1. A nano calcium carbonate activation system applied to polyurethane adhesive is characterized by comprising the following components: the composite material comprises unactivated nano calcium carbonate slurry, sodium hydroxide, medium-long chain fatty acid, oligomeric thermoplastic resin, sodium stearate, trimethyl methoxy silane, polydimethylsiloxane, a modified dispersing agent and water.

2. The nano calcium carbonate activation system applied to polyurethane glue as claimed in claim 1, wherein the addition amount of the modified dispersant is 1-5 per mill of the dry mass of the nano calcium carbonate slurry.

3. The nano calcium carbonate activation system applied to polyurethane glue as claimed in claim 1, wherein the composition comprises, by weight: 5000 portions of nano calcium carbonate slurry converted calcium carbonate solid, 2 to 9 portions of sodium hydroxide, 20 to 60 portions of medium-long chain fatty acid, 40 to 80 portions of oligomeric thermoplastic resin, 4 to 8 portions of sodium stearate, 3 to 9 portions of trimethyl methoxy silane, 2 to 6 portions of polydimethylsiloxane, 2 to 5 portions of modified dispersant and 1000 portions of water and 2000 portions.

4. The nano calcium carbonate activation system for polyurethane glue of claim 1, wherein the medium-long chain fatty acid is one or a mixture of more than two of lauric acid, palmitic acid, stearic acid and dimerized fatty acid.

5. The nano calcium carbonate activation system for polyurethane glue as claimed in claim 1, wherein the oligomeric thermoplastic resin is one or a mixture of two or more of aliphatic resin (C5), cycloaliphatic resin (DCPD), aromatic resin (C9), aliphatic/aromatic copolymer resin (C5/C9) and hydrogenated petroleum resin with molecular weight of 300-3000.

6. The nano calcium carbonate activation system applied to polyurethane glue of claim 1, wherein the modified dispersant comprises the following components in parts by weight: 15-25 parts of diisobutylene, 10-20 parts of maleic anhydride, 5-15 parts of sodium sulfamate, 4-8 parts of sodium persulfate, 2-5 parts of sodium hydroxide, 9-19 parts of sodium methallyl sulfonate, 10-20 parts of maleic anhydride, 4-9 parts of sodium bisulfite, 15-35 parts of deionized water, 14-28 parts of acrylic monomer, 4-9 parts of ammonium persulfate and KH-5603-9 parts of silane coupling agent.

7. The nano calcium carbonate activation system for polyurethane glue of claim 5, wherein the preparation method of the modified dispersant comprises the following steps:

I. uniformly mixing diisobutylene, maleic anhydride, sodium sulfamate and sodium persulfate, heating to 200-300 ℃, preserving heat for 20-40min, stirring at the rotating speed of 650r/min for 1-2h, then adding sodium hydroxide and uniformly mixing to obtain a material a;

II. Uniformly mixing sodium methallyl sulfonate, maleic anhydride, sodium bisulfite and deionized water, stirring for 20-30 min in a constant-temperature water bath at the rotating speed of 350-650 r/min, then heating to 80-90 ℃, preserving heat for 1-2h, then adding an acrylic monomer and ammonium persulfate, uniformly mixing, stirring for 10-20 min at the rotating speed of 850-1050 r/min, and neutralizing until the pH value is 8 to obtain a material b;

and III, uniformly mixing the material a and the material b, heating to 80-120 ℃, preserving heat for 20-40min, adding a silane coupling agent KH-560, uniformly mixing, preserving heat for 10-20 min at the temperature of 110-.

8. The method for activating nano calcium carbonate applied to polyurethane glue according to any one of claims 1 to 7, characterized by comprising the following steps:

s1, putting the carbonized untreated nano calcium carbonate slurry into an activation barrel, adding sodium hydroxide into the nano calcium carbonate slurry, uniformly stirring, heating to 80-100 ℃, and stirring for 3-8 hours to obtain a material A;

s2, gradually adding sodium stearate, medium-long chain fatty acid and oligomeric thermoplastic resin

Uniformly stirring in hot water at the temperature of 80-100 ℃ to obtain a material B;

s3, uniformly mixing the material A, the material B, trimethyl methoxysilane, polydimethylsiloxane and a modified dispersing agent, and stirring at the rotating speed of 850-1050 r/min for 20-50 min to obtain a material C;

and S4, performing filter pressing, drying and depolymerization on the material C to obtain the active nano calcium carbonate.

Background

The polyurethane adhesive is one of three main adhesive products which are in parallel with silicone adhesive and polysulfide adhesive at present in China, and the polyurethane adhesive contains aminomethyl ester groups (NHCOO) on the main chain^-) Because the structure contains polar groups, the adhesive property to various materials is improved, and the adhesive has high activity and can be cured at normal temperature; the adhesive film is tough, impact resistant, high in peel strength, and has excellent ultralow temperature resistance, oil resistance and wear resistanceIt is widely used for bonding metal, wood, plastic, glass, etc. The doping amount of the nano calcium carbonate in the production of the polyurethane adhesive can reach 40-50%, and the nano calcium carbonate is used as the cheapest component in the formula of the polyurethane adhesive, and has a vital role in increasing the volume, reducing the cost and modifying the polyurethane adhesive, and in addition, the physical and chemical properties of the nano calcium carbonate also greatly influence the quality of the polyurethane adhesive.

The raw materials of the polyurethane adhesive formula system are generally dehydrated, because the polyurethane adhesive system contains a highly active-N-C-O group, and the water introduced into the system by the raw materials reacts with the-N-C-0 group to generate an amine compound, which can cause the formation of a cross-linking bond and influence the storage stability; meanwhile, the added raw materials are required to be basically not alkaline, because the alkalinity brought by the raw materials can promote the formation of allophanate crosslinking bonds and biuret crosslinking bonds, increase the viscosity of polyurethane glue products, shorten the storage period of the polyurethane glue, and can cause the premature gluing of a polyurethane glue system, so that the moisture content of the nano calcium carbonate suitable for the requirement of the polyurethane glue system is required to be below 0.1%, the pH value is required to be below 8.0, and the nano calcium carbonate is basically not alkaline. The moisture index of the nano calcium carbonate produced at home at present is 0.4 percent or higher, the pH value is generally between 9.5 and 10.5, and in order to overcome the defects, the nano calcium carbonate needs to be subjected to thorough surface activation modification treatment.

The kind and composition of the surface treating agent undoubtedly play a decisive role in the final modification effect. The following classes of surface treatment agents are commonly used: fatty acid, grease, wax, nonionic surfactant, silicone, titanate, amine, phosphate, aluminum compound, and zirconium-aluminum compound. The most commonly used are stearic acid and salts thereof, paraffin, DOP, coconut oil and other long-chain fatty acids, but the mechanical strength of the filled polymer is poor due to weak bonding force among fatty acid chains; the surface modifier with ideal activating and modifying effects is various coupling agents such as silane, titanate, aluminate and the like, but has respective defects, for example, the single silane coupling agent has no obvious modifying effect on the nano calcium carbonate, the titanate coupling agent has dark color, the aluminate coupling agent is easy to hydrolyze and can not be exposed in the air, and the wet modification of the nano calcium carbonate is limited by the problems.

The chinese invention patent CN102702795A discloses a preparation method of nano calcium carbonate special for polyurethane glue. The method adopts fatty acid, organic acid ester and silane coupling agent to carry out surface coating modification on the nano calcium carbonate. The silane coupling agent with extremely weak moisture absorption is used for carrying out surface hydrophobic treatment on the nano calcium carbonate particles, so that the moisture of a product is reduced to be below 0.1%, the silane coupling agent is physically adsorbed on the surface of the calcium carbonate, and the partial treating agent is easily subjected to damp hydrolysis in the air to cause inactivation. In addition, these treating agents have poor compatibility with the segments of the polyurethane system, are difficult to fill in large amounts, and have poor product stability.

The Chinese invention patent CN109504130A discloses a preparation method of nano calcium carbonate for silane-terminated polyurethane sealant, which adds a surface treating agent compounded by trimethylsilanol, dimethylformamide and fatty acid salt to carry out surface modification on the nano calcium carbonate. However, the method introduces trimethylsilanol in the process of surface modification of the nano calcium carbonate, and the obtained nano calcium carbonate is also not beneficial to the storage stability of the sealant system.

Therefore, in order to solve the above problems, it is necessary to develop an activation system and an activation method for preparing active nano calcium carbonate to improve the storage stability and mechanical properties of the polyurethane adhesive system.

Disclosure of Invention

Aiming at the problems of the existing nano calcium carbonate, the invention provides an activation system and an activation method for preparing active nano calcium carbonate, the active nano calcium carbonate has better compatibility with a polyurethane adhesive system, and the storage stability and the mechanical property of the polyurethane adhesive can be obviously improved.

In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:

in a first aspect, the present invention provides an activation system of nano calcium carbonate for polyurethane adhesive, which comprises: the composite material comprises unactivated nano calcium carbonate slurry, sodium hydroxide, medium-long chain fatty acid, oligomeric thermoplastic resin, sodium stearate, trimethyl methoxy silane, polydimethylsiloxane, a modified dispersing agent and water.

Further, the invention provides a nano calcium carbonate activation system applied to polyurethane glue, wherein the addition amount of trimethyl methoxy silane and polydimethylsiloxane is 1-10% of the dry basis mass of nano calcium carbonate slurry, and the addition amount of the modified dispersing agent is 1-5% of the dry basis mass of the nano calcium carbonate slurry.

As a preferred technical scheme of the invention, the activating system comprises the following components in parts by weight: 5000 portions of nano calcium carbonate slurry converted calcium carbonate solid, 2 to 9 portions of sodium hydroxide, 20 to 60 portions of medium-long chain fatty acid, 40 to 80 portions of oligomeric thermoplastic resin, 4 to 8 portions of sodium stearate, 3 to 9 portions of trimethyl methoxy silane, 2 to 6 portions of polydimethylsiloxane, 2 to 5 portions of modified dispersant and 1000 portions of water and 2000 portions.

In the activation system, the medium-long chain fatty acid is one or a mixture of more than two of lauric acid, palmitic acid, stearic acid and dimerized fatty acid.

In the activation system, the oligomeric thermoplastic resin is one or a mixture of more than two of aliphatic resin (C5), alicyclic resin (DCPD), aromatic resin (C9), aliphatic/aromatic copolymer resin (C5/C9) and hydrogenated petroleum resin with the molecular weight of 300-3000.

In the activation system, the modified dispersant comprises the following components in parts by weight: 15-25 parts of diisobutylene, 10-20 parts of maleic anhydride, 5-15 parts of sodium sulfamate, 4-8 parts of sodium persulfate, 2-5 parts of sodium hydroxide, 9-19 parts of sodium methallyl sulfonate, 10-20 parts of maleic anhydride, 4-9 parts of sodium bisulfite, 15-35 parts of deionized water, 14-28 parts of acrylic monomer, 4-9 parts of ammonium persulfate and KH-5603-9 parts of silane coupling agent.

The preparation method of the modified dispersant comprises the following steps:

I. uniformly mixing diisobutylene, maleic anhydride, sodium sulfamate and sodium persulfate, heating to 200-300 ℃, preserving heat for 20-40min, stirring at the rotating speed of 650r/min for 1-2h, then adding sodium hydroxide and uniformly mixing to obtain a material a;

II. Uniformly mixing sodium methallyl sulfonate, maleic anhydride, sodium bisulfite and deionized water, stirring for 20-30 min in a constant-temperature water bath at the rotating speed of 350-650 r/min, then heating to 80-90 ℃, preserving heat for 1-2h, then adding an acrylic monomer and ammonium persulfate, uniformly mixing, stirring for 10-20 min at the rotating speed of 850-1050 r/min, and neutralizing until the pH value is 8 to obtain a material b;

and III, uniformly mixing the material a and the material b, heating to 80-120 ℃, preserving heat for 20-40min, adding a silane coupling agent KH-560, uniformly mixing, preserving heat for 10-20 min at the temperature of 110-.

In a second aspect, the present invention also provides a method for activating nano calcium carbonate applied to polyurethane glue by using the reactive system of the first aspect, comprising the following steps:

s1, putting the carbonized untreated nano calcium carbonate slurry into an activation barrel, adding sodium hydroxide into the nano calcium carbonate slurry, uniformly stirring, heating to 80-100 ℃, and stirring for 3-8 hours to obtain a material A;

s2, gradually adding sodium stearate, medium-long chain fatty acid and oligomeric thermoplastic resin

Uniformly stirring in hot water at the temperature of 80-100 ℃ to obtain a material B;

s3, uniformly mixing the material A, the material B, trimethyl methoxysilane, polydimethylsiloxane and a modified dispersing agent, and stirring at the rotating speed of 850-1050 r/min for 20-50 min to obtain a material C;

and S4, performing filter pressing, drying and depolymerization on the material C to obtain the active nano calcium carbonate.

In the nano calcium carbonate activation system, the combination of medium-long chain fatty acid, oligomeric thermoplastic resin and sodium stearate can increase the affinity of nano calcium carbonate and an organic phase, improve the dispersibility of the nano calcium carbonate in polyurethane glue and further improve the storage stability of the polyurethane glue; when trimethyl methoxy silane, polydimethylsiloxane and an improved dispersing agent are added into the activation system, the bonding property of the nano calcium carbonate and a high molecular polymer can be improved, and the polymer is filled to ensure that the nano calcium carbonate has good mechanical property.

The components in the activation system are uniformly distributed, and have a synergistic effect with each other, so that excellent effects which cannot be achieved by each single component can be obtained, the pH value of the nano calcium carbonate obtained by the activation system is 7-8, the moisture content is less than or equal to 0.1%, the specific surface area is large, the particle size is small, and the nano calcium carbonate is not easy to agglomerate. The nano calcium carbonate product prepared by the system treatment of the invention has good compatibility with a polyurethane adhesive system, is easy to disperse, enhances the macroscopic combination of the filler and a polyurethane matrix, obviously improves the mechanical property, has good storage stability, strength and tensile property, and can effectively shorten the surface drying time of the polyurethane adhesive.

Detailed Description

For the purpose of facilitating an understanding of the present invention, the present invention will now be described by way of examples. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.

Example 1

The nano calcium carbonate activation system comprises: 2000 parts of nano calcium carbonate slurry converted calcium carbonate solid, 2 parts of sodium hydroxide, 20 parts of medium-long chain fatty acid, 40 parts of oligomeric thermoplastic resin, 4 parts of sodium stearate, 3 parts of trimethyl methoxy silane, 2 parts of polydimethylsiloxane, 2 parts of modified dispersant and 1000 parts of water.

The preparation method of the active nano calcium carbonate comprises the following steps:

s1, putting the carbonized untreated nano calcium carbonate slurry into an activation barrel, adding sodium hydroxide into the nano calcium carbonate slurry, uniformly stirring, heating to 80-100 ℃, and stirring for 3-8 hours to obtain a material A;

s2, gradually adding sodium stearate, medium-long chain fatty acid and oligomeric thermoplastic resin into hot water at the temperature of 80-100 ℃, and uniformly stirring to obtain a material B;

s3, uniformly mixing the material A, the material B, trimethyl methoxysilane, polydimethylsiloxane and a modified dispersing agent, and stirring at the rotating speed of 850-1050 r/min for 20-50 min to obtain a material C;

and S4, performing filter pressing, drying and depolymerization on the material C to obtain the active nano calcium carbonate.

The preparation method of the modified dispersant comprises the following steps:

I. uniformly mixing diisobutylene, maleic anhydride, sodium sulfamate and sodium persulfate, heating to 200-300 ℃, preserving heat for 20-40min, stirring at the rotating speed of 650r/min for 1-2h, then adding sodium hydroxide and uniformly mixing to obtain a material a;

II. Uniformly mixing sodium methallyl sulfonate, maleic anhydride, sodium bisulfite and deionized water, stirring for 20-30 min in a constant-temperature water bath at the rotating speed of 350-650 r/min, then heating to 80-90 ℃, preserving heat for 1-2h, then adding an acrylic monomer and ammonium persulfate, uniformly mixing, stirring for 10-20 min at the rotating speed of 850-1050 r/min, and neutralizing until the pH value is 8 to obtain a material b;

and III, uniformly mixing the material a and the material b, heating to 80-120 ℃, preserving heat for 20-40min, adding a silane coupling agent KH-560, uniformly mixing, preserving heat for 10-20 min at the temperature of 110-.

Example 2

The nano calcium carbonate activation system comprises: 5000 parts of nano calcium carbonate slurry converted calcium carbonate solid, 9 parts of sodium hydroxide, 40 parts of medium-long chain fatty acid, 80 parts of oligomeric thermoplastic resin, 8 parts of sodium stearate, 9 parts of trimethyl methoxy silane, 6 parts of polydimethylsiloxane, 5 parts of modified dispersant and 2000 parts of water.

The preparation method is the same as example 1.

Example 3

The nano calcium carbonate activation system comprises: 3000 parts of nano calcium carbonate slurry converted calcium carbonate solid, 5 parts of sodium hydroxide, 40 parts of medium-long chain fatty acid, 75 parts of oligomeric thermoplastic resin, 6 parts of sodium stearate, 8 parts of trimethyl methoxy silane, 4 parts of polydimethylsiloxane, 6 parts of modified dispersant and 1000 parts of water.

The preparation method is the same as example 1.

Comparative experiment

1. The method for preparing the nano calcium carbonate according to the embodiment 1-3 of the invention

2. Preparation of control group nano calcium carbonate

Control group 1: the procedure of example 1 was repeated, except that trimethylmethoxysilane and polydimethylsiloxane were not added.

Control group 2: the procedure of example 1 was repeated, except that no modified dispersant was added.

Control group 3: the procedure of example 1 was repeated, except that trimethylmethoxysilane, polydimethylsiloxane and modified dispersant were not added.

3. Performance testing of Nano calcium carbonate

TABLE 1 test results of various properties of nano calcium carbonate

Item	Example 1	Example 2	Example 3	Control group 1	Control group 2	Control group 3
							BET specific surface area (m)2/g)	27.8	26.6	24.2	20.4	21.8	19.7
Moisture (%)	≤0.1％	≤0.1％	≤0.1％	0.5％	0.7％	0.7％
							pH	7.4	7.6	7.2	8.4	8.6	8.5

4. Preparation of polyurethane glue

The formula of the polyurethane sealant comprises the following components: 50 parts of polypropylene oxide glycol, 50 parts of polypropylene oxide triol, 25 parts of toluene isocyanate, 30 parts of dioctyl phthalate, 1 part of stannous octoate, 50 parts of nano calcium carbonate and 2 parts of chain extender. The above examples were filled with polyurethane glue according to the above formulation.

Control group 4: the nano calcium carbonate obtained in the comparison group 1 is used as a raw material, and trimethyl methoxy silane and polydimethylsiloxane are added in the preparation process of the polyurethane adhesive. Filling was carried out as above formulation.

Before preparing the sealant, the nano calcium carbonate filler is dried; when the sealant is prepared, firstly, polypropylene oxide glycol, polypropylene oxide triol, toluene isocyanate and dioctyl phthalate are mixed and reacted to obtain a polyurethane prepolymer. And sequentially mixing and stirring the polyurethane prepolymer, the nano calcium carbonate filler and the other auxiliaries, mixing and dispersing, discharging to obtain the polyurethane adhesive, and storing for later use.

5. Mechanical property test of polyurethane adhesive

After filling polyurethane glue with the nano calcium carbonate prepared in the embodiments 1-3 and the control groups 1-4 respectively, testing was performed, firstly, the sealant was made into a 1.8-2.2mm film, and cured for 7 days under standard curing conditions.

The mechanical property test results are shown in table 2:

TABLE 2 test results of various mechanical properties of polyurethane glue

Item	Example 1	Example 2	Example 3	Control group 1	Control group 2	Control group 3	Control group 4
								Tensile strength/MPa	2.34	2.65	2.93	2.02	2.11	2.03	2.09
Elongation at break%	679	623	610	575	580	572	568
								Tear Strength/N/mm	8.4	10.1	12.9	7.9	8.0	7.9	7.8
Surface drying time/h	2.7	2.4	2.6	3.5	3.6	3.3	3.8

As can be seen from Table 2: the polyurethane adhesives prepared from the nano calcium carbonate of examples 1 to 3 are more excellent in mechanical properties than the polyurethane adhesives prepared from the nano calcium carbonate of comparative examples 1 to 4.

6. Stability testing of polyurethane glues

The nano calcium carbonate prepared in examples 1 to 3 and the control groups 1 to 4 of the present invention was filled with polyurethane glue, and then tested. The stability performance test results are shown in table 3:

table 3 shows the results of the stability tests of the polyurethane:

as can be seen from Table 3: the polyurethane adhesives prepared from the nano calcium carbonates of examples 1 to 3 are more excellent in storage stability than the polyurethane adhesives prepared from the nano calcium carbonates of comparative examples 1 to 4.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.