阅读说明：本技术 碳酸镁 (Magnesium carbonate ) 是由 中村将志 于 2018-04-25 设计创作，主要内容包括：本发明提供一种新型碳酸镁。碳酸镁的ζ电势设为5mV以上,BET比表面积设为25m<Sup>2</Sup>/g以上。这种碳酸镁能够作为树脂用添加剂等使用。(The invention provides novel magnesium carbonate. The zeta potential of magnesium carbonate is 5mV or more, and the BET specific surface area is 25m 2 More than g. The magnesium carbonate can be used as an additive for resins and the like.)

1. Magnesium carbonate having a zeta potential of 5mV or more and a BET specific surface area of 25m²More than g.

2. The magnesium carbonate according to claim 1, wherein zeta potential is 6 to 25mV and BET specific surface area is 28m²More than g.

3. The magnesium carbonate according to claim 1 or 2, wherein the mercury intrusion is 1-8 cc/g.

4. Magnesium carbonate according to any of claims 1 to 3 wherein the average particle size is 1 to 20 μm.

5. Magnesium carbonate according to any of claims 1-4, wherein the zeta potential7 to 20mV, and a BET specific surface area of 30 to 70m²The mercury intrusion amount is 1.5 to 5cc/g, and the average particle diameter is 2 to 15 μm.

6. Magnesium carbonate according to any of claims 1-5, wherein it is an agglomerate having a paper-house like structure.

Technical Field

The invention relates to novel magnesium carbonate.

Background

Magnesium carbonate is widely used in various industrial fields such as pharmaceuticals, cosmetics, foods, and building materials, and an example of use thereof as a filler has also been reported.

For example, patent document 1 (JP 2005-272752) discloses that the BET specific surface area is 1 to 15m²The anhydrous magnesium carbonate having an average particle diameter of 1 to 10 μm/g can be used as a filler for engineering plastics.

Patent document 1: japanese unexamined patent application publication 2005-272752 (claims, examples)

Disclosure of Invention

The invention aims to provide novel magnesium carbonate.

As shown in patent document 1, magnesium carbonate is known to be used as a filler for engineering plastics and the like.

The present inventors have conducted studies on magnesium carbonate as such a filler, and have found that depending on the type of magnesium carbonate, transparency is impaired and thus the magnesium carbonate cannot be used in applications requiring transparency, or appearance (beauty) is impaired or coloring properties are adversely affected even when transparency is not required.

Under such circumstances, the present inventors have intensively studied and found that specific physical properties of magnesium carbonate are related to transparency when used as a filler, and have further studied and completed the present invention.

That is, the zeta potential of the magnesium carbonate of the present invention is 5mV or more (e.g., 6 to 25 mV). The magnesium carbonate may also have a BET specific surface area of 25m²More than g (e.g., 28 m)²More than g).

The magnesium carbonate of the present invention may have a mercury intrusion of about 1 to 8cc/g and an average particle diameter of about 1 to 20 μm.

Representative magnesium carbonates include: zeta potential of 7-20 mV and BET specific surface area of 30m²A value of at least one of (e.g., 30 to 70 m)²Magnesium carbonate having a mercury intrusion of 1.5 to 5cc/g and an average particle diameter of 2 to 15 μm, and the like.

The magnesium carbonate of the present invention may have a plate shape, and particularly may be an aggregate having a paper-house structure (カ ー ド ハ ウ ス structure) [ shape of aggregate having a paper-house structure (or paper-house shape) ].

The present invention includes the following aspects.

[1]Magnesium carbonate having a zeta potential of 5mV or more and a BET specific surface area of 25m²More than g.

[2]According to [1]The magnesium carbonate has zeta potential of 6-25 mV and BET specific surface area of 28m²More than g.

[3] The magnesium carbonate according to [1] or [2], wherein the mercury intrusion is 1 to 8 cc/g.

[4] The magnesium carbonate according to any one of [1] to [3], wherein the average particle diameter is 1 to 20 μm.

[5]According to [1]～[4]The magnesium carbonate according to any one of the above claims, wherein the zeta potential is 7 to 20mV and the BET specific surface area is 30 to 70m²The mercury intrusion amount is 1.5 to 5cc/g, and the average particle diameter is 2 to 15 μm.

[6] The magnesium carbonate according to any one of [1] to [5], which is an aggregate having a paper-house structure.

[7] Magnesium carbonate for a resin additive, wherein zeta potential is 5mV or more.

[8] The magnesium carbonate according to [7], wherein the resin additive is a filler.

[9]According to [7]Or [8]]The magnesium carbonate has a BET specific surface area of 10m²More than g.

[10] The magnesium carbonate according to any one of [7] to [9], wherein the mercury intrusion is 1 to 8 cc/g.

[11] The magnesium carbonate according to any one of [7] to [10], wherein the average particle diameter is 1 to 20 μm.

[12]According to [7]～[11]The magnesium carbonate according to any one of the above claims, wherein the zeta potential is 6 to 25mV and the BET specific surface area is 15 to 70m²The mercury intrusion amount is 1.5 to 5cc/g, and the average particle diameter is 2 to 15 μm.

[13] The magnesium carbonate according to any one of [7] to [12], which is an aggregate having a paper-house structure.

[14] A composition comprising a resin and the magnesium carbonate according to any one of [1] to [13 ].

[15] The composition according to [14], wherein the resin comprises a vinyl chloride-based resin.

[16] The composition according to [14], wherein the resin comprises a rubber.

[17] The composition according to any one of [14] to [16], wherein the proportion of magnesium carbonate is 0.1 parts by mass or more per 100 parts by mass of the resin.

The invention can provide novel magnesium carbonate.

Such magnesium carbonate can be used for various applications, and is particularly useful as an additive (filler or the like) for resins.

The magnesium carbonate of the present invention can maintain a high level of transparency (or a small decrease in transparency) even when added to a resin, and is easy to satisfy both transparency and a function as a filler, and thus has high usefulness and practicability.

Detailed Description

[ magnesium carbonate ]

The magnesium carbonate of the present invention satisfies specific physical properties and characteristics. In general, the magnesium carbonate of the present invention satisfies a zeta potential in at least a specific range in many cases, and particularly, may satisfy a zeta potential in a specific range and other physical properties in a specific range (for example, at least one selected from the group consisting of a specific surface area, a mercury intrusion amount, and an average particle diameter, particularly, a specific surface area in at least a specific range).

The zeta potential of magnesium carbonate may be selected from the range of, for example, 3mV or more, or may be 5mV or more (for example, 5.5 to 30mV), preferably 6mV or more (for example, 6 to 25mV), more preferably 6.5mV or more (for example, 6.5mV to 22mV), and particularly may be 7mV or more (for example, 7 to 20mV), 7.5mV or more { for example, 8mV or more (for example, 8.3 to 25mV), 8.5mV or more (for example, 8.8 to 20mV), or 9mV or more (for example, 9 to 18 mV).

The upper limit of the zeta potential of magnesium carbonate is not particularly limited, and may be, for example, 30mV, 25mV, 22mV, 20mV, 18mV, 16mV, 15mV, 14mV, 13mV, or the like. The upper limit and the lower limit of the range may be set in an appropriate combination (for example, the same applies to 8 to 18 mV).

By setting the zeta potential range as described above, magnesium carbonate having excellent balance such as transparency is easily obtained. Further, if the zeta potential is too low, the mutual repulsive force of the fine particles is weakened, and the particles are aggregated, whereby the dispersibility in the resin is deteriorated and the transparency is deteriorated. On the other hand, if the zeta potential is too high, there is a possibility that dispersibility in a resin or the like is improved, and on the other hand, physical properties of an added component (such as a resin) are deteriorated due to moisture absorption or the like.

The method of measuring the zeta potential is not particularly limited, and the measurement can be performed by, for example, a method described later.

The BET specific surface area of the magnesium carbonate may be, for example, from 1m²More than g (e.g. 5 m)²More than 10 m/g²Over g), usually from 20m²More than g (e.g., 22 m)²/g or more), and may be 25m²More than g (e.g., 28 m)²More than 29 m/g²/g or more), preferably 30m²More than g (e.g., 32 m)²At least g), more preferably 35m²More than g (e.g., 38 m)²At least g), it can be set to 40m²More than g.

The upper limit of the BET specific surface area of magnesium carbonate is not particularly limited, and may be, for example, 100m²/g、90m²/g、80m²/g、70m²/g、65m²/g、60m²/g、55m²/g、50m²/g、45m²And/g, etc.

By providing such a specific surface area (particularly, in combination with zeta potential, the specific surface area described above), magnesium carbonate advantageous in terms of transparency and strength is easily obtained.

Further, if the specific surface area is too small or too large, the particles themselves are too large, or transparency is impaired by aggregation (re-aggregation) of the particles or the like.

The method for measuring the BET specific surface area is not particularly limited, and can be determined by a one-point method according to JIS8830 (method for measuring the specific surface area of powder (solid) adsorbed by gas), for example.

The mercury intrusion amount of magnesium carbonate may be 0.1cc/g or more, for example, 0.5cc/g or more (for example, 0.8 to 20cc/g), preferably 1cc/g or more (for example, 1.2 to 15cc), more preferably 1.5cc/g or more (for example, 1.6 to 10cc), usually 1 to 8cc/g (for example, 1.2 to 7cc/g, 1.3 to 6cc/g, 1.5 to 5cc/g, etc.), and may be 4cc/g or less (for example, 4cc/g or less, 3.5cc/g or less, 3cc/g or less, 2.5cc or less).

By setting the mercury penetration amount as described above (particularly, in combination with the zeta potential and the specific surface area, the mercury penetration amount described above), it is possible to easily obtain magnesium carbonate which is highly dispersible in a resin or the like and is advantageous in terms of transparency and strength. Further, it is considered that the resin composition has an appropriate volume and is advantageous in terms of handling properties when mixed with a resin or the like.

The method for measuring the mercury intrusion is not particularly limited, and the measurement can be performed by, for example, the method described later.

The magnesium carbonate may be in the form of particles (powder or powder). The shape of the particles is not particularly limited, and may be spherical (substantially spherical), plate-like, or the like. The particles may be primary particles or secondary particles (or aggregates). In particular, the magnesium carbonate particles may be plate-like particles, and more preferably are aggregates of plate-like particles (paper house-like, paper house-like structure, aggregates having a paper house-like structure).

The average particle diameter (or secondary particle diameter) of the particulate magnesium carbonate (magnesium carbonate particles) may be selected from the range of about 100 μm or less (e.g., 70 μm or less), and may be 50 μm or less (e.g., 40 μm or less), preferably 30 μm or less (e.g., 25 μm or less), more preferably 20 μm or less (e.g., 18 μm or less), and may be usually 1 to 20 μm (e.g., 1.5 to 18 μm, 2 to 15 μm, 3 to 12 μm, 3.5 to 10 μm, 4 to 9 μm, 4.5 to 8 μm), or 12 μm or less (e.g., 10 μm or less, 8 μm or less).

By setting the average particle size as described above (particularly, in combination with zeta potential or the like, the above average particle size is set), magnesium carbonate advantageous in transparency and the like is easily obtained.

The method for measuring the average particle diameter is not particularly limited, and the average particle diameter can be measured by, for example, the method described later.

magnesium carbonate of the present invention as long as it contains MgCO₃The amount is not particularly limited, and it may be usually basic magnesium carbonate. Further, the magnesium carbonate (basic magnesium carbonate) may be a hydrate or an hydrate (for example, dihydrate, trihydrate, pentahydrate, or the like).

The basic magnesium carbonate may be a magnetic fluid, and is, for example, a compound represented by the following formula.

nMgCO₃·Mg(OH)₂·mH₂O

In the formula, m and n represent integers (for example, 3 to 8, 4 for m ═ n, 4 for n, 5 for m, and the like). ]

Further, the zeta potential is low when there are many carbonate groups, and the charge tends to be positive when there are many hydroxyl groups.

The apparent specific gravity (apparent specific gravity) of magnesium carbonate may be, for example, about 0.10 to 0.50, preferably about 0.15 to 0.45, and more preferably about 0.20 to 0.40.

Magnesium carbonate as long as it contains MgCO₃(further, Mg (OH))₂、H₂O), then other elements (or compounds) may or may not be present. The other elements are not particularly limited, and include non-metal elements [ e.g., C (carbon), S (sulfur), halogen (e.g., Cl (chlorine)), metal elements or semimetal elements [ e.g., typical metal elements (e.g., alkali or alkaline earth metals such as Na (sodium) and Ca (calcium), elements of group 13 of the periodic table such as B (boron) and Al (aluminum), Si (silicon), etc.), transition metal elements (e.g., Fe (iron), Zn (zinc), etc. ], and the like]And the like. These elements may be contained in magnesium carbonate alone or in combination of two or more.

When the magnesium carbonate contains S, the content (content ratio) of S may be, for example, 0.6% by mass or less (for example, 0.01 to 0.6% by mass), preferably 0.5% by mass or less (for example, 0.01 to 0.3% by mass), and more preferably 0.2% by mass or less (for example, 0.01 to 0.2% by mass).

When the magnesium carbonate contains Na, the Na content (content ratio) may be, for example, 1.0 mass% or less (e.g., 0.01 to 1 mass%), preferably 0.5 mass% or less (e.g., 0.01 to 0.5 mass%), and more preferably 0.3 mass% or less (e.g., 0.01 to 0.3 mass%).

When the magnesium carbonate contains Ca, the content (content ratio) of Ca may be, for example, 1.0 mass% or less (e.g., 0.01 to 1.0 mass%), preferably 0.7 mass% or less (e.g., 0.01 to 0.7 mass%), and more preferably 0.5 mass% or less (e.g., 0.01 to 0.5 mass%).

The method for producing magnesium carbonate is not particularly limited, and for example, it can be produced by blowing carbonic acid gas into magnesium hydroxide slurry or magnesium oxide slurry.

The slurry can be prepared, for example, by dispersing powdered magnesium hydroxide or magnesium oxide in water.

The completion of the reaction (production of magnesium carbonate) can be carried out, for example, by confirming that the reaction solution has a predetermined pH (e.g., about 10 or less). The pH can be confirmed by an indicator (phenolphthalein solution or the like).

The magnesium carbonate formed can be isolated (purified) by a conventional method. For example, after blowing the carbonic acid gas, the slurry after completion of the reaction may be purified by filtration, dehydration, and drying.

The magnesium carbonate obtained may be subjected to a pulverization treatment. The type and degree of the pulverization treatment can be appropriately selected depending on the average particle diameter and the like.

The zeta potential of magnesium carbonate may be adjusted depending on the drying temperature and the like. For example, the higher the temperature drying, the higher the zeta potential tends to be.

The specific surface area and the average particle diameter may be adjusted depending on the degree of curing of the magnesium carbonate slurry, and the like. For example, the specific surface area tends to be small and the average particle diameter tends to be small as the temperature during curing increases.

Further, the mercury penetration amount can be adjusted by the pressure at the time of dehydration (for example, pressing pressure of a filter press). There is a tendency for the mercury intrusion to increase at low pressures.

The average particle size may be adjusted depending on the degree of pulverization and the like.

[ use of magnesium carbonate ]

The use of the magnesium carbonate of the present invention is not particularly limited, and the magnesium carbonate can be used for various uses (for example, raw materials or components of paints, fertilizers, foods, cosmetics, ceramics, and pharmaceuticals).

Among these, the magnesium carbonate of the present invention can be preferably used as an additive for resins. In other words, the magnesium carbonate of the present invention may constitute a composition (resin composition).

By using the resin as an additive [ for example, a filler (filler, reinforcing agent) ], various physical properties and functions [ for example, strength, rigidity (modulus), and heat resistance ] can be enhanced (improved) or imparted. In addition, the amount of resin used can be increased, and depending on the type of resin, cost reduction can be achieved by mixing.

Thus, the invention also includes a composition comprising a resin and said magnesium carbonate.

The resin is not particularly limited, and may be a thermoplastic resin or a curable resin (for example, a thermosetting resin or a photocurable resin), or may be an elastomer (a thermoplastic elastomer, rubber, or the like).

The resins may be used singly or in combination of two or more.

Specific examples of the resin (including rubber) include an olefin resin (e.g., polyethylene, polypropylene, ethylene-propylene copolymer, etc.), a halogen-containing resin { e.g., a chlorine-containing resin [ e.g., a vinyl chloride-based resin (e.g., polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer, etc.), a vinylidene chloride-based resin (e.g., vinylidene chloride), etc. ], a (meth) acrylic resin (e.g., polymethyl methacrylate, methyl methacrylate-styrene copolymer, etc.), a styrene-based resin [ e.g., polystyrene, a styrene copolymer, or a styrene-containing resin (e.g., acrylonitrile-styrene copolymer, styrene-methacrylic acid copolymer, ABS resin, etc.) ], a polyester-based resin [ e.g., polyalkylene terephthalate (polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polycyclohexylenedimethylene terephthalate, etc.), polyarylate resin such as polyethylene naphthalate, etc.), polycarbonate resin (for example, bisphenol a type polycarbonate), polythiocarbonate resin, polyacetal resin, polyamide resin (for example, polyamide 6, polyamide 66, etc.), polyphenylene ether resin, polyether ketone resin, polysulfone resin, polyphenylene sulfide resin, polyimide resin, thermoplastic elastomer (olefin elastomer, styrene elastomer, polyester elastomer, polyamide elastomer, polyurethane elastomer, etc.), epoxy resin, phenol resin, urea resin, melamine resin, furan resin, unsaturated polyester resin, etc, Diallyl phthalate resins, vinyl ester resins, silicone resins, rubbers, and the like.

As the rubber, for example, diene rubber { e.g., Natural Rubber (NR), Isoprene Rubber (IR), butyl rubber (IIR), Butadiene Rubber (BR), Chloroprene Rubber (CR), nitrile-containing rubber [ e.g., nitrile-butadiene rubber (NBR), nitrile-chloroprene rubber (NCR), nitrile-isoprene rubber (NIR) ], styrene-containing rubber [ e.g., styrene-butadiene rubber (SBR), styrene-vinyl chloride rubber (SCR), styrene-isoprene rubber (SIR), etc. ], hydrogenated rubber [ e.g., hydrogenated nitrile-butadiene rubber (HNBR) ], olefin rubber [ e.g., ethylene-propylene-diene rubber (EPM), ethylene-propylene-diene rubber (EPDM), etc. ], acrylic rubber (ethylene-acrylic rubber, etc.), fluorinated rubber, urethane rubber, acid-modified rubber (e.g., carboxylated rubber (X-NBR), carboxylated styrene-butadiene rubber (X-SBR), Carboxylated ethylene-propylene rubber (X-EP (D) M), etc.).

Among these resins, olefin-based resins, halogen-containing resins, rubbers and the like are preferable, and vinyl chloride-based resins and rubbers are particularly preferable.

The magnesium carbonate is generally added to such a resin (rubber) with little decrease in transparency. Therefore, in addition to the use requiring transparency, the composition is less likely to affect the appearance and coloring, and thus can be suitably used for the use requiring appearance, design, coloring, and the like.

When the magnesium carbonate is added (mixed) to the resin, the proportion of the magnesium carbonate may be appropriately selected depending on the function to be imparted and the degree thereof, and is not particularly limited, and may be, for example, 0.1 part by mass or more (for example, 0.3 to 1000 parts by mass), preferably 0.5 part by mass or more (for example, 1 to 500 parts by mass), and more preferably 2 parts by mass or more (for example, about 3 to 300 parts by mass) with respect to 100 parts by mass of the resin.

In particular, when added to a resin such as an olefin resin or a halogen-containing resin (e.g., a vinyl chloride resin), the magnesium carbonate may be present in an amount of, for example, 0.1 to 100 parts by mass, preferably 0.5 to 80 parts by mass, more preferably 1 to 50 parts by mass (e.g., 2 to 30 parts by mass), particularly 3 to 25 parts by mass (e.g., 3.5 to 20 parts by mass, 4 to 15 parts by mass, 5 to 10 parts by mass, etc.), or 4 parts by mass or more (e.g., 5 parts by mass or more, 6 parts by mass or more, 7 parts by mass or more, 8 parts by mass, etc.) per 100 parts by mass of the resin (e.g., the olefin resin or the halogen-containing resin).

In particular, when added to the rubber, the proportion of magnesium carbonate may be, for example, 1 part by mass or more (for example, 1 to 1000 parts by mass), preferably 5 parts by mass or more (for example, 6 to 500 parts by mass), more preferably 8 parts by mass or more (for example, 10 to 300 parts by mass), particularly 15 parts by mass or more (for example, 20 to 200 parts by mass), and may be 30 parts by mass or more (for example, 40 parts by mass or more, 50 parts by mass or more, 60 parts by mass or more, 80 parts by mass or more, etc.) with respect to 100 parts by mass of the resin (rubber).

The composition may contain conventional additives such as plasticizers, flame retardants, softeners, stabilizers, antistatic agents, aging inhibitors, oxidation inhibitors, ultraviolet absorbers, adhesion imparting agents, lubricants, colorants, foaming agents, dispersants, fillers (other fillers not included in the scope of the magnesium carbonate) and the like, depending on the kind of the resin (rubber) and the use of the composition. The additives may be used singly or in combination of two or more.

The composition can be produced by mixing the respective components. The mixing method may be appropriately selected depending on the kind of the resin, and the like, and is not particularly limited,