PA recyclable thermoplastic blends containing poly(ethylene terephthalate)

Abstract

The recycled thermoplastic composition has improved processing characteristics and includes a laminated thermoplastic material having two or more layers, at least one of which is made of: a,i) 1,2-ethanediol (EG), a,ii) β,β,β'β'-tetramethyl-3,9-(2,4,8,10-tetraoxaspiro[5.5]undecane)diethanol (PSG), and a,iii) Benzene-1,4-dicarboxylic acid (PTA) and b) at least one layer is obtained from said laminated thermoplastic material consisting of poly(ethylene terephthalate) (PET), The thermoplastic material is flaked and possibly pelletized.The present invention also relates to laminate compositions containing recycled blended materials.

Description

[Technical Field]

[0001] The present invention relates to thermoplastic blends containing poly(ethylene terephthalate) that are recyclable and easy to process. [Background technology]

[0002] The production of various types of containers from poly(ethylene terephthalate), commonly abbreviated as PET, is well known in the art. Among the containers produced are bottles and trays. One problem with PET is that it cannot withstand the temperatures used in so-called hot-fill applications. This has historically meant that the industry was limited to glass, polycarbonate, or polystyrene, all of which are questionable from an environmental perspective. To address these shortcomings, various PET-like polymers with improved high-temperature properties have been developed. These PET-like polymers are most often used with conventional PET in so-called ABA-type laminates, where the more heat-resistant PET-like polymer forms the outer layer (A) and the conventional PET forms the core layer (B). This core layer (B) often comprises more than 60% by weight of the laminate.

[0003] One issue with these types of laminates relates to the recycling of the materials. Recycling is extremely important from an environmental perspective, as it allows high-quality materials to be reused and conserves limited resources. Typically, post-consumer laminate products are ground into flakes, thoroughly washed, melted, and formed into pellets for use in new products. Like many polymers, the polymers described herein must be dehumidified before they can be processed by injection molding or extrusion, which can lead to blistering or more serious manufacturing problems. Many known recycled materials, such as those mentioned above, are known to clump during dehumidification, rendering them unprocessable. Many of these polymers are also known to become cloudy after recycling, meaning they can only be used in packaging for new, low-end or low-cost products. Therefore, there is a strong need for polymer compositions that are easier to process or process after recycling and that have mechanical and visual properties closer to those of so-called virgin materials. Thermoplastic materials available for recycling are obtained (derived, extracted) mainly from two sources. The first source is residual material resulting from the production of vacuum-formed containers, blister packages, etc. from laminated sheet material. When several formed containers are stamped from one sheet, a significant amount of material remains. A second source worth mentioning is that obtained from existing recycling systems where end consumers can return empty containers. It can be seen that there are similarities between PET bottle recycling systems in many countries. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent Application Publication No. 2013 / 0126462 [Patent Document 2] Japanese Patent Application Publication No. 10-151628 DISCLOSURE OF THE INVENTION

[0005] Detailed Description of the Invention The present invention allows for the recycling and processing of laminated products, the resulting products having mechanical and processing properties on par with virgin materials. The present invention therefore relates to a recycled thermoplastic composition ground into palletizable thermoplastic flakes with sustainable processing properties. The present invention is characterized in that the recycled thermoplastic composition is obtained (derived) from a material comprising a laminated thermoplastic material, the laminated thermoplastic material comprising two or more layers, where at least one layer (strata stratum) is made of the following material: a,i) 1,2-ethanediol (hereinafter referred to as EG), a,ii) β,β,β'β'-tetramethyl-3,9-(2,4,8,10-tetraoxaspiro[5.5]undecane)diethanol (hereinafter referred to as PSG), and a,iii) Benzene-1,4-dicarboxylic acid (hereinafter referred to as PTA) It consists of a copolymer between b) At least one layer is obtained from a laminated thermoplastic material consisting of poly(ethylene terephthalate) (hereinafter referred to as PET).

[0006] The thermoplastic composition, originally a laminate of two different thermoplastic materials that ultimately becomes a blend of the two thermoplastic materials, has been shown to have the necessary mechanical and optical properties to be fully usable in the manufacture of new laminates, as disclosed herein.

[0007] The copolymer component a) is preferably present in the recycled thermoplastic composition in an amount ranging from 0.5 to 40% by weight.

[0008] The laminate, i.e., the material to be recycled, contains EG, PSG, PTA, and PET, and exists in the form of a mixture with PET monolayer sheet material or bottles, with the laminate material comprising 1 to 40% by weight (including part of the mixture) and the monolayer PET material comprising 60 to 99% by weight (including part of the mixture).

[0009] The recycled thermoplastic composition can be used for injection molding, extrusion and / or blow molding using the same range of processing parameters as for PET.

[0010] The present invention also relates to a thermoplastic laminate produced by coextrusion, comprising a core layer B and at least one outer layer A, the core layer B comprising at least 10% by weight of recycled thermoplastic laminate material, the recycled thermoplastic laminate material comprising at least two layers, at least one of which is made of: a,i) 1,2-ethanediol (EG), a,ii) β,β,β'β'-tetramethyl-3,9-(2,4,8,10-tetraoxaspiro[5.5]undecane)diethanol (PSG), and a,iii) benzene-1,4-dicarboxylic acid (PTA), It consists of a copolymer between b) At least one layer is derived from the laminate thermoplastic material and consists of poly(ethylene terephthalate) (PET), which is mixed with the PET and then co-extruded to form a new laminate with a copolymer of EG, PSG and PTA.

[0011] The laminate is of the ABA type, where B comprises recycled thermoplastic material and A is a copolymer consisting of EG, PSG, and PTA.

[0012] Layer A preferably constitutes 5 to 50% by weight of the laminate.

[0013] According to one embodiment of the present invention, layer A is formed from virgin material, layer B comprises (including a portion of) 0.5-10% by weight of recycled laminate material, the remainder being regular PET.

[0014] According to another embodiment of the invention, Layer B comprises 1-8% by weight of the recycled laminate material (including portions thereof), with the remainder being regular PET.

[0015] The conventional PET is suitably at least 50% by weight recycled PET, more suitably at least 75% by weight recycled PET. DETAILED DESCRIPTION OF THE INVENTION

[0016] Example of an embodiment A variety of different thermoplastic laminates of the ABA type produced by coextrusion were ground into flakes and then pelletized. The composition of layer A of the laminate is as follows: ai) 1,2-ethanediol (GE), a,ii) β,β,β'β'-tetramethyl-3,9-(2,4,8,10-tetraoxaspiro[5.5]undecane)diethanol (PSG), and a,iii) Benzene-1,4-dicarboxylic acid (PTA) It is a copolymer formed by The copolymers mentioned above are known in the market as Akestra (registered trademark of the European Union), which is available in three different qualities: Akestra (registered trademark of the European Union) 90, Akestra (registered trademark of the European Union) 100 and Akestra (registered trademark of the European Union) 110. The B layer of the laminate is formed from poly(ethylene terephthalate) (PET).

[0017] Four different recycled compositions were tested with different ranges of standard PET materials mixed with ABA laminates according to Table 1 below. These tests were conducted to simulate PET recycling, where, for example, a PET bottle can be combined with other types of PET-based laminate packaging at different levels as disclosed herein.

[0018] [Table 1] * The ABA laminate contains A=EG / PSG / PTA and B=PET.

[0019] The pellets from Samples 1, 3, and 4 were then analyzed for melting peak temperature, melting enthalpy, crystallization peak temperature, and crystallization enthalpy in comparison to 100% PET, and the results are shown in Table 2.

[0020] [Table 2]

[0021] The recycled blends had very similar properties to pure 100% PET and were shown to be processable using the same range of processing settings as PET. The recycled blends were further tested for agglomeration properties. Agglomeration is undesirable and is known to occur during the drying (dehydration) of pellets prior to manufacturing. Manufacturing processes include injection molding, extrusion, and blow molding. Any residual moisture in the pellets can cause problems during molding, the most common of which is the formation of so-called blisters.

[0022] Two containers, each 130 mm in diameter and 160 mm in height, were covered at the bottom with aluminum foil. Sample 2 (Table 1) pellets were packed into the first container to a height of 50 mm, while Sample 4 (Table 1) pellets were packed into the second container to a height of 50 mm. The tops of the pellets were then covered with aluminum foil, and immediately, 9.5 kg weights, each 125 mm in diameter, were placed on top of the foil-covered pellets, one for each container. The two containers were then placed in an oven at 210°C for 90 minutes. After this 90-minute baking period, both containers with the samples and weights were removed from the oven and allowed to cool. After the cooling period, the weights were removed, and the pellets were carefully poured out of the containers and inspected for signs of agglomeration. It was found that the sample pellets showed no tendency to agglomerate.

[0023] The above results show that any type of molded part using recycled blended materials can be processed in all common types of manufacturing without any modification of the equipment and without any risk of clogging the feeding or plasticizing units in the molding equipment.

[0024] The recycled blends were further tested for tensile strength and elongation. Tensile tests were performed according to ISO 527-2 1B to measure yield stress and strain, tensile strength, and elongation at break. The equipment used was a Zwick Z10 benchtop testing machine with a 10 kN load cell. A uniaxial extension rate of 50 mm / min was used. Measurements were performed at 23°C and 50% relative humidity (RH). Dog-bone-shaped specimens for tensile testing, ISO 527-3 Type 5, were injection molded with a thickness of approximately 4 mm. All test specimens were conditioned at 23°C and 50% RH for at least three days before measurement. Tensile test results are the average of five specimens. Samples 1–4 refer to those in Table 1, while the PET specimens in that table are the average of five specimens. * (For comparison) refers to virgin, non-recycled PET. The results are shown in Table 3.

[0025] [Table 3]

[0026] The results show that the mechanical properties of the recycled laminated thermoplastic composition according to the invention are very close to, if not identical to, virgin PET material, which indicates that the laminated thermoplastic material according to the invention is fully recyclable, which is of course very advantageous from an environmental point of view.

[0027] Samples 1-4 (Table 1) were finally tested for optical appearance. Samples 1-4 were injection molded into 2.2 mm thick plates and extruded into 0.4 mm thick plates, respectively. For comparison, samples of virgin PET material were prepared using the same processing steps. These samples were then optically evaluated for haze. No significant difference in haze was detected for the 0.4 mm plates. For the 2.2 mm plates, Sample 1 was found to be slightly less hazy than the PET, while Sample 2 was very similar to the PET. Samples 3 and 4 were found to be slightly more hazy than the PET.

Claims

1. 1. A recycled thermoplastic composition pulverized into palletizable thermoplastic flakes having sustainable processing properties, comprising: As a feature, The recycled thermoplastic composition is obtained from a material comprising a laminated thermoplastic material, the laminated thermoplastic material comprising two or more layers, wherein at least one layer comprises: a,i) 1,2-ethanediol (EG), a,ii) β,β,β'β'-tetramethyl-3,9-(2,4,8,10-tetraoxaspiro[5.5]undecane)diethanol (PSG), and a, iii) Benzene-1,4-dicarboxylic acid (PTA) and b) at least one layer is made of poly(ethylene terephthalate) (PET); Recycled thermoplastic compositions.

2. 2. The recycled thermoplastic composition of claim 1, wherein component a) of the copolymer is present in the recycled thermoplastic composition in an amount ranging from 0.5 to 40 weight percent.

3. 10. The recycled thermoplastic composition of claim 1, wherein the laminate comprises EG, PSG, PTA and PET and is in the form of a mixture with a monolayer sheet material or bottle formed of PET, the laminate material comprising 1 to 40% by weight and the monolayer PET material comprising 60 to 99% by weight of the mixture.

4. 4. The recycled thermoplastic composition of any one of claims 1 to 3, wherein the recycled thermoplastic composition is suitable for injection molding, extrusion and / or blow molding using the same range of processing parameters as for PET.

5. A thermoplastic laminate produced by coextrusion, having a core layer B and at least one outer layer A, The core layer B comprises at least 10% by weight of recycled thermoplastic laminate material, which, prior to recycling, consists of at least two layers, at least one of which is a,i) 1,2-ethanediol (EG), a,ii) β,β,β',β'-tetramethyl-3,9-(2,4,8,10-tetraoxaspiro[5.5]undecane)diethanol (PSG), and a, iii) Benzene-1,4-dicarboxylic acid (PTA) and b) at least one layer of said laminated thermoplastic material comprises poly(ethylene terephthalate) (PET); The recycled thermoplastic material is mixed with PET and then co-extruded to form a new laminate with a copolymer of EG, PSG and PTA. Thermoplastic laminate.

6. 6. The laminated thermoplastic laminate of claim 5, wherein said laminate is of A-B-A type, where B comprises said recycled thermoplastic material and A is said copolymer consisting of EG, PSG and PTA.

7. 7. A laminated thermoplastic laminate according to claim 5 or 6, wherein A constitutes 5 to 50% by weight of the laminate.

8. 8. A layered thermoplastic laminate according to any one of claims 5 to 7, wherein A is formed from virgin material and B comprises 0.5 to 10% by weight of the recycled laminate material, the remainder being normal PET.

9. 9. The laminated thermoplastic laminate of claim 8, wherein B comprises 1 to 8% by weight of the recycled laminate material, the remainder being regular PET.

10. 10. A layered thermoplastic laminate according to claim 8 or 9, wherein the regular PET is at least 50% by weight of recycled PET.

11. 10. A layered thermoplastic laminate according to claim 8 or 9, wherein the regular PET is at least 75% by weight of recycled PET.

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