KR20220096999A - Calcium carbonate composite materials and thermoplastic resin composition comprising the same - Google Patents

Abstract

The present invention relates to a calcium carbonate composite material which comprises calcium carbonate, and a coating layer formed on the calcium carbonate, wherein the coating layer includes an acrylic resin having a weight average molecular weight of 2,000 to 10,000 g/mol. A thermoplastic resin composition including the calcium carbonate composite material has excellent internal dispersibility during extrusion, thereby having excellent mechanical strength of the manufactured cured product.

Description

Calcium carbonate composite and thermoplastic resin composition comprising the same

The present invention relates to a calcium carbonate composite having excellent compatibility with a polyvinyl chloride resin, and a thermoplastic resin composition comprising the same.

Polyvinyl chloride (PVC) resin has excellent physical and chemical properties and is widely used in various fields such as pipes, building materials, electric wires, cables, and films. However, a composition including a PVC resin generally includes a filler to improve mechanical properties such as hardness and/or strength of a cured product prepared therefrom. At this time, as a filler, fumed silica, calcium carbonate, etc. are widely used.

Fumed silica can easily adjust the viscosity of the composition even when added in a small amount, but has high thixotropic properties (thixotropic properties), and there is a limit in that the viscosity of the composition is extremely changed even with a small difference in the amount added. On the other hand, calcium carbonate has the advantage of being able to impart high thixotropy to the composition at a relatively low cost, and improving the mechanical properties of a cured product prepared from the composition including the same. In this case, it is common to surface-treat the calcium carbonate to improve compatibility with the resin and ease of viscosity control of a composition comprising the same.

Specifically, in Korean Patent Registration No. 623906 (Patent Document 1), without the use of an emulsifier or surfactant, the surface of calcium carbonate in an aqueous system heated to a temperature above the melting point of the surface-treating agent is wet-surface with a hydrophobic surface-treating agent. A -treated surface-treated calcium carbonate filler is disclosed. However, as in Patent Document 1, the conventional method for surface treatment of calcium carbonate in which the surface is treated in a wet manner has disadvantages in that most of the processes are complicated and the process cost is high.

Therefore, the dry surface treatment process is simple, and the surface-treated calcium carbonate has excellent dispersibility and excellent compatibility with the resin. There is a need for R&D.

Korean Patent Registration No. 623906 (published on January 1, 2001)

Accordingly, in the present invention, the dry surface treatment process is simple, the surface-treated calcium carbonate has excellent dispersibility and excellent compatibility with the resin, and thus a calcium carbonate composite material having excellent mechanical strength of a cured product and a thermoplastic resin comprising the same It is intended to provide a composition.

The present invention is calcium carbonate; and a coating layer formed on the calcium carbonate;

The coating layer provides a calcium carbonate composite comprising an acrylic resin having a weight average molecular weight of 2,000 to 10,000 g/mol.

In addition, the present invention provides a thermoplastic resin composition comprising the calcium carbonate composite, and a polyvinyl chloride resin.

The calcium carbonate composite according to the present invention undergoes a simple dry surface treatment process, and has excellent dispersibility and compatibility with resin.

In addition, the thermoplastic resin composition including the calcium carbonate composite material has excellent internal dispersibility during extrusion and thus has excellent mechanical strength of the prepared cured product.

Hereinafter, the present invention will be described in detail.

In the present specification, the "weight average molecular weight" of the resin may be measured by a method well known in the art, for example, may represent a value measured by a method such as GPC (gel permeation chromatograph).

In addition, the functional group such as "acid value (Av)" of the resin can be measured by a method well known in the art, for example, it can be measured by a method such as titration (titration).

In addition, in this specification, "(meth)acryl" means "acryl" and/or "methacrylic", and "(meth)acrylate" means "acrylate" and/or "methacrylate" .

In the present specification, "degree of polymerization" is the number of repeating units in the polymer, and can be calculated or measured by methods well known in the art, such as ASTM D1 243-79.

Calcium Carbonate Composite

Calcium carbonate composite according to the present invention is calcium carbonate; and a coating layer formed on the calcium carbonate.

calcium carbonate

Calcium carbonate may have a spherical shape, needle shape, plate shape, scale shape, hollow shape, irregular shape, hexagonal shape, cubic shape, flake shape, etc., specifically, may be plate shape.

In addition, the calcium carbonate may have a particle size (D97) of 1.0 to 4.0 μm, or 3.0 to 4.0 μm. When the particle size (D97) of the calcium carbonate is less than the above range, there is a problem in that the productivity of the calcium carbonate decreases and the specific surface area increases to increase the thickness of the coating layer, and when it exceeds the above range, the dispersibility of the calcium carbonate in the thermoplastic resin is is lowered, and the crack propagation pathway may be reduced, so that the impact strength of the prepared cured product may be reduced.

In this case, D97 means the particle size of calcium carbonate when the cumulative degree is 97% in the volume cumulative particle size distribution. Specifically, in the graph (volume-based particle size distribution) in which the particle size is on the horizontal axis and the frequency of volume accumulation from the side with the smallest particle size on the vertical axis, the volume % from the smallest particle diameter with respect to the volume cumulative value (100%) of all particles The particle diameter of which the cumulative value of is 97% corresponds to D97. The cumulative volume particle size distribution of the calcium carbonate may be measured using a laser diffraction scattering particle size distribution device.

coating layer

The coating layer is formed on the surface of the calcium carbonate, and serves to improve the dispersibility of the calcium carbonate, thereby improving the mechanical strength of the molded article.

<Acrylic resin>

The coating layer includes an acrylic resin.

The acrylic resin may be directly synthesized according to a known method, or a commercially available product may be used. For example, the acrylic resin may be prepared by polymerizing a (meth)acrylate-based monomer.

The (meth) acrylate-based monomer is, for example, (meth) acrylic acid, methyl (meth) acrylic acid, (meth) acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate , isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, isooctyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isodecyl (meth) acrylate, n-decyl (meth) acrylate, n-dodecyl (meth) acrylate, isobornyl (meth) acrylate, lauryl (meth) acrylate, 2-hydroxymethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2- It may include at least one selected from the group consisting of hydroxy propyl (meth) acrylate and 2-hydroxy butyl (meth) acrylate.

The acrylic resin may not contain a solvent. That is, the acrylic resin may be prepared by, for example, polymerizing the resin composition including the (meth)acrylate-based monomer and the solvent and then removing the solvent. In this case, the removal of the solvent may be generally performed by removing the solvent through reduced pressure after polymerization of the resin. In addition, when the acrylic resin contains a solvent, safety problems and environmental problems may occur for workers due to volatilization of the solvent during the coating process, and there may be problems in that the mechanical strength of the manufactured molded article is lowered due to the residual solvent.

In addition, the acrylic resin may have a solid content of 80 to 100% by weight, or 90 to 100% by weight, based on the total weight of the resin. When the solid content of the acrylic resin is less than the above range, the residual solvent in the high-temperature extrusion process is present as bubbles in the molded article, which may cause a problem in that the mechanical strength of the molded article is lowered.

The acrylic resin may have a weight average molecular weight (Mw) of 2,000 to 10,000 g/mol, or 2,500 to 5,000 g/mol. When the weight average molecular weight of the acrylic resin is less than the above range, the high boiling point solvent usage is high, making it difficult to remove after resin polymerization. In case of exceeding the above range, the viscosity of the resin is high, so that it is difficult to discharge the resin during spray coating, which may cause a problem of insufficient workability.

In addition, the acrylic resin may have an acid value (Av) of 50 to 150 mgKOH/g, or 70 to 120 mgKOH/g. When the acid value of the acrylic resin is less than the above range, the force to orient the acrylic resin toward the surface of calcium carbonate is reduced, and the bond with calcium carbonate is broken by thermal energy during extrusion, thereby reducing the dispersibility and compatibility of calcium carbonate in the thermoplastic resin , and when it exceeds the above range, the viscosity of the resin is high, so it is difficult to discharge the resin during spray coating, which may cause a problem of insufficient workability.

<Unsaturated fatty acid>

The coating layer may further include an unsaturated fatty acid.

In this case, the unsaturated fatty acid serves to control the viscosity of the composition and improve the hydrophobicity of the acrylic resin to improve the surface adhesion rate of the acrylic resin to calcium carbonate.

The unsaturated fatty acid may include at least one selected from the group consisting of tall oil fatty acid, linseed oil fatty acid, safflower oil fatty acid, sunflower oil fatty acid, soy milk fatty acid, dehydrated castor oil fatty acid, linoleic acid, and ricinoleic acid. Specifically, the unsaturated fatty acid may include tall oil fatty acid.

The acrylic resin and the unsaturated fatty acid may be included in a weight ratio of 5:5 to 8:2, or 6:4 to 7:3 by weight. When the weight ratio of the acrylic resin and the unsaturated fatty acid is less than the above range, that is, when an excess of unsaturated fatty acid is included based on the acrylic resin, there is a problem in that the molded article manufactured due to the brown component of the unsaturated fatty acid is out of the standard color range, and the above range In the case of excess, that is, when a small amount of unsaturated fatty acid is included based on the acrylic resin, the process temperature cannot be reduced compared to the process without applying the unsaturated fatty acid, so there is no additional effect of the unsaturated fatty acid.

The coating layer may be prepared by dry coating the coating composition and then drying. For example, the coating layer may be prepared by dry coating the coating composition at 70 to 140 ℃ and then drying at 60 to 100 ℃. In this case, the dry coating may be performed by a method selected from the group consisting of, for example, spray coating, a ball mill, a mixer, and a revolving mixer. In addition, the drying may be performed, for example, by a method selected from the group consisting of pin mill drying, ball mill drying, and oven drying.

In addition, when the dry coating temperature is less than the above range, there is a problem that the particle size of the coating layer increases during coating so that the surface of the coating layer is not uniform. have.

When the drying temperature is less than the above range, the fluidity of the coating composition decreases and agglomeration occurs in the coating layer, and when it exceeds the above range, a problem of calcium carbonate detaching from the coating composition may occur.

As described above, the calcium carbonate composite according to the present invention undergoes a simple dry surface treatment process, and has excellent dispersibility and compatibility with polyvinyl chloride resin.

Thermoplastic resin composition

The thermoplastic resin composition according to the present invention includes the calcium carbonate composite and polyvinyl chloride resin as described above.

Calcium Carbonate Composite

The calcium carbonate composite material serves to improve mechanical properties such as strength and hardness of the molded article.

In addition, the calcium carbonate composite material may be included in the composition in an amount of 5 to 25 parts by weight, or 7 to 20 parts by weight based on 60 to 85 parts by weight of the polyvinyl chloride resin. When the content of the calcium carbonate composite is less than the above range, the mechanical strength improvement effect, which is an effect due to the calcium carbonate composite, may be insufficient, and the mechanical strength of the molded article may be insufficient. The surface smoothness of the composition is reduced, and the viscosity of the composition is excessively high, which may cause a problem in that the extrusion moldability is lowered.

polyvinyl chloride resin

The polyvinyl chloride resin serves to form a molded article as the main resin.

The polyvinyl chloride (PVC) resin may have a polymerization degree of 700 to 1,100, or 800 to 1,000. When the polymerization degree of the polyvinyl chloride resin is less than the above range, a problem of lowering the strength of the molded article may occur.

The polyvinyl chloride resin may have a chlorine content of 40 to 70 wt%, or 50 to 60 wt%, based on the total weight of the resin. When the chlorine content of the polyvinyl chloride resin is less than the above, there is a problem in that the heat resistance, strength and corrosion resistance of the manufactured molded article decrease, and when it exceeds the above range, the glass transition temperature of the resin increases, making it difficult to manufacture the molded article. can occur

In addition, the polyvinyl chloride resin may be included in the composition in an amount of 60 to 85 parts by weight, or 65 to 80 parts by weight, based on 5 to 20 parts by weight of the calcium carbonate composite. When the content of the polyvinyl chloride resin is less than the above range, there is a problem in that thermal workability is lowered, the load in the screw increases in the extrusion process, and the dimensional accuracy of the molded article decreases, and when it exceeds the above range, the content of the filler is relatively This may cause a problem in that the strength of the molded article decreases.

additive

The thermoplastic resin composition may further include additives that can be added to the thermoplastic resin composition, such as impact modifiers, fillers, stabilizers, and pigments.

At this time, the type of the additive is not particularly limited as long as it can be added to the conventional thermoplastic composition. In addition, the content of the additive may be included in the composition in an amount of 5 to 25 parts by weight, or 10 to 20 parts by weight based on 60 to 85 parts by weight of the polyvinyl chloride resin.

As described above, the thermoplastic resin composition according to the present invention has excellent internal dispersibility during extrusion and thus has excellent mechanical strength of the prepared cured product.

molded product

The present invention provides a molded article prepared from the thermoplastic resin composition as described above.

In this case, the molded article may be manufactured by extruding the thermoplastic resin composition, for example, may be windows. The extrusion conditions are not particularly limited as long as they are generally applicable conditions when manufacturing a thermoplastic molded article.

As described above, the molded article according to the present invention has excellent mechanical properties such as tensile strength and tensile elongation.

Hereinafter, the present invention will be described in more detail through examples. However, these examples are only for helping the understanding of the present invention, and the scope of the present invention is not limited to these examples in any sense.

[Example]

Preparation Example 1. Preparation of acrylic resin-1

In a reaction vessel, 28.6 parts by weight of xylene, 8.57 parts by weight of acrylic acid, 52.98 parts by weight of 2-ethylhexyl acrylate (2-EHA), and tert-Butyl peroxy-2-ethylhexanoate (tert-Butyl peroxy) as a thermal initiator -2-ethylhexanoate) was added in 9.85 parts by weight and polymerized at 135° C. until the weight average molecular weight (Mw) became 2,835 g/mol to prepare an acrylic resin.

Thereafter, xylene as a solvent was removed under vacuum to prepare an acrylic resin-1 having a solid content of 98.5 wt%, a weight average molecular weight of 2,699 g/mol, and an acid value (Av) of 100 mgKOH/g.

Preparation Example 2 to Preparation Example 7. Preparation of acrylic resin

Each component was adjusted as shown in Table 1 to prepare an acrylic resin.

Ingredients (parts by weight) Preparation Example 1 Preparation 2 Preparation 3 Preparation 4 Preparation 5 Preparation 6 Preparation 7 xylene 28.6 28.6 28.6 26.82 30.17 28.77 28.65 acrylic acid 8.57 8.57 8.57 8.53 8.67 4.31 12.88 2-EHA 52.98 52.98 52.98 49.66 55.89 57.33 48.73 thermal initiator 9.85 9.85 9.85 14.99 5.27 9.59 9.74 acrylic resin Solid content (% by weight) 98.5 97.2 70.2 97.8 97.5 99.1 98.3 Mw (g/mol) 2,699 4,824 2,835 1,527 11,576 2,802 2,722 Av(mgKOH/g) 100 100 100 100 100 45 160

Example 1. Preparation of thermoplastic resin composition

1-1: Preparation of calcium carbonate composite

On the surface of calcium carbonate (particle size (D97): 3.6 µm, plate-like), the acrylic resin from which the solvent of Preparation Example 1 was removed was spray-coated at 110 ° C., and pin-milled at 80 ° C. to form a coating layer having an average thickness of 4 nm. , to prepare a calcium carbonate composite.

1-2: Preparation of thermoplastic resin composition and molded article

75.9 parts by weight of polyvinyl chloride resin (PVC, degree of polymerization: 1,000, chlorine content: 57% by weight) in a reaction vessel, 10.7 parts by weight of the calcium carbonate composite of 1-1 above, chlorinated polyethylene (CPE, weight average molecular weight: 450,000) as an impact modifier g/mol, chlorine content: 40% by weight) 5 parts by weight, titanium dioxide (TiO ₂ ) 3 parts by weight as a pigment, and 5.4 parts by weight of calcium stearate as a stabilizer to prepare a thermoplastic resin composition.

Thereafter, an extrusion die and an adapter were mounted on the extruder to prepare an extrusion device for extruding the molded article, and the thermoplastic resin composition was put into the extruder to plasticize the PVC and molded to prepare a molded article having a thickness of 2.0 mm and a width of 100 mm. . At this time, the temperature of the barrel of the extruder was to be 165 ℃, 170 ℃ and 170 ℃, the temperature of the adapter was maintained at 170 ℃, the temperature of the extrusion die was maintained at 180 ℃. The manufactured molded article was naturally cooled at room temperature.

Examples 2 to 8, and Comparative Example 1 and Comparative Example 2.

As shown in Tables 2 and 3, a molded article was manufactured in the same manner as in Example 1, except that the type of the acrylic resin was changed. In this case, tall oil fatty acid (manufacturer: Jungwoo Chemical, product name: SYLFAT FA2) was used as the unsaturated fatty acid.

Ingredients (parts by weight) Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Example 4 Example 5 Acrylic resin of Preparation Example 1 100 - - - - - - Acrylic resin of Preparation Example 2 - 100 - - - - - Acrylic resin of Preparation Example 3 - - 100 - - - - Acrylic resin of Preparation Example 4 - - - 100 - - - Acrylic resin of Preparation Example 5 - - - - 100 - - Acrylic resin of Preparation Example 6 - - - - - 100 - Acrylic resin of Preparation Example 7 - - - - - - 100

Ingredients (parts by weight) Example 6 Example 7 Example 8 Acrylic resin of Preparation Example 1 70 45 90 unsaturated fatty acids 30 55 10

experimental example. Characteristics evaluation of molded products

The properties of the molded articles prepared in Examples and Comparative Examples were measured in the following manner, and the results are shown in Table 4.

(1) Tensile strength and tensile elongation

The tensile strength and tensile elongation were measured according to the 6.6 tensile strength test method for synthetic resin windows and doors according to KSF5602.

(2) color difference

Color and color difference were measured according to 6.4 Color difference test method for synthetic resin windows and doors according to KSF5602.

division tensile elongation The tensile strength Color difference (ΔE) (target) 130% or more 42 MPa or more 1.3 and below Example 1 135.95 43.62 0.53 Example 2 128.45 41.82 0.55 Example 3 101.38 38.99 0.58 Example 4 No coating layer No coating layer 0.61 Example 5 No coating layer No coating layer 0.59 Example 6 136.82 43.68 0.72 Example 7 134.23 41.33 1.41 Example 8 134.85 41.69 0.68 Comparative Example 1 108.62 40.10 0.54 Comparative Example 2 No coating layer No coating layer 0.61

As can be seen in Table 4, the molded article of Examples had excellent tensile strength and tensile elongation, and low color difference.

On the other hand, Comparative Example 1 using the acrylic resin of Preparation Example 4 having a low weight average molecular weight was insufficient in tensile elongation and tensile strength.

In addition, in Comparative Example 2 using the acrylic resin of Preparation Example 5 having a high weight average molecular weight, the resin had a high viscosity, so it was difficult to discharge the resin during spray coating, so a coating layer was not formed on the surface of the calcium carbonate, so mechanical properties such as tensile elongation and tensile strength could not be improved.

Claims (4)

calcium carbonate; and a coating layer formed on the calcium carbonate;
The coating layer is a calcium carbonate composite comprising an acrylic resin having a weight average molecular weight of 2,000 to 10,000 g/mol. The method according to claim 1,
The acrylic resin has an acid value of 50 to 150 mgKOH/g, and a solid content of 80 to 100% by weight based on the total weight of the resin, a calcium carbonate composite. The method according to claim 1,
The coating layer further comprises an unsaturated fatty acid,
The acrylic resin and the unsaturated fatty acid are included in a weight ratio of 5:5 to 8:2, a calcium carbonate composite. A thermoplastic resin composition comprising the calcium carbonate composite of any one of claims 1 to 3, and a polyvinyl chloride resin.