Preparation method of nano calcium carbonate for water-resistant polyurethane adhesive

Abstract

The invention relates to the technical field of a preparation method of nano calcium carbonate for a water-resistant polyurethane adhesive, and discloses a preparation method of nano calcium carbonate for a water-resistant polyurethane adhesive. The coating is prepared from the following components in parts by weight: 25 to 30 parts of nano calcium carbonate powder, 1.1 to 2.5 parts of ultraviolet stabilizer, 2 to 4 parts of nano cellulose, 3 to 5 parts of epoxidized soybean oil, 1.5 to 2.5 parts of dewatering agent, 1.3 to 1.7 parts of plasticizer, 1.2 to 2.4 parts of coupling agent and 0.2 to 0.8 part of lanthanum ricinoleate. According to the invention, polysiloxane-based acrylate is used as a surface modifier, and the contained siloxane group is a hydrophobic group, so that the surface energy of the nano calcium carbonate can be reduced, the compatibility of the nano calcium carbonate and the sealant can be enhanced, and the polyurethane sealant can be endowed with good heat resistance, water resistance and ultraviolet resistance after being modified by the reagent; the nano calcium carbonate powder, the ultraviolet light stabilizer, the water removal agent, the plasticizer, the coupling agent and other auxiliary materials are added, and it is found through tests that the weather resistance is good.

Description

Technical Field

[0001] The invention relates to the technical field of preparation methods of nano calcium carbonate for water-resistant polyurethane adhesive, in particular to a preparation method of nano calcium carbonate for water-resistant polyurethane adhesive. Background Art

[0002] Nano calcium carbonate is an extremely important new type of functional nano-scale filler with excellent performance in industrial calcium carbonate. It can not only fill and increase volume and reduce costs, but also improve the surface color of filled products and improve the comprehensive mechanical properties of products. It is widely used in plastics, rubber, coatings, adhesives, inks and other fields. In the polyurethane sealant processing industry, nano calcium carbonate has become an indispensable and important filler, which mainly plays a reinforcing role and gives the sealant excellent thixotropy. Polyurethane sealants have excellent performance, but because they contain highly polar urethane groups in their main chains, they are sensitive to humidity, which limits the application field of polyurethane adhesives. Most of the existing polyurethane adhesives have poor weather resistance and water resistance, low bonding strength, and are not easy to meet the high requirements for sealing materials in automobile windshields and coastal high temperature and high humidity environments in summer.

[0003] Chinese patent CN105524489A discloses an in-situ emulsification modification method for nano calcium carbonate for polyurethane sealant. The method uses an in-situ emulsification modification method to prepare nano calcium carbonate with good performance suitable for polyurethane glue filling. However, the nano calcium carbonate prepared by this method has little effect on improving the water resistance of polyurethane glue.

[0004] The nano calcium carbonate currently produced cannot meet the demand for filling high-quality polyurethane sealants. The present invention mainly enhances the water resistance of polyurethane sealants by modifying calcium carbonate, reduces the negative impact of the hydrophilicity of calcium carbonate itself on polyurethane sealants, and can effectively improve the mechanical properties of polyurethane sealants. It has strong pertinence and innovation, and has high market application value.

[0005] This case is proposed to solve or improve the shortcomings or deficiencies of the prior art. Summary of the invention

[0006] The present invention solves the technical problem by adopting the following technical solutions:

[0007] 1. A method for preparing nano calcium carbonate for water-resistant polyurethane adhesive, characterized in that it comprises the following steps:

[0008] (1) introducing steam into a nano calcium carbonate suspension having a pH of 7 to 7.1, a specific surface area of ​​22.0 to 28.0 m2 / g, and a mass concentration of 15 to 25%, heating the suspension to 80 to 91° C., adding a polysiloxane acrylate saponified liquid having a dry weight of 2.6 to 3.0% by weight of calcium carbonate, and stirring the saponified liquid for 20 to 30 minutes for a first surface modification to obtain a modified nano calcium carbonate slurry;

[0009] (2) subjecting the modified nano-calcium carbonate slurry obtained in step (1) to vacuum dehydration and drying treatment, controlling the moisture content of the powder to ≤ 0.2%, crushing, and passing through a 250-mesh sieve to obtain a primary nano-calcium carbonate product;

[0010] (3) adding the primary product of nano calcium carbonate into a mixer, heating and stirring, when the material temperature rises to 80-90° C., adding dimethyl silicone oil and Si747 silane coupling agent composite modifier, continuing stirring for a second surface modification, when the material temperature rises to 120-130° C., stopping stirring, discharging, and obtaining modified nano calcium carbonate;

[0011] Add auxiliary materials, which are calculated by weight as follows: 25-30 parts of nano calcium carbonate powder, 1.1-2.5 parts of ultraviolet light stabilizer, 2-4 parts of nano cellulose, 3-5 parts of epoxy soybean oil, 1.5-2.5 parts of dehydrating agent, 1.3-1.7 parts of plasticizer, 1.2-2.4 parts of coupling agent and 0.2-0.8 parts of lanthanum ricinoleate.

[0012] (4) adding auxiliary materials, wherein the auxiliary materials are calculated by weight, and include 20-30 parts of nano calcium carbonate powder, 1.1-2.5 parts of ultraviolet light stabilizer, 2-4 parts of nano cellulose, 3-5 parts of epoxy soybean oil, 1.5-2.5 parts of dehydrating agent, 1.3-1.7 parts of plasticizer, 1.2-2.4 parts of coupling agent, and 0.3-0.8 parts of lanthanum ricinoleate;

[0013] (5) crushing the modified nano calcium carbonate, passing it through a 300 mesh sieve, and packaging it to obtain nano calcium carbonate for water-resistant polyurethane adhesive; the preparation method of the polysiloxane acrylate saponification liquid is as follows: mixing polysiloxane acrylate with a saponifier for reaction, controlling the saponification temperature to be 80-90° C., the saponification time to be 20-30 min, the amount of the saponifier to be 10-17% of the weight of the polysiloxane methacrylate, and the concentration of the saponification liquid to be 4-9%.

[0014] Furthermore, the polysiloxane acrylate saponification liquid includes a saponification liquid of polysiloxane methacrylate and / or polydisiloxane methacrylate.

[0015] Furthermore, the saponifying agent is sodium hydroxide or potassium hydroxide.

[0016] Furthermore, the amount of the composite modifier added in step (3) is 0.7-1.0% by weight of the dry basis of calcium carbonate.

[0017] Furthermore, the mass ratio of dimethyl silicone oil to Si747 silane coupling agent in the composite modifier is 0.125-0.25:1.

[0018] Furthermore, the vacuum degree of the vacuum dehydration is 0.07-0.08 MPa.

[0019] Furthermore, the stirring rate in step (1) and step (3) is 1300-1500 r / min.

[0020] The advantages and positive effects of the present invention are as follows: the present invention uses polysiloxane acrylate as a surface modifier, the siloxane group contained in the present invention is a hydrophobic group, which can reduce the surface energy of nano calcium carbonate and enhance the compatibility of nano calcium carbonate with the sealant. After being modified by the reagent, the polyurethane sealant can be endowed with good heat resistance, water resistance and UV resistance; the present invention is prepared by adding auxiliary materials such as nano calcium carbonate powder, UV stabilizer, dehydrating agent, plasticizer, coupling agent, etc., and is found to have good weather resistance through testing. DETAILED DESCRIPTION

[0021] The embodiments of the present invention are further described in detail:

[0022] 1. A method for preparing nano calcium carbonate for water-resistant polyurethane adhesive, characterized in that it comprises the following steps:

[0023] (1) introducing steam into a nano calcium carbonate suspension having a pH of 7 to 7.1, a specific surface area of ​​22.0 to 28.0 m2 / g, and a mass concentration of 15 to 25%, heating the suspension to 80 to 91° C., adding a polysiloxane acrylate saponified liquid having a dry weight of 2.6 to 3.0% by weight of calcium carbonate, and stirring the saponified liquid for 20 to 30 minutes for a first surface modification to obtain a modified nano calcium carbonate slurry;

[0024] (2) subjecting the modified nano-calcium carbonate slurry obtained in step (1) to vacuum dehydration and drying treatment, controlling the moisture content of the powder to ≤ 0.2%, crushing, and passing through a 250-mesh sieve to obtain a primary nano-calcium carbonate product;

[0025] (3) adding the primary product of nano calcium carbonate into a mixer, heating and stirring, when the material temperature rises to 80-90° C., adding dimethyl silicone oil and Si747 silane coupling agent composite modifier, continuing stirring for a second surface modification, when the material temperature rises to 120-130° C., stopping stirring, discharging, and obtaining modified nano calcium carbonate;

[0026] Add auxiliary materials, which are calculated by weight as follows: 25-30 parts of nano calcium carbonate powder, 1.1-2.5 parts of ultraviolet light stabilizer, 2-4 parts of nano cellulose, 3-5 parts of epoxy soybean oil, 1.5-2.5 parts of dehydrating agent, 1.3-1.7 parts of plasticizer, 1.2-2.4 parts of coupling agent and 0.2-0.8 parts of lanthanum ricinoleate.

[0027] (4) adding auxiliary materials, wherein the auxiliary materials are calculated by weight, and include 20-30 parts of nano calcium carbonate powder, 1.1-2.5 parts of ultraviolet light stabilizer, 2-4 parts of nano cellulose, 3-5 parts of epoxy soybean oil, 1.5-2.5 parts of dehydrating agent, 1.3-1.7 parts of plasticizer, 1.2-2.4 parts of coupling agent, and 0.3-0.8 parts of lanthanum ricinoleate;

[0028] (5) crushing the modified nano calcium carbonate, passing it through a 300 mesh sieve, and packaging it to obtain nano calcium carbonate for water-resistant polyurethane adhesive; the preparation method of the polysiloxane acrylate saponification liquid is as follows: mixing polysiloxane acrylate with a saponifier for reaction, controlling the saponification temperature to be 80-90° C., the saponification time to be 20-30 min, the amount of the saponifier to be 10-17% of the weight of the polysiloxane methacrylate, and the concentration of the saponification liquid to be 4-9%.

[0029] Preferably, the polysiloxane acrylate saponification liquid includes a saponification liquid of polysiloxane methacrylate and / or polydisiloxane methacrylate.

[0030] Preferably, the saponifying agent is sodium hydroxide or potassium hydroxide.

[0031] Preferably, the amount of the composite modifier added in step (3) is 0.7-1.0% by weight of the dry weight of calcium carbonate.

[0032] Preferably, the mass ratio of dimethyl silicone oil to Si747 silane coupling agent in the composite modifier is 0.125-0.25:1.

[0033] Preferably, the vacuum degree of the vacuum dehydration is 0.07-0.08 MPa.

[0034] Preferably, the stirring rate in step (1) and step (3) is 1300-1500 r / min.

[0035] It should be emphasized that the embodiments described in the present invention are illustrative rather than restrictive, and therefore the present invention is not limited to the embodiments described in the specific implementation manners. Any other implementation manners derived by those skilled in the art based on the technical solutions of the present invention also fall within the scope of protection of the present invention.

Claims

1. A method for preparing nano calcium carbonate for water-resistant polyurethane adhesive, characterized in that: The following steps are involved: (1) introducing steam into a nano calcium carbonate suspension having a pH of 7 to 7.1, a specific surface area of ​​22.0 to 28.0 m2 / g, and a mass concentration of 15 to 25%, heating the suspension to 80 to 91° C., adding a polysiloxane acrylate saponified liquid having a dry weight of 2.6 to 3.0% by weight of calcium carbonate, and stirring the saponified liquid for 20 to 30 minutes for a first surface modification to obtain a modified nano calcium carbonate slurry; (2) subjecting the modified nano-calcium carbonate slurry obtained in step (1) to vacuum dehydration and drying treatment, controlling the moisture content of the powder to ≤ 0.2%, crushing, and passing through a 250-mesh sieve to obtain a primary nano-calcium carbonate product; (3) adding the primary product of nano calcium carbonate into a mixer, heating and stirring, when the material temperature rises to 80-90° C., adding dimethyl silicone oil and Si747 silane coupling agent composite modifier, continuing stirring for a second surface modification, when the material temperature rises to 120-130° C., stopping stirring, discharging, and obtaining modified nano calcium carbonate; Add auxiliary materials, which are calculated by weight as follows: 25-30 parts of nano calcium carbonate powder, 1.1-2.5 parts of ultraviolet light stabilizer, 2-4 parts of nano cellulose, 3-5 parts of epoxy soybean oil, 1.5-2.5 parts of dehydrating agent, 1.3-1.7 parts of plasticizer, 1.2-2.4 parts of coupling agent and 0.2-0.8 parts of lanthanum ricinoleate. (4) adding auxiliary materials, wherein the auxiliary materials are calculated by weight, and include 20-30 parts of nano calcium carbonate powder, 1.1-2.5 parts of ultraviolet light stabilizer, 2-4 parts of nano cellulose, 3-5 parts of epoxy soybean oil, 1.5-2.5 parts of dehydrating agent, 1.3-1.7 parts of plasticizer, 1.2-2.4 parts of coupling agent, and 0.3-0.8 parts of lanthanum ricinoleate; (5) crushing the modified nano calcium carbonate, passing it through a 300 mesh sieve, and packaging it to obtain nano calcium carbonate for water-resistant polyurethane adhesive; the preparation method of the polysiloxane acrylate saponification liquid is as follows: mixing polysiloxane acrylate with a saponifier for reaction, controlling the saponification temperature to be 80-90° C., the saponification time to be 20-30 min, the amount of the saponifier to be 10-17% of the weight of the polysiloxane methacrylate, and the concentration of the saponification liquid to be 4-9%.

2. The method for preparing nano calcium carbonate for water-resistant polyurethane adhesive according to claim 1, characterized in that: The polysiloxane acrylate saponification liquid includes a polysiloxane methacrylate and / or a polydisiloxane methacrylate saponification liquid.

3. The method for preparing nano calcium carbonate for water-resistant polyurethane adhesive according to claim 1, characterized in that: The saponifying agent is sodium hydroxide or potassium hydroxide.

4. The method for preparing nano calcium carbonate for water-resistant polyurethane adhesive according to claim 1, characterized in that: The amount of the composite modifier added in step (3) is 0.7-1.0% based on the dry weight of calcium carbonate.

5. The method for preparing nano calcium carbonate for water-resistant polyurethane adhesive according to claim 4, characterized in that: The mass ratio of dimethyl silicone oil to Si747 silane coupling agent in the composite modifier is 0.125-0.25:

1.

6. The method for preparing nano calcium carbonate for water-resistant polyurethane adhesive according to claim 1, characterized in that: The vacuum degree of the vacuum dehydration is 0.07-0.08 MPa.

7. The method for preparing nano calcium carbonate for water-resistant polyurethane adhesive according to claim 1, characterized in that: The stirring rate in step (1) and step (3) is 1300-1500 r / min.