Polymeric materials

Abstract

(A) a polymer composition (especially a polyester composition) which includes a compound of tungsten and oxygen (especially tungsten oxide particles) and an additional additive, wherein said additional additive is selected from an acetaldehyde scavenger and a colourant, wherein when said polymer composition includes an acetaldehyde scavenger, said polymer composition includes at least 10 ppm (suitably at least 25 ppm, preferably at least 50 ppm) of said acetaldehyde scavenger and when said polymer composition includes a colourant, said polymer composition includes at least SOpprh (suitably at least 75 ppm, preferably at least 100 ppm) of said colourant, wherein: preferably said article is a preform for a container; or (B) a sheet comprising a polymer composition (especially a polyester, polycarbonate or polyolefin composition) which includes a compound of tungsten and oxygen (especially tungsten oxide particles), wherein said sheet has a width of at least G.3 m.

Claims

1. An article comprising: a polymer composition which includes tungsten oxide particles and an additional additive, wherein said additional additive is selected from an acetaldehyde scavenger and a colourant, wherein when said polymer composition includes an acetaldehyde scavenger, said polymer composition includes at least 10 ppm of said acetaldehyde scavenger and when said polymer composition includes a colourant, said polymer composition includes at least 50 ppm of said colourant, wherein said article is a preform for a container; wherein said tungsten oxide particles include 18.86 to 20.64 wt % oxygen; wherein said tungsten oxide particles comprise at least 99 wt % of tungsten and oxygen moieties; wherein at least 99 wt % of said preform is made up of said polymer composition, wherein said polymer composition includes at least 99 wt % of a polyester polymer, wherein said preform has an L* of at least 65, wherein said tungsten oxide particles have a d50 of less than 25 ?m; wherein said tungsten oxide particles have a span (S) from 0.01 to 5 where S is calculated by the following equation:
S=(d.sub.90-d.sub.10)/d.sub.50 where d.sub.90represents a particle size in which 90% of the volume is composed of particles having a smaller diameter than the stated d.sub.90; d.sub.10 represents a particle size in which 10% of the volume is composed of particles having a diameter smaller than the stated d.sub.10 ; and d.sub.50 represents a particle size in which 50% of the volume is composed of particles having a diameter larger than the stated d.sub.50 value and 50% of the volume is composed of particles having a diameter smaller than the stated d.sub.50 value; wherein less than 5 vol % of said tungsten oxide particles have a particle size of more than 100 ?m; and more than 75 vol % of said tungsten oxide particles have a particle size of more than 0.40 ?m.

2. An article according to claim 1, wherein said tungsten oxide particles include 19.4 to 19.9 wt % oxygen.

3. An article according to claim 1, said article including 12 to 100 ppm of said tungsten oxide particles.

4. An article according to claim 1, wherein said tungsten oxide particles have a d.sub.50 of less than 10 ?m and greater than 0.1 ?m.

5. An article according to claim 1, wherein said article includes at least 10 ppm and less than 100 ppm of said tungsten oxide particles and the L* is at least 70.

6. An article according to claim 1, wherein said polyester composition comprises 5 to 150 ppm of tungsten oxide particles, wherein said polyester polymer consists essentially of PET and wherein said tungsten oxide particles include 19. 4 to 19.9 wt % oxygen.

7. An article according to claim 1, wherein said article includes less than 75 ppm of said tungsten oxide particles.

8. An article according to claim 1, wherein said article includes 5 to 50 ppm of said tungsten oxide particles.

9. An article according to claim 1, wherein span (S) is in the range 0.1 to 3.

10. An article according to claim 1, wherein said tungsten oxide particles have a d50 of at least 0.1 ?m.

11. An article according to claim 1, wherein said tungsten oxide particles have a d50 of less than 2?m.

12. An article according to claim 1, wherein said article is a preform in the form of a test-tube shaped injection moulding.

13. An article according to claim 1, wherein said preform has a weight in the range 15 to 40 g and includes 0.00009 g to 0.006 g of said tungsten oxide particles.

14. An article according to claim 1, wherein: said tungsten oxide particles include 19.4 to 19.9 wt % oxygen; said tungsten oxide particles have a d.sub.50 of less than 10 ?m and greater than 0.1 ?m.

15. An article according to claim 1, wherein: said article includes at least 10 ppm and less than 100 ppm of said tungsten oxide particles and the L* is at least 70; wherein said polyester polymer consists essentially of PET; wherein said tungsten oxide particles include 19.4 to 19.9 wt % oxygen; said tungsten oxide particles have a d.sub.50 of less than 10 ?m and greater than 0.1 ?m; and span (S) is in the range 0.1 to 3.

16. An article according to claim 1, wherein: said tungsten oxide particles include 19.4 to 19.9 wt % oxygen; said tungsten oxide particles have a d50 of at least 0.5 ?m; said article is a preform in the form of a test-tube shaped injection moulding; span (S) is in the range 0.1 to 3; and said preform includes at least 10 ppm and less than 100 ppm of said tungsten oxide particles.

17. An article comprising, a polymer composition which includes tungsten oxide particles and an additional additive, wherein said additional additive is selected from an acetaldehyde scavenger and a colourant, wherein when said polymer composition includes an acetaldehyde scavenger, said polymer composition includes at least 10ppm of said acetaldehyde scavenger and when said polymer composition includes a colourant, said polymer composition includes at least 50 ppm of said colourant, wherein said article is a preform for a container; wherein said tungsten oxide particles include 18.86 to 20.64 wt % oxygen; wherein said tungsten oxide particles comprise at least 99 wt % of tungsten and oxygen moieties; wherein at least 99 wt % of said preform is made up of said polymer composition, wherein said polymer composition includes at least 99 wt % of a polyester polymer, wherein said preform has an L* of at least 65, wherein said tungsten oxide particles have a d50 of less than 25 ?m; wherein said tungsten oxide particles have a span (S) from 0.01 to 5 where S is calculated by the following equation:
S=(d.sub.90-d.sub.10)/d.sub.50 where d.sub.90represents a particle size in which 90% of the volume is composed of particles having a smaller diameter than the stated d.sub.90; d.sub.10 represents a particle size in which 10% of the volume is composed of particles having a diameter smaller than the stated d.sub.10; and d.sub.50 represents a particle size in which 50% of the volume is composed of particles having a diameter larger than the stated d.sub.50 value and 50% of the volume is composed of particles having a diameter smaller than the stated d.sub.50 value wherein said article includes 50 ppm or less of said tungsten oxide particles; and wherein said tungsten oxide particles have a d.sub.50 of less than 10 ?m and greater than 0.1 ?m.

18. An article according to claim 17, wherein less than 5 vol % of said tungsten oxide particles have a particle size of more than 100 ?m; and more than 75 vol % of said tungsten oxide particles have a particle size of more than 0.40 ?m.

19. An article comprising a polymer composition which includes tungsten oxide particles and an additional additive, wherein said additional additive is selected from an acetaldehyde scavenger and a colourant, wherein when said polymer composition includes an acetaldehyde scavenger, said polymer composition includes at least 10 ppm of said acetaldehyde scavenger and when said polymer composition includes a colourant, said polymer composition includes at least 50 ppm of said colourant, wherein said article is a preform for a container; wherein said tungsten oxide particles include 18.86 to 20.64 wt % oxygen; wherein said tungsten oxide particles comprise at least 99 wt % tungsten and oxygen moieties; wherein at least 99 wt % of said preform is made up of said polymer composition, wherein said polymer composition includes at least 99 wt % of a polyester polymer, wherein said preform has an L* of at least 65, wherein said tungsten oxide particles have a d50 of less than 25 ?m; wherein said tungsten oxide particles have a span (S) from 0.01 to 5 where S is calculated by the following equation:
S=(d.sub.90-d.sub.10)/d.sub.50 where d.sub.90 represents a particle size in which 90% of the volume is composed of particles having a smaller diameter than the stated d.sub.90d.sub.10 represents a particle size in which 10% of the volume is composed of particles having a diameter smaller than the stated d.sub.10; and d.sub.50 represents a particle size in which 50% of the volume is composed of particles having a diameter larger than the stated d.sub.50 value and 50% of the volume is composed of particles having a diameter smaller than the stated d.sub.50 value, wherein said tungsten oxide particles have a d50 of at least 0.5 ?m.

Description

(1) Specific embodiments of the invention will now be described, by way of example, with reference to the accompanying figures in which:

(2) FIG. 1 is a graph of preform reheat temperature v. active loading for a series of additives:

(3) FIG. 2 is a graph of light transmission v. active loading for a series of additives;

(4) FIG. 3 is a graph of preform a* v. active loading for a series of additives;

(5) FIG. 4 is a graph of preform b* v. active loading for a series of additives;

(6) FIG. 5 is a graph of preform light transmission (%) v. peak preform reheat temperature (? C.);

(7) FIG. 6 is a graph providing particle size data for Dispersions A, B and C;

(8) FIG. 7 is a graph of preform L.* v. preform reheat temperature for a series of additives; and

(9) FIG. 8 is a graph of preform b* v. active loading for a series of additives.

(10) The following materials are referred to hereinafter:

(11) WO-Atungsten oxide (oxygen content 20.70%)

(12) WO-Btungsten oxide (oxygen content 20.64%)

(13) WO-Ctungsten oxide (oxygen content 19.71%)

(14) WO-Dtungsten oxide (oxygen content 10.32%)

(15) Tungsten material (W)oxygen content less than 500 ppm

(16) WO-Etungsten oxide (oxygen content 18:86%)

(17) The aforementioned materials are commercially available. Unless otherwise stated, the reductive state and levels of oxygen described herein are evaluated applying ASTM E159-10 Standard Test Method for Loss Mass in Hydrogen for Cobalt, Copper, Tungsten and Iron Powders.

(18) Unless otherwise stated, the particle sizes described herein were examined using a Beckman Coulter LS230 Laser Diffraction Particle Size Analyzer, fitted with a Micro Volume Module filled with dichloromethane. The samples were pre-diluted in mineral oil before addition to the module.

(19) Titanium nitridecommercially available titanium nitride reheat additive.

(20) C93a polyester control material which includes no reheat additive.

(21) U1activated carbon reheat additive sold by Polytrade, having D50=<0.5 ?m and a maximum particle size of 2 ?m.

(22) Optical, for example L*a*b*, data for preforms was measured in transmittance using a Minolta CM-3700d spectrophotometer (D65 illumination 10? observer, specular included, UV included) linked to an IBM compatible PC. Tests are undertaken using a standard preform holder supplied by Minolta.

(23) All tungstate powders evaluated were prepared into dispersions of active powder in a carrier system compatible with the polymer host. The carrier has no influence on host polymer colour, transmission or haze values at the levels used when moulded parts were transmission measured in their amorphous state. The carrier also has no impact on the reheat behavior of moulded preforms.

EXAMPLE 1

Preparation of Preforms

(24) Liquid dispersions comprising the reheat additives in a carrier medium were formulated and added at the throat of an injection moulding machine onto dry C93 polymer. Preforms were then made from the polymer, using a 160-ton HUSKY injection moulding machine which made two preforms per shot. The injection moulding was conducted at 285? C. Each preform weighed approximately 35 grams and was cylindrical, approximately 105 mm in length with a screw top base and 3.7 mm side wall thickness. The preforms could be blown into one litre bottles with a petaloid base.

EXAMPLE 2

Method for Assessing Reheat

(25) Preforms for all samples/batches are stored in the same area and are allowed to condition for at least 24 hours to ensure that all the preforms being tested are of the same starting temperature.

(26) Standard settings are entered into a Sidel SB-01 stretch blow moulding machine. The machine houses two banks of ovens each bank containing 9?1500 W+1?2000 watt infra red heating lamps, 10 lamps per oven 20 lamps in total.

(27) A set throughput rate is entered which is 1000 b/p/h (bottles per hour). At this production rate the preforms take approximately 45 seconds to pass through the ovens. As the preforms pass through the ovens they are automatically rotated at a constant rate so the entire outside surface of the preforms are equally exposed to the oven lamps.

(28) The machine heating coefficient is switched off (this is a function that when active automatically controls the energy supplied to the oven lamps in an attempt to guide the preform reheat temperature to a predetermined set point) as a set amount of I.R. energy is supplied to every preform so there is no bias.

(29) Each lamp is set at 60% power and a master energy setting that controls the power to every lamp is also set to 60%. At these conditions the oven lamps are all operating at 60% of 60% of their maximum operating ability.

(30) After the preforms pass through the ovens there is approximateiy a 3 second conditioning period (no I.R. energy exposure) before they pass an infra red camera that measures the preform surface temperature. The camera is connected to a data capture station which records all preform surface temperatures as they pass by.

(31) A minimum of five preforms from a batch are tested and an average reheat figure gained. Preforms representing each batch are entered into the machine in a staggered formation so no one batch gains any bias. By way of example, if a comparison is to be drawn of the reheat behaviour of three different resins (A, B and C), a minimum of 5 preforms produced from each resin would be selected for reheat testing and the preforms would be entered into the machine in a random order (e.g. A-C-B-B-C-C-A-C-B-A-C-A-A-B-B, not all A's, then B's then C's). An average reheat figure would then be gained for each set of preforms.

(32) The reheat improvement (defined as a temperature attained by the test preform minus the temperature attained by a C93 control (i.e. not containing any reheat additive)) was calculated.

(33) Various evaluations on the materials referred to were undertaken as described in the following examples to establish the reheat material with the best combination of properties.

EXAMPLE 3

Comparison of Reheat v. Active Loading

(34) The preform reheat temperature v. active loading was assessed for various tungsten oxides of different stoichiometries and for commercially available titanium nitride and activated carbon (U1) materials. The results are provided in FIG. 1.

(35) Referring to FIG. 1, the results show that, of the tungsten samples evaluated, WO-C returned the best reheat v. active loading. TiN returned the best reheat performance per ppm active loading, with U1 between TiN and the best tungsten oxides.

EXAMPLE 4

Comparison of Light Transmission v. Active Loading

(36) The preform light transmission v. active loading for various materials was assessed and the results are provided in FIG. 2.

(37) Although as referred to in Example 3, TiN has the best reheat performance per ppm of active loading, it is clear from FIG. 2 that it has the greatest impact on preform light transmission. It will be appreciated that the amount of a reheat additive which can be used in a preform is dependent upon how the additive affects polymer aesthetics. From FIG. 2, it is clear that WO-C has the best reheat per ppm additive (FIG. 1) and it does not block as much transmitted light as the WO-E or WO-D (FIG. 2).

EXAMPLE 5

Comparison of Preform a* and b* v. Active Loading

(38) In addition to the factors evaluated as described in Examples 3 and 4, it is also desirable for a reheat additive not to adversely affect the polymer's a* and b* colour. It may also be desirable for the additive to impart a neutral or slightly positive (i.e. red) effect on a*, and a slightly negative (i.e. blue) effect on b*. Such attributes would give the active toning properties.

(39) FIGS. 3 and 4 provide results for preform a* v active loading and preform b* v. active loading respectively. From the Figures, it is noted that, of the tungsten-based materials, it is the tungsten metal, the WO-A and the WO-B, which provide the best influence on a*, however, these materials return the worst reheat performance. The b* results show that, although WO-E and WO-D give the preferred blue toning effect, their detrimental impact on general light transmission is greater than for the WO-C sample. It will be noted that the WO-C has a relatively neutral effect on b*, has a very similar influence on a* and has the best reheat uptake performance in comparison to the WO-D end WO-E materials. WO-C therefore appears to be the best all round performer.

(40) Results used to compile FIGS. 1 to 4 are summarised in Table 1. D65 is a standard light source.

(41) TABLE-US-00001 TABLE 1 a* b* Efficacy L*(D65) (D65) (D65) Reheat Efficacy average C93 Control 84.78 ?0.28 1.71 94.33 N/A N/A WO-A-12.5 ppm 81.96 ?0.09 2.23 94.64 0.11 0.11 WO-A-25 ppm 78.97 0.03 2.87 95.07 0.13 WO-A-50 ppm 73.35 0.32 4.07 95.69 0.12 WO-A-75 ppm 68.36 0.53 5.05 95.90 0.10 WO-B-12.5 ppm 82.80 ?0.56 3.01 97.00 1.35 1.21 WO-B-25 ppm 80.93 ?0.91 4.39 98.97 1.20 WO-B-50 ppm 77.11 ?1.49 6.76 103.39 1.18 WO-B-75 ppm 73.36 ?1.94 9.00 106.99 1.11 WO-C-12.5 ppm 82.29 ?1.44 1.72 99.77 2.19 1.81 WO-C-25 ppm 79.74 ?2.55 1.84 103.74 1.87 WO-C-50 ppm 74.72 ?4.66 2.15 111.50 1.71 WO-C-75 ppm 70.17 ?6.32 2.47 115.83 1.47 WO-E-12.5 ppm 81.71 ?1.38 0.56 99.27 1.61 1.44 WO-E-25 ppm 79.17 ?2.55 0.12 102.99 1.54 WO-E-50 ppm 73.73 ?4.61 ?0.79 109.64 1.39 WO-E-75 ppm 68.74 ?6.33 ?1.54 114.04 1.23 WO-D-12.5 ppm 81.85 ?1.44 0.77 99.46 1.75 1.52 WO-D-25 ppm 79.35 ?2.36 0.01 103.77 1.74 WO-D-50 ppm 73.89 ?4.13 ?1.14 109.40 1.38 WO-D-75 ppm 68.76 ?5.72 ?1.91 113.54 1.20 W-12.5 ppm 83.61 ?0.38 1.08 95.49 0.99 0.92 W-25 ppm 82.84 ?0.27 0.96 96.36 1.04 W-50 ppm 80.55 ?0.31 0.85 97.86 0.83 W-75 ppm 78.34 ?0.33 0.73 99.64 0.83 U1-2 ppm 81.37 ?0.22 1.69 95.01 0.20 0.46 U1-4 ppm 78.21 ?0.13 2.05 97.64 0.50 U1-6 ppm 75.06 ?0.04 2.28 99.71 0.55 U1-8 ppm 72.07 0.01 2.51 101.07 0.53 U1-10 ppm 69.10 0.11 2.72 102.41 0.52 TiN-2 ppm 81.34 ?0.74 0.66 96.54 0.64 0.71 TiN-4 ppm 77.89 ?1.15 ?0.26 99.37 0.73 TiN-6 ppm 74.89 ?1.53 ?1.02 101.86 0.76 TiN-8 ppm 71.26 ?1.92 ?2.02 103.84 0.70 TiN-10 ppm 68.41 ?2.23 ?2.95 106.23 0.73

EXAMPLE 6

(42) A relevant indication of the influence a reheat additive has upon a base polymer is to evaluate how it has affected the host polymers L* v. reheat efficacy. Efficacy values (which compare the effect of an additive on polymer reheat against its impact on L*) are quoted in Table 1.

(43) The values are calculated as follows:

(44) $\frac{\begin{array}{c}\mathrm{Polymer}\mathrm{efficacy}=\\ \left(\begin{array}{c}\mathrm{preform}\mathrm{containing}\mathrm{additive}\mathrm{reheat}\mathrm{value}-\\ \mathrm{non}\mathrm{reheat}\mathrm{preform}\mathrm{control}\mathrm{value}\end{array}\right)\end{array}}{\left(\begin{array}{c}{L}^{*}\mathrm{of}\mathrm{non}\mathrm{reheat}\mathrm{preform}-\\ L^{*}\mathrm{of}\mathrm{preform}\mathrm{containing}\mathrm{additive}\end{array}\right).}$

(45) The data shows that adding the market-leading U1 to a polyester to improve its reheat performance actually makes the polymer much worseits impact on the polymer's aesthetics far outweighs any benefit it provides through reheat. In comparison, at optimum loading (12.5 ppm active), the WO-C additive more than doubles the non-reheat control polymers efficacy performance.

EXAMPLE 7

(46) A significant benefit to a polymer having much improved efficacy performance is illustrated by the graph of FIG. 5. The efficacy brings flexibility to polymer manufacturers. For example, referring to FIG. 5, the example highlights a loading of 6 ppm U1 and its impact on preform reheat and L*. This loading would be considered a top of the range reheat product for a carbon based reheat technology. The chart indicates that a preform of similar L* incorporating TiN would return significantly improved reheat performance. A preform produced again of similar L* containing WO-C material would produce what could be considered a super reheat polymer. Alternately the polymer manufacturer has the option of producing a product incorporating WO-C with similar reheat behavior as one containing 6 ppm U1 yet having far superior L*.

(47) The following examples report on experiments undertaken to produce improved (e.g. more cost-effective) dispersions for use in making preforms in the processes described.

EXAMPLE 8

Preparation and Evaluation of Dispersions

(48) Three different dispersions of WO-C were made and evaluated as follows:

(49) Dispersion AWO-C prepared by dispersing 7.5 g of the tungsten oxide in 92.5 g of carrier using a Hamilton Beach disperser for 5 minutes;

(50) Dispersion BWO-C, prepared using optimal milling. This involves 200 g of the tungsten oxide being mixed with 200 g of carrier to form a slurry which was added to a 250 ml Eiger Terence horizontal bead mill containing 0.7-1 mm cerium beads. The mixture was milled by recirculation for 1 hour.

(51) FIG. 6 includes particle size information of particles in Dispersions A and B. It is understood that the milling has not reduced particles sizes further but has broken down the large agglomerations above 4 ?m in particle size. All the particles are found to be greater than 0.375 ?m but, for Dispersion B, the mean particle sizes have been reduced. Those values are provided in Table 2.

(52) TABLE-US-00002 TABLE 2 Dispersion D.sub.50 WOC Reference particle size (?m) A 13.2 B 0.946

(53) Preform L* v. preform reheat temperature was assessed for Dispersions A, and B, U1 and TiN and results are provided in FIG. 7.

(54) FIG. 7 highlights that Dispersion B (having smaller average particle size and a narrower particle size distribution) produces preforms with better efficacy, the benefits of which are less material is required to achieve a targeted reheat range; the seine reheat behaviour can be achieved with better light transmission; and a cheaper product can be offered to customers.

(55) Preform b* v. active loading was assessed for Dispersions A and B, U1 and TiN and results are provided in FIG. 8. The figure shows that reducing the particle size of additive particles in the dispersion has brought about a desired blue toning. However, advantageously, compared to TiN, for WO-C material, the effect is not as severe and, consequently, higher loadings of WO-C material can be incorporated into polymers before the preform appears too blue. Further significant reduction in particle size of the WO-C is found to increase the blueing and make the material more like TiN; so reducing particle sizes much further is disadvantageous, due to too much toning.

(56) When adding, TiN neutrality of the b* axis is achieved in the example shown at approximately 3.75 ppm active addition. At this point the preform would start to gain a blue/green tint. In comparison much higher additions of WO-C could be made before this blue/green tint appears. Adding U1 makes the polymer more yellow indicating the manufacturer may need to add additional blue toners to neutralize this effect. Additional toner would result in further loss in polymer L*.

(57) It has been noted that preforms containing Dispersion A return a three times better performance to that of those containing U1. Also, Dispersion B shows that reducing the particle size to the range indicated results in more reheat gain across the loading range compared to the impact it has on preform transmission or L* loss. This influence has brought about increased polymer efficacy.