Modification method of special nano calcium carbonate for PVC injection molding material

Abstract

The invention relates to the related technical field of transformer heat dissipation, and discloses a modification method of special nano calcium carbonate for PVC injection molding materials, which comprises the following steps: S1, preparation of a nano calcium carbonate suspension: diluting 100 parts of lime milk after standing for 48 hours, adjusting the specific gravity to 1.060-1.080, cooling to room temperature, and then conveying to a bubbling carbonation reaction kettle with the volume of 60 m < 3 >; the prepared nano calcium carbonate has the advantages of being good in dispersity and processability, low in oil absorption value, high in thixotropy, high in activation rate, good in stability, close to neutral in pH value, uniform in particle size and the like, the rigidity, toughness, smoothness, bending strength and other performance of PVC can be improved when the nano calcium carbonate is used with PVC, the requirement for reaction conditions is not high through the method, the production cost is low, and the method is suitable for industrial production. The method is simple in process, easy to operate, low in energy consumption, high in synthesis efficiency and easy for industrial production, has good economic benefits, social benefits and ecological benefits, and is widely applied to coatings, rubber, medicines and cosmetics.

Description

Technical Field

[0001] The invention relates to the technical field related to transformer heat dissipation, in particular to a modification method of nano calcium carbonate special for PVC injection molding material. Background Art

[0002] Calcium carbonate is an inorganic non-metallic material with a very wide range of applications. Nano-calcium carbonate products, in particular, are widely used in rubber, plastic, sealant, automotive primer, coating, ink, papermaking, food, medicine and other fields due to their easy availability of raw materials, low price, high whiteness, excellent performance, low pollution in the production process, and good filling and processing performance. In industrial production, nano-calcium carbonate is usually prepared by the carbonation method. The nano-calcium carbonate prepared by this method is very prone to dissolution, recrystallization and alkali return of calcium carbonate particles during storage. The dissolution, recrystallization and alkali return of calcium carbonate particles will affect the morphology, particle size distribution and treatment effect of the nano-calcium carbonate product to a certain extent.

[0003] In addition, PVC's non-flammability, corrosion resistance, high strength, wear resistance, climate change resistance, insulation and excellent geometric stability make PVC one of the raw materials for various plastic products; however, PVC's flow properties are quite poor and its process range is very narrow, so lubricants are usually added to improve its flow properties.

[0004] Most of the existing modification methods of nano-calcium carbonate use higher fatty acids and dispersants to treat the surface of nano-calcium carbonate, but the emulsification degree and dispersibility of fatty acids are not good, the lipophilicity and hydrophobicity are insufficient, and the lubricant is easy to precipitate, resulting in the problem that nano-calcium carbonate is still not well compatible with polymer materials. In order to solve such problems, a modification method of nano-calcium carbonate specifically for PVC injection molding is proposed. Summary of the invention

[0005] The technical problem to be solved by the present invention is to solve the problem that most existing modification inventions will lead to poor fusion effect of nano calcium carbonate and other materials; in order to overcome the above problems, a modification method of nano calcium carbonate specially used for PVC injection molding material is provided, which solves the above problems.

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

[0007] A modification method of nano calcium carbonate for PVC injection molding material, the steps are as follows:

[0008] S1: Preparation of nano calcium carbonate suspension: dilute 100 parts of lime milk after standing for 48 hours, adjust the specific gravity to 1.060-1.080, cool to room temperature, and then transport to a 60m3 bubbling carbonation reactor, pass a purified, cooled and controlled temperature of 15-20℃ mixed gas containing air and carbon dioxide for carbonation reaction, and control the flow rate to 5-8m 3 / h, when the pH of the solution drops below 7, the carbonation reaction is completed, and the specific surface area of ​​calcium carbonate is controlled at 18-22m 2 / g to obtain a nano calcium carbonate suspension;

[0009] S2: Preparation of surface modifier: Heat water to 80-90°C, add 6-10 parts of liquid alkali, fully dissolve, add 6-8 parts of saturated fatty acid with 16-18 carbon atoms or 20-24 carbon atoms to carry out saponification reaction, stir for 10-30 minutes, and obtain saturated fatty acid saponification liquid; then add 4-4.5 parts of phenyl ester and 7-8 parts of alkanol, stir for 25-30 minutes, and obtain surface modifier;

[0010] S3: Surface modification treatment: heating the nano calcium carbonate suspension to 50-70°C, stirring continuously at a speed of 300 r / min, adding a surface modifier, and then adding a wetting agent for coating modification, stirring for 50-80 min, to obtain a modified nano calcium carbonate suspension;

[0011] S4: Modified nano-calcium carbonate: Cool the modified nano-calcium carbonate suspension, filter it, and obtain a crude modified nano-calcium carbonate product; dry it in an oven at 110-130° C., crush it, and sieve it to obtain the modified nano-calcium carbonate for PVC injection molding.

[0012] Preferably, the saturated fatty acid soap with 16 to 18 carbon atoms is one or a mixture of palmitic acid, lauric acid, and stearic acid; the saturated fatty acid soap with 20 to 24 carbon atoms is one or a mixture of arachidic acid, behenic acid, and lignoceric acid.

[0013] Preferably, the liquid alkali is one of 14-17% sodium hydroxide or calcium hydroxide.

[0014] Preferably, the phenyl ester is one or a mixture of phenyl chloroformate, phenyl acetate and benzyl benzoate.

[0015] Preferably, the alkanol is one or a mixture of tridecanol, 3-hexadecanol, octadecyl alcohol, octacosanol.

[0016] Preferably, the wetting agent is one or more combinations of sodium dodecylbenzene sulfonate, sodium polyacrylate, diglycerol polypropylene glycol ether, and fatty alcohol polyoxyethylene ether.

[0017] Preferably, the content of carbon dioxide in the mixed gas is 30% to 35%.

[0018] The advantages and positive effects of the present invention are as follows: the nano calcium carbonate prepared by the present invention has the advantages of good dispersibility and processing performance, low oil absorption value, high thixotropy, high activation rate, good stability, pH value close to neutrality, uniform particle size, etc., and can improve the rigidity, toughness, smoothness, bending strength and other properties of PVC when used with PVC. The method has low requirements on reaction conditions, low production cost, simple process, easy operation, low energy consumption, high synthesis efficiency, easy industrial production, good economic benefits, social benefits and ecological benefits, and is widely used in coatings, rubber, medicine and cosmetics. DETAILED DESCRIPTION

[0019] The present invention will now be described in further detail.

[0020] The embodiments of the present invention are further described below:

[0021] Calcium carbonate is an inorganic non-metallic material with a very wide range of applications. Nano-calcium carbonate products, in particular, are widely used in rubber, plastic, sealant, automotive primer, coating, ink, papermaking, food, medicine and other fields due to their easy availability of raw materials, low price, high whiteness, excellent performance, low pollution in the production process, and good filling and processing performance. In industrial production, nano-calcium carbonate is usually prepared by the carbonation method. The nano-calcium carbonate prepared by this method is very prone to dissolution, recrystallization and alkali return of calcium carbonate particles during storage. The dissolution, recrystallization and alkali return of calcium carbonate particles will affect the morphology, particle size distribution and treatment effect of the nano-calcium carbonate product to a certain extent.

[0022] In addition, PVC's non-flammability, corrosion resistance, high strength, wear resistance, climate change resistance, insulation and excellent geometric stability make PVC one of the raw materials for various plastic products; however, PVC's flow properties are quite poor and its process range is very narrow, so lubricants are usually added to improve its flow properties.

[0023] Most of the existing modification methods of nano calcium carbonate use advanced fatty acids and dispersants to treat the surface of nano calcium carbonate, but the emulsification degree and dispersibility of fatty acids are not good, the lipophilicity and hydrophobicity are insufficient, and the lubricant is easy to precipitate, resulting in the problem that nano calcium carbonate is still not well compatible with polymer materials. In order to solve this problem, a modification method of nano calcium carbonate for PVC injection molding is proposed; the steps are as follows:

[0024] S1: Preparation of nano calcium carbonate suspension: dilute 100 parts of lime milk after standing for 48 hours, adjust the specific gravity to 1.060-1.080, cool to room temperature, and then transport to a 60m3 bubbling carbonation reactor, pass a purified, cooled and controlled temperature of 15-20℃ mixed gas containing air and carbon dioxide for carbonation reaction, and control the flow rate to 5-8m 3 / h, when the pH of the solution drops below 7, the carbonation reaction is completed, and the specific surface area of ​​calcium carbonate is controlled at 18-22m 2 / g to obtain a nano calcium carbonate suspension;

[0025] S2: Preparation of surface modifier: Heat water to 80-90°C, add 6-10 parts of liquid alkali, fully dissolve, add 6-8 parts of saturated fatty acid with 16-18 carbon atoms or 20-24 carbon atoms to carry out saponification reaction, stir for 10-30 minutes, and obtain saturated fatty acid saponification liquid; then add 4-4.5 parts of phenyl ester and 7-8 parts of alkanol, stir for 25-30 minutes, and obtain surface modifier;

[0026] S3: Surface modification treatment: heating the nano calcium carbonate suspension to 50-70°C, stirring continuously at a speed of 300 r / min, adding a surface modifier, and then adding a wetting agent for coating modification, stirring for 50-80 min, to obtain a modified nano calcium carbonate suspension;

[0027] S4: Modified nano calcium carbonate: Cool the modified nano calcium carbonate suspension, filter it to obtain a crude modified nano calcium carbonate product; dry it in an oven at 110-130°C, crush it, and sieve it to obtain modified nano calcium carbonate for PVC injection molding; the nano calcium carbonate prepared by the present invention has the advantages of good dispersibility and processing performance, low oil absorption value, high thixotropy, high activation rate, good stability, pH value close to neutral, uniform particle size, etc., and when used with PVC, it can improve the rigidity, toughness, smoothness, bending strength and other properties of PVC. The method has low requirements on reaction conditions, low production cost, simple process, easy operation, low energy consumption, high synthesis efficiency, easy industrial production, good economic benefits, social benefits and ecological benefits, and is widely used in coatings, rubber, medicine, and cosmetics.

[0028] It should be noted that in this case, five groups of embodiments are used to reflect the performance test results, as follows: Embodiment 1:

[0029] 1. Preparation of nano calcium carbonate suspension: dilute 100 parts of lime milk after standing for 48 hours, adjust the specific gravity to 1.040, cool to room temperature, and then transport to a 60m3 bubbling carbonation reactor, pass a purified, cooled and controlled temperature of 17°C mixed gas containing air and carbon dioxide for carbonation reaction, and control the flow rate to 6m3 / h, the volume content of carbon dioxide is 38%, when the pH of the solution drops below 7, the carbonation reaction is completed, and the surface area is 22m 2 / g nano calcium carbonate suspension;

[0030] 2. Preparation of surface modifier: Heat water to 90°C, add 7 parts of 14% sodium hydroxide, and after fully dissolving, add 4 parts of palmitic acid, 2 parts of lauric acid, and 2 parts of stearic acid for saponification reaction, stir for 20 minutes, and obtain saturated fatty acid saponification liquid; then add 1.2 parts of phenyl chloroformate, 3 parts of benzyl stupid ester, 3 parts of tridecanol, and 5 parts of 3-hexadecanol, stir for 25 minutes to obtain a surface modifier.

[0031] 3. Surface modification: The nano calcium carbonate suspension was heated to 55°C and stirred continuously at a speed of 300 r / min, a surface modifier was added, and then sodium metasilicate pentahydrate was added for coating modification, and stirred for 50 min to obtain a modified nano calcium carbonate suspension;

[0032] 4. Modified nano-calcium carbonate: Cool the modified nano-calcium carbonate suspension, filter it, and obtain a crude modified nano-calcium carbonate product; dry it in an oven at 115°C, crush it with a vortex grinder, and sieve it to obtain the modified nano-calcium carbonate for PVC injection molding.

[0033] Embodiment 2:

[0034] 1. Preparation of nano calcium carbonate suspension: dilute 100 parts of lime milk after standing for 48 hours, adjust the specific gravity to 1.060, cool to room temperature, and then transport to a 60m3 bubbling carbonation reactor, pass a purified, cooled and controlled temperature of 20°C mixed gas containing air and carbon dioxide for carbonation reaction, and control the flow rate to 8m 3 / h, the volume content of carbon dioxide is 35%, when the pH of the solution drops below 7, the carbonation reaction is completed, and the surface area is 20m 2 / g nano calcium carbonate suspension;

[0035] 2. Preparation of surface modifier: Heat water to 85°C, add 9 parts of 16% calcium hydroxide, and after fully dissolving, add 1.5 parts of palmitic acid and 4.5 parts of stearic acid to carry out saponification reaction, stir for 25 minutes, and obtain saturated fatty acid saponification liquid; then add 4.5 parts of phenyl acetate, 3.5 parts of octadecyl alcohol, and 4 parts of octacosanol, and stir for 30 minutes to obtain a surface modifier;

[0036] 3. Surface modification: The nano calcium carbonate suspension was heated to 70°C and stirred continuously at a speed of 300 r / min, a surface modifier was added, and then sodium metasilicate pentahydrate was added for coating modification, and stirred for 70 min to obtain a modified nano calcium carbonate suspension;

[0037] 4. Modified nano-calcium carbonate: Cool the modified nano-calcium carbonate suspension, filter it, and obtain a crude modified nano-calcium carbonate product; dry it in an oven at 120°C, crush it with a vortex grinder, and sieve it to obtain the modified nano-calcium carbonate for PVC injection molding.

[0038] Embodiment 3:

[0039] 1. Preparation of nano calcium carbonate suspension: dilute 100 parts of lime milk after standing for 48 hours, adjust the specific gravity to 1.050, cool to room temperature, and then transport to a 60m3 bubbling carbonation reactor, pass a purified, cooled and controlled temperature of 19°C mixed gas containing air and carbon dioxide for carbonation reaction, and control the flow rate to 7m 3 / h, the volume content of carbon dioxide is 37%, when the pH of the solution drops below 7, the carbonation reaction is completed, and the surface area is 21m 2 / g nano calcium carbonate suspension;

[0040] 2. Preparation of surface modifier: Heat water to 80°C, add 8 parts of 15% sodium hydroxide, and after fully dissolving, add 2 parts of lauric acid and 5 parts of stearic acid for saponification reaction, stir for 15 minutes to obtain saturated fatty acid saponification liquid; then add 4.3 parts of benzyl benzoate, 3.4 parts of 3-hexadecanol, and 4.3 parts of octadecyl alcohol, stir for 30 minutes to obtain a surface modifier;

[0041] 3. Surface modification: The nano calcium carbonate suspension was heated to 65°C and stirred continuously at a speed of 300 r / min, a surface modifier was added, and then sodium metasilicate pentahydrate was added for coating modification, and stirred for 75 minutes to obtain a modified nano calcium carbonate suspension;

[0042] 4. Modified nano-calcium carbonate: Cool the modified nano-calcium carbonate suspension, filter it, and obtain a crude modified nano-calcium carbonate product; dry it in an oven at 130°C, crush it with a vortex mill, and sieve it to obtain the modified nano-calcium carbonate for PVC injection molding.

[0043] Embodiment 4:

[0044] 1. Preparation of nano calcium carbonate suspension: dilute 100 parts of lime milk after standing for 48 hours, adjust the specific gravity to 1.030, cool to room temperature, and then transport to a 60m3 bubbling carbonation reactor, pass a purified, cooled and controlled temperature of 15°C mixed gas containing air and carbon dioxide for carbonation reaction, and control the flow rate to 5m 3 / h, the volume content of carbon dioxide is 36%, when the pH of the solution drops below 7, the carbonation reaction is completed and the surface area is 19m 2 / g nano calcium carbonate suspension;

[0045] 2. Preparation of surface modifier: Heat water to 87°C, add 10 parts of 17% calcium hydroxide, fully dissolve, add 8 parts of palmitic acid for saponification reaction, stir for 20 minutes, and obtain saturated fatty acid saponification liquid; then add 4.4 parts of phenyl chloroformate and 7.1 parts of octacosanol, stir for 25 minutes, and obtain surface modifier;

[0046] 3. Surface modification: The nano calcium carbonate suspension was heated to 60°C and stirred continuously at a speed of 300 r / min, a surface modifier was added, and then sodium metasilicate pentahydrate was added for coating modification, and stirred for 60 min to obtain a modified nano calcium carbonate suspension;

[0047] 4. Modified nano-calcium carbonate: Cool the modified nano-calcium carbonate suspension, filter it, and obtain a crude modified nano-calcium carbonate product; dry it in an oven at 125°C, crush it with a vortex mill, and sieve it to obtain the modified nano-calcium carbonate for PVC injection molding.

[0048] Embodiment 5:

[0049] 1. Preparation of nano calcium carbonate suspension: dilute 100 parts of lime milk after standing for 48 hours, adjust the specific gravity to 1.040, cool to room temperature, and then transport to a 60m3 bubbling carbonation reactor, pass a purified, cooled and controlled temperature of 18°C ​​mixed gas containing air and carbon dioxide for carbonation reaction, and control the flow rate to 6m 3 / h, the volume content of carbon dioxide is 35%, when the pH of the solution drops below 7, the carbonation reaction is completed, and the surface area is 18m 2 / g nano calcium carbonate suspension;

[0050] 2. Preparation of surface modifier: Heat water to 84°C, add 6 parts of 14% calcium hydroxide, and after fully dissolving, add 4.7 parts of palmitic acid and 3.4 parts of lauric acid for saponification reaction, stir for 25 minutes to obtain saturated fatty acid saponification liquid; then add 4-phenyl acetate and 7.3 parts of tridecanol, stir for 25 minutes to obtain a surface modifier;

[0051] 3. Surface modification: Heat the nano calcium carbonate suspension to 50°C and stir it continuously at a speed of 300 r / min, add the surface modifier, then add sodium metasilicate pentahydrate for coating modification, and stir for 65 minutes.

Claims

1. A modification method of nano calcium carbonate for PVC injection molding. Features: Here are the steps: S1: Preparation of nano calcium carbonate suspension: dilute 100 parts of lime milk after standing for 48 hours, adjust the specific gravity to 1.060-1.080, cool to room temperature, and then transport to a 60m3 bubbling carbonation reactor, pass a purified, cooled and controlled temperature of 15-20℃ mixed gas containing air and carbon dioxide for carbonation reaction, and control the flow rate to 5-8m 3 / h, when the pH of the solution drops below 7, the carbonation reaction is completed, and the specific surface area of ​​calcium carbonate is controlled at 18-22m 2 / g to obtain a nano calcium carbonate suspension; S2: Preparation of surface modifier: Heat water to 80-90°C, add 6-10 parts of liquid alkali, fully dissolve, add 6-8 parts of saturated fatty acid with 16-18 carbon atoms or 20-24 carbon atoms to carry out saponification reaction, stir for 10-30 minutes, and obtain saturated fatty acid saponification liquid; then add 4-4.5 parts of phenyl ester and 7-8 parts of alkanol, stir for 25-30 minutes, and obtain surface modifier; S3: Surface modification treatment: heating the nano calcium carbonate suspension to 50-70°C, stirring continuously at a speed of 300 r / min, adding a surface modifier, and then adding a wetting agent for coating modification, stirring for 50-80 min, to obtain a modified nano calcium carbonate suspension; S4: Modified nano-calcium carbonate: Cool the modified nano-calcium carbonate suspension, filter it, and obtain a crude modified nano-calcium carbonate product; dry it in an oven at 110-130° C., crush it, and sieve it to obtain the modified nano-calcium carbonate for PVC injection molding.

2. The modification method of nano calcium carbonate for PVC injection molding material according to claim 1, Features: The saturated fatty acid soap with carbon atoms of 16 to 18 is one or a mixture of palmitic acid, lauric acid and stearic acid; the saturated fatty acid soap with carbon atoms of 20 to 24 is one or a mixture of arachidic acid, behenic acid and lignoceric acid.

3. The modification method of nano calcium carbonate for PVC injection molding according to claim 1, Features: The liquid alkali is one of 14-17% sodium hydroxide or calcium hydroxide.

4. The modification method of nano calcium carbonate for PVC injection molding material according to claim 1, Features: The phenyl ester is one or a mixture of phenyl chloroformate, phenyl acetate and benzyl stupid ester.

5. The modification method of nano calcium carbonate for PVC injection molding material according to claim 1, Features: The alkanol is one or a mixture of tridecanol, 3-hexadecanol, octadecyl alcohol, octacosanol.

6. The modification method of nano calcium carbonate for PVC injection molding material according to claim 1, Features: The wetting agent is one or more combinations of sodium dodecylbenzene sulfonate, sodium polyacrylate, diglycerol polypropylene glycol ether, and fatty alcohol polyoxyethylene ether.

7. The modification method of nano calcium carbonate for PVC injection molding material according to claim 1, Features: The content of carbon dioxide in the mixed gas is 30% to 35%.