Recyclable hot melt adhesive copolyester composition

Abstract

Adhesive compositions made from a blend of copolyester compositions comprising residues of terephthalic acid, 1, 4-cyclohexanedimethanol (CHDM), ethylene glycol (EG), neopentyl glycol (NPG), and / or 2, 2, 4, 4-tetramethyl-1, 3-cyclobutanediol (TMCD), having certain advantages and improved properties, including recoverability, over certain ranges of compositions.

Description

Technical Field

[0001] The present disclosure relates to a hot melt adhesive composition made from a blend of copolyester compositions, the copolyester compositions comprising residues of terephthalic acid, 1,4 - cyclohexanedimethanol (CHDM), ethylene glycol (EG), neopentyl glycol (NPG) and / or 2,2,4,4 - tetramethyl - 1,3 - cyclobutanediol (TMCD), having certain advantages and improved properties, including recyclability, within certain compositional ranges. Background Art

[0002] Historically, hot melt adhesive compositions used in packaging applications have been made from polyolefin materials, and the packaging containers in these applications have been made from polymers such as polypropylene (PP), high - density polyethylene (HDPE) or styrene. However, the packaging industry is currently moving towards making these types of containers recyclable in the PET stream or giving them recycle content. This trend is due to the requirement to increase the recycle content in packaging articles and / or make them more recyclable to avoid landfilling or incineration. Thus, there is a shift towards making these containers from polyesters that are recyclable in the PET stream rather than from other polymers such as polypropylene (PP) or high - density polyethylene (HDPE) and styrene that are not recyclable in the PET stream. There is also a need for adhesives used on these containers to be made from polymers that are recyclable in the PET stream, particularly RIC - 1 compatible.

[0003] In the present disclosure, it has been found that polyester compositions can be used with adhesives made from RIC - 1 compatible copolyester compositions instead of polyolefin - based adhesives.

[0004] The present disclosure addresses a long - standing commercial need for hot melt adhesives produced from copolyester compositions having the following desired properties: (1) good adhesion strength, (2) good processability, (3) good peel force, and (4) RIC - 1 compatibility. It is also desirable that these adhesive compositions be made from materials that can be easily recycled, contain recycled materials, and / or be made from materials not considered environmentally harmful (either as raw materials or as the final polymer materials such as styrene, polystyrene, polyolefins, etc., as in the case of the disclosed copolyester compositions). Summary of the Invention

[0005] One aspect of the present disclosure is an adhesive composition comprising a copolyester blend, the copolyester blend comprising:

[0006] A) 25 wt% - 75 wt% of at least one copolyester composition, the copolyester composition comprising:

[0007] (a) A dicarboxylic acid component, said dicarboxylic acid component comprising:

[0008] (i) 85 to 100 mole % of terephthalic acid residues, and

[0009] (ii) 0 to 15 mole % of aromatic and / or aliphatic dicarboxylic acid residues having up to 20 carbon atoms; and

[0010] (b) A diol component, said diol component comprising:

[0011] (i) 0 to 15 mole % of residues of 2,2,4,4 - tetramethyl - 1,3 - cyclobutanediol (TMCD); 1,4 - cyclohexanedimethanol (CHDM) residues; NPG residues and DEG residues, one or more of which, whether formed in situ or not; and

[0012] wherein the remainder of said diol component comprises:

[0013] (ii) Residues of ethylene glycol, and

[0014] (iii) Optionally, 0 to 10 mole % of residues of at least one other modified diol;

[0015] wherein the total mole % of said dicarboxylic acid component is 100 mole %, and wherein the total mole % of said diol component is 100 mole %; and

[0016] B) 75 wt% - 25 wt% of at least one copolyester composition, said copolyester composition comprising

[0017] (a) A dicarboxylic acid component, said dicarboxylic acid component comprising:

[0018] (i) 85 to 100 mole % of terephthalic acid residues, and

[0019] (ii) 0 to 15 mole % of aromatic and / or aliphatic dicarboxylic acid residues having up to 20 carbon atoms; and

[0020] (b) A diol component, said diol component comprising:

[0021] (i) 20 to 50 mole % of DEG residues; and

[0022] (ii) 50 to 80 mole % of ethylene glycol (EG) residues, and

[0023] (iii) Optionally, 0 to 10 mole % of residues of at least one other modified diol;

[0024] wherein the total mole % of the dicarboxylic acid component is 100 mole %, and wherein the total mole % of the diol component is 100 mole %.

[0025] In one embodiment, the copolyester blend has a melting temperature (T m ) of 190 °C - 255 °C.

[0026] In one embodiment, the copolyester blend has a Tg of 50 °C or higher.

[0027] In one embodiment, the copolyester blend has an intrinsic viscosity of 0.60 to 1.0 dL / g.

[0028] In one embodiment, the copolyester blend gives the adhesive composition a peel strength of 1 - 15 N.

[0029] In one aspect, the adhesive composition of the present disclosure can be recycled in a PET recycling stream. Detailed Description

[0030] The present disclosure can be more readily understood by reference to the following detailed description of certain embodiments and working examples of the present disclosure. For the purposes of the present disclosure, certain embodiments of the present disclosure are described in the Summary of the Invention and are further described below. In addition, other embodiments of the present disclosure are also described herein.

[0031] In a form-fill-seal package, there are three components: a bottom tray, a lid film, and an adhesive layer. There is a copolyester composition that is a RIC-1 compatible material, and the copolyester composition provides the bottom tray and the lid film. The present disclosure provides an adhesive layer composition that is also RIC-1 compatible. The compositions of the present disclosure will enable a single-material package, where the entire package, the bottom tray, the lid film, and the adhesive layer can all be recycled in a PET recycling stream.

[0032] The adhesive composition of the present disclosure is a copolyester blend that comprises Component A:

[0033] A) 25 wt% - 75 wt% of at least one copolyester composition, the copolyester composition comprising:

[0034] (a) A dicarboxylic acid component, the dicarboxylic acid component comprising:

[0035] (i) 85 mole % to 100 mole % of terephthalic acid residues, and

[0036] (ii) 0 mole % to 15 mole % of aromatic and / or aliphatic dicarboxylic acid residues having up to 20 carbon atoms; and

[0037] (b) A diol component, the diol component comprising:

[0038] (i) 0 to 15 mol% of residues of 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD); residues of 1,4-cyclohexanedimethanol (CHDM); residues of NPG; and residues of DEG, one or more of which, whether formed in situ or not; and

[0039] wherein the remainder of said diol component comprises:

[0040] (ii) residues of ethylene glycol, and

[0041] (iii) optionally, 0 to 10 mol% of residues of at least one other modified diol;

[0042] wherein the total mol% of said dicarboxylic acid component is 100 mol%, and wherein the total mol% of said diol component is 100 mol%; and Component B:

[0043] B) 75 wt% - 25 wt% of at least one copolyester composition, said copolyester composition comprising

[0044] (a) a dicarboxylic acid component, said dicarboxylic acid component comprising:

[0045] (i) 85 to 100 mol% of terephthalic acid residues, and

[0046] (ii) 0 to 15 mol% of aromatic and / or aliphatic dicarboxylic acid residues having up to 20 carbon atoms; and

[0047] (b) a diol component, said diol component comprising:

[0048] (i) 20 to 50 mol% of DEG residues; and

[0049] (ii) 50 to 80 mol% of ethylene glycol (EG) residues, and

[0050] (iii) optionally, 0 to 10 mol% of residues of at least one other modified diol;

[0051] wherein the total mol% of said dicarboxylic acid component is 100 mol%, and wherein the total mol% of said diol component is 100 mol%; and wherein said copolyester blend has a melting temperature (T m ).

[0052] In one aspect, the present disclosure relates to copolyester hot melt adhesive compositions that are recyclable in PET streams. In 2017, California Assembly Bill No. 906 - Beverage containers: polyethylene terephthalate was signed into law, and for the purpose of resin code labeling, it defines "polyethylene terephthalate" (PET) as a plastic that meets certain conditions, including limitations on the chemical composition of the polymer and the melt peak temperature within a specified range. AB - 906 added Section 18013 to the California Public Resources Code, which reads in part as follows:

[0053] "Polyethylene terephthalate (PET)" means a plastic resulting from the reaction between terephthalic acid or dimethyl terephthalate and monoethylene glycol, and simultaneously meeting the following two conditions:

[0054] a. The terephthalic acid or dimethyl terephthalate and monoethylene glycol that react account for at least 90% of the monomer mass that reacts to form the polymer.

[0055] b. The plastic exhibits a melt peak temperature between 225 degrees Celsius and 255 degrees Celsius, as determined using Procedure 10.1 as described in ASTM International (ASTM) D3418 during a second heat scan, where the heating rate of the sample is 10 degrees Celsius per minute."

[0056] Thus, copolyesters and the above blends that meet the two conditions listed in AB - 906 can be accepted as "PET", and thus such materials may be compatible with current PET recycling streams. The melting points of the blend compositions in the present disclosure make them acceptable as PET according to this definition and thus compatible with current PET recycling streams.

[0057] During the recycling process, it is necessary to dry the PET flakes to remove the residual water that remains with the PET during the recycling process. Typically, PET is dried at temperatures above 150 °C. At those temperatures, typical copolyester resins will soften and become sticky, often forming agglomerates with the PET flakes. These agglomerates must be removed before further processing. These agglomerates reduce the yield of PET flakes in the process and create additional processing steps.

[0058] In addition, it has been found that certain combinations of diol monomers in the resin composition can produce compositions and articles having good performance characteristics and that are also crystallizable such that they do not interfere with the recycling of PET flakes. These compositions and articles can be processed with recycled PET and ultimately become components in the recycled PET flakes exiting the recycling process.

[0059] As used herein, the term "container" is understood to mean a receptacle for containing or storing materials. Containers include, but are not limited to, trays, bottom trays, food trays, bakeable food trays, bottles, bags, vials, tubes, cans, and jars. Applications of these types of containers in industry include, but are not limited to, medical, automotive, food, beverage, cosmetic, and personal care applications.

[0060] In one aspect, the containers and bottles described herein can be used in a variety of applications such as food storage, food packaging, bakeable food containers and packaging; cosmetics, including beauty products, liquids, and creams; personal care; household detergents; hair care products, including shampoos and conditioners; cleaning supplies; lotions; soaps; automotive fluids, including oils and antifreeze; food and cooking supplies, including olive oil, spices, cooking oils, vegetable oils, soups, sauces, creams, and seasonings; beverages; sports drinks; water bottles; fruit juices; and milk.

[0061] As used herein, the term "polyester" is intended to include "copolyester" and is understood to mean a synthetic polymer prepared by the reaction of one or more difunctional carboxylic acids and / or polyfunctional carboxylic acids with one or more difunctional hydroxy compounds and / or polyfunctional hydroxy compounds (e.g., branching agents). Generally, the difunctional carboxylic acid can be a dicarboxylic acid, and the difunctional hydroxy compound can be a dihydric alcohol, such as a glycol and a diol. As used herein, the term "glycol" includes, but is not limited to, diols, glycols, and / or polyfunctional hydroxy compounds, such as branching agents. Optionally, the difunctional carboxylic acid can be a hydroxycarboxylic acid, such as p-hydroxybenzoic acid, and the difunctional hydroxy compound can have an aromatic nucleus with two hydroxy substituents, such as hydroquinone. As used herein, the term "residue" means any organic structure incorporated into the polymer by the polycondensation and / or esterification reaction of the corresponding monomer. As used herein, the term "repeat unit" means an organic structure having a dicarboxylic acid residue and a glycol residue bonded by an ester group. Thus, for example, the dicarboxylic acid residue can be derived from a dicarboxylic acid monomer or its related acyl halide, ester, salt, anhydride, and / or mixtures thereof. Further, as used herein, the term "diacid" includes polyfunctional acids, such as branching agents. Thus, as used herein, the term "dicarboxylic acid" is intended to include dicarboxylic acids and any derivatives of dicarboxylic acids that can be used in the reaction process with glycols to prepare polyesters, including their related acyl halides, esters, half-esters, salts, half-salts, anhydrides, mixed anhydrides, and / or mixtures thereof. As used herein, the term "terephthalic acid" is intended to include terephthalic acid itself and its residues, and any derivatives of terephthalic acid that can be used in the reaction process with glycols to prepare polyesters, including their related acyl halides, esters, half-esters, salts, half-salts, anhydrides, mixed anhydrides, and / or mixtures thereof or their residues.

[0062] The polyesters used in the present disclosure can generally be prepared from dicarboxylic acids and diols, which react in substantially equal proportions and are incorporated into the polyester polymer as their corresponding residues. Thus, the polyesters of the present disclosure can contain substantially equimolar proportions of acid residues (100 mol%) and diol (and / or polyfunctional hydroxy compound) residues (100 mol%), such that the total number of moles of repeating units equals 100 mol%. Accordingly, the mole percentages provided in the present disclosure can be based on the total number of moles of acid residues, the total number of moles of diol residues, or the total number of moles of repeating units. For example, a polyester containing 10 mol% isophthalic acid based on the total acid residues means that the polyester contains 10 mol% isophthalic acid residues in a total of 100 mol% of acid residues. Thus, there are 10 moles of isophthalic acid residues per 100 moles of acid residues. In another example, a polyester containing 25 mol% 1,4-cyclohexanedimethanol based on the total diol residues means that the polyester contains 25 mol% 1,4-cyclohexanedimethanol residues in a total of 100 mol% of diol residues. Thus, there are 25 moles of 1,4-cyclohexanedimethanol residues per 100 moles of diol residues.

[0063] In certain embodiments, terephthalic acid or its ester (e.g., dimethyl terephthalate) or a mixture of terephthalic acid residues and their esters can form part or all of the dicarboxylic acid component used to form the polyesters useful in the present disclosure. In certain embodiments, terephthalic acid residues can form part or all of the dicarboxylic acid component used to form the polyesters useful in the present disclosure. For the purposes of the present disclosure, the terms “terephthalic acid” and “dimethyl terephthalate” can be used interchangeably herein. In one embodiment, dimethyl terephthalate is part or all of the dicarboxylic acid component used to prepare the polyesters useful in the present disclosure. In embodiments, a range of 70 mol% to 100 mol%; or 80 mol% to 100 mol%; or 90 mol% to 100 mol%; or 99 mol% to 100 mol%; or 100 mol% of terephthalic acid and / or dimethyl terephthalate and / or mixtures thereof can be used.

[0064] In addition to terephthalic acid, the dicarboxylic acid component that can be used for polyester of the present disclosure can also include 30 mol %, 20 mol %, 10 mol %, 5 mol % or 1 mol % at most of one or more modified aromatic dicarboxylic acids. Another embodiment contains 0 mol % of modified aromatic dicarboxylic acid. Therefore, if present, it is expected that the amount of one or more modified aromatic dicarboxylic acids can be within the scope of any one of these aforementioned endpoint values, for example, the scope includes 0.01 mol % to 10 mol %, 0.01 mol % to 5 mol % and 0.01 mol % to 1 mol %. In one embodiment, the modified aromatic dicarboxylic acids that can be used for the present disclosure include but are not limited to those with up to 20 carbon atoms, and can be linear, para-oriented or symmetrical. Examples of modified aromatic dicarboxylic acids useful in the present disclosure include, but are not limited to, isophthalic acid, 4,4'-biphenyl dicarboxylic acid, 1,4-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 2,7-naphthalene dicarboxylic acid, and trans-4,4'-stilbene dicarboxylic acid and their esters. In one embodiment, the modified aromatic dicarboxylic acid is isophthalic acid.

[0065] The carboxylic acid component that can be used for polyester of the present disclosure can further be modified with up to 10 mol %, such as up to 5 mol % or up to 1 mol % of one or more aliphatic dicarboxylic acids containing 2-16 carbon atoms, for example cyclohexanedicarboxylic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid and / or dodecanedioic acid dicarboxylic acid. Some embodiments can also include 0.01 mol % to 10 mol %, such as 0.1 mol % to 10 mol %, 1 mol % to 10 mol %, 5 mol % to 10 mol % of one or more modified aliphatic dicarboxylic acids. Another embodiment contains 0 mol % of modified aliphatic dicarboxylic acids. The total mole % of dicarboxylic acid component is 100 mol %. In one embodiment, adipic acid and / or glutaric acid are provided in the modified aliphatic dicarboxylic acid component of polyester and can be used for the present disclosure.

[0066] Can use ester of terephthalic acid and other modified dicarboxylic acids or their corresponding ester and / or salt to replace dicarboxylic acid.Suitable example of dicarboxylic acid ester includes but not limited to dimethyl ester, diethyl ester, dipropyl ester, diisopropyl ester, dibutyl ester and diphenyl ester.In one embodiment, ester is selected from at least one of following: methyl ester, ethyl ester, propyl ester, isopropyl ester and phenyl ester.

[0067] In one embodiment, at least a portion of the residues derived from the dicarboxylic acids and diols as described herein are derived from recycled monomer classes such as recycled dimethyl terephthalate (rDMT), recycled terephthalic acid (rTPA), recycled dimethyl isophthalate (rDMI), recycled ethylene glycol (rEG), recycled cyclohexanedimethanol (rCHDM), recycled neopentyl glycol (rNPG), and recycled diethylene glycol (rDEG). Such recycled monomer classes can be obtained by known methanolysis or glycolysis reactions that are used to depolymerize various post-consumer recycled polyesters and copolyesters. Similarly, recycled poly(ethylene terephthalate) (rPET) can be used as a feedstock (for the dicarboxylic acid and diol components) for making the polyesters of the present disclosure having recycled components. Thus, in another embodiment, the polyester composition of the present disclosure comprises at least a portion of the dicarboxylic acid residues and / or diol residues derived from (i) recycled monomer classes selected from rDMT, rTPA, rDMI, rEG, rCHDM, rDEG, rNPG, and (ii) rPET,

[0068] In some embodiments, the composition can be used as a polyester reactant or intermediate in a reaction scheme to provide a copolyester product containing recycled components. In an embodiment, the recycled components of these recycled component compositions are derived from r-propylene, and the recycled components of r-propylene are in turn derived from pyrolysis oil. In an embodiment, such recycled component compositions can be selected from r-isobutyraldehyde, r-isobutyric acid, r-isobutyric anhydride, r-dimethylketene, rTMCDn, or r-TMCD.

[0069] In one embodiment, the diol component that can be used in the copolyester composition of the present disclosure can comprise 1,4-cyclohexanedimethanol. In another embodiment, the diol component that can be used in the copolyester composition of the present disclosure comprises 1,4-cyclohexanedimethanol and 1,3-cyclohexanedimethanol. The molar ratio of cis / trans 1,4-cyclohexanedimethanol can vary in the range of 50 / 50 to 0 / 100, for example, between 40 / 60 and 20 / 80.

[0070] In one embodiment, in Component A of the copolyester blend composition, the total comonomers of the copolyester composition useful in the present disclosure from diols and acids other than ethylene glycol (EG), terephthalic acid (TPA), or dimethyl terephthalate (DMT) are 0 wt% to 15 wt%, 0.1 wt% to 15 wt%, 1 wt% to 15 wt%, 2 wt% to 15 wt%, 3 wt% to 15 wt%, 4 wt% to 15 wt%, 5 wt% to 15 wt%, or 5 wt% to 10 wt%, or 10 wt% to 15 wt%, or 2 wt% to 15 wt%, or 2 wt% to 10 wt%, or 3 wt% to 15 wt%, or 3 wt% to 10 wt%, or 4 wt% to 15 wt%, or 4 wt% to 10 wt%, or 6 wt% to 15 wt%, or 6 wt% to 10 wt%, or 7 wt% to 15 wt%, or 7 wt% to 10 wt%, or 8 wt% to 15 wt%, or 8 wt% to 10 wt%, or 9 wt% to 15 wt%, or 9 wt% to 10 wt%, or 11 wt% to 15 wt%, 12 wt% to 15 wt%, or 13 wt% to 15 wt%, 14 wt% to 15 wt%, or 12 wt% to 15 wt%.

[0071] In one embodiment, in Component A of the copolyester blend composition, the diol component of the copolyester composition useful in the present disclosure may contain 0 mole% to 15 mole% of neopentyl glycol based on the total mole% of the diol component being 100 mole%. In one embodiment, in one component of the blend, the diol component of the copolyester composition useful in the present disclosure may contain 0 mole% to 10 mole% of neopentyl glycol based on the total mole% of the diol component being 100 mole%. In one embodiment, the diol component of the copolyester composition useful in the present disclosure may contain 0 mole% to 5 mole% of neopentyl glycol based on the total mole% of the diol component being 100 mole%.

[0072] In one embodiment, in component A of the copolyester blend composition, the diol component of the copolyester composition useful in the present disclosure may contain from 5 mol% to 15 mol% of neopentyl glycol based on the total mol% of the diol component being 100 mol%. In one embodiment, the diol component of the copolyester composition useful in the present disclosure may contain from 5 mol% to 10 mol% of neopentyl glycol based on the total mol% of the diol component being 100 mol%. In one embodiment, the diol component of the copolyester composition useful in the present disclosure may contain from 1 mol% to 5 mol% of neopentyl glycol based on the total mol% of the diol component being 100 mol%. In one embodiment, the diol component of the copolyester composition useful in the present disclosure may contain from 2 mol% to 5 mol% of neopentyl glycol based on the total mol% of the diol component being 100 mol%. In one embodiment, the diol component of the copolyester composition useful in the present disclosure may contain from 3 mol% to 5 mol% of neopentyl glycol based on the total mol% of the diol component being 100 mol%.

[0073] In one embodiment, the diol component of the copolyester composition useful in the present disclosure may contain from 0 mol% to 15 mol%, from 0 mol% to 10 mol%, from 0 mol% to 5 mol%, or from 0 mol% to 4 mol%, or from 0 mol% to 3 mol%, or from 0 mol% to 2 mol%, or from 0 mol% to 1 mol%, or from 0.01 mol% to 5 mol%, or from 0.01 mol% to 4 mol%, or from 0.01 mol% to 3 mol%, or from 0.01 mol% to 2 mol%, or from 0.01 mol% to 1 mol%, or from 1 mol% to 10 mol%, 1 mol% to 5 mol%, or 2 mol% to 5 mol%, or 3 mol% to 5 mol%, or 4 mol% to 5 mol%, or 2 mol% to 4 mol%, or 3 mol% to 4 mol%, or 1 mol% to 4 mol%, 1 mol% to 3 mol%, or 1 mol% to 2 mol%, or 2 mol% to 3 mol%, or 2 mol% to 5 mol%, or 2 mol% to 4 mol%, or 2 mol% to 3 mol%, or 3 mol% to 15 mol%, or 3 mol% to 10 mol%, or 3 mol% to 9 mol%, or 3 mol% to 8 mol%, or 3 mol% to 7 mol%, or 2 mol% to 15 mol%, or 2 mol% to 10 mol%, or 2 mol% to 9 mol%, or 2 mol% to 8 mol%, or 2 mol% to 7 mol%, or 2 mol% to 5 mol%, or 1 mol% to 15 mol%, or 1 mol% to 10 mol%, or 1 mol% to 7 mol%, or 1 mol% to 5 mol%, or 1 mol% to 3 mol% of neopentyl glycol residues based on the total mol% of the diol component being 100 mol%.

[0074] In one embodiment, in component A of the copolyester blend composition, the diol component of the copolyester composition useful in the present disclosure may contain from 0 mol% to 15 mol% of 1,4-cyclohexanedimethanol based on the total mol% of the diol component being 100 mol%. In one embodiment, the diol component of the copolyester composition useful in the present disclosure may contain from 0.01 mol% to less than 15 mol% of 1,4-cyclohexanedimethanol based on the total mol% of the diol component being 100 mol%. In one embodiment, the diol component of the copolyester composition useful in the present disclosure may contain from 0 mol% to 10 mol% of 1,4-cyclohexanedimethanol based on the total mol% of the diol component being 100 mol%. In one embodiment, the diol component of the copolyester composition useful in the present disclosure may contain from 0.01 mol% to less than 10 mol% of 1,4-cyclohexanedimethanol based on the total mol% of the diol component being 100 mol%. In one embodiment, the diol component of the copolyester composition useful in the present disclosure may contain from 0.01 mol% to 5 mol% of 1,4-cyclohexanedimethanol based on the total mol% of the diol component being 100 mol%. In one embodiment, the diol component of the copolyester composition useful in the present disclosure may contain from 0.01 mol% to less than 2 mol% of 1,4-cyclohexanedimethanol based on the total mol% of the diol component being 100 mol%. In one embodiment, the diol component of the copolyester composition useful in the present disclosure may contain from 2 mol% to 100 mol% of 1,4-cyclohexanedimethanol based on the total mol% of the diol component being 10 mol%.

[0075] In one embodiment, in component A of the copolyester blend composition, the diol component of the copolyester composition useful in the present disclosure may contain from 0 mole % to 15 mole %, or from 0 mole % to 10 mole %, or from 0 mole % to 7 mole %, or from 0 mole % to 5 mole %, or from 0 mole % to 2 mole %, or from 0 mole % to 1 mole %, or from 0.01 mole % to 15 mole %, or from 0.01 mole % to 10 mole %, or from 0.01 mole % to 7 mole %, or from 0.01 mole % to 5 mole %, or from 0.01 mole % to 2 mole %, or from 1 mole % to 15 mole %, or from 1 mole % to 10 mole %, or from 1 mole % to 7 mole %, or from 1 mole % to 5 mole %, or from 1 mole % to 2 mole %, or from 3 mole % to 15 mole %, or from 3 mole % to 14 mole %, or from 3 mole % to 13 mole %, or from 3 mole % to 12 mole %, or from 3 mole % to 11 mole %, or from 3 mole % to 10 mole %, or from 3 mole % to 9 mole %, or from 3 mole % to 8 mole %, or from 3 mole % to 7 mole %, or from 2 mole % to 10 mole %, or from 2 mole % to 9 mole %, or from 2 mole % to 8 mole %, or from 2 mole % to 7 mole %, or from 2 mole % to 5 mole %, or from 1 mole % to 7 mole %, or from 1 mole % to 5 mole %, or from 1 mole % to 3 mole % of 1,4 - cyclohexanedimethanol residues, based on the total mole % of the diol component being 100 mole %.

[0076] In one embodiment, in component A of the copolyester blend composition, the diol component of the copolyester composition useful in the present disclosure may contain from 0 mole % to 15 mole %, or from 0 mole % to 10 mole %, or from 0 mole % to 7 mole %, or from 0 mole % to 5 mole %, or from 0 mole % to 3 mole %, or from 0 mole % to 2 mole %, or from 0.01 mole % to 15 mole %, or from 0.01 mole % to 10 mole %, or from 0.01 mole % to 7 mole %, or from 0.01 mole % to 5 mole %, or from 0.01 mole % to 2 mole %, or from 0.01 mole % to 1 mole %, or from 1 mole % to 15 mole %, 1 mole % to 10 mole %, or 1 mole % to 7 mole %, or 1 mole % to 5 mole %, 1 mole % to 3 mole %, or 1 mole % to 2 mole %, 3 mole % to 15 mole %, or 3 mole % to 14 mole %, or 3 mole % to 13 mole %, or 3 mole % to 12 mole %, or 3 mole % to 11 mole %, or 3 mole % to 10 mole %, or 3 mole % to 9 mole %, or 3 mole % to 8 mole %, or 3 mole % to 7 mole %, or 2 mole % to 10 mole %, or 2 mole % to 9 mole %, or 2 mole % to 8 mole %, or 2 mole % to 7 mole %, or 2 mole % to 5 mole %, or 1 mole % to 7 mole %, or 1 mole % to 5 mole %, or 1 mole % to 3 mole % of 2,2,4,4-tetramethyl-1,3-cyclobutanediol residues, based on the total mole % of the diol component being 100 mole %.

[0077] In one embodiment, in component A of the copolyester blend composition, the diol component of the copolyester composition useful in the present disclosure may contain from 0 mole % to 15 mole % of 2,2,4,4-tetramethyl-1,3-cyclobutanediol, based on the total mole % of the diol component being 100 mole %. In one embodiment, the diol component of the copolyester composition useful in the present disclosure may contain from 0.01 mole % to less than 15 mole % of 2,2,4,4-tetramethyl-1,3-cyclobutanediol, based on the total mole % of the diol component being 100 mole %. In one embodiment, the diol component of the copolyester composition useful in the present disclosure may contain from 0 mole % to 10 mole % of 2,2,4,4-tetramethyl-1,3-cyclobutanediol, based on the total mole % of the diol component being 100 mole %. In one embodiment, the diol component of the copolyester composition useful in the present disclosure may contain from 0.01 mole % to less than 10 mole % of 2,2,4,4-tetramethyl-1,3-cyclobutanediol, based on the total mole % of the diol component being 100 mole %. In one embodiment, the diol component of the copolyester composition useful in the present disclosure may contain from 0.01 mole % to 5 mole % of 2,2,4,4-tetramethyl-1,3-cyclobutanediol, based on the total mole % of the diol component being 100 mole %. In one embodiment, the diol component of the copolyester composition useful in the present disclosure may contain from 0 mole % to less than 5 mole % of 2,2,4,4-tetramethyl-1,3-cyclobutanediol, based on the total mole % of the diol component being 100 mole %.

[0078] In all embodiments, it is understood that some other diol residues may be formed in situ during processing. The total amount of diethylene glycol residues may be present in the copolyester useful in the present disclosure in any amount, whether formed in situ during processing or added intentionally, or both.

[0079] For example, in some embodiments, in component A of the copolyester blend composition, the total amount of diethylene glycol residues (whether formed in situ during processing or added intentionally, or both) may be from 1 mole % to 15 mole %, or from 1 mole % to 10 mole %, or from 2 mole % to 10 mole %, or from 2 mole % to 9 mole %, or from 3 mole % to 9 mole %, or from 3 mole % to 10 mole %, or from 3 mole % to 9 mole %, or from 3 mole % to 8 mole %, or from 4 mole % to 10 mole %, or from 4 mole % to 9 mole %, or from 4 mole % to 8 mole %, or from 4 mole % to 7 mole %, or from 5 mole % to 10 mole %, or from 5 mole % to 9 mole %, or from 5 mole % to 8 mole %, or from 5 mole % to 7 mole % of diethylene glycol residues, based on the total mole % of the diol component being 100 mole %.

[0080] In one embodiment, in Component A of the copolyester blend composition, the total amount of diethylene glycol residues present in the copolyester useful in the present disclosure (whether formed in situ during processing, intentionally added, or both) may be 5 mol% or less, or 4 mol% or less, or 3.5 mol% or less, or 3.0 mol% or less, or 2.5 mol% or less, or 2.0 mol% or less, or 1.5 mol% or less, or 1.0 mol% or less, or from 1 mol% to 4 mol%, or from 1 mol% to 3 mol%, or from 1 mol% to 2 mol% of diethylene glycol residues, based on the total mol% of the diol component being 100 mol%, or from 2 mol% to 8 mol%, or from 2 mol% to 7 mol%, or from 2 mol% to 6 mol%, or from 2 mol% to 5 mol%, or from 3 mol% to 8 mol%, or from 3 mol% to 7 mol%, or from 3 mol% to 6 mol%, or from 3 mol% to 5 mol%. Or, in some embodiments, there are no intentionally added diethylene glycol residues.

[0081] In one embodiment, in Component B of the copolyester blend composition, the total amount of diethylene glycol residues present in the copolyester useful in the present disclosure (whether formed in situ during processing, intentionally added, or both) may be 50 mol% or less, or 40 mol% or less, or 35 mol% or less, or 30 mol% or less, or 25 mol% or less, or 20 mol% or less, or from 20 mol% to 50 mol%, or from 20 mol% to 40 mol%, or from 20 mol% to 30 mol% of diethylene glycol residues, based on the total mol% of the diol component being 100 mol%.

[0082] For all embodiments, the remainder of the diol component may contain any amount of ethylene glycol residues, based on the total mol% of the diol component being 100 mol%. In one embodiment, the copolyester useful in the present disclosure may contain 50 mol% or more, or 55 mol% or more, or 60 mol% or more, or 65 mol% or more, or 70 mol% or more, or 75 mol% or more, or 80 mol% or more, or 85 mol% or more, or 90 mol% or more, or 95 mol% or more, or 98 mol% or more, or from 50 mol% to 90 mol%, or from 55 mol% to 90 mol%, or from 50 mol% to 80 mol%, or from 55 mol% to 80 mol%, or from 60 mol% to 80 mol%, or from 50 mol% to 75 mol%, or from 55 mol% to 75 mol%, or from 60 mol% to 75 mol%, or from 65 mol% to 75 mol% of ethylene glycol residues, based on the total mol% of the diol component being 100 mol%.

[0083] For all embodiments, the diol component of the copolyester composition useful in the present disclosure may contain up to 10 mol%, or up to 9 mol%, or up to 8 mol%, or up to 7 mol%, or up to 6 mol%, or up to 5 mol%, or up to 4 mol%, or up to 3 mol%, or up to 2 mol%, or up to 1 mol% or less of one or more other modified diols (other modified diols are defined as diols that are not ethylene glycol, diethylene glycol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, neopentyl glycol, or 1,4-cyclohexanedimethanol). In certain embodiments, the copolyester useful in the present disclosure may contain 10 mol% or less of one or more other modified diols; 5 mol% or less of one or more other modified diols; 2 mol% or less of one or more other modified diols; 1 mol% or less of one or more other modified diols. In certain embodiments, the copolyester useful in the present disclosure may contain 5 mol% or less of one or more other modified diols. In certain embodiments, the copolyester useful in the present disclosure may contain 3 mol% or less of one or more other modified diols. In another embodiment, the copolyester useful in the present disclosure may contain 0 mol% of other modified diols. However, it is expected that some other diol residues may form in situ, and thus the amount of residues formed in situ is also an embodiment of the present disclosure.

[0084] In an embodiment, if used, the other modified diols for the copolyester as defined herein contain up to 20 carbon atoms, or in some embodiments 2 to 16 carbon atoms. Examples of other modified diols include, but are not limited to, 1,2-propanediol, 1,3-propanediol, isosorbide, 1,4-butanediol, 1,5-pentanediol, 2-methyl-1,3-propanediol (MPDiol), 1,6-hexanediol, p-xylene glycol, polytetramethylene glycol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD), and mixtures thereof. In one embodiment, isosorbide is another modified diol. In another embodiment, the other modified diols include, but are not limited to, at least one of 1,3-propanediol and 1,4-butanediol. In one embodiment, 1,3-propanediol and / or 1,4-butanediol may be excluded. If 1,4-butanediol or 1,3-butanediol is used, then in one embodiment, greater than 4 mol% or greater than 5 mol% may be provided. In one embodiment, at least one other modified diol is 1,4-butanediol, which is present in an amount of 1 mol% to 10 mol%.

[0085] In some embodiments, based on the total mole percent of diol or diacid residues, respectively, the copolyester compositions according to the present disclosure may optionally contain from 0 mole % to 10 mole %, such as from 0 mole % to 5 mole %, from 0 mole % to 1 mole %, from 0.01 mole % to 5 mole %, from 0.01 mole % to 1 mole %, from 0.05 mole % to 5 mole %, from 0.05 mole % to 1 mole %, or from 0.1 mole % to 0.7 mole % of residues of one or more branching monomers (also referred to herein as branching agents), the branching monomers having 3 or more carboxyl substituents, hydroxyl substituents, or combinations thereof. In certain embodiments, the branching monomer or branching agent may be added before and / or during and / or after the copolyester polymerization. In some embodiments, the copolyesters useful in the present disclosure may thus be linear or branched.

[0086] Examples of branching monomers include, but are not limited to, polyfunctional acids or polyfunctional alcohols such as trimellitic acid, trimellitic anhydride, pyromellitic dianhydride, trimethylolpropane, glycerol, pentaerythritol, citric acid, tartaric acid, 3-hydroxyglutaric acid, etc. In one embodiment, the branching monomer residues may comprise from 0.1 mole % to 0.7 mole % of residues of one or more of at least one selected from the group consisting of trimellitic anhydride, pyromellitic dianhydride, glycerol, sorbitol, 1,2,6-hexanetriol, pentaerythritol, trimethylolethane, and / or trimellitic acid. The branching monomer may be added to the copolyester reaction mixture or blended with the copolyester in the form of a concentrate, such as described in U.S. Patent Nos. 5,654,347 and 5,696,176, the disclosures of which regarding the branching monomer are incorporated herein by reference.

[0087] The copolyesters useful in the present disclosure may contain at least one chain extender. Suitable chain extenders include, but are not limited to, polyfunctional (including but not limited to bifunctional) isocyanates, polyfunctional epoxides (including, for example, epoxidized novolac resins), and phenoxy resins. In certain embodiments, the chain extender may be added at the end of the polymerization process or after the polymerization process. If added after the polymerization process, the chain extender may be incorporated during a conversion process such as injection molding or extrusion by compounding or by addition.

[0088] The amount of chain extender used may vary depending on the specific monomer composition used and the desired physical properties, but is typically from about 0.1 weight percent to about 10 weight percent, such as from about 0.1 to about 5 weight percent, based on the total weight of the copolyester.

[0089] Unless otherwise specified, the copolyester compositions expected to be used in the present disclosure may have at least one of the intrinsic viscosity ranges described herein and at least one of the monomer ranges of the copolyester compositions described herein. Unless otherwise specified, it is also expected that the copolyester compositions useful in the present disclosure may have at least one of the Tg ranges described herein and at least one of the monomer ranges of the copolyester compositions described herein. Unless otherwise specified, it is further expected that the copolyester compositions useful in the present disclosure may have at least one of the intrinsic viscosity ranges described herein, at least one of the Tg ranges described herein, and at least one of the monomer ranges of the copolyester compositions described herein.

[0090] For embodiments of the present disclosure, the copolyester compositions useful in the present disclosure may exhibit at least one of the following intrinsic viscosities, as measured at 25 °C at a concentration of 0.25 g / 50 ml in 60 / 40 (weight / weight) phenol / tetrachloroethane: 0.50 to 1.0 dL / g; 0.60 to 1.0 dL / g; 0.60 to 0.90 dL / g; 0.60 to 0.80 dL / g; 0.6 to 0.75 dL / g; 0.6 to 0.70 dL / g; 0.65 to 0.80 dL / g; 0.70 to 0.80 dL / g; 0.50 to 0.75 dL / g; 0.55 to 0.75 dL / g; 0.58 to 0.75 dL / g; 0.60 to 0.75 dL / g; 0.60 to 0.70 dL / g; 0.58 to 0.70 dL / g; or 0.55 to 0.70 dL / g.

[0091] The glass transition temperature (Tg) of the copolyester composition is measured using a TA DSC 2920 from ThermalAnalyst Instrument at a scan rate of 20 °C / min. The value of the glass transition temperature is measured during the second heating.

[0092] In certain embodiments, the copolyester compositions of the present disclosure comprise a copolyester having a Tg of 50 °C or higher, or 60 °C or higher, or 50 °C or higher; or 50 °C to 90 °C or 500 °C to 80 °C; or 60 °C to 70 °C; or 60 °C to 80 °C; or 70 °C to 80 °C. In certain embodiments, these Tg ranges can be met with or without the addition of at least one plasticizer during polymerization.

[0093] In one embodiment, the copolyester can be produced by a process in a homogeneous solution, by a transesterification process in the melt, and by a two-phase interfacial process. Suitable methods include, but are not limited to, the step of reacting one or more dicarboxylic acids with one or more diols at a temperature of 100 °C to 315 °C and a pressure of 0.1 to 760 mmHg for a time sufficient to form the copolyester. For methods of producing copolyesters, see U.S. Patent No. 3,772,405, the disclosure of which is hereby incorporated herein by reference.

[0094] Generally, the copolyester can be prepared by condensing a dicarboxylic acid or a dicarboxylic acid ester with a diol in the presence of a catalyst at an elevated temperature that gradually increases during the condensation process (up to a temperature of about 225 °C to 310 °C) in an inert atmosphere and carrying out the condensation at a low pressure during the later stage of the condensation, as further described in detail in U.S. Patent No. 2,720,507, which is incorporated herein by reference.

[0095] In some embodiments, during the process of preparing the copolyester composition useful in the present disclosure, certain agents that color the polymer can be added to the melt, including toners or dyes. In one embodiment, a bluing toner is added to the melt to reduce the b* of the resulting copolyester polymer melt-phase product. Such bluing agents include blue inorganic and organic toners and / or dyes. Additionally, red toners and / or dyes can be used to adjust the a* color. Organic toners can be used, for example, blue and red organic toners such as those described in U.S. Patent Nos. 5,372,864 and 5,384,377, which are incorporated herein by reference in their entirety. The organic toners can be fed as a premixed composition. The premixed composition can be a neat blend of red and blue compounds, or the composition can be pre-dissolved or slurried in one of the copolyester raw materials (e.g., ethylene glycol).

[0096] The total amount of the added toner components can depend on the amount of inherent yellow in the base copolyester and the efficacy of the toner. In one embodiment, a concentration of up to about 15 ppm of the combined organic toner components and a minimum concentration of about 0.5 ppm can be used. In one embodiment, the total amount of the bluing additive can be in the range of 0.5 to 10 ppm. In one embodiment, the toner can be added to the esterification zone or the polycondensation zone. Preferably, the toner is added to the esterification zone or added to the early stage of the polycondensation zone, such as added to a prepolymerization reactor. In some embodiments, the toner can be added as a masterbatch after polymerization.

[0097] In some embodiments, the copolyester composition may further contain from 0.01% to 25% by weight of the overall composition of common additives such as colorants, toners, dyes, mold release agents, flame retardants, plasticizers, glass bubbles, glass fibers, natural fibers, nucleating agents, friction modifiers, stabilizers (including but not limited to UV stabilizers, heat stabilizers, and / or their reaction products), fillers, and impact modifiers. Examples of commercially available impact modifiers include but are not limited to ethylene / propylene terpolymers; functionalized polyolefins such as those containing methyl acrylate and / or glycidyl methacrylate; styrene-based block copolymer impact modifiers; and various acrylic core / shell type impact modifiers. Residues of such additives are also contemplated as part of the copolyester composition.

[0098] Reinforcing materials can be added to the compositions useful in the present disclosure. The reinforcing materials can include but are not limited to carbon filaments, silicates, mica, clay, talc, titanium dioxide, wollastonite, glass flakes, beads and fibers, natural fibers and polymer fibers, and combinations thereof. In one embodiment, the reinforcing materials include glass such as fiberglass filaments, mixtures of glass and talc, mixtures of glass and mica, and mixtures of glass and polymer fibers.

[0099] The copolyester blends of the present disclosure can be prepared by any conventional processing techniques known in the art such as melt blending, melt mixing, compounding via single screw extrusion, compounding via twin screw extrusion, or any continuous extruder such as a Kokneader extruder, a planetary gear extruder, a Henschel extruder, or any batch melt mixing equipment such as a Banbury mixer, or combinations of the foregoing. In one embodiment, the copolyester blend is compounded at a temperature of 220°C - 320°C. In one embodiment, the copolyester blend is compounded at a temperature of 220°C - 300°C. In one embodiment, the copolyester blend can be pre-dried at 60°C - 160°C. In one embodiment, the copolyester blend is not pre-dried. In one embodiment, the compounding can be carried out under vacuum. In one embodiment, the compounding is not carried out under vacuum.

[0100] In one aspect of the present disclosure, the copolyester composition further contains recycled polyethylene terephthalate (rPET) or recycled polyester. It is desirable to reincorporate recycled PET (rPET) or recycled polyester into new molded or extruded articles. The use of rPET or recycled polyester reduces the product environmental footprint and improves the overall life cycle analysis. The use of rPET or recycled polyester has economic advantages and will reduce the total amount of packaging-related products sent to landfills or that may ultimately pollute the ocean or other water bodies.

[0101] There is no restriction on the recycled polyethylene terephthalate (rPET) or recycled polyester that can be used to prepare blends with the copolyester compositions of the present disclosure. In one embodiment, the rPET or recycled polyester is recycled mechanically. In one embodiment, the rPET or recycled polyester is produced from monomers recycled chemically (produced by any known depolymerization method).

[0102] In one embodiment, the rPET may have minor modifications, such as up to 5 mol% isophthalic acid and / or up to 5 mol% CHDM or other diols. In one embodiment, the recycled PET (rPET) can be almost any "waste" industrial or post-consumer PET. In one embodiment, the rPET that can be used in the blend compositions of the present disclosure can be post-consumer recycled PET. In one embodiment, the rPET is post-industrial recycled PET. In one embodiment, the rPET is post-consumer PET from soft drink bottles. In one embodiment, shredded PET fibers, shredded PET films, and inferior PET polymers are also suitable rPET sources. In one embodiment, the recycled PET mainly contains PET, but other copolyesters can also be used, especially when they have a structure similar to PET, such as PET copolymers, etc. In one embodiment, the rPET is clean. In one embodiment, the rPET is substantially free of contaminants. In one embodiment, the rPET can be in the form of flakes.

[0103] In one embodiment, the copolyester composition contains 0 wt% to 50 wt% of rPET. In one embodiment, the copolyester composition contains 1 wt% to 40 wt% of rPET. In one embodiment, the copolyester composition contains 2 wt% to 30 wt% of rPET. In one embodiment, the copolyester composition contains 3 wt% to 20 wt% of rPET. In one embodiment, the copolyester composition contains 4 wt% to 15 wt% of rPET. In one embodiment, the copolyester composition contains 5 wt% to 10 wt% of rPET.

[0104] In one embodiment, up to about 50 wt% of rPET can be incorporated into the copolyester compositions of the present disclosure. In one embodiment, the rPET / copolyester blend is 15 wt% - 50 wt% of rPET. In one embodiment, the rPET / copolyester blend is 25 wt% - 40 wt% of rPET. In one embodiment, the rPET / copolyester blend is 20 wt% - 30 wt% of rPET. In one embodiment, the rPET / copolyester blend is 15 wt% - 50 wt% of rPET and 50 wt% - 85 wt% of at least one copolyester.

[0105] The copolyester / rPET blend can be prepared by conventional processing techniques known in the art, such as melt blending, melt mixing, compounding via single-screw extrusion, compounding via twin-screw extrusion, batch melt mixing equipment, or a combination of the above. In one embodiment, the copolyester / rPET blend is compounded at a temperature of 220°C - 320°C. In one embodiment, the copolyester / rPET blend is compounded at a temperature of 220°C - 300°C. In one embodiment, the copolyester / rPET blend can be pre-dried at 60°C - 160°C. In one embodiment, the copolyester / rPET blend is not pre-dried. In one embodiment, the compounding can be carried out under vacuum. In one embodiment, the compounding is not carried out under vacuum.

[0106] The following examples further illustrate how the copolyesters of the present disclosure can be prepared and evaluated, and they are intended to be merely exemplary and not intended to limit their scope. Unless otherwise indicated, parts are by weight, temperature is in degrees Celsius (centigrade) or at room temperature, and pressure is equal to or close to atmospheric pressure.

[0107] Examples

[0108] The present disclosure can be further illustrated by the following examples of its preferred embodiments, but it should be understood that these examples are included for illustrative purposes only and are not intended to limit the scope of the present disclosure unless specifically stated otherwise.

[0109] The copolyester composition of the present disclosure is a blend of copolyesters that meets the definition of RIC-1 and has sufficient properties to be used as an adhesive layer.

[0110] Resin Identification Code (RIC-1) Definition - 1 is for PET materials that meet the following criteria:

[0111] 1. The polymer must be made from at least 90 wt% of the monomers that would make pure PET. These monomers include TPA, DMT, and EG; and

[0112] 2. The polymer must have a crystalline melting point (T m ) between 225°C and 255°C. T m is measured in the second heat cycle of DSC measurements carried out at 10°C / min.

[0113] As shown in Table 1, one embodiment of the present disclosure is a physical blend composition of Component A - 100 mol% terephthalic acid, 37 mol% DEG, 63 mol% EG and Component B - 100 mol% terephthalic acid, 3.5 mol% CHDM, 96.5 mol% EG (a blend of Example #1 and Example #2). Example #8 is a 50:50 blend of Example #1 and Example #2. Example #8 meets two elements of the criteria defined by RIC-1. The weight percentage of PET in this formulation is slightly higher than 90%, and the crystal melting point is approximately 230 °C (which is within the defined range of 225 °C to 255 °C).

[0114] Without being bound by any theory, the blends suitable for the present disclosure are physical blends of copolyester resins. Reactor-grade compositions that meet the compositional range requirements do not meet the criteria defined by RIC-1. However, physical blends of copolyester compositions can achieve the adhesion characteristics and RIC1 characteristics required in the present disclosure.

[0115] The chemical composition of Example #8 is Component A - 100 mol% terephthalic acid, 37 mol% DEG, 63 mol% EG and Component B - 100 mol% terephthalic acid, 3.5 mol% CHDM, 96.5 mol% EG. The 50:50 blend has a T m . The same composition was targeted and produced in a laboratory reactor (see Examples #14, #15 and #16), and this resulted in a T m of approximately 214 °C. m This T

[0116] is too low to meet the RIC-1 criteria. m Enabling resin blending allows the composition to take full advantage of the respective characteristics of the two resins. Compared with other amorphous binder resins, the blend provides good adhesion characteristics. This is illustrated in Table 2. Table 2 shows the self-sealing temperature and the temperature required to bond to Example #1. By blending the two resins instead of making a completely homogeneous reactor-grade material, the adhesion characteristics of the Example 1 resin are maintained at a higher level. This effect is more obvious when observing the second cycle T m in the DSC data in Table 3. The pure Example #2 resin has a second cycle T m of 240 °C. Although the pure Example #1 resin does not have a second cycle T m ; however, when these two resins are blended together, the blend has a second cycle T mIs only 214 °C. Blending the two materials allows the crystallization behavior of the resin to be fully retained to meet the RIC-1 requirements. However, reactor-grade resins with a similar composition will not meet the RIC-1 requirements. Therefore, a physical blend is needed in the present disclosure to obtain the desired properties.

[0117] Example #1 is PET modified with 37 mol% DEG. The DEG level has an impact on reducing the T of the blend composition g and improving the adhesion properties. For example, Examples #3 and #4 illustrate that adhesive layers with 20 mol% and 23 mol% DEG are suitable for use as adhesive formulations in some embodiments of the present disclosure. The DEG level ranges from about 20 mol% to about 50 mol%. Example #5 is PET modified with 3.5 mol% CHDM. In some embodiments, the range of CHDM is 0 mol% to about 5 mol%. In other embodiments, the range of CHDM is up to about 10 mol%. If the level of CHDM is too high, it will significantly affect the level of the Example #1 composition that can be added to the blend and still remain within the defined requirements of RIC-1. In some embodiments, other diols and diacids can be used to modify Example #1 or Example #2. However, in some embodiments, the range of other modifying diols or diacids may need to be kept up to 10 mol% to maintain the RIC-1 requirements.

[0118] Table 1: Examples

[0119]

[0120]

[0121]

[0122]

[0123] - The PET% calculation is based on the ratio of the starting monomers used to produce the formulation. The total weight of TPA and EG in the formulation is divided by the total monomer weight of the formulation. The resin compositions of Examples #1 - #5 are manufactured by and available from Eastman Chemical Company.

[0124] For the heat seal data in Table 2, seal tests were performed on one-inch-wide samples on a Kopp Labormaster HCT 3000 heat seal hot tack tester. Two one-inch strips of material were sealed together at a pressure of approximately 276 N (Newtons) for a duration of 0.1 second. For some tests, the copolyesters were self-sealed (a sample of Example #1 copolyester was sealed to another sample of Example #1 copolyester), and in other tests, each copolyester sample was sealed to Example 2. The samples were allowed to cool at room temperature for 60 seconds and then the peel force was tested.

[0125] Table 2: Heat Seal Data

[0126]

[0127]

[0128] Table 3: DSC Data

[0129]

[0130] The present invention is illustrated in more detail by the specific embodiments given below. It is to be understood that these embodiments are illustrative implementations and are not intended to be limiting of the present invention, but rather should be broadly interpreted within the scope and content of the appended claims.

Claims

1. An adhesive composition comprising a copolyester blend, said copolyester blend comprising A) 25% to 75% by weight of at least one copolyester composition, said copolyester composition comprising: (a) A dicarboxylic acid component, said dicarboxylic acid component comprising: (i) 85 mol% to 100 mol% of terephthalic acid residues, and (ii) 0 mol% to 15 mol% of aromatic and / or aliphatic dicarboxylic acid residues having up to 20 carbon atoms; and (b) A diol component, said diol component comprising: (i) 0 mol% to 15 mol% of residues of 2,2,4,4-tetramethyl-1,3-cyclobutanediol (TMCD); residues of 1,4-cyclohexanedimethanol (CHDM); residues of NPG; and residues of DEG, one or more of which, whether formed in situ or not; and wherein the remainder of said diol component comprises: (ii) Residues of ethylene glycol, and (iii) Optionally, 0 mol% to 10 mol% of residues of at least one other modified diol; wherein the total mol% of said dicarboxylic acid component is 100 mol%, and wherein the total mol% of said diol component is 100 mol%; and B) 75% to 25% by weight of at least one copolyester composition, said copolyester composition comprising (a) A dicarboxylic acid component, said dicarboxylic acid component comprising: (i) 85 mol% to 100 mol% of terephthalic acid residues, and (ii) 0 mol% to 15 mol% of aromatic and / or aliphatic dicarboxylic acid residues having up to 20 carbon atoms; and (b) A diol component, said diol component comprising: (i) 20 mol% to 50 mol% of DEG residues; and (ii) 50 mol% - 80 mol% of ethylene glycol (EG) residues, and (iii) Optionally, 0 mol% to 10 mol% of residues of at least one other modified diol; wherein the total mol% of said dicarboxylic acid component is 100 mol%, and wherein the total mol% of said diol component is 100 mol%; and wherein the copolyester blend has a melting temperature (T m ) of 190 °C to 255 °C; and wherein the Tg of said copolyester blend is 50°C - 80°C; and wherein the intrinsic viscosity of said copolyester blend is 0.60 to 1.0 dL / g; and wherein the adhesive composition provides a peel force of 2 - 12 N.

2. The adhesive composition according to claim 1, further comprising at least one polyester having recycled components.

3. The adhesive composition according to claim 1, wherein the copolyester blend further comprises rPET.

4. The adhesive composition according to claim 1, wherein the EG is recycled EG (rEG).

5. The adhesive composition according to claim 1, wherein the CHDM is rCHDM, or the CHDM is produced from rDMT.

6. The adhesive composition according to claim 1, wherein the TMCD is rTMCD.

7. The adhesive composition according to claim 1, wherein the DEG is recycled DEG, or the DEG is produced from rEG.

8. The adhesive composition according to claim 1, wherein the copolyester blend has a total comonomer content of 0 wt% - 10 wt% of diols and acids other than ethylene glycol (EG), terephthalic acid (TPA) or dimethyl terephthalate (DMT) or any combination thereof, and the total comonomer content must be less than 10 wt%.

9. The adhesive composition article according to claim 1, wherein the copolyester blend has a melting temperature (T m ) of 225°C - 255°C.

10. The adhesive composition according to claim 1, wherein the Tg of the copolyester blend is 50 °C to 80 °C.

11. The adhesive composition according to claim 1, wherein the Tg of the copolyester blend is 60 °C to 75 °C.

12. The adhesive composition according to claim 1, wherein the intrinsic viscosity of the copolyester blend is 0.60 to 0.9 dL / g.

13. The adhesive composition according to claim 1, wherein the adhesive has a peel strength of 2 - 12 N.

14. A substrate having a coating comprising the composition according to claim 1.

15. A paper or polyester substrate having a coating comprising the composition according to claim 1.

16. A bakeable food container, the components of which are bonded with the composition according to claim 1.

17. A thermoformed container or article, the components of which are bonded with the composition according to claim 1.

18. A capping film adhered to an article with the adhesive composition according to claim 1.

19. A recyclable substrate comprising a polyester container or bottom tray, a peelable film joined to the container or tray to form a receiving space therebetween, and an adhesive layer adhering the film to the container or tray, wherein the adhesive layer comprises a copolyester blend, and the copolyester blend comprises A) 45 wt% - 65 wt% of at least one copolyester composition, the copolyester composition comprising: (a) A dicarboxylic acid component, the dicarboxylic acid component comprising: (i) 85 mol% to 100 mol% of terephthalic acid residues, and (ii) 0 mol% to 15 mol% of aromatic and / or aliphatic dicarboxylic acid residues having up to 20 carbon atoms; and (b) A diol component, the diol component comprising: (i) 1 mol% to 10 mol% of 2,2,4,4 - tetramethyl - 1,3 - cyclobutanediol (TMCD) residues; 1,4 - cyclohexanedimethanol (CHDM) residues; NPG residues and DEG residues, one or more of which, whether formed in situ or not, and (ii) 90 mol% - 99 mol% of ethylene glycol (EG) residues; and wherein the total mole% of the dicarboxylic acid component is 100 mol%, and wherein the total mole% of the diol component is 100 mol%; and B) 35 wt% - 55 wt% of at least one copolyester composition, the copolyester composition comprising (a) A dicarboxylic acid component, the dicarboxylic acid component comprising: (i) 85 mol% to 100 mol% of terephthalic acid residues, and (ii) 0 mol% to 15 mol% of aromatic and / or aliphatic dicarboxylic acid residues having up to 20 carbon atoms; and (b) A diol component, the diol component comprising: (i) 20 mol% to 50 mol% of DEG residues; and (ii) 50 mol% - 80 mol% of ethylene glycol (EG) residues, and wherein the total mol% of the dicarboxylic acid component is 100 mol%, and wherein the total mol% of the diol component is 100 mol%; and wherein the copolyester blend has a melting temperature (T m ) of 225°C - 255°C; and wherein the Tg of the copolyester blend is 60 °C - 75 °C; and wherein the inherent viscosity of the copolyester blend is 0.60 to 0.90 dL / g; and wherein the adhesive composition provides a peel force of 2 - 12 N.

20. The substrate according to claim 15 or claim 19, wherein the substrate is capable of being recycled in a PET recycling stream.

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