JPWO2015046494A1 - Masking material and masking method - Google Patents

Abstract

A first member (2) made of an elastic material and having a masking part (22) for contacting at least a part of the masked part, and a second member for detachably holding the first member (2) (3) is a masking material (1). In the masking material (1), at least the second member (3) contains a magnetic substance, and can be attached to the masked portion based on the magnetic force in the masking portion (22). Such masking material (1) can be used repeatedly.

Description

  The present invention mainly relates to a masking material and a masking method for masking a portion where coating is not desired during coating.

  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. In addition, if the masking tape that has been applied once is peeled off and then reapplied, it may not be possible to reapply 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.

Japanese Patent Laid-Open No. 61-257259

  However, the masking sheet described in Patent Document 1 is chlorinated polyethylene, nitrile rubber (NBR), ethylene-propylene-diene rubber (EPDM), chlorinated polyethylene (CPE), ethylene-vinyl acetate copolymer (EVA), chlorinated. Soft plastics such as sulfonated polyethylene and soft vinyl chloride are the main resin components. Masking sheets using such resin components, when used in harsh environments such as baking and immersion coating, the amount of deformation of the resin component increases and the degree of alteration of the resin component increases as the number of uses increases. As a result, it becomes impossible to maintain an accurate shape, making it unsuitable as a masking material.

  The present invention has been made in view of such a situation, and an object thereof is to provide a masking material that can be used repeatedly and a masking method using such a masking material.

  In order to achieve the above object, first, the present invention includes a first member made of an elastic material having a masking portion for contacting at least a part of the masked portion, and the first member can be attached and detached. And a second member to be held on the mask, wherein at least the second member contains a magnetic material, and can be attached to the masked portion based on a magnetic force in the masking portion. A masking material is provided (Invention 1).

  The masking material according to the above invention (Invention 1) is made of an elastic material as the first member that contacts the masked part, and the masking part is elastically deformed, so that it has high adhesion to the masked part and has excellent masking performance. Demonstrate. On the other hand, since the second member separate from the first member does not need to be made of an elastic material, it can be manufactured from a material having desired heat resistance, durability, and the like. Since the first member can be attached to and detached from the second member, the first member can be replaced with a new one even when the number of times the masking material is used and the first member is deformed. Thus, the masking portion can be maintained in an accurate shape, and therefore the masking material can be used repeatedly.

  In the said invention (invention 1), it is preferable that the holding force of the said 1st member by said 2nd member is larger than the adhesive force to the said to-be-masked part of the said masking material (invention 2). Thereby, only the second member can be gripped and attached to and removed from the masked portion, and handling becomes easy.

  In the said invention (invention 2), said 1st member and said 2nd member contain a magnetic body, and at least one part of the retention strength of said 1st member by said 2nd member is said 1st It is preferable to be based on the magnetic force acting between the member and the second member (Invention 3).

  In the said invention (invention 3), when the said masking part of said 1st member faces the said 2nd member side, said 1st member and said 2nd member repel each other, The first member and the second member are preferably magnetized (invention 4).

  In the above inventions (Inventions 1 to 4), the first member has a hole, and the second member is inserted into the hole of the first member and can be fitted to the hole. It is preferable that the projection has a columnar shape with a substantially constant thickness so that the projection can be inserted into and removed from the first member (Invention 5).

  In the said invention (invention 5), it is preferable that the magnitude | size of the hole of said 1st member is the same as the thickness of the convex part of said 2nd member, or is slightly small (invention 6).

  In the said invention (invention 1-6), it is preferable that said 1st member is a sheet form (invention 7).

  In the said invention (invention 5-7), said 1st member is a sheet form, Said 2nd member has a main-body part and said convex part, The main-body part of said 2nd member is The contact surface is in contact with the entire surface of one main surface of the first member, and the contact surface is substantially the same size as the main surface of the first member. It is preferable (Invention 8).

  In the said invention (invention 1-8), it is preferable that said 1st member does not contain silicone, a silicone resin, a fluorine, and a fluororesin (invention 9).

  In the said invention (invention 1-9), it is preferable that said 1st member contains an acrylic rubber (invention 10).

  In the said invention (invention 10), it is preferable that the said acrylic rubber is what has a crosslinked structure based on an amine type crosslinking agent (invention 11).

  In the above inventions (Inventions 10 and 11), the first member further contains a magnetic substance, and the content of the magnetic substance is 10 to 80 parts by volume with respect to 100 parts by volume of the acrylic rubber. Preferred (Invention 12).

  In the said invention (invention 1-12), it is preferable that said 1st member is 10-40 of Shore D hardness (invention 13).

  In the said invention (invention 1-12), it is preferable that said 1st member is 10-40 in Shore D hardness when the integration time in 180 degreeC environment is 13 hours (invention 14).

  In the said invention (invention 1-14), when the said 2nd member attaches / detaches the said masking material with respect to a to-be-masked part, the holding part which can hold | grip the said 2nd member is formed. It is preferable (Invention 15).

  2ndly this invention is based on the magnetic force which acts between the said masking material and the said to-be-masked part, elastically deforming the said masking part of said 1st member in the said masking material (invention 1-15). The masking method is characterized in that the masking material is adhered to the masked portion (Invention 16).

  In the masking material according to the present invention, since the first member can be attached to and detached from the second member, even if the first member is deformed by increasing the number of times the masking material is used, By exchanging one member for a new one, the masking portion can be maintained in an accurate shape. Therefore, the masking material can be repeatedly used in an optimal state.

It is a perspective view of the masking material which concerns on one Embodiment of this invention. It is a disassembled perspective view of the masking material which concerns on the same embodiment. It is sectional drawing of the masking material which concerns on the same embodiment.

Hereinafter, embodiments of the present invention will be described.
[Masking material]
As shown in FIGS. 1 to 3, the masking material 1 according to the present embodiment has a masking portion 22 for contacting a masked portion (a portion to be masked) and is a first member made of an elastic material. 2 and a second member 3 that detachably holds the first member 2. In addition, although the to-be-masked part in this embodiment is made into the circular part around the hole part which consists of metal materials, for example, metal materials, such as a steel plate and steel materials, it is not limited to this.

  In the masking material 1, at least the second member 3, preferably the second member 3 and the first member 2 contain a magnetic material, and the masking material 1 can adhere to the masked portion by the magnetic force of the magnetic material. It has become.

  The first member 2 is made of an elastic material, whereby when the masking material 1 is attached to the masked portion, the masking portion 22 of the first member 2 is elastically deformed and has high adhesion to the masked portion. Become. This reliably prevents the paint from entering between the masking portion 22 and the masked portion, and exhibits excellent masking performance.

  On the other hand, the second member 3 that is separate from the first member 2 does not need to be made of an elastic material, and therefore can be manufactured from a material having desired heat resistance, durability, and the like. Since the first member 2 is detachable with respect to the second member 3, even if the first member 2 is deformed by increasing the number of times the masking material 1 is used, the first member 2 is removed. By exchanging for a new one, the masking part 22 can be maintained in an accurate shape. Therefore, the masking material 1 can be repeatedly used in an optimum state.

  Here, the holding force of the first member 2 by the second member 3 is preferably larger than the adhesion force of the masking material 1 to the masked portion. As a result, even if the masking material 1 is removed from the masked portion by gripping only the second member 3, it is prevented that only the first member 2 remains in the masked portion. The material 1 is easy to handle.

  The holding force of the first member 2 by the second member 3 may be a magnetic force acting between the second member 3 and the first member 2, or may be the second member 3 and the first member 2. The fitting force with the member 2 may be sufficient, and both of these magnetic force and fitting force may be sufficient.

  The first member 2 in the present embodiment has a circular sheet shape in plan view, that is, a disk shape, and a hole 21 is formed at the center thereof. The sheet-like first member 2 has two main surfaces, and one main surface (the lower main surface in FIG. 3) has a masking portion 22 that contacts at least a part of the masked portion. The other main surface (upper main surface in FIG. 3) is an opposing surface 23 that faces the second member 3.

  The second member 3 in the present embodiment includes a columnar main body 31 and a columnar grip 32 provided on one end side of the main body 31 (the upper end side in FIG. 3). The cylindrical projection 33 is provided on the other end of the main body 31 (on the lower end in FIG. 3).

  An end surface on the convex portion 33 side of the columnar main body 31 is a contact surface 311 that comes into contact with the facing surface 23 of the first member 2. The contact surface 311 of the main body 31 of the second member 3 in this embodiment is in contact with the entire surface of the facing surface 23 of the first member 2. Thereby, when the magnetic force is acting between the 2nd member 3 and the 1st member 2, the retention strength of the 1st member 2 by the 2nd member 3 becomes a higher thing.

  In addition, the contact surface 311 of the main body 31 of the second member 3 in the present embodiment has substantially the same size as the facing surface 23 of the first member 2. That is, the outer diameter of the main body 31 of the second member 3 is substantially the same as the outer diameter of the first member 2. Thereby, when removing the 1st member 2 from the 2nd member 3, it has the outer edge part of the 1st member 2, and can remove the 1st member 2 easily. When the outer diameter of the first member 2 is smaller than the outer diameter of the main body 31 of the second member 3, it cannot be easily removed in this way. On the other hand, when the outer diameter of the first member 2 is larger than the outer diameter of the main body portion 31 of the second member 3, the adhesion force to the masked portion is increased at the peripheral portion of the masking portion 22 of the first member 2. There is a risk that paint will enter from there.

  The grip portion 32 of the second member 3 in the present embodiment has a diameter smaller than the diameter of the main body portion 31, thereby being easily gripped by hand. However, the present invention is not limited to such a form, and it is not necessary to provide the grip portion 32 as long as the main body portion 31 itself is easily gripped by hand. Further, the gripping portion 32 is not limited to a cylindrical shape, and may be, for example, a prismatic shape or a semicircular disc shape, and is appropriately determined in consideration of ease of gripping and manufacturing cost. Can be determined.

  The convex portion 33 of the second member 3 in the present embodiment has a diameter smaller than the diameter of the main body portion 31. The convex portion 33 of the second member 3 is inserted into the hole portion 21 of the first member 2 and is fitted to the hole portion 21. Further, the convex portion 33 of the second member 3 has a columnar shape with a substantially constant thickness so that it can be inserted into and removed from the hole portion 21 of the first member 2.

  The peripheral part of the second member 3 on the grip part 32 side of the main body part 31, the peripheral part of the grip part 32 opposite to the main body part 31, and the peripheral part of the convex part 33 opposite to the main body part 31 are chamfered. It may be done.

  The inner diameter of the hole portion 21 of the first member 2 is preferably the same as or slightly smaller than the outer diameter of the convex portion 33 of the second member 3. In this case, when the convex part 33 of the 2nd member 3 is inserted in the hole part 21 of the 1st member 2, both will closely_contact | adhere. With such a configuration, the holding force of the first member 2 by the second member 3 based on the fitting force between the second member 3 and the first member 2 is obtained.

  The thickness of the first member 2 may be 0.3 to 5.0 mm from the viewpoints of masking performance, ease of attaching / detaching the first member 2 to / from the second member 3, and manufacturing cost. It is particularly preferably 0.5 to 3.0 mm, and more preferably 0.7 to 2.0 mm.

[Material and manufacturing method of first member]
Although the 1st member 2 consists of an elastic material as mentioned above, it does not need to contain a magnetic body and may contain a magnetic body. When the magnetic material is contained, when the masking portion 22 of the first member 2 faces the second member 3 side, the first member 2 and the second member 3 repel each other, that is, The first member 2 and the second member so that the first member 2 and the second member 3 attract each other when the facing surface 23 of the first member 2 faces the second member 3 side. 3 is preferably magnetized. Thereby, the holding force of the 1st member 2 by the 2nd member 3 based on the magnetic force which acts between the 2nd member 3 and the 1st member 2 is obtained. Moreover, compared with the case where only the 2nd member 3 is magnetized, the magnetic force becomes strong as the whole masking material 1, and the adhesiveness to a to-be-masked part becomes high.

  The material (elastic material) constituting the first member 2 preferably does not contain silicone, silicone resin, fluorine, or fluororesin. When the first member 2 contains these components, the components are eluted from the first member 2 depending on the coating environment, and the components adhere to the masked portion or its surroundings and repel the paint. There is a fear.

  The elastic material constituting the first member 2 preferably contains rubber and / or thermoplastic elastomer as the main resin component. In addition, the “main resin component” in this specification refers to a main resin component among the resins constituting the member.

  Examples of rubber include natural rubber, synthetic isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), chloroprene rubber (CR), acrylonitrile-butadiene copolymer rubber (NBR), and butyl rubber (IIR). , Halogenated butyl rubber, acrylic rubber, urethane rubber, polysulfide rubber, and the like. One of these can be used alone, or two or more can be used in combination.

  Examples of the thermoplastic elastomer include olefin elastomers such as ethylene-propylene copolymer (EPR) and ethylene-propylene-diene copolymer (EPDM), and styrene series such as SBR made of a copolymer of styrene and butadiene. Elastomers, nitrile elastomers, butadiene elastomers, urethane elastomers, nylon elastomers, ester elastomers, modified products in which reactive sites (double bonds, anhydrous carboxyl groups, etc.) are introduced into these elastomers, etc. One kind can be used alone or two or more kinds can be used in combination.

  Among the above, acrylic rubber is preferable as the main resin component of the elastic material constituting the first member 2, and acrylic rubber having a crosslinked structure based on an amine-based crosslinking agent is particularly preferable. Since such a material is excellent in heat resistance, problems such as deformation and melting hardly occur even when the first member 2 is placed in a high temperature environment of about 180 ° C. during masking. In addition, since the above-described material is hard to increase in hardness even when placed in such a high temperature environment for a long time (excellent heat-resistant curability), the elasticity of the first member 2 is maintained, and the first member 2 It is difficult for paint to enter between the masking portion 22 and the masked portion. Therefore, the number of times the first member 2 itself can be used repeatedly increases.

  Here, “acrylic rubber” in the present specification means a homopolymer composed of a structural unit derived from (meth) acrylic acid ester or (meth) acrylic acid amide, (meth) acrylic acid ester and / or (meth). Copolymers composed of structural units derived from acrylic amides, and structural units derived from (meth) acrylic esters and / or (meth) acrylic amides and compounds other than (meth) acrylic esters (typically It is a compound having a polymerizable unsaturated bond, and in the present embodiment, it is composed of one or more selected from the group consisting of copolymers with structural units derived from “other polymerized compounds”. Means a material containing a polymer and / or a cross-linking reaction product of the polymer and a cross-linking agent and having mechanical properties as a rubbery elastic body That. In addition, in this specification, (meth) acrylic acid ester means both acrylic acid ester and methacrylic acid ester. The same applies to other similar terms.

  The structure of the ester group of the (meth) acrylic acid ester used to form the acrylic rubber is not particularly limited, and may be a (meth) acrylic acid alkyl ester or has a functional group at the alkyl position (meta) ) Acrylic acid alkyl ester may be used.

  Specific examples of alkyl (meth) acrylate esters include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate. Etc. Among these, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and methyl methacrylate are preferable from the viewpoint of handling and availability.

  Examples of the functional group possessed by the ester moiety include an alkoxy group, a hydroxyl group, an amino group, and an epoxy group. Specific examples of the (meth) acrylic acid alkyl ester having such a functional group include (meth) acrylic acid alkoxyesters such as (meth) acrylic acid methoxyethyl and (meth) acrylic acid ethoxyethyl; (meth) acrylic acid 2- Hydroxyethyl, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate, 4- (meth) acrylic acid 4- (Meth) acrylic acid hydroxyalkyl esters such as hydroxybutyl; (meth) acrylic acid monomethylaminoethyl, (meth) acrylic acid monoethylaminoethyl, (meth) acrylic acid monomethylaminopropyl, (meth) acrylic acid monoethylaminopropyl (Meth) acrylic acid such as Nonalkylaminoalkyl; (meth) acrylic acid glycidyl, acrylic acid 4- (glycidyloxy) butyl and the like, and (meth) acrylic acid epoxyalkyl such as (3,4-epoxycyclohexane-1-yl) methyl acrylate are exemplified. The

  On the other hand, examples of (meth) acrylic amide include (meth) acrylamide, N-methylacrylamide, N-methylmethacrylamide, N-methylolacrylamide, N-methylolmethacrylamide and the like.

  Among these, (meth) acrylic acid alkoxyalkyl esters are preferable, and methoxyethyl acrylate is particularly preferable among them. That is, the acrylic rubber preferably contains a polymer having a structural unit derived from an alkoxyalkyl ester of acrylic acid. In this case, it is easy to obtain an acrylic rubber excellent in heat-curing resistance. Moreover, it is easy to obtain acrylic rubber having high oil resistance.

  The (meth) acrylic acid ester and (meth) acrylic acid amide used for forming the acrylic rubber may be used alone or in combination of two or more. When the acrylic rubber contains a component based on a copolymer having a structural unit derived from a plurality of types of (meth) acrylic acid esters, the (meth) acrylic acid ester is a (meth) acrylic acid alkyl ester and (meth) It is preferable to contain an alkoxyalkyl ester of acrylic acid. Acrylic rubber is excellent in heat resistance and heat-resistant by containing a component based on a copolymer having a structural unit derived from (meth) acrylic acid alkyl ester and a structural unit derived from (meth) acrylic acid alkoxyalkyl ester. Acrylic rubber with excellent properties is easily obtained.

  The kind of the other polymerizable compound used for forming the acrylic rubber is not particularly limited as long as it can undergo a polymerization reaction with the (meth) acrylic acid ester. Typically, the compound which has the polymerizable unsaturated bond mentioned above is mentioned. Examples of such compounds include olefins such as ethylene, propylene, n-butene, norbornene, and cyclohexene; aromatic compounds having an ethylenically unsaturated bond such as styrene and derivatives thereof; (meth) acrylic acid, crotonic acid, cinnamic acid, and the like [Alpha], [beta] -ethylenically unsaturated monocarboxylic acid having 3 to 12 carbon atoms; [alpha], [beta] -ethylenically unsaturated dicarboxylic acid having 4 to 12 carbon atoms such as fumaric acid, maleic acid, itaconic acid and citraconic acid; Monoesters of α, β-ethylenically unsaturated dicarboxylic acids having 3 to 11 carbon atoms and alkanols having 1 to 8 carbon atoms such as monoethyl acid, monocyclopentyl fumarate, monobutyl maleate, monobutyl itaconate; vinyl acetate, acrylonitrile And the like. Of the other polymerizable compounds, α, β-ethylenically unsaturated dicarboxylic acid is contained as a structural unit in the form of dicarboxylic anhydride in the acrylic rubber polymer, and is hydrolyzed during crosslinking. A carboxyl group may be generated.

  Among these, compounds having a carboxyl group such as α, β-ethylenically unsaturated monocarboxylic acid and α, β-ethylenically unsaturated dicarboxylic acid can form a reaction point with the amine-based crosslinking agent described later. Therefore, it is preferable. The carboxyl group in this compound may be in the form of an acid anhydride as described above.

  When other polymerizable compounds are used to form the acrylic rubber, the other polymerizable compounds may be used singly or in combination of two or more.

  In the case where the (meth) acrylic acid ester and other polymerizable compounds used as required are composed of a plurality of types of compounds, the proportion of the structural units derived from these compounds in the acrylic rubber is arbitrary, and the acrylic What is necessary is just to set suitably considering the use etc. of the masking material containing rubber | gum. For example, when there is a large proportion of (meth) acrylic acid alkyl ester having a bulky alkyl group such as a butyl group, an acrylic rubber having a low embrittlement temperature tends to be obtained, and other polymerizable compounds having a carboxyl group When the ratio is large, the degree of the crosslinking reaction with the amine-based crosslinking agent increases, and a hard acrylic rubber tends to be obtained.

  As described above, the acrylic rubber preferably has a crosslinked structure based on an amine-based crosslinking agent. The “amine-based crosslinking agent” in the present specification means a bifunctional or higher amine-based compound, and is not particularly limited as long as it is a compound having two or more nitrogen atoms having at least one active hydrogen. An acrylic rubber having a crosslinked structure based on such an amine-based crosslinking agent is prevented from being excessively softened even when exposed to a high temperature environment of 180 ° C., for example. Moreover, compared with the crosslinking structure based on another crosslinking agent, for example, an isocyanate type crosslinking agent, it is excellent in heat-resistant curability. For this reason, even if the 1st member 2 is used repeatedly, a masking function does not fall easily.

  Examples of the amine-based crosslinking agent include 1,4-butanediamine, 1,9-nonanediamine, 2-methyl-1,8-octanediamine, 1,4-diaminocyclohexane, triethylenetetramine, tetraethylenepentamine, and ethylenediamine. N, N-dicinnamylidene-1,6-hexanediamine, trimethylenediamine, hexamethylenediaminecarbamate, 3,9-bis (3-aminopropyl) -2,4,8,10-tetraoxa-2-spiro [5 .5] Aliphatic polyamines such as undecane; Aromatic polyamines such as diaminodiphenylmethane, xylylenediamine, phenylenediamine, diaminodiphenylsulfone; carbazic acid, 6-aminohexylcarbamic acid, 4,4′-methylenebis (cyclohexylamine) carbamide acid Amino carbamic acid; and the like salts of the polyamines and amino carbamic acid. The amine-based crosslinking agent may be composed of one kind of compound or may be composed of a plurality of kinds of compounds. Among these, as the amine-based crosslinking agent, aminocarbamic acid and / or a salt thereof is preferable from the viewpoint of improving heat-resistant curability.

  The degree of crosslinking based on the amine-based crosslinking agent in the acrylic rubber (in other words, the density of crosslinking points) is not particularly limited. When the density of cross-linking points is excessively low, there is a concern that it will be difficult to obtain an acrylic rubber excellent in heat-resistant curability. On the other hand, when the density of cross-linking points is excessively high, the first member 2 is excessively hardened in relation to the content of other components (particularly magnetic substances) contained in the first member 2. It is difficult to deform, and there is a concern that the first member 2 cannot follow the shape of the masked portion and the masking function is lowered. Therefore, the density of cross-linking points should be appropriately set in consideration of the composition of the material constituting the first member 2.

  In addition, it is preferable that the content of the uncrosslinked amine-based crosslinking agent remaining in the acrylic rubber included in the first member 2 is as small as possible. When such an uncrosslinked amine-based crosslinking agent is heated during masking to cause a crosslinking reaction, the density of crosslinking points in the acrylic rubber increases during masking, and the Shore D hardness of the first member 2 increases. Is brought about. If the degree of hardness increase is significant, the masking function of the first member 2 may be lowered.

  From the viewpoint of promoting the reaction of the crosslinking reaction by the crosslinking agent, the acrylic rubber preferably contains a crosslinking accelerator. Examples of the crosslinking accelerator include amino compounds such as triethylamine and tetramethylbutanediamine, stannous chloride, dimethyltin dichloride, trimethyltin hydroxide, di-n-butyltin dilaurate, dibutyltin diacetate, dibutyltin sulfide, Metal compounds such as ferric iron, iron acetyl acetate, cobalt naphthenate, bismuth nitrate, lead oleate, and antimony trichloride can be used.

  When the first member 2 contains a magnetic material, examples of the magnetic material include metals such as iron, nickel, cobalt, alloys thereof (for example, stainless steel) or oxides, strontium ferrite, barium ferrite, manganese Ferrites such as zinc ferrite, nickel zinc ferrite, copper zinc ferrite and the like, alnicos such as aluminum-nickel-cobalt alloy, rare earths such as rare earth-transition metal (eg, SmCo, SmFeN, NbFeB), etc. Examples include ferromagnetic materials. 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.

  When heat treatment is performed during masking as in baking coating, the magnetic material is preferably made of a ferromagnetic material having a Curie temperature higher than the heating temperature in this heat treatment.

  The shape of the magnetic material is preferably a powder shape from the viewpoint of ease of molding of the first member 2. 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 particle size of the magnetic material can be measured by, for example, a Coulter counter method.

  When the 1st member 2 contains a magnetic body, 10-80 volume parts are preferable with respect to 100 volume parts of main resin components (acrylic rubber), and 15-70 volume parts are especially preferable, 20-60 volume parts is further more preferable. When content of a magnetic body exceeds 80 volume parts, the 1st member 2 will become hard and there exists a possibility that elasticity may be impaired. On the other hand, if the content of the magnetic material is 10 parts by volume or more, the holding force by the second member 3 and the adhesion force to the masked part can be improved by the magnetic force of the first member 2.

  The first member 2 may contain an anti-aging agent. In particular, when it contains acrylic rubber, it is preferable to contain an anti-aging agent. The type of anti-aging agent is not particularly limited as long as the antioxidant effect is high. For example, an amine-ketone anti-aging agent such as a 2,2,4-trimethyl-1,2-dihydroquinoline polymer; Aromatic secondary amine antioxidants such as 4,4-bis (α, α-dimethylbenzyl) diphenylamine, N, N′-di-2-naphthyl-p-phenylenediamine; zinc of 2-mercaptobenzimidazole Benzimidazole anti-aging agents such as zinc salt of 2-mercaptomethylbenzimidazole; dithiocarbamate anti-aging agents such as nickel dibutyldithiocarbamate; phosphite anti-aging agents such as tris (nonylphenyl) phosphate Is mentioned. The anti-aging agent may be composed of one kind or two or more kinds. The anti-aging agent preferably contains 4,4-bis (α, α-dimethylbenzyl) diphenylamine from the viewpoint of heat resistance and the like.

  Although content of an antioxidant is not specifically limited, Usually, it is preferably 0.001 to 1 part by mass, and 0.01 to 0.7 part by mass with respect to 100 parts by mass of the main resin component. Particularly preferred.

  The first member 2 may further contain additives such as a dispersant as other components. 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. The content of these components is not particularly limited, and may be set as appropriate so as not to lower the masking function by the first member 2.

  When the 1st member 2 contains the acrylic rubber which has a crosslinked structure based on an amine type crosslinking agent, as a manufacturing method of the 1st member 2, the material for forming the 1st member 2 is shape-processed. The method of heating the obtained molded product in a state before the crosslinking reaction of the amine-based crosslinking agent proceeds to advance the crosslinking reaction of the amine-based crosslinking agent contained in the molded product is easy to produce. From the viewpoint of stability of quality, an example of the method is as follows.

  First, a polymer related to acrylic rubber, an amine-based cross-linking agent, and further containing an additional component such as a magnetic material and an anti-aging agent, if necessary, before the cross-linking reaction between the polymer and the cross-linking agent proceeds. A composition is prepared. Specifically, the above polymer, amine-based crosslinking agent, and optionally a magnetic substance (preferably magnetic powder) and / or additives are added using a Henschel mixer, single or twin screw extruder, Banbury mixer, roll, etc. And melt mixing.

  Next, a molding process is performed on the composition to roughly form the shape of the first member 2. As the molding method, for example, the first member 2 having the shape described above may be directly molded by injection molding, or extruded into a sheet shape by extrusion molding, and then the first member 2 having the shape described above by punching. May be punched out. The first member 2 can be obtained by heating the molded product thus obtained to advance the crosslinking reaction. In addition, when the magnetic body is not magnetized, the first member 2 obtained in the above manufacturing process or obtained may be magnetized by a known method.

In the above production method, the heating temperature for proceeding the crosslinking reaction (hereinafter referred to as “crosslinking temperature”) should be appropriately set depending on the type of the crosslinking agent, etc. It is preferable to set the temperature equal to the maximum heating temperature (hereinafter referred to as “use temperature”) that the masking material 1 receives when using the mask. When the crosslinking temperature is excessively lower than the use temperature, the crosslinking reaction is not completed in the manufacturing stage of the first member 2, and the crosslinking is performed when the first member 2 is heated during the use of the masking material 1. There is a concern that the reaction will proceed. In this case, the first member 2 may be hardened and the masking function may be deteriorated. From the viewpoint of stably avoiding such a problem, it is preferable that the crosslinking temperature T ₁ is a use temperature T ₂ −30 ° C. or higher, that is, the following formula is satisfied.
T ₁ > T ₂ −30 ° C.

From the viewpoint of more stably avoiding the above problem, the temperature difference ΔT (= T ₁ −T ₂ ) is preferably 40 ° C. or higher, and more preferably 50 ° C. or higher. However, when the crosslinking temperature T ₁ is excessively high, there is a possibility that problems such as the molded product to stick to the base during the heating occurs, setting the crosslinking temperature T ₁ of in consideration of this point Is preferred. The heating time for advancing the crosslinking reaction of the molded product is arbitrary, and may be appropriately set in consideration of the type of crosslinking agent and the crosslinking temperature. Also in this case, the molded product is such that when the masking material 1 is heated during use, the crosslinking reaction proceeds in the first member 2 and the hardness of the first member 2 does not increase excessively during use. It is preferable to set the heating time in consideration of substantially completing the crosslinking reaction.

[Physical properties of the first member]
(1) Shore D hardness The Shore D hardness of the first member 2 is preferably 10 to 40, particularly preferably 11 to 35, and further preferably 12 to 30. When the Shore D hardness of the first member 2 is within such a range, the masking portion 22 of the first member 2 follows the masked portion well, and excellent masking performance is exhibited.

  In addition, the first member 2 has a Shore D hardness (also referred to as “post-heated Shore D hardness” in the present embodiment) of 10 to 40 when the accumulated time in an environment of 180 ° C. is 13 hours. It is preferable that Since the Shore D hardness after heating of the first member 2 is 40 or less, the first member 2 was brought into contact with the masked portion even when the first member 2 was repeatedly used under heating. Sometimes, it becomes easy for the first member 2 to follow the shape of the masked portion. From the viewpoint of stably improving the followability of the first member 2 to the masked portion, the Shore D hardness after heating is preferably 35 or less, and more preferably 30 or less. When the 1st member 2 contains the acrylic rubber which has a crosslinked structure based on an amine type crosslinking agent, Shore D hardness after a heating tends to be 40 or less, and will be a value sufficiently lower than 30 if a composition is adjusted appropriately. It is also possible.

  On the other hand, when the Shore D hardness after heating is less than 10, when the first member 2 is fixed to the masked portion depending on the elastic component and the masking material 1 is removed from the masked portion, the first member 2 is removed. May remain in the masked portion. Or when the 1st member 2 adheres to the 2nd member 3 and the 1st member 2 is removed from the 2nd member 3, it is also worried that the removal will become difficult. From the viewpoint of stably avoiding such a problem, the post-heating Shore D hardness of the first member 2 is preferably 10 or more, and more preferably 12 or more.

(2) Bending Softness The first member 2 preferably has a bending resistance of 6.0 N or less. In the present embodiment, the “flexibility” is a Gurley type tester defined in JIS L1096 (1999) 8.20.1 when the first member 2 is formed into a sheet having a thickness of 1 mm. Means the bending resistance measured by using the Gurley method. When the bending resistance is 6.0 N or less, it becomes easy to improve the followability of the first member 2 to the masked portion when the masking material 1 is attached to the masked portion. From the viewpoint of further stably improving the followability, the bending resistance of the first member 2 is preferably 5.5 N or less, and more preferably 5.0 N or less. The lower the bending resistance of the first member 2 is, the better from the viewpoint of improving its followability. However, when it is excessively low, the masking material 1 or the first member 1 is used as in the case of the Shore D hardness described above. Since there is a concern that a problem may occur at the time of removing the member 2, it is preferable that the bending resistance of the first member 2 is usually 0.5 N or more.

(3) Breaking strength The first member 2 preferably has a breaking strength measured based on JIS K7127 (1999) (measurement environment: 23 ° C., 50% RH) of 2 to 20 MPa. When the breaking strength is 2 MPa or more, the first member 2 may be cracked even when a force is applied to extend the first member 2 during the attaching / detaching operation of the masking material 1 or the first member 2. The possibility of causing a problem such as breakage can be reduced. From the viewpoint of more stably reducing the possibility of problems during the attachment / detachment operation, the breaking strength of the first member 2 is more preferably 3 MPa or more, and further preferably 4 MPa or more. On the other hand, when the breaking strength is excessively high, the bending strength of the first member 2 is usually 20 MPa or less because the above-mentioned bending resistance may tend to be excessively increased.

(4) Elongation at break When the first member 2 was molded into a sheet having a thickness of 1 mm, it was measured based on JIS K7161 (1994) (measuring environment: 23 ° C., 50% RH) at 20 mm / min. The elongation at break when stretched (hereinafter abbreviated as “breaking elongation”) is preferably 50% or more. Even when a force that stretches the first member 2 is applied during the attaching / detaching operation of the masking material 1 or the first member 2 because the breaking elongation is 50% or more, the first member 2 is broken. The possibility of causing such problems can be reduced. From the viewpoint of more stably reducing the possibility of occurrence of problems during the attaching / detaching operation, the breaking elongation of the first member 2 is preferably 60% or more, and more preferably 100% or more. From the viewpoint of avoiding the above problem, the higher the breaking elongation of the first member 2 is, the better. However, if it is excessively high, the above-mentioned bending resistance may tend to increase excessively. The breaking elongation of the first member 2 is usually preferably 2000% or less.

(5) Dimensional Change Rate The first member 2 preferably has a small dimensional change rate in the in-plane direction of the surface (masking part 22) in contact with the masked part even when heated during masking. Here, the dimensional change rate is such that the length of one side in the plane direction before heating of the first member 2 is X ₁ , and the length of the one side in the plane direction after heating is X ₂ . It is represented by the following formula.
Dimensional change rate (%) = {1- (X ₂ / X ₁ )} × 100

  The rate of dimensional change when the cumulative time under a 180 ° C. environment is 13 hours is preferably 5.0% or less, particularly preferably 3.0% or less, and 1.5% or less. More preferably. If the dimensional change rate of the first member 2 is within the above range, it can be said that the dimensional stability of the first member 2 (masking material 1) is excellent. In this case, since the material does not easily shrink even when heated, the masking performance after heating is excellent.

[Material and manufacturing method of second member]
As the material of the second member 3, a material that contains a magnetic substance and can retain the above-described shape and has desired heat resistance, durability, and the like is selected. The second member 3 can be, for example, a molded body of a magnetic body, a sintered body of magnetic powder, a molded body of a material containing magnetic powder and resin (hereinafter referred to as “composite material C”), or the like.

  The second member 3 does not need to be a single member, and may be a combination of different members. In that case, materials may differ for every member, for example, what combined the member which consists of a material containing said magnetic body, and the member which does not contain a magnetic body may be used. However, the member made of a material containing a magnetic body preferably constitutes all or part of the main body 31 of the second member 3.

  When the masking material 1 according to the present embodiment is used under a heating process such as baking coating, the magnetic body needs to have a Curie temperature higher than the temperature of the heating process. Since the temperature of the heating process in baking coating is usually 120 to 160 ° C., the Curie temperature of the magnetic body needs to be higher than that. If the Curie temperature of the magnetic material is lower than the temperature of the heating step, the magnetic force of the magnetized magnetic material is reduced during the heating step, and the masking material 1 may be detached from the masked portion.

  Examples of the molded body of the magnetic body include metals such as iron, nickel, and cobalt, and alloys (for example, stainless steel) or oxide castings, forgings, and cuttings.

  A typical magnet is mainly exemplified as the sintered body of the magnetic powder. For example, ferrites such as strontium ferrite, barium ferrite, manganese zinc ferrite, nickel zinc ferrite and copper zinc ferrite, alnicos such as aluminum-nickel-cobalt alloys, rare earth-transition metals (eg, SmCo, SmFeN, And a magnet obtained by sintering a powder of a ferromagnetic material such as a rare earth material such as NbFeB).

  The magnetic powder that can be used in the composite material C is the same as the magnetic powder that can be used in the first member 2. On the other hand, the resin that can be used in the composite material C may be a thermosetting resin or a thermoplastic resin as long as it can obtain desired heat resistance and durability in combination with magnetic powder. There may be.

  When the masking material 1 according to the present embodiment is used under a heating process such as baking coating, for example, the thermosetting resin is preferably used because it is excellent in heat resistance. Examples of the thermosetting resin include epoxy resin, phenol resin, urea resin, melamine resin, unsaturated polyester resin, resorcinol resin, furan resin, polyimide resin, diallyl phthalate resin, polyurethane resin, silicone resin, allyl ester resin, and the like. 1 type can be used individually or in mixture of 2 or more types.

  On the other hand, even if it is a thermoplastic resin, if it has melting | fusing point higher than the temperature of the said heating process, it can be used. Since the temperature of the heating step in baking coating or the like is usually 120 to 160 ° C., a thermoplastic resin having a melting point higher than that temperature may be used, preferably 170 ° C. or higher, particularly preferably 180 ° C. or higher, and further Preferably, a thermoplastic resin having a melting point of 200 ° C. or higher is used.

  Examples of the thermoplastic resin as described above include polyamides such as nylon 4, nylon 6, nylon 46, nylon 66, nylon 610, nylon 69, nylon 612, nylon 1212, nylon 11, nylon 12, nylon MXD6, and nylon 6T. 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. Among the above, a polyamide resin excellent in dimensional stability and chemical resistance is preferable, and nylon 6 is particularly preferable. The melting point of polyamide resin is generally 170 ° C. or higher, and the melting point of nylon 6 is about 220 ° C.

  The content of the magnetic substance in the composite material C is preferably 10 to 80 parts by volume, particularly preferably 15 to 70 parts by volume, with respect to 100 parts by volume of the resin constituting the composite material C. More preferably, it is 60 parts by volume.

  The composite material C may contain additives such as a dispersant in addition to the above-described resin and magnetic substance.

  When the first member 2 does not contain a magnetic material, the magnetization direction of the second member 3 is not particularly limited (when the masked part is not magnetized), but the first member 2 contains a magnetic material. As described above, the first member 2 and the second member 3 are attracted to each other when the facing surface 23 of the first member 2 faces the second member 3 side. The member 2 and the second member 3 are preferably magnetized.

  The second member 3 can be manufactured by a conventional method. When the second member 3 is made of the composite material C, it is preferably manufactured by compression molding if the resin used is a thermosetting resin, and is manufactured by injection molding if the resin used is a thermoplastic resin. It is preferable. Magnetization of the second member 3 (and the first member 2) can be performed by a conventional method, and can be performed using a known magnetizing / demagnetizing device or the like.

[Physical properties of masking materials]
The magnetic fixing force of the masking material 1 is preferably 0.5 to 20N, particularly preferably 1 to 15N, when the masked portion is made of a stainless steel plate as an example. When the magnetic fixing force of the masking material 1 is 0.5 N or more, it is possible to reduce the possibility that the masking material 1 attached to the masked portion will fall off during use. Further, since the magnetic fixing force of the masking material 1 is 20 N or less, the operation of removing the masking material 1 from the masked portion after use or when changing the mounting position becomes easy.

  Here, the magnetic fixing force of the masking material 1 is 23 ° C. and 50% RH (relative humidity) when the masking material 1 is adhered to a stainless steel plate (1.5 mm thickness, SUS430 plate) as a masked portion. Under the environment, using a tensile testing machine (product name “Tensilon” manufactured by Orientec Co., Ltd.), the stainless steel plate is fixed to the base, the masking material is fixed with the chuck, and the stainless steel plate and the masking material are fixed at a speed of 300 mm / min. Means the force (N) required to pull apart.

  The magnetic force of the masking material 1 should be appropriately set according to the purpose of use, but is usually preferably 20 to 100 mT. If the magnetic force of the masking material 1 is 20 mT or more, it is possible to reduce the possibility that the masking material 1 attached to the masked part will fall off during use. Moreover, when the magnetic force of the masking material 1 is 100 mT or less, the work of removing the masking material 1 from the masked portion becomes easy. The magnetic force here refers to a magnetic force measured with a gauss meter at a distance of 1 cm from the masking portion 22 of the masking material 1.

[Masking method]
An example of a masking method using the masking material 1 according to an embodiment of the present invention will be described below. The masked portion is a circular portion around the hole in the automotive steel plate before painting, but is not limited thereto. Such a circular portion can be used as a ground terminal portion of an automobile.

  First, as shown in FIGS. 1 and 3, the first member 2 of the masking material 1 is set on the second member 3. Specifically, the convex portion 33 of the second member 3 is moved into the hole portion 21 of the first member 2 until the contact surface 311 of the second member 3 comes into contact with the facing surface 23 of the first member 2. insert.

  While the convex portion 33 of the second member 3 of the masking material 1 set as described above is inserted into the hole of the masked portion, the masking portion 22 of the first member 2 of the masking material 1 contacts the masked portion. Let At this time, the masking material 1 adheres to the masked portion by the magnetic force. Further, the first member 2 made of an elastic material is elastically deformed, whereby the masking portion 22 is in close contact with the masked portion.

  In this state, painting and heat-curing of the paint, optionally water-sharpening and subsequent heat-curing are repeated as many times as desired. The masking material 1 exhibits excellent masking performance when the elastically deformed masking portion 22 is in close contact with the masked portion. When the process of the last painting and the heat curing of the paint is completed, the gripping portion 32 of the second member 3 is held and the masking material 1 is removed from the masked portion. At this time, if the holding force of the first member 2 by the second member 3 is larger than the adhesion force of the masking material 1 to the masked portion, only the first member 2 may remain in the masked portion. Effectively prevented.

  The removed masking material 1 can be repeatedly used for masking in the same manner as described above until the first member 2 cannot be maintained in an accurate shape due to deformation or alteration. In addition, when the first member 2 is deformed, altered, or the like and cannot maintain an accurate shape, the first member 2 is removed from the second member 3 and the new first member 2 is replaced with the first member 2. It can be set on the second member 3 and repeatedly used for masking in the same manner as described above. The first member 2 may be replaced with a new one each time the masking material 1 is used once.

  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. The paint is not limited to a paint for coloring, and may be a sealer, for example.

  The embodiment described above is described for facilitating understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  For example, the masking material 1 is not limited to a circular shape in a plan view, and can have various shapes depending on the shape of the masked portion. Moreover, the hole part 21 of the 1st member 2 and the convex part 33 of the 2nd member 3 are not restricted to a planar view circular shape, but can be made into an elliptical shape or a desired polygonal shape. Furthermore, the 1st member 2 has a convex part instead of the hole part 21, and the 2nd member 3 is a recessed part which the convex part which the 1st member 2 has instead of the convex part 33 fits. You may have.

  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.

[Example 1]
A structural unit derived from ethyl acrylate (EA), a structural unit derived from n-butyl acrylate (BA) and a structural unit derived from methoxyethyl acrylate (MEA) in a molar ratio of 1: 7: 4. Containing 100 parts by mass of a copolymer containing a trace amount of a structural unit derived from a compound having a carboxy group (hereinafter referred to as “acrylate molar ratio”), and an amine crosslinking agent. Acrylic rubber was prepared in a state before the crosslinking reaction proceeded, comprising 1 part by mass of 6-aminohexylcarbamic acid.

  Anti-aging agent comprising 4,4-bis (α, α-dimethylbenzyl) diphenylamine in an amount of 0.5 parts by mass with respect to 100 parts by mass of the acrylic rubber, and 47 parts by volume of strontium with respect to 100 parts by volume of the acrylic rubber A magnetic material made of ferrite was mixed with the acrylic rubber to obtain a composition as a forming raw material. Using this composition, a molded body having a shape indicated by reference numeral 3 in FIG. 2 was obtained by injection molding and magnetization using a mold in a magnetic field.

  The obtained molded body was put in a thermostatic bath whose furnace was maintained at 170 ° C., and the molded body was heated at 170 ° C. for 3 hours. Thereafter, the molded body was taken out from the thermostatic bath and allowed to cool to room temperature to obtain a second member. The diameter of the main body (contact surface) of this second member was 30 mm, the height of the main body was 6 mm, the diameter of the convex part was 6 mm, the length was 5 mm, the diameter of the gripping part was 14 mm, and the height was 10 mm. It was.

  Separately, a sheet-like molded body having a thickness of 1 mm was obtained by injection molding and magnetizing a composition as the same molding raw material as described above using a mold different from the above in a magnetic field.

  The obtained molded body was put into a thermostatic bath whose furnace was maintained at 170 ° C., and the molded body was heated at a crosslinking temperature of 170 ° C. for 3 hours. Thereafter, the molded body is taken out from the thermostatic bath, allowed to cool to room temperature, and then the shape shown by reference numeral 2 in FIG. A first member having a disk shape with a diameter of 30 mm and a thickness of 1 mm was obtained.

  The convex part of the 2nd member was made to fit in the hole part of the obtained 1st member, and the masking material of Example 1 was obtained.

[Example 2]
Example 2 was the same as Example 1 except that the material of the first member was changed from acrylic rubber containing magnetic powder to polyester resin (product name “Hytrel 4047N” manufactured by Toray DuPont). A masking material was obtained.

[Comparative Example 1]
A conventional masking tape (manufactured by 3M, product name “Fine Line Masking Tape 2800”) was prepared and used as the masking material of Comparative Example 1.

[Comparative Example 2]
Only the second member produced in the same manner as in Example 1 was used as the masking material of Comparative Example 2.

[Comparative Example 3]
When preparing the forming raw material for obtaining the first member and the second member of Example 1, the magnetic material made of strontium ferrite is not mixed, and the magnetic material is formed without being magnetized. A masking material of Comparative Example 3 was obtained in the same manner as in Example 1 except that the masking material was not used.

[Test Example 1] Immersion test The masking material produced in the examples and comparative examples was mounted on a flat stainless steel plate (SUS304; thickness 0.5 mm) having a hole with a diameter of 6 mm (second member of the masking material). Was inserted into a hole in the stainless steel plate, and the masking portion of the first member was brought into close contact with the stainless steel plate), and this was used as a sample. In addition, about the masking material (tape) of the comparative example 1, it affixed using a 2 kg roller. The sample was immersed in a bath filled with an electrodeposition paint (manufactured by Nippon Paint Co., Ltd., product name “Power Top U Excel 250”; liquid temperature 23 ° C.), and the sample was taken out 10 minutes after the start of immersion.

Subsequently, the masking material was removed from the stainless steel plate, and the presence or absence of the paint adhering to the masking portion of the stainless steel plate was confirmed. The evaluation criteria are as follows.
A: No adhesion F: Adhesion Evaluation results are shown in Table 1. In addition, about the sample of the comparative examples 1 and 3 evaluated that there was adhesion (F) in this evaluation, evaluation of the test examples 2 and 3 was not implemented.

[Test Example 2] Repeated Use Test For the samples of Example 1 and Comparative Example 2 whose evaluation was A in Test Example 1, the masking material attachment-immersion-masking material removal operation performed in Test Example 1 was repeated 50 times. It was. In addition, about the masking material of Example 1, the said 1st member was replaced | exchanged for a new article for every said operation | work, and said repeated use test was done. The presence or absence of the coating material adhesion to the masking part of the stainless steel plate after performing the above operation 50 times was confirmed. The evaluation criteria are as follows.
A: No adhesion F: Adhesion Evaluation results are shown in Table 1.

[Test Example 3] Measurement of Shore D Hardness of First Member The first member of the masking material prepared in Examples and Comparative Examples was left in a 180 ° C. environment for 40 minutes and then in a 23 ° C. environment. The shore D hardness was measured with a type D durometer (DD2-D, manufactured by Kobunshi Keiki Co., Ltd.) before and after a heating test (an integrated time at 180 ° C. of 13 hours) in which a cycle of standing for 20 minutes was repeated (JIS According to K7215). The results are shown in Table 1.

  As can be seen from Table 1, the masking materials obtained in Examples 1 and 2 were excellent in masking performance, and the masking performance was maintained even after 50 repeated uses.

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

DESCRIPTION OF SYMBOLS 1 ... Masking material 2 ... 1st member 21 ... Hole part 22 ... Masking part 23 ... Opposing surface 3 ... 2nd member 31 ... Main-body part 311 ... Contact | adherence surface 32 ... Gripping part 33 ... Convex part

Claims (16)

A masking material comprising a first member made of an elastic material having a masking part for contacting at least a part of the masked part, and a second member for detachably holding the first member. And
At least the second member contains a magnetic material,
The masking material can be attached to the masked portion based on magnetic force in the masking portion.   The masking material according to claim 1, wherein a holding force of the first member by the second member is larger than an adhesion force of the masking material to the masked portion. The first member and the second member contain a magnetic material,
The at least part of the holding force of the first member by the second member is based on a magnetic force acting between the first member and the second member. Masking material.   When the masking portion of the first member faces the second member side, the first member and the second member are arranged such that the first member and the second member repel each other. The masking material according to claim 3, wherein the member is magnetized. The first member has a hole;
The second member is inserted into the hole of the first member, and has a convex portion that can be fitted to the hole.
The masking material according to claim 1, wherein the convex portion has a columnar shape with a substantially constant thickness so that the convex portion can be inserted into and removed from the first member.   The masking material according to claim 5, wherein the size of the hole of the first member is the same as or slightly smaller than the thickness of the convex portion of the second member.   The masking material according to claim 1, wherein the first member has a sheet shape. The first member is a sheet,
The second member has a main body portion and the convex portion,
The main body portion of the second member has a contact surface in contact with the entire surface of one main surface of the first member, and the contact surface is in contact with the main surface of the first member. The masking material according to claim 5, wherein the masking material has substantially the same size.   The masking material according to claim 1, wherein the first member does not contain silicone, silicone resin, fluorine, or fluororesin.   The masking material according to claim 1, wherein the first member contains acrylic rubber.   The masking material according to claim 10, wherein the acrylic rubber has a crosslinked structure based on an amine-based crosslinking agent. The first member further contains a magnetic substance,
The masking material according to claim 10, wherein the content of the magnetic material is 10 to 80 parts by volume with respect to 100 parts by volume of the acrylic rubber.   The masking material according to claim 1, wherein the first member has a Shore D hardness of 10 to 40.   2. The masking material according to claim 1, wherein the first member has a Shore D hardness of 10 to 40 when an accumulated time in an environment of 180 ° C. is 13 hours.   The grip part which can hold said second member when said masking material is attached to and detached from said part to be masked is formed in said second member. The masking material described.   The masking material is masked based on a magnetic force acting between the masking material and the masked portion while elastically deforming the masking portion of the first member in the masking material according to claim 1. A masking method characterized by adhering to a part.

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