JP2013233491A - Masking material, masking method, and method of manufacturing coated member on which coating film is not partially formed - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a masking material having superior heat resistance and capable of being repeatedly used, a method of manufacturing such a masking material, and a masking method using such a masking material.SOLUTION: A masking part 3 of a masking material 1 containing a magnetic component has a circular shape. The masking part 3 has a central part 4 that is more recessed than a circumferential part 5. In the masking material 1, a radius r (unit: mm) of a circle of the masking part 3, a maximum depth d (unit: mm) of the recess of the central part 4 relative to the circumferential part 5, a magnetic flux density B (unit: T) obtained by the measurement at a position separated by 1 cm in a direction parallel to a central axis of the circle of the masking part from a position giving the maximum depth in the masking part 3, and Shore D hardness Hs of the masking material 1 satisfy all of expressions of 0.045≤B...(1), 5.5≤B/(d/r)...(2), and 42≤Hs≤60...(3).

Description

  The present invention relates to a masking material for masking a portion where paint is not desired to be applied during coating, a masking method using the masking material, and a method for manufacturing a coated member in which a coating film is not partially formed. It is.

  Conventionally, a masking tape is generally used for masking a portion where a paint is not desired to be applied during coating. The masking tape is composed of a tape base material, an adhesive layer, and a release paper. When the masking tape is used, the release paper is peeled off, and the masking tape is applied to the masked portion using the adhesive force of the exposed adhesive layer. Then, it is peeled off from the masked portion after painting and discarded.

  In such a masking tape, both the release paper and the coated masking tape become wastes to be discarded, which is a waste of resources. Also, if the masking tape that has been applied once is peeled off and then reapplied, it may not be possible to reapply or the parting line may not appear clean due to a decrease in the adhesive strength of the adhesive layer. Furthermore, in order to stick by the adhesive strength of the pressure-sensitive adhesive layer, a desired adhesive strength cannot be obtained unless the oil content in the masked portion is removed.

  On the other hand, Patent Document 1 proposes to use a sheet containing magnetic powder as a masking sheet. According to such a masking sheet, it is possible to save the masking work by using magnetic force.

  Patent Document 2 proposes a means that enables the film thickness control of an object to be coated by changing the effective area of an electrode in electrodeposition coating.

Japanese Patent Laid-Open No. 61-257259 JP 11-152599 A

  However, the masking sheet disclosed in Document 1 is a soft resin in which the main component of the resin is soft and the soft resin component is microscopically deformed so as to follow the surface of the masked portion of the object to be coated. The intermolecular force generated between the component and the masked part prevents the paint from entering the masked part. That is, the main factor that brings about the masking function in the masking sheets disclosed in these documents is the adhesive force, and the magnetic powder contained in the masking sheet is the minimum pressure required to generate this adhesive force. It is only for granting.

  For this reason, when used in a harsh coating environment, specifically, in an environment where the coating method is immersion in paint or the baking temperature is high, the amount of deformation of the resin component increases as the number of uses increases. Or the degree of alteration of the resin component increases. For this reason, when it is repeatedly used in such a harsh coating environment, the resin component cannot generate sufficient adhesive force, and the masking function of the masking sheet is lost.

  Further, the means disclosed in Document 2 is a part where the thickness of the coating film is thin or the part where the coating film is not desired to be formed, that is, the area where the masking is desired and the surrounding area, considering the wraparound of the lines of electric force. The controllability of the film thickness is significantly reduced. For this reason, it is technically difficult to control the shape of the masked surface, for example, to perform masking in a spot manner.

  The present invention has been made in view of such a situation, and has a masking material having excellent heat resistance and an excellent masking function even in repeated use, and a masking method and a partial method using the masking material. It aims at providing the manufacturing method of the coating member in which the coating film is not formed in this.

  As a result of studies by the present inventors in order to achieve the above object, the masking portion is formed into a specific shape on the assumption that the magnetic characteristics and mechanical properties of the masking material are within a predetermined range. By controlling the contact surface pressure distribution (hereinafter also referred to as “surface pressure distribution”) to the masked part in the mask so that the contact surface pressure in the vicinity of the circumferential part of the masking part is increased, the coating environment is harsh. We obtained new knowledge that a masking material that maintains an excellent masking function can be obtained even when painting in that environment is repeated.

The present invention completed based on such knowledge is, firstly, a masking material used for an object to be heat-treated, which has a high Curie temperature higher than the heating temperature in the heat treatment. The masking portion of the masking material, which is composed of a mixture including a magnetic component made of a magnetic material and a resin component, is disposed opposite to the masked portion of the object to be coated when used, viewed from the masked portion side. The shape is a circle, and the masking part has a center part recessed from the circumference part, the radius r (unit: mm) of the circle of the masking part, the circumference of the recess of the center part of the masking part Measured at a position 1 cm away from the position at which the maximum depth d (unit: mm) with respect to the part is given, and the position along the center axis of the circle of the masking part. The resulting magnetic flux density B (unit: T), and a Shore D hardness Hs of the masking material is a masking material characterized by satisfying all of the following formulas (1) to (3) (Invention 1).
0.045 ≦ B (1)
5.5 ≦ B ² / (d / r) ² (2)
42 ≦ Hs ≦ 60 (3)

  The masking material according to the first aspect of the present invention has a contact pressure near the circumference of the masking portion that is higher than the contact pressure at the center, and has a contact pressure distribution in which the contact pressure is in an appropriate range. Even after repeated use, an excellent masking function can be maintained.

In the said invention (invention 1), the said circumferential part and the inner peripheral side of the said masking part may comprise the collar part which protrudes from the outer surface of the said masking material (invention 2).
In this case, since the heel portion is deformed so as to follow the masked portion of the object to be coated, the masking function of the masking material is further enhanced.

In the said invention (invention 1 and 2), it is preferable that the independent Shore D hardness of the said resin component which comprises the said masking material is 40-60 (invention 3).
In this case, it becomes easy for the masking material to satisfy the above formula (3) regardless of the type of the magnetic component.

  In the said invention (invention 1 to 3), the said resin component consists of 1 type, or 2 or more types chosen from the thermoplastic resin which has melting | fusing point higher than the heating temperature in the said thermosetting resin and rubber | gum, and the said heat processing. Is preferred (Invention 4).

  In the said invention (invention 4), it is still more preferable that the single melting point of the thermoplastic resin of the said resin component is 160 degreeC or more (invention 5).

  Since the resin component has the material characteristics according to Inventions 4 and / or 5, it is stably avoided that the masking material is greatly deformed when heated.

In the above inventions (Inventions 1 to 5), the masked portion of the object to be coated has a through hole, and the masking portion has a central portion that protrudes so as to be inserted into the through hole when used. (Invention 6).
By having such a protrusion, it becomes easy to determine the mounting position of the masking material on the masked portion.

In the said invention (invention 1-6), the said to-be-coated body may be given a coating process prior to the said heat processing (invention 7).
The masking material according to the above inventions (Inventions 1 to 6) maintains the magnetic force even when the heat treatment is performed. Therefore, the paint applied to a portion other than the masked portion of the object to be coated by the coating treatment performed before the heat treatment. This component is prevented from entering the masked portion during the heat treatment.

In the said invention (invention 7), the coating material used for the said coating process may be an electrodeposition coating liquid (invention 8).
When the paint used in the coating process is an electrodeposition coating liquid, it is easier for the paint components to enter the masked part during the coating process than the non-electrodeposition type paint, and the heating temperature after the coating process is higher. Although it tends to be high, even in such a case, it is possible to suppress the penetration of the paint into the masked portion and make the parting line unclear, that is, maintain the masking function. .

In the above inventions (Inventions 1 to 8), the object to be coated may be a vehicle body (Invention 9).
When the object to be coated is a vehicle body, the above electrodeposition coating liquid is often used. Even in such a case, the masking function can be appropriately maintained.

A second aspect of the present invention is the masking material according to the above inventions (Inventions 1 to 9), wherein the center of the masked portion of the object to be coated made of a ferromagnetic material is close to the center of the masking portion of the masking material. The masking method is characterized in that the masking material is placed on the object to be coated by the magnetic force (Invention 10).
The masking material according to the present invention is attached to an object to be coated by a magnetic force, and this magnetic force hardly changes even in repeated use. Therefore, even when the masking material according to the present invention is repeatedly used, the feeling that the worker receives and wears is less likely to change. Therefore, if the masking method according to the present invention is employed, the work stability in the entire coating process is increased, and process defects are less likely to occur.

Thirdly, the present invention is a method for producing a coated member having a portion where a coating film is not formed, and the masking material according to the above inventions (Inventions 1 to 9) is used as a masking material for a coating object made of a ferromagnetic material. A mounting step in which the masking material is attached to the object to be coated by the magnetic force, and the object to be coated on which the masking material is mounted in the mounting step. A dipping step in which the coating material is adhered to the object to be coated, a heating step in which the coating object to which the coating material is adhered is heated to form a coating film on the surface of the object to be coated, and the heating step The masking material is removed from the object to be coated, and a removal member for obtaining a painted member having a portion where the coating film is not formed on the portion where the masking material is attached is obtained. A method for manufacturing a coated member characterized by comprising a flop (invention 11).
Since the masking material according to the present invention maintains the magnetic force even when the heat treatment is performed, the masked portion set by covering a part of the surface of the object to be coated based on the magnetic force of the masking material is applied to the coating treatment and the heat treatment. It is possible to prevent the paint component from entering the masked portion. For this reason, it is hard to produce the malfunction that a parting line becomes unclear when a masking material is removed.

The masking material used in the mounting step in the invention (Invention 11) may be used in at least one heating step (Invention 12).
Since the masking material according to the present invention maintains the magnetic force even when heat treatment is performed, the masking function can be satisfactorily maintained even after repeated use.

  The masking material according to the present invention has an excellent masking function and can be used repeatedly even in a severe coating environment in which the object to be coated is immersed in the paint and further heated. Further, according to the masking method of the present invention, it is possible to repeatedly perform masking using the above masking material. Furthermore, according to the manufacturing method of the coating member which concerns on this invention, the coating member which has a part in which the coating is not given partially can be manufactured stably and cheaply.

It is a figure which shows notionally the cross section (a) and front shape (b) in the surface containing the central axis of the main-body part in the masking material which concerns on one Embodiment of this invention. It is a figure which shows notionally the cross section (a) and front shape (b) in the surface containing the central axis of the main-body part in the modification of the masking material which concerns on one Embodiment of this invention. It is a figure which shows notionally the cross section in the surface containing the central axis of the main-body part in another modification (when a masking part has a processus | protrusion) of the other masking material which concerns on one Embodiment of this invention. The cross section in the surface containing the central axis of the main-body part in another another modification of the masking material which concerns on one Embodiment of this invention (when it has a processus | protrusion on the opposite side of the end surface in which the masking part was provided) It is a figure shown conceptually

Hereinafter, embodiments of the present invention will be described.
1. Masking Material As shown in FIG. 1, a masking material 1 according to this embodiment includes a main body 2 having a cylindrical shape and a side facing the masked portion of the object to be coated when used in the main body 2 (the lower surface in FIG. 1). Side) and a masking portion 3 provided at the end.

(1) Composition The masking material 1 is comprised from the mixture containing the magnetic component and resin-type component which consist of a ferromagnetic material which has a Curie temperature higher than the heating temperature in the heat processing mentioned later. In a preferred embodiment, the resin component is composed of one or more selected from thermosetting resins and rubbers and thermoplastic resins having a melting point higher than the heating temperature in the heat treatment (hereinafter referred to as composition on this composition). Is also referred to as “basic configuration”.)

  Since the masking material 1 has such a basic configuration, the fluidity of the resin component contained in the masking material 1 is sufficiently low even in the environment of the heating temperature in the heat treatment. Therefore, the initial shape of the masking material 1 cannot be maintained through the painting process. Further, since the Curie temperature is higher than the heating temperature of the heat treatment, the masking function is not significantly lowered by the heat treatment.

The masking material 1 is parallel to the central axis of the circle of the masking part 3 from the position where the end surface of the object to be coated facing the masked part (that is, the end face on the masking part 3 side) is provided with the most concave portion. The magnetic flux density B measured at a position 1 cm away in the direction satisfies the following formula (A), and the following formula (B) is satisfied for the Shore D hardness Hs.
0.045 ≦ B (A)
42 ≦ Hs ≦ 60 (B)

  The masking material 1 has a basic configuration, satisfies the above formulas (A) and (B), and further satisfies the formula (C) described later, thereby realizing an excellent masking function even during repeated use. The

  The specific composition of the masking material 1 having the basic configuration is arbitrary as long as the above formulas (A) and (B) are satisfied.

  When the resin component includes a thermoplastic resin, the type may be appropriately selected in consideration of the heating temperature in the above heat treatment. Examples of suitable thermoplastic resins for the resin component include nylon 4, nylon 6, nylon 46, nylon 66, nylon 610, nylon 69, nylon 612, nylon 1212, nylon 11, nylon 12, nylon MXD6, nylon 6T and the like. Polyamide resin, polyimide resin, polyamideimide resin, polyester resin, polyethersulfone resin, polyetherimide resin, polyphenylene ether resin, polybenzimidazole resin, polybenzoxazole resin, polyphenylene sulfide resin, polyether ether ketone resin, etc. One kind can be used alone, or two or more kinds can be mixed and used.

  The thermoplastic resin according to the resin component may be a thermoplastic elastomer. Examples of such materials are olefin elastomers such as ethylene-propylene copolymer (EPR) and ethylene-propylene-diene copolymer (EPDM), and styrene such as SBR made of a copolymer of styrene and butadiene. -Based elastomers, silicon-based elastomers, nitrile-based elastomers, butadiene-based elastomers, urethane-based elastomers, nylon-based elastomers, ester-based elastomers, fluorine-based elastomers, and reactive sites (double bonds, anhydrous carboxyl groups, etc.) are introduced into these elastomers. Modified products and the like. These may be used alone or in combination of two or more.

  Among them, ester elastomers (polyester elastomers) that are excellent in balance of moldability, heat resistance, and flexibility are preferable, and polyester elastomers that are block copolymers having a hard segment and a soft segment are more preferable. Particularly preferred is a polyester elastomer in which is a polyester and the soft segment is a polyether. Specific examples of such a preferable polyester elastomer include a perprene series manufactured by Toyobo Co., Ltd. and a hytrel series manufactured by Toray DuPont.

  When the resin component contains a thermoplastic resin, the melting point of the thermoplastic resin alone (or a mixture thereof when the thermoplastic resin is composed of a plurality of resin materials) is preferably 160 ° C. or higher. For example, when the processing temperature is 160 ° C. or higher, if the melting point is 160 ° C. or higher, the masking material 1 is stably prevented from being greatly deformed even when exposed to a high temperature environment in the heat treatment. That is, it can be used repeatedly.

  When the resin component contains a thermosetting resin, known resins such as epoxy resins, polyurethanes, phenol resins, diallyl phthalate resins, unsaturated polyester resins, urea resins, melamine resins, silicone resins, polyimide resins and allyl ester resins One type or two or more types of thermosetting resin materials may be used.

  When the resin component contains rubber, natural rubber, synthetic isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), chloroprene rubber (CR), acrylonitrile-butadiene copolymer rubber (NBR) One or more known rubber materials such as butyl rubber (IIR), halogenated butyl rubber, urethane rubber, silicone rubber, fluorine rubber and polysulfide rubber may be used.

In the case where the resin component is made of a plurality of types of materials, the content ratio of each material is arbitrary.
The single Shore D hardness of the resin component is preferably 40-60. By having this degree of hardness, it becomes easy for the masking material 1 to satisfy the above formula (B) regardless of the type of magnetic component.

  Examples of the material constituting the magnetic component contained in the masking material 1 include, for example, metals such as iron, nickel, cobalt, alloys thereof (for example, stainless steel) or oxides, strontium ferrite, barium ferrite, manganese zinc ferrite, nickel. Ferromagnetic materials such as ferrites such as zinc ferrite and copper zinc ferrites, alnicos such as aluminum-nickel-cobalt alloys, and rare earths such as rare earth-transition metals (eg, SmCo, SmFeN, NbFeB) Is mentioned. Among these, from the viewpoint of easy control of the magnetic force, a ferrite type is preferable, and among them, strontium ferrite and barium ferrite are more preferable.

  The shape of the magnetic component is preferably a powder shape. In the case of a powder shape, the particle size is preferably 0.1 to 100 μm, particularly preferably 0.5 to 20 μm, and further preferably 0.5 to 3 μm.

  The content of the magnetic component contained in the masking material 1 is preferably 300 to 800 parts by mass, and preferably 400 to 700 parts by mass with respect to 100 parts by mass of the resin component constituting the masking material 1. Particularly preferred is 500 to 600 parts by mass. If the content of the magnetic component is excessively low, it may be difficult to satisfy the above formula (A). If the content of the magnetic component is excessively high, the above formula (B) may be satisfied. There is concern that it will be difficult.

  The masking material 1 may contain additives such as a dispersant as the other components in addition to the resin component and the magnetic component. Further, as one of the other components, a nonmagnetic material such as talc or kaolin may be contained for the purpose of adjusting the hardness. However, the content of such other components is preferably about 15% by mass with respect to the entire masking material 1 from the viewpoint of stably satisfying the above formulas (A) and (B).

(2) Shape As an example of the present embodiment, the height h of the masking material 1 shown in FIG. 1a is preferably 0.5 to 50 mm, and particularly preferably 1.0 to 30 mm. When the height h of the masking material 1 is less than 0.5 mm, the strength of the masking material 1 may be insufficient, and the masking material 1 may be easily deformed in the heat treatment. Further, since the total amount of the magnetic component is reduced, the magnetic pole strength (residual magnetic density) of the masking material 1 is lowered, and the possibility that it is difficult to satisfy the above formula (A) increases. On the other hand, when the height h of the masking material 1 exceeds 50 mm, the masking material 1 becomes unnecessarily thick and the material cost increases. In addition, the possibility that the masking material 1 falls off due to its own weight during the painting process or due to a collision with another member increases.

  As an example of this embodiment, as shown in FIG. 1B, the masking portion 3 of the masking material 1 is based on the shape of the main body portion 2 and is a shape seen from the direction along the central axis 6 of the main body portion 2 (that is, The shape obtained by projecting the masking portion 3 onto a plane with the central axis 6 of the main body 2 as a normal line, and the projection shape thus obtained is also referred to as a “front shape” hereinafter. The center 7 of the circle formed by the front shape and the central portion 4 which is the vicinity thereof are recessed more than the circumference 8 of the circle formed by the front shape and the peripheral portion 5 which is the vicinity thereof. . In other words, the circumferential portion 5 of the masking portion 3 protrudes from the end portion of the main body portion 2 in a direction along the central axis 6 of the main body portion 2. Therefore, the most concave portion of the masking portion 3 is located on the dividing surface of the main body portion 2 and the masking portion 3. For example, in FIG. 1B, the center 7 of the circle is the most concave portion.

  Although the maximum depth d (unit: mm, hereinafter also referred to as “maximum depth d”) with respect to the circumferential portion 5 of the recess of the central portion 4 of the masking portion is not limited, it is usually sufficiently larger than the thickness of the main body portion 2. Thin, for example, 0.1 mm or more and 3 mm or less. For example, in FIG. 1B, since the center 7 of the circle is the most concave portion, the maximum depth d is along the central axis 6 between the center 7 of the circle and the circumference 8 as shown in FIG. The distance in the direction.

  The single dimension of the maximum depth d is not particularly limited, but as will be described later, the radius of the circle forming the front shape of the masking portion 3, which is a geometric factor quantifying the degree of depression of the masking portion 3 in a dimensionless manner. The ratio r / d of the recess of the masking portion 3 to r (unit: mm, hereinafter abbreviated as “radius r”) is a specific relationship with the magnetic properties of the masking material 1 (the following formula (C)) It is required to satisfy.

  Since the masking portion 3 has such a shape feature, the masking material 1 arranged so as to face the substantially flat masked portion at the time of use has the circumferential portion 5 in contact with the masked portion, and the central portion 4 is Mounted without touching the masked part.

  The masking part 3 of the masking material 1 according to the present embodiment has a circular arc and a shape obtained when the masking part 3 is cut along a plane including the central axis 6 of the main body 2 (hereinafter referred to as “cross-sectional shape”). Although it is the shape which cut out the rectangle with the shape made from a string, it is not limited to this. Instead of the arc, a parabola having a vertex at the central portion 4 may be used, or a triangle having one of the vertices at the central portion 4 may be used. It may be a shape in which the inclination with respect to the normal plane is gentle. Since the masking material 1 according to the present embodiment obtains an excellent masking function by increasing the contact surface pressure at the circumferential portion 5, the cross-sectional shape of the masking portion 3 is that of the masking portion 3 of the masking material 1 according to the present embodiment. As described above, it is preferable that the shape is such that the inclination with respect to a plane having the central axis of the main body 2 as a normal line becomes gentler toward the apex at the central portion 4.

  Note that the masking portion 3 of the masking material 1 according to the present embodiment is formed so that the cross-sectional shape in any cross section including the central axis of the main body 2 is equal. It is preferable to have such a shape because variations in the masking function of the masking material 1 are reduced. Here, the fact that the cross-sectional shape in any cross section including the central axis of the main body 2 is equal also indicates that the front shape of the masking portion 3 is a circle. When the front shape deviates greatly from the circle, for example, has a star shape, the contact state in the circumferential direction changes according to the shape, and thus the possibility of variation in the masking function increases. .

  In the masking material 1 according to the present embodiment, the front shape of the main body portion 2 and the front shape of the masking portion 3 are the same, but they may not be the same and may have a similar relationship with a common center. In that case, the magnitude relationship between the two shapes is arbitrary. The front shape of the main body 2 may be larger than the front shape of the masking portion 3, or the front shape of the masking portion 3 may be larger than the front shape of the main body 2.

  The latter case is conceptually shown in FIG. In FIG. 2, the donut-shaped portion that does not overlap the front shape of the main body 2 in the front shape of the masking portion 3, that is, the circumferential portion 5 of the masking portion 3 and its inner peripheral side are The flange portion 21 protrudes outward from the outer surface 9 in the vicinity of the end portion on the side facing the masking portion. When the thickness of the flange portion 21 is equal to or less than a certain thickness, the flange portion 21 is deformed so as to follow the masked portion during use. For this reason, a force to recover from this deformation is generated in the heel portion 21, which acts to press the masked portion. That is, the collar portion 21 generates a masking function by an action different from the above-described masking function that is generated when a pressure force based on the magnetic force of the masking material 1 directly acts on the masking portion 3. Therefore, it is preferable that the masking portion 3 has the flange portion 21 because the masking function of the masking material 1 is enhanced.

The degree of the masking function provided by the heel portion 21 can be adjusted by the material (elastic modulus and the like) of the heel portion 21 and the shape of the heel portion 21. If an example is given about the range of the shape of the collar part 21, the maximum thickness of the collar part 21 is about 3 mm at the maximum, and the protrusion length D1 is about 10 to 75% of the outer diameter D2 of the main body part 2.
In addition, when the masking part 3 has the flange part 21, the area | region which receives and directly deform | transforms the pressurizing force based on the magnetic force of the main-body part 2 and the area | region slightly inside from the flange part 21 and this part of the masking part 3 Become.

Subsequently, another modification of the masking material according to the present embodiment will be described with reference to FIGS.
When the masked portion 30 of the object to be coated on which the masking material 1 is opposed to each other has a through hole 31, the protrusion protrudes to the extent that it is inserted into the through hole 31 when used as shown in FIG. The masking part 3 may have 10 in the center part. Having such a configuration is preferable because the mounting position of the masking material 1 can be determined using the projection 10 described above.

  As shown in FIG. 4, a gripping protrusion 11 for an operator to grip the masking material 1 may be provided on the masking material 1 on the side opposite to the end surface where the masking portion 3 of the main body 2 is provided. . When the gripping projection 11 is provided, the operator can easily attach and detach the masking material 1 and work stability is improved.

(3) Relationship between magnetic characteristics, mechanical characteristics, shape, and masking function The masking portion 3 of the masking material 1 according to the present embodiment has a radius r (unit: mm) and a maximum depth d that are masked of the object to be coated. Magnetic flux density obtained by measuring the surface facing the portion at a position 1 cm away from the most recessed portion in the direction along the center axis of the circle of the masking portion 3 (ie, from the position giving the maximum depth d in the masking portion 3) , A magnetic flux density obtained by measuring at a position 1 cm apart in the direction along the central axis of the main body 2, and hereinafter also referred to as “1 cm magnetic flux density”) The following formula including B (unit: T) ( C) is satisfied.
5.5 ≦ B ² / (d / r) ² (C)

  As described above, the masking material 1 according to this embodiment is attached to the masked portion of the object to be coated made of a ferromagnetic material by the magnetic force resulting from the magnetic component contained in the masking material 1. At this time, as described above, the cross-sectional shape of the masking portion 3 has a shape in which the circumferential portion 5 protrudes to the masked member side with respect to the central portion 4, so that the circumferential portion 5 preferentially contacts the masked portion. To do. In this contact state, a magnetic force (maximum depth) based on a magnetic component in the main body portion 2 of the masking material 1 in which the circumferential portion 5 protruding with the thickness of the maximum depth d is separated from the masked portion by the distance of the maximum depth d. Since the thickness d can be made sufficiently smaller than the thickness of the main body 2, it can be considered to be in a state of being in contact while being pressed by a magnetic force based on the magnetic component of the masking material 1.

  Since the contact surface pressure at the circumferential portion 5 varies depending on the contact state between the masking material 1 and the masked portion, it is not easy to quantitatively evaluate the contact surface pressure. If the pressure F is increased, it may be considered that the contact surface pressure also increases. Therefore, the degree of the masking function can be evaluated by the magnitude of the applied pressure F.

This pressure F is generated when the ferromagnetic material in the masked portion is magnetized by the magnetic field produced by the masking material 1. Here, since the maximum depth d forming the distance between the masked portion and the main body portion 2 can be made sufficiently smaller than the radius r, the applied pressure F is proportional to the area of B ² and the masking portion 3 (πr ² ). Further, in the shape of the masking material 1 according to the present embodiment, the applied pressure F is approximately inversely proportional to the square of the maximum depth d. For this reason, the following relationship is derived with respect to the applied pressure F.
F∝B ² · (πr ² ) / d ² (D)
When the right side of the above formula (D) is transformed, a formula including the right side of the above formula (C) is derived.

Therefore, the degree of the masking function can be quantitatively evaluated based on the value of the right side of the above formula (C) (hereinafter also referred to as “seal index”).
As a result of studies by the present inventors, it has been clarified that a masking material 1 exhibiting an excellent masking function even in repeated use can be obtained when the seal index is 5.5 or more.

  Here, in order to quantitatively evaluate the degree of the masking function by the seal index, there are preconditions on the shape, magnetic characteristics, and mechanical characteristics of the masking material 1.

  First, as a precondition regarding the shape, the maximum depth d is greater than 0 mm. When the maximum depth d is 0 mm, portions other than the circumferential portion 5 in the masking portion 3 also come into contact with the masked portion, and a high contact surface pressure cannot be realized.

  As a precondition regarding the magnetic characteristics, the masking material 1 needs to have a high 1 cm magnetic flux density B to some extent. Although the lower limit varies depending on the material of the object to be coated, etc., from the viewpoint that the evaluation by the seal index can be stably performed when the steel sheet, which is a generally used ferromagnetic material, is the object to be coated, The 1 cm magnetic flux density B is 0.45 T or more as shown in the above formula (A). From the viewpoint of enhancing the masking function of the masking material 1, no upper limit is set for the 1 cm magnetic flux density B. However, when a ferromagnetic material having a particularly high coercive force is employed as the magnetic component constituting the masking material 1 and the 1 cm magnetic flux density B is excessively high, the material cost increases. Alternatively, when a 1 cm magnetic flux density B is excessively high using a general ferromagnetic material having a coercive force as a magnetic component, the content of the resin component is relatively decreased, and the mechanical properties of the masking material 1 are deteriorated. Let Therefore, in practice, it is preferable that the 1 cm magnetic flux density B has an upper limit of about 3T.

  As a precondition regarding the mechanical characteristics, the masking material 1 according to the present embodiment satisfies the above formula (B). Since the masking material 1 according to the present embodiment deforms the circumferential portion 5 with magnetic force to exert a masking function, when the Shore D hardness Hs of the masking material 1 is excessively high, the masked portion is sealed. Further, the circumferential portion 5 cannot be deformed, and the masking material 1 cannot sufficiently exhibit the masking function. On the other hand, when the Shore D hardness Hs of the masking material 1 is excessively low, the entire masking portion 3 is easily deformed, so that not only the circumferential portion 5 but also the region close to the central portion 4 is in contact with the masked portion. End up. For this reason, even if the applied pressure F is the same, the substantial contact surface pressure between the masking portion 3 and the masked portion decreases. In this case, it is clear that the masking function of the masking material 1 is lowered. Therefore, upper and lower limits are set for the Shore D hardness Hs of the masking material 1 according to the present embodiment, and the relationship is as shown in the above formula (B).

2. Manufacturing method of masking material The manufacturing method of the masking material 1 which concerns on this embodiment is not limited. It is appropriately set according to the composition. A preferable production method when the resin component is made of a thermoplastic resin is injection molding. A preferable production method in the case where the resin component is made of a thermosetting resin is extrusion molding. When the resin component is composed of a plurality of types of resins, the viscosity of the material as the main component is reduced, and the powder as a main component, the powder composed of the material related to the other resin component, and the magnetic component It is preferable to prepare a slurry-like composition containing, and perform a process of curing the composition after molding.

3. Method for Using Masking Material Masking material 1 according to the present embodiment is used for an object to be coated that is subjected to heat treatment. Specifically, when the masking portion 3 of the masking material 1 is disposed so as to cover the masked portion of the object to be coated, the masking material 1 is attached to the masked portion by the magnetic force of the masking material 1.
Even if the material to be coated with the masking material 1 is subjected to heat treatment, the Curie temperature of the magnetic component contained in the masking material 1 is higher than the heating temperature related to the heat treatment, so that the magnetic force is high. There is no significant attenuation.
When this heat treatment is completed, the masking material 1 can be easily removed from the material to be coated by hand.

  Here, prior to performing a heat treatment on the material to be coated, a coating process may be performed on the object to be coated on which the masking material 1 is mounted. Since the masking material according to the present embodiment maintains the magnetic force even when the heat treatment is performed, the paint applied to the portion other than the masked portion of the object to be coated by the paint treatment performed before the heat treatment is performed during the heat treatment. Intrusion into the masked portion is suppressed.

  The details of the above-described coating process are not limited, and may be a process of immersing the object to be coated on which the masking material 1 is mounted in the paint, or a process of spraying the paint with a spray. Further, when depositing the components of the paint on the surface of the object to be coated, a surface treatment by an electrolytic method may be performed on the material to be coated immersed in the paint. In the present embodiment, “paint” means a liquid composition used for the coating treatment, and may contain a coloring material composed of a dye and / or a pigment, or may not contain a coloring pigment. Therefore, the surface treatment by the electrolytic method for depositing the component of the electrodeposition liquid as the undercoat of color coating on the object to be coated and the treatment for depositing the clear coat formed on the colored coating film are also included in this embodiment. It is included in the painting process. Furthermore, it is used in the surface adjustment treatment performed as necessary to improve the adhesion between the coating layer and the object to be coated, specifically, etching treatment, phosphate treatment, etc. The liquid composition for treatment is also included in the concept of “paint” in the present embodiment, and the surface conditioning treatment performed using such a liquid composition for treatment is also included in the concept of paint treatment in the present embodiment. Shall be.

  The masking material 1 that has been mounted on the material to be coated that has been subjected to the heat treatment may be mounted on the material to be coated again and subjected to the heat treatment. The masking material 1 according to this embodiment can maintain an excellent masking function even if such repeated use is made.

4). Method for Producing Paint Member An example of a method for producing a paint member in which a coating film is not partially formed using the masking material 1 according to this embodiment includes the following steps.

(1) Wearing step (masking method)
In the mounting step, the masking material 1 according to the above-described embodiment is arranged so that the masked portion of the object to be coated made of a ferromagnetic material is covered with the masking portion 3 of the masking material 1, and the masking material 1 is applied with its magnetic force. Attach to the object to be painted.

  At this time, the substantial contact area of the masking portion 3 with the masked portion becomes the circumferential portion 5, and the magnetic force by the main body portion 2 of the masking material 1 is applied to the circumferential portion 5. As a result, the constituent material of the masking material 1 in the circumferential portion 5 is deformed to seal the masked portion.

  Note that it is preferable to arrange the masked portion of the object to be coated so that the center of the masked portion is close to the center of the masking portion 3 of the masking material 1 because the masked portion is stably sealed.

(2) Immersion step In the immersion step, the object to be coated on which the masking material 1 is mounted in the mounting step is immersed in the paint, and the paint is attached to the object to be coated. Conditions such as the composition, temperature, and immersion time of the paint are appropriately set according to the coating method.

  Since the masking material 1 according to this embodiment has an excellent masking function, the coating method may be electrodeposition coating. In the case of electrodeposition coating (that is, when an electrodeposition coating liquid is used as a paint in the coating process), the coating substance is electrolyzed unlike coating by simply dipping in paint (hereinafter also referred to as “simple immersion coating”). Therefore, the immersion time in the paint is generally longer than that in simple immersion coating. In addition, since the masking material used for electrodeposition coating undergoes an electrochemical reaction in the immediate vicinity of the seal portion, the masking material is likely to be chemically altered. Therefore, the masking material used for electrodeposition coating is required to maintain a masking function superior to the masking material used for simple immersion coating, particularly sufficient masking function even during repeated use. The masking material 1 according to the present embodiment can sufficiently meet this requirement.

(3) Heating step (heat treatment)
In the heating step, the object to be coated, which has been subjected to the immersion step described above, is heated to form a coating film on the surface of the object to be coated. This heating temperature is determined by the composition of the paint and the coating method in the dipping step, but is generally about 120 ° C. to 160 ° C. in the case of simple immersion coating, and 180 in the case of electrodeposition coating. In some cases, the temperature may be about 200 ° C. or higher.

  In a preferable aspect according to the present embodiment, the masking material 1 used in at least one heating step is used in the mounting step. By passing through the heating step, the masking material 1 is exposed to a high temperature environment of usually 100 ° C. or higher, and in some cases about 180 ° C. or higher as described above. When the masking function of the masking material is brought about by the adhesiveness of the part in contact with the part to be masked, exposure to such a high temperature environment changes the physical and chemical characteristics of the contacted part. The adhesiveness is likely to be reduced. On the other hand, since the masking material 1 according to the present embodiment does not have adhesiveness as a main factor in generating the masking function, the characteristics are hardly deteriorated even when exposed to such a high temperature environment.

(4) Removal step In the removal step, the masking material 1 is removed from the object to be coated that has undergone the above heating step, and at least a part of the portion where the masking material 1 is mounted has a region where no coating film is formed. Get painted parts.

  In a preferred aspect of the manufacturing method according to the present embodiment, the masking material 1 removed in this removal step is used in a mounting step for another object to be coated. As described above, the masking material 1 according to the present embodiment hardly maintains a masking function even after being subjected to a heating step, and therefore can maintain an excellent masking function even when used repeatedly.

  EXAMPLES Hereinafter, although an Example etc. demonstrate this invention further more concretely, the scope of the present invention is not limited to these Examples etc.

(Examples 1-8 and Comparative Examples 2-8)
A masking material having the same shape as that shown in FIG. 2, that is, having a ridge portion, was molded by injection molding using a mixture of the resin-based material having the composition shown in Table 1 and a magnetic component. In addition, ratio (D1 / D2) with respect to the outer diameter D2 of the masking material of the protrusion length D1 of a collar part was 8.3%. The shape, magnetic properties and mechanical properties of the masking material are as shown in Table 1.

  Here, the 1 cm magnetic flux density measured as the magnetic property is a surface facing the masked portion of the object to be coated (ie, the surface including the masking portion in the masking material) using Toyo Technica Corp., 5080 type handy Gauss meter. Is a magnetic flux density obtained by measuring at a position 1 cm away from the most concave portion in a direction parallel to the central axis of the circle of the masking portion.

  The obtained masking material was disposed on a steel plate (SUS304, relative magnetic permeability: 1.4) having a through hole with a diameter of 5 mm so as to cover the through hole. At that time, the masking material was attached to the steel plate by the magnetic force of the masking material without any special pressurization.

(Comparative Example 1)
A conventional masking tape (manufactured by 3M, fine line masking tape 2800) was attached to a steel plate (SUS304, relative permeability: 1.4) using a 2 kg roller.

<Test Example 1> Immersion test Samples (masking material or steel plate with masking tape) prepared in the examples and comparative examples were immersed in a bath filled with an electrodeposition coating liquid (liquid temperature: 23 ° C.). A sample was taken out 10 minutes after the start of immersion, the masking material or masking tape was removed, and the presence or absence of adhesion of the electrodeposition liquid on the masked portion of the steel sheet was confirmed. The evaluation criteria are as follows.
○: No adhesion ×: Adhesion

<Test Example 2> Repeated immersion test For each masking material, the work related to Test Example 1 was repeated five times using different steel plates, and the masking material after the fifth time was evaluated, and the evaluation related to Test Example 1 was performed. It was confirmed whether it can be used. The evaluation criteria are as follows.
○: No adhesion even on the fifth steel plate, and reusable ×: Adhesion is observed on the fifth steel plate and cannot be reused

<Test Example 3> Heat resistance test Five cycles in which the samples (masking material or steel plate with masking tape) prepared in the examples and comparative examples were left in an environment of 180 ° C. for 5 hours and then left at 23 ° C. for 5 hours. After the repetition, the same immersion test as in Test Example 1 was performed. The evaluation criteria are as follows.
○: No adhesion ×: Adhesion

  The evaluation results are shown in Table 2.

  As shown in Table 2, the masking material having the basic configuration and satisfying the above formulas (A) to (C) gave good results for any of the immersion test, the immersion repetition test, and the heat resistance test. .

  The masking material of the present invention is suitably used for, for example, masking in a painting operation including a heating process of a steel plate for automobiles, or masking in an electrodeposition coating operation of a ground terminal portion of a vehicle body.

DESCRIPTION OF SYMBOLS 1 ... Masking material 2 ... Main-body part 3 ... Masking part 4 ... Center part 5 ... Circumference part 6 ... Center axis 7 ... Center 8 ... Circumference 9 ... Outer surface 10 ... Protrusion 11 ... Grasping protrusion 21 ... Gutter part 30 ... Masked part 31 ... through hole

Claims (12)

A masking material used for the object to be heat-treated,
It is composed of a mixture containing a magnetic component made of a ferromagnetic material having a Curie temperature higher than the heating temperature in the heat treatment and a resin component,
The masking portion of the masking material, which is a portion disposed opposite to the masked portion of the object to be coated at the time of use, has a circular shape when viewed from the masked portion side, and the masking portion is a central portion rather than a circumferential portion. Is recessed,
A radius r (unit: mm) of the circle of the masking portion, a maximum depth d (unit: mm) of the recess of the central portion of the masking portion with respect to the circumferential portion, and a position for giving the maximum depth in the masking portion The magnetic flux density B (unit: T) obtained by measuring at a position 1 cm away in the direction along the center axis of the circle of the masking part, and the Shore D hardness Hs of the masking material are represented by the following formulas (1) to (1): A masking material satisfying all of (3).
0.045 ≦ B (1)
5.5 ≦ B ² / (d / r) ² (2)
42 ≦ Hs ≦ 60 (3)   2. The masking material according to claim 1, wherein the circumferential portion of the masking portion and an inner peripheral side thereof form a flange portion protruding from an outer surface of the masking material.   The masking material according to claim 1 or 2, wherein a single Shore D hardness of the resin-based component constituting the masking material is 40 to 60.   The said resin component consists of 1 type (s) or 2 or more types chosen from the thermosetting resin and rubber | gum, and the thermoplastic resin which has melting | fusing point higher than the heating temperature in the said heat processing. The masking material described.   The masking material according to claim 4, wherein a single melting point of the thermoplastic resin of the resin component is 160 ° C. or more.   6. The masking portion of the object to be coated has a through hole, and the masking portion has a protrusion at the center thereof that protrudes to the extent that it is inserted into the through hole when in use. The masking material according to one item.   The masking material according to any one of claims 1 to 6, wherein a coating process is performed on the object to be coated prior to the heat treatment.   The masking material according to claim 7, wherein the paint used for the coating treatment is an electrodeposition coating liquid.   The masking material according to claim 1, wherein the object to be coated is a vehicle body.   The masking material according to any one of claims 1 to 9 is disposed so that the center of the masked portion of the object to be coated made of a ferromagnetic material is close to the center of the masking portion of the masking material, A masking method comprising attaching a masking material to the object to be coated by its magnetic force. A method for producing a painted member having a portion where a coating film is not formed,
The masking material according to any one of claims 1 to 9 is disposed so that a masked portion of a coated body made of a ferromagnetic material is covered with a masking portion of the masking material, and the masking material is A mounting step for mounting on the object by magnetic force;
Immersion step of immersing the object to be coated, to which the masking material is attached in the attachment step, in a paint, and attaching the paint to the object to be coated;
A heating step in which the coating body to which the paint is attached is heated to form a coating film on the surface of the coating body, and the masking material is removed from the coating body that has undergone the heating step, and a portion on which the masking material is mounted The manufacturing method of the coating member characterized by including the removal step which obtains the coating member which has a part in which the coating film is not formed in this.   The method for manufacturing a painted member according to claim 11, wherein the masking material used in the mounting step is used in at least one heating step.

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