Unsaturated polyester resin material containing potassium bromide composite accelerant and preparation method of unsaturated polyester resin material

Abstract

The invention belongs to the technical field of unsaturated polyester resin materials, and particularly relates to an unsaturated polyester resin material containing a potassium bromide composite accelerant and a preparation method of the unsaturated polyester resin material. The unsaturated polyester resin material containing the potassium bromide composite accelerant comprises the following raw materials: unsaturated polyester resin, the composite accelerant and an initiator, the unsaturated polyester resin is prepared from the following raw materials: dihydric alcohol, saturated dibasic acid, unsaturated dibasic acid, a polymerization inhibitor, an antioxidant and styrene. According to the unsaturated polyester resin material containing the potassium bromide composite accelerator, the composite accelerator is adopted to catalyze isomerization crosslinking of the unsaturated polyester resin, so that the curing speed of the unsaturated polyester resin is increased, the production efficiency is ensured, and the production cost is reduced; the bending strength and the bending modulus of the product prepared by adopting the composite accelerant are improved, and the impact resistance of the product is enhanced; the invention further provides a preparation method, and the preparation process is simple.

Description

Technical Field

[0001] The present invention belongs to the technical field of unsaturated polyester resin materials, and particularly relates to an unsaturated polyester resin material containing a potassium bromide composite accelerator and a preparation method thereof. Background Art

[0002] Unsaturated polyester resin is a thermosetting resin with excellent mechanical properties, corrosion resistance, electrical insulation and processing flexibility. Due to its comprehensive properties and economy, unsaturated polyester resin occupies an important position in both traditional industries and emerging fields. The curing speed of the resin has a significant impact on the production efficiency, product quality, physical properties, appearance, process control and cost of downstream customers of unsaturated polyester resin.

[0003] When the curing speed is too slow, a series of systematic problems will occur: First, the material remains in a low-viscosity fluid state for a long time, making it difficult for internal bubbles to be effectively discharged through natural defoaming or vacuum treatment. At the same time, reinforcing materials (such as glass fiber, carbon fiber) settle and delaminate due to the lack of timely curing restraint, resulting in uneven distribution of local reinforcing phases; Second, the uncured resin continues to flow under the action of gravity and surface tension, causing the product size to deviate from the design tolerance and defects such as flow marks and depressions on the surface; Insufficient curing will also reduce the crosslinking density of the material, showing characteristics of increased brittleness and deteriorated mechanical properties; In addition, the extended open time significantly increases the environmental sensitivity during the production process, and pollutants such as dust and moisture easily invade the material surface, causing quality problems such as sagging and color spots, increasing energy consumption and working hours, and raising production costs.

[0004] CN114249864A discloses an accelerator for unsaturated polyester resin, its preparation method and application. By using methanol, copper acetate, cobalt isooctanoate and water as the accelerator, the gelling time of the unsaturated polyester resin is shortened, the stability of the product system is ensured, the curing effect is good, and the hardness is high; CN114751669A also discloses an accelerator for unsaturated polyester resin. By introducing copper naphthenate or copper isooctanoate into the pure cobalt isooctanoate curing system, cobalt isooctanoate is used to accelerate the curing process of the resin, shorten the gelling time, and improve the curing efficiency of the resin. Copper naphthenate or copper isooctanoate reduces the exothermic peak temperature of the unsaturated polyester resin and inhibits the heat release amount of the unsaturated polyester resin. The combined use of the two can shorten the gelling time of the resin, reduce the exothermic peak temperature during the resin curing process, and effectively prevent problems such as cracking and deformation during the curing process of thick samples; however, the above patents all use the compounding of copper-containing organic matter and cobalt isooctanoate solution. Although the cobalt ion content is reduced, the copper organic matter will change color (such as oxidation and blackening) under light or humid and hot environments, affecting the appearance of the product. To inhibit side effects (such as discoloration and agglomeration), it may be necessary to mix with auxiliaries such as antioxidants and ultraviolet stabilizers, increasing the complexity of the formula. In addition, copper ions will interfere with the crosslinking network structure, hinder the normal crosslinking reaction, resulting in an uneven or incomplete crosslinking network structure, and then leading to a decrease in the mechanical strength of the cured resin. Finally, copper, as a transition metal, will catalyze the oxidative degradation of the resin and accelerate the aging of the polymer material.

[0005] In summary, it is necessary to develop an unsaturated polyester resin material, through the design of its components, which can not only significantly improve the curing speed of the unsaturated polyester resin but also have no negative impact on the product performance. Summary of the Invention

[0006] The purpose of the present invention is to overcome the defects existing in the prior art, and provide an unsaturated polyester resin material containing potassium bromide composite accelerator. By using the composite accelerator, it catalyzes the isomerization crosslinking of the unsaturated polyester resin, improves the curing speed of the unsaturated polyester resin, ensures the production efficiency, and reduces the production cost; for the product prepared by using the composite accelerator, both the flexural strength and the flexural modulus are improved, and the impact resistance of the product is enhanced; the present invention also provides its preparation method, and the preparation process is simple.

[0007] The unsaturated polyester resin material containing potassium bromide composite accelerator of the present invention comprises the following raw materials in parts by mass: 80-150 parts of unsaturated polyester resin, 0.6-2 parts of composite accelerator, and 0.8-3.0 parts of initiator; the unsaturated polyester resin is composed of the following raw materials in parts by mass: 50-80 parts of diol, 20-35 parts of saturated dibasic acid, 30-40 parts of unsaturated dibasic acid, 0.01-1 part of inhibitor, 0.1-1 part of antioxidant, and 30-50 parts of crosslinking agent; the composite accelerator is composed of an organic cobalt salt solution and potassium bromide, and the mass ratio of the organic cobalt salt solution to potassium bromide is (0.5-3):1.

[0008] The organic cobalt salt in the organic cobalt salt solution is one or two of cobalt isooctanoate and cobalt naphthenate, preferably the cobalt isooctanoate solution sold by Tianjin Miaoyang Chemical Co., Ltd. The cobalt ion concentration in the cobalt isooctanoate solution is 8wt.%. In the commercially available cobalt isooctanoate solution, the main components are cobalt isooctanoate and solvent, and the solvent is ethanol.

[0009] The initiator is one or two of methyl ethyl ketone peroxide and cyclohexanone peroxide, preferably methyl ethyl ketone peroxide.

[0010] The diol is one or more of diethylene glycol, ethylene glycol, and propylene glycol, preferably diethylene glycol.

[0011] The saturated dibasic acid is one or more of phthalic anhydride (phthalic anhydride), isophthalic acid, terephthalic acid, and adipic acid, preferably phthalic anhydride; the unsaturated dibasic acid is one of maleic anhydride (maleic anhydride) and fumaric acid, preferably maleic anhydride.

[0012] The antioxidant is one or two of triphenyl phosphite and 2,6-di-tert-butyl-p-cresol (antioxidant 264), preferably triphenyl phosphite.

[0013] The inhibitor is hydroquinone, and the crosslinking agent is styrene.

[0014] The preparation method of the unsaturated polyester resin material containing potassium bromide composite accelerator comprises the following steps: (1) Put the diol, saturated dibasic acid, unsaturated dibasic acid, antioxidant, and inhibitor into a reaction kettle, heat up to 160-210°C, keep the temperature for reaction for 1-6h until the acid value is 50-150mgKOH / g and the cone-plate viscosity is 1.0-1.5P. Subsequently, carry out vacuum dehydration at -0.06MPa~-0.1MPa for 1-5h until the cone-plate viscosity of the system is 2.0-20P and the acid value is 20-45mgKOH / g. After exhausting with nitrogen, cool down to 185°C, add the inhibitor and stir evenly, continue to cool down to 155°C, add the crosslinking agent for dilution, and stir evenly to obtain unsaturated polyester resin; among them, the mass ratio of the inhibitor added twice is 1:2; (2) Place unsaturated polyester resin, composite accelerator, and initiator in a treatment kettle, stir evenly, pour into a mold, and cure at room temperature to obtain an unsaturated polyester resin material containing potassium bromide composite accelerator.

[0015] Preferably, for the unsaturated polyester resin material containing potassium bromide composite accelerator, in applications in the fields of construction and decoration (such as countertops and washbasins, floors and walls, exterior wall decoration, etc.) and industrial equipment (including anti-corrosion equipment, wear-resistant parts, etc.), a certain proportion of inorganic fillers need to be added during preparation to improve its performance.

[0016] The unsaturated polyester resin material containing potassium bromide composite accelerator of the present invention, on the basis of traditional organic cobalt salts, introduces inorganic potassium bromide. Potassium bromide itself has weak initiation activity, but in the presence of cobalt ions, potassium ions can have a synergistic effect with cobalt ions, generating free radical reaction interference, changing the electron distribution, making the O-O bond in peroxides more easily broken, thereby accelerating the decomposition rate of the initiator and indirectly promoting the reaction; at the same time, bromine has a strong electron-withdrawing ability, which further makes the rearrangement reaction of double bond electron pairs easier to proceed, further catalyzing the isomerization cross-linking of unsaturated polyester resin. The inorganic potassium bromide has high light transmittance and chemical inertness, and its properties are more stable and not prone to high-temperature decomposition reactions.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) For the unsaturated polyester resin material containing potassium bromide composite accelerator of the present invention, potassium bromide and organic cobalt salt are introduced as composite accelerators. The presence of potassium ions can generate free radical reaction interference, change the decomposition mechanism of peroxides, and accelerate the decomposition rate of the initiator. In addition, potassium bromide can catalyze the isomerization cross-linking of unsaturated polyester resin, further changing the curing reaction rate of unsaturated polyester resin, and significantly shortening the curing time.

[0018] (2) For the unsaturated polyester resin material containing potassium bromide composite accelerator of the present invention, compared with the traditional curing system, the cobalt ion concentration is low, and potassium bromide is used, reducing the probability of side reactions occurring during the curing cross-linking of unsaturated polyester resin and ensuring the mechanical strength of the unsaturated polyester resin material.

[0019] (3) The preparation method of the unsaturated polyester resin material containing potassium bromide composite accelerator of the present invention has a simple preparation process. Description of the Drawings

[0020] Figure 1 is the highest exothermic peak during the curing process of the unsaturated polyester resin in Example 1 of the present invention; Figure 2 is the highest exothermic peak during the curing process of the unsaturated polyester resin in Example 2 of the present invention; Figure 3This is the highest exothermic peak during the curing process of the unsaturated polyester resin in Example 3 of the present invention; Figure 4 This is the highest exothermic peak during the curing process of the unsaturated polyester resin in Comparative Example 1 of the present invention. Detailed implementation manners

[0021] The present invention will be further described below in conjunction with examples and comparative examples. The raw materials used in the examples and comparative examples are all conventional commercially available raw materials unless otherwise specified, and the process methods used in the examples and comparative examples are all conventional methods in the art unless otherwise specified.

[0022] The raw materials used in the examples and comparative examples are described as follows: Cobalt isooctanoate solution: The main components are cobalt isooctanoate and ethanol, and the cobalt ion concentration in the solution is 8 wt.%, purchased from Tianjin Miaoyang Chemical Co., Ltd.

[0023] The unsaturated polyester resins used in the examples and comparative examples are described as follows. The unsaturated polyester resin is composed of the following raw materials in parts by mass: 56.0 parts of diethylene glycol, 27.0 parts of phthalic anhydride, 31.0 parts of maleic anhydride, 0.05 part of hydroquinone, 0.15 part of triphenyl phosphite, and 35.5 parts of styrene; the specific preparation process of the unsaturated polyester resin is as follows: Put the above-mentioned parts by mass of diethylene glycol, maleic anhydride, phthalic anhydride, triphenyl phosphite, and hydroquinone into a reaction kettle, heat up to 200 ± 5 °C, and keep the reaction for 3 h. The acid value is 87.5 ± 2.5 mgKOH / g, and the cone-plate viscosity is 1.15 ± 0.05 P. Subsequently, dehydrate under a vacuum of -0.09 MPa for 1 h. The cone-plate viscosity of the system is 5.5 ± 0.2 P, and the acid value is 30 ± 2 mgKOH / g. After exhausting with nitrogen, cool down to 185 °C, add hydroquinone and stir evenly, continue to cool down to 155 °C, add styrene for dilution, and stir evenly to obtain the unsaturated polyester resin; among them, the mass ratio of hydroquinone added twice is 1:2, and the total mass fraction of hydroquinone added is 0.05 part.

[0024] Example 1 The unsaturated polyester resin material containing potassium bromide composite accelerator includes the following raw materials in parts by mass: 100 parts of unsaturated polyester resin, 0.7 part of composite accelerator (the mass ratio of cobalt isooctanoate solution to potassium bromide is 1:1), and 1.0 part of methyl ethyl ketone peroxide; The unsaturated polyester resin is composed of the following raw materials in parts by mass: 56.0 parts of diethylene glycol, 27.0 parts of phthalic anhydride, 31.0 parts of maleic anhydride, 0.05 part of hydroquinone, 0.15 part of triphenyl phosphite, and 35.5 parts of styrene.

[0025] The preparation method of the unsaturated polyester resin material containing potassium bromide composite accelerator includes the following steps: (1) Diethylene glycol, maleic anhydride, phthalic anhydride, triphenyl phosphite, and hydroquinone are put into a reaction kettle, heated to 200 ± 5 °C, and kept at this temperature for reaction for 3 h. The acid value is 87.5 ± 2.5 mgKOH / g, and the cone-plate viscosity is 1.15 ± 0.05 P. Subsequently, water is removed under a vacuum of -0.09 MPa for 1 h. The cone-plate viscosity of the system is 5.5 ± 0.2 P, and the acid value is 30 ± 2 mgKOH / g. After purging with nitrogen, the temperature is lowered to 185 °C, hydroquinone is added and stirred evenly, then the temperature is further lowered to 155 °C, and styrene is added for dilution and stirred evenly to obtain unsaturated polyester resin. Among them, the mass ratio of hydroquinone added twice is 1:2, and the total mass fraction of hydroquinone added is 0.05 parts; (2) The unsaturated polyester resin and the composite accelerator are placed in a treatment kettle and stirred evenly. Subsequently, methyl ethyl ketone peroxide is added and stirred evenly, and then poured into a mold for curing at room temperature to form an unsaturated polyester resin material containing potassium bromide composite accelerator, and the gel time, the highest exothermic peak, the flexural strength, and the flexural modulus during the curing process are measured.

[0026] Example 2 The unsaturated polyester resin material containing potassium bromide composite accelerator comprises the following raw materials in mass fractions: 80 parts of unsaturated polyester resin, 0.6 part of composite accelerator (the mass ratio of cobalt octoate solution to potassium bromide is 3:1), and 3.0 parts of methyl ethyl ketone peroxide; The unsaturated polyester resin is composed of the following raw materials in mass fractions: 56.0 parts of diethylene glycol, 27.0 parts of phthalic anhydride, 31.0 parts of maleic anhydride, 0.05 part of hydroquinone, 0.15 part of triphenyl phosphite, and 35.5 parts of styrene.

[0027] The preparation method of the unsaturated polyester resin material containing potassium bromide composite accelerator comprises the following steps: (1) Diethylene glycol, maleic anhydride, phthalic anhydride, triphenyl phosphite, and hydroquinone are put into a reaction kettle, heated to 200 ± 5 °C, and kept at this temperature for reaction for 3 h. The acid value is 87.5 ± 2.5 mgKOH / g, and the cone-plate viscosity is 1.15 ± 0.05 P. Subsequently, water is removed under a vacuum of -0.09 MPa for 1 h. The cone-plate viscosity of the system is 5.5 ± 0.2 P, and the acid value is 30 ± 2 mgKOH / g. After purging with nitrogen, the temperature is lowered to 185 °C, hydroquinone is added and stirred evenly, then the temperature is further lowered to 155 °C, and styrene is added for dilution and stirred evenly to obtain unsaturated polyester resin. Among them, the mass ratio of hydroquinone added twice is 1:2, and the total mass fraction of hydroquinone added is 0.05 parts; (2) The unsaturated polyester resin and the composite accelerator are placed in a treatment kettle and stirred evenly. Subsequently, methyl ethyl ketone peroxide is added and stirred evenly, and then poured into a mold for curing at room temperature to form an unsaturated polyester resin material containing potassium bromide composite accelerator, and the gel time, the highest exothermic peak, the flexural strength, and the flexural modulus during the curing process are measured.

[0028] Example 3 The unsaturated polyester resin material containing potassium bromide composite accelerator includes the following raw materials in parts by mass: 150 parts of unsaturated polyester resin, 2 parts of composite accelerator (the mass ratio of cobalt octoate solution to potassium bromide is 0.5:1), and 0.8 part of methyl ethyl ketone peroxide; The unsaturated polyester resin is composed of the following raw materials in parts by mass: 56.0 parts of diethylene glycol, 27.0 parts of phthalic anhydride, 31.0 parts of maleic anhydride, 0.05 part of hydroquinone, 0.15 part of triphenyl phosphite, and 35.5 parts of styrene.

[0029] The preparation method of the unsaturated polyester resin material containing potassium bromide composite accelerator includes the following steps: (1) Diethylene glycol, maleic anhydride, phthalic anhydride, triphenyl phosphite, and hydroquinone are put into a reaction kettle, heated to 200±5°C, and kept for reaction for 3 h. The acid value is 87.5±2.5 mgKOH / g, and the cone-plate viscosity is 1.15±0.05 P. Subsequently, water is removed under a vacuum of -0.09 MPa for 1 h. The cone-plate viscosity of the system is 5.5±0.2 P, and the acid value is 30±2 mgKOH / g. After purging with nitrogen, the temperature is lowered to 185°C, hydroquinone is added and stirred evenly, the temperature is further lowered to 155°C, and styrene is added for dilution and stirred evenly to obtain unsaturated polyester resin; among them, the mass ratio of hydroquinone added twice is 1:2, and the total mass fraction of hydroquinone added is 0.05 part; (2) The unsaturated polyester resin and the composite accelerator are placed in a treatment kettle and stirred evenly. Subsequently, methyl ethyl ketone peroxide is added and stirred evenly, and then poured into a mold for curing at room temperature to form an unsaturated polyester resin material containing potassium bromide composite accelerator, and the gel time, the highest exothermic peak, and the flexural strength and flexural modulus during its curing process are detected.

[0030] Comparative Example 1 This comparative example is the same as Example 1, except that in the unsaturated polyester resin material containing potassium bromide composite accelerator, the composite accelerator is only 0.7 part of cobalt octoate solution, and the other components and the preparation process are the same as those in Example 1.

[0031] The performance of the unsaturated polyester resin materials containing potassium bromide composite accelerator prepared in Examples 1-3 and Comparative Example 1 was tested. The highest exothermic peak temperature, gel time, and time to peak during the curing process are shown in Table 1. The gel time was detected according to GB / T7193-2008. The detection process of the highest exothermic peak temperature and time to peak is as follows: after the unsaturated polyester resin cures to the gel state, a thermocouple or other temperature sensor is used to monitor the internal temperature change during the curing of the unsaturated polyester resin in real time, and the change of temperature with time during this process is recorded, that is, the highest exothermic peak and time to peak (the sum including the gel time) during the curing process of the unsaturated polyester resin are obtained, seeFigures 1 - 4 ; The flexural strength and flexural modulus were detected according to GB / T 2567-2008, and the test results are shown in Table 2.

[0032] Table 1 Gel time, peak time, and maximum exothermic peak temperature of the products of Examples 1-3 and Comparative Example 1

[0033] Table 2 Flexural strength and flexural modulus of the products of Examples 1-3 and Comparative Example 1

[0034] From Table 1 and Figures 1 - 4 It can be seen that by adding potassium bromide to the cobalt octoate accelerator, the gel time of the unsaturated polyester resin can be significantly shortened, and the exothermic peak temperature is slightly increased. In a low-temperature environment (such as winter construction), the high exotherm can compensate for the insufficient ambient temperature, ensure the normal curing of the unsaturated polyester resin, help accumulate internal heat, reduce the risk of incomplete curing, and also form a more compact crosslinked network, thereby improving the mechanical strength of the resin.

[0035] From Table 2, it can be seen that after using the composite accelerator containing potassium bromide, both the flexural strength and flexural modulus of the product have increased. This result indicates that the introduction of potassium bromide can catalyze the isomerization crosslinking of the unsaturated polyester resin, form a more compact crosslinked network, improve the mechanical strength of the product, enhance the impact resistance of the product, increase the structural load-bearing capacity, reduce warping caused by environmental stress, and optimize the dimensional stability.

[0036] In addition, since cobalt ions are expensive, directly using commercially available cobalt octoate as an accelerator to produce unsaturated polyester resin materials has a relatively high production cost. After using the composite accelerator of the present invention, on the basis of shortening the gel time, the amount of cobalt octoate used is reduced, and the production cost is reduced.

[0037] Generally speaking, for the unsaturated polyester resin material with the potassium bromide-containing composite accelerator of the present invention, by using a composite accelerator system composed of cobalt octoate and potassium bromide, the curing process of the unsaturated polyester resin is accelerated, the gel time is shortened, and the curing efficiency of the unsaturated polyester resin is improved; in addition, potassium bromide can catalyze the isomerization crosslinking of the unsaturated polyester resin, enabling the product to form a more compact crosslinked network, thereby improving the flexural strength and flexural modulus of the product, ensuring the mechanical strength of the product, and enhancing the impact resistance of the product.

Claims

1. An unsaturated polyester resin material containing a potassium bromide composite accelerator, characterized in that: The method comprises the following raw materials in parts by weight: 80-150 parts of unsaturated polyester resin, 0.6-2 parts of composite accelerator, and 0.8-3.0 parts of initiator; The unsaturated polyester resin is composed of the following raw materials in parts by weight: 50-80 parts of diol, 20-35 parts of saturated dibasic acid, 30-40 parts of unsaturated dibasic acid, 0.01-1 parts of polymerization inhibitor, 0.1-1 parts of antioxidant, and 30-50 parts of crosslinking agent; The composite accelerator is composed of an organic cobalt salt solution and potassium bromide, and the mass ratio of the organic cobalt salt solution to potassium bromide is (0.5-3):

1.

2. The unsaturated polyester resin material containing potassium bromide composite accelerator according to claim 1, characterized in that: The organic cobalt salt in the organic cobalt salt solution is one or both of cobalt isooctanoate and cobalt cyclohexaneate.

3. The unsaturated polyester resin material containing potassium bromide composite accelerator according to claim 1, characterized in that: The initiator is one or both of methyl ethyl ketone peroxide and cyclohexanone peroxide.

4. The unsaturated polyester resin material containing potassium bromide composite accelerator according to claim 1, characterized in that: The diol is one or more of diethylene glycol, ethylene glycol and propylene glycol.

5. The unsaturated polyester resin material containing potassium bromide composite accelerator according to claim 1, characterized in that: The saturated dibasic acid is one or more of phthalic anhydride, isophthalic acid, terephthalic acid, and adipic acid, and the unsaturated dibasic acid is one of maleic anhydride and fumaric acid.

6. The unsaturated polyester resin material containing potassium bromide composite accelerator according to claim 1, characterized in that: The antioxidant is one or two of triphenyl phosphite and 2,6-di-tert-butyl-p-methylphenol.

7. The unsaturated polyester resin material containing potassium bromide composite accelerator according to claim 1, characterized in that: The polymerization inhibitor is hydroquinone, and the cross-linking agent is styrene.

8. A method for preparing an unsaturated polyester resin material containing a potassium bromide composite accelerator according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) Add diol, saturated dibasic acid, unsaturated dibasic acid, antioxidant and polymerization inhibitor into a reaction kettle, raise the temperature to 160-210°C, keep the temperature for reaction for 1-6 hours until the acid value reaches 50-150 mgKOH / g and the cone-plate viscosity reaches 1.0-1.5P, then remove water under vacuum pressure at -0.06MPa~-0.1MPa for 1-5 hours until the cone-plate viscosity reaches 2.0-20P and the acid value reaches 20-45 mgKOH / g, evacuate nitrogen and cool down, add polymerization inhibitor and crosslinking agent to dilute, stir evenly, and obtain unsaturated polyester resin; (2) placing an unsaturated polyester resin, a composite accelerator and an initiator in a processing kettle, stirring them evenly, pouring them into a mold and curing them at room temperature to obtain an unsaturated polyester resin material containing a potassium bromide composite accelerator.

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