Unsaturated polyester resin as well as preparation method and application thereof

Abstract

The invention discloses unsaturated polyester resin as well as a preparation method and application thereof, and belongs to the technical field of unsaturated polyester resin. The unsaturated polyester resin is prepared from the following raw materials in parts by weight: 70 to 100 parts by weight of phthalic anhydride, 80 to 120 parts by weight of maleic anhydride, 50 to 100 parts by weight of diethylene glycol, 10 to 40 parts by weight of ethylene glycol, 20 to 70 parts by weight of propylene glycol and 600 to 700 parts by weight of diluent, wherein the molar ratio of the maleic anhydride to the phthalic anhydride is (1.2-2.6): 1. The unsaturated polyester resin has good compatibility with other components in the color paste, and the color paste containing the unsaturated polyester resin has excellent adhesive force and tinting strength and also has good storage stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of unsaturated polyester resins, and particularly relates to an unsaturated polyester resin, a preparation method thereof, and an application thereof. Background Art

[0002] Unsaturated polyester is a polymer formed by dehydration polycondensation of dibasic acid and diol at high temperature. Unsaturated polyester resin can be obtained by diluting with crosslinking monomers or active solvents. With the growth of the output of unsaturated polyester resin, due to its excellent properties, its applications have gradually extended to many aspects of human life, such as artificial stone, daylighting tiles, hand-laid fiberglass, vacuum infusion, etc.

[0003] Due to the wide range of applications and rich variety of products, people's requirements for the color appearance and performance of products are becoming more and more strict. The traditional coloring method of directly adding pigments to the system can no longer meet the requirements, so color pastes came into being. The main production process of color paste is to pre-stir and mix pigments with matrix resin, and then grind them with a grinding machine to make the finished color paste.

[0004] The applicant found in the research that the existing unsaturated polyester resins have the following problems: First of all, the matrix resins commonly used in color pastes on the market at present are mostly prepared from saturated acids and diols. The matrix resin prepared under this formula does not contain double bonds and does not add diluents, and the compatibility of the obtained matrix resin with other components in the color paste is poor, thus having an adverse effect on the adhesion and coloring power of the color paste.

[0005] Secondly, for the color paste prepared from the existing unsaturated polyester resin, the pigments are easy to float, settle, and decolorize. After the color paste is placed for a period of time, there is a color difference between the top color and the bottom color when in use; as time goes by, it is extremely easy to cause the color paste to float and settle, and the anti-decolorization ability is poor. The longer the time, the greater the color difference, resulting in poor quality control of the color paste products made as reported by downstream customers.

[0006] Therefore, it is of great significance to find a color paste matrix resin that can effectively improve the compatibility of the matrix resin with other components in the color paste, make the color paste not easy to float and settle for a long time, and has certain stability, anti-decolorization ability, and coloring ability. Summary of the Invention

[0007] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide an unsaturated polyester resin, a preparation method thereof, and an application thereof. The unsaturated polyester resin is used as an adhesive for color paste, has good compatibility with other components in the color paste, and can improve the adhesion, coloring power, and storage stability of the prepared color paste.

[0008] To achieve the above object, according to one aspect of the present invention, there is provided an unsaturated polyester resin, comprising the following raw materials in parts by weight: 70-100 parts by weight of phthalic anhydride, 80-120 parts by weight of maleic anhydride, 50-100 parts by weight of diethylene glycol, 10-40 parts by weight of ethylene glycol, 20-70 parts by weight of propylene glycol, and 600-700 parts by weight of a diluent; wherein, the molar ratio of maleic anhydride to phthalic anhydride is 1.2-2.6:1.

[0009] In the present invention, the raw materials of the unsaturated polyester resin include 70-100 parts by weight of phthalic anhydride. It can be understood that the parts by weight can be any specific value among 70, 80, 90, 100 or any value within the range of 70-100. Preferably, the raw materials of the unsaturated polyester resin include 85-100 parts by weight of phthalic anhydride. More preferably, the raw materials of the unsaturated polyester resin include 85 parts by weight of phthalic anhydride.

[0010] In the present invention, the raw materials of the unsaturated polyester resin include 80-120 parts by weight of maleic anhydride. It can be understood that the parts by weight can be any specific value among 80, 90, 100, 110, 120 or any value within the range of 80-120. Preferably, the raw materials of the unsaturated polyester resin include 100-120 parts by weight of maleic anhydride. More preferably, the raw materials of the unsaturated polyester resin include 120 parts by weight of maleic anhydride.

[0011] In the present invention, the molar ratio of maleic anhydride to phthalic anhydride is 1.2 - 2.6:1. It can be understood that the molar ratio can be any specific value among 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2.0:1, 2.1:1, 2.2:1, 2.3:1, 2.4:1, 2.5:1, 2.6:1 or any value within the range of 1.2 - 2.6:1. Preferably, the molar ratio of maleic anhydride to phthalic anhydride is 1.5 - 2.5:1. The inventors found that the molar ratio of maleic anhydride to phthalic anhydride is crucial for the content and distribution of unsaturated double bonds in the unsaturated polyester. Limiting the molar ratio within the above range results in good compatibility between the obtained unsaturated polyester resin and other components in the color paste. If the proportion of maleic anhydride is large, the content of double bonds in the obtained unsaturated polyester chain is large and dense, and the intermolecular and intramolecular interaction forces of the unsaturated polyester chain are large, weakening the flexibility of the color paste matrix resin. Other components in the color paste, such as pigment powder, are not easily dispersed evenly within the long-chain unsaturated polyester molecules, easily leading to sedimentation or floating of the color paste in a short time, and poor stability. If the proportion of maleic anhydride is small, the content of double bonds in the obtained unsaturated polyester chain is small and relatively dispersed, and the intermolecular interaction forces of the unsaturated polyester molecular chains are small, resulting in a decrease in the adhesion of other components in the color paste, such as pigment powder, to the unsaturated polyester chain, thereby leading to disadvantages such as poor coloring power and reduced anti-decoloring ability of the color paste matrix, resulting in uneven colors of the product.

[0012] In the present invention, the raw materials of the unsaturated polyester resin include 50 - 100 parts by weight of diethylene glycol. It can be understood that the parts by weight can be any specific value among 50, 60, 70, 80, 90, 100 or any value within the range of 50 - 100. Preferably, the raw materials of the unsaturated polyester resin include 65 - 100 parts by weight of diethylene glycol. More preferably, the raw materials of the unsaturated polyester resin include 65 parts by weight of diethylene glycol.

[0013] In the present invention, the raw materials of the unsaturated polyester resin include 10 - 40 parts by weight of ethylene glycol. It can be understood that the parts by weight can be any specific value among 10, 20, 30, 40 or any value within the range of 10 - 40. Preferably, the raw materials of the unsaturated polyester resin include 15 - 40 parts by weight of ethylene glycol. More preferably, the raw materials of the unsaturated polyester resin include 15 parts by weight of ethylene glycol.

[0014] In the present invention, the raw materials of the unsaturated polyester resin include 20-70 parts by weight of propylene glycol. It can be understood that the parts by weight can be any specific value among 20, 30, 40, 50, 60, 70 or any value within the range of 20-70. Preferably, the raw materials of the unsaturated polyester resin include 35-70 parts by weight of propylene glycol. More preferably, the raw materials of the unsaturated polyester resin include 35 parts by weight of propylene glycol.

[0015] In the present invention, the mass ratio of diglycol, ethylene glycol and propylene glycol is 5-10:1-4:2-7. Preferably, the mass ratio of diglycol, ethylene glycol and propylene glycol is 6.5:4:3.5. By controlling the mass ratio of diglycol, ethylene glycol and propylene glycol within the above range, the present invention can ensure that the various properties of the matrix resin are in the best balanced position. Under the limitation of a certain alcohol-acid ratio, the proportion of the total alcohol used in the formula can be determined. By adjusting the mass ratio of the three diols, the synergistic effect of the three diols can be maximized. Among them, diglycol and propylene glycol synergistically improve the toughness and compatibility of the unsaturated polyester resin, which is beneficial to the uniform dispersion of other components of the color paste in the matrix resin, and the color paste is not easy to float and settle. And propylene glycol also has the effect of lightening the appearance of the color paste matrix and improving the coloring power of the matrix resin of the color paste. Ethylene glycol can ensure that the matrix resin of the color paste has a certain strength and reduce the influence of the matrix resin of the color paste on the properties of other resins. If the amount of any one of the diols is too much or too little, it will cause performance deviation of the matrix resin, and finally lead to poor performance of the color paste.

[0016] In the present invention, the raw materials of the unsaturated polyester resin include 600-700 parts by weight of diluent. It can be understood that the parts by weight can be any specific value among 600, 610, 620, 630, 640, 650, 660, 670, 680, 690, 700 or any value within the range of 600-700. In the present invention, the diluent is dibutyl phthalate. In the present invention, the weight proportion of the diluent in the raw materials is 60-70%, and it can be understood that the weight proportion can be any specific value among 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70% or any value within the range of 60-70%.

[0017] The inventor found that using dibutyl phthalate as the diluent can not only reduce the viscosity of the unsaturated polyester, but also increase the flexibility of the unsaturated polyester, weaken the intermolecular interaction force, and promote the uniform dispersion of other components such as pigment powder in the color paste matrix resin, so that the color paste is not easy to float and settle for a long time. At the same time, when the matrix resin is used at a lower temperature, due to the presence of dibutyl phthalate, the fluidity of the matrix resin can be ensured.

[0018] In the present invention, the molar ratio of hydroxyl groups to carboxyl groups in the raw materials is 0.84 - 1.24, preferably 0.94 - 1.24. By controlling the molar ratio of hydroxyl groups to carboxyl groups in the raw materials within the above range, the unsaturated polyester resin can have appropriate toughness and strength at the same time.

[0019] According to one aspect of the present invention, there is also provided a method for preparing the unsaturated polyester resin described in any one of the above, comprising the following steps: (1) Phthalic anhydride, maleic anhydride, diethylene glycol, ethylene glycol, and propylene glycol are added into a reaction kettle in the order of adding liquid materials first and then solid materials, and the temperature is raised to 150 - 165 °C and kept warm for 0.5 - 1 h; (2) The temperature is continuously raised to 190 - 220 °C and kept warm for 2 - 4 h. When the rotational viscosity reaches 200 - 220 cp, the temperature is decreased; (3) The temperature is continuously decreased to below 120 °C, and a diluent is added and stirred evenly to obtain the unsaturated polyester resin.

[0020] In the present invention, in step (1), phthalic anhydride, maleic anhydride, diethylene glycol, ethylene glycol, and propylene glycol are added into a reaction kettle in the order of adding liquid materials first and then solid materials, and the temperature is raised to 150 - 165 °C and kept warm for 0.5 - 1 h. Preferably, the specific operation of raising the temperature is as follows: first, the temperature is raised at a rate of 50 °C / h to 80 - 140 °C, and after the temperature in the reaction kettle is stable, the temperature is raised at a rate of 20 °C / h to 150 - 165 °C. More preferably, in step (1), it is ensured that the distillation head temperature of the fractionating tower does not exceed 102 °C.

[0021] In the present invention, in step (2), the temperature is continuously raised to 190 - 220 °C and kept warm for 2 - 4 h. When the rotational viscosity reaches 200 - 220 cp, the temperature is decreased. Preferably, the rate of raising the temperature is 15 - 18 °C / h. In the present invention, the rotational viscosity refers to the resistance generated by a fluid when it is subjected to a shear force. Preferably, the test method for the rotational viscosity is as follows: a certain amount of sample is taken, and a diluent is added for dilution according to the mass ratio of the sample to the diluent of 3 - 4:7 - 6, and the rotational viscosity at 25 °C is detected.

[0022] In the present invention, in step (3), the temperature is continuously decreased to below 120 °C, and a diluent is added and stirred evenly to obtain the unsaturated polyester resin. Preferably, the temperature is continuously decreased to 120 - 130 °C, and a diluent is added and stirred evenly. Preferably, the rate of decreasing the temperature is 50 °C / h.

[0023] Application of unsaturated polyester resin or unsaturated polyester resin prepared by a preparation method, in the field of making color pastes. Further, the application method is as follows: Take unsaturated polyester resin as the matrix resin, add colorants, and use ultrasonic waves to disperse the colorants evenly in the unsaturated polyester resin to obtain a color paste. The mass ratio of the unsaturated polyester resin to the colorants is 1000:0.1 - 10.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) By controlling the molar ratio of maleic anhydride to phthalic anhydride in the unsaturated polyester resin raw material, the present invention regulates the structure of the unsaturated polyester, especially the content and distribution of double bonds in the unsaturated polyester, so that the obtained unsaturated polyester resin has good compatibility with other components in the color paste, such as pigment powder. The color paste containing the unsaturated polyester resin has excellent adhesion and coloring power, and at the same time has good storage stability.

[0025] (2) By using dibutyl phthalate as a diluent, the present invention can not only reduce the viscosity of the unsaturated polyester, but also increase the flexibility of the unsaturated polyester, weaken the intermolecular interaction force, and promote the uniform dispersion of other components in the color paste, such as pigment powder, in the color paste resin matrix, so that the color paste is not easily floated and settled for a long time.

[0026] (3) The present invention also provides a preparation method of an unsaturated polyester resin, and obtains a specific unsaturated polyester resin, so that the color paste containing the unsaturated polyester resin has excellent adhesion and coloring power, and at the same time has good storage stability. Description of the Drawings

[0027] Figure 1 It is a schematic diagram for comparing the appearances of the examples and the comparative examples.

[0028] Figure 2 It is a schematic diagram for comparing the color paste performances of the matrix resins of Example 1, Comparative Example 2, and Comparative Example 6. Detailed Embodiments

[0029] To enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and phrases mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in this text have the ordinary meanings understood by those skilled in the art for the present invention. When there are conflicts, the definitions in this specification shall prevail.

[0030] The theories or mechanisms described and disclosed in this text, whether right or wrong, shall not limit the scope of the present invention in any way, that is, the content of the present invention can be implemented without being limited by any specific theory or mechanism.

[0031] In this text, when describing embodiments or examples, it should be understood that it is not intended to limit the present invention to these embodiments or examples. On the contrary, all alternatives, improvements, and equivalents of the methods and materials described in the present invention can be covered within the scope defined by the claims.

[0032] In this text, for the sake of brevity of description, not all possible combinations of all technical features in each embodiment or example are described. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each embodiment or example can be combined arbitrarily, and all possible combinations should be considered as the scope described in this specification.

[0033] The present invention provides an unsaturated polyester resin, comprising the following raw materials in parts by weight: 70 - 100 parts by weight of phthalic anhydride, 80 - 120 parts by weight of maleic anhydride, 50 - 100 parts by weight of diethylene glycol, 10 - 40 parts by weight of ethylene glycol, 20 - 70 parts by weight of propylene glycol, and 600 - 700 parts by weight of a diluent; wherein, the molar ratio of maleic anhydride to phthalic anhydride is 1.2 - 2.6:1.

[0034] In the present invention, the diluent is dibutyl phthalate.

[0035] In the present invention, the weight proportion of the diluent in the raw materials is 60 - 70%.

[0036] In the present invention, the molar ratio of hydroxyl groups to carboxyl groups in the raw materials is 0.84 - 1.24.

[0037] In the present invention, the mass ratio of diethylene glycol, ethylene glycol, and propylene glycol is 5 - 10:1 - 4:2 - 7.

[0038] According to another aspect of the present invention, there is also provided a method for preparing the unsaturated polyester resin described in any one of the above, comprising the following steps: (1) Charge phthalic anhydride, maleic anhydride, diethylene glycol, ethylene glycol, and propylene glycol into a reaction kettle in the order of charging liquid materials first and then solid materials, heat up to 150 - 165°C, and keep warm for 0.5 - 1 h; (2) Continue to heat up to 190 - 220°C, keep warm for 2 - 4 h, and when the rotational viscosity reaches 200 - 220 cp, cool down; (3) Continuously cool down to below 120°C, add the diluent and stir evenly to obtain the unsaturated polyester resin.

[0039] In the present invention, in step (1), the specific operation of heating up is: first heat up at a heating rate of 50°C / h to 80°C, and after the temperature in the reaction kettle is stable, heat up at a heating rate of 20°C / h to 150 - 165°C.

[0040] In the present invention, in step (2), the heating rate is 15-18 °C / h.

[0041] In the present invention, in step (2), the test method for rotational viscosity is as follows: Take a certain amount of sample, add diluent for dilution according to the mass ratio of the sample to the diluent of 3-4:6-7, and detect the rotational viscosity at 25 °C.

[0042] According to another aspect of the present invention, there is also provided an application of the unsaturated polyester resin described in any one of the above or the unsaturated polyester resin prepared by the preparation method described in any one of the above in color paste.

[0043] The present invention will be described in detail below through examples. It should be understood that the following examples are only used to further explain and illustrate the content of the present invention by way of example, and are not used to limit the present invention. Among them, Example 1 is the best example.

[0044] The chemical aids used in the examples and comparative examples of the present invention are all commercially available, and the specific information is as follows: Phthalic anhydride, maleic anhydride, diethylene glycol, ethylene glycol, propylene glycol, dibutyl phthalate, styrene: all purchased from Aladdin Reagent Co., Ltd. Phthalocyanine blue: powder, purchased from Clariant.

[0045] Example 1 An unsaturated polyester resin described in this example includes the following raw materials in parts by weight: 85 parts by weight of phthalic anhydride, 120 parts by weight of maleic anhydride, 65 parts by weight of diethylene glycol, 40 parts by weight of ethylene glycol, 35 parts by weight of propylene glycol, and 650 parts by weight of diluent dibutyl phthalate; wherein, the molar ratio of maleic anhydride to phthalic anhydride is 2.1:1, the mass ratio of dibutyl phthalate in the raw materials is 65.3%, and the molar ratio of hydroxyl groups to carboxyl groups in the raw materials is 0.94.

[0046] The preparation method of the unsaturated polyester resin described in this example includes the following steps: (1) Put phthalic anhydride, maleic anhydride, diethylene glycol, ethylene glycol, and propylene glycol into the reaction kettle in the order of first adding liquid materials and then adding solid materials. First, heat up to 80 °C at a heating rate of 50 °C / h. After the temperature in the reaction kettle is stable, heat up to 160 °C at a heating rate of 20 °C / h, keep warm for 0.5 h, and control the distillate head temperature not to exceed 102 °C; (2) Continue to heat up to 200 °C at a heating rate of 18 °C / h, keep warm for 3 h, then take a certain amount of sample, add diluent for dilution according to the mass ratio of the sample to the diluent of 3:7, detect the rotational viscosity at 25 °C, and cool down when the rotational viscosity reaches 210 cp; (3) Continuously cool down at a rate of 50 °C / h to below 120 °C, add a diluent and stir evenly to obtain the unsaturated polyester resin.

[0047] Example 2 An unsaturated polyester resin described in this example includes the following raw materials in parts by weight: 70 parts by weight of phthalic anhydride, 120 parts by weight of maleic anhydride, 100 parts by weight of diethylene glycol, 15 parts by weight of ethylene glycol, 70 parts by weight of propylene glycol, and 600 parts by weight of dibutyl phthalate as a diluent; among them, the molar ratio of maleic anhydride to phthalic anhydride is 2.6:1, the mass proportion of dibutyl phthalate in the raw materials is 61.5%, and the molar ratio of hydroxyl groups to carboxyl groups in the raw materials is 1.24.

[0048] The preparation method of the unsaturated polyester resin described in this example includes the following steps: (1) Put phthalic anhydride, maleic anhydride, diethylene glycol, ethylene glycol, and propylene glycol into the reaction kettle in the order of adding liquid materials first and then solid materials. First, heat up to 80 °C at a rate of 50 °C / h. After the temperature in the reaction kettle is stable, heat up to 150 °C at a rate of 20 °C / h, keep warm for 1 h, and control the distillate head temperature not to exceed 102 °C; (2) Continue to heat up to 190 °C at a rate of 18 °C / h, keep warm for 4 h, then take a certain amount of sample, add a diluent for dilution according to the mass ratio of the sample to the diluent of 3:7, detect the rotational viscosity at 25 °C, and when the rotational viscosity reaches 200 cp, cool down; (3) Continuously cool down at a rate of 50 °C / h to below 120 °C, add a diluent and stir evenly to obtain the unsaturated polyester resin.

[0049] Example 3 An unsaturated polyester resin described in this example includes the following raw materials in parts by weight: 80 parts by weight of phthalic anhydride, 80 parts by weight of maleic anhydride, 70 parts by weight of diethylene glycol, 10 parts by weight of ethylene glycol, 60 parts by weight of propylene glycol, and 700 parts by weight of dibutyl phthalate; among them, the molar ratio of maleic anhydride to phthalic anhydride is 1.5:1, the mass proportion of dibutyl phthalate as a diluent in the raw materials is 70%, and the molar ratio of hydroxyl groups to carboxyl groups in the raw materials is 1.19.

[0050] The preparation method of the unsaturated polyester resin described in this example includes the following steps: (1) Charge phthalic anhydride, maleic anhydride, diethylene glycol, ethylene glycol, and propylene glycol into the reaction kettle in the order of first charging liquid materials and then solid materials. First, heat up to 140°C at a heating rate of 50°C / h. After the temperature in the reaction kettle stabilizes, heat up to 165°C at a heating rate of 20°C / h, keep warm for 0.5 h, and control the distillate head temperature not to exceed 102°C. (2) Continue to heat up to 220°C at a heating rate of 18°C / h, keep warm for 2 h, then take a certain amount of sample, add diluent for dilution according to the mass ratio of the sample to the diluent of 4:6, detect the rotational viscosity at 25°C, and cool down when the rotational viscosity reaches 220 cp. (3) Continuously cool down to below 120°C at a cooling rate of 50°C / h, add diluent and stir evenly to obtain the unsaturated polyester resin.

[0051] Example 4 An unsaturated polyester resin described in this example includes the following raw materials in parts by weight: 100 parts by weight of phthalic anhydride, 115 parts by weight of maleic anhydride, 50 parts by weight of diethylene glycol, 30 parts by weight of ethylene glycol, 45 parts by weight of propylene glycol, and 700 parts by weight of dibutyl phthalate as the diluent; wherein, the molar ratio of maleic anhydride to phthalic anhydride is 1.7:1, the mass proportion of dibutyl phthalate in the raw materials is 67.3%, and the molar ratio of hydroxyl groups to carboxyl groups in the raw materials is 0.84.

[0052] The preparation method of the unsaturated polyester resin described in this example includes the following steps: (1) Charge phthalic anhydride, maleic anhydride, diethylene glycol, ethylene glycol, and propylene glycol into the reaction kettle in the order of first charging liquid materials and then solid materials. First, heat up to 80°C at a heating rate of 50°C / h. After the temperature in the reaction kettle stabilizes, heat up to 165°C at a heating rate of 20°C / h, keep warm for 0.5 h, and control the distillate head temperature not to exceed 102°C. (2) Continue to heat up to 210°C at a heating rate of 18°C / h, keep warm for 3 h, then take a certain amount of sample, add diluent for dilution according to the mass ratio of the sample to the diluent of 3:7, detect the rotational viscosity at 25°C, and cool down when the rotational viscosity reaches 200 cp. (3) Continuously cool down to below 120°C at a cooling rate of 50°C / h, add diluent and stir evenly to obtain the unsaturated polyester resin.

[0053] Example 5 An unsaturated polyester resin according to this embodiment comprises the following raw materials in parts by weight: 90 parts by weight of phthalic anhydride, 100 parts by weight of maleic anhydride, 80 parts by weight of diethylene glycol, 25 parts by weight of ethylene glycol, 20 parts by weight of propylene glycol, and 473 parts by weight of dibutyl phthalate as a diluent; wherein, the molar ratio of maleic anhydride to phthalic anhydride is 1.2:1, the mass proportion of dibutyl phthalate in the raw materials is 60%, and the molar ratio of hydroxyl groups to carboxyl groups in the raw materials is 0.87.

[0054] The preparation method of the unsaturated polyester resin according to this embodiment comprises the following steps: (1) Charge phthalic anhydride, maleic anhydride, diethylene glycol, ethylene glycol, and propylene glycol into a reaction kettle in the order of charging liquid materials first and then solid materials. First, heat up to 80°C at a heating rate of 50°C / h. After the temperature in the reaction kettle is stable, heat up to 155°C at a heating rate of 20°C / h, keep the temperature for 0.5 h, and control the distillate head temperature not to exceed 102°C; (2) Continue to heat up to 195°C at a heating rate of 15°C / h, keep the temperature for 2 h, then take a certain amount of sample, add a diluent for dilution according to the mass ratio of the sample to the diluent of 3:7, detect the rotational viscosity at 25°C, and when the rotational viscosity reaches 200 cp, cool down; (3) Continuously cool down to below 120°C at a cooling rate of 50°C / h, add the diluent and stir evenly to obtain the unsaturated polyester resin.

[0055] Comparative Example 1 The preparation method of the unsaturated polyester resin in this comparative example is exactly the same as that in Example 1, except that the molar ratio of maleic anhydride to phthalic anhydride is 0.86:1, that is, the unsaturated polyester resin comprises the following raw materials in parts by weight: 130 parts by weight of phthalic anhydride, 75 parts by weight of maleic anhydride, 65 parts by weight of diethylene glycol, 40 parts by weight of ethylene glycol, 35 parts by weight of propylene glycol, and 650 parts by weight of dibutyl phthalate as a diluent.

[0056] Comparative Example 2 The preparation method of the unsaturated polyester resin in this comparative example is exactly the same as that in Example 1, except that the molar ratio of maleic anhydride to phthalic anhydride is 2.9:1, that is, the unsaturated polyester resin comprises the following raw materials in parts by weight: 70 parts by weight of phthalic anhydride, 135 parts by weight of maleic anhydride, 65 parts by weight of diethylene glycol, 40 parts by weight of ethylene glycol, 35 parts by weight of propylene glycol, and 650 parts by weight of dibutyl phthalate as a diluent.

[0057] Comparative Example 3 The preparation method of the unsaturated polyester resin in this comparative example is exactly the same as that in Example 1, except that the mass proportion of dibutyl phthalate in the raw materials is 56%, that is, the unsaturated polyester resin comprises the following raw materials in parts by weight: 85 parts by weight of phthalic anhydride, 120 parts by weight of maleic anhydride, 65 parts by weight of diethylene glycol, 40 parts by weight of ethylene glycol, 35 parts by weight of propylene glycol, and 439 parts by weight of the diluent dibutyl phthalate; wherein, the molar ratio of maleic anhydride to phthalic anhydride is 2.1:1, and the mass proportion of dibutyl phthalate in the raw materials is 56%.

[0058] Comparative Example 4 The preparation method of the unsaturated polyester resin in this comparative example is exactly the same as that in Example 1, except that the mass proportion of dibutyl phthalate in the raw materials is 75%, that is, the unsaturated polyester resin comprises the following raw materials in parts by weight: 85 parts by weight of phthalic anhydride, 120 parts by weight of maleic anhydride, 65 parts by weight of diethylene glycol, 40 parts by weight of ethylene glycol, 35 parts by weight of propylene glycol, and 1035 parts by weight of the diluent dibutyl phthalate; wherein, the molar ratio of maleic anhydride to phthalic anhydride is 2.1:1, and the mass proportion of dibutyl phthalate in the raw materials is 75%.

[0059] Comparative Example 5 The preparation method of the unsaturated polyester resin in this comparative example is exactly the same as that in Example 1, except that the used diluent dibutyl phthalate is replaced with styrene of equal mass.

[0060] Comparative Example 6 The preparation method of the unsaturated polyester resin in this comparative example is exactly the same as that in Example 1, except that no diluent is added.

[0061] Performance Test The unsaturated polyester resins obtained in Examples 1-5 and Comparative Examples 1-6 were subjected to performance tests according to the following method, and the specific results are shown in Table 1.

[0062] (1) Appearance: Visual inspection; (2) Viscosity: Tested according to the standard of GB / T24148.4-2009; (3) Acid value: Tested according to the standard of GB2895-1982; Table 1 Resin Properties of Examples 1-5 and Comparative Examples 1-6 .

[0063] From Table 1 and Figure 1 it can be seen that the appearance of the unsaturated polyester resins obtained in Examples 1-5 of the present invention is light-colored and transparent, the viscosity is between 180-200 mPa·s, and the acid value is between 6.2-8 mgKOH / g.

[0064] As shown in reference to Figure 1 below, against a white background, the color difference can be more clearly contrasted. The lighter and more transparent the color, the better the effect and the better the appearance. Examples 1-5 can all reach the level of light color and transparency. Among them, Examples 1, 2, 3, and 5 show an effect better than light color and transparency, and can reach colorless transparency by naked-eye observation. Although Comparative Examples 1, 3, 5, and 6 also reach the level of light color and transparency, when observed and compared by the naked eye, they are still slightly less light in color than Examples 1-5. Among them, Comparative Examples 2 and 4 perform the worst, and an obvious light yellow color can be seen. If the unsaturated polyester resin itself has a color, it will interfere with the color development of the color powder during subsequent mixing with the color powder, resulting in color deviation of the prepared color paste, and it is difficult for downstream customers to accurately adjust the color during application.

[0065] Color paste performance test: Preparation of color paste: Take 1 kg of the unsaturated polyester resins obtained from Examples 1-5 and Comparative Examples 1-6 respectively, add 1 g of phthalocyanine blue color powder, and use ultrasonic waves to disperse the phthalocyanine blue evenly in the matrix resin to obtain 11 groups of different color pastes, and conduct color paste performance tests according to the following methods. The specific results are shown in Table 2.

[0066] (1) Compatibility: Test according to the standard of GB / T21473-2008; (2) Storage stability: Let it stand still at room temperature and observe whether there is sedimentation; (3) Relative coloring power: Test according to the standard of GB / T21473-2008.

[0067] Table 2 Performance of color pastes containing matrix resins of Examples 1-5 and Comparative Examples 1-6 .

[0068] Through Table 2 and Figure 2It can be seen that the unsaturated polyester resins obtained in Examples 1-5 of the present invention have good compatibility with other components of the color paste. The color paste containing the matrix resin has good storage stability, with no obvious change within 90-120 days, excellent coloring performance, and the coloring power is above 89%. By comparing Example 1 with Comparative Examples 1 and 2, it can be seen that in Comparative Examples 1 and 2, the molar ratio of maleic anhydride to phthalic anhydride is too low or too high, resulting in poor compatibility between the obtained unsaturated polyester and other components of the color paste. The color paste containing the matrix resin has poor storage stability, with obvious sedimentation occurring in 30 days, and poor coloring power. By comparing Example 1 with Comparative Examples 3 and 4, it can be seen that in Comparative Examples 3 and 4, the mass proportion of dibutyl phthalate in the raw materials is too low or too high, resulting in poor compatibility between the obtained unsaturated polyester and other components of the color paste. The color paste containing the matrix resin has poor storage stability, with obvious sedimentation occurring in 30 days, and poor coloring power. By comparing Example 1 with Comparative Example 5, it can be seen that in Comparative Example 5, the type of diluent is different, resulting in poor compatibility between the obtained unsaturated polyester and other components of the color paste. The color paste containing the matrix resin has poor storage stability, with obvious sedimentation occurring in 30 days, and poor coloring power. By comparing Example 1 with Comparative Example 6, it can be seen that in Comparative Example 6, no diluent is added, and the obtained unsaturated polyester is incompatible with other components of the color paste.

[0069] See Figure 2 As shown, the color powder in the matrix resin of Example 1 is significantly dissolved, and the entire matrix resin is transparent blue. No color powder particles can be seen with the naked eye, indicating good compatibility. Since Example 1 itself is colorless and transparent, after adding the blue color powder, the matrix resin itself does not interfere with the color development of the color powder, presenting a correct blue color with no deviation. After long-term placement, there is no deposition of the color powder, and there is no obvious change within 120 days, showing excellent coloring power. On the other hand, Comparative Example 2 itself is light yellow. After adding the color powder, it significantly interferes with the color development of the color powder, resulting in a large color deviation of the formed color paste. And obvious sedimentation occurs after 30 days of placement, showing poor coloring power. Comparative Example 6 performs the worst. It can be seen that the color powder is dispersed in large particle form, and there is obvious incompatibility of the color powder, resulting in unqualified quality of the produced color paste and cannot be used as the unsaturated polyester resin for formulating the color paste.

[0070] Thus, it can be seen that by controlling the molar ratio of maleic anhydride to phthalic anhydride in the synthesis raw materials of the unsaturated polyester resin, the structure of the unsaturated polyester can be regulated, especially the content and distribution of double bonds in the unsaturated polyester, so as to make the obtained unsaturated polyester resin have good compatibility with other components of the color paste. In addition, by using dibutyl phthalate as a diluent, not only can the viscosity of the unsaturated polyester be reduced, but also the flexibility of the unsaturated polyester can be increased, weakening the intermolecular interaction force, promoting the uniform dispersion of other components in the color paste matrix, making the color paste containing the unsaturated polyester resin have excellent adhesion and coloring power, and good storage stability at the same time.

[0071] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or variations can be made based on the above description. It is impossible to list all the implementation manners here. Any obvious changes or variations derived from the technical solutions of the present invention still fall within the protection scope of the present invention.

Claims

1. An unsaturated polyester resin, characterized in that The invention comprises the following raw materials in parts by weight: 70-100 parts by weight of phthalic anhydride, 80-120 parts by weight of maleic anhydride, 50-100 parts by weight of diethylene glycol, 10-40 parts by weight of ethylene glycol, 20-70 parts by weight of propylene glycol and 600-700 parts by weight of a diluent; wherein the molar ratio of maleic anhydride to phthalic anhydride is 1.2-2.6:

1.

2. An unsaturated polyester resin according to claim 1, characterized in that: The diluent is dibutyl phthalate.

3. An unsaturated polyester resin according to claim 1, characterized in that: The weight proportion of the diluent in the raw material is 60-70%.

4. An unsaturated polyester resin according to claim 1, characterized in that: The molar ratio of hydroxyl to carboxyl in the raw material is 0.84-1.

24.

5. An unsaturated polyester resin according to claim 1, characterized in that: The mass ratio of diethylene glycol, ethylene glycol and propylene glycol is 5-10:1-4:2-7.

6. The method for preparing an unsaturated polyester resin according to any one of claims 1 to 5, characterized in that: The steps include: (1) Add phthalic anhydride, maleic anhydride, diethylene glycol, ethylene glycol and propylene glycol into the reaction kettle in the order of adding liquid material first and solid material later, raise the temperature to 150-165°C, and keep it warm for 0.5-1h; (2) Continue to heat up to 190-220°C, keep warm for 2-4 hours, and when the rotational viscosity reaches 200-220cp, cool down; (3) Continue to cool down to below 120° C., add diluent and stir evenly to obtain the unsaturated polyester resin.

7. The method for preparing an unsaturated polyester resin according to claim 6, characterized in that: In step (1), the specific operation of heating is: firstly heating to 80-140°C at a heating rate of 50°C / h, and then heating to 150-165°C at a heating rate of 20°C / h after the temperature in the reactor is stable.

8. The method for preparing an unsaturated polyester resin according to claim 6, characterized in that: In step (2), the heating rate is 15-18°C / h.

9. The method for preparing an unsaturated polyester resin according to claim 6, characterized in that: In step (2), the test method of the rotational viscosity is: take a certain amount of sample, add diluent according to the mass ratio of the sample to the diluent of 3-4:7-6, and test the rotational viscosity at 25°C.

10. Use of the unsaturated polyester resin according to any one of claims 1 to 5 or the unsaturated polyester resin prepared according to any one of claims 6 to 9, characterized in that: Application in the field of color paste production.

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