JP3040564B2 - Anti-blocking agent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-blocking agent for synthetic resins composed of calcium carbonate having a specific form and a particle size distribution, and an object thereof is as an anti-blocking agent for synthetic resins such as polyolefins and polyesters. It is an object of the present invention to provide a material which is used, for example, such as a synthetic resin film and the like, which exhibits an excellent ability to prevent blocking.

[0002]

2. Description of the Related Art Synthetic resins are widely used for various industrial purposes. Among them, industrially produced polyester,
In particular, polyethylene terephthalate (hereinafter abbreviated as PET) has excellent physical and chemical properties,
Widely used as films and other molded products.
For example, in the film field, audio tapes, magnetic tapes such as video tapes, condensers, photos,
It is used for packaging and OHP.

[0003] In a polyester film, its slipperiness and abrasion resistance are major factors that affect the workability of the film manufacturing process and the working process in each application, and the quality of the product. When these slipperiness and abrasion resistance are insufficient, for example, when a magnetic layer is applied to the polyester film surface and used as a magnetic tape, the friction between the coating roll and the film surface during application of the magnetic layer is severe. Wear on the film surface is severe, wrinkles on the film surface in extreme cases,
Scratches occur. Also, even after slitting the film after applying the magnetic layer and processing it into audio, video, computer tape, etc., many guide parts, playback heads, etc., when pulling out from reels or cassettes, winding up and other operations Abrasion occurs significantly, and scratches, distortion occurs, and as a result of precipitation of a white powdery substance due to abrasion of the polyester film surface, a lack of a magnetic recording signal,
That is, it often causes a large dropout.

Conventionally, there are many methods for lowering the coefficient of friction of polyester by incorporating inorganic fine particles into the polyester and imparting fine and appropriate irregularities to the surface of the molded product to improve the surface smoothness of the molded product. Although proposed, the affinity between the fine particles and the polyester was not sufficient, and neither the transparency nor the abrasion resistance of the film were satisfactory. Particles that form irregularities on the surface of these polyester films generally have a greater slipperiness improving effect as their size is larger.However, for magnetic tapes, particularly precision applications such as video, Since the large particles themselves can cause defects such as dropouts, the unevenness of the film surface needs to be as fine as possible, and at present, there is a demand to satisfy these conflicting properties at the same time. is there.

In order to improve the dispersibility of these inorganic fine particles and polyester in a polyester, a glycol slurry of inorganic compound fine particles is prepared and added to a polyester production process. The dispersibility and dispersion stability are not good, and when glycol containing inorganic fine particles is stored for a long period of time, the inorganic compound precipitates and forms a hard hard cake, and it is difficult to redisperse. In addition, there is a disadvantage that the inorganic fine particles are aggregated in the glycol or during the production of the polyester. The presence of agglomerated coarse particles in the polymer may cause yarn breakage during spinning, or may cause coarse protrusions and fish eyes in the film. In particular, when used for magnetic tape films, dropout or S / S Development of fine particles that do not generate agglomerated coarse particles has been awaited to cause a decrease in the N ratio.

On the other hand, polyolefins, like polyesters, are widely used as industrial products for various purposes.
In particular, biaxially oriented polyolefin films such as polypropylene films are most widely used as various packaging materials. This kind of polyolefin film is easy to cause blocking because it is sticky as is well known,
This not only impairs the workability in the production and further processing of the film, but also tends to cause troubles such as poor opening of the bag when the film is used for packaging or packaging. Therefore, this kind of film is usually subjected to a blocking resistance treatment, as a blocking inhibitor, finely divided silica, zeolite, calcium carbonate,
Or kaolin clay is typical.

[0007] The polyolefin film is required to have excellent transparency as a quality characteristic. However, the transparency and the blocking resistance are contradictory quality characteristics, and the blocking resistance of the polyolefin film is improved. When a large amount of an antiblocking agent is used for the purpose, the transparency of the polyolefin film decreases with an increase in the amount of the antiblocking agent, and both of these blocking resistance and transparency can be effectively satisfied. As a modifying additive, any of the conventional inorganic powders has disadvantages.

For example, conventionally used kaolin clay has a plate-like particle shape, so that it is used as an anti-blocking agent for a polyolefin film to form sufficient unevenness on the surface of the polyolefin film. Therefore, good blocking resistance could not be obtained unless used in a large amount, and as a result, only a polyolefin film having insufficient transparency was obtained. Similarly, when fine silica powder is used, since the basic particles are extremely fine, a good polyolefin film can be obtained from the viewpoint of transparency, but sufficient irregularities are formed on the surface of the polyolefin film even when used in large amounts. Therefore, a sufficient polyolefin film could not be obtained from the viewpoint of a blocking prevention function. In addition, when zeolite powder is used, kaolin clay, compared with finely divided silica, relatively good transparency, although a polyolefin film having blocking resistance can be obtained, since zeolite has water of crystallization as is well known. ,
Under the heating conditions during molding and film formation of synthetic resin,
The foaming phenomenon accompanying the detachment of the water of crystallization often occurs to give defective products. Even if the zeolite is heat-treated to remove the so-called zeolite water to form an activated zeolite anhydrous, this water easily re-adsorbs. It was impossible to eliminate the effect.

Furthermore, when calcium carbonate, which has been used conventionally, is used, since there is no crystallization water in calcium carbonate, there is no foaming phenomenon accompanying withdrawal of water of crystallization. Since secondary coarse particles in which a large number of particles are aggregated are easily formed, there is a problem to be improved as a blocking inhibitor for polyolefin films having both good blocking resistance and transparency.

[0010] Generally, calcium carbonate is used in papermaking, paint,
It is used in various fields as a filler for rubber and plastic. This calcium carbonate is generally heavy calcium carbonate and precipitated calcium carbonate (synthetic calcium carbonate)
Are roughly divided into two types.

[0011] Heavy calcium carbonate is a calcium carbonate prepared by mechanically pulverizing limestone and classifying the pulverized material to classify it into various grades, and has a feature that it can be produced relatively inexpensively. On the other hand, it is impossible to classify coarse particles and fine particles completely with the current classification technology, and as a result, calcium carbonate having a broad particle size distribution and a certain degree of fineness cannot be produced by the current pulverization classification technology. Therefore, it was not suitable as an anti-blocking agent for synthetic resin films such as polyolefin films.

On the other hand, as an industrial production method of synthetic calcium carbonate, a carbon dioxide gas method is widely adopted. In the carbon dioxide method, natural limestone is calcined to obtain quicklime (calcium oxide), and the quicklime is reacted with water to obtain lime milk (a suspension of calcium hydroxide in water). This is a method of obtaining calcium carbonate by conducting carbon dioxide gas generated when limestone is calcined and causing it to react. Synthetic calcium carbonate produced by this carbon dioxide method originally has a very strong cohesive force between primary particles,
A large number of primary particles aggregate to form large secondary particles (coarse aggregates of primary particles), and the slurry of the secondary particles is dispersed to almost the primary particles even if stirring is continued vigorously for a long time. That is said to be impossible. When synthetic calcium carbonate containing a large number of aggregates of such primary particles is used as a filler or pigment for various applications, secondary particles behave as if they were primary particles, poor dispersion, reduced strength, Good physical properties such as a decrease in gloss and a deterioration in fluidity cannot be obtained, and a compounding effect as in the case where primary particles are originally mixed cannot be obtained. Similarly, even if a synthetic calcium carbonate containing such a large number of aggregates is treated with an inorganic or organic surface treating agent, only the surface of the secondary particles is treated, and a sufficient effect is obtained. It doesn't work.

[0013] To date, there have been reported a number of methods for dispersing these primary particle aggregates.
A method of strongly pulverizing and breaking by a sand grinder mill or the like is employed. However, since such a method is grinding and pulverization using a large amount of energy, the aggregates are dispersed and the primary particles are destroyed at the same time, and as a result, the surface state is very unstable and desired. This is a preferable method because particles smaller than the primary particle diameter and secondary agglomerated particles with incomplete dispersion are mixed and the particle size distribution is widened. Also,
In a wet pulverizer such as a sand grinder, fine glass beads are usually used as a pulverizing medium.However, since the surface of these glass beads is also pulverized and destroyed during the pulverization and destruction step of calcium carbonate, A large number of coarse glass pieces of about 20 μm will be mixed in calcium, and for example, it is not possible to disperse and prepare calcium carbonate such as used as a filler for a thin film having a thickness of about 15 μm using such a wet grinding method. Not preferred. For the above reasons, conventional synthetic calcium carbonate was not sufficient as an anti-blocking agent for synthetic resin films such as polyolefin films.

[0014]

In view of the above facts, the present invention provides a synthetic resin such as a polyolefin film with good blocking resistance and good transparency.
Another object of the present invention is to provide an anti-blocking agent which does not cause a foaming phenomenon in a film forming step or the like.

[0015]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in an attempt to solve the above problems, and as a result, have found that a specific particle size,
The inventors have found that calcium carbonate having a specific particle size has a function as an intended antiblocking agent, and completed the present invention.

That is, the present invention provides the following (A), (A),
It is a blocking inhibitor for synthetic resin made of calcium carbonate which satisfies all of the requirements of (c), (d), (e) and (f). (A) 0.1 μm ≦ DS1 ≦ 10 μm (A) 0.033 μm ≦ DS2 ≦ 10 μm (C) DP3 / DS1 ≦ 1.25 (D) 1.0 ≦ DP2 / DP4 ≦ 2.5 (E) 1.0 ≤DP1 / DP5≤4.0 (f) (DP2-DP4) /DP3≤1.0, where DS1: average particle diameter (μm) of the major axis of primary particles examined by a scanning electron microscope (SEM) DS2: Average particle diameter (μm) of the short diameter of the primary particles examined by the above microscope DP1: Light transmission type particle size distribution analyzer (SA- manufactured by Shimadzu Corporation)
In the particle size distribution measured using CP3), the particle size (μ
m) DP2: In the particle size distribution measured using the above measuring device, the particle size (μm) at 25% of the cumulative weight calculated from the larger particle diameter side DP3: In the particle size distribution measured using the above measuring device, Particle size at 50% cumulative weight calculated from particle size side (μm) DP4: Particle size at 75% cumulative weight calculated from large particle size side (μm) DP5: particle size (μm) at a cumulative weight of 90% calculated from the larger particle size side in the particle size distribution measured using the above measuring instrument.

The measurement of the particle size by the light transmission type particle size distribution analyzer in the present invention is measured and calculated in the following manner. Measurement model: Shimadzu SA-CP3 Measurement method: Solvent: 0.004 sodium polyacrylate in ion-exchanged water
Preliminary dispersion: 100 seconds of ultrasonic dispersion Measured temperature: 27.5 ° C. ± 2.5 ° C. Measurement method: The following calculation example is used. DP1, 2, 3, calculated from the above particle size distribution measurement results
4 and 5 are as follows: DP1 = 2.00 + (11.0-10.0) x (3.00-2.00) ÷ (11.0-6.0) = 2.20 DP2 = 0.80 + (28.0-25.0) x (1.00-0.80) ÷ ( 28.0 -18.0) = 0.86 DP3 = 0.50 + (58.0 -50.0) x (0.60-0.50) ÷ (58.0 -42.0) = 0.55 DP4 = 0.30 + (82.0 -75.0) x (0.40-0.30) ÷ (82.0-72.0) = 0.37 DP5 = 0.15 + (94.0-90.0) x (0.20-0.15) ÷ (94.0-89.0) = 0.19 The DS of the present invention was measured using a scanning electron microscope manufactured by Hitachi, Ltd.

In the anti-blocking agent for synthetic resins of the present invention, DS1 and DS2 are 0.1 μm ≦ DS1 ≦ 10
μm, 0.033 μm ≦ DS2 ≦ 10 μm, preferably 0.1 μm ≦ DS1 ≦ 5 μm, 0.033 μm ≦ DS2
≦ 5 μm, and may be arbitrarily selected depending on the type of synthetic resin, application, and other required physical properties. For example, in fields requiring higher physical properties such as magnetic tapes for audio and video, DS1 and DS2 are particularly preferably 2 μm or less. In addition, polyolefin films used for applications such as packaging include 1 μm ≦ DS1 ≦ 5 μm
m, 0.5 μm ≦ DS2 ≦ 5 μm is particularly preferred. D
When S1 and DS2 are more than 10 μm, for example, in the film field, not only the transparency of the film is hindered, but also a large number of coarse projections are present on the film surface, and the smoothness of the film surface is significantly deteriorated, which is not preferable. . On the other hand, DS1 is less than 0.1 μm and DS2 is 0.1 μm.
If it is less than 033 μm, an anti-blocking agent capable of imparting sufficient blocking resistance to the synthetic resin even if used in a large amount cannot be obtained.

The shape of the anti-blocking agent of the present invention is not particularly limited. However, in general, the anti-blocking agent having a flat plate-like structure requires a large amount of anti-blocking to obtain a sufficient anti-blocking effect from its shape effect. It is necessary to use an agent, and the transparency and flexibility of a film or the like may be impaired. For DS1 / DS2 which is a function relating to an antiblocking agent, 1 ≦ DS1 / D
It is preferably in the range of S2 ≦ 3, more preferably 1
≤DS1 / DS2≤2, more preferably 1≤DS1 /
DS2 ≦ 1.5.

DP3 / DS1 and (DP2-DP4) / DP, which are functions relating to the state of dispersion of the antiblocking agent
3 is DP3 / DS1 ≦ 1.25, (DP2-DP4)
/DP3≦1.0, and DP3 / DS1 is 1.
When the ratio exceeds 25, and when (DP2-DP4) / DP3 exceeds 1.0, the antiblocking agent is constituted by a large number of secondary particles, which is preferable from the viewpoint of designing the performance of the synthetic resin molded product. Without, for example, in the film field, the size of the unevenness of the film surface obtained by such an antiblocking agent also becomes uneven,
A film having sufficient blocking resistance cannot be obtained. Therefore, (DP2-DP4) / DP3 is preferably 0.5 or less for polyolefins and the like used for advanced industrial applications, and in fields requiring higher physical properties such as magnetic tapes for audio and video. Is (DP2
-DP4) / DP3 is particularly preferably 0.35 or less.

The functions DP2 / DP4 and DP1 / DP5 relating to the particle size composition of the antiblocking agent are 1.0
≤DP2 / DP4≤2.5, 1.0≤DP1 / DP5≤
4.0, and for applications requiring more advanced physical properties, 1.0 ≦ DP2 / DP4 ≦ 2.0, 1.0 ≦ D
It is preferable that P1 / DP5 ≦ 3.0. DP2 /
When DP4 exceeds 2.5, and when DP1 / DP5 exceeds 4.0, the particle size distribution width becomes broad, and fine particles unnecessary for antiblocking ability and coarse projections on the surface of a synthetic resin molded product such as a film. Since the content of the coarse particles causing the increase is large, an antiblocking agent capable of imparting sufficient blocking resistance and good transparency to a synthetic resin molded product such as a synthetic resin film cannot be obtained.

The crystal form of calcium carbonate used in the present invention is not particularly limited, and one of hexagonal calcite-type crystals, orthorhombic aragonite crystals, and pseudo-hexagonal vaterite-type crystals Alternatively, two or more kinds can be used, and cubic, spherical calcite-type calcium carbonate and spherical vaterite-type calcium carbonate are preferable from the viewpoint of uniformity of particle shape, dispersibility of particles, and the like.

Examples of the method for producing calcium carbonate that can be used in the present invention include a carbonate ion solution (eg, sodium carbonate) and a calcium solution (eg, calcium chloride) in which a reaction buffer (eg, sodium sulfate) for controlling the particle shape is dissolved. Are mixed, and a crystal growth terminator (eg, sodium hydroxide) is added during the reaction of the mixture to control the particle size, and by controlling the reaction conditions, a cubic calcite-type carbonate having an arbitrary particle size is obtained. It is possible to prepare calcium or spherical vaterite-type calcium carbonate. In addition, carbon dioxide gas is passed through a methanol suspension of quicklime or slaked lime containing a specific amount of quicklime or slaked lime and a specific amount of water to perform a carbonation reaction, and the temperature in the reaction system at a specific point in time during the carbonation reaction. Is adjusted to a specific temperature, and by specifying the time at which the conductivity in the reaction system reaches a specific value from the start of the carbonation reaction, spherical or elliptical spherical vaterite calcium carbonate having an arbitrary particle diameter is produced. It is possible.

However, the calcium carbonate for achieving the object of the present invention is not particularly limited to the above-mentioned production method, and any calcium carbonate satisfying the above requirements (A) to (F) can be used. Needless to say, it is not possible.

The calcium carbonate used in the present invention may contain organic acids such as fatty acids, resin acids, organic acids such as acrylic acid, oxalic acid and citric acid, tartaric acid, etc. in order to further enhance the dispersibility and stability of the particles. Inorganic acids such as phosphoric acid, condensed phosphoric acid and hydrofluoric acid, surface treatment agents such as polymers thereof, salts thereof and esters thereof, dispersants such as surfactants, titanate coupling agents, silane coupling agents, etc. It is preferably used after surface treatment with a coupling agent or the like according to a conventional method.

There are no particular restrictions on the type of synthetic resin or synthetic resin molded product applicable to the anti-blocking agent of the present invention, but it is particularly suitable for polyolefin and polyester films. The polyolefin is not particularly limited as long as it has a transparent and crystalline self-supporting film-forming ability. For example, a crystalline homopolymer of an α-olefin having about 2 to 12 carbon atoms, two or more kinds Crystalline copolymers, specifically, polyethylene, polypropylene, poly-4-methylpentene-1, ethylene-propylene random or block copolymer, ethylene-propylene-butene copolymer, ethylene-propylene-hexene copolymer Coalescence and the like. Among them, polypropylene and propylene majority weight propylene and other α-
A polymer with an olefin is preferable, and a propylene polymer having an ethylene content of 0 to 6% by weight is particularly preferable. Further, these polyolefins are crystalline, and those having an isotactic index (II) of usually 40 or more, especially 60 or more, particularly 90 or more are suitable. Further, it is used as long as it can be molded, but usually has a melt flow rate (MFR) of 0.01 to 100 g / 10 min, especially 0.1 to 100 g / 10 min.
Those having 1 to 50 g / 10 min, particularly 0.5 to 10 g / 10 min are preferable.

The polyester is not particularly limited as long as it is a polyester containing an aromatic dicarboxylic acid as a main acid component and an aliphatic glycol as a main glycol component. Such polyesters are substantially linear and have film-forming properties, especially by melt-forming. Examples of the aromatic dicarboxylic acid include terephthalic acid, naphthalenedicarboxylic acid, isophthalic acid, diphenylethanedicarboxylic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenylsulfondicarboxylic acid, diphenylketonedicarboxylic acid, and anthracenedicarboxylic acid. it can. Examples of the aliphatic glycol include ethylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol,
Examples thereof include polymethylene glycol having 2 to 10 carbon atoms such as decamethylene glycol and alicyclic diols such as cyclohexanedimethanol.

In the present invention, polyesters containing, for example, alkylene terephthalate and / or alkylene naphthalate as a main component are preferably used. Among these polyesters, for example, polyethylene terephthalate and polyethylene-2,6-naphthalate, for example, terephthalic acid and / or 2,6-naphthalenedicarboxylic acid account for at least 80 mol% of all dicarboxylic acid components, and all glycols. A copolymer in which 80% by mole or more of the component is ethylene glycol is preferred. At that time, 20 mol% or less of the total acid component can be the above-mentioned aromatic dicarboxylic acid other than terephthalic acid and / or naphthalenedicarboxylic acid.
It can be an aliphatic dicarboxylic acid such as sebacic acid; an alicyclic dicarboxylic acid such as cyclohexane-1,4-dicarboxylic acid. Also, 20 mol% or less of the total glycol component can be the above-mentioned glycol other than ethylene glycol, or for example, hydroquinone,
Aromatic diols such as 2-bis (4-hydroxyphenyl) propane; aliphatic diols containing aromatics such as 1,4-dihydroxymethylbenzene; polyalkylene glycols such as polyethylene glycol, polypropylene glycol and polytetramethylene glycol (Polyoxyalkylene glycol) and the like.

The polyester may further comprise a component derived from an oxycarboxylic acid such as an aromatic oxyacid such as hydroxybenzoic acid; an aliphatic oxyacid such as ω-hydroxycapric acid, a dicarboxylic acid component and an oxycarboxylic acid. Those that copolymerize or combine at 20 mol% or less based on the total amount of the components are also included. Further, the polyester may have an amount in a substantially linear range, for example, an amount of 2 mol% or less based on the total acid content, such as a tri- or higher functional polycarboxylic acid or polyhydroxy compound such as trimellitic acid or pentaerythritol. And copolymers thereof. As other synthetic resins, polyamides such as nylon 66 and nylon 6, and halogen-containing polymers such as polyvinyl chloride can be applied.

The amount of the anti-blocking agent of the present invention to be blended with such a synthetic resin as an anti-blocking agent is not uniform depending on the use of the film, the type of the synthetic resin, etc. Synthetic resin film 1
0.01 to 3 parts by weight per 100 parts by weight is appropriate, and particularly preferably 0.01 to 1 part by weight. The reason for this is that if the amount is less than the lower limit, the desired anti-blocking effect is insufficient due to the small amount of addition, and the accuracy of uniformly dispersing the compounded resin in the synthetic resin is reduced.
On the other hand, if it exceeds the upper limit, the transparency of the film is impaired, the block resistance is not improved for the added amount, and the stretchability of the film is undesirably reduced.

The anti-blocking agent of the present invention may include other additives used in synthetic resins such as polyolefins and polyesters, for example, pigments, dyes, ultraviolet absorbers, various stabilizers,
The anti-blocking agent of the present invention can be used in combination with various additives such as an antioxidant, a light-shielding agent (eg, carbon black, titanium dioxide, etc.), a processing aid, an antistatic agent, and, if necessary, other anti-blocking agents. Can be used together.

In producing a film using the anti-blocking agent according to the present invention, for example, the polyolefin composition is biaxially stretched by a conventional method, so that it has good workability, no foaming property, and transparency and blocking resistance. Can be produced. Further, the anti-blocking agent of the present invention is also suitable as an anti-blocking agent for molded articles of synthetic resins such as fibers and sheets,
Further, it can be suitably used as a surface modifier and a filler for synthetic resin tracing paper such as a polyester film.

[0033]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples, which do not limit the present invention. Example 1 20 liter of 1.0 mol / l sodium carbonate aqueous solution and 0.2 mol / l sodium sulfate aqueous solution 2
While stirring 0 liter of the mixed solution in the reaction tank, 20 liters of 0.8 mol / liter calcium chloride aqueous solution was added thereto at a charging rate of 0.4 liter per second, and the carbonation reaction was performed with stirring. When the pH of the reaction system reached 11.0, sodium hydroxide was added so that the pH of the reaction system became 12.0, and then the mixture was stirred for 5 minutes to complete the reaction. The liquid temperatures before and after the reaction were 17.2 ° C and 17.0 ° C, respectively.
Was adjusted. Thereafter, dehydration was carried out in accordance with a conventional method, and the dehydrated cake was sufficiently washed with ion-exchanged water. Then, a surface treatment agent (sodium stearate) corresponding to 0.5% by weight of the obtained calcium carbonate was subjected to surface treatment under stirring. After drying, an anti-blocking agent composed of calcium carbonate powder was obtained. As a result of X-ray diffraction measurement, the obtained calcium carbonate powder was 100% vaterite-type calcium carbonate.
As a result of observation with M, it was cubic calcium carbonate having a particle size of 0.8 to 3 μm. Table 2 shows special values relating to the form, dispersity, and particle size of the calcium carbonate obtained in this example.

Example 2 An anti-blocking agent composed of calcium carbonate powder was obtained in the same manner as in Example 1 except that the charging rate of the aqueous solution of calcium chloride was changed to 0.5 liter per second.
As a result of X-ray diffraction measurement,
It was 00% calcite-type calcium carbonate. As a result of observation by SEM, it was a cubic calcium carbonate having a particle diameter of 1 to 4 μm. Table 2 shows special values relating to the form, dispersity, and particle size of the calcium carbonate obtained in this example.

Example 3 An anti-blocking agent composed of calcium carbonate powder was obtained in the same manner as in Example 1 except that the rate of introducing the aqueous solution of calcium chloride was changed to 0.667 liters per second. As a result of X-ray diffraction measurement, the obtained calcium carbonate powder was 100% calcite-type calcium carbonate.
As a result of observation with M, it was cubic calcium carbonate having a particle size of 1 to 6 μm. Table 2 shows special values relating to the form, dispersity, and particle size of the calcium carbonate obtained in this example.

Example 4 20 liters of a 0.7 mol / l sodium carbonate aqueous solution and 0.2 mol / l sodium sulfate aqueous solution 2
While stirring 0 liter of the mixed solution in the reaction vessel, 20 liters of a 0.53 mol / l aqueous solution of calcium chloride was added thereto at a charging rate of 0.33 liters per second, and the carbonation reaction was carried out with stirring. When the pH of the reaction system reached 10.7, sodium hydroxide was added so that the pH of the reaction system became 12.0, and then the mixture was stirred for 5 minutes to complete the reaction. The liquid temperatures before and after the reaction were 17.2 ° C. and 17.0 ° C., respectively.
Adjusted to ° C. Thereafter, the cake is sufficiently dehydrated according to a conventional method, and the dehydrated cake is sufficiently washed with ion-exchanged water. Then, a surface treatment agent (each weight ratio of acrylic acid and butyl methacrylate) corresponding to 1.5% by weight based on the obtained calcium carbonate is used. Is a 70:30 copolymer, in which 20% of the total carboxyl groups of the acrylic acid portion are ammonium salts), and the resulting mixture is subjected to surface treatment under stirring, followed by spray drying using a spray drier. An anti-blocking agent consisting of calcium carbonate powder was obtained. The obtained calcium carbonate powder is X
As a result of the line diffraction measurement, it was 88% vaterite-type calcium carbonate and 12% calcite-type calcium carbonate.
As a result of the observation, spherical calcium carbonate and cubic calcium carbonate having a particle diameter of 0.8 to 4 μm were obtained. Table 2 shows special values relating to the form, dispersity, and particle size of the calcium carbonate obtained in this example.

COMPARATIVE EXAMPLE 1 Water content was added to slaked lime to prepare calcium hydroxide at a concentration of 3
Milk casein was dissolved in calcium hydroxide in lime milk in an amount of 20% by weight, and the lime milk was adjusted to 3 ° C., and then 0% based on 1 mol of calcium hydroxide in lime milk. Carbon dioxide gas was passed at a conduction rate of 0.822 liters / minute to carry out carbonation reaction, and the carbonation reaction was completed at pH 6.5. After the carbonation reaction was completed, the mixture was allowed to stand for 24 hours, and then dehydrated by a conventional method. The obtained dehydrated cake was dried at 80 ° C. to obtain a blocking inhibitor composed of calcium carbonate powder. As a result of X-ray diffraction measurement, the obtained calcium carbonate powder was 95% vaterite-type calcium carbonate. Table 3 shows special values relating to the form, the degree of dispersion, and the particle size of the antiblocking agent obtained in this comparative example.

Comparative Example 2 CO ₂ was added to 7.2 m ³ of lime milk at a temperature of 15 ° C. and a specific gravity of 1.070.
20% of furnace gas (hereinafter abbreviated as CO ₂ gas) having a concentration of 25%
The reaction was conducted at a flow rate of m ³ / min to complete the carbonation reaction. After the completion of the carbonation reaction, the temperature of the system was adjusted to 50 ± 5 ° C., the pH was adjusted to 10 ± 0.5 using CO ₂ gas and lime milk, and the mixture was stirred for 24 hours, and a viscous precipitated calcium carbonate aqueous solution having a viscosity of 2000 cps was obtained. A dispersion was obtained. 50 ± 5 ° C.該沈were prepared later made calcium carbonate aqueous dispersion (solid content concentration 14.9%) to 4m ³ milk of lime having a specific gravity of 1.070 was added dropwise at a rate of 0.6 m ³ / hr, at the same time CO ₂ The gas was passed, and the carbonation reaction was carried out at a system pH of 10 ± 0.5 with stirring. When the total amount of the lime milk drop reached 56 m ³ , the dropping of the lime milk was stopped, and the pH of the system was reduced to 7.0 until the pH reached 7.0.
O ₂ gas was passed through, and the obtained calcium carbonate was added at 0.1%.
A surface treatment agent (sodium stearate) corresponding to 5% by weight was subjected to surface treatment under stirring conditions, followed by dehydration and drying to obtain a calcium carbonate powder antiblocking agent. As a result of X-ray diffraction measurement, the obtained calcium carbonate powder
It was 0% calcite-type calcium carbonate. As a result of observation by SEM, it was a cubic calcium carbonate having a particle diameter of 0.8 to 3 μm. Table 3 shows special values relating to the form, degree of dispersion, and particle size of the calcium carbonate obtained in this comparative example.

Comparative Example 3 Heavy calcium carbonate (Super 1700: manufactured by Maruo Calcium Co., Ltd.) powder was suspended in warm water at 50 ° C. to obtain a calcium carbonate warm water suspension having a solid concentration of 15% by weight.
A surface treatment agent (sodium stearate) corresponding to 0.5% by weight of calcium carbonate was subjected to surface treatment under stirring, followed by dehydration and drying to obtain a blocking inhibitor composed of calcium carbonate powder. The obtained calcium carbonate powder was 100% calcite-type calcium carbonate as a result of X-ray diffraction measurement. As a result of observation by SEM, the particle size was 0.3 to 9 μm.
m of irregularly shaped calcium carbonate. Table 3 shows special values relating to the form, degree of dispersion, and particle size of the calcium carbonate obtained in this comparative example.

Application Example A Using the anti-blocking agents prepared in Examples 1 to 4 and Comparative Examples 1 to 3, and A-type zeolite, kaolin clay and synthetic silica which are commercially available as anti-blocking agents for comparison, A polypropylene composition was prepared in the following manner, a biaxially stretched polypropylene film was obtained, and its quality was evaluated. The results were as shown in Table 1.

Production of Film 100 parts by weight of a polypropylene resin having a melt flow rate of 1.9 g / 10 minutes, 0.10 parts by weight of 2,6-di-t-butyl-p-cresol as an antioxidant, Irganox 1010 (Product name, made by Ciba Geigy) 0.02
Parts by weight, 0.05 parts by weight of calcium stearate as a hydrochloric acid catching agent, and 0.08 parts by weight or 0.15 parts by weight of the antiblocking agent of the present invention were added, mixed with a super mixer, and then pelletized with an extruder. The pellets are formed into a sheet-like film using an extruder,
Stretched 5 times in the vertical direction and 10 times in the horizontal direction to finally achieve a thickness of 30
A μm stretched film was obtained. On one side of the stretched film,
Corona discharge treatment was performed.

With respect to these biaxially stretched films, transparency, blocking properties and foaming properties were measured. Film transparency was measured by stacking four films in accordance with ASTM-D-1003. The blocking property of the film is 2
The films are stacked so that the contact area of the films becomes 10 cm ² , placed between two glass plates, and left under a load of 50 g / cm ² in an atmosphere of 40 ° C. for 7 days, and then using a shopper type tester. Then, it was peeled off at a pulling speed of 500 mm / min, and the maximum load was read and evaluated. The foaming property of the film is 100 parts by weight of resin [polyethylene (SMA)
-110)], a mixture of 1 part by weight of the sample is kneaded with a roll at 170 ° C. for 5 minutes, and then press-molded at 170 ° C. for 4 minutes to a thickness of 1 mm to obtain a sample plate. The sample plate is sandwiched between glass plates like a sandwich layer and placed in a heating oven for 2 hours.
It was left at 30 ° C. for 1 hour to observe the foaming state. The evaluation of the foaming property was visually evaluated according to the following criteria, and evaluated in four steps. 1: not foam at all like the blank 2: slightly foamed 3: considerably foamed 4: significantly foamed

[0043]

[Table 1]

Example 5 Granular quicklime having an activity of 82 (special grade reagent) was pulverized with a dry pulverizer (Coloplex; trade name, manufactured by Alpine).
The obtained quicklime powder was put into methanol, coarse particles were removed using a 200-mesh sieve, and a quicklime methanol suspension having a solid concentration of 20% as quicklime was prepared. The methanol suspension is wet-milled (Dynomill P
ILOT type; trade name, manufactured by WAB)
Methanol suspension dispersion D ₁ of the quicklime was prepared. The quicklime methanol added added to methanol suspension dispersion D _1, diluted to quicklime concentration of 3.0 wt%, further added 11 times equivalent moles of water to quicklime,
Methanol - quicklime - to prepare a mixed system M ₁ of water. 20
After adjusting the mixed system M ₁ containing quicklime 0g to 42 ° C., the carbon dioxide gas conductive for a conduction rate of quicklime per mole 0.082 mole / min in stirred conditions the mixed system, the carbonation reaction Started. Five minutes after the start of the carbonation reaction, the conductivity in the system reached the maximum point, and the temperature in the system at the maximum point was adjusted to 45 ° C. Thereafter, the carbonation reaction was continued. When the electric conductivity in the system reached 100 μS / cm 19 minutes after the start of the carbonation reaction, the supply of carbon dioxide gas was stopped, and the carbonation reaction was stopped. The obtained calcium carbonate was analyzed by X-ray diffraction.
It was 100% vaterite type elliptical spherical calcium carbonate.

In a mixed system M ₂ of methanol, water and calcium carbonate prepared by the above method, a surface treating agent (each weight ratio of acrylic acid and butyl methacrylate corresponding to 1.5% by weight of calcium carbonate) was added. 70:30 copolymer, in which 20% of the total carboxyl groups of the acrylic acid moiety are ammonium salts), surface-treated under stirring, and then ethylene glycol was added.
The mixed system M ₃ of ethylene glycol and methanol and water and calcium carbonate were prepared. The mixed system was flushed using a rotary evaporator to remove methanol and water from the mixed system to prepare an anti-blocking agent ethylene glycol slurry. The residual ratio of water in the ethylene glycol was 0.5% by weight, and the solid concentration of calcium carbonate was 20.0% by weight. Table 2 shows the physical properties of the antiblocking agent in the ethylene glycol.

The same methanol as used in Example 6 Example 5 - quicklime - to prepare a mixed system M ₁ of water. After adjusting the mixed system M ₁ containing quicklime 200g to 42 ° C., to conduct the carbon dioxide gas into the stirring conditions the mixed system was started carbonation reaction. 13 minutes after the start of the carbonation reaction, the supply of carbon dioxide gas was stopped when the pH in the system reached 10.0. The stirring in the system was continued even after the supply of carbon dioxide gas was stopped, and the stirring was stopped at a pH of 9.7 in the system 20 minutes after the start of the carbonation reaction. Got _two . Further 16
The mixed system M ₁ is collected containing quicklime 200 g, methanol preform spherical vaterite type calcium carbonate described above the mixed system - was dropped into aqueous suspension D _2, carbonation allowed conducting carbon dioxide at the same time The reaction was performed. The dropping rate of the mixed system M ₁ every minute 0.833g as quicklime amount, the temperature is 41 ± 1 ° C. carbonation reaction system, pH in the carbonation system 8.8 ±
The carbonation reaction was carried out at 0.1 and the dropping carbonation reaction was terminated about 32 hours after the start of the dropping carbonation reaction. As a result of X-ray diffraction measurement, the calcium carbonate prepared in Example 6 was spherical calcium carbonate having a 100% vaterite structure.

[0047] The mixing system M ₂ of methanol and water and calcium carbonate prepared by the above method, the addition of surface treatment agent used in Example 5, ethylene glycol antiblocking agent in the same manner as in Example 5 below A slurry was prepared. Table 3 shows the physical properties of the antiblocking agent in the ethylene glycol.

The same methanol as used in Example 7 Example 5 - quicklime - to prepare a mixed system M ₁ of water. After adjusting the mixed system M ₁ containing quicklime 200g to 42 ° C., to conduct the carbon dioxide gas into the stirring conditions the mixed system was started carbonation reaction. Fifteen minutes after the start of the carbonation reaction, the supply of carbon dioxide was stopped when the pH in the system reached 9.2. After stopping the carbon dioxide supply is also continued agitation in the system, the stirring was stopped at pH in the system is 8.0, methanol preform spherical vaterite type calcium carbonate - to obtain an aqueous suspension D _2. Furthermore taken the mixed system M ₁ containing quicklime 800 g, methanol preform spherical vaterite type calcium carbonate described above the mixed system - was dropped into aqueous suspension D _2, carbonate brought into conduction carbon dioxide at the same time The reaction was carried out. Dropping rate of the mixed system M ₁ every minute 0.833g as quicklime amount, the temperature is 41 ± 1 ° C. carbonation reaction system, pH in the carbonation system controls the 9.8 ± 0.1 carbonate After about 16 hours from the start of the dropping carbonation reaction, the dropping carbonation reaction was terminated. As a result of X-ray diffraction measurement, the calcium carbonate prepared in Example 7 was spherical calcium carbonate having a 100% vaterite structure.

[0049] mixing system M ₂ of methanol and water and calcium carbonate prepared by the above method, the addition of surface treatment agent used in Example 5, ethylene glycol antiblocking agent in the same manner as in Example 5 below A slurry was prepared. Table 3 shows the physical properties of the antiblocking agent in the ethylene glycol.

The same methanol as used in Comparative Example 4 Example 5 - quicklime - to prepare a mixed system M ₁ of water. The mixed system M ₁ containing quicklime 200g collected, Example 5 matrix spherical vaterite type calcium carbonate prepared in a manner similar to methanol -
Was added dropwise to an aqueous suspension D _2, was carried out simultaneously carbonation reaction allowed conducting carbon dioxide. Dropping rate of the mixed system M ₁ every minute 0.833g as quicklime amount, the temperature is 37 ± 1 ° C. carbonation reaction system, pH in the carbonation system controls the 11.7 ± 0.1 carbonate About 24 hours from the start of the dropping carbonation reaction.
After 0 minute, the dropping carbonation reaction was completed. The calcium carbonate prepared according to Comparative Example 4 showed the result of X-ray diffraction measurement,
86% calcium carbonate having a vaterite structure,
It is a calcium carbonate having a large number of very fine calcium carbonates having a particle diameter of 0.1 μm or less and having uneven particle sizes, and a particle shape in which spherical, plate-like and elliptical spherical calcium carbonate are mixed. It was a homogeneous calcium carbonate.

[0051] The mixing system M ₂ of methanol and water and calcium carbonate prepared by the above method, the addition of surface treatment agent used in Example 5, ethylene glycol antiblocking agent in the same manner as in Example 5 below A slurry was prepared. Table 4 shows the physical properties of the antiblocking agent in the ethylene glycol.

[0052] Comparative Example 5 Example 5 In a manner analogous to that of the matrix spherical vaterite type calcium carbonate prepared in methanol - was further added water in the water mixing system M _2, quicklime converted value of the base material spherical vaterite type calcium carbonate , The amount of water is 35 times equivalent molar,
Methanol preform spherical vaterite type calcium carbonate - was prepared an aqueous suspension D _2. Further, methanol was further added to the same quick lime methanol suspension dispersion used in Example 5 to dilute the quick lime concentration to 3.0% by weight. And add
Methanol - quicklime - to prepare a mixed system M ₁ of water. 16
And recovering the mixed system M ₁ containing quicklime 200 g, to quick lime converted value of the base material spherical vaterite type calcium carbonate described above, the amount of water is present 35 times equivalent moles, of the base material spherical vaterite type calcium carbonate Methanol-water suspension D ₂
The carbonation was conducted under the same dropping carbonation conditions as in Example 6.
As a result of X-ray diffraction measurement, the calcium carbonate prepared in Comparative Example 5 was a calcium carbonate having a 65% vaterite structure, and was a calcium carbonate mixed with many large aggregates.

[0053] The mixing system M ₂ of methanol and water and calcium carbonate prepared by the above method, the addition of surface treatment agent used in Example 5, ethylene glycol antiblocking agent in the same manner as in Example 5 below A slurry was prepared. Table 4 shows the physical properties of the antiblocking agent in the ethylene glycol.

Comparative Example 6 Glycine and glutamic acid (both are a kind of amino acid) were added to lime milk having a specific gravity of 1.035 prepared by adding water to quicklime.
Was dissolved in calcium hydroxide in lime milk in an amount of 20% by weight, and then the lime milk was adjusted to 20 ° C., and then at a conduction rate of 0.822 liter / min per mole of calcium hydroxide in lime milk. Carbon dioxide gas was passed to perform a carbonation reaction, and the carbonation reaction was terminated at pH 6.5. As a result of X-ray diffraction measurement, the obtained calcium carbonate E was 100% vaterite-type calcium carbonate.

The surface treating agent used in Example 5 was added to the mixed system of water and calcium carbonate prepared by the above method, and an ethylene glycol slurry of an antiblocking agent was prepared in the same manner as in Example 5 below. . Table 4 shows the physical properties of the antiblocking agent in the ethylene glycol.

Comparative Example 7 A lime milk prepared by adding water to quick lime was mixed with a specific gravity of 1.07.
0, the temperature was adjusted to 10 ° C, and the concentration of carbon dioxide in the milk of lime was 2
5% by weight of furnace gas is supplied at a conduction speed of 20 m ³ / min,
A carbonation reaction was performed, and the carbonation reaction was completed at pH 6.5.
The liquid temperature of the aqueous calcium carbonate suspension after the completion of the carbonation reaction was adjusted to 70 ° C., and the mixture was stirred for 120 hours. The calcium carbonate thus prepared was calcite-type calcium carbonate, and the primary particle diameter in a scanning electron micrograph was 0.5 μm. The aqueous suspension of calcium carbonate was dehydrated according to a conventional method, and sodium polyacrylate was added to the obtained dehydrated cake in an amount of 1.5% by weight based on the solid content of calcium carbonate. 4
An aqueous slurry of 5% by weight of calcium carbonate was obtained. The water slurry was repeated 6 times at a flow rate of 60 cc / min using a wet pulverizer (Dynomill Pilot type, manufactured by WAB, media filling ratio 80%, media 0.6 to 0.9 mm, rotation speed 1).
(500 rpm) to carry out wet pulverization to disperse aggregates.

The surface treating agent used in Example 5 was added to the mixed system of water and calcium carbonate prepared by the above method, and an ethylene glycol slurry of an antiblocking agent was prepared in the same manner as in Example 5 below. . Table 4 shows the physical properties of the antiblocking agent in the ethylene glycol.

Application Example B Ethylene glycol slurry of the antiblocking agent prepared in Examples 4 to 6 and Comparative Examples 4 to 7 was added before the polyesterification reaction, and the polyesterification reaction was carried out. A polyethylene terephthalate having an intrinsic viscosity (orthochlorophenol, 35 ° C.) of 0.62 dl / g was prepared. The polyethylene terephthalate was dried at 160 ° C., melt-extruded at 290 ° C., and quenched and solidified on a casting drum maintained at 40 ° C. to obtain an unstretched film. Subsequently, the unstretched film was preheated to 70 ° C. with a heating roller, and then stretched 3.6 times in the longitudinal direction while heating with an infrared heater.
Subsequently, after stretching 4.0 times in the transverse direction at a temperature of 90 ° C.,
Heat treatment was performed at 00 ° C. to obtain a biaxially oriented film having a thickness of 15 μm.

The quality of the film thus obtained was evaluated by the following methods, and the results are shown in Tables 5 and 6. Film surface roughness (Ra) This is a value defined by JIS-B0601 as a center line average roughness (Ra). In the present invention, a stylus type surface roughness meter (SURFCORDER SF-30C) of Kosaka Laboratory Co., Ltd. is used. Measure using The measurement conditions and the like are as follows. (A) Probe tip radius: 2 μm (b) Measurement pressure: 30 mg (c) Cut-off: 0.25 mm (d) Measurement length: 0.5 mm (e) Repeat measurement for the same sample 5 times Except for one, it represents the average value of the remaining four data.

Coefficient of friction of film (μk) Measured as follows using the apparatus used in FIG.
In the figure, 1 is an unwinding reel, 2 is a tension controller, 3, 5, 6, 8, 9 and 11 are free rollers,
Is a tension detector (entrance), 7 is stainless steel mesh SUS
A 304 fixed rod (outer diameter 5 mm), 10 is a tension detector (outlet), 12 is a guide roller, and 13 is a take-up reel. In an environment of temperature 20 ° C and humidity 60%,
A film cut to a width of 1/2 inch is moved at a speed of 200 cm / min by contacting a fixing rod (surface roughness: 0.3 μm) of 7 with an angle θ = (152/180) π radian (152 °). (Friction). Outlet tension when the inlet tension T ₁ is to prepare a tension controller to a 35g (T _2: g) the film is detected by the outlet tension detector after traveling 90m, and calculates the running friction coefficient μk by: . μk = (2.303 / θ) log (T 2 / T 1) = 0.86log (T 2/35)

Evaluation of abrasion product-I A half-width film surface was brought into contact with a stainless steel fixing pin (surface roughness 0.58) having a diameter of 5 mm at an angle of 150 °,
About 15cm about reciprocated at a speed per minute 2m, frictionally (this time entry side tension T ₁ to 60 g). This operation is repeated, and the degree of scratches generated on the friction surface after the measurement of 40 reciprocations is visually determined in four stages based on the following criteria. ◎: Scratch scarcely generated 〇: Slight scratch generated △: Scratch considerably generated ×: Scratch generated many over the entire surface

Evaluation of abrasion product-II The sharpness of the running surface of the film is evaluated using a five-stage mini-super calender. The calender is a five-stage calender of nylon rolls and steel rolls. The processing temperature is 80 ° C, the linear pressure applied to the film is 200 kg / cm, and the film speed is 50 m / min. The running film is evaluated on the following four scales for the sharpness of the film due to the dirt adhering to the top roller of the calendar when the running film has traveled a total length of 4000 m. ：: Nylon roll dirt is not found at all 〇: Nylon roll dirt is hardly found ×: Nylon roll gets dirty XX: Nylon roll gets very dirty

Number of Coarse Protrusions on Film Surface After aluminum was thinly vapor-deposited on the film surface, the number of coarse protrusions (number per 1 mm ^{2 of the} measurement area) of a quadruple ring or more was counted using a ^two- beam interference microscope. Is represented by the following ranking. First grade: 16 or more Second grade: 12 to 15 Third grade: 8 to 11 Fourth grade: 4 to 7 Fifth grade: 0 to 3

[0064]

[Table 2]

[0065]

[Table 3]

[0066]

[Table 4]

[0067]

[Table 5]

[0068]

[Table 6]

[0069]

As described above, the anti-blocking agent for synthetic resins of the present invention exhibits good anti-blocking properties for synthetic resins, especially for synthetic resin films. It is an anti-blocking agent that can be used to prepare a film having good transparency without transparency. In the case of polyester film, slipperiness,
It is an anti-blocking agent which is excellent in abrasion resistance and can obtain a good film having few coarse projections.

[Brief description of the drawings]

FIG. 1 is a schematic view of an apparatus for measuring a dynamic friction coefficient (μk) of a film.

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shiro Genyoshi 1-126 Yamatedai, Okubo-cho, Akashi-shi, Hyogo (58) Field surveyed (Int. Cl. ⁷ , DB name) C08K 3/00-13/08 C08L 1/00-101/16

Claims (3)

(57) [Claims] 1. The following (A), (A), (C), (D),
(E) antiblocking agent for synthetic resin consisting of calcium carbonate which satisfies both requirements (a); (a) 0.1 μm ≦ DS1 ≦ 10 μm (a) 0.033 μm ≦ DS2 ≦ 10 μm (c) DP3 / DS1 ≤1.25 (d) 1.0≤DP2 / DP4≤2.5 (e) 1.0≤DP1 / DP5≤4.0 (f) (DP2-DP4) /DP3≤1.0, where DS1: Average particle diameter of major axis of primary particles (μm) examined by scanning electron microscope (SEM) DS2: Average particle diameter of minor axis of primary particles examined by the microscope (μm) DP1: Light transmission type particle size distribution measurement Machine (SA- manufactured by Shimadzu Corporation)
In the particle size distribution measured using CP3), the particle size (μ
m) DP2: In the particle size distribution measured using the above measuring device, the particle size (μm) at 25% of the cumulative weight calculated from the larger particle diameter side DP3: In the particle size distribution measured using the above measuring device, Particle size at 50% cumulative weight calculated from particle size side (μm) DP4: Particle size at 75% cumulative weight calculated from large particle size side (μm) DP5: particle size (μm) at a cumulative weight of 90% calculated from the larger particle size side in the particle size distribution measured using the above measuring instrument. 2. The anti-blocking agent for synthetic resins according to claim 1, wherein DS1 / DS2 is calcium carbonate having the following range: 1 ≦ DS1 / DS2 ≦ 3. 3. The antiblocking agent for a synthetic resin according to claim 1, wherein the synthetic resin is used for a synthetic resin film.