Search

CN-121159834-B - Colored polylactic acid oligomer, preparation method thereof and polylactic acid colorant

CN121159834BCN 121159834 BCN121159834 BCN 121159834BCN-121159834-B

Abstract

The invention discloses a colored polylactic acid oligomer, a preparation method thereof and a polylactic acid colorant, and belongs to the technical field of high polymer materials. The colored polylactic acid oligomer is prepared by directly initiating lactide to controllably open loop and polymerize through active amino groups in an organic dye, and the chemical structure of the colored polylactic acid oligomer is formed by bonding of the dye and a homogeneous polylactic acid molecular chain, so that the colored polylactic acid oligomer has excellent compatibility and dispersibility in a polylactic acid substrate, and can keep the original excellent performance of the substrate when the colored polylactic acid oligomer is used for coloring stock solution through blending. The molecular chain of the homogeneous polylactic acid in the colored polylactic acid oligomer is bonded on the amino group of the auxiliary chromophore of the dye instead of the chromophore, so that the colored polylactic acid oligomer can present the same hue as the corresponding dye, the color of the colored polylactic acid oligomer can be prepared according to the red-yellow-blue (RYB) hue circle law to present diversification, and the raw liquid coloring product can present the required color through simple blending.

Inventors

  • XU YINGJUN
  • WEI YING
  • WANG XUEFANG
  • WANG YUZHONG

Assignees

  • 青岛大学

Dates

Publication Date
20260512
Application Date
20250915

Claims (10)

  1. 1. A colored polylactic acid oligomer characterized by having a structure represented by the following formula (I): Formula (I) Wherein m is 1 or 2, n is 10 to 60, dye is a residue of an organic dye group, The organic dye has the structural formula of Or (b) Wherein R 1 is one of-H, -CH 3 , -OPh, -Cl and-Br; R 2 is one of-H, -NH 2 and-OH; R 3 is-H or-NH 2 ; r 4 is-H or-OH; r 5 is one of-H, -NH 2 and-NO 2 .
  2. 2. The colored polylactic acid oligomer according to claim 1, wherein the colored polylactic acid oligomer has a relative molecular mass of greater than 900 g/mol and less than 9000 g/mol.
  3. 3. The method for preparing the colored polylactic acid oligomer according to claim 1, wherein after the organic dye containing amino groups and lactide are melted and mixed, active amino groups in organic dye molecules directly initiate lactide to controllably carry out ring-opening polymerization under the action of a catalyst, and the organic dye is anthraquinone type or azo type disperse dye and has the structure shown in the following formula: Or (b) Wherein R 1 is one of-H, -CH 3 , -OPh, -Cl and-Br; R 2 is one of-H, -NH 2 and-OH; R 3 is-H or-NH 2 ; r 4 is-H or-OH; r 5 is one of-H, -NH 2 and-NO 2 .
  4. 4. The method for producing a colored polylactic acid oligomer according to claim 3, wherein the chemical structural formula of the organic dye is one of the following structural formulas: , , , , , , , 。
  5. 5. the method for producing a colored polylactic acid oligomer according to claim 3, wherein the production steps are as follows: Adding selected organic dye and lactide monomer into a reaction bottle, heating to 110-120 ℃ under the protection of inert atmosphere, continuously stirring for 20-30 minutes, and cooling the obtained organic dye/lactide mixture to room temperature after lactide is completely melted and uniformly mixed with the organic dye, wherein the molar ratio of the organic dye to the lactide monomer is 1:5-60; Adding a catalyst into the organic dye/lactide mixture obtained in the step (1), then carrying out lactide ring-opening polymerization under the protection of inert atmosphere, controlling the reaction temperature to be 120-130 ℃ and the reaction time to be 24-48 hours, wherein the molar ratio of the dosage of the catalyst to the amount of added lactide monomer is 1.1-1.3:1000; and (3) cooling the crude product obtained in the step (2) to room temperature, adding dichloromethane to dissolve the crude product completely, then adding the obtained solution into ice methanol dropwise to precipitate and suction-filter and separate, repeating the dissolution-precipitation cycle for a plurality of times, and drying the obtained purified product to constant weight to obtain the colored polylactic acid oligomer.
  6. 6. The method for producing a colored polylactic acid oligomer according to claim 3, wherein the catalyst is at least one of stannous octoate, stannous chloride, zinc lactate, zinc chloride and zinc acetate.
  7. 7. The method for producing a colored polylactic acid oligomer according to claim 3, wherein the lactide monomer is at least one of L-lactide, D-lactide and meso-lactide.
  8. 8. A polylactic acid colorant, characterized by comprising at least one color of the colored polylactic acid oligomer according to any one of claims 1-2 or the colored polylactic acid oligomer prepared by the preparation method according to any one of claims 3-7, wherein the color is red, blue, purple, yellow or orange.
  9. 9. The polylactic acid colorant according to claim 8, wherein the polylactic acid colorant is composed of 0 to 100wt.% of a red polylactic acid oligomer, 0 to 100wt.% of a yellow polylactic acid oligomer, and 0 to 100wt.% of a blue polylactic acid oligomer.
  10. 10. The polylactic acid colorant according to claim 8, wherein the polylactic acid colorant is used by adding the polylactic acid colorant into polylactic acid in a solution blending and/or melt blending manner to achieve stock solution coloring, and the addition amount of the polylactic acid colorant is 0.001-5 wt.%.

Description

Colored polylactic acid oligomer, preparation method thereof and polylactic acid colorant Technical Field The invention relates to the technical field of high polymer materials, in particular to a colored polylactic acid oligomer, a preparation method thereof and a polylactic acid colorant. Background Polylactic acid is a bio-based material that is renewable, degradable, chemically recyclable, safe and non-toxic. Polylactic acid has good processability, can be manufactured into fibers, films, engineering structural parts and the like through processing treatments such as spinning, film blowing, injection molding, 3D printing and the like, and is one of ideal choices for replacing petroleum-based plastics. In recent years, polylactic acid products have been applied to various fields of packaging, textile, automobile, agriculture, medical treatment and the like, but the color of the polylactic acid products is mainly white or semitransparent, and the increasingly growing demands of high-end, fashionable, personalized and the like in the consumer market are not met, for example, the polylactic acid products lack of color are limited in the aspects of high-end cosmetic color packaging, fashionable clothing and home textile production, color customization of automobile structural members and the like. Although the polylactic acid fiber can be dyed by disperse dye in the textile field, the dye-uptake is low, the color fastness is poor, a dyeing carrier and an auxiliary agent are required to be added, and in addition, the dyeing method can damage the mechanical property of the fiber and cannot be suitable for the dyeing of polylactic acid molding products prepared by other processing modes. The stock solution coloring technology is a coloring method that a coloring agent is added into a polymer solution or melt to obtain a colored polymer solution or melt, and the colored polymer product is directly prepared by a corresponding processing technology. At present, a color master batch method is generally adopted when the polylactic acid stock solution is colored, namely, a colorant is firstly mixed into a carrier to prepare color master batch, and then the color master batch is applied to the coloring processing of the polylactic acid stock solution. For example, patent CN106894103a and patent CN106633693a disclose solvent-borne color concentrates and PET-borne color concentrates for coloring polylactic acid fibers, which are prepared by loading pigments or dyes with solvent-borne and modified PET polyesters, respectively, and patent CN118531523a, patent CN108193316a and patent CN108193318B disclose polylactic acid-borne color concentrates for coloring polylactic acid fibers, which are prepared by directly loading colorants (pigments), environmental-friendly colorants (pigments and carbon black), and graphene, respectively, with polylactic acid. It is noted that these patents clearly indicate the need for the addition of dispersants or adjuvants such as polyethylene waxes, etc., to avoid agglomeration of the colorant and to promote its uniformity and stability of dispersion. However, the addition of heterogeneous and nondegradable dispersants or adjuvants can affect the overall degradability of the polylactic acid product, limit the recycling of the polylactic acid product and shorten the life cycle of the polylactic acid product, thereby destroying the original low-carbon property of the polylactic acid product, and the existence of the heterogeneous components can limit the use of the polylactic acid product in the field of high biosafety to a certain extent. Besides the masterbatch method, the application of the dye to the stock solution after the dye is chemically bonded with the polylactic acid molecular chain is also studied. For example, patent CN108084412B discloses a pre-spinning colorant for polylactic acid fiber, which is prepared by modifying a surface containing hydroxyl pigment (carbon black, aluminum powder or titanium pigment) with a silane coupling agent, and then performing polymerization reaction of the modified pigment and lactide in a solution to obtain the pre-spinning colorant for polylactic acid fiber, and the inventor subsequently discloses that black polylactic acid fiber is prepared based on the modified carbon black colorant in patent CN 110129915B. However, these two techniques can only produce polylactic acid products of black and white color system, and lack the color system. In addition, the colorant can be prepared into a catalyst for lactide ring-opening polymerization reaction to realize the coloration of the polylactic acid product. For example, patent CN115490837B, patent CN115612071B and The paper title of international journal ANGEWANDTE CHEMIE International Edition, the Combined SYNTHESIS AND Coloration of Poly (LACTIC ACID), all disclose The preparation of a colored catalyst by coordination of a dye and a metal, and The coloring is achieved by catalyzing ring-opening polymeriz