TW202237729A - Degradable polymer and method of production - Google Patents

Abstract

The present invention provides a degradable polymer composition comprising: an additive; optionally 30 to 80wt% calcium carbonate by weight of the composition; and the balance a polymer comprising one or more polyolefins, wherein the additive comprises, by combined weight of the additive and the polymer: (a) two or more transition metal compounds in a total amount of from 0.15 to 0.5wt%, said compounds comprising 3wt% or less volatiles; (b) a mono- or poly-unsaturated C14-C24 carboxylic acid, or an ester, anhydride or amide thereof, in an amount of from 0.04 to 0.16wt%; (c) a synthetic rubber in an amount of from 0.04 to 0.2wt%, wherein the rubber is free from halides and bisphenol A; (d) a phenolic and/or phosphite antioxidant stabilizer in an amount of from 0.01 to 0.2 wt%; and, optionally: (e) dry starch in an amount of from 0 to 10wt%; and/or (f) calcium oxide in an amount of from 0 to 1 wt%; and/or wherein the two or more transition metal compounds are selected from iron, manganese, copper, zinc, titanium, cobalt and cerium compounds and wherein the transition metals in the two or more transition metal compounds are different.

Description

Degradable polymer and manufacturing method

The disclosure of this case relates to a polymer composition, in particular to a degradable composition with adjustable degradation rate and improved material properties, and the disclosure of this case also relates to the preparation of said composition method.

Polymeric materials have many advantages and can provide robust, chemically and biologically inert materials at relatively low cost. Unfortunately, many of these properties make polymeric materials difficult to dispose of without causing lasting damage to the environment. Their low cost and good mechanical properties mean that polymer materials are often used with very short functional lifetimes. This results in a rapid accumulation of waste material that is unresponsive to most of the physical and chemical actions waste materials are subjected to during conventional disposal, such as dumping in landfills.

As people become more aware of the anthropogenic impact on our climate, our ecosystems, and the planet as a whole, the need to reduce the amount of non-degradable waste disposed of in landfills continues to grow. Therefore, there is an increasing need for degradable alternatives to conventional polymeric materials. In particular, there is a huge demand for degradable polymer compositions that can be formed into sheets and films for use in various common applications, such as packaging.

Several degradable polymer compositions have been developed. However, there are significant disadvantages associated with these known degradable polymers. Conventional degradable polymers, such as aliphatic polyesters, are generally more difficult and complex to handle, resulting in lower output. These materials have significantly higher densities and lower strengths than conventional non-degradable commercial polymers.

US 4,016,117 discloses the use of biodegradable filler materials such as starch and autoxidizing substances such as fats which, when exposed to transition metals in soil, produce peroxides which attack the carbon-carbon bonds in the resin .

US 4,931,488 discloses that adding a biodegradable substance (starch), an iron compound (FeOH(stearate) ₂ ) and a fatty acid or fatty acid ester such as soybean oil, which is a mixture of fatty acid esters, to thermoplastic polymers middle. The resulting plastic composition will degrade under the action of heat and/or ultraviolet light and/or sunlight. These compositions have unfavorable abiotic and biodegradation rates.

WO 2018/095905 discloses degradable polymer compositions. WO 2018/134071 discloses degradable sheets.

Accordingly, it would be desirable to provide degradable polymer compositions and methods of manufacture that address at least some of the problems associated with the prior art, or at least provide a commercially practical alternative thereto.

A feature of the invention is a polyolefin-based plastic with additives that can be recycled in an existing polyolefin recycling stream before degradation begins.

According to the first aspect, there is provided a degradable polymer composition, comprising: an additive; optionally, calcium carbonate accounting for 30-80wt% of the weight of the composition; and the rest is a polymer, the polymer comprising one or A plurality of polyolefins, wherein, based on the total weight of the additive and the polymer, the additive comprises: (a) two or more transition metal compounds in a total amount of 0.15-0.5 wt%, the compound comprising 3 wt% or Less volatiles; (b) mono- or polyunsaturated _C14 - _C24 carboxylic acids, or their esters, anhydrides or amides, in amounts of 0.04 to 0.16 wt. %; (c) synthetic rubbers, in amounts of 0.04 to 0.2 wt%, wherein the rubber is free of halides and bisphenol A (bisphenol A); (d) phenolic and/or phosphite antioxidant stabilizers in an amount of 0.01 to 0.2 wt%; and, Optionally: (e) dry starch in an amount of 0 to 10 wt%; and/or (f) calcium oxide in an amount of 0 to 1 wt%; and/or wherein the two or more transition metals The compound is selected from iron, manganese, copper, zinc, titanium, cobalt, and cerium compounds, and wherein the transition metals in the two or more transition metal compounds are different.

Preferably, the additive consists essentially of the listed ingredients (a) to (f). Preferably, the composition consists essentially of additives, calcium carbonate and polymers. That is, preferably, the composition contains less than 5wt% of other components, more preferably less than 1wt% of other components, and most preferably does not contain other components.

The present invention will now be further described. In the following paragraphs, different aspects of the invention are defined in more detail. Each aspect so defined may be combined with any other aspect or aspects unless expressly indicated to the contrary. In particular, any feature indicated as preferred or advantageous may be combined with any other feature or features indicated as preferred or advantageous.

The composition is a degradable composition. The term "degradable" is used in the description below to refer to synthetic polymer components that decompose into CO ₂ , H ₂ O, biomass, and inorganic salts under normal composting conditions and in other environments.

As can be appreciated, calcium carbonate (when present) does not decompose but remains as an inert powder component once the polymer has degraded. Accordingly, the discussion below refers interchangeably to degradation of the composition and degradation of the polymers that form the structure of the sheet. Advantageously, the sheets described herein are even recyclable, as calcium carbonate/polyethylene masterbatches are often added to the recyclate to improve handling. That is, high calcium carbonate content does not hinder recovery. Due to the low polymer content, these sheets can even be compostable under certain conditions.

The composition optionally comprises from 30 to 80 wt% calcium carbonate by weight of the composition. Calcium carbonate is cheap, abundant in nature and renewable. Calcium carbonate is widely used in personal care applications, paper whitening, indigestion tablets, etc. Calcium carbonate, when oxidized, forms lime (calcium oxide), which is often added to drinking water. Calcium carbonate can come from chalk mine, shells, or eggshells. Preferably, the composition contains 50 to 75 wt%, most preferably 60 to 70 wt% calcium carbonate.

The addition of calcium carbonate provides a strong final material that breaks easily once degradation begins, is inexpensive and is less environmentally impactful. Preferably, the average longest diameter of the calcium carbonate is 1 to 30 microns, more preferably 1 to 20 microns. This is desirable for good distribution within the polymer and allows easy handling of the composition, including extrusion.

Calcium carbonate is retained within the polymer as described herein. These polymers preferably provide 19 to 69% by weight of the composition, the balance being additives and calcium carbonate. Preferably, the polymer is PP, LLDPE, LDPE or HDPE. Preferably, the polymer has a melt flow index of 1 to 40, as this allows for good handling of calcium carbonate-containing compositions as described herein.

It is known to include calcium carbonate in polymers. For example, natural mineral paper (NMP) is a composite material consisting almost up to 80% of calcium carbonate (rock mineral) and an organic binder HDPE (high-density polyethylene). Invented in the 1970s, this material has found use only in niche markets such as luxury bags, tags, luggage tags, and stationery.

Additionally, the addition of calcium carbonate to polyolefins is commonly used as this can improve processing time and reduce costs by increasing the weight/volume of the material. These materials can also have improved tensile and light blocking properties. Masterbatches have been developed that improve the handling of recycled products by improving the miscibility between different polymers, especially in the case of 3- or 5-layer films with gas barrier layers.

The "paper" that forms natural mineral paper retains many of the properties of paper, such as clean dead-fold and good ink retention, but it is also water-resistant, tear-resistant, and can be produced cheaper and cleaner, so It uses less energy, water, and requires no bleach. Many current manufacturers claim that it is photodegradable, perhaps due to the ferric oxide impurity in the chalk, but no timeline for degradation is given - and given this nature, it has not yet been considered. for wider use potential. This generation of stone paper (NMP) generally contains a calcium carbonate: HDPE ratio of 80:20 (this is for paper thicknesses less than 300 µm, which are used as printing paper, labels, etc., paper bags) and 60 :40 (this is for paper thicknesses over 300 µm, which are used as cards, glossy boxes, etc.).

In addition to the calcium carbonate and other components described herein, the compositions of the sheets discussed herein may contain other particles, such as metal carbonates and other particles of metal oxides. However, the presence of such additional particles is preferably less than 20% by weight of the composition, more preferably less than 5% by weight, most preferably less than 1% by weight. In preferred embodiments, the composition consists of the components described herein without any other particles.

The additive comprises two or more transition metal compounds in a total amount of 0.15 to 0.5 wt%, preferably 0.2 to 0.3 wt%, based on the total weight of additive and polymer. The following description uses the term transition metal to refer to any metallic element of Groups IVB-VIII, IB, and IIB or Groups 4-12 of the Periodic Table. Preferred transition metals are iron, manganese, copper, cobalt and cerium, preferably in the +3 oxidation state where iron is used and in the +2 oxidation state where copper is used. These compounds catalyze degradation. Incorporating large amounts of transition metals increases the cost of the degradable composition and may lead to accumulation of transition metals at waste disposal sites. Furthermore, increasing the transition metal content beyond these amounts has a reduced effect on the degradation rate since transition metals play a catalytic role in the degradation process.

Crucially, the transition metal compound must contain 3 wt% or less of volatile components (based on the weight of the supplied transition metal compound). Such volatile components include water and small organic compounds. The inventors have found that the presence of such ingredients interrupts the production of the composition and also reduces the control over the degradation of the composition.

Two or more transition metal compounds are selected from iron (preferably ferric), manganese, copper, zinc, titanium, cobalt, and cerium compounds, and the transition metals in the two or more transition metal compounds are different .

Preferably, the transition metals in the two or more transition metal compounds include: (i) iron, manganese and copper; or (ii) manganese and copper; or (iii) Iron and manganese.

The temperature of the polymer composition and its exposure to light may also affect its degradation rate. The inventors of the present case have unexpectedly discovered that the choice of transition metal can be used to further tune these effects. In particular, the inventors of the present case have found that iron is a more effective photocatalyst for the degradation process, while manganese is a more effective thermal catalyst for the degradation process. Thus, transition metal components can be used to tune degradation rates based on the expected exposure to heat and light for a particular product.

Certain transition metals may affect the properties of polymer compositions. For example, iron compounds can color polymer compositions.

Furthermore, other metals such as copper advantageously increase the rate of degradation, but make polymer compositions unsuitable for certain applications due to their toxicity. Iron can be avoided in color sensitive compositions. Copper can be avoided when used in the food industry.

Preferably, the transition metal compound comprises moieties selected from stearate, carboxylate, acetylacetonate, triazacyclononane or any of the above combination of two or more. Preferably, the transition metal compound may exist in the following manner: the weight ratio of iron stearate (iron stearate) and manganese stearate to copper stearate is 4:1 to 8:1. Preferably, the transition metal compound may exist in the following manner: the weight ratio of ferric stearate and manganese stearate to copper stearate is 4:1 to 8:1.

Alternatively or additionally, certain non-ionic ligands that play an active role in degradation may also be incorporated. When present, non-ionic ligands are preferably selected from the group consisting of amines, imines, amides, phosphites, phosphines and carbenes. The inventors of the present case have discovered that such non-ionic ligands can have a favorable effect on the degradation rate of the composition while maintaining the basic material properties. The non-ionic ligands preferably constitute at least 5% of the ligands, preferably up to 50% of the ligands, preferably 10 to 40% of the ligands.

Preferably, the transition metal ligand is chosen such that the transition metal is physically and chemically compatible with the polymer. Advantageously, the choice of ligand may affect the catalytic activity of transition metals. The ligands can be chosen to make the metal compatible with the particular polyolefin used and to control the rate of degradation of the polymer composition.

Preferably, the ligands of the metal compound are inorganic ligands and/or saturated organic ligands. Preferably, the ligand of the metal compound does not contain mono- or multi-unsaturated C14-C24 carboxylic acid or its ester, anhydride, or amide.

The additive comprises mono- or polyunsaturated C ₁₄ -C ₂₄ carboxylic acid in an amount of 0.04 to 0.16 wt%, preferably 0.04 to 0.06 wt%, based on the total weight of additive and polymer. The description below uses the term carboxylic acid to refer to a range of molecules containing a carboxylic acid -(COOH) site. The carboxylic acid of the present invention is monounsaturated or polyunsaturated and has a carbon skeleton with 14 to 24 carbon atoms, which means that it has at least one double bond in the carbon skeleton. The carbon backbone of carboxylic acids can be linear, branched or aromatic. Preferably, the mono- or polyunsaturated carboxylic acid is a C ₁₆ -C ₂₀ carboxylic acid. Preferred carboxylic acids are oleic acid, linoleic acid, and cinnamic acid, and most preferably, the carboxylic acid is oleic acid.

Alternatively, the additive comprises 0.04-0.16 wt%, preferably 0.04-0.06 wt%, based on the total weight of additive and polymer, of esters, anhydrides or amides of mono- or polyunsaturated _C14 - _C24 carboxylic acids.

The carboxylic acid or ester, anhydride, or amide components are preferably "free" or "uncomplexed", in the sense that they do not form part of the transition metal compound.

When the additive comprises esters of mono- or polyunsaturated C ₁₄ -C ₂₄ carboxylic acids, the alcohol component preferably comprises C ₁ -C ₃₀ alcohols, more preferably saturated linear C ₁ -C ₃₀ alcohols.

When the additive comprises an anhydride of a mono- or polyunsaturated _C14 - _C24 carboxylic acid, the anhydride may be symmetrical or asymmetrical. The second carboxylic acid component preferably comprises a C ₁ -C ₃₀ carboxylic acid, more preferably a saturated linear C ₁ -C ₃₀ carboxylic acid.

When the additive comprises an amide of a mono- or polyunsaturated C ₁₄ -C ₂₄ carboxylic acid, the amide may be a primary, secondary or tertiary amide. When secondary or tertiary amides are present, each carbon chain preferably contains 1 to 30 carbon atoms, more preferably each carbon chain is C ₁ -C ₃₀ alkyl.

Unless otherwise stated, when carboxylic acids are characterized in this specification it is intended to encompass their esters, anhydrides or amides.

Without wishing to be bound by theory, it is believed that the units or polyunsaturated C ₁₄ -C ₂₄ carboxylic acids in the polymer composition autoxidize to produce peroxides which are capable of attacking the carbon-carbon bonds of the polymer chain, Renders the polymer susceptible to normal degradation procedures. The presence of transition metals catalyzes autoxidation, thereby increasing the degradation rate of the constituents.

Inclusion of greater than 0.16 wt% of units or polyunsaturated C ₁₄ -C ₂₄ carboxylic acids may lead to excessive air sensitivity of the polymer. Excessive autoxidation of carboxylic acids may lead to relatively high peroxide concentrations and rapid decomposition of polymer structures. This can cause issues with shelf life. Conversely, inclusion of less than 0.04 wt% of mono or polyunsaturated C ₁₄ -C ₂₄ carboxylic acids may result in negligible degradation rates. The inventors have found that the inclusion of between 0.04 and 0.16 wt% of mono- or polyunsaturated C ₁₄ -C ₂₄ carboxylic acids allows tailoring the degradation rate to values required for many applications.

Surprisingly, the inventors of the present case have found that linear monounsaturated acids (especially oleic acid) show the greatest influence on the degradation rate. This cannot be expected from the individual chemical stability of these compounds, since in general, the more double bonds in a carboxylic acid, the more susceptible it is to oxidation.

The additive comprises synthetic rubber in an amount of 0.04 to 0.2 wt%, preferably 0.08 to 0.12 wt%, most preferably about 0.1 wt%, based on the total weight of additive and polymer. The following description uses the term rubber to refer to viscous, elastic polymers. Rubber is an amorphous polymer that exists at temperatures above its glass transition temperature. Preferably, the rubber of the present invention is unsaturated rubber, more preferably, the rubber of the present invention comprises polyisoprene, styrene-isoprene, styrene-isoprene-styrene or the above A mixture of two or more of them.

The rubber content can advantageously improve the mechanical properties of the polymer composition. Additionally, rubbers are generally less chemically stable than bulk polyolefins. Thus, the rubber content can improve the degradation rate without adversely affecting the physical properties of the polymer. In this way, it appears to act as a co-catalyst.

Crucially, the synthetic rubber must be free of any coupling agents, including halides or bisphenol A. These additives are undesirable in providing the degradable compositions of the present invention.

Advantageously, the presence of synthetic rubber in the polymer composition improves elasticity. This helps to counteract embrittlement of the polymer composition caused by other additives. Inclusion of less than 0.04% synthetic rubber may render the polymer too brittle and unsuitable. Inclusion of more than 0.2% synthetic rubber may lead to rapid degradation and may adversely affect the material properties of the polymer. Additionally, it is believed that the synthetic rubber content increases the degradation rate without increasing the transition metal, starch or carboxylic acid content.

The additive optionally comprises dry starch in an amount of 0 to 10 wt%, preferably 0.1 to 1 wt%, most preferably 0.1 to 0.4 wt%, based on the total weight of additive and polymer. The following description uses the term starch to refer to a polysaccharide comprising a large number (typically 500-2,000,000 monomer units) of glucose units linked by glycosidic bonds. The starch of the present invention is dry starch. That is, the starch contains less than 5% water by weight of the starch, preferably less than 1% water by weight, most preferably the starch contains substantially no water.

Inclusion of large amounts of starch increases the density and reduces the tensile strength of the polymer. Additionally, high starch content may cause shelf life issues due to rapid degradation. The high starch content makes the polymer content susceptible to cosmetic and physical damage from exposure to water and microorganisms. If the starch content is insufficient, the effect of the additive on the rate of biodegradation may be minimal.

The additive optionally comprises calcium oxide in an amount of 0-1 wt%, preferably 0-0.4 wt%, more preferably 0.1-0.3 wt%, based on the total weight of additive and polymer. The following description uses the term calcium oxide to refer to the crystalline solid having the chemical formula CaO. Advantageously, calcium oxide reacts with and immobilizes water in the composition. This stabilizes the composition during processing and reduces the occurrence of blemishes and discoloration in the final product. Unexpectedly and unexpectedly, the inventors of the present case have also found that increasing the calcium oxide content of the polymer composition can increase the degradation rate. Advantageously, the CaO content can be used to improve degradability without increasing the transition metal content of starch. Inclusion of more than 0.4 wt% CaO leads to embrittlement of the polymer.

The additives include phenolic and/or phosphite antioxidant stabilizers in an amount of 0.01 to 0.2 wt%, preferably 0.02 to 0.15 wt%. Phenolic and phosphite antioxidant stabilizers are known in the art and include, for example, Irganox 1076 and Irganox 1010 as phenolic antioxidant stabilizers, and Irgaphos 168 as a phosphite antioxidant stabilizer. It was found that phenolic and/or phosphite antioxidant stabilizers allow increased control over the degradation time of the polymer. In particular, the incorporation of phenolic and/or phosphite antioxidant stabilizers can delay the onset of degradation, thereby extending the shelf life of the product and the period during which the product can be recovered in existing polyolefin recovery streams.

Preferably, the additives further include color additives such as but not limited to carbon black or titanium oxide.

The composition comprises: a polymer comprising one or more polyolefins. Preferably, the one or more polyolefins comprise ethylene and/or propylene monomers, optionally further comprising acetate, vinylacetate, methyl methacrylate, vinyl alcohol and Selected monomers of acrylic acid. Preferably, the polyolefin is selected from PP, LDPE, LLDPE, HDPE, MDPE, VLDPE, EVA, EVOH, EMMA and EAA.

Preferably, the degradable polymer is in the form of a sheet material, preferably a non-woven cloth. The sheet material can be used for packaging or to form containers. An example of a sheet is known as hamburger bun material. This is a thin, water-resistant packaging that is often misunderstood by consumers as being prone to degradation and discarded. Another example is molded containers, or containers that are folded and glued, such as food cartons for transporting take-out food. Other examples include product packaging for general retail sale. Advantageously, the compositions disclosed herein can be heat sealed to form a hermetic container or package.

Preferably, the sheet-like material has an average thickness of 100 to 500 microns, preferably 200 to 400 microns.

According to one embodiment, the sheet material has an expanded gas-containing structure. That is, the sheet material can be provided with internal voids that are trapped, which provides the benefit of insulation for the user. For expanded materials, the thickness may preferably be from 1000 microns to 10 cm.

According to a further aspect, there is provided a package or container formed from the sheet material described herein.

According to a further aspect, there is provided a disposable coffee cup formed from the sheet material described herein, optionally further comprising a component selected from the group consisting of a lid, a handle, and a sleeve, wherein the component Also formed from this degradable composition.

Disposable coffee cups are suitable containers for holding single-serve beverages from which a consumer can sip. Typically, such containers will have a volume of from 30ml to 11 (1 liter), more typically from 200 to 350ml. The container is suitable for hot beverages at temperatures up to 100°C, however peak temperatures in general use are only 80 to 95°C. Thus, the container is waterproof for the period of intended use (ie, at least 1 day). Coffee mugs are disposable, meaning they are expected to be thrown away after use rather than reused for other beverages. The container has an opening through which the container can be filled and emptied.

A typical coffee cup is a hollow frustroconical body having a base with a narrower diameter (eg 3 to 8 cm), a wider diameter at the top/spout (eg 5 to 10 cm), and a height of eg 5 to 15cm. The general weight of a coffee cup is 5 to 20 grams, usually about 10 to 12 grams.

Preferably, the cup has a wall thickness of 100 to 500 microns, preferably 200 to 400 microns.

According to one embodiment, the composition has an expanded gas-containing structure. That is, the cup wall may be provided with trapped internal voids which provide the insulating benefit to the cup wall, thereby preventing the user from scalding his hands on the hot beverage. For expanded cups, the wall thickness may be from 400 to 3000 microns, preferably from 1000 to 2000 microns.

According to another aspect, an additive formulation is provided for forming the degradable polymer compositions described herein when added to a polymer comprising one or more polyolefins, the additive formulation comprising two or more transition metal compounds, mono- or polyunsaturated _C14 - _C24 carboxylic acids, synthetic rubbers and phenolic and/or phosphite antioxidant stabilizers, and optionally dry starch and/or calcium oxide, and Wherein the additive formulation further includes a carrier polymer for dilution in polyolefin, the amount is 1-20wt% of the additive formulation in the degradable polymer composition, preferably 1-4wt%.

According to another aspect, there is provided a method for forming a degradable polymer composition as described herein, the method comprising: (i) hot extruding a carrier polymer, two or more Transition metal compound, mono- or polyunsaturated _C14 - _C24 carboxylic acid, synthetic rubber and phenolic and/or phosphite antioxidant stabilizer, and optionally calcium oxide, forming the additives described herein (ii) optionally adding starch; (iii) blending the additive with a polymer comprising one or more polyolefins to form an additive comprising 1 to 20 wt % (preferably 1 to 4 wt % % additives) blends.

Preferably, the method also includes: (iv) blending additives and/or polymers comprising one or more polyolefins with calcium carbonate to provide 30 to 80 wt% calcium carbonate, based on the weight of the degradable polymer composition.

According to another aspect, there is provided a method of forming a container, the method comprising: forming a composition comprising 30 to 80% by weight of calcium carbonate, additives and polymers, shaping the composition to form a container, wherein the polymer and additives are as described herein.

According to another aspect, there is provided a method of forming a disposable coffee cup, the method comprising: forming a composition comprising 30 to 80% by weight of calcium carbonate, additives and polymers, shaping the composition to form a coffee cup, wherein the polymer and additives are as described herein.

In the foregoing embodiments, the step of forming generally includes mixing the ingredients, optionally with additives provided in the masterbatch concentrate composition, to form the composition.

Preferably, the step of shaping the composition to form a container or coffee cup comprises molding the composition into a container configuration, or forming and shaping one or more pieces of the composition into a container configuration, And optionally, fixing the configuration with heat sealing or gluing, or 3D printing, as appropriate.

Preferably, shaping is performed by molding methods such as thermoforming, injection molding, injection blow-molding or compression molding. Shaping can alternatively include folding techniques. This can include pressure heat sealing. Advantageously, due to the polymer content, this can be achieved without the use of adhesives.

Preferably, the method is used to make the container or coffee cup detailed above.

Primary degradation/decomposition as described herein is preferably between 2 and 6 weeks and this can be demonstrated in fugitive (roadside, wasteland), soil and aerobic composting environments. Generally speaking, primary degradation compromises the structural integrity of the container such that it is no longer fit for its original purpose. If the sheet material is in an environment with suitable microorganisms, the microbial digestion time of the material will be increased from 6 months to 1 year. Degraded material will turn into a white chalky powder.

According to another aspect, there is provided the use of an additive for initiating degradation of a sheet material (or coffee mug) comprising said additive after exposure to temperatures exceeding 50° C., wherein the additive and sheet material composition is such as described in this article. Preferably, the exposure to temperatures in excess of 50°C comprises contacting the sheet material with hot beverage or food, or exposing the sheet material (or coffee mug) to microwave heating.

The composition of the present invention seeks to solve the problem of disposal of improperly handled packaging and containers such as coffee mugs. When consumers trust their containers to be recyclable, it is advantageous for the present invention to provide a recycled material that can be included in standard recycling programs because the components are compatible with other recycled materials. Advantageously, the present invention provides a degradable material that degrades rapidly under such conditions when consumers believe that their containers are only made of paper and will naturally degrade if discarded in a ditch.

Examples of specific applications for the sheet-form materials discussed herein include paperboard, cartons for food/beverages, wrapping paper, food labels, gardening/agricultural labels, straws, business cards, gift boxes, and paper-like bags. These are particularly suitable for cast films. Other applications include disposable tableware, disposable containers such as flower pots, yogurt jars, food-to-go containers, and hot/cold beverage lids, which can be produced using thermoforming technology. Other applications include compostable carrier bags, garbage bags, seed/grain bags, cement bags, and silage packaging, as well as food packaging such as burger sheets, all of which can be made from blown film. The intumescent composition can be employed to include single use insulated beverage/food containers, packaging materials, insulation, temporary plastic seats, bicycle seats or bicycle helmets. Advantageously, the material can be easily printed on.

All percentages used in this disclosure are by weight unless otherwise specified.

For the avoidance of doubt, examples of relative quantities are provided. In a composition comprising 50wt% of calcium carbonate, 1wt% of additives, and the rest (49wt%) of polymers, the composition of 0.5wt% of additives based on the total weight of polymers and additives accounts for the overall composition 0.25wt%.

The invention will now be described with reference to the following non-limiting examples.

example

Exemplary sheet formulations are described below.

Exemplary recipes for thermally formed NMP products

Sheets for forming containers (coffee cups) prepared from polyolefin compositions comprising HDPE or PP, copolymers or blends of PE/PP, having a melt flow index of 10-30 g/10 min , and contains calcium carbonate with a particle size of 1 to 30 microns. To this is added a masterbatch additive formulation (0.2-5%) comprising a mixture of metal stearates, carboxylates, calcium oxide, metal carbonates, dry starch and unsaturated rubber. Carbon black or other pigments can be added at 0.1-10% loading for coloring

Formulation Examples for Film Blown Products

Sheets for forming containers made from polyolefins comprising HDPE, LLDPE, or PP, copolymers or blends having a melt flow index of 0.2 to 2 g/10 minutes, containing particle sizes of 1 to 30 microns Calcium carbonate, and an additive formula (0.1-5%), the additive formula contains the above-mentioned mixture for metal stearates, and carbon black is added as a coloring agent.

Demonstration Formulation of Expanded PP Products

Preparation of expanded PP grade resins containing 30-50% calcium carbonate, with an average diameter of 0.1-5 microns, will contain 0.1-5% of the additives described herein, containing a mixture of dry starch, unsaturated rubber and metal catalysts . This is molded into the form of a coffee mug.

Detailed formula

The following recipe is used to form a plastic suitable for forming coffee cups by adding other HDPE or PP and calcium carbonate. Calcium carbonate accounted for 50% by weight of the mixture, while HDPE or PP accounted for 48% by weight of the mixture. In each instance, the additive formulation was added in the remaining 2 wt%. The final amount of each component of the additive is based on the total weight of the additive and polyolefin. The cup was tested under extreme climatic conditions and verified to break down quickly. In addition, the cups have a good paper feel and strength for the intended application.

Recipe 1 An additive formulation was prepared consisting of the following: i) Dry starch - 10.00 wt.% ii) Manganese Stearate - 3.00 wt.% iii) Ferric stearate - 7.00 wt.% iv) Copper stearate - 1.30 wt.% v) Irganox 1076-5.00wt.% vi) Oleic acid - 2.00wt.% vii) SIS/SI Copolymer - 4.00 wt.% viii) Calcium Oxide - 10.00 wt.% ix) LDPE-57.7wt.%

Recipe 2 An additive formulation was prepared consisting of the following: i) Dry starch - 10.00 wt.% ii) Manganese stearate - 2.00 wt.% iii) Ferric iron stearate - 10.00 wt.% iv) Irganox 1076-5.00 wt.% v) Oleic acid - 1.00wt.% vi) SIS/SI Copolymer - 2.00wt.% vii) Calcium Oxide - 10.00 wt.% viii) LLDPE-60.0 wt.%

Recipe 3 An additive formulation was prepared consisting of the following: i) Dry starch - 10.00 wt.% ii) Manganese stearate - 4.00 wt.% iii) Copper stearate - 8.00 wt.% iv) Irgaphos 168-5.00 wt.% v) Oleic Acid - 4.00 wt.% vi) SIS/SI Copolymer - 2.00wt.% vii) PP-67.0wt.%

Stearates of manganese, ferric and copper contain 3 wt% or less volatiles. Synthetic rubber free of halides and BPA.

Exemplary formulations 1, 2, and 3 were formed by hot extruding ingredients ii-viii, and then adding starch separately. By adding the starch separately, it can be added after the heating step to avoid damage to the structure.

Recipe 4 An additive formulation was prepared consisting of the following: i) Manganese Stearate - 3.00 wt.% ii) Ferric stearate - 7.00 wt.% iii) Copper Stearate - 1.30 wt.% iv) Irganox 1076-5.00 wt.% v) Oleic Acid - 4.00 wt.% vi) SIS/SI Copolymer - 4.00 wt.% vii) Calcium Oxide - 10.00 wt.% viii) LDPE-65.7wt.%

Recipe 5 An additive formulation was prepared consisting of the following: i) Manganese Stearate - 3.00 wt.% ii) Ferric stearate - 7.00 wt.% iii) Copper Stearate - 1.30 wt.% iv) Irgaphos 168-5.00 wt.% v) Oleic Acid - 2.00 wt.% vi) SIS/SI Copolymer - 4.00 wt.% vii) Calcium Oxide - 10.00 wt.% viii) PP-67.7wt%

Exemplary formulations 4 and 5 were formed by hot extrusion of the ingredients.

Although a preferred embodiment of the invention has been described in detail herein, those skilled in the art will appreciate that changes may be made therein without departing from the scope of the invention or the appended claims.

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Claims (16)

A degradable polymer composition, comprising: additives; optionally, calcium carbonate accounting for 30-80 wt% of the composition weight; and the remainder being a polymer, the polymer comprising one or more polyolefins, wherein, according to The total weight of the additive and the polymer, the additive comprising: (a) two or more transition metal compounds in a total of 0.15-0.5 wt%, the compounds containing 3 wt% or less volatiles; (b ) mono- or polyunsaturated C ₁₄ -C ₂₄ carboxylic acid, or its ester, anhydride or amide, in an amount of 0.04 to 0.16% by weight; (c) synthetic rubber, in an amount of 0.04 to 0.2% by weight, wherein the rubber Free of halides and bisphenol A (bisphenol A); (d) phenolic and/or phosphite antioxidant stabilizers in an amount of 0.01 to 0.2 wt%; and, optionally: (e ) dry starch in an amount of 0 to 10 wt%; and/or (f) calcium oxide in an amount of 0-1 wt%; and/or wherein the two or more transition metal compounds are selected from iron, manganese, copper , zinc, titanium, cobalt, and cerium compounds, and wherein the transition metals in the two or more transition metal compounds are different. The degradable polymer as described in claim 1, wherein the one or more polyolefins comprise ethylene and/or propylene monomers, and optionally further comprise compounds comprising acetate, vinyl acetate, methyl methacrylate A monomer selected from the group consisting of esters, vinyl alcohol and acrylic acid. The degradable polymer as described in claim 1 or 2, wherein the polyolefin is selected from the group consisting of: PP, LDPE, LLDPE, HDPE, MDPE, VLDPE, EVA, EVOH, EMMA and EAA. The degradable polymer according to any one of claims 1 to 3, wherein the composition comprises 60 to 70 wt% calcium carbonate. The degradable polymer as described in any one of claims 1 to 4, wherein the transition metal compound in the additive includes multiple moieties selected from stearate, carboxylate, acetylacetone acetylacetonate, triazacyclononane, or a combination of two or more of the above. The degradable polymer as described in any one of claims 1 to 5, wherein the transition metal in the two or more transition metal compounds in the additive includes: (i) iron, manganese, and copper; or (ii) manganese and copper; or (iii) Iron and manganese. The degradable polymer as described in any one of claims 1 to 6, wherein the unit or polyunsaturated C ₁₄ -C ₂₄ carboxylic acid in the additive is a C ₁₆ -C ₂₀ linear carboxylic acid, preferably oleic acid . The degradable polymer as described in any one of claims 1 to 7, wherein the synthetic rubber in the additive comprises an unsaturated polymer, preferably styrene-isoprene-styrene, more preferably benzene Blends of ethylene-isoprene-styrene and styrene-isoprene copolymers. The degradable polymer according to any one of claims 1 to 8, wherein, based on the total weight of the additive and the polymer, the additive includes: (b) two or more transition metal stearates, and/or (c) monounsaturated C ₁₆ -C ₂₀ linear carboxylic acids in an amount of 0.05 to 0.06 wt %; and/or (d) synthetic rubber in an amount of 0.08 to 0.12 wt%, and/or (e) dry starch in an amount of 0.1 to 0.4 wt%; and/or (f) calcium oxide in an amount of 0.1 to 0.3 wt%; and/or (g) phenols and / or a phosphite antioxidant stabilizer in an amount of 0.02 to 0.15 wt%; The degradable polymer as described in any one of Claims 1 to 9 is in the form of a sheet material, preferably a non-woven fabric. The degradable polymer according to claim 10, wherein the sheet material has an expanded gas-containing structure. A package or container formed from the sheet material as described in Claim 10 or Claim 11. A disposable coffee cup formed from the sheet material as claimed in claim 10 or claim 11, optionally further comprising a component selected from the group consisting of a lid, a handle, and a sleeve A group wherein the component is also formed from the degradable composition. An additive formulation for forming a degradable polymer composition as described in any one of claims 1 to 11 when added to a polymer comprising one or more polyolefins, the additive formulation comprising the two or More transition metal compounds, the mono- or polyunsaturated C ₁₄ -C ₂₄ carboxylic acid, the synthetic rubber and the phenolic and/or phosphite antioxidant stabilizer, and optionally the dry starch and / or the calcium oxide, and wherein the additive formulation further comprises a carrier polymer, and is used for dilution in polyolefin, and its amount is 1-20wt% of the additive formulation in the degradable polymer composition, preferably 1-4wt %. A method of forming the degradable polymer composition according to any one of claims 1 to 11, the method comprising: (i) by hot extruding the carrier polymer, the two or more A transition metal compound, unit or polyunsaturated C ₁₄ -C ₂₄ carboxylic acid, the synthetic rubber and the antioxidant stabilizer of the phenols and/or phosphites, and optionally the calcium oxide, to form The additive described in claim 14; (ii) optionally adding starch; (iii) blending the additive with a polymer comprising one or more polyolefins to form a polymer comprising 1 to 20 wt% A blend of the additive, preferably 1 to 4 wt % of the additive. The method as described in claim 15, wherein the method further comprises: (iv) blending the additive and/or the polymer comprising one or more polyolefins with calcium carbonate to provide 30 to 80 wt% calcium carbonate by weight of the degradable polymer composition.