High-hardness rosin resin and preparation method thereof

Abstract

The invention relates to the field of resin processing, and particularly discloses high-hardness rosin resin and a preparation method thereof.The high-hardness rosin resin is prepared from first-grade rosin, pentaerythritol, phenolic aldehyde glycidyl ether, polypropylene glycol diglycidyl ether, nano-silicon dioxide, polysulfide rubber, an antioxidant and a catalyst; according to the manufacturing method, phenolic aldehyde glycidyl ether can react at medium and high temperatures, and low fluid viscosity at the high temperature is beneficial to stirring and uniform distribution of nano silicon dioxide. Phenolic diglycidyl ether is used as an epoxy group cross-linking agent, and a rigid network structure is constructed on a molecular level, so that the hardness of the resin can be greatly improved; the polypropylene glycol diglycidyl ether is introduced into a flexible chain segment, so that the brittleness is reduced. The nano silicon dioxide is uniformly dispersed at the periphery of the resin and is filled in gaps among molecular groups, so that the rigidity of the resin is macroscopically improved. The combination of the two can greatly improve the strength of the resin.

Description

Technical Field

[0001] This invention belongs to the field of resin processing, and specifically relates to a high-hardness rosin resin and its preparation method. Background Technology

[0002] Rosin, a natural mixture of diterpenic acids (mainly rosin acid), possesses advantages such as being renewable, biodegradable, having a rigid fused-ring structure, and abundant active carboxyl groups, making it an ideal platform for developing bio-based polymer materials. However, its inherent brittleness and insufficient thermal stability limit its application in high-performance structural materials (such as coatings, electronic packaging, and 3D printing), necessitating modifications to improve its hardness, strength, and dimensional stability. Traditional hardening methods (such as hydrogenation or polymerization) suffer from high energy consumption and low functional group utilization. Modern materials design emphasizes the synergy of "precise crosslinking" and "nanocomposite" technologies, constructing rigid network structures at the molecular level while introducing nanoparticles to enhance interfacial interactions, achieving a balance between hardness and toughness.

[0003] Enhancing intrinsic stiffness through covalent / dynamic crosslinking and optimizing stress distribution using nanoparticle interface engineering can break through the performance bottlenecks of natural rosin, providing a new paradigm for the design of bio-based functional materials. Therefore, studying a dual-track strategy of crosslinking network construction and nanocomposite reinforcement to improve the hardness of rosin resin is an important research topic. Summary of the Invention

[0004] The purpose of this invention is to provide a high-hardness rosin resin with significantly improved hardness and its preparation method.

[0005] To achieve the above objectives, the present invention provides a high-hardness rosin resin comprising, by weight: 55%-75% primary rosin, 15%-20% pentaerythritol, 5%-8% phenolic glycidyl ether, 3%-5% polypropylene glycol diglycidyl ether, 1%-3% nano-silica, 2%-4% polysulfide rubber, 0.02%-0.04% antioxidant, and 3.5%-4.9% catalyst.

[0006] As an improvement to the above scheme, the antioxidant is selected as antioxidant 1010, and the catalyst includes 0.4%-0.6% zinc soap catalyst, 0.1%-0.3% tertiary amine catalyst, and 3%-4% polyetheramine D230 by mass ratio.

[0007] A method for preparing the above-mentioned high-hardness rosin resin includes the following steps:

[0008] a. Raw material preparation: Prepare grade 1 rosin and grind it to 80-100 mesh, with an acid value of 160-170 mg KOH / g;

[0009] b. Pre-reaction: Primary rosin is added to the reaction vessel and heated to 140-160℃ under nitrogen protection to melt;

[0010] c. Esterification reaction: Add pentaerythritol and zinc soap catalyst, heat to 180-200℃, esterify for 2-3 hours, and reduce the acid value to 6-10 mgKOH / g; cool to 120-140℃, add phenolic diglycidyl ether, polypropylene glycol diglycidyl ether and nano silica, stir for 30-50 min, and keep warm for 1-2 h.

[0011] d. Crosslinking and curing: Cool to 80-100℃, add polysulfide rubber, polyetheramine D230, tertiary amine catalyst, and antioxidant, stir for 20-30 minutes, and keep warm for 1-2 hours;

[0012] e. Post-treatment: Heat to 120-130℃, filter to remove catalyst residue, and then inject rosin resin into the mold for curing.

[0013] As an improvement to the above scheme, in step a, the surface of nano-silica is modified with KH-560 (epoxysilane), and the amount of KH-560 used is 1%-3% of the mass of the nanoparticles.

[0014] The present invention has the following beneficial effects:

[0015] Phenolic diglycidyl ether, as an epoxy group crosslinking agent, constructs a rigid network structure at the molecular level, which can significantly improve the hardness of the resin. Polypropylene glycol diglycidyl ether introduces flexible segments, reducing brittleness. Nano-silica is uniformly dispersed around the resin, filling the gaps between molecular clusters, and macroscopically increasing the rigidity of the resin. The combination of the two can significantly improve the strength of the resin.

[0016] Both phenolic diglycidyl ether and polypropylene glycol diglycidyl ether are suitable for medium- and high-temperature reactions. The resin has a low viscosity when in a medium- and high-temperature molten state, which facilitates stirring and thus improves the efficiency and uniformity of mixing nano-silica. Detailed Implementation

[0017] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. Where the terms "first," "second," and "third" are used for descriptive purposes and to distinguish technical features, they should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the sequential relationship of the indicated technical features.

[0018] This invention discloses a high-hardness rosin resin with significantly improved hardness and its preparation method.

[0019] A high-hardness rosin resin comprises, by weight: 55%-75% primary rosin, 15%-20% pentaerythritol, 5%-8% phenolic glycidyl ether, 3%-5% polypropylene glycol diglycidyl ether, 1%-3% nano-silica, 2%-4% polysulfide rubber, 0.02%-0.04% antioxidant, and 3.5%-4.9% catalyst.

[0020] As an improvement to the above scheme, the antioxidant is selected as antioxidant 1010, and the catalyst includes 0.4%-0.6% zinc soap catalyst, 0.1%-0.3% tertiary amine catalyst, and 3%-4% polyetheramine D230 by mass ratio.

[0021] In this application, primary rosin provides a rigid framework (resin acid content ≥88%); pentaerythritol is used for tetrafunctional crosslinking to increase network density (acid value after esterification <8mgKOH / g); phenolic glycidyl ether serves as an epoxy group crosslinking agent, and polypropylene glycol diglycidyl ether introduces flexible segments to reduce brittleness; polysulfide rubber serves as a dynamic crosslinking toughening agent; nano-silica is uniformly dispersed within the resin to enhance its rigidity. Zinc soap catalyst is used for the esterification reaction, and both tertiary amine catalyst and polyetheramine D230 can accelerate epoxy curing. Antioxidants are used to prevent resin oxidation and discoloration.

[0022] A method for preparing the above-mentioned high-hardness rosin resin includes the following steps:

[0023] a. Raw material preparation: Prepare grade 1 rosin and grind it to 80-100 mesh, with an acid value of 160-170 mg KOH / g;

[0024] b. Pre-reaction: Primary rosin is added to the reaction vessel and heated to 140-160℃ under nitrogen protection to melt;

[0025] c. Esterification reaction: Add pentaerythritol and zinc soap catalyst, heat to 180-200℃, esterify for 2-3 hours, and reduce the acid value to 6-10 mgKOH / g; cool to 120-140℃, add phenolic diglycidyl ether, polypropylene glycol diglycidyl ether and nano silica, stir for 30-50 min, and keep warm for 1-2 h.

[0026] d. Crosslinking and curing: Cool to 80-100℃, add polysulfide rubber, polyetheramine D230, tertiary amine catalyst, and antioxidant, stir for 20-30 minutes, and keep warm for 1-2 hours;

[0027] e. Post-treatment: Heat to 120-130℃, filter to remove catalyst residue, and then inject rosin resin into the mold for curing.

[0028] As an improvement to the above scheme, in step a, the surface of nano-silica is modified with KH-560 (epoxysilane), and the amount of KH-560 used is 1%-3% of the mass of the nanoparticles.

[0029] This application employs the controlled variable method, summarizing the parameter differences of rosin resins obtained with different ratios of phenolic diglycidyl ether, polypropylene glycol diglycidyl ether, and nano-silica through the following five examples. The specific parameters of the experimental steps in Example 1 are as follows:

[0030] Raw material preparation: Based on a total mass of 1 kg, the composition includes 65.46% primary rosin, 20% pentaerythritol, 5% phenolic glycidyl ether, 3% polypropylene glycol diglycidyl ether, 1% nano-silica, 2% polysulfide rubber, 0.02% antioxidant, and 3.5% catalyst (containing 0.4% zinc soap catalyst, 0.1% tertiary amine catalyst, and 3% polyetheramine D230). Example 5 serves as a blank control group without glycidyl ether and nano-silica. In this control group, the mass of primary rosin was increased to compensate for the aforementioned missing components.

[0031] Pre-reaction: Primary rosin is added to the reactor and heated to 160℃ under nitrogen protection to melt; Esterification reaction: Pentaerythritol and zinc soap catalyst are added, the temperature is raised to 180℃, and esterification is carried out for 2 hours until the acid value decreases to below 10mgKOH / g; then the temperature is lowered to 120℃, phenolic diglycidyl ether, polypropylene glycol diglycidyl ether and nano silica are added, stirred for 30 min, and kept at this temperature for 1 h; Crosslinking and curing: The temperature is lowered to 80℃, polysulfide rubber, polyetheramine D230, tertiary amine catalyst and antioxidant are added, stirred for 30 min, and kept at this temperature for 1 h; Post-treatment: The temperature is raised to 120℃, filtered to remove catalyst residue, and then rosin resin is injected into a mold for curing.

[0032] Grade A rosin Phenolic diglycidyl ether Polypropylene glycol diglycidyl ether Nano silica Example 1 63.46% 5% 3% 1% Example 2 64.46% 5% 3% 0 Example 3 56.46% 8% 5% 3% Example 4 69.46% 0 0 3% Example 5 72.46% 0 0 0

[0033] Table 1. Parameters adjusted in the experiment

[0034] Shore hardness (D) Tensile strength (MPa) Heat distortion temperature (°C) Elongation at break (%) Example 1 86 55 105 4.5 Example 2 80 51 92 4.3 Example 3 90 62 111 5 Example 4 85 52 95 4.6 Example 5 63 41 87 1.9

[0035] Table 2 Experimental Conclusions

[0036] As shown in Table 2, adding the two glycidyl ethers and nano silica can significantly improve the hardness of rosin resin, and the improvement ratio is slightly greater than that of adding glycidyl ether or nano silica alone.

[0037] Phenolic diglycidyl ether, as an epoxy group crosslinking agent, constructs a rigid network structure at the molecular level, which can significantly improve the hardness of the resin. Polypropylene glycol diglycidyl ether introduces flexible segments, reducing brittleness. Nano-silica is uniformly dispersed around the resin, filling the gaps between molecular clusters, and macroscopically increasing the rigidity of the resin. The combination of the two can significantly improve the strength of the resin. Both phenolic diglycidyl ether and polypropylene glycol diglycidyl ether are suitable for medium- and high-temperature reactions. The resin has a low viscosity in a medium- and high-temperature molten state, which facilitates stirring, thereby improving the efficiency and uniformity of mixing nano-silica.

[0038] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A high-hardness rosin resin, characterized in that, It includes the following components by weight: 55%-75% Grade A rosin, 15%-20% pentaerythritol, 5%-8% phenolic glycidyl ether, 3%-5% polypropylene glycol diglycidyl ether, 1%-3% nano silica, 2%-4% polysulfide rubber, 0.02%-0.04% antioxidant, and 3.5%-4.9% catalyst.

2. The high-hardness rosin resin according to claim 1, characterized in that: The antioxidant is selected from antioxidant 1010, and the catalyst includes 0.4%-0.6% zinc soap catalyst, 0.1%-0.3% tertiary amine catalyst, and 3%-4% polyetheramine D230 by mass.

3. A method for preparing the high-hardness rosin resin according to claim 2, characterized in that... Includes the following steps: a. Raw material preparation: Prepare grade 1 rosin and grind it to 80-100 mesh, with an acid value of 160-170 mg KOH / g; b. Pre-reaction: Primary rosin is added to the reaction vessel and heated to 140-160℃ under nitrogen protection to melt; c. Esterification reaction: Add pentaerythritol and zinc soap catalyst, heat to 180-200℃, esterify for 2-3 hours, and reduce the acid value to 6-10 mgKOH / g; cool to 120-140℃, add phenolic diglycidyl ether, polypropylene glycol diglycidyl ether and nano silica, stir for 30-50 min, and keep warm for 1-2 h. d. Crosslinking and curing: Cool to 80-100℃, add polysulfide rubber, polyetheramine D230, tertiary amine catalyst, and antioxidant, stir for 20-30 minutes, and keep warm for 1-2 hours; e. Post-treatment: Heat to 120-130℃, filter to remove catalyst residue, and then inject rosin resin into the mold for curing.

4. The preparation method according to claim 3, characterized in that: In step a, the surface of nano-silica is modified with KH-560 (epoxysilane), and the amount of KH-560 used is 1%-3% of the mass of the nanoparticles.