LIGHTWEIGHT BIORESIN WITH GAS ASSISTANCE

Abstract

LIGHTWEIGHT BIORESIN WITH GAS ASSISTANCE A process for manufacturing a bio-based cellular plastic includes obtaining pellets of a non-cellular plastic having a density of less than 1 g / cm³; obtaining an algal product having a density greater than 1 g / cm³; injection molding the plastic pellets and the algal product, including the introduction of a chemical blowing agent, a physical blowing agent, or both; and producing a bio-based cellular plastic having a density equal to or less than 0.98 g / cm³. Figure for abstract: none

Description

Title of the invention: LIGHTWEIGHT BIORESIN WITH GAS ASSISTANCE SUMMARY

[0001] This disclosure relates to processes for introducing gas assistance (or gas injection) into a bio-based plastic resin blend to produce plastic components that are made less dense and can be recycled, and to packaging made using the lighter bio-based plastic resin blend. This can potentially be accomplished by physical foaming (e.g., using nitrogen or carbon dioxide), chemical foaming, or additives such as microspheres.

[0002] Since bio-based sources are rather dense, this poses a recyclability problem. Some bio-based composite plastics (for example, those including polypropylene or polyethylene) can become interfering with other plastics (for example, polyethylene terephthalate) when the density of the former is equal to or greater than 1 g / cm³, because a water bath is used to separate the materials by flotation. The objective would be to lower the density of the bio-based composite plastic to less than 1 g / cm³ so that the bio-based composite plastic resin floats and is properly recycled into the correct stream.Targeting plastic resins such as PP and PE and modifying their density via physical or chemical foaming or through additives to ensure that the density remains below 1 g / cm3 will guarantee that the plastic enters the correct recycling stream and stays away from other streams.

[0003] The disclosure relates to the introduction of a foaming agent, or a combination of foaming agent and / or gas assist, into a bio-based plastic resin.

[0004] The disclosure relates to an applicator or packaging structures including structures made from mixtures of aerated bio-based resins in which the total density of the material compound is equal to or less than 0.98 g / cm3, for example, a mixture of virgin, recycled and / or aerated bioresins.

[0005] Using a bio-based resin containing algae as an example, the non-cellular density of the bio-based resin is greater than 1 g / cm³, for example, from about 1.1 to about 1.7 g / cm³, and in one embodiment, about 1.4 g / cm³. However, when a physical or chemical foaming agent or a gas assist is introduced into the bio-based resin, the total density of the plastic compound can be equal to or less than 0.98 g / cm³. This density reduction is a combination of the bio-based resin and any plastic resin. virgin and physical foaming agent. For example, it is possible with physical foaming to reduce the density of a composition including, for example, 20% bio-based resin and 80% plastic to a density of 0.98 g / cm3 or less.

[0006] The purpose of this summary is to present a selection of concepts in a simplified form, which are described in greater detail below in the detailed description. This summary is not intended to identify key features of the claimed subject matter, nor to be used as an aid in determining the scope of the claimed subject matter. Description of the drawings

[0007] The foregoing aspects and many related advantages of the present invention will be more readily appreciated as they are better understood with reference to the following detailed description, when taken in conjunction with the accompanying drawings, in which:

[0008] [Fig. 1] FIGURE is a schematic illustration showing an injection molding system with introduction of physical or chemical blowing agent. Detailed description

[0009] Industry has sought ways to reduce the use of plastics made from fossil fuels, such as oil and coal, in order to reduce pollution. Bio-based plastics are made from natural polymers, such as carbohydrates and proteins. However, using algae as a source of bio-based plastic offers advantages over sourcing carbohydrates and proteins from terrestrial crops.

[0010] There are a plurality of processes for incorporating algae or an algae product into plastics. An example of a process for manufacturing algae powder is described in US patent application publication 2018 / 0258231. In general terms, the process of this publication includes the cultivation and / or harvesting of algae biomass, the reduction of at least 10% of the intrinsic protein content of the algae, by weight relative to the protein content of the harvested biomass, drying, and reducing to give powder or granules.

[0011] More specifically, the process according to publication 2018 / 0258231 includes carrying out an enzymatic hydrolysis of the algae proteins and separating the resulting protein material, which is rich in peptides and amino acids, from an algae residue in which the protein content is significantly reduced.

[0012] This disclosure relates to the use of algae products, such as the algae powder described in US Publication 2018 / 0258231, with resins in an injection molding process to produce cellular bio-based plastics having a density equal to or less than 0.98 g / cm³. In general, a Reducing the amount of fossil-based polymers in a compound is better for environmental impact. However, a problem encountered when incorporating an algae product with a plastic resin, such as propylene, is the increase in the resulting plastic's density. The disclosure aims to reduce the density of bio-based plastics by introducing a chemical or physical blowing agent, or both, into the molding process.

[0013] Non-cellular is used here to mean without bubbles or voids. Cellular describes a plastic that has cells, gas bubbles, or voids introduced by a physical or chemical blowing agent. Non-cellular polypropylene (PP) generally has a density of 0.895 to 0.97 g / cm³, depending on whether it is amorphous or crystalline. Non-cellular polyethylene (PE) generally has a density of 0.88 to 0.96 g / cm³. The density of polyethylene increases with crystallinity. Non-cellular ethylene-vinyl acetate (EVA) has a density of 0.92 to 0.97 g / cm³. A density of less than 1 g / cm³ allows polypropylene, polyethylene, or ethylene-vinyl acetate to be separated by flotation in fresh water, which generally has a density of 1 g / cm³. Flotation separation has become a commonly used process for separating a stream of mixed types of plastics for recycling.However, when the density of a bio-based plastic composite, including polypropylene, is greater than approximately 0.98 g / cm3, separation by flotation in water ceases to be a viable means of sorting polypropylene, which disrupts recycling facilities that may refuse to accept bio-based plastic.

[0014] The FIGURE is an illustration of a representative injection molding system 100. A representative injection molding system 100 includes a transfer screw 106 within a housing, a heating element 108 surrounding the transfer screw for melting the plastic pellets. The screw 106 pushes the molten plastic material into a mold 110, which can then be separated to recover the product.

[0015] In one embodiment, the non-cellular plastic pellets 112, the algae product 114 and a chemical blowing agent 116 are added into a hopper 102 which opens into the transfer screw 106.

[0016] In one embodiment, the non-cellular plastic pellets 112, the algae product 114 are introduced into the hopper and a physical blowing agent 118 is introduced directly into the transfer screw 106.

[0017] A suitable chemical blowing agent 116 can decompose when heated, producing one or more gases that will appear as voids or cells in the molded plastic part. Commonly used blowing agents include azo compounds, hydrazides, nitroso compounds, carbamates, Carbazides, bicarbonates, polycarboxylic acids, and salts of polycarboxylic acids. See US publication 2022 / 0372238.

[0018] A suitable physical blowing agent 118 is a gas, such as nitrogen gas or carbon dioxide gas. The physical blowing agent 118 can be introduced directly into the transfer screw section to mix directly with the molten mixture. The physical blowing agent will appear as voids or cells in the molded plastic part.

[0019] Suitable algae products 114 are derived from microalgae or macroalgae, such as green algae (Chlorophyceae), brown algae (Phaeophyceae), or red algae (Rhodophyceae), or algae of the genus Ulva or the family Sargassaceae. Examples of green algae are of the genus Ulva, such as Ulva armoricana or Ulva lactuca. Examples of microalgae are of the genus Chlorophyceae or diatoms.

[0020] A non-cellular plastic may include a plastic having a density of less than 1 g / cm³. When the non-cellular plastic has a density of less than 1 g / cm³, separation by flotation in fresh water may be carried out. Non-cellular polypropylene (PP) generally has a density between 0.895 and 0.92 g / cm³. Non-cellular low- and high-density polyethylene (PE) has a density between 0.88 and 0.97 g / cm³. Non-cellular ethylene-vinyl acetate (EVA) has a density of 0.92 to 0.97 g / cm³. Non-cellular polypropylene, ethylene, and ethylene-vinyl acetate may include additives, such as fibers, minerals, and talc, in percentages such that the density is less than 1.00 g / cm³. Non-cellular polypropylene, ethylene and ethylene-vinyl acetate can make up to 100% by weight of the respective polymer.

[0021] Flotation separation aims to separate PP and PE from PET. Therefore, plastics with a density greater than 1 (i.e., PET) are appropriately separated by a dense medium. The objective is to prevent PP and PE from disrupting the PET flow.

[0022] An algae product comprises starch, proteins, and other compounds naturally present in algae. The algae are processed to provide a form suitable for mixing with plastics in injection molding, extrusion, and similar plastic forming processes. Generally, the algae product has been processed and has a density greater than 1 g / cm³.

[0023] In one embodiment, the weight ratio range between the algae product and the non-cellular plastic is 0.25 or less, but greater than 0.01. The amount of chemical or physical blowing agent is determined to give a density of 0.98 g / cm3 or less to the molded bio-based cellular plastic.

[0024] A process for manufacturing a bio-based cellular plastic includes obtaining pellets of a non-cellular plastic having a density of less than 1 g / cm³; obtaining an algae product having a density greater than 1 g / cm³; injection molding the plastic pellets and the algae product, including the introduction of a chemical blowing agent, a physical blowing agent, or both; and producing a bio-based cellular plastic having a density equal to or less than 0.98 g / cm³. The process may include a step of adding additives to the mixture, for example, colorants, plasticizers, UV stabilizers, and the like.

[0025] Non-cellular plastic is a plastic of fossil origin. The plastics used may be virgin, post-consumer recycled, post-industrial recycled and / or chemically recycled.

[0026] The non-cellular plastic is a polyolefin.

[0027] Non-cellular plastic has a density of 0.88 to 0.97 g / cm3.

[0028] The non-cellular plastic comprises polypropylene or polyethylene or ethylene-vinyl acetate, or any composite including one or more of these polymers.

[0029] The algae product is a powder from which at least 10% by weight of the proteins have been removed.

[0030] The weight ratio range of the algae product to the non-cellular plastic is from 0.25 to 0.01. The weight ratio range of the algae product to the non-cellular plastic is from 0.20 to 0.01. The weight ratio range of the algae product to the non-cellular plastic is from 0.15 to 0.01. The weight ratio range of the algae product to the non-cellular plastic is from 0.10 to 0.01.

[0031] The physical blowing agent is nitrogen or carbon dioxide.

[0032] The non-cellular plastic is polypropylene. Polypropylene may include additives, for example colorants, plasticizers, UV stabilizers, and the like.

[0033] Non-cellular plastic is polyethylene. Polyethylene may include additives, for example colorants, plasticizers, UV stabilizers, and the like.

[0034] A bio-based cellular plastic manufactured by the above process, comprises a mixture of polypropylene or polyethylene or both with the algae product; and the bio-based plastic has a density equal to or less than 0.98 g / cm3; and cells within the plastic.

[0035] The weight ratio range of the algae product to the polypropylene or polyethylene is from 0.25 to 0.01. The weight ratio range of the algae product to the The weight ratio of the algae product to the polypropylene or polyethylene ranges from 0.20 to 0.01. The weight ratio range of the algae product to the polypropylene or polyethylene ranges from 0.15 to 0.01. The weight ratio range of the algae product to the polypropylene or polyethylene ranges from 0.10 to 0.01.

[0036] The bio-based cellular plastic is configured to be separated in a flotation separation in fresh water.

[0037] Although illustrative embodiments have been shown and described, it will be appreciated that various changes can be made to them without departing from the spirit and scope of the invention.

Claims

Demands

1. A process for manufacturing a bio-based cellular plastic, comprising: obtaining pellets of a non-cellular plastic having a density of less than 1 g / cm3; obtaining an algae product having a density greater than 1 g / cm3; injection molding the plastic pellets and the algae product including the introduction of a chemical blowing agent, a physical blowing agent, or both; and producing a bio-based cellular plastic having a density equal to or less than 0.98 g / cm3.

2. A method according to claim 1, wherein the non-cellular plastic has a density of 0.88 to 0.97 g / cm3.

3. A method according to claim 1, wherein the non-cellular plastic comprises polypropylene or polyethylene or ethylene-vinyl acetate.

4. A process according to claim 1, wherein the seaweed product is a powder from which at least 10% by weight of the proteins are removed.

5. A method according to claim 1, wherein the weight ratio range of the algae product on the non-cellular plastic is from 0.25 to 0.

01.

6. A method according to claim 1, wherein the weight ratio range of the algae product on the non-cellular plastic is from 0.20 to 0.

01.

7. A method according to claim 1, wherein the weight ratio range of the algae product on the non-cellular plastic is from 0.15 to 0.

01.

8. A method according to claim 1, wherein the weight ratio range of the algae product on the non-cellular plastic is from 0.10 to 0.

01.

9. A method according to claim 1, wherein the physical blowing agent is nitrogen or carbon dioxide.

10. A method according to claim 1, wherein the non-cellular plastic includes polypropylene or polyethylene.

Images