Polymer foams, methods and related uses - Patents.com

Abstract

The present disclosure relates to a polymer foam comprising cellulose acetate propionate, a second polymer selected from a group of polymers, and at least one nucleating agent, the foam being produced by using at least one blowing agent, and further relates to articles, methods and uses.

Description

[Technical field]

[0001] The present disclosure relates to polymeric foams and their manufacture. In particular, polymeric foams are described that include cellulose acetate propionate (CAP), a second polymer, a nucleating agent, and a blowing agent. [Background technology]

[0002] Polymer foams, also known as expandable plastics, are materials made by combining a solid phase with a gas phase. Polymer foams are attractive due to their low density, good thermal insulation, good sound insulation and high strength-to-weight ratio.

[0003] Polymer foams are typically produced by a variety of foaming processes, including extrusion foaming, particle bead foaming, autoclave foaming, and foam injection molding. Various types of polymers are expanded into porous or foamed materials by using blowing agents.

[0004] Polymer foams have many applications, most importantly in packaging, acoustics, insulation, automotive, sporting goods, lightweight parts and construction. Summary of the Invention

[0005] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

[0006] The present disclosure relates to a polymer foam, the polymer foam material comprising: Cellulose acetate propionate (CAP), a second polymer selected from an aliphatic or aliphatic-aromatic polyester, an aliphatic or aliphatic-aromatic copolyester, or a polylactide; at least one nucleating agent, The polymer foam is produced by using at least one blowing agent.

[0007] A method for producing a polymer foam is also disclosed, the method comprising: providing a second polymer selected from cellulose acetate propionate (CAP), an aliphatic or aliphatic-aromatic polyester, or an aliphatic or aliphatic-aromatic copolyester, or a polylactide; mixing said cellulose acetate propionate (CAP) and said second polymer with at least one blowing agent and at least one nucleating agent to obtain a polymer mixture; forming the polymer mixture into a polymer foam by using a foam-producing method to obtain a polymer foam.

[0008] The present disclosure also describes articles and uses related to the disclosed polymer foams.

[0009] The accompanying drawings, which are included to provide a further understanding of the embodiments and are incorporated in and constitute a part of this specification, illustrate embodiments. [Brief description of the drawings]

[0010] [Figure 1] 4 shows a scanning electron microscopy examination of polymer foam sample 1, reference example 4. [Diagram 2] 4 shows a scanning electron microscopy examination of polymer foam sample 1, reference example 4. [Diagram 3] 5 shows a scanning electron microscopy examination of Reference Example 5, polymer foam sample 2. [Figure 4] 5 shows a scanning electron microscopy examination of Reference Example 5, polymer foam sample 2. [Diagram 5] 5 shows a scanning electron microscopy examination of Reference Example 5, polymer foam sample 3. [Figure 6]5 shows a scanning electron microscopy examination of Reference Example 5, polymer foam sample 3. [Figure 7] 5 shows a scanning electron microscopy examination of Reference Example 5, polymer foam sample 4. [Figure 8] 5 shows a scanning electron microscopy examination of Reference Example 5, polymer foam sample 4. [Figure 9] 5 shows a scanning electron microscopy examination of Reference Example 5, polymer foam sample 5. [Figure 10] 5 shows a scanning electron microscopy examination of Reference Example 5, polymer foam sample 5. [Figure 11] 5 shows a scanning electron microscopy examination of Reference Example 5, polymer foam sample 6. [Figure 12] 5 shows a scanning electron microscopy examination of Reference Example 5, polymer foam sample 6. [Figure 13] 5 shows a scanning electron microscopy examination of Reference Example 5, polymer foam sample 7. [Figure 14] 5 shows a scanning electron microscopy examination of Reference Example 5, polymer foam sample 7. [Figure 15] 5 shows a scanning electron microscopy examination of Reference Example 5, polymer foam sample 8. [Figure 16] 5 shows a scanning electron microscopy examination of Reference Example 5, polymer foam sample 8. [Figure 17] 5 shows a scanning electron microscopy examination of Reference Example 5, polymer foam sample 9. [Figure 18] 5 shows a scanning electron microscopy examination of Reference Example 5, polymer foam sample 9. [Figure 19] Reference Example 5 shows a scanning electron microscopy examination of polymer foam sample 10. [Figure 20] Reference Example 5 shows a scanning electron microscopy examination of polymer foam sample 10. [Figure 21] 5 shows a scanning electron microscopy examination of Reference Example 5, polymer foam sample 11. [Figure 22] 5 shows a scanning electron microscopy examination of Reference Example 5, polymer foam sample 11. [Diagram 23]5 shows a scanning electron microscopy examination of Reference Example 5, polymer foam sample 12. [Figure 24] 5 shows a scanning electron microscopy examination of Reference Example 5, polymer foam sample 12. [Diagram 25] 5 shows a scanning electron microscopy examination of Reference Example 5, polymer foam sample 13. [Figure 26] 5 shows a scanning electron microscopy examination of Reference Example 5, polymer foam sample 13. [Figure 27] 5 shows a scanning electron microscopy examination of Reference Example 5, polymer foam sample 14. [Figure 28] 5 shows a scanning electron microscopy examination of Reference Example 5, polymer foam sample 14. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Polymer foams, also known as expandable plastics, are important products for the plastics industry and consumers. Currently, the plastics most used in polymer foams are polyurethane, polystyrene, polyethylene, and polyvinyl chloride. These products are considered environmentally unfriendly, typically due to their low renewable content and high carbon footprint. In addition, it is considered difficult to recycle many of these plastics commonly used in foam applications.

[0012] The present disclosure describes a novel polymer foam. The present disclosure is based on the finding that high quality polymer foam can be obtained using a polymer blend containing at least two polymers. The present disclosure can provide a polymer foam based on renewable materials, which can be used to manufacture various articles for industrial and consumer use. The polymer foam disclosed herein, and the articles produced therefrom, can replace foams based on pure fossil raw materials. Thus, the polymer foam of the present disclosure, and the articles produced therefrom, provide a more sustainable material option for the plastics industry and consumers.

[0013] The present disclosure relates to a polymer foam, the polymer foam material comprising: Cellulose acetate propionate (CAP), a second polymer selected from an aliphatic or aliphatic-aromatic polyester, an aliphatic or aliphatic-aromatic copolyester, or a polylactide; at least one nucleating agent, The polymer foam is produced by using at least one blowing agent.

[0014] A method for producing a polymer foam is also disclosed, the method comprising: providing a second polymer selected from cellulose acetate propionate (CAP), an aliphatic or aliphatic-aromatic polyester, or an aliphatic or aliphatic-aromatic copolyester, or a polylactide; mixing said cellulose acetate propionate (CAP) and said second polymer with at least one blowing agent and at least one nucleating agent to obtain a polymer mixture; forming the polymer mixture into a polymer foam by using a foam-producing method to obtain a polymer foam.

[0015] There are several methods for producing polymer foams. Typically, the process steps include the introduction of a blowing agent into the polymer, initial cell formation by nucleation, cell growth of the nucleated cells, and stabilization of the expanded cells.

[0016] Polymer foams are typically produced such that the foaming temperature is below or close to the transition temperature of the polymer used. This is due to the fact that the blowing agent acts as a plasticizer. The reduction in temperature is also essential to reduce the polymer viscosity and effectively stabilize the foam structure. In addition, since the blowing agent, such as CO2, must diffuse out of the polymer foam structure and be exchanged with air even when the polymer foam is still cooling, the unstable polymer foam easily collapses under the pressure created by the diffusion.

[0017] The present disclosure describes polymer foams made with a polymer blend comprising at least two polymers, and in addition, at least one nucleating agent and at least one blowing agent are used in the production of the polymer foam. The two polymers used may have distinct melting points and glass transition temperatures.

[0018] In general, when two polymers are used in a polymer foam, and when the melting points and glass transition temperatures are significantly different, it can be difficult to obtain a high-quality polymer foam. If the melting point of the second polymer is significantly lower than the foaming temperature, the polymer with the lower melting point is expected to collapse during foam formation, cooling, and diffusion of the blowing agent. This phenomenon is expected to occur when a large amount of the second polymer is used.

[0019] The inventors have found that when using cellulose acetate propionate (CAP) and, for example, polybutylene succinate (PBS) as the polymers in the polymer foam, high quality foams were obtained even when the melting points of the two polymers differed significantly. The two polymers shown in the examples may have distinctly different melting points and glass transition temperatures. Since the melting point of the CAP polymer is 188-210°C, the melting point of the PBS polymer is 115°C, and the foaming temperature of the polymer foam samples is 155°C-195°C, the polymer with the lower melting point is expected to collapse during foam formation, cooling, and CO2 diffusion.

[0020] Thus, it is surprising that the polymer blends shown in the examples, having up to 30% by weight of PBS polymer, can form stable polymer foams with stable foam structure and low density, the cure of which is achieved as a combination of blowing and nucleating agents.

[0021] It is expected that polymers with similar chemical structure, melting point or glass transition temperature can produce similar results as the above specific embodiment shown by example. The second polymer can be an aliphatic polyester or copolyester. The second polymer can also be an aliphatic-aromatic polyester or copolyester. The second polymer can also be a polylactide.

[0022] The polymeric foams described herein include at least two polymers: a first polymer is cellulose acetate propionate (CAP) and a second polymer is selected from an aliphatic or aliphatic-aromatic polyester, an aliphatic or aliphatic-aromatic copolyester, or a polylactide.

[0023] According to one embodiment, the polymer foam comprises a combination of cellulose acetate propionate (CAP) and the second polymer in an amount of at least 80% by weight, or at least 85% by weight, or at least 90% by weight, or at least 95% by weight, based on the total weight of the polymer foam.

[0024] The polymeric foam may also include a combination of cellulose acetate propionate (CAP) and the second polymer in an amount of at least 70% by weight, or at least 75% by weight, based on the total weight of the polymeric foam.

[0025] In a polymer blend, the CAP and the second polymer may be present in different amounts.

[0026] According to one embodiment, the polymer foam comprises CAP in an amount of 30-95 wt%, or 40-95 wt%, or 50-90 wt%, or 55-90 wt%, or 60-90 wt%, or 70-90 wt%, and said second polymer in an amount of 5-70 wt%, or 5-60 wt%, or 10-50 wt%, or 10-45 wt%, or 10-40 wt%, or 10-30 wt%, based on the total weight of the polymer foam.

[0027] The polymer foam also comprises the CAP in an amount of 50-95 wt%, or 55-95 wt%, or 60-95 wt%, or 65-95 wt%, or 70-95 wt%, or 75-95 wt%, or 80-95 wt%, and the second polymer in an amount of 5-50 wt%, or 5-45 wt%, or 5-40 wt%, or 5-35 wt%, or 5-30 wt%, or 5-25 wt%, or 5-20 wt%, based on the total weight of the polymer foam.

[0028] According to one embodiment, the polymer foam comprises a second polymer selected from an aliphatic or aliphatic-aromatic polyester, an aliphatic or aliphatic-aromatic copolyester, and a polylactide.

[0029] The second polymer can be a polyester or polylactide with a relatively low melting point and a relatively low glass transition temperature. In the examples, this type of polymer has been shown to result in high quality polymer foams, despite the large differences in melting and glass transition temperatures of the second polymer and cellulose acetate propionate.

[0030] According to one embodiment, the polymer foam comprises the second polymer selected from the group consisting of polypropylene succinate (PPS), polybutylene succinate (PBS), polybutylene succinate adipate (PBSA), polybutylene adipate terephthalate (PBAT), polybutylene adipate (PBA), polycaprolactone (PCL), polyhydroxyalkanoate (PHA), and polybutylene sebacate (PBSE), or combinations thereof.

[0031] According to one embodiment, the polymer foam comprises said second polymer having a melting point of 180° C. or less, or 170° C. or less, or 160° C. or less, or 150° C. or less. According to one particular embodiment, the polymer foam comprises said second polymer having a melting point of 140° C. or less, or 130° C. or less, or 120° C. or less. The melting point of the second polymer may for example be 110° C., or 115° C., or 120° C. According to one very particular embodiment, the melting point is between 60° C. and 180° C., or between 80° C. and 170° C.

[0032] According to one embodiment, the polymer foam comprises said second polymer having a glass transition temperature (Tg) of 20° C. or less, or 10° C. or less, or 0° C. or less, or -10° C. or less, or -20° C. or less, or -25° C. or less. The glass transition temperature of the second polymer may for example be -28° C., or -32° C., or -35° C. According to one very particular embodiment, the glass transition temperature of the second polymer is between -40° C. and 20° C., or between -20° C. and 10° C.

[0033] According to one particular embodiment, the polymer foam comprises said second polymer being polybutylene succinate (PBS).

[0034] Additionally, the second polymer may be a polyester or polylactide with a relatively high melting point and a relatively high glass transition temperature. These polyesters and polylactides are also expected to produce high quality foams. Stable polymer foams are expected because the melting points and glass transition temperatures of these polyesters and polylactides are close to those of the cellulose acetate propionate polymer.

[0035] According to one embodiment, the polymer foam comprises the second polymer selected from the group consisting of polylactic acid (PLA), polyethylene furanoate (PEF), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), and polyglycolic acid (PGA), or combinations thereof.

[0036] According to one embodiment, the polymer foam comprises said second polymer having a melting point of 300°C or less, or 270°C or less, or 265°C or less.

[0037] According to one embodiment, the polymer foam comprises the second polymer having a glass transition temperature (Tg) of 100° C. or less, or 90° C. or less, or 85° C. or less.

[0038] According to one embodiment, the polymer foam comprises the second polymer, which is produced completely or partially by a bioprocess, such as a fermentation process. According to one embodiment, the second polymer has a residual nitrogen content of 0.01 to 1000 ppm.

[0039] Suitably, when CAP is used, the number average molar mass of the CAP polymer is greater than 20,000 Da. According to one embodiment, the number average molar mass is between 30,000 and 110,000 Da, typically between 50,000 and 100,000 Da, or between 65,000 and 95,000 Da. The number average molar mass may be between 85,000 and 95,000 Da, or between 85,000 and 91,000 Da, for example, 90,000 Da, 91,000 Da, or 92,000 Da. A number average molar mass within the above defined range may provide an elastic material with mechanical properties for producing a polymer foam.

[0040] The number average molar mass measurements carried out in connection with this disclosure were measured using size exclusion chromatography (SEC) using chloroform eluent for number average molar mass measurements. SEC measurements were carried out using three columns including Styragel HR 4 and a precolumn, with chloroform eluent (0.6 mL / min, T=30° C.). Elution curves were detected using a Waters 2414 refractive index detector. Molar mass distributions were calculated against a 10×PS (580-3040000 g / mol) standard using Waters Empower 3 software.

[0041] Various grades of cellulose esters, such as cellulose acetate propionate, are commercially available from several suppliers. In the disclosed polymer foams, the polymer raw materials affect the properties of the mixture formed. In other words, the properties of the combined polymers need to be evaluated when forming the polymer blend for the polymer foam. For example, if the number average molar mass of one of the polymers is high, such as 90,000 Da or 70,000 Da, it may be suitable to combine this polymer with another polymer with a lower number average molar mass. Alternatively, or in addition, for example, a softener may be used with the polymer with a higher molar mass. The suitable number average molar mass varies depending on the end use of the foam. That is, the most suitable grade of cellulose ester may differ depending on the intended end use. The cellulose ester may have different degrees of substitution. CAPs suitable for the polymer foams preferably have an acetyl content of 0-40% by weight, or 0.5-30% by weight, or 0.5-25% by weight, or 0.5-15% by weight, or 0.5-5.0% by weight, or 0.8-2.0% by weight. Typically, it is 1.0-1.5% by weight, for example 1.3% by weight. CAPs suitable for the described polymer foams preferably have a propionyl content of 5-51% by weight, or 15-51% by weight, or 30-51% by weight. It may also be, for example, 18% by weight, or 20% by weight, or 25% by weight. Typically, it may be 40-50% by weight. A very particular example is 48% by weight. CAPs suitable for the described polymer foams preferably have a hydroxyl content of 0.5-5.0% by weight, or 0.5-3.0% by weight, or 1.0-2.5% by weight. Typically, it is 1.5 to 2.0% by weight, for example, 1.7% by weight. In addition, the glass transition temperature is preferably 140° C. to 155° C. Typically, it is 142° C. to 152° C., for example, 147° C.

[0042] According to one particular embodiment, the CAP has an acetyl content of 0.8-2.0% or 1.0-1.5% by weight and / or a propionyl content of 30-51% or 40-50% or 45-50% by weight and / or a hydroxyl content of 1.0-2.5% or 1.5-2.0% by weight.

[0043] According to one particular embodiment, the glass transition temperature of the CAP is from 100°C to 170°C, or from 120°C to 160°C, or from 140°C to 150°C.

[0044] According to one particular embodiment, the melting point of CAP is between 130°C and 230°C, or between 140°C and 220°C, or between 180°C and 220°C, or between 185°C and 210°C.

[0045] According to one particular embodiment, the second polymer is PBS.

[0046] According to one embodiment, when PBS is used, the number average molar mass of PBS suitable for the polymer foam is in the range of 30,000 to 100,000 Da. Typically, it is 50,000 to 80,000 Da, or 60,000 to 70,000 Da. The number average molar mass of PBS may be, for example, 65,000 to 70,000 Da, such as 68,000 Da, 69,000 Da, or 70,000 Da.

[0047] According to a particular embodiment, the glass transition temperature of PBS is from -50°C to 0°C, or from -40°C to -10°C, or from -35°C to -25°C.

[0048] According to a particular embodiment, the melting point of PBS is from 90°C to 160°C, or from 100°C to 140°C, or from 110°C to 130°C, or from 115°C to 120°C.

[0049] According to one very particular embodiment, the polymer foam comprises cellulose acetate propionate in an amount of 60-95 wt.%, typically 65-95 wt.%, or 70-95 wt.%, or 70-90 wt.%, and PBS in an amount of 5-40 wt.%, typically 5-35 wt.%, or 5-30 wt.%, or 8-30 wt.%, based on the total weight of the polymer foam.

[0050] Foaming agents are used to achieve the porous structure of the foam, and are typically divided into physical and chemical foaming agents.

[0051] Physical blowing agents can be divided into inorganic blowing agents and organic blowing agents. Physical inorganic blowing agents can be, for example, nitrogen, carbon dioxide, water, argon or air. Physical organic blowing agents can be low melting organic hydrocarbons such as isobutane, n-butane or n-pentane, cyclopentane, isopentane, or branched 5- and 6-carbon alkanes such as isopentane, isohexane, or 2,3-dimethylbutane, or fluorocarbons or chlorofluorocarbons such as dichloroethane or freon.

[0052] Chemical blowing agents can typically be divided into inorganic blowing agents and organic blowing agents. Chemical blowing agents work through two different methods: thermal decomposition and chemical reaction. Inorganic chemical blowing agents include bicarbonates such as sodium bicarbonate, carbonates, nitrites, zinc powder, chemical compounds that produce acid reactions, and hydrogen peroxide. Organic chemical blowing agents include citric acid, azodicarbonamide, azodicarbonamide, isocyanate compounds, nitroso blowing agents, and acylhydrazines.

[0053] According to one particular embodiment, the polymer foam is produced by using blowing agents such as nitrogen dioxide and / or carbon dioxide, which have been shown to work well with the polymers of the present disclosure in the solutions described.

[0054] Further suitable blowing agents can be found among known blowing agents. According to one embodiment, the at least one blowing agent is selected from the group consisting of nitrogen, carbon dioxide, water, argon, air, branched 5- and 6-carbon alkanes such as isobutane, n-butane, n-pentane, isopentane, isohexane or 2,3-dimethylbutane, fluorocarbons or chlorofluorocarbons such as dichloroethane or freon, bicarbonates such as sodium bicarbonate, carbonates, nitrites, zinc powder, chemical compounds that produce an acid reaction, hydrogen peroxide, citric acid, azodicarbonamide, azodicarbonamide, isocyanate compounds, nitroso blowing agents and acylhydrazines, or any combination thereof.

[0055] According to one particular embodiment, the polymer foam is produced by using a blowing agent in an amount of 0.1-10 wt%, or 0.3-10 wt%, or 0.5-10 wt%, or 0.5-7 wt%, or 0.5-5 wt%, or 1-5 wt%, or 1-4 wt%, or 1.5-3 wt%, based on the combined total weight of the first polymer and the second polymer used. The blowing agent may also be used in an amount of 0.1-5 wt%, or 0.1-4 wt%, or 0.1-3.5 wt%, or 0.3-3.5 wt%, which have been shown to work well with the polymers for polymer foams of the present disclosure in the solutions described.

[0056] Nucleating agents can be used in the production of polymer foams. Nucleating agents improve the nucleation of cells in polymer foams, reduce the size of the cells, provide uniform cell morphology, lower density and help to obtain good tensile properties. Nucleating agents can be active or can act to affect the rheological properties of the process properties, mechanical properties. Nucleating agents can be active or inactive. Nucleating agents can be inorganic compounds such as talc, calcium carbonate, silica or silicate compounds, graphite or calcium hydroxide. Organic nucleating agents can be natural waxes, polyethylene waxes, polyamide waxes and other synthetic waxes, or stearates such as calcium stearate, zinc stearate or aluminum stearate. Azodicarbonamide is also used as a nucleating agent. A combination of several nucleating agents can also be used. Nucleating agents can be added to the polymer as a powder, liquid or as a masterbatch.

[0057] According to one particular embodiment, the polymer foam includes a nucleating agent such as talc and / or calcium carbonate, which have been shown to work well with the polymers for the polymer foams of the present disclosure in the described solutions.

[0058] Further suitable nucleating agents can be found among known nucleating agents. According to one embodiment, the at least one nucleating agent is selected from the group consisting of talc, calcium carbonate, silica or silicate compounds, graphite, calcium hydroxide, natural waxes, polyethylene waxes, polyamide waxes or other synthetic waxes, stearates such as calcium stearate, zinc stearate, aluminum stearate, and azodicarbonamide, or any combination thereof.

[0059] The nucleating agents used as solid particles can have a variety of particle sizes. According to one embodiment, the median particle size of the nucleating agent is 0.5-10 μm, or 0.5-7 μm, or 1-5 μm, or 1-4 μm, or 1.5-3.5 μm, or 1.5-3 μm. These have been shown to work well with the polymers for the polymer foams of the present disclosure in the solutions described.

[0060] Nucleating agents can be used in various amounts. According to one embodiment, the polymer foam comprises nucleating agents in an amount of 0.05-10 wt%, or 0.05-7 wt%, or 0.1-5 wt%, or 0.1-3 wt%, or 0.1-1 wt%, or 0.15-0.6 wt%, based on the combined total weight of the first polymer and the second polymer used. These have been shown to work well with the polymers for the polymer foams of the present disclosure in the solutions described.

[0061] It has been found that the combination of using at least one nucleating agent and at least one blowing agent in certain amounts improves the quality of the polymer foam by reducing the density of the polymer foam and by improving the quality of the foam structure of the polymer foam.

[0062] According to one particular embodiment, the polymer foam comprises a nucleating agent in an amount of 0.05-10 wt%, or 0.05-7 wt%, or 0.1-5 wt%, or 0.1-3 wt%, or 0.1-1 wt%, or 0.15-0.6 wt%, based on the total combined weight of the first polymer and the second polymer used. Furthermore, the foam is produced by using a blowing agent in an amount of 0.5-10 wt%, or 0.5-7 wt%, or 0.5-5 wt%, or 1-5 wt%, or 1-4 wt%, or 1.5-3 wt%, based on the total combined weight of the first polymer and the second polymer used.

[0063] It has also been found that using a particular nucleating agent and blowing agent combination has a very favorable effect on the quality of the polymer foam.

[0064] The quality of a polymer foam is determined by the density of the foam, the cell structure of the foam, and the size of the cells of the foam. A polymer foam with a low density is preferred because the low density makes the foam lighter for the application. For example, in automobiles or packaging, it is desirable to make the final product as light as possible to save fuel or transportation costs. In addition to being light, the polymer foam must also have good mechanical performance, stability, and must not be brittle. These properties can be achieved by obtaining a polymer foam with a stable cell structure, small cell size, and uniform cells. A foam with very large cells is likely to be hard, but brittle, and therefore lacks mechanical properties. A foam with a non-uniform cell structure may have similar problems. Therefore, it is desirable for the polymer foam to be light, but with small, uniformly sized, and stable cells.

[0065] The inventors have found that a certain combination of nucleating agent and blowing agent results in a polymer foam with low density, good cell structure, and small cell size. Also, the polymer foam is stable despite the difference in melting point of the polymers. Surprisingly, for example, a polymer blend with 30% by weight of PBS polymer can form a stable polymer foam with a stable foam structure. This cure is obtained as a combination of blowing agent and nucleating agent.

[0066] As described below, some very specific embodiments are shown in the examples. For example, in the polymer blend containing 30 wt% PBS polymer, the examples show that this effect is very clear. When no nucleating agent is used, the cell structure of the polymer foam is poor. When using 1.5 wt% CO2 as the blowing agent and various amounts of talc and CaCO3 as the nucleating agent, the cell quality of the foam is moderate. However, surprisingly, when using 3.0 wt% CO2 as the blowing agent and 0.3 wt% talc as the nucleating agent, the cell quality of the polymer foam is good. This clearly shows the effect of combining the nucleating agent and the blowing agent.

[0067] It is also shown in the examples that similar effects are observed in polymer blends containing, for example, 20 wt% PBS polymer and in polymer blends containing only recycled polymer blends. When talc is used as a nucleating agent in an amount of 0.3 wt% and CO2 is used as a blowing agent in an amount of 1.5 wt%, the cell quality of the polymer foam is moderate. However, when 3.0 wt% CO2 is used as a blowing agent in combination with 0.3 wt% talc as a nucleating agent, the cell quality of the polymer foam is good. This also shows the effect of combining the nucleating agent and the blowing agent.

[0068] It is further shown in the examples that the combined effect is evident even in a polymer blend containing only 8 wt% PBS polymer. Foam samples made using this blend, using 0.3 wt% talc as a nucleating agent and either 1.5 wt% or 3.0 wt% CO2 as a blowing agent, are of good quality in terms of polymer foam cell structure. However, here, as the wt% of blowing agent increases from 1.5 wt% to 3.0 wt%, the density of the polymer foam increases to 54.2 g / cm3. 3 ~74.9g / cm 3 There is a combined effect on density as the

[0069] The examples show that there is a combined effect of the nucleating agent used and the blowing agent used on the quality of the foam structure of the polymer foam and the density of the polymer foam. The combined effect of the nucleating agent and the blowing agent is evident for many different ratios of polymers used in the polymer foam.

[0070] According to one particular embodiment, the polymer foam comprises talc and / or calcium carbonate as a nucleating agent, and the foam is produced by using nitrogen and / or carbon dioxide as a blowing agent.

[0071] Furthermore, chain extenders can be used in the production of polymer foams. Chain extenders are reactive additives or compounds that can form bonds with some polymer chain ends. By using chain extenders, more complex polymer chain structures are produced. The typical effect is an increase in tensile properties due to elongation and branching. The density of the foam is reduced and the tensile properties are improved. Typical chain extenders are, for example, low molecular weight aliphatic or aromatic diols or diamines, chain extenders can also be based on diesters or amino acids which can terminate in either a diol or diamine, some examples include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, 2-methyl-1,3-propylenediol, N,N'-bis(2-hydroxypropylaniline), water, 1,2-di(2-hydroxyethyl)hydroquinone, diethanolamine, triethanolamine, 1,1,1-trimethylolpropane, glycerol, dimethylolbutyric acid, hydrazine, ethylenediamine, isophoronediamine, 4,4' 4,4'-bis(sec-butylamine)dicyclohexylmethane, 4,4'-bis(sec-butylamine)diphenylmethane, diethyltoluenediamine, 4,4'-methylenebis(2-chloroaniline), 4-chloro-1,5-diamino-benzoic acid isobutyl ester, 3,5-dimethylthio-toluenediamine, trimethyleneglycol-di-p-aminobenzoate, 4,4'-methylenebis(3-chloro-1,6-diethylenediamine), 1,2-ethylenediol, 2-(methylalamino)ethanol, 1,4-butanediamine, ethylenediamine, diaminopropane, cyclohexanediphenylalanine, 1,3-propanediol, pentaerythritol or polyurethane polymers.

[0072] According to one embodiment, the polymer foam is produced using at least one chain extender.

[0073] Furthermore, crosslinking agents can be used in the production of polymer foams. Crosslinking agents are reactive additives or compounds that can chemically bond polymer chains together, resulting in bonds or chains of short bonds that connect one polymer chain to another. By using crosslinking agents, more complex polymer chain structures can be created and the resulting crosslinked polymers can have new properties such as mechanical properties, absorption properties, increased melt strength, or thermosetting properties. Crosslinking agents can be, for example, peroxides, silanes, azo compounds, or sulfur compounds, imides, hydrazides, azides, amines, epoxides, isocyanates, glutaraldehyde, dicarboxylic acids, citric acid, anhydrides, boric acid, or crosslinking can also be achieved by UV radiation crosslinking, ultrasonic crosslinking, or gamma radiation crosslinking.

[0074] According to one embodiment, the polymer foam is produced using at least one crosslinking agent.

[0075] Furthermore, fillers can be used in the manufacture of polymer foams. Fillers can be used to improve the mechanical properties of polymer foams. Fillers can also be used to provide new functional properties, such as flame retardant or antioxidant properties. The use of fillers can also improve the renewable content of polymer foams. Suitable fillers can be, for example, silicon dioxide, carbon black, clay, calcium sulfate, boron nitride, alumina trihydrate, magnesium hydroxide, cellulose fibers, glass fibers, carbon fibers, reinforcing fillers, wood flour, wood fines, wood particles, heat-treated wood particles, wood shavings, nano additives, nanocellulose, cellulose nanowhiskers, microcrystalline cellulose, lignin fibers, textile fibers, metal particles, thermoplastic polymer fibers, or any combination thereof. Fillers also include borates (zinc borate), diatomaceous earth, calcium carbonate, titanium dioxide, zinc oxide, zirconium oxide, iron oxide, ultramarine blue, cobalt salts (e.g., stannates, phosphates, aluminates), chromium oxide, cadmium salts and oxides, and lead salts and oxides, carbon nanotubes (CNTs), graphene, kaolin, talc, mica, calcium metasilicate, muscovite, phlogopite, Portland cement, wollastonite, magnesium silicate, barium sulfate, antimony trioxide, cotton, hemp fibers, The additives may be fiber, kenaf, sisal, bamboo, viscose, ceramic particles, microfibrillated cellulose, plasticizers, phthalates, adipates, benzoates (e.g., dipropylene glycol dibenzoate and blends thereof), citrates (e.g., sodium citrate), glyceryl monostearate, antioxidants, erythorbic acid, ascorbic acid, sodium erythorbate, sodium benzoate, potassium sorbate, attapulgite, montmorillonite, and alginates.

[0076] According to one embodiment, the polymer foam comprises at least one filler.

[0077] The polymer foams according to the present disclosure may further include other additives, such as optical brighteners, anti-slip agents, antioxidants, pigments, colorants, dyes, release agents, shock absorbers, heat stabilizers, whitening agents, antistatic agents, processing aids, UV stabilizers, lubricants, minerals, flow aids, flame retardants, additional polymers, and combinations thereof.

[0078] The additives can be used as solids, liquids, or masterbatches. When a masterbatch is used, the base polymer can be any of the polymers used in the polymer blend to produce the polymer foam, or other polymers such as aliphatic or aliphatic-aromatic polyesters or copolyesters. The base polymer can also be a polylactide. The base polymer can also be a conventional plastic polymer such as polyolefin, nylon, polystyrene, or any other thermoplastic polymer.

[0079] According to one embodiment, the polymer foam comprises at least one additive.

[0080] The polymer foam according to the present disclosure may further comprise other polymers. The polymer foam may further comprise a third polymer, such as polyethylene, polypropylene, polyamide, polyimide, styrene maleic anhydride, or block copolymers, such as styrene-butadiene block copolymer, styrene-isoprene block copolymer, or other polymers in which styrene monomers are used, such as SIBS or SEBS. The third polymer may also be a polyimide.

[0081] The terms "recycle" or "recycled" are to be understood herein, unless otherwise stated, as meaning the process of reprocessing and reusing a material, or the result of the process, such that the molecules in the material are available for reuse, either as polymers, monomers or smaller chemical building blocks. Recyclability refers to the ability to recycle a material for reuse. Preferably, the polymer foam should be recyclable, either mechanically or chemically, to allow the reuse of molecular materials. This is clearly stated in the European Commission's report (Plastics Strategy 2018) and in the basic principles of the circular economy.

[0082] Polymer foams often cannot be easily recycled for reuse purposes, and in fact, recycling is not well developed for many commonly used foam materials, such as polyurethane.

[0083] "Mechanical recycling" is a process in which, for example, polymer foam is taken, fed to a shredder to melt it, compounded into strands, and then pelletized. These recycled pellets can then be made into new polymer foam products.

[0084] "Chemical recycling" is the process of taking, for example, polymer foam and processing the material into smaller chemical components, such as synthesis gas, hydrogen mixture, H2, and carbon monoxide, CO. These chemical building blocks can then be used directly to make new monomers for new polymer products.

[0085] Different parts of polymers can be recycled in different ways. Cellulosic derivatives can undergo chemical recycling. Furthermore, many types of organic polymers can be used as feedstock for chemical recycling. Typically, the result of a chemical recycling process is a combination of, for example, synthesis gas, hydrogen H2, and carbon monoxide CO gas.

[0086] However, regeneration of the cellulose polymer structure itself as a result of chemical recycling is not currently practiced. However, the chemicals used to modify cellulose can be produced from chemically recycled raw materials. For example, the propionate and acetate groups in cellulose acetate propionate can be produced from chemically recycled raw materials.

[0087] Furthermore, some polymers such as polyesters and polylactides can be used as feedstocks for chemical recycling. The results of these recycling processes can vary depending on the process being used. Polyesters and polylactides can be hydrolyzed or depolymerized to oligomers, dimers or monomers. The polymers can also be reconstructed by using esterification, condensation or ring-opening processes. Polyesters and polylactides can also be used in thermochemical recycling processes, for example to produce synthesis gas (or other products). Catalytic pyrolysis can also be used. This mixture can then be further used to build monomers, or other chemical building blocks. Thus, polymers such as polyesters and polylactides can be used as feedstocks for chemical recycling processes. In addition, polymers such as polyesters and polylactides can be manufactured from materials that are the result of chemical recycling processes.

[0088] According to one embodiment, the polymer foam includes chemically recycled content.

[0089] According to one embodiment, the polymer foam contains a chemically recycled content of 5-80 wt%, or 20-70 wt%, or 30-60 wt%, or 40-50 wt%, based on the total weight of the polymer foam. The amount may be, for example, a chemically recycled content of 10-80 wt%, or 30-50 wt%, based on the total weight of the polymer foam. The chemically recycled content may also be, for example, 40-80 wt%, or 50-70 wt%, or 60-75 wt%. Preferably, the chemically recycled content is 5-40 wt%.

[0090] Currently, cellulose polymer derivatives cannot be made completely with chemically recycled content. Typically, the ester moiety in cellulose acetate propionate can be made from chemically recycled content. In practice, the maximum chemically recycled content in cellulose derivatives is therefore defined by the weight percent of ester moieties relative to the total weight of the cellulose polymer derivative. This can typically vary from 10% to 55% by weight depending on the ester moiety and the degree of substitution. This is the range of the maximum chemically recycled content in cellulose polymer derivatives as a weight percent of the total weight of the cellulose polymer derivative.

[0091] Other polymers, such as aliphatic polyesters, aliphatic-aromatic polyesters and copolyesters, and polylactides, can be made entirely from chemically recycled raw materials, thus the maximum chemically recycled content of polyester, for example, is 100% by weight.

[0092] When polymeric foams according to the present disclosure are produced, the chemically recycled content can vary from 50% to 80% by weight, typically where all ester groups in the cellulosic polymer, such as a cellulose polymer derivative, and the second polymer, such as a polyester or polylactide, are chemically made from recycled materials.

[0093] According to one particular embodiment, the chemically recycled content in the polymer foam is introduced into the cellulose acetate propionate, the propionate obtained via chemical recycling being more environmentally friendly than alternatively known methods.

[0094] Additionally, the polymer foam may be manufactured using mechanically recycled polymer blends. According to one embodiment, the polymer foam comprises a mechanically recycled polymer blend.

[0095] According to one embodiment, the polymer foam contains 5-100 wt% mechanically recycled content based on the total weight of the polymer foam. The amount of mechanically recycled content can also be, for example, 10-95 wt%, or 15-90 wt%, or 20-85 wt%, or 25-80 wt%, or 30-75 wt%. Mechanically recycled polymer blends exhibit good foam forming properties, which make them suitable for various foaming applications. The mechanically recycled content can also be 5 wt%, or 10 wt%, or 20 wt%, or 30 wt%, or 40 wt%, or 50 wt%, or 60 wt%, or 70 wt%, or 80 wt%, or 90 wt%, or 100 wt% of the total polymer blend used to produce the polymer foam.

[0096] According to one embodiment, the polymer foam includes both mechanically recycled content and chemically recycled content.

[0097] According to one particular embodiment, the polymer foam comprises a recycled polymer composition comprising cellulose acetate propionate (CAP) and polybutylene succinate (PBS) in an amount of 5-100% by weight, or 5-90% by weight, or 20-80% by weight, or 20-70% by weight, or 20-50% by weight, based on the combined total weight of the first polymer and the second polymer used.

[0098] According to one embodiment, the polymer foam may have a low environmental impact and a low carbon footprint.

[0099] The present disclosure also relates to a method for producing a polymer foam, the method comprising: providing a second polymer selected from cellulose acetate propionate (CAP), an aliphatic or aliphatic-aromatic polyester, or an aliphatic or aliphatic-aromatic copolyester, or a polylactide; mixing said cellulose acetate propionate (CAP) and said second polymer with at least one blowing agent and at least one nucleating agent to obtain a polymer mixture; forming the polymer mixture into a polymer foam by using a foam-producing method to obtain a polymer foam.

[0100] According to one embodiment, the polymer foam is made by extrusion foaming, bead foam extrusion, bead foaming process, autoclave foaming or foam injection molding method.

[0101] Extrusion foaming is a continuous process. In extrusion foaming, the foam structure is obtained by the expansion of a gas phase. The gas phase can be obtained by a chemical reaction using a chemical blowing agent. The gas phase can also be obtained by injecting a physical blowing agent into the polymer melt to obtain a homogeneous mixture of the blowing agent and the polymer melt, which leads to a decrease in the viscosity of the melt. The pressure increases due to the decrease in temperature, and the foam structure is formed by the separation of the dissolved gas from the gas phase.

[0102] The bead expansion extrusion or bead expansion process is a multi-step process in which the beads are expanded after extrusion of gas-filled non-expanded beads.

[0103] In autoclave foaming, an autoclave is charged with polymer and blowing agent under pressure.

[0104] In foam injection molding, the foam forming and injection molding processes are combined for lightweight injection molded articles.

[0105] According to one particular embodiment, the polymer foam is made by an extrusion foaming process, which has been shown to work well with the polymers of the present disclosure in the solutions described.

[0106] The foaming temperature is an important factor in extrusion foaming. In extrusion foaming, polymer foams are typically produced such that the foaming temperature is below or close to the transition temperature of the polymer used. This is due to the fact that the blowing agent acts as a plasticizer. The temperature reduction is also essential to reduce the polymer viscosity and effectively stabilize the foam structure. In addition, since the blowing agent, such as CO2, must diffuse out of the polymer foam structure and be exchanged with air even when the polymer foam is still cooling, the unstable polymer foam easily collapses under the pressure created by the diffusion.

[0107] According to one embodiment, the foaming temperature is close to or below the melting point of the cellulose acetate propionate when the second polymer is selected from the group of polymers with relatively low melting points and relatively low glass transition temperatures.

[0108] According to one embodiment, the polymer foam is produced using a foaming temperature of 220° C. or less, or 210° C. or less, or 205° C. or less, or 200° C. or less, or 195° C. The foaming temperature can also be from 120° C. to 210° C., or from 130° C. to 205° C., or from 140° C. to 200° C., or from 150° C. to 195° C.

[0109] According to one embodiment, the foaming temperature is close to or exceeds the melting point of the cellulose acetate propionate when the second polymer is selected from the group of polymers with relatively high melting points and relatively high glass transition temperatures.

[0110] According to one embodiment, the polymer foam is produced using a foaming temperature of 300°C or less, or 250°C or less, or 230°C or less.

[0111] According to one embodiment, the polymer foam is produced at a die pressure of 20-300 bar, 20-200 bar, or 30-150 bar, or 40-130 bar, or 40-120 bar, or 45-105 bar.

[0112] According to one embodiment, the polymer CAP and the second polymer are first melt mixed to form a granular product.

[0113] According to one embodiment, obtaining the polymer blend is performed by melt mixing. The melt mixing is performed at a temperature between 200° C. and 300° C. Preferably, the temperature is between 200° C. and 270° C., or between 210° C. and 250° C., or between 210° C. and 230° C.

[0114] Alternatively, the two polymers may be added directly to the foaming process without melt mixing.

[0115] According to one embodiment, obtaining the polymer blend is done by a recycling process.

[0116] The nucleating agent used in the foaming process may be mixed with the polymer granules prior to the foaming process. The nucleating agent may also be added directly in the foaming process using a feeder. According to one embodiment, the nucleating agent is mixed with the polymer blend prior to the foaming process.

[0117] The blowing agent used in the foaming process may be added in one stage, two stages, or multiple stages depending on the foaming process. The blowing agent may be fed into the process using a feeder or a pump. The blowing agent may also be added before the foaming process. The blowing agent may be added in gaseous or liquid form. Chemical blowing agents may also be added in solid form.

[0118] According to one embodiment, the method further comprises processing the resulting polymer foam into an article using a method selected from the group consisting of injection molding, 3D printing, deep drawing, cutting, sheet processing, and any combination thereof.

[0119] According to one embodiment, the polymer foam may be a thermoplastic polymer foam. The polymer foam may also be a thermosetting polymer foam. The polymer foam may also be a closed-cell polymer foam. The polymer foam may also be an open-cell polymer foam.

[0120] According to one embodiment, the density of the polymer foam according to the present disclosure is 10 g / cm 3 ~600g / cm 3 , or 15g / cm 3 ~500g / cm 3 , or 20 g / cm 3 ~400g / cm 3 , or 20 g / cm 3 ~250g / cm 3 , or 30 g / cm 3 ~200g / cm 3 , or 40 g / cm 3 ~190g / cm 3 , or 50g / cm 3 ~180g / cm 3 The density is also 50 g / cm 3 , or 60g / cm 3 , or 70g / cm 3 , or 80g / cm 3 , or 130g / cm 3 , or 140 g / cm 3 The density of the polymer foam according to the present disclosure may also be 150 g / cm 3 ~600g / cm 3 , or 150g / cm 3 ~500g / cm 3 , or 150~400g / cm 3 It could be.

[0121] According to one embodiment, the polymer foam is obtained with an average cell size of 0.01 mm to 5 mm, or 0.05 mm to 5 mm, or 0.1 mm to 5 mm, or 0.1 mm to 3 mm, or 0.1 mm to 2 mm, or 0.1 mm to 1 mm, typically 0.2 mm to 0.7 mm, or 0.2 mm to 0.6 mm, or 0.25 mm to 0.5 mm.

[0122] As the foam is formed in this process, the polymer foam expands. The expansion ratio is the diameter of the polymer foam divided by the diameter of the die used. According to one embodiment, a polymer foam having an expansion ratio of 1-10, or 2-8, or 3-6, or 3-5 is obtained. The expansion ratio can also be 3, or 3.8, or 4, or 4.5.

[0123] The present disclosure also relates to the use of the polymer foam according to any one of the described embodiments in the manufacture of an article selected from the group consisting of packaging, acoustic, thermal insulation, automotive, sporting goods, lightweight parts, construction, furniture, composite textiles, clothing, shoes and hats, car cushions, sporting goods, refrigerators, freezers, refrigerated containers, daily necessities, military industry, transportation, aerospace, seat cushions, thermal insulation materials, impact resistant materials, packaging materials, building materials, automotive, electrical and electronic applications, steel industry, aerospace, thermal insulation, high thermal stability, aerospace, aircraft, marine fields, memory foam, optical products and fibers, tobacco and e-cigarette filters, medical devices, dental molds and cushions, ear plugs, wearable audio, pads, tools, electric engines, acoustic damping, motion and impact dampers, flooring or filtration fields.

[0124] The polymer foams described herein can be a solution to increase renewable materials in foam applications and make foam more sustainable and recyclable. The polymer foams described herein can be produced using renewable cellulosic polymers or alternatively using recycled materials. They can provide the required performance and processability. One advantage of the polymer foams according to the present disclosure is that they can be produced using existing equipment without significant modification. The polymer foams described herein are lightweight and low density.

[0125] Some very specific embodiments are further described below.

[0126] According to one particular embodiment, the polymer foam comprises a recycled polymer composition comprising cellulose acetate propionate (CAP) and polybutylene succinate (PBS).

[0127] According to one particular embodiment, the polymer foam comprises a recycled polymer composition comprising cellulose acetate propionate (CAP) and polybutylene succinate (PBS) in an amount of 5-100% by weight, or 5-90% by weight, or 20-80% by weight, or 20-70% by weight, or 20-50% by weight, based on the combined total weight of the first polymer and the second polymer used.

[0128] According to one particular embodiment, the polymer foam comprises an additive.

[0129] According to one particular embodiment, the polymer foam comprises a filler.

[0130] According to one particular embodiment, the polymer foam is produced using a cross-linking agent.

[0131] According to one particular embodiment, the polymer foam comprises a third polymer.

[0132] According to one particular embodiment, the polymer foam is recyclable.

[0133] example Reference will now be made in detail to various embodiments, examples of which are illustrated in the accompanying drawings.

[0134] The following description discloses several embodiments in detail to enable one skilled in the art to utilize the embodiments based on the present disclosure. Not every step or feature of the embodiments is described in detail, and many of the steps or features will be apparent to one skilled in the art based on this specification.

[0135] For brevity, item numbers are maintained in the following exemplary embodiment where elements are repeated.

[0136] 1 and 2 show scanning electron microscopy of Example 4, polymer foam sample 1. Figure 1: Polymer foam sample 1, SEM image x10 Figure 2: Polymer foam sample 1, SEM image x25

[0137] 3 and 4 show scanning electron microscopy of Example 5, polymer foam sample 2. Figure 3: Polymer foam sample 2, SEM image x10 Figure 4: Polymer foam sample 2, SEM image x25

[0138] 5 and 6 show scanning electron microscopy of Reference Example 5, polymer foam sample 3. Figure 5: Polymer foam sample 3, SEM image x10 Figure 6: Polymer foam sample 3, SEM image x25

[0139] 7 and 8 show scanning electron microscopy of Example 5, polymer foam sample 4. Figure 7: Polymer foam sample 4, SEM image x10 Figure 8: Polymer foam sample 4, SEM image x25

[0140] 9 and 10 show scanning electron microscopy of Reference Example 5, Polymer Foam Sample 5. Figure 9: Polymer foam sample 5, SEM image x10 Figure 10: Polymer foam sample 5, SEM image x25

[0141] 11 and 12 show scanning electron microscopy of Example 5, polymer foam sample 6. Figure 11: Polymer foam sample 6, SEM image x10 Figure 12: Polymer foam sample 6, SEM image x25

[0142] 13 and 14 show scanning electron microscopy of Example 5, polymer foam sample 7. Figure 13: Polymer foam sample 7, SEM image x10 Figure 14: Polymer foam sample 7, SEM image x25

[0143] 15 and 16 show scanning electron microscopy of Example 5, polymer foam sample 8. Figure 15: Polymer foam sample 8, SEM image x10 Figure 16: Polymer foam sample 8, SEM image x25

[0144] 17 and 18 show scanning electron microscopy of Example 5, polymer foam sample 9. Figure 17: Polymer foam sample 9, SEM image x10 Figure 18: Polymer foam sample 9, SEM image x25

[0145] 19 and 20 show scanning electron microscopy of Example 5, polymer foam sample 10. Figure 19: Polymer foam sample 10, SEM image x10 Figure 20: Polymer foam sample 10, SEM image x25

[0146] 21 and 22 show scanning electron microscopy of Example 5, polymer foam sample 11. Figure 21: Polymer foam sample 11, SEM image x10 Figure 22: Polymer foam sample 11, SEM image x25

[0147] 23 and 24 show scanning electron microscopy of Example 5, polymer foam sample 12. Figure 23: Polymer foam sample 12, SEM image x10 Figure 24: Polymer foam sample 12, SEM image x25

[0148] 25 and 26 show scanning electron microscopy of Example 5, polymer foam sample 13. Figure 25: Polymer foam sample 13, SEM image x10 Figure 26: Polymer foam sample 13, SEM image x25

[0149] 27 and 28 show scanning electron microscopy of Example 5, polymer foam sample 14. Figure 27: Polymer foam sample 14, SEM image x10 Figure 28: Polymer foam sample 14, SEM image x25

[0150] The following polymeric materials were used in the examples and their properties are set forth in Tables 1-3. [Table 1] [Table 2]

[0151] The average molar mass (Mn) was measured using size exclusion chromatography (SEC) using chloroform eluent for number average molar mass measurement, samples were dissolved overnight using chloroform (concentration 1 mg / mL) and samples were filtered (0.45 μm) before measurement.

[0152] SEC measurements were performed using three columns, including a Styragel HR 4 and a precolumn, with chloroform eluent (0.6 mL / min, T=30° C.). Elution curves were detected using a Waters 2414 refractive index detector. Molar mass distributions (MMD) were calculated against a 10×PS (580-3,040,000 g / mol) standard using Waters Empower 3 software. [Table 3]

[0153] Example 1: Preparation of polymer blends for foam extrusion The polymer blends used for foam extrusion were prepared as follows: the first and second polymers, with or without additives, were fed to a melt mixing or compounding process. Compounding was done using a twin screw compounder. Compounding was done by strand pelletizing or underwater pelletizing. The temperatures used for the compounding process are as follows in Table 4.

[0154] Typical additives used in the formulation can be, for example, optical brighteners, anti-slip agents, antioxidants, pigments, colorants, dyes, release agents, impact absorbers, heat stabilizers, whitening agents, antistatic agents, processing aids, UV stabilizers, lubricants, minerals, flow aids, flame retardants, additional polymers, and combinations thereof.

[0155] The additives can be used as solids, liquids, or masterbatches. When a masterbatch is used, the base polymer can be any of the polymers used in polymer blends 1-3, or can be a bio-based polymer such as an aliphatic or aliphatic-aromatic polyester or copolyester. The base polymer can also be a polylactide. The base polymer can also be a conventional plastic polymer such as a polyolefin, nylon, polystyrene, or any other thermoplastic polymer. [Table 4]

[0156] Example 2: Preparation of recycled polymer blend 4 for foam extrusion Preparation of Recycled Polymer Blends for Foam Extrusion Blend 4 is a recycled blend.

[0157] Blend 1 and Blend 2 containing mixed waste film with additives were fed to a shredder, then melted and further extruded into strands and pelletized at a compounding process temperature of 210-220°C. The resulting granules were transparent and translucent. This recycled granule was used in the foam extrusion test as recycled Blend 4.

[0158] The recycled blend can be mixed with virgin polymer blends. The percentage of mechanically recycled content can vary, for example, from 5% to 100% by weight of the polymer foam.

[0159] Example 3: Method for preparing polymer foam The polymer foams were prepared using a Brabender Plastograpch EC Plus 19 mm single screw extruder. The extruder also had a 0.66 cm 3 It was equipped with a 1 / rev melt pump and an oil-tempered static mixer-type melt cooler. A three-phase compression process and extruder screw dimensions suitable for foaming were used, with an increased internal diameter at the blowing agent injection point. The extruder barrel was heated with three heating bands (zones) and the blowing agent was injected between zones 2 and 3. The extruder was also equipped with a round capillary die. The die dimensions were 2 / 20 (diameter / length, mm).

[0160] The foaming agent was injected and pressurized using a Teledyne ISCO dual syringe pump system. Carbon dioxide was fed into the Teledyne pump as it can be liquefied. The carbon dioxide injection pressure was 120 bar and the pump was cooled to 2°C for liquefaction.

[0161] Nitrogen was injected as a gas as it cannot be easily liquefied. A mass flow controller was used to administer the nitrogen injection.

[0162] Blowing agent dosage was calculated as a mass percentage based on material throughput, which was determined by manually measuring and weighing a 1 minute output sample.

[0163] During the foaming process, the extruder barrel temperature and the melt pump temperature were kept constant. The temperature was 220° C. The melt cooler temperature and the die temperature were varied. The melt cooler temperature and the die temperature are collectively referred to as the foaming temperature.

[0164] Polymer blends 1-3 were dried under vacuum at 60° C. before use. Recycled blend 4 was not dried.

[0165] The nucleating agent of Example 5 was sprinkled onto the polymer blend granules, mixed and then fed into the foaming extruder.

[0166] The density of the polymer foam samples was determined by a liquid immersion technique. The density of the foam samples was determined by first weighing the samples in air and then immersing them in distilled water. Pervitro's 75% Fuer solution was used to help reduce the surface tension of the water.

number

[0167] Scanning Electron Microscopy (SEM) was used to image the cell structure and cell size of the polymer foam samples. Prior to imaging, the foams were frozen and fractured using liquid nitrogen, and the fractured surfaces were gold coated using a Bal-Tec SCD050 sputter coater. A JEOL JSM-6360LV was used for SEM imaging.

[0168] Reference Example 4: Foam extrusion without nucleating agent Polymer blend 1 was introduced into a foaming extrusion process using 1.5 wt% CO2 as the foaming agent. The foaming temperature was 180°C. [Table 5]

[0169] Although a polymer foam was obtained, the quality of the cell structure was not good because the cell size was large and not uniform, the density was too high, the foam was brittle, and the cells tended to collapse by collapsing or splitting (Figure 1).

[0170] Example 5: Polymer foam extrusion using nucleating agents Polymer blends 1-4 were introduced into a foam extrusion process. Talc and CaCO3 were used as nucleating agents and their amounts were varied. The talc used was Finntalc M05SL with a median particle size of 2.2 μm. The CaCO3 used was Omycarb 2-GU calcium carbonate with a median particle size of 2.0 μm.

[0171] The amount of the foaming agent used was varied, and the foaming temperature was 155 to 195°C. [Table 6]

[0172] The effect of the nucleating agent on foam quality and density was clear. Comparing foam sample 1 in Table 5 with samples 2 to 7 in Table 6, it was found that the use of a nucleating agent clearly improved the foam density. The density measurements showed that by using only 0.15 wt% nucleating agent (foam sample 2), the foam density increased to about 130 (g / cm3) using talc. 3 Talc was found to be a more effective nucleating agent than CaCO3, with a polymer foam density level of 0.01 wt. % being achieved. When larger amounts of talc were used, there was no significant difference in foam density (foam samples 3 and 4). To achieve a similar density level with CaCO3, an amount of 0.60 wt. % CaCO3 was required (foam sample 7).

[0173] When the amount of CO2 was varied from 1.5 wt% to 3.0 wt%, the effect was clearly seen for all polymer blends 1 to 4. With higher amounts of CO2, the density of the polymer foams was clearly decreased for all polymer blends. The lowest density was 54.2 g / cm3. 3 Therefore, the lowest density was achieved for polymer blend 3 (foam sample 9). [Table 7]

[0174] In Table 7, all of the nucleated polymer foam samples (foam samples 2-14) have a cell structure as can be seen in Figures 2-14. The basic structure of the nucleated polymer foam is maintained as the foam exits the die and settles. The replacement of CO2 by air in the foam structure creates a state where the foam is stable and is under slight pressure within the polymer foam as it cools. However, the quality and size of the cells differ between the samples, resulting in different properties of the polymer foam.

[0175] In Table 7, poor quality polymer foam cells indicate that the cell size is very large or that the cells split during foam formation and as the blowing agent diffuses out of the polymer foam structure and is replaced by air, or collapse during cooling. Medium quality polymer foam cells indicate that some of the cells partially collapse or wrinkle during cooling as the blowing agent diffuses out of the polymer foam structure and is replaced by air. Good quality polymer foam cells show stable and small cells that are not collapsed or wrinkled. This means that the foam is stable during cooling and as the blowing agent diffuses out of the polymer foam structure and is replaced by air. The melt strength of the material is sufficient to adequately withstand the elongation effect of cell formation without the cells breaking.

[0176] In Figure 7, the cell size of the foams is shown as the average cell size, which was measured from SEM images (Figures 1-14).

[0177] The figure shows 10x and 25x SEM images of polymer foams. Polymer foam sample 1 had very large cells, many of which were torn. Polymer foams 2-7, 10, and 13 have medium quality cell structure. The cell structure is clearly formed, but some of the cells are wrinkled or have large cell sizes. Polymer foams 8, 9, 11, 12, and 14 have good cell structure with many uniform small cells. There are very few or no cell wrinkles.

[0178] This shows that even for polymer blends containing 30 wt% PBS polymer, the cell structure can be stable and of good quality despite the low melting point of the PBS polymer (foam sample 12). The average cell size of polymer blend 1 (foam samples 1-7 and 12) is reduced from 2.81 mm (foam sample 1) to 0.27 mm (foam sample 12) with the right combination of nucleating agent and blowing agent. The density of the foam made with polymer blend 1 is also reduced to 181.9 g / cm. 3 (Foam sample 1) 86.4 g / cm 3 (Foam Sample 12).

[0179] Similarly, for polymer blend 2 (foam samples 10 and 11), the cell size and quality are improved. With the same amount of nucleating agent, and by increasing the amount of blowing agent from 1.5 wt% to 3.0 wt%, the average cell size decreased from 0.36 mm to 0.23 mm. At the same time, the density increased from 105.3 g / cm3 to 105.3 g / cm3, respectively. 3 From 62.6 g / cm 3 It decreases to.

[0180] For polymer blend 3 and recycled blend 4, these effects were also evident.

[0181] It is obvious to those skilled in the art that with the advancement of technology, the basic idea can be realized in various ways. Therefore, the embodiments are not limited to the above examples, instead, they may vary within the scope of the claims.

[0182] The above-mentioned embodiments can be used in any combination with each other. Some embodiments may be combined to form further embodiments. The products, systems, methods or uses disclosed herein may include at least one of the embodiments described herein above. It will be understood that the benefits and advantages described above may relate to one embodiment or to several embodiments. The embodiments are not limited to those that solve any or all of the problems described or those that have any or all of the benefits and advantages described. It will be further understood that a reference to "an" item refers to one or more of those items. The term "comprising" is used herein to mean including the feature(s) or operation(s) that follows it without excluding the presence of one or more additional features or operations.

Claims

1. 1. A polymer foam, comprising: Cellulose acetate propionate (CAP), a second polymer selected from an aliphatic or aliphatic-aromatic polyester, an aliphatic or aliphatic-aromatic copolyester, or a polylactide; and at least one nucleating agent; Including, The polymer foam is produced by using at least one blowing agent; 1. A polymer foam comprising:

2. The polymer foam comprises, based on a total weight of the polymer foam, cellulose acetate propionate in an amount of 5 to 95% by weight; said second polymer in an amount of 95 to 5% by weight; 2. The polymer foam of claim 1, comprising:

3. 3. The polymer foam of claim 1, wherein the polymer foam comprises a combination of cellulose acetate propionate and the second polymer in an amount of at least 80 wt%, or at least 85 wt%, or at least 90 wt%, or at least 95 wt%, based on the total weight of the polymer foam.

4. 4. The polymer foam according to claim 1, characterized in that the polymer foam comprises cellulose acetate propionate in an amount of 30 to 95 wt%, or 40 to 95 wt%, or 50 to 90 wt%, or 55 to 90 wt%, or 60 to 90 wt%, or 70 to 90 wt%, and the second polymer in an amount of 5 to 70 wt%, or 5 to 60 wt%, or 10 to 50 wt%, or 10 to 45 wt%, or 10 to 40 wt%, or 10 to 30 wt%, based on the total weight of the polymer foam.

5. 5. The polymer foam of claim 1, wherein the second polymer is selected from the group consisting of polypropylene succinate (PPS), polybutylene succinate (PBS), polybutylene succinate adipate (PBSA), polybutylene adipate terephthalate (PBAT), polybutylene adipate (PBA), polycaprolactone (PCL), polyhydroxyalkanoates (PHAs) and polybutylene sebacate (PBSE), or any combination thereof.

6. The second polymer is 6. The polymer foam according to any one of claims 1 to 5, characterized in that it is selected from the group consisting of polylactic acid (PLA), polyethylene furanoate (PEF), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT) and polyglycolic acid (PGA) or any combination thereof.

7. The polymer foam according to any one of claims 1 to 6, characterized in that the second polymer is polybutylene succinate (PBS).

8. 8. The polymer foam of any one of claims 1 to 7, characterized in that the at least one blowing agent is selected from the group consisting of nitrogen, carbon dioxide, water, argon, air, branched 5 and 6 carbon alkanes such as isobutane, n-butane, n-pentane, isopentane, isohexane or 2,3-dimethylbutane, fluorocarbons or chlorofluorocarbons such as dichloroethane or freon, bicarbonates such as sodium bicarbonate, carbonates, nitrites, zinc powder, chemical compounds resulting in an acid reaction, hydrogen peroxide, citric acid, azodicarbonamide, isocyanate compounds, nitroso blowing agents and acylhydrazines, or any combination thereof.

9. 9. The polymer foam according to any one of claims 1 to 8, characterized in that the blowing agent is nitrogen and / or carbon dioxide.

10. 10. The polymer foam of any one of claims 1 to 9, characterized in that the polymer foam is produced by using at least one blowing agent in an amount of 0.1 to 10 wt%, or 0.3 to 10 wt%, or 0.5 to 10 wt%, or 0.5 to 7 wt%, or 0.5 to 5 wt%, or 1 to 5 wt%, or 1 to 4 wt%, or 1.5 to 3 wt%, based on the total weight of the cellulose acetate propionate (CAP) and the second polymer combined.

11. 11. The polymer foam according to any one of claims 1 to 10, characterized in that the nucleating agent is selected from the group consisting of talc, calcium carbonate, silica or silicate compounds, graphite, calcium hydroxide, natural waxes, polyethylene waxes, polyamide waxes or other synthetic waxes, and stearates such as calcium stearate, zinc stearate, aluminum stearate, and azodicarbonamide, or any combination thereof.

12. 12. The polymer foam according to claim 1, wherein the nucleating agent is talc and / or calcium carbonate.

13. 13. The polymer foam according to any one of the preceding claims, characterized in that the nucleating agent has a median particle size of 0.5 to 10 μm, or 0.5 to 7 μm, or 1 to 5 μm, or 1 to 4 μm, or 1.5 to 3.5 μm, or 1.5 to 3 μm.

14. 14. The polymer foam of any one of claims 1 to 13, characterized in that the polymer foam comprises a nucleating agent in an amount of 0.05 to 10 wt%, or 0.05 to 7 wt%, or 0.1 to 5 wt%, or 0.1 to 3 wt%, or 0.1 to 1 wt%, or 0.15 to 0.6 wt%, based on the total weight of the cellulose acetate propionate (CAP) and the second polymer combined.

15. 15. The polymer foam of any one of claims 1 to 14, characterized in that the polymer foam comprises a nucleating agent in an amount of 0.05 to 10 wt%, or 0.05 to 7 wt%, or 0.1 to 5 wt%, or 0.1 to 3 wt%, or 0.1 to 1 wt%, or 0.15 to 0.6 wt%, based on the total combined weight of the cellulose acetate propionate (CAP) and the second polymer, and the foam is produced by using a blowing agent in an amount of 0.1 to 10 wt%, or 0.3 to 10 wt%, or 0.5 to 10 wt%, or 0.5 to 7 wt%, or 0.5 to 5 wt%, or 1 to 5 wt%, or 1 to 4 wt%, or 1.5 to 3 wt%, based on the total combined weight of the cellulose acetate propionate and the second polymer used.

16. 16. The polymer foam of claim 1, wherein the polymer foam comprises talc and / or calcium carbonate as the nucleating agent, and the foam is produced by using nitrogen and / or carbon dioxide as the blowing agent.

17. Ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, 2-methyl-1,3-propylenediol, N,N'-bis(2-hydroxypropylaniline), water, 1,2-di(2-hydroxyethyl)hydroquinone, diethanolamine, triethanolamine, 1,1,1-trimethylolpropane, glycerol, dimethylolbutyric acid, hydrazine, ethylenediamine, isophoronediamine, 4,4'-bis(sec-butylamine)dicyclohexylmethane, 4,4'-bis(sec-butylamine)diphenylmethane, diethyltoluenediamine, 4,4' 17. The polymer foam of any one of claims 1 to 16, characterized in that the polymer foam is produced by further using a chain extender selected from the group consisting of: 4,4'-methylenebis(2-chloroaniline), 4-chloro-1,5-diamino-benzoic acid isobutyl ester, 3,5-dimethylthio-toluenediamine, trimethyleneglycol-di-p-aminobenzoate, 4,4'-methylenebis(3-chloro-1,6-diethyleneyline), 1,2-ethylenediol, 2-(methylalamino)ethanol, 1,4-butanediamine, ethylenediamine, diaminopropane and cyclohexanediphenylalanine, or any combination thereof.

18. 18. The polymer foam according to any one of claims 1 to 17, characterized in that the polymer foam is produced using a foaming temperature of at most 220°C, or at most 210°C, or at most 205°C, or at most 200°C, or at most 195°C.

19. An article manufactured using the polymer foam of any one of claims 1 to 18.

20. 20. The article of claim 19, selected from the group consisting of packaging, acoustics, thermal insulation, automotive, sporting goods, lightweight parts, construction, furniture, composite textiles, clothing, shoes and hats, car cushions, sporting goods, refrigerators, freezers, refrigerated containers, daily necessities, military industry, transportation, aerospace, seat cushions, thermal insulation materials, impact resistant materials, packaging materials, building materials, automotive, electrical and electronic applications, steel industry, aerospace, thermal insulation, high thermal stability, aerospace, aircraft, marine, memory foam, optical products and fibers, tobacco and e-cigarette filters, medical devices, dental molds and cushions, ear plugs, wearable audio, pads, tools, electrical engines, acoustic damping, motion and impact dampers, flooring or filtration fields.

21. 1. A method for producing a polymer foam, the method comprising: providing cellulose acetate propionate (CAP) and a second polymer selected from an aliphatic or aliphatic-aromatic polyester, or an aliphatic or aliphatic-aromatic copolyester, or a polylactide; - mixing the cellulose acetate propionate (CAP) and the second polymer with at least one blowing agent and at least one nucleating agent to obtain a polymer mixture; forming the polymer mixture into a polymer foam by using a foam generating method to obtain a polymer foam; A method comprising:

22. 22. The method according to claim 21, characterized in that the foam production process is selected from foam extrusion process, bead foaming process, bead foam extrusion, autoclave foaming or foam injection molding, preferably foam extrusion process.

23. The method according to any one of claims 21 and 22, characterized in that the polymer foam is a polymer foam according to any one of claims 1 to 27.

24. 24. The method according to any one of claims 21 to 23, characterized in that the polymer foam is produced using a foaming temperature of at most 220°C, or at most 210°C, or at most 205°C, or at most 200°C, or at most 195°C.

25. 25. The method according to any one of claims 21 to 24, characterized in that the polymer foam is produced at a die pressure of 20 to 300 bar, or 20 to 200 bar, or 30 to 150 bar, or 40 to 130 bar, or 40 to 120 bar, or 45 to 105 bar.

26. 26. The method of any one of claims 21 to 25, characterized in that the cellulose acetate propionate and the second polymer are formed into granules before being fed to the foaming process.

27. 27. The method according to claims 21 to 26, characterized in that obtaining the blend of the cellulose acetate propionate and the second polymer is carried out by melt mixing, and the melt mixing is carried out at a temperature of from 200°C to 300°C, or from 200°C to 270°C, or from 210°C to 250°C, or from 210°C to 230°C.

28. The method according to any one of claims 21 to 27, characterized in that obtaining the polymer blend is carried out by a recycling process.

29. 29. The method according to any one of claims 21 to 28, characterized in that the method further comprises a step in which the obtained polymer foam is processed into an article using a method selected from the group consisting of injection molding, 3D printing, deep drawing, cutting, sheet processing, or thermoforming, and any combination thereof.

30. 20. Use of the polymer foam according to any one of claims 1 to 18 in the manufacture of an article selected from the group consisting of packaging, acoustic, thermal insulation, automotive, sporting goods, lightweight parts, construction, furniture, composite textiles, clothing, shoes and hats, car cushions, sporting goods, refrigerators, freezers, refrigerated containers, daily necessities, military industry, transportation, aerospace, seat cushions, thermal insulation materials, impact resistant materials, packaging materials, building materials, automotive, electrical and electronic applications, steel industry, aerospace, thermal insulation, high thermal stability, aerospace, aircraft, marine fields, memory foam, optical products and fibers, tobacco and e-cigarette filters, medical devices, dental moulds and cushions, ear plugs, wearable audio, pads, tools, electrical engines, acoustic damping, motion and impact dampers, flooring or filtration fields.

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