JPH09225810A - Naturally degradable polishing resin particles - Google Patents

Abstract

(57) [Abstract] [Problem] The substance is naturally degradable and less likely to pollute the environment. It has excellent durability and strength when it is mixed and stirred with an object to be polished, such as steel balls, and polished, and also spark discharge and It is an object of the present invention to provide new resin particles for polishing in which electrostatic troubles due to adhesion to other objects are suppressed. The present invention relates to a fiber-forming polymer (A) containing an aliphatic polyester as a main component and a “surfactant, polyalkylene ether, polyalkylene ether derivative”.
Of at least one antistatic agent (B) selected from the group, the volume resistivity of which is 1 × 10 ¹³ Ω · cm or less, and the melting point of the main crystal is 50 ° C. or more. Of the polymer composition having a melting endotherm of 5 Joule / g or more and an Izod impact strength of 3 kg · cm / cm or more.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel resin particle for polishing metal which is naturally degradable.

[0002]

2. Description of the Related Art Particles (pellets) made of a synthetic resin such as nylon are used for polishing and / or cleaning metals, particularly metal balls such as ball bearings and pachinko balls. For example, pachinko balls that are used and have dirt or rust,
When mixed and rubbed with nylon resin particles, dirt and rust are removed. As resin particles (hereinafter referred to as polishing particles) used for polishing and / or cleaning such metals, synthetic resins such as nylon have been conventionally used. However, conventional synthetic resins have a slow decomposition rate in a natural environment and generate a large amount of heat when incinerated, and therefore, it is necessary to review them from the viewpoint of protecting the natural environment. For this reason, naturally decomposable fibers made of aliphatic polyesters are being developed and are expected to contribute to environmental protection.

However, since the aliphatic polyester hardly absorbs water and has a high electric resistance, it tends to be easily charged by friction or the like, which causes problems such as spark discharge and adhesion of dust due to charging, and the abrasive particles are Not suitable. Among the aliphatic polyesters, polylactic acid and polyhydroxybutyrate (PHB), which have excellent heat resistance and strength and are expected to be put into practical use most
And the like have the drawbacks of being hard and brittle due to their high crystallinity and being inferior in durability and abrasiveness, and are not suitable for the above-mentioned abrasive particles.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel polishing particle which is made of a spontaneously decomposable resin and is excellent in polishing property and durability.

[0005]

The above object of the present invention is achieved by resin particles for metal polishing comprising a polymer composition which satisfies all the following items (1), (2) and (3). . (1) Polymer (A) containing aliphatic polyester as a main component
And "A surfactant having a lipophilic group and a hydrophilic group, having 2 carbon atoms.
A polyalkylene ether having an alkyl group of 4 to 4 and at least one compound (B) selected from the group of "derivatives of said polyalkylene ether",
Moreover, the volume resistivity is 1 × 10 ¹³ Ω · cm or less. (2) The melting point of the main crystal is 50 ° C. or higher, and the melting endotherm of the crystal is 5 Joules / gram or higher. (3) The Izod impact strength is 3 kg · cm / cm or more.

Here, the polymer having an aliphatic polyester as a main component means (1) a hydroxyalkylcarboxylic acid such as glycolic acid, lactic acid or hydroxybutylcarboxylic acid, (2) glycolide, lactide, butyrolactone or caprolactone. Aliphatic lactones such as (3) aliphatic diols such as ethylene glycol, propylene glycol, butanediol, hexanediol, etc.
(4) Polyethylene ether oligomers such as diethylene glycol, triethylene glycol, ethylene / propylene glycol, dihydroxyethyl butanol, polyethylene glycol, polypropylene recall, polyalkylene glycols such as polybutylene ether, (5) polypropylene carbonate, polybutylene Polyalkylene carbonate glycols such as carbonates, polyhexane carbonates, polyoctane carbonates and polydecane carbonates and oligomers thereof, (6) Aliphatic dicarboxylic acids such as succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid and decanedicarboxylic acid A component derived from an aliphatic polyester polymerization raw material such as an acid is used as a main component, that is, 50% by weight or more (particularly 60% or more). A shall, homopolymer of aliphatic polyester, aliphatic polyester copolymer, and aliphatic polyester other components, such as aromatic polyesters, polyethers, polycarbonates,
Polyamide, polyurea, polyurethane, polyorganosiloxane and the like are all copolymerized by 50% or less by weight (block copolymerization and / or random copolymerization) and / or a mixture thereof.

The purpose of modifying the aliphatic polyester by copolymerization or mixing is to lower the crystallinity, lower the melting point (lower the polymerization temperature and molding temperature), improve flexibility, impact resistance and elastic recovery, and heat resistance. And lowering or raising the glass transition temperature, improving abrasiveness, hydrophilicity, antifouling property and water repellency, and improving or suppressing degradability in a natural environment.

The abrasive particles of the present invention include a polymer (A) containing an aliphatic polyester as a main component, "a surfactant having a lipophilic group and a hydrophilic group, and a polyalkylene having an alkyl group having 2 to 4 carbon atoms. The composition comprises an antistatic composition in which at least one compound (B) selected from the group of "ether and derivative of the polyalkylene ether", that is, an antistatic agent is mixed. As described above, the polymer (A) containing an aliphatic polyester as a main component may be a homopolymer, a copolymer or a mixture.

The aliphatic homopolyester has a melting point of 130.
It is roughly classified into a high melting point type having a melting point of not less than ℃ and a low melting point type having a melting point of less than 130 ℃. Examples of the high melting point (hard) type are poly L-lactic acid (melting point: about 175 ° C.), poly D-lactic acid (about 17: the same).
5 ° C.), polyglycolic acid (about 230 ° C. in the same), polyhydroxybutyrate (about 180 ° C. in the same), and the like, all of which are hard and brittle. Examples of the low melting point (soft) type are polycaprolactone (about 60 ° C for the same), polyethylene adipate (about 44 ° C for the same), and polyethylene suberate (about 64 ° C for the same).
℃), polyethylene sebacate (about the same 72 ℃), polyethylene decamethylate (about the same 85 ℃), polybutylene succinate- (about the same 116 ℃), polybutylene adipate (the same about 69 ℃), polybutylene sebacate (Approximately 65
C.) and polyhexamethylene sebacate (about 75.degree. C.), and the like, all of which are soft and have excellent impact resistance. As described above, the high melting point homopolymer has high crystallinity, is hard and brittle, and is often inferior in impact resistance. Therefore, the second component and the third component are copolymerized and / or mixed to reduce the crystallinity. A polymer (A) that is plasticized (softened) and has a reduced glass transition point to room temperature or lower to improve impact resistance is preferably used as the polymer (A). As the plasticizer, for example, dicarboxylic acid esters such as dimethyl terephthalate, dimethyl phthalate, dioctyl phthalate, dibutyl adipate, dioctyl adipate and other well-known plasticizers are also preferably used. As a matter of course, the block or random copolymer or / and mixture of the above-mentioned soft type and hard type components having a melting point, a melting endothermic amount of crystals and an impact strength in the above-mentioned ranges are preferably used as the polymer (A).

The melting point of a polymer is measured by a scanning differential calorimeter (DS).
C) using a sample of about 10 mg, heating rate of 10 ° C / min
The temperature of the extreme value (center value) of the endothermic peak due to the melting of the crystal measured under the conditions of. If there are multiple melting peaks in a crystal, the highest temperature is used. The melting endotherm of the polymer is
In DSC measurement, it is an integrated value of all endothermic amounts of all endothermic peaks due to melting.

From the viewpoint of heat resistance and strength, the melting point is 50 ° C.
It is necessary that the temperature is 100 ° C. or higher,
Most preferably, the temperature is 130 ° C or higher. Similarly, from the viewpoint of heat resistance and strength, the melting endotherm of the crystal needs to be 5 joules (J) / gram (g) or more, preferably 10 J / g or more, and most preferably 20 J / g or more.

On the other hand, from the viewpoint of the durability of the abrasive particles, the impact strength must be 3 kg · cm / cm or more, and 4 kg.
・ Particularly preferably cm / cm or higher, 5 kg ・ cm / cm
The above is most preferred. Here, the impact strength (impact value) was measured according to the ASTM D-256 Izod impact test method by making a notched test piece having a width of 6.35 mm with a molding machine, and measuring the impact energy value per 1 cm width. It is what I asked for.

The abrasive particles of the present invention comprise a mixture of the polymer (A) and the compound (B), that is, an antistatic agent (antistatic agent). The antistatic agent (B) is one or more selected from a surfactant having a lipophilic group and a hydrophilic group, a polyalkylene ether having an alkyl group having 2 to 4 carbon atoms and a derivative thereof. As the lipophilic group, those having an alkyl group, an alkylallyl group or an aromatic nucleus are widely used, and the hydrophilic group is an ether bond, a hydroxyl group, an amino group, an amide bond, a carboxyl group (metal salt), a sulfone group (metal salt), Sulfate groups (metal salts), phosphoric acid groups (metal salts), etc. are widely used.

When the mutual affinity of the antistatic agent (B) and the polymer (A) is high, the mixed state becomes fine, uniform and stable, and the antistatic property and the mechanical properties of the mixture are enhanced. So desirable. In order to increase the affinity between the two, a polyester in which a polyalkylene ether, which is an active ingredient of an antistatic agent, or a polar group is introduced by copolymerization is particularly preferably used as the polymer (A). Similarly, an antistatic agent in which an aliphatic polyester component, in particular, a segment thereof is copolymerized is preferably used. That is, it is preferable that the antistatic agent (B) and the polymer (A) have a common segment or group. Here, the segment refers to a part of a molecular chain, and includes from oligomer grade having a polymerization degree of about 2 to 20 to polymer grade having a polymerization degree of 20 or more.

For example, polylactic acid and block copolymerized with polyethylene glycol of about 1 to 30%, particularly 3 to 15% are used as a polymer (A) and combined with an antistatic agent (B) containing polyethylene glycol as an active ingredient. Since both have a common segment called polyethylene glycol, they have high mutual affinity and are preferable. Similarly, polylactic acid is added to polyethylene glycol in an amount of about 1 to 20%, particularly 3 to 15%.
Since the block-copolymerized antistatic agent (B) and the polymer (A) containing polylactic acid as a main component have polylactic acid as a common segment, they have a high affinity and are a preferable combination. The weight ratio of the segments that both have in common is 1%
Or more is preferable, 3% or more is especially preferable, 5 to 20%
The degree is most widely used. Similarly, it is relatively easy to have an ester bond, an ether bond, an alkyl group, a polyalkylene alkylate segment, or the like as a common group.

One active ingredient of the antistatic agent (B) is a polyalkylene ether having 2 to 4 carbon atoms, that is, polyethylene glycol, polypropylene glycol, polybutylene ether, and a copolymer containing them (including an oligomer). ). Among them, polyethylene glycol is often used because it has the highest conductivity, and polyethylene glycol / polypropylene glycol copolymer is often used next. Polybutylene ether itself has low electric conductivity, but in combination with other components,
Good antistatic property can be obtained. In addition, modified products and derivatives of the above polyethers such as hydrophilic groups and polar groups such as hydroxyl group, carboxyl group, amino group, quaternary ammonium salt, amide group, urea group, urethane group, sulfone group,
A compound having a sulfate group, a phosphate group, or the like, which has a high electric conductivity, or which is chemically bonded by a copolymerization or other method to enhance conductivity is also used as the antistatic agent of the present invention. Particularly preferred. Similarly, in order to improve the affinity with the aliphatic polyester, various lipophilic components, for example, a derivative in which an alkyl group, an alkylallyl group, an alkyl ester group, a polyester segment, etc. are bound to a polyether are also preferable as the antistatic agent. .

The antistatic agent (B) is roughly classified into a low molecular type and a high molecular type. The low molecular weight type is a surfactant having a molecular weight of about 2000 or less, and is classified into nonionic type, anionic type, cationic type, amphoteric type and the like depending on the hydrophilic group, but generally has excellent conductivity and both are suitable for the purpose of the present invention. It is applicable.
The lipophilic group of the surfactant is not particularly limited, but those having high affinity with the aliphatic polyester, for example, saturated or unsaturated alkyl group having a linear or side chain, an alkylallyl group, an ester bond, etc. preferable. The hydrophilic group of the surfactant is not particularly limited, but those having one or more of the above polar groups such as a carboxyl group, an amino group, a sulfone group, a sulfuric acid group and a phosphoric acid group in addition to an ether bond and a hydroxyl group are preferable. Used.

The high molecular type has a molecular weight of about 2,000 or more, particularly 5,000 or more, and in many cases, those having a molecular weight of about 10,000 to 300,000, especially those having a molecular weight of 20,000 to 200,000 are widely used. As the high molecular type, polyethers, those in which polyethers and other components are bonded, and copolymers of polyethers with other polymers are preferably used. In the case of copolymerization, it is particularly preferable to pay attention to the affinity with the polymer (A) and to introduce, for example, a common segment as described above.

The mixture of the polymer (A) and the antistatic agent (B) has high electric conductivity in order to exhibit sufficient antistatic property, that is, the volume resistivity at 20 ° C. and 40% RH. (Specific resistance) is required to be 1 × 10 ¹³ Ω · cm or less, preferably 1 × 10 ¹² Ω · cm or less, and 1 ×
Most preferably 10 ¹¹ Ω · cm or less, 1 × 10 ⁸ to 1 ×
The range of 10 ¹² Ω · cm is most widely used. Polyethylene glycol homopolymer (unmodified) at 20 ℃, 4
The specific resistance at 0% RH is 6 × 10 ⁸ Ω · cm, and it is easy to mix this with an aliphatic polyester to produce an antistatic polymer (1) having a specific resistance in the above range. . (Normal aliphatic polyester that does not contain antistatic components is
It is an insulator with a specific resistance of 1 × 10 ¹⁴ Ω · cm or more). Further, a compound (surfactant) having a polar group such as sodium alkylbenzene sulfonate (surfactant) is mixed with an antistatic agent containing polyalkylene ether as an active ingredient in an amount of 1 to 50%, and in most cases 3 to 40%, The conductivity can be increased to about 2 to 100 times or more, and the antistatic property can be greatly improved.

The mixing ratio, mixing method and mixing structure of the polymer (A) and the antistatic agent (B) are not particularly limited. For the mixing, a mechanical stirrer such as a kneader, a vessel with a stirrer, a screw extruder, or a twin-screw kneading extruder may be used, and a static mixer that repeats fluid splitting and merging in multiple stages by a flow guiding device is used. Or both may be used together. As a specific example of the static mixer, the inventors of the present invention have disclosed Japanese Patent Publication No.
5526, the same 47-15527, the same 47-15532,
47-15528, 47-15533, 47-1
5533 and the like, and JP-A-47-3416.
6 and the like.

The mixed structure or dispersion form may be such that one component (for example, the polymer (A)) and the other component (for example, the antistatic agent (B)) are dispersed in the form of particles. May be dispersed in a layered, thin film or other continuous structure,
A plurality of types of structures may be mixed. Generally, when a low molecular type antistatic agent is used, a mixed structure in the form of particles is often obtained. When a high-polymer antistatic agent is used, a mechanical agitation method gives a fine particle-like mixed structure, which is mixed using a static mixing device and molded (particles) without mechanical agitation. By doing so, it is possible to obtain polishing particles having a continuous mixed structure in which an antistatic agent is dispersed in a matrix (matrix) polymer in the form of a thin layer or fine fibers. Particle-shaped mixed structure, the particles are elongated by the molecular orientation at the time of molding, in the particles for polishing,
It is often a large number of elongated needle-like dispersed forms. Generally, when an antistatic agent forms a continuous structure, it has high electrical conductivity,
Compared to the non-continuous structure, the molded product has much better anti-static property and a small mixing ratio (for example, 1/10 of the granular or acicular dispersion structure).
Degree) is often sufficient.

The mixing ratio of the antistatic agent is not particularly limited, but in the case of a low molecular type, it is often preferable to be in the range of about 0.1 to 5%, particularly 0.2 to 2%. If the mixing ratio is too large, the bleed-out phenomenon of the antistatic agent will be serious and tend to cause troubles. It is assumed that, in many cases, a low molecular weight (surfactant) type antistatic agent diffuses in the polymer and exudes to the surface, forms a thin surface coating (continuity), and exerts its effect.

In the case of a polymer type and a continuous structure, the mixing ratio of the antistatic agent is often 0.2 to 5%, particularly 0.5 to 3%. On the other hand, in a non-continuous structure such as polymer type particles or needles, the mixing ratio of the antistatic agent is 3% or more, particularly 5 to 5.
Often about 30% is required. As described above, the higher the affinity (miscibility) between the antistatic agent and the polymer (A), the finer the particles.
A uniform and stable mixed structure is obtained, and the excellent antistatic property and mechanical properties are excellent, which is preferable.

The molecular weight of the polymer (A) is not particularly limited. However, in order to obtain excellent strength, impact resistance, abrasion resistance, etc., the molecular weight of the polymer (A) is preferably 50,000 or more, particularly preferably 70,000 to 300,000, particularly preferably 100,000 to 200,000. Most widely used.

The size and shape of the polishing resin particles of the present invention are as follows.
There is no particular limitation. For example, the shape can be a cylinder, an elliptic cylinder, a polygonal cylinder, a sphere, a rugby ball shape, a disk shape, a polygonal plate shape, or a shape similar thereto. As for the size, those having a diameter, a length, a thickness and the like of about 1 mm to 6 mm, particularly about 1.5 to 4 mm are preferably used.

The method for producing the abrasive resin particles of the present invention is not particularly limited, but for example, the molten polymer composition is extruded from a circular or non-circular nozzle, cooled and solidified with water or the like, and the diameter is, for example, about 2 to 5 mm. After forming into strands, it may be cut into cylindrical or other particles, and the thickness is 1 to 3 m.
After extruding into a plate or sheet of about m, it may be cut into square or other plate-like particles, or may be extruded into cooling water from a nozzle and cut at the same time to form particles with rounded corners or spherical particles. Good. After forming the particles, a low-molecular type (surfactant type) antistatic agent may be impregnated, but a low-molecular type and / or high-molecular type antistatic agent may be mixed before the particles are molded.

The abrasive particles of the present invention include various pigments, dyes,
Coloring agents, water repellents, water absorbing agents, flame retardants, stabilizers, antioxidants, ultraviolet absorbers, metal particles, inorganic compound particles, inorganic abrasive particles (for example, diamond, silicon carbide, silica, titanium oxide, alumina, talc) Etc.), a crystal nucleating agent, a lubricant, a plasticizer, an antibacterial agent, a perfume, and other additives can be mixed.

The polishing particles of the present invention can be polished and washed on the surface of a metal molded product by contacting and rubbing with an object to be polished such as a ball bearing and a pachinko ball. For example, the metal balls and the polishing resin particles may be mixed and stirred in a container, and after mixing, they may be passed through a groove or a tubular passage. If the charging is remarkable in these steps, problems may occur due to spark discharge or adhesion of polishing particles to the wall surface. After polishing, the polishing particles are separated from the metal by sieving, gravity, centrifugal force, magnetism, etc., washed, if necessary, re-added with additives and reused.
In these steps, it is necessary that the polishing particles are less likely to be crushed or damaged, and therefore it is desirable that the particles have high impact resistance, are crystalline, and have a certain high melting point.

[0029]

EXAMPLES In the following examples,% and parts are by weight unless otherwise specified. The molecular weight of the aliphatic polyester is
In GPC analysis of a 0.1% chloroform solution of a sample, it is a weight average value of dispersion of a high molecular component excluding a component having a molecular weight of 1,000 or less.

The volume resistivity (resistivity) σ is obtained by applying a conductive adhesive to both end surfaces of a test piece obtained by injection molding and having a width of about 2 cm, a thickness of about 3 mm and a length of about 5 cm, and applying it to an electrode. As a result, a direct current of 100 V is applied, and the measured value R of the electric resistance after 1 minute is calculated by the formula σ = SR / L. Here, S is the cross-sectional area (cm ² ) of the test piece, and L is the length (cm) of the test piece. The temperature and humidity in the measuring chamber were 20 ° C. and 40% RH, and the test piece was left there for 24 hours or more and then measured.

Example 1 92 parts of polyethylene glycol (PEG) having a molecular weight of 45,000 and hydroxyl groups at both ends, L-
8 parts of lactot, 100 ppm of tin octylate, and 0.1 part of antioxidant Irganox 1010 manufactured by Ciba-Geigy Co. are mixed and melt-polymerized by stirring in a twin-screw extruder at 190 ° C. for 12 minutes in a nitrogen atmosphere to prepare PEG. / Polylactic acid = about 92 /
The antistatic agent AS1 of the block copolymer of 8 was obtained. Antistatic agent A
S1 has a polylactic acid segment of about 8% and has a molecular weight of about 48,000.

The above PEG was mixed with 20% sodium dodecylbenzene sulfonate, dehydrated in a molten state at 200 ° C. under a sufficient vacuum (1 Torr or less), returned to normal pressure, and further mixed with 0.1% of the above Irganox, to obtain antistatic. After polymerization of the agent AS1, the antistatic agent AS2
I got Antistatic agent AS1 has a melting point of 44 ° C and a specific resistance of 3 × 10 ⁹
Ω · cm, antistatic agent AS2 has melting point 43 ° C, specific resistance 2 × 10
It was ⁸ Ω · cm.

A 4/1 (molar ratio) random copolymer of polybutylene succinate (PBS) and polybutylene adipate (PBA) having a melting point of 88 ° C., a molecular weight of 120,000, and a hydroxyl group at both ends of 30 parts, L- 70 parts of lactide, 100 ppm of tin octylate, and 0.1 part of Irganox 1010, an antioxidant from Ciba Geigy, are mixed and mixed in a nitrogen atmosphere at 1
Melt agitation polymerization in a twin-screw kneading extruder at 90 ° C. for 7 minutes, and subsequently, in the second twin-screw kneading extruder, the above antistatic agent AS1.
Was melt-mixed with 7%, extruded from a circular nozzle, cooled into strands in water, and cut to obtain a chip C1. After the chip C1 was dried, it was further treated in a nitrogen atmosphere at 140 ° C for 4 hours (solid-state polymerization) to obtain polylactic acid and [PBS / PBA
7% of antistatic agent AS1 in a block copolymer with [copolymer]
Mixed polymer chips C2 were obtained. The molecular weight of chip C2 was 121,000, the content of [PBS / PBA copolymer segment] was about 30%, and two melting points of 168 ° C and 82 ° C were observed, but 168 ° C is a typical value. Chip C2 has a melting endotherm (total of both peaks) of 46 J / g, and has a columnar shape with a diameter of 2.5 mm and a length of 3 mm. The chip C2 was injection molded to prepare an attached test piece, and the Izod impact test and the electric resistance were measured. As a result, the impact strength was 5.3.
It was kgf · cm / cm and the specific resistance was 9 × 10 ¹⁰ Ω · cm.

A chip C3 is obtained in substantially the same manner as the chip C2 except that AS2 is used as the antistatic agent. The melting point, melting endotherm, shape and size of chip C3 are chip C
2, the molecular weight is 120,000, the impact strength is 5.2 kgf · cm / cm, and the specific resistance is 1 × 10 ¹⁰ Ω · c.
m.

For comparison, a chip C4 was obtained in the same manner as the chip C2 except that [PBS / PBA copolymer] was not used and the polylactic acid homopolymer was mixed with 7% of the antistatic agent AS1. . Chip C4 has a melting point of 175 ° C, a melting endotherm of 55 J / g, and an impact strength of 2.3 kgf · cm /.
cm, and the specific resistance was 3 × 10 ¹¹ Ω · cm.

Similarly, for comparison, a chip obtained in the same manner as the chip C2, but without using the antistatic agent AS1
5 is assumed. The melting point of the chip C5 is the same as that of the chip C2, the melting endotherm is 56 J / g, and the impact strength is 5.2 kgf.
-Cm / cm, and the specific resistance was 6 * 10 < ¹⁴ > [Omega] -cm.

Pachinko balls were mixed in a volume ratio of 1/1 to the chips C2 to C5, respectively, and the diameter was 30 cm,
It was put in a ball mill having a rotation speed of 30 rpm, and after being rotated and stirred for 24 hours, chips were taken out and the crushed state was examined.
Each chip has an inner diameter of 2.5 cm, a thickness of 2 mm, and an inclination of 45.
The state of adhesion to the inner surface of the chip was observed when passing through a transparent vinyl chloride tube having a length of 3 m and a length of 3 m. Table 1 shows the results. As can be seen in Table 1, the chip C according to the invention
2, C3 is mixed / compared with the chips C4, C5 of the comparative example.
Features such as less crushing due to stirring and smooth passage through the vinyl tube are clear.

[0038]

[Table 1]

[0039]

EFFECTS OF THE INVENTION According to the present invention, since it is naturally decomposable and generates little heat during combustion, environmental pollution is reduced,
Moreover, when it is mixed and contacted with a metal ball having a large specific gravity, it is not crushed or damaged and has excellent durability when washed and polished, while it is less charged due to friction, and spark discharge and adhesion to other objects occur. It is expected that new polishing resin particles, which have the characteristic of few phenomena, can be provided and contribute to environmental protection. The abrasive particles of the present invention are decomposed in soil, compost, water, etc. after use, and the decomposed products are utilized by microorganisms and plants. That is, when mixed with compost or soil, it is expected to contribute to the growth of fertilizers and crops.

Needless to say, since the aliphatic polyester containing polylactic acid as a main component uses agricultural products as a main raw material, it is also apparent that it suppresses an increase in carbon dioxide gas in the atmosphere as compared with synthetic resins using petroleum as a raw material. Is.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08J 3/12 CFD C08J 3/12 CFDA C08L 67/00 LPF C08L 67/00 LPF ZAB ZAB 71/02 LQE 71/02 LQE B29K 67:00

Claims (2)

[Claims] 1. Polishing resin particles comprising a polymer composition satisfying all of the following items (1), (2) and (3). (1) Polymer (A) containing aliphatic polyester as a main component
And "A surfactant having a lipophilic group and a hydrophilic group, having 2 carbon atoms.
A polyalkylene ether having an alkyl group of 4 to 4 and at least one compound (B) selected from the group of "derivatives of said polyalkylene ether",
Moreover, the volume resistivity is 1 × 10 ¹³ Ω · cm or less. (2) The melting point of the main crystal is 50 ° C. or higher, and the melting endotherm of the crystal is 5 Joules / gram or higher. (3) The Izod impact strength is 3 kg · cm / cm or more. 2. The volume resistivity is 1 × 10 ¹² Ω · cm or less, the melting point of the main crystal is 100 ° C. or more, the melting endothermic amount of the crystal is 10 joule / gram or more, and the Izod impact strength is The resin particles for polishing according to claim 1, which have a weight of 5 kg · cm / cm or more.