JPH0560979B2 - - Google Patents

Description

[Detailed description of the invention]

"Industrial Application Field" The present invention relates to a glycol-based dispersion of calcium carbonate. More specifically, in order to improve the abrasion coefficient of polyester used as films or fibers, calcium carbonate is suspended in glycol such as ethylene glycol, which is a raw material during polyester production, and the dispersion stability in glycol is investigated. The present invention relates to a glycol-based dispersion of calcium carbonate, which is composed of calcium carbonate having good properties and affinity with polyester, and a glycol such as ethylene glycol, propylene glycol, butylene glycol, etc. "Prior Art and Problems" Today, industrially produced polyester,
In particular, polyethylene terephthalate (hereinafter referred to as PET)
) has excellent physical and chemical properties and is widely used in fibers, films, and other molded products. However, contrary to its excellent properties, it has poor slipperiness during the molding process, processing process, or handling of the product itself, resulting in poor workability and
It is known that undesirable problems such as a decrease in product value occur. Many of the causes are
This is due to the high friction coefficient of polyester itself. To solve these problems, many methods have been proposed to improve the surface smoothness of molded products by incorporating fine particles into polyester and giving the surface of the molded product appropriate irregularities, but the compatibility between the fine particles and polyester is insufficient. The transparency and abrasion resistance of the film and fibers were both unsatisfactory. Conventional methods for improving the surface properties of polyester include: Precipitating part or all of the catalyst used during polyester synthesis during the reaction process (internal particle precipitation method) Precipitating fine particles of calcium carbonate, silicon oxide, etc. during or during polymerization Many methods have been proposed for adding the particles later (external particle addition methods). However, since the particles are metal salts of the polyester component, the method for precipitating the internal particles has a certain degree of affinity with polyester. It is difficult to control and prevent the generation of coarse particles. On the other hand, in the method of adding external particles, if the particle size, amount added, etc. are appropriately selected, and fine particles from which coarse particles are removed by classification etc. are added, excellent slipperiness can be obtained. However, because the affinity between inorganic particles and the organic component polyester is insufficient,
During stretching, etc., peeling occurs at the interface between the particles and the polyester, creating voids. Therefore, there are problems to be solved in terms of transparency and abrasion resistance. To improve the affinity between inorganic particles and polyester, surface treatment using a coupling reaction between silane compounds or titanate compounds and inorganic particles has been proposed, but the treatment process is complicated and the effect is not as expected. Various problems arose. In addition, these inorganic compounds cannot be said to have good dispersion stability in glycol, and if glycol in which inorganic compounds are suspended is stored for a long period of time, the inorganic compounds will settle and form a hard cake. Another drawback is that redispersion becomes difficult, and that inorganic compounds aggregate in glycol or during the production of polyester. "Means for Solving the Problems" In view of the above-mentioned circumstances, the present inventors have conducted intensive studies on calcium carbonate, which has good dispersion stability in glycol, which is a raw material for producing polyester, and has good affinity with polyester. By wet-pulverizing calcium carbonate that has been surface-treated with a surface treatment agent of a specific composition in glycol, calcium carbonate that has good dispersion stability in glycol and good affinity with polyester can be obtained. They discovered this and completed the present invention. That is, the present invention provides a copolymer (A) of at least one selected from α,β monoethylenically unsaturated carboxylic acids and salts thereof and α,β monoethylenically unsaturated carboxylic acid esters and/or α, Calcium carbonate surface-treated with a salt (B) of a copolymer of β-monoethylenically unsaturated carboxylic acid and α,β-monoethylenically unsaturated carboxylic acid ester is used as a wet-pulverized raw material, and the wet-pulverized raw material is It contains a glycol-based dispersion of calcium carbonate made of calcium carbonate and glycol, which is prepared by wet-pulverizing a glycol slurry made of calcium carbonate and glycol. The surface treatment agent having the composition described in the present invention has α,β monoethylenically unsaturated carboxylic acid or α,β monoethylenically unsaturated carboxylic acid whose carboxyl group is an alkali metal, alkaline earth metal, ammonium, amine, etc. Neutralized alkali metal salts, alkaline earth metal salts, ammonium salts, etc.
At least one selected from amine salts, etc., and α,
Contains the above-mentioned salts of copolymers with β monoethylenically unsaturated carboxylic acid esters, and copolymers of α,β monoethylenically unsaturated carboxylic acids with α,β monoethylenically unsaturated carboxylic esters. Re,
These may be used alone or in combination of two or more. The α,β monoethylenically unsaturated carboxylic acids referred to in the present invention are α,β unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid, and α,β unsaturated acids such as maleic acid, fumaric acid, and itaconic acid. At least one type selected from dicarboxylic acids,
Typical α,β monoethylenically unsaturated carboxylic acid esters include acrylic acid, methacrylic acid, other alkyl esters, acrylates and methacrylates having an alkoxy group, and acrylates and metharylates having a cyclohexyl group. , acrylates and methacrylates having a hydroxyl group, polyalkylene glycol monoacrylates and monomethacrylates, etc., and at least one of α,β monoethylenically unsaturated carboxylic acid esters represented by these
Use seeds. Calcium carbonate used in the present invention is generally divided into two types: ground calcium carbonate and precipitated calcium carbonate (synthetic calcium carbonate). Heavy calcium carbonate is calcium carbonate prepared by mechanically pulverizing limestone and classifying the pulverized product into various grades.While it has the characteristic of being relatively inexpensive to produce, it has a poor particle size distribution. Calcium carbonate which is broad and has a fineness above a certain level has the disadvantage that it cannot be produced using current crushing and classification techniques. On the other hand, precipitated calcium carbonate is produced by calcining limestone at high temperatures, reacting the limestone with water to prepare lime milk, and then passing carbon dioxide gas generated during limestone calcining into the lime milk to synthesize calcium carbonate. Synthetic calcium carbonate is a synthetic calcium carbonate prepared by chemical methods such as a chemical compound process, a lime soda process in which milk of lime is reacted with soda carbonate, and a soda process in which calcium chloride is reacted with soda carbonate. Specifically, it has a sharp particle size distribution compared to heavy calcium carbonate, and it is also possible to select any particle size (primary particle size). In the present invention, it is possible to achieve the purpose of the present invention regardless of whether heavy calcium carbonate or precipitated calcium carbonate is selected, and the choice may be made as appropriate depending on the intended use, economic efficiency, desired particle size, etc. . In the present invention, methods for treating the surface of calcium carbonate with a surface treatment agent can be broadly classified into the following two methods. Dry treatment method Calcium carbonate powder is placed in a processing container equipped with rotating stirring blades such as a Henschel mixer, the powder is strongly stirred, and a water diluted solution or an organic solvent diluted solution of the surface treatment agent is added to the powder. A method for producing surface-treated calcium carbonate powder by dropping and dry surface treatment. Wet treatment method Add a diluted surface treatment agent in water or an organic solvent to a highly concentrated aqueous suspension of heavy calcium carbonate, a highly concentrated aqueous suspension of precipitated calcium carbonate, or a water-containing press cake, and stir vigorously. Then, prepare a surface-treated high-concentration calcium carbonate slurry, and if necessary, pass the surface-treated high-concentration calcium carbonate slurry through a wet grinder such as a sand grinder to perform a stronger surface treatment. A method for producing surface-treated calcium carbonate powder by drying a high-concentration calcium carbonate slurry using a dryer such as a drum dryer, and then pulverizing it using a pulverizer, performing wet surface treatment. Regardless of which of these two processing methods is used,
Although the object of the present invention can be achieved, in order to uniformly apply a surface treatment agent to the surface of each calcium carbonate particle and achieve the object of the present invention to a higher degree, it is better to use a wet treatment method, which is the method of preferable. The surface treatment agent used to surface treat the calcium carbonate surface by these treatment methods is as described above, but in order to more firmly apply the surface treatment agent to the surface of the calcium carbonate particles, it is necessary to combine the surface treatment agent and calcium carbonate. It is desirable that the particle surfaces be strongly bonded by a chemical reaction, and for this purpose a surface treatment agent that has residual active carboxyl groups that are reactive with calcium carbonate, i.e. α, β monoethylene, is used. In alkali metal salts, alkaline earth metal salts, ammonium salts, amine salts, etc. of α, β monoethylenically unsaturated carboxylic acids copolymerized with polyethylenically unsaturated carboxylic acid esters, alkali metals, alkaline earth metals, ammonium, The total amount of carboxyl groups neutralized with amine etc. is 100% of the total amount of all carboxyl groups in the copolymer.
A surface treatment agent that is less than 90%, more preferably 90% or less is used. The same applies when a copolymer of α,β monoethylenically unsaturated carboxylic acid and its ester is neutralized to form a salt. Further, the proportion of α,β monoethylenically unsaturated carboxylic acid ester in the entire copolymer is preferably 2 mol% or more and 95 mol% or less of the entire copolymer, and if it is less than 2 mol%, calcium carbonate and polyester are mixed together. In terms of the affinity of calcium carbonate, and if it exceeds 95 mol%, it is difficult to obtain sufficiently satisfactory results in terms of dispersion stability of the surface treatment high concentration water slurry of calcium carbonate in the surface treatment method. The surface treatment amount of the surface treatment agent is preferably 0.01% by weight or more and 30% by weight or less based on calcium carbonate as a pure component; if it is less than 0.01% by weight, it is difficult to obtain sufficiently satisfactory results in terms of treatment effect. Moreover, if it exceeds 30% by weight, it is not only economically disadvantageous, but also may have an adverse effect on the polyester itself. Furthermore, there are no particular limitations on the temperature at which these surface treatment agents are applied to the surface of calcium carbonate, but in order to achieve a stronger surface treatment, at least
The surface treatment is preferably carried out at a treatment system temperature of 30°C or higher, preferably 50°C or higher. As for the method of heating the surface treatment system at a high temperature, conventional methods may be followed; for example, in the treatment method, heating may be performed by passing hot water or steam into the external jacket of a treatment container such as a Henschel mixer; In the treatment method, the surface-treated calcium carbonate slurry may be heated by external heating. The surface-treated calcium carbonate powder prepared by the method described above is then mixed and stirred with glycol, such as ethylene glycol, propylene glycol, butylene glycol, which is a raw material for producing polyester, to form a glycol-based suspension of calcium carbonate. The glycol-based dispersion of calcium carbonate of the present invention is prepared by preparing a suspension and then passing the glycol-based suspension through a wet grinder to pulverize and disperse calcium carbonate. There is no particular limit to the concentration of calcium carbonate solids in the glycol-based suspension, but judging from economic efficiency, grinding efficiency, and viscosity of the glycol-based suspension, it is preferably 20% by weight or more and less than 80% by weight. . The wet pulverizer used in the wet pulverization of the present invention is a container filled with microparticles (media) such as natural or synthetic mineral sand, hard glass microparticles, hard plastic microparticles, metal microparticles, etc. This is a device that pulverizes particles by refluxing or passing a dispersion of the object to be treated while mechanically stirring the particles through a stirring blade such as a disk, bar, or screw. ,
This device is called a dyno mill or universal mill. The average particle size of the fine particles used in the wet grinder is preferably about 5 mm or less. There are no special restrictions when grinding and dispersing glycol-based suspensions using a wet grinder, and the desired particle size distribution,
In order to obtain calcium carbonate with the desired particle system, arbitrarily adjust the solid content concentration of the glycol-based suspension, the rotation speed of the stirring blades of the wet pulverizer, the filling rate of the media, the supply speed of the glycol-based suspension, etc. Just do it. The glycol-based dispersion of calcium carbonate prepared according to the present invention not only has good dispersion stability of calcium carbonate in glycol, but also has good affinity for calcium carbonate and polyester in polyester products prepared using these as raw materials. is extremely good. "Examples" The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited by these in any way. Calcium carbonate and surface treatment agents used in Examples and Comparative Examples are shown below. Calcium carbonate A: _CO2 concentration in ^7.2m3 of lime milk with a temperature of 30℃ and a specific gravity of 1.080.
25% furnace gas was introduced at a flow rate of 2 m ³ /min to perform the carbonation reaction, and the carbonation reaction was stopped when the system pH was 6.8.
An aqueous dispersion of precipitated calcium carbonate was obtained. The specific surface area of the precipitated calcium carbonate according to the BET method is 5.5.
m ² /g, and this calcium carbonate is referred to as calcium carbonate A. Calcium carbonate B: Commercially available heavy calcium carbonate (Super #1700, manufactured by Maruo Calcium) was designated as calcium carbonate B. The specific surface area measured by this constant pressure ventilation method is 1.08m ² /g.
It is. Surface treatment agent 1: Copolymer of 50 mol% acrylic acid and 50 mol% polyethylene glycol monomethacrylate Surface treatment agent 2: Ammonium salt of a copolymer of 80 mol% acrylic acid and 20 mol% propyl acrylate; 85% of all carboxyl groups in the polymer are neutralized with ammonium Surface treatment agent 3: Copolymer of 30 mol% acrylic acid and 70 mol% 2-hydroxyethyl acrylate Surface treatment agent 4: Surface treatment agent Sodium salt of No. 3, in which 50% of all carboxyl groups in the copolymer are neutralized with sodium Surface treatment agent 5: 70 mol% acrylic acid, 10 mol% maleic acid, 20 mol% methoxyethyl acrylate An amine salt of a copolymer in which 40% of the total carboxyl groups in the copolymer are neutralized with amine Surface treatment agent 6: 70 mol% acrylic acid, 10 mol% itaconic acid, cyclohexyl acrylate 20 mol% sodium salt of the copolymer, in which 40% of all carboxyl groups in the copolymer are neutralized with sodium Surface treatment agent 7: 90 mol% acrylic acid, methoxypolyethylene glycol polypropylene glycol A sodium salt of a copolymer of 10 mol% monomethacrylate, in which 100% of all carboxyl groups in the copolymer are neutralized with sodium.Surface treatment agent 8: A sodium salt of a copolymer of acrylic acid. , 100% of all carboxyl groups in the polymer are neutralized with sodium Surface treatment agent 9: Sodium stearate surface treatment agent 10: Ethylene glycol monomethacrylate monomer Example 1 Calcium carbonate A (concentration 16.8 The press cake (solid content concentration: 60%) obtained by dehydrating the water suspension (water suspension of Add 1% by weight of the pure component to 100% by weight, stir vigorously, and set the solid content at a surface treatment temperature of 70°C.
A surface treated calcium carbonate high concentration slurry of 60% calcium carbonate A was prepared. The high concentration surface-treated calcium carbonate slurry was dried and powdered using a spray dryer to obtain a surface-treated powder of calcium carbonate A. 50kg of this calcium carbonate A surface treated powder
Kg of ethylene glycol (manufactured by Mitsubishi Yuka Co., Ltd., fiber grade A) and stirred to prepare an ethylene glycol slurry of the wet-pulverized raw material. , manufactured by WAB, media 0.6~0.9mmφ
glass beads, media filling rate 80%, rotation speed
A dispersion of calcium carbonate A in ethylene glycol was prepared by passing the powder through wet milling twice at 1500 rpm. Example 2 An ethylene glycol dispersion of calcium carbonate A was prepared in the same manner as in Example 1 except for changing Surface Treatment Agent 1 to Surface Treatment Agent 2. Example 3 An ethylene glycol dispersion of calcium carbonate A was prepared in the same manner as in Example 1, except for changing surface treatment agent 1 to surface treatment agent 3 and changing the surface treatment amount to 2%. did. Example 4 An ethylene glycol dispersion of calcium carbonate A was prepared in the same manner as in Example 3, except that Surface Treatment Agent 3 was changed to Surface Treatment Agent 4. Example 5 An ethylene glycol dispersion of calcium carbonate A was prepared in the same manner as in Example 1, except that Surface Treatment Agent 1 was changed to Surface Treatment Agent 3 and the surface treatment temperature was changed to 40°C. . Example 6 10 kg of calcium carbonate B powder was put into a super mixer (SMV-20 type, manufactured by Kawada Seisakusho),
While fluidizing the powder by stirring the internal stirring blade of the mixer at 1200 rpm, 0.8% of surface treatment agent 5 was added as a pure component to calcium carbonate B, and stirring was continued for 15 minutes at a treatment temperature of 80°C to perform surface treatment. Surface-treated calcium carbonate B was obtained. 10kg of this surface treated powder of calcium carbonate B
Kg of ethylene glycol and stirred, after that,
An ethylene glycol dispersion of calcium carbonate B was prepared in the same manner as in Example 1. Example 7 An ethylene glycol dispersion of calcium carbonate B was prepared in the same manner as in Example 6, except that Surface Treatment Agent 5 was changed to Surface Treatment Agent 6. Example 8 70 kg of calcium carbonate B was suspended in 30 kg of water, and 1.5% by weight of surface treatment agent 7 was added as a pure content based on the solid content of calcium carbonate to the suspension, and the suspension was vigorously stirred.
A surface-treated calcium carbonate high concentration slurry of calcium carbonate B with a solid content concentration of 70% was prepared at a surface treatment temperature of 50°C. Furthermore, the surface-treated high-concentration calcium carbonate slurry was passed through a wet pulverizer (same as in Example 1) at a flow rate of 1/min to perform wet dispersion. The highly concentrated slurry of the surface-treated calcium carbonate thus obtained was dried and powdered using a spray dryer to obtain a surface-treated powder of calcium carbonate B. 50kg of this calcium carbonate B surface treated powder
Kg of ethylene glycol and stirred, after that,
An ethylene glycol dispersion of calcium carbonate B was prepared in the same manner as in Example 1. Comparative Example 1 An ethylene glycol dispersion of calcium carbonate A was prepared in the same manner as in Example 1, except that Surface Treatment Agent 1 was changed to Surface Treatment Agent 8. Comparative Example 2 30 kg of calcium carbonate B was suspended in 70 kg of water, and 3% by weight of a diluted surface treatment agent 9 in warm water was added to the suspension as a pure content based on the solid content of calcium carbonate. After stirring vigorously, the mixture was stirred using a filter press. The press cake (solid content concentration: 68%) obtained by dehydration was dried using a paddle dryer and pulverized using a wet pulverizer to obtain a surface-treated powder of calcium carbonate B. 30kg of this surface treated powder of calcium carbonate B
Kg of ethylene glycol and stirred, after that,
An ethylene glycol dispersion of calcium carbonate B was prepared in the same manner as in Example 1. Comparative example 3 Calcium carbonate B powder 50kg without surface treatment
was added to 50 kg of ethylene glycol and stirred, and thereafter an ethylene glycol dispersion of calcium carbonate B was prepared in the same manner as in Example 1. Comparative Example 4 Example 1 except that surface treatment agent 1 was changed to a mixture of surface treatment agent 8 and surface treatment agent 10 (a mixture in an equimolar ratio and without the addition of a polymerization initiator).
An ethylene glycol dispersion of calcium carbonate A was prepared in the same manner as described above. Application Example 1: Long-term stability of ethylene glycol dispersions One portion of each of the ethylene glycol dispersions of calcium carbonate prepared in Examples 1 to 8 and Comparative Examples 1 to 4
was placed in a measuring cylinder of No. 1 and allowed to stand for 60 days, and then the state of separation of calcium carbonate and ethylene glycol in the calcium carbonate ethylene glycol dispersion in each measuring cylinder and the state of the calcium carbonate settled at the bottom of the measuring cylinder were observed. did. The results of these measurements are shown in Table 1. The evaluation criteria during observation are as follows; ○: There is almost no separation of calcium carbonate and ethylene glycol, and the calcium carbonate that has settled at the bottom of the measuring cylinder is soft and can be easily redispersed. △: There is no separation between calcium carbonate and ethylene glycol. Although separation from ethylene glycol occurs, the calcium carbonate that settles at the bottom of the graduated cylinder is relatively soft.
Items that can be redispersed ×: The degree of separation between calcium carbonate and ethylene glycol is large, and the calcium carbonate that has settled at the bottom of the measuring cylinder has a hard cake shape, making redispersion difficult.Application example 2: Calcium carbonate Affinity between particles and PET resin 100 parts by weight of dimethyl terephthalate and 70 parts by weight of ethylene glycol were mixed with manganese acetate tetrahydrate.
After transesterification using 0.035 parts as a catalyst in a conventional manner, the ethylene glycol dispersions of calcium carbonate prepared in Examples 1 to 8 and Comparative Examples 1 to 4 were stirred so that the calcium carbonate concentration was 5000 ppm based on the polymer. Added. Thereafter, a polycondensation reaction was carried out in a conventional manner under high temperature vacuum to obtain polyethylene terephthalate having an intrinsic viscosity of 0.630. This polymer was melt extruded at 290°C and 3.5 mm in machine direction at 90°C.
After stretching 3.5 times in the transverse direction at 130°C, heat treatment was performed at 220°C to produce a film with a thickness of 15 μm.
After removing the surface polymer by etching these films and exposing the calcium carbonate,
The affinity between calcium carbonate and polyester was observed by measuring the void diameter (Db) and the calcium carbonate diameter (Dc) under a scanning electron microscope at a magnification of 20,000 times. The observation results are shown in Table 1. The observation criteria during observation are as follows; ◎: 1≦Db/Dc<1.2 Voids do not exist or are very small ○: 1.2≦Db/Dc<1.5 △: 1.5≦Db/Dc<3.0 ×: 3.0≦Db／Dc＜4.0

【table】

[Table] "Action/Effect" As mentioned above, the glycol-based dispersion of calcium carbonate of the present invention has excellent dispersion stability of calcium carbonate in glycol and compatibility with polyester in polyester products obtained using it as a raw material. It has good properties and improves the surface properties of polyester.

Claims (1)

[Scope of Claims] 1. A copolymer (A) of at least one member selected from α,β monoethylenically unsaturated carboxylic acids and salts thereof and α,β monoethylenically unsaturated carboxylic acid ester and/or Calcium carbonate surface-treated with a salt (B) of a copolymer of α,β monoethylenically unsaturated carboxylic acid and α,β monoethylenically unsaturated carboxylic acid ester is used as a raw material for wet grinding, and A glycol-based dispersion of calcium carbonate consisting of calcium carbonate and glycol, prepared by wet-milling a glycol slurry consisting of a pulverized raw material and glycol. 2. The glycol-based dispersion according to claim 1, wherein the proportion of α,β monoethylenically unsaturated carboxylic acid ester in the entire copolymer is 2 mol% or more and 95 mol% or less of the entire copolymer. body. 3. The amount of surface treatment of the copolymer used to surface treat calcium carbonate is
The glycol-based dispersion according to claim 1, which has a content of 0.01 wt% or more and 30 wt% or less.