PLA color master batch for FDM consumables and application of PLA color master batch

Abstract

The invention discloses a PLA color master batch for FDM consumables and application of the PLA color master batch. The raw materials of the color master batch also contain polylactic acid, polyketone, a blue colorant and at least one ester compound represented by a general formula R1-COO-R2 in a weight ratio of 100: (5-10): (1-10): (1-5), R1 independently represents C1-C4 alkyl, and R2 independently represents C5-C12 alkyl; wherein the blue coloring agent is prepared by sequentially treating a disperse dye with a chitosan solution and a polyvinylpyrrolidone solution, grinding and sieving. The invention correspondingly provides application of the color master batch for the FDM consumable in preparation of a 3D printing wire, the 3D printing wire prepared from the color master batch as a raw material can be smoothly subjected to 3D printing, the total color difference of a product before and after printing is as low as 0.26-0.71, the color has no light jumping phenomenon under a D65 / D60 standard light source, and an expected blue effect can be perfectly presented.

Description

Technical Field

[0001] The present application relates to the field of masterbatches, and in particular to a PLA masterbatch for FDM consumables and applications thereof. Background Art

[0002] FDM (Fused Deposition Modeling) process The fused deposition manufacturing (FDM) process was successfully developed by American scholar Scott Crump in 1988. The FDM material is heated and melted in the nozzle, and the nozzle moves along the cross-sectional contour and filling trajectory of the part, while extruding the molten material. The material solidifies rapidly and condenses with the surrounding material to form various three-dimensional printed products. FDM materials are generally thermoplastic materials, such as wax, ABS, nylon, etc., which are fed in filament form. Depending on the needs, FDM materials often contain a certain proportion of coloring components to obtain products with different hues through FDM processing.

[0003] Compared with other colors, it is more difficult to prepare FDM products that appear blue. According to the principle of complementary colors, for an object to appear blue, the blue dye needs to absorb red light in the sunlight, and red light has the lowest energy in visible light, which means that the two energy levels where electron transitions occur in the material are very close, which requires that the stable substance that meets this requirement has sufficient stability. It is difficult for nature or organisms to form such substances. The currently available blue colorants (including blue pigments and blue dyes) vary in stability, resulting in the products being greatly affected by processing conditions. It is not easy to process blue products with sufficient expected coloring depth and no significant hue / shade changes.

[0004] Taking the related technology CN109054324A as an example, it discloses a colored microcrystalline cellulose, reinforced polylactic acid 3D printing material and a preparation method thereof. In Example 4, a light blue 3D printing material is prepared using a raw material containing blue microcrystalline cellulose. When 3D printing is performed using this 3D printing material, the obtained product exhibits a light yellow-green color, and the hue changes significantly before and after printing (light blue → light yellow-green). The colors of other embodiments are basically the same before and after printing.

[0005] In order to accurately prepare blue products of the expected color, how to suppress the changes in hue and color before and after 3D printing remains a problem to be solved in this field. Summary of the invention

[0006] In order to solve the problem of hue and color change of blue FDM consumables before and after printing, the present invention provides a PLA masterbatch for FDM consumables and application thereof.

[0007] In a first aspect, the present invention provides a PLA masterbatch for FDM consumables, which specifically adopts the following technical solution.

[0008] A masterbatch for FDM consumables, with polylactic acid as the main raw material, and the raw material also contains polyketone, blue colorant and at least one ester compound represented by the general formula R1-COO-R2, R1 independently represents a C1-C4 alkyl group, and R2 independently represents a C5-C12 alkyl group; the weight ratio of the polylactic acid, polyketone, blue colorant and ester compound is 100:(5-10):(1-10):(1-5);

[0009] The blue colorant is prepared by the following steps:

[0010] S1. Add disperse dye to a chitosan solution with a chitosan content of 10-30wt%, with a bath ratio of 1:(10-50), ultrasonically disperse for 20-40min, separate the solid phase and dry to obtain a pretreated dye; the disperse dye contains a blue disperse dye, and the blue disperse dye accounts for ≥50wt%;

[0011] S2, uniformly dispersing the pretreated dye obtained in step S1 in a polyvinyl pyrrolidone aqueous solution having a polyvinyl pyrrolidone content of 10-30wt%, with a bath ratio of 1:(10-50), stirring at a speed of 300-600 rpm for 20-30 min, separating the solid phase and drying to obtain a modified dye;

[0012] S3, grinding the modified dye obtained in step S2, passing it through a 2500-12500 mesh sieve, and obtaining a blue colorant for later use.

[0013] By adopting the above technical scheme, the masterbatch contains disperse dyes treated with chitosan solution and polyvinyl pyrrolidone solution in sequence as colorants, and is compounded with polyketone and ester compounds in a specific proportion. The FDM consumables prepared with this masterbatch appear blue, and because the disperse dye has been treated, it can withstand heat treatment during masterbatch preparation, consumable preparation and FDM printing, and can maintain sufficient color depth. Further FDM processed products are not prone to hue and color light deviations.

[0014] In the case of no special instructions, the bath ratio in this application refers to the weight ratio of the solid phase to the solution used for the dispersed solid phase. In the process of preparing the blue colorant, the bath ratio of step S1 and step S2 is controlled to be 1: (10-50), that is, compared with the amount of disperse dyes and chitosan solution per 1 weight part, it is 10-50 weight parts, compared with the amount of pre-treated dyes and polyvinylpyrrolidone aqueous solution per 1 weight part, it is 10-50 weight parts, and the amount is converted according to the above ratio during actual production and processing.

[0015] Furthermore, the chitosan solution is prepared by dissolving chitosan in 1-ethyl-3-methylimidazolium acetate. Chitosan is easily soluble in 1-ethyl-3-methylimidazolium acetate, and it is convenient to prepare the solution; in other embodiments, the chitosan solution can also be prepared with citric acid solvent, or water-soluble chitosan derivatives such as carboxymethyl chitosan can be used as raw materials to prepare the solution. Considering that step S2 requires the dye to be pretreated with a PVP aqueous solution, and the water solubility of chitosan is biased, it is preferred to dissolve chitosan in 1-ethyl-3-methylimidazolium acetate to prepare a chitosan solution, which can reduce the damage to the chitosan coating on the outside of the dye particles.

[0016] Further, R1 and R2 are both saturated alkyl groups. Further, the ester compound is n-pentyl acetate. Organic ester compounds can increase the color depth of the product and synergistically inhibit the change of hue and color. R1 and R2 can be linear or branched alkyl groups. As an example, R1 can be methyl, ethyl, propyl, isopropyl, butyl or isobutyl, and R2 can be n-pentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, lauryl, etc.

[0017] Furthermore, the blue disperse dye is selected from one or more of CI Disperse Blue 56, CI Disperse Blue 79, CI Disperse Blue 72, CI Disperse Blue 60, and CI Disperse Blue 87. Conventional blue disperse dyes can be used, and can produce products showing bright blue. According to the color requirements of the final product, a certain category of blue disperse dye can be used alone or different categories of blue disperse dyes can be mixed and used. Dyes of other color systems can also be used in combination with blue dyes to prepare purple and blue-green products.

[0018] Furthermore, the raw material also contains chopped carbon fibers, and the weight ratio of the chopped carbon fibers to the polylactic acid is (1-4):10. Furthermore, the aspect ratio of the chopped carbon fibers is (100-200):1. Chopped carbon fibers are beneficial to improving the physical and mechanical properties of composite materials and to preparing high-performance products. The weight ratio of the chopped carbon fibers to the polylactic acid can be specifically 1:10, 1:5, 3:10, 2:5, etc., and the aspect ratio of the chopped carbon fibers can be specifically 100:1, 110:1, 120:1, 130:1, 140:1, 150:1, 160:1, 170:1, 180:1, 190:1, 200:1, etc.

[0019] Furthermore, the raw material also contains a compatibilizer and a solubilizer, the weight ratio of the compatibilizer to the polylactic acid is (1-3):100, and the weight ratio of the solubilizer to the polylactic acid is (0.5-1):100. Further, the compatibilizer is a styrene-acrylonitrile-glycidyl methacrylate terpolymer, and the solubilizer is maleic anhydride grafted POE. The incorporation of the compatibilizer and the solubilizer can improve the compatibility of each component. The weight ratio of the compatibilizer to the polylactic acid can be specifically 1:100, 1.5:100, 2:100, 2.5:100, 3:100, etc., and the weight ratio of the solubilizer to the polylactic acid can be specifically 0.5:100, 0.6:100, 0.7:100, 0.8:100, 0.9:100, 1:100, etc.

[0020] In the second aspect, the present invention provides an application of a PLA masterbatch for FDM consumables in the preparation of 3D printing wires. When preparing 3D printing wires, the aforementioned PLA masterbatch can be mixed with PLA materials in proportion, and if necessary, a certain proportion of conventional additives such as lubricants and antioxidants can be mixed. The 3D printing wire prepared based on the aforementioned PLA masterbatch for FDM consumables can be smoothly 3D printed, and the processed products have almost no color phase and color light deviation. DETAILED DESCRIPTION

[0021] The present application is described in further detail below.

[0022] There is no restriction on the types of blue disperse dyes used in this institute. Blue disperse dyes can be used alone or mixed according to the different colors of products and conventional dyeing habits. A single variety of blue dye can be selected, or different varieties of blue disperse dyes can be selected for mixing, or blue disperse dyes can be mixed with other color disperse dyes to prepare blue, purple, and blue-green colorants. The following preparation examples only use CI Disperse Blue 56 (Jihua Jiangdong Chemical) as an example. In other preparation examples, blue disperse dyes provided by other manufacturers or other categories can be selected.

[0023] Preparation Example

[0024] <Preparation Example 1>

[0025] Preparation of blue colorant:

[0026] S1. Add CI Disperse Blue 56 to a chitosan solution with a chitosan content of 10 wt % at a bath ratio of 1:10, disperse by ultrasonication for 40 min, separate the solid phase by centrifugation and dry at 40° C. for 2 h to obtain a pretreated dye; wherein the chitosan solution is prepared by dissolving chitosan in 1-ethyl-3-methylimidazole acetate;

[0027] S2, uniformly dispersing the pretreated dye obtained in step S1 in a polyvinyl pyrrolidone aqueous solution having a polyvinyl pyrrolidone content of 30 wt%, with a bath ratio of 1:50, stirring at 600 rpm for 20 min, centrifuging to separate the solid phase and drying at 40° C. for 2 h to obtain a modified dye;

[0028] S3, grinding the modified dye obtained in step S2, passing it through a 2500 mesh sieve, and obtaining a powdered blue colorant for later use.

[0029] <Preparation Example 2-3>

[0030] The difference between Preparation Example 2-3 and Preparation Example 1 is that the process parameters of each step are different, see Table 1 for details.

[0031] Table 1. Process parameters of preparation examples

[0032]

[0033] Preparation Examples 2-3 all produced powdered blue colorants.

[0034] Comparative Preparation Example

[0035] <Comparative Preparation Example 1>

[0036] Preparation of blue colorant:

[0037] CI Disperse Blue 56 was added to a chitosan solution with a chitosan content of 20 wt% at a bath ratio of 1:30, and ultrasonically dispersed for 30 min. The solid phase was separated by centrifugation and dried at 40°C for 2 h, ground, and sieved through a 5000 mesh sieve to obtain a blue colorant for use.

[0038] <Comparative Preparation Example 2>

[0039] Preparation of blue colorant:

[0040] CI Disperse Blue 56 was added to a polyvinyl pyrrolidone aqueous solution with a polyvinyl pyrrolidone content of 20 wt% at a bath ratio of 1:30. The mixture was stirred at 450 rpm for 25 min. The solid phase was separated by centrifugation and dried at 40°C for 2 h. The mixture was ground and passed through a 5000 mesh sieve to obtain a blue colorant for use.

[0041] Example

[0042] <Examples 1-4>

[0043] A masterbatch for FDM consumables is prepared by mixing the raw materials in the proportions shown in Table 2 and extruding and granulating.

[0044] The specific preparation steps of masterbatch are as follows:

[0045] Add the raw materials in the proportions of Table 2 into a high-speed mixer, mix at a high speed at 45°C for 2-3 minutes, and mix evenly to obtain a mixture; add the mixture into a twin-screw extruder, melt-extrude into strips, wherein the extrusion temperature is 200°C, the extrusion speed is 320r / min, and the feeding speed is 20Hz; cool the extruded filaments in a water tank, convey them to a pelletizer for pelletizing, and then put the obtained PLA masterbatch into a dryer for drying, and after cooling, obtain the PLA masterbatch for FDM consumables.

[0046] The difference between Examples 1-4 is that different raw material ratios are used, as shown in Table 2.

[0047] Table 2. Raw material ratio table of the embodiment

[0048] raw material Example 1 Example 2 Example 3 Example 4 Polylactic acid / kg 50 50 50 50 Polyketone / kg 2.5 2.5 2.5 2.5 Blue colorant / kg 0.5 2 4 5 n-Amyl acetate / kg 0.5 0.5 0.5 0.5 Carbon fiber / kg 5 10 15 20 Compatibilizer / kg 0.5 0.75 1 1.5 Maleic anhydride grafted POE / kg 0.5 0.4 0.3 0.25

[0049] In Examples 1-4, the model of polylactic acid is Nature Works 4030D (Nature Works); the molecular weight of polyketone is 350-450 (BASF); and the compatibilizer is styrene-acrylonitrile-glycidyl methacrylate terpolymer, model (Jia Yi Rong polymer), other types of compatibilizers can also be used in other embodiments; the carbon fiber used is Toray T300 chopped carbon fiber (Toray, Japan), with a diameter of 7 μm and an aspect ratio of 100:1. Other brands and specifications of chopped carbon fibers can also be used in other embodiments; the purity of n-pentyl acetate is 99%; the maleic anhydride grafted POE model is FB521A (Jiayi polymer).

[0050] The blue colorant in Examples 1-4 was prepared from different preparation examples. The blue colorant in Example 1 was prepared from Preparation Example 1, the blue colorant in Example 2 was prepared from Preparation Example 2, the blue colorant in Example 3 was prepared from Preparation Example 3, and the blue colorant in Example 4 was prepared from Preparation Example 2.

[0051] <Example 5-6>

[0052] Example 5 is based on Example 4, except that 4 kg of polyketone is added for every 50 kg of polylactic acid.

[0053] Example 6 is based on Example 4, except that 5 kg of polyketone is added for every 50 kg of polylactic acid.

[0054] <Examples 7-8>

[0055] Example 7 is based on Example 4, except that 2 kg of n-pentyl acetate is added for every 50 kg of polylactic acid.

[0056] Example 8 is based on Example 4, except that 2.5 kg of n-pentyl acetate is added for every 50 kg of polylactic acid.

[0057] <Examples 9-10>

[0058] Example 9 is based on Example 4, except that an equal amount of hexyl acetate is used to replace n-pentyl acetate.

[0059] Example 10 is based on Example 4, except that an equal amount of lauryl acetate is used instead of n-pentyl acetate.

[0060] Comparative Example

[0061] <Comparative Example 1-2>

[0062] Comparative Example 1 is based on Example 4, except that the blue colorant is prepared according to Comparative Preparation Example 1.

[0063] Comparative Example 2 is based on Example 4, except that the blue colorant is prepared according to Comparative Preparation Example 2.

[0064] <Comparative Examples 3-4>

[0065] Comparative Example 3 is based on Example 4, except that an equal amount of polylactic acid is used instead of polyketone.

[0066] Comparative Example 4 is based on Example 4, except that an equal amount of polylactic acid is used to replace n-pentyl acetate.

[0067] Application Examples

[0068] <Application Example 1-10>

[0069] The PLA masterbatches for FDM consumables prepared in Examples 1-10 were used as raw materials to prepare 3D printing filaments according to the following method:

[0070] The raw materials are weighed in proportions of 90% polylactic acid, 4% PLA masterbatch for FDM consumables, 2% nano titanium dioxide, 3% SEBS and 1% PEG according to their mass percentages, put into a high-speed mixer and mixed for 5 minutes, then taken out to obtain a mixture; the mixture is fed into the feeding port of a twin-screw extruder, the temperature of the twin-screw extruder is 150-210°C, and the speed is 50rpm; the PLA filament extruded from the die is cooled by a first cooling water trough and a second cooling water trough respectively to obtain a reddish blue 3D printing filament with a diameter of 1.65±0.05mm.

[0071] The blue 3D printing filament prepared in the application example was used for 3D printing test. The printing temperature was 200°C, the printing process was smooth, the product had no warping, and the size was stable.

[0072] Comparative Application Examples

[0073] <Comparative Application Examples 1-4>

[0074] The difference between comparative application examples 1-4 and application example 4 is that the PLA masterbatches used for FDM consumables are the masterbatches prepared in comparative examples 1-4 respectively.

[0075] Performance Testing

[0076] Sample A was prepared by referring to the methods of Examples 1-10 / Comparative Examples 1-4. Raw materials were weighed and mixed according to the proportions of Examples 1-10 / Comparative Examples 1-4, and the extrusion die was replaced. The molten mixed material was extruded at 200°C and cooled to form a sheet A. The wire prepared in Application Examples 1-10 / Comparative Application Examples 1-4 was 3D printed at 200°C to form a sheet B with the same thickness as the sheet A. Rectangular sheet samples were cut from the prepared sheets A and B as Sample A and Sample B, respectively.

[0077] Use a colorimeter to measure the ΔL, Δa, and Δb values ​​of sample A and sample B respectively. The measured results of sample A are recorded as ΔL0, Δa0, and Δb0, and the measured results of sample B are recorded as ΔL1, Δa1, and Δb1. Calculate the lightness difference (ΔL * ), red / green difference (Δa * ), yellow / blue difference (Δb * ):

[0078] ΔL * =ΔL1-ΔL0,

[0079] Δa * =Δa1-Δa0,

[0080] Δb * =Δb1-Δa0;

[0081] Further calculate the total color difference (ΔE * ):

[0082] ΔE * =[(ΔL * ) ^ 2+(Δa * ) ^ 2+(Δb * ) ^ 2] ^ 0.5.

[0083] Total color difference (ΔE * ) and the corresponding relationship between the visual effect of the human eye are shown in Table 3.

[0084] Table 3. Total color difference (ΔE * ) and the corresponding relationship table of human eye visual effects

[0085] Total color difference (ΔE*) range Human eye visual effect 0-1 The naked eye cannot distinguish color difference 1-2 The human eye can slightly detect color difference; if the color difference sensitivity is not high, it cannot be distinguished 2-3 The human eye can clearly distinguish color difference, which is relatively not very obvious 3.5-5 The color difference is very obvious 5 They look like two completely different colors.

[0086] The total color difference (ΔE*) of sample AB is used to characterize the color difference change of the material before and after 3D printing. The larger the color difference value, the more obvious the color difference before and after printing. The total color difference (ΔE*) is recorded as the final experimental result, as shown in Table 4.

[0087] Take each sample B separately, and have professionals who have received professional colorimetric training observe the color of the sample in a colorimetric box under D65 and D60 standard light sources respectively to confirm whether there is obvious color difference ("light jumping" phenomenon) of the sample under different light sources. The results are recorded in Table 4.

[0088] Table 4. Experimental results

[0089] Sample ΔE* Whether there is a flashing light Sample ΔE* Whether there is a flashing light Embodiment 1 / Application Example 1 0.26 none Embodiment 8 / Application Example 8 0.51 none Embodiment 2 / Application Example 2 0.63 none Embodiment 9 / Application Example 9 0.60 none Embodiment 3 / Application Example 3 0.71 none Embodiment 10 / Application Example 10 0.63 none Embodiment 4 / Application Example 4 0.58 none Comparative Example 1 / Comparative Application Example 1 2.41 none Embodiment 5 / Application Example 5 0.56 none Comparative Example 2 / Comparative Application Example 2 2.39 none Embodiment 6 / Application Example 6 0.55 none Comparative Example 3 / Comparative Application Example 3 1.51 none Embodiment 7 / Application Example 7 0.54 none Comparative Example 4 / Comparative Application Example 4 1.64 none

[0090] From the data in Table 4, we can see that:

[0091] The blue 3D printing filament prepared by using the masterbatch of the present invention as a raw material has high color stability, and the total color difference (ΔE*) before and after 3D printing is as low as 0.26-0.71, the color difference degree cannot be distinguished by human eyes, and the product has no "light jumping" phenomenon under the D65 / D60 standard light source.

[0092] At the same time, it can be seen from the experimental results that only treating disperse dyes with chitosan solution or polyvinyl pyrrolidone solution has a poor effect on inhibiting the change of blue hue and color before and after printing; the addition of polyketone and ester compounds in the masterbatch has a synergistic effect of inhibiting the change of blue hue and color before and after printing.

[0093] The blue masterbatch of the invention is suitable for preparing various types of FDM consumables. The prepared consumables are used for FDM processing, have almost no color difference before and after printing, and can perfectly present an expected blue effect.

[0094] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A masterbatch for FDM consumables, with polylactic acid as the main raw material, characterized in that: The raw material further contains polyketone, a blue colorant and at least one ester compound represented by the general formula R1-COO-R2, wherein R1 independently represents a C1-C4 alkyl group and R2 independently represents a C5-C12 alkyl group; the weight ratio of the polylactic acid, the polyketone, the blue colorant and the ester compound is 100:(5-10):(1-10):(1-5); The blue colorant is prepared by the following steps: S1. Add disperse dye to a chitosan solution with a chitosan content of 10-30wt%, with a bath ratio of 1:(10-50), ultrasonically disperse for 20-40min, separate the solid phase and dry to obtain a pretreated dye; the disperse dye contains a blue disperse dye, and the blue disperse dye accounts for ≥50wt%; S2, uniformly dispersing the pretreated dye obtained in step S1 in a polyvinyl pyrrolidone aqueous solution having a polyvinyl pyrrolidone content of 10-30wt%, with a bath ratio of 1:(10-50), stirring at a speed of 300-600 rpm for 20-30 min, separating the solid phase and drying to obtain a modified dye; S3, grinding the modified dye obtained in step S2, passing it through a 2500-12500 mesh sieve, and obtaining a blue colorant for later use.

2. The masterbatch for FDM consumables according to claim 1, characterized in that: The chitosan solution is prepared by dissolving chitosan in 1-ethyl-3-methylimidazole acetate.

3. The masterbatch for FDM consumables according to claim 1, characterized in that: R1 and R2 are both saturated alkyl groups.

4. The masterbatch for FDM consumables according to claim 3, characterized in that: The ester compound is n-pentyl acetate.

5. The masterbatch for FDM consumables according to claim 1, characterized in that: The blue disperse dye is selected from one or more of CI Disperse Blue 56, CI Disperse Blue 79, CI Disperse Blue 72, CI Disperse Blue 60, and CI Disperse Blue 87.

6. The masterbatch for FDM consumables according to any one of claims 1 to 5, characterized in that: The raw material also contains short-cut carbon fibers, and the weight ratio of the short-cut carbon fibers to the polylactic acid is (1-4):

10.

7. The masterbatch for FDM consumables according to claim 6, characterized in that: The aspect ratio of chopped carbon fiber is (100-200):

1.

8. The masterbatch for FDM consumables according to any one of claims 1 to 5, characterized in that: The raw material also contains a compatibilizer and a solubilizer, the weight ratio of the compatibilizer to the polylactic acid is (1-3):100, and the weight ratio of the solubilizer to the polylactic acid is (0.5-1):

100.

9. The masterbatch for FDM consumables according to claim 8, characterized in that: The compatibilizer is a terpolymer of styrene-acrylonitrile-glycidyl methacrylate, and the solubilizer is maleic anhydride grafted POE.

10. Use of the masterbatch for FDM consumables according to any one of claims 1 to 9 in the preparation of 3D printing wires.

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