JP2017078124A - Antiblocking agent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antiblocking agent that can exhibit sufficient antiblocking performance when used for a stretched film.SOLUTION: There is provided an antiblocking agent composed of surface-treated silica-alumina amorphous particles, comprising aminoalkylalkoxysilane as a surface treatment agent component, and a median diameter (D) in terms of volume, measured by Coulter counter method, of 1.9-25.0 μm.SELECTED DRAWING: None

Description

  The present invention relates to an antiblocking agent, and more particularly to an antiblocking agent used particularly for stretched films.

Generally, an anti-blocking agent (AB agent) is blended in a plastic film because it has a property that when the films are overlapped, the films are in close contact with each other and are not easily peeled off (easy to block). Due to the blending of the AB agent, the adhered films are easily peeled off.
As for the plastic film, it is known that various physical properties such as strength are improved by the stretching operation, and the stretched plastic film is widely used for applications such as food packaging. AB agent is mix | blended also with such a stretched film.

  As the AB agent, amorphous silica / alumina spherical particles are known. For example, Patent Document 1 proposes to use ion-exchanged zeolite (amorphous zeolite) obtained by calcination after ion-exchange of P-type zeolite with a divalent metal such as calcium as an AB agent. Yes.

  By the way, when a film formed from a resin composition containing an AB agent is subjected to a stretching operation, there is a problem that voids (peeling of the AB agent from the matrix resin) occur. For this reason, as the AB agent for the stretched film, among the above amorphous silica / alumina-based spherical particles, those having a small particle size are used (average particle size is about 1.8 μm). This is because when the film is stretched, voids are more likely to occur as the larger particles are blended.

  However, since particles having a small particle size are likely to aggregate, it is difficult to uniformly disperse when blended in a resin, and the performance such as anti-blocking property and transparency is likely to vary, which is larger than that having a small particle size. The one is preferred. Furthermore, regarding anti-blocking properties, anti-blocking agents composed of conventionally known amorphous silica / alumina-based spherical particles having a small particle size are blended in an unstretched film or blended in a stretched film. However, the anti-blocking performance is insufficient.

  In addition, depending on the size of the generated void, the anti-blocking agent particles may drop off in the winding process after stretching, causing problems such as contamination of the machine or film.

JP-A-2-225314

  Accordingly, an object of the present invention is to provide an antiblocking agent that can exhibit sufficient antiblocking performance when used in a stretched film.

  The present inventors have intensively studied the anti-blocking agent used in the stretched film, and the silica-alumina amorphous particles surface-treated with aminoalkylalkoxysilane are stretch-molded even if the particle size is large. As a result, the inventors have found a very unexpected fact that the generation of voids can be effectively suppressed to the same degree or more than that having a small particle diameter, and the present invention has been completed based on such fact.

According to the present invention, the surface-treated silica / alumina amorphous particles are used, the aminoalkylalkoxysilane is contained as a surface treating agent component, and the volume-based median diameter (D ₅₀ ) measured by the Coulter counter method is 1. The antiblocking agent characterized by being 9-25.0 micrometers is provided.

  The antiblocking agent of the present invention preferably contains the aminoalkylalkoxysilane in an amount of 0.1 to 4.0% by mass. Moreover, it is preferable that the antiblocking agent of this invention is used for stretched films, and it is more preferable that this stretched film is a stretched polyolefin film.

  The surface-treated silica / alumina amorphous particles used as the anti-blocking agent of the present invention have a particle size in the range of 1.9 to 25.0 μm, and the particle size of AB agent used in conventional stretched film applications Bigger than that. Nevertheless, as shown in Examples described later, in the stretched film obtained from the resin composition using the anti-blocking agent of the present invention, generation of voids is effectively suppressed. Moreover, since this stretched film has a large particle size of the blended antiblocking agent, it is naturally excellent in antiblocking performance.

It is a figure of AB agent peeling evaluation (number of voids) from a stretched film.

  The surface-treated silica / alumina amorphous particles of the present invention are obtained by surface-treating silica / alumina amorphous particles with an aminoalkylalkoxysilane, and the particle diameter thereof is relatively large at 1.9 to 25.0 μm. It is characterized by a point.

<Surface treatment agent (aminoalkylalkoxysilane)>
Aminoalkylalkoxysilane (hereinafter sometimes abbreviated simply as aminosilane) can be obtained at a lower cost than conventionally known silane coupling agents such as methacrylic silane, and each of antiblocking properties, transparency, slipping properties, etc. The performance can be improved and is represented by the following formula (1).
_Xn- Si (R) _m (OR) _4-nm (1)
Where
n is an integer of 1 to 3,
m is an integer from 0 to 2,
R is a methyl group, an ethyl group or an isopropyl group;
X is an aminoalkyl group, and the amino group may have a substituent such as an alkyl group or a phenyl group, and the substituent may further have an amino group,
When a plurality of X and R are present, the plurality of X and R may be different from each other.

  Specific examples of aminosilane include N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N- (1 , 3-dimethyl-butylidene) propylamine, N-phenyl-3-aminopropyltrimethoxysilane, hydrochloride of N- (vinylbenzyl) -2-aminoethyl-3-aminopropyltrimethoxysilane, and the like. Among these, 3-aminopropyltriethoxysilane (γ-aminopropyltriethoxysilane) is particularly preferable.

  In the present invention, the silica / alumina amorphous particles are surface-treated with the above-mentioned aminosilane, and the treatment amount is 0.1 to 4 per 100 parts by mass of untreated silica / alumina amorphous particles. It is preferable to set it as 2 mass parts, and it is more preferable to set it as 0.2-3.0 mass parts. In the surface-treated silica / alumina amorphous particles thus obtained, the content of unreacted silane is suppressed to 3 mg / kg or less. If the surface treatment amount is too small, uniform dispersion is difficult when the obtained surface-treated silica / alumina amorphous particles are dispersed in the resin, and the expression of each performance such as anti-blocking property may become unstable. There is. If the amount of surface treatment is too large, the particles tend to aggregate and the expression of various performances may become unstable. In addition, it may be difficult to adjust the particle size to a certain range (1.9 to 25.0 μm).

  The surface treatment using aminosilane can be easily performed using a known method such as a dry method, a slurry method, a spray method, etc., but in order to suppress the amount of unreacted silane, It is preferable to perform processing. The dry method can be easily performed, for example, by mixing untreated amorphous silica and a predetermined amount of aminosilane under heating at about 100 to 150 ° C. using a dry mixer such as a super mixer. The end point of the reaction can be confirmed by stopping the production of alcohol vapor such as ethanol. The generation of alcohol vapor is recognized when the surface of a watch glass or the like is clouded.

<Silica / alumina amorphous particles>
In the present invention, as the silica / alumina amorphous particles to be surface-treated (untreated silica / alumina amorphous particles), any known one can be used without particular limitation as long as it can exhibit anti-blocking properties. Can do.

The size of the untreated silica / alumina amorphous particles is appropriately selected so that the particle diameter of the finally obtained surface-treated silica / alumina amorphous particles falls within the range described later (1.9 to 25.0 μm). Generally, it is preferable that the volume-based median diameter (D ₅₀ ) measured by the Coulter counter method is a particle diameter of 1.9 to 20.0 μm.

  As described above, as the untreated silica / alumina amorphous particles, known particles can be used without any limitation, but the hygroscopicity is suppressed by amorphization due to the viewpoint of developing sufficient anti-blocking properties. In view of the above, amorphous particles obtained by ion-exchange and calcination of P-type zeolite (hereinafter sometimes referred to as “P-type zeolite amorphous particles”) are optimal.

P-type zeolite has a characteristic X-ray diffraction image, and individual particles as a whole have a well-defined spherical shape and a pear-like surface. P-type zeolite is mixed with sodium silicate or activated silicate gel, silica sol, metakaolin, sodium aluminate, alumina sol and sodium hydroxide so as to satisfy the following blending conditions to form an alkali aluminosilicate gel, After this gel is homogenized, it is produced by crystallization at a temperature of 80 to 200 degrees under normal pressure or hydrothermal conditions.
Compounding conditions (molar ratio)
Na ₂ O / SiO ₂ : 0.2 to 8 (preferably 0.5 to 1.0)
_{SiO 2 / Al 2 O 3:} 3~20 ( preferably 3.5-6)
H ₂ O / Na ₂ O: 20 to 200 (preferably 30 to 120)

An example of the chemical composition of the produced P-type zeolite is as follows.
_{kNa 2 O · pSiO 2 · Al} 2 O 3 · q'H 2 O
Where
k is a number of 1.1 ± 0.2, p is a number of 4 ± 1.5, and q ′ is a number of 1.0 or less.

  The P-type zeolite is washed with water and further subjected to a classification operation to a predetermined particle size, and then subjected to the next ion exchange treatment step. As the divalent metal used for ion exchange, Ca, Mg, Zn, Ba or Sr, which is a Group II metal of the periodic table, is advantageously used in terms of whiteness, but in addition, Cu, Sn, Fe Other metals such as Ni, Cr, etc. can also be used. Ion exchange is performed by using a water-soluble salt of these metals, for example, an aqueous solution of chloride, nitrate, sulfate, etc., and bringing the metal salt solution into contact with P-type zeolite. For the ion exchange treatment, a method in which the metal salt aqueous solution and the P-type zeolite are stirred in an aqueous slurry state, or a method in which the P-type zeolite is brought into contact with the metal salt aqueous solution in a fixed bed or a fluidized bed is employed. This contact can be performed in a single-stage or multi-stage system, and can be carried out continuously or batchwise.

The ion exchange conditions are such that at least 10 mol% or more, particularly 30 mol% or more of the Na ₂ O content in the P-type zeolite is replaced with MO (M is a divalent metal). For this purpose, in the metal salt solution in the treatment system, a metal salt of 0.5 mol times or more, particularly 0.8 mol times or more per Na ₂ O content in the P-type zeolite is used. P-type zeolite is generally preferably brought into contact with an aqueous salt solution having an initial concentration of 10 to 40% by weight, particularly 20 to 50% by weight. The temperature at the time of contact is preferably in the range of 20 to 100 ° C., particularly 30 to 70 ° C. As a matter of course, the exchange treatment is shortened at a higher temperature. Although the contact time varies depending on the temperature and the exchange rate, it is preferably 0.5 to 3 hours.

After contacting the metal salt solution and the P-type zeolite as described above, the obtained ion-exchanged P-type zeolite is subjected to solid-liquid separation, washed with water, dried or crushed as necessary, and the next firing step. I do.
In the calcining step, the P-type zeolite after ion exchange is calcined. The firing conditions may be set to such an extent that the ion-exchanged P-type zeolite becomes substantially amorphous. Specifically, although the firing temperature varies depending on the exchange rate and the metal species, 450 to 850 ° C., particularly 600 to 800 ° C. is preferable from the viewpoint of more efficiently transporting moisture and improving productivity. Firing for amorphization can be performed in a fixed bed, a moving bed, or a fluidized bed. A treatment time of 0.5 to 5 hours is sufficient.

  By pulverizing or pulverizing the calcined P-type zeolite and classifying it as necessary, P-type zeolite amorphous particles optimum as a raw material can be obtained. The characteristics of the P-type zeolite amorphous particles are as disclosed in Patent Document 1, that is, the entire particles have a spherical shape, the surface is jagged, and exhibits low hygroscopicity.

Since untreated silica / alumina amorphous particles such as P-type zeolite amorphous particles are subjected to the above-mentioned surface treatment with aminosilane, the anti-blocking agent (surface-treated silica / alumina amorphous particles) of the present invention is used. However, it is preferable that the volume-based median diameter (D ₅₀ ) measured by the Coulter counter method is 1.9 to 20.0 μm, and is 2.0 to 8.0 μm immediately before the surface treatment. Is more preferable and it is still more preferable that it exists in the range of 2.0-5.3 micrometers. If the particle size of the untreated silica / alumina amorphous particles immediately before the surface treatment is in the above range, even if the particle size is increased by the surface treatment, it is within the numerical range (1.9 to 25.0 μm) described later. This is because surface-treated silica / alumina amorphous particles having a particle diameter can be obtained.

<Anti-blocking agent>
The AB agent (surface-treated silica / alumina amorphous particles) of the present invention obtained as described above has a volume-based median diameter (D ₅₀ ) of 1.9 to 25.0 μm as measured by the Coulter counter method. It is in the range. When the particle diameter of the surface-treated silica / alumina amorphous particles is within such a range, the particles can be prevented from agglomerating, so that generation of voids in the stretched film is effectively suppressed. Furthermore, due to the large particle size, the surface-treated silica / alumina amorphous particles in the present invention can effectively exhibit each performance such as anti-blocking property. Furthermore, if the particle diameter of the surface-treated silica / alumina amorphous particles is too large, the scratch resistance tends to be impaired, but if it is within the above range, there is also an advantage that good scratch resistance can be obtained.

  As confirmed in the examples described later, since the above-mentioned effect tends to become more prominent as the particle size is larger, the particle size of the surface-treated silica / alumina amorphous particles is 1.9 to 25. It is preferably in the range of 0 μm, particularly preferably in the range of 2.0 to 8.0 μm, and further preferably in the range of 2.0 to 5.5 μm.

The antiblocking agent of the present invention preferably contains 0.1-4.0% by mass of the above-mentioned aminosilane as a surface treatment agent, and more preferably 0.2-3.0% by mass. When the amount of aminosilane is too small, it means that the surface treatment is insufficient, so when dispersed in a resin as an antiblocking agent, uniform dispersion becomes difficult, and each performance such as antiblocking properties is improved. Expression may be unstable. If the amount of aminosilane is too large, it means that the surface treatment is excessive, so that the particles tend to aggregate and the expression of various performances may become unstable.
In the antiblocking agent of the present invention, the content of unreacted silane is suppressed to 3 mg / kg or less. For this reason, the influence of the surface treatment agent (aminoalkylacoxysilane) on the environment can be ignored. Therefore, the film in which the antiblocking agent is blended is not limited in use, for example, as a food packaging material. There is also an advantage that it can be used without any limitation in use.

  The anti-blocking agent of the present invention having such characteristics is used for preparing a resin composition, and various articles such as a film are formed from the obtained resin composition. When the final molded product is a film, such a film can be widely applied to known uses.

  The resin composition may be prepared by a conventionally known method. For example, the anti-blocking agent of the present invention may be directly mixed in the molten base resin, or the anti-blocking agent of the present invention may be mixed in the base resin. A master batch blended with the above may be prepared, and this master batch may be further blended with the base resin (that is, diluted with the base resin).

  As the base resin, a conventionally known resin used for forming a film, such as a thermoplastic resin, can be used without any limitation. Examples of the thermoplastic resin include polyolefin resins such as polypropylene, polyethylene, crystalline polypropylene-ethylene copolymer, ion-crosslinked olefin copolymer, and ethylene-vinyl acetate copolymer; thermoplastics such as polyethylene terephthalate and polybutylene terephthalate. Polyesters; polyamides such as 6-nylon and 6,6-nylon; chlorine-containing resins such as vinyl chloride resins and vinylidene chloride resins; polycarbonates; polysulfones; polyacetals and the like. Therefore, from the viewpoint that the effects of the present invention can be maximized, polyolefin resin is preferable, and polypropylene is particularly preferable.

  The amount of the antiblocking agent used in the resin composition may be appropriately determined according to the type of the final molded product, etc., but is generally 0.01 to 5 parts by mass, especially 0, per 100 parts by mass of the resin composition. 0.05 to 0.6 parts by mass.

  When the final molded product is a film, the anti-blocking agent of the present invention is melted and mixed with the base resin directly or in a masterbatch state, and the resulting resin composition is used to form a film according to the application. The target film can be obtained. Melt mixing may be performed by a method known per se, for example, a Henschel mixer, a super mixer, a Banbury mixer, a ribbon blender, a single-screw or twin-screw extruder, a roll or the like, or a kneader. The film may be formed by a method known per se. For example, the resin composition may be melt-kneaded with an extruder, extruded through a die, and formed by an inflation film forming method, a T-die method, or the like.

  The film may contain various additives known per se, such as antioxidants, colorants, lubricants, etc., and such additives can be added to the masterbatch. Also, it can be blended with a base resin for dilution at the time of film formation.

Such a film is preferably uniaxially or biaxially stretched, and particularly preferably biaxially stretched, from the viewpoint that the effects of the present invention can be maximized. Further, the draw ratio can be arbitrarily changed depending on the required film properties. In general, voids are likely to occur when severe stretching is performed, and thus the effect of the present invention that effectively suppresses the generation of voids is remarkably exhibited. For example, as shown in an experimental example to be described later, the number of voids in the case where the film of the present invention is biaxially stretched 6 × 6 times is 22 to 62 / mm ² , which corresponds to the film observation area. Since the void area ratio is 0.10 to 0.30%, the void area ratio is remarkably small as compared with the case where the surface-treated silica / alumina amorphous particles having a small particle diameter are blended.

  The film may have a single-layer structure, but as long as the effects of the present invention are not impaired, at least one surface is formed from a resin composition in which the AB agent of the present invention is blended. A laminated structure having

  The invention is further illustrated by the following experimental examples. Various physical properties were measured by the following methods.

(1) Content analysis of unreacted silane About 3 g of sample was extracted by stirring with 30 mL of dichloromethane for 5 hours. The extract was subjected to gas chromatograph / mass spectrometry (GC / MS) measurement under the following conditions to quantify the residual amount (content) of extractable unreacted silane. In addition, although a unit is a mg / kg filler, it describes with mg / kg in the specification.
GC / MS analysis conditions Equipment: TRACE DSQ manufactured by Thermo Scientific
Column: Rtx-5Amine (30 m × 0.25 mm × 0.25 μm)
Injection mode: Split (split ratio 10: 1)
Column flow rate: 1.0 mL / min
GC temperature condition Inlet: 250 ° C
Temperature rising conditions: 50 ° C to 280 ° C
MS interface: 280 ° C
MS condition Ion source temperature: 250 ° C
Ionization voltage: 70 eV
Measurement mode: SIM
Quantitative ion: 163 m / z

(2) Bulk density JIS. K. Measurement was performed according to 6220-1 7.7: 2001.

(3) Median diameter (D ₅₀ )
Weigh 0.5 g of sample in a 200 ml beaker, add 150 ml of deionized water to this, and stir, and in Examples 1, 2, 4 and 5, ultrasonically disperse for 2 minutes, and in Examples 3 and 6 ultrasonically. Dispersed for 3 minutes. The dispersion was measured for volume-based median diameter (D ₅₀ ) using a Coulter counter (Beckman Coulter Multisizer 3) aperture tube 50 μm.

(4) Oil absorption JIS. K. It was measured according to 5101-13-1: 2004.

(5) Moisture JIS. K. Referring to 5101-15-1: 2004, a weight loss of 250 ° C. × 2 hours was measured.

(Comparative Example 1)
Example 4 Sample No. 4 of JP-A-2-225314. Amorphous silica / alumina-based spherical particles A having a volume-based median diameter (D ₅₀ ) of 1.8 μm obtained by the method described in 4-1.

(Comparative Example 2)
3.0 kg of amorphous silica / alumina-based spherical particles A on a dry basis at 110 ° C. were added to a super mixer SMV-20 manufactured by Kawata Corporation and stirred. During stirring, 90 g of 3-aminopropyltriethoxysilane (surface treatment agent A) as a silane coupling agent was dropped and heated to 140 ° C. When the watch glass was held over the exhaust port, the mixture was stirred with ethanol, which is a volatile component, until it did not become cloudy to obtain surface-treated amorphous silica / alumina spherical particles A-30.

(Comparative Example 3)
Reference is made to the method described in the example of JP-A-2-225314, and comprises P-type zeolite amorphous particles having a volume-based median diameter (D ₅₀ ) of 2.1 μm and obtained at a firing temperature of 700 ° C. Silica-alumina amorphous particles B were used.

(Comparative Example 4)
Reference is made to the method described in the Example of JP-A-2-225314, and comprises P-type zeolite amorphous particles obtained at a calcination temperature of 750 ° C. and having a volume-based median diameter (D ₅₀ ) of 2.9 μm. Silica-alumina amorphous particles C were used.

Example 1
Surface-treated silica / alumina non-spherical particles A were changed in the same manner as in Comparative Example 2 except that the amorphous silica / alumina-based spherical particles A were changed to silica / alumina amorphous particles B and the amount of the surface treatment agent A was changed to 15 g. Crystalline particles B-05 were obtained.

(Example 2)
Surface-treated silica / alumina amorphous particles B-20 were obtained in the same manner as in Example 1 except that the amount of the surface treatment agent A was changed to 60 g.

(Example 3)
Surface-treated silica / alumina amorphous particles B-30 were obtained in the same manner as in Example 1 except that the amount of the surface treatment agent A was changed to 90 g.

Example 4
Surface-treated silica / alumina non-crystalline silica / alumina non-spherical particles A were prepared in the same manner as in Comparative Example 2 except that the amount of the surface-treating agent A was changed to 15 g. Crystalline particles C-05 were obtained.

(Example 5)
Surface-treated silica / alumina amorphous particles C-30 were obtained in the same manner as in Example 4 except that the amount of the surface treatment agent A was changed to 90 g.

  Physical properties of the obtained particles were measured, and the results are shown in Table 1.

<Evaluation as an anti-blocking agent (AB agent)>
Each AB agent is added so that it may become 2 mass parts per 100 mass parts of polypropylene resin (random PP, MFR = 7g / 10min), it melts and mixes at 230 degreeC using a twin-screw extruder (phi 26mm), and total extrusion Extrusion was performed at an amount of 2.7 kg / hr to obtain a master batch (MB). In addition, components other than AB agent are not added.

  In this master batch, the polypropylene resin is melt-mixed so that the blending amount of the anti-blocking agent per 100 parts by mass of polypropylene is 0.2 parts by mass, and the thickness is 370 to 390 μm using a T-die film manufacturing apparatus. PP sheet was prepared. Next, the film was stretched simultaneously at a stretching speed of 26 m / min and a stretching temperature of 127 ° C. using a biaxial stretching apparatus EX-10B manufactured by Toyo Seiki Co., Ltd., with a length × width = 6 × 6 times. Produced. The following evaluation was performed about the produced BOPP film. The evaluation results are shown in Table 2.

(6) Blocking force The blocking force of the film was measured by a method based on ISO 11502-1995 method B. The thermocompression bonding conditions between the films were 6 kgf / 100 cm ² , 60 ° C., and 3 days. As a measuring device, an autograph AGSH20N manufactured by Shimadzu Corporation was used.

(7) Evaluation of number of voids and void area ratio A film surface shape having an observation range of 630 μm × 470 μm was observed using a surface roughness meter VertScan 2.0 manufactured by Ryoka System. Based on a smooth surface having no irregularities, a recess having a depth of 0.25 μm or more and an area of 5 μm ² or more on the smooth surface is defined as a void, the number (pieces / mm ² ) and the void area ratio to the observation area (% ) Was measured.

(8) Evaluation of scratch resistance The films prepared using the Toyo Seiki friction measuring machine TR-2 were rubbed together to measure the haze before and after the scratch, and the difference ΔHaze was used as an index of scratch resistance. . The smaller the ΔHaze, the better the scratch resistance.

  The evaluation results of the BOPP film are shown in Table 2.

Claims (4)

It consists of amorphous particles of surface-treated silica / alumina, contains aminoalkylalkoxysilane as a surface treating agent component, and has a volume-based median diameter (D ₅₀ ) of 1.9 to 25.0 μm as measured by a Coulter counter method. An anti-blocking agent characterized by   The antiblocking agent of Claim 1 which contains the said aminoalkyl alkoxysilane in the quantity of 0.1-4.0 mass%.   The antiblocking agent of Claim 1 or 2 used for stretched films.   The antiblocking agent according to claim 3, wherein the stretched film is a stretched polyolefin film.