Novel organic silicon modified polyester resin and preparation method thereof

Abstract

The invention discloses novel organic silicon modified polyester resin and a preparation method thereof. The novel organic silicon modified polyester resin is prepared from phenyl trichlorosilane, propyl trichlorosilane, medium molecular weight polyester resin, a catalyst, an organic solvent and other raw materials. The phenyl propyl silicon resin prepolymer prepared from the phenyl trichlorosilane and the propyl trichlorosilane with the preferable dosage is subjected to graft copolymerization with the medium-molecular-weight polyester resin to obtain the novel organic silicon modified polyester resin with excellent performance. The synthesized novel organic silicon modified polyester resin has good mechanical properties, good electrical insulation properties, good heat resistance, good weather resistance and the like, and has very good technical effects. The coating can be used for insulating and flame-retardant coating of a new energy electric vehicle battery.

Description

Technical Field

[0001] The invention belongs to the field of polymer resins, and specifically relates to a novel organosilicon-modified polyester resin having excellent mechanical properties, electrical insulation properties, heat resistance, flame retardancy and weather resistance, and a preparation method thereof. Background Art

[0002] At present, methyl silicone resin and methylphenyl silicone resin are commonly used in the market, but phenylpropyl silicone resin is relatively rare in the market. Propylphenyl silicone resin has better solubility than methyl silicone resin and methylphenyl silicone resin, and better compatibility with other organic resins. The propyl group has a longer chain than the methyl group, has better flexibility, can be made into a solid product, and is more environmentally friendly. Therefore, the present invention provides a polyester resin modified by phenylpropyl silicone resin. Summary of the invention

[0003] Purpose of the invention: The present invention adopts a preferred amount of monophenyltrichlorosilane and propyltrichlorosilane to prepare a phenylpropyl silicone resin prepolymer and a polyester resin for graft copolymerization to obtain a novel organosilicon-modified polyester resin with excellent performance. The novel organosilicon-modified polyester resin has good mechanical properties, good electrical insulation properties, good heat resistance, good flame retardancy, good weather resistance, etc. Another purpose of the present invention is to provide a curing method for the modified resin.

[0004] Technical solution: To achieve the above purpose, the technical solution adopted by the present invention is:

[0005] A new type of organosilicon modified polyester resin is made from the following raw materials:

[0006] Monophenyltrichlorosilane, propyltrichlorosilane, medium molecular weight polyester resin, catalyst, organic solvent.

[0007] As a preferred embodiment, in the novel organosilicon-modified polyester resin described above, the molar ratio of monophenyltrichlorosilane to propyltrichlorosilane is 2.5:1.

[0008] As a preferred embodiment, the novel organosilicon-modified polyester resin described above, the novel organosilicon-modified polyester resin, and the medium molecular weight polyester resin include models 3101-7 and 3101-8 medium molecular weight polyester resins;

[0009] The medium molecular weight polyester resin 3101-7 is prepared by the following method: 350 g of trimethylolpropane, 100 g of neopentyl glycol, 500 g of isophthalic acid, and 130 g of pentaerythritol are put into a three-necked flask, heated and heated, and stirred after the materials are completely melted, and the temperature is continued to rise. When the temperature of the distillation head reaches 90-100° C., liquid begins to flow out, and the temperature of the three-necked flask is maintained at 160-170° C. As the reaction proceeds, the amount of liquid increases, and the reaction temperature rises to 180-190° C., and the reaction is continued. When the temperature rises to 210° C., a sample is taken to measure the acid value. When the acid value is lower than 20 mgKOH / g, propylene glycol methyl ether acetate is added to dilute to obtain a solid content of 60%;

[0010] The medium molecular weight polyester resin 3101-8 is prepared by the following method: 380 g of trimethylolpropane, 120 g of neopentyl glycol, and 580 g of isophthalic acid are put into a three-necked flask, heated and heated, and stirred after the materials are completely melted, and the temperature is continued to rise. When the temperature of the distillation head reaches 90-100° C., liquid begins to flow out, and the temperature of the three-necked flask is maintained at 160-170° C. As the reaction proceeds, the amount of liquid increases, and the reaction temperature rises to 180-190° C. The reaction is continued. When the temperature rises to 210° C., a sample is taken to measure the acid value. When the acid value is lower than 20 mgKOH / g, propylene glycol methyl ether acetate is added to dilute to obtain a solid content of 60%.

[0011] As a preferred embodiment, in the novel organosilicon-modified polyester resin described above, the catalyst is butyl titanate or isopropyl titanate.

[0012] As a preferred embodiment, in the novel organosilicon-modified polyester resin described above, the organic solvent comprises propylene glycol methyl ether acetate (PMA) and n-butanol.

[0013] The preparation method of the novel organosilicon-modified polyester resin of the present invention comprises the following steps:

[0014] (1) Preparation of phenylpropyl silicone resin prepolymer

[0015] The two raw materials of monophenyl trichlorosilane and propyl trichlorosilane are hydrolyzed in xylene, washed with water after the reaction, and then concentrated to obtain phenyl propyl silicone resin prepolymer.

[0016] (2) Preparation of silicone-modified polyester resin

[0017] The phenylpropyl silicone resin prepolymer prepared in step (1) and the polyester resin are subjected to a graft copolymerization reaction in a PMA and n-butanol solution under the action of a catalyst to obtain the product.

[0018] As a preferred embodiment, the preparation method of the novel organosilicon-modified polyester resin comprises the following steps:

[0019] Step (1) Preparation of phenylpropyl silicone resin prepolymer

[0020] Separately take 80g of propyltrichlorosilane, 180g of monophenyltrichlorosilane, and 420g of xylene, mix well, transfer to a dropping funnel, and dropwise add to a hydrolysis reaction bottle containing 1500g of water at 7-20°C for hydrolysis reaction. The hydrolysis is completed in 3 hours, and the mixture is allowed to stand for stratification, the lower layer of acid water is separated, and the mixture is transferred to a water washing bottle and washed with 2000g of water; the mixture is washed with water 6 times, and the mixture is transferred to a concentration condensation bottle and vacuumed for concentration. The solid content of 60% phenylpropyl silicone resin prepolymer is obtained by concentration, and the mixture is set aside;

[0021] Step (2) Preparation of silicone-modified polyester resin

[0022] In a three-necked flask, add 250 g of the phenylpropyl silicone resin prepolymer with a solid content of 60% prepared in step (1), further add 30 g of propylene glycol methyl ether acetate, 30 g of n-butanol and 250 g of a medium molecular weight polyester resin 3101-8 with a solid content of 60%, and then add 0.8 g of butyl titanate. After reacting at a temperature of 130-150° C. for 4 hours, take a sample to measure the gelation time. If the gelation time exceeds 30 seconds, continue the reaction. After half an hour, take a sample to measure the gelation time again. When the gelation time reaches 15-30 seconds / 230° C., the reaction is completed and poured out while hot.

[0023] As a preferred embodiment, the method for preparing the novel organosilicon-modified polyester resin described above comprises the following steps:

[0024] Step (1) Preparation of phenylpropyl silicone resin prepolymer

[0025] Take 90g of propyltrichlorosilane, 180g of monophenyltrichlorosilane and 420g of xylene respectively, mix them well, transfer them to a high-level tank, and add them dropwise to a hydrolysis reaction bottle containing 1500g of water at 7-20°C for hydrolysis reaction. The hydrolysis is completed in 3 hours, stand for stratification, separate the lower layer of acid water, transfer them to a water washing bottle and add 2000g of water for washing; wash them with water 6 times, transfer them to a concentration condensation bottle and evacuate to concentrate, and concentrate to obtain a phenylpropyl silicone resin prepolymer with a solid content of 60%, which is set aside;

[0026] Step (2) Preparation of silicone-modified polyester resin

[0027] In a three-necked flask, add 300 g of the phenylpropyl silicone resin prepolymer with a solid content of 60% prepared in step (1), further add 30 g of propylene glycol methyl ether acetate, 30 g of n-butanol and 250 g of a medium molecular weight polyester resin 3101-8 with a solid content of 60%, and then add 0.8 g of butyl titanate. After reacting at a temperature of 130-150° C. for 4 hours, take a sample to measure the gelation time. If the gelation time exceeds 30 seconds, continue the reaction. After half an hour, take a sample to measure the gelation time again. When the gelation time reaches 15-30 seconds / 230° C., the reaction is completed and poured out while hot.

[0028] In the above preparation method, the hydrolysis temperature in step (1) is controlled relatively low, generally controlled at 7-20°C, which is better, with high yield, good appearance, and uniform molecular weight distribution. The hydrolysis stirring speed also has a great influence on the reaction. When the stirring speed is faster, the yield is higher and the by-products are less.

[0029] The ratio of xylene to the two monomers is also critical. When the amount of xylene is slightly larger than the total amount of the two monomers, the yield is higher, the finished product has a good appearance, and the molecular weight distribution is narrow. The amount of water used for hydrolysis is recommended to be 1.5 to 2 times the total amount of xylene and the two monomers. The number of water washes is recommended to be at least 6 times to wash away the residual acid as much as possible, so that the electrical properties of the finished product are good. The ratio of monophenyltrichlorosilane to propyltrichlorosilane is best controlled at 2.5:1, so that the product has a good appearance, high yield, and good compatibility with organic resins.

[0030] The inventive technical features of the present invention include:

[0031] 1. The present invention uses two raw materials, monophenyltrichlorosilane and propyltrichlorosilane, and xylene to hydrolyze, wash, concentrate and condense to obtain the product.

[0032] The present invention screens different amounts of monophenyltrichlorosilane and propyltrichlorosilane, and prepares propylphenyl silicone resin according to the above method under the condition that other conditions remain unchanged. The results are shown in Table 1. The yields of the synthesis reaction of monophenyltrichlorosilane and propyltrichlorosilane with different usage ratios are different. Different results can be obtained by adjusting the ratio of monophenyltrichlorosilane and propyltrichlorosilane. It is found that the final product yield is the highest when the mass ratio is 2.5:1.

[0033] Table 1

[0034] Benzenetrichloride:propyltrichloride (mass ratio) 3：1 2.5：1 2：1 1.5：1 Yield % 70 90 80 75 in conclusion Lower high Higher generally .

[0035] 2. During the experiment, when other conditions remain unchanged, it is found that the hydrolysis temperature is controlled at a relatively low level, generally controlled at 10-15°C, with high yield, good appearance, and uniform molecular weight distribution. See Table 2. The hydrolysis stirring speed has a great influence on the reaction. When the stirring speed is faster, the yield is higher and the by-products are less.

[0036] Table 2 Effect of hydrolysis temperature on yield

[0037] Hydrolysis temperature 1-5℃ 5-10℃ 10-15℃ 15-20℃ 20-25℃ Intermediate yield 80％ 85％ 90％ 85％ 75％ in conclusion generally Higher high Higher Low .

[0038] 3. During the experiment, when other conditions remain unchanged, the ratio of xylene to the two monomers in the raw material of the present invention is also critical. The amount of xylene slightly greater than the total amount of the two monomers has a higher yield, a good finished product appearance, and a narrow molecular weight distribution. As shown in Table 3, the effect of xylene addition on the appearance and yield of the finished product, the amount of water used for hydrolysis is 1.5 to 2 times the sum of the amount of xylene and the two monomers. It is recommended to wash at least 6 times to wash the residual acid as clean as possible, so that the electrical properties of the resulting finished product are good.

[0039] Table 3

[0040]

[0041] It can be seen from Table 3 that when the ratio of xylene to the total amount of monomer is 2:1, the appearance and yield are optimal. And the more xylene there is, the higher the yield is not necessarily the case. Too much xylene will generate more impurities, which will reduce the yield and waste materials.

[0042] 4. In the second step, the reaction between the propyl phenyl silicone resin prepolymer and the polyester resin will produce different results when different polyester resins are used. The propyl phenyl silicone resin uses the best formula to make the prepolymer, and the ratio of phenyl propyl silicone resin to polyester resin remains unchanged at 5:5. The following is the result table 4 obtained by using different polyester resins and phenyl propyl silicone resins to react.

[0043] Table 4

[0044]

[0045] From the above, it can be seen that after comprehensive consideration, medium molecular weight polyester resin 3101-8 is the best choice. It leads in all aspects of performance.

[0046] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0047] The invention adopts a phenylpropyl silicone resin prepolymer prepared by hydrolyzing monophenyltrichlorosilane and propyltrichlorosilane in preferred amounts, and then graft-copolymerizes the prepolymer with a polyester resin to obtain a novel organosilicon-modified polyester resin with excellent performance.

[0048] The novel organosilicon-modified polyester resin prepared by the present invention has good mechanical properties, good electrical insulation properties, good heat resistance, good flame retardant properties, good weather resistance, etc. It can also be used to make coating agents for the electronic and electrical industry, coating agents for the insulation industry, insulating flame retardant coatings, high temperature resistant powder coatings, weather resistant coatings, etc. It has good application prospects and high use value, and is widely used in new energy batteries, electronic and electrical industry, chip industry, insulation industry, and high-performance coating industry. DETAILED DESCRIPTION

[0049] The embodiments of the present invention will be described in detail below in conjunction with the examples. If the specific conditions are not specified in the examples, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be obtained commercially. The experimental methods in the following examples that do not specify the specific conditions are usually carried out according to conventional conditions or the conditions provided by the manufacturer.

[0050] Example 1

[0051] A method for preparing a novel organosilicon-modified epoxy resin comprises the following steps:

[0052] Step (1) Preparation of phenylpropyl silicone resin prepolymer

[0053] Take 100g of propyltrichlorosilane, 250g of monophenyltrichlorosilane, and 700g of xylene, mix well, transfer to a dropping funnel, add dropwise to a reaction bottle containing 1500g of water at 7-20°C for hydrolysis reaction, control the stirring speed to 70 rpm, and complete the hydrolysis in 3 hours. Let stand for stratification, separate the lower layer of acid water, transfer to a water washing bottle, add 2000g of water, wash with water 6 times, transfer to a concentration condensation bottle, evacuate and concentrate, and concentrate to obtain 260g of 60% solid content phenylpropyl silicone resin prepolymer for standby use;

[0054] Step (2) Preparation of silicone-modified polyester resin

[0055] Add 250g of the phenylpropyl silicone resin prepolymer with a solid content of 60% prepared in step (1) into a three-necked flask, add 30g of PMA, 30g of n-butanol and 250g of 3101-7 polyester resin (60% solid content), and then add 0.8g of butyl titanate. After reacting at a temperature of 150°C for 4 hours, take a sample to measure the gelation time. If the gelation time exceeds 30 seconds, continue to react. Take a sample again to measure the gelation time after half an hour. When the gelation time reaches 15-30 seconds / 230°C, the reaction is completed. Pour it out while it is hot. The softening point is 55 degrees. Appearance: light yellow transparent solid.

[0056] Example 2

[0057] A method for preparing a novel organosilicon-modified polyester resin comprises the following steps:

[0058] Step (1) Preparation of phenylpropyl silicone resin prepolymer

[0059] Separately take 100g of propyltrichlorosilane, 250g of monophenyltrichlorosilane, and 700g of xylene, mix well, transfer to a dropping funnel, and dropwise add to a hydrolysis reaction bottle containing 1500g of water at 7-20°C for hydrolysis reaction, control the stirring speed to 70 rpm, and complete the hydrolysis in 3 hours. Let stand for stratification, separate the lower layer of acid water, transfer to a water washing bottle and add 2000g of water for washing; wash with water 6 times, transfer to a concentration condensation bottle and evacuate to concentrate, and concentrate to obtain 260g of phenylpropyl silicone resin prepolymer with a solid content of 60%, which is set aside;

[0060] Step (2) Preparation of silicone-modified polyester resin

[0061] Add 250g of the phenylpropyl silicone resin prepolymer with a solid content of 60% prepared in step (1) into a three-necked flask, add 30g of PMA, 30g of n-butanol, and then add 250g of 3101-8 polyester resin (60% solid content) and 0.8g of isopropyl titanate. After reacting at a temperature of 150°C for 4 hours, take a sample to measure the gelation time. If the gelation time exceeds 30 seconds, continue to react. Take a sample again to measure the gelation time after half an hour. When the gelation time reaches 15-30 seconds / 230°C, the reaction is completed and poured out while hot. The softening point is 60 degrees. Appearance: light yellow transparent solid.

[0062] Embodiment 3 A method for preparing a novel organosilicon-modified polyester resin comprises the following steps:

[0063] Step (1) Preparation of phenylpropyl silicone resin prepolymer

[0064] Take 100g of propyltrichlorosilane, 250g of monophenyltrichlorosilane and 700g of xylene respectively, mix them well, transfer them to a high-level tank, and add them dropwise to a hydrolysis reaction bottle containing 1500g of water at 7-20°C for hydrolysis reaction. Control the stirring speed to 70 rpm. The hydrolysis is completed in 3 hours. Let it stand for stratification, separate the lower layer of acid water, transfer it to a water washing bottle and add 2000g of water for washing; wash it with water 6 times, transfer it to a concentration condensation bottle and evacuate it for concentration, and concentrate to obtain 260g of phenylpropyl silicone resin prepolymer with a solid content of 60% for standby use;

[0065] Step (2) Preparation of silicone-modified polyester resin

[0066] Add 300g of 60% solid phenylpropyl silicone resin prepolymer, 60g of PMA, 250g of 3101-8 polyester resin, 0.5g of zinc octanoate, and 0.5g of zinc naphthoate into a three-necked flask. The reaction temperature is 155°C. Take a sample after 4 hours to measure the gelation time. If the gelation time exceeds 30 seconds, continue the reaction. Take a sample again after half an hour to measure the gelation time. When the gelation time reaches 15-30 seconds / 230°C, the reaction is over and pour it out while it is hot. The softening point is 62 degrees. Appearance: light yellow transparent solid.

[0067] Example 4 Performance Test

[0068] The organosilicon-modified polyester resin prepared in Examples 1 to 3 above was used for performance testing by air spraying with the varnish film thickness controlled at about 20-35 μm. The specific test results are shown in Table 5 below.

[0069] Table 5 Performance test results

[0070]

[0071]

[0072] Comparative performance tests show that Example 3 has the best comprehensive performance, but the cost is relatively high, and Example 2 is preferred, with moderate cost and performance not inferior to Example 3. In summary, Example 2 can be promoted and applied, and has good economic and practical value.

[0073] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A novel silicone-modified polyester resin, characterized in that: It is made from the following raw materials: Monophenyltrichlorosilane, propyltrichlorosilane, medium molecular weight polyester resin, catalyst, organic solvent.

2. The novel silicone-modified polyester resin according to claim 1, characterized in that: The molar ratio of monophenyltrichlorosilane to propyltrichlorosilane is 2.5:

1.

3. The novel organosilicon-modified polyester resin according to claim 1, characterized in that: The medium molecular weight polyester resin includes models 3101-7 and 3101-8 medium molecular weight polyester resin; The medium molecular weight polyester resin 3101-7 is prepared by the following method: 350 g of trimethylolpropane, 100 g of neopentyl glycol, 500 g of isophthalic acid, and 130 g of pentaerythritol are put into a three-necked flask, heated and heated, and stirred after the materials are completely melted, and the temperature is continued to rise. When the temperature of the distillation head reaches 90-100° C., liquid begins to flow out, and the temperature of the three-necked flask is maintained at 160-170° C. As the reaction proceeds, the amount of liquid increases, and the reaction temperature rises to 180-190° C., and the reaction is continued. When the temperature rises to 210° C., a sample is taken to measure the acid value. When the acid value is lower than 20 mgKOH / g, propylene glycol methyl ether acetate is added to dilute to obtain a solid content of 60%; The medium molecular weight polyester resin 3101-8 is prepared by the following method: 380 g of trimethylolpropane, 120 g of neopentyl glycol, and 580 g of isophthalic acid are put into a three-necked flask, heated and heated, and stirred after the materials are completely melted, and the temperature is continued to rise. When the temperature of the distillation head reaches 90-100° C., liquid begins to flow out, and the temperature of the three-necked flask is maintained at 160-170° C. As the reaction proceeds, the amount of liquid increases, and the reaction temperature rises to 180-190° C. The reaction is continued. When the temperature rises to 210° C., a sample is taken to measure the acid value. When the acid value is lower than 20 mgKOH / g, propylene glycol methyl ether acetate is added to dilute to obtain a solid content of 60%.

4. The novel silicone-modified polyester resin according to claim 1, characterized in that: The catalyst is butyl titanate or isopropyl titanate.

5. The novel organosilicon-modified polyester resin according to claim 1, characterized in that: The organic solvent includes propylene glycol methyl ether acetate and n-butanol.

6. The method for preparing the novel silicone-modified polyester resin according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) Preparation of phenylpropyl silicone resin prepolymer The two raw materials of monophenyl trichlorosilane and propyl trichlorosilane are subjected to hydrolysis reaction in xylene, and after the reaction is completed, the mixture is washed with water and then concentrated to obtain a phenyl propyl silicone resin prepolymer; (2) Preparation of silicone-modified polyester resin The phenylpropyl silicone resin prepolymer prepared in step (1) and the medium molecular weight polyester resin are subjected to a graft copolymerization reaction in a propylene glycol methyl ether acetate and n-butanol solution under the action of a catalyst to obtain the product.

7. The method for preparing the novel organosilicon-modified polyester resin according to claim 6, characterized in that: The graft copolymerization reaction temperature in step (2) is controlled at 130-150° C., the reaction time is controlled at 4-8 hours, and the gelation time is measured during the reaction to control the end point. The gelation time is controlled at 15-30 seconds / 230° C.

8. The method for preparing the novel organosilicon-modified polyester resin according to claim 6, characterized in that: The following steps are involved: Step (1) Preparation of phenylpropyl silicone resin prepolymer Take 100g of propyltrichlorosilane, 250g of monophenyltrichlorosilane, and 700g of xylene, mix well, transfer to a dropping funnel, add dropwise to a reaction bottle containing 1500g of water at 7-20°C for hydrolysis reaction, control the stirring speed to 70 rpm, and complete the hydrolysis in 3 hours. Let stand for stratification, separate the lower layer of acid water, transfer to a water washing bottle, add 2000g of water, wash with water 6 times, transfer to a concentration condensation bottle, evacuate and concentrate, and concentrate to obtain 260g of 60% solid content phenylpropyl silicone resin prepolymer for standby use; Step (2) Preparation of silicone-modified polyester resin In a three-necked flask, add 250 g of the phenylpropyl silicone resin prepolymer with a solid content of 60% prepared in step (1), further add 30 g of propylene glycol methyl ether acetate, 30 g of n-butanol and 250 g of 60% solid content 3101-7 polyester resin, and then add 0.8 g of butyl titanate. After reacting at a temperature of 150° C. for 4 hours, take a sample to measure the gelation time. If the gelation time exceeds 30 seconds, continue the reaction. After half an hour, take a sample to measure the gelation time again. When the gelation time reaches 15-30 seconds / 230° C., the reaction is completed.

9. The method for preparing the novel organosilicon-modified polyester resin according to claim 6, characterized in that: The following steps are involved: Step (1) Preparation of phenylpropyl silicone resin prepolymer Take 100g of propyltrichlorosilane, 250g of monophenyltrichlorosilane and 700g of xylene respectively, mix them well, transfer them into a dropping funnel, add them dropwise into a hydrolysis reaction bottle containing 1500g of water at 7-20°C for hydrolysis reaction, control the stirring speed to 70 rpm, and complete the hydrolysis in 3 hours. Let it stand for stratification, separate the lower layer of acid water, transfer them into a washing bottle and add 2000g of water for washing; Wash with water for 6 times, transfer to a concentration condensation bottle and evacuate to concentrate, and concentrate to obtain 260 g of phenylpropyl silicone resin prepolymer with a solid content of 60%, which is set aside; Step (2) Preparation of silicone-modified polyester resin In a three-necked flask, add 250 g of the phenylpropyl silicone resin prepolymer with a solid content of 60% prepared in step (1), further add 30 g of propylene glycol methyl ether acetate, 30 g of n-butanol, and then add 250 g of 3101-8 polyester resin with a solid content of 60% and 0.8 g of isopropyl titanate. After reacting at a temperature of 150° C. for 4 hours, take a sample to measure the gelation time. If the gelation time exceeds 30 seconds, continue the reaction. After half an hour, take a sample to measure the gelation time again. When the gelation time reaches 15-30 seconds / 230° C., the reaction is completed.

10. The method for preparing the novel organosilicon-modified polyester resin according to claim 6, characterized in that: The following steps are involved: Step (1) Preparation of phenylpropyl silicone resin prepolymer Take 100g of propyltrichlorosilane, 250g of monophenyltrichlorosilane and 700g of xylene respectively, mix them well, transfer them to a high-level tank, and add them dropwise to a hydrolysis reaction bottle containing 1500g of water at 7-20°C for hydrolysis reaction. Control the stirring speed to 70 rpm. The hydrolysis is completed in 3 hours. Let it stand for stratification, separate the lower layer of acid water, transfer them to a water washing bottle and add 2000g of water for washing; Wash with water for 6 times, transfer to a concentration condensation bottle and evacuate to concentrate, and concentrate to obtain 260 g of phenylpropyl silicone resin prepolymer with a solid content of 60% for use; Step (2) Preparation of silicone-modified polyester resin In a three-necked flask, add 300g of 60% solid phenylpropyl silicone resin prepolymer, 60g of propylene glycol methyl ether acetate, and then add 250g of 3101-8 polyester resin, 0.5g of zinc octoate, and 0.5g of zinc naphthoate. The reaction temperature is 155°C. After 4 hours, take a sample to measure the gelation time. If the gelation time exceeds 30 seconds, continue the reaction. After half an hour, take a sample to measure the gelation time again. When the gelation time reaches 15-30 seconds / 230°C, the reaction is completed.

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