JP2003026866A - Additive for polyolefin resin sheet and resin composition for the sheet compounded with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inorganic additive for a polyolefin resin sheet exhibiting good workability when the sheet is produced, by adding capable of making the sheet have an antiblocking effect, and capable of giving excellent moisture absorbability. SOLUTION: This additive for the olefinic resin sheet comprises calcium carbonate powder of which the particle size distribution satisfies the following requisites (1) to (3): (1) 2<=A<=30 [A is an average particle diameter (μm) of the calcium carbonate powder and corresponds to a 50% particle diameter (d50) through which 50% of particles of the calcium carbonate powder pass when measured by a particle size distribution analyzer of Microtrack FRA laser type]; (2) 1<=B<=25 [B is a sharpness coefficient and expressed by (d90)/(d10); (d90) is a 90% cumulative undersize diameter (μm) through which 90% of the particles cumulatively pass when measured by the analyzer; and (d10) is a 10% cumulative undersize diameter (μm) through which 10% of the particles cumulatively pass]; and (3) 0<=C<=25 [C is a cumulative undersize weight percent (%) of the particles which pass through a sieve mesh corresponding to a halt of the average particle diameter (A)].

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an olefin resin sheet additive made of a specific calcium carbonate and a resin composition for a sheet containing the same, and the purpose thereof is that calcium carbonate is a resin. Providing a polyolefin porous resin sheet having properties suitable for a resin sheet due to being well dispersed therein, for example, excellent blocking resistance, or effective moisture permeability, and water absorption, and the sheet. It is to improve the workability during the production of the resin composition for use, for example, to prevent the fluctuation of the resin pressure and the generation of the partially deteriorated resin, which are likely to occur during the kneading and extrusion.

[0002]

2. Description of the Related Art Polyolefin resins used for polyolefin resin sheets include crystalline non-elastomeric polyolefin resins such as low density polyethylene, medium density polyethylene, high density polyethylene, polypropylene, polymethylpentene, polybutene, ethylene-propylene. Copolymers, propylene-butene copolymers, and amorphous olefinic thermoplastic elastomers, for example, thermoplastic elastomers composed of ethylene-propylene-butene random copolymer resins, olefins composed of ethylene-styrene-butylene copolymers. There are thermoplastic elastomers, etc., which are used for various purposes.

The purpose of incorporating an inorganic filler into these resin sheets is also to impart anti-blocking properties and thermal stability, or to provide effective moisture permeability, porosity for water absorption, and coloring properties. Although there are various properties such as application, the most important property common to the fillers is the dispersibility in the resin to be blended. Among them, as the inorganic filler made of calcium carbonate, various grades are mass-produced, the quality is stable, and it is relatively inexpensive,
Furthermore, it is widely used because of its low wear of a kneader, extruder, molding machine and the like.

In order for a resin product containing an inorganic filler such as calcium carbonate to exhibit desired performance, the inorganic filler must be dispersed in the resin in a necessary and sufficient amount. For this reason, various improvements to the kneading machine and the kneading conditions, while various improvements have been made, various surface treatment agents and surface treatment methods have been investigated in order to improve the dispersibility in the resin even on the inorganic filler side. The situation is not yet sufficient in terms of dispersibility into

For example, a porous sheet produced by a method in which a synthetic resin is formed into a sheet and further stretched to form a void at the interface between the resin and the filler by utilizing the difference in mechanical properties between the resin and the inorganic filler, , Synthetic paper, sanitary materials, medical materials, building materials, air-permeable sheets for agriculture, battery separators, etc.
Although it has been partially put into practical use, there is still room for improvement to become a product with sufficient performance.

[0006] In addition, an inorganic filler is blended in a POP poster or a decorative sheet made of a polyolefin-based sheet for the purpose of imparting dimensional stability, printability, slipping property and blocking resistance. If it is left as an agglomerate, the appearance and performance of the sheet will be finally impaired, and the strength of the agglomerate part will be low, and it will be easily damaged in the subsequent sheet processing step. Therefore, it is necessary to cut the defective portion by hand or by some method and remove it from the product.

As described above, it is extremely important to uniformly disperse the inorganic filler in the resin. However, if the dispersion depends only on mechanical force, the production cost will increase and the resin will be dispersed even if it can be dispersed to some extent. There is a risk that the work environment may deteriorate due to deterioration and generation of gas and dust due to resin decomposition. In addition, when a resin and an inorganic filler are stirred and mixed for a long time using a Henschel type mixer in a preblender, even if the jacket is cooled, the surface treatment agent added to the resin or the filler can be applied to the wall and stirring blades inside the mixer. The filler scorches and peels off to form an agglomerate, which is mixed in the kneading and extrusion step and causes the strainer attached inside the die of the extruder to be clogged. In film applications, a strainer with a fine mesh is used, so clogging is particularly likely to occur. Replacing the strainer not only requires manpower, but also causes a great increase in cost such as loss of resin and loss of time.

Inorganic fillers include coupling agents, higher fatty acids, salts thereof, in order to improve the dispersibility thereof.
Surface treatment agents such as esters have been investigated. However, although the surface-treated products that have been proposed so far have been evaluated to some extent for specific applications, it is generally difficult to say that they exhibit sufficiently satisfactory dispersibility.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide a calcium carbonate filler which is blended with an olefin resin and retains excellent dispersibility. By using the filler, the above-mentioned problems are solved, and for example, the workability of mixing and kneading the filler and the resin and the sheeting is improved, and the synthetic resin composition becomes a sheet having very few visually dimensional defects. To provide things.

[0010]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a polyolefin resin composition containing calcium carbonate having a specific particle diameter and a specific particle size content is blended. The inventors have found that they have an initial purpose, and have completed the present invention.

That is, the present invention provides an olefin resin sheet additive characterized by comprising calcium carbonate powder satisfying the particle size distribution constitutions of the following formulas (1), (2) and (3). (Claim 1). 2 ≦ A ≦ 30 (1) 1 ≦ B ≦ 25 where B = d90 / d10 (2) 0 ≦ C ≦ 25 (3) where A: average of calcium carbonate powder 50% of particle diameter (μm) measured by Microtrac FRA laser particle size distribution meter (d50) B: Sharpness coefficient of calcium carbonate powder d90: Particle measured by Microtrac FRA laser particle size distribution meter Sieve passing side cumulative 90% diameter (μm) d10: Sieve passing side cumulative 10% diameter (μm) of particles measured by Microtrac FRA laser particle size distribution meter C: A measured by Microtrac FRA laser type particle size distribution meter / 2 particle size sieve pass side cumulative percentage (%).

A preferred embodiment is the olefin resin sheet additive according to claim 1, which further comprises heavy calcium carbonate further satisfying the following formula (4) (claim 2). D ≦ 100 (4) D: Maximum particle diameter (μm) measured by Microtrac FRA laser type particle size distribution meter.

In a preferred embodiment, the olefin resin sheet additive according to claim 1 or 2 is composed of heavy calcium carbonate which further satisfies the following formula (5) (claim 3). 1 ≦ E ≦ 3 However, E = d75 / d25 (5) d75: Microtrack FRA laser type cumulative 75% diameter (μm) of particles passing through sieve measured by particle size distribution meter d25: Microtrack FRA laser type Cumulative 25% diameter (μm) of particles passing through a sieve measured by a particle size distribution meter.

[0014] As a preferred mode, the additive for olefinic resin sheet according to any one of claims 1 to 3, which is composed of heavy calcium carbonate having a constant pressure aeration type powder specific surface area Sw of 15000 cm ² / g or less. It is an agent (claim 4).

A second aspect of the present invention comprises an olefin sheet resin composition containing the olefin resin sheet additive according to any one of claims 1 to 4 (claim 5). ).

As a preferred mode, the olefin resin sheet resin composition according to claim 5, wherein the addition amount of the olefin resin sheet additive is 10 to 150 parts by weight relative to 100 parts by weight of the olefin resin. Item 6).

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The calcium carbonate powder constituting the additive for an olefin resin sheet of the present invention has an average particle size A of the following formula (1), preferably the following formula (6), more preferably the following formula: It is necessary to select calcium carbonate so as to satisfy (7).

2 ≦ A ≦ 30 (1) 3 ≦ A ≦ 20 (6) 5 ≦ A ≦ 16 (7) where A: average particle diameter of the calcium carbonate powder (μm ), 50% particle diameter (d50) of particles measured by Microtrac FRA laser type particle size distribution diameter

That is, the average particle diameter A of calcium carbonate
When the particle size exceeds 30 μm, fine particles are frequently generated due to a kneading operation with the resin, which may cause clogging of the strainer.
It causes secondary aggregates in the resin sheet. On the other hand, when the average particle diameter A of calcium carbonate is smaller than 2 μm, the dispersibility in the resin deteriorates, resulting in clogging of the strainer and secondary aggregates in the resin sheet.

The sharpness coefficient B of calcium carbonate also affects the dispersibility in the resin. In the present invention, the sharpness coefficient B of calcium carbonate is the following formula (2), preferably the following formula (8), and more preferably the following formula (9).
Must be selected so that

1 ≦ B ≦ 25 (2) 1 ≦ B ≦ 20 (8) 1 ≦ B ≦ 15 (9) where B = d90 / d10 B: calcium carbonate powder Sharpness coefficient d90: 90% diameter (μm) of cumulative particles passing through the sieve measured by Microtrac FRA laser particle size distribution meter (μm) d10: 10% diameter of cumulative particles passing through the sieve measured by Microtrac FRA laser particle size distribution meter (μm) (μm) μm)

That is, d90 (90% particle size of powder)
And the d10 (10% particle diameter of the powder) are smaller, the particle size distribution becomes more uniform and the dispersibility in the resin is improved. Therefore, when the sharpness coefficient B exceeds 25, the particle size distribution becomes broad (a mixture of coarse particles and fine particles), and fine particles are aggregated or adhered to the coarse particles, resulting in extremely poor dispersion. As B approaches 1, the particle composition becomes more uniform and the dispersibility is improved. When B is less than 1, it is impossible due to the nature of the formula.

Further, in the particle size distribution constitution of calcium carbonate, the abundance ratio of the fine powder affects the dispersibility. In the present invention, it is necessary to select such that the accumulation of 1/2 particle diameter (= A / 2 particle diameter) satisfies the following expression (3). The following formula (10) is preferable, and the following formula (11) is more preferable.
Is selected so that

0 ≦ C ≦ 25 (3) 0 ≦ C ≦ 20 (10) 0 ≦ C ≦ 15 (11) where C: measured by Microtrac FRA laser particle size distribution meter Sieve passing side cumulative percentage (%) of the obtained A / 2 particle size.

The smaller the accumulation of ½ average particle size or less, the sharper the particle size distribution constitution is, and the excellent dispersibility is exhibited. Further, since the filler can be blended in a high number of parts, the blending design becomes easy in the case of the polyolefin-based porous sheet. When the cumulative percentage C of ½ average particle size or less exceeds 25 or more, it is difficult to disperse the resin in the resin because of the large amount of fine particles, and secondary aggregates frequently occur in the sheet.

Furthermore, the presence of the maximum particle size not only affects the appearance and characteristics of the olefin resin sheet, but also tends to cause clogging of the strainer of the kneader.
That is, in the present invention, the largest particles are particles represented by the following formula (4).
It is preferable to select such that The following formula (12) is more preferable, and the following formula (13) is more preferable.
Is selected so that

[0027] D ≦ 100 (4) D ≦ 90 (12) D ≦ 60 (13)

If the maximum particle size exceeds 100 μm, even a thick sheet having a thickness of about 1 to 3 mm is likely to have protrusions on its surface, which may impair the appearance. Also, 1
Naturally, it cannot be blended in a thin sheet of 00 μm or less. Therefore, with the above-mentioned structure, good surface smoothness and appearance of the sheet can be obtained.

In order to exert further dispersibility,
It is preferable to select so as to satisfy the following formula (5).
More preferably, the following formula (14) is selected, and even more preferably, the following formula (15) is satisfied.

1 ≦ E ≦ 3 (5) 1 ≦ E ≦ 2.5 (14) 1 ≦ E ≦ 2 (15) E = d75 / d25 d75: Microtrack FRA laser type Sieve passage side cumulative 75% diameter (μm) of particles measured by particle size distribution meter d25: Sieve passage side cumulative 25% diameter (μm) of particles measured by Microtrac FRA laser type particle size distribution meter

That is, the closer E is to 1, the more uniform the particle diameter becomes, and good dispersibility can be obtained. In addition, it is possible to prevent the strength from decreasing due to the blending of high parts.

Further, in order to be able to mix a particularly high number of parts and to exhibit good dispersibility, the calcium carbonate of the present invention preferably has a primary particle diameter of 5 to 15 μm as observed by an electron microscope. Since it is difficult to judge with, the constant pressure ventilation type specific surface area Sw was used as an index. Heng pressure gas type specific surface area Sw is preferably from 15000 cm ² / g, more preferably 6500 cm ² / g or less, more preferably to adjust the primary particle size to be less than 5000 cm ² / g. Constant pressure ventilation type specific surface area Sw of 15000c
If it is larger than m ² / g, the dispersibility may be poor when it is mixed in a high proportion.

The calcium carbonate filler according to the present invention can be blended with a polyolefin resin to finally obtain a sheet in which calcium carbonate is uniformly dispersed.

More specifically, taking a polyethylene sheet as an example, the calcium carbonate powder of the present invention is mixed in an amount of 10 to 150 parts by weight with respect to 100 parts by weight of the resin to prepare a resin composition for a sheet. If necessary, in order to improve the sheet properties, a coupling agent, a lubricant such as a fatty acid, a fatty acid amide, an ethylene bisstearic acid amide, a sorbitan fatty acid ester, a plasticizer and a stabilizer, an antioxidant and the like may be added. Of course. In addition, the calcium carbonate of the present invention may be surface-treated with the above-mentioned organic material within the range of the particle size composition of the present invention, and then added to the resin. Furthermore, additives generally used in resin compositions for films, such as lubricants, antioxidants, heat stabilizers, light stabilizers, ultraviolet absorbers, neutralizing agents, antifogging agents, antiblocking agents, antistatic agents, A slip agent, a colorant, etc. may be blended, these additives may be mixed in advance with the calcium carbonate of the present invention, or surface-treated with these additives and then blended with the resin. Of course, it is necessary that calcium carbonate does not deviate from the range of the particle size constitution of the present invention by such mixing and surface treatment.

The resin composition for a sheet as described above is mixed using a known mixer such as a Henschel mixer, a tumbler type mixer and a ribbon blender. The calcium carbonate of the present invention is easy to mix and, in addition, for example, when mixed with a Henschel mixer, the mixing is easy, so that the mixing can be performed quickly. As a result, deterioration of the resin or agglomerates caused by seizure inside the mixer is reduced, and workability of mixing and strainer clogging in the kneading extruder in the subsequent step are less likely to occur.

After the resin composition is mixed with a mixer, the mixture is heated and kneaded with a single-screw or twin-screw extruder, a kneader, a Banbury mixer, etc., and a known molding machine such as T-die extrusion or inflation molding is used. Using, melting,
Make a sheet. Then, if necessary, it is uniaxially or biaxially stretched to obtain a sheet-shaped product.

Furthermore, if necessary, a plurality of steps up to the T-die extrusion in the above steps are combined to form a multilayer structure of the sheet during extrusion, or a step of laminating and stretching again during stretching is introduced. You can make it into a structure sheet,
There is no problem even if the sheet is cured at a temperature higher than normal temperature and lower than the melting temperature of the resin. Even if a recycled resin is used for the inner layer of a sheet having three or more layers, if the sheet made of the resin composition of the present invention is used for the surface layer, a sheet in which calcium carbonate fine particles are uniformly dispersed and has few defects can be obtained. Since the sheet covers the surface layer, it is possible to obtain a sheet having a multilayer structure which is excellent in strength characteristics and visually.

Further, in order to impart printability to the above-mentioned sheet, it is possible to subject the surface to a surface treatment such as plasma discharge or to coat the surface with an ink receiving layer. It is also possible to make a porous sheet by selecting When the porous sheet is used, since the calcium carbonate fine particles are well dispersed, the pores in the sheet can be made uniform.

[0039]

EXAMPLES The present invention will be described in more detail below with reference to examples, but it goes without saying that the present invention is not limited to these examples. In addition, the measurement of each characteristic value in the following description followed the following method.

The average particle size is obtained by dispersing a calcium carbonate suspension for 60 seconds using an ultrasonic disperser (Nippon Seiki Seisakusho: US-300T) to prepare a methanol dispersion. Using a laser particle size distribution analyzer (manufactured by Nikkiso Co., Ltd .: Microtrac FRA), the particle diameter (μm) of 50% by weight accumulated from the small particles in the particle size distribution measured for the methanol dispersion was taken as the average particle diameter.

The specific surface area of the powder was measured by using a constant pressure ventilation type powder specific surface area measuring device manufactured by Shimadzu Corporation.

Examples 1 to 6 As shown in Table 1, white sugar-crystalline limestone was crushed and classified,
Average particle size A, sharpness coefficient B (= d90 / d1
0), cumulative% C of A / 2 (μm) or less, maximum particle diameter D,
An additive made of calcium carbonate powder having a sharpness coefficient E (= d75 / d25) and a constant pressure ventilation type powder specific surface area Sw was prepared.

[0043]

[Table 1]

Comparative Examples 1 to 4 As shown in Table 2, white sugar crystalline limestone was crushed and classified,
Average particle size A, sharpness coefficient B (= d90 / d1
0), cumulative% C of A / 2 (μm) or less, maximum particle diameter D,
An additive made of calcium carbonate powder having a sharpness coefficient E (= d75 / d25) and a constant pressure ventilation type powder specific surface area Sw was prepared.

[0045]

[Table 2]

Examples 7 to 12 and Comparative Examples 5 to 8 Polypropylene resin and lubricant zinc stearate were added to the following using the additives consisting of the calcium carbonate powder prepared in Examples 1 to 6 and Comparative Examples 1 to 4. The resin composition was mixed with the composition, 50 kg of the resin composition was extruded at 200 ° C. at a feed rate of 50 kg / hour, the extruded strand was formed into a 1 mm thick sheet by a hand press, and a rectangular sheet of 5 cm × 10 cm was cut out. Strainer of kneading extruder (opening 250μ
The condition of clogging of m, opening of 400 μm)
Tables 3 and 4 show the results of evaluation of the presence or absence of the modified resin at the exit of the extruder die and the number of aggregates (bugs) of the PE sheet.

[0047] Combination Polypropylene resin (Mitsubishi Polypro MA-3) 100 parts by weight Zinc stearate 1 part by weight Sample (additives of Examples 1 to 6 and Comparative Examples 1 to 4) 100 parts by weight

Criteria for evaluation of clogging: 5 or less of clogging: ⊚, 6 to 20: ○, 21 to 100: Δ, strainer clogging less than half of the total area: ×, of strainer surface Half or more is clogged: XX.

Criteria for Coarse Particles in Sheet: No agglomerates (spots) are observed on both front and back surfaces of the sheet: ○, 1 or 2 agglomerates are observed on any surface: Δ, on any surface Three or more agglomerates are recognized: marked with x.

[0050]

[Table 3]

[0051]

[Table 4]

[0052]

As described above, when the additive comprising the calcium carbonate powder of the present invention is blended with the olefin resin, the workability during sheet production is excellent and the dispersibility is excellent. The produced sheet can be provided with an anti-blocking effect, excellent moisture permeability, and excellent water absorption.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hidemitsu Kasahara             Maruo Ka 1455 Nishioka, Uozumi Town, Akashi City, Hyogo Prefecture             Lucium Co., Ltd. (72) Inventor Katsuhiko Matsuo             Maruo Ka 1455 Nishioka, Uozumi Town, Akashi City, Hyogo Prefecture             Lucium Co., Ltd. (72) Inventor Shoji Ehara             Maruo Ka 1455 Nishioka, Uozumi Town, Akashi City, Hyogo Prefecture             Lucium Co., Ltd. F term (reference) 4F071 AA14 AA15 AA15X AA16                       AA17 AA18 AA20 AA20X                       AA21 AA21X AA22 AA22X                       AB21 AD02 AD06 AE17 BA01                       BB06 BC01                 4J002 BB001 BB021 BB031 BB041                       BB051 BB101 BB111 BB151                       BB171 BC041 DE236 FD016                       GF00 GG00 GQ00

Claims (6)

[Claims] 1. An additive for an olefinic resin sheet, comprising calcium carbonate powder satisfying the particle size distribution constitutions of the following formulas (1), (2) and (3). 2 ≦ A ≦ 30 (1) 1 ≦ B ≦ 25 where B = d90 / d10 (2) 0 ≦ C ≦ 25 (3) where A: average of calcium carbonate powder 50% of particle diameter (μm) measured by Microtrac FRA laser particle size distribution meter (d50) B: Sharpness coefficient of calcium carbonate powder d90: Particle measured by Microtrac FRA laser particle size distribution meter Sieve passing side cumulative 90% diameter (μm) d10: Sieve passing side cumulative 10% diameter (μm) of particles measured by Microtrac FRA laser particle size distribution meter C: A measured by Microtrac FRA laser type particle size distribution meter / 2 particle size sieve pass side cumulative percentage (%). 2. The additive for an olefin-based resin sheet according to claim 1, which comprises calcium carbonate further satisfying the following formula (4). D ≦ 100 (4) D: Maximum particle diameter (μm) measured by Microtrac FRA laser type particle size distribution meter. 3. The additive for an olefinic resin sheet according to claim 1, which comprises calcium carbonate which further satisfies the following formula (5). 1 ≦ E ≦ 3 However, E = d75 / d25 (5) d75: Microtrack FRA laser type cumulative 75% diameter (μm) of particles passing through sieve measured by particle size distribution meter d25: Microtrack FRA laser type Cumulative 25% diameter (μm) of particles passing through a sieve measured by a particle size distribution meter. 4. The constant pressure aeration type powder specific surface area Sw is 1500.
The additive for olefin-based resin sheets according to any one of claims 1 to 3, comprising calcium carbonate having a content of 0 cm ² / g or less. 5. A resin composition for an olefin-based sheet, which comprises the additive for an olefin-based resin sheet according to any one of claims 1 to 4. 6. The additive amount of the olefin resin sheet additive is 10 to 150 relative to 100 parts by weight of the olefin resin.
The resin composition for an olefin-based sheet according to claim 5, which is part by weight.