JP2007144561A - Blast material and blast processing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem caused by resin component remaining on a metallic substrate in resin blast processing. <P>SOLUTION: A blast material contains mainly resin particles and a modified agent composed of mineral oil and/or fat component. Contents of the modified agent in the blast material is 0.1 to 10 wt.%, preferably, 0.5 to 2 wt.%. The blast processing method uses this blast material. Coexistence of the modified agent prevents a residual resin component from adhering on the surface of the metallic substrate. Therefore, the remaining resin component can be easily removed by cleaning and degreasing process after blasting process. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a projection material mainly composed of resin particles for blasting a member surface. In particular, the resin component derived from the projection material remaining on the surface of an object to be projected is easily obtained by degreasing after blasting. It relates to a projection material that can be removed. The present invention also relates to a blasting method using this projection material.

  Building materials such as aluminum sashes and fences, various automobile parts, home appliances such as refrigerators and TVs, or metal products such as steel furniture and office equipment are given rust prevention and durability. In order to do so, various paints are applied. As such a coating method, there are various coating methods such as direct spraying of a coating liquid, coating using electrostatic adsorption or electrodeposition, and powder coating without using a solvent, but in any case, In order to form a beautiful coating film that adheres firmly, the surface of the substrate on which the coating film is formed is sufficiently cleaned and roughened.

  Conventionally, this surface treatment is performed by the procedures of blast treatment, cleaning, degreasing treatment, and chemical conversion treatment, and then painting is performed.

  In addition, in the re-painting of defective products discharged from such a coating process, or in the re-painting for recycling of painted products, the coating film peeling process is performed by blasting, and then the cleaning, degreasing process, and chemical conversion process are performed. After the surface treatment is performed in the procedure of, repainting is performed.

Conventionally, a resin blasting process is known as a method capable of performing good coating film peeling or surface treatment without damaging the substrate as a blasting process as a surface treatment before coating peeling or coating ( For example, the following patent documents 1, 2, and 3). Resin blasting is a method in which a projection material made of resin particles is sprayed onto an object by high-speed processing with compressed air, and a coating film on the surface is peeled off or surface properties are adjusted.
JP 2003-290706 A Japanese Patent Laid-Open No. 2003-311210 JP 2002-79467 A

  However, after the resin blast treatment is performed on the metal base material, the resin component resulting from the resin particles of the projection material remains in close contact with the surface of the metal base material, and this residue is subsequently washed and degreased. It cannot be removed even by treatment, and becomes an inhibiting factor that hinders the chemical conversion treatment in the chemical conversion treatment step after the degreasing treatment.

  When a metal base material that has not been sufficiently subjected to chemical conversion treatment is coated, a coating film having excellent adhesion to the metal base material cannot be formed. Corrosion progresses at the coating interface due to the test and salt spray test, and causes defects such as coating film peeling.

  Resin components remaining on the surface of the metal substrate by resin blasting can be removed by performing an etching process that dissolves the surface of the metal substrate in the pre-painting process, or a treatment with a strong alkali or strong acid. However, it is not industrially preferable to perform such a treatment because the treatment steps and chemical costs for the treatment increase. Moreover, due to recent environmental problems, it is not preferable to use such chemicals that cause environmental pollution.

  Accordingly, an object of the present invention is to provide a projection material and a blasting method that can solve the problem of the resin component remaining on the metal substrate by the conventional resin blasting.

  The projection material of the present invention (claim 1) is characterized by comprising a modifier mainly composed of resin particles and comprising a mineral oil and / or an oil and fat component.

  The projection material according to claim 2 is characterized in that, in claim 1, the content of the modifier is 0.1 to 10% by weight.

  The projection material according to claim 3 is characterized in that, in claim 2, the content of the modifying agent is 0.5 to 2% by weight.

  According to a fourth aspect of the present invention, in the projection material according to any one of the first to third aspects, the modifier is mainly composed of mineral oil.

  The projection material according to claim 5 is characterized in that, in claim 4, the mineral oil is a paraffinic mineral oil.

  A projecting material according to a sixth aspect is characterized in that, in any one of the first to fifth aspects, the resin particles are particles of a thermosetting resin.

  The projection material according to claim 7 is the projection material according to claim 6, wherein the thermosetting resin is one or more selected from the group consisting of melamine resin, urea resin, phenol resin, ketone resin, epoxy resin and guanamine resin. It is characterized by that.

  The blasting method of the present invention (invention 8) is characterized in that the surface of the projection object is blasted by using the projection material according to any one of claims 1 to 7.

  A blasting method according to a ninth aspect is characterized in that, in the eighth aspect, the blasting process is a blasting process for peeling the coating film from the metal base material to which the coating has been applied.

  A blasting method according to a tenth aspect is the blasting method according to the eighth aspect, wherein the blasting process is a blasting process as a surface treatment before the coating of the metal base material.

  A blasting method according to an eleventh aspect is characterized in that, in any one of the eighth to tenth aspects, the projection is subjected to a degreasing process after the blasting process.

  As described above, the resin blasting process leaves a trace amount of resin component due to the resin particles on the surface of the metal substrate, but the projection material of the present invention contains a modifier composed of mineral oil and / or oil and fat component. Therefore, the coexistence of the modifier prevents the residual resin component from sticking to the surface of the metal substrate. For this reason, this residual resin component can be easily removed by washing and degreasing after the blast treatment.

  Therefore, by using the projection material of the present invention, the inhibition of the chemical conversion treatment due to the residual resin component of the resin blast treatment is prevented, and a coating film with high adhesion is formed on the metal substrate by performing a good pre-treatment. You can get high quality painted products.

  In the present invention, the content of the modifier in the projection material is preferably 0.1 to 10% by weight, particularly 0.5 to 2% by weight (Claims 2 and 3).

  As the modifier, those mainly composed of mineral oil, particularly paraffinic mineral oil are preferred (claims 4 and 5).

  The resin particles as the main component of the projection material are preferably thermosetting resin particles (Claim 6). Examples of the thermosetting resin include melamine resin, urea resin, phenol resin, ketone resin, epoxy resin and One or more selected from the group consisting of guanamine resins are preferred (Claim 7).

  The blasting method of the present invention is a method for blasting the surface of an object to be projected using such a projection material of the present invention, and for blasting a coating film from a coated metal base material. It is suitable as a blast treatment method as a treatment or a surface treatment before painting of a metal substrate (claims 9 and 10).

  Since the projection material of the present invention is easily removed from the metal base material particularly by the degreasing treatment after the blast treatment, it is preferable to degrease the projection object after the blast treatment according to the present invention ( Claim 11).

  Hereinafter, embodiments of the projection material and the blasting method of the present invention will be described in detail.

  The projection material of the present invention is mainly composed of resin particles and contains a modifier composed of mineral oil and / or oil and fat components.

  As the resin particles that are the main component of the projection material of the present invention, particles made of a thermosetting resin are preferable. Examples of the thermosetting resin include melamine resin, urea resin, phenol resin, ketone resin, epoxy resin, and guanamine resin. 1 type or 2 types or more are preferable.

  However, the resin particles may be made of a thermoplastic resin. In this case, the thermoplastic resin may be one or two of polystyrene, unsaturated polyester, polyacrylonitrile, (meth) acrylic resin, polycarbonate and polypropylene. More than one species are suitable, but PET, nylon, polyethylene, vinyl chloride resin, AS resin, MS resin, ABS resin and the like can also be used.

  The resin particles constituting the projection material of the present invention may be composed of only one kind of each resin, or may be particles composed of a blend of the above resins. The resin particles may be made of a composite material obtained by mixing one or more of various inorganic or organic fillers with the above-mentioned resin as a base material.

  The resin particles made of melamine resin are particularly excellent in heat resistance and impact resistance. Resin particles made of urea resin are particularly excellent in impact resistance. Resin particles made of phenol resin are particularly excellent in heat resistance. Resin particles made of a ketone resin are particularly excellent in wear resistance. Resin particles made of an epoxy resin are particularly excellent in heat resistance and water resistance. Resin particles made of guanamine resin are particularly excellent in impact resistance. Therefore, it is preferable to selectively use resin particles according to the characteristics required for the projection material.

  The particle size (average particle size) of such resin particles is appropriately determined according to the purpose of use of the projection material, but the lower limit is 50 μm or more, preferably 100 μm or more, from the viewpoint of blasting efficiency, handling properties, etc. More preferably, it is 200 μm or more, and the upper limit is 5000 μm or less, preferably 3000 μm or less, more preferably 1500 μm or less, and particularly preferably 1000 μm or less.

  For example, for a projection object having a hard material or a thick coating film, resin particles having a relatively large particle diameter, specifically, resin particles having a particle diameter of 500 to 1500 μm are used. For projectiles, it is preferable to use resin particles having a relatively small particle size, specifically, resin particles having a particle size of 150 to 850 μm.

  In order to produce resin particles, for example, a resin lump or pellet obtained by adding a filler or the like to a thermosetting resin, if necessary, is crushed or crushed with a crusher or pulverizer, and sized to a predetermined particle size. That's fine. When blending a filler with the resin, a coupling agent may be added as necessary.

  The projection material of the present invention may contain two or more resin particles of different materials, or may contain two or more types of resin particles of different particle sizes.

  The modifier contained in the projection material of this invention consists of 1 type, or 2 or more types chosen from mineral oil and an oil-and-fat component.

  Examples of the mineral oil include paraffinic and other aliphatic hydrocarbons, cycloparaffinic and other alicyclic hydrocarbons, and naphthenic and other aromatic hydrocarbons. In the present invention, any of these mineral oils can be used. Although it can be used, paraffinic mineral oil is preferable because it is particularly excellent in oxidative stability and maintains stable properties over a long period of time.

  On the other hand, the oil and fat component may be animal or vegetable. The modifier is preferably derived from paraffinic fatty acids, but may be derived from olefinic fatty acids or acetylenic fatty acids.

  The modifier is preferably liquid at room temperature, and therefore the mineral oil as the modifier is preferably a paraffinic mineral oil having 5 to 19 carbon atoms. However, even a gel or solid mineral oil made of a mineral oil having 20 or more carbon atoms can be used.

  The modifier may be composed of one of the above-described mineral oil or fat component, or may be composed of two or more of mineral oil and / or fat component.

  If the content of the modifier in the projection material of the present invention is too small, the effects of the present invention due to the inclusion of the modifier cannot be sufficiently obtained, and if too large, the content of resin particles is relatively large. The function as a projection material is impaired by reducing the amount. Therefore, the content of the modifier in the projection material is preferably 0.1 to 10% by weight, particularly 0.5 to 2% by weight.

  The projection material of the present invention is mainly composed of resin particles, and this is contained in the projection material in an amount of about 70% by weight or more, and the modifier is preferably 0.1 to 10% by weight, particularly preferably 0.5 to 2 wt% may be included, and components other than the resin particles and the modifier may be included.

  The projection material of the present invention containing the resin particles and the modifier can be easily manufactured by adding and mixing a predetermined amount of the modifier to the resin particles. It can also be added and mixed at the time of crushing or crushing process or granulating process.

  The blasting method of the present invention can be carried out according to a conventional method except that such a projection material of the present invention is used.

Various blasting methods can be used as a method of spraying the projection material together with the gas flow for the blasting process, but the dry blasting method is optimal. For dry blasting,
(1) Gravity-type blasting method in which the projection material is introduced into a tank located higher than the nozzle, and the projection material dropped onto the discharge port provided at the bottom of the tank by gravity is injected from the nozzle together with the compressed gas;
(2) Direct pressure blasting method in which a projection material is enclosed in a pressure-feed tank, compressed gas is fed into the tank, and the projection material discharged from the discharge port provided at the bottom of the tank is injected from the nozzle together with the compressed gas.
(3) A siphon-type blasting method in which the projection material is introduced into a tank located below the nozzle, and the projection material discharged from the discharge port provided at the bottom of the tank by the suction of the compressed gas is injected from the nozzle together with the compressed gas,
Any of these blasting methods can be used.

  Usually compressed air is used as the compressed gas. The amount of the blasting material for blasting, the pressure of the compressed gas, and the injection speed can be appropriately selected according to the type of the blasting material used, the type of the projection object, the purpose of the blasting, and the like.

  The blasting material after being used for the blasting process can be separated and recovered from the release substance using a conventional post-processing equipment such as a cyclone and reused.

  In the blasting method of the present invention, the object to be projected is preferably one having a metal base material to which the residual resin component easily adheres in the resin blasting process. The metal base material is a metal such as aluminum or iron. Or what consists of an alloy containing these metals is mentioned.

  In particular, the present invention was formed on a metal substrate for blasting treatment for peeling a coating film from a coated metal substrate, that is, for a defective coating or a re-coating film for recycling. It is effective for a blasting process for peeling off the coating film and a blasting process as a surface treatment before the coating of the metal substrate.

  The residual resin component adheres to the metal substrate by performing the blasting treatment with the projection material of the present invention, and this residual resin component coexists with the modifier composed of mineral oil and / or fat and oil component. By doing so, it can be easily removed by degreasing after blasting and does not adversely affect the subsequent chemical conversion treatment.

  After the blast treatment according to the present invention, after air blowing, water washing (or hot water washing) or shower washing is performed, and then degreasing treatment is performed as necessary. Examples of the degreasing treatment include a method of spraying or dipping using a degreasing agent such as alkaline sodium silicate.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.

  In the following, a non-painted aluminum wheel was used as the projection object.

Example 1
In the present invention, paraffinic mineral oil (compressor oil) having about 10 carbon atoms as a modifier is added to and mixed with resin particles made of melamine resin having a particle size of 500 to 850 μm (average particle size of 750 μm) in the present invention. A projection material was prepared.

  Using this projection material, the aluminum wheel was blasted manually by a general direct pressure blasting apparatus. The nozzle used was a high-speed type with a diameter of 6.0 mm, the injection pressure was 0.5 MPa, the injection distance was about 100 mm, and the blasting time was about 20 seconds / spoke.

  After blasting, air blowing, washing with water, and spraying with an alkaline solvent-based degreasing agent was performed for degreasing.

  After this degreasing treatment, the presence or absence of the resin component remaining on the aluminum wheel was examined by high-sensitivity analysis using FT-IR (Fourier transform infrared spectrophotometer: manufactured by Thermo Electro), and the results are shown in Table 1.

When the resin component remains on the aluminum wheel, in this IR analysis, the vibration peak of the bond specific to the melamine resin and the vibration peak of the triazine ring is observed in the vicinity of 1560 cm ⁻¹ . The presence or absence can be confirmed. Further, the residual amount of the resin component can be quantitatively analyzed based on the intensity of the vibration peak.

Comparative Example 1
In Example 1, the aluminum wheel was blasted, washed and degreased in the same manner except that the compressor oil was not added to the projection material and the resin particles alone were blasted, and the FT-IR analysis was performed in the same manner. The results are shown in Table 1.

  From Table 1, it can be seen that according to the present invention, the problem of the residual resin component due to the resin blast treatment can be solved.

  In Example 1 and Comparative Example 1, when the aluminum wheel after blasting and degreasing was subjected to a coating treatment according to a conventional method, the one in Comparative Example 1 in which the resin component remained was a hot water test or salt water. Although the coating film peeled off in the spray test, there was no problem of coating film peeling in the case of Example 1 in which no resin component remained even when the hot water test or the salt spray test was performed.

Claims (11)

  A projection material comprising a resin particle as a main component and a modifier comprising a mineral oil and / or a fat component.   In Claim 1, Content of the said modifier is 0.1 to 10 weight%, The projection material characterized by the above-mentioned.   The projection material according to claim 2, wherein the content of the modifier is 0.5 to 2% by weight.   The projection material according to claim 1, wherein the modifier is mainly composed of mineral oil.   The projection material according to claim 4, wherein the mineral oil is a paraffinic mineral oil.   6. The projection material according to claim 1, wherein the resin particles are thermosetting resin particles.   In Claim 6, the said thermosetting resin is 1 type, or 2 or more types chosen from the group which consists of a melamine resin, a urea resin, a phenol resin, a ketone resin, an epoxy resin, and a guanamine resin, The projection material characterized by the above-mentioned.   A blasting method comprising blasting a surface of an object to be projected using the projection material according to claim 1.   9. The blasting method according to claim 8, wherein the blasting process is a blasting process for peeling a coating film from a coated metal base material.   9. The blasting method according to claim 8, wherein the blasting process is a blasting process as a surface process before the coating of the metal base material.   11. The blasting method according to claim 8, wherein the projection object is subjected to a degreasing process after a blasting process.