GB2560915A

GB2560915A - Packaging material

Info

Publication number: GB2560915A
Application number: GB1704850.5A
Authority: GB
Inventors: Richard Cockroft Martin; Fisher Luke
Original assignee: Futamura Chemical Uk Ltd
Current assignee: Futamura Chemical Uk Ltd
Priority date: 2017-03-27
Filing date: 2017-03-27
Publication date: 2018-10-03
Also published as: WO2018178058A1; GB201704850D0; EP3601421A1

Abstract

Low density regenerated cellulosic beads with a bulk density of below 450 g/l are claimed. A method of production requires mixing viscose with a salt that reacts with the acid regeneration bath to produce gas when placed in the regeneration bath, causing the bead to expand and become porous. Preferred salts are metal carbonates (especially calcium carbonate), bicarbonates, metal sulphides or sulphites. Use of the beads as packaging material is also claimed.

Description

(54) Title of the Invention: Packaging material

Abstract Title: Low density regenerated cellulose beads, manufacturing method, and use as packaging material (57) Low density regenerated cellulosic beads with a bulk density of below 450 g/l are claimed. A method of production requires mixing viscose with a salt that reacts with the acid regeneration bath to produce gas when placed in the regeneration bath, causing the bead to expand and become porous. Preferred salts are metal carbonates (especially calcium carbonate), bicarbonates, metal sulphides or sulphites. Use of the beads as packaging material is also claimed.

Figure 3

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Figure 1

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Figure 2

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Figure 3

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<%) euhw

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Size (μιτι)	Volume in %	Size (μιτι)	Volume in %	Size (μιτι)	Volume in %
0.010	0.00	1.096	0.00	120.226	0.00
0.011	0.00	1.259	0.00	138.038	0.00
0.013	0.00	1.445	0.00	158.489	0.00
0.015	0.00	1.660	0.00	181.970	0.00
0.017	0.00	1.905	0.00	208.930	0.00
0.020	0.00	2.188	0.00	239.883	0.00
0.023	0.00	2.512	0.00	275.423	0.00
0.026	0.00	2.884	0.00	316.228	0.00
0.030	0.00	3.311	0.00	363.078	0.00
0.035	0.00	3.802	0.00	416.869	0.06
0.040	0.00	4.365	0.00	478.630	0.85
0.046	0.00	5.012	0.00	549.541	3.80
0.052	0.00	5.754	0.00	630.957	9.97
0.060	0.00	6.607	0.00	724.436	18.06
0.069	0.00	7.586	0.00	831.764	24.43
0.079	0.00	8.710	0.00	954.993	24.51
0.091	0.00	10.000	0.00	1096.478	18.31
0.105	0.00	11.482	0.00	1258.925	0.00
0.120	0.00	13.183	0.00	1445.440	0.00
0.138	0.00	15.136	0.00	1659.587	0.00
0.158	0.00	17.378	0.00	1905.461	0.00
0.182	0.00	19.953	0.00	2187.762	0.00
0.209	0.00	22.909	0.00	2511.886	0.00
0.240	0.00	26.303	0.00	2884.032	0.00
0.275	0.00	30.200	0.00	3311.311	0.00
0.316	0.00	34.674	0.00	3801.894	0.00
0.363	0.00	39.811	0.00	4365.158	0.00
0.417	0.00	45.709	0.00	5011.872	0.00
0.479	0.00	52.481	0.00	5754.399	0.00
0.550	0.00	60.256	0.00	6606.934	0.00
0.631	0.00	69.183	0.00	7585.776	0.00
0.724	0.00	79.433	0.00	8709.636	0.00
0.832	0.00	91.201	0.00	10000.000	0.00
0.955	0.00	104.713	0.00
1.096	0.00	120.226	0.00

Figure 5

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Size (μιτι)	Volume in %	Size (μιτι)	Volume in %	Size (μιτι)	Volume in %
0.010	0.00	1.096	0.05	120.226	0.00
0.011	0.00	1.259	0.01	138.038	0.00
0.013	0.00	1.445	0.00	158.489	0.00
0.015	0.00	1.660	0.00	181.970	0.00
0.017	0.00	1.905	0.00	208.930	0.00
0.020	0.00	2.188	0.03	239.883	0.00
0.023	0.00	2.512	0.09	275.423	0.00
0.026	0.00	2.884	0.16	316.228	0.00
0.030	0.00	3.311	0.22	363.078	0.00
0.035	0.00	3.802	0.27	416.869	0.00
0.040	0.00	4.365	0.28	478.630	0.00
0.046	0.00	5.012	0.26	549.541	0.00
0.052	0.00	5.754	0.21	630.957	0.00
0.060	0.00	6.607	0.12	724.436	0.00
0.069	0.00	7.586	0.02	831.764	0.00
0.079	0.00	8.710	0.00	954.993	0.00
0.091	0.00	10.000	0.07	1096.478	0.00
0.105	0.00	11.482	0.32	1258.925	0.00
0.120	0.00	13.183	0.83	1445.440	0.00
0.138	0.00	15.136	1.72	1659.587	0.00
0.158	0.00	17.378	3.00	1905.461	0.00
0.182	0.00	19.953	4.66	2187.762	0.00
0.209	0.00	22.909	6.56	2511.886	0.00
0.240	0.00	26.303	8.49	2884.032	0.00
0.275	0.00	30.200	10.14	3311.311	0.00
0.316	0.00	34.674	11.23	3801.894	0.00
0.363	0.00	39.811	11.55	4365.158	0.00
0.417	0.00	45.709	10.99	5011.872	0.00
0.479	0.00	52.481	9.64	5754.399	0.00
0.550	0.07	60.256	7.73	6606.934	0.00
0.631	0.11	69.183	5.58	7585.776	0.00
0.724	0.13	79.433	3.49	8709.636	0.00
0.832	0.11	91.201	1.56	10000.000	0.00
0.955	0.08	104.713	0.24
1.096	0.05	120.226	0.00

Figure 7

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Figure 8

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Figure 9

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Figure 10

PACKAGING MATERIAL

FIELD [0001] Packaging materials in the form of low density cellulosic bead compositions and production methods are disclosed.

BACKGROUND [0002] Cellulose beads are spherical particles with diameters in the micro- to millimeter scale, which are used in many advanced applications ranging from chromatography over solidsupported synthesis and protein immobilization to retarded drug release. Over the last decades, various procedures for the preparation of cellulose beads have been reported, including the use of different solvents, shaping techniques, and technical devices for large batch production.

[0003] The preparation of spherical cellulose beads was described for the first time in

1951. The materials, then named cellulose pellets, were simply prepared by hand-dropping a viscose solution into an aqueous coagulation bath. Since that report, various procedures for obtaining cellulose beads with diameters ranging from about 10 pm to 1 - 3 mm have been developed using different solvents and techniques to obtain spherical particles. In principle, bead production can be simplified into three steps: (i) dissolution of cellulose (or a cellulose derivative), (ii) shaping of the polysaccharide solution into spherical particles, and (iii) sol - gel transition and solidification of the solution particles to beads. In addition, several post- and pretreatments can be applied to fine tune certain properties.

[0004] Various starting polysaccharides, solvents, and regeneration methods can be applied for the preparation of cellulose beads, yet all procedures have in common the fact that the shaping of the beads from a polysaccharide solution is either achieved by dropping or dispersion techniques.

[0005] In the dropping technique, beads can be obtained by the formation of spherical droplets of a polysaccharide solution and solidification of these droplets in a coagulation bath of a nonsolvent. Upon pressing the solutions through a thin opening, like a syringe nozzle, a droplet is formed when the combined forces of gravity and pressure used for ejection exceed a certain value that is determined by the surface tension of the solution and capillary forces at the outlet. The formation of smaller droplets can be forced by using vibrating nozzles or air jets, aimed at the tip of the capillary from which the solution protrudes. Different technical devices can be applied to obtain droplets of a defined size and shape. Other dropping techniques include Jet cutting, spinning drop atomization, and spinning disc atomization.

[0006] Dispersion of a solution of cellulose or a cellulose derivative in an immiscible solvent of opposite polarity under high rotational speed results in the formation of emulsions that can be stabilized with the aid of surfactants. These emulsions contain droplet particles of the dissolved polysaccharides that can be solidified to beads of the same size, as described below. The diameter of the droplets within the dispersion ranges from about 10 to several 100 pm and is determined by the mixing speed, type and amount of surfactant, ratio of hydrophobic to hydrophilic solvent, and viscosity of the dispersion medium and cellulose solution. Consequently, cellulose beads prepared by dispersion are roughly 10-times smaller compared to those prepared by dropping techniques. Further, dispersion techniques do not require special equipment to obtain products with reproducible properties.

[0007] The journal article “Preparation and characterization of crosslinked porous cellulose beads” by Bai et al., Carbohydrate Polymers 64 (2006) 402-407, discloses a method to prepare porous cellulose acetate beads. A cellulose diacetate is dissolved in dimethyl sulfoxide, to which sodium bicarbonate and anhydrous sodium sulfate are added and mixed. The mixture is added dropwise to an acid coagulation bath from a nozzle. Coagulated cellulose acetate beads were collected by filtration using a sieve. After the beads are filtered from the bath, hot water is used to dissolve and remove sodium sulfate.

[0008] Great Britain Patent No. 8,501,769 DO discloses a process for producing porous spherical cellulose acetate particles by adding acid to a coagulation bath where the particles may be used in packings. A dope solution comprising a modified cellulose acetate is added to an agitated coagulation bath of heated acetic acid solution. Beads are formed via the dispersion method. The instant application at least differs from the ‘769 in that carbonate is added to the dope (in this case viscose) and a drop method is used to produce beads.

[0009] U.S. Patent Publication No. 2016/0243521 A1 discloses a method for producing porous cellulose beads comprising the steps of preparing a cellulose dispersion by mixing cellulose with an alkaline solution, forming an emulsion and contacting the emulsion with a coagulating solvent.

[0010] U.S. Patent No. 6,106,763 A discloses a process for producing cellulosic moldings from cellulose, where the moldings can be food packaging in the form of beads. Beads are formed from a homogeneous alkaline solution that coagulates when introduced to an acid.

[0011] Great Britain Patent No. 2,152,936 B discloses a process for producing porous spherical cellulose acetate particles, where the particles may be used in packings. The particles are produced by adding a dope comprising a solution formed by dissolving a cellulose acetate in an acetic acid/ solution, and then feeding it into a heated acetic acid coagulation bath. Beads are formed by the dispersion technique.

[0012] U.S. Patent No. 2,543,928 A discloses a method of producing cellulose pellets comprising the steps of forming a solution of cellulose, passing drops of solution through a liquid that is inert to the cellulose solution and coagulating it in a coagulating bath, which may contain a salt solution.

[0013] U.S. Patent No. 7,052,775 B discloses a method of producing cellulosic formed particles in a precipitating bath with a coagulating agent.

[0014] European Patent No. 0,850,979 B discloses a method of manufacturing cellulose beads using a spinning vessel and the spinning drop atomization technique.

[0015] There is a continuing trend towards both recycling and composting of packaging materials. Certain types of packaging materials are required to offer a fully compostable solution. One example of this is where expanded polystyrene (EPS) beads are used to provide added protection during transit of packed goods. However, these beads are not considered biodegradable or home compostable, so where a home compostable or biodegradable solution is required currently only part of the package can be provided in that form. In many cases the EPS beads can form the majority of the pack, and as such present a significant problem to the shipping company.

[0016] A need was thus identified to produce a bead that can be classed as bio-based, biodegradable and home compostable.

[0017] Cellulose beads are known to be reproducible, but in general they are hard, inflexible and used for air filtration or aroma control etc. A method was required to make a low weight, flexible bead, with good resilience and conformability, to replicate the function of the EPS bead in packaging.

[0018] A wide range of experiments have been conducted to arrive at the present invention. The target has been to produce a low weight cellulose bead, with a good visual appearance, low residual odour, which is flexible and conformable, as close to the properties of EPS beads as possible.

SUMMARY [0019] The present invention provides regenerated cellulose beads having a bulk density below 450 g/L, for example having a bulk density within the range of approximately 75 g/L to approximately 450 g/L or within the range of approximately 150 to approximately 250 g/L.

[0020] Regenerated cellulose is a term of art which refers to a class of materials manufactured by the conversion of natural cellulose to a soluble cellulosic derivative and subsequent regeneration.

[0021] The beads may have a diameter size ranging between approximately 800 pm to approximately 6 mm, or from approximately 2 mm to approximately 3 mm.

[0022] Also provided are regenerated cellulose bead precursors comprising in droplet form a viscose solution and a salt. The salt composition may be selected from the group consisting of CaCO₃, Na₂CO₃, metal carbonates, bicarbonates, metal sulphides, and metal sulphites.

[0023] Regenerated cellulose bead precursors may also comprise in droplet form an otherwise aerated viscose solution.

[0024] Regenerated cellulosic beads of the invention may be provided by contacting the cellulosic bead precursors as described above with a viscose regeneration material. The viscose regeneration material may comprise an acid.

[0025] The beads can be produced from a mixture comprising a salt composition and a viscose composition, wherein the salt composition produces a gas when added to a regeneration bath, and the viscose composition has a Hottenroth number within the range of approximately 4 to approximately 17. Alternatively, the Hottenroth number may be from 5 to 15, from 6 to 14, from 7 to 13, from 8 to 10, or approximately 8.5.

[0026] The pre-dried regenerated cellulose bead may include from 5 to 50%, from 10 to 40% or from 15 to 35% by weight cellulose, and from approximately 1 to 30%, 5 to 25% or 10 to 25% by weight softeners. Softeners may be selected from the group consisting of glycerine, PEG, MPG, and TEG. The term “pre-dried bead” refers to the bead once it is formed but before any drying process occurs. The remainder of the weight may comprise water.

[0027] The viscose and salt mixture may comprise 3 to 10% cellulose, from 1 to 7%

NaOH and from 2 to 7% calcium carbonate by weight.

[0028] The present invention discloses a method of forming a regenerated cellulosic bead comprising: mixing a viscose composition with water and a salt composition; creating one or more droplets from the mixture; and contacting the droplets with regeneration bath such that gas is generated from reaction of the salt composition with the regeneration bath, and thereby forming a porous internal structure within the bead.

[0029] The present invention also provides a method of forming a regenerated cellulosic bead wherein air is included when mixing the viscose with water and salt composition.

[0030] The present invention also provides a method of forming a cellulosic regenerated bead wherein the mixing further comprises including softeners and functional additives.

[0031] The present invention also provides a method of forming a regenerated cellulosic bead wherein the softeners are comprised of glycerine, PEG, MPG, or TEG.

[0032] The present invention also provides a method of forming a regenerated cellulosic bead wherein the functional additives are comprised of starch, chitosan, pigments, waxes, hydrophobizing agents, gelatine, or dyes.

[0033] The present invention also provides a method of forming a regenerated cellulosic bead wherein creating droplets from the mixture is performed using a bead forming dye.

[0034] The present invention also provides a method of forming a regenerated cellulosic bead wherein the dye is a hypodermic needle with a tapered end.

[0035] The present invention also provides a method of forming a regenerated cellulosic bead wherein the dye is at least 5 cm above the regeneration bath.

[0036] The present invention also provides a method of forming a regenerated cellulosic bead wherein suitable pressure is maintained such that the viscose mixture is pushed through the dye and individual droplets are formed, rather than a continuous stream of viscose. In this case, a suitable pressure is one that forms consistent droplets from the needle head. A suitable pressure will depend on the viscosity of the solution and the gauge needle used. We found a suitable pressure includes the range of 0.05 bar to 4 bar.

[0037] The present invention also provides a method of forming a regenerated cellulosic bead wherein the bead is approximately 800 pm to approximately 6 mm in diameter.

[0038] The present invention also provides a method of forming a regenerated cellulosic bead wherein the method terminates with an additional processing step comprising: washing the beads with water, followed by washing the beads with NaOH, followed by washing the beads with sodium hypochlorite (bleach), and then washing the beads with water, then optionally adding softeners or functional additives, and then drying the beads.

[0039] The present invention also provides a regenerated cellulose bead composition produced by any combination of the methods described herein.

[0040] The present invention also provides a regenerated cellulose bead having a bulk density of less than or equal to approximately 425 g/Litre.

BRIEF DESCRIPTION OF THE DRAWINGS [0041] The above-mentioned and other features of this disclosure, and the manner of attaining them, will become more apparent and the disclosure itself will be better understood by reference to the following description of embodiments ofthe disclosure taken in conjunction with the accompanying drawings, wherein:

[0042] Figure 1: Beads produced with simple water washing (left) and washing regime described herein (right).

[0043] Figure 2: Pressurised vessel fitted with a needle.

[0044] Figure 3: A cross section of a stained bead produced using CaCO₃ as described in Example 1.

[0045] Figure 4: Particle size distribution of the microbeads produced in Example 2.

[0046] Figure 5: Particle size distribution data of the microbeads produced in Example

2.

[0047] Figure 6: Particle size distribution of CaCO₃ in solution as described in step 1 of Example 1.

[0048] Figure 7: Particle size distribution data of CaCO₃ in solution as described in step 1 of Example 1.

[0049] Figure 8: A cross section of a bead produced by the method as described in

Example 4.

[0050] Figure 9: A cross section of a bead produced by the method as described in

Example 6.

[0051] Figure 10: A cross section of an example of a bead made without the addition of carbonate and using low Hottenroth viscose.

[0052] Although the drawings represent embodiments of the present disclosure, the drawings are not necessarily to scale and certain features may be exaggerated in order to better illustrate and explain the present disclosure.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS [0053] The embodiments disclosed below are not intended to be exhaustive or limit the disclosure to the precise forms disclosed in the following detailed description. Rather, the embodiments are chosen and described so that others skilled in the art may utilize their teachings.

[0054] A viscose composition, containing from 1 to 12% cellulose and from 1 to 10% sodium hydroxide, having a Hottenroth number within the range of approximately 4 to approximately 17 may be mixed with water, and a salt composition, such as calcium carbonate or sodium carbonate, and mixed fully. The Hottenroth number is the amount of sodium chloride or ammonium chloride solution needed to coagulate the viscose. Air can be included at this stage to further decrease the final density ofthe bead. Preferably small air bubbles are created otherwise the final bead can be too soft and is irreversibly crushed under compression. The desirable final bead has a level of resilience, and will reform after compression. To generate a final bead with additional air bubbles, higher Hottenroth viscose (>8.5) may be used, thereby allowing very small air bubbles to be derived in the bead from the release of some excess CS₂and H₂S during regeneration. This effect is known as “diffusion”, and for film formation is not a desirable feature. However, it was discovered to be a useful facet for bead formation.

[0055] At this stage, other functional additives such as starch, chitosan, pigments etc.

can be added to the viscose to change the final properties of the bead.

[0056] The viscose is loaded into a suitable chamber or pumped directly to a bead forming dye. The dye may comprise a cylindrical tube of a narrow aperture suspended above the regeneration bath.

[0057] It was found that the design of the bead forming dye, the size, the height above the regeneration bath, the pressure used and the shape ofthe dye end all impact on the final bead shape, size and uniformity.

[0058] In the laboratory, it has been found that a hypodermic needle with a tapered end gave the best performance, as this allowed good bead formation and reduced the propensity to produce a “tail” on the bead by reducing the final contact area between the needle end and the viscose. For example, the HSW-FineJect needles from Henke Saas Wolf may be used.

[0059] Increasing the gap between the dye head and the regeneration bath also reduces the propensity for tail formation. A gap of at least 5 cm is preferable, preferably between 5 and 15cm.

[0060] The viscose is forced through the dye head at a pressure such that the viscose can form individual droplets rather than forming a continuous stream of viscose. The required pressure changes depending on the formulation. For an up-scaled process, a large number of dye heads can be used to make the process commercially viable.

[0061] The “gauge” of the needle used alters the aperture size, which directly impacts on the final bead size. Using this technique, beads can be produced in sizes ranging between approximately 800 pm to approximately 6 mm in diameter.

[0062] The viscose bead can drop into a regeneration bath which contains either an acid or salt of suitable concentration to allow the cellulose to precipitate quickly into its bead shape. A mixture of both an acid and a salt may be used, preferably sulphuric acid and sodium sulphate.

[0063] Heating of this regeneration liquid may aid the formation of the bead by speeding up the regeneration process. The bath may be heated to above 50°C, preferably above 60°C. Ideally the regeneration liquid/bath is stirred, which may promote a vortex in the bath so that the beads are pulled under the liquid surface. This promotes complete regeneration of the viscose across the full surface of the bead and prevents agglomeration of the beads.

[0064] The salt composition reacts with the acid regeneration bath to produce gas when placed in the regeneration bath. Salts that produce gas in the acid regeneration bath include metal carbonates (i.e. CaCO₃ and Na₂CO₃), bicarbonates, metal sulphides, and metal sulphites.

[0065] The carbonate used in the viscose formulation reacts with the acid to create carbon dioxide gases within the structure of the bead, creating a porous and cavitated internal structure, such as voids or cavities in the internal structure. This porous and cavitated internal structure reduces the final density of the bead thus increasing the flexibility and resilience of the final bead. A cross section of an example of a bead made without the addition of carbonate and using low Hottenroth viscose (~8) can be seen in Fig. 10.

[0066] The regenerated beads can then be processed to render them in a usable format. The processing can include a washing regime comprised of removing the beads from the regeneration bath after such time that they are completely regenerated and washing them using a combination of hot and cold water wash baths, followed by a 0.4% sodium hydroxide bath, then a 0.35% bleach (sodium hypochlorite) bath, finished with additional water wash baths. The bead can also be passed through a final bath to add any additional additives to the bead to change the final properties.

[0067] This washing regime enables a pure white clean and aroma free bead to be produced compared to just simple water washing (shown in Fig. 1).

[0068] These materials would include a range of “softeners” such as glycerine, PEG,

MPG, TEG, etc. or other functional additives such as waxes, hydrophobizing agents, gelatine, starches, dyes etc.

[0069] Finally, the beads need to be dried to remove an excess water. The dry point is determined by the point at which no excess water can be squeezed out of the bead under compression.

[0070] Due to the high internal surface area of the bead, it was found that the beads can contain a significant amount of water, without appearing to be physically wet.

[0071] The invention is further demonstrated by the following examples, which are not intended to be limiting to the scope of the invention.

[0072] Example 1 - Ideal packaging Beads [0073] Example 1 uses calcium carbonate as the selected salt to generate gas in the regeneration bath.

[0074] The most suitable formulation and process found to date to produce a 2-3 mm

EPS style bead is as follows:

[0075] 1. 13.8 g of calcium carbonate was mixed using a high shear “Silverson” mixer in 100 g of water, to give a dispersion of CaCO₃ with an average particle size of 35 pm in the water. The PSD data can be seen in Fig. 6 & Fig. 7.

[0076] 2. The carbonate and water mixture was added to 200 g of Viscose with a

Hottenroth of 10.5 (ml of 10% ammonium chloride) and 2 g of disperbyk-190 surfactant, using an overhead saw-tooth mixer to achieve a homogeneous mixture.

[0077] 2a. This means the final viscose, carbonate and water mixture composition contained ~5.7% cellulose (by weight), 3.8% sodium hydroxide (by weight) and 4.4% calcium carbonate (by weight). This formulation has a high calcium carbonate to cellulose ratio, which is useful for deriving the lower density bead.

[0078] 3. The viscose was placed in a pressurised vessel which was fitted with a gauge needle, having an internal diameter of 1.067 mm (assembly shown in Fig. 2).

[0079] 3a. The needle head was set 14 cm above the acid level and the acid was heated to 60 °C and a magnetic flea added to stir the acid to create a vortex that could submerge the beads during regeneration.

[0080] 3b. The final bead being 2-3 mm demonstrates a significant increase in the bead volume driven by the gassing created during regeneration.

[0081] 4. The beads were washed and treated as described in the washing regime above and softened with a solution containing 20% glycerine.

[0082] 5. The beads were dried in a rotary drier at 60 °C for 12 hrs until reaching the dry point when no excess water can be squeezed out of the bead under compression.

[0083] 6. The beads were tested for composition and found to be approximately

25% cellulose (by weight), 13% glycerine (by weight) and 62% water (by weight). The beads had an average size of 2-3 mm. The final bead was found to have a bulk density of 190 g/L.

[0084] 7 A cross section of a stained bead, demonstrating the internal structure, is shown in Fig. 3. The dark areas are cellulose and the clear areas are the air filled cavities within the bead.

[0085] Example 2 - Microbeads [0086] 1. 100 g of viscose with a Hottenroth of 10.5 (ml of 10% ammonium chloride) and 100 g of water was mixed by hand.

[0087] 2. The viscose was placed in a pressurised vessel which was fitted with a gauge needle, having an internal diameter of 0.603 mm (assembly shown in Fig. 2).

[0088] 3. The needle head was set 14 cm above the acid level and the acid was heated to 60 °C and a magnetic flea added to stir the acid to create a vortex that could submerge the beads during regeneration.

[0089] 4. The beads were washed and treated as described in the washing regime above, but not softened due to the final bead achieved being a lot harder.

[0090] 5. The beads were then transferred to a wire tray and dried in an oven at °C for 3 hrs.

[0091] 6. Particle size analysis of the beads was conducted using a Malvern 2000

MU mastersizer unit, with the beads dispersed in water, the PSD is shown in Fig. 4. and Fig.

5. The average particle size was found to be 239 pm.

[0092] Example 3 - Extremely low density bead [0093] 1. 200 g of viscose with a Hottenroth of 8.0 (ml of 10% ammonium chloride), 98 g of water and 2 g of disperbyk-190 surfactant was mixed using a standard kitchen balloon whisk (Kitchen Aid) for 3 mins.

[0094] 2. The viscose solution was then drawn up into a 10 mL plastic syringe, fitted with a 23 gauge needle, having an internal diameter of 0.337 mm.

[0095] 3. The viscose was then slowly drip feed into the acid which was heated to °C and a magnetic flea added to stir the acid to create a vortex that could submerge the beads during regeneration.

[0096] 4. The beads were washed and treated as described in the washing regime above, but not softened due to the final bead achieved being a lot harder.

[0097] 5. The beads were then transferred to a wire tray and dried in an oven at °C for 3 hrs.

[0098] 6. The final bead had a density of 90 g/L.

[0099] Example 4 - Alterative low density bead formulation I [00100] Example 4 uses calcium carbonate as the salt to generate gas in the regeneration bath.

[00101] 1 9.2 g of calcium carbonate was mixed using a high shear “Silverson” mixer in 50 g of water.

[00102] 2. The carbonate and water mixture was added to 100 g of viscose with a

Hottenroth of 10.5 (ml of 10% ammonium chloride) using an overhead saw-tooth mixer to achieve a homogeneous mixture.

[00103] 3. The viscose, carbonate and water mixture was placed in a pressurised vessel which was fitted with a 20 gauge needle, having an internal diameter of 0.603 mm (assembly shown in Fig. 2).

[00104] 3a. The needle head was set 14 cm above the acid level and the acid was heated to 60 °C and a magnetic flea added to stir the acid to create a vortex that could submerge the beads during regeneration.

[00105] 3b. The final bead size was 2-3 mm, which demonstrates a significant increase in the bead volume driven by the gassing created during regeneration.

[00106] 4. The beads were washed and treated as described in the washing regime above and softened with a solution containing 20% glycerine.

[00107] 5. The beads were dried in a rotary drier at 60 °C for 12 hrs until reaching the dry point when no excess water can be squeezed out of the bead under compression. The final bead had a density of 311 g/Litre.

[00108] 6 A cross section of the beads can be seen in Fig. 8.

[00109] Example 5 - Alterative low density bead formulation II [00110] Example 5 uses calcium carbonate as the selected salt to generate gas in the regeneration bath.

[00111] 1 5 g of calcium carbonate was mixed using a high shear “Silverson” mixer in 50 g of water.

[00112] 2. The carbonate and water mixture was added to 150 g of viscose with a

Hottenroth of 10.5 (ml of 10% ammonium chloride) and 2 g of oil, using an overhead saw-tooth mixer to achieve a homogeneous mixture.

[00113] 3. The viscose, carbonate and water mixture was placed in a pressurised vessel which was fitted with a 15 gauge needle, having an internal diameter of 1.372 mm (assembly shown in Fig. 2).

[00114] 3a. The needle head was set 14 cm above the acid level and the acid was heated to 60 °C and a magnetic flea added to stir the acid to create a vortex that could submerge the beads during regeneration.

[00115] 4. The beads were washed and treated as described in the washing regime above and softened with a solution containing 20% glycerine.

[00116] 5. The beads were dried in a rotary drier at 60 °C for 12 hrs until reaching the dry point when no excess water can be squeezed out of the bead under compression. The final bead had a density of 425 g/Litre.

[00117] Example 6 - White Bead [00118] Example 6 uses calcium carbonate as the selected salt to generate gas in the regeneration bath. The TiO₂ is used to color the bead and CaCO₃ is used to create the porosity.

[00119] 1. 4.6g of TiO₂ and 4.6g of calcium carbonate was mixed using a high shear “Silverson” mixer in 50g of water.

[00120] 2. The TiO₂ and water mixture was added to 100 g of viscose with a

Hottenroth of 10.5 (ml of 10% ammonium chloride), using an overhead saw-tooth mixer to achieve a homogeneous mixture.

[00121] 3. The viscose, TiO₂ and water mixture was placed in a pressurised vessel which was fitted with a 15 gauge needle, having an internal diameter of 1.372 mm (assembly shown in Fig. 2).

[00122] 3a. The needle head was set 14 cm above the acid level and the acid was heated to 60 °C and a magnetic flea added to stir the acid to create a vortex that could submerge the beads during regeneration.

[00123] 4. The beads were washed and treated as described in the washing regime above and softened with a solution containing 20% glycerine.

[00124] 5. The beads were dried in a rotary drier at 60 °C for 12 hrs until reaching the dry point when no excess water can be squeezed out of the bead under compression.

[00125] 6 A cross section of the beads can be seen in Fig. 9.

[00126] While this disclosure has been described as having an exemplary design, the present disclosure may be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the disclosure using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this disclosure pertains.

Claims

What is claimed is:

1. Regenerated cellulose beads having a bulk density below 450 g/L.

2. The beads of claim 1 having a bulk density within the range of approximately 75 g/L to approximately 450 g/L.

3. The beads of claim 2 having a bulk density within the range of approximately 150 to approximately 250 g/L.

4. The beads of any one of claims 1 to 3 having a diameter size ranging between approximately 800 pm to approximately 6 mm.

5. The beads of claim 4 having an average diameter size ranging between approximately 2 mm to approximately 3 mm.

6. Regenerated cellulose bead precursors comprising in droplet form a viscose solution and a salt.

7. Bead precursors of claim 6 wherein the salt composition is selected from the group consisting of CaCO3, Na2CO3, metal carbonates, bicarbonates, metal sulphides, and metal sulphites.

8. Bead precursors according to claim 6 wherein the salt is a carbonate.

9. Regenerated cellulose bead precursors comprising in droplet form aerated viscose solution.

10. A method for forming the regenerated cellulosic beads of any one of claims 1 to 5 comprising contacting the cellulosic bead precursors of any one of claims 6 to 9 with a viscose regeneration material.

11. The method of claim 10 wherein the viscose regeneration material comprises an acid.

12. The beads of any one of claims 1 to 5, produced from a mixture comprising a salt composition and a viscose composition, wherein the salt composition produces a gas when added to a regeneration bath, and the viscose composition has a Hottenroth number within the range of approximately 4 to approximately 17.

13. The beads of claim 12 wherein the viscose composition has a Hottenroth number of from 5 to 15, from 6 to 14, from 7 to 13, from 8 to 10, or approximately 8.5.

14. The beads of claim 12 or 13 wherein the pre-dried beads include from 5 to 50%, from 10 to 40% or from 15 to 35% by weight cellulose, and from approximately 1 to 30%, 5 to 25% or 10 to 25% by weight softeners, the remainder of the weight consisting of water.

15. The beads of claim 14 wherein the softeners are selected from the group consisting of glycerine, PEG, MPG, and TEG.

16. The beads of any one of claims 12 to 15 wherein the mixture comprising salt composition and a viscose composition includes 3 to 10% cellulose, from 1 to 7% NaOH and from 2 to 7% calcium carbonate by weight.

17. A method of forming a regenerated cellulosic bead comprising: mixing a viscose composition with water and a salt composition; creating one or more droplets from the mixture; and contacting the droplets with regeneration bath, such that gas is generated from reaction of the salt composition with the regeneration bath, thereby forming a porous internal structure within the bead.

18. The method of claim 17 wherein air is included with the mixing.

19. The method of claim 17 or 18 wherein the step of mixing further comprises the addition of softeners or functional additives.

20. The method of claim 19 wherein the softeners are selected from the group consisting of glycerine, PEG, MPG, and TEG.

21. The method of claim 20 wherein the functional additives are selected from the group consisting of starch, chitosan, pigments, waxes, hydrophobizing agents, gelatine, and dyes.

22. The method of any one of claims 17 to 21 wherein the step of creating droplets from the mixture is performed using a bead forming dye.

23. The method of claim 22 wherein the dye is a hypodermic needle with a tapered end.

24. The method of claim 22 or 23 wherein the dye is at least 5 cm above the regeneration bath.

25. The method of any one of claims 17 to 24 followed by an additional processing step comprising:

washing the beads with water, followed by NaOH, followed by bleach, and then water; and optionally adding softeners or functional additives; and drying the beads.

26. Regenerated cellulose beads produced by the method of any one of claims 10, 11 or 17 to 25.

27. A compostable packaging material comprising the regenerated cellulosic beads of any one of claims 1 to 5, 12 to 16 or 26.

Intellectual

Property

Office

Application No: GB1704850.5 Examiner: Mr Jason Scott