NL2028924B1

NL2028924B1 - PLA articles and closed-loop recycling process

Info

Publication number: NL2028924B1
Application number: NL2028924A
Authority: NL
Inventors: Ekkehart Behage Jörn; Albert Frans Kunst Johan
Original assignee: Arapaha B V
Priority date: 2020-08-06
Filing date: 2021-08-05
Publication date: 2023-05-15
Also published as: NL2028924A

Abstract

The present invention provides an article comprising at least two, durably connected, components, each comprising at least 90 wt.% polylactic acid (PLA). The components have different forms of PLA. The invention also provides a closed-loop process for recycling such an article where the starting materials of the PLA are retrieved for re-use.

Description

Title: PLA articles and closed-loop recycling process

The present invention relates to an article comprising components of polylactic acid. It further relates to a process of recycling such an article and to a process for closed-loop recycling of poly lactic acid articles.

Introduction

Polylactic acid or polylactide (PLA) is a known polymer that is increasingly of interest in view of the fact that the starting materials come from a renewable source with a very low carbon footprint. In recent years, PLA has mainly been promoted as a biodegradable material. Studies have been done on the environmental footprint of PLA, see for instance A. Morao et al, Journal of Polymers and the

Environment, 2019. showing that the main impact of PLA production is related to agricultural feedstock production and to the manufacturing process of PLA from sugar.

Morao et all show that PLA made from virgin feedstock such as sugar cane or corn has a global warming potential (GWP) of only 0.5 kg CO: per kg PLA, thereby significantly lower than petroleum-based polymers such as for instance polyester with a GWP of 2.2 kg CO: per kg polyester.

A further reduction of the GWP is possible by using PLA waste as feedstock for new PLA, by using enhanced recycling methods such as de-polymerization.

According to Piemonte et al. J. Polym. Environ (2013), 21:840-647 using such recycling methods the GWP can further be reduced to only 27 % of the GWP of PLA made out of virgin feedstock.

Application of PLA was traditionally limited due to its limited mechanical properties and therefore focused on its biodegradability. PLA was used predominantly in single use objects such as cups and plates. The biodegradability of PLA is subject to debate. Depending on the type of PLA used, the degradability takes significantly longer than the time available for composting in industrial compositing facilities (typically no more than 11 days, see Molenveld and van der Zee, Wageningen Food & Biobased Research report “The fate of (compostable) plastic products in a full scale industrial organic waste treatment facility treatment facility”). Typical single use applications made with PLA such as organic waste collection bags, plant pots, tea bags, fruit labels, coffee capsules and coffee pads need to be cycled through a commercial composting facility more than once to decompose to a small enough particle size to be classified as compost, while even after these multiple cycles of composting there are still remaining visible plastic components in the compost. Moreover, in this process the PLA that is degraded produces essentially water and CO:, thereby contributing to global warming, instead of reusing the value polymeric material itself.

Additionally, the positioning on the basis of biodegradability stimulates consumers to litter PLA made products in the believe that they will degrade. However, if

PLA is degraded in the environment, either in soil or sea, the degrading is so slow that even after 3 years, PLA based shopping bags are still strong enough to use, see Laville,

The Guardian 29 April 2019. The public opinion as well as industry focus has therefore shifted towards recycling, rather than biodegradation.

With recently newer PLA grades being developed, mechanical properties are boosted, and it is therefore now also possible to create high performance products from this material. However, these grades typically have a biodegradability that takes even longer than standard PLA, making it not practical or economic to biodegrade these newer grades.

Recycling of such higher performing PLA grades therefore seems the logical way forward to create a closed material loop for these high-performance products made out of PLA. In order to achieve an economically feasible recycling process, it is desirable that the products to be recycled are largely or completely made of the same material. In the case of plastics, it is desirable that the products are made of the same polymer material.

Current recycling processes are differentiated in mechanical and chemical recycling. In mechanical recycling, the products are collected, sorted, reduced in size and contaminations, such as soil or foreign objects, are removed as far as possible with washing steps. Then the products are dried, ground to flakes, homogenized and extruded to create a new granulate. The granulate may then be used to create new products. In the mechanical recycling process, contaminations in the actual polymer cannot be removed.

PLA is less suitable for traditional mechanical recycling because due to its relatively weak chemical bonds in the backbone, the PLA will start to hydrolyze during mechanical recycling. The hydrolysis reduces the length of the polymeric chain and thus the molecular weight (as measured by the intrinsic viscosity). This results in a reduction in performance of the recycled PLA, which can only be overcome by mixing in up to as much as 30 % of PLA made from virgin feedstock The recycled PLA can then only be used in lower demanding applications that require a low viscosity. Mechanical recycling also has the severe limitation that it does not cater for removal of additives, such as colorants, plasticizers, fillers, catalysts, UV scavengers, barrier materials, flame retardants, processing agents, etc. As a result, colored PLA will remain colored, with the final mix usually ending up close to black.

A further requirement for a useful and economic recycling process is that the recycling process itself results in relatively high value starting materials. Chemical recycling holds the promise to purify the broken-down polymers at molecular level, and thereby generating valuable new feedstock with sufficient economic value. Such process are already used at a commercial scale for polyamide-6 by Aquafil SpA and are currently being developed for polyester by, amongst others, CuRe Technology BV. Chemical recycling follows the same initial steps of collecting and sorting, but here the products are subjected to a de-polymerization step. In chemical recycling, de-polymerization occurs to recuperate the starting materials of the polymer. Chemical recycling for standard PLA grades has two main routes, either de-polymerization using water or alcohol to lactic acid (see for instance US20120142958 and US20120029228), or de-polymerization to lactide (see for instance US2016030311793 and US20140316097). An overview of chemical recycling of PLA is given in P. McKeown et al, Sus. Chem. 2020, 1, 1-22.

During the de-polymerization higher temperatures are needed to break down the molecular chain to end up with oligomers and/or monomers. Due to these elevated temperatures racemization occurs, shifting the D/L mix away from its original percentage, thereby moving the PLA to more amorphous low-grade PLA. So also here not always the desired performance is achieved.

It is therefore an object of the present invention to provide high performance articles that can be recycled to high value starting materials, that can be again used to create high performance materials and products. Thus, a genuine circular loop is created.

Disclosure of the invention

The present invention therefore provides an article comprising a first and a second component wherein the first and second component are durably connected; wherein the first component has a first form and comprises at least 90 wt.% polylactic acid (PLA) based on the total weight of the first component, wherein the second component has a second form and comprises at least 90 wt.% polylactic acid (PLA) based on the total weight of the second component, and wherein the first form is different from the second form.

By providing an article that is made up of different components all made of PLA, the present invention ensures that such an article can be recycled in an efficient and cost-effective way, creating a closed-loop recycling process.

According to a second aspect, the present invention provides a process of recycling an article of the invention.

According to a third aspect, the present invention provides a process for closed-loop recycling of products containing polylactic acid.

The present process ensures that the starting materials for making the

PLA are recuperated as high value starting materials suitable for re-polymerization.

Detailed description of the invention

Polylactic acid

Polylactic acid is a polymer with the repeating unit: tor

LM

Polylactic acid is obtained by polymerizing lactic acid and the cyclic d- ester, lactide. Lactic acid can be typically obtained from fermented plant starch such as from corn, cassava, sugarcane and beet pulp. Lactide results from the chemical conversion of lactic acid. Polylactic acid is thus a polymer obtained from bio renewable resources.

The most common route to PLA is the ring-opening polymerization of lactide with various metal catalysts (typically tin octoate) in solution or as a suspension.

The metal-catalyzed reaction tends to cause racemization of the PLA, reducing its stereoregularity compared to the starting material (usually corn starch). 5 Another route to PLA is the direct condensation of lactic acid monomers.

This process needs to be carried out at less than 200 °C; above that temperature, the entropically favored lactide monomer is generated. This reaction generates one equivalent of water for every condensation (esterification) step. The condensation reaction is reversible and subject to equilibrium, so removal of water is required to generate high molecular weight species. Water removal by application of a vacuum or by azeotropic distillation is required to drive the reaction toward polycondensation. Molecular weights of 130 kDa can be obtained this way. Even higher molecular weights can be attained by carefully crystallizing the crude polymer from the melt. Carboxylic acid and alcohol end groups are thus concentrated in the amorphous region of the solid polymer, and so they can react. Molecular weights of 128-152 kDa are obtainable. 9 a me Hg

HO DH dro,

BY ©

NO o feds | 9

Ht Bon

Oily DOH

PLA and its building blocks lactic acid and lactide are chiral molecules.

The different forms of lactic acid are:

oH ~ Aon Lon

OH OH OH

Lactic acid L-(+}Lactic acid D(-}Lactic acid

For lactide, 3 enantiomers exist, L (compound a below), D (compound b} and meso (compound c):

He, ONO Hila 0 9 HO ON AP 7 Y | 1

No em, oF So Nem, OF o7 ow, a b c

Polymerization of a racemic mixture of L- and D-lactides usually leads to the synthesis of poly-DL-lactide (PDLLA), which is amorphous. Use of stereospecific catalysts can lead to heterotactic PLA which has been found to show crystallinity. The degree of crystallinity, and hence many important properties, is largely controlled by the ratio of D to L enantiomers used, and to a lesser extent on the type of catalyst used. Thus, different stereospecific forms of PLA can be produced, such as PLLA (poly-L-lactic acid),

PDLA (poly-D-lactic acid) and combinations such as PLLA-b-PDLA. The level of crystallinity depends on the ratio D/L but also the distribution of the D and L monomers in the polymer chain (random, block, etc.) (see for instance “Poly(lactide) Stereocomplexes:

Formation, Structure, Properties, Degradation, and Applications”, Hideto Tsuji, Macromol.

Biosci. 2005, 5, 569-597).

By varying the rations and distribution of the different enantiomers in the polymer, polymers with a different performance can be obtained. Another key element of performance is generated by molecular chain length as this directly links to tenacity in fibers, higher viscosity in processing etc. Another way to increase the performance is to create stereospecific PLA mixes, in which a full P(D)LA chain is mixed with a P(L)LA chain, and this combination leads to a very high melting point and crystallinity as the helix shaped molecules fold into each other.

Relevant properties of PLA (including PLLA and PDLA) used in the invention are:

Glass transition temperature Tg of from 60 to 65 °C

Melting temperature Tm of 130 to 230 °C

Tensile Modulus from 2.7 to 16 GPa

Melt flow Index from 5 to 100 g/10 min (as measured at 210 °C/2.16 kg)

Molecular weight 50 to 500 kDa

Components, forms and articles

With component is meant a semi-finished product that can be used to create a finished product. With durably connected is meant that, in normal, intended use of the article the components will not disconnect, i.e. the product will remain whole. The advantage of PLA is that this connection can be a result of the properties of PLA, i.e. by melting or (ultrasonic) welding, the PLA components can be durably connected without the use of other materials than PLA for making the connection, e.g. screws and nails.

The first component and second component comprise at least 90 wt. %

PLA, preferably at least 95 wt.% PLA, more preferably at least 97 wt.% PLA. Further additives or polymers are only present in small amounts and should be selected such that they do not impact the recyclability of the PLA. Examples of further additives that can be present are colorants and plasticizers.

The article of the invention comprises at least two different forms and may thus also comprises three, four or more different forms. This will be illustrated in the examples hereafter.

As described above, in the article the components have different forms.

With forms is meant the physical appearance or structure of the component. Such a form may be selected from the group consisting of monofilaments, fibers, yarns, woven fabrics, knitted fabrics, nonwoven fabrics, films, tapes, sheets, ropes, foams, blow molded forms, thermoformed forms, injection molded forms, 3D printed forms, resins, composites and honeycombs.

A yarn is herein understood an elongated body, which may be a monofilament, being a fiber or a tape, or a multifilament yarn that comprises a plurality of fibers, i.e. at least 2 fibers. This includes spun yarn and assembled yarn. Herein fibers are understood to be elongated bodies with length dimension much greater than their transversal dimensions, e.g. width and thickness. The term fiber includes a monofilament, a ribbon, a strip or a tape and the like, and can have a regular or an irregular cross- section. The fibers may have continuous lengths, known in the art as filaments, or discontinuous lengths, known in the art as staple fibers.

The multifilament yarns can be industrial yarns, spun yarns and filament yarns.

A tape may have an aspect ratio of at least 5:1. The width of the tape may be between 1 mm and 200 mm, preferably between 1.5 mm and 50 mm. Thickness of the flat tape may be between 10 um and 200 pm.

In case of yarns comprising different filaments, one part of the filaments can comprise a PLA with properties different from the other filaments. The yarn can also be a “skin-core” type yarn, where the skin filaments and the core filaments are made of different PLA’s.

In case of tapes, the tape can be a “skin-core” tape, where the skin and core are made of different PLA’s.

A film is a thin continuous PLA material. A thicker material is referred to as a sheet. Sheets and films include unidirectional and bidirectional films and sheets.

In the above, fabrics include woven and non-woven fabrics, including tufted fabrics, felt and fabrics made from staple fibers. In the case of a woven fabric, the fabric can comprises yarns or tapes. The weft of the fabric can comprises yarns or tapes of one type of PLA, the warp of the fabric can comprise yarns of tapes of another type of

PLA. Knitted fabrics include 3D knitted fabrics.

A resin can be a used as a coating. For this form, a hot melt adhesive is preferred, which can be an amorphous PLA.

A composite may comprise reinforcing members in a matrix material. The reinforcing member or members can be a PLA fabric. Such a composite can be a UD sheet. The matrix material can be a PLA resin. The composite may also be obtained by processing a (woven) fabric of two PLA’s having different properties, resulting in a self- reinforced composite.

In a particular embodiment of the invention, the first component comprises at least 90 wt.% of a first polylactic acid (PLA1) with a melting temperature

Tm1, based on the total weight of the component, and the second component comprises at least 90 wt.% of a second polylactic acid (PLA2) with a melting temperature Tm2, based on the total weight of the component, wherein the difference between Tm1 and

Tm2 is at least 5 °C, preferably at least 10 °C.

The article is thus comprised of PLA’s with different mechanical properties giving freedom in designing the product with different forms while creating a product that still consists mainly of PLA.

According to another embodiment, PLA1 has an optical purity of more than 99% and PLA2 has an optical purity of between 85 and 99%. With optical purity is meant that the PLA contains PLLA and PDLA, wherein the optical purity refers to the wt. %PDLA in the PLA. Le. an optical purity of more than 90% means that the PLA contains less than 10% PDLA, based on the total weight of the PLA.

PLA1 and PLA2 can also differ in terms of the molecular weight or length of the polymeric chain. This can be expressed as the melt flow index or viscosity.

According to another particular embodiment of the invention, the first component comprises a first polylactic acid (PLA1) with a melting temperature Tm1, and second polylactic acid (PLA2) with a melting temperature Tm2, wherein the difference between Tm1 and Tm2 is at least 5 °C, preferably at least 10 °C; and the second component comprises a third polylactic acid (PLA3).

Such an article thus consists of one component combining properties of two different PLA’s, such as a composite material and one component comprising yet another PLA.

According to an embodiment, the article comprises a first component which is a foam and the second component is a composite. In this article, the composite can comprise the PLA1 and PLA2 as described above. According to another embodiment, the article comprises a first component which is a fabric and a second component which is a yarn.

Finished articles can include any article that can be used in daily life.

Examples of finished products include tables, chairs, baby strollers and car seats. But the article can also be a textile product such as a clothing, bathmats, rugs or carpets. Further examples of articles of the invention are kayaks and paddles, bags, lamps, surfboards and sailboats.

One embodiment of the invention is a textile product having a backing and yarns connected to or extending from the backing. Such a textile product can comprise a carpet or bathmat. The backing can be a woven or non-woven fabric as defined above.

Another embodiment is a chair wherein the first component is a foam and the second component is a composite.

Another embodiment is a paddle wherein the first component is a composite and the second component is a foam.

Further embodiments are illustrated in the Examples hereafter.

Recycling

The invention also provides a process of recycling an article as described above, comprising the steps of: grinding the article to obtain PLA particles; subjecting the PLA particles to a de-polymerization reaction; recovering and optionally purifying the depolymerized product thus obtained.

In particular, the de-polymerization reaction is a glycolysis, hydrolysis or alcoholysis reaction.

It is an object of the invention to provide a recycling process that retains as much as possible of the properties of the original starting materials of the PLA used, such that their re-use will result in similar high-performance materials. Thus, the depolymerized product comprises one or more of L-lactic acid, D-lactic acid, L-lactide, D- lactide, and the step of purifying the depolymerized product comprises a chiral separation.

The chiral separation may be carried out by means of one or more of melt crystallization, vacuum distillation, vapor distillation, membrane separation and chromatography.

Processes for chiral separation are for instance described in WO2015074827,

US5,264,592, WO2000056693, EP3406605 and WO2016174161.

As described above, one of the main benefits of the invention is that it provides for a closed loop recycling of products containing polylactic acid. This means that after use of the article, the article can be treated such that the original starting materials are recovered.

Such a closed loop recycling process comprises the steps of: « polymerizing starting materials selected from one or more of L-lactic acid, D- lactic acid, L-lactide and D-lactide, to create polylactic acid (PLA); + producing a first form comprising at least 90 wt.% polylactic acid and a second form comprising at least 90 wt.% polylactic acid, wherein the first form is different from the second form; + producing a first component from the first form and a second component from the second form; + connecting the first component and the second component to produce an article; + after use, subjecting the article to a recycling process such that the starting materials are recuperated in an amount of at least 90 mol. % of their original chemical configuration (L-lactic acid, D-lactic acid, L-lactide, D-lactide).

Further steps in the closed loop recycling process may include one or more of: + collecting the articles « initial sorting of the articles + blending and detailed sorting: removal of all other polymers and contamination + homogenization: preparation for stable infeed + extrusion: infeed, preheat, compounding, degassing, contamination removal « reactive extrusion: water and/or alcohol (glycol)dosing, possibly addition of a de-polymerisation catalyst, contamination removal + filtration: removal of particle and inorganic pigments such as titanium dioxide (white) and carbon black (black) + decoloration: removing remaining color, e.g. via distillation + removing other contaminants via distillation + supplementation of the lactic acid obtained with L- or D-lactic acid to obtain the desired L/D lactic acid ratio

Examples

Materials

Composite

A fabric is used (BIO4M® srPLA from COMFIL), made by weaving commingled yarns {composite yarn) with 50% continuous reinforcement fibers and 50% continuous matrix fibers. The melting point of the matrix fibers is about 150°C. The reinforcement fibers are made of high tenacity PLA with a melting point of about 175 °C.

These fabrics can easily be consolidated in a different process, by heating the material above the melting point of the actual matrix materials, e.g. to a temperature of around 150-165 °C.

Tape

Tapes are produced by drying a PLA neat resin to reduce residual moisture. This dried PLA resin is subsequently extruded as a film, which after slitting resulted in tapes that can be wound on a bobbin for further processing. Drying is carried out according to supplier instructions: “PLA must be dried to <250 parts per million (ppm) moisture and maintained at this moisture level to minimize hydrolysis during melt processing. The PLA should be dried at 65-90°C using dehumidified air with a dew point of -40°C".

The choice of PLA grade for tape production depends on the application.

If the tape is subsequently woven into tape fabric, especially the weft tape needs to have an as high as possible tenacity to reduce tape breaking due to the friction with the warp tapes inside the weaving loom. For the warp tape this is less essential and a PLA resin with a more forgiving melt flow index can be used to increase the production speed. For example the warp tape can be produced using Total Corbion’s PLA grade Luminy® L130 with a melt flow index (MFI, Flow, 210°C/2.16 kg) of 23 g per 10 minutes resulting in a tenacity of around 0.35 cN/dTex, whereas for the weft tape this can be produced using

Total Corbion’s PLA grade Luminy® L175 with a melt flow index (MFI, Flow, 210°C/2.16 kg) of only 8 g per 10 minutes resulting in a tenacity of around 0.40 cN/dTex.

A typical titer of the tapes is 110 dtex (110 g/10.000 meter). Width of the tape is less than 2 mm.

Yarn

PLA is melt spun to obtain a multifilament yarn of about 25 tex using a spin pilot with one yarn from Fourné Maschinenbau GmbH, Alfter-Impekoven.

Multifilament yarns are obtained of two types of PLA, with different melting points (high and low). Using an air texturizer machine (DP5-T) from SSM Schärer Schweiter Mettler

AG, Horgen, a hybrid yarn is produced of the two types of multifilament PLA, having 50% high Tm PLA and 50 % low Tm PLA multifilament yarn.

Blow molded tube

The yarns obtained above are used to make a tubular braid. The tubular braid is submitted to a bladder inflation molding process to obtain a solid tube.

The different forms of PLA can further be readily produced by a person skilled in the art, or can be obtained commercially. For instance, staple fiber from Trevira,

Germany; spunbond PLA from Fitesa Germany, BCF yarns from Beaulieu, Belgium; blown film from Nurel, Spain; foam from Novipax, USA; injection molded PLA from Florida, Italy; twisted yarns, from Korteks, Turkey; monofilament from Perlon Nextrusion Monofil,

Germany and Sioen Industries, Belgium.

Example 1 Chair

A chair is produced that consists of the following PLA components: 1) Bucket (shell), made of PLA hybrid composite 2) Inside seat, made of PLA foam 3) Upholstery, made of PLA fabric 4) Joint, made of injection molded PLA 5) Legs, made of blow molded PLA tubular braids, filled with PLA foam.

Example 2 Bathmat

A bathmat is produced that consists of the following PLA components: 1) A primary backing made of woven PLA tapes or fibers, nonwoven PLA fabric or a combination thereof 2) Tufted or loop yarns or filaments (spun yarn or bulk continuous filament (BCF))

3) Coating made of PLA foam, or coating created by extrusion or hot melt coating

An example of a hot melt coating is Natureworks as Vercet A1010X, A1020X or A1030X containing plasticizers at around 10 to 15 %.

Quantity is 10 % preferably 15 % of a hot melt coating between 300 g/m2 to 1500 g/m2.

Example 3 Paddle

A paddle is produced that consists of the following PLA components 1) Blade made of PLA composite 2) Filling of the blade, made of 3D printed PLA 3) Paddle stick/handle made of blow molded PLA tubular braids

The paddle is packaged in a carrying bag that contains PLA fabric and a stuffing of PLA staple fiber.

Example 4 Bag

A bag is made of PLA fabric and a padding of PLA staple fiber, sown together with PLA yarn or monofilament.

Example 5 Polo shirt

A polo short is made of a PLA fabric and buttons of PLA, sown together with PLA yarn.

Further examples of products of the invention, are shown in Table 1, below.

Table 1

Produet [| Componentl [Component2 | Component 3

Table Honeycomb tabletop, film / foil to laminate | Film Honeycomb Composite Leg the honeycomb, composite legs, injection molded connections, foam for edge protection

Chair, baby stroller, 3D formed composite for the shell, foam for | Composite Foam Fabric car seat the seat, woven fabric for the textile covering, injection molded connections, legs and tubes from composite fibers molded into a tube

Bath matt, rug, carpet | Fibers (spun yarn, BCF fibers, tapes), tuft Yarn Fabric cloth (on woven or woven tapes (possibly skin-core tapes), foam or coating to hold it all together, monofilament for sewing the edges, woven filament yarn for the labels

Kayak & Paddle 3D shaped composite, foam, possibly Composite Foam laminated textile to close the manhole, ropes for mooring

Bag Woven fabric, knitted fabrics, sewing Rope Fabric Yarn thread, foam to fill the textile for protection, sheet for solidity in the bottom of the bag, ropes for the handles

Lamp Injection molding + pultruded tube out of Injection Composite fibers with low / high melting point, moulded part composites, connections injection molded

Sailboat Composites tubes as masts, foam with Composite Rope Fabric composites as impact protection, ropes for mooring, laminated textiles as sail and manhole coverings, injection molded connections

Clothing Woven fabric, knitwear combined with Woven fabric Monofilament monofilament as sewing thread, woven filament labels

SIO | sedine orien eeton (Poem joomeeste molded fins

TE | wishes as coset [even abe [For with skin/core fibers

Claims

CONCLUSIONS

1. Article comprising a first and a second component, wherein the first and second components are permanently connected to each other; wherein the first component is in a first form and comprises at least 90 wt% polylactic acid (PLA) based on the total weight of the first component, wherein the second component is in a second form and at least 90 wt% polylactic acid (PLA) lactic acid (PLA) based on the total weight of the second component and wherein the first form differs from the second form.

The article of claim 1, wherein the first form is selected from the group consisting of monofilaments, fibers, yarns, woven fabrics, knitted fabrics, nonwoven fabrics, films, tapes, sheets, ropes, foam, blow molding, thermal molded molds, injection molds, 3D printed molds, resins, composites and honeycombs; the second form is selected from the group consisting of monofilaments, fibers, yarns, woven fabrics, knitted fabrics, non-woven fabrics, films, tapes, sheets, ropes, foam, blown molds, thermoformed molds, injection molded, 3D -print molds, resins, composites and honeycombs.

An article according to any one of the preceding claims, wherein the first component comprises at least 90% by weight of a first polylactic acid (PLA1) having a melting temperature, Tm1, based on the total weight of the component, the second component at least 90 % by weight of a second polylactic acid (PLA2) having a melting temperature, Tm2, based on the total weight of the component and wherein the difference between Tm1 and Tm2 is at least 5°C, preferably at least 10

°C.

The article of claim 3, wherein PLA1 has an optical purity greater than 99% and PLA2 has an optical purity between 85 and 99%.

The article according to claim 1 or 2, wherein the first component comprises a first polylactic acid (PLA) with a melting temperature Tm1 and a second polylactic acid (PLA2) with a melting temperature Tm2, the difference between Tm1 and Tm2 being at least 5°C , preferably at least 10°C; and wherein the second component comprises a third polylactic acid (PLA3).

An article according to any preceding claim wherein the first component is a foam and the second component is a composite.

An article according to claim 6 which is a chair or a toad.

The article of any one of claims 1 to 5, wherein the first component is a fabric and the second component is a yarn.

An article according to claim 8 which is a bath mat, rug or textile product.

An article recycling method according to any one of the preceding claims comprising the steps of: grinding the article to obtain PLA particles; subjecting the PLA particles to a depolymerization reaction; recovering and optionally purifying the depolymerized product thus obtained.

The method of claim 10, wherein the depolymerization reaction is a glycolysis, hydrolysis or alcoholysis reaction.

The method of claim 10 or 11, wherein the depolymerized product comprises one or more of L-lactic acid, D-lactic acid, L-lactide, D-lactide and the purification step of the depolymerized product comprises a chiral resolution.

The method of claim 12, wherein the chiral separation is performed by one or more of melt crystallization, vacuum distillation, vapor distillation, membrane separation, and chromatography.

14. Process for closed-loop recycling of products containing polylactic acid, comprising the steps of: + polymerizing starting materials selected from one or more of L-lactic acid, D-lactic acid, L-lactide and D-lactide to make polylactic acid (PLA); e producing a first form comprising at least 90% polylactic acid by weight and a second form comprising at least 90% polylactic acid by weight, the first form being different from the second form; e producing a first component from the first mold and a second component from the second mold; + connecting the first component and the second component to produce an article; e subject the article to a recycling process after use, so that the starting materials are recovered in an amount of at least 90 mol% of their original chemical composition (L-lactic acid, D-lactic acid, L-lactide, D-lactide).

The method of claim 14, wherein the recycling method is the method of any one of claims 8 to 11.