阅读说明：本技术 一种硅改性树脂的制备方法和一种硅改性树脂 (Preparation method of silicon modified resin and silicon modified resin ) 是由 雷焕虎 朱洪江 贺辉荣 冯杰超 李淑艳 于 2020-12-11 设计创作，主要内容包括：一种硅改性树脂的制备方法,包括以下步骤:S1:称取含羟基树脂、硅氧烷低聚物、催化剂和溶剂；S2：将所述含羟基树脂、硅氧烷低聚物和部分所述溶剂加入同一反应容器中,加热并保温；S3：加入所述催化剂和部分溶剂,在加热条件下反应；S4：降温,得到硅改性树脂。所述硅改性树脂的制备方法中,含羟基树脂中的端羟基与含有甲氧基或乙氧基的硅氧烷低聚物在催化剂作用下发生酯交换反应,生成侧链含有聚硅氧烷的硅改性树脂。所述硅改性树脂具有较低的表面张力,使用所述硅改性树脂制备的涂料可用于涂布形成涂层,涂层具有良好的自流平性、防缩孔性、鲜映性及良好的涂层通透性,在100℃～150℃温度范围内具有重涂性。(S1, weighing hydroxyl-containing resin, siloxane oligomer, catalyst and solvent; s2: adding the hydroxyl-containing resin, the siloxane oligomer and part of the solvent into the same reaction vessel, heating and preserving heat; s3: adding the catalyst and part of the solvent, and reacting under heating; s4: and cooling to obtain the silicon modified resin. In the preparation method of the silicon modified resin, the terminal hydroxyl in the hydroxyl-containing resin and siloxane oligomer containing methoxyl or ethoxyl are subjected to ester exchange reaction under the action of a catalyst to generate the silicon modified resin with polysiloxane contained in the side chain. The silicon modified resin has lower surface tension, the coating prepared by using the silicon modified resin can be used for coating to form a coating, and the coating has good self-leveling property, anti-shrinkage property, distinctness of image, good coating permeability and repairability within the temperature range of 100-150 ℃.)

1. A preparation method of silicon modified resin is characterized by comprising the following steps:

the method comprises the following steps:

s1, weighing hydroxyl-containing resin, siloxane oligomer, catalyst and solvent;

s2: adding the hydroxyl-containing resin, the siloxane oligomer and part of the solvent into the same reaction vessel, heating and preserving heat;

s3: adding the catalyst and part of the solvent, and reacting under heating;

s4: and cooling to obtain the silicon modified resin.

2. The method for preparing a silicon modified resin according to claim 1, wherein:

the content of the hydroxyl resin is 60-80%, the content of the siloxane oligomer is 2-5%, the content of the solvent is 15-35%, and the content of the catalyst is 0.1-1%.

3. The method for preparing a silicon modified resin according to claim 1, wherein:

the hydroxyl content of the hydroxyl-containing resin is 3-6%.

4. The method for preparing a silicon modified resin according to claim 1, wherein:

the siloxane oligomer contains 20-50% of methoxyl or ethoxyl and has a molecular weight of 300-1000.

5. The method for preparing a silicon modified resin according to claim 1, wherein:

the solvent comprises one or more of n-butyl acetate, propylene glycol methyl ether acetate and xylene.

6. The method for preparing a silicon modified resin according to claim 1, wherein:

the catalyst comprises at least one of an organotin catalyst and an organotitanium catalyst.

7. The method for preparing a silicon modified resin according to claim 1, wherein:

in S2, the temperature is controlled to be 130-150 ℃, and the temperature is kept for 2 hours; in S3, the temperature is controlled to be 120-130 ℃.

8. The method for preparing a silicon modified resin according to claim 1, wherein:

the amount of the solvent added in the S2 is 10-20% of the total amount of the solvent; the ratio of the catalyst to the solvent in S3 is 1: 10-1: 20.

9. The method for preparing a silicon modified resin according to claim 1, wherein:

cooling to 50-70 ℃ in S5.

10. A silicon-modified resin characterized by: prepared by the method for preparing the silicon modified resin as described in any one of claims 1 to 9.

Technical Field

The invention belongs to the field of coatings, and particularly relates to a preparation method of silicon modified resin and the silicon modified resin.

Background

Industrial coatings are generally required to have good leveling, distinctness of image and anti-cratering properties, and the films formed by using such industrial coatings are uniform and smooth, and the obtained coatings have good decoration. The resin for the existing industrial coating is generally acrylic resin or polyester resin, the self leveling property and the anti-shrinkage property of the acrylic resin or the polyester resin are relatively poor, and a leveling agent is required to be added to reduce the surface tension of an acrylic resin or polyester resin system, so that the resin system has the leveling property and the anti-shrinkage property under a wet film condition, and good distinctness of image after the coating is cured is realized, and the decorative defect of the appearance of the coating caused by the original shrinkage factor is reduced. However, such resin systems formed by the need for additional levelling agents have the significant disadvantage that: the flatting agent is compatible with acrylic resin or polyester resin only within a certain range due to the characteristics of the material of the flatting agent; if the addition amount of the leveling agent is small, the leveling effect of the coating is poor, and the coating is easy to have the condition of poor leveling of the coating such as orange peel and shrinkage cavity; if the addition amount of the leveling agent is large, the coating defects such as foam stabilization, fogging and the like can occur on the coating; meanwhile, part of the leveling agent is easy to decompose at a certain temperature, and when the curing temperature of the coating is higher, the decomposition product of the leveling agent can reduce the low interfacial tension of the original cured coating, so that the reworking and recoating of the coating are difficult or the adhesion between the coatings after the reworking and recoating is poor.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide a preparation method of silicon modified resin.

The preparation method of the silicon modified resin comprises the following steps:

s1, weighing hydroxyl-containing resin, siloxane oligomer, catalyst and solvent; s2: adding the hydroxyl-containing resin, the siloxane oligomer and part of the solvent into the same reaction vessel, heating and preserving heat; s3: adding the catalyst and part of the solvent, and reacting under heating; s4: and cooling to obtain the silicon modified resin.

According to the preparation method of the silicon modified resin, terminal hydroxyl in the hydroxyl-containing resin and siloxane oligomer containing methoxyl or ethoxyl are subjected to ester exchange reaction under the action of a catalyst to generate the silicon modified resin with polysiloxane contained in a side chain. The silicon modified resin has lower surface tension, the coating made of the silicon modified resin has good self-leveling property and anti-shrinkage property when a film is wet, and the transparency and the refractive index of the silicon modified resin are obviously improved compared with those of common hydroxyl acrylic resin or hydroxyl polyester resin, so that the coating made of the silicon modified resin has excellent distinctness of image and good coating permeability after being cured. The silicon modified resin has repairability in the temperature range of 100-150 ℃, because siloxane has high temperature resistance, the coating can be continuously coated under the high-temperature condition after the coating is cured, and unreacted methoxyl or ethoxyl exists on the side chain of the silicon modified resin, and the side chain can be bonded with the recoated coating so as to enhance the adhesion.

Further, the content of the hydroxyl resin is 60-80%, the content of the siloxane oligomer is 2-5%, the content of the solvent is 15-35%, and the content of the catalyst is 0.1-1%. This is a specific embodiment of the feeding, and if the addition amount of the siloxane oligomer is less than 2%, the leveling effect of the silicon modified resin is not good; if the amount of the siloxane oligomer added is more than 5%, distinctness of image and recoatability of the silicon-modified resin are affected. If the addition amount of the catalyst is less than 0.1%, the ester exchange reaction is incomplete, and the self-leveling property and the distinctness of image of the coating are influenced; if the addition amount of the catalyst is higher than 1.0%, the reaction rate of the ester exchange reaction is too high, the molecular weight distribution is not uniform, and the silicon modified resin generates a surface tension gradient difference, so that shrinkage cavities and orange peels are generated in the leveling process of the coating.

Further, the hydroxyl content of the hydroxyl-containing resin is 3-6%. If the hydroxyl content in the hydroxyl-containing resin is lower than 3 percent, and the hydroxyl-containing resin and the siloxane oligomer are difficult to completely react, the synthesized silicon modified resin does not have good leveling property, distinctness of image and anti-cratering property; if the hydroxyl content in the hydroxyl-containing resin is more than 6%, the siloxane oligomer must be added in an increased amount to achieve good leveling property by grafting the siloxane oligomer onto each hydroxyl-containing resin molecule, which may cause an increase in the cost of preparing the silicon modified resin, and may also cause an excessive shrinkage of a coating obtained by coating the silicon modified resin during re-curing, which may affect the appearance and performance of the coating.

Further, the siloxane oligomer contains 20-50% of methoxyl or ethoxyl and has a molecular weight of 300-1000. If the siloxane oligomer has a methoxy or ethoxy content of less than 25% and a molecular weight of more than 1000, or if the siloxane oligomer has a methoxy or ethoxy content of more than 50% and a molecular weight of less than 300, the silicone-modified resin cannot have good self-leveling properties and distinctness of image.

Further, the solvent comprises one or more of n-butyl acetate, propylene glycol methyl ether acetate and xylene. This is a specific embodiment, and the hydroxyl group-containing resin and the siloxane oligomer are dissolved and reacted.

Further, the catalyst includes at least one of an organotin catalyst and an organotitanium catalyst. The catalyst reacts the hydroxyl-containing resin and siloxane oligomer.

Further, controlling the temperature to be 130-150 ℃ in S2, and preserving the heat for 2 hours; and S3, controlling the temperature to be 120-130 ℃, and heating to enable the hydroxyl-containing resin and the siloxane oligomer to react.

Further, the amount of the solvent added in the S2 is 10-20% of the total amount of the solvent; the ratio of the catalyst to the solvent in S3 is 1: 10-1: 20. A solvent is added in S2 to dissolve the hydroxyl group-containing resin and siloxane oligomer, and the solvent is added in S3 to dissolve the catalyst, so the amount of the solvent added in S3 depends on the amount of the catalyst added.

Further, the temperature is reduced to 50-70 ℃ in S5, so that the reaction of the hydroxyl-containing resin and the siloxane oligomer is terminated.

The invention also provides a silicon modified resin prepared by the preparation method of the silicon modified resin, and the silicon modified resin has leveling property, distinctness of image, anti-shrinkage property and recoatability.

Detailed Description

The invention provides a preparation method of silicon modified resin, which comprises the following steps:

s1: weighing hydroxyl-containing resin, siloxane oligomer, catalyst and solvent;

s2: adding the hydroxyl-containing resin, the siloxane oligomer and part of the solvent into the same reaction vessel, heating and preserving heat;

s3: adding the catalyst and part of the solvent, and reacting under heating;

s4: and cooling to obtain the silicon modified resin.

In S2, the temperature is raised to 130-150 ℃, and the temperature is kept for 2 hours.

The invention provides a preparation method of silicon modified resin, which takes hydroxyl-containing resin as a main chain, and generates ester exchange between terminal hydroxyl and siloxane oligomer containing methoxyl or ethoxyl under the action of a catalyst to generate silicon modified resin with polysiloxane-containing side chains, wherein the reaction is as follows:

wherein R is methyl or ethyl, R' is organic alkane or aromatic hydrocarbon blending main chain containing hydroxyl propylene resin or hydroxyl polyester.

The silicon modified resin has lower surface tension, the coating made of the silicon modified resin has good self-leveling property and anti-shrinkage property when a film is wet, and the transparency and the refractive index of the silicon modified resin are obviously improved compared with those of common hydroxyl acrylic resin or hydroxyl polyester resin, so that the coating made of the silicon modified resin has excellent distinctness of image and good coating permeability after being cured; the silicon modified resin has repairability in the temperature range of 100-150 ℃, because siloxane has high temperature resistance, the coating can be continuously coated under the high-temperature condition after the coating is cured, and unreacted methoxyl or ethoxyl exists on the side chain of the silicon modified resin, and the unreacted methoxyl or ethoxyl can be bonded with the recoated coating so as to enhance the adhesion between the coatings.

The content of the hydroxyl resin is 60-80%, the content of the siloxane oligomer is 2-5%, the content of the solvent is 15-35%, and the content of the catalyst is 0.1-1%.

The hydroxyl content in the hydroxyl-containing resin is 3-6%. The hydroxyl-containing resin comprises one or two of hydroxyl acrylic resin and hydroxyl polyester resin. If the hydroxyl content in the hydroxyl-containing resin is lower than 3 percent, and the hydroxyl-containing resin and the siloxane oligomer are difficult to completely react, the synthesized silicon modified resin does not have good leveling property, distinctness of image and anti-cratering property; if the hydroxyl content in the hydroxyl-containing resin is more than 6%, the siloxane oligomer must be added in an increased amount to achieve good leveling property by grafting the siloxane oligomer onto each hydroxyl-containing resin molecule, which may cause an increase in the cost of preparing the silicon modified resin, and may also cause an excessive shrinkage of a coating obtained by coating the silicon modified resin during re-curing, which may affect the appearance and performance of the coating.

The siloxane oligomer contains 25-50% of methoxyl or ethoxyl and has a molecular weight of 300-1000. The siloxane oligomer has low surface tension, and methoxyl or ethoxyl can perform ester exchange reaction with hydroxyl in hydroxyl-containing resin at a certain temperature to generate silicon modified resin with a siloxane group on a side chain, so that the silicon modified resin has good leveling property. If the addition amount of the siloxane oligomer is less than 2%, the leveling effect of the silicon modified resin is poor; if the amount of the siloxane oligomer added is more than 5%, distinctness of image and recoatability of the silicon-modified resin are affected. If the siloxane oligomer has a methoxy or ethoxy content of less than 25% and a molecular weight of more than 1000, or if the siloxane oligomer has a methoxy or ethoxy content of more than 50% and a molecular weight of less than 300, the silicone-modified resin cannot have good self-leveling properties and distinctness of image.

The solvent comprises one or more of n-butyl acetate, propylene glycol monomethyl ether acetate and xylene, and the purity of the solvent is more than 99%.

The catalyst comprises one of an organic tin catalyst and an organic titanium catalyst, and the purity is more than 98%. The addition amount of the catalyst is 0.1-1%, and if the addition amount of the catalyst is less than 0.1%, the ester exchange reaction is incomplete, and the self-leveling property and the distinctness of image of the coating are affected; if the addition amount of the catalyst is higher than 1.0%, the reaction rate of the ester exchange reaction is too high, the molecular weight distribution is not uniform, and the silicon modified resin generates a surface tension gradient difference, so that shrinkage cavities and orange peels are generated in the leveling process of the coating.

Example 1

S1: weighing 60% of hydroxyl-containing resin, 4.9% of siloxane oligomer, 35% of solvent and 0.1% of catalyst;

s2: heating the hydroxyl-containing resin, the siloxane oligomer and the solvent to 130-150 ℃ within 2 hours at the rotating speed of 500-800 RPM, and preserving the temperature for two hours; wherein the amount of the added solvent is 10% of the total amount of the solvent;

s3: adding the catalyst and the solvent into the material at the rotating speed of 300-500 RPM, wherein the ratio of the catalyst to the solvent is 1:10, and the temperature is maintained at 120-130 ℃; increasing the rotating speed to 1000 RPM-1500 RPM, and reacting for 1 hour;

s4: sampling and analyzing the refractive index and viscosity of the product, adding the residual solvent after the refractive index and viscosity reach the standard, and cooling to 50-70 ℃ to obtain silicon modified resin;

s5: the filtration and packaging are carried out by using a 5 mu m bag filter.

Example 2

S1: weighing 80% of hydroxyl-containing resin, 4% of siloxane oligomer, 15% of solvent and 1% of catalyst;

s2: heating the hydroxyl-containing resin, the siloxane oligomer and the solvent to 130-150 ℃ within 2 hours at the rotating speed of 500-800 RPM, and preserving the temperature for two hours; wherein the amount of the added solvent is 20% of the total amount of the solvent;

s3: adding the catalyst and the solvent into the material at the rotating speed of 300-500 RPM, wherein the ratio of the catalyst to the solvent is 1:20, and the temperature is maintained at 120-130 ℃; increasing the rotating speed to 1000 RPM-1500 RPM, and reacting for 1 hour;

s4: sampling and analyzing the refractive index and viscosity of the product, adding the residual solvent after the refractive index and viscosity reach the standard, and cooling to 50-70 ℃ to obtain silicon modified resin;

s5: the filtration and packaging are carried out by using a 5 mu m bag filter.

Example 3

S1: weighing 80% of hydroxyl-containing resin, 5% of siloxane oligomer, 14% of solvent and 1% of catalyst;

s2: heating the hydroxyl-containing resin, the siloxane oligomer and the solvent to 130-150 ℃ within 2 hours at the rotating speed of 500-800 RPM, and preserving the temperature for two hours; wherein the amount of the added solvent is 20% of the total amount of the solvent;

s3: adding the catalyst and the solvent into the material at the rotating speed of 300-500 RPM, wherein the ratio of the catalyst to the solvent is 1:20, and the temperature is maintained at 120-130 ℃; increasing the rotating speed to 1000 RPM-1500 RPM, and reacting for 1 hour;

s4: sampling and analyzing the refractive index and viscosity of the product, adding the residual solvent after the refractive index and viscosity reach the standard, and cooling to 50-70 ℃ to obtain silicon modified resin;

s5: the filtration and packaging are carried out by using a 5 mu m bag filter.

Example 4

S1: weighing 80% of hydroxyl-containing resin, 2% of siloxane oligomer, 17% of solvent and 1% of catalyst;

s2: heating the hydroxyl-containing resin, the siloxane oligomer and the solvent to 130-150 ℃ within 2 hours at the rotating speed of 500-800 RPM, and preserving the temperature for two hours; wherein the amount of the added solvent is 10% of the total amount of the solvent;

s3: adding the catalyst and the solvent into the material at the rotating speed of 300-500 RPM, wherein the ratio of the catalyst to the solvent is 1:20, and the temperature is maintained at 120-130 ℃; increasing the rotating speed to 1000 RPM-1500 RPM, and reacting for 1 hour;

s4: sampling and analyzing the refractive index and viscosity of the product, adding the residual solvent after the refractive index and viscosity reach the standard, and cooling to 50-70 ℃ to obtain silicon modified resin;

s5: the filtration and packaging are carried out by using a 5 mu m bag filter.

The properties of the resin systems formed by examples 1-4, the commercially available common hydroxyl resin and the commercially available common hydroxyl resin leveling agent were measured on a 30cm × 30cm plate, and the measurement results are shown in table 1-1:

TABLE 1-1

Among them, the adhesion test of recoatability is a test according to the national standard GB/T9286, and for general use, 0 to 3 grades are satisfactory. The adhesion force level 0 represents that the cutting edge is completely smooth, and no one line falls off; adhesion level 1 represents that a little coating falls off at the intersection of the cuts, but the cross cutting area is affected and cannot be obviously more than 5%; adhesion rating 4 represents coating flaking along the cut edge large fragments and/or some squares partially or completely flaking, with the affected cross cut area being significantly greater than 35% but not significantly greater than 65%.

The present invention is not limited to the above-described embodiments, and various modifications and variations of the present invention are intended to be included within the scope of the claims and the equivalent technology of the present invention if they do not depart from the spirit and scope of the present invention.