阅读说明：本技术 一种对苯二甲酸型不饱和聚酯树脂及其制备方法 (Terephthalic acid type unsaturated polyester resin and preparation method thereof ) 是由 徐贵红 黎旦光 刘泽丰 梁正权 苏伟麟 于 2020-07-31 设计创作，主要内容包括：本发明公开了一种对苯二甲酸型不饱和聚酯树脂,其通过三步法工艺合成,反应体系包括以下重量百分比的组分：第一步,对苯二甲酸14～20％,甲基丙二醇18～23％,三羟甲基丙烷3-4％,催化剂0.02％；第二步,顺酐33～40％,二元醇19～21％,抗氧剂0.06-0.07％；第三步,顺酐3％,阻聚剂0.02-0.03％。本发明采用三步法工艺合成对苯二甲酸型SMC/BMC不饱和聚酯树脂,不需要加压工艺,饱和二元酸全部采用对苯二甲酸,不用除对苯二甲酸之外的其他饱和二元酸,可以合成出与苯乙烯相容性好、树脂透明度好、物理机械性能良好的聚酯树脂。该树脂用于SMC/BMC产品,可以提高耐热、机械强度等性能。(The invention discloses a terephthalic acid type unsaturated polyester resin, which is synthesized by a three-step process, wherein a reaction system comprises the following components in percentage by weight: the method comprises the following steps of firstly, 14-20% of terephthalic acid, 18-23% of methyl propylene glycol, 3-4% of trimethylolpropane and 0.02% of a catalyst; step two, 33-40% of maleic anhydride, 19-21% of dihydric alcohol and 0.06-0.07% of antioxidant; thirdly, 3 percent of maleic anhydride and 0.02 to 0.03 percent of polymerization inhibitor. The invention adopts a three-step process to synthesize the terephthalic acid type SMC/BMC unsaturated polyester resin, does not need a pressurization process, adopts terephthalic acid as the saturated dibasic acid, does not use other saturated dibasic acids except terephthalic acid, and can synthesize the polyester resin with good compatibility with styrene, good resin transparency and good physical and mechanical properties. The resin is used for SMC/BMC products, and can improve the performances such as heat resistance, mechanical strength and the like.)

1. The terephthalic acid type unsaturated polyester resin is characterized by being synthesized by a three-step process, wherein a reaction system comprises the following components in percentage by weight: the method comprises the following steps of firstly, 14-20% of terephthalic acid, 18-23% of methyl propylene glycol, 3-4% of trimethylolpropane and 0.02% of a catalyst; step two, 33-40% of maleic anhydride, 19-21% of dihydric alcohol and 0.06-0.07% of antioxidant; thirdly, 3 percent of maleic anhydride and 0.02 to 0.03 percent of polymerization inhibitor.

2. The terephthalic acid type unsaturated polyester resin according to claim 1, further comprising styrene in an amount of 30 to 40% based on the sum of styrene and the weight of the reaction system.

3. The terephthalic acid type unsaturated polyester resin according to claim 2, wherein the styrene content is 30 to 31%.

4. The terephthalic-type unsaturated polyester resin according to claim 1, wherein the catalyst is monobutyltin oxide.

5. The terephthalic acid type unsaturated polyester resin according to claim 1, wherein the antioxidant is triphenyl phosphite.

6. The terephthalic-type unsaturated polyester resin according to claim 1, wherein the polymerization inhibitor is methyl hydroquinone.

7. The method for producing the terephthalic acid type unsaturated polyester resin according to any one of claims 1 to 6, characterized by comprising the steps of:

step 1: adding the wet material and the auxiliary agent in the first step, stirring uniformly, adding the dry material under stirring, after the feeding is finished, supplying nitrogen, heating, controlling the distillation temperature to be not more than 103 ℃, controlling the highest material temperature to be not more than 215 ℃, stopping heating and cooling when the sampled material is transparent and the acid value is less than 5 mgKOH/g;

step 2: when the temperature of the material is reduced to 180 ℃, adding the wet material and the auxiliary agent in the second step, adding the dry material, heating after the material is added, controlling the distillation temperature to be not more than 102 ℃, controlling the highest temperature of the material to be not more than 205 ℃, increasing the nitrogen amount when the distillation temperature is lower than 90 ℃, reacting at the constant temperature of 205 ℃, controlling the viscosity of the polyester as the end point when the constant temperature reaction is carried out until the acid value is less than 15mgKOH/g and the viscosity of the polyester is 40-42P/120 ℃, and starting to reduce the temperature;

and step 3: when the temperature of the materials is reduced to 180 ℃, adding the polymerization inhibitor and the dry materials in the third step, keeping the temperature at 175-180 ℃ for 1 hour, then reducing the temperature, and diluting with styrene.

8. The method of claim 7, wherein the dilution temperature in step 3 is not more than 85 ℃.

Technical Field

The invention belongs to the field of high polymer materials, and particularly relates to terephthalic acid type unsaturated polyester resin and a preparation method thereof.

Background

The unsaturated polyester resin is widely applied to industries such as industry, agriculture, national defense and building, especially SMC, BMC and other mold pressure reinforced unsaturated polyesters, and has the advantages of high strength and stable part size, so the unsaturated polyester resin is developed quickly. At present, the consumption of polyester in the polyester glass fiber reinforced plastics accounts for 70 to 80 percent of the total consumption of polyester. At present, unsaturated polyester resin commonly used in chemical enterprises for SMC/BMC matrix resin is mainly o-benzene unsaturated polyester, p-benzene unsaturated polyester resin is used as matrix resin, the wetting property with glass fiber is good, and the heat resistance, water resistance and chemical resistance are improved, so that the p-benzene unsaturated polyester resin is proposed to be applied to SMC/BMC.

The p-benzene type unsaturated polyester resin is a new product developed successfully in recent years. The terephthalic acid with a linear structure replaces phthalic acid, carboxyl of the terephthalic acid is positioned on para position of a benzene ring, interaction is small, chemical properties are stable, and therefore the polyester macromolecular structure is symmetrical and arranged orderly, and good electrical property, mechanical property and heat resistance are shown. The chemical resistance and the heat resistance of the polyester resin are particularly outstanding, which are superior to the m-benzene unsaturated polyester resin and are more incomparable with the o-benzene unsaturated polyester resin, and the price of the polyester resin is lower than that of the m-benzene unsaturated polyester resin and is equivalent to that of the o-benzene unsaturated polyester resin.

However, in the process of synthesizing the p-benzene type unsaturated polyester resin, the carboxyl of the terephthalic acid is positioned at the para position of a benzene ring, the interaction is small, the chemical property is relatively stable, the reaction activity with the dihydric alcohol is poor, the reaction can be carried out under the conditions of taking strong acid as a catalyst, pressurizing at high temperature and the like, the reaction time is also long, the compatibility of the synthesized polyester and styrene is poor, and the synthesized polyester is easy to delaminate and loses the use value. In the process of synthesizing the p-benzene unsaturated resin, a two-step method is generally used, pressure synthesis is required, the process has difficulty for many resin factories, the equipment requirement is high, and the alcohol synthesized in the first step has too low boiling point, and if the alcohol is not pressurized, the alcohol is difficult to completely react with terephthalic acid.

Disclosure of Invention

The invention aims to solve the technical problems and provide a terephthalic acid type unsaturated polyester resin which has good compatibility with styrene, good resin transparency and good mechanical and physical properties.

In order to realize the aim, the invention provides terephthalic acid type unsaturated polyester resin which is synthesized by a three-step normal pressure process, wherein a reaction system comprises the following components in percentage by weight: the method comprises the following steps of firstly, 14-20% of terephthalic acid, 18-23% of methyl propylene glycol, 3-4% of trimethylolpropane and 0.02% of a catalyst; step two, 33-40% of maleic anhydride, 19-21% of dihydric alcohol and 0.06-0.07% of antioxidant; thirdly, 3 percent of maleic anhydride and 0.02 to 0.03 percent of polymerization inhibitor.

Preferably, the terephthalic-type unsaturated polyester resin of the present invention further comprises styrene in an amount of 30 to 40% based on the sum of styrene and the weight of the reaction system. More preferably, the styrene content is from 30% to 31%. Preferably, the copper isooctanoate also contains 0.01 percent of the total weight of copper isooctanoate.

Preferably, the catalyst is monobutyltin oxide.

Preferably, the antioxidant is triphenyl phosphite.

Preferably, the polymerization inhibitor is methyl hydroquinone.

Preferably, the glycol is ethylene glycol or propylene glycol or a mixture of both.

On the other hand, the invention also provides a preparation method of the terephthalic acid type unsaturated polyester resin, which comprises the following steps:

step 1: adding the wet material and the auxiliary agent in the first step, stirring uniformly, adding the dry material under stirring, after the feeding is finished, supplying nitrogen, heating, controlling the distillation temperature to be not more than 103 ℃, controlling the highest material temperature to be not more than 215 ℃, stopping heating and cooling when the sampled material is transparent and the acid value is less than 5 mgKOH/g;

step 2: when the temperature of the material is reduced to 180 ℃, adding the wet material and the auxiliary agent in the second step, adding the dry material, heating after the material is added, controlling the distillation temperature to be not more than 102 ℃, controlling the highest temperature of the material to be not more than 205 ℃, increasing the nitrogen amount when the distillation temperature is lower than 90 ℃, reacting at the constant temperature of 205 ℃, controlling the viscosity of the polyester as the end point when the constant temperature reaction is carried out until the acid value is less than 15mgKOH/g and the viscosity of the polyester is 40-42P/120 ℃, and starting to reduce the temperature;

and step 3: when the temperature of the materials is reduced to 180 ℃, adding the polymerization inhibitor and the dry materials in the third step, keeping the temperature at 175-180 ℃ for 1 hour, then reducing the temperature, and diluting with styrene.

Preferably, when the dilution is carried out in the step 3, the dilution temperature does not exceed 85 ℃.

The invention adopts a three-step process to synthesize the terephthalic acid type SMC/BMC unsaturated polyester resin, does not need a pressurization process, adopts terephthalic acid as the saturated dibasic acid, does not use other saturated dibasic acids except terephthalic acid, and can synthesize the polyester resin with good styrene compatibility and good resin transparency. The resin is used for SMC/BMC products, and can improve the performances such as heat resistance, water resistance and the like.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Unless otherwise specified, the instruments or reagents used in the examples are conventional reagents or instruments in the art, and are conventional products available on the market. Unless otherwise stated, the specific experimental procedures mentioned herein are understood or known by those skilled in the art based on common general knowledge or conventional technical means, and are not described in detail. For the sake of brevity, the parameters of the procedures, steps and equipment used are not described in detail in part of the procedures, it being understood that these are well known to those skilled in the art and are reproducible.