Unsaturated polyester resin material containing potassium bromide composite accelerator and preparation method thereof

Abstract

The present invention belongs to the technical field of unsaturated polyester resin materials, and specifically relates to an unsaturated polyester resin material containing a potassium bromide composite accelerator and a preparation method thereof. The unsaturated polyester resin material containing a potassium bromide composite accelerator comprises the following raw materials: an unsaturated polyester resin, a composite accelerator, and an initiator; the unsaturated polyester resin is composed of the following raw materials: a diol, a saturated dibasic acid, an unsaturated dibasic acid, an inhibitor, an antioxidant, and styrene. The unsaturated polyester resin material containing a potassium bromide composite accelerator of the present invention uses a composite accelerator to catalyze the isomerization and cross-linking of the unsaturated polyester resin, thereby increasing the curing speed of the unsaturated polyester resin, ensuring production efficiency, and reducing production costs; the product prepared using the composite accelerator has improved flexural strength and flexural modulus, and the impact resistance of the product is enhanced; the present invention also provides a preparation method thereof, and the preparation process is simple.

Description

Technical Field

[0001] 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 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 performance and economy, unsaturated polyester resin occupies an important position in both traditional industries and emerging fields. The resin curing speed 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, it will cause a series of systemic problems: first, the material is in a low-viscosity fluid state for a long time, making it difficult for internal bubbles to be effectively discharged through natural degassing or vacuum treatment. At the same time, the reinforcing materials (such as glass fiber and carbon fiber) settle and stratify due to the lack of timely curing constraints, resulting in uneven distribution of local reinforcement phases; second, the uncured resin continues to flow under the action of gravity and surface tension, causing product dimensions to deviate from the design tolerance and defects such as flow marks and depressions to appear on the surface; insufficient curing will also reduce the cross-linking density of the material, showing characteristics of increased brittleness and deterioration of mechanical properties; in addition, the extension of the open time significantly increases the environmental sensitivity of the production process, and pollutants such as dust and moisture can easily invade the surface of the material, causing quality problems such as sagging and color spots, increasing energy consumption and working hours, and raising production costs.

[0004] CN114249864A discloses an unsaturated polyester resin accelerator, a preparation method thereof, and an application thereof. By using methanol, copper acetate, cobalt isooctanoate, and water as accelerators, the gelation 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 unsaturated polyester resin accelerator, which introduces copper naphthenate or copper isooctanoate into a pure cobalt isooctanoate curing system. The cobalt isooctanoate is used to accelerate the curing process of the resin, shorten the gelation time, and improve the efficiency of the resin curing. The copper naphthenate or copper isooctanoate reduces the exothermic peak temperature of the unsaturated polyester resin and suppresses the heat release of the unsaturated polyester resin. The use of the two together can shorten the gelation time of the resin. , reducing the exothermic peak temperature during the resin curing process, effectively preventing problems such as cracking and deformation during the curing process of thick samples; however, the above patents all use copper-containing organic matter and cobalt isooctanoate solution to compound. Although the cobalt ion content is reduced, the copper organic matter will change color (such as oxidized and blackened) under light or humid and hot environment, affecting the appearance of the product. In order to inhibit side effects (such as discoloration and agglomeration), it may be necessary to use antioxidants, UV stabilizers and other additives to increase the complexity of the formula. In addition, copper ions will interfere with the cross-linked network structure, hinder the normal cross-linking reaction, and cause the cross-linked network structure to be uneven or incomplete, which in turn leads to a decrease in the mechanical strength of the resin after curing. 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 that can significantly improve the curing speed of the unsaturated polyester resin without negatively affecting product performance by designing its components. Summary of the Invention

[0006] The present invention aims to overcome the defects of the prior art and provide an unsaturated polyester resin material containing a potassium bromide composite accelerator. By using the composite accelerator, the unsaturated polyester resin is catalyzed to undergo isomerization and cross-linking, thereby increasing the curing speed of the unsaturated polyester resin, ensuring production efficiency, and reducing production costs. Products prepared using the composite accelerator have improved flexural strength and flexural modulus, and enhanced impact resistance. The present invention also provides a preparation method thereof, which is simple in preparation process.

[0007] The unsaturated polyester resin material containing a 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 a composite accelerator, and 0.8-3.0 parts of an initiator. The unsaturated polyester resin is composed of the following raw materials in parts by mass: 50-80 parts of a diol, 20-35 parts of a saturated dibasic acid, 30-40 parts of an unsaturated dibasic acid, 0.01-1 part of a polymerization inhibitor, 0.1-1 part of an antioxidant, and 30-50 parts of a 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 both of cobalt isooctanoate and cobalt naphthenate, preferably the cobalt isooctanoate solution commercially available from Tianjin Miaoyang Chemical Co., Ltd., wherein the cobalt ion concentration in the cobalt isooctanoate solution is 8 wt.%. The main components of the commercially available cobalt isooctanoate solution are cobalt isooctanoate and a solvent, and the solvent is ethanol.

[0009] The initiator is one or both 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 both of triphenyl phosphite and 2,6-di-tert-butyl-p-methylphenol (antioxidant 264), preferably triphenyl phosphite.

[0013] The polymerization inhibitor is hydroquinone, and the cross-linking agent is styrene.

[0014] The method for preparing the unsaturated polyester resin material containing potassium bromide composite accelerator comprises the following steps:

[0015] (1) Add diol, saturated dibasic acid, unsaturated dibasic acid, antioxidant and polymerization inhibitor into a reactor, heat to 160-210°C, keep warm and react for 1-6 hours until the acid value reaches 50-150 mgKOH / g and the cone and plate viscosity reaches 1.0-1.5P, then remove water under -0.06MPa~-0.1MPa vacuum pressure for 1-5 hours until the cone and plate viscosity reaches 2.0-20P and the acid value reaches 20-45 mgKOH / g, evacuate nitrogen and cool to 185°C, add polymerization inhibitor and stir evenly, continue to cool to 155°C, add crosslinking agent to dilute, stir evenly to obtain unsaturated polyester resin; wherein the mass ratio of polymerization inhibitor added twice is 1:2;

[0016] (2) The unsaturated polyester resin, the composite accelerator and the initiator are placed in a treatment kettle, stirred evenly, poured into a mold and cured at room temperature to obtain an unsaturated polyester resin material containing a potassium bromide composite accelerator.

[0017] Preferably, the unsaturated polyester resin material containing potassium bromide composite accelerator needs to be added with a certain proportion of inorganic filler during preparation to improve its performance in the application of construction and decoration fields (such as countertops and basins, floors and walls, exterior wall decoration, etc.) and industrial equipment (including anti-corrosion equipment, wear-resistant parts, etc.).

[0018] The unsaturated polyester resin material containing a potassium bromide composite accelerator of the present invention introduces inorganic potassium bromide on the basis of a traditional organic cobalt salt. Potassium bromide itself has relatively weak initiating activity, but in the presence of cobalt ions, the potassium ions can synergistically interact with the cobalt ions to generate free radical reaction interference, change electron distribution, and make the O-O bond in the peroxide more likely to break, thereby accelerating the decomposition speed of the initiator and indirectly promoting the reaction. At the same time, bromine has a strong electron-withdrawing ability, thereby making the double bond electron pair rearrangement reaction more likely to proceed, further catalyzing the isomerization and crosslinking of the unsaturated polyester resin. The inorganic potassium bromide has high light transmittance and chemical inertness, is more stable, and is not prone to high-temperature decomposition reaction.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) The unsaturated polyester resin material containing potassium bromide composite accelerator of the present invention introduces potassium bromide and organic cobalt salt as composite accelerators. The presence of potassium ions can produce free radical reaction interference, change the decomposition mechanism of peroxide, and accelerate the decomposition rate of the initiator. In addition, potassium bromide can catalyze the isomerization cross-linking of the unsaturated polyester resin, further change the curing reaction rate of the unsaturated polyester resin, and significantly shorten the curing time.

[0021] (2) Compared with the traditional curing system, the unsaturated polyester resin material containing potassium bromide composite accelerator of the present invention has a low cobalt ion concentration and uses potassium bromide to reduce the probability of side reactions during the curing and cross-linking process of the unsaturated polyester resin, thereby ensuring the mechanical strength of the unsaturated polyester resin material.

[0022] (3) The preparation method of the unsaturated polyester resin material containing potassium bromide composite accelerator of the present invention has a simple preparation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is the highest exothermic peak during the curing process of the unsaturated polyester resin in Example 1 of the present invention;

[0024] Figure 2is the highest exothermic peak during the curing process of the unsaturated polyester resin in Example 2 of the present invention;

[0025] Figure 3 is the highest exothermic peak during the curing process of the unsaturated polyester resin in Example 3 of the present invention;

[0026] Figure 4 It is the highest exothermic peak during the curing process of the unsaturated polyester resin in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0027] The present invention will be further described below with reference to the following examples and comparative examples. Unless otherwise specified, the raw materials used in the examples and comparative examples are all conventional commercially available raw materials, and the process methods used in the examples and comparative examples are all conventional methods in the art unless otherwise specified.

[0028] The raw materials used in the embodiments and comparative examples are described as follows:

[0029] Cobalt 2-ethylhexanoate solution: The main components are cobalt 2-ethylhexanoate and ethanol, and the cobalt ion concentration in the solution is 8 wt.%, which was purchased from Tianjin Miaoyang Chemical Co., Ltd.

[0030] The unsaturated polyester resin used in the examples and comparative examples is described as follows: the unsaturated polyester resin is composed of the following raw materials in parts by weight: 56.0 parts of diethylene glycol, 27.0 parts of phthalic anhydride, 31.0 parts of maleic anhydride, 0.05 parts of hydroquinone, 0.15 parts of triphenyl phosphite, and 35.5 parts of styrene; the specific preparation process of the unsaturated polyester resin is as follows: the above-mentioned parts by weight of diethylene glycol, maleic anhydride, phthalic anhydride, triphenyl phosphite, and hydroquinone are added into a reactor, the temperature is raised to 200±5°C, the reaction is kept warm for 3 hours, and the acid value is determined. The system was 87.5±2.5mgKOH / g and had a cone and plate viscosity of 1.15±0.05P. Subsequently, water was removed under vacuum at -0.09MPa for 1h, and the cone and plate viscosity of the system was 5.5±0.2P, and the acid value was 30±2mgKOH / g. After the nitrogen was evacuated, the temperature was lowered to 185°C, hydroquinone was added and stirred evenly, and the temperature was further lowered to 155°C, styrene was added to dilute, and stirred evenly to obtain an unsaturated polyester resin; wherein, the mass ratio of the hydroquinone added twice was 1:2, and the mass fraction of the hydroquinone added in total was 0.05 parts.

[0031] Example 1

[0032] The unsaturated polyester resin material containing potassium bromide composite accelerator comprises the following raw materials in parts by mass: 100 parts of unsaturated polyester resin, 0.7 parts of composite accelerator (the mass ratio of cobalt isooctanoate solution to potassium bromide is 1:1), and 1.0 parts of methyl ethyl ketone peroxide;

[0033] 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 parts of hydroquinone, 0.15 parts of triphenyl phosphite, and 35.5 parts of styrene.

[0034] The method for preparing the unsaturated polyester resin material containing potassium bromide composite accelerator comprises the following steps:

[0035] (1) Diethylene glycol, maleic anhydride, phthalic anhydride, triphenyl phosphite and hydroquinone were put into a reactor, heated to 200±5℃, and kept warm for 3h. The acid value was 87.5±2.5mgKOH / g and the cone and plate viscosity was 1.15±0.05P. Subsequently, water was removed under -0.09MPa vacuum pressure for 1h. The cone and plate viscosity of the system was 5.5±0.2P and the acid value was 30±2mgKOH / g. After nitrogen was vented, the temperature was lowered to 185℃, hydroquinone was added and stirred evenly, and the temperature was further lowered to 155℃. Styrene was added to dilute and stirred evenly to obtain an unsaturated polyester resin. The mass ratio of the hydroquinone added twice was 1:2, and the mass fraction of the hydroquinone added was 0.05 parts in total.

[0036] (2) The unsaturated polyester resin and the composite accelerator were placed in a treatment kettle and stirred evenly. Subsequently, methyl ethyl ketone peroxide was added and stirred evenly. The mixture was poured into a mold and cured at room temperature to obtain an unsaturated polyester resin material containing a potassium bromide composite accelerator. The gelation time, maximum exothermic peak, flexural strength and flexural modulus during the curing process were tested.

[0037] Example 2

[0038] The unsaturated polyester resin material containing potassium bromide composite accelerator comprises the following raw materials in parts by mass: 80 parts of unsaturated polyester resin, 0.6 parts of composite accelerator (the mass ratio of cobalt isooctanoate solution to potassium bromide is 3:1), and 3.0 parts of methyl ethyl ketone peroxide;

[0039] 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 parts of hydroquinone, 0.15 parts of triphenyl phosphite, and 35.5 parts of styrene.

[0040] The method for preparing the unsaturated polyester resin material containing potassium bromide composite accelerator comprises the following steps:

[0041] (1) Diethylene glycol, maleic anhydride, phthalic anhydride, triphenyl phosphite and hydroquinone were put into a reactor, heated to 200±5℃, and kept warm for 3h. The acid value was 87.5±2.5mgKOH / g and the cone and plate viscosity was 1.15±0.05P. Subsequently, water was removed under -0.09MPa vacuum pressure for 1h. The cone and plate viscosity of the system was 5.5±0.2P and the acid value was 30±2mgKOH / g. After nitrogen was vented, the temperature was lowered to 185℃, hydroquinone was added and stirred evenly, and the temperature was further lowered to 155℃. Styrene was added to dilute and stirred evenly to obtain an unsaturated polyester resin. The mass ratio of the hydroquinone added twice was 1:2, and the mass fraction of the hydroquinone added was 0.05 parts in total.

[0042] (2) The unsaturated polyester resin and the composite accelerator were placed in a treatment kettle and stirred evenly. Subsequently, methyl ethyl ketone peroxide was added and stirred evenly. The mixture was poured into a mold and cured at room temperature to obtain an unsaturated polyester resin material containing a potassium bromide composite accelerator. The gelation time, maximum exothermic peak, flexural strength and flexural modulus during the curing process were tested.

[0043] Example 3

[0044] The unsaturated polyester resin material containing potassium bromide composite accelerator comprises the following raw materials in parts by mass: 150 parts of unsaturated polyester resin, 2 parts of composite accelerator (the mass ratio of cobalt isooctanoate solution to potassium bromide is 0.5:1), and 0.8 parts of methyl ethyl ketone peroxide;

[0045] 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 parts of hydroquinone, 0.15 parts of triphenyl phosphite, and 35.5 parts of styrene.

[0046] The method for preparing the unsaturated polyester resin material containing potassium bromide composite accelerator comprises the following steps:

[0047] (1) Diethylene glycol, maleic anhydride, phthalic anhydride, triphenyl phosphite and hydroquinone were put into a reactor, heated to 200±5℃, and kept warm for 3h. The acid value was 87.5±2.5mgKOH / g and the cone and plate viscosity was 1.15±0.05P. Subsequently, water was removed under -0.09MPa vacuum pressure for 1h. The cone and plate viscosity of the system was 5.5±0.2P and the acid value was 30±2mgKOH / g. After nitrogen was vented, the temperature was lowered to 185℃, hydroquinone was added and stirred evenly, and the temperature was further lowered to 155℃. Styrene was added to dilute and stirred evenly to obtain an unsaturated polyester resin. The mass ratio of the hydroquinone added twice was 1:2, and the mass fraction of the hydroquinone added was 0.05 parts in total.

[0048] (2) The unsaturated polyester resin and the composite accelerator were placed in a treatment kettle and stirred evenly. Subsequently, methyl ethyl ketone peroxide was added and stirred evenly. The mixture was poured into a mold and cured at room temperature to obtain an unsaturated polyester resin material containing a potassium bromide composite accelerator. The gelation time, maximum exothermic peak, flexural strength and flexural modulus during the curing process were tested.

[0049] Comparative Example 1

[0050] This comparative example is the same as Example 1, except that, in the unsaturated polyester resin material containing the potassium bromide composite accelerator, the composite accelerator is only 0.7 parts of cobalt isooctanoate solution, and the remaining components and preparation process are the same as those in Example 1.

[0051] 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 maximum exothermic peak temperature, gel time, and peak time during the curing process are shown in Table 1. The gel time was tested in accordance with GB / T7193-2008. The testing process of the maximum exothermic peak temperature and peak time is as follows: after the unsaturated polyester resin is cured and reaches a gel state, a thermocouple or other temperature sensor is used to monitor the temperature change inside the unsaturated polyester resin during curing in real time, and the temperature change over time during the process is recorded, so as to obtain the maximum exothermic peak and peak time (including the total of the gel time) during the curing process of the unsaturated polyester resin, see Table 1. Figures 1-4 ; The flexural strength and flexural modulus were tested according to GB / T2567-2008. The test results are shown in Table 2.

[0052] Table 1 Gel time, peak time, and maximum exothermic peak temperature of the products of Examples 1-3 and Comparative Example 1

[0053]

[0054] Table 2 Flexural strength and flexural modulus of the products of Examples 1-3 and Comparative Example 1

[0055]

[0056] Through Table 1 and Figures 1-4 It can be seen that by adding potassium bromide to the cobalt 2-ethylhexanoate accelerator, the gel time of the unsaturated polyester resin can be greatly 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 internal heat accumulation, reduce the risk of incomplete curing, and form a tighter cross-linking network, thereby improving the mechanical strength of the resin.

[0057] As can be seen from Table 2, the flexural strength and flexural modulus of the product are improved after the composite accelerator containing potassium bromide is used. This result shows that the introduction of potassium bromide can catalyze the isomerization and cross-linking of the unsaturated polyester resin to form a tighter cross-linking network, thereby improving the mechanical strength of the product, enhancing the impact resistance of the product, improving the structural bearing capacity, reducing the warping caused by environmental stress, and optimizing the dimensional stability.

[0058] In addition, due to the high price of cobalt ions, the production cost of unsaturated polyester resin materials directly using commercially available cobalt isooctanoate as an accelerator is relatively high. After adopting the composite accelerator of the present invention, the gel time is shortened, the amount of cobalt isooctanoate used is reduced, and the production cost is reduced.

[0059] In summary, the unsaturated polyester resin material containing a potassium bromide composite accelerator of the present invention accelerates the curing process of the unsaturated polyester resin, shortens the gel time, and improves the curing efficiency of the unsaturated polyester resin by adopting a composite accelerator system composed of cobalt isooctanoate and potassium bromide. In addition, potassium bromide can catalyze the isomerization and cross-linking of the unsaturated polyester resin, so that the product forms a tighter cross-linked 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 mass: 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 a cobalt isooctanoate solution and potassium bromide, wherein the cobalt ion concentration in the cobalt isooctanoate solution is 8 wt.%, and the mass ratio of the cobalt isooctanoate solution to potassium bromide is (0.5-3):1; The method for preparing the unsaturated polyester resin material containing potassium bromide composite accelerator comprises the following steps: (1) Add diol, saturated dibasic acid, unsaturated dibasic acid, antioxidant and polymerization inhibitor into a reactor, heat to 160-210°C, keep warm and react for 1-6 hours until the acid value reaches 50-150 mgKOH / g and the cone and plate viscosity reaches 1.0-1.5P, then remove water under -0.06MPa~-0.1MPa vacuum pressure for 1-5 hours until the cone and plate viscosity reaches 2.0-20P and the acid value reaches 20-45 mgKOH / g, evacuate nitrogen and cool to 185°C, add polymerization inhibitor and stir evenly, continue to cool to 155°C, add crosslinking agent to dilute, stir evenly to obtain unsaturated polyester resin; wherein the mass ratio of polymerization inhibitor added twice is 1:2; (2) The unsaturated polyester resin, the composite accelerator and the initiator are placed in a treatment kettle, stirred evenly, poured into a mold and cured at room temperature to obtain an unsaturated polyester resin material containing a potassium bromide composite accelerator.

2. 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.

3. 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.

4. 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.

5. 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.

6. 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.

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