polymer composition

Abstract

This disclosure provides polymer compositions based on polyvinyl alcohol. One aspect provides a polymer composition comprising about 60% to about 99% by weight of polymer (A), about 0.05% to about 10% by weight of phosphite, at least one additive selected from vitamin E and epoxidized soybean oil, and about 0% to about 10% by weight of PEG-grafted polyvinyl acetate copolymer. Methods for preparing said polymer composition, its use, and articles prepared therefrom are also provided.

Description

Technical Field

[0001] This disclosure relates primarily to polymer compositions, and more specifically, to polymer compositions comprising polymers and additives, suitable for, but not limited to, 3D printing, packaging, films, coatings, and water-soluble tooling. This disclosure also provides methods for preparing and using the compositions of the invention. Background Technology

[0002] Synthetic polymers (i.e., plastics) are widely used in various aspects of industrial and consumer products due to their ease of processing, durability, and the wide range of physical properties achievable through different polymer chemical compositions. Thermoplastics are polymers that become soft and moldable when heated above a certain temperature and harden upon cooling. These properties make them particularly useful for processes such as injection molding, compression molding, calendering, and extrusion. For similar reasons, thermoplastics are also widely used in 3D printing.

[0003] 3D printing refers to the process of building three-dimensional objects from digital models; it is sometimes called "additive manufacturing." The term encompasses many processes in which material is deposited, joined, or hardened under computer control to create three-dimensional objects. Materials are typically added together layer by layer. 3D printing is commonly used for prototyping, particularly in industry, but is increasingly being used for non-industry applications as well. Furthermore, some 3D printing processes have evolved to the point where they can be used for large-scale industrial production. 3D printing is particularly advantageous for producing complex 3D shapes or geometries that may be difficult to produce using other methods such as machining (sometimes referred to in this field as "subtractive manufacturing," where material removal is a common process).

[0004] While 3D printing methods have been applied to a wide variety of materials, polymers are the primary material used in 3D printing processes due to their ease of fabrication and handling. One of the most common 3D printing processes is fused deposition modeling (also known as filament fabrication), which uses a continuous thermoplastic filament. Similarly, in fused particle fabrication, granular polymer is fed through a nozzle in a molten state. For these types of 3D printing processes, a thermoplastic polymer composition is required that is compatible with the formulation process (e.g., the fabrication of granules, pellets, and filaments) and all stages of the 3D printing process, while also possessing physical and chemical properties suitable for the intended use of the final printed object.

[0005] While thermoplastics are particularly useful in manufacturing, the remarkable durability of synthetic polymers means they can persist in the natural environment for hundreds of years. In particular, plastic fragments shorter than about 5 millimeters (often referred to as “microplastics”) have become a growing environmental problem as these particles enter natural ecosystems from various man-made sources such as cosmetics, clothing, and industrial processes. They accumulate in natural ecosystems and cause harm, such as to aquatic life in the ocean.

[0006] Therefore, there is a growing need for more environmentally friendly polymers in the manufacture of consumer goods, polymers that are easily recyclable or biodegradable at the end of the product's lifespan. Similarly, there is a need for more environmentally friendly packaging materials, such as polymer films. Polyvinyl alcohol (PVA) is particularly attractive in this regard because it is water-soluble and breaks down into carbon dioxide and water in solution by microorganisms commonly found in municipal wastewater systems. PVA is also thermoplastic, allowing for injection molding and extrusion. Furthermore, PVA's water solubility makes it particularly attractive for certain 3D printing processes that use soluble scaffolds. In these processes, sacrificial support structures are created as part of the printing process to enable the printing of complex geometries, such as objects with angles greater than 45 degrees or overhangs. At the end of the printing process, the support structure can be removed, for example, by immersing the printed object in water until the support structure dissolves from the final product's structure.

[0007] However, manufacturing with polyvinyl alcohol remains complex. In particular, the thermoplastic processing of pure polyvinyl alcohol is hampered by undesirable properties such as poor flowability and thermal degradation / decomposition. Therefore, there is a need for polyvinyl alcohol formulations possessing one or more of the following properties: good melt and flow properties, resistance to thermal degradation / decomposition and / or discoloration during multiple processing steps in the formulation and 3D printing processes, good cold water solubility, and compatibility with common 3D printing processes such as fused deposition modeling, including filament fabrication and fused particle fabrication. The polymer compositions disclosed herein are designed to meet these requirements. Summary of the Invention

[0008] In a first aspect, this disclosure provides a polymer composition comprising, in each case, based on the total weight of the polymer composition:

[0009] (a) about 60% by weight to about 99% by weight of polymer (A), wherein polymer (A) in each case comprises, based on the total number of moles of polymer (A):

[0010] (i) Structural units of formula (I) of approximately 66 mol% to approximately 79 mol%:

[0011] and

[0012] (ii) Structural units of formula (II) of about 10 mol% to about 34 mol%:

[0013]

[0014] Among them, each R 1 Each R is independently hydrogen or alkyl. 2 Independently alkyl; and

[0015] The polymer (A) has a weight-average molecular weight (Mw) of about 26,000 to about 87,000 and a number-average molecular weight (Mn) of about 4,000 to about 45,000.

[0016] (b) About 0.05% by weight to about 10% by weight of phosphites selected from the group consisting of formulas (V) and (VI):

[0017]

[0018] Where R a R b R c and R d Each is an independent hydrocarbon group;

[0019] (c) at least one additive, selected from:

[0020] (i) Vitamin E; and

[0021] (ii) epoxidized soybean oil; and

[0022] (d) about 0 to about 10% by weight of PEG-grafted polyvinyl acetate copolymer, wherein the degree of hydrolysis of the polyvinyl acetate copolymer is about 30 mol% to about 98 mol%, the weight-average molecular weight (Mw) is about 5,000 to about 40,000, and the number-average molecular weight (Mn) is about 1,000 to about 20,000.

[0023] In another aspect, this disclosure provides a polymer composition comprising, in each case, based on the total weight of the polymer composition:

[0024] (a) about 60% to about 99% by weight of polymer (A), wherein polymer (A) is polyvinyl alcohol with a degree of hydrolysis of about 66% to about 79%, wherein the weight-average molecular weight (Mw) of polymer (A) is about 26,000 to about 87,000, and the number-average molecular weight (Mn) is about 4,000 to about 45,000; and

[0025] Components (b), (c), and (d) as defined in the first aspect above.

[0026] In another aspect, this disclosure provides the use of the compositions described herein in 3D printing. It also provides the use of the compositions described herein in fused deposition modeling, and in the manufacture of molten particles. Furthermore, it provides the use of the compositions described herein as a water-soluble carrier in 3D printing. Finally, it provides the use of the compositions described herein in packaging, films, coatings, or water-soluble tools.

[0027] In one aspect, this disclosure further provides a water-soluble carrier for 3D printing comprising the composition described herein.

[0028] In one aspect, a method for preparing the composition described herein is also provided, the method comprising forming a premix of components (a) to (d) as defined herein, and extruding the premix through a die.

[0029] On the other hand, a method for preparing filaments is provided, the method comprising extruding granules prepared by the method described herein from a single-screw extruder.

[0030] On the other hand, 3D printed articles prepared from the compositions described herein are also provided.

[0031] Other aspects and embodiments of the invention are set forth in the appended independent and dependent claims. It should be understood that features of the dependent claims can be combined with each other and can be combined with features of the independent claims in combinations other than those expressly specified in the claims. Furthermore, the methods described herein are not limited to specific embodiments (such as those listed below), but include and are contemplated any combination of features presented herein. The above and other objects, features, and advantages of this disclosure will be more fully revealed hereinafter in light of the detailed description that follows. Detailed Implementation

[0032] While various exemplary embodiments are described or suggested herein, other exemplary embodiments utilizing methods and materials similar to or equivalent to those described or suggested herein are covered within the overall inventive concept. Aspects and features of apparatuses and methods not described in detail herein can be implemented using any conventional techniques for achieving such aspects and features.

[0033] As used in this specification and claims, the singular forms “a,” “an,” and “the” include cases where the referred to is plural, unless the context clearly specifies otherwise.

[0034] In this specification, unless otherwise stated, the term "about" for the amount of a modified component refers to numerical variations that may occur, for example, due to typical measurement and processing procedures used in the preparation of concentrates, mixtures, or solutions in the real world, due to unforeseen errors in these procedures, due to differences in the manufacture, origin, or purity of the materials used or the materials used in the process, and for reasons such as these. The term "about" also includes different amounts of the composition resulting from a particular initial mixture due to different equilibrium conditions. Whether or not modified by the term "about," the claims include amounts equivalent to the stated quantity.

[0035] The ranges provided herein specify exemplary amounts for each component. Each of these ranges may be used alone or in combination with one or more other component ranges.

[0036] As used herein, the term "at least" includes the end value of the specified range. For example, "at least 10cm" includes the value 10cm.

[0037] As used herein, weight % means "percentage by weight" as the basis for calculating percentages. Unless otherwise stated, all % values ​​are calculated on a weight basis and relative to the total weight of the product in which the substance is contained.

[0038] As used herein, “substantially free” means not exceeding trace amounts, i.e., the amount of the substance is negligible. In one embodiment, “substantially free” means that the substance does not exceed 1,000 ppm, preferably not exceeding 100 ppm, more preferably not exceeding 10 ppm, and even more preferably not exceeding 1 ppm.

[0039] As used herein, the term "hydrocarbon group" refers to a group that includes at least one carbon (C) and one hydrogen (H). If a hydrocarbon group contains more than one carbon, these carbons are not necessarily linked together. For example, at least two carbons may be linked by suitable elements or groups. Therefore, a hydrocarbon group may contain heteroatoms. Suitable heteroatoms will be apparent to those skilled in the art and include, for example, sulfur, nitrogen, oxygen, phosphorus, and silicon. Non-limiting examples of such hydrocarbon groups include: alkyl groups, such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecanyl, octadecyl, nonadecanyl, eicosyl, and their isomers; cycloalkyl groups, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, 2-methylcyclopentyl, 2,3-dimethylcyclobutyl, 4-methylcyclobutyl, 3-cyclopentylpropyl, etc.; cycloalkenyl groups, such as cyclobutenyl, cyclopentenyl, cyclohexenyl, cycloheptenyl, cyclooctenyl, etc., and their isomers; cycloalkadienyl groups, such as cyclopentadienyl, cyclohexadienyl, cycloheptadienyl, etc.; aryl groups, such as phenyl, tolyl, xylyl, naphthyl, biphenyl, etc.; and aralkyl groups, such as benzyl, phenethyl, phenylpropyl, naphthylmethyl, etc. Preferably, the hydrocarbon group is aryl, heteroaryl, alkyl, cycloalkyl, aralkyl, or alkenyl. Preferably, the alkyl group is C10. 1-12 Alkyl, more preferably C 1-6 alkyl.

[0040] The general inventive concept described herein focuses on providing a polyvinyl alcohol-based polymer composition comprising an additive package, wherein the composition is suitable for, but not limited to, 3D printing, packaging, films, coatings, and water-soluble tools, and is also suitable for formulation as a raw material for the above applications, such as in the form of granules, pellets, and filaments.

[0041] In a first aspect, the present invention provides a polymer composition comprising a polymer (A) as described herein, a phosphite, and at least one additive selected from vitamin E and epoxidized soybean oil.

[0042] Polymer (A)

[0043] The polymer composition disclosed herein may comprise: a polymer (A) comprising about 60% to about 99% by weight based on the total weight of the composition. In a preferred embodiment, the polymer composition disclosed herein comprises about 90% to about 99% by weight, or about 95% to about 99% by weight, of polymer (A).

[0044] The polymer (A) disclosed herein can be described as polyvinyl alcohol (sometimes abbreviated as PVOH or PVA). Polyvinyl alcohol is a water-soluble polymer synthesized with the following formula, where n is an integer:

[0045] [CH2CH(OH)] n

[0046] Polyvinyl alcohol is a commercially available material, for example, under trade names. and POVAL TM For Sale. In the main industrial methods for manufacturing polyvinyl alcohol (PVA), polyvinyl acetate (PVAc) is first produced by the free radical polymerization of vinyl acetate. The resulting PVAc is then hydrolyzed under alkaline conditions, typically using methanol as a solvent, to produce PVA. The hydrolysis process can also be called the saponification process; the two terms are used interchangeably. Therefore, it is evident that PVA with different degrees of hydrolysis can be produced by this process; that is, PVA can be characterized by the degree of hydrolysis of the acetate groups in the PVAc starting material.

[0047] Therefore, the term "polyvinyl alcohol" as used herein has its usual meaning in the field of this disclosure, that is, it includes hydrolyzed products of polyvinyl acetate with different degrees of hydrolysis, and is not limited to polymers containing only [CH2CH(OH)] structural repeating units. Conversely, polyvinyl alcohol may also contain various proportions of residual vinyl acetate repeating units. Therefore, the terms "polyvinyl alcohol" and "[partially] hydrolyzed polyvinyl acetate" are used interchangeably in this disclosure.

[0048] The degree of hydrolysis of polyvinyl alcohol (PVA) is the proportion of ethylene alcohol units in all repeating units of the polymer, expressed as a mole percent (mol%). Therefore, the general structure of PVA is:

[0049] -[CH2CH(OH)] n -[CH2CH(OAc)] m

[0050] n is the amount of repeating units of ethylene alcohol in moles, and m is the amount of repeating units of vinyl acetate in moles. The degree of hydrolysis can be expressed by the following formula:

[0051]

[0052] Qualitative descriptions of the degree of hydrolysis are also commonly used in this disclosure. For example, the terms "partially hydrolyzed polyvinyl alcohol" and "fully hydrolyzed polyvinyl alcohol" are commonly used in this disclosure. However, there is no universally accepted boundary between these two terms based on the degree of hydrolysis in mol%. Nevertheless, for illustrative purposes only, in the United States, the Toxic Substances Control Act defines fully hydrolyzed polyvinyl alcohol as corresponding to a degree of hydrolysis of 98 mol% or greater.

[0053] Polyvinyl alcohol, such as the polymer (A) disclosed herein, can also be characterized as comprising structural units of formulas (I) and (II) in different proportions (repeating units indicated in parentheses herein):

[0054]

[0055] Among them, each R 1 Each R2 is independently hydrogen or alkyl, and each R2 is independently alkyl, more preferably C1-C6 alkyl. Therefore, a polymer containing about 66 mol% to about 79 mol% of the structural unit of formula (I) as defined above will have a degree of hydrolysis of about 66 mol% to about 79 mol%.

[0056] Polyvinyl alcohol (PVA) can also contain structural units other than those of formulas (I) and (II) above. PVA may, for example, contain unsaturated groups, such as carbon-carbon double bonds and carbonyl groups. Not to be bound by theory, such unsaturated groups may arise from polymer degradation, for example, during processing, particularly thermal processing. For instance, oxidation of the hydroxyl groups in PVA produces carbonyl groups. The hydroxyl and acetate groups in PVA may also undergo elimination reactions, producing water and acetic acid, respectively, and generating carbon-carbon double bonds in the polymer backbone. These unsaturated groups are often conjugated, thus causing polymer discoloration, which is generally undesirable.

[0057] Unsaturated groups may also be present due to the free radical polymerization of vinyl acetate used to prepare a polyvinyl acetate starting material, which is subsequently (partially) hydrolyzed to produce the polyvinyl alcohol / polymer (A) of this disclosure. For example, if an aliphatic aldehyde (such as acetaldehyde) is present during the free radical polymerization, a carbonyl group may be introduced into the end of the polymer. Conjugated polyene structures may also be present, which can be introduced by subsequent hydrolysis and thermal treatment processes. The conjugated groups produce UV absorption peaks near 230 nm, 280 nm, and 330 nm, depending on the length of the polyene group. The amount of unsaturated groups present in polymer (A) can be determined by UV-Vis spectrophotometry according to conventional procedures in the art.

[0058] Therefore, polyvinyl alcohol, such as polymer (A) of this disclosure, may further include structural units of formula (III):

[0059]

[0060] Where R 1 As defined above; R 3The atom is H or an alkyl group, preferably H or Me; and o is 0, 1, 2, or 3; wherein the asterisk indicates a connection point to a polyvinyl alcohol chain as defined herein. The polymer (A) may, for example, contain about 0 mol% to about 2 mol%, about 0 mol% to about 1.5 mol%, about 0 mol% to about 1 mol%, about 0 mol% to about 0.5 mol%, or about 0 to about 0.1 mol% of structural units of formula (III). In another preferred embodiment, the polymer (A) may be substantially free of structural units of formula (III). In another preferred embodiment, the polymer (A) may contain about 0.1 mol% to about 2 mol%, about 0.1 mol% to about 1 mol%, or about 0.1 mol% to about 0.5 mol% of structural units of formula (III).

[0061] Based on the total weight of the polymer composition, the polymer composition disclosed herein may comprise from about 60% by weight to about 99% by weight of polymer (A), wherein polymer (A) comprises, in each case, based on the molar number of polymer (A):

[0062] (i) Structural units of formula (I) of approximately 66 mol% to approximately 79 mol%:

[0063] and

[0064] (ii) Structural units of formula (II) of about 10 mol% to about 34 mol%:

[0065]

[0066] (iii) Structural units of formula (III) from about 0 mol% to about 2 mol%:

[0067]

[0068] Among them, each R 1 Each R is independently hydrogen or alkyl; 2 Independently alkyl; R 3 It is H or an alkyl group, preferably H or Me; and o is 0, 1, 2 or 3.

[0069] In a preferred embodiment, each R 1 Independently hydrogen or alkyl, more preferably H or C1-C6 alkyl. In a preferred embodiment, R 1 Independently, it is hydrogen, methyl, ethyl, propyl, butyl, pentyl, hexyl, or an isomer thereof. In another preferred embodiment, R 1 It is H. In one implementation, R 2 Independently, it is a C1-C6 alkyl group, more preferably methyl, ethyl, propyl, butyl, pentyl, hexyl, or isomers thereof. In a preferred embodiment, R 2It is Me. In another preferred embodiment, R 1 It is H, and R 2 It's me.

[0070] As described above, polyvinyl alcohol can be characterized by its degree of hydrolysis, a parameter corresponding to the proportion of alcohol repeating units in the polymer. Therefore, in a preferred embodiment of this disclosure, polymer (A) comprises about 70.0 mol% to about 74.0 mol%, preferably 71.5 mol% to about 73.5 mol% of structural units of formula (I). In another preferred embodiment, polymer (A) comprises about 75.0 mol% to about 79.0 mol%, preferably about 76.0 mol% to about 79.0 mol% of structural units of formula (I). Suitable polymers are commercially available.

[0071] In one preferred embodiment, polymer (A) comprises about 66 mol% to about 79 mol% of structural units of formula (I) and about 21 mol% to about 34 mol% of structural units of formula (II). In another preferred embodiment, polymer (A) is substantially composed of about 66 mol% to about 79 mol% of structural units of formula (I) and about 21 mol% to about 34 mol% of structural units of formula (II). In yet another preferred embodiment, polymer (A) comprises about 66 mol% to about 79 mol% of structural units of formula (I) and about 21 mol% to about 34 mol% of structural units of formula (II).

[0072] In another preferred embodiment, polymer (A) comprises about 70.0 mol% to about 74.0 mol% of structural units of formula (I) and about 26.0 mol% to about 30.0 mol% of structural units of formula (II). In another preferred embodiment, polymer (A) is substantially composed of about 70.0 mol% to about 74.0 mol% of structural units of formula (I) and about 26.0 mol% to about 30.0 mol% of structural units of formula (II). In another preferred embodiment, polymer (A) comprises about 70.0 mol% to about 74.0 mol% of structural units of formula (I) and about 26.0 mol% to about 30.0 mol% of structural units of formula (II).

[0073] In another preferred embodiment, polymer (A) comprises about 71.5 mol% to about 73.5 mol% of structural units of formula (I) and about 26.5 mol% to about 28.5 mol% of structural units of formula (II). In another preferred embodiment, polymer (A) is substantially composed of about 71.5 mol% to about 73.5 mol% of structural units of formula (I) and about 26.5 mol% to about 28.5 mol% of structural units of formula (II). In another preferred embodiment, polymer (A) comprises about 71.5 mol% to about 73.5 mol% of structural units of formula (I) and about 26.5 mol% to about 28.5 mol% of structural units of formula (II).

[0074] In another preferred embodiment, polymer (A) comprises about 75.0 mol% to about 79.0 mol% of structural units of formula (I) and about 21.0 mol% to about 25.0 mol% of structural units of formula (II). In another preferred embodiment, polymer (A) is substantially composed of about 75.0 mol% to about 79.0 mol% of structural units of formula (I) and about 21.0 mol% to about 25.0 mol% of structural units of formula (II). In another preferred embodiment, polymer (A) comprises about 75.0 mol% to about 79.0 mol% of structural units of formula (I) and about 21.0 mol% to about 25.0 mol% of structural units of formula (II).

[0075] In another preferred embodiment, polymer (A) comprises about 76.0 mol% to about 79.0 mol% of structural units of formula (I) and about 21.0 mol% to about 24.0 mol% of structural units of formula (II). In another preferred embodiment, polymer (A) is substantially composed of about 76.0 mol% to about 79.0 mol% of structural units of formula (I) and about 21.0 mol% to about 24.0 mol% of structural units of formula (II). In another preferred embodiment, polymer (A) comprises about 76.0 mol% to about 79.0 mol% of structural units of formula (I) and about 21.0 mol% to about 24.0 mol% of structural units of formula (II).

[0076] In this disclosure, the polymer (A) has a weight-average molecular weight (Mw) of about 26,000 to about 87,000 and a number-average molecular weight (Mn) of about 4,000 to about 45,000. Those skilled in the art will understand that the polydispersity (index) or PDI of the polymer can be calculated from Mw and Mn using the following formula:

[0077]

[0078] In a preferred embodiment, polymer (A) is further characterized by a peak molecular weight (Mp) of about 24,000 to about 40,000. The molecular weight of polymer (A) can be determined using polystyrene standards by gel permeation chromatography (GPC). Those skilled in the art will be able to select appropriate parameters. For example, the molecular weight of polymer (A) can be determined under the following conditions: 1 mL min -1 The flow rate and temperature were 40°C, with tetrahydrofuran as the solvent, an Agilent PLgelmixed B (300 x 7.5 mm, 10 μm) column, and Agilent EasiVial PS-H polystyrene standard as a control. Those skilled in the art will know that polyvinyl alcohol must first be reacetylated before GPC analysis. This reacetylation results in an increase in molecular weight, the factor of which depends on the original degree of hydrolysis. Therefore, to obtain the molecular weight of polyvinyl alcohol, the molecular weight obtained from GPC analysis must be divided by an appropriate factor corresponding to the original degree of hydrolysis. Those skilled in the art will be able to determine the appropriate factor. For example, the correction factor for polyvinyl alcohol with a degree of hydrolysis of 74% is 1.57, and the correction factor for polyvinyl alcohol with a degree of hydrolysis of 77.8% is 1.61.

[0079] Polymer (A) may also contain trace amounts of 1,2-ethylene glycol bonds, meaning that polymer (A) may further contain structural units of formula (IV):

[0080]

[0081] Where R 1 As defined above. It is not intended to be theoretically constrained, but it is assumed that this 1,2-ethylene glycol bond arises from trace head-to-tail:tail-to-head addition of vinyl acetate during its free radical polymerization to produce polyvinyl acetate, from which the polyvinyl alcohol polymer (A) is prepared. In a preferred embodiment, polymer (A) may contain about 0 mol% to about 2 mol%, about 0 mol% to about 1 mol%, about 0 mol% to about 0.5 mol%, or about 0 mol% to about 0.1 mol% of structural units of formula (IV). In another preferred embodiment, polymer (A) may be substantially free of structural units of formula (IV).

[0082] As described above, polyvinyl alcohol comprises repeating alcohol units and repeating acetate units, namely the structural units of formulas (I) and (II). Those skilled in the art will recognize that the repeating alcohol units and repeating acetate units may take on various different arrangements within the polymer chain. For example, the repeating alcohol units and repeating acetate units may be randomly distributed within the polymer chain, or similar repeating units may aggregate together to form blocks, as shown in the figure below:

[0083] ABABABABA [random]

[0084] AAABBBAAA[block]

[0085] Therefore, the polymer (A) of the present invention can have a random or block distribution of structural units of formula (II). This disclosure is not limited in this respect, and all distributions of structural units of formula (II) are considered herein. Those skilled in the art will know methods for measuring the distribution of residual acetate groups in polyvinyl alcohol. Briefly, the distribution can be measured indirectly by iodine absorbance or melting point. In another preferred embodiment, the distribution of structural units of formula (II) is measured by nuclear magnetic resonance (NMR) spectroscopy as described by Moritani and Fujiwara (Macromolecules (1977), 10:532-535), which is incorporated herein by reference.

[0086] Alternatively, polymer (A) may be defined as polyvinyl alcohol with a degree of hydrolysis of about 66 mol% to about 79 mol%.

[0087] Therefore, in one aspect, the present invention relates to a polymer composition comprising: (a) about 60 wt% to about 99 wt% of polyvinyl alcohol, wherein the polyvinyl alcohol has a degree of hydrolysis of about 66 mol% to about 79 mol%, a weight-average molecular weight (Mw) of about 26,000 to about 87,000, and a number-average molecular weight (Mn) of about 4,000 to about 45,000; and components (b)-(d) as defined above. In this respect, preferably, polymer (A) is polyvinyl alcohol with a degree of hydrolysis of about 70 mol% to about 74 mol%, more preferably about 71.5 mol% to about 73.5 mol%. In an alternative preferred embodiment, polymer (A) is polyvinyl alcohol with a degree of hydrolysis of about 75.0 mol% to about 79.0 mol%, more preferably about 76.0 to about 79.0 mol%.

[0088] The polymer compositions disclosed herein also comprise additives, namely about 0.05% by weight to about 10% by weight of phosphites as disclosed herein, and at least one additive selected from vitamin E and epoxidized soybean oil. The polymer compositions disclosed herein may further comprise one or more additives as disclosed herein. The additives disclosed herein may be collectively referred to as additive packages, and therefore, additive packages comprising the additives described herein are also contemplated herein. Additive packages may be prepared as separate ingredients and subsequently combined with polymer (A) to form the polymer compositions of this disclosure. Alternatively, the additives and polymer (A) may be combined for the first time during compounding. Additive packages may be provided in a concentrated form such that the amount of each component of the polymer compositions of this invention disclosed herein is achieved after the additive packages are combined with polymer (A).

[0089] Surprisingly, the polymer compositions of this disclosure, including the additive packages disclosed herein, provide thermoplastic materials with one or more of the following advantageous properties: good melt and flow behavior; cold water solubility; good hot workability; the ability to be formulated into granules, pellets, and filaments; and good thermal stability, particularly resistance to discoloration, degradation, and / or decomposition during repeated heat treatment operations. Furthermore, the polymer compositions of this disclosure have been found to have good compatibility with 3D printing processes, such as fused deposition modeling (FDM), including filament fabrication and fused particle fabrication techniques. In particular, the polymer compositions of this disclosure can be readily formulated into raw materials suitable for this process, such as filaments having one or more of good ductility, flexibility, and tensile stress. Other advantageous properties related to 3D printing include: good adhesion between printed layers, little or no bubbling, little or no warping, and little or no nozzle clogging.

[0090] For ease of reference, the additives and other features of this disclosure are now discussed under the appropriate section headings. However, the teachings under each section are not limited to the section in which they are located. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0091] Phosphite additives

[0092] The polymer compositions disclosed herein comprise phosphites selected from the group consisting of formulas (IV) and (V):

[0093]

[0094]

[0095] Where R a R b R c and R d Each is an independent hydrocarbon group. These phosphite additives are commercially available, for example, from BASF. The product sold under the product name.

[0096] In a preferred embodiment of this disclosure, R a R b R c and R d Each is independently an aryl group substituted with one or more alkyl groups. In another preferred embodiment, R a R b R c and R dEach is independently selected from alkyl groups, and phenyl groups substituted with one or more alkyl groups. In another preferred embodiment, R a R b R c and R d Each is independently a phenyl group substituted with one or more butyl groups. In another preferred embodiment, R a R b R c and R d Each is a phenyl group that is independently substituted with one or more tert-butyl groups.

[0097] Examples of suitable phosphite additives include bis(2,4-di-tert-butylphenol) pentaerythritol diphosphite, bis(2,4-di-tert-butyl-6-methylphenyl)-ethyl phosphite, bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, and tris(2,4-di-tert-butylphenyl) phosphite. The structures and trade names of these additives are shown in the table below:

[0098]

[0099]

[0100] In a preferred embodiment, the phosphite disclosed herein is tris(2,4-di-tert-butylphenyl) phosphite (Irgafos 168).

[0101] Vitamin E and epoxidized soybean oil

[0102] The polymer composition disclosed herein contains at least one additive selected from vitamin E and epoxidized soybean oil. Vitamin E comprises eight fat-soluble compounds, including four tocopherols and four tocotrienols. Both tocopherols and tocotrienols exist in alpha (α), beta (β), gamma (γ), and delta (δ) forms, depending on the number and position of methyl groups on the chromoalkanoyl ring.

[0103] The four tocopherols can be represented by the following general formula:

[0104]

[0105] For α-tocopherol, X and Y are each Me; for β-tocopherol, X is Me and Y is H; for γ-tocopherol, X is H and Y is Me; for δ-tocopherol, X and Y are each H.

[0106] The four tocotrienols can be represented by the following general formula:

[0107]

[0108] X and Y are as defined above.

[0109] Vitamin E is naturally occurring and is typically derived from (extracted, purified, or concentrated) plant sources, particularly vegetable oils such as common wheat (Triticum vulgare, wheat) germ oil. Therefore, in a preferred embodiment of this disclosure, vitamin E is obtained from a plant source, preferably from common wheat. The most abundant and active form of vitamin E in the human body is α-tocopherol. As can be clearly seen from the above structure, tocopherol contains three chiral centers, one at C2 of the chromoalkyl alcohol ring, and the other two in the side chains at C4' and C8'. The naturally occurring form of α-tocopherol is D-α-tocopherol (also known as RRR-α-tocopherol). Vitamin E (usually α-tocopherol) can also be prepared synthetically. In this case, the synthetic vitamin E is typically prepared as a racemic mixture of α-tocopherol, referred to as DL-α-tocopherol or all-rac-α-tocopherol. Synthetic α-tocopherol or α-tocopherol obtained from natural sources can also be provided in the form of esters, such as its acetate, succinate, nicotinic acid ester, and phosphate esters. Therefore, in a preferred embodiment of this disclosure, vitamin E comprises D-α-tocopherol and / or its esters. The esters of D-α-tocopherol may be selected from D-α-tocopherol acetate, D-α-tocopherol succinate, D-α-tocopherol nicotinate, and D-α-tocopherol phosphate. In another preferred embodiment, vitamin E is synthetic vitamin E, preferably DL-α-tocopherol and / or its esters. The esters of DL-α-tocopherol may be selected from the group consisting of DL-α-tocopherol acetate, DL-α-tocopherol succinate, DL-α-tocopherol nicotinate, and DL-α-tocopherol phosphate.

[0110] In a preferred embodiment, the vitamin E disclosed herein may be in the form of a mixture comprising vitamin E and one or more fatty acids. There is no need to limit the nature of the fatty acids; examples include palmitic acid, palmitoleic acid, stearic acid, oleic acid, linoleic acid, α-linoleic acid, arachidic acid, eicosenoic acid, benzyl acid, and mixtures thereof. Therefore, in a preferred embodiment, vitamin E is in the form of a mixture comprising D-α-tocopherol and / or its esters and one or more fatty acids. In a preferred embodiment, D-α-tocopherol and / or its esters are present in the mixture in an amount from about 0.1% by weight to about 0.75% by weight, preferably from about 0.25% by weight to about 0.5% by weight, based on the total weight of the mixture.

[0111] According to any embodiment disclosed herein, vitamin E may preferably be present in the polymer composition of the present disclosure in an amount of about 0.001 wt% to about 2 wt%, about 0.001 wt% to about 1 wt%, about 0.001 wt% to about 0.2 wt%, about 0.01 wt% to about 0.2 wt%, or about 0.05 wt% to about 0.2 wt% of the total amount of the polymer composition.

[0112] Epoxidized soybean oil is a commercially available additive obtained by the epoxidation of soybean oil, typically by epoxidizing unsaturated soybean oil with a high iodine value using hydrogen peroxide and organic acids such as formic acid or acetic acid. Epoxidized soybean oil can be identified by CAS-No.: 8013-07-8. In a preferred embodiment of this disclosure, the polymer composition comprises about 0.001 wt% to about 5 wt%, about 0.001 wt% to about 2 wt%, about 0.01 wt% to about 2 wt%, about 0.01 wt% to about 1 wt%, or about 0.01 wt% to about 0.5 wt% of the total polymer composition.

[0113] In a preferred embodiment, the polymer composition disclosed herein comprises vitamin E and epoxidized soybean oil. Therefore, the various ranges of vitamin E amounts disclosed above can be combined with the various ranges of epoxidized soybean oil amounts disclosed above. For example, the polymer composition disclosed herein preferably comprises about 0.001 wt% to about 2 wt% of vitamin E and about 0.001 wt% to about 5 wt% of epoxidized soybean oil, or about 0.05 wt% to about 0.2 wt% of vitamin E and about 0.01 wt% to about 0.5 wt% of epoxidized soybean oil.

[0114] PEG-grafted polyvinyl acetate copolymer

[0115] The polymer composition disclosed herein comprises about 0% to about 10% by weight of a PEG-grafted polyvinyl acetate copolymer having a degree of hydrolysis of about 30 mol% to about 98 mol%, a weight-average molecular weight (Mw) of about 5,000 to about 40,000, and a number-average molecular weight (Mn) of about 1,000 to about 20,000. Within the technical field of this disclosure, the PEG-grafted polyvinyl acetate copolymer can also be described as an internally plasticized polyvinyl alcohol.

[0116] In a preferred embodiment, the PEG-grafted polyvinyl acetate copolymer of this disclosure is a graft copolymer in which partially hydrolyzed polyvinyl acetate / alcohol links are grafted onto the backbone of a polyethylene glycol (PEG) polymer chain. A non-limiting, idealized structure of such a PEG-grafted polyvinyl acetate copolymer can be shown as follows, where an asterisk denotes the connection point of a repeating structural unit:

[0117]

[0118] In one preferred embodiment of this disclosure, the degree of hydrolysis of the PEG-grafted polyvinyl acetate copolymer is about 33.0 mol% to about 37.0 mol%, preferably 35.0 mol%. In another preferred embodiment, the degree of hydrolysis of the PEG-grafted polyvinyl acetate copolymer is about 42.0 mol% to about 45.0 mol%, preferably 43.0 mol%. In another preferred embodiment, the degree of hydrolysis of the PEG-grafted polyvinyl acetate copolymer is about 78.0 mol% to about 88.7 mol%, preferably about 80.0 mol% to about 88.7 mol%. In yet another preferred embodiment, the degree of hydrolysis of the PEG-grafted polyvinyl acetate copolymer is about 84.0 mol% to about 98.0 mol%, preferably about 93.0 mol% to about 98.0 mol%.

[0119] PEG-grafted polyvinyl acetate copolymers can also be characterized based on the proportion of residual acetate repeating units in the polymer. For example, in a preferred embodiment, the level of residual acetate in the PEG-grafted polyvinyl acetate copolymer is from about 20.0% to about 27.6%. In another preferred embodiment, the level of residual acetate in the PEG-grafted polyvinyl acetate copolymer is from about 3.8% to about 12.8%.

[0120] The PEG-grafted polyvinyl acetate copolymer may be present in the polymer composition of this disclosure in an amount of about 0% to about 10% by weight, about 0% to about 5% by weight, or about 0% to about 2% by weight of the polymer composition. In a preferred embodiment, the PEG-grafted polyvinyl acetate copolymer may be present in the polymer composition of this disclosure in an amount of about 0.01% to about 10% by weight, about 0.01% to about 5% by weight, or about 0.01% to about 2% by weight of the polymer composition. In another preferred embodiment, the PEG-grafted polyvinyl acetate copolymer may be present in the polymer composition of this disclosure in an amount of about 0.1% to about 10% by weight, about 0.1% to about 5% by weight, or about 0.1% to about 2% by weight of the polymer composition.

[0121] In a preferred embodiment of this disclosure, the PEG-grafted polyvinyl acetate copolymer comprises about 1% to about 70% by weight, more preferably about 15% to about 56% by weight, polyethylene glycol (PEG), based on the total weight of the PEG-grafted polyvinyl acetate copolymer.

[0122] The PEG-grafted polyvinyl acetate copolymers suitable for use in this disclosure are commercially available. The PEG-grafted polyvinyl acetate copolymers may be in the form of an aqueous solution. In a preferred embodiment, one or more organic solvents may also be present in the aqueous solution. There are no limitations on the nature of the organic solvents, and those skilled in the art will be able to select organic solvents compatible with the PEG-grafted polyvinyl acetate copolymers of this disclosure. In some non-limiting examples, the organic solvent may be an alcohol, such as ethanol, methanol, or isopropanol. If the PEG-grafted polyvinyl acetate copolymer is in the form of an aqueous solution, the total solids content of the solution may be: about 10% by weight to about 60% by weight, about 20% to about 50% by weight / volume (w / v), or about 30% to about 40% (w / v), based on the total volume of the aqueous solution.

[0123] In a preferred embodiment, the viscosity of a 4% by weight aqueous solution of PEG-grafted polyvinyl acetate copolymer can be from about 4.5 mPa·s to about 5.5 mPa·s when measured by a Brookfield viscometer RVT type with rotor No. 3 at a shear rate of 20 rpm at about 23 + / - 0.2 °C.

[0124] Other additives

[0125] In a preferred embodiment, the polymer composition of this disclosure, in addition to those discussed above, includes one or more additives. Such additives may be plasticizers, such as their polyol derivatives, like ethylene glycols such as mono-, di-, tri-, and polyethylene glycols, glycerols, glycols, tri-ols, and polyols. Other non-limiting examples of additives that may also be present in the polymer composition include lubricants, anti-blocking agents, defoaming additives, oxidative stabilizers, melt stabilizers, pigments, dyes, fillers, and other polymer compounds. In a preferred embodiment, the polymer composition of this disclosure further comprises stannates. In a preferred embodiment, the polymer composition comprises stannates selected from the group consisting of sodium stannate, calcium stannate, zinc stannate, zinc hydroxystannate, and calcium hydroxystannate. In any of the foregoing embodiments, the additives are present in the polymer composition of this disclosure in an amount of about 0% to about 10% by weight, about 0% to about 5% by weight, or about 0% to about 2% by weight.

[0126] Composition and its preparation method

[0127] The polymer compositions disclosed herein can be further illustrated by the non-limiting embodiments listed in Table 1.

[0128] Table 1

[0129]

[0130] 1 Degree of hydrolysis: 71.5 mol% to 73.5 mol%.

[0131] 2 Tris(2,4-di-tert-butylphenyl) phosphite (Irgafos 168)

[0132] In a preferred embodiment of the invention, water may be present in the polymer composition. For example, water may be present in the composition due to the presence of water in the components prior to mixing, or water may be added to the composition separately. In a preferred embodiment, the polymer composition of this disclosure contains about 10% by weight or less, about 5% by weight or less, about 2% by weight or less, about 1% by weight or less, or about 0.6% by weight or less of water, based on the total weight of the polymer composition. In another preferred embodiment, the polymer composition contains at least about 0.1% by weight of water. In another preferred embodiment, the polymer composition of this disclosure contains about 0.1% by weight to about 10% by weight of water, about 0.1% by weight to about 5% by weight of water, about 0.1% by weight to about 2% by weight, about 0.1% by weight to about 1% by weight, or about 0.1% by weight to about 0.6% by weight of water, based on the total weight of the polymer composition. In another preferred embodiment, the polymer composition contains about 0.4% by weight to about 0.6% by weight of water, based on the total weight of the polymer composition. Therefore, based on the total weight of the polymer composition, any composition of embodiments A to G shown in Table 1 may further contain about 0.1 wt% to about 10 wt% of water, about 0.1 wt% to about 5 wt% of water, about 0.1 wt% to about 2 wt% of water, about 0.1 wt% to about 1 wt% of water, or about 0.1 wt% to about 0.6 wt% of water.

[0133] In a preferred embodiment, it may be necessary to reduce the moisture content of the polymer composition to a level suitable for compounding (e.g., forming granules or filaments), downstream processing, and / or 3D printing. For example, a low moisture content may be preferred when preparing granules or filaments to minimize potentially undesirable bubble formation in subsequent applications. Those skilled in the art will be able to select a method for drying the polymer composition, specifically within their common sense. Polymer granules may, for example, be dried under vacuum.

[0134] Those skilled in the art will also know the methods for determining the water content of the polymer compositions of this disclosure. The Karl Fischer method for determining moisture content is particularly useful in the context of this disclosure and is described in more detail in ISO 15512:2019, the contents of which are incorporated herein by reference.

[0135] The polymer compositions disclosed herein can be compounded into various forms commonly used in the field, and there are no limitations in this regard. The polymer compositions can be compounded into any solid form commonly used in industry, and those skilled in the art will be able to select a suitable form for downstream processing and manufacturing. In a preferred embodiment, the polymer compositions of this disclosure may be in the form of extrudates. Specifically, suitable equipment for polymer compounding and extrusion is within the general knowledge of those skilled in the art, who will be able to select suitable equipment, and this disclosure is not limited in this respect. In a preferred embodiment, the polymer compositions may be in the form of extruded filaments, granules, powders, flakes, or pellets. If the polymer composition is in granule form, in a preferred embodiment, the diameter of the granules may be from about 1 mm to about 5 mm, preferably from about 2 mm to about 4 mm.

[0136] The polymer compositions disclosed herein have been found to be particularly suitable for thermoplastic processing. When preparing for downstream applications, polymer compositions typically undergo multiple heat treatment steps. For example, mixtures of polymers and additives are often first compounded into forms such as granules, flakes, or pellets. During compounding, the polymer and one or more additives (e.g., as an additive package) are mixed together in a molten state, then extruded and cooled. These forms are then typically used in production processes, where they are remelted for use, for example, injection molding or extrusion, and then cooled. Forms such as granules, flakes, or pellets can also be further compounded into other forms, such as filaments for 3D printing technologies, such as fused deposition modeling, which includes filament fabrication and molten particle fabrication technologies. Thus, the polymer compositions undergo multiple melt-cooling cycles, which, if left unmitigated, can lead to degradation, decomposition, and / or discoloration. In particular, polyvinyl alcohol may be particularly susceptible to thermally induced decomposition via mechanisms already discussed above (e.g., oxidation and the elimination of water and acetic acid). This decomposition reaction can cause undesirable discoloration of the polymer (typically yellow or amber). The polymer compositions of this disclosure have been found to have particularly good thermal stability during multiple heat treatment steps at temperatures typically used for processing polyvinyl alcohol, while maintaining good melt and flow properties.

[0137] Other aspects of this disclosure provide a method for preparing the compositions described herein. In a preferred embodiment of this disclosure, a premix comprising components (a) to (d) and optional other additives as described herein is first formed. The premix can be prepared by mixing the polymer (A) and the additives of this disclosure together in a high-speed mixer. The polymer (A) and the additives can be combined in a high-speed mixer, or the additives can be first formulated as an additive package and then combined with the polymer (A) during the formation of the premix.

[0138] The polymer composition of this disclosure in premix form can then be extruded through a die. Specifically, the equipment used for extruding the polymer is within the general knowledge of those skilled in the art, who will be able to select suitable equipment. In a preferred embodiment of this disclosure, the premix is ​​extruded from a twin-screw extruder having three melting zones. Typically, the temperature of the melting zones is preferably below the decomposition temperature, which is typically from about 260°C to about 380°C. Thus, in a preferred embodiment, the temperature of the melting zones is independently from about 150°C to about 240°C, preferably from about 170°C to about 220°C. In a preferred embodiment, the extrusion speed can be from about 100 rpm to about 200 rpm. The feed rate can be about 0.1 mm / s. -1 Approximately 1 mm -1 The diameter of the die can be from about 1 mm to about 10 mm. Cooling of the extrudate is usually required. The extruded polymer is typically cooled in water; however, due to the water solubility of polyvinyl alcohol polymers, in a preferred embodiment, the extrudate is air-cooled. The extruded polymer composition (e.g., granules) can be stored before downstream use, and in a preferred embodiment, the extruded polymer is stored in a moisture-proof bag.

[0139] As described above, the polymer compositions of this disclosure can be extruded into various forms, such as granules, pellets, and filaments. These forms may then be processed into other forms. In a preferred embodiment, filaments can be formed directly from the premix; in other cases, filaments can be formed from the polymer compositions of this disclosure in granular or pellet form. Filaments are commonly used in 3D printing processes, such as fused deposition modeling, which includes filament fabrication and fused particle fabrication techniques.

[0140] As described above, it may be preferable to reduce the moisture content of the polymer composition (e.g., granules) to an acceptable level before further processing (e.g., forming filaments). Therefore, in a preferred embodiment, the polymer composition (preferably in granular form) is dried before forming filaments. Drying can be carried out in a conventional air-circulating oven and / or under vacuum. As described above, the moisture content can be determined using the Karl Fischer method. The dried granules can be stored in moisture-proof bags, which may contain silica desiccant.

[0141] Filaments can be prepared from granules (preferably dried granules as described above) by transferring them into a single-screw extruder with four melting zones. A non-limiting example of such an extruder is the 3devo Composer 350. The temperature of the melting zones can vary depending on the melting temperature of the granules, and those skilled in the art will be able to select an appropriate temperature based on this. In a preferred embodiment, the temperature of the melting zones is independently from about 150°C to about 240°C, preferably from about 160°C to about 200°C. The screw speed can be from about 3 rpm to about 8 rpm, and the power of the cooling fan can be from about 0 to about 100%. In a preferred embodiment, water cooling is avoided. Therefore, in a preferred embodiment, the extruded filaments are air-cooled. As the filaments are extruded from the extruder nozzle, they can be arranged between traction rollers to achieve the desired filament diameter. In a preferred embodiment, the diameter of the filaments can be from about 1 mm to about 5 mm, preferably from about 2 mm to about 4 mm. The filaments are typically wound on spools for storage and distribution to the end user.

[0142] The polymer compositions of the present invention can be used in a wide range of industrial applications and are not limited thereto. Polyvinyl alcohol-based polymers are non-toxic, water-soluble, and biodegradable, and are therefore attractive in 3D printing. Polyvinyl alcohol-based polymers are commonly used as support materials for 3D printing of intricate three-dimensional geometries. Therefore, in other aspects, this disclosure provides the use of the compositions disclosed herein in 3D printing. Specifically, the polymer compositions of this disclosure can be used as water-soluble carriers in 3D printing. In a further aspect of this disclosure, 3D printed articles prepared from the compositions disclosed herein are also provided. This disclosure is not limited to specific 3D printing technologies, and the polymer compositions disclosed herein can be used, for example, for fused deposition modeling (FDM) or fused particle manufacturing (FPM) technologies. In either or both of FDM and FPM technologies, it is preferable to dry the granules or filaments containing the polymer compositions of this disclosure before printing begins. Thus, the granules and filaments can be dried, for example, in a conventional air-circulating oven. In a preferred embodiment, the oven temperature can be from about 35°C to about 60°C. Therefore, based on the total weight of the polymer composition, the granules or filaments may contain about 0.1 wt% to about 10 wt% water, about 0.1 wt% to about 5 wt% water, about 0.1 wt% to about 2 wt% water, about 0.1 wt% to about 1 wt% water, or about 0.1 wt% to about 0.6 wt% water. In another preferred embodiment, based on the total weight of the polymer composition, the granules or filaments contain about 0.4 wt% to about 0.6 wt% water.

[0143] Those skilled in the art will be able to select an appropriate printing temperature. In particular, they will be able to select a temperature that minimizes the decomposition and / or discoloration of the polymer composition. Therefore, in a preferred embodiment, the nozzle temperature for 3D printing can be less than or equal to about 250°C. In another preferred embodiment, the nozzle temperature for 3D printing can be from about 160°C to about 250°C.

[0144] In applications such as 3D printing, it may be necessary to remove printed support structures containing polyvinyl alcohol-based polymers with minimal or no heating and / or stirring or agitation. This reduces procedural complexity by eliminating the need for mixing and heating equipment and can also be more energy-efficient. In amateur use, it may be particularly desirable to dissolve the support structure in tap water without stirring or agitation. The polymer compositions of this disclosure have been found to have good cold water solubility and may dissolve without stirring. The dissolution temperature of polyvinyl alcohol is typically set below the cloud point of the specific polymer, and as previously stated, it is generally preferred that the polymer be cold water soluble, i.e., soluble at or below ambient temperature. Those skilled in the art will be able to select a suitable dissolution temperature without undue burden. Therefore, in a preferred embodiment, the polymer compositions of this disclosure are soluble in water at a temperature of about 5°C to about 30°C, preferably about 5°C to about 25°C, preferably about 5°C to about 15°C, preferably about 10°C. Furthermore, it is generally desirable that the support structure dissolves within a practically feasible timescale after immersion in water and / or leaves no residue. For example, in one preferred embodiment, the polymer composition of this disclosure dissolves in water at a temperature of about 5°C to about 25°C in less than 24 hours. In another preferred embodiment, the polymer composition of this disclosure dissolves in water at a temperature of about 5°C to about 25°C in less than 6 hours, more preferably in less than 4 hours. In another preferred embodiment, the polymer composition of this disclosure dissolves in water at a temperature of about 5°C to about 15°C in less than 24 hours, more preferably in less than 6 hours, and even more preferably in less than 4 hours. In yet another preferred embodiment, the polymer composition of this disclosure dissolves in water at a temperature of about 10°C in less than 24 hours, less than 6 hours, or less than 4 hours. In any of the above embodiments, it may be further preferred that the polymer composition dissolves without stirring.

[0145] In 3D printing, starting materials (such as polymer pellets and filaments) have many other desirable properties. For example, it is desirable for the polymer to print in a manner that does not introduce defects (e.g., bubbles / foaming) in the printing material. Additionally, it is generally desirable for the printed structure to retain its shape without warping after printing and cooling. Good adhesion between printed layers is also generally desirable. Other properties of the polymer raw material (e.g., filaments) during printing (e.g., smoothness and roundness) can affect the quality of the printed article. Therefore, filaments with smooth surfaces, regular circular cross-sections, and / or consistent diameters are often preferred. For filaments, it is also generally desirable for them to pass smoothly through the print nozzle without causing clogging. Furthermore, it is generally desirable for the filaments to have flexibility and tensile stress suitable for 3D printing processes, for example, so that the filaments do not break due to brittleness during printing. The polymer compositions of this disclosure have been found to have good properties in one or more of the above-mentioned characteristics and to maintain good melt and flow behavior as well as water solubility.

[0146] In addition to 3D printing, the polymer compositions disclosed herein can also be used in packaging, films, coatings, or water-soluble tools. In these applications, polyvinyl alcohol-based polymers are particularly attractive due to their water solubility, low permeability to gases such as oxygen, resistance to organic solvents, non-toxicity, and biodegradability.

[0147] After a general description of this disclosure, further understanding can be obtained by referring to certain specific embodiments shown below, which are for illustrative purposes only and are not intended to be all-encompassing or limiting, unless otherwise stated.

[0148] Example

[0149] The formulations shown in Table 2 were prepared according to the general procedure listed below.

[0150] General procedure for compounding into granules

[0151] Combine and thoroughly mix the components shown in Table 2 in a high-speed mixer. Transfer the resulting premixed composition to a twin-screw extruder with three melting zones at 160-220°C. The feed rate is 0.1-1 mm / s. -1 The process involves extruded material through a 5mm diameter die at a speed of 100-200 rpm and then air-cooled. The resulting pellets have a size of approximately 2-4mm. The pellets are then stored in moisture-proof bags.

[0152] General procedure for preparing filaments

[0153] The 2-4 mm granules prepared by the above method were dried in a conventional air-circulating oven for several hours until an acceptable moisture content was achieved, considered to be less than 0.6% by weight. The moisture content was checked using a Mettler automated coulometric KF titrator C30, which heats the granular sample in a sealed sample container to 150°C, then extracts and titrates any water vapor to determine the moisture content, using HYDRANAL as a control. Once dried, the granules can be stored in moisture-proof bags containing silica desiccant packets, thus requiring no further drying when the material is removed from the fresh bag. The bags are stored indoors under dry conditions, and opened bags are resealed after use.

[0154] The dried granules are transferred to a single-screw extruder with four melting zones ranging from 160-200°C, the temperatures determined by the granules' melting point, which is between 150-180°C. The screw speed is 3-8 rpm, with a cooling fan used if necessary. Water cooling is avoided. After filaments are extruded from the extruder nozzles, they are arranged between traction rollers to obtain filaments with a diameter of 2.85 mm. The filaments are then wound onto a spool.

[0155] Table 2

[0156]

[0157] 1 Degree of hydrolysis: 71.5-73.5 mol%

[0158] 2 Degree of hydrolysis: 76.0-79.0 mol%

[0159] 3 Tris(2,4-di-tert-butylphenyl) phosphite (Irgafos 168)

[0160] a 5% by weight PEG8000 and 2% by weight Irganox 1010

[0161] b 2% by weight of Irganox 1010

[0162] c 2% by weight Flamtard S

[0163] d 1% by weight of PEG8000 and 2% by weight of Irganox 1010

[0164] The melt flow index (MFI) of formulations is measured according to ISO 1133, the contents of which are incorporated herein by reference. The MFI is measured using a Davenport automated flow rate timer. This method measures material extruded through a specified die in a vertical cylinder under a static load of 2.16 kg or 5 kg applied to the piston top. The material is loaded into the cylinder at the test temperature, given a certain time to melt and fuse, and then the extruded material is collected and weighed. The collection time is 1 minute, and the test is repeated 5 times. The average of the 5 repeated tests is calculated and the result is reported in g / 10 min.

[0165] At 190°C, the formulations according to the present invention were found to exhibit good melting and flow behavior and minimal discoloration / degradation. Formulations outside the scope of the present invention exhibited unstable MFI values ​​over time, as well as degradation / discoloration.

[0166] Water-soluble

[0167] To assess water solubility, weigh 3-5 g of granules containing the formulation in Table 2 and transfer them to a container filled with 300 mL of tap water. Stir vigorously at 500 rpm and monitor the solution. Measure the time from the start of dissolution (determined by observing a color change in the tap water) to complete dissolution. Observe the swelling of the granules during the initial 10-20 minutes and make qualitative observations based on visual observation. Measurements can also be made on filaments by clamping the filaments and immersing them in water, then measuring the dissolution time and swelling as described above.

[0168] The performance was compared to a baseline, where the baseline dissolution time was 145 minutes for complete dissolution and 10 minutes for swelling. Measurements approximately equal to or less than the baseline time were considered to demonstrate good performance. Dissolution and swelling after heat treatment at 190°C were also measured. The measurement results are summarized in Table 3.

[0169] Table 3

[0170]

[0171] ND: Not measured

[0172] 3D printing experiment

[0173] The filaments prepared as described above were printed in a fused deposition modeling printer. The printing temperature was 160–250 °C, and the filaments used had a water content of 0.5–0.6% by weight. The bed temperature was room temperature to 60 °C. The 3D printing performance of the filaments containing each formulation from Examples 1 to 12 was qualitatively evaluated based on printing capability, filament shape, and the quality of the printing material (e.g., the presence of defects such as bubbles). These observations are summarized in Table 4.

[0174] Table 4

[0175] Example Observation results 1 Printing attempt failed 2 Printing was successful, but there are many air bubbles. 3 Printing was successful, but there are many air bubbles. 4 Printing successful, but some air bubbles; the filament shape is poor. 5 Printing successful, with some air bubbles; the filament shape is good. 6 Printing attempt failed 7 Printing successful, with very few air bubbles; fine filament shape is good. 8 Printing successful, with very few air bubbles; fine filament shape is good. 9 Printing successful, with very few air bubbles; fine filament shape is good. 10 Printing successful, with a few air bubbles; fine filament shape is good. 11 Printing successful, with a few air bubbles; fine filament shape is good. 12 Printing successful, with a few air bubbles; fine filament shape is good.

[0176] Therefore, the formulations according to the present invention have been found to have good performance in fused deposition modeling, which includes filament fabrication technology and fused particle fabrication technology (3D printing).

[0177] Tensile properties of filaments

[0178] The tensile properties of filaments containing the formulations in Table 2 were measured according to the methods disclosed in ASTM D638-14 and ISO 527-2 (the contents of which are incorporated herein by reference). Specifically, approximately 14 cm of each filament was cut for analysis at a gauge length of 10 cm, using a 5 kN load cell and with a rod specimen as a reference, as specified in ASTM D638-14. The sample diameter was recorded and added to the method before starting the test. Measurements were performed in a temperature-controlled chamber at 20°C. The samples were dried at 60°C for 5 hours and then stored in a desiccator until testing. Table 5 summarizes the average tensile stress values ​​at fracture.

[0179] Table 5

[0180]

[0181] Based on the tensile stress at fracture, Examples 5, 7, 8, and 9 are considered to have good performance. Inference from the stress / strain curves suggests that Examples 2, 3, and 4 have high ductility.

[0182] Various modifications and variations to the aspects of this invention described herein will be apparent to those skilled in the art without departing from the scope and spirit of the invention. Although the invention has been described in conjunction with specific preferred embodiments, it should be understood that the claimed invention should not be unduly limited to these specific embodiments. In fact, various modifications to the described modes of implementing the invention that will be apparent to those skilled in the art are intended to be covered within the scope of the appended claims.

Claims

1. A thermally extrudable polymer composition, wherein in each case, based on the total weight of the polymer composition, it comprises: (a) 60% to 99% by weight of polymer (A), wherein polymer (A) in each case comprises, based on the total number of moles of polymer (A): (i) Structural units of formula (I) ranging from 66 mol% to 79 mol%: (I); sum (ii) Structural units of formula (II) ranging from 10 mol% to 34 mol%: (II); Among them, each R 1 Each R is independently hydrogen or alkyl. 2 Independently alkyl; and The polymer (A) has a weight-average molecular weight (Mw) of 26,000 to 87,000 and a number-average molecular weight (Mn) of 4,000 to 45,000. (b) 0.05% to 10% by weight of phosphites selected from the group consisting of formulas (V) and (VI): （V） (WE) Where R a R b R c and R d Each is an independent hydrocarbon group; (c) At least one additive selected from: (i) Vitamin E; and (ii) Epoxidized soybean oil; and (d) 0.01 to 10% by weight of PEG-grafted polyvinyl acetate copolymer, wherein the degree of hydrolysis of the polyvinyl acetate copolymer is 30 mol% to 98 mol%, the weight-average molecular weight (Mw) is 5,000 to 40,000, and the number-average molecular weight (Mn) is 1,000 to 20,000.

2. The polymer composition according to claim 1, wherein the composition comprises 90% to 99% by weight of polymer (A).

3. The polymer composition according to claim 1, wherein R 1 For H.

4. The polymer composition according to claim 1, wherein R 2 For Me.

5. The polymer composition according to claim 1, wherein the polymer (A) comprises 21 mol% to 34 mol% of structural units of formula (II).

6. The polymer composition according to claim 1, wherein the polymer (A) comprises 70.0 mol% to 74.0 mol% of structural units of formula (I).

7. The polymer composition according to claim 6, wherein the polymer (A) comprises 71.5 mol% to 73.5 mol% of structural units of formula (I).

8. The polymer composition according to any one of claims 1 to 5, wherein the polymer (A) comprises 75.0 mol% to 79.0 mol% of the structural unit of formula (I).

9. The polymer composition according to claim 8, wherein the polymer (A) comprises 76.0 mol% to 79.0 mol% of structural units of formula (I).

10. The polymer composition according to any one of claims 1 to 5, wherein the PEG-grafted polyvinyl acetate copolymer comprises 1% to 70% by weight of PEG based on the total weight of the PEG-grafted polyvinyl acetate copolymer.

11. The polymer composition of claim 10, wherein the PEG-grafted polyvinyl acetate copolymer comprises 15% to 56% by weight of PEG based on the total weight of the PEG-grafted polyvinyl acetate copolymer.

12. The polymer composition according to any one of claims 1 to 5, wherein the PEG-grafted polyvinyl acetate copolymer is in aqueous solution form.

13. The polymer composition of claim 12, wherein the PEG-grafted polyvinyl acetate copolymer is present in the aqueous solution in an amount of 4% by weight, and the viscosity of the solution is 4.5 mPa·s to 5.5 mPa·s when measured by a Brookfield viscometer RVT type with rotor No. 3 at a shear rate of 20 rpm at 23 ± 0.2 °C.

14. The polymer composition according to any one of claims 1 to 5, wherein the PEG-grafted polyvinyl acetate copolymer has a degree of hydrolysis of 33.0 mol% to 45.0 mol%.

15. The polymer composition of claim 14, wherein the PEG-grafted polyvinyl acetate copolymer has a degree of hydrolysis of 42.0 mol% to 45.0 mol%.

16. The polymer composition of claim 14, wherein the PEG-grafted polyvinyl acetate copolymer has a degree of hydrolysis of 43.0 mol%.

17. The polymer composition according to any one of claims 1 to 5, wherein the PEG-grafted polyvinyl acetate copolymer has a degree of hydrolysis of 78.0 mol% to 88.7 mol%.

18. The polymer composition of claim 17, wherein the PEG-grafted polyvinyl acetate copolymer has a degree of hydrolysis of 80.0 mol% to 88.7 mol%.

19. The polymer composition according to any one of claims 1 to 5, wherein the PEG-grafted polyvinyl acetate copolymer has a degree of hydrolysis of 84.0 mol% to 98.0 mol%.

20. The polymer composition of claim 19, wherein the PEG-grafted polyvinyl acetate copolymer has a degree of hydrolysis of 93.0 mol% to 98.0 mol%.

21. The polymer composition according to any one of claims 1 to 5, wherein R a R b R c and R d Each is an aryl group that is independently substituted with one or more alkyl groups.

22. The polymer composition according to claim 21, wherein R a R b R c and R d Each is independently a phenyl group substituted with one or more butyl groups.

23. The polymer composition according to any one of claims 1 to 5, wherein the phosphite is selected from: bis(2,4-di-tert-butylphenol) pentaerythritol diphosphite, bis(2,4-di-tert-butyl-6-methylphenyl)-ethyl phosphite, bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, and tris(2,4-di-tert-butylphenyl) phosphite.

24. The polymer composition of claim 23, wherein the phosphite is tris(2,4-di-tert-butylphenyl) phosphite.

25. The polymer composition according to any one of claims 1 to 5, wherein the composition comprises vitamin E and epoxidized soybean oil.

26. The polymer composition according to any one of claims 1 to 5, wherein the amount of vitamin E contained in the composition is from 0.001% to 2% by weight.

27. The polymer composition according to any one of claims 1 to 5, wherein the composition comprises 0.001% to 5% by weight of epoxidized soybean oil.

28. The polymer composition according to any one of claims 1 to 5, wherein the vitamin E is in the form comprising a mixture of D-α-tocopherol and / or its esters and fatty acids.

29. The polymer composition of claim 28, wherein the D-α-tocopherol and / or its esters are present in the mixture in an amount of 0.1% to 0.75% by weight of the total weight of the mixture.

30. The polymer composition of claim 28, wherein the D-α-tocopherol and / or its esters are present in the mixture in an amount of 0.25% to 0.5% by weight of the total weight of the mixture.

31. The polymer composition of claim 28, wherein the mixture comprising D-α-tocopherol and / or its esters and fatty acids is obtained from a plant source.

32. The polymer composition according to any one of claims 1 to 5, wherein the vitamin E is synthetic vitamin E.

33. The polymer composition according to claim 32, wherein the synthetic vitamin E is DL-α-tocopherol and / or its ester.

34. The polymer composition according to any one of claims 1 to 5, wherein the polymer composition contains 0.1% to 10% by weight of water based on the total weight of the polymer composition.

35. The polymer composition of claim 34, wherein the polymer composition contains 0.4% to 0.6% water based on the total weight of the polymer composition.

36. The polymer composition according to any one of claims 1 to 5, wherein the composition is in the form of an extrusion.

37. The polymer composition according to any one of claims 1 to 5, wherein the composition is in the form of extruded filaments, powder, flakes or granules.

38. The polymer composition according to any one of claims 1 to 5, wherein the composition is in granular form.

39. The polymer composition of claim 38, wherein the diameter of the granules is 2 mm to 4 mm.

40. A thermally extrudable polymer composition, wherein in each case, based on the total weight of the polymer composition, it comprises: (a) 60% to 99% by weight of polymer (A), wherein polymer (A) is polyvinyl alcohol with a degree of hydrolysis of 66% to 79%, wherein the weight-average molecular weight (Mw) of polymer (A) is 26,000 to 87,000 and the number-average molecular weight (Mn) is 4,000 to 45,000. (b) 0.05% to 10% by weight of phosphites selected from the group consisting of formulas (V) and (VI): （V） (WE) Where R a R b R c and R d Each is an independent hydrocarbon group; (c) At least one additive selected from: (i) Vitamin E; and (ii) Epoxidized soybean oil; and (d) 0.01% to 10% by weight of PEG-grafted polyvinyl acetate copolymer, wherein the degree of hydrolysis of the polyvinyl acetate copolymer is 30 mol% to 98 mol%, the weight-average molecular weight (Mw) is 5,000 to 40,000, and the number-average molecular weight (Mn) is 1,000 to 20,000.

41. The polymer composition according to claim 40, wherein the polymer (A) is polyvinyl alcohol with a degree of hydrolysis of 70% to 74%.

42. The polymer composition according to claim 41, wherein the polymer (A) is polyvinyl alcohol with a degree of hydrolysis of 71.5% to 73.5%.

43. The polymer composition according to claim 40, wherein the polymer (A) is polyvinyl alcohol with a degree of hydrolysis of 75.0% to 79.0%.

44. The polymer composition according to claim 43, wherein the polymer (A) is polyvinyl alcohol with a degree of hydrolysis of 76.0% to 79.0%.

45. Use of the composition according to any one of the preceding claims in 3D printing.

46. ​​Use of the composition according to any one of claims 1 to 43 in fused deposition modeling.

47. Use of the composition according to any one of claims 1 to 43 in the manufacture of molten particles.

48. Use of the composition according to any one of claims 1 to 43 as a water-soluble carrier in 3D printing.

49. Use of the composition according to any one of claims 1 to 43 in water-soluble tools.

50. Use of the composition according to any one of claims 1 to 43 in packaging.

51. Use of the composition according to any one of claims 1 to 43 in a membrane.

52. Use of the composition according to any one of claims 1 to 43 in coatings.

53. A water-soluble carrier for 3D printing, comprising the composition according to any one of claims 1 to 43.

54. A method for preparing a composition according to any one of claims 1 to 43, the method comprising forming a premix of components (a) to (d) and extruding the premix through a die.

55. The method of claim 54, wherein the premix is ​​extruded from a twin-screw extruder having three melting zones.

56. The method of claim 55, wherein the temperature of the melting zone is independently 170°C to 220°C and / or the extrusion speed is 100 rpm to 200 rpm, and / or the feed rate is 0.1 mm / s. -1 Up to 1 mm s -1 And / or the diameter of the mold is 1 mm to 10 mm.

57. A method for preparing filaments, the method comprising extruding granules prepared according to the method of claim 54 from a single-screw extruder.

58. The method of claim 57, wherein the extruder has four melting zones, the temperature of which is independently between 170°C and 220°C and / or wherein the screw speed is between 3 rpm and 8 rpm.

59. The method of claim 57, wherein the filament is air-cooled.

60. The method of claim 54, wherein the extrudate is air-cooled.

61. A 3D printed article prepared from the composition according to any one of claims 1 to 43.

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