Surface-treated calcium carbonate filler, and resin composition and molded article using the same

Abstract

The surface-treated calcium carbonate of the present invention comprises surface-treated calcium carbonate particles that have been surface-treated with fatty acids and phosphoric acids, wherein the surface-treated calcium carbonate satisfies the following formulas (a), (b), and (c): (a) 3 ≤ Sw ≤ 20 (m 2 / g)(b)300≤Pw≤5000(ppm))(c)50≤Calcification rate≤95(mass%). Here, Sw is the BET specific surface area (m²) of the surface-treated calcium carbonate particles. 2 / g), Pw is the phosphorus content (ppm) in the surface-treated calcium carbonate particles measured by inductively coupled plasma optical emission spectrometry (ICP), and calcification rate is the percentage of the mass (g) of fatty acids constituting calcium fatty acids relative to the total surface treatment amount (g) of the surface-treated calcium carbonate particles.

Description

Technical Field

[0001] This invention relates to surface-treated calcium carbonate fillers, resin compositions and molded articles using the same, and more specifically, to surface-treated calcium carbonate fillers capable of improving the heat resistance of the resulting resin compositions, resin compositions and molded articles using the same.

[0002] Synthetic resin compositions such as polyolefin, polyester, polystyrene, and vinyl chloride are combined with inorganic pigments such as calcium carbonate due to their excellent rigidity, impact resistance, heat resistance, moldability, transparency, and chemical resistance. They are widely used in various industrial materials, automotive parts, containers for medical or cosmetic purposes, and various films and fibers for daily necessities or industrial applications.

[0003] Inorganic fillers are incorporated into these resin compositions for various purposes, such as imparting thermal stability, abrasion resistance, rigidity, impact resistance, and thixotropy. Here, for the resin products containing inorganic fillers to achieve the desired properties, it is necessary to ensure that the inorganic fillers are sufficiently dispersed in the resin composition. To this end, various modifications have been made to the mixing machinery and mixing conditions. Furthermore, various surface treatments are performed on the inorganic fillers themselves to improve their dispersibility in the resin composition. Surface treatment agents and methods used in these surface treatments have been investigated.

[0004] For example, porous membranes made from polyolefin resin compositions are manufactured by forming the polyolefin resin composition into a membrane and stretching it, utilizing the difference in mechanical properties between the polyolefin resin and the inorganic filler to create voids at the resin-filler interface. These porous membranes have been researched and developed for various applications, including synthetic paper, sanitary materials, medical materials, building materials, breathable sheets for agriculture, and battery separators, and some have already been put into practical use. However, to obtain membranes that perform at a higher level, it is desirable to have small dimensional deviations in the voids formed within the membrane and a uniform distribution of voids on the membrane surface. Furthermore, porous membranes tend to have poor heat resistance due to the large number of voids formed through stretching in their manufacturing process; therefore, improving heat resistance is desired.

[0005] Therefore, ensuring uniform dispersion of inorganic fillers in the resin composition is extremely important. However, if this dispersion relies solely on mechanical means, even if some degree of dispersion is achieved, there is a risk of the following problems: increased production costs; resin deterioration, leading to resin decomposition and the generation of gases and dust, resulting in a harsh working environment. Furthermore, if the resin composition lacks sufficient heat resistance, surface treatment agents and inorganic fillers remaining in the resin and / or resin composition during mixing and extrusion operations will char, forming aggregates (resin char) that clog the filter screen installed inside the extruder die. Fine-mesh filters are particularly prone to clogging in membrane applications. Replacing the filter screen requires manual labor and leads to waste of the resin composition used and lost manufacturing time, significantly increasing costs.

[0006] To address these issues, metal soaps such as calcium stearate, phenolic antioxidants, and phosphorus-based antioxidants have been added to these resins, resulting in improved stability of the resin compositions. Furthermore, the following procedure was performed: calcium carbonate treated with fatty acids such as stearic acid and stearic acid soap was added, thereby enabling calcium carbonate itself to enhance the stability of the resin composition.

[0007] To further improve upon this, Patent Document 1 describes an inorganic filler whose dispersibility in a resin composition is improved by surface treatment of inorganic particles using a combination of surfactants and chelating agents. Patent Documents 2 and 3 describe methods for removing aggregates through further combinations and processes such as classification.

[0008] The techniques described in these patent documents 1-3 all improve the dispersibility of surface-treated calcium carbonate. However, on the other hand, in the manufacture of this inorganic filler, the reaction between fatty acids and calcium ions is also hindered because the chelating compounds capture calcium ions. As a result, the proportion of calcium salts of the fatty acids produced decreases, and the residual proportion of fatty acids increases.

[0009] These fatty acids and their alkali metal salts are thermally unstable compared to calcium salts of fatty acids. Therefore, polyolefin resin compositions obtained using these surface-treated calcium carbonates sometimes fail to adequately meet requirements for heat resistance and durability.

[0010] Furthermore, by adding phenolic and phosphorus-based antioxidants to these resins, the resulting resin compositions can be stabilized. However, the amount of these antioxidants added is extremely small, and therefore, it has been pointed out that they are difficult to distribute uniformly throughout the resin, resulting in localized uneven concentrations.

[0011] In recent years, polyolefin resins have been known as relatively environmentally friendly resins, and there is anticipation for their use as substrates for environmental infrastructure applications. On the other hand, as mentioned above, they have been pointed out to have insufficient thermal stability, and there is a growing expectation for better heat resistance and durability.

[0012] Existing technical documents

[0013] Patent documents

[0014] Patent Document 1: Japanese Patent Application Publication No. 2002-363443

[0015] Patent Document 2: Japanese Patent Application Publication No. 2006-169421

[0016] Patent Document 3: International Publication No. 2007 / 088707 Summary of the Invention

[0017] The problem that the invention aims to solve

[0018] The present invention addresses the aforementioned problems and aims to provide a surface-treated calcium carbonate filler that can be dispersed substantially uniformly in a resin composition and impart high thermal stability to the resin composition, as well as a resin composition and a molded article using the same.

[0019] means for solving problems

[0020] This invention relates to a surface-treated calcium carbonate filler comprising surface-treated calcium carbonate particles treated with fatty acids and phosphoric acid, wherein the surface-treated calcium carbonate filler satisfies the following formulas (a), (b), and (c):

[0021] (a) 3 ≤ Sw ≤ 20 (m 2 / g)

[0022] (b) 300 ≤ Pw ≤ 5000 (ppm)

[0023] (c) 50 ≤ calcification rate ≤ 95 (mass%)

[0024] Sw represents the BET specific surface area (m²) of the surface-treated calcium carbonate particles. 2 / g),

[0025] Pw represents the phosphorus content (ppm) in the surface-treated calcium carbonate particles, measured using an inductively coupled plasma (ICP) luminescence spectrophotometer.

[0026] The calcification rate is the percentage of the mass (g) of the fatty acids constituting the calcium fatty acid to the total surface treatment amount (g) of the surface-treated calcium carbonate particles.

[0027] In one embodiment, the surface-treated calcium carbonate filler of the present invention also satisfies the following formulas (d), (e), and (f):

[0028] (d) 0.1 ≤ D50 ≤ 1.5 (μm)

[0029] (e) 0.9 ≤ (D90 - D10) / D50 ≤ 2.0

[0030] (f) Da≤5.0(μm)

[0031] Here, D50 is the 50% diameter (μm) accumulated from the small particle side of the volumetric particle size distribution of the aforementioned surface-treated calcium carbonate particles, as measured using a laser diffraction particle size distribution measuring device.

[0032] D90 is the 90% diameter (μm) accumulated from the small particle side of the volumetric particle size distribution of the surface-treated calcium carbonate particles, as measured using this laser diffraction particle size distribution measuring device.

[0033] D10 is the 10% diameter (μm) accumulated from the small particle side of the volumetric particle size distribution of the surface-treated calcium carbonate particles, as measured using this laser diffraction particle size distribution measuring device.

[0034] Da represents the maximum particle size (μm) in the volumetric particle size distribution of the surface-treated calcium carbonate particles, as measured using the laser diffraction particle size distribution measuring device.

[0035] In one embodiment, the fatty acids are at least one compound selected from saturated fatty acids and saturated fatty acid salts.

[0036] In one embodiment, the surface-treated calcium carbonate filler of the present invention is used to form a polyolefin resin composition.

[0037] In addition, the present invention is a resin composition containing resin and the above-mentioned surface-treated calcium carbonate filler.

[0038] In one embodiment, the resin is a polyolefin resin.

[0039] In addition, the present invention is a molded article, which is composed of the above-mentioned resin composition.

[0040] In one embodiment, the molded article of the present invention has a film morphology.

[0041] Invention Effects

[0042] According to the present invention, the resin composition exhibits good dispersibility in the resin composition and possesses excellent heat resistance. Therefore, the resin composition containing the surface-treated calcium carbonate filler of the present invention can suppress coking between the filler and the resin, and residual surface-treated agent, during operations such as compounding and extrusion, and prevents or reduces clogging of the filter screen installed inside the extruder die. Furthermore, the resin composition obtained in this manner also possesses excellent heat resistance. Detailed Implementation

[0043] 1. Surface-treated calcium carbonate filler

[0044] The surface-treated calcium carbonate filler of the present invention comprises surface-treated calcium carbonate particles, preferably composed of the surface-treated calcium carbonate particles as the main component.

[0045] (a) BET specific surface area (Sw)

[0046] In this invention, the surface-treated calcium carbonate particles have a specified BET specific surface area (Sw; m²) based on nitrogen adsorption. 2 / g). In this invention, the Sw of the surface-treated calcium carbonate particles is 3≤Sw≤20 (m 2 / g), preferably 4≤Sw≤16(m 2 / g), more preferably 5≤Sw≤12(m 2 / g). If the Sw of the surface-treated calcium carbonate particles is less than 3 (m 2 If the particle size ( / g) of the surface-treated calcium carbonate particles exceeds 20 (m), the primary particle size becomes too large, leading to a decrease in the strength of the resin composition when it is incorporated into the resin composition. Additionally, if the Sw of the surface-treated calcium carbonate particles exceeds 20 (m)... 2 If the concentration is less than 1 g, it is difficult to disperse it evenly in the resin composition.

[0047] (Method for determining Sw)

[0048] Sw of surface-treated calcium carbonate particles can be measured using, for example, Macsorb HM model-1201 manufactured by Macsorb Corporation, and as follows.

[0049] Specifically, 0.2–0.3 g of surface-treated calcium carbonate filler for testing is placed in the testing device as a pretreatment. After heating at 200°C for 10 minutes in a mixed atmosphere of nitrogen and helium, low-temperature and low-humidity physical adsorption is performed in a liquid nitrogen environment, thereby determining Sw.

[0050] Sw can be controlled by varying various conditions during the manufacture of surface-treated calcium carbonate particles constituting the filler of the present invention. Examples of conditions that enable Sw to be controlled within the aforementioned range include, for instance, the concentration of lime slurry used in the carbonation reaction as described later, the temperature employed in the carbon oxidation reaction, the concentration of carbon dioxide used, and the types and combinations of additives used in the carbonation reaction. When these conditions are not sufficiently set, it is sometimes difficult to obtain surface-treated calcium carbonate particles that satisfy the aforementioned Sw range.

[0051] (b) Phosphorus content (Pw) measured using an inductively coupled plasma (ICP) luminescence spectrophotometer.

[0052] In this invention, the surface-treated calcium carbonate particles have a specified phosphorus content (Pw; ppm) as measured using an ICP-based luminescence spectrophotometer. In this invention, the Pw of the surface-treated calcium carbonate particles is 300 ≤ Pw ≤ 5000 (ppm), preferably 400 ≤ Pw ≤ 3500 (ppm), and more preferably 500 ≤ Pw ≤ 2000 (ppm). If Pw is less than 300 (ppm), the particles themselves do not possess sufficient heat resistance. If Pw exceeds 5000 (ppm), it is impossible to improve the heat resistance of the particles to that level; instead, the wastewater from the dehydration process during the production of these surface-treated calcium carbonate particles contains a large amount of phosphorus, forcibly placing an excessive load on the wastewater treatment equipment.

[0053] (Method for determining Pw)

[0054] Pw can be measured using, for example, the SPS3500 ICP luminescence spectrophotometer manufactured by Esaiai Nanotekinoroge Co., Ltd., and by operating as follows.

[0055] (1) First, put 1.0g of surface-treated calcium carbonate filler for testing into the crucible and calcine it at 300°C for 3 hours in an electric furnace.

[0056] (2) After calcination, add about 60 mL of distilled water and 7.5 mL of 1.38 equivalent nitric acid (nitric acid (1.38) for the determination of harmful metals, manufactured by Fujifilm and Kojun Pharmaceutical Co., Ltd.) to a beaker, boil the mixture in an electric furnace, and then cool it slowly.

[0057] (3) Add the above slowly cooled mixture to a 100 mL volumetric flask containing 100 μg yttrium, and then dilute to 100 mL with distilled water.

[0058] (4) Next, filter the solution with 5C filter paper and use the filtrate to prepare a sample for ICP determination.

[0059] (5) Subsequently, the phosphorus content (ppm) contained in the sample was determined using the above-mentioned ICP luminescence spectrophotometer.

[0060] (c) Calcification rate

[0061] In this invention, the surface-treated calcium carbonate particles meet a specified calcification rate. Here, the term "calcification rate" as used in this specification refers to the percentage of the mass (g) of the fatty acids constituting calcium fatty acids relative to the total surface treatment amount (g) of the surface-treated calcium carbonate particles. In this invention, the calcification rate of the surface-treated calcium carbonate particles is 50 ≤ calcification rate ≤ 95 (mass%), preferably 55 ≤ calcification rate ≤ 85 (mass%), and more preferably 60 ≤ calcification rate ≤ 80 (mass%). If the calcification rate of the surface-treated calcium carbonate particles is less than 50% by mass, surface-treated calcium carbonate particles with the desired heat resistance cannot be obtained, and during mixing and extrusion operations, resin charring may sometimes occur due to the residual surface treatment agent and inorganic filler in the resin and / or resin composition. If the calcification rate of the surface-treated calcium carbonate particles exceeds 95% by mass, the dispersibility in the resin composition may sometimes decrease.

[0062] (Methods for determining calcification rate)

[0063] The calcification rate can be determined by a general extraction method. Specifically, in the surface treatment agent used to obtain surface-treated calcium carbonate particles, calcium fatty acids are insoluble in 95% by mass ethanol, while fatty acids and their alkali metal salts are soluble in 95% by mass ethanol. As a result, by utilizing this difference in solubility, the calcification rate of the surface-treated calcium carbonate particles can be determined as follows.

[0064] (1) First, add 5.0 g of surface-treated calcium carbonate particles and 80 g of 95% by mass ethanol to a 300 mL conical flask.

[0065] (2) Next, the conical flask is immersed in a water bath at 90°C or higher, and the surface treatment agent remaining on the surface-treated calcium carbonate particles is extracted by reflux for 1 hour.

[0066] (3) After cooling to 20°C, use a Teflon (registered trademark) filter with a diameter of less than 0.5 μm to filter the contents of the conical flask.

[0067] (4) Place the obtained filtrate in a dried and quantitative 200 mL beaker, and evaporate it in a water bath at 90°C or above to remove the solvent. Determine the mass of the obtained residue (the mass of the residue is equivalent to the total amount of fatty acids and alkali metal salts of fatty acids in the surface treatment agent remaining in the surface-treated calcium carbonate particles).

[0068] (5) The mass obtained through (4) above is the mass of fatty acids and alkali metal salts of fatty acids in the surface treatment agent per 5.0g of surface-treated calcium carbonate particles. Therefore, by multiplying this value by 1 / 5, the content of fatty acids and alkali metal salts of fatty acids in the surface treatment agent per 1.0g of surface-treated calcium carbonate particles is calculated in the form of mass % (X). It should be noted that (X) is a numerical value including alkali metal elements obtained from alkali metal salts of fatty acids, etc. Therefore, in order to calculate the mass % of fatty acids obtained from fatty acids and alkali metal salts of fatty acids, the content of alkali metal elements contained in the surface-treated calcium carbonate particles (mass %; Y) is subtracted by atomic absorption spectrometry.

[0069] (6) Based on X (mass%) and Y (mass%) and the thermal weight loss TG (mass%) per 1g of calcium carbonate at 200℃~500℃, the percentage of the mass (g) of the fatty acids constituting the calcium carbonate relative to the total surface treatment amount (g) of the surface-treated calcium carbonate particles (i.e., calcification rate) is calculated using the following formula:

[0070] Calcification rate (mass%) = {(Tg(mass%) - (X(mass%) - Y(mass%))} / TG(mass%) × 100

[0071] Here, the content (mass %) of alkali metal elements contained in the above-mentioned surface-treated calcium carbonate particles is determined by the following procedure.

[0072] (A method for determining alkali metals based on atomic absorption spectrometry)

[0073] 1.0 g of surface-treated calcium carbonate granules was weighed into a crucible and placed in a muffle furnace (Masuda Rika Kogyo Co., Ltd. NMF-120). After calcination at 300°C for 2 hours, the calcined granules were cooled to room temperature in a desiccator. The sample was then added to a 200 mL beaker, followed by 60 mL of distilled water. Next, 7.5 mL of 1.38 equivalent nitric acid (nitric acid (1.38) for the determination of harmful metals, manufactured by Fujifilm and Kojun Pharmaceutical Co., Ltd.) was added. The beaker was then capped and boiled using an electric heater. After cooling to room temperature, the mixture was transferred to a 100 mL volumetric flask and diluted to 100 mL with distilled water to prepare the test sample. The content (mass %; Y) of the alkali metal element was determined using an atomic absorption spectrophotometer (Shimadzu Corporation AA-6700F).

[0074] In addition, the thermal weight loss (TG) per 1g of calcium carbonate at 200℃~500℃ used to calculate the above-mentioned calcification rate was determined as follows.

[0075] (Methods for determining TG)

[0076] Approximately 30 mg of surface-treated calcium carbonate particles were weighed into a platinum sample pan. The thermogravimetric analysis (TGA) of these particles, performed by heating from 200 °C to 500 °C at a rate of 30 °C / min, was conducted using, for example, a differential thermal analysis apparatus (DTG-60A, manufactured by Shimadzu Corporation). The TGA (TG, mass%) of each gram of surface-treated calcium carbonate was then determined.

[0077] The calcification rate can be adjusted by controlling the temperature history in the surface treatment and drying processes during the manufacture of the surface-treated calcium carbonate particles constituting the filler of the present invention. This temperature history can be exemplified by, for example, the temperature used in the surface treatment and drying processes and the time of exposure to that temperature. Specific examples of the temperature history include: the temperature of the calcium carbonate aqueous slurry used when surface-treating synthetic calcium carbonate obtained by wet carbonation or similar methods with surface treatment agents (fatty acids and phosphoric acids) and the time required for surface treatment; the temperature at which the surface treatment agent combines with calcium carbonate (surface treatment) and the time required for surface treatment; the temperature required for dehydration after surface treatment and the dehydration time; the time required for the subsequent drying process and the drying time; and combinations thereof. For example, if a thermally conductive dryer is selected when manufacturing surface-treated calcium carbonate particles, drying requires a longer time compared to an instant dryer such as a spray dryer. In cases where the calcification rate is insufficient during surface treatment, the drying temperature and drying time can sometimes be adjusted to increase the calcification rate. In cases where the calcification rate is insufficient during surface treatment and the drying time cannot be maintained sufficiently, it is sometimes difficult to obtain surface-treated calcium carbonate particles that meet the aforementioned calcification rate range.

[0078] Furthermore, the surface-treated calcium carbonate particles contained in the surface-treated calcium carbonate filler of the present invention preferably satisfy one or more of the following (d), (e) and (f) in addition to satisfying (a) to (c) above, and more preferably satisfying all of (d), (e) and (f).

[0079] (d) The 50% diameter (D50) accumulated from the smaller particle side in the volumetric particle size distribution.

[0080] In this invention, the surface-treated calcium carbonate particles preferably have a 50% diameter (D50; μm) accumulated from the small particle side in the volumetric particle size distribution measured using a laser diffraction particle size distribution measuring device, which meets the specified range. In this invention, the D50 of the surface-treated calcium carbonate particles is preferably 0.1 ≤ D50 ≤ 1.5 (μm), more preferably 0.2 ≤ D50 ≤ 1.2 (μm), and even more preferably 0.3 ≤ D50 ≤ 0.8 (μm). While it is technically possible to obtain surface-treated calcium carbonate particles with a D50 less than 0.1 (μm), this requires more advanced and precise technology, potentially increasing manufacturing costs. If the D50 exceeds 1.5 μm, filter clogging can sometimes occur.

[0081] (Method for determining D50)

[0082] D50 can be measured using, for example, a laser diffraction particle size distribution measuring device (MT-3300EXII manufactured by Microtrack Bell), and together with D10, D90 and Da described later, by the following operation.

[0083] (1) First, add 0.3g of the sample of surface-treated calcium carbonate particles and 50mL of medium to a 100mL beaker.

[0084] (2) Next, the contents of the beaker are dispersed by irradiating the contents with ultrasonic waves at 300μA for 60 seconds using, for example, an ultrasonic disperser US-300T manufactured by Nippon Seiki Co., Ltd.

[0085] (3) Subsequently, the volumetric particle size distribution of the surface-treated calcium carbonate particles in the sample was determined using a laser diffraction particle size distribution measuring device (MT-3300EX II manufactured by Microtrace Bell).

[0086] It should be noted that methanol and ethanol, as well as combinations thereof, can be used as media in the above determinations.

[0087] D50 can be controlled by changing various conditions during the manufacture of the surface-treated calcium carbonate particles constituting the filler of the present invention. Various methods have been used to disperse calcium carbonate particles, including methods that reduce D50 by finely crushing the particles using mechanical methods such as ball mills, sand mills, impact mills, homogenizers, and DYNO-MILLs. However, in the carbon dioxide reaction method of wet synthesis, Ostwald ripening, which grows the calcium carbonate particles to a predetermined size and disperses them, is preferred as a method for controlling the particle size.

[0088] (e) Sharpness index of volumetric particle size distribution ((D90-D10) / D50)

[0089] In this invention, the surface-treated calcium carbonate particles preferably have a sharpness index ((D90-D10) / D50) in their volumetric particle size distribution, measured using a laser diffraction particle size distribution measuring device, that meets a specified range. Here, D50 is as described above, D90 is the 90% diameter (μm) accumulated from the small particle side in the volumetric particle size distribution measured using the laser diffraction particle size distribution measuring device, D10 is the 10% diameter (μm) accumulated from the small particle side in the volumetric particle size distribution measured using the laser diffraction particle size distribution measuring device, and Da is the maximum particle size (μm) in the volumetric particle size distribution measured using the laser diffraction particle size distribution measuring device. In this invention, the sharpness index ((D90-D10) / D50) of the surface-treated calcium carbonate particles is preferably 0.9 ≤ (D90-D10) / D50 ≤ 2.0, more preferably 1.0 ≤ (D90-D10) / D50 ≤ 1.6. While it is technically possible to obtain surface-treated calcium carbonate particles with an acuity index of less than 0.9, this requires more advanced and precise techniques, which may increase manufacturing costs. If the acuity index of the surface-treated calcium carbonate particles exceeds 2.0, the dimensional deviation of the voids formed in the molded product (e.g., film) obtained by mixing the resulting surface-treated calcium carbonate filler with resin may become larger, making it difficult to obtain a porous film with a uniform in-plane void distribution.

[0090] (Method for determining the sharpness index ((D90-D10) / D50))

[0091] The sharpness indices D10, D90, and Da can be measured using, for example, a laser diffraction particle size distribution measuring device (MT-3300EX II manufactured by Microtrack Bell Co., Ltd.) described for measuring the aforementioned D50, and the same operation as the measurement of the aforementioned D50 can be performed.

[0092] The sharpness index can be controlled by changing various conditions during the manufacturing of the surface-treated calcium carbonate particles constituting the filler of the present invention. Methods to reduce the sharpness index of calcium carbonate particles (e.g., reducing coarse and fine particles to concentrate the particle size distribution) can also be achieved by using mechanical methods such as ball mills, sand mills, impact mills, homogenizers, and DYNO-MILLs, or by a method called elutriation that separates fine and coarse particles by utilizing the difference in settling velocity in water due to particle size. From the viewpoint that the sharpness index is easily reduced due to the increased uniformity of calcium carbonate particle size, Ostwald curing is preferred.

[0093] (f) Maximum particle size (Da) in the volumetric particle size distribution

[0094] In the present invention, the surface-treated calcium carbonate particles preferably satisfy the following in the volume particle size distribution measured by a laser diffraction particle size distribution measuring device: the maximum particle size (Da) is within a specified range. In the present invention, Da of the surface-treated calcium carbonate particles is preferably Da ≤ 5.0 (μm) (i.e., 0 < Da ≤ 5.0 (μm)), more preferably Da ≤ 4.0 (μm) (i.e., 0 < Da ≤ 4.0 (μm)). If Da exceeds 5.0 μm, for example, when the obtained surface-treated calcium carbonate filler is kneaded with a resin, the dispersion may become insufficient, and clogging of the filter screen may easily occur.

[0095] (Method for measuring Da)

[0096] Da can be measured using, for example, the laser diffraction particle size distribution measuring device (MT-3300EX II manufactured by Microtrac Bell Corporation) described for measuring D50 above, and operating in the same manner as the measurement of D50 above.

[0097] Da can be controlled by changing various conditions when manufacturing the surface-treated calcium carbonate particles constituting the filler of the present invention. As a method for reducing the maximum particle size (Da) in the volume particle size distribution, it is preferable to perform classification using gravity, centrifugal force, buoyancy beneficiation, etc. such as clarification for the purpose of removing impurities and coarse particles at the time of the water slurry form, and removal using a sieve / filter, etc., or to perform classification operations such as air classification at the time of the powder form separately to remove aggregates generated by drying.

[0098] (Surface-treated calcium carbonate particles surface-treated with a surface treatment agent)

[0099] As described above, the surface-treated calcium carbonate particles contained in the surface-treated calcium carbonate filler of the present invention satisfy all of the formulas (a), (b), and (c), and optionally satisfy (d), (e), and (f). Such surface-treated calcium carbonate particles are surface-treated with a surface treatment agent. It should be noted that the term "surface-treated" used in this specification is used to represent the "state" of the surface of the surface-treated calcium carbonate particles. On the other hand, the terms "perform surface treatment / have been surface-treated" used in this specification are used to represent the meaning that the surface of the calcium carbonate particles before surface treatment (i.e., before surface treatment) has undergone a process of being modified (surface treatment), and are clearly distinguished from the above "surface-treated".

[0100] The surface-treated calcium carbonate particles in the present invention are particles obtained by surface-treating unmodified (before surface treatment) calcium carbonate particles with a surface treatment agent.

[0101] Here, from the viewpoint of degassing during resin mixing, unmodified calcium carbonate particles are synthetic calcium carbonate particles (e.g., light / colloidal calcium carbonate) that allow for more uniform particle control, compared to natural products (heavy calcium carbonate) containing a large amount of fine powder particles. From the viewpoint of crystal stability, calcite is preferred as the main component of the crystal morphology, and colloidal calcium carbonate is preferred from the viewpoint of fewer microparticles and coarse particles, and relatively maintaining particle uniformity.

[0102] In addition, to further improve the uniformity of the synthesized calcium carbonate particles, the calcium carbonate particles can be obtained by the following operation: using a separation device such as a liquid hydrocyclone to separate the light liquid (particle side) and the heavy liquid in an appropriate ratio from the water slurry used to obtain the synthesized calcium carbonate particles or the water slurry containing calcium hydroxide before manufacturing the synthesized calcium carbonate particles.

[0103] The above-mentioned surface treatment agent contains fatty acids and phosphoric acid as its main components.

[0104] The fatty acids contained in the above-mentioned surface treatment agent have the ability to modify the surface of the calcium carbonate particles by forming calcium fatty acid on at least a portion, preferably all, of the surface of the unmodified calcium carbonate particles through a substitution reaction.

[0105] Fatty acids can be categorized into fatty acids and fatty acid salts, as well as combinations thereof.

[0106] Examples of fatty acids include saturated fatty acids, unsaturated fatty acids, alicyclic carboxylic acids, and combinations thereof.

[0107] Examples of saturated fatty acids include decanoic acid, lauric acid, myristic acid, palmitic acid, and stearic acid, as well as combinations thereof. Examples of unsaturated fatty acids include oleic acid, linoleic acid, and linolenic acid, as well as combinations thereof. Examples of alicyclic carboxylic acids include cycloalkanoic acids with carboxyl groups at the ends of cyclopentane and cyclohexane rings.

[0108] Fatty acid salts can be listed as alkali metal salts (e.g., sodium salts, potassium salts), alkaline earth metal salts (e.g., calcium salts, magnesium salts), ammonium salts, and amine salts, as well as combinations thereof. Based on their high solubility in water and ease of treating calcium carbonate surfaces, alkali metal salts of fatty acids are the preferred choice.

[0109] Examples of fatty acid salts include saturated fatty acid salts such as potassium laurate, potassium myristate, potassium palmitate, sodium palmitate, potassium stearate, and sodium stearate; unsaturated fatty acid salts such as potassium oleate and sodium oleate; alicyclic carboxylate salts such as lead naphthenate and lead cyclohexylbutyrate; and combinations thereof.

[0110] The aforementioned fatty acids can be, for example, modified or unmodified fatty acids derived from animals or plants. They can be, for example, mixed fatty acids commonly used in this technical field, such as tallow fatty acids, palm oil fatty acids, palm kernel oil fatty acids, soybean oil fatty acids, etc.; their alkali metal salts; or so-called hydrogenated mixed fatty acids or their alkali metal salts that have been hydrogenated to reduce the unsaturation of these mixed fatty acids.

[0111] It should be noted that, when using fatty acids directly as fatty acids, for the purpose of achieving a more uniform surface treatment of the unmodified calcium carbonate particles, it is preferable to dissolve them in hot water heated to above the melting point of the fatty acid used, add an appropriate amount of known emulsifiers such as anionic surfactants and nonionic surfactants, emulsify the fatty acids using a homogenizer or homogenizer, and then add them to the unmodified calcium carbonate.

[0112] Furthermore, among the aforementioned fatty acids, unsaturated fatty acids not only have high solubility in water but also low melting points. Therefore, they facilitate more uniform surface treatment of unmodified calcium carbonate particles. On the other hand, from a heat resistance perspective, unsaturated fatty acids are prone to thermal degradation due to the presence of unsaturated double bonds. Therefore, in this invention, to preemptively eliminate the risk of thermal degradation associated with unsaturated fatty acids, the fatty acids are preferably saturated fatty acids and / or saturated fatty acid salts. Alternatively, the total amount of saturated fatty acids and saturated fatty acid salts is preferably 90% by mass or more, more preferably 100% by mass, relative to the total mass of the fatty acids.

[0113] It should be noted that the proportion of fatty acids present in the surface-treated calcium carbonate filler of the present invention can be easily determined by gas chromatography, for example, as follows.

[0114] (1) First, weigh 1.0 mg of the sample containing surface-treated calcium carbonate particles as a surface-treated calcium carbonate filler and 10 μ mL of tetramethylammonium hydroxide (10% by mass methanol solution) as an esterification agent and place them in the sample cell. Then, use a thermal decomposition device (e.g., a multi-functional pyrolyzer MODEL EGA / PY-3030D manufactured by Frontier Labs) to perform thermal decomposition at 300°C for 30 seconds to vaporize the sample.

[0115] (2) Next, the composition of fatty acids in the vaporized components can be analyzed using a gas chromatography-mass spectrometry (GCMS-QP2010Ultra manufactured by Shimadzu Corporation) under the following conditions:

[0116] (Conditions for gas chromatography)

[0117] Vaporization chamber temperature: 250℃

[0118] Column used: RTX-5MS column (30m length, 0.25μm membrane pressure, 0.25mm inner diameter D)

[0119] Column conditions: heating rate of 10℃ / min, 40~300℃, holding time at 300℃ for 10 minutes.

[0120] Carrier gas: He

[0121] Pressure: 80 kPa

[0122] Total flow rate: 76.5 mL / min

[0123] Column flow rate: 1.5 mL / min

[0124] Split ratio: 46.

[0125] (Conditions for mass spectrometry analysis)

[0126] Ion source temperature: 230℃

[0127] Interface temperature: 250℃

[0128] Solvent elution time: 1.5 minutes.

[0129] Phosphoric acids that may be contained in the aforementioned surface treatment agents include, for example, inorganic phosphoric acids, organic phosphoric acids, and combinations thereof.

[0130] Examples of inorganic phosphoric acids include phosphorous acid, phosphonic acid, orthophosphoric acid, pyrophosphoric acid, polyphosphoric acid, and condensed phosphoric acid, their salts (e.g., alkali metal salts such as sodium and potassium salts; alkaline earth metal salts such as magnesium salts; aluminum salts), and combinations thereof. Examples of organic phosphoric acids include phosphonic acids, phosphate esters, acid phosphate esters, their salts (e.g., alkali metal salts such as sodium and potassium salts; alkaline earth metal salts such as magnesium salts; aluminum salts), and combinations thereof.

[0131] In this invention, phosphates are preferably compounds that have the ability to chelate calcium ions.

[0132] Generally, if an appropriate amount of alkali metal salts, such as fatty acids, is dissolved in an aqueous slurry of calcium carbonate particles as a surface treatment agent, some of it will react with the calcium ions that have already been eluted from the calcium carbonate particles into the aqueous slurry, forming free calcium salts of fatty acids. These free calcium salts of fatty acids do not contribute to the surface treatment of the calcium carbonate particles; therefore, the surface treatment of calcium carbonate becomes insufficient.

[0133] In contrast, if a chelating compound, such as a phosphate, is added to the aqueous slurry, it can preferentially capture calcium ions and inhibit the formation of calcium salts of the aforementioned free fatty acids. As a result, most of the alkali metal salts of the fatty acids contribute to the surface treatment of the calcium carbonate particles, and improved heat resistance of the surface-treated calcium carbonate particles can be expected even with suppressed addition of alkali metal salts of fatty acids. Furthermore, since the surface treatment of calcium carbonate particles can be more uniform, improved dispersibility of the resulting surface-treated calcium carbonate particles is expected.

[0134] In addition, as mentioned above, the formation of calcium salts of fatty acids is hindered due to the capture of calcium ions. As a result, the proportion of fatty acids with poor heat resistance and alkali metal salts of fatty acids that remain increases, that is, the calcification rate decreases. By applying sufficient heat or time during surface treatment or drying to increase the already reduced calcification rate, the proportion of calcium fatty acids with excellent heat resistance can be further increased.

[0135] Examples of phosphates with chelating ability include inorganic condensed phosphates and acid phosphates such as sodium hexametaphosphate, sodium polyphosphate, sodium pyrophosphate, and sodium ultraphosphate, as well as combinations thereof.

[0136] Here, the chelating ability of phosphates can be expressed using the chelation value (CV) based on the Dow Chem. method. In this invention, the chelation value of phosphates is preferably ≤ 50 mg CaCO3 / g, more preferably ≤ 100 mg CaCO3 / g ≤ 500 mg CaCO3 / g. If the chelation value of phosphates is lower than 50 mg CaCO3, it is sometimes difficult to uniformly surface treat unmodified calcium carbonate particles. If the chelation value of phosphates exceeds 500 mg CaCO3 / g, only a small amount is needed for capping the calcium ions constituting the unmodified calcium carbonate particles; on the other hand, sometimes the phosphorus content in the surface-treated calcium carbonate particles related to the above-mentioned Pw becomes insufficient, making it difficult to obtain the desired heat resistance.

[0137] In this invention, the surface treatment agent may contain other surface treatment agents without impairing the effectiveness of the resulting surface-treated calcium carbonate particles. Examples of other surface treatment agents include aromatic sulfonic acids and their salts or esters, resin acids and their salts or esters; as well as alcohol surfactants, sorbitol fatty acid esters, amide surfactants, amine surfactants, polyoxyalkylene alkyl ethers, polyoxyethylene nonylphenyl ethers, sodium α-olefin sulfonate, long-chain alkyl amino acids, amine oxides, alkylamines, quaternary ammonium salts, and other surfactants; and combinations thereof.

[0138] (Surface treatment of unmodified calcium carbonate particles)

[0139] Surface treatment of unmodified calcium carbonate particles using the above-mentioned surface treatment agent is performed as follows.

[0140] Fatty acids and phosphoric acids, as surface treatment agents, and other surface treatment agents as needed, are added to an aqueous slurry containing unmodified calcium carbonate particles. This method is commonly referred to as wet treatment and is preferred from the viewpoint of appropriately balancing the degree of surface treatment for the calcium carbonate particles and manufacturing efficiency.

[0141] The amount of fatty acids used can vary depending on the BET specific surface area of ​​the so-called unmodified calcium carbonate particles before surface treatment. For example, it is preferable that the larger the BET specific surface area of ​​the unmodified calcium carbonate particles, the greater the amount of fatty acids used. The amount of fatty acids used relative to 100 parts by mass of unmodified calcium carbonate particles is preferably 0.1 parts by mass or more and 10 parts by mass or less. If the amount of fatty acids is less than 0.1 parts by mass, it may be difficult to disperse the fatty acids more uniformly relative to the unmodified calcium carbonate particles. If the amount of fatty acids exceeds 10 parts by mass, it may sometimes seep into the surface of the molded article obtained by mixing the obtained surface-treated calcium carbonate filler with the resin composition, resulting in a decrease in the strength of the molded article, and on this basis, the aforementioned calcification rate may be difficult to exceed 50% by mass.

[0142] The amount of phosphates used varies depending on the BET specific surface area and / or amount of unmodified calcium carbonate particles, the phosphorus content of the phosphates themselves, the type of resin to be finally mixed, and the mixing conditions. Therefore, there are no particular limitations, and those skilled in the art can appropriately select the amount of phosphates in a manner that satisfies the above-mentioned Pw range.

[0143] There is no particular limitation on the order in which unmodified calcium carbonate particles are treated with the aforementioned fatty acids and phosphoric acids. For example, unmodified calcium carbonate particles can be treated with fatty acids first, followed by treatment with phosphoric acid. Alternatively, unmodified calcium carbonate particles can be treated with phosphoric acid first, followed by treatment with fatty acids. Or, unmodified calcium carbonate particles can be treated with fatty acids and phosphoric acid together, i.e., simultaneously.

[0144] In this invention, for the reason that the surface state of the obtained surface-treated calcium carbonate particles is more uniform and that it can impart excellent dispersibility, it is preferable to treat the unmodified calcium carbonate particles by simultaneously adding fatty acids and phosphoric acid. Alternatively, for the reason that capturing calcium ions in the aqueous slurry can make the surface-treated calcium carbonate particles more uniform and impart excellent dispersibility, it is most preferable to treat them with phosphoric acid first, and then treat them with fatty acids.

[0145] Regarding the surface treatment temperature in the aqueous slurry, it is preferable to perform the surface treatment at a temperature above the melting point of the fatty acids used as the surface treatment agent. If the surface treatment temperature is below the melting point of the fatty acids, the surface treatment of the calcium carbonate particles may become uneven, and the calcification rate may be excessively reduced. On the other hand, by setting the surface treatment temperature above the melting point of the fatty acids, not only is the uniformity of the surface treatment and the calcification rate increased, but the surface treatment can also be performed in a shorter time.

[0146] In one embodiment, the surface treatment temperature is preferably 0°C to 70°C, more preferably 10°C to 60°C, and even more preferably 20°C to 50°C, relative to the melting point temperature of the fatty acids used.

[0147] In one embodiment, the surface treatment temperature is preferably 20°C to 98°C, more preferably 40°C to 90°C, and even more preferably 60°C to 80°C.

[0148] After the above surface treatment, the resulting particles can be processed into powder by any operation such as dehydration, drying, and pulverization, for example, using conventional methods.

[0149] It should be noted that, in this invention, even if the surface treatment is insufficient in heat and / or time, by using a heat-conducting dryer or similar dryer that can adequately impart heat when drying the dehydrated filter cake obtained by dehydrating the slurry containing surface-treated calcium carbonate particles, it is possible to improve the uniformity of the surface treatment of the obtained surface-treated calcium carbonate particles and increase the calcification rate.

[0150] This operation yields surface-treated calcium carbonate particles containing surface-treated fatty acids and phosphoric acid, satisfying all of equations (a), (b), and (c), and, as needed, (d), (e), and (f) of the surface-treated calcium carbonate filler.

[0151] 2. Resin composition

[0152] Next, the resin composition of the present invention will be described.

[0153] The resin composition of the present invention contains a resin and the above-mentioned surface-treated calcium carbonate filler.

[0154] The resin included in the resin composition is not particularly limited, and examples include, for instance, polyolefin resins, polystyrene resins, acrylic resins, methacrylic resins, vinyl chloride resins, vinylidene chloride resins, polyamide resins, polyether resins, vinyl acetate resins, and polyvinyl alcohol resins, as well as combinations thereof. Specific examples of polyolefin resins include low-density polyethylene (LDPE), high-density polyethylene (HDPE), linear low-density polyethylene (L-LDPE), ultra-high molecular weight polyethylene (UHMWPE), and other polyethylene resins; polypropylene resins; ethylene-propylene copolymers; copolymers of ethylene or propylene with other monomers, etc. The resin can be of petroleum origin, plant origin (e.g., bioplastics), or combinations thereof. In this invention, the resin is preferably a polyolefin resin because it has a lower molding temperature compared to engineering plastics, and because the surface-treated calcium carbonate particles described above have sufficient heat resistance to withstand temperatures at which heat resistance can be achieved.

[0155] The content of surface-treated calcium carbonate filler in the resin composition varies depending on the type of resin used, the intended use of the resulting resin composition, and the desired physical properties, and is therefore not necessarily limited. For example, it is 0.05 to 100 parts by weight relative to 100 parts by weight of resin, preferably 50 to 100 parts by weight, and more preferably 70 to 100 parts by weight. If the content of surface-treated calcium carbonate filler in the resin composition exceeds 100 parts by weight (i.e., if it exceeds the resin content), the compatibility with the resin may sometimes decrease, and the color (whiteness) may decrease due to resin deterioration. If the content of surface-treated calcium carbonate filler in the resin composition is less than 0.05 parts by weight, the resulting resin composition may sometimes lack sufficient heat resistance.

[0156] It should be noted that the resin composition of the present invention may contain, as other additives, lubricants such as fatty acids, fatty acid amides, vinyl bis-stearamide, and dehydrated sorbitol fatty acid esters; plasticizers; stabilizers such as heat stabilizers and light stabilizers; antioxidants; ultraviolet absorbers; neutralizers; antifogging agents; antiblocking agents; antistatic agents; lubricants; and colorants; and combinations thereof. The content of other additives is not particularly limited, and those skilled in the art can select appropriate amounts within a range that does not impair the effects achieved by the surface-treated calcium carbonate filler described above.

[0157] The resin and surface-treated calcium carbonate filler, as well as other additives included as needed, can be mixed under heating using means known in the art, such as single-screw or twin-screw extruders, kneaders, or Banbury mixers.

[0158] Thus, the resin composition of the present invention can be obtained.

[0159] The resin composition can be processed into granules, for example, as a masterbatch. Alternatively, it can be used directly in a compounded state to obtain the molded articles described later.

[0160] 3. Molded products

[0161] The molded article of the present invention is composed of the above-described resin composition.

[0162] For example, the resin composition, after being compounded as described above, can be formed into a sheet using a T-die or similar device, and then stretched uniaxially or biaxially to obtain a porous membrane with micropores on its surface. Alternatively, by forming a film using a known molding machine such as a T-die extrusion or blow molding after the above compounding, and then subjecting it to acid treatment to dissolve the aforementioned surface-treated calcium carbonate filler, a porous membrane with micropores on its surface can also be obtained. Furthermore, multiple T-die extruders in the above process can be overlapped or laminated after stretching to form a multilayer film as needed. In addition, to impart printability to the film, surface treatments such as plasma discharge can be applied to the film surface, and an ink-receiving layer can be coated.

[0163] Thus, the molded articles of the present invention preferably have a film morphology.

[0164] Example

[0165] The present invention will be described in detail below with examples, but the present invention is not limited to these examples. It should be noted that, unless otherwise specified, % refers to mass, and parts refers to parts by mass.

[0166] The following procedures were performed to evaluate the materials, surface-treated calcium carbonate fillers, and granules described in the various embodiments and comparative examples.

[0167] (BET specific surface area of ​​unmodified calcium carbonate)

[0168] 0.2–0.3 g of unmodified calcium carbonate particles used in the various examples and comparative examples were placed in the measuring apparatus (Macsorb HMmo del-1201 manufactured by Macsorb Corporation) as a pretreatment. After heating at 200°C for 10 minutes in a mixed nitrogen and helium atmosphere, low-temperature, low-humidity physical adsorption was performed in a liquid nitrogen environment. The BET specific surface area (m²) of the unmodified calcium carbonate particles was then measured. 2 / g).

[0169] (1) BET specific surface area (Sw) of surface-treated calcium carbonate filler

[0170] 0.2–0.3 g of the surface-treated calcium carbonate filler obtained in each example and comparative example was placed in a measuring apparatus (Macsorb HMmodel-1201 manufactured by Macsorb Corporation). As a pretreatment, the filler was heated at 200°C for 10 minutes in a mixed atmosphere of nitrogen and helium, followed by low-temperature and low-humidity physical adsorption in a liquid nitrogen environment. The BET specific surface area (m²) of the surface-treated calcium carbonate particles constituting the filler was then measured. 2 / g).

[0171] (2) The phosphorus content (Pw) of the surface-treated calcium carbonate filler was measured using an inductively coupled plasma (ICP) luminescence spectrophotometer.

[0172] 1.0 g of the surface-treated calcium carbonate filler obtained in the various examples and comparative examples was added to a crucible and calcined at 300°C for 3 hours in an electric furnace. After calcination, approximately 60 mL of distilled water and 7.5 mL of 1.38 equivalent nitric acid (nitric acid (1.38) for the determination of hazardous metals, manufactured by Fujifilm and Koujun Pharmaceutical Co., Ltd.) were added to a beaker containing the mixture, and the mixture was boiled in an electric furnace and then slowly cooled. The slowly cooled mixture was added to a 100 mL volumetric flask containing 100 μg of yttrium, and then diluted to 100 mL with distilled water. The mixture was then filtered through 5°C filter paper, and the resulting filtrate was used to prepare a sample for ICP determination. Subsequently, using the sample, the phosphorus content (ppm) was determined by an inductively coupled plasma (ICP) luminescence spectrophotometer (ICP luminescence spectrophotometer SPS3500 manufactured by Esaiai Nanotech Co., Ltd.).

[0173] (3) Calcification rate of surface-treated calcium carbonate filler

[0174] Add 5.0 g of the surface-treated calcium carbonate filler obtained in the various examples and comparative examples and 80 g of 95% by volume ethanol to a 300 mL Erlenmeyer flask. Then, immerse the Erlenmeyer flask in a water bath at 90°C or higher and reflux it for 1 hour to extract the residual surface-treated agent from the surface-treated calcium carbonate particles constituting the filler.

[0175] After cooling sufficiently to 20°C, the contents of the conical flask are filtered using a Teflon (registered trademark) filter with a diameter of less than 0.5 μm, thus obtaining a filtrate. This filtrate is then transferred to a pre-dried and quantitatively measured 200 mL beaker and evaporated to dryness in a water bath at a temperature above 90°C to remove the solvent, yielding a residue, the mass of which is determined. Here, this mass is the mass of fatty acids and alkali metal salts of fatty acids in the surface-treatment agent per 5.00 g of the surface-treated calcium carbonate particles. Therefore, by multiplying this value by 1 / 5, the content of fatty acids and alkali metal salts of fatty acids in the surface-treatment agent per 1.0 g of surface-treated calcium carbonate particles is calculated in mass % (X).

[0176] It should be noted that the content (X) is a numerical value containing alkali metals derived from alkali metal salts of fatty acids. Therefore, in order to calculate the mass percentage of fatty acids derived from fatty acids and alkali metal salts of fatty acids, the content (mass %) of alkali metals contained in surface-treated calcium carbonate particles is determined by atomic absorption spectrometry as follows.

[0177] 1.0 g of surface-treated calcium carbonate granules was weighed into a crucible and placed in a muffle furnace (Masuda Rika Kogyo Co., Ltd. NMF-120). After calcination at 300°C for 2 hours, the calcined granules were cooled to room temperature in a desiccator. The sample was then added to a 200 mL beaker, followed by 60 mL of distilled water. Next, 7.5 mL of 1.38 equivalent nitric acid (nitric acid (1.38) for the determination of harmful metals, manufactured by Fujifilm and Kojun Pharmaceutical Co., Ltd.) was added. The beaker was then capped and boiled using an electric heater. After cooling to room temperature, the mixture was transferred to a 100 mL volumetric flask and diluted to 100 mL with distilled water to prepare the test sample. The content (mass %; Y) of the alkali metal element was determined using an atomic absorption spectrophotometer (Shimadzu Corporation AA-6700F).

[0178] Based on the contents X (mass%) and Y (mass%), and the thermal weight loss TG (mass%) of 1g of calcium carbonate at 200℃~500℃, the percentage of the mass (g) of the fatty acids constituting the calcium fatty acid composition relative to the total surface treatment amount (g) of the surface-treated calcium carbonate particles constituting the surface-treated calcium carbonate filler (i.e., calcification rate) is calculated using the following formula:

[0179] Calcification rate (mass%) = {(Tg(mass%) - (X(mass%) - Y(mass%))} / TG(mass%) × 100

[0180] It should be noted that the following procedure was performed to determine the thermal weight loss (TG, mass%) of each 1g of calcium carbonate at 200℃~500℃ used in calculating the above calcification rate.

[0181] Approximately 30 mg of surface-treated calcium carbonate filler obtained in each example and comparative example was weighed into a platinum sample pan. The thermogravimetric analysis of the surface-treated calcium carbonate particles constituting the filler was performed using a differential thermal analysis apparatus (DTG-60A manufactured by Shimadzu Corporation) at a heating rate of 30 °C / min from 200 °C to 500 °C, and the result was expressed as TG (mass%) per 1 g of surface-treated calcium carbonate.

[0182] (4) The D50, sharpness index ((D90-D10) / D50) and Da of the surface-treated calcium carbonate filler

[0183] 0.3 g of the surface-treated calcium carbonate filler obtained in each example and comparative example and 50 mL of methanol were added to a 100 mL beaker. Next, the contents of the beaker were dispersed by irradiation with ultrasound at 300 μA for 60 seconds using, for example, an ultrasonic disperser US-300T manufactured by Nippon Seiki Co., Ltd., to obtain a sample. Subsequently, the volumetric particle size distribution of the surface-treated calcium carbonate particles in the sample was measured using a laser diffraction particle size distribution measuring device (MT-3300EX II manufactured by Microtrace Bell Co., Ltd.). Based on the obtained volumetric particle size distribution results, the values ​​of D50, D10, D90, and Da, as well as the sharpness index ((D90-D10) / D50) calculated using these values, were obtained.

[0184] (5) Thermal oxidation stability of granules

[0185] Using a compression molding machine SFA-37 manufactured by Shinto Metal Industries, Ltd., set to 200°C, test pieces were made from the secondary compounded granules obtained in each example and comparative example using a 5cm×5cm×1mm thick mold.

[0186] For this test piece, according to Japanese Industrial Standard JIS K7368 (Plastics - Polypropylene and propylene copolymers - Determination of thermal oxidative stability in air - Oven method), the test piece was heated in air using a forced-ventilation oven at 140°C to promote degradation. The number of days required from the start of the test until localized cracking, collapse and / or discoloration could be visually observed was recorded, and the evaluation was carried out according to the following criteria.

[0187] ◎: Even after 10 days, there was no significant change.

[0188] ○: The color change was confirmed after 10 days.

[0189] △: After 10 days, discoloration and cracking were confirmed.

[0190] ×: After 5 days, discoloration and cracks were confirmed.

[0191] (6) Evaluation of the heat resistance of the granules

[0192] For the granules obtained in each embodiment and comparative example, each granule was heated in air for 10 days in a forced-ventilation oven at 140°C to promote degradation. For the resulting heat-degraded granules and the granules in their initial state (without heat degradation), the melt flow rate (MFR) value (g / 10 min) at 230°C was measured using a MELT INDE XER F-F01 manufactured by Toyo Seiki Co., Ltd. Furthermore, the rate of change (%) of MFR was calculated based on the results using the following formula.

[0193] [Mathematical Expression 1]

[0194]

[0195] (7) Evaluation of the dispersibility of the aggregate

[0196] The granules obtained in each example and comparative example were mixed and extruded in a twin-shaft mixer (Toyo Seiki Co., Ltd. 2D25W) equipped with a three-piece screen with mesh sizes of 100μm, 60μm and 400μm, at 180°C and a feed rate of 150rpm and 3kg / h. The resin pressure was measured after 60 minutes, and the dispersibility was evaluated according to the following criteria.

[0197] ◎: The resin pressure after 60 minutes of mixing is less than 3 MPa.

[0198] ○: The resin pressure after 60 minutes of mixing is above 3MPa and less than 5MPa.

[0199] △: The resin pressure after 60 minutes of mixing is above 5MPa and less than 8MPa.

[0200] ×: Curling occurs due to filter clogging before 60 minutes of mixing.

[0201] (Example 1-1: Preparation of surface-treated calcium carbonate filler (E1))

[0202] A solution containing 10% by mass of BET with a specific surface area of ​​8.0 m² was prepared. 2A slurry of calcium carbonate was prepared by sedimentation, and the temperature of the slurry was adjusted to 60°C. A phosphoric acid aqueous solution was obtained by dissolving sodium hexametaphosphate (sodium metaphosphate manufactured by Taihei Chemical Industry Co., Ltd. with a chelation value of 125 mg CaCO3 / g) at a concentration of 0.60% by mass relative to the calcium carbonate solids in the aqueous solution. Furthermore, as a fatty acid, a substance obtained by dissolving NonsalSK-1 (100% by mass saturated fatty acid content) manufactured by Nippon Yushu Co., Ltd. with a saturated fatty acid content of 2.20% by mass relative to the calcium carbonate solids in the aqueous solution at a concentration of 10% by mass in hot water at 70°C was added.

[0203] It should be noted that the NonsalSK-1 manufactured by Nippon Oils & Fats Co., Ltd. used above has the following composition (potassium myristate is 3% by mass, potassium palmitate is 27% by mass, potassium stearate is 66% by mass, and others are 4% by mass).

[0204] Next, after stirring at 60°C for 24 hours for surface treatment, the material was dehydrated by pressurizing a filter, dried and crushed using a dryer (Hosokawa Mikron Drymeister DMR-1), thereby obtaining surface-treated calcium carbonate filler (E1). The physical properties of the obtained filler (E1) are shown in Tables 1 and 3.

[0205] (Examples 1-2: Preparation of surface-treated calcium carbonate filler (E2))

[0206] Instead of the phosphoric acid aqueous solution used in Examples 1-1, a phosphoric acid aqueous solution was obtained by dissolving sodium hyperphosphate (manufactured by Taihei Chemical Co., Ltd.; chelation value 406 mg CaCO3 / g) with a mass fraction of 0.40% relative to the calcium carbonate solid content at a concentration of 10%. A CD dryer manufactured by Kurimoto Iron Works Co., Ltd. was used as a thermally conductive dryer, and the solution was dried at a vapor pressure of 0.25 MPa for 2 hours. Otherwise, the procedure was the same as in Examples 1-1 to obtain surface-treated calcium carbonate filler (E2). The physical properties of the obtained filler (E2) are shown in Tables 1 and 3.

[0207] (Examples 1-3: Preparation of surface-treated calcium carbonate filler (E3))

[0208] Instead of the phosphoric acid aqueous solution used in Example 1, a phosphoric acid aqueous solution was obtained by dissolving sodium polyphosphate (sodium tripolyphosphate manufactured by Taihei Chemical Industry Co., Ltd.; chelation value 130 mg CaCO3 / g) with a solid content of 0.25% by mass relative to calcium carbonate at a concentration of 10% by mass. A CD dryer manufactured by Kurimoto Iron Works Co., Ltd. was used as a heat-conducting dryer, and the solution was dried at a steam pressure of 0.25 MPa for 2 hours. Otherwise, the procedure was the same as in Example 1-1 to obtain surface-treated calcium carbonate filler (E3). The physical properties of the obtained filler (E3) are shown in Tables 1 and 3.

[0209] (Examples 1-4: Preparation of surface-treated calcium carbonate filler (E4))

[0210] Instead of the phosphoric acid aqueous solution used in Examples 1-1, a phosphoric acid aqueous solution was obtained by dissolving potassium pyrophosphate (manufactured by Rasa Kogyo Co., Ltd.: chelation value of 50 mg CaCO3 / g) with a solid content of 0.20% by mass relative to calcium carbonate at a concentration of 10% by mass. A CD dryer manufactured by Kurimoto Iron Works Co., Ltd. was used as a heat-conducting dryer, and the solution was dried at a steam pressure of 0.25 MPa for 2 hours. Otherwise, the procedure was the same as in Examples 1-1 to obtain surface-treated calcium carbonate filler (E4). The physical properties of the obtained filler (E4) are shown in Tables 1 and 3.

[0211] (Examples 1-5: Preparation of surface-treated calcium carbonate filler (E5))

[0212] Instead of the phosphoric acid aqueous solution used in Examples 1-1, an aqueous solution of phosphoric acid (manufactured by Rasa Kogyo Co., Ltd., 75% phosphoric acid: chelation value of 0 mg CaCO3 / g) with a purity of 1.50% by mass relative to the calcium carbonate solid content was used at a concentration of 10% by mass. Instead of the fatty acids used in Examples 1-1, a substance obtained by dissolving lauric acid 50 (saturated fatty acid content of 84%) manufactured by Miyoshi Oils Co., Ltd. with a purity of 1.60% by mass relative to the calcium carbonate solid content as a fatty acid in hot water at 70°C and saponifying it with an equivalent amount of sodium hydroxide was used. For surface treatment, the solution was stirred at 60°C for 4 hours, and dried at a vapor pressure of 0.25 MPa for 2 hours using a CD dryer manufactured by Kurimoto Iron Works Co., Ltd. as a heat-conducting dryer. Otherwise, the operation was the same as in Examples 1-1 to obtain surface-treated calcium carbonate filler (E5). The physical properties of the obtained filler (E5) are shown in Tables 1 and 3.

[0213] It should be noted that the lauric acid 50 manufactured by Miyashi Oils Co., Ltd. used above has the following composition (lauric acid 54% by mass, myristic acid 17% by mass, palmitic acid 10% by mass, stearic acid 2% by mass, oleic acid 14% by mass and others 3% by mass).

[0214] (Examples 1-6: Preparation of surface-treated calcium carbonate filler (E6))

[0215] Instead of the phosphoric acid aqueous solution used in Examples 1-1, an aqueous solution of phosphoric acid was obtained by dissolving aluminum dihydrogen phosphate (manufactured by Taihei Chemical Co., Ltd.: chelation value of 0 mg CaCO3 / g) with a solid content of 1.80% by mass relative to calcium carbonate at a concentration of 10% by mass. Instead of the fatty acids used in Examples 1-1, a substance was obtained by dissolving NAAR-122 lauric acid (100% saturated fatty acid content) manufactured by Nippon Yushu Co., Ltd. with a solid content of 1.60% by mass relative to calcium carbonate at a concentration of 10% in hot water at 70°C and saponifying it with an equivalent amount of sodium hydroxide. Furthermore, a CD dryer manufactured by Kurimoto Iron Works Co., Ltd. was used as a heat-conducting dryer, and the material was dried at a steam pressure of 0.25 MPa for 2 hours. Otherwise, the operation was the same as in Examples 1-1 to obtain surface-treated calcium carbonate filler (E6). The physical properties of the obtained filler (E6) are shown in Tables 1 and 3.

[0216] (Examples 1-7: Preparation of surface-treated calcium carbonate filler (E7))

[0217] Instead of the phosphoric acid aqueous solution used in Examples 1-1, an aqueous solution of phosphoric acid was prepared by dissolving 0.30% by mass of nitrosotrimethylenephosphonic acid (PH320 manufactured by Kirest Co., Ltd.: chelation value 200 mg CaCO3 / g) at a concentration of 10% by mass. Instead of the fatty acids used in Examples 1-1, an aqueous solution of lauric acid NAAR-122 manufactured by Nippon Yushu Co., Ltd. (1.60% by mass of calcium carbonate solids, 100% saturated fatty acid content) and an emulsifier (High-Teno NF-08 manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.) at a total concentration of 10% by mass was prepared by dissolving in hot water at 70°C and using a TKROBOMIX (homogenizer M) to achieve a total concentration of 10% by mass. The substance obtained by emulsifying ARKII (manufactured by Special Chemical Industry Co., Ltd.) at 10,000 rpm for 5 minutes was dried at a steam pressure of 0.25 MPa for 2 hours using a CD dryer manufactured by Kurimoto Iron Works Co., Ltd. as a heat-conducting dryer. Otherwise, the operation was the same as in Example 1-1 to obtain surface-treated calcium carbonate filler (E7). The physical properties of the obtained filler (E7) are shown in Tables 1 and 3.

[0218] (Examples 1-8: Preparation of surface-treated calcium carbonate filler (E8))

[0219] A solution containing 10% by mass of BET with a specific surface area of ​​13.0 m² was prepared. 2 A slurry of calcium carbonate was prepared by precipitation, and the temperature of the slurry was adjusted to 60°C. An aqueous solution of phosphoric acid was added, obtained by dissolving sodium hexametaphosphate (sodium metaphosphate manufactured by Taihei Chemical Industry Co., Ltd.: chelation value 125 mg CaCO3 / g) at a concentration of 10% by mass relative to the solid content of calcium carbonate. Furthermore, as a fatty acid, a substance obtained by dissolving NonsalSK-1 (100% saturated fatty acid content) manufactured by Nippon Yushu Co., Ltd. at a concentration of 3.00% relative to the solid content of calcium carbonate in hot water at 70°C was added. Otherwise, the procedure was the same as in Example 1-1 to obtain surface-treated calcium carbonate filler (E8). The physical properties of the obtained filler (E8) are shown in Tables 1 and 3.

[0220] (Examples 1-9: Preparation of surface-treated calcium carbonate filler (E9))

[0221] Instead of the phosphoric acid aqueous solution used in Examples 1-8, a phosphoric acid aqueous solution obtained by dissolving sodium hyperphosphate (manufactured by Taihei Chemical Co., Ltd.: Ultraporin; chelation value 406 mg CaCO3 / g) at a concentration of 10% was used. Instead of the fatty acids used in Examples 1-8, a substance obtained by dissolving NAAR-122 lauric acid (100% saturated fatty acid content) manufactured by Nippon Yushu Co., Ltd. at a concentration of 10% by mass in hot water at 70°C and saponifying with an equivalent amount of sodium hydroxide was used. After stirring at 60°C for 4 hours for surface treatment, the substance was dehydrated under pressure through a filter and dried at a steam pressure of 0.25 MPa for 2 hours using a CD dryer manufactured by Kurimoto Iron Works Co., Ltd. Otherwise, the same procedure as in Examples 1-8 was followed to obtain surface-treated calcium carbonate filler (E9). The physical properties of the obtained filler (E9) are shown in Tables 1 and 3.

[0222] (Examples 1-10: Preparation of surface-treated calcium carbonate filler (E10))

[0223] A solution containing 10% by mass of BET was prepared, with a specific surface area of ​​16.8 m². 2A slurry of calcium carbonate was prepared by precipitation, and the temperature of the slurry was adjusted to 60°C. An aqueous solution of phosphoric acid was added, obtained by dissolving sodium hyperphosphate (Ultrasporin manufactured by Taihei Chemical Co., Ltd.; chelation value 406 mg CaCO3 / g) at a concentration of 1.20% by weight relative to the calcium carbonate solids. Furthermore, as a fatty acid salt, a substance obtained by dissolving NonsalSK-1 (100% saturated fatty acid content) manufactured by Nippon Oils & Fats Co., Ltd. at a concentration of 10% by weight relative to the calcium carbonate solids was added using hot water at 70°C. Otherwise, the procedure was the same as in Examples 1-8 to obtain surface-treated calcium carbonate filler (E10). The physical properties of the obtained filler (E10) are shown in Tables 1 and 3.

[0224] (Examples 1-11: Preparation of surface-treated calcium carbonate filler (E11))

[0225] Instead of the phosphoric acid aqueous solution used in Examples 1-10, a phosphoric acid aqueous solution was prepared by dissolving sodium hexametaphosphate (sodium metaphosphate manufactured by Taihei Chemical Industry Co., Ltd.: chelation value 125 mg CaCO3 / g) at a concentration of 1.20% by mass relative to the calcium carbonate solid content in a 10% solution. The solution was stirred at 80°C for 6 hours for surface treatment, then dehydrated under pressure through a filter, and dried at a steam pressure of 0.25 MPa for 2 hours using a CD dryer manufactured by Kurimoto Iron Works Co., Ltd. Otherwise, the procedure was the same as in Examples 1-10 to obtain surface-treated calcium carbonate filler (E11). The physical properties of the obtained filler (E11) are shown in Tables 1 and 3.

[0226] (Examples 1-12: Preparation of surface-treated calcium carbonate filler (E12))

[0227] Instead of the phosphoric acid aqueous solution used in Examples 1-11, a mixture of fatty acid salt B (saturated fatty acid content of 92%), which was prepared as a fatty acid salt with a solid content of 4.00% by mass relative to calcium carbonate and was prepared with the following composition, was dissolved in hot water at 70°C at a concentration of 10%. The same procedure as in Examples 1-11 was followed, except that a surface-treated calcium carbonate filler (E12) was obtained. The physical properties of the obtained filler (E12) are shown in Tables 2 and 4.

[0228] It should be noted that the mixed fatty acid salt B used above has the following composition (sodium lauryl 10% by mass, sodium myristate 2% by mass, sodium palmitate 20% by mass, potassium stearate 60% by mass and sodium oleate 8% by mass).

[0229] (Comparative Example 1-1: Preparation of Surface-Treated Calcium Carbonate Filler (C1))

[0230] To perform the surface treatment, the mixture was stirred at 80°C for 30 minutes. Otherwise, the same procedure as in Examples 1-12 was followed to obtain the surface-treated calcium carbonate filler (C1). The physical properties of the obtained filler (C1) are shown in Tables 2 and 4.

[0231] (Comparative Examples 1-2: Preparation of Surface-Treated Calcium Carbonate Filler (C2))

[0232] To perform the surface treatment, the mixture was stirred at 60°C for 4 hours. Otherwise, the procedure was the same as in Examples 1-12 to obtain the surface-treated calcium carbonate filler (C2). The physical properties of the obtained filler (C2) are shown in Tables 2 and 4.

[0233] (Comparative Examples 1-3: Preparation of Surface-Treated Calcium Carbonate Filler (C3))

[0234] Instead of the phosphoric acid aqueous solution used in Examples 1-11, a phosphoric acid aqueous solution was obtained by dissolving sodium hexametaphosphate (sodium metaphosphate manufactured by Taihei Chemical Industry Co., Ltd.: chelation value 125 mg CaCO3 / g) at a concentration of 10% by mass, with a relative calcium carbonate solid content of 3.60% by mass. Otherwise, the procedure was the same as in Examples 1-11 to obtain surface-treated calcium carbonate filler (C3). The physical properties of the obtained filler (C3) are shown in Tables 2 and 4.

[0235] (Comparative Examples 1-4: Preparation of Surface-Treated Calcium Carbonate Filler (C4))

[0236] Without adding an aqueous solution of phosphoric acid, the procedure was the same as in Examples 1-11 to obtain surface-treated calcium carbonate filler (C4). The physical properties of the obtained filler (C4) are shown in Tables 2 and 4.

[0237] (Comparative Examples 1-5: Preparation of Surface-Treated Calcium Carbonate Filler (C5))

[0238] Instead of the phosphoric acid aqueous solution used in Examples 1-11, a phosphoric acid aqueous solution was obtained by dissolving 0.30% by weight of nitrosotrimethylenephosphonic acid (PH320 manufactured by Chlorest Co., Ltd.: chelation value of 200 mg CaCO3 / g) relative to the calcium carbonate solid content at a concentration of 10%. Instead of the fatty acids used in Examples 1-11, a solution of 2.00% by weight of stearic acid (CHERRY manufactured by Nippon Oils & Fats Co., Ltd. with a saturated fatty acid content of 100%) relative to the calcium carbonate solid content was used. The emulsifier (High-Teno NF-08 manufactured by Daiichi Kogyo Pharmaceutical Co., Ltd.) with a total concentration of 0.03% by mass was dissolved in hot water at 80°C, and emulsified at 10,000 rpm for 5 minutes using a TKROBOMIX (MARKII homogenizer manufactured by Tokusho Keika Kogyo Co., Ltd.). The resulting material was then stirred at 90°C for 24 hours for surface treatment. Otherwise, the procedure was the same as in Examples 1-11, yielding surface-treated calcium carbonate filler (C5). The physical properties of the obtained filler (C5) are shown in Tables 2 and 4.

[0239] It should be noted that the stearic acid CHERRY manufactured by Nippon Oils & Fats Co., Ltd. used above has the following composition (myristic acid 2% by mass, palmitic acid 31% by mass, stearic acid 66% by mass and others 1% by mass).

[0240] (Examples 1-13: Preparation of surface-treated calcium carbonate filler (E13))

[0241] A solution containing 10% by mass of BET with a specific surface area of ​​20.5 m² was prepared. 2 A slurry of calcium carbonate was prepared by precipitation, and the temperature of the slurry was adjusted to 60°C. An aqueous solution of phosphoric acid was obtained by dissolving sodium hexametaphosphate (sodium metaphosphate manufactured by Taihei Chemical Industry Co., Ltd.: chelation value 125 mg CaCO3 / g) at a concentration of 10% by mass, with a solid content of 3.00% by mass relative to the calcium carbonate solids. Then, as a fatty acid salt, a substance obtained by dissolving NonsalSK-1 (100% saturated fatty acid content) manufactured by Nippon Yushu Co., Ltd. at a concentration of 10% by mass relative to the calcium carbonate solids was added using hot water at 70°C. Next, for surface treatment, the mixture was stirred at 60°C for 24 hours, dehydrated under pressure through a filter, and dried at a steam pressure of 0.25 MPa for 2 hours using a CD dryer manufactured by Kurimoto Iron Works Co., Ltd., and then crushed to obtain surface-treated calcium carbonate filler (E13). The physical properties of the obtained filler (E13) are shown in Tables 2 and 4.

[0242] (Comparative Examples 1-6: Preparation of Surface-Treated Calcium Carbonate Filler (C6))

[0243] While stirring using a Henschel mixer, the BET specific surface area was 2.0 m². 2 A phosphoric acid aqueous solution was prepared by dissolving sodium hexametaphosphate (sodium metaphosphate manufactured by Taihei Chemical Industry Co., Ltd.: chelation value 125 mg CaCO3 / g) at a concentration of 10%, with 0.20% by mass relative to the solid content of calcium carbonate (super #2000 manufactured by Maruo Calcium Co., Ltd.) as a fatty acid. Then, as a fatty acid, 1.00% by mass relative to the solid content of calcium carbonate (CHERRY manufactured by Nippon Yushi Co., Ltd., with a saturated fatty acid content of 100%) was added. Next, the solution was stirred at 110°C for 30 minutes to evaporate the water for surface treatment, thereby obtaining surface-treated calcium carbonate filler (C6). The physical properties of the obtained filler (C6) are shown in Tables 2 and 4.

[0244] (Comparative Examples 1-7: Preparation of Surface-Treated Calcium Carbonate Filler (C7))

[0245] A solution containing 10% by mass of BET with a specific surface area of ​​28.0 m² was prepared. 2 A slurry of calcium carbonate was prepared by sedimentation, and the temperature of the slurry was adjusted to 60°C. An aqueous solution of phosphoric acid was obtained by dissolving sodium hexametaphosphate (sodium metaphosphate manufactured by Taihei Chemical Industry Co., Ltd.: chelation value 125 mg CaCO3 / g) at a concentration of 1.20% by mass relative to the calcium carbonate solids. Then, as a fatty acid salt, a substance obtained by dissolving NonsalSK-1 (100% saturated fatty acid content) manufactured by Nippon Yushu Co., Ltd. at a concentration of 7.00% by mass relative to the calcium carbonate solids in hot water at 70°C was added. For surface treatment, the mixture was stirred at 60°C for 24 hours, then dehydrated under pressure through a filter. Using a CD dryer manufactured by Kurimoto Iron Works Co., Ltd., the mixture was dried at a steam pressure of 0.25 MPa for 2 hours and then crushed to obtain surface-treated calcium carbonate filler (C7). The physical properties of the obtained filler (C7) are shown in Tables 2 and 4.

[0246]

[0247]

[0248]

[0249]

[0250] (Examples 2-1 to 2-13 and Comparative Examples 2-1 to 2-7: Preparation of secondary compounded granules (NE1) to (NE13) and (NC1) to (NC7))

[0251] Ten kilograms of a resin mixture obtained by mixing 30 parts by mass of surface-treated calcium carbonate filler prepared in Examples 1-1 to 1-13 and Comparative Examples 1-1 to 1-7 with 70 parts by mass of polypropylene resin (NOBatek PP FB3B, MFR 7.5, manufactured by Polypro Co., Ltd., Japan) was fed into a twin-screw mixer (2D25W, manufactured by Toyo Seiki Co., Ltd.) equipped with a 100 μm mesh filter. The mixture was extruded at 180°C at a feed rate of 150 rpm and 3 kg / hour, and then cut using a granulator to produce coarse granules. These coarse granules were then dried at 60°C for 24 hours and then kneaded and dried under the same conditions to obtain secondary kneaded granules (NE1) to (NE13) and (NC1) to (NC7), respectively.

[0252] The evaluation results of the obtained secondary compounded granules (NE1) to (NE13) and (NC1) to (NC7) are shown in Tables 5 and 6.

[0253]

[0254]

[0255] As shown in Tables 5 and 6, the secondary compounded granules (NE1) to (NE13) prepared in Examples 2-1 to 2-13 exhibited the same or better thermal oxidative stability compared to the secondary compounded granules (NC1) to (NC7) of Comparative Examples 2-1 to 2-7, and were able to suppress the rate of change caused by the heat resistance test at a lower level. Furthermore, regarding the dispersibility evaluation results, the granules (NE1) to (NE13) of Examples 2-1 to 2-13 were also the same or better than the granules (NC1) to (NC7) of Comparative Examples 2-1 to 2-7.

[0256] Therefore, it can be seen that the surface-treated calcium carbonate filler (E1) to (E13) prepared in Examples 1-1 to 1-13 used in the secondary compounded granules (NE1) to (NE13) of Examples 2-1 to 2-13 has excellent stability and heat resistance compared with the surface-treated calcium carbonate filler (C1) to (C7) prepared in Comparative Examples 2-1 to 2-7 used in the secondary compounded granules (NC1) to (NC7), and has the property of being fully and uniformly dispersed in the resin.

[0257] Industrial utilization

[0258] The present invention is useful in, for example, the fields of resin molding, construction / housing, coatings, and a wide range of related technical fields.

Claims

1. A surface-treated calcium carbonate filler comprising surface-treated calcium carbonate particles treated with fatty acids and phosphoric acid, said surface-treated calcium carbonate filler satisfying the following formulas (a), (b) and (c): (a)3m 2 / g≤Sw≤20m 2 / g (b) 300ppm≤Pw≤5000ppm (c) 50% by mass ≤ calcification rate ≤ 95% by mass Sw represents the BET specific surface area of ​​the surface-treated calcium carbonate particles. Pw represents the phosphorus content in the surface-treated calcium carbonate particles, measured using an inductively coupled plasma optical emission spectrophotometer. The calcification rate is the percentage of the mass of the fatty acids constituting the calcium fatty acid relative to the total surface treatment amount of the calcium carbonate particles in this surface treatment.

2. The surface-treated calcium carbonate filler according to claim 1, further satisfying the following formulas (d), (e) and (f): (d) 0.1μm≤D50≤1.5μm (e) 0.9 ≤ (D90 - D10) / D50 ≤ 2.0 (f) Da≤5.0μm D50 is the 50% diameter accumulated from the small particle side in the volumetric particle size distribution of the surface-treated calcium carbonate particles, as measured using a laser diffraction particle size distribution measuring device. D90 is the 90% diameter accumulated from the small particle side in the volumetric particle size distribution of the surface-treated calcium carbonate particles, as measured using this laser diffraction particle size distribution measuring device. D10 is the 10% diameter accumulated from the small particle side in the volumetric particle size distribution of the surface-treated calcium carbonate particles, as measured using this laser diffraction particle size distribution measuring device. Da represents the maximum particle size in the volumetric particle size distribution of the surface-treated calcium carbonate particles, as measured using the laser diffraction particle size distribution measuring device.

3. The surface-treated calcium carbonate filler according to claim 1, wherein, The fatty acids are at least one compound selected from saturated fatty acids and saturated fatty acid salts.

4. The surface-treated calcium carbonate filler according to claim 1, which is used to form a polyolefin resin composition.

5. A resin composition comprising a resin and any one of claims 1 to 3, a surface-treated calcium carbonate filler.

6. The resin composition according to claim 5, wherein, The resin is a polyolefin resin.

7. A molded article comprising the resin composition of claim 5.

8. The molded article according to claim 7, having a film morphology.

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