JP3351124B2 - Surface modifier for plastic molded products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface modifier for plastic molded articles. More specifically, the present invention relates to an agent which imparts fine irregularities to the surface of a plastic molded product without impairing the appearance and optical properties, and improves surface properties such as anti-blocking property, scratch resistance, and slip property.

[0002]

2. Description of the Related Art Conventionally, plastic moldings have been made to have fine irregularities on their surfaces, and surface modification such as anti-blocking property, scratch resistance, and slip property has been performed. As a method of making the surface of a plastic molded article fine and uneven, a method of mixing and molding inorganic fine particles such as silicon dioxide and titanium oxide and insoluble and insoluble polymer fine particles in plastic,
Alternatively, a method of applying these to the surface of a plastic molded product is widely used.

For example, Japanese Patent Publication No. 47-2180 discloses that the particle size is 0.1 to 2 μm and has at least one functional group among an amino group, a hydroxyl group, a carboxyl group, an epoxy group and a maleic anhydride unit. 0.1-30%, preferably 1-5% of insoluble and infusible crosslinked polymer fine powder
A method for producing a polymer film having improved slipperiness obtained by mixing and molding is disclosed. Also, Japanese Patent Application Laid-Open No. 57-6452
In JP-A No. 2 (KOKAI), a polymer fine powder having a crosslinked structure having a particle diameter of 3 to 40 μm and having no melting point is mixed with a polypropylene resin in an amount of 0.02 to 0.8% by weight, melt-extruded, and then cooled. In addition, there is disclosed a stretched polypropylene resin film obtained by stretching the film in at least a uniaxial direction and having good transparency, and excellent in slipperiness and blocking resistance. Further, JP-A-6-107868 discloses an average particle size of 0.4 to 7 μm per 100 parts by weight of a polyolefin resin.
0.005 to 2 parts by weight of a crosslinked particle of a polymer copolymerized with an acrylic monomer / styrene monomer as a main component, is excellent in transparency, and has slipperiness and scratch resistance. A good polyolefin resin film is shown.

Further, Japanese Patent Application Laid-Open No. 5-214120 discloses a biaxially oriented polypropylene film containing 0.01 to 0.3% by weight of crosslinked inert organic polymer particles, wherein the average particle size of the inert organic polymer fine particles is A biaxially oriented polypropylene film with an improved scratch resistance characterized by a diameter of 0.5 to 7 μm is shown. JP-A-6-8
No. 319 discloses a specific projection height, projection density, three-dimensional average surface roughness, center line average surface roughness using calcium carbonate, colloidal silica, crosslinked polystyrene particles, etc. having an average particle size of 0.1 to 1 μm. This shows a biaxially oriented polyester film for a magnetic recording medium having good scratch resistance having the following.

On the other hand, as a slipperiness improving material applied to a plastic surface, Japanese Patent Application Laid-Open No. Hei 1-222164 discloses an average polymer obtained by emulsion polymerization of a monomer mixture containing methyl methacrylate as a main component under specific conditions. Particle size is 0.01 ~
A fine particle polymer having a particle diameter distribution represented by a quotient of a weight average particle diameter (Dw) and a number average particle diameter (Dn) of not more than 1.2 within a range of 0.1 μm and a binder; A slip improver is shown in which coalescing is at a rate of 0.1 to 50% by weight of solids.

[0006]

However, the use of inorganic particles as a surface modifier has a bad effect on the mechanical properties, processability, transparency, etc. of plastics because the affinity between the plastic and the surface modifier is low. Or the surface modifier may fall off, or the plastic surface may be damaged. In particular, there is a disadvantage that many voids are generated by using inorganic particles as nuclei at the time of forming a stretched film or the like, and the film properties such as appearance and transparency are remarkably deteriorated.

On the other hand, when the crosslinked polymer fine particles are used as the surface modifier, the affinity between the crosslinked polymer fine particles and the plastic becomes better than that of the inorganic particles, so that the mechanical properties and the like of the plastic are remarkably deteriorated. No occurrence of voids at the time of molding processing occurs, and the optical properties are not easily deteriorated. However, the balance between the antiblocking property, the scratch resistance, the slip property, and the optical properties is not yet sufficiently satisfactory. That is, when a crosslinked polymer fine particle having a size of 1 μm or less as shown in JP-A 1-222164 is used,
Because the irregularities formed on the plastic surface are too small,
The anti-blocking property and the slip property are insufficient, and it must be added in a large amount of 1 to 5% with respect to the plastic, which has a considerable adverse effect on the optical properties and mechanical properties of the plastic.

On the other hand, those using crosslinked polymer fine particles having an average particle size of 1 μm or more do not necessarily show good antiblocking properties, slip properties and optical properties due to the particle size distribution. In other words, when coarse particles are contained, the coarse particles become lumpy and not only impair the appearance of the plastic molded article, but also voids are easily generated by using the coarse particles as nuclei at the time of molding such as stretching, and optical properties such as appearance are reduced. The characteristics are further deteriorated. In addition, the coarse particles damage the plastic surface when rubbed, resulting in poor scratch resistance.

Accordingly, it is an object of the present invention to provide a surface modifier for a plastic molded article which imparts excellent antiblocking properties, slip properties and scratch resistance even when used in a small amount without impairing the appearance and transparency of the plastic. .

[0010]

That is, according to the present invention, a particle having a volume mode particle diameter of 1 to 10 .mu.m and a particle occupying less than 10% of particles having a particle diameter larger than 1.3 times the particle diameter is 10% or less. An object of the present invention is to provide a surface modifier for plastic molded articles comprising polymer fine particles having a distribution and a particle diameter enlargement rate of 1 to 1.5 after immersion in chloroform at 25 ° C for 3 hours.

The polymer fine particles of the present invention have a volume mode particle size of 1 to 10 μm. Here, the volume mode particle size is a particle size that is a maximum value of a particle size distribution curve expressed by a volume fraction, and particles having a particle size near this volume mode particle size are most contained. Is shown. When the volume mode particle size is smaller than 1 μm, the unevenness of the surface of the plastic molded product is too small, and the anti-blocking property and the slip property are not sufficiently exhibited. On the other hand, if it is larger than 10 μm, the unevenness of the surface of the molded plastic product is too large, and light diffusion occurs on the plastic surface, which deteriorates the appearance.

Further, the polymer fine particles are composed of particles having a particle diameter larger than 1.3 times the volume mode particle diameter by volume.
% Or less. If it is more than 10%, coarse particles are contained in a large amount, so that scratch resistance and optical properties are deteriorated. Further, particles near the volume mode particle diameter, which are most frequently present, substantially contribute to antiblocking properties and slip properties. Gone
The balance between blocking properties, slip properties, scratch resistance and optical properties is poor.

The polymer fine particles are placed in chloroform at 25 ° C.
And the particle diameter enlargement rate after immersion for 3 hours at 1 to 1.5. When the particle diameter enlargement rate is larger than 1.5, the resin cannot be dispersed in the plastic by melt-kneading, or when the surface is coated with a solvent, or when it is subjected to molding such as stretching, the shape of the particles cannot be maintained. As a result, the irregularities on the surface of the molded product are reduced, and the surface modifying performance is not sufficiently exhibited.

The polymer fine particles of the present invention include, for example, addition polymers of vinyl monomers such as ethylene, propylene, butadiene, styrene, (meth) acrylates and acrylonitrile, as well as condensation products of alkylene terephthalate, nylon and polycarbonate. Polymer: epoxy resin,
Thermosetting resin such as phenolic resin: polymer fine particles composed of the same. When the polymer fine particles are composed of the above-mentioned addition polymer and condensation polymer, they are polymers having a crosslinked structure obtained by copolymerizing a polyfunctional monomer.

[0015] As a method for producing polymer microparticles of the present invention, to obtain a vinyl-monomer For example suspension polymerization, micro suspension polymerization, as a particulate in the polymerization processes known from the prior art, such as dispersion polymerization, Thereafter, the mode particle size of 1.3
There is a method of classifying particles such that particles larger than twice the particle size are 10% or less of the whole.

As a method for classifying the particles, there are known methods such as air classification for classifying dried powders and wet classification for classifying particles in a state of being dispersed in a liquid. In particular, for the polymer particles obtained by dispersion polymerization or microsuspension polymerization, it is more preferable to wet classify the slurry obtained after polymerization as it is, from the viewpoint of better workability and classification accuracy.

Examples of the plastic of the plastic molded article of the present invention include polyolefins such as polyethylene and polypropylene, polyamides such as nylon, polyesters such as polyethylene terephthalate, celluloses such as cellophane, polyvinyl chloride, polyvinyl alcohol, polyvinylidene chloride, and the like. Examples include polystyrene, polymethyl methacrylate, and ABS resin.

The molded plastic articles of the present invention include cast films, inflation films,
Films such as stretched films, sheets, and molded products of various shapes. These molded articles are formed by well-known molding methods, for example, extrusion molding, calender molding, hollow molding, vacuum molding and the like.

In order to apply the polymer fine particles of the present invention to a plastic molded article whose surface is to be modified, a suitable amount of a plastic material is mixed in advance as a raw material before the plastic material is molded into a desired molded article. There is. That is, the method is a method in which the polymer fine particles are mixed with the plastic material, melted and kneaded with an extruder, and then molded.
There is a method in which the plastic material and the polymer fine particles are mixed in a solvent in which the plastic material is dissolved, followed by solvent casting. The addition amount of the surface modifier varies depending on the particle size of the surface modifier and the plastic material to be modified, but is usually 0.1 to 1% by weight.

Further, as a method of applying only to the surface of a plastic molded article, a method of mixing the polymer fine particles with a paint or a solvent and applying the mixture to a plastic molded article, There is a method to do.

[0021]

According to the surface modifier for molded plastic products of the present invention, the surface irregularities of the molded plastic products become uniform,
Excellent anti-blocking properties, lubricity,
Shows scratch resistance, no change in appearance, and little loss of optical properties.

[0022]

EXAMPLES The present invention will be described specifically with reference to examples, but the present invention is not limited to these examples.
The evaluation and measurement methods in the examples are as follows. -Volume mode particle size and particle size distribution of polymer fine particles: The particle size distribution is measured with a light diffraction scattering particle size measuring device (Microtrac FRA) manufactured by Reeds & Northrup, and the volume mode particle sizes Dm and Dm are determined. The ratio F of particles (coarse particles) larger than 1.3 times was shown. -Particle diameter enlargement rate after immersion in chloroform at 25 ° C for 3 hours: The particle diameter of polymer fine particles after immersion in chloroform at 25 ° C for 3 hours was measured, and the ratio V to the original particle diameter was obtained. expressed.・ Surface roughness of plastic molded products: in accordance with JIS-B-0601
The center line average surface roughness Ra was measured using a stylus type surface roughness meter SE-3FA manufactured by Kosaka Laboratory. The measurement was performed using a detector PUDA5, a vertical magnification of 50,000 times, a cutoff of 0.25 mm, and a measurement length of 4 mm.
It was expressed as an average value of 20 measurements at a measurement speed of 0.5 mm / sec. -Static friction coefficient [mu] s and dynamic friction coefficient [mu] d of a plastic molded product: Measured in accordance with JIS-K7125-1987.・ Scratch resistance of plastic molded products: JIS-L0823-19
According to Toyo Seiki's dyeing fastness friction tester, 2
A friction test was performed 500 times under a load of 00 gf, and the increase in haze before and after the test was measured.・ Optical characteristics of plastic molded products: In accordance with JIS K 7105-1981, using Suga Test Instruments Co., Ltd.'s image clarity measuring device ICM-1DP, 45 ° reflection, optical comb width 0.125 mm, clear image. The degree was measured.

Wet classification of polymer fine particles: The classification point was adjusted by the number of rotations and the feed speed using a continuous high-speed centrifuge H-600 manufactured by Kokusan.

Reference Example 1 (Production of Polymer Fine Particles A) In a glass flask equipped with a stirrer, an aqueous phase in which 0.05 part by weight of sodium dodecylbenzene sulfate was dissolved in 100 parts by weight of ion-exchanged water, and 0.1 part by weight of lauroyl peroxide Parts, a monomer mixture obtained by dissolving 0.4 parts by weight of ethylene glycol dimethacrylate in 35 parts by weight of methyl methacrylate was charged, and a homomixer (Tokusai Kika Kogyo Co., Ltd.)
And a high-speed stirring at 6000 rpm for 30 minutes to disperse the monomer mixture into the aqueous phase. 65
° C, and the polymerization was continued for 2 hours.
The polymerization was completed in one hour. The obtained polymerization slurry was fed to a continuous high-speed centrifuge at a feed rate of 0.2 L / min and a rotation speed of 200.
Wet classification was performed at 0 rpm, and polymer fine particles A were obtained from the non-settling liquid. Table 1 shows the properties of the obtained polymer fine particles A.

Reference Example 2 (Production of polymer fine particles B) In Reference Example 1, the rotational speed of the homomixer was set to 4000 rpm.
m, and the polymer fine particle B was obtained in the same manner as in Reference Example 1 except that the rotation speed of the continuous high-speed centrifuge was 500 rpm. Table 1 shows the properties of the obtained polymer fine particles B.

Reference Example 3 (Production of polymer fine particles C) A glass flask equipped with a stirrer was charged with 60 parts by weight of ethanol and 40 parts by weight of ion-exchanged water, and 1 part by weight of 2-hydroxypropylcellulose was added and dissolved. A monomer mixture in which 10 parts by weight of methacrylate, 0.4 part by weight of ethylene glycol dimethacrylate, and 0.1 part by weight of 2,2′-azobisisobutyronitrile were previously added was added. The temperature was raised to 65 ° C., and polymerization was continued for 15 hours to obtain polymer fine particles C. Table 1 shows the properties of the obtained polymer fine particles C.

Reference Example 4 (Production of polymer fine particles D) Reference Example 2 was the same as Reference Example 2 except that the wet classification was not performed.
In the same manner as in the above, polymer fine particles D were obtained. Table 1 shows the properties of the obtained polymer fine particles D.

Reference Example 5 (Production of polymer fine particles E) Polymer fine particles E were prepared in the same manner as in Reference Example 1, except that 0.4 parts by weight of ethylene glycol dimethacrylate was changed to 0.1 parts by weight. I got Table 1 shows the properties of the obtained polymer fine particles E.

Reference Example 6 (Production of Polymer Fine Particles F ) 100 parts by weight of ethanol was charged into a glass flask equipped with a stirrer, 1 part by weight of 2-hydroxypropylcellulose was added and dissolved, and then 10 parts by weight of styrene and 55% of divinyl were added. A monomer mixture in which 0.8 parts by weight of benzene and 0.1 parts by weight of benzoyl peroxide were previously dissolved was added.
The temperature was raised to 78 ° C., polymerization was continued for 15 hours, and the polymerization was completed. The obtained polymer slurry was fed to a continuous high-speed centrifuge at a feed rate of 0.1.
Wet classification was performed at 2 L / min at a rotation speed of 2,000 rpm, and polymer fine particles F were obtained from the non-precipitated liquid . Obtained polymer fine particles F
The properties of are shown in Table 1.

Examples 1 to 4 and Comparative Examples 1 to 6 100 parts by weight of methacrylic resin (PMMA), the kind shown in Table 2 and a predetermined amount of polymer fine particles were mixed with a Henschel mixer, and a 20 mm After being melt-kneaded at 260 ° C. by an extruder and extruded from a T-die, it was cooled by a cooling roll at 60 ° C. to obtain a sheet having a thickness of 1 mm. Table 2 shows the evaluation results of the obtained sheets.

Examples 5 and 6 , Comparative Examples 7 and 8 100 parts by weight of polypropylene (PP), the kind shown in Table 2, and a predetermined amount of polymer fine particles were mixed with a Henschel mixer, and the mixture was extruded with a T-die into a 20 mm extruder. After melt-kneading at 260 ° C. with a machine and extruding from a T-die, the mixture was cooled with a cooling roll at 60 ° C. to obtain a 0.8 mm thick sheet. Table 2 shows the evaluation results of the obtained sheets.

[0032]Examples 7 and 8  100 parts by weight of polystyrene (Pst) and the seeds shown in Table 2
And a predetermined amount of polymer particles are mixed with a Henschel mixer
And melt kneading at 220 ° C with a 20mm extruder equipped with a T die
Then, after extruding from the T die, with a cooling roll of 80 ℃
After cooling, a sheet having a thickness of 1 mm was obtained. Evaluation of the obtained sheet
The results are shown in Table 2.

[0033]

[Table 1]

[0034]

[Table 2]

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-50-51142 (JP, A) JP-A-55-152719 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 1/00-101/16 C08J 3/12

Claims (1)

(57) [Claims] (1) a particle having a volume mode particle size of 1 to 10 μm, a particle size distribution in which particles having a particle size larger than 1.3 times the particle size account for 10% or less of the whole; A surface modifier for plastic molded articles comprising polymer fine particles having a particle diameter enlargement ratio of 1 to 1.5 after immersion at 3 ° C. for 3 hours.