JP2001277131A - Blasting material and blasting process - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a blasting material suited for the process of blasting the surface of a resin product. SOLUTION: The blasting material comprises base resins blended with an antistatic agent. One or more than two kinds of resins selected from among melamine resin, urea resin, phenol resin, ketone resin, epoxy resin and guanamine resin are suitable for use as the base resins. A surfactant may be of anionic, cationic, or noionic type.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blasting material for blasting the surface of a member, and more particularly to a blasting material for blasting the surface of a resin product. The present invention also relates to a blast processing method using the blast material.

[0002]

2. Description of the Related Art When a resin product such as a urethane bumper of an automobile is reused, the surface coating may be peeled off, and blasting may be performed for this peeling treatment.

[0003] As a blasting material for such blasting, glass beads, cone powder, walnut powder and the like are used.

[0004] This projectile is prevented from being charged,
An aqueous solution of a surfactant is sprayed on the projecting material in order to prevent the projecting material and the fine powder from adhering to the inner surface of the projecting device, but the effect is not long lasting.

[0005] Japanese Patent Application Laid-Open No. 9-225836 discloses a blast material in which the surface of synthetic resin particles is coated with a conductive polymer.

[0006]

As described above, a blast material sprayed with an aqueous solution of a surfactant to prevent static charge is:
This antistatic effect does not last long. Also, Japanese Patent Application Laid-Open No. 9-2
In the case where the particle surface is coated with a conductive polymer as disclosed in Japanese Patent No. 25,836, the cost is considerably high, and when the coating is worn, the antistatic effect is lost.

[0007] In the blast treatment of a resin product using glass beads, there is a problem that the surface of the resin product is severely worn; the crushing rate of the glass beads is high and it is difficult to reuse the glass beads.

In the blast treatment using corn powder or walnut powder, there is a problem that the treatment requires a long time; the adhesion of paint or the like is not well removed; and the work environment is poor and dust countermeasures are required.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, reliably prevents charging, maintains the antistatic effect for a long period of time, and deposits such as paint without damaging the surface of a resin product. It is an object of the present invention to provide a blasting material capable of efficiently removing and removing blasting, and a blasting method using the blasting material.

[0010]

The blasting material of the present invention (claim 1) is characterized by comprising an antistatic agent such as a surfactant.

In such a shot material and blasting method, since an antistatic agent such as a surfactant is contained in the base resin, an antistatic effect is obtained, and the shot material particles are broken or worn. Even if it does, the antistatic effect is continuously exhibited. Therefore, when the surface of a resin product is subjected to blasting treatment using the shot material of the present invention, it is possible to efficiently remove deposits such as paint without damaging or hardly damaging the surface of the resin product.

In the present invention, one or more of melamine resin, urea resin, phenol resin, ketone resin, epoxy resin and guanamine resin are suitable as the base resin.

The melamine resin, urea resin, phenol resin, ketone resin, epoxy resin and guanamine resin are all excellent in heat resistance and impact resistance, and do not deteriorate even when heated when projected, and are not affected by the impact of projection. Since it is hard to powder, it can be used repeatedly. In addition, since the powder is hardly powdered, the environment for the blasting process is also good.

In the blasting method of the present invention, blasting of the surface of an object to be blasted is performed using such a blasting material.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The shot material according to the present invention is characterized in that a shot material for blasting the surface of a resin product is blended with an antistatic agent such as a surfactant. As the base resin, one or more of melamine resin, urea resin, phenol resin, ketone resin, epoxy resin and guanamine resin are suitable.

Incidentally, the shot material made of melamine resin is particularly excellent in heat resistance and impact resistance. Projectiles made of urea resin are particularly excellent in impact resistance. Projectiles made of phenolic resin are particularly excellent in heat resistance. Projectiles made of ketone resins are particularly excellent in wear resistance. The projectile made of epoxy resin is particularly excellent in heat resistance and water resistance. Projectiles made of guanamine resin are particularly excellent in impact resistance.

When two or more resins are used, a blend of two or more resins may be used, or a copolymer of two or more resins may be used. It may be obtained by copolymerizing a monomer.

The surfactant to be added to the base resin may be any of anionic, cationic and nonionic surfactants.
The compounding amount in the case of the anionic surfactant is as follows.
0.001 to 10 parts by weight, especially 0.01 to 10 parts by weight per 0 parts by weight
5 parts by weight is preferable, and the amount of the cationic surfactant is 0.001 to 1 based on 100 parts by weight of the base resin.
0 parts by weight, particularly 0.01 to 5 parts by weight, is suitable. In the case of the nonionic surfactant, the compounding amount is 0.001 to 10 parts by weight, particularly 0.01 to 5 parts by weight, based on 100 parts by weight of the base resin. Parts are preferred. In any case, if the amount of the surfactant is below the above range, the antistatic effect is insufficient, and if the amount of the surfactant exceeds the above range, the strength of the particles made of the base resin may be reduced. .

The anionic surfactants include, for example, alkyl sulfonates, alkylbenzene sulfonates, and alkyl phosphates, and the cationic surfactants include quaternary ammonium chloride, quaternary ammonium nitrate, and quaternary ammonium sulfate. As the nonionic surfactant, poly (oxyethylene) alkylamine, poly (oxyethylene) alkyl ether, poly (oxyethylene) alkylphenyl ether, glycerin fatty acid ester, sorbitan fatty acid ester and the like can be used.

In the present invention, an inorganic filler may be blended with the base resin. Examples of the inorganic filler include fibrous materials such as alumina, silica, carbon black, calcium carbonate, magnesium carbonate, talc, clay, glass fiber, glass balloon, metal, iron oxide, and compounds containing iron oxide (ferrite, etc.), and granular materials. One or two or more of such materials and crushed materials are suitable.

By selecting and adjusting the type and amount of the inorganic filler, the specific gravity, hardness and the like of the blasting material can be selected and adjusted according to the properties of the object to be projected and the purpose of the blast treatment. The specific gravity is preferably 1.3 to 1.7, and the Rockwell hardness is preferably 100 to 130.

Of these, alumina, silica and glass fibers have high hardness and are suitable for relatively strong blasting. Since calcium carbonate, magnesium carbonate, talc, and clay have low hardness, they are suitable for relatively soft blasting. Glass balloons are suitable for blending when reducing the specific gravity of the shot material. When carbon black is blended, it is possible to impart conductivity to the shot material. The particle size of these inorganic fillers is 5 to 5
It is preferably about 00 μm, particularly about 10 to 200 μm.

As the inorganic filler, alumina, silica, carbon black, calcium carbonate, magnesium carbonate,
Talc, clay, glass fiber, glass balloon, metal,
When a fibrous material, a granular material, a crushed material, or the like of iron oxide or a compound containing iron oxide (such as ferrite) is blended, the shot material can be adjusted to a suitable specific gravity. In addition, by blending spherical, crushed, or fibrous iron oxide or a compound containing iron oxide (such as ferrite), it is possible to prevent the generation of static electricity during the crushing step at the time of sizing the shot material and at the time of projection. In any case, polishing by blasting, coating film peeling, mold washability, and the like can be improved.

Further, pigments containing iron oxide or a compound containing iron oxide (such as ferrite), specifically, αFeOOH, β
FeOOH, γFeOOH, αFe ₂ O ₃ , γFe ₂ O
_By mixing ₃ , Fe ₃ O ₄ , MoFe ₂ O ₃ , Mo ₆ Fe ₂ O _3, etc., it is possible to impart a color to the blasting material and color-code it, which is advantageous in handling and managing products. It is.

The filler comprising a metal or a pigment containing iron oxide or a compound containing iron oxide (such as ferrite) has a particle size of 10 μm or less, particularly 5 μm or less, especially 1 μm or less.
For example, those having a thickness of 0.005 to 1 μm are preferable.

The amount of such an inorganic filler is 0.1 to 20 parts by weight, preferably 1 to 15 parts by weight, particularly preferably 3 to 10 parts by weight, based on 100 parts by weight of the base resin. If the amount of the inorganic filler is less than 0.1 part by weight, the surface of the projection cannot be sufficiently peeled off, and if the amount is more than 20 parts by weight, the peeling becomes too strong.

In particular, when a filler made of a metal or a pigment containing iron oxide or a compound containing iron oxide (such as ferrite) is blended as the inorganic filler, the amount of the filler varies depending on the purpose of the blending. However, it is preferably 10 parts by weight or less, particularly preferably 0.001 to 1 part by weight, based on 100 parts by weight of the base resin.

In the projectile of the present invention, an organic filler may be further blended in an amount of 50 parts by weight or less based on 100 parts by weight of the base resin. As the organic filler, one or more of cellulose, a cellulose derivative, α-cellulose, and wood flour are suitable.

By incorporating this organic filler, the toughness of the shot material can be increased. If the amount of the organic filler is more than 50 parts by weight, the particle strength of the blast material is too low. When the organic filler is blended, the above effect can be sufficiently obtained by blending 5 parts by weight or more, but it is particularly preferable to blend 10 to 40 parts by weight, especially 20 to 30 parts by weight.

The particles constituting the blasting material of the present invention may have a uniform composition, or may consist of an aggregate of particles having different compositions.

The blasting material of the present invention is obtained by crushing or pulverizing a lump or pellet of a base resin comprising a surfactant and, if necessary, the above-mentioned inorganic filler and organic filler by a crusher or a crusher. The size may be adjusted to a predetermined particle size. When a filler is mixed with the base resin, a coupling agent may be added as necessary. In addition, you may add the above-mentioned inorganic filler or organic filler at the time of this crushing or pulverization.

The lower limit of the particle diameter of the shot material is 200 μm or more, preferably 500 μm or more, and the upper limit is 5000 μm or less, preferably 3000 μm or less, more preferably 1000 μm or less.
m or less, particularly preferably 850 μm or less.

The blasting material of the present invention is suitable for blasting treatment for removing paint on resin products, especially resin products such as urethane. Examples of the coating include urethane coating and acrylic coating, but other coatings may be used. Specific examples of the resin product include an automobile bumper and a pleasure boat.

Since the blasting material of the present invention can be easily sized to an arbitrary particle size, the blasting material of the present invention falls within the above-mentioned particle size range according to its use, that is, the type and properties of the projecting object. It is preferable to adjust the particle size as appropriate, for example, for a target having a hard material or a thick coating,
A blasting material having a relatively large particle size, specifically, a particle size of 500 to 1
A projection material having a diameter of 500 μm, and a relatively small particle size for a high-quality product such as a projectile having a soft material or a thin coating film, a resin product, an electronic component or a molded product, specifically, a particle size of 150 It is desirable to use different shot materials so as to use 射 850 μm.

As a method of spraying the powder together with the gas flow for the blasting treatment, various blasting methods can be used, but a dry blasting method is most suitable. The dry blast method is as follows: (a) A gravity blast method in which powder is charged into a tank at a position higher than the nozzle, and the powder that has fallen into a discharge port provided at the bottom of the tank due to gravity is sprayed from the nozzle together with compressed gas. (B) A direct pressure blast method in which powder is sealed in a powder pressure feeding tank, compressed gas is fed into the tank, and powder discharged from a discharge port provided at the bottom of the tank is injected from a nozzle together with compressed gas. C) A siphon blast method in which the powder is charged into a tank located at a position lower than the nozzle, and the powder discharged from a discharge port provided at the bottom of the tank by the compressed gas suction is injected from the nozzle together with the compressed gas. However, any of these blasting methods can be used.

As the compressed gas, compressed air is usually used. The amount of the powder, the pressure of the compressed gas, and the injection speed for the blast treatment can be appropriately selected depending on the type of the powder used and the state of the adhered substance on the resin product surface.

The powder used for the blast treatment can be separated and recovered from the adhered substance by using a conventional post-treatment facility such as a cyclone, and can be reused.

[0038]

Example 1 80 parts by weight of melamine, 20 parts by weight of urea and 200 parts by weight of formaldehyde were mixed, adjusted to pH 9 to 10, heated, and reacted under reflux to obtain a melamine / urea resin. Was.

After drying, 1 part by weight of polyoxyethylene nonyl ether and a curing agent were added and cured by heating.
After pulverization and classification, a resin blast material having a particle size of 500 to 850 μm was obtained.

When this blasting material was projected together with the gas flow onto a plastic projecting object, and the polishing force and the surface condition of the projecting object were measured, the polishing force was extremely good. The amount of adhesion was also very small. No damage was observed on the plastic surface.

Comparative Example 1 A blasting material was manufactured in the same manner as in Example 1 except that polyoxyethylene nonyl ether was not added, and the same blasting was performed. Also, it was recognized that the amount of the attached fine powder was considerably larger than that in Example 1.

[0042]

As is clear from the above Examples and Comparative Examples, according to the present invention, a shot material suitable for blasting the surface of a resin product is provided. According to this projection material, the projection material and the fine powder hardly adhere to the surface of the resin product,
In addition, the attached matter can be efficiently peeled and removed without damaging the surface.

Claims (7)

[Claims] 1. A shot material comprising an antistatic agent. 2. The shot material according to claim 1, wherein the antistatic agent is a surfactant. 3. A blasting material according to claim 2, wherein the surfactant is an anionic surfactant, and the compounding amount thereof is 0.001 to 10 parts by weight based on 100 parts by weight of the base resin. . 4. A blasting material according to claim 2, wherein the surfactant is a cationic surfactant, and the amount thereof is 0.001 to 10 parts by weight based on 100 parts by weight of the base resin. . 5. The blasting material according to claim 2, wherein the surfactant is a nonionic surfactant, and the compounding amount thereof is 0.001 to 10 parts by weight based on 100 parts by weight of the base resin. . 6. The method according to claim 1, wherein the base resin comprises at least one of a melamine resin, a urea resin, a phenol resin, a ketone resin, an epoxy resin and a guanamine resin. Projection material characterized. 7. A blasting method comprising blasting the surface of a projection object using the blasting material according to claim 1. Description: