — 0.88 1.21 0.80 — 4.32 7.86 135 Disperse — 0.31 — 1.39 — — — Yellow 241 Solvent — 0.22 — 0.20 — 4.18 7.62 Green 3 Solvent Red — — 0.08 — 2.0 — — 195 Solvent — — 0.06 — — — — Violet 13 Pigment — — — — 0.20 — — Violet 23 Solvent Blue — — — — — 1.38 2.51 104

TABLE-US-00002 TABLE 2 Example Example Example Example Example Ingredient Example 8 Example 9 10 11 12 13 14 PDMS-2 100 98 99 94.51 98 98 95.34 Solvent — — — — — — — Green 3 Solvent — — — — — — — Yellow 114 Pigment — 1.57 — 4.33 — — — Yellow 147 Pigment — 0.43 1 1.16 0.5 0.5 — Violet 23 Solvent Red — — — — 1.50 — 0.27 195 Disperse — — — — — 1.50 — Orange 47 Solvent Blue — — — — — — 1.19 104 Solvent Red — — — — — — 3.89 135 Solvent — — — — — — 0.31 Violet 13

[0095] The viscosity of formulations in Table 1 ranged from 12,500 centistokes to 16,000 centistokes at 25° C. The viscosity of formulations in Table 2 ranged from 1000 centistokes to 2000 centistokes at 25° C.

EXAMPLES 15 TO 21

[0096] Further liquid dispersion colour concentrates were prepared by dispersing dyes or pigments into PDMS-1 using a high speed mixer. Details of the formulations are provided in Table 3. Examples 16 to 19 and 21 include cetyl dimethicone, a surfactant together with fumed silica, added as a rheology modifier.

TABLE-US-00003 TABLE 3 Example Example Example Example Example Example Example Ingredient 15 16 17 18 19 20 21 PDMS-1 100 83.75 92.45 79.25 83.75 97.61 96.51 Cetyl 0.75 0.30 1 0.75 0.1 Dimethicone from Basildon Chemicals BC (surfactant) Calcium — 15 — — — — — Carbonate Fumed Silica — 0.50 1 0.50 0.50 — 1 Solvent Red — — 6.25 16 — — — 195 Solvent — — — 3 — — — Yellow-114 Carbon Black — — — 0.25 — — — Solvent Blue — — — 15 — — 104 Disperse — — — — — 1.39 1.39 Yellow 241 Solvent Red — — — — — 0.80 0.80 135 Solvent Green 3 — — — — — 0.20 0.20

[0097] The initial viscosity of the formulations in Table 3 ranged from 12,500 centistokes to 16,000 centistokes at 25° C.

EXAMPLE 22

Assessment of Storage Stability of Formulations of Examples 20 and 21

[0098] A Turbiscan technique was used to assess suspension stability (and therefore storage stability) of formulations with a view to providing a means of providing formulations which are stable against sedimentation and/or flocculation over a long period of time (e.g. up to 9 months). The technique uses the relationship between transmitted or back-scattered light with the concentration of dispersed solids in a liquid suspension. The machine uses standard measurement cells that are scanned with a LED light source along a vertical axis of the cell. The transmitted or back scattered light is measured v. height, to give a profile across the cell in order to give an indirect measurement of the solids concentration profile through the height of the sample. By measuring the cell repeatability, data can be built up over time to give an indication of suspension stability,

[0099] Results for Examples 20 and 21 are provided in FIGS. 1 and 2 respectively.

[0100] FIG. 1 shows that the formulation begins to show noticeable sedimentation after 20 days. By 40 days, the product had clearly flocculated and settled significantly. However, as is clear from FIG. 2, the addition of surfactant and rheology modifier significantly reduces flocculation and no sedimentation was observed up to 9 months.

EXAMPLE 23

General Method for Colour Concentrate Preparation

[0101] 800 g of dried polyethylene terephthalate (PET) polymer pellets (C93 Virgin PET from Equipolymers, dried at 160° C. for 3 hours) were introduced into a 1 litre container. 2 wt % of the liquid dispersion selected from Examples 1 to 21 was added to the container. A lid was applied to the container and the contents were shaken manually or stirred with a spatula until the polymer pellets were fully coated with dispersion. These steps were repeated for each dispersion of Examples 1 to 21.

EXAMPLE 24

General Method for Making Preforms

[0102] A colour concentrate made as described in Example 23 was let down into PET by introducing the concentrate made as described in Example 23 into one feeder and dried PET pellets into a separate feeder of a 160-ton HUSKY (Trade Mark) injection moulding machine fitted with appropriate tooling. In each case, 2 parts by weight (pbw) of concentrate was used per 100 parts of PET.

[0103] The injection moulding was conducted at 285° C. Each preform weighed approximately 35 grams and was cylindrical, approximately 130 mm in length with a screw top base. The preforms could be blown into one litre bottles with a petaloid base.

[0104] Preforms were made using each of the formulations described in Examples 1 to 21. Between use of each formulation, the moulding machine was fully cleaned and purged of residue from a preceding sample using natural uncoloured polymer. After introduction of a new colour concentrate, a sample was manually extruded from the moulding machine until the new colour was observed in the extrudate. The moulding cycle was then started and, after disposing of the first eight preforms, between six and fourteen preforms were collected and retained for subsequent stretch blow moulding. For consistency, in each case, the same preform moulding method was used.

EXAMPLE 25

General Method for Making Bottles

[0105] Preforms made as described in Example 24 were stretch blow moulded, into 1 litre bottles, using a Sidel SB-01 stretch blow moulding machine, with a blowing temperature in the range 105° C. to 120° C.

EXAMPLE 26

Assessment of Bottles

[0106] Bottles blown as described in Example 25 were visually assessed and the results are recorded in Table 4.

TABLE-US-00004 TABLE 4 Liquid dispersion used Aesthetic appearance in bottled manufacture Colour of bottle of bottle Example 1 White Metallic, chrome Example 2 Gold Metallic colour Example 3 Pink Metallic colour Example 4 Gold Metallic colour Example 5 Pink Metallic colour Example 6 Silver Metallic colour Example 7 Black Metallic colour Example 8 White Metallic, chrome Example 9 Red/Green - Red top Metallic colour tone/Green through tone Example 10 Purple Metallic colour Example 11 Red/Green Metallic colour Example 12 Red/Purple Metallic colour Example 13 Red/Orange Metallic colour Example 14 Silver Metallic colour Example 15 White Metallic, chrome Example 16 Opaque White Metallic colour Example 17 Pink Metallic colour Example 18 Red Metallic colour Example 19 Blue Metallic colour Example 20 Gold Metallic colour Example 21 Gold Metallic colour

[0107] As an alternative to letting down the colour concentrate of Example 23 in PET as described in Example 24, it is preferred (especially for large scale production of preforms) to introduce a liquid dispersion (e.g. as described in Examples 1 to 21) directly at the throat of the injection moulding machine to contact and be mixed with PET pellets. Alternatively, the liquid dispersion may be injected downstream of the feed throat into melted PET.

[0108] It should be noted that, in the liquid dispersion, the polydimethylsiloxane (PDMS) is in liquid form and acts as a carrier for the colourant, for example dye. In addition, the PDMS has the effect, upon stretching of the PET containing the PDMS (e.g. as described in Example 25) to produce the metallic-effect described.

[0109] As an alternative to production of PET preforms which are stretched to produce bottles, the liquid dispersion may be added to a wide range of polymeric materials which may be melt-processed and subsequently stretched (uniaxially or biaxially) to produce a product. Suitable polymeric materials may comprise polyesters (e.g. PET), polyolefins (e.g. polypropylene), polycarbonates, acrylics and polystyrenes. Preferably, the liquid dispersion (e.g. comprising PDMS and colourant) is incompatible with the polymeric material used since incompatibility optimises production of the metallic effect described.

[0110] As an alternative to production of bottles, liquid dispersion as described may be added to polymeric materials used to produce biaxial films, sheets, fibres or other articles which involve stretching of a polymeric material in the production of a product.

[0111] The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.