JP2002173579A - Resin composition and molded product given by using the resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide surface-treated inorganic particles, and to provide a resin composition so improved so to prevent vacant spaces, such as air bubbles, from generating when the composition is used in forming or molding a product, especially so improved as to prevent the air bubbles, aggregated foreign particles, voids, fallen-off particles, etc., from generating when used in forming a film, by using the particles. SOLUTION: The surface-treated inorganic particles are obtained by coating surfaces of inorganic particles of a material selected from silica, zeolite, alumina, and iron oxide with a polyhydric alcohol.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to surface-treated inorganic particles,
The present invention relates to a resin composition containing surface-treated inorganic particles and a polyester resin.

[0002]

2. Description of the Related Art Conventionally, thermoplastic resins, especially polyester resins, have excellent mechanical properties, dimensional stability, and physical and chemical properties such as chemical resistance. It is widely used in the field. On the other hand, it is known that troubles such as deterioration in workability, productivity, or reduction in product value occur due to poor slipperiness when a molding process for obtaining such a molded product or the product itself is handled.

In order to solve such a problem, there has been proposed a method in which fine particles are blended in a polyester resin to impart appropriate unevenness to the surface of a molded article to improve the slipperiness. Inorganic particles such as titanium, calcium carbonate, alumina, talc, kaolinite and the like are employed. However, such inorganic particles are likely to be agglomerated due to the hydrophilicity of the particle surface and the irregular shape and particle size of the particles, causing poor dispersion and poor wettability to the resin and deterioration of the resin, resulting in a molded article. At present, good films cannot be obtained because voids such as air bubbles are generated in the product, and foaming, lumpy agglomeration, voids, particle dropout, and the like occur particularly in a film processed at high temperature and high speed.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to improve the dispersibility and wettability of inorganic particles in a resin by treating the inorganic particles with a polyhydric alcohol. An object of the present invention is to provide a resin composition in which the occurrence of voids, particularly foaming, lumpy aggregation, voids, and falling off of particles during film formation is improved.

[0005]

That is, the present invention provides an inorganic particle selected from silica, zeolite, alumina and iron oxide, which has a surface coated with a polyhydric alcohol having two or more hydroxyl groups in a molecule. Characterized surface-treated inorganic particles.

Further, the present invention provides the above-mentioned surface-treated inorganic particles, wherein the polyhydric alcohol is at least one polyhydric alcohol selected from trimethylolpropane or trimethylolethane.

Further, the present invention provides the above-mentioned surface-treated inorganic particles, wherein the coating amount of the polyhydric alcohol is 0.01 to 10% by weight based on the weight of the inorganic particles.

Further, the present invention provides the above-mentioned surface-treated inorganic particles, wherein the inorganic particles are spherical particles having an aspect ratio of 0.5 to 1.

Further, the present invention is an antiblocking agent comprising the above-mentioned surface-treated inorganic particles.

[0010] The present invention further provides a resin composition comprising the above antiblocking agent and a polyester resin.

Further, the present invention is the above resin composition, wherein the intrinsic viscosity of the polyester resin is 0.3 to 1.1.

Further, the present invention provides the above resin composition, wherein the polyester resin has an intrinsic viscosity retention of 70% or more.

Further, the present invention is the above resin composition, wherein ΔP of the resin composition, which is an index of dispersibility of the inorganic particles in the polyester resin, is 50 or less.

Further, the present invention is a molded product obtained from the above resin composition.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in detail. The inorganic particles used in the present invention, as specific examples, silica, zeolite,
Alumina or iron oxide is preferred. The shape of the inorganic particles is not particularly limited, but is preferably spherical. Here, the term “spherical” refers to a particle shape having an aspect ratio of 0.5 to 1. That is, the ratio of the minor axis to the major axis (minor axis / major axis) observed by an electron microscope is 0.5 to 1. Of course, in order to obtain a film having good slipperiness and the like, it is most preferable that the film has a true spherical shape (short diameter / long diameter = 1).

The average particle size of the inorganic particles used in the present invention is as follows:
0.03 to 30 μm is suitable, preferably 0.5 to 30 μm.
10 μm. When the average particle diameter is smaller than 0.03 μm, particle agglomeration and poor dispersion occur, and the particle diameter for exhibiting an antiblocking effect is too small, so that the running property and abrasion resistance of the film are insufficient and larger than 30 μm. If the surface roughness of the film is too large,
Transparency is reduced, and the appearance of the film is poor due to generation of fish eyes.

The polyhydric alcohol used in the present invention is not particularly limited. In particular, trimethylolpropane, trimethylolethane, ethylene glycol, propylene glycol, glycerin, pentaerythritol, 1,2,6-
Polyhydric alcohols such as hexanetriol, sorbitol, inositol and polyvinyl alcohol are preferred.

The polyhydric alcohol used in the present invention is preferably added in an amount of 0.01 to 10% by weight based on the weight of the inorganic particles. If the content is more than 10% by weight, odors and smoke are likely to be generated due to decomposition of the polyhydric alcohol itself during the production of the resin composition, and foams and lumps are produced in the produced molded product, which is not preferable. If the amount is less than 0.01% by weight, the amount of the polyhydric alcohol on the surface of the inorganic particles is not sufficient, and the dispersion of the inorganic particles in the resin becomes poor.

As a method of treating the inorganic particles with these polyhydric alcohols, generally, a wet treatment method or a dry treatment method can be used. As a wet treatment, a surface treatment is performed by adding inorganic particles and a polyhydric alcohol to a solvent and uniformly mixing the resulting mixture using a high shear mixer such as a Henschel mixer or a super mixer, and then removing the solvent. The dry treatment can be performed by adding a polyhydric alcohol when crushing inorganic particles with a fluidizer such as a micronizer or a jet mill, and the fluid is usually compressed air, heated compressed air, Steam or the like is used. At this time, when the polyol is solid at room temperature, a polyol solution dissolved in a solvent may be used in the above-described processing step.For example, trimethylolethane is dissolved in ethanol and used as a ethanol solution of trimethylolethane in the processing step. be able to.

In particular, by heating and drying the surface-treated inorganic particles after or during the surface treatment, the hydrophobic surface becomes stronger, so that the water content due to moisture adsorption or the like is greatly reduced. The thus obtained low-moisture content surface-treated inorganic particles have various advantages, such as increased dispersing power and dispersion time, because the deterioration of the resin during kneading and dispersion in the resin is suppressed.

The surface-treated inorganic particles of the present invention can be used as an additive to a resin, but are preferably used as an anti-blocking agent for a film, especially, an oriented polyester film.

The polyester resin used in the present invention is a conventionally known resin. Terephthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid, 4,4'-
An aromatic dicarboxylic acid such as diphenyldicarboxylic acid or an ester thereof is condensed with an aliphatic glycol such as ethylene glycol, propylene glycol, 1,4-butanediol, diethylene glycol, tetramethylene glycol, 1,4-cyclohexanedimethanol or the like. It is a polyester that can be obtained by polymerization. Typical examples include polyethylene terephthalate and polybutylene terephthalate.

These polyester resins may be a combination of a plurality of carboxylic acid components and a plurality of diol components. That is, the polyester resin is preferably a homopolymer comprising the aromatic dicarboxylic acid component and the aliphatic glycol component, but may be a copolymer obtained by copolymerizing the third component in a small proportion. As the third component, for example, when the main component is ethylene terephthalate, diols such as diethylene glycol, propylene glycol, neopentyl glycol, polyalkylene glycol, and 1,4-cyclohexanedimethanol; succinic acid, adipic acid, and sebacic acid And dicarboxylic acids such as phthalic acid, isophthalic acid and 2,6-naphthalenedicarboxylic acid; and polyfunctional polycarboxylic acids such as trimellitic acid and pyromellitic acid. When the main component is ethylene-2,6-naphthalate, the same third component as described above (provided that 2,6-naphthalenedicarboxylic acid is terephthalic acid).

The polyester resin composition of the present invention contains surface-treated inorganic particles in a high concentration, and is diluted with a diluting resin (thermoplastic resin) at the time of molding to form a pellet-like polyester resin composition (hereinafter referred to as “polyester resin composition”). A masterbatch) or a pelletized polyester resin composition (hereinafter referred to as a compound) in which the concentration of the surface-treated inorganic particles is relatively low and is directly used for molding without dilution with a diluting resin. It may be. When the masterbatch and the compound are compared, there is no great difference in the processing steps for obtaining them. However, the cost of the masterbatch is slightly higher than that of the compound due to the high concentration of the surface-treated inorganic particles. However, in the case of a masterbatch, since a molded product can be obtained by diluting the masterbatch with an inexpensive diluting resin, a molded product manufactured from a masterbatch is cheaper than a molded product manufactured from a compound, and is preferable. .

More specifically, regarding the mixing ratio of the surface-treated inorganic particles to the polyester resin, the polyester resin composition of the present invention is prepared by mixing the surface-treated inorganic particles with the polyester resin in an amount of 0.01 / 99.99 to 80/20. The surface-treated inorganic particles and the polyester resin may be heated and kneaded using various mixers, dispersers, and kneaders.
Further, the resin composition of the present invention is preferably a pellet-like or flake-like master batch.

The limiting viscosity of the polyester resin in the resin composition of the present invention is determined by the deterioration (hydrolysis) of the polyester resin.
FIG. Polyester resin containing inorganic particles and polyester resin, heat-kneading, using a suitable solvent, dissolving the polyester resin in the resin composition and separating the inorganic particles, polyester resins of different concentrations Using a plurality of solutions, the viscosity of each resin solution is determined, and the viscosity / concentration value is plotted against the concentration according to a standard method,
This is a value obtained by extrapolating to a density of 0. The intrinsic viscosity retention is the intrinsic viscosity of the polyester resin in the resin composition,
The ratio with respect to the intrinsic viscosity of the polyester resin (blank) used in the resin composition, and the larger the value, that is, the closer the intrinsic viscosity of the polyester resin in the resin composition to the intrinsic viscosity of the blank, the more the resin becomes. The polyester resin in the composition has not deteriorated.

It is important that the intrinsic viscosity of the polyester resin in the resin composition of the present invention is from 0.3 to 1.1. The limiting viscosity of the polyester resin itself used for the production of the resin composition is at most about 1.3, but it is deteriorated (hydrolyzed) to some extent by heating and kneading during the production of the master batch. The viscosity tends to decrease. Even if the intrinsic viscosity of the polyester resin itself is considerably large, it is moderately degraded (hydrolyzed), or even if the intrinsic viscosity of the polyester resin itself is relatively small, the intrinsic viscosity is not easily reduced. Should be within the above range. That is, when a resin composition in which the intrinsic viscosity of the polyester resin in the resin composition is less than 0.3 is used for a molded article such as a film, the strength of the molded article such as a film is reduced. On the other hand, when a resin composition in which the limiting viscosity of the polyester resin in the resin composition exceeds 1.1 is used for a molded product such as a film, the resin composition is easily dispersed and distributed in the polyester resin for dilution. As a result, it becomes difficult to uniformly and quickly disperse the inorganic particles in the polyester resin, and the high-temperature processability of a molded article such as a film is impaired. Therefore, it is important that the polyester resin in the resin composition be in the above range.

The ΔP of the resin composition of the present invention indicates the degree of dispersibility of the inorganic particles in the polyester resin in the resin composition. Specifically, 40/80 / outlet of the Labo Plastomill single screw extruder 20 mm (manufactured by Toyo Seiki Co., Ltd.)
The master batch was passed through the master batch at 50 rpm at an extrusion temperature of 300 ° C., and the initial pressure (P
1) is determined, and an end pressure (P2) when the master batch is passed through a predetermined amount (an amount containing 100 g of inorganic particles in the master batch) is determined. Inorganic particles having poor dispersibility are present in the polyester resin in an agglomerated state, and depending on the degree of agglomeration, do not pass through the mesh and cause clogging of the mesh, resulting in an increase in pressure. Therefore, the smaller the pressure difference ΔP = P2−P1, the better the dispersibility of the inorganic particles.

The ΔP of the resin composition of the present invention is preferably 50 or less. If ΔP, which is an index of dispersibility, is 50 or less, the rise in resin pressure during molding of a film or the like is low.
Good long run property in production work and good physical properties such as bumps and transparency of molded products such as films. However, if ΔP is 50 or more, adverse effects on production workability and poor physical properties such as poor appearance of molded products Happens.

The resin composition of the present invention can be used as any molded product, but is preferably used as a film, and is particularly suitable as a stretched polyester film. The stretched polyester film may be uniaxially stretched or biaxially stretched, but is more effective in a biaxially stretched film because problems such as dropout of an antiblocking agent occur more remarkably. .

Such a stretched polyester film is
The polyester resin composition (compound) obtained by the above method or the resin composition obtained by further diluting the polyester resin composition (master batch) with the polyester resin is formed into a sheet and stretched uniaxially or biaxially. It is manufactured by a method.

The content of the anti-blocking agent (surface-treated inorganic particles) in the polyester film is 0.0
1 to 3% by weight, preferably 0.05 to 2% by weight is suitable. 0.01% by weight of antiblocking agent
If the amount is less than the above, the anti-blocking effect cannot be obtained.

The thickness of the film is generally from 10 to 100.
μm. Further, the film may contain, if necessary, an antistatic agent composed of a surfactant and an antifogging agent such as an antioxidant and a lubricant. Further, the film may be subjected to a corona treatment or the like.

[0035]

EXAMPLES The present invention will be described specifically with reference to Examples.
The present invention is not limited to these examples.
Hereinafter, examples and comparative examples will be described.

[Surface Treatment Method for Inorganic Particles] Examples 1 to 9 and Comparative Examples 1 to 9 Trimethylolethane or trimethylolpropane was prepared while pulverizing inorganic particles by a jet mill (fluid: compressed air, 0.3 MPa). An alcohol solution was added to obtain surface-treated inorganic particles. Based on Table 1, the coating amount of the polyhydric alcohol on the inorganic particles was adjusted by changing the treatment weight of the inorganic particles and the supply concentration or the supply flow rate of the treating agent so as to be a predetermined coating amount.

[Preparation Method of Masterbatch] 50% by weight of homopolyethylene terephthalate ((η) = 0.630) and 50% by weight of surface-treated inorganic particles are melt-kneaded in a melt-kneading machine to obtain a pellet-shaped resin composition (master). Batch).

The intrinsic viscosity retention of the polyester resin in the obtained master batch was determined according to the following method. In addition to evaluating the dispersibility of the obtained master batch, a film was prepared using the obtained master batch according to the following method, and the physical properties and the like were evaluated. Table 1 shows the results
Shown in In Comparative Examples 6 and 8, an odor was generated during the production of the master batch.

[Intrinsic Viscosity (η)] and [Intrinsic Viscosity (η) Retention] The intrinsic viscosity (η) of the polyester resin was 0.1%.
g, 0.3 g, 0.5 g of the masterbatch,
Using 100 ml of a mixed solvent of phenol / tetrachloroethane = 50/50 (weight ratio), the polyester resin in the masterbatch was dissolved, and the surface-treated inorganic particles were removed by centrifugation.
The viscosity at 0 ° C. was measured and determined according to a standard method. In the case of a blank, the limiting viscosity was determined in the same manner as described above, except that the polyester resin itself was used instead of the master batch, and the surface-treated inorganic particles were not removed by centrifugation. The intrinsic viscosity retention is the intrinsic viscosity of the polyester resin in the master batch / the intrinsic viscosity of the blank.

[Evaluation method of dispersibility] 40/80/40/80 / outlet of Labo Plastomill single screw extruder 20 mm
The master batch was passed through the master batch at 50 rpm at an extrusion temperature of 300 ° C., and the initial pressure (P
1) is determined, and an end pressure (P2) when the master batch is passed through a predetermined amount (an amount containing 100 g of inorganic particles in the master batch) is determined. Inorganic particles having poor dispersibility are present in the polyester resin in an agglomerated state, and depending on the degree of agglomeration, do not pass through the mesh and cause clogging of the mesh, resulting in an increase in pressure. Therefore, the smaller the pressure difference ΔP = P2−P1, the better the dispersibility of the inorganic particles.

[Film forming method] 40 parts by weight of the obtained master batch, homopolyethylene terephthalate
((η) = 0.630) 60 weights were mixed and melt extruded at 270-300 ° C. to obtain a 200 μm sheet. 90
The film was simultaneously biaxially stretched at a temperature of 20 ° C. to form a 20 μm film.
The film formation state of the film and the smoothness of the obtained film were evaluated.

[Film Production State] A: No break at all. ：: almost no break. Δ: Occasional fracture. ×: frequently broken.

[Generation of film spots]: Visual evaluation. A: There are no bumps. ：: Almost no irregularities Δ: Slight bumps occur. ×: Significant bumps occur.

[0044]

[Table 1]

Silica 1: spherical (aspect ratio 0.80), average particle size 1.6 μm, synthetic silica by sedimentation method TME: trimethylolethane Silica 2: average particle size 2.7 μm, gel synthetic silica TMP: trimethylolpropane Zeolite 1: Spherical (aspect ratio 0.94), average particle size 5μ
m zeolite 2: average particle size 4.2 μm

[0046]

According to the present invention, the dispersibility and wettability of the inorganic particles in the resin are improved by treating the inorganic particles with a polyhydric alcohol. It has become possible to provide a resin composition in which the occurrence of lumps, agglomeration, voids, particle detachment and the like is improved.

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 4F071 AA45 AA46 AA88 AB18 AB26 AD02 AH04 AH05 AH19 BA01 BB06 BB07 BB08 BC01 4G056 AA04 AA23 BA00 4J002 CF061 CF071 CF081 DE116 DE146 DJ006 DJ016 FB086 GG01 GG02 G

Claims (10)

[Claims] 1. Surface-treated inorganic particles obtained by coating the surface of an inorganic particle selected from silica, zeolite, alumina and iron oxide with a polyhydric alcohol having two or more hydroxyl groups in a molecule. 2. The surface-treated inorganic particles according to claim 1, wherein the polyhydric alcohol is at least one polyhydric alcohol selected from trimethylolpropane and trimethylolethane. 3. The surface-treated inorganic particles according to claim 1, wherein the coating amount of the polyhydric alcohol is 0.01 to 10% by weight based on the weight of the inorganic particles. 4. An inorganic particle having an aspect ratio of 0.5 to 0.5.
4. The method according to claim 1, wherein the particles are spherical particles.
The surface-treated inorganic particles according to any one of the above. 5. An anti-blocking agent comprising the surface-treated inorganic particles according to claim 1. 6. A resin composition comprising the anti-blocking agent according to claim 5 and a polyester resin. 7. The polyester resin has an intrinsic viscosity of from 0.3 to 0.3.
The resin composition according to claim 6, which is 1.1. 8. A polyester resin having an intrinsic viscosity retention of 7
The resin composition according to claim 6, which is 0% or more. 9. The resin composition according to claim 6, wherein ΔP of the resin composition, which is an index of dispersibility of the inorganic particles in the polyester resin, is 50 or less. 10. A molded article obtained from the resin composition according to claim 6.