CN112851949B - Organic silicon resin containing amide structure and preparation method and application thereof - Google Patents

An organic silicon resin containing an amide structure, a preparation method and application thereof, relating to the field of high polymer materials; the method comprises the following steps: s1, mixing 3-aminopropyl tri (ethoxy) silane, tetramethyl silicate and an acylating agent to obtain a mixed solution; the acylating agent is carboxylic acid or anhydride, and when the acylating agent is carboxylic acid, the molar ratio of the 3-aminopropyl tri (ethoxy) silane to the tetramethylsilicate to the carboxyl of the carboxylic acid is 1:0.5-1.5:0.9-1.1; when the acylating agent is acid anhydride, the molar ratio of the 3-aminopropyl tri (ethoxy) silane to the tetramethyl silicate to the acid anhydride is 2:1-3:0.9-1.1; s2, heating the mixed solution for reaction to obtain the organic silicon resin. According to the preparation method, the tetramethyl silicate is added, so that the acylating agent and the aminosilane coupling agent react to directly generate the organic silicon resin containing the amide structure, special equipment and harsh conditions are not needed in the preparation method, the process is simple, large-scale generation is easy to realize, and the preparation method has strong practicability.

Organic silicon resin containing amide structure and preparation method and application thereof

Technical Field

The invention belongs to the field of high polymer materials, and particularly relates to an organic silicon resin containing an amide structure, and a preparation method and application thereof.

Background

Polyamide materials have wide application in many fields due to their excellent properties, however, there are still materials that are susceptible to acid-base catalyzed decomposition; wholly aromatic polyamides are excellent in various properties but high in cost, while aliphatic and semiaromatic polyamides are poor in temperature resistance. It is therefore of interest to develop a process which improves the properties of polyamide articles, such as modification with silicone coupling agents.

The silicone functional resins are generally prepared by cohydrolytic polycondensation of a silane coupling agent with silicone monomers. Classical silane coupling agents, of the general formula YSiX ₃ Wherein X is a group that can be hydrolyzed to eventually form Si-OH, and can also react with Si-OH on other molecules or substrate surfaces to form Si-O-Si bonds. Y is a non-hydrolytic group, and the tail end of the Y is a functional group which is easy to react, such as hydroxyl, sulfhydryl, amino, epoxy hydrocarbon, methacryloxy, isocyanate, alkenyl and the like, and can realize the connection of silane and other organic molecules.

In general, carboxylic acids and organic amines are difficult to react directly to form amides. The synthesis of amides therefore often requires highly active substrates in the form of acid chlorides, anhydrides, etc., or with the aid of various condensing agents and catalysts, such as carbodiimides, onium salts, organophosphonium species, etc., which are of high cost and limit their use in industrial fields.

Disclosure of Invention

In order to overcome the defects of the prior art, one of the purposes of the invention is to provide a preparation method of the organic silicon resin containing an amide structure, which is to prepare the functional organic silicon resin containing the amide structure through modification and optimization by taking an amino silane coupling agent as a raw material. The preparation method does not need special equipment and harsh conditions, has simple process, rich raw materials and low price, is easy to realize large-scale generation, and has strong practicability.

The second object of the present invention is to provide an amide structure-containing silicone resin.

The invention further aims to provide an application of the organic silicon resin containing the amide structure in a polyamide material surface coating. The organic silicon resin is coated on the surface of the polyamide fiber product and dried, so that the mechanical strength and the alkali corrosion resistance of the polyamide fiber product can be improved.

One of the purposes of the invention is realized by adopting the following technical scheme:

a method for preparing an amide structure-containing organic silicon resin, which comprises the following steps:

s1, mixing 3-aminopropyl tri (ethoxy) silane, tetramethyl silicate and an acylating agent to obtain a mixed solution; the acylating agent is carboxylic acid or anhydride, and when the acylating agent is carboxylic acid, the molar ratio of the 3-aminopropyl tri (ethoxy) silane to the carboxyl of the carboxylic acid is 1:0.5-1.5:0.9-1.1; when the acylating agent is acid anhydride, the mole ratio of 3-aminopropyl tri (ethoxy) silane, tetramethyl silicate and anhydride is 2:1-3:0.9-1.1;

s2, heating the mixed solution for reaction to obtain the organic silicon resin.

Further, the preparation method comprises the following specific steps:

s1, mixing 3-aminopropyl tri (ethoxy) silane, tetramethyl silicate and carboxylic acid to obtain a mixed solution; the carboxylic acid is monocarboxylic acid, and the molar ratio of the 3-aminopropyl tri (ethoxy) silane to the tetramethyl silicate to the monocarboxylic acid is 1:0.5-1.5:0.9-1.1;

s2, heating the mixed solution at 80-90 ℃ for reaction for 3-4 hours to obtain the organic silicon resin.

Further, the monocarboxylic acid is acetic acid.

Further, the preparation method comprises the following specific steps:

s1, mixing 3-aminopropyl tri (ethoxy) silane, tetramethyl silicate and carboxylic acid to obtain a mixed solution; the carboxylic acid is dicarboxylic acid, and the molar ratio of the 3-aminopropyl tri (ethoxy) silane, the tetramethyl silicate and the dicarboxylic acid is 2:1-3:0.9-1.1;

s2, heating the mixed solution at 80-90 ℃ for reaction for 3-4 hours to obtain the organic silicon resin.

The reaction equation of the preparation step is shown in the following formula I:

further, the dicarboxylic acid is succinic acid and/or terephthalic acid.

Further, the preparation method comprises the following specific steps:

s1, preparing a mixed solution, which comprises the following specific steps:

1) Mixing 3-aminopropyl tri (ethoxy) silane with anhydride, heating and stirring at 70 ℃ for 30-40min, and obtaining an intermediate product after the solid anhydride is completely dissolved; the molar ratio of the 3-aminopropyl tri (ethoxy) silane to the anhydride is 1:0.9-1.1;

2) Dissolving 3-aminopropyl tri (ethoxy) silane and tetramethyl silicate in 6-8 parts of absolute ethyl alcohol, and adding the mixture into the intermediate product to obtain a mixed solution; the molar ratio of the 3-aminopropyl tri (ethoxy) silane to the tetramethyl silicate is 1:1-3;

s2, heating the mixed solution at 90-100 ℃ to react for 4-6 hours to obtain the organic silicon resin.

The reaction equation of the preparation step is shown as the following formula (II):

further, the mass of 3-aminopropyl tris (ethoxy) silane added in step 2) is the same as the mass of 3-aminopropyl tris (ethoxy) silane added in step 1).

Further, the anhydride is succinic anhydride or maleic anhydride.

The second purpose of the invention is realized by adopting the following technical scheme:

comprises the following components in parts by mole:

1-3 parts of tetramethyl silicate;

2 parts of 3-aminopropyl tri (ethoxy) silane;

1.8-2.2 parts of monocarboxylic acid;

or,

1-3 parts of tetramethyl silicate;

2 parts of 3-aminopropyl tri (ethoxy) silane;

dicarboxylic acid/anhydride 0.9-1.1 parts.

The third purpose of the invention is realized by adopting the following technical scheme:

provides an application of an organic silicon resin containing an amide structure in a polyamide material surface coating.

Compared with the prior art, the invention has the beneficial effects that:

according to the preparation method of the organic silicon resin containing the amide structure, the silicon resin is a cured product of the amide silane coupling agent and the tetramethyl silicate hydrolysate, and the acylating agent and the amino silane coupling agent can directly react to generate the organic silicon resin containing the amide structure by adding the tetramethyl silicate.

The organic silicon resin containing the amide structure is coated on the surface of a polyamide fiber product and dried, so that the mechanical strength and alkali corrosion resistance of the polyamide fiber product can be improved. The organosilicon molecule containing the amide structure has higher polarity, wherein the amide structure can be in hydrogen bond association with other amide molecules to generate tight connection, so that the organosilicon molecule has high affinity and adsorption capacity to the surface of the polyamide material. The organic silicon resin containing the amide structure also contains hydrolysate of tetramethyl silicate, and the hydrolysate can be polycondensed to form a silicon dioxide layer in natural drying or drying, so that the integral mechanical strength of the material can be improved and the corrosion resistance of the base material to alkali can be improved by integrally applying the hydrolysate on the surface of the polyamide material as a coating.

Drawings

Fig. 1 is a line graph of the change in shore hardness after coating according to example 1 of the present invention.

FIG. 2 is a bar graph showing the change in alkali corrosion hardness in example 1 of the present invention.

Detailed Description

The present invention will be further described with reference to the drawings and the detailed description, wherein it should be noted that, on the premise of no conflict, the embodiments described below or the technical features may be arbitrarily combined to form new embodiments.

Example 1

The organic silicon resin containing the amide structure comprises the following components in parts by mass:

4.50g of tetramethyl silicate;

8.04g of 3-aminopropyl tris (ethoxy) silane;

anhydride 1.82g;

the anhydride is succinic anhydride.

The preparation method of the organic silicon resin containing the amide structure comprises the following steps:

s1, preparing a mixed solution, which comprises the following specific steps:

1) Mixing 4.02g of 3-aminopropyl tri (ethoxy) silane and 1.82g of succinic anhydride, heating and stirring for 40min at 70 ℃, and obtaining an intermediate product after the solid anhydride is completely dissolved;

2) 4.02g of 3-aminopropyl tri (ethoxy) silane and 4.50g of tetramethyl silicate are dissolved in 7.00g of absolute ethyl alcohol and added to the intermediate product to obtain a mixed solution;

s2, heating the mixed solution at 100 ℃ for reaction for 4 hours to obtain the organic silicon resin product.

Performance test:

dividing the Kevlar fiber felt block into cuboids of 4.5cm multiplied by 1.4cm multiplied by 1.0cm, and respectively diluting the organic silicon resin compound and TMOS to the concentration of 5% -15% by ethanol. For the experimental felt material with the thickness of 1.0cm, 6mg/cm is respectively selected ² ，12mg/cm ² And 24mg/cm ² The corresponding mass fractions of the three solid content coating amounts are 1.9%,3.8% and 7.5% respectively; the sample is naturally dried in air and then is transferred into an electric blast oven at 120 ℃ to be baked for 30min for solidification.

The cured samples were evaluated for surface hardness using an LX-0A type shore durometer, and each sample was tested for five different locations on the surface, and the results were averaged. The test results are shown in FIG. 1.

Referring to fig. 1, as the coating amount increases, the surface hardness of the kevlar fiber felt increases, and the silicone resin composite improves the hardness of the material more than pure tetramethyl silicate with the same solid content.

Alkali corrosion resistance:

a mixed solvent is prepared by 80% of ethanol and 20% of water (mass ratio), KOH solid is dissolved in the mixed solvent, and KOH solution of 2.5mol/L is prepared and used as alkaline corrosive liquid to test the alkali corrosion resistance of the solidified felt material block.

The sample having the above coating amount of 1.9% was immersed in an alkali solution for 2 hours, and then taken out to be washed with purified water and dried in an oven. The surface hardness was then measured with a Shore durometer and the results are shown in FIG. 2.

Referring to fig. 2, after TMOS coating, the surface hardness of the felt was increased, while the silicone resin composite coated samples had the greatest hardness, with the lowest hardness decay under alkaline solution and the highest hardness after alkaline etching.

Example 2

The organic silicon resin containing the amide structure comprises the following components in parts by mass:

4.28g of tetramethyl silicate;

6.22g of 3-aminopropyl tris (ethoxy) silane;

carboxylic acid 1.68g;

the carboxylic acid is glacial acetic acid.

The preparation method of the organic silicon resin containing the amide structure comprises the following steps:

s1, 6.22g of 3-aminopropyl tri (ethoxy) silane, 4.28g of tetramethyl silicate and 1.68g of glacial acetic acid are mixed and dissolved to obtain a mixed solution;

s2, heating the mixed solution at 90 ℃ for reaction for 3 hours to obtain the organic silicon resin product.

In the embodiment, other solvents are not used, and the reactants are mixed and directly reacted to obtain an amide product; therefore, the embodiment does not add other solvents, and the production process is environment-friendly.

The above embodiments are only preferred embodiments of the present invention, and the scope of the present invention is not limited thereto, but any insubstantial changes and substitutions made by those skilled in the art on the basis of the present invention are intended to be within the scope of the present invention as claimed.