An unsaturated polyester resin for a daylighting tile and a method for preparing the same

Abstract

The application relates to a kind of unsaturated polyester resin for daylighting tile and a preparation method thereof, and belongs to the technical field of polyester resin.The unsaturated polyester resin is composed of the following components: DCPD, EG, PG, glycerol, maleic anhydride, phthalic anhydride, antioxidant, polymerization inhibitor, defoaming agent, stabilizer, diluent and water;the weight ratio of PG to glycerol is 1.00-1.36:1;the weight ratio of maleic anhydride, DCPD and phthalic anhydride is 1.70-1.80:0.85-1.00:1;the purity of DCPD is greater than or equal to 75wt%, and the color number is less than or equal to 50Hazen;the steps are as follows: 1) adding water, EG, maleic anhydride and antioxidant, heating, and then adding DCPD;2) adding EG, PG, glycerol, maleic anhydride, phthalic anhydride and antioxidant, and dehydrating;3) adding polymerization inhibitor, stabilizer and diluent after cooling, and adding defoaming agent after cooling;mixing uniformly to obtain the resin.The unsaturated polyester resin for daylighting tile has light color, high mechanical strength and can meet the requirements of daylighting tile.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of polyester resin, and particularly relates to an unsaturated polyester resin for light collecting tiles and a preparation method thereof. BACKGROUND

[0002] FRP (fiber reinforced polymer) light collecting tiles are widely used as core lighting materials in scenes such as industrial plants, agricultural greenhouses and public buildings, and have the characteristics of corrosion resistance, low cost and excellent light transmittance. Dicyclopentadiene type unsaturated polyester resin has become an important raw material for FRP light collecting tiles due to its temperature resistance and cost advantage, but the existing dicyclic resin for light collecting tiles has the key defects of deep color and insufficient mechanical strength, which restricts its application in high requirement scenes.

[0003] In the agricultural greenhouse scene, the existing dicyclic resin has deep color, which leads to insufficient light transmittance, and cannot provide sufficient and uniform light for vegetable seedling and crop photosynthesis, directly affecting the growth cycle and yield of crops; at the same time, the mechanical strength is low, and it is easy to be damaged when facing natural impact such as hail and snow, increasing the maintenance cost of the greenhouse. In the industrial plant, the plant span is large and the roof stress is complex, and the light collecting tile made of resin with low mechanical strength is easy to crack due to installation collision and external load, and the deep color will reduce the utilization rate of natural light inside the plant, increasing the energy consumption of artificial lighting; when used outdoors for a long time, the insufficient mechanical strength will also cause the light collecting tile to deform and warp under the alternating action of day and night temperature difference, affecting the sealing property of the roof. In public buildings, the light collecting tile with deep color will affect the indoor lighting effect and space aesthetics, and the insufficient mechanical strength is difficult to adapt to the structure stress demand of large span roof, which has safety hazards. Compared with o-benzene type resin, dicyclic type resin has lower cost and better temperature resistance, but the above defects make it unable to meet the upgrading demand of the downstream market for "high quality and high cost performance" light collecting tile, so it is urgent to develop an unsaturated polyester resin for light collecting tile with light color and high mechanical strength. SUMMARY

[0004] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art and provide an unsaturated polyester resin for light collecting tiles and a preparation method thereof. The unsaturated polyester resin for light collecting tiles has light color, high mechanical strength and can meet the demand of light collecting tiles.

[0005] To achieve the above object, the present application provides an unsaturated polyester resin for daylighting tile, characterized in that it is composed of the following components in parts by weight: dicyclopentadiene 110.5-122 parts, ethylene glycol 128.0-133.2 parts, propylene glycol 36.0-40.8 parts, glycerol 30-36 parts, maleic anhydride 219.6-221.0 parts, phthalic anhydride 122-130 parts, antioxidant 0.5-0.7 parts, polymerization inhibitor 0.06-0.08 parts, antifoaming agent 0.6-0.8 parts, stabilizer 0.02-0.04 parts, diluent 333-335 parts and water 20.18-20.3 parts.

[0006] The weight ratio of propylene glycol to glycerol is 1.00-1.36:1; the weight ratio of maleic anhydride, dicyclopentadiene to phthalic anhydride is 1.70-1.80:0.85-1.00:1, which can avoid the resin color deepening caused by excessive dicyclopentadiene or the impurity interference caused by insufficient dicyclopentadiene, and meanwhile control the cost of raw materials. The purity of dicyclopentadiene is greater than or equal to 75 wt%, and the color number is less than or equal to 50 Hazen.

[0007] Preferably, the purity of dicyclopentadiene is 75-80 wt%, and the color number is 30-50 Hazen, preferably the purity and color number of dicyclopentadiene can reduce the cost on the premise of realizing the technical effects of the present application. The color number of dicyclopentadiene is tested according to GB / T3143-1982.

[0008] Preferably, the present application is composed of the following components in parts by weight: dicyclopentadiene 114.0-119.5 parts, ethylene glycol 129.0-130.6 parts, propylene glycol 37.8-40.0 parts, glycerol 32-35 parts, maleic anhydride 220.0-220.6 parts, phthalic anhydride 124-128 parts, antioxidant 0.55-0.65 parts, polymerization inhibitor 0.065-0.075 parts, antifoaming agent 0.65-0.75 parts, stabilizer 0.025-0.035 parts, diluent 333.1-334.0 parts and water 20.21-20.27 parts. The antioxidant is triphenyl phosphite; the antifoaming agent is methyl silicone oil; the stabilizer is copper naphthenate; and the diluent is styrene.

[0009] Dicyclopentadiene is abbreviated as DCPD, ethylene glycol is abbreviated as EG, propylene glycol is abbreviated as PG, maleic anhydride is abbreviated as maleic anhydride, phthalic anhydride is abbreviated as phthalic anhydride, and glycerol is also known as glycerol.

[0010] The molecular chain of the glycol-synthesized resin is short, and the flexibility and heat resistance of the resin are relatively low, but the reaction rate is fast, the curing speed is improved during curing, and the color is light, which is beneficial to reduce the product color; the propylene glycol can improve the wettability of the resin, promote the adhesion between the resin and the substrate, and enhance the resin and glass fiber infiltration, the resin synthesized by propylene glycol has low crystallinity, and the use of propylene glycol and ethylene glycol together can improve the compatibility of polyester and styrene, but excessive propylene glycol will cause the resin color to deepen and increase the cost. The density of glycerol is larger than that of the commonly used diols, when the density increases, the number of molecular groups, molecules and atoms per unit length increases, and the refractive index increases with the increase of density, and the refractive index reflects the light transmittance of the resin, the higher the refractive index, the higher the transparency of the light collecting tile, and the polyol crosslinking density is large, as a multifunctional alcohol, it can increase the crosslinking density of the resin molecular chain, make the resin structure more dense, improve the mechanical properties of the resin after curing, and have better heat resistance and weather resistance, but ethylene glycol and glycerol have symmetrical structure and high crystallinity, and excessive amount will cause the resin to be layered.

[0011] When the weight ratio of propylene glycol to glycerol is in the range of 1.0-1.36, and the amount of propylene glycol is 18-20% of the total alcohol, the resin synthesized under this ratio has light color and good compatibility with styrene. When the weight ratio of propylene glycol to glycerol exceeds the range of 1.0-1.36, i.e. excessive propylene glycol will cause the resin color to deepen to yellow; when the amount of propylene glycol is too small and the amount of propylene glycol and ethylene glycol is too large, the symmetrical structure will cause the resin to be layered. The optimized resin infiltration and toughness of propylene glycol, the crosslinking density, heat resistance and weather resistance of glycerol, and the balance between process performance and long-term stability are in the range of 1.0-1.36:1.

[0012] The use of dicyclopentadiene can improve the heat resistance, water resistance and corrosion resistance of the unsaturated polyester resin for light collecting tile, but dicyclopentadiene has a great influence on the color of the resin, and the impurity content of low content dicyclopentadiene will affect the reaction rate and index control, and then affect the performance of the resin, which will affect the transparency of the light collecting tile; high content of dicyclopentadiene has high cost, and the purity of dicyclopentadiene is greater than or equal to 75wt%, and the color number is less than or equal to 50Hazen from the economic and light collecting tile performance.

[0013] The weight ratio of maleic anhydride, dicyclopentadiene, and phthalic anhydride is 1.70–1.80:0.85–1.00:1. When the weight ratio of maleic anhydride to phthalic anhydride is constant, excess dicyclopentadiene not only affects the product color but also reduces reactivity due to the hydrolysis reaction between maleic anhydride and dicyclopentadiene, leading to slower gelation time and insufficient exothermic reaction. Conversely, insufficient dicyclopentadiene increases reactivity, accelerates gelation, and intensifies exothermic reaction. When the weight ratio of maleic anhydride to phthalic anhydride is less than 1.7, the reactivity and reaction rate decrease, resulting in a longer gelation time and post-curing time when the target acid value is reached. The reduced exothermic peak can lead to poor curing when manufacturing translucent tiles. Without changing other process conditions, this can cause the translucent tiles to soften, affecting the product's strength. When the weight ratio of maleic anhydride to phthalic anhydride is greater than 1.8, the reactivity increases, the reaction rate increases, the crosslinking density becomes too high, the gel time becomes faster, the post-curing time is shortened, and the exothermic peak increases. This can lead to fiber burning or fiber shedding when adding glass fiber to resin to make skylights, affecting the transparency of the skylights. Meanwhile, a weight ratio of maleic anhydride to phthalic anhydride of 1.7–1.8:1 avoids the "fiber burning / fiber shedding" problem caused by excessively high reactivity, or the "poor curing and softening of the product" problem caused by excessively low reactivity. Fiber burning is a defect caused by localized overheating of the resin, resulting in damage to the glass fiber; fiber shedding is a defect caused by insufficient resin wetting / uneven curing, resulting in the exposure of the glass fiber outline.

[0014] Preferably, the weight ratio of propylene glycol to glycerol is 1.08–1.25:1. This allows the unsaturated polyester resin used in skylights to have a lighter color. At this ratio, propylene glycol can fully improve the wettability of the unsaturated polyester resin to glass fibers, enabling the resin to tightly wrap the fibers and reduce interfacial defects. Simultaneously, the crosslinking density enhancement effect of glycerol is more stable.

[0015] Preferably, the weight ratio of maleic anhydride to phthalic anhydride is 1.72 to 1.77:1; this ratio ensures optimal reactivity, uniform curing process, and no local overheating or insufficient curing.

[0016] The polymerization inhibitor is at least one of hydroquinone and p-benzoquinone. The process of making the light-transmitting tile involves two stages of heating to improve the curing effect. The first stage requires a fast gelation speed, and the second stage has a higher temperature than the first stage. The two polymerization inhibitors work better when used together.

[0017] Preferably, the polymerization inhibitor is composed of hydroquinone and p-benzoquinone in a weight ratio of 1:0.5~1.1. This ratio allows for control of the resin's "storage stability" and "curing speed." During storage, the inhibitor effectively suppresses premature polymerization of double bonds; during molding, it does not excessively hinder the curing reaction, avoiding premature gelation due to insufficient polymerization inhibition or delayed curing due to excessive polymerization inhibition. At this ratio, the inhibitor itself is less prone to oxidation and discoloration, ensuring a uniform pale yellow final color for the resin, providing a stable additive basis for the light transmittance of the translucent tiles.

[0018] This invention also provides a method for preparing unsaturated polyester resin for light-transmitting tiles, comprising the following steps:

[0019] (1) Add water, ethylene glycol, maleic anhydride and antioxidant to the reaction vessel according to the weight parts, heat to 70-80℃, and after the reaction is exothermic, keep it at 115-125℃ for 28-32 min, then add dicyclopentadiene and keep it at 2.0-2.5 h;

[0020] (2) Add ethylene glycol, propylene glycol, glycerol, maleic anhydride, phthalic anhydride and antioxidant to the reaction vessel of step (1) according to the weight parts, heat to 145-150℃ and keep at the temperature for 0.5-1.0h, then heat to 175-185℃, and then heat to 195-200℃ at a rate of 12-14℃ / h and keep at the temperature for 1.5-2.0h; dehydrate until the acid value reaches 15-20mgKOH / g;

[0021] (3) Cool the product obtained in step (2) to 170-180°C and add the polymerization inhibitor according to the weight; cool to 110-120°C and add the stabilizer and diluent according to the weight; continue to cool to 50-60°C and add the defoamer; mix well to obtain unsaturated polyester resin for light-transmitting tiles.

[0022] Adding antioxidants in steps (1) and (2) is also to maximize the antioxidant effect and optimize the product color.

[0023] In step (1), the amount of ethylene glycol added accounts for 50% of the total amount of ethylene glycol added, and in step (2), the amount of ethylene glycol added accounts for 50% of the total amount of ethylene glycol added; in step (1), the amount of maleic anhydride added accounts for 50% of the total amount of maleic anhydride added, and in step (2), the amount of maleic anhydride added accounts for 50% of the total amount of maleic anhydride added; in step (1), the amount of antioxidant added accounts for 40% of the total amount of antioxidant added, and in step (2), the amount of antioxidant added accounts for 60% of the total amount of antioxidant added.

[0024] The specific operation of step (1) is to add water, ethylene glycol, maleic anhydride and antioxidant under nitrogen protection, raise the temperature to 70-80℃, and after the reaction is self-exothermic, control the temperature at 115-125℃ and keep it at 28-32 min. Then add dicyclopentadiene at a rate of 1.1-1.2 g / min. After the dicyclopentadiene is added, keep it at 2.0-2.5 h.

[0025] In step (1), the addition rate of dicyclopentadiene is 1.1–1.2 g / min. The color of the unsaturated polyester resin is mainly affected by dicyclopentadiene and maleic anhydride. Step (1) is a hydrolysis reaction. Maleic anhydride reacts with an equimolar amount of water after heating to generate maleic acid. This process is exothermic and can easily cause overheating, which in turn leads to a darker color in the unsaturated polyester resin. Therefore, it is necessary to keep the temperature at 115–125°C for a period of time until the system temperature stabilizes before proceeding with subsequent operations. In addition, dicyclopentadiene also releases heat when it participates in the reaction. To avoid a sudden temperature rise caused by direct addition, which would affect product performance and also lead to a darker color in the unsaturated polyester resin, it should be added dropwise to the reaction vessel at a rate of 1.1–1.2 g / min.

[0026] Propylene glycol accounts for 18-20% of the total alcohol weight; if the ratio of total alcohol to total acid is too high, the viscosity of the finished product will be low when the acid value reaches 15-20 mg KOH / g in step (2) of dehydration, and the mechanical properties of the unsaturated polyester resin will be reduced; if the ratio of total alcohol to total acid is too low, the viscosity of the finished product will be high when the acid value reaches 15-20 mg KOH / g in step (2) of dehydration, and more diluent needs to be added to achieve the same finished product viscosity, which will increase the cost, and the unsaturated polyester resin will be brittle, with increased hardness and decreased toughness.

[0027] Preferably, propylene glycol accounts for 18.7 to 19.9% ​​of the total alcohol weight. Propylene glycol is a key component for improving the compatibility between resin and diluent, which can avoid stratification caused by too low a proportion of propylene glycol, and ensure that the unsaturated polyester resin used for skylights is in a uniform liquid state, so that there is no local performance unevenness during subsequent molding.

[0028] Compared with the prior art, the beneficial effects of this invention are:

[0029] 1. This invention provides an unsaturated polyester resin for light-transmitting tiles that is light in color, has high mechanical strength, and meets the requirements of light-transmitting tiles. By adjusting the weight ratio of propylene glycol to glycerol to 1.0-1.36:1, propylene glycol improves the wettability of the resin and the substrate, preventing delamination, while glycerol increases the molecular crosslinking density, thus avoiding fluorescence defects caused by excessive glycerol. Dicyclopentadiene with a purity of ≥75wt% and a color number ≤50Hazen is selected, and the weight ratio of maleic anhydride, dicyclopentadiene, and phthalic anhydride is adjusted to 1.70-1.80:0.85-1.00:1. This avoids the yellowing of the resin caused by excessive dicyclopentadiene and achieves a balance between performance and cost. At the same time, it avoids the "burning / yarn showing" problem caused by excessively high reactivity, or the "poor curing and softening of the product" problem caused by excessively low reactivity.

[0030] 2. The present invention discloses a method for preparing unsaturated polyester resin for skylights. By controlling the reaction endpoint acid value to 15-20 mgKOH / g and using appropriate raw material ratios, the viscosity of the unsaturated polyester resin for skylights in the liquid state is stabilized at 200-210 mPa·s, the gel time is controlled at 4′18″-4′36″, the post-curing time is 5′20″-5′48″, and the exothermic peak is stabilized at 175-178℃. This parameter range ensures that the resin gelation speed is moderate and the curing reaction is uniform during the production process, thus significantly improving the stability and yield of skylights.

[0031] 3. This invention provides an unsaturated polyester resin for skylights. Through molecular structure optimization, the cured resin achieves mechanical strength, heat resistance, and light transmittance that meet the standards for skylight use and are superior to existing products. The resin casting has a tensile strength of 45–47 MPa, a flexural strength of 81–86 MPa, and an impact strength of 8.2–8.8 kJ / m², enabling it to withstand external impacts during installation and use. The high mechanical strength of the unsaturated polyester resin results in stronger skylights with longer product durability. The heat distortion temperature reaches 50.1–50.5℃, making it less prone to deformation in high-temperature outdoor environments. The refractive index of 1.5408–1.5425 ensures the light transmittance of the skylights. Detailed Implementation

[0032] Example 5 is the preferred embodiment of the present invention. The present invention will be further described below with reference to specific embodiments and comparative examples.

[0033] The chemical additives used in the embodiments and comparative examples of this invention are all commercially available, and the specific information is as follows:

[0034] Dicyclopentadiene: purchased from Shandong Haoman Chemical Sales Co., Ltd.;

[0035] Ethylene glycol: purchased from Zhonghe Anji Energy Technology Co., Ltd.;

[0036] Propylene glycol: purchased from Guangdong Hongjiu New Materials Co., Ltd.;

[0037] Glycerol, also known as glycerin: purchased from Jiangze International Trade Co., Ltd.;

[0038] maleic anhydride: purchased from Shandong Dechuan New Materials Co., Ltd.;

[0039] Phthalic anhydride: purchased from Hubei Nengtai Technology Co., Ltd.;

[0040] Triphenyl phosphite: purchased from Changhe Chemical New Materials (Jiangsu) Co., Ltd.;

[0041] Hydroquinone: Purchased from Changzhou Yurong Chemical Co., Ltd.;

[0042] p-Benzoquinone: purchased from Jinan Xichuan Chemical Technology Co., Ltd.;

[0043] Methyl silicone oil: purchased from Changzhou Polerma Composite Materials Co., Ltd.;

[0044] Copper naphthenate: purchased from Shanghai Taoyuan Cobalt Co., Ltd.;

[0045] Styrene: Purchased from Zhangjiagang Free Trade Zone Aolide International Trade Co., Ltd.;

[0046] Cobalt isooctanoate: purchased from Shanghai Taoyuan Cobalt Co., Ltd.;

[0047] Methyl ethyl ketone peroxide: purchased from Qingdao Feiyang Trading Co., Ltd.;

[0048] Abbe refractometer: Shanghai No. 5 Optical Instrument Factory.

[0049] Table 1. Raw material formulations for the embodiments (by weight).

[0050] .

[0051] Example 1

[0052] The preparation method in this embodiment adopts the following steps:

[0053] (1) Add water, ethylene glycol, maleic anhydride and antioxidant to the reaction vessel according to the weight parts. Under nitrogen protection, raise the temperature to 75°C. After the reaction is self-exothermic, control the temperature at 120°C and keep it for 30 min. Add dicyclopentadiene to the reaction vessel at a rate of 1.1 g / min. After the dicyclopentadiene is added, keep it at the temperature for 2.3 h. The antioxidant is triphenyl phosphite.

[0054] (2) Ethylene glycol, propylene glycol, glycerol, maleic anhydride, phthalic anhydride and antioxidant are added to the reaction vessel of step (1) according to the weight parts. The temperature is raised to 145℃ and kept at 1.0h. Then the temperature is raised to 175℃ and raised to 195℃ at a rate of 12℃ / h and kept at 175℃ for 2.0h. The dehydration is carried out until the acid value reaches 15mgKOH / g. The antioxidant is triphenyl phosphite.

[0055] (3) Cool the product obtained in step (2) to 175°C and add the polymerization inhibitor according to the weight; cool to 115°C and add the stabilizer and diluent according to the weight; continue to cool to 55°C and add the defoamer; the defoamer is methyl silicone oil, the stabilizer is copper naphthenate, and the diluent is styrene; the polymerization inhibitor is composed of hydroquinone and p-benzoquinone in a weight ratio of 1:1.1; mix well to obtain unsaturated polyester resin for light-transmitting tiles.

[0056] Example 2

[0057] The preparation method in this embodiment adopts the following steps:

[0058] (1) Add water, ethylene glycol, maleic anhydride and antioxidant to the reaction vessel according to the weight parts. Under nitrogen protection, raise the temperature to 75°C. After the reaction is self-exothermic, control the temperature at 120°C and keep it for 30 min. Add dicyclopentadiene to the reaction vessel at a rate of 1.1 g / min. After the dicyclopentadiene is added, keep it at the temperature for 2.3 h. The antioxidant is triphenyl phosphite.

[0059] (2) Add ethylene glycol, propylene glycol, glycerol, maleic anhydride, phthalic anhydride and antioxidant to the reaction vessel of step (1) according to the weight parts; heat to 150℃ and keep warm for 0.5h, then heat to 185℃, and heat to 200℃ at a rate of 14℃ / h and keep warm for 2.0h; dehydrate until the acid value reaches 20mgKOH / g; the antioxidant is triphenyl phosphite;

[0060] (3) Cool the product obtained in step (2) to 175°C and add the polymerization inhibitor according to the weight; cool to 115°C and add the stabilizer and diluent according to the weight; continue to cool to 55°C and add the defoamer; the defoamer is methyl silicone oil, the stabilizer is copper naphthenate, and the diluent is styrene; the polymerization inhibitor is composed of hydroquinone and p-benzoquinone in a weight ratio of 1:0.5; mix well to obtain unsaturated polyester resin for light-transmitting tiles.

[0061] Example 3

[0062] The preparation method in this embodiment adopts the following steps:

[0063] (1) Add water, ethylene glycol, maleic anhydride and antioxidant to the reaction vessel according to the weight parts. Under nitrogen protection, raise the temperature to 75°C. After the reaction is self-exothermic, control the temperature at 120°C and keep it for 30 min. Add dicyclopentadiene to the reaction vessel at a rate of 1.1 g / min. After the dicyclopentadiene is added, keep it at the temperature for 2.3 h. The antioxidant is triphenyl phosphite.

[0064] (2) Ethylene glycol, propylene glycol, glycerol, maleic anhydride, phthalic anhydride and antioxidant are added to the reaction vessel of step (1) according to the weight parts; the temperature is raised to 147℃ and kept at 0.7h, then raised to 180℃, and raised to 197℃ at a rate of 13℃ / h and kept at 197℃ for 1.8h; dehydrated until the acid value reaches 17mgKOH / g; the antioxidant is triphenyl phosphite;

[0065] (3) Cool the product obtained in step (2) to 175°C and add the polymerization inhibitor according to the weight; cool to 115°C and add the stabilizer and diluent according to the weight; continue to cool to 55°C and add the defoamer; the defoamer is methyl silicone oil, the stabilizer is copper naphthenate, and the diluent is styrene; the polymerization inhibitor is composed of hydroquinone and p-benzoquinone in a weight ratio of 1:1; mix well to obtain unsaturated polyester resin for light-transmitting tiles.

[0066] Example 4

[0067] The preparation method in this embodiment adopts the following steps:

[0068] (1) Add water, ethylene glycol, maleic anhydride and antioxidant to the reaction vessel according to the weight parts. Under nitrogen protection, raise the temperature to 75°C. After the reaction is self-exothermic, control the temperature at 120°C and keep it for 30 min. Add dicyclopentadiene to the reaction vessel at a rate of 1.1 g / min. After the dicyclopentadiene is added, keep it at the temperature for 2.3 h. The antioxidant is triphenyl phosphite.

[0069] (2) Ethylene glycol, propylene glycol, glycerol, maleic anhydride, phthalic anhydride and antioxidant are added to the reaction vessel of step (1) according to the weight parts; the temperature is raised to 147℃ and kept at 0.7h, then raised to 180℃, and raised to 197℃ at a rate of 13℃ / h and kept at 197℃ for 1.8h; dehydrated until the acid value reaches 17mgKOH / g; the antioxidant is triphenyl phosphite;

[0070] (3) Cool the product obtained in step (2) to 175°C and add the polymerization inhibitor according to the weight; cool to 115°C and add the stabilizer and diluent according to the weight; continue to cool to 55°C and add the defoamer; the defoamer is methyl silicone oil, the stabilizer is copper naphthenate, and the diluent is styrene; the polymerization inhibitor is composed of hydroquinone and p-benzoquinone in a weight ratio of 1:1; mix well to obtain unsaturated polyester resin for light-transmitting tiles.

[0071] Example 5

[0072] The preparation method in this embodiment adopts the following steps:

[0073] (1) Add water, ethylene glycol, maleic anhydride and antioxidant to the reaction vessel according to the weight parts. Under nitrogen protection, raise the temperature to 75°C. After the reaction is self-exothermic, control the temperature at 120°C and keep it for 30 min. Add dicyclopentadiene to the reaction vessel at a rate of 1.1 g / min. After the dicyclopentadiene is added, keep it at the temperature for 2.3 h. The antioxidant is triphenyl phosphite.

[0074] (2) Ethylene glycol, propylene glycol, glycerol, maleic anhydride, phthalic anhydride and antioxidant are added to the reaction vessel of step (1) according to the weight parts; the temperature is raised to 147℃ and kept at 0.7h, then raised to 180℃, and raised to 197℃ at a rate of 13℃ / h and kept at 197℃ for 1.8h; dehydrated until the acid value reaches 18mgKOH / g; the antioxidant is triphenyl phosphite;

[0075] (3) Cool the product obtained in step (2) to 175°C and add the polymerization inhibitor according to the weight; cool to 115°C and add the stabilizer and diluent according to the weight; continue to cool to 55°C and add the defoamer; the defoamer is methyl silicone oil, the stabilizer is copper naphthenate, and the diluent is styrene; the polymerization inhibitor is composed of hydroquinone and p-benzoquinone in a weight ratio of 1:0.98; mix well to obtain unsaturated polyester resin for light-transmitting tiles.

[0076] Example 6

[0077] The preparation method in this embodiment adopts the following steps:

[0078] (1) Add water, ethylene glycol, maleic anhydride and antioxidant to the reaction vessel according to the weight parts. Under nitrogen protection, raise the temperature to 70°C. After the reaction is self-exothermic, control the temperature at 115°C and keep it for 28 min. Add dicyclopentadiene to the reaction vessel at a rate of 1.1 g / min. After the dicyclopentadiene is added, keep it at the temperature for 2.0 h. The antioxidant is triphenyl phosphite.

[0079] (2) Ethylene glycol, propylene glycol, glycerol, maleic anhydride, phthalic anhydride and antioxidant are added to the reaction vessel of step (1) according to the weight parts; the temperature is raised to 147℃ and kept at 0.7h, then raised to 180℃, and raised to 197℃ at a rate of 13℃ / h and kept at 197℃ for 1.8h; dehydrated until the acid value reaches 18mgKOH / g; the antioxidant is triphenyl phosphite;

[0080] (3) Cool the product obtained in step (2) to 170°C and add the polymerization inhibitor according to the weight parts; cool to 110°C and add the stabilizer and diluent according to the weight parts; continue to cool to 50°C and add the defoamer; the defoamer is methyl silicone oil, the stabilizer is copper naphthenate, and the diluent is styrene; the polymerization inhibitor is composed of hydroquinone and p-benzoquinone in a weight ratio of 1:1.04; mix well to obtain unsaturated polyester resin for light-transmitting tiles.

[0081] Example 7

[0082] The preparation method in this embodiment adopts the following steps:

[0083] (1) Add water, ethylene glycol, maleic anhydride and antioxidant to the reaction vessel according to the weight parts. Under nitrogen protection, raise the temperature to 80°C. After the reaction is self-exothermic, control the temperature at 125°C for 32 min. Add dicyclopentadiene to the reaction vessel at a rate of 1.2 g / min. After the dicyclopentadiene is added, keep the temperature for 2.5 h. The antioxidant is triphenyl phosphite.

[0084] (2) Ethylene glycol, propylene glycol, glycerol, maleic anhydride, phthalic anhydride and antioxidant are added to the reaction vessel of step (1) according to the weight parts; the temperature is raised to 147℃ and kept at 0.7h, then raised to 180℃, and raised to 197℃ at a rate of 13℃ / h and kept at 197℃ for 1.8h; dehydrated until the acid value reaches 16mgKOH / g; the antioxidant is triphenyl phosphite;

[0085] (3) Cool the product obtained in step (2) to 180°C and add the polymerization inhibitor according to the weight; cool to 120°C and add the stabilizer and diluent according to the weight; continue to cool to 60°C and add the defoamer; the defoamer is methyl silicone oil, the stabilizer is copper naphthenate, and the diluent is styrene; the polymerization inhibitor is composed of hydroquinone and p-benzoquinone in a weight ratio of 1:0.8; mix well to obtain unsaturated polyester resin for light-transmitting tiles.

[0086] Table 2 shows the raw material formulations (by weight) for Comparative Examples 1-5.

[0087] .

[0088] Table 3 shows the raw material formulations (by weight) for Comparative Examples 6-10.

[0089] .

[0090] Comparative Example 1

[0091] The preparation method of the unsaturated polyester resin for the light-transmitting tile described in this comparative example is the same as that in Example 5, except that the formulation is different. The formulation of this comparative example is shown in Table 2.

[0092] Comparative Example 2

[0093] The preparation method of the unsaturated polyester resin for the light-transmitting tile described in this comparative example is the same as that in Example 5, except that the formulation is different. The formulation of this comparative example is shown in Table 2.

[0094] Comparative Example 3

[0095] The preparation method of the unsaturated polyester resin for the light-transmitting tile described in this comparative example is the same as that in Example 5, except that the formulation is different. The formulation of this comparative example is shown in Table 2.

[0096] Comparative Example 4

[0097] The preparation method of the unsaturated polyester resin for the light-transmitting tile described in this comparative example is the same as that in Example 5, except that the formulation is different. The formulation of this comparative example is shown in Table 2.

[0098] Comparative Example 5

[0099] The preparation method of the unsaturated polyester resin for the light-transmitting tile described in this comparative example is the same as that in Example 5, except that the formulation is different. The formulation of this comparative example is shown in Table 2.

[0100] Comparative Example 6

[0101] The preparation method of the unsaturated polyester resin for the light-transmitting tile described in this comparative example is the same as that in Example 5, except that the formulation is different. The formulation of this comparative example is shown in Table 3.

[0102] Comparative Example 7

[0103] The preparation method of the unsaturated polyester resin for the light-transmitting tile described in this comparative example is the same as that in Example 5, except that the formulation is different. The formulation of this comparative example is shown in Table 3.

[0104] Comparative Example 8

[0105] The preparation method of the unsaturated polyester resin for the light-transmitting tile described in this comparative example is the same as that in Example 5, except that the formulation is different. The formulation of this comparative example is shown in Table 3.

[0106] Comparative Example 9

[0107] The preparation method of the unsaturated polyester resin for the light-transmitting tile described in this comparative example is the same as that in Example 5, except that the formulation is different. The formulation of this comparative example is shown in Table 3.

[0108] Comparative Example 10

[0109] The preparation method of the unsaturated polyester resin for the light-transmitting tile described in this comparative example is the same as that in Example 5, except that the formulation is different. The formulation of this comparative example is shown in Table 3.

[0110] Comparative Example 11

[0111] The formulation of the unsaturated polyester resin for the light-transmitting tile described in this comparative example is the same as that in Example 5, except that all of the ethylene glycol and maleic anhydride are added at once in step (1).

[0112] Step (1) Preparation method:

[0113] Water, ethylene glycol, maleic anhydride, and antioxidant were added to the reaction vessel according to their weight proportions. Under nitrogen protection, the temperature was raised to 75°C. After the reaction was exothermic, the temperature was maintained at 120°C for 30 minutes. Dicyclopentadiene was added to the reaction vessel at a rate of 1.1 g / min. After the addition of dicyclopentadiene, the temperature was maintained for 2.3 hours. The antioxidant was triphenyl phosphite.

[0114] Comparative Example 12

[0115] The formulation of the unsaturated polyester resin for the light-transmitting tile described in this comparative example is the same as that in Example 5, except that dicyclopentadiene is added to the reaction vessel at a rate of 1.0 g / min in step (1).

[0116] Step (1) Preparation method:

[0117] Water, ethylene glycol, maleic anhydride, and antioxidant were added to the reaction vessel according to the weight proportions. Under nitrogen protection, the temperature was raised to 75°C. After the reaction was exothermic, the temperature was controlled at 120°C and kept at that temperature for 30 minutes. Dicyclopentadiene was added to the reaction vessel at a rate of 1.0 g / min. After the addition of dicyclopentadiene was completed, the temperature was kept at that temperature for 2.3 hours. The antioxidant was triphenyl phosphite.

[0118] Comparative Example 13

[0119] The formulation of the unsaturated polyester resin for the light-transmitting tile described in this comparative example is the same as that in Example 5, except that dicyclopentadiene is added to the reaction vessel at a rate of 1.3 g / min in step (1).

[0120] Step (1) Preparation method:

[0121] Water, ethylene glycol, maleic anhydride, and antioxidant were added to the reaction vessel according to the weight proportions. Under nitrogen protection, the temperature was raised to 75°C. After the reaction was exothermic, the temperature was controlled at 120°C and kept at that temperature for 30 minutes. Dicyclopentadiene was added to the reaction vessel at a rate of 1.3 g / min. After the addition of dicyclopentadiene was completed, the temperature was kept at that temperature for 2.3 hours. The antioxidant was triphenyl phosphite.

[0122] Performance testing

[0123] The unsaturated polyester resins prepared in the examples and comparative examples were subjected to performance tests, and the specific test results are shown in Tables 4 and 5.

[0124] Tensile strength was tested in accordance with GB / T2567-2021;

[0125] The tensile modulus of elasticity was tested in accordance with GB / T2567-2021;

[0126] The elongation at break was tested in accordance with GB / T2567-2021;

[0127] Bending strength was tested in accordance with GB / T2567-2021;

[0128] The flexural modulus of elasticity was tested in accordance with GB / T2567-2021;

[0129] Impact strength was tested in accordance with GB / T2567-2021;

[0130] The Barcol hardness was tested according to GB / T3854-2017;

[0131] The heat distortion temperature was tested in accordance with GB / T1643-2019;

[0132] Viscosity was tested according to GB / T7193-2008;

[0133] The gelation time was tested according to GB / T7193-2008;

[0134] The exothermic peak was tested in accordance with GB / T7193-2008;

[0135] The refractive index was tested according to the Abbe refractometer operating procedure.

[0136] The gelation time was tested according to GB / T7193-2008;

[0137] The preparation of resin castings shall be in accordance with GB / T2567-2021.

[0138] Post-curing time refers to the time interval from when unsaturated polyester resin changes from a gel state (at which point the material is jelly-like and relatively soft) to when the temperature reaches its exothermic peak and remains stable for 30 seconds. During this process, the resin completes the transformation from a gel state to complete curing and ultimately exhibits a high degree of hardness.

[0139] Wetting test: Place the fiberglass cloth flat on the polyester film, cover it with the cut strand mat, pour the same weight of resin sample into the inverted funnel and start timing. Measure the length of the resin-wetted part at 3 min, 5 min, 7 min and 10 min after timing starts.

[0140] Table 4. Performance test results of the examples and comparative examples in liquid state.

[0141] .

[0142] Table 5. Performance test results of resin castings from the examples and comparative examples.

[0143] .

[0144] The liquid form of this invention is light in color and easily tinted. It has a refractive index of 1.5408–1.5425, a wettability of 8.6–8.9 cm, a viscosity of 200–210 mPa·s, a gel time of 4′18″–4′36″, and a post-curing time of 5′20″–5′48″, all within reasonable parameters. The exothermic peak is 175–178℃, and it exhibits no delamination or fluorescence defects. The casting of this invention has a tensile strength of 45–47 MPa, an elongation at break of 4.81–4.94%, a flexural strength of 81–86 MPa, an impact strength of 8.2–8.8 kJ / m², a heat distortion temperature of 50.1–50.5℃, and strong heat resistance. Its Barcol hardness is 36–37 HBa, meeting the requirements for use in skylights. This invention achieves easy processing, high performance, and high stability of the resin by balancing raw material ratios and process parameters, providing high-quality raw materials for the production of skylights and possessing practical application value. The color effect of Example 7 is superior to that of other examples, especially suitable for high-end building skylights, airport lighting facilities, high-end commercial complex skylights, star-rated hotel domes, and other high-end scenarios with strict requirements for appearance and light transmission quality; the other examples are more economical, effectively controlling costs while ensuring basic performance, and are more suitable for public facilities, agricultural greenhouses, and scenarios with large usage and high cost sensitivity.

[0145] Comparative Examples 1 and 3 did not contain glycerol. The elongation at break and heat distortion temperature of the resin castings in these two examples were lower than those in the examples, and the resin color was yellow, resulting in a lower refractive index and reduced wettability. Comparative Examples 2 and 4 did not contain propylene glycol. Because both ethylene glycol and glycerol have symmetrical structures and high crystallinity, the products exhibited layering, making related performance tests impossible. Comparative Examples 5 and 6 contained excessive glycerol (propylene glycol to glycerol mass ratio of 0.9). The increased glycerol content caused fluorescence in the products, making related performance tests impossible. Comparative Examples 7 and 8 contained insufficient glycerol (propylene glycol to glycerol mass ratio of 1.4). Compared to the examples, the increased propylene glycol content resulted in a darker product color and decreased refractive index, wettability, and heat distortion temperature. Comparative Example 9 did not contain glycerol but increased ethylene glycol content. The color was similar to the examples, but the gel time and post-curing time were accelerated, and the strength was significantly reduced. Comparative Example 10, without the addition of glycerol, had an increased amount of dicyclopentadiene, resulting in a darker color, the highest viscosity of the finished product, longer gel time and post-curing time, a lower exothermic peak, and reduced physical properties.

[0146] In Comparative Example 11, the addition of all ethylene glycol and maleic anhydride in step (1) resulted in significantly lower mechanical properties and heat resistance compared to Example 5. The bicyclic dropping acceleration rates of Comparative Examples 12 and 13 exceeded the range specified in this invention, and the change in the preparation method led to a decrease in all properties compared to Example 5.

[0147] As can be seen from the above conclusions, when the weight ratio of propylene glycol to glycerol is 1.0 to 1.36, propylene glycol accounts for 18 to 20% of the total alcohol, and the weight ratio of maleic anhydride, dicyclopentadiene, and phthalic anhydride is 1.70 to 1.80: 0.85 to 1.00: 1, and the preparation method of the present invention is followed, an unsaturated polyester resin with light color and easy color adjustment, high refractive index, good wettability, and the best comprehensive performance can be obtained.

[0148] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the protection scope of the present invention.

Claims

1. An unsaturated polyester resin for translucent roof tiles, characterized in that, By weight, it consists of the following components: 110.5–122 parts dicyclopentadiene, 128.0–133.2 parts ethylene glycol, 36.0–40.8 parts propylene glycol, 30–36 parts glycerol, 219.6–221.0 parts maleic anhydride, 122–130 parts phthalic anhydride, 0.5–0.7 parts antioxidant, 0.06–0.08 parts polymerization inhibitor, 0.6–0.8 parts defoamer, 0.02–0.04 parts stabilizer, 333–335 parts diluent, and 20.18–20.3 parts water; The weight ratio of propylene glycol to glycerol is 1.00–1.36:1, and the weight ratio of maleic anhydride, dicyclopentadiene, and phthalic anhydride is 1.70–1.80:0.85–1.00:1; the purity of dicyclopentadiene is greater than or equal to 75 wt%, and the color number is less than or equal to 50 Hazen; The method for preparing the unsaturated polyester resin for the light-transmitting tile includes the following steps: (1) Add water, ethylene glycol, maleic anhydride and antioxidant to the reaction vessel according to the weight parts, heat to 70-80℃, and after the reaction is exothermic, keep it at 115-125℃ for 28-32 min, then add dicyclopentadiene and keep it at 2.0-2.5 h; (2) Add ethylene glycol, propylene glycol, glycerol, maleic anhydride, phthalic anhydride and antioxidant to the reaction vessel of step (1) according to the weight parts, heat to 145-150℃ and keep at the temperature for 0.5-1.0h, then heat to 175-185℃, and then heat to 195-200℃ at a rate of 12-14℃ / h and keep at the temperature for 1.5-2.0h; dehydrate until the acid value reaches 15-20mgKOH / g; (3) Cool the product obtained in step (2) to 170-180°C and add the polymerization inhibitor according to the weight; cool to 110-120°C and add the stabilizer and diluent according to the weight; continue to cool to 50-60°C and add the defoamer; mix well to obtain unsaturated polyester resin for light-transmitting tiles. In step (1), the amount of ethylene glycol added accounts for 50% of the total amount of ethylene glycol added, and in step (2), the amount of ethylene glycol added accounts for 50% of the total amount of ethylene glycol added; in step (1), the amount of maleic anhydride added accounts for 50% of the total amount of maleic anhydride added, and in step (2), the amount of maleic anhydride added accounts for 50% of the total amount of maleic anhydride added; in step (1), the amount of antioxidant added accounts for 40% of the total amount of antioxidant added, and in step (2), the amount of antioxidant added accounts for 60% of the total amount of antioxidant added.

2. The unsaturated polyester resin for translucent roofing sheets according to claim 1, characterized in that, By weight, it consists of the following components: 114.0–119.5 parts dicyclopentadiene, 129.0–130.6 parts ethylene glycol, 37.8–40.0 parts propylene glycol, 32–35 parts glycerol, 220.0–220.6 parts maleic anhydride, 124–128 parts phthalic anhydride, 0.55–0.65 parts antioxidant, 0.065–0.075 parts polymerization inhibitor, 0.65–0.75 parts defoamer, 0.025–0.035 parts stabilizer, 333.1–334.0 parts diluent, and 20.21–20.27 parts water.

3. The unsaturated polyester resin for translucent roofing sheets according to claim 1, characterized in that, The weight ratio of propylene glycol to glycerol is 1.08 to 1.25:

1.

4. The unsaturated polyester resin for translucent roofing sheets according to claim 1, characterized in that, The propylene glycol accounts for 18.7 to 19.9% ​​of the total alcohol by weight.

5. The unsaturated polyester resin for translucent roofing sheets according to claim 1, characterized in that, The purity of the dicyclopentadiene is 75-80 wt%, and the color number is 30-50 Hazen.

6. The unsaturated polyester resin for translucent roofing sheets according to claim 1, characterized in that, The weight ratio of maleic anhydride to phthalic anhydride is 1.72 to 1.77:

1.

7. The unsaturated polyester resin for translucent roofing sheets according to claim 1, characterized in that, The polymerization inhibitor is at least one of hydroquinone and p-benzoquinone.

8. The unsaturated polyester resin for translucent roofing sheets according to claim 1 or 7, characterized in that, The polymerization inhibitor is composed of hydroquinone and p-benzoquinone in a weight ratio of 1:0.5~1.

1.

9. The method for preparing an unsaturated polyester resin for light-transmitting tiles according to claim 1, characterized in that, In step (1), the addition rate of dicyclopentadiene is 1.1 to 1.2 g / min.