Rosin air entraining agent, its preparation method and application

Abstract

The application relates to the technical field of building materials and chemical building materials, and discloses a rosin air entraining agent, a preparation method and application thereof. The method comprises the following steps: carrying out a condensation dehydration reaction on maleic rosin, an amine compound and polypropylene glycol, and then mixing the obtained reaction product with water; wherein the amine compound is at least one of monoethanolamine, triethanolamine and triethylenetetramine; and the molecular weight of the polypropylene glycol is 150-600. The rosin air entraining agent prepared according to the method has a better air entraining effect.

Description

Technical Field

[0001] This invention relates to the field of building materials and chemical building materials technology, specifically to a rosin air-entraining agent, its preparation method, and its application. Background Technology

[0002] Inorganic non-metallic building materials (such as gangue-based concrete, coal-based solid waste sprayed grout, and various composite building materials) are core substrates in geotechnical engineering, and are essentially typical brittle composite materials with multiphase coupling. The service performance and long-term durability of these materials highly depend on the optimized control of their internal microscopic pore structure, among which impermeability, crack resistance, and freeze-thaw resistance are recognized as three key performance indicators. Impermeability directly affects the intrusion path of environmental media (water, salt ions, and chloride ions, etc.), crack resistance determines the material's damage tolerance under high-temperature environments, external loads, and shrinkage stress, and freeze-thaw resistance relates to the structural stability of materials in colder regions during repeated freeze-thaw cycles. Existing engineering practices have shown that these properties are significantly positively correlated with the later strength development of composite materials. For example, introducing an appropriate amount of uniformly closed air bubbles can effectively alleviate internal stress concentration, while inferior air bubbles can become the initial defect source for crack propagation. However, in most current engineering applications, the impermeability, crack resistance, and frost resistance of inorganic non-metallic building materials are often difficult to guarantee due to the lagging development of supporting air-entraining agent technology. This contradiction has become a key bottleneck restricting the development of building materials towards high performance and long service life. The reasons for this are twofold: First, the current engineering acceptance system still focuses on compressive strength as the core indicator. For example, the assessment weight of impermeability grade and shrinkage of shotcrete materials in coal mine roadways is insufficient. This leads designers and construction companies to limit the functional positioning of air-entraining agents to assisting in improving work performance, rather than systematically improving the microstructure of the material. Second, due to uneven construction management levels, some projects arbitrarily adjust the dosage of air-entraining agents in pursuit of the fluidity and pumpability of concrete mixtures, neglecting the precise control of air bubble quality (such as size, distribution, and stability). Third, the market supply of high-performance air-entraining agents is severely unbalanced. High-quality air-entraining agents need to meet multiple technical requirements, such as miniaturization of bubbles (≤100μm), toughening of the wall film (inhibiting rupture), and uniform distribution. Their research and development involves complex scientific issues such as surfactant molecular design, bubble stability dynamics control, and compatibility optimization with the gelation system. At present, the relevant technology accumulation in China is weak, and imported products are difficult to promote on a large scale due to their high cost.

[0003] Against this backdrop, the market has been forced to adopt a large number of traditional surfactant-based chemical air-entraining agents (such as sodium dodecyl sulfate and sodium fatty alcohol polyoxyethylene ether sulfate). While these air-entraining agents can introduce air bubbles by reducing the surface tension of the liquid, their bubble structure has significant defects. These include wide bubble size distribution, high connectivity, and poor stability, leading to a significant increase in the porosity of concrete. Studies show that for every 1% increase in the proportion of ineffective bubbles, the compressive strength of the composite material can decrease by 5-8%, and the impermeability grade can drop by more than two levels. It should be noted that the improvement in the workability of the mixture by these air-entraining agents is limited to short-term dilution and viscosity reduction; they cannot simultaneously optimize water retention and cohesiveness, further exacerbating the risk of performance degradation in the later stages of the composite material.

[0004] Currently, air-entraining technology for inorganic non-metallic building materials (traditional concrete, coal mine shotcrete materials, etc.) faces significant discrepancies between its engineering application effects and long-term material performance requirements due to the difficulty in simultaneously achieving synergistic control of "bubble miniaturization, uniform distribution, and interface stability." The following are the technical bottlenecks encountered by three typical air-entraining agents: Traditional chemical air-entraining agents (such as sodium dodecyl sulfate, AES, and other surfactant-type agents) rely on reducing the liquid-gas interfacial tension to generate bubbles. However, due to their molecular structure, these bubbles tend to coalesce due to their high surface energy, forming large, coarse bubble clusters with wide particle size distributions (typically >100μm) and high connectivity. Even with modification using biionic surfactants, while excessive bubble aggregation can be suppressed to some extent, the bubble diameter is still significantly larger than the ideal range (engineering requirements are typically <80μm). Furthermore, the gas volume is extremely sensitive to dosage fluctuations; even small changes in dosage can lead to a deviation of over 20% in the bubble volume, severely impacting the stability of concrete's impermeability and strength.

[0005] Plant-derived triterpenoid saponin air-entraining agents, while exhibiting superior bubble refinement capabilities (average diameter reduced to 60-80 μm) compared to chemical air-entraining agents due to the polyhydroxy structure and strong interfacial activity of natural molecules, have ironically become obstacles to engineering applications due to their excessively excellent bubble control properties. Furthermore, the overly strong interfacial interaction between triterpenoid saponin molecules and the cementitious system leads to excessive bubble wall toughness and excessively low surface energy. The strong mutual attraction between bubbles due to differences in interfacial tension results in the ball-bead effect failure, making it difficult for bubbles to disperse evenly in the slurry and easily causing them to accumulate into large clusters. This defect directly weakens its effect on improving the workability of concrete mixtures. Firstly, uneven bubble distribution leads to an increased slurry flow gradient and increased pumping resistance. Secondly, locally enriched bubbles cannot effectively isolate capillaries, resulting in a 15-20% increase in bleeding rate compared to rosin-based air-entraining agents.

[0006] Rosin-based air-entraining agents, as a classic type of air-entraining agent, generate hydrophobic groups through the condensation reaction of rosin acid and formaldehyde, theoretically balancing bubble stability and dispersibility. However, these products are limited by the natural heterogeneity of rosin raw materials. The resin acid composition of rosin from different origins and tree species can fluctuate by about 15%, resulting in a wide molecular weight distribution and significant differences in the density of hydrophobic groups in the condensation products. This instability of raw materials directly leads to two major engineering problems. First, there is a solubility defect: rosin acid condensates easily form micelle aggregates in aqueous systems, requiring the addition of dispersants to aid dissolution, increasing the complexity of the process. Second, product quality fluctuates greatly, with batch-to-batch deviations in bubble introduction reaching about 10%, severely affecting concrete performance.

[0007] In summary, the analysis shows that developing a high-performance air-entraining agent that combines the characteristics of bubble micronization, uniform distribution, and structural stabilization, thereby significantly improving the workability of concrete while also enhancing its impermeability, crack resistance, and frost resistance, has become an urgent need to promote the technological upgrading of inorganic non-metallic building materials. Currently, no air-entraining agent technology solution has been found that synergistically optimizes these multi-dimensional performance characteristics. Summary of the Invention

[0008] The purpose of this invention is to overcome the problems of poor overall performance in terms of bubble micronization, uniform distribution, and structural stabilization of existing air-entraining agents, and to provide a rosin air-entraining agent, its preparation method, and its application. The rosin air-entraining agent prepared according to the method of this invention has superior air-entraining effect.

[0009] To achieve the above objectives, the present invention provides a method for preparing a rosin air-entraining agent, the method comprising: subjecting maleic rosin, amine compounds and polypropylene glycol to a condensation dehydration reaction, and then mixing the resulting reaction product with water; The amine compound is at least one of monoethanolamine, triethanolamine, and triethylenetetramine; The molecular weight of the polypropylene glycol is 150-600.

[0010] Preferably, the mass ratio of the maleic rosin, the amine compound, and the polypropylene glycol is 1:(0.5-4):(0.1-0.5).

[0011] Preferably, the conditions for the condensation dehydration reaction include: a temperature of 120-180℃ and a time of 1-3h.

[0012] Preferably, the mass ratio of the reaction product to the water is 1:3-10.

[0013] Preferably, the softening point of the Malaysian rosin is 105-135℃.

[0014] Preferably, the acid value of the Malaysian rosin is 200-230 mg KOH / g.

[0015] Preferably, the molecular weight of the polypropylene glycol is 200-400.

[0016] Preferably, the specific mixing process includes: cooling the reaction product to 90-100°C once, then mixing the cooled reaction product with water once and cooling the resulting mixture to 60-80°C, and then mixing the mixture with water a second time.

[0017] Preferably, the mixing time for one mixing cycle is 0.5-2 hours.

[0018] A second aspect of the present invention provides a rosin air-entraining agent prepared by the method described above.

[0019] The third aspect of this invention provides the application of the rosin air-entraining agent described above in the preparation of inorganic non-metallic building materials.

[0020] According to the preparation method of the rosin air-entraining agent described in this invention, through molecular structure design and functional group regulation, on the one hand, the inherent hydrophobic framework of the maleic rosin molecule can be retained, utilizing its interfacial affinity with the cementitious system to promote the uniform generation of microbubbles; on the other hand, polypropylene glycol segments are grafted onto the side chains of the maleic rosin molecule, and amine compounds are introduced as carboxyl blocking agents. The steric hindrance effect of the polypropylene glycol segments effectively prevents excessive bubble coalescence, while its hydrophilic structure can form a stable film at the bubble interface, inhibiting the formation and existence of large bubbles. Thus, a synergistic unity of "precise air entrainment" and "selective defoaming" is achieved at the molecular level. The rosin air-entraining agent prepared according to the method described in this invention has superior air-entraining effect. Detailed Implementation

[0021] The following provides a detailed description of specific embodiments of the present invention. It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0022] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0023] The preparation method of the rosin air-entraining agent of the present invention includes: carrying out a condensation and dehydration reaction of maleic rosin, amine compounds and polypropylene glycol, and then mixing the resulting reaction product with water; The amine compound is at least one of monoethanolamine, triethanolamine, and triethylenetetramine; The molecular weight of the polypropylene glycol is 150-600.

[0024] In the method described in this invention, the mass ratio of the maleic rosin, the amine compound, and the polypropylene glycol can be 1:(0.5-4):(0.1-0.5), preferably 1:(1-3.5):(0.2-0.4).

[0025] In the method described in this invention, the conditions for the condensation-dehydration reaction may include: a temperature of 120-180°C and a time of 1-3 hours. Preferably, the conditions for the condensation-dehydration reaction include: a temperature of 130-160°C and a time of 1.5-2.5 hours. The condensation-dehydration reaction can be carried out in a conventional reaction vessel. The condensation-dehydration reaction can be carried out under stirring. The stirring rate can be 50-80 r / min, preferably 60-70 r / min.

[0026] In the method described in this invention, the mass ratio of the reaction product to the water can be 1:3-10, preferably 1:4-8.

[0027] In the method described in this invention, the softening point of the rosin is 105-135℃, preferably 110-125℃. The acid value of the rosin is 200-230 mg KOH / g, preferably 210-220 mg KOH / g. In a preferred embodiment, the rosin conforms to standard GB / T 14021-2009. The rosin can be purchased from Xiamen Chengfan New Materials Co., Ltd., and its grade is Rosin 107.

[0028] In the method described in this invention, preferably, the molecular weight of the polypropylene glycol is 200-400. More preferably, the molecular weight of the polypropylene glycol is 220-350. In a specific embodiment, the polypropylene glycol can be purchased from Jiangsu Haian Petrochemical Plant Co., Ltd., and its grade is polypropylene glycol 300.

[0029] In the method described in this invention, the specific mixing process includes: cooling the reaction product to 90-100°C once, then mixing the cooled reaction product with water once and cooling the resulting mixture to 60-80°C, and then mixing the mixture with water a second time. The first mixing time can be 0.5-2 hours, preferably 1-1.5 hours.

[0030] This invention also provides a rosin air-entraining agent prepared by the above method. This rosin air-entraining agent utilizes the steric hindrance effect of polypropylene glycol segments to precisely suppress the generation and stable existence of large bubbles (>100 μm), maintaining the initial air-entraining amount within a reasonable range. Simultaneously, it achieves fine control of bubble diameter, significantly improving the uniformity of bubble distribution without increasing the initial air-entraining amount. Furthermore, the carboxyl group blocking prevents the protonation and deprotonation reactions of maleic rosin molecules caused by fluctuations in the pH of the medium (hard water, acidic / alkaline environments), completely solving the problem of traditional rosin air-entraining agents' sensitivity to aqueous media.

[0031] This invention also provides the application of the rosin air-entraining agent in the preparation of inorganic non-metallic building materials.

[0032] The following examples further illustrate the rosin air-entraining agent, its preparation method, and its application according to the present invention. These examples are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following examples.

[0033] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods in the art. Unless otherwise specified, the experimental materials used in the following embodiments are commercially available.

[0034] Example 1 50 kg of Malaysian rosin (purchased from Xiamen Chengfan New Materials Co., Ltd., brand name Malaysian rosin 107, hereinafter the same) was added to the reaction vessel and heated to 85°C for softening. Then, 150 kg of monoethanolamine and 12.5 kg of polypropylene glycol (purchased from Jiangsu Haian Petrochemical Plant Co., Ltd., brand name polypropylene glycol 300, molecular weight 300, hereinafter the same) were added and heated to 140°C for condensation and dehydration reaction for 2 hours. The mixture was then allowed to cool naturally to 100°C, and then 278.5 kg of water was slowly added over 1 hour. After cooling to 70°C, 1000 kg of water was added to obtain rosin air-entraining agent A1.

[0035] Example 2 Add 50 kg of Malaysian rosin to a reaction vessel and heat it to 85°C to soften it. Then add 37.5 kg of triethanolamine and 25 kg of polypropylene glycol and heat it to 145°C for condensation and dehydration reaction for 2 hours. Let it stand and cool naturally to 100°C. Then slowly add 700 kg of water over 1 hour. After cooling to 70°C, add 312.5 kg of water to obtain rosin air-entraining agent A2.

[0036] Example 3 Add 50 kg of Malaysian rosin to a reaction vessel and heat it to 85°C to soften it. Then add 9 kg of triethylenetetramine, 16 kg of triethanolamine and 15 kg of polypropylene glycol, and heat it to 140°C for condensation and dehydration reaction for 2 hours. Let it stand and cool naturally to 100°C, and then slowly add 500 kg of water over 1 hour. After cooling to 70°C, add another 400 kg of water to obtain rosin air-entraining agent A3.

[0037] Example 4 Rosin air-entraining agent was prepared according to Example 1, except that the amount of polypropylene glycol was adjusted to 3 kg, resulting in rosin air-entraining agent A4.

[0038] Example 5 Rosin air-entraining agent was prepared according to Example 1, except that the amount of polypropylene glycol was adjusted to 30 kg, resulting in rosin air-entraining agent A5.

[0039] Example 6 Rosin air-entraining agent was prepared according to Example 1, except that the amount of monoethanolamine was adjusted to 250 kg, resulting in rosin air-entraining agent A6.

[0040] Example 7 Rosin air-entraining agent was prepared according to Example 1, except that the amount of monoethanolamine was adjusted to 20 kg, resulting in rosin air-entraining agent A7.

[0041] Example 8 Rosin air-entraining agent was prepared according to Example 1, except that after cooling to 70°C, the amount of water added was adjusted to 2000 kg, resulting in rosin air-entraining agent A8.

[0042] Example 9 Rosin air-entraining agent was prepared according to Example 1, except that Malaysian rosin was replaced with resin RESIN (brand name TYPE, softening point 90-100℃) to obtain rosin air-entraining agent A9.

[0043] Example 10 Rosin air-entraining agent was prepared according to Example 1, except that polypropylene glycol (purchased from Jiangsu Haian Petrochemical Plant Co., Ltd., brand name polypropylene glycol 300, molecular weight 300) was replaced with polypropylene glycol (purchased from Nantong Runfeng Petrochemical Co., Ltd., brand name polypropylene glycol 600, molecular weight 600) to obtain rosin air-entraining agent A10.

[0044] Comparative Example 1 Rosin entrainer was prepared according to the method of Example 1, except that monoethanolamine was replaced with diethylamide to obtain entrainer D1.

[0045] Comparative Example 2 Rosin air-entraining agent was prepared according to Example 1, except that polypropylene glycol (Jiangsu Haian Petrochemical Plant Co., Ltd., brand name polypropylene glycol 300, molecular weight 300) was replaced with polypropylene glycol (purchased from Dongfang Jianxing New Materials (Shandong) Co., Ltd., brand name PPG-700, weight average molecular weight 700) to obtain air-entraining agent D2.

[0046] Comparative Example 3 Sodium dodecyl sulfate was used as the air-entraining agent D3.

[0047] Comparative Example 4 A mixture of sodium dodecyl sulfate and organosilicon defoamer (purchased from Jinan Xinyingda Industrial Co., Ltd., brand name Xinyingda) in a mass ratio of 10:1 was used as air-entraining agent D4.

[0048] Comparative Example 5 Triterpenoid saponins (product name: triterpenoid saponin air-entraining agent, Shandong Hongquan Chemical Technology Co., Ltd., industrial grade, solid content 99%) were used as air-entraining agent D5.

[0049] Comparative Example 6 Maleic rosin was vacuum dehydrated at 120°C for 2 hours to remove moisture. Then, the dehydrated maleic rosin was added to a reaction vessel and heated to a molten state. Polyethylene glycol and zinc oxide were added at a mass ratio of 1:1 (zinc oxide to maleic rosin mass ratio of 1:100). The reaction was carried out at 200°C for 4 hours under a nitrogen atmosphere. After the acid value stabilized, the temperature was lowered to 150°C, and the mixture was poured out of the reaction vessel. After cooling and crushing, the gas-entraining agent D6 was obtained.

[0050] Test case The air-entraining performance of the air-entraining agents prepared in the above embodiments and comparative examples was tested according to the following methods: Add 20 mL of calcium hydroxide solution with a concentration of 0.6 wt‰ and 1.2 wt‰ prepared with an air-entraining agent to a saturated aqueous solution of calcium hydroxide, respectively (keep all operations consistent, shake horizontally for one minute), and use a 100 mL measuring cylinder to test the initial and 1-hr and 2-hr bubble heights of the measuring cylinder.

[0051] The air-entraining performance of the air-entraining agents prepared in the above embodiments and comparative examples is shown in Tables 1 and 2 below. Table 1 shows the air-entraining effect when the concentration of the air-entraining agent is 0.6 wt‰; Table 2 shows the air-entraining effect when the concentration of the air-entraining agent is 1.2 wt‰.

[0052] Table 1

[0053] Table 2

[0054] The results in Tables 1 and 2 show that the air-entraining agent prepared according to the method described in this invention has a significantly better air-entraining effect.

[0055] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing a rosin air-entraining agent, characterized in that, The method includes: subjecting maleic rosin, amine compounds and polypropylene glycol to a condensation dehydration reaction, and then mixing the resulting reaction product with water; The amine compound is at least one of monoethanolamine, triethanolamine, and triethylenetetramine; The molecular weight of the polypropylene glycol is 150-600.

2. The method according to claim 1, characterized in that, The mass ratio of the maleic rosin, the amine compound, and the polypropylene glycol is 1:(0.5-4):(0.1-0.5).

3. The method according to claim 1 or 2, characterized in that, The conditions for the condensation dehydration reaction include: a temperature of 120-180℃ and a time of 1-3 hours.

4. The method according to any one of claims 1-3, characterized in that, The mass ratio of the reaction product to the water is 1:3-10.

5. The method according to any one of claims 1-4, characterized in that, The softening point of the Malaysian rosin is 105-135℃; and / or, The acid value of the Malaysian rosin is 200-230 mg KOH / g.

6. The method according to any one of claims 1-5, characterized in that, The molecular weight of the polypropylene glycol is 200-400.

7. The method according to any one of claims 1-6, characterized in that, The specific mixing process includes: cooling the reaction product to 90-100°C once, then mixing the cooled reaction product with water once and cooling the resulting mixture to 60-80°C, and then mixing the mixture with water a second time.

8. The method according to claim 7, characterized in that, The mixing time for each mixing cycle is 0.5-2 hours.

9. A rosin air-entraining agent prepared by the method according to any one of claims 1-8.

10. The application of the rosin air-entraining agent according to claim 9 in the preparation of inorganic non-metallic building materials.

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