HK1209695B

HK1209695B - Selective sintering of structurally modified polymers

Info

Publication number: HK1209695B
Application number: HK15110622.8A
Authority: HK
Inventors: A．普菲策尔; F.米勒; M．罗伊特勒
Original assignee: Eos有限公司电镀光纤系统
Priority date: 2008-05-20
Filing date: 2015-10-28
Publication date: 2019-01-18

Description

Selective sintering of structurally modified polymers

The present application is a divisional application of an invention patent application with application number 200910159552.6 and invented name "selective sintering of structurally modified polymer" filed from chinese patent office on 5/19/2009.

Technical Field

The invention relates to a method for producing three-dimensional objects from a powder by a selective sintering method using electromagnetic radiation, wherein the powder comprises a polymer or copolymer. Furthermore, the invention relates to a three-dimensional object produced by the method, to an apparatus for producing a three-dimensional object by means of the method, and to the use of a preselected polymer powder in the method.

It is known, for example, from DE 4410046 that a method for producing three-dimensional objects by selective sintering using electromagnetic radiation can be carried out in a layered manner using an electromagnetic radiation source. In such a process, three-dimensional objects are produced in a laminar manner by applying layers of powder and bonding these layers to one another by selective solidification of the powder in positions corresponding to the cross-section of the object.

Description of the background Art

Fig. 1 shows, by way of example, a laser sintering apparatus with which a method for producing three-dimensional objects in a layered manner is carried out. As can be clearly seen in fig. 1, the device comprises a container 1. This container is open at the top and is bounded at the bottom by a support 4 for holding the object 3 to be formed. The work plane 6 is defined by the upper edge 2 of the container (or by the side walls of the container). The object is located on the top side of the support 4 and is formed from a plurality of layers of electromagnetic radiation curable build material in powder form, wherein the layers are parallel to the top side of the support 4. The support is thus movable in the vertical direction, i.e. parallel to the side walls of the container 1, via the height adjustment device. Thereupon, the position of the support 4 can be adjusted relative to the work plane 6.

Above the container 1 or more precisely above the work plane 6, an application device 10 is provided to apply the powder material 11 to be cured onto the support surface 5 or onto a previously cured layer. Furthermore, a radiation device in the form of a laser 7 emitting a directed beam 8 is arranged on the work plane 6. The light beam 8 is directed as a deflected light beam 8' towards the work plane 6 by a deflection device 9, such as a rotating mirror. The control unit 40 allows to control the support 4, the application device 10 and the deflection device 9. The components 1-6, 10, and 11 are located within the frame 100.

In the manufacture of the three-dimensional object 3, the powder material 11 is applied in layers to the support 4 or to previously solidified layers and solidified with the laser beam 8' in the respective powder layer at the position corresponding to the object. After each selective curing of the coating, the support is lowered by the thickness of the subsequently applied powder layer.

Many improvements in methods and apparatus for producing three-dimensional objects by selective sintering using electromagnetic radiation as compared to the systems described above exist and can also be used. For example, instead of using a laser and/or a beam, other systems that selectively output electromagnetic radiation can be used, such as mask exposure systems and the like.

However, in previous methods of selective sintering by electromagnetic radiation of polymer powders, no sufficient attention was given to the mechanical properties of the manufactured object.

Objects of the invention

It is therefore an object of the present invention to provide an improvement of a method for producing three-dimensional objects by selective sintering of polymer powders by electromagnetic radiation, which results in objects produced with improved mechanical properties.

Summary of the invention

The various aspects, advantageous features and preferred embodiments of the invention, each alone or in combination, summarized in the following items, are used to achieve the object of the invention:

(1) method for producing a three-dimensional object from a powder by a selective sintering process using electromagnetic radiation, wherein the powder comprises a polymer or copolymer having at least one of the following structural characteristics:

(i) at least one branching group in the backbone chain of the polymer or copolymer, with the proviso that when a Polyaryletherketone (PAEK) is used, the branching group is an aromatic building block in the backbone chain of the polymer or copolymer;

(ii) modification of at least one end group of the backbone chain of the polymer or copolymer;

(iii) at least one bulky group (bulk group) in the backbone chain of the polymer or copolymer, with the proviso that when a Polyaryletherketone (PAEK) is used, the bulky group is not selected from phenylene, biphenylene, naphthylene and CH₂-or an isopropylidene-linked aromatic hydrocarbon;

(iv) at least one aromatic group non-linearly connecting the backbone chains.

(2) The method according to item (1), wherein successive layers of the object that need to be formed from the curable powder material are subsequently cured in positions corresponding to the cross-section of the object.

(3) The method according to the item (1) or (2), in which the electromagnetic radiation is provided by a laser.

(4) A method according to any one of the preceding claims, comprising a predetermined and/or controlled cooling step after the sintering step.

(5)The method according to item (4), which comprises subjecting the object after completion of the object to a cooling rate of 0.01 to 10 ℃/min, preferably 0.1 to 5 ℃/min and more preferably 1 to 5 ℃/min from T of the polymer or copolymer contained in the powder_mCooling to a temperature lower by 1-50 ℃, preferably 1-30 ℃ and more preferably 1-10 ℃ to T of the polymer or copolymer contained in the powder_GA step of (1), wherein T_mIs the melting point and T of the polymer or copolymer contained in the powder_GIs the glass transition temperature of the polymer or copolymer.

(6) A method according to any of the preceding items, wherein the powder comprises a melting point T_mA polymer or copolymer in the range of from 100 ℃ to 450 ℃, preferably from 150 ℃ to 400 ℃ and more preferably from 250 ℃ to 400 ℃.

(7) A method according to any of the preceding items, wherein the powder comprises a glass transition temperature T_GA polymer or copolymer in the range of from 50 ℃ to 300 ℃, preferably from 100 ℃ to 300 ℃ and more preferably from 130 ℃ to 250 ℃.

(8) Process according to any one of the preceding items, in which the polymer or copolymer has a number average M of at least 10,000, more preferably of 15,000-200,000 and especially of 15,000-100,000_nOr a weight average M of at least 20,000, and more preferably 30,000-500,000_wAnd especially a weight average M of 30,000-200,000_w。

(9) A process according to any one of the preceding items, wherein the polymer or copolymer has a degree of polymerization n in the range of from 10 to 10,000, more preferably from 20 to 5000 and especially from 50 to 1000.

(10) A method according to any of the preceding items, wherein the polymer or copolymer contains at least one aromatic group in the backbone chain, preferably in the repeating units of the backbone chain.

(11) The method according to any one of the preceding items, wherein according to the improvement (iv), at least one non-linear linking aromatic group is comprised in a repeating unit of the backbone chain.

(12) The method according to item (11), wherein according to the improvement (iv), the non-linearly linked aromatic groups are independently selected from the group consisting of 1, 2-and 1, 3-phenylene, 1, 3-xylylene, 2,4 '-and 3, 4' -biphenylene, and 2, 3-and 2, 7-naphthylene.

(13) The method according to item (11) or (12), wherein according to the improvement (iv), the polymer or copolymer contains at least one additional, linearly linking aromatic group and/or at least one branching group different from the non-linearly linking aromatic group in the backbone chain, preferably in the repeating units of the backbone chain.

(14) A method according to any one of the preceding items, wherein the aromatic groups are each independently selected from unsubstituted or substituted mono-or polycyclic aromatic hydrocarbons.

(15) The method according to item (13) or (14), wherein according to the improvement (iv), the aromatic groups for linear linkage are each independently selected from the group consisting of 1, 4-phenylene, 4,4 ' -biphenylene, 4,4 ' -isopropylidenediphenylene, 4,4 ' -diphenylsulfone, 1,4-, 1,5-, 2, 6-naphthylene, 4,4 ″ -p-terphenylene (terphenylene) and 2, 2-bis- (4-phenylene) -propane.

(16) The process according to any one of the preceding items, wherein according to the improvement (i) the branching group is an aliphatic, aromatic or heteroaromatic hydrocarbon having at least one substituent or one side chain, and in the case of the use of Polyaryletherketones (PAEK) the branching group is an aromatic structural unit in the backbone chain of the polymer or copolymer.

(17) The method according to item (16), wherein according to the improvement (i), the side chains are each independently selected from C₁-C₆Unbranched or branched, chain-or cyclic alkyl or alkoxy radicals and aryl radicals.

(18) The process according to item (16) or (17), wherein according to the improvement (i) the side chains are each independently selected from methyl, isopropyl, tert-butyl or phenyl.

(19) A process according to any one of the preceding items, wherein according to the improvement (ii) the terminal group of the backbone chain is modified with a terminal alkyl, alkoxy, ester and/or aryl group.

(20) A process according to any one of the preceding items, wherein according to improvement (iii) the bulky group is an aromatic or non-aromatic group and, in the case of the use of a Polyaryletherketone (PAEK), is not selected from phenylene, biphenylene, naphthylene and CH₂-or an isopropylidene-linked aromatic hydrocarbon.

(21) The method according to item (20), wherein according to improvement (iii), the bulky group is a polycyclic aromatic or non-aromatic group.

(22) The method according to item (20) or (21), wherein according to the improvement (iii), the bulky group is selected from phenylene, naphthalene, anthracene, biphenyl, fluorene, terphenyl, decahydronaphthalene or norbornane.

(23) A method according to any of the preceding items, wherein a mixture of at least two different polymers or copolymers is used, wherein at least one of the (co) polymer components has at least one of the structural characteristics mentioned in item 1.

(24) A process according to any of the preceding items, wherein the polymer or copolymer is formed on the basis of a Polyamide (PA), a Polyaryletherketone (PAEK), a Polyarylethersulfone (PAES), a polyester, a polyether, a polyolefin, a polystyrene, a polyphenylene sulfide, a polyvinylidene fluoride, a polyphenylene oxide, a polyimide or a block copolymer comprising at least one of the aforementioned polymers.

(25) A process according to any of the preceding items, wherein the polymer or copolymer is formed on the basis of a Polyamide (PA), a Polyaryletherketone (PAEK), a Polyarylethersulfone (PAES) or a block copolymer comprising at least one of the aforementioned polymers.

(26) The process according to item (24) or (25), wherein the block copolymer is preferably a Polyaryletherketone (PAEK)/Polyarylethersulfone (PAES) -diblock copolymer or a PAEK/PAES/PAEK-triblock copolymer.

(27) The method according to any of the preceding items, wherein the polymer is a Polyaryletherketone (PAEK) formed on the basis of Polyetheretherketone (PEEK), Polyetherketoneketone (PEKK), Polyetherketone (PEK), Polyetheretherketoneketone (PEEKK), Polyetheretherketone (PEEEK) or a copolymer comprising at least one of the above polymers.

(28) The process according to item (27), wherein the Polyaryletherketone (PAEK) is formed on the basis of a Polyetherketoneketone (PEKK) polymer or copolymer.

(29) A process according to any one of the preceding items, wherein the polymer or copolymer based on Polyaryletherketones (PAEK) has a density of 0.05-1.0kN s/m²Preferably 0.15-0.6kN s/m²And especially 0.2-0.45kN s/m²The melt viscosity of (2).

(30) The process according to any of items (24) to (29), wherein the Polyaryletherketone (PAEK) polymer or copolymer has a degree of polymerization n of preferably 10 to 1,000, more preferably 20 to 500, and especially 40 to 250.

(31) The method according to any one of items (27) to (30), wherein the Polyetherketoneketone (PEKK) polymer or copolymer comprises, in the backbone chain of the polymer, preferably in the repeating units of the backbone chain, 1, 4-phenylene as the linear-linking aromatic group and 1, 3-phenylene as the nonlinear-linking aromatic group.

(32) The method according to any one of items (27) to (31), wherein the ratio of repeating units each comprising at least one 1, 4-phenylene unit to repeating units each comprising one 1, 3-phenylene unit is 90/10 to 10/90, preferably 70/30 to 10/90, more preferably 60/40 to 10/90.

(33) Three-dimensional object obtained by selective sintering of a polymer, copolymer or polymer blend in powder form using electromagnetic radiation, wherein the polymer or copolymer used for the powder has at least one of the following structural characteristics:

(iii) at least one bulky group in the backbone chain of the polymer or copolymer, with the proviso that when a Polyaryletherketone (PAEK) is used, the bulky group is not selected from phenylene, biphenylene, naphthylene and CH₂-or an isopropylidene-linked aromatic hydrocarbon;

(iv) at least one aromatic group non-linearly connecting the backbone chains.

(34) The three-dimensional object according to item (33), wherein the polymer or copolymer is as defined in items 6 to 32.

(35) Apparatus for manufacturing a three-dimensional object from a powder by selective sintering using electromagnetic radiation of the powder, wherein the apparatus comprises a temperature control device arranged to set a predetermined cooling operation of the object after manufacture of the object.

(36) The apparatus according to item (35), wherein the cooling rate set by the temperature control device depends on the type of polymer, copolymer or polymer blend contained in the powder.

(37) The apparatus according to item (35) or (36), wherein the temperature control device is set according to a predetermined type of the polymer, copolymer or polymer blend.

(38) A manufacturing system, comprising: the device according to any one of items (35) to (37), and the powder comprising at least one polymer or copolymer as defined in items (6) to (32).

(39) Use of a polymer powder in a process for the manufacture of a three-dimensional object by means of selective electromagnetic radiation sintering, wherein the polymer is preselected from the group consisting of polymers or copolymers having at least one of the following structural characteristics:

(iv) at least one aromatic group non-linearly connecting the backbone chains.

(40) The use according to item (39), wherein the polymer or copolymer is as defined in items (6) to (32).

It has surprisingly been found that when using structurally specifically modified polymers or copolymers in a selective sintering process, a significant improvement of certain very advantageous mechanical properties is obtained in the manufactured three-dimensional object, including but not limited to high stiffness, high compressive strength, high impact strength, high maximum tensile and flexural strength as well as high elongation at break and high heat deflection temperature, while on the other hand the opposite properties, such as good chemical resistance and low post-crystallization, are still well balanced. Furthermore, it has surprisingly been found that the above-mentioned large improvements in mechanical properties and a good balance with the contrary properties are ensured by the particular process conditions or by observing the cooling rate after sintering, respectively. In addition, a significantly improved combination of both the crystallinity and the low porosity, which are appropriately set in the manufactured three-dimensional object, can be achieved, which contributes to further improvement of the above-described properties. The advantages of the invention are particularly achieved when modified polyaryletherketone polymers or polyaryletherketone copolymers or polyamide polymers or polyamide copolymers, respectively, are used as polymer material for the polymer powder. The ideal combination of the various characteristics achieved by the present invention is mainly due to the fact that: the structurally specific modified polymers and copolymers allow the setting of an advantageous range of crystallinity in the three-dimensional object produced and at the same time a low porosity of the three-dimensional object. Furthermore, the advantages of the present invention may also be applied to composite materials, wherein the crystallinity value is related to the polymer matrix of the composite material. Such composites comprise, in addition to a matrix comprising the respective polymer, copolymer or polymer blend, one or more fillers and/or additives.

For polymers in general, the final crystallinity in the resulting body is 80% or less, preferably 50% or less, more preferably 5 to 70%, even more preferably 15 to 50% and especially 15 to 35%. Especially for e.g. Polyaryletherketones (PAEKs), the final crystallinity in the obtained object is 5-45%, preferably 10-40%, more preferably 15-35%, even more preferably 15-30%, and especially 20-25%. Especially for e.g. Polyamides (PA), the final crystallinity in the obtained object is 10-50%, preferably 15-40%, more preferably 15-35% and especially 20-30%. The porosity of the polymer is generally less than 10%, preferably less than 5%, more preferably less than 3% and especially less than 2%.

As a preferred alternative to conventional polymer processing techniques involving pressure processing of polymers, like for example injection molding, the process according to the invention can be carried out in a layer-wise manner in an additive process, wherein successive layers of the object, which are required to be formed from the curable powder material, are subsequently cured by electromagnetic radiation at locations corresponding to the cross-section of the object.

Brief description of the drawings

Fig. 1 schematically shows a laser sintering apparatus for the layered production of three-dimensional objects.

Description of the preferred embodiments

The invention will now be described in more detail with reference to further preferred and more advantageous embodiments and examples, which however are given for illustrative purposes only and should not be construed as limiting the scope of the invention.

When the polymeric powder material comprises a polymer or copolymer having at least one condition selected from the following, optionally a combination of these conditions: (i) at least one branching group in the backbone chain, (ii) modification of the end groups, (iii) at least one bulky group and (iv) at least one aromatic group non-linearly connecting the backbone chain, can lead to a significant improvement of certain very advantageous mechanical properties, including high stiffness, high compressive strength, high impact strength, high maximum tensile and flexural strength and high elongation at break and high heat distortion, while on the other hand the opposite properties, such as good chemical resistance and low post-shrinkage due to post-crystallization, are still well balanced. Furthermore, a reduction of the porosity of the manufactured object is additionally made possible by an improvement of the mechanical properties of the manufactured object.

Objects made by selective sintering processes using electromagnetic radiation of a powder comprising at least one polymer typically have a crystallinity value that is much higher than the crystallinity of objects made by conventional polymer processing techniques like, for example, injection molding processes, i.e. in processes for making three-dimensional objects from powders by selective sintering processes using electromagnetic radiation of a powder comprising at least one polymer, such as the type of process shown in fig. 1, the crystallinity of the manufactured objects tends to become higher if the structurally modified polymer or copolymer of the invention is not used. Specifically, in the method of layer-wise structuring, the melting point T of the polymer is generally used_mA high powder bed temperature of about 1-50 deg.C, preferably 1-30 deg.C, even more preferably 1-20 deg.C and most preferably 1-10 deg.C lower. The object is typically exposed to the higher processing temperatures for a considerable time and often undergoes a very long cooling time. In order to prevent or minimize curling of the object during construction, the processing temperature should be kept close to the melting point of the polymer contained in the powder, in order to ensure good connection between the successive layers and to minimize the occurrence of undesired melting of the powder particlesAnd (4) forming pores. Thus, the temperature of the powder bed remains above the crystallization temperature Tc of the polymer throughout the build process. The formed object itself may be exposed to temperatures above Tc for extended periods of time. At the end of the build process, when all the heating sources of the sintering machine are turned off, a cooling process of the object through Tc is started due to natural heat losses of the environment. This may take hours to days due to the low thermal conductivity of the polymer powder and the large powder bed, depending on the polymer powder used and the processing conditions, i.e. without predetermining a suitable cooling rate, which may further enhance the crystallization of the final polymer body during cooling. Without proper control, even post-crystallization of laser sintered polymer objects can occur. Thus, without the controlled cooling step according to the invention, a high and partly extremely high crystallinity is obtained in the manufactured object. Furthermore, without properly limiting the crystallinity, the relevant mechanical properties of the object may be compromised.

On the other hand, in the selective sintering method according to the invention, the crystallinity in the manufactured object may advantageously be adjusted to be still sufficiently high, while ensuring a positive influence of high chemical resistance, low post shrinkage at temperatures above Tg, or high stiffness for the manufactured object. Thus, an excellent balance of properties can be achieved by the present invention.

When the crystallinity of the material made from the polymer powder material is suitably limited and preferably adjusted within a specific range, significant improvements in certain very advantageous mechanical properties like tensile strength, young's modulus and elongation at break can be achieved. Particularly effective and preferred measures to limit the crystallinity of the manufactured object are: 1) preselecting a suitable type of polymer material, 2) taking care to preselect the structural properties and/or modifications of the polymer comprised by the powder, and/or 3) taking care of a predetermined and/or controlled cooling step after the end of the sintering process of the object.

Thus, according to a preferred embodiment of the invention, the predetermined and/or controlled cooling step is preferably applied to the object after completion of the object after sintering. The predetermined and/or controlled cooling step may be achieved by a predetermined slow cooling, possibly slower than natural (passive) cooling, or by active cooling in order to provide a fast cooling. Since the conditions of the predetermined and/or controlled cooling step depend mainly on the type and specifications of the polymer, copolymer or polymer blend used, the useful set conditions of the cooling step can be tested experimentally, provided that the final crystallinity in the manufactured object is controlled such that the manufactured object has the desired mechanical properties.

However, the cooling rate after finishing of the object also affects the curling of the object and thus the dimensional stability of the object. It has surprisingly been found that the cooling rate can be predetermined such that the three-dimensional object not only has a reduced crystallinity in order to provide the advantageous mechanical properties described above, but also has a high dimensional stability, i.e. it does not curl.

Suitable types of polymeric materials can be selected from: polyaryletherketones (PAEK), Polyarylethersulfones (PAES), polyamides, polyesters, polyethers, polyolefins, polystyrene, polyphenylene sulfide, polyvinylidene fluoride, polyphenylene oxides, polyimides and copolymers comprising at least one of the foregoing polymers, wherein the choice is not, however, limited to the foregoing polymers and copolymers. For example, suitable PAEK polymers and copolymers are preferably selected from: polyetheretherketone (PEEK), Polyetherketoneketone (PEKK), Polyetherketone (PEK), Polyetheretherketoneketone (PEEKK), Polyetherketoneetherketoneketone (PEKEKK), Polyaryletheretherketone (PEEEK) and copolymers comprising at least one of the foregoing polymers. Suitable polyamide polymers or copolymers can be selected from the group consisting of polyamide PA6T/6I, poly-m-xylylene adipamide (PA MXD6), polyamide 6/6T, polyamide elastomers like polyether-block-amides such as PEBAX^T _mA type material, polyamide 6, polyamide 66, polyamide 11, polyamide 12, polyamide 612, polyamide 610, polyamide 1010, polyamide 1212, polyamide PA6T/66, PA4T/46 and copolymers comprising at least one of the foregoing polymers. Is suitably aThe polyester polymer or copolymer can be selected from the group consisting of polyalkylene terephthalates (e.g., PET, PBT) and their copolymers with isophthalic acid and/or 1, 4-cyclohexanedimethanol. Suitable polyolefin polymers or copolymers can be selected from the group consisting of polyethylene and polypropylene. Suitable polystyrene polymers or copolymers can be selected from the group consisting of syndiotactic and isotactic polystyrenes. The respective structural characteristics defined in the appended claims can be taken into account depending on the suitable method and manner, the structural change, the choice of suitable components of the (co) polymers, etc.

Particularly preferred polymers or copolymers for use in the selective sintering process according to the invention have at least one of the following structural characteristics and/or modifications:

(iv) at least one aromatic group non-linearly connecting the backbone chains.

The structural modifications (i) to (iv) are explained below.

With respect to the structural characteristic (i) "branching group", the group G is understood to mean, in addition to the bonds shown below which connect the various parts of the backbone chain of the polymer (parts a and B of the backbone chain),

also having at least one side chain and a substituent S (respectively). Advantageously, G is an aliphatic hydrocarbon, an aromatic hydrocarbon or a heteroaromatic hydrocarbon. This side chain or substituent "S" individually affects the mobility of the polymer chain in the melt and can therefore suitably affect the final crystallinity of the manufactured object. Preferably, the substituents are each independently selected from the group consisting of C₁-C₆Unbranched or branched, linear or cyclic alkyl or alkoxy radicals and aryl radicals, methyl, isopropyl, tert-butyl or phenyl being particularly preferred. Furthermore, side chains or substituents S are preferred, each of which allows further derivatization-optionally after deprotection-of the polymers or copolymers obtained, for example the synthesis of graft copolymers. The above exemplary illustration of a branching group shows only one branching group. However, there may be more branching groups present in the polymer, particularly when the branching groups are part of the repeat units of the polymer. The structural units (G-S) can also be a single or multiple component of the A and/or B part of the backbone chain shown above. When Polyaryletherketones (PAEKs) are used, the branching groups are aromatic structural units in the backbone chain of the polymer or copolymer;

with respect to the structural characteristics (ii) "modification of at least one of the end groups of the polymer or copolymer skeleton chain" it is intended that one or both of the ends X and Y of the polymer skeleton chain pass through the end group R, as indicated below₁And/or R₂The derivatization of (a) is carried out,

(X)_nbackbone chain of Polymer- (Y)_m→(R₁)_nBackbone chain of Polymer- (R)₂)_m

Wherein n, m are each independently 0 or an integer, preferably 1, wherein n, m are not both 0 at the same time. There are also various modifications of the end groups, as denoted by n, m. It is relevant in this embodiment that the respective unmodified terminal groups X and Y can act as seed crystals and thus stimulate undesirable over-crystallization. Thus, at least one of the terminal groups X and Y of the polymer or copolymer can be derivatized in order to interfere with the crystallization and in order to reduce the crystallizationThis approach limits the crystallinity of the fabricated object. Preferably, the terminal group R₁And R₂Independently selected from alkyl, alkoxy, ester group and/or aryl. For example, R₁And R₂Each independently selected from the group consisting of branched and unbranched C₁-C₆Alkyl, preferably methyl, isopropyl or tert-butyl; branched or unbranched C₁-C₆Alkoxy, preferably methoxy, isopropoxy, tert-butoxy; substituted or unsubstituted C₁-C₆Aliphatic ester groups, preferably methyl, ethyl, isopropyl or tert-butyl ester; substituted or unsubstituted aromatic ester groups, preferably benzoate groups, and substituted or unsubstituted aryl groups, preferably phenyl, naphthyl, anthracenyl. The end groups may also be chosen such that they are preferably higher than the polymer T_mBy chemical reaction with each other, leading to chain extension, for example polycondensation reactions, electrophilic or nucleophilic substitution reactions, or coupling reactions. This in turn leads to a reduction in the final crystallinity within the object due to the increased molar mass.

By structural feature (iii) "bulky group" is meant, for example, cycloalkyl groups like cyclohexyl or polycyclic cycloalkyl groups like decalin or norbornane, which may contain heteroatoms within their ring structure. Further examples of bulky groups are aromatic hydrocarbons like phenylene or fused polycyclic aromatic or heteroaromatic hydrocarbons, for example (residues of) naphthalene or anthracene, (residues of) fluorene and fluorene derivatives, or polynuclear aromatic hydrocarbons like biphenylene or biphenylene. The bulky groups represent rigid rod-shaped segments within the polymer chain and can therefore interfere with crystallization and result in lower final crystallinity in the fabricated object. The choice of bulky group depends on the type of polymer or copolymer. Although one phenylene unit may already represent a bulky group, for example in the case of aliphatic polymers such as polyethylene, phenylene is not considered a bulky group in the case of polyaryletherketones containing phenylene units by definition. In the case of Polyaryletherketones (PAEK), for embodiments according to structural feature (iii), the bulky group is not selected from the group consisting of phenylene, biphenylene, naphthylene, and CH₂-or IsoyaPropyl-linked aromatic hydrocarbons.

With structural property (iv) "non-linearly linking aromatic group", aromatic group means that it links the parts of the backbone chain such that the parts are non-linearly positioned with respect to each other, i.e. the angle between the parts of the backbone chain is different from 180 °.

As for the introduction of aromatic groups for nonlinear linking in the backbone chain of the polymer, the final crystallinity in the manufactured object can be reduced in a controlled manner, whereby favorable mechanical properties like young's modulus, tensile strength and elongation at break can be obtained. In addition, the melting point of the polymer can be lowered by the introduction of aromatic groups for nonlinear connection, so that it is in a particularly favorable temperature range, and the glass transition temperature can be set so that the object produced has a particularly favorable heat distortion temperature.

Aromatic groups for non-linear attachment are, for example, 1, 3-phenylene and 1, 2-phenylene, since they link the A and B moieties of the polymer backbone chain together at angles of 120 and 60, respectively, as shown below:

other preferred non-linear aromatic radicals are, for example, 1, 3-xylylene, 2,4 'and 3, 4' -biphenylene and 2, 3-and 2, 7-naphthylene.

In contrast to non-linear linking groups, aromatic groups for linear linking join the various portions of the backbone chain at an angle of 180 °. For example, 1, 4-phenylene represents an aromatic group for linear attachment, since the a and B portions of the polymer backbone chain, depicted schematically, are attached at an angle of 180 °, as shown below.

The groups for linear attachment consisting of fused aromatic groups can linearly attach various portions of the backbone chain in two different ways, which is exemplified by naphthalene, but are also suitable for other fused ring aromatic hydrocarbons such as anthracene or phenanthrene. For example, naphthalene in the form of 1, 4-naphthalene can connect the A and B portions of the polymer backbone chain at an angle of 180. Alternatively, naphthalene can also be connected linearly in the form of 1, 5-naphthylene or 2, 6-naphthylene, where the A and B parts of the skeleton chain depicted in a schematic manner are arranged parallel to one another.

1, 5-naphthylene group as a linear linking unit:

2, 6-naphthylene group as a linear linking unit:

the above exemplary figures for the respective non-linear linking and linear linking aromatic groups show only one respective non-linear and linear linking aromatic group. However, more groups, each of which is non-linearly and linearly linking, may be present in the polymer, especially if the non-linearly or linearly linking groups are components of the repeating units of the polymer.

Depending on the structural properties (iv), a combination of non-linearly linking aromatic groups and linearly linking aromatic groups is possible.

Furthermore, a suitably set molecular weight of the polymer contained in the powder can cause a significant decrease in the crystallinity in the manufactured object, which in turn can cause a significant decrease in the crystallinity of the manufactured objectResulting in a significant improvement of certain very advantageous mechanical properties in the manufactured object. Thus, molecular weight M_n(average value) is preferably set to at least 10,000, more preferably to at least 15,000-200,000 and especially to at least 15,000-100,000, or M_wThe (average value) is preferably set to at least 20,000, and more preferably 30,000-500,000, and particularly 30,000-200,000.

Similar explanations as described above for molecular weight apply to the melt viscosity of the polymer or copolymer. The melt viscosity related to the molecular weight of the polymer or copolymer is as follows: the higher the molecular weight of the polymer or copolymer, the higher its melt viscosity. Thus, for example, the preferred melt viscosity of the generic polyaryletherketones and their copolymers is in the range of 0.05 to 1.0kN s/m²Preferably 0.15-0.6kN s/m²And especially 0.2-0.45kN s/m²Within the range. Melt viscosity can be measured according to the teaching of US patent 2006/0251878A1 in a capillary viscometer at 400 ℃ and 1000s^-1Is measured at a shear rate of (2).

The polymers or copolymers can be blended with the alloy-forming components in a mixture (blend), wherein a blend of at least two different polymers or copolymers is used. In such blends, it is preferred that at least one component of the blend reduces the final crystallinity of the manufactured object.

For the desired result, in particular the crystallinity in the manufactured object and its mechanical properties, beyond the general conditions of the structural characteristics (i) and (iii) included in the polymer or copolymer, there are the following limits for the Polyaryletherketones (PAEKs):

for feature (i): the branching group is an aromatic structural unit in the backbone chain of the polymer or copolymer, and

for feature (iii): the bulky group not being selected from the group consisting of phenylene, biphenylene, naphthylene and CH₂-or isopropylidene-linked aromatic hydrocarbons.

For other types of polymers, in particular Polyamides (PA), polyesters, polyethers, polyolefins, polystyrenes, polyphenylene sulfides, polyvinylidene fluorides, polyphenylene ethers, polyimides or copolymers comprising at least one of the abovementioned polymers, the restrictions given for polyaryletherketones do not apply.

In the following, some important structural properties or modifications of the polymer or copolymer material are exemplified by PAEK polymers and copolymers suitable for a pre-selection suitable for a selective sintering process using electromagnetic radiation. It will be apparent to those skilled in the art that the structural properties or modifications described below can be equally applied to other types of polymers or copolymers.

The general structure of PAEK or PAES polymers and copolymers preferred for the manufacture of laser sintered objects is shown in the general formula given below, where the preferred structural uniqueness, alone or in combination, in order to obtain low crystallinity is further described below:

Ar₁、Ar₂and Ar₃Is an unsubstituted or substituted mono-or polycyclic aromatic hydrocarbon, linked linearly or non-linearly, with Rf₁、Rf₂And/or Rf₃Independently for H, the substituents can be optionally selected from:

Rf₁、Rf₂、Rf₃each independently selected from C₁-C₆Straight-chain, branched or cyclic alkyl and alkoxy groups, and aryl groups, preferably Me, i-Pr, t-Bu, Ph (for unsubstituted Ar)₁、Ar₂And Ar₃，Rf₁、Rf₂、Rf₃H), wherein each Ar₁，Ar₂And Ar₃May each have one or more substituents Rf₁、Rf₂、Rf₃，

X ═ O and/or S

Y ═ CO and/or SO₂

Z＝SO₂CO, O and/or S

a is a lower integer greater than 0, preferably lower than 12, more preferably from 1 to 6 and especially from 1 to 3,

b is a lower integer greater than 0, and preferably lower than 12, more preferably from 1 to 6 and especially from 1 to 3,

c is 0 or a lower integer, preferably less than 12, more preferably from 1 to 6 and especially from 1 to 3,

n represents the degree of polymerization.

In the above formulae, the indices a, b and c each represent the number of the respective units in the repeating units of the polymer or in the repeating units of the copolymer, wherein one or more units of the same type, for example the unit represented by index a, can be located between units of different types, for example the units represented by indices b and/or c. The position of the respective unit in the repeating unit can be derived from the abbreviations of the PAEK derivatives.

The above general formula of PAEK or PAES polymers or copolymers will be clearly explained by means of the following examples of PAEK polymers according to the invention. Thus, in one embodiment using a PAEK according to the invention, Ar₁Is unsubstituted 4, 4' -p-biphenylene, X ═ O and a ═ 1, Ar₂Is unsubstituted 1, 4-phenylene, Y is O and b ═ 1 and Ar₃Is unsubstituted 1, 4-phenylene, Z is CO and c ═ 1, wherein the following structural formula represents this PAEK

Wherein n represents the degree of polymerization.

In addition to the conventional 1,4 phenylene group, a bulkier group such as one selected from the group consisting of biphenylene, naphthylene, and CH in the PAEK polymers or copolymers₂-or isopropylidene-linked aromatic hydrocarbons should be selected,such as p-biphenylene.

The following two examples of PAEK polymers, PEKK and PEKEKK, are examples of PAEK polymers having aromatic groups for linear attachment. Thus, for example, for PEKK, Ar₁Is unsubstituted 1, 4-phenylene, X is O and a is 1, Ar₂Is unsubstituted 1, 4-phenylene, Y is CO and b ═ 2 and c ═ 0, where the following structural formula represents PEKK

Wherein n represents the degree of polymerization. In another example, PEKEKK, Ar₁Is unsubstituted 1, 4-phenylene, X is O and a ═ 2, Ar₂Is unsubstituted 1, 4-phenylene, Y is CO and b ═ 3 and c ═ 0, where the following structural formula denotes PEKEKK

Wherein n represents the degree of polymerization.

The following examples show PAEK polymers, i.e. PEKK copolymers with units for nonlinear linking, used according to the invention. This PEKK copolymer has 2 different repeating units (see repeating units a and B in the following structural formula).

Repeating unit A:

repeating unit B:

in the repeating unit A, Ar₁Is not coveredSubstituted 1, 4-phenylene, X is O and a is 1, Ar₂Is unsubstituted 1, 4-phenylene, Y is CO, b ═ 2 and c ═ 0. In the repeating unit B, Ar₁Is unsubstituted 1, 4-phenylene, X is O and a is 1, Ar₂Is unsubstituted 1, 3-phenylene, Y is CO and b ═ 1 and Ar₃Is 1, 4-phenylene, Z is CO and c is 1. Depending on the synthesis, the repeating units a and B may be arranged strictly alternately, randomly or in blocks in the backbone chain of the copolymer. The degree of polymerization n of this PEKK copolymer represents n₁And n₂The sum of (a) and (b).

In the selective sintering of the above-described PEKK copolymers it was surprisingly found that the lower the final crystallinity of the object produced, the higher the content of 1, 3-phenylene units (compare example 1 with example 2). It has furthermore been found that the melting point of the copolymers can be lowered by increasing the content of 1, 3-phenylene units in the PEKK copolymer. This reduction in melting point is an advantage for the process in laser sintering. Thus, a lower temperature of the process chamber can be selected, which allows for an energy efficient sintering process. Thus, the 1, 4-phenylene unit Ar in the repeating unit A₂With 1, 3-phenylene units Ar in the repeating unit B₂The ratio of (A) is preferably 90/10-10/90, more preferably 70/30-10/90 and especially 60/40-10/90. Such PEKK copolymers can be obtained, for example, by electrophilic aromatic substitution of diphenyl ether with terephthalic acid and terephthaloyl chloride (respectively) as monomers having 1, 4-phenylene units and isophthalic acid and isophthaloyl chloride (respectively) as monomers having 1, 3-phenylene units.

In addition, the ratio between the number of ketone groups Y and the number of ether groups or thioether groups is preferably from 1:4 to 4: 1. In this range, the final crystallinity in the manufactured object can be significantly reduced.

Aromatic hydrocarbon Ar₁、Ar₂And Ar₃The larger the required space, the more the aromatic hydrocarbon behaves like a rigid rod-shaped segment and the lower the final crystallinity of the object produced. It is therefore preferred that, for the aromatic group for linear attachment, the aromatic hydrocarbon group Ar₁、Ar₂And Ar₃Independently selected from the group consisting of 1, 4-phenylene, 4,4 '-biphenylene, 4, 4' -isopropylidenediphenylene, 4,4 '-diphenylsulfone, 1,4-, 1, 5-and 2, 6-naphthylene, 4, 4' -p-biphenylene and 2, 2-bis- (4-phenylene) -propane, and for the non-linearly linking aromatic groups, independently selected from the group consisting of 1, 2-and 1, 3-phenylene, 1, 3-xylylene, 2,4 '-and 3, 4' -biphenylene and 2, 3-and 2, 7-naphthylene.

In the case of polyaryletherketones, the branching group can be substituted with Rf₁、Rf₂、Rf₃Aromatic hydrocarbon Ar of₁、Ar₂And Ar₃Provided that in this case it is independent of whether the linkage on the aromatic hydrocarbon is linear or non-linear.

Another possibility to tailor the polymer such that low crystallinity in the manufactured object is achieved after the selective sintering process is the use of a suitable copolymer. For PAEK, in addition to the above-mentioned PEKK copolymer, its copolymer with a Polyarylethersulfone (PAES) is preferred, and especially preferred is a Polyaryletherketone (PAEK)/Polyarylethersulfone (PAES) -diblock copolymer or a PAEK/PAES/PAEK-triblock copolymer, more preferred is a Polyetherketone (PEK)/Polyethersulfone (PES) -diblock copolymer or a PEK/PES/PEK-triblock copolymer. It has been found that the lower the crystallinity of the manufactured object, the higher the amount of the polyarylethersulfone component. Therefore, the ratio of the number of sulfone groups Z to the number of ketone groups Y is preferably between 50:50 and 10: 90. Within this ratio range, the glass transition temperature (Tg) and melting point (T) of the polymeric material_m) Can be adjusted so as to be suitable for processing polymers in an apparatus for manufacturing three-dimensional objects by selective sintering using electromagnetic radiation. In order to provide suitable processing temperatures for the selective sintering process, the PEK/PES copolymer preferably has a Tg of greater than 180 ℃ and a melting temperature T of 300-430 ℃_m。

The end groups of the backbone chains of the polymer or copolymer depend on the type of monomers used for the synthesis and on the type of polymerization reaction. In the following, two different types of PAEK synthesis routes are shown, resulting in different types of PAEKs with different end groups.

PAEKs can be synthesized in two general ways, namely by electrophilic aromatic substitution (friedel-crafts-acylation) or nucleophilic aromatic substitution. For example, in the nucleophilic synthesis of PAEK, 1, 4-bishydroxybenzene is polymerized with a4, 4' -dihalogenobenzophenone component:

xHO-Ph-OH+(y+1)Hal-Ph-CO-Ph-Hal→

Hal-Ph-CO-Ph-[O-Ph-O]x[Ph-CO-Ph]y-Hal，

where Hal is F, Cl, Br and x and y represent the number of monomers introduced into the polymer.

As a result, the PAEK backbone chain in the PEEK example above may, either not at either end of the backbone chain or at one (not shown) or both (shown) ends of the backbone chain, be terminated by residual halogen groups after polymerization, most suitably by fluorine, optionally chlorine or bromine as an option. The same applies to the synthesis of PAEK or Polyethersulfone (PAES) copolymers in which the dihalogenated ketone units may be partially replaced by dihalogenated aromatic sulfones. The aromatic dihydroxy component can likewise be partially or completely replaced by a dithiol component.

For example, the halogen-substituted end of the polymer can be derivatized by a termination reaction with phenol:

2Ph-OH+Hal-Ph-CO-Ph-[O-Ph-O]x[Ph-CO-Ph]y-Hal→

Ph-O-Ph-CO-Ph-[O-Ph-O]x[Ph-CO-Ph]y-O-Ph

preferably, Hal in the above formula is F.

The same applies to the synthesis of PAEK-or Polyethersulfone (PAES) copolymers in which the dihalogenated ketone units are partially replaced by dihalogenated aromatic sulfone units. The aromatic dihydroxy component can likewise be partially or completely replaced by a dithiol component.

In the case of the synthesis of PAEK polymers or copolymers by electrophilic aromatic substitution, diacyl aromatic hydrocarbons (diacrylamides), such as aromatic diacids or preferably aromatic diacid chlorides or aromatic dianhydrides, are polymerized with a bis-aromatic ether or thioether component. For example, for PEKK, this may result in PEKK polymers or copolymers having phenyl groups not on either end of the backbone chain or on one (not shown) or both (shown) ends of the backbone chain:

xR_AOC-Ph-COR_A+(y+1)Ph-O-Ph→

Ph-O-Ph-[OC-Ph-CO]x[Ph-O-Ph]y-H，

wherein R is_AIs Cl or-OH and x and y represent the number of monomers introduced into the polymer.

Alternatively, synthetic methods via a single monomer route using, for example, aromatic monoacids can be employed.

For example, the phenyl group at the end of the polymer can be derivatized by a termination reaction with benzoyl chloride:

2Ph-COCl+Ph-O-Ph-[OC-Ph-CO]x[Ph-O-Ph]y-H→

Ph-CO-Ph-O-Ph-[OC-Ph-CO]x[Ph-O-Ph]y-OC-Ph

regardless of the choice of nucleophilic or aromatic substitution reaction, the end groups preferably may be substituted in order to slow the crystallization of the polymer, for example such that the PAEK polymer has the general formula:

r_t-u-[paek]-u-r_t，

wherein U is a linking moiety, e.g. NH, O, CO, CO-O-, SO, a single bond, - (CH)₂)_kWherein k is 1-6, etc.; and left-hand and right-hand structural parts R_TMay be identical or different structural groups, usually the structural moiety R_TAre the same.

Preferably, R_TSelected from unsubstituted or substituted aliphatic or aromatic hydrocarbon residues. U may be reacted with a polymer orDirect reaction of the ends of the copolymer to form, for example, a monofunctional hydroxy compound may form O as U, or it may be introduced as a substituent of a terminating reagent, for example, HO-Ph-COO-tert-butyl may form COO as U.

Furthermore, if it is desired to increase the crystallization rate in order to suitably adjust the crystallinity of the three-dimensional object produced, the polyaryletherketones having halogenated end groups can be end-capped with ionic groups, such as, for example, phenolates, for example NaOPhSO₃Na or NaOPhCPhOPhSO₃And (5) stopping by Na. Subsequent acidification of the phenate with, for example, HCl results in the formation of-SO₃H end groups, which show a slightly reduced nucleation (nucleation) effect.

Furthermore, in the following-again exemplified-now exemplified with PA polymers and copolymers-other important structural properties or modifications of the polymer or copolymer materials are described, which are suitable for a pre-selection which is suitable for a selective sintering process using electromagnetic radiation. It will be apparent to those skilled in the art that the structural features or modifications described below can be equally applied to other types of polymers.

The general structure of partially aromatic PA polymers and copolymers preferred for the manufacture of laser sintered objects is shown in the general formula given below, where the structural uniqueness required to obtain low crystallinity is further described below:

k, L ═ unsubstituted or substituted C₂-C₂₀A linear or cyclic alkyl group,

Ar₄and Ar₅Is an unsubstituted or substituted mono-or polycyclic aromatic hydrocarbon, linked linearly or non-linearly, with Rf₄、Rf₅、Rf₆And/or Rf₇Independently for H, the substituents can be optionally selected from:

Rf₄，Rf₅，Rf₆，Rf₇each independently selected from C₁-C₆Linear, branched or cyclic alkyl and alkoxy groups and aryl groups, preferably selected from the group consisting of Me, i-Pr, t-Bu, Ph, wherein K, L, Ar₄And Ar₅Each of which independently has one or more substituents Rf₄、Rf₅、Rf₆、Rf₇(for unsubstituted K, L, Ar₄And Ar₅Then, Rf₄，Rf₅，Rf₆，Rf₇＝H)，

T, U, V, W ═ NH-CO-or-CO-NH-,

d is a lower integer greater than 0 and preferably lower than 12, more preferably from 1 to 6 and especially from 1 to 3,

e. f and g are 0 or lower integers, preferably less than 12, more preferably from 1 to 6 and especially from 1 to 3,

n represents the degree of polymerization.

In the above formulae, the indices d, e, f and g denote the number of the respective repeating units of the polymer and of the respective repeating units of the copolymer, respectively, wherein one or more units of the same type, for example the unit denoted by index d, can be located between units of another type, for example the units denoted by indices e, f and/or g. The following examples of polyamide polymers to be used according to the invention illustrate the above general formula of the polyamide polymers.

The PA6-3-T polyamide polymer used according to the invention has the following repeating units:

repeating unit A:

repeating unit B:

in the repeating unit A, K is represented by Rf₄A n-hexane chain disubstituted in the 2-position and monosubstituted in the 4-position, T is-NH-CO-and d ═ 1, e ═ 0, Ar₄Is unsubstituted 1, 4-phenylene, V is-CO-NH-and f ═ 1 and g ═ 0. This gives the second repeating unit B because there are 2 possibilities for the reaction of the substituted hexanediamine with terephthalic acid. In the repeating unit B, K is substituted by Rf₄A n-hexane chain disubstituted in the 2-position and monosubstituted in the 4-position, T is-NH-CO-and d ═ 1, e ═ 0, Ar₄Is unsubstituted 1, 4-phenylene, V is-CO-NH-and f ═ 1 and g ═ 0.

The following two examples of polyamide polymers PA6T/6I and PA MXD6 used according to the invention are examples of polyamide polymers having aromatic groups for the nonlinear linking.

The polyamide PA6T/6I copolymer has 2 different repeat units (see repeat units A and B in the following formulae).

Repeating unit A:

repeating unit B:

in the repeating unit a, K is an unsubstituted n-hexane chain, T is-NH-CO-and d ═ 1, e ═ 0, Ar₄Is unsubstituted 1, 4-phenylene, V is-CO-NH-and f ═ 1 and g ═ 0. In the repeating unit B, K is an unsubstituted n-hexylene chain, T is-NH-CO-and d ═ 1, e ═ 0, Ar₄Is unsubstituted 1, 3-phenylene, V is-CO-NH-and f ═ 1 and g ═ 0. The degree of polymerization n of this PA copolymer represents n₁And n₂The sum of (a) and (b).

The following example shows a further polyamide to be used according to the invention, namely poly-m-xylylene adipamide (polyamide MXD6) having units for nonlinear linking in the backbone chain. According to the above formula, for the polyamide MXD6, K is an unsubstituted n-butane chain, T is-CO-NH-and d-1, e-0, Ar₄Is unsubstituted 1, 3-xylylene, V is-NH-CO-and f ═ 1 and g ═ 0, wherein the following formula represents MXD6

Wherein n represents the degree of polymerization.

In the case of polyamides, the branching groups can be formed from the aliphatic residues K and L and/or by one or more substituents Rf₄、Rf₅、Rf₆And Rf₇Substituted aromatic hydrocarbon Ar₄And Ar₅Provided is a method.

In the case of polyamides, the bulky groups are selected from aromatic or non-aromatic groups. In particular, structural units selected from the group consisting of phenylene, naphthalene, anthracene, biphenyl, fluorene, terphenyl, decalin or norbornane need to be considered.

In the remaining polymers, similar considerations apply to the bulky groups given for polyamides.

The structural properties explained for PAEK polymers and copolymers and for PA (co) polymers can likewise be applied to other polymer or copolymer materials which have already been mentioned by way of example. Those skilled in the art will recognize that corresponding structural modifications can be made, with the effect of reducing crystallinity in the three-dimensional object produced.

Furthermore, the powder may be a composite powder comprising, in addition to the matrix of the respective polymer, copolymer or blend, one or more fillers and/or additives. Fillers can be used to further improve the mechanical properties of the manufactured object. For example, carbon fibers, glass fibers, kevlar fibers, carbon nanotubes, or fillers, preferably having a low aspect ratio (glass beads, aluminum sand, etc.) or mineral fillers such as titanium dioxide may be incorporated into the powder comprising at least one polymer or copolymer. In addition, processing aids which improve the processability of the powders, for example free-flowing agents such as those of the Aerosil series (e.g. Aerosil R974, Aerosil R812, Aerosil 200), or other functional additives such as heat stabilizers, oxidation stabilizers, coloring pigments (carbon black, graphite, etc.) may be used.

From the findings of the present invention it can be concluded that the following structural characteristics or modifications of the polymer or copolymer ensure a low crystallinity in the manufactured object and are therefore particularly preferred when a specific type of polymer or copolymer is preselected, for example among Polyaryletherketones (PAEK), Polyarylethersulfones (PAES), polyamides, polyesters, polyethers, polyolefins, polystyrene, polyphenylene sulfides, polyvinylidene fluoride, polyphenylene oxides, polyimides and copolymers comprising at least one of the aforementioned polymers:

a) a preselection of polymers or copolymers having at least one of the following structural characteristics and/or modifications:

(i) at least one branching group within the backbone chain of the polymer or copolymer, with the proviso that when a Polyaryletherketone (PAEK) is used, the branching group is an aromatic structural unit in the backbone chain of the polymer or copolymer;

(ii) modifying at least one end group of the backbone chain of the polymer or copolymer;

(iii) at least one bulky group in the backbone chain of the polymer or copolymer, with the proviso that when a Polyaryletherketone (PAEK) is used, the bulky group is not selected from the group consisting of phenylene, biphenylene, naphthylene, and CH₂-or isopropylidene-linked aromatic hydrocarbons;

(iv) at least one aromatic group non-linearly connecting the backbone chains,

b) use comparativelyHigh molecular weight M_nOr M_wOr a certain viscosity of the melt,

c) using a long chain length or a high degree of polymerization,

d) mixing or blending is performed by blending of at least two different polymers or copolymers.

The following examples are merely illustrative of the invention and they should not be construed as limiting the scope of the invention in any way. Examples and modifications, or other equivalents thereof, will become apparent to those skilled in the art upon reading the entire disclosure.

Examples

The density of the three-dimensional object produced was measured according to ISO 1183 on a Kern 770-60 balance having a Satorius densitometer YDK 01. The porosity of the object can be determined from the density, where the theoretical density of 100% crystalline polymer, the theoretical density of amorphous polymer and the crystallinity of the manufactured polymer object are known. The crystallinity in the manufactured object can be measured by dynamic differential calorimetry (DCC or DSC) according to DIN 53765.

If the theoretical density value of the polymer is not known, the porosity can also be determined by micro-computer tomography (micro-computer tomography) suitable equipment is for example μ -CT40 supplied by SCANCOMedical AG, Br ü ttissellen, Switzerland.

The following examples are illustrative only and should not be considered in a limiting sense.

Reference examples

From a particle size having an average particle diameter of 48 μmStructure of cloth unmodified PEEK (commercially available from Victrex Plc Co., Thornton Cleveleys, Lancasire FY 54 QD, Great Britain) powder made with the PEEK polymer having M_n23,000 and M_wMolecular weight 65,000 and 0.15kN s/m²Is heat treated in an oven at a temperature above the glass transition temperature.

Having a density of 0.45g/cm³The bulk density PEEK powder of (a) was processed on a laser sintering machine of the P700 type, which has been modified by the EOS company for high temperature applications. The temperature of the process chamber was 335 ℃.

After the laser sintering process was completed, the cooling rate was controlled by post-heating between 335 ℃ and the Tg (145 ℃) of PEEK. The cooling rate showed a maximum average of 0.3 ℃/min.

The three-dimensional part produced had the following properties:

density 1.316g/cm³

Degree of crystallinity (by DSC) 52%

Porosity (calculated from density/crystallinity) 1.4%

Tensile Strength test (AST)_mD638，Type I)：

Young's modulus 4500MPa

Tensile strength of 44MPa

Elongation at break 1.04%

Example 1 (according to the invention)

Powders producible from structurally modified PAEKs having the following structural formula

The powder has an average particle size distribution of <100 μm and is heat treated in an oven at a temperature above the glass transition temperature.

PAEK powder was processed on a laser sintering machine of type P700, which has been modified by the EOS company for high temperature applications. The temperature of the processing chamber is for example 10 c below the melting point of the PAEK powder.

After the laser sintering process was completed, the cooling rate was controlled by post-heating between the temperature of the process chamber and the Tg of the PAEK, such that the cooling rate showed a maximum average of 0.3 ℃/min.

Example 2 (according to the invention)

Powder producible from structurally modified PEEK having the following structural formula

The powder has an average particle size distribution of 50 μ M, wherein the PEEK polymer has M_n32,000 and M_wA molecular weight of 65,000, heat treated in an oven at a temperature above the glass transition temperature.

PEEK powder was processed on a laser sintering machine of the P700 type, which has been modified by EOS corporation for high temperature applications. The temperature of the process chamber is, for example, 335 ℃.

After the laser sintering process was completed, the cooling rate was controlled by post-heating between 335 ℃ and the Tg of PEEK (about 145 ℃) such that the cooling rate showed a maximum average of 0.3 ℃/min.

Example 3 (according to the invention)

Powder producible from polyamide PA6-3-T having the following structural formula

Repeating unit A:

repeating unit B:

The polyamide powder was processed on a laser sintering machine of type P700, which has been modified by the EOS company for high temperature applications. The temperature of the processing chamber is for example 5 ℃ below the melting point of the polyamide.

After the laser sintering process is complete, the cooling rate is controlled by post-heating between the temperature of the process chamber and the Tg of the polyamide, such that the cooling rate shows a maximum average of 0.3 ℃/min.

Example 4 (according to the invention)

Powder producible from a structurally modified polyethylene PE-LLD (Linear Low Density) having the following structural formula

R ═ butyl, hexyl or octyl

n, m is an integer such that there is a ratio of 15 to 30 short chain branches per 1000 carbon atoms,

it may have an average particle size distribution of <150 μm.

The PE-LLD powder was processed on a laser sintering machine of type P390 from EOS. The temperature of the processing chamber is, for example, 5 ℃ below the melting point of the PE-LLD powder.

After the laser sintering process was completed, the cooling rate of the process chamber at 40 ℃ was controlled such that the cooling rate showed a maximum average of 0.2 ℃/minute.

Example 5 (according to the invention)

Powder producible from a structurally modified polyethylene PE-HD (high density) having the following structural formula

R ═ methyl

n, m is an integer such that there is a ratio of 15 to 30 short chain branches per 1000 carbon atoms

It may have an average particle size distribution of <150 μm.

The PE-HD powder was processed on a laser sintering machine of type P390 from EOS. The temperature of the processing chamber is for example 5 ℃ lower than the melting point of the PE-HD powder.

Example 6 (according to the invention)

A ratio of recurring units each comprising at least one 1, 4-phenylene unit to recurring units each comprising at least one 1, 3-phenylene unit of 80:20, a melting point of 367 ℃ and an average particle size d₅₀Heat treated PEKK powder (model PEKK-C, commercially available from OPM corporation, Enfield, CT, USA) 55 μm was sintered by laser at model P700, which has been modified by EOS corporation to be suitable for high temperature applicationsAnd (4) machining. The temperature of the process chamber is 343 ℃. The cooling rate showed a maximum average of 0.3K/min.

The laser sintered parts had the following properties on average:

density: 1.246g/cm³

Tensile strength (ISO 527-2):

young's modulus: 4200MPa

Tensile strength: 39MPa

Elongation at break: 1.0 percent

Example 7 (according to the invention)

A ratio of repeating units each comprising at least one 1, 4-phenylene unit to repeating units each comprising at least one 1, 3-phenylene unit of 60:40, a melting point of 297 ℃ and an average particle size d₅₀Heat treated PEKK powder (model PEKK-SP, commercially available from OPM corporation, Enfield, CT, USA) 60 μm was processed on a laser sintering machine model P700 which has been modified by EOS corporation to be suitable for high temperature applications. The temperature of the process chamber was 286 deg.c. The average cooling rate between 286 ℃ and 250 ℃ was higher than 0.3K/min. Between 250 ℃ and Tg, the average cooling rate is determined by the natural heat loss.

The laser sintered parts had the following properties on average:

density: 1.285g/cm³

Tensile strength (ISO 527-2):

young's modulus: 3900MPa

Tensile strength: 69MPa

Elongation at break: 1.9 percent.

Claims

1. Method for producing a three-dimensional object from a powder by a selective sintering process using electromagnetic radiation, wherein the powder comprises a polymer or copolymer having at least one of the following structural characteristics:

(iv) at least one aromatic group non-linearly connecting the backbone chains,

wherein the glass transition temperature T of the polymer or copolymer_GThe range is 50 to 300 ℃.

2. A method according to claim 1, wherein successive layers of the object to be formed from the curable powder material are subsequently cured at locations corresponding to the cross-section of the object; and/or

In which method the electromagnetic radiation is provided by a laser.

3. A method according to claim 1 or 2, comprising a predetermined and/or controlled cooling step after the sintering step.

4. A method according to claim 3, wherein the cooling step is applied to the object after completion of the object, requiring a cooling rate of from 0.01 to 10 ℃/min from the T of the polymer or copolymer contained in the powder_mCooling to a temperature of 1-50 ℃ lower than T of the polymer or copolymer contained in the powder_GWherein T is_mIs the melting point and T of the polymer or copolymer contained in the powder_GIs the glass transition temperature of the polymer or copolymer.

5. The method according to claim 1, wherein the powder comprises a polymer or copolymer having at least one property selected from the group consisting of:

melting point T in the range from 100 ℃ to 450 ℃_m；

A number average M of at least 10,000_nOr a weight average M of at least 20,000_w；

And

a degree of polymerization n of 10 to 10,000.

6. The method of claim 1, wherein the polymer or copolymer contains at least one aromatic group having at least one characteristic selected from the group consisting of:

the aromatic groups are in the repeat units of the backbone chain; and

each of the aromatic groups is independently selected from unsubstituted or substituted monocyclic or polycyclic aromatic hydrocarbons.

7. The method according to claim 6, wherein the aromatic groups are each independently selected from the group consisting of 1, 4-phenylene, 4,4 ' -biphenylene, 4,4 ' -isopropylidenediphenylene, 4,4 ' -diphenylsulfone, 1,4-, 1,5-, 2, 6-naphthylene, 4,4 "-p-biphenylene.

8. The process according to claim 1, wherein the aromatic group for nonlinear linking according to modification (iv) has at least one property selected from the group consisting of:

at least one non-linear linking aromatic group is contained in the repeating units of the backbone chain; and

the polymer or copolymer contains at least one additional, linear linking aromatic group different from the non-linear linking aromatic group and/or at least one branching group in the backbone chain.

9. The process according to claim 8, wherein the aromatic groups for the nonlinear linkage are selected from the group consisting of 1, 2-and 1, 3-phenylene, 1, 3-xylylene, 2,4 '-and 3, 4' -biphenylene, and 2, 3-and 2, 7-naphthylene.

10. The method according to claim 8, wherein the polymer or copolymer contains at least one additional, linear linking aromatic group different from the non-linear linking aromatic group and/or at least one branching group in the repeating units of the backbone chain.

11. The process according to claim 8 or 10, wherein the aromatic groups for linear linkage are each independently selected from the group consisting of 1, 4-phenylene, 4,4 ' -biphenylene, 4,4 ' -isopropylidenediphenylene, 4,4 ' -diphenylsulfone, 1,4-, 1,5-, 2, 6-naphthylene, 4,4 "-p-biphenylene and 2, 2-bis- (4-phenylene) -propane.

12. The process according to claim 1, wherein according to the improvement (i) the branching group is an aliphatic, aromatic or heteroaromatic hydrocarbon having at least one substituent or one side chain, and in the case of the use of Polyaryletherketones (PAEK) the branching group is an aromatic structural unit in the backbone chain of the polymer or copolymer.

13. The method according to claim 12, wherein the side chains are each independently selected from the group consisting of C₁-C₆Unbranched or branched chain or ring-shaped alkyl or alkoxy groups and aryl groups.

14. The method according to claim 13, wherein the side chains are each independently selected from the group consisting of methyl, isopropyl, tert-butyl or phenyl.

15. The process according to claim 1, wherein according to the improvement (ii), the terminal group of the backbone chain is modified with a terminal alkyl, alkoxy, ester and/or aryl group.

16. The method according to claim 1, wherein the bulky group is a polycyclic aromatic or non-aromatic group.

17. The method according to claim 16, wherein the bulky group is selected from phenylene, naphthalene, anthracenyl, biphenyl, fluorene, terphenyl, decahydronaphthalene or norbornane.

18. The method of claim 1, wherein the polymer or copolymer is formed based on Polyamide (PA), Polyaryletherketone (PAEK), Polyarylethersulfone (PAES), polyester, polyether, polyolefin, polystyrene, polyphenylene sulfide, polyvinylidene fluoride, polyphenylene oxide, polyimide, or a block copolymer comprising at least one of the foregoing polymers.

19. The method of claim 18, wherein the polymer or copolymer is formed based on a Polyamide (PA), a Polyaryletherketone (PAEK), a Polyarylethersulfone (PAES), or a block copolymer comprising at least one of the foregoing polymers.

20. The process according to claim 19, wherein the block copolymer is a Polyaryletherketone (PAEK)/Polyarylethersulfone (PAES) -diblock copolymer or a PAEK/PAES/PAEK-triblock copolymer.

21. The method of claim 1, wherein the polymer is a Polyaryletherketone (PAEK) formed based on Polyetheretherketone (PEEK), Polyetherketoneketone (PEKK), Polyetherketone (PEK), Polyetheretherketoneketone (PEEKK), Polyetheretherketone (PEEEK), or a copolymer comprising at least one of the foregoing polymers.

22. The process according to claim 21, wherein the Polyaryletherketone (PAEK) -based polymer or copolymer has a density of from 0.05 to 1.0kN s/m²And/or a degree of polymerization n of 10 to 1,000.

23. The method of claim 21, wherein the Polyetherketoneketone (PEKK) polymer or copolymer comprises 1, 4-phenylene as the aromatic group for linear linkage and 1, 3-phenylene as the aromatic group for non-linear linkage in the backbone chain of the polymer.

24. The method of claim 23 wherein the Polyetherketoneketone (PEKK) polymer or copolymer comprises 1, 4-phenylene as the aromatic group for linear attachment and 1, 3-phenylene as the aromatic group for non-linear attachment in the repeating units of the backbone chain.

25. The method of claim 24, wherein the ratio of repeat units each comprising at least one 1, 4-phenylene unit to repeat units each comprising one 1, 3-phenylene unit is from 90/10 to 10/90.

26. The method of claim 25, wherein said ratio is 70/30-10/90.

27. The method of claim 25, wherein said ratio is 60/40-10/90.

28. Three-dimensional object obtained by selective sintering of a polymer, copolymer or polymer blend in powder form using electromagnetic radiation, wherein the polymer or copolymer used for the powder has at least one of the following structural characteristics:

(iv) at least one aromatic group non-linearly connecting the backbone chains,

29. The three-dimensional object according to claim 28, wherein the polymer or copolymer is as defined in any one of claims 5 to 27.

30. A manufacturing system, comprising: apparatus for manufacturing a three-dimensional object from a powder by selective sintering using electromagnetic radiation of the powder, and a powder comprising at least one polymer or copolymer as defined in any of claims 1 or 5 to 27, wherein the apparatus comprises a temperature control device arranged to set a predetermined cooling operation of the object after the object has been manufactured.

31. The manufacturing system according to claim 30, wherein in the apparatus, the cooling rate set by the temperature control device depends on the type of the polymer, copolymer, or polymer blend contained in the powder; and/or

Wherein the temperature control device is set according to a predetermined type of polymer, copolymer or polymer blend.

32. Use of a polymer powder in a process for the manufacture of a three-dimensional object by means of selective electromagnetic radiation sintering, wherein the polymer is preselected from the group consisting of polymers or copolymers having at least one of the following structural characteristics:

(iv) at least one aromatic group non-linearly connecting the backbone chains,

wherein the polymer is orGlass transition temperature T of the copolymer_GThe range is 50 to 300 ℃.

33. Use according to claim 32, wherein the polymer or copolymer is as defined in any one of claims 5 to 27.